Experimental trachoma in subcutaneous conjunctival autografts in macaques

To study chlamydial conjunctivitis, conjunctival autografts subcutaneously implanted in pockets on the abdomens of rhesus (Macaca mulatta) and pig-tailed (M. nemestrina) monkeys were inoculated percutaneously (4-10 X 10(4) inclusion-forming units per pocket) with trachoma strains of Chlamydia trachomatis (serovars B & C). These conjunctival pockets were removed on days 2, 3, 4, 5, 6, 7, 8, 10, 14 and 16 post-inoculation (pi). Tissues (at least two samples at each time interval) were prepared either for reisolation of the organisms by cell culture or histologic examination by light and electron microscopy. Control tissue, inoculated with either HeLa cell material or UV-inactivated organisms, were prepared in parallel. Bloods were drawn and tear strips taken at weekly intervals for 8 weeks. A total of 221 bulbar and 99 palpebral conjunctival pockets were established over time with the success rate of 75% and 88%, respectively, in six rhesus and ten pig-tailed monkeys. Histological examination revealed widespread infiltration of mixed polymorphonuclear and mononuclear cells on days 2 and 3 pi. By day 5 pi, lymphocytes had migrated into the thinned epithelial layer. Patches of inflammatory infiltrate similar to trachoma follicles were observed, although distinct germinal centers were absent. Surface morphologies of normal and infected pocket conjunctiva were examined by scanning electron microscopy. Normal tissue was characterized by a regular mosaic pattern of closely packed epithelial cells containing numerous microvilli. Infected tissue was edematous, and the continuity of the mucosal surface had been altered. Chlamydiae were reisolated from the pockets on days 2, 3, 6, 8 and 10 pi.(ABSTRACT TRUNCATED AT 250 WORDS)