Mucosal immune system of the human genital tract

In contrast to the pronounced dominance of secretory IgA over other immunog lobulin isotypes in human saliva, tears, milk, and gastrointestinal fluids, secretions of both female and male genital tracts contain more IgG than se cretory IgA. Both IgG and IgA are derived, to a variable degree, from the s ystemic immunoglobulin pool as well as from local synthesis. The origin of IgG- and IgA-plasma cell. precursors destined for the genital tract is unkn own, but indirect evidence suggests that mucosal inductive sites localized in the rectum, small intestine, and especially in the nasal cavity contribu te such precursors to the female genital tract. Several studies indicated t hat intranasal immunization of various species, including humans, eras effi cient at inducing antigen-specific antibody responses in the female genital tract; however, whether this route is also effective in males has not been explored.