IMMUNITY TO REINFECTION AND IMMUNIZATION OF MALE GUINEA-PIGS AGAINST URETHRAL INFECTION WITH THE AGENT OF GUINEA-PIG INCLUSION CONJUNCTIVITIS

Background and Objectives: There is little information available on im munity of males to chlamydial infection; after recovering from a prima ry urethral infection or after immunization with chlamydial antigen, T he guinea pig model of genital infection using the chlamydial agent of guinea pig inclusion conjunctivitis was utilized to evaluate the prot ective immune response in these circumstances, Goal: To determine whet her immunity to reinfection develops after a primary urethral infectio n and whether immunity develops as a result of immunization with inact ivated chlamydiae, Study Design: Groups of five male guinea pigs each in two separate experiments were infected in the urethra with chlamydi ae and challenged with a fresh inoculum at either 30, 75, or 150 days after infection, The course of the challenge infection was then determ ined, Similarly, guinea pigs were: immunized subcutaneously with ultra violet-inactivated chlamydial elementary bodies and the course of uret hral infection was determined when inoculated 2 weeks after immunizati on, Results: Male guinea pigs were highly resistant to reinfection aft er a primary urethral infection, Animals that were immunized with inac tivated chlamydiae generally became infected upon challenge, but the i ntensity of the infection was markedly reduced. Conclusions: Male guin ea pigs possess protective mechanisms that make them more resistant to repeat chlamydial genital infection for a longer period of time than is seen in female guinea pigs, In addition, immunization of males with inactivated chlamydial antigen by a parenteral route is able to elici t a protective response to urethral infection with chlamydiae.