BINDING SPECIFICITIES OF 8 MONOCLONAL-ANTIBODIES TO HUMAN GLYCOPHORIN-A - STUDIES WITH MCM, AND MKEN(UK) VARIANT HUMAN-ERYTHROCYTES AND M-TYPE AND MNV-TYPE CHIMPANZEE ERYTHROCYTES

  • 1 January 1984
    • journal article
    • research article
    • Vol. 133  (6) , 3149-3155
Abstract
Four newly derived mouse monoclonal antibodies to human glycophorin A are described. Three of these antibodies bind preferentially to the N form of glycophorin A; the 4th recognizes a shared determinant of the M and N forms. All 4 antibodies are directed toward the 39 amino acid, amino-terminal portion of the protein, and the N-specific antibodies require for binding the presence of N-acetylneuraminic acid on the glycosidically linked oligosaccharides. Cross-reaction of the N-specific antibodies to homozygous MM erythrocytes appears to result from binding to glycophorin B. These antibodies together with 4 previously reported glycophorin monoclonal antibodies, including 2 that specifically recognize the M form of glycophorin A, were tested for binding to McM and MkEn(UK) variant human erythrocytes and M- and MNV-type chimpanzee erythrocytes. Results obtained for 5 of the 6 M- or N-specific monoclonal antibodies point to the general immunodominance of the amino-terminal serine-leucine polymorphism and the requirement for sialic acid. One of the 2 M-specific monoclonal antibodies, 9A3, discriminates between the M, N and Mc forms of glycophorin A solely on the basis of the amino-terminal serine-leucine polymorphism. The other M-specific antibody, 6A7, requires a more complex determinant involving the glycine-glutamic acid polymorphism at the 5th position in the sequence as well. The epitopes for all 3 N-specific monoclonal antibodies include the amino terminal leucine that occurs in the N form of glycophorin A and may also include the glutamic acid that occurs at position 5. The proposed Lepore-type glycophorin A-B hybrid gene rearrangement for the En(UK) allele found in the English En(a-) family was supported. The expression of the M-like glycoprotein on chimpanzee erythrocytes and the presence of a human glycophorin B-like antigen on the MNV-type cells were estimated.