MURINE MODEL OF OCULAR INFECTION BY A HUMAN BIOVAR OF CHLAMYDIA-TRACHOMATIS

Purpose. A human biovar of Chlamydia trachomatis was used to develop a murine model of ocular chlamydial infection. The inbred mouse model w ill allow detailed immunologic studies during ocular infection, and us e of a human biovar for infection may aid in identification of appropr iate vaccine strategies against chlamydial infections. Methods. BALB/c , C3H/HeN, and C57B1/6J mice (n = 5 to 10 mice/group) were topically i nfected in the conjunctiva with C serovar of C. trachomatis. The effec ts were tested of single and repeated infection with 5000 inclusion-fo rming units (IFU) in 5 mu l and different inoculum doses. Conjunctival surfaces of both eyes were swabbed for microbiologic signs (isolation culture or direct fluorescent antibody staining) of infection over 4 to 6 weeks. Conjunctivae were removed for histopathologic study, and l ymphocytes from draining cervical lymph nodes and spleens were tested for chlamydia-specific proliferative responses. Serum was obtained fro m all mice and tested for anti-chlamydial antibodies. Results. BALB/c and C3H/HeN mice developed dose-dependent microbiologic, histopatholog ic, and immunologic evidence of ocular infection. Eyes of mice were cu lture-positive from day 7 through at least day 21, with the peak of in fection at days 10 to 14 after infection. Histopathologically, the dev elopment of conjunctival subepithelial mononuclear infiltration, exuda te, and loss of goblet cells occurred within 1 week. Dose-dependent ly mphoproliferative responses to whole chlamydial elementary bodies were observed; anti-chlamydial antibody was detected by immunoblotting onl y in infected mice. Conclusions. Several strains of inbred mice are su sceptible to human chlamydial biovars and may provide a useful alterna tive disease model in which to study the immunopathogenesis of ocular chlamydial infection and tests of vaccine candidates derived from clin ically relevant human biovars.