Ultrastructure of Chlamydia trachomatis infection of the mouse oviduct.

Chlamydial inclusions were found in the luminal epithelium of all segments of the oviducts (ostium, ampulla, and isthmus) of mice experimentally inoculated with the mouse pneumonitis (MoPn) biovar of Chlamydia trachomatis. Electron microscopy of infected oviducts revealed chlamydial inclusions in both ciliated and nonciliated cells of the oviduct epithelium. Inclusions contained typical elementary, intermediate and reticulate bodies as well as numerous "miniature reticulate bodies" and membrane ghosts. Small, vesicle-like structures were observed in infected cells near inclusions but were not seen in apparently uninfected cells nor in the oviducts of mice inoculated with the control (sterile tissue culture supernate) suspension. Chlamydia-like particles were seen in vacuoles of polymorphonuclear leukocytes. Intracellular Chlamydia-like particles were not seen in any other cell type in the mouse oviduct. Infection of the mouse oviduct with MoPn is a convenient model for the study of C. trachomatis morphology in vivo.