Enrichment of gamma delta T lymphocytes in human semen: relation between gamma delta T cell concentration and antisperm antibody status.

The presence and relative concentrations of T lymphocytes bearing the alpha beta and gamma delta cell receptor (TCR) in human semen were assessed and related to the occurrence of auto-antibodies to sperm in semen and peripheral blood. Using an immunoperoxidase technique, and monoclonal antibodies to the beta chain and delta chain of the human TCR, both alpha beta and gamma delta T cells were detected in each of 30 semen samples examined. In seven men with antisperm antibodies both on their ejaculated sperm and in their serum, the mean concentrations of gamma delta and alpha beta T cells were 3,560 and 3,230 cells/ml semen, respectively. In seven men with antisperm antibodies in serum only, the concentrations of gamma delta and alpha beta T cells were 860 and 1,280 cells/ml, while in 16 men with no evidence of auto-immunity to sperm there was a mean of 350 gamma delta T cells and 610 alpha beta T cells/ml. In contrast, the concentrations of gamma delta and alpha beta T cells in peripheral blood from these same men were unrelated to antisperm antibody status. The mean ratio of alpha beta to gamma delta T cells in peripheral blood of all subjects was 12. The ratio of alpha beta to gamma delta T cells in semen were 0.9 for men with sperm-bound and serum antisperm antibodies, 1.5 for men with antisperm antibodies in serum only and 1.7 for men lacking these auto-antibodies. These results were confirmed by FACS analysis. Thus, gamma delta T cells in human semen comprise a greatly increased proportion of the total T cell population as compared to the circulation. In addition, the relative and absolute concentration of gamma delta T cells are further elevated in semen from men with evidence of localized auto-immunity to their own sperm. These results suggest that gamma delta T cells may function in immune surveillance in the non-sterile proximal portions of the male genital tract and that replication of T cells bearing the gamma delta TCR accompanies an autoimmune response to sperm.