E. histolytica infections induce a state of transient suppression of cell-mediated immunity. As macrophages are involved in host defense in amebiasis, we determined whether soluble amebic lysates (Eh) can modulate TNF-alpha, IL-1 alpha/beta and c-fos gene expression in naive bone marrow-derived macrophages (BM delta). By Northern analysis, the RNA production of these genes after 0, 0.5, 1 and 3 h exposure to Eh was determined and compared to lipopolysaccharide (LPS) stimulation. In response to Eh, TNF-alpha mRNA was increased two fold while IL-1 alpha/beta RNA levels were increased 6- and 19-fold, respectively. Pretreatment of BM delta with H7, a PKC inhibitor, abrogated Eh induced TNF-delta gene expression and reduced IL-1 alpha/beta gene expression 3.5- to 4-fold over control levels. We conclude that E. histolytica stimulates BM delta to induce TNF-alpha gene expression through a PKC-dependent pathway and IL-1 alpha/beta gene expression partially through PKC and another yet undetermined pathway(s).
Animals Bone Marrow Cells