HLA expression on human germinal cells.

Ejaculated human seminal plasma cells obtained from 46 healthy men and 48 infertile patients were tested for expression of HLA class I and II antigens by complement-mediated cytotoxicity, cell-binding radioimmunoassay (CB-RIA), and an ELISA involving monoclonal antibodies (mAbs). In a group of healthy men tested for HLA expression on human spermatozoa, 4 of 46 were positive for class I and II HLA antigens. However, the results were negative in a second examination of the same donors, possibly on account of alterations with time in the expression of various subpopulations of cells which are antigen positive or antigen negative. In a group of infertile patients, we found positive expression of HLA class I and II antigens in 7 of 48 men. The samples contained immature and mature sperm but no contaminating leucocytes or epithelial cells.