Specific antibodies for desialized M and N blood group antigens

Antisera obtained by immunizing rabbits with desialized M and N blood group glycoproteins (M' and N' glycoproteins) agglutinate desialized erythrocytes and precipitate desialized glycoproteins, but they do not react with sialic acid containing erythrocytes or glycoproteins. By absorption of anti-M' serum with N' glycoprotein, and of anti-N' serum with M' glycoprotein, reagents specifically agglutinating M' or N' erythrocytes were obtained. The absorbed anti-M' and anti-N' sera were specifically inhibited by M' or N' glycoproteins, respectively. The results show that sialic acid residues of red cell glycoproteins are not essential for the differentiation of M an N blood group determinants.