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-Ar+s, reacts with both the erythrocyte A antigen and with the soluble A blood group substance. Similarly, the anti-Br+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-Ar+s monoclonal antibody whereas buccal epithelial A antigen reacts with both anti-Ar and with anti-Ar+s. Spermatozoal B antigen reacts only with anti-Br+s whereas buccal epithelial B antigen reacts with both anti-Br and anti-Br+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.