Heterogeneity of antigenic determinants on human spermatozoa: relevance to antisperm antibody testing in infertile couples.

Sera from 1074 male and 947 female partners of infertile marriages were tested by enzyme-linked immunosorbent assay for antibodies to motile sperm purified from ejaculates of the male partners or a donor. In men, 9.2% of the sera were positive for immunoglobulin A, 7.9% for immunoglobulin G, and 5.1% for immunoglobulin M antibodies to their own sperm. In women, immunoglobulin M antibodies to the husband's sperm predominated (10.1%), with immunoglobulins G (8.3%) and A (5.9%) following. Differences between men and women in the incidence of immunoglobulin A (p less than 0.01) and M (p less than 0.005) antibodies were significant. In both sexes only about two thirds of the antibody-positive sera remained positive when donor sperm was substituted for partners' sperm in the assay. The decreased occurrences of antisperm immunoglobulins A (p less than 0.025) and G (p less than 0.01) in men and of immunoglobulins G (p less than 0.025) and M (p less than 0.01) in women were significant. Incubation of donor sperm in the husband's cell-free seminal fluid before analysis led to the acquisition of sperm reactivity with husband-specific antisperm antibodies in only one of eight women. Women with husband-specific antisperm antibodies also exhibited differences in their cell-mediated immune responses to sperm from various men. Thus sperm from different individuals vary in their ability to react with the immune system of sperm-sensitized men or women.