Host response to primary Chlamydia trachomatis infection of the fallopian tube in pig-tailed monkeys

Experimental acute salpingitis was produced in four pig-tailed monkeys, Macaca nemestrina, by intratubal inoculation with Chlamydia trachomatis (serotypes E or F). The organisms were reisolated from both the endosalpinx and endocervix as early as 1 week after the original inoculation. Endosalpinx cellular responses to the infection were examined by light, transmission, and scanning electron microscopy. A moderate lymphocyte infiltration was detected in the submucosa on day 7. By days 14 and 21 the lymphocytic infiltration was heavy and extended into both the submucosa and the mucosa; the infiltration subsided by day 35. Epithelial cell degeneration occurred in close approximation to lymphocytes, suggesting the immunologic basis of tissue destruction. Scanning electron microscopy revealed extensive deciliation and increased plasmalemmal alterations of nonciliated cells. The presence of C. trachomatis in frozen and deparaffinized tissues was demonstrated by immunofluorescence and immunoperoxidase staining with monoclonal antibody to C. trachomatis. Only secretory cells contained chlamydial inclusions. A humoral immune response to C. trachomatis was demonstrated by microimmunofluorescence. No histologic or immunologic evidence of infection was present in two control monkeys inoculated with HeLa cell material. The histopathologic and immunologic findings of this study establish the pig-tailed monkey as a useful model for further studies of the pathogenesis and pathophysiology of chlamydial salpingitis.