New Form of A‐, B‐, and H‐Blood‐Group‐Active Substances Extracted from Erythrocyte Membranes

The isolation and purification of new group A‐, B‐ and H‐specific substances from human erythrocyte membranes is described. These substances contain galactose, fucose, glucosamine, sialic acid and amino acid residues. The A‐specific substance also contains galactosamine. They contain at most about 2% fatty acids or sphingosine. The substances are serologically active; however, both required combination with phospholipids for development of maximum activity ine haemagglutination inhibition tests. Addition of phospholipids was not required in serological precipitation tests. These blood‐group substances may be used to coat group‐O or Bombay‐Oh red cells, thereby conferring on them A‐, B‐, or H‐activity. They form high‐molecular‐weight aggregates in aqueous solution but disaggregate into smaller units in the presence of sodium dodecylsulphate.