Characterization of the epitope recognized by a monoclonal antibody highly specific for blood group M antigen.
The mouse monoclonal antibody M2A1 of IgG1 class, which is highly specific for blood group M antigen, was obtained and characterized by means of hemagglutination, enzyme-linked immunosorbent assay, immunoblotting, and inhibition assays. The use of modified M glycoprotein preparations for inhibition tests and of variant McN and Henshaw red cell membranes for immunoblotting showed that M2A1 recognized an epitope including the NH2-terminal serine and sialic acid residues of glycophorin A, whereas the fifth glycine residue was not involved. The reactivity of the antibody with M antigen was distinctly dependent on ionic strength and pH; the optimum was at pH 8 to 9. The alpha-amino group of terminal serine residue was not necessary for the reaction with M2A1 antibody, and the results obtained suggested that the positive charge of this group contributed to decreasing antigen-antibody reactions at pH below 8. The reaction of the antibody with blood group N antigen was not detectable in any of the assays used.
Jaskiewicz
E
E
Department of Immunochemistry, Polish Academy of Sciences, Wroclaw.
Moulds
J J
JJ
Kraemer
K
K
Goldstein
A S
AS
Lisowska
E
E
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D003429:Cross Reactions; D000939:Epitopes; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D008951:MNSs Blood-Group System / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D012794:Sialic Acids / Q000276:immunology
D000596:Amino Acids; D000911:Antibodies, Monoclonal; D000939:Epitopes; D008951:MNSs Blood-Group System; D012794:Sialic Acids