Analysis of the fine specificities of 11 mouse monoclonal antibodies reactive with type 2 blood group determinants

The specificity of 11 mouse monoclonal antibodies reacting selectively with type 2 blood group structures was analyzed in detail by studying their reactivities with a panel of standard glycolipids, glycolipids from erythrocytes and blood group glycoproteins. The antibodies reacted with monofucosyl type 2 H, difucosyl type 2 structures (Le gamma) or both; none of the antibodies reacted with type 1 (H, Lea, or Leb) structures. Only a small proportion of the antibodies were completely specific for either type 2H or Le gamma structures. None of the antibodies had identical patterns of reactivity and their specificities were individually distinct. Seven antibodies preferentially agglutinated O and A2 erythrocytes. Anti-Le gamma-specific antibodies, except mAb101, did not agglutinate erythrocytes or react with glycolipids from erythrocytes, indicating the absence of Le gamma structures in erythrocyte glycolipids. The ability of some antibodies to react with A erythrocytes was shown to be due to cross-reactivity of the antibodies with type 3 (repetitive) A structures. The study demonstrates that monoclonal anti-carbohydrate antibodies tend to react with a range of related, and even distantly related, structure in a pattern characteristic of each antibody and that very few antibodies have extremely restricted specificities.