Membrane-associated carbonic anhydrase activity in the kidney of CA II-deficient mice.

Carbonic anhydrase II-deficient mice offer a possibility to study the localization along the nephron of membrane-associated carbonic anhydrase (CA) activity without interference from the cytoplasmic enzyme. We studied the localization of CA in kidneys from CA II-deficient and control mice by immunocytochemistry (CA II) and histochemistry. Cytoplasmic staining was found in convoluted proximal tubule, thick limb of Henle, and principal and intercalated cells of collecting duct in the control animals but was absent in the CA II-deficient mice. In cells with cytoplasmic staining the cell nuclei were stained. Intense histochemical activity was associated with apical and basolateral membranes of convoluted proximal tubule, first part of thin limb, thick limb, and basolateral membranes of late distal tubule. In collecting ducts of control animals, the basolateral cell membranes of intercalated cells were the only clearly stained membranes. In CA II-deficient animals one type of intercalated cell was stained most intensely at the apical membranes and another only at the basolateral. We suggest that the former corresponds to Type A intercalated cells secreting H+ ions to the luminal side and the latter to Type B cells secreting H+ ions to the basolateral side.


Application of two-color immunofluorescence staining to demonstration of T-cells and HLA-DR-bearing cells in rheumatoid synovitis.

We studied the localization of T-cells and HLA-DR antigen-bearing (DR+) cells in rheumatoid synovitis by employing an improved two-color immunofluorescent staining (TCIF) technique. With this technique we have successfully identified DR+ activated T-cells in the inflammatory synovium. T-cells expressed HLA-DR antigen when they were in contact with DR+ antigen-presenting cells (APC). In addition, activated T-cells showed characteristic distribution within the synovium: they were found around high endothelial venules, within lymphoid follicles, and in hyperplastic synovial lining, suggesting their involvement in the development of rheumatoid synovial lesions via interaction with synovial DR+ APC lineage cells. These findings may contribute to better understanding of the role of activated T-cells in the histogenesis of rheumatoid synovitis, a typical chronic inflammatory lesion.


Demonstration of dopamine-immunoreactive cells in the proximal convoluted tubule of gerbil (Meriones unguiculatus) kidney.

We investigated dopamine immunoreactivity in the kidney of gerbils (Meriones unguiculatus). For that purpose a sensitive and selective antibody against glutaraldehyde-conjugated dopamine was applied. Dopamine-immunoreactive cells were found in the epithelium of the proximal convoluted tubule, where these cells revealed a typical segment-like distribution pattern. Dopamine-immunoreactive precipitates were small and concentrated at the apical pole of the labeled cells. This study has directly identified dopamine as a constituent of certain cells of the proximal convoluted tubule in gerbils. The functional significance of dopamine in these cells is discussed in relation to the present view of renal dopaminergic actions.


Intra- and extracellular localization of hyaluronic acid and proteoglycan constituents (chondroitin sulfate, keratan sulfate, and protein core) in articular cartilage of rabbit tibia.

To demonstrate the intra- and extracellular localization of hyaluronic acid (HA) in articular cartilage of the rabbit tibia, biotinylated HA binding region, which specifically binds to the HA molecule, was applied to the tissue. In comparison with the localization of HA, that of chondroitin sulfate (CS), keratan sulfate (KS), and the protein core (PC) of the proteoglycan was examined by immunohistochemistry. Strong positive staining for HA was detected in chondrocytes located in the transition between the superficial and middle zones of the tissue. Pre-treatment with chondroitinase ABC, keratanase II, or trypsin enhanced the stainability for HA in peri- and intercellular matrices. Immunohistochemistry with or without enzymatic pre-treatment demonstrated that immunoreactivity for CS, KS, and PC was distinctly discerned in chondrocytes and in the extracellular matrix located in the middle and deep zones. In particular, the immunoreactivity for KS and PC was augmented by pre-treatment with chondroitinase ABC not only in chondrocytes but in the extracellular matrix located in the middle and deep zones. Microbiochemical analysis corresponded well with histochemical and immunohistochemical results. These results suggest that HA is abundantly synthesized and secreted in chondrocytes located in the transition between the superficial and middle zones.


Immunohistochemical localization of superoxide dismutases in fetal and neonatal rat tissues.

We investigated the developmental profile of copper-zinc and manganese superoxide dismutase (CuZnSOD and MnSOD) in tissue sections obtained from fetal (Day 12 to 21 of gestation) and neonatal (Day 0 and 6) rats. Tissues were stained immunohistochemically with specific antisera against the respective rat SODs. There was a general trend towards richness of SODs in the epithelial linings and metabolically active sites, although differential distribution between the two SODs also existed. At Day 12 of gestation, immunoreactivity for both SODs was detected in the cardiomyocytes but not in other tissues. Hepatocytes expressed CuZnSOD at Day 14 and MnSOD at Day 17. By Day 18 CuZnSOD was detected in the epithelial cells of the gastrointestinal tract, respiratory tract, pancreatic islets, kidneys, and adrenals. These tissues exhibited MnSOD staining at Day 19. CuZnSOD occurred in the epithelia of the thyroid, thymus, and salivary glands at Day 19, while MnSOD was seen at Day 21. The increase in intensity of the staining for SODs occurred no later than postnatal Day 0, indicating that most tissues accumulated SODs during late gestation. Breathing atmospheric oxygen during early extrauterine life did not appreciably intensify the SOD staining. These results suggest that perinatal increase in SODs occurs as a general mechanism of preparation for birth.


Complete penetration of antibodies into vibratome sections after glutaraldehyde fixation and ethanol treatment: light and electron microscopy for neuropeptides.

To develop a method for quantitative electron microscopic immunocytochemistry on neural tissue of CNS, we tested the extent to which ethanol treatment would improve the penetration of immunoreagents through vibratome sections fixed in high concentrations of glutaraldehyde without compromising ultrastructure. Transverse or sagittal vibratome sections (60-80 microns) of spinal cord perfused with 1% formaldehyde plus 1% or 2.5% glutaraldehyde were washed in 50% ethanol for 0-70 min and stained to reveal immunoreactivity for neuropeptide Y (NPY). Semi-thin (1 micron) or ultra-thin sections were used to assess the depth to which NPY nerve fibers in the dorsal horn were stained. Without ethanol washing, immunoreactive nerve fibers were visualized only in the surface 5-10 microns of transverse or sagittal vibratome sections. In transverse vibratome sections, NPY nerve fibers, which ran perpendicular to the cut surfaces of the sections, were entirely stained after a 30-min wash in 50% ethanol. The numbers of NPY-immunoreactive varicosities and synapses were comparable at the surfaces and in the centers of the vibratome sections. In sagittal sections, where NPY nerve fibers ran parallel to the cut surfaces, fibers in the centers of vibratome sections could not be labeled even after 70 min in 50% ethanol. Substance P- and enkephalin (Enk)-immunoreactive nerve fibers could also be completely stained in transverse sections of spinal cord or medulla oblongata after 30-min exposure to ethanol. Ethanol washing had no significant deleterious effects on ultrastructure, although the amount of cytoplasmic matrix in neurons decreased with increasing exposure. These results indicate that washing with 50% ethanol for at least 30 min allows immunoreagents to penetrate completely through nerve fibers fixed with high concentrations of glutaraldehyde, as long as the fibers have cut ends at both surfaces of a vibratome section. This technique makes possible quantitative electron microscopic immunocytochemical studies and is proving a useful tool for defining synaptic connections in the CNS.


Nerve-induced secretion of glycoconjugates from cat submandibular glands: a correlative study with lectin probes on tissues and saliva.

Horseradish peroxidase-conjugated lectins were used on tissue sections to localize the main secretory glycoproteins in cat submandibular glands and on Western blots to evaluate their movement into saliva with selective nerve stimulation. Central acinar cells bound lectins from Arachis hypogaea (PNA) specific for the terminal disaccharide Gal beta 1, 3GalNac, Griffonia simplifolia (GSA I-B4) specific for terminal alpha Gal, and Lotus tetragonolobus (LTA) specific for fucose. Lectins from Limax flavus (LFA) specific for sialic acid and Dolichos biflorus (DBA) specific for terminal alpha GalNac reacted preferentially with demilunar cells, whereas apical granules in striated ducts were recognized principally by LTA. Parasympathetic stimulation promoted the release of lectin-reactive glycoconjugates from both central and demilunar cells. In contrast, sympathetic stimulation caused almost complete release of LTA-reactive granules in striated ducts and only moderate secretion from demilunar cells. Lectin blots of stimulated saliva discriminated many of the constituent bands, providing information about their glycosylation. Several bands were common to both parasympathetic and sympathetic saliva, and many bands gave wider ranges of lectin binding than anticipated from the histochemistry. The major component in parasympathetic saliva was a glycoconjugate of less than 12 KD which reacted with every lectin tested. Lectin blots of sympathetic saliva showed a prominent diffuse LTA-reactive band around 33 KD, which was attributed to tissue kallikrein. The identity and cellular origin of most bands in stimulated submandibular saliva are still unclear but the technique shows considerable promise for improving the recognition and characterization of individual glycoconjugates.


Expression of the first calcitonin/CGRP gene in spontaneous and transplanted rat medullary thyroid carcinoma: a comparison of dot-blot analysis, in situ hybridization, and immunohistochemistry.

Calcitonin (CT) and calcitonin gene-related peptide (CGRP) are encoded by a single gene, the CALC-I gene. They are expressed in the thyroid and in the nervous system by alternative splicing of the pre-messenger RNA derived from the CALC-I gene. In medullary thyroid carcinoma (MTC), a malignancy derived from the calcitonin-producing C-cells in the thyroid, production of calcitonin and CGRP is a common feature. We investigated the CT and CGRP production of four spontaneous MTCs transplanted three to four times and 14 MTC lines transplanted for several years in WAG/Rij rats, a strain with hereditary MTC. The expression of CT and CGRP in the spontaneous and in the transplanted tumors was studied by means of RNA in situ hybridization (RISH), dot-blot analysis, and immunohistochemistry. A down-regulation of CT production in transplanted compared with spontaneous tumors was observed, but an inverse relation between CT and CGRP mRNA content in both spontaneous and transplanted tumors was not observed. In this study, RISH proved to be as sensitive as dot-blot analysis to detect gene expression in tissue samples. The different approaches of analyzing the gene expression in tissue samples (the cellular localization of gene expression by ISH vs the analysis of an extract of a total tissue sample with dot-blot analysis) showed that each technique is equal in value and that they are complementary to each other.


Nature and distribution of mineral-binding, keratan sulfate-containing glycoconjugates in rat and rabbit bone.

The presence of keratan sulfate (KS) and KS proteoglycans in bone has been demonstrated in birds and rabbits but comparison with other animal species has not been investigated. The nature and distribution of mineral-binding, KS-containing glycoconjugates in rat and rabbit bone were investigated with a monoclonal antibody (MAb 5D4) specific for KS. Mineral-binding proteins were extracted from the mineralized bone with 0.4 M EDTA without guanidine-HCl (E-extract). On Western blot analysis of SDS-polyacrylamide gel electrophoresis, rat E-extract gave a weak 5D4-reactive band, M(r) 66,000-68,000, whereas rabbit E-extract produced two major reactive populations of small and large molecular size; one population consisted of two closely spaced bands at M(r) 61,000-63,000 and 66,000-68,000, and the other population consisted of one band at approximately M(r) 200,000. The identity of KS chains was further established by the sensitivity of these bands to keratanase II (Bacillus sp. Ks 36) and endo-beta-galactosidase. Immunocytochemistry with MAb 5D4 showed that, in rat bone, staining associated with the mineral phase was limited to the walls of osteocytic lacunae and bone canaliculi, whereas the remainder of the mineralized matrix lacked staining. In contrast, in rabbit bone the staining was distributed over the entire portion of the mineralized matrix with focal accumulation of staining in the wall of the lacunocanalicular system. These results indicate that rat bone contains a mineral-binding, KS-containing glycoconjugate with preferential localization in the wall of the lacunocanalicular system, whereas rabbit bone contains at least two or possibly three types of KS-containing glycoconjugates distributed over the entire portion of the mineralized matrix.


Fluorescence image cytometry of nuclear DNA content versus chromatin pattern: a comparative study of ten fluorochromes.

This study is intended to be the first step of an in situ exploration of the intranuclear DNA distribution by image cytometry (SAMBA) with several fluorochromes. The nuclear DNA content and the chromatin pattern, revealed by ten fluorochromes (HO, DAPI, MA, CMA3, OM, QM, AO, EB, PI, and 7-AMD), were analyzed on mouse hepatocytes fixed by the Boehm-Sprenger procedure optimal for preserving the chromatin pattern. The question was whether fluorochromes specific to DNA make it possible to accurately quantitate the total nuclear DNA content when the chromatin pattern is preserved. Only HO and MA were found to provide satisfactory quantitation of nuclear DNA content, as assumed by both a small CV and a 4c to 2c ratio equal to 2. PI, EB, 7-AMD, and OM provided higher CV values, although the 4c to 2 c ratio was still equal to 2. QM, AO, CMA3, and DAPI provided non-reproducible and non-stoichiometric nuclear DNA content measurements under the fixation conditions used. The intranuclear and the internuclear SD of the fluorescence intensities describing the fluorescence pattern of the 2c hepatocytes proved to vary according to both the basepair specificity and the binding mode of the fluorochromes. The results reported here argue in favor of an external binding of 7-AMD to DNA and an increased quantum yield of QM when bound to AT-rich DNA. For PI, EB, 7-AMD, and OM, the measured DNA content increased with the fluorescence distribution heterogeneity. This correlation was not observed with other fluorochromes and is suggested to result from decreased fluorochrome accessibility to DNA when the chromatin is condensed. This study demonstrates that under conditions that preserve chromatin organization, only HO for AT-rich DNA and MA for GC-rich DNA can be used, alone or in combination, to measure nuclear DNA content. With other fluorochromes, either the measured DNA content or the chromatin pattern is assessed in suboptimal conditions when fluorescent image cytometry is used.


A new acrylic resin formulation: a useful tool for histological, ultrastructural, and immunocytochemical investigations.

We describe a new formulation for a hydrophilic resin, mostly composed of glycol methacrylate and hydroxypropyl methacrylate and here referred to as bioacryl, that allows the performance of morphological and immunohistochemical investigations at both light and electron microscopic levels. Immunolocalizations performed on bioacryl-embedded tissues are characterized by high specificity with virtually absent background staining. Finally, the new resin yields satisfactory fine-structural preservation, resulting in ultrastructural images of better quality than those obtained with Lowicryl K4M.


Lesbian erotics: the utopian trope of Donne's "Sapho to Philaenis".

Famous for its self-assertive masculinity, John Donne's love poetry nonetheless includes a verse elegy which stands alone not only in his work but also in the entire literary production of the Renaissance for its celebration and defense of a passionate lesbian relation binding the two women of its title. No editorial grounds exist for denying Donne's authorship of "Sapho to Philaenis"; rather the interpretive task is to reconstitute the poem's significance in period terms. The task is complicated by Donne's penchant for flouting literary and social convention as he successively overturns Ovid's influential portrayal of Sappho as an aging voluptuary reclaimed for heterosexuality, the virulent homophobia of Renaissance humanists, and the coy idealizations and transient evocation given to lesbian affectivity by the very few Renaissance writers (including Shakespeare) who touched on the subject at all. When "Sapho to Philaenis" is set in the context of Donne's other love elegies in verse as productions by a young intellectual moving in sophisticated London circles and writing for a coterie audience, lesbianism looks like a master trope for positively resolving a dilemma that confounded Montaigne and many other authors of the age. Could the perfections of love and friendship be united in a relation of equality between two persons? Gender hierarchy and separate socialization precluded a heterosexual construction of any such equality in the Renaissance, and the greater opprobrium cast on male homosexuality in this era must have influenced Donne's decision to figure his equal lovers and friends as a lesbian couple. Yet the disclosive power of "Sapho to Philaenis" goes far beyond the entailments of a specific choice of poetic representation. Donne really undertakes to imagine the pleasures, sustenance, and ideological implications by which lesbianism, as a mode of loving and being, resists patriarchal disposition and diminution of women. Donne anticipates the advances of twentieth-century feminists (Colette, Kofman, Irigaray) as he poetically articulates possibilities and knowledge that were otherwise denied expression by Renaissance culture and its exponents.


Sodomy and kingcraft in Urania and Antony and Cleopatra.

Despite his description of sodomy as a horrible crime that a king is "bound in conscience neuer to forgiue," James I pursued the affections of a string of young and handsome "favourites" on whom he lavished gifts, titles, and power. Relying on the evidence of the King's own letters and frank comments from his Puritan critics, most historians assume that his relations with some of these men were sexual. The King's friendship with Robert Carr (who was later made Earl of Somerset), coupled with his estrangement from Queen Anne, may have been an inspiration for at least two literary accounts of kingship confounded by sex: Lady Mary Wroth's Urania (1621) and Shakespeare's Antony and Cleopatra (1608). Wroth describes a duke who is made politically vulnerable by his love for a young man that leaves him "issue-les." The rise and fall of this disloyal companion closely resembles that of Somerset and would seem to indicate Wroth's belief that the King's relationship with the Earl was sexual. Antony and Cleopatra is in many ways a reflection of Jacobean court extravagance and decadence. Cleopatra, despite her sex, seems to fill the same role in political and sexual scandal as did Somerset; and Antony's vacillation between pleasure and duty recalls a certain Renaissance discourse on sodomy and "kingcraft".


Not since Sappho: the erotic in poems of Katherine Philips and Aphra Behn.

The presentation of sexuality in poetry may be masked by the use of conventional literary devices that obscure as well as reveal the poems' erotic content. Traditional readings of Katherine Philips' and Aphra Behn's poetry have ignored or denied the lesbian aspects of their verse by dismissing them as asexual representations of well-known literary conventions. This paper argues for a recognition of the ways in which these poetic conventions present a complex and sophisticated lesbian sexuality and also comment on other taboo aspects of human sexual relations.


Seeing sodomy: Fanny Hill's blinding vision.

One of the oddest and most erotic moments in Cleland's Fanny Hill occurs when Fanny is knocked "senseless" by a voyeuristic vision of two young men having anal intercourse. This sodomitical passage demonstrates a dominant culture's strong phobic attraction to a socially peripheral Other against which it defines itself. The passage also represents two types of transgression. On one level, it records an inversion of sex, gender, and class paradigms that structure bourgeois subjectivity. On another level, the passage also transgresses signification itself, exploding as well as inverting those paradigms, in a movement that recalls Barthes's distinction between the coded "studium" of the pornographic and the uncoded "punctum" of the erotic. This transgressive exemption from meaning might well be read, in a Barthesian sense, as true sexual enfranchisement in that, for Barthes, the liberation of sexuality requires the release of sexuality from meaning, and from transgression as meaning.


The sodomitical muse: Fanny Hill and the rhetoric of crossdressing.

Cleland's Fanny Hill, banned for centuries largely as a result of a passage depicting male sodomy, has been the focus of several critical approaches since it was republished in the United States in 1963. Critical readings by Nancy K. Miller and Randolph Trumbach in particular indicate that Fanny's persona itself is a "drag" act. While asserting this, no critic has traced the textual complexity of this persona, which is apparent in Cleland's use of figurative language and is accessible through close reading only.


"The voice of nature" in Gray's Elegy.

Thomas Gray's "Elegy Written in a Country Churchyard" commemorates a problematic sexuality that traditional readings of the poem's "melancholy" usually ignore. By reconsidering the poem in light of theories of abjection, this essay uncovers the powerful poetic expression of a sexuality at odds with mid-century culture and shows how the poet's awareness of his own homosexuality shaped the familiar features of the most popular poem of the eighteenth century.


Tradition and the individual sodomite: Barnfield, Shakespeare, and subjective desire.

This article compares Shakespeare's sonnets with those written by Richard Barnfield in order to examine the possibility of homoerotic subjectivity in early Renaissance England. Social constructionist debates about sexual subjectivity have convincingly argued that "the homosexual"--the person defined by homosexuality--did not exist before the Enlightenment. The sequences of Shakespeare and Barnfield, both of which deal with homoerotic desire, suggest that homoerotic desire could indeed play a role in defining the individuated subject prior to the Enlightenment. However, the ways in which they use homoeroticism also suggest that subjectivity was defined in radically different ways during the period.


Body, costume, and desire in Christopher Marlowe.

All the desired youths in Marlowe come clothed in favors, the tokens of older and richer men's yearning. These bribes and rewards, often feminine or effeminate ornaments, not only beautify the already gorgeous bodies of young men, but also label and augment their value and their power. The moment of virility's blooming, in adolescence, is seen as a time when boys can negotiate favorable terms of entry into the realms of manhood by the seductive use of their glamor. For their part, desirous men are distracted from the affairs and cares of state by their nostalgic encounters with girlish boys, at worst, to the extent that their own patriarchal power is compromised by sodomitic dalliance. Marlowe's involvement in these plots is iterative and committed.


Verse letters to T.W. from John Donne: "By you my love is sent".

Relying on an audience of one for their impact, the verse letters of John Donne are closer to autobiography than anything else in his poetry. Among the most tender of these lyrics are the verse letters written to a young man named Thomas Woodward, whose older brother was one of Donne's closest friends. Using sexual metaphors, the poems reflect a homoerotic undercurrent and demonstrate affection that most readers of Donne associate only with his heterosexual love poems.


"Masculine love," Renaissance writing, and the "new invention" of homosexuality.

Contrary to the dominant claim in gay studies now that homosexuality is a relatively new historical "invention," the Renaissance had a definite recognition of a distinct homosexuality, acknowledged at least by those who were willing to face and discuss the subject frankly. A key example of that awareness is the earlier term "masculine love," which seems to have been particularly prominent in the Renaissance as a language for a male homosexual orientation. Significant differences have clearly occurred in the homosexual situation over time, and homosexuality can never be discussed totally independent of historical and social conditions, but the "new-inventionism" currently prevailing in gay studies has serious problems of concept and method and needs careful examining.


Femme on the streets, butch in the sheets? Lesbian sex-roles, dyadic adjustment, and sexual satisfaction.

Recent research suggests that butch-femme role playing in lesbian couples has diminished and been replaced with androgynous attitudes and behaviors. Are lesbians, however, able to maintain an androgynous approach when it comes to lovemaking? Or does the bedroom give way to the powerful influence of traditional gender-based norms for sexual behavior? What implications does the choice of sex-roles have for relationship and sexual satisfaction in lesbian couples? The present study of 111 lesbians explores the relationship between sex-role self-perceptions, sexual satisfaction, and sexual fulfillment. Findings indicate that lesbians perceive themselves as significantly more feminine when they are interacting sexually than their overall or global sex-role perception. Furthermore, lesbians who view themselves as either androgynous or feminine in a sexual context had the highest level of sexual satisfaction and dyadic adjustment among all four sex-role groups.


Freud and sexual reorientation therapy.

Contrary to certain psychoanalytic interpretations, Freud himself generally resisted the possibility or desirability of sexual reorientation therapy. Yet his understanding of the origins and nature of homoeroticism does not suggest that conversion therapy is impossible. Although he did not believe homoeroticism to be an inherent impediment to human accomplishment and fulfillment neither did he see it as having the full value of heteroeroticism. For these reasons he did not altogether rule out the desirability or possibility of conversion therapy for some individuals even if he did not believe that it could be psychoanalysis alone that could redirect sexual orientation.


Lesbianism and choice.

Why does it matter whether a woman can choose whether to be lesbian? I argue by illustration that, first of all, it does make good sense to see the option to be lesbian as genuine for women in a fairly common sort of circumstance; that recognizing the genuineness of this option, however, does not impute to such women major control over their lives; that choosing to be lesbian may actually narrow rather than expand one's present options; and that nevertheless it is important to acknowledge such choices for their potentialities, in community, to change the meaning of "lesbian" in liberatory ways.


The gay pediatrician: a report.

Since no articles in the medical literature could be found dealing with the subject of the gay pediatrician, a complete bibliographic search was conducted in order to find information about gay health professionals. Using both manual and computerized methods of access to information in many data bases, much pertinent material was found. Reports were accessed which demonstrated that gay pediatricians most certainly exist and that, in addition to their standard role in pediatric and adolescent medicine, they have special and unique contributions to make to the care of our nation's 2.9 million gay youth. Gay pediatricians need to be accepted as valuable professionals by peers and by society. Whenever possible, gay pediatricians need to act as role models to our gay youth. Pediatricians who happen to be gay have much to contribute to medicine.


Attitudes toward minorities: a comparison of homosexuals and the general population.

As a prelude to a media campaign to improve the public image of gays, a gay rights organization in Columbus, Ohio, constructed a questionnaire to assess perceptions of and attitudes toward gays and various other minority groups including blacks, Jews, women, communists, and recovering alcoholics. The questionnaire was administered to two samples in the central Ohio area: a sample of the greater Columbus population at large, and a sample of gays and lesbians. This article reports on the comparative findings from these two samples.


Passing and social support among gay men.

One hundred sixty-six gay men responded to a questionnaire survey which asked them to describe their social networks and the extent to which they 'passed' (were assumed to be heterosexual) among network members. Most gay men were known as gay to most members of their networks; however, friends, siblings and persons close to respondents were more likely to be aware of their homosexuality than co-workers, parents, and more distant relatives. Gay men were more satisfied with social support available from those who knew of their sexual orientation. The author concludes that passing has important and complex effects on the social networks of gay men.


Adult responses to child behavior and attitudes toward fathering: gay and nongay fathers.

This study examines gay and nongay fathers' responses to instruments measuring parenting style and orientation to the fathering role. Fifty-three respondents (24 gay and 29 nongay fathers) completed two surveys, and responses to each were analyzed. Both groups of fathers were found to have a developmental orientation toward their role as fathers, and no discernible parenting style could be found to distinguish one group from the other. Thus, gay and nongay fathers were found to be more similar than different with regard to parenting styles and attitudes toward fathering. This finding supports previous work (Bigner & Jacobsen, 1989a, 1989b) and expands the available knowledge based on the parenting styles of homosexual parents.


Public endorsement of restrictions on three aspects of free expression by homosexuals: socio-demographic and trends analysis 1973-1988.

The willingness of the public to endorse proposals to remove gay-positive books from library shelves, to dismiss college teachers who are homosexuals, and to prohibit public speaking by homosexuals was examined. A socio-demographic analysis aggregating the entire period 1973 through 1988, and an analysis of trends over the period, were undertaken using data from the General Social Surveys. Responses to survey questions concerning homosexuals were compared with responses to similar questions concerning other unpopular groups, and to questions which called upon the respondent to make a moral judgment concerning homosexual relations. A significant decline over the period was found in the public's willingness to endorse restrictions on homosexuals, and on each of the other unpopular groups used for comparison. Level of education appeared to be a strong indicator of a more tolerant attitude. Paradoxically, negative moral attitudes toward homosexual relations did not decline. Bias in the wording of the General Social Surveys' questions concerning the moral dimension of homosexuality may have distorted these results, however. The public's moral attitude toward homosexual behavior does appear to be quite labile from year to year, suggesting that concerted efforts to educate the public on this subject can have an important and rapid effect.


"Man's words" and manly comradeship: language, politics, and homosexuality in Walt Whitman's works.

Critical assessments of Walt Whitman's works either emphasize his sexual themes while ignoring his political ideas or they focus on the poet's politics but ignore his poetics of corporeality. Recent studies that do discuss both politics and sexuality in Whitman's works do not devote much attention if any to the poet's theory of language as it appears in his An American Primer. This essay explores the complex intersections among sexuality, politics, and language in Whitman's works, illustrating how the poet consistently correlated his linguistic, sexual, and political metaphors, constantly relating the health and the sexual potency of the male body with the power of language, the efficacy of literature, and the strength of the states in the United States. Underlying these multiple metaphors and poetic intentions is the poet's homosexual vision. It constitutes the basis of his linguistic theory, his hope of an ideal democratic union, and his plea for sexual equality. To Whitman, America needed male-to-male friendships to free it from materialistic vulgarities and to ensure its perpetuation.


Visions and revisions of reality: reflections on sex, sexuality, gender, and gender variance.

Varying perceptions of gender, sex, and sexuality are investigated, using several examples, from the Pokot of East Africa to the Tewa Indians in New Mexico. The role that labels play in the acquisition of gender identity is also explored; and the influence of Cartesian dualism is challenged, suggesting a need to expand Euro-American conceptions of gender.


The relationship of instrumentality and expressivity to sexual orientation in women.

The study reported here investigated the relationship between Instrumentality (I) and Expressivity (E) (two personality variables related to sex roles), sexual orientation, occupational level and marital status. The hypothesis was that women high in I and low in E may find traditional heterosexual relationships to be in conflict with their personality traits, and that a lesbian choice may offer a way of life more in keeping with such traits. The study used a sample of 159 women, and found that neither I nor E alone, nor I x E, could predict sexual orientation. A weak relationship was found between I and housewifery, such that women who were married with children and did not have a job outside the home tend to score lower on I. Expressivity bore no relationship to any of the variables. Women who were high on I and low on E were not more likely to be lesbian. The study concludes that there is no relationship between I, E, and sexual orientation; also that it is inappropriate to use housewives as a heterosexual comparison group for lesbian women.


Are gay men artistic? A review of the literature.

There is a popular perception that gay men are artistic. Although art historians and others have documented the substantial contribution to art made by gay men, the existence of a unique gay sensibility remains controversial. Mental health practitioners who work with gay men have addressed aesthetic sensibility in the childhood of gay men, but not the role of art in their adult lives. A literature search on the relationship between homosexuality and artistic ability and/or achievement shows that there is little scientific data addressing this subject. Reasons for the lack of literature as well as suggestions for future research are offered.


Researcher-participant relationships in journal reports on gay men and lesbian women.

To assess the ethical nature of research relationships between investigators and gay and lesbian participants we reviewed 351 reports on homosexuality in three major and 75 miscellaneous journals from 1974 to 1988. We found that authors rarely involved participants beyond the role of providing data, generally did not report conditions of consent, rarely reported feedback, and almost never indicated using data to promote social action. In addition, authors typically relied on the term "subjects" and on a depersonalized, decontextualized writing style. There were some differences among journals, over time, and among authors' disciplines. Male authors tended to study men exclusively, whereas female authors' relation to participants' gender was more varied. Believing that research with gay men and lesbian women should not detract from their emancipation, we offer some recommendations for research practice and report-writing which are designed to better protect research participants and to produce more valid knowledge.


Tolerance to host minor histocompatibility antigens after allogenic bone marrow transplantation. Specific donor-host unresponsiveness is maintained by peripheral tolerizing cells.

The development of graft-host tolerance after allogeneic bone marrow (BM) transplantation is more demanding than the acquisition of self-tolerance because both donor-derived mature T cells and immature thymocytes encounter host Ag. The mechanism involved in tolerization of mature T cells, contained in unmanipulated BM, remains undefined. In previous experiments, we showed in vivo unresponsiveness to host minor histocompatibility Ag (MiHA) in immunocompetent chimeras obtained after MiHA-incompatible BM transplantation. In this study, we wanted to determine: first, what was the specificity of this graft-host unresponsiveness, and second, whether peripheral cells were involved in tolerization? LP recipients were irradiated (9, 5 Gy), injected with 10(7) undepleted BM cells from B10 donors and studied 100 to 150 days later. (B10-->LP) chimeras were immunized in vivo and restimulated in vitro with cells displaying one or multiple incompatible MiHA. In bulk culture experiments, chimeras demonstrated specific CTL unresponsiveness to host MiHA but responded normally to third party MiHA. In limiting dilution analysis conditions, chimeras showed a profound deficit, but not a complete absence of anti-host CTL precursor. Studies with congenic stimulators/targets showed that graft-host tolerance was induced against both immunodominant (e.g., H-3.2) and nonimmunodominant (e.g., H-8.2) MiHA although at the CTL precursor level, it was more complete against the former. Furthermore, chimera spleen cells inhibited the generation of CTL activity against host- and donor-type MiHA but not against third party Ag. This specific suppressor activity was not T cell dependent, and was mediated by radiosensitive cells that are not found in freshly explanted organs from normal mice. Taken together, our results suggest that peripheral tolerization can be a remarkably efficient process to maintain tolerance to MiHA after BM transplantation. Thus, peripheral tolerizing mechanisms may contribute not only to the induction of tolerance to Mls superantigens or to the product of transgenes (if expressed at high levels) but also to a wide array of MiHA.


Selective association between MHC class I-restricted T cell receptors, CDS, and activated tyrosine kinases on thymocytes undergoing positive selection.

Developing T cells undergo distinct selection processes that determine the TCR repertoire. Positive selection involves the differentiation of immature thymocytes capable of recognizing antigens complexed with self-MHC molecules to mature T cells. Besides the central role of TCR engagement by MHC in triggering selection; the interaction of CD8 and CD4 with MHC class I and class II, respectively; is thought to be important in regulating the selection process. To study potential mechanisms involved in positive selection of CD8+ cells, we have analyzed mice expressing a unique transgenic TCR. The transgenic receptor recognizes the HY male Ag in the context of the MHC class I molecule, H2-Db. We describe that CD8 and the TCR are selectively associated in thymocytes of mice expressing the restricting MHC, but not in thymocytes of mice expressing a nonrestricting MHC. pp56lck and pp59fyn, the tyrosine kinases associated with CD8 and TCR, respectively, were found to be present in this complex in an activated form. No comparable TCR-CD4 complex formation was found in thymuses undergoing positive selection to CD8+ cells. The formation of a multimolecular complex between CD8 and TCR, in which pp56lck and pp59fyn are activated, may initiate specific signaling programs involved in the maturation of CD8+ cells.


Effect of class I MHC binding peptides on recognition by natural killer cells.

NK cells can recognize and destroy a broad range of cells, including many tumor cells and virally infected cells, yet spare most normal cells. Identification of the target structure recognized by these cells has proved elusive. An attractive hypothesis is that, unlike B cells and T cells that recognize a specific foreign marker, NK cells respond to the absence of a "self" marker. Class I MHC molecules have been implicated as the self markers whose absence can trigger lysis. We show here that normal cells are lysed on incubation with IL-2-activated NK cells if peptides that can bind to the class I MHC molecules of the normal cells are also included in the assay, and speculate that this binding is somehow removing a self marker that normally protects a cell from lysis. NK cells were derived from splenocytes of young (5 to 8 wk old) athymic nude BALB/c (H-2d) or nude C57Bl/6 (H-2b) mice incubated with 1000 U/ml rIL-2, and target cells were derived from splenocytes of normal BALB/c or C57Bl/6 mice incubated with Con A. Peptides were from xenogeneic, viral, self, and mutated self protein sequences and included sequences specific for Kd, Kb, Db, and Ld. All peptides increased lysability of those targets to which they could bind.


Induction of apoptosis by monoclonal antibody anti-APO-1 class switch variants is dependent on cross-linking of APO-1 cell surface antigens.

Apoptosis, programmed cell death, was previously shown to be induced by the mAb anti-APO-1 (IgG3, kappa) by binding to the APO-1 cell surface Ag, a new member of the nerve growth factor/TNF receptor superfamily. To investigate the role of the Ig H chain Fc regions we compared induction of apoptosis by the original mAb IgG3 anti-APO-1 with anti-APO-1 F(ab')2 fragments and different anti-APO-1 isotypes (IgG1, IgG2b, IgG2a, and IgA) isolated by sequential sublining. We found that IgG3 was the most active isotype; IgG1, IgG2a, and IgA showed intermediate activity, and IgG2b and F(ab')2 were inactive. Cytotoxic activity of the inactive or less active antibody preparations was fully reconstituted by protein A, anti-mouse Ig, or anti-mouse Ig F(ab')2, respectively. Thus, APO-1-mediated induction of apoptosis was dependent on efficient cross-linking of APO-1 cell surface Ag, indirectly augmented by anti-APO-1 Fc-Fc self-aggregation. Because of their different in vitro activity we selected IgG3-, IgG2b-, and IgA anti-APO-1 to test their antitumor activity against solid human B lymphoblastoid tumors in SCID mice. The isotypes showed a different serum half-life (IgG3: 9.2-10.4 days, IgG2b: 1.9-2.6 days, and IgA: 14.1-29.2 h) and a different initial tumor localization 4 h after i.p. injection (IgG3 around the blood vessels, IgG2b homogeneously, and IgA heterogeneously distributed in the tumor). All antibody preparations induced tumor regression by induction of apoptosis, even IgG2b anti-APO-1 inactive in vitro without cross-linking. The activity of IgA anti-APO-1, which did not mediate complement-dependent cytotoxicity or antibody-dependent cellular cytotoxicity indicates that apoptosis may be used as the main if not the only mechanism of induction of tumor regression in vivo. As with in vitro, IgG3 anti-APO-1 was the most effective isotype also in vivo. This result suggests that cross-linking of APO-1 on the tumor cell surface may also be required for tumor regression by apoptosis in vivo. Taken together, our data show that selective targeting of apoptosis to tumors may be an efficient antitumor mechanism.


Basement membrane and its components on lymphocyte adhesion, migration, and proliferation.

During inflammation and recirculation, lymphocytes migrate into tissues by traversing the capillary endothelium, a process known as extravasation. After crossing the endothelial cells, lymphocytes come into contact with the basement membrane, which is a specialized layer of extracellular matrix containing predominantly laminin, collagen type IV, entactin, and heparan sulfate proteoglycans. In tissue invasion by inflammatory cells and metastatic tumor cells, the basement membrane serves as a substratum for cell adhesion and migration. However, the role of basement membrane in lymphocyte extravasation remains unclear. In this study, we investigated the effect of basement membrane on lymphocyte adhesion, migration, and proliferation, using matrigel as a model for basement membrane. We observed that matrigel promotes both lymphocyte adhesion and migration, with entactin primarily responsible for promoting adhesion and laminin for promoting migration. In addition, activation of lymphocytes by anti-CD3 enhances their adhesion and migration on matrigel-coated substratum. We also observed that matrigel inhibits the proliferation of lymphocytes stimulated by Con A. Furthermore, we demonstrated that laminin is the matrigel component responsible for inhibiting lymphocyte proliferation. However, matrigel has no effect on the proliferation of lymphocytes stimulated by LPS. These results suggest that matrigel has different effects on lymphocyte subpopulations. In agreement with the results on proliferation, matrigel also inhibits the production of IL-2 by Con A-stimulated lymphocytes.


Regulation of basal tyrosine phosphorylation of the B cell antigen receptor complex by the protein tyrosine phosphatase, CD45.

Signal transduction via the B cell AgR complex has recently been shown to be dependent on the activation of one or more protein tyrosine kinases. Similarly, it has been found that signal transduction requires the expression of the protein tyrosine phosphatase CD45. Thus, transduction of a signal after AgR cross-linking must involve the coordinate interaction of these two enzymatic activities. It is therefore logical to hypothesize that the competence of the B cell to respond to ligands that bind the AgR may be dependent on the maintenance of an equilibrium between the tyrosine phosphorylation and dephosphorylation of specific signal transduction components. We have demonstrated in the present study that in resting B cells, the basal level of AgR complex tyrosine phosphorylation is regulated by cellular protein tyrosine phosphatases. Treatment of cells with the protein tyrosine phosphatase inhibitor, Na3VO4, resulted in rapid hyperphosphorylation of the receptor complex. Based on this observation, experiments were designed to examine the role of CD45 in regulation of AgR complex phosphorylation. Treatment of B cells with anti-CD45 mAb alone was found to have no effect on cytoskeletal association of CD45 or on its distribution within the membrane. Addition of a secondary cross-linking reagent, however, induced the association of CD45 with the cytoskeleton and caused capping. Subsequent studies demonstrated that increased tyrosine phosphorylation of the mIg-associated proteins MB-1 and B29 could be induced after incubating cells with anti-CD45 mAb and a secondary cross-linker, but not after the addition of anti-CD45 mAb alone. Changes in tyrosine phosphorylation of MB-1 and B29 were found to correlate with the cytoskeletal association of CD45. Interestingly, although cross-linking CD45 induced alterations in its association with the cytoskeleton and in its distribution within the membrane, no significant change in the level of protein tyrosine phosphatase activity could be detected under these conditions. These findings support the possibility that ligand binding to CD45 can induce biochemical and/or physical alterations in the molecule that presumably inhibit its ability to interact with specific substrates in the cell, thereby shifting the established equilibrium between tyrosine-specific phosphorylation and dephosphorylation.


Unidirectional, heterologous desensitization of the pertussis toxin receptor by the CD3/TCR complex.

Prolonged exposure of many types of receptors to their cognate agonists can lead to a progressive lack of responsiveness. When this occurs after stimulation by the primary agonist for a given receptor it is termed homologous desensitization, and heterologous desensitization when to an agonist binding to a different type of receptor. Pertussis toxin (PTx) is a potent mitogen for human T lymphocytes. We have previously identified the human T cell PTx receptor (PTx-R) as a 43-kDa plasma membrane protein that, when stimulated, leads to the production of the intracellular second messengers, inositol-1,4,5-triphosphate, 1,2-sn-diacylglycerol, and elevated cytosolic calcium. The PTx-R appears to require the co-expression of the CD3/TCR complex because mutant cells that lack the AgR, but express the PTx-R, fail to respond to PTx. In this report, we have investigated the relationship between these two receptor systems. Activation of the PTx-R with submaximal concentrations of PTx did not affect the ability of an anti-CD3 antibody combined with rabbit anti-mIg to stimulate increases in intracellular free calcium concentration [Ca2+]i or diacylglycerol in human peripheral blood T cells. However, treatment with soluble anti-CD3 mAb, which lead to only a modest increase in [Ca2+]i, completely inhibited the effect of PTx. The cells were not refractory to further stimulation of the AgR because cross-linking with rabbit anti-mIg resulted in the standard maximal stimulation. This effect could be observed within 1 min of treatment with anti-CD3 mAb, and persisted for at least 1 h. The effect was not caused by production of either diacylglycerol (leading to activation of PK-C) or an increase in [Ca2+]i by anti-CD3 mAb because the effect could not be mimicked by either phorbol esters or a calcium ionophore. Pretreatment of either resting T lymphoblasts or PBL with anti-CD3 mAb also prevented enhanced [3H]TdR incorporation stimulated by PTx. These observations suggest a model in which T cells can regulate amplification of a non-AgR stimulatory pathway by heterologous desensitization.


Peripheral T cell receptor gamma delta variable gene repertoire maps to the T cell receptor loci and is influenced by positive selection.

Although the mechanisms that determine TCR-alpha beta V gene repertoire are well studied, the genetic influences involved in TCR-gamma delta repertoire development are unclear. Unlike the TCR-gamma delta populations that localize in epithelial tissues, the circulating peripheral TCR-gamma delta V region repertoire is quite diverse. Previous studies have shown that three TCR-gamma chains and at least six TCR-V delta genes are expressed by splenic TCR-gamma delta cells. However, the relative frequency of individual gamma delta subsets among genetically diverse mice has not been determined. Therefore, the repertoire of TCR-gamma delta cells was examined using anti-TCR V region specific mAb against V gamma 2 and V delta 4 on TCR-gamma delta + cells from total splenocytes. We found that there was a strain-specific variation in TCR-gamma delta usage. The frequency of V gamma 2 expression in different strains varied from 54 to 12%, and the frequency of V delta 4 expression in different strains varied from 38 to 10%. However, the level of V delta 4 and V gamma 2 expression for an individual strain was highly consistent from experiment to experiment. F1 analysis between parental strains that differed in relative frequency of either V gamma 2+ or V delta 4+ cells revealed that high expression was genetically dominant, suggesting that positive selection events play a major role in the peripheral gamma delta repertoire. Variations in the levels of V gamma 2+ cells and V delta 4+ cells was not associated with Mls or MHC haplotype. Analysis of recombinant inbred strains revealed that high V delta 4 expression mapped to the TCR-gamma locus, while high V gamma 2 expression was influenced by the TCR-delta locus. Back-cross analysis confirmed that the TCR loci dominantly influenced the level of V delta 4+ cells and V gamma 2+ cells; however, there was clear evidence that multiple genes affect the TCR-gamma delta repertoire.


The C/EBP family of transcriptional activators is functionally important for Ig VH promoter activity in vivo and in vitro.

We have examined the functional importance of binding sites for C/EBP family members (E sites), in two Ig VH promoters: VH1, a member of the S107 family, and BCL1, a member of the J558 family. Mutation of the E site in the VH1 promoter diminishes transcription in vivo to 59% of wild-type and transcription from the BCL1 promoter in vitro is inhibited to an average of 39% of wild-type by competition with E site oligonucleotides. Purified E site binding proteins from plasmacytoma cells stimulated BCL1 transcription in vitro 2.3-fold. Although five C/EBP family proteins are known which bind the E site, antibody ablation of DNA:protein complexes resolved by electrophoretic mobility shift assays showed that Ig/EBP-1 is the only E site binding protein detectable in early B cell lines; more mature B cells contain Ig/EBP-1 and NF-IL6. We also show by antibody-depletion that Ig/EBP-1 activates the BCL1 promoter in vitro.


EBV/C3d receptor (CR2) interacts by its intracytoplasmic carboxy-terminal domain and two distinct binding sites with the p53 anti-oncoprotein and the p68 calcium-binding protein.

EBV/C3d receptor (CR2) interacts with the p53 anti-oncoprotein expressed in the human B lymphoma cells, Raji but not in normal B cells, and with the p68 calcium-binding protein, expressed in normal B lymphocytes but not in transformed B lymphocytes. To characterize the CR2 domain interacting with these two intracellular proteins, we synthesized a 34-amino acid peptide, pep34, corresponding to its intracytoplasmic carboxy-terminal domain and analyzed its binding and antigenic properties. Binding of 125I-labeled p53 or 125I-labeled p68 on immobilized pep34 was specific, additive, and totally inhibited by unlabeled p53 or p68, respectively, but not by unlabeled p68 or p53, respectively. Antigenic properties of pep34 were analyzed by immunizing rabbits with particle-bound pep34. Polyclonal anti-pep34 Ab carried anti-CR2 specificities that recognized only the intracellular domain of CR2. In addition, anti-pep34 Ab also carried anti-p53 or anti-p68 specificities. Anti-p53 or anti-p68 specificities were not due to putative common structural or conformational antigenic determinants between the pep34 synthetic peptide and the p68 or p53 proteins. These anti-p53 and anti-p68 specificities were identified as anti-idiotypic anti-CR2 Ab mimicking either p53 or p68 binding sites of CR2. These data clearly establish that despite its short length, the intracytoplasmic C-terminal tail of CR2 is involved in direct protein-protein interactions with the two intracellular regulatory proteins, p53 and p68. An additional feature of these data is the demonstration that particle-bound pep34 triggered "in vivo" anti-Id Ab restricted to either p53 or p68 specificities.


A DNase I-hypersensitive site in the second intron of the murine IL-4 gene defines a mast cell-specific enhancer.

IL-4 is a potent immunoregulatory cytokine that exhibits extremely diverse effects on a number of target cells. Although IL-4 was originally described as a T cell-derived product, it is evident that cells of the basophil/mast cell lineage are also an important source of this cytokine. Based on their different tissue distribution, mast cell and T cell-derived IL-4 may have distinct effects on local immune responses. The physiologic production of IL-4 appears to be tightly regulated because most T and mast cells require activation to express significant levels of IL-4. In contrast, a majority of murine transformed mast cell lines constitutively express relatively high levels of IL-4. In this study, transformed mast cell lines were used as models to define cis acting sequences that regulate mast cell IL-4 transcription. Chloramphenicol acetyltransferase reporter gene constructs containing 6.3 kb of 5' IL-4 flanking sequence direct relatively low chloramphenicol acetyltransferase expression in these cells. These results indicated that additional sequences may be important in stimulating transcriptional activity of the IL-4 gene. Using DNAse I hypersensitive site analysis to define other potential IL-4 transcriptional regulatory regions, two sites were identified in the murine IL-4 gene that appear to be unique to IL-4 expressing transformed mast cells. One site defines an intronic sequence that exhibits prototypic enhancer activity in several independently derived transformed mast cell lines. This enhancer is also active in stimulated, non-transformed mast cells but not stimulated EL-4 T cells. Taken together, these data indicate that the IL-4 intronic sequence contains a mast cell specific enhancer that plays an essential role in the unregulated expression of IL-4 in transformed mast cells and may also be important in the inducible expression of IL-4 in normal mast cells.


Molecular cloning of the murine IL-1 beta converting enzyme cDNA.

IL-1 beta is a potent modulator of immune and inflammatory responses. Murine IL-1 beta is initially synthesized as an inactive 33-kDa pro-molecule that is activated by proteolytic cleavage between Asp-117 and Val-118 to generate the 17-kDa mature IL-1 beta protein. This cleavage is catalyzed by a specific protease that has been designated the IL-1 beta converting enzyme (or IL-1 beta convertase). We have used a human IL-1 beta convertase cDNA to isolate murine convertase cDNA from a WEHI-3 library. These cDNA predicted that the murine convertase is a 402-residue protein. Overall, the murine convertase showed 71% nucleotide and 62% predicted amino acid sequence identity with the human convertase. Southern blot analysis of interspecific backcross mice indicated that the murine IL-1 beta convertase is encoded by a single copy gene located on murine chromosome 9. The murine convertase showed broad constitutive expression, being detected in mononuclear phagocyte and T lymphocyte cell lines as well as in spleen, heart, brain, and adrenal glands. The expression of the murine convertase in mononuclear phagocytes was up-regulated by treatment with LPS or rIFN-gamma. These studies establish that the IL-1 beta convertase is an evolutionarily conserved, widely expressed enzyme that can be regulated at a pretranslational level.


Patterns of antibody specificity during the BALB/c immune response to hen eggwhite lysozyme.

We tested 49 BALB/c antilysozyme mAb from seven intervals during the immune response to lysozyme for patterns of specificity and avidity. We found that the antibody epitopes in composite covered at least 80% of the lysozyme surface, and their patterns of overlap suggest a continuum of potential antibody epitopes. Previously observed regional specificities, which emerged at different times in the immune response, were more discretely defined in late response antibodies, when the majority of mAb could be assigned to one of three functionally nonoverlapping complementation groups. The area covered by each antigenic region may be greater than an individual epitope, and may include multiple epitopes that overlap structurally and functionally to varying degrees. Connectivity between antigenic regions was seen in interactions among early and late stage antibodies, and among secondary stage mAb, but not among tertiary stage mAb from hyperimmunized mice. Patterns of overlap of early and late response antibodies suggest that the organization of antibody specificities change during the progression from primary to secondary to tertiary response. Over the same period in the response, the average relative avidity of IgG1 kappa mAb did not increase, suggesting that "affinity maturation" of serum antibodies reflects an increase in the number and diversity of antibodies, rather than an overall increase in the avidity of individual antibodies.


Molecular characterization of the WC1 antigen expressed specifically on bovine CD4-CD8- gamma delta T lymphocytes.

Although gamma delta T lymphocytes were identified several years ago, the functional importance of these cells remains to be established. gamma delta T cells of ruminants are unique in two respects. First, they are present at much higher levels compared to man and rodents. Second, ruminant CD4-CD8- gamma delta T cells uniquely express a 220 kD surface Ag recognized by a panel of mAb, recently clustered as WC1. WC1 has been most extensively studied in sheep with the use of the mAb T19. Here, we report on the isolation of a full length cDNA clone, encoding the WC1 Ag, from a COS cell cDNA expression library prepared from a bovine gamma delta T cell line. The protein encoded by the pWC1 cDNA clone was reactive with the bovine mAb CC15 and IL.A29, and with T19. The cDNA clone consisted of 4475 bp and contained a single long open reading frame of 1436 amino acids. The pWC1 cDNA clone encoded a type 1 integral membrane protein with an extracellular domain consisting of 11 scavenger receptor cysteine-rich-repeats with homology to CD5 and CD6. Southern blotting suggested that the bovine genome contained multiple sequences highly related to the isolated WC1 cDNA. Furthermore, WC1-like sequences were present in the genomes of all mammals tested including mouse and man. The molecular characterization of the WC1 Ag as reported here provides a starting point for the definition of its role in gamma delta T cell biology.


Tumor necrosis factor-alpha-dependent production of reactive nitrogen intermediates mediates IFN-gamma plus IL-2-induced murine macrophage tumoricidal activity.

We have previously established that IFN-gamma plus IL-2 induces murine macrophage tumoricidal activity. The purpose of this study was to identify the effector molecules that account for the IFN-gamma plus IL-2-induced macrophage cytotoxicity against P815 mastocytoma cells. ANA-1 macrophages and normal thioglycollate-elicited mouse peritoneal macrophages produced little or no detectable nitrite (NO2-) after incubation with IFN-gamma alone or IL-2 alone; however, IL-2 synergized with IFN-gamma for the production of NO2-. IFN-gamma plus IL-2 did not induce NO2- production or tumoricidal activity in ANA-1 macrophages that were cultured in medium devoid of L-arginine or in ANA-1 macrophages that were incubated with NG-monomethyl-L-arginine. As observed previously with ANA-1 macrophage tumoricidal activity, IL-4 inhibited IFN-gamma plus IL-2-induced, but not IFN-gamma plus LPS-induced, NO2- production. IL-4 also selectively decreased the ability of IFN-gamma and/or IL-2 to augment TNF-alpha mRNA expression in ANA-1 macrophages. Lastly, incubation of ANA-1 macrophages with anti-TNF mAb selectively inhibited the ability of IFN-gamma plus IL-2 to induce NO2- production and tumoricidal activity. These results indicate that IFN-gamma plus IL-2-induced tumoricidal activity is dependent upon the metabolism of L-arginine to reactive nitrogen intermediates, and they establish a role for TNF-alpha as a required intermediate for IL-2-dependent NO2- production and tumoricidal activity.


Retinoic acids inhibit activation-induced apoptosis in T cell hybridomas and thymocytes.

Apoptosis is induced in immature thymocytes and T cell hybridomas upon stimulation via the TCR/CD3 complex. This phenomenon appears to be related to negative selection of T cell clones in the thymus. In T cell hybridomas, it has been shown that glucocorticoids inhibit TCR/CD3-mediated apoptosis, whereas glucocorticoids alone induce apoptosis. All-trans-retinoic acid (RA) at 0.1 to 10 microM also inhibited TCR/CD3-mediated apoptosis assessed by DNA fragmentation and cytolysis, but RA alone hardly induced apoptosis. RA enhanced the effects of glucocorticoids to induce apoptosis and to inhibit TCR/CD3-mediated apoptosis. TCR/CD3-mediated stimulation can be mimicked by the combination of ionomycin, a calcium ionophore, and PMA, an activator of protein kinase C, and the combination-induced DNA fragmentation was also inhibited by RA. RA, however, failed to inhibit the combination-induced increase in intracellular Ca2+ concentration or the combination-induced translocation of protein kinase C from the cytosolic fraction to the particulate fraction. Time course studies of RA addition into the culture indicated that a 3- to 6-h delay in the addition of RA did not reduce its inhibitory effect on anti-CD3-induced DNA fragmentation. These results suggest that RA interferes with the apoptotic process at some point after its initiation stage. It has been suggested that negative selection involves not only TCR/CD3-mediated signals but also LFA-1-mediated signals. RA at 0.01 to 1 microM significantly inhibited the induction of thymocyte apoptosis by co-immobilized mAb to CD3 and LFA-1 molecules. RA by itself hardly induced apoptosis, but enhanced glucocorticoid-induced apoptosis. The results suggest that thymic selection might be influenced by RA at near-physiologic concentrations. The receptors of glucocorticoids and RA belong to the erbA oncogene-related steroid hormone receptor superfamily. Thyroid hormones and 1 alpha,25-dihydroxy vitamin D3, whose receptors also belong to the superfamily, failed to modulate apoptosis in both T cell hybridomas and thymocytes.


Role of IL-6, IL-2, and IL-4 in the in vitro induction of cytotoxic T cells.

The mode of IL-6-induced differentiation of Con A-stimulated CD4-CD8+ CTL-P was examined. Through application of neutralizing anti-IL-6, anti-IL-2, and anti-IL-4 mAb it was shown that IL-6 is an "early acting" factor for development of accessory cell-depleted thymocytes. IL-2 and IL-4 are obligatory "late acting" factors for this process. In accordance IL-4, but not IL-6, induced active CTL from CD4-CD8+ CTL-P. The increase of CD4-CD8+ CTL originates at least partially from CD4+CD8+ cells differentiating to active CTL in vitro. CTL development was paralleled by an increase in CD4-CD8+ cells and by a distinct increase in [3H]TdR uptake on day 2 of cultivation. Our data suggest that IL-6 induces Th cells to produce IL-2 and IL-4, the mediators for final differentiation of CD4-CD8+ cells.


Antibodies and reactive T cells against the malaria heat-shock protein Pf72/Hsp70-1 and derived peptides in individuals continuously exposed to Plasmodium falciparum.

Pf72/Hsp70-1, a heat-shock protein of m.w. 72 kDa from Plasmodium falciparum is one of the Ag of interest to be included in a polyvalent vaccine against malaria. It is one of the major immunogens present in a fraction of purified blood stage parasites that elicited protection against experimental infection of Saimiri monkeys with blood stages of P. falciparum. It is present at all blood stages and one of its B cell epitopes is also detected on the surface of the infected hepatocyte. Moreover, Pf72 appears to be well conserved among different isolates of P. falciparum. We have examined the immune response against Pf72/Hsp70-1 in individuals from different age groups living in a holoendemic area (West Africa). The immune response against the native Ag (purified from schizonts and called Pf/Hsp70) was analyzed both at the humoral level by ELISA and at the cellular level by assessing in vitro proliferation and IFN-gamma production of PBMC. Of the individuals studied 52% had a statistically significant level of anti-Pf/Hsp70 antibodies as compared with unexposed individuals. These positive individuals showed a heterogeneous distribution because significant levels of antibodies were found in 70% of the adults but in only 26% of the children. The presence of Pf/Hsp70-specific reactive T cells in the blood was detected in 32% of the individuals. The total anti-Pf/Hsp70 antibody level (IgG+IgM) appeared strongly age related and correlated positively with parasite exposure, whereas the T cell response failed to correlate either with the antibody level or with age. Moreover, PBMC of donors responded to the Pf/Hsp70 in a dissociated way, namely, by either T cell proliferation or IFN-gamma production. Ten synthetic peptides based on sequences found in the C-terminal part of Pf72/Hsp70-1 were further tested as potential T cell epitopes. The proliferative response of PBMC from individuals continuously exposed to the parasite showed that three peptides more frequently trigger significant T cell proliferation (in 21% to 27% of the individuals) and three others less frequently (10%). None of these peptides allowed detection of reactive T cells in PBMC of Europeans with no previous exposure to malaria. Some of the stimulating peptides are highly similar to human heat-shock Hsc and Hsp70 with large stretches of identical amino acids.(ABSTRACT TRUNCATED AT 400 WORDS)


Selective expression of a major allergen and cytotoxin, Asp f I, in Aspergillus fumigatus. Implications for the immunopathogenesis of Aspergillus-related diseases.

Asp f I is a major 18-kDa Aspergillus fumigatus allergen and a member of the mitogillin family of cytotoxins. The nucleotide sequence of the Asp f I gene was determined by sequencing polymerase chain reaction products amplified from A. fumigatus spore DNA. The entire 678-bp DNA includes an 81-bp leader sequence, preceding the N-terminal alanine codon, a 52-bp intron, and a 444-bp open reading frame, encoding a 149-amino acid protein (M(r) 16,899), which is 99% homologous to mitogillin from Aspergillus restrictus. A mAb-based ELISA was used to compare Asp f I levels in spores, mycelia, and culture filtrate, and to determine the kinetics of allergen production. Disrupted hyphae or spore extracts had a 1000-fold lower level of Asp f I than culture filtrate, suggesting that germination of spores and growth of the fungus are essential for allergen production. Asp f I levels in A. fumigatus and A. restrictus peaked at day 3 (0.87 to 12.1 micrograms/ml), however, the allergen was not detected in Aspergillus flavus, Aspergillus niger, Aspergillus terreus, and Aspergillus nidulans cultures (< 1.5 ng/ml) on either days 3 or 8. Northern analysis confirmed that Asp f I mRNA was detected only in A. fumigatus and A. restrictus, but not in the other four Aspergillus spp. Asp f I-specific DNA was generated after polymerase chain reaction amplification of genomic mycelial DNA obtained from A. fumigatus and A. restrictus, but not from the other Aspergillus spp. The results show that Asp f I is selectively expressed in A. fumigatus, and suggest that this cytotoxin could be a specific virulence factor for A. fumigatus.


Role of P2z purinergic receptors in ATP-mediated killing of tumor necrosis factor (TNF)-sensitive and TNF-resistant L929 fibroblasts.

Two closely related cell lines were characterized in their responses to extracellular ATP (ATPo): the fibroblast cell line L929 and a TNF-resistant variant L929/R. Both lines showed ATPo-activated increases in intracellular Ca2+, inward current, and sustained depolarization of the plasma membrane, cell responses compatible with activation of purinergic receptors of the P2y, P2x, or P2z subtype; however, only the L929/R variant was susceptible to ATPo-dependent early permeabilization of the plasma membrane to hydrophilic solutes of M(r) below 900, a response uniquely caused by the activation of P2z receptors. Both cell types were susceptible to the cytotoxic effect of ATPo, but killing of the L929/R variant required much shorter incubations in the presence of this nucleotide. Morphologic examination of ATPo-challenged L929 and L929/R cells showed that cell death occurred by two alternative mechanisms: colloido-osmotic lysis or apoptosis. Occurrence of apoptosis was confirmed by agarose gel analysis of cellular DNA. Although ATPo caused a fast mobilization of intracellular Ca2+, neither colloido-osmotic lysis nor apoptosis were Ca2+ dependent. Our results show that the L929/R variant, but not the L929 parental fibroblast cell line, expresses functional purinergic receptors of the P2z subtype. The presence of P2z receptors confers to L929/R cells enhanced susceptibility to ATPo-mediated cytotoxicity.


Release of granulocyte-macrophage colony-stimulating factor by alveolar macrophages in the lung of HIV-1-infected patients. A mechanism accounting for macrophage and neutrophil accumulation.

In this paper, the release of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the lung of patients with HIV-1 infection was evaluated. This cytokine has well recognized effects on granulocyte and macrophage growth and differentiation and plays some role in the mechanisms leading to the accumulation of alveolar macrophages (AM) in patients with interstitial lung disease. Detectable levels of GM-CSF (up to 10 pg/ml) were demonstrated in unconcentrated bronchoalveolar lavage fluid retrieved from HIV-1-seropositive patients, thus suggesting that the GM-CSF is released in vivo in the lung during HIV-1 infection. A statistically significant correlation was demonstrated between the bronchoalveolar lavage concentrations of GM-CSF and the absolute numbers of AM and lung neutrophils. Cell-free supernatants obtained from unstimulated 24-h cultured AM isolated from HIV-1-infected patients contained discrete amounts of GM-CSF, as demonstrated by an immunoenzymatic assay. AM lost the capability of releasing GM-CSF after 72 h of culture, thus suggesting that the production of GM-CSF is not constitutive in AM. After exposition of AM with LPS, the release of GM-CSF and the expression of its mRNA significantly increased with respect to the baseline values; interestingly, the amount of GM-CSF released by LPS-stimulated AM was more than 10-fold higher in HIV-1-infected patients than in healthy subjects. As demonstrated by flow cytometry analysis, more than 70% of freshly isolated AM efficiently bound phycoerythrin-GM-CSF, thus indicating that they express the receptor for GM-CSF. Determination of AM in G1, S, and G2+M by flow cytometry showed that, after 48 h of culture with GM-CSF, 5.5 to 7% of AM entered the proliferative phase of the cell cycle. Taken together, these findings suggest that AM might represent an important source of GM-CSF production in HIV-1 infection. In particular, the hypothesis is formulated that pulmonary opportunists might trigger AM to synthesize GM-CSF in situ. The local overproduction of this cytokine is likely to play a role in the pathogenic events leading to the local proliferation of AM and recruitment of neutrophils in AIDS-associated interstitial lung disease.


Redox status of cells influences constitutive or induced NF-kappa B translocation and HIV long terminal repeat activity in human T and monocytic cell lines.

We have tested the hypothesis that cellular activation events occurring in T lymphocytes and monocytes and mediated through translocation of the transcription factor NF-kappa B are dependent upon the constitutive redox status of these cells. We used phenolic, lipid-soluble, chain-breaking antioxidants (butylated hydroxyanisole (BHA), nordihydroquairetic acid, or alpha-tocopherol (vitamin E) to show that peroxyl radical scavenging in unstimulated and PMA- or TNF-stimulated cells blocks the functions depending on NF-kappa B activation. BHA was found to suppress not only PMA- or TNF-induced, but also constitutive, HIV-enhancer activity concomitant to an inhibition of NF-kappa B binding activity in both lymphoblastoid T (J.Jhan) and monocytic (U937) cell lines. This was also true for KBF (p50 homodimer) binding activity in U937 cells. Secretion of TNF, the product of another NF-kappa B-dependent gene, was abolished by BHA in PMA-stimulated U937 cells. The anti-oxidative effect of BHA was accompanied by an increase in thiol, but not glutathione, content in stimulated and unstimulated T cell, whereas TNF stimulation itself barely modified the cellular thiol level. Oxidative stress obtained by the addition of H2O2 to the culture medium of J.Jhan or U937 cells could not by itself induce NF-kappa B activation. These observations suggest that TNF and PMA do not lead to NF-kappa B activation through induction of changes in the cell redox status. Rather, TNF and PMA can exert their effect only if cells are in an appropriate redox status, because prior modification toward reduction with BHA treatment prevents this activation. It appears that a basal redox equilibrium tending toward oxidation is a prerequisite for full activation of transduction pathways regulating the activity of NF-kappa B-dependent genes.


A combined immunodeficiency with oligoclonal CD8+, V beta 3-expressing, cytotoxic T lymphocytes in the peripheral blood.

The diagnosis severe combined immunodeficiency was made in a male infant at the age of 18 wk. Known causes of severe combined immunodeficiency were excluded. The activity of total 5'-nucleotidase (E.C. 3.1.3.5) in the PBMC was found to be strongly decreased. Analysis of the peripheral blood revealed a lymphocytosis, mainly of CD8+ T cells. These lymphocytes expressed high levels of CD29, CD38, CD45RA, and MHC class II molecules but no CD25, CD26, CD27, or CD28 Ag. The cells proliferated poorly to all T cell stimulants tested and no helper activity for IgM secretion could be induced. In contrast to the poor proliferative responses, high levels of TCR-induced cytolytic activity, without lymphokine-activated killer-cell outgrowth, were induced by CD3 mAb. Analysis of TCR-beta gene rearrangements indicated that two clonal populations constituted the majority of the E-rosette+ peripheral blood fraction. Moreover, the vast majority of the CD8+ cells were found to react with a mAb to V beta 3. Polymerase chain reaction on cDNA from peripheral blood cells with primers that amplify TCR V beta elements showed, in agreement with the fluorescence data, an overrepresentation of V beta 3 but absence of usage of approximately 50% of the other V beta elements. Thus, in a severe combined immunodeficiency patient, CD8+ T cells with limited T cell receptor usage and restricted effector functions were found. The observed alterations in the 5'-nucleotidase levels may be secondary to the outgrowth of this population.


Distinctive HLA-A,B antigens of black populations formed by interallelic conversion.

Alleles encoding five HLA-A and B Ag characteristic of black populations have been isolated and their nucleotide sequences determined. In each case, the "black" allele is similar to a "related" allele found in caucasoid populations. The primary differences between these pairs of alleles are localized clusters of nucleotide substitutions that change two to five residues of the Ag recognition site. The pattern of differences indicates that the pairs of black and caucasoid alleles diverged primarily as a result of interallelic conversion events.


Idiotypic and antiidiotypic T and B lymphocytes in myasthenia gravis.

The prevalence of Id and anti-Id T and B cells as measured by their reactivities with two human mAb, one antiacetylcholine receptor mAb and one anti-Id mAb, was studied in 38 patients with myasthenia gravis and in 27 healthy individuals. Id and anti-Id T cells were estimated by enumerating the numbers of cells secreting IFN-gamma in response to 10 pg/ml of the human mAb. T cell stimulation, measured as numbers of IFN-gamma-secreting cells that exceeded the mean + 2 SD of controls, was induced by the Id mAb in 78.9% of the patients and in 7.4% of the controls, whereas the anti-Id mAb-stimulated T cells in 55.3% of the patients and in 3.7% of the controls. The mean value of the Id and anti-Id-reactive T cells in the patients was 18.3/10(5) and 10.1/10(5) PBMC, respectively. B cells secreting IgM antibodies binding to the human mAb were increased in patients with myasthenia gravis compared to healthy controls. Seventy-five percent of the patients and 12% of the controls had B cells secreting IgM antibodies binding to the Id mAb, although 89% of the patients and 16% of the controls had B cells secreting IgM antibodies binding to the anti-Id mAb. The mean value of B cells secreting IgM antibodies binding to Id or anti-Id mAb in the patients were 7.4 cells/10(6) and 5.5 cells/10(6) PBMC, respectively. We conclude that Id and anti-Id T and B cells are present in myasthenia gravis. These methods allow a quantitative estimation of T and B cells with defined specificities and thus a way of mapping the repertoire of lymphocytes.


Freshly isolated, murine neonatal T cells produce IL-4 in response to anti-CD3 stimulation.

In previous studies of chimeric animals, we found that fetal intrathymic T cell precursors give rise to phenotypically abnormal peripheral T cell populations. Because most peripheral T lymphocytes in newborn mice are the progeny of fetal T cell precursors, this result led to the hypothesis that neonatal and adult T cells differ in their functional capacities. To investigate this issue, the responses of neonatal and adult T cells to anti-CD3 antibody and TCR-independent stimulation were compared. When stimulated with soluble anti-CD3 antibody in the presence of adult accessory cells, neonatal T cell proliferation was markedly decreased compared with that of adult T cells. This reduction in proliferation was associated with both quantitative and qualitative differences in lymphokine production. At 48 h of stimulation with anti-CD3 antibody, neonatal T cells produced at least 10-fold less IL-2 than adult T cells. This apparently accounted for their reduced proliferation because the addition of exogenous IL-2 restored their proliferation to the levels achieved by adult T cells. In striking contrast to adult T cells, neonatal T cells secreted large amounts of IL-4 upon primary stimulation in vitro. The differences between neonatal and adult T cells in proliferation and lymphokine production were shown to be specific for CD3-mediated stimulation. In the presence of phorbol ester and calcium ionophore, neonatal and adult T cells showed equivalent proliferation and IL-2 production. Under these conditions, IL-4 production by neonatal or adult T cells was essentially undetectable. Thus, in response to TCR-independent stimulation, freshly isolated neonatal and adult T cells show similar functional responses. However, when stimulation occurs via the CD3 components of the TCR, the responses of neonatal T cells resemble those of primed T cells from adult animals.


Enhanced antigen presentation using human Fc gamma receptor (monocyte/macrophage)-specific immunogens.

A major new challenge for vaccine development is to target APC such as monocytes and macrophages for efficient Ag processing and presentation. It has been shown that Fc gamma R-mediated uptake of Ag-antibody complexes can enhance Ag presentation by myeloid cells at least 100-fold, and directing Ag to Fc gamma R in mice brings about a substantial increase in the effectiveness of immunization while eliminating the requirement for adjuvant. It has not been determined which of the three subclasses of human Fc gamma R on myeloid cells (Fc gamma RI, Fc gamma RII, or Fc gamma RIII) function to enhance Ag presentation. We have targeted our Ag (TT) to each of the three subclasses of human Fc gamma R on monocytes using Fc gamma R subclass-specific mAb-TT conjugates, and have measured TT presentation by monitoring T cell proliferation in response to TT. In addition, we have examined enhanced Ag presentation mediated by a human IgG1 (HIgG1) anti-TT mAb. All anti-Fc gamma R-TT conjugates enhanced Ag presentation. HIgG1 anti-TT, in monomeric form, enhanced Ag presentation through Fc gamma RI only. Anti-Fc gamma RI-Ag conjugates appear to be optimal for application as vaccines. They are monocyte/macrophage-specific, are very efficiently processed and presented, and enhance Ag presentation despite occupation of Fc gamma RI with HIgG.


Evidence for a role for T cell receptors (TCR) in the effector phase of acute bone marrow graft rejection. TCR V beta 5 transgenic mice lack effector cells able to cause graft rejection.

Lethally irradiated mice reject within 24 h certain marrow grafts, a phenomenon called either allogeneic or hybrid resistance. The cells responsible for this rejection (NK1+ CD3+ cells (TNK) express Ag of NK cells as well as the TCR-associated CD3 complex. This raises the question whether TCR participate in the function of these cells during graft rejection. By using flow cytometry it is shown that the majority of TNK cells expresses the TCR-alpha/beta chains and by using adoptive cell transfer assays evidence is presented that it is the TCR-alpha/beta expressing cells that cause rejection. To explore whether any particular TCR chains have to be expressed on these cells, C57L mice were assayed and found to be responders suggesting that the V beta chains deleted in these mice are not obligatory. However, introduction of a specific TCR V beta 5 chain into C57BL/6 mice as a transgene leads to inability to transfer resistance. TNK cells of V beta 5 transgenic mice express the introduced gene suggesting that it is the transgenic TCR that is responsible for the lack of function. In assessing T cell functions in V beta 5 transgenic mice it is shown that although these mice generate CTL specific for H-2d targets there is a deficiency to recognize H-2Dd, i.e., of determinants presumed to be recognized in the acute rejection mechanism. Thus TNK cells and CTL share the inability to recognize H-2Dd epitopes due to expression of the V beta 5 transgene. The notion that TCR on TNK cells play a role in the acute rejection process makes it necessary to postulate a receptor selection mechanism for these cells.


Gamma delta T cells assist alpha beta T cells in adoptive transfer of contact sensitivity.

Cutaneous immune responses to contact sensitizers such as picryl chloride or oxazolone, are classical manifestations of T cell-mediated immunity in vivo. In fact, the first documentation of T cell-mediated immunity was the ability to adoptively transfer contact sensitivity (CS) responses. Although it is now clear that Ag/MHC-restricted alpha beta TCR positive effector T cells are responsible for 24 to 48 h CS responses, other subsets of Thy-1+ cells in mice also participate in the elicitation of CS. Thus, Thy-1+, CD5+, CD3-, B220+, hapten-specific, non-MHC-restricted early-acting cells are required to initiate CS responses by leading to local serotonin release, which allows for extravascular recruitment of the late-acting, alpha beta TCR+, CS effector T cells. This study describes another T cell population that is needed for the adoptive transfer of CS by alpha beta T cells. In vitro treatment of a mixture of CS effector cells with hamster mAb to gamma delta TCR, together with rabbit complement, or by panning on anti-hamster Ig-coated dishes, diminished substantially the subsequent transfer of CS reactivity without affecting either CS-initiating cells, or the later-acting, alpha beta TCR+ CS effector T cells. Immune cells treated with anti-alpha beta TCR mAb, or recovered as adherent cells from petri dishes after anti-gamma delta TCR panning (i.e., gamma delta TCR-enriched cells), reconstituted the ability of anti-gamma delta TCR-treated immune cells (i.e., alpha beta TCR-enriched cells) to transfer 24-h CS responsiveness. The phenotype of the gamma delta T cells that assisted CS effector alpha beta T cells was: CD3+, CD4-, and CD8+. The gamma delta T cells that assisted alpha beta T cells were not Ag-specific since anti-alpha beta-TCR-treated cells (gamma delta T-enriched) from picryl chloride immunized donors aided alpha beta T cells (anti-gamma delta TCR-treated) from oxazolone-immunized donors, and conversely gamma delta T cells from oxazolone-immunized donors aided alpha beta T cells from picryl chloride immunized donors. Furthermore, the CS-regulating gamma delta T cells were not MHC-restricted because gamma delta T cells from H2d or H2b donors could assist alpha beta T cells from H2k donors. It was concluded that a regulatory population of non-Ag specific, non-MHC-restricted gamma delta T cells was needed to assist immune effector, Ag/MHC-specific alpha beta T cells in the adoptive transfer of CS.


Poly-(ADP-ribose) polymerase partially contributes to target cell death triggered by cytolytic T lymphocytes.

We hypothesized that CTL-induced target cell (TC) death is partially due to processes that follow the DNA damage in target cells and include the activation of poly-ADP-ribose transferase (PADPRT) by DNA strand breaks. According to this model, the activated PADPRT is expected to deplete NAD, ATP, and to contribute to the TC death. We used inhibitors of PADPRT and a PADPRT-deficient cell mutant, as well as other nucleated TC and SRBC to test the role of PADPRT in CTL-induced cytotoxicity. It is found that inhibitors of PADPRT (3-aminobenzamide, benzamide (aromatic amides)) and nicotinamide all inhibit the CTL-mediated lysis of both Ag-specific TC and of Ag-nonbearing TC. The effect of PADPRT inhibitors was not due to inhibition of the lethal hit delivery by CTL, because in parallel control experiments, the same inhibitors did not interfere with CTL-induced lysis of SRBC, cells that are devoid of nuclei and PADPRT. Moreover, the effect of inhibitors of PADPRT did not affect earlier stages of lethal hit delivery because 3-aminobenzamide and benzamide did not interfere with CTL-induced DNA fragmentation in TC at concentration which protected TC lysis. Importantly, a PADPRT-deficient cell line was also much more resistant to CTL-induced lysis as tested in retargeting (4 and 8 h) assays; this was expected if activation of PADPRT is indeed involved in TC death. Control experiments reveal that the relative resistance of the PADPRT-deficient cell mutant to CTL-induced lysis was not related to its impaired ability to form conjugates and to trigger CTL (as tested in granule exocytosis assay). In addition, PADPRT-deficient cells were as susceptible to CTL-induced DNA fragmentation as were the control cells; yet, they were resistant to CTL-induced 51Cr-release. Control cells and PADPRT-deficient mutant were equally susceptible to antibody+C'-mediated lysis. Our data support the view that the activation of PADPRT can contribute to the CTL-induced cytolysis of some TC, but is not involved in lysis of other TC, as evidenced by the ability of CTL to efficiently lyse SRBC. These data suggest that there could be multiple molecular pathways of TC death in CTL-mediated cytotoxicity and the relative contribution of PADPRT and/or other enzymes will reflect the individual make-up of a particular TC.


Expression of VLA-4 on thymocytes. Maturation stage-associated transition and its correlation with their capacity to adhere to thymic stromal cells.

The present study investigates the expression of VLA-4 on thymocytes at various stages of maturation and their capacity to adhere to thymic stromal cells. Whole thymocytes were stained with anti-CD4 and anti-CD8, as well as anti-VLA-4 antibodies. Flow microfluorometric analyses revealed that a) most of CD4-8- (double negative DN) and CD4-8intermediate thymocyte populations expressed large amounts of VLA-4, b) the levels of VLA-4 were considerably and markedly reduced on CD4+8+ (double positive DP) and single positive (SP) (CD4+8- or CD4-8+) populations, respectively. This contrasted with an increase in the levels of LFA-1 along with thymocyte maturation. DN, DP, and SP subsets were isolated and examined for their capacity to express VLA-4 and to adhere to fibronectin (FN) molecules as well as thymic stromal cells expressing FN. DN, DP, and SP subsets were confirmed to express the respective high, low, and very low levels of VLA-4, respectively. Approximately 70% of DN thymocytes became bound to FN-precoated culture plates, whereas 30 to 40% of DP and only 10 to 20% of SP cells adhered to FN. Similar patterns of adhesion were observed between these thymocyte subsets and thymic stromal monolayers. The binding of the DN subset to FN-plates or thymic stromal monolayers was inhibited only marginally by the RGDS peptide, but was efficiently inhibited by V10 peptide (cell-binding sequence that is located in the V region on FN and reacts with the VLA-4 integrin) or anti-VLA-4 antibody. Anti-VLA-4 antibody plus RGDS peptide strongly inhibited DN cell binding to FN-coated plates and thymic stromal monolayers. These results indicate that i) VLA-4 expressed on DN thymocytes functions as an important integrin for interacting with thymic stromal cells; ii) the expression level of this integrin decreases with the progress of thymocyte maturation, and iii) most of the mature thymocytes (SP) are rendered less adhesive to thymic stromal cells by reducing the level of VLA-4 expression.


Cytokine pattern of Langerhans cells isolated from murine epidermal cell cultures.

In the present study we demonstrate that supernatants of highly enriched cultured Langerhans cells (cLC) display IL-1, IL-6, granulocyte/macrophage (GM)-CSF, and TNF-alpha, but no IL-2, IL-3, IL-4, and IFN-gamma activities. We further show that IL-6, GM-CSF, and TNF-alpha bioactivities can be specifically blocked in the presence of the respective neutralizing mAb. Concerning the IL-1 bioactivity, the combined use of anti-IL-1 alpha and anti-IL-1 beta mAb was needed to completely inhibit the proliferative response of the indicator cell line D10. One of the difficulties in studying the secretory potential of LC is that even highly enriched cLC are contaminated with keratinocytes (KC), which are known to be a rich source of cytokines. To overcome this problem we compared cytokine bioactivities in supernatants of cell cultures consisting of selected cLC:cKC ratios. These cell mixing experiments revealed that cLC are the major source of the IL-6 bioactivity, whereas IL-1, GM-CSF, and TNF-alpha are predominantly generated by cKC. In order to determine whether the cytokine bioactivities measured in supernatants of epidermal cell cultures are simply caused by an increased release or by de novo synthesis, we performed molecular biologic studies. Polymerase chain reaction analysis of cLC and cKC revealed that IL-1 beta and IL-6 transcripts are virtually limited to cLC, whereas IL-1 alpha, GM-CSF, and TNF-alpha messages are preferentially exhibited by cKC. mRNA coding for IL-2, IL-3, IL-4, and IFN-gamma could neither be amplified from cLC nor from cKC. Furthermore, the quantitative comparison of cytokine transcripts in cLC vs cKC using Northern blot analysis and mRNA detection on the single cell level using in situ hybridization confirmed that cLC generate IL-6, whereas cKC synthesize IL-1 alpha and GM-CSF. Taken together our results demonstrate that cultured murine LC synthesize and secrete IL-1 beta and IL-6, cytokines known to be important accessory molecules in T cell activation.


The presence in a mouse T cell line of a 97-kDa protein kinase C (PKC) with characteristics similar to known members of the novel PKC subgroup and its possible role in lymphocyte gene expression.

The receptor for tumor-promoting phorbol esters has been shown to be the Ca+2/phospholipid dependent enzyme protein kinase C (PKC). There are two major groups of PKC, the conventional PKC isotypes alpha, beta I, beta II, gamma) and the novel Ca+2-independent PKC (delta, epsilon, zeta, eta). Phorbol esters previously have been demonstrated to increase human IFN-gamma gene expression after treatment of a murine T cell line (Cl 9) that has been transfected with human IFN-gamma genomic DNA. In contrast, treatment with Ca+2 ionophore alone or in combination with phorbol ester did not enhance IFN-gamma production in a synergistic manner above the level obtained with phorbol ester treatment alone. To determine whether the lack of effect of Ca+2 ionophore is due to a defect in PKC, we compared the level of PKC autophosphorylation in the mouse T cell line (Cl 9), a mouse epidermal cell line (JB6), and purified rat brain PKC by in vitro kinase assays. The results demonstrate that instead of the expected 80-kDa autophosphorylated PKC band seen in purified rat brain PKC or mouse JB6 cell lysates, only a novel 97-kDa Ca+2-independent phosphoprotein was observed in Cl 9 cells. To ascertain if there was any nucleic acid sequence similarity to PKC epsilon, we hybridized Cl 9 poly(A+) RNA with a cloned fragment of the PKC epsilon gene and observed two hybridizing RNA bands (4.4 and 4.0 kb). Our results suggest that the 97-kDa phosphoprotein is similar to, but not identical with, PKC epsilon and is the major PKC expressed in the Cl 9 murine T cell line. These data suggested that the 97-kDa PKC may be responsible for the induction of both the transfected human IFN-gamma gene and the endogenous murine IL-2R alpha-chain.