Failure to identify HLA ABC and Dr antigens on human sperm

An indirect radiolabeled antiglobulin assay (IRAA), adsorption procedures, and an indirect immunofluorescent assay using cytofluorometry (IFAA) failed to identify HLA ABC or D/Dr antigens associated with untreated human sperm or human sperm exposed to capacitating conditions. Two monoclonal clones against HLA ABC and two clones against Dr antigens were utilized. Test results in the IRAA were not different regardless of whether sperm from fertile men or human red blood cells were employed in the IRAA. However, there were highly significant differences in the IRAA between the HLA antigen expression of human sperm and leukocytes. If the antihuman HLA monoclonal antibody was preadsorbed with 25 X 10(6) sperm, there was no diminution in the ability of the adsorbed antibody to identify HLA antigens on leukocytes; however, preadsorption with 2.5 X 10(6) leukocytes reduced the activity of the monoclonal antihuman HLA antibody to levels equivalent to background activity.