Sex Hormone, Glucocorticoid, and Cytokine Regulation of Mucosal Immunity in the Male and Female Reproductive Tract

Present throughout the body, the secretory immune system is the first line of defense at mucosal surfaces against bacterial and viral organisms that threaten to disrupt systemic homeostasis (for reviews see1,2). Characterized by secretory IgA and IgG in secretions that bathe mucosal surfaces of the respiratory, gastrointestinal, and urogenital tracts, protection is the result of successful interactions between the humoral and cellular components of the immune system. As the predominent immunoglobulin in mucosal secretions, IgA is transported from tissue to lumen through epithelial cells by secretory component (SC), the IgA receptor.2 Acting through afferent and efferent arms, the mucosal immune system recognizes and responds to antigen through both cell-mediated and humoral immune actions against pathogens.2,3 Protection at these sites is conferred by T and B lymphocytes, monocytes, and macrophages, as well as other antigen-presenting cells that monitor mucosal surfaces and respond to antigenic challenge with specific antibodies, 1,4 phagocytosis, 5 and cytotoxic mechanisms6 to destroy and/or contain antigens.