The pathogenesis of recurrent ocular chlamydial infections is thought to be immunologically mediated (i.e., hypersensitivity). However, due to the lack of an appropriate animal model of ocular chlamydial infections, the immunological response to chlamydial antigens during infection and challenge has not been characterized. We have chosen to study the immunopathology of guinea pig inclusion conjunctivitis (GPIC), a Chlamydia psittaci strain which produces ocular and genital infections in guinea pigs. We have characterized GPIC primary infection clinically and are in the process of characterizing the histopathology of the conjunctiva during primary infection. In addition, we have characterized a delayed type hypersensitivity response to high doses of viable GPIC and to a Triton X-100 extract of GPIC. GPIC recombinant clones producing cutaneous hypersensitivity in immune animals are being characterized to identify the chlamydial antigen which elicits the hypersensitivity response. The immunodominant antigens during primary infection and following challenge have been identified and recombinant clones expressing these proteins have been isolated.
