Complement fixation antibodies to glycosphingolipids in sera of rare blood group p and Pk phenotypes.

Blood group P antigen and Pk antigen were recently identified as glycosphingolipid globoside, GalNAc(beta, 1 leads to 3)Gal(alpha, 1 leads to 4)Gas(beta, 1 leads to 4)Glc(beta, 1 leads to 1)ceramide, and trihexosylceramide, Gal(alpha, 1 leads to 4)Gal(beta, 1 leads to 4)Gld(beta, 1 leads to 1)ceramide, respectively (Naiki & Marcus, 1974). The presence of antibodies to both antigens in the sera from rare p donors and antibodies to P antigen in the serum from a rare Pk donor were first demonstrated by the complement fixation test with the optimal antigen preparations containing each purified glycoplipid, lecithin and cholesterol. In the serum from a p donor, most of antibody population of anti-P was IgM and was cross-reacted to Forssman glycolipid, GalNAc(alpha, 1 leads to 3)GalNAc(beta, 1 leads to 3)Gal(alpha, 1 leads to 4)Gal(beta, 1 leads to 4)Glc(beta 1 leads to 1) ceramide, but the rest of the anti-P antibodies and most of anti-Pk antibodies were IgG and had marked specificities for globoside and trihexosylceramide, respectively.