A model system for the study of genital infection by Chlamydia will be investigated using guinea pigs and the agent of guinea pig inclusion conjunctivitis (Gp-ic). Male guinea pigs will be inoculated intraurethrally and the clinical response determined. Similar experiments will be performed on females inoculated intravaginally. The course of infection will be followed by examination of smears, histopathology (light and electron microscopy), isolation of Gp-ic, detection of Gp-ic antigen by immunofluorescence, cellular immune response, and determination of antibodies. The presence of antibodies in genital secretions of females will be examined and the role of secretory IgA investigated. The effect of infection on offspring will be studied by infecting pregnant females. The intrarectal route of inoculation will be studied to extend the use of this model system. Experiments will also be conducted to learn the value of guinea pigs for the study of genital infection by chlamydial agents isolated from cases of lymphogranuloma venereum and other Group A chlamydial infections.