Immunopathology of Reproductive Disorders of Animals

The uterus’ endometrial lining is pivotal for reproductive cycles, implantation, and fetal health until parturition. Serving as gatekeepers, mucosa lining and epithelial cells prevent pathogen entry from the vagina into the uterus, with infections reaching through the vaginal route or cervix. Vaginal innate immunity involves physical, chemical, and cellular components, creating a microenvironment regulating immune responses influenced by sex hormones and the microbiome. Physiological processes like menstruation, conception, and pregnancy impact the vaginal mucosal immune system. The vagina’s stratified squamous epithelium acts as a barrier, sensing pathogens and activating immune cells to drive inflammation and responses. During healthy pregnancy, the uterus maintains a sterile environment, as bacterial presence poses a risk of fetal impact and systemic inflammation. Bacteria typically invade the uterine cavity from the lower urogenital tract, ascending through the cervix, breaching the placental barrier to reach the amniotic fluid and placenta. Uterine infections, common in animals, can cause infertility, abortion, and clinical disease. Some infections ascend via the cervix, while others reach the uterus through circulation. This book chapter delves into the intricacies of immunity and inflammation in the uterus.