Optimized assay for antisperm cell-mediated immunity

Previous studies on antisperm cell-mediated immunity (CMI) have been confounded by the presence of immunogenic leukocytes in sperm antigen preparations. In this study we isolated pure populations of viable spermatozoa on discontinuous Percoll gradients, and utilized sonicated and cavitated extracts, as well as live motile spermatozoa, to measure cellular immunity to spermatozoa in vasectomized men, men with proven fertility, infertile women, fertile women and umbilical cord blood. Using a thymidine incorporation assay to assess lymphocyte proliferation, nine out of 13 (69%) vasectomized men and five out of 10 (50%) fertile men responded to sperm extracts. Lymphocyte proliferation to sperm extracts was also observed in both infertile and fertile women (27 and 50% respectively). In addition, viable sperm preparations promoted lymphocyte responses in five out of eight (63%) fertile women, seven out of 11 (63%) healthy men and four out of 11 (45%) cord blood specimens. Furthermore, four out of 11 (36%) healthy normal men responded to autologous spermatozoa. No relationship between serum antisperm antibodies, as measured with the Immunobead test, and sperm CMI was observed in any group. This study provides evidence that lymphocytes from fertile as well as infertile men and women and sperm-naive newborn infants proliferate when exposed to viable spermatozoa or sperm extracts. Thus the lymphocyte proliferation assay does not appear to be useful in the diagnosis of immunological infertility, but immunological recognition of spermatozoa may be a common feature that could have a role in fertility.