ULTRASTRUCTURAL-CHANGES IN AVIAN CHLAMYDIA-PSITTACI SEROVAR A-INFECTED, B-INFECTED, AND D-INFECTED BUFFALO GREEN MONKEY CELLS

In order to find an explanation for the observed differences in levels of pathogenicity in turkeys of Chlamydia psittaci 84/55 (avian serova r A), 89/1326 (avian serovar B), 92/1293 (avian serovar D), and the Te xas Turkey strain (avian serovar D) (P. B. Wyrick, J. Choong, S. T. Kn ight, D. Goyeau, E. S. Stuart, and A. B. MacDonald, Immunol, Infect, D is, 4:131-141, 1994), the reproductive cycles of organisms of the four strains were studied in Buffalo Green Monkey cells by transmission el ectron microscopy, immunoelectron microscopy, and flow cytometry, Orga nisms of strains most pathogenic in turkeys, namely, the serovar A str ain and the 92/1293 serovar D strain, (i) replicated faster, since at 50 h postinoculation significantly larger inclusions with more numerou s infectious organisms were observed than with the less pathogenic str ains; (ii) were often found devoid of inclusion membranes scattered th roughout the cytoplasms; and (iii) induced severe degenerative changes in Buffalo Green Monkey cells, By immunoelectron microscopy and flow cytometry, chlamydial antigens could not be detected in the plasma mem branes of infected host cells, However, the presence of chlamydial ant igens in inclusion membranes was demonstrated by immunoelectron micros copy.