Octapeptide segments from the amino terminus of glycophorin A contain the antigenic determinants of the M and N blood groups systems.
Human red blood cells with phenotype N/N and M/M were tested in an agglutination assay with anti-N and anti-M antibodies, respectively. After incubation of the synthesized octapeptide (Leu-Ser-Thr-Thr-Glu-Val-Ala-Met) from the N-amino terminus of glycophorin A, with anti-N antibody, there was significant inhibition of the agglutination of the N-positive cells. There was also inhibition of the agglutination of the M-positive cells with anti-M antibody by the synthesized octapeptide (Ser-Ser-Thr-Thr-Gly-Val-Ala-Met) from the M-amino terminus of glycophorin A. There was no inhibition, however, of the agglutination of M-positive cells with anti-M antibodies by the N-amino terminal octapeptide. Likewise, the M-amino terminal octapeptide did not inhibit agglutination of N-positive cells with anti-N. Because the synthesized octapeptides contained no carbohydrate, the anti-N and anti-M specificity appears to be determined principally by the peptides themselves. Further studies with the use of chimeric peptides indicate that the amino terminal amino acid leucine of N-glycophorin A is a primary determinant of the N antigen, whereas the amino terminal serine of M-glycophorin A is a primary determinant for the M antigen.
Hematology Section, Veterans Administration Medical Center, NY.
J T
JT
Pedersen
H
H
Kaplan
L
L
Wedeck
R B
RB
Murphy
J
J
LoBue
M R
MR
Pincus
D000595:Amino Acid Sequence; D000906:Antibodies; D000939:Epitopes / Q000032:analysis*; D004912:Erythrocytes / Q000276:immunology; D005361:Ficain; D006021:Glycophorins / Q000276:immunology*; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D008951:MNSs Blood-Group System / Q000276:immunology*; D008969:Molecular Sequence Data; D009439:Neuraminidase; D009842:Oligopeptides / Q000138:chemical synthesis
D000906:Antibodies; D000939:Epitopes; D006021:Glycophorins; D008951:MNSs Blood-Group System; D009842:Oligopeptides; D009439:Neuraminidase; D005361:Ficain