A and B and A(1)Le^b Substances in Glycosphingolipid Fractions of Human Serum

A and B and A(1)Le^b substances were adsorbed onto red cells exposed to glycosphingolipid fractions prepared from the serum of group A and B and A(1),Le(a — b+) donors. Group O cells exposed to fractions prepared from the serum of group A or B donors were agglutinated by an IgM cross-reacting antibody present in some group O sera. Cells exposed to fractions from A(1),Le(a-b + ) serum were agglutinated by anti- A(1)Le^b. The amount of A substance in the fractions was related to the A subtype (A(1) or A(2)) and to the Lewis and secretar phenotype of the donor. The uptake of blood-group substances from the lipid fractions was inhibited by the addition of whole serum to the fractions.