ABH blood group antigens in human semen.

Human sperm, erythrocytes, and seminal plasma from the blood and semen of 20 men of known ABH, Lewis, and secretor phenotypes were assayed for ABH blood group antigens. A 1:1 correlation was found between the presence of ABH antigens in seminal plasma and on sperm and if the man had a secretor phenotype. Sperm from nonsecretors or from men of dissimilar ABO blood type could adsorb A antigen when incubated with A antigen-containing seminal plasma. The level of ABH antigens in seminal plasma correlated with the level of ABH antigens on the sperm surface. ABH antigens in semen were present only on a minority of spermatozoa as detected by flow cytometry, and the majority of these sperm were not in the swimup fraction. ABH antigens were not present on sperm within the seminiferous tubules of human testicular material. It was hypothesized that ABH antigens found on human sperm were adsorbed from seminal plasma on a minority of the sperm in an ejaculate.