RT Journal Article SR Electronic T1 Evidence for invasion of a human oral cell line by Actinobacillus actinomycetemcomitans. JF Infection and Immunity JO Infect. Immun. FD American Society for Microbiology SP 2719 OP 2726 VO 59 IS 8 A1 Meyer, D H A1 Sreenivasan, P K A1 Fives-Taylor, P M YR 1991 UL http://iai.asm.org/content/59/8/2719.abstract AB Actinobacillus actinomycetemcomitans, an oral bacterial species associated with periodontal disease, was found to invade human cell lines. Invasion was demonstrated by recovery of viable organisms from gentamicin-treated KB cell monolayers and by light and electron microscopy. Internalization occurred through a cytochalasin D-sensitive process. Invasion efficiencies of some A. actinomycetemcomitans strains were comparable to those of invasive members of the family Enterobacteriaceae. Differences in invasiveness were correlated with bacterial colonial morphology. Smooth variants invaded more proficiently than rough variants. A. actinomycetemcomitans can undergo a smooth-to-rough colonial morphology shift which results in the loss of invasiveness. Coordinated regulation of genes involved in the rough-to-smooth phenotypic transitions may play a role in the episodic nature of periodontal disease.