H-Y-ANTIGEN EXPRESSION PATTERNS IN HUMAN X-CHROMOSOME-BEARING AND Y-CHROMOSOME-BEARING SPERMATOZOA

PROBLEM: Restricted expression of H-Y antigen on Y-chromosome-bearing sperm has been reported in some species, although such preferential ex pression for H-Y antigen in human sperm has yet to be described. In th is study, an immunomagnetic approach was used to characterize antigen expression patterns as a function of sex-chromosome content. METHOD OF STUDY: Human sperm was treated with monoclonal immunoglobulin (Ig) M antibodies directed against H-Y antigen. This preparation then was inc ubated with sheep antimouse IgM antibody affixed to paramagnetic beads , which then were exposed to a magnetic field and sorted. X- and Y-chr omosome frequencies in the two subgroups of sperm were assayed by mult iprobe fluorescent in situ hybridization (FISH). RESULTS: Sperm were i mmunomagnetically separated into two populations: a reactive group (pr esumably, H-Y Ag+); and a nonreactive group (presumably, H-Y Ag-). Tri ple-color FISH analysis of 1,600 spermatozoa (800 in each group) showe d the antigen's expression to be somewhat more prevalent among Y-chrom osome-bearing sperm (54.1%), but a large pro portion of Y-chromosome-b earing sperm (49.0%) did not express this antigen. The difference was not significant (P = 0.43).CONCLUSIONS: The expression of H-Y antigen has a slightly higher frequency in human sperm containing the Y-chromo some, but its expression among X-chromosome-bearing sperm also is cons iderable. Current immunologic techniques relying on this antigen are u nlikely to effect the sex selection of human sperm.