A and b antigenicity of human spermatozoa and buccal epithelial cells

The source of A and B antigens on the surface of erythrocytes, spermatozoa and buccal epithelial cells was studied using two kinds of monoclonal antibodies of differing specificity. The first, anti-Ar, reacts with the erythrocyte A antigen but not with the soluble A antigen found in secretions such as saliva. Similarly, anti-Br reacts with the erythrocyte B antigen but not with the soluble B antigen present in secretions. The second type of monoclonal antibody, anti-A_r+s, reacts with both the erythrocyte A antigen and with the soluble A blood group substance. Similarly, the anti-B_r+s reacts with both the erythrocyte B antigen and with the soluble B blood group substance. The spermatozoal A antigen reacts only with the anti-A_r+s monoclonal antibody whereas buccal epithelial A antigen reacts with both anti-A_r and with anti-A_r+s. Spermatozoal B antigen reacts only with anti-B_r+s whereas buccal epithelial B antigen reacts with both anti-B_r and anti-B_r+s. Buccal cell A and B antigens appear to be integral to the membrane or at least tightly bound whereas the spermatozoal A and B antigens are adsorbed from seminal plasma and loosely bound.