Semiquantitation of ABH antigens specific for red blood cells.

H and A antigens expressed only in the RBC were quantitated using specific antisera, and the amount of the antigens was compared with that of total H and A antigens shared by the RBC and saliva. Total H antigen decreased in the order of O, A, B and AB blood groups. However, H antigen specific for the RBC distributed similarly among four blood groups. In addition, the amount of total A antigen in A group was more than that of AB group, but the difference in the amount of A antigen specific for the RBC was not significant between the two blood groups. B antigen specific for the RBC was not examined because of failure in preparing specific anti-B serum. In conclusion, the quantitative difference of the total H or A between A and AB groups might be due to the difference in the amount of antigen common to the RBC and saliva but not one specific for the RBC.