Abstract
REPRODUCTION is intricately involved with the immune system. The maternal immune system must tolerate foreign (paternal) antigens while maintaining resistance to microbes and tumor antigens. Immunologic interference in biological activities, such as formation of antibodies to sperm or failure of proper confrontation of fetal alloantigens by the maternal immune system, may result in reproductive failure. IMMUNOLOGY OF REPRODUCTION IN THE FEMALE The female genital tract is exposed to sperm and seminal fluid proteins, both of which are potentially antigenic. Nevertheless, in most women without infertility problems, there is no antibody formation to sperm or evidence that exposure produces any humoral or cellular immunity. The uterus is exposed to all substances that enter the vagina, such as sperm, seminal plasma, and microorganisms. Since the uterus handles bacterial invasion of the endometrial cavity well without frequent infections of the endometrium, it is assumed that the immune system in the uterus is intact.