Biochemical documentation of allelic variation of the I-E antigens of the d,k, p,r, and u haplotypes

The extent of allelic variation of the E and E polypeptide chains of the I-E antigens from the H-2> ^d ,H-2 ^k , H-2 ^p , H-2 ^r , and H-2 ^u haplotypes is described. E and E chains were individually labeled with arginine or lysine and compared by tryptic peptide analysis. The results indicate minimum variability among the E polypeptides encoded by the d, k, p, and r haplotypes. However, the E ^u chain differed significantly from the other allelic E gene products. On the other hand, the E alleles demonstrated substantial variability with the E ^d being notably less similar to the other alleles than they are to each other. These findings are consistent with a number of observations regarding the serology and functions of the I-E antigens.Abbreviations MHC major histocompatibility complex - NMS normal mouse serum - NP-40 Nonidet P-40 - NTS 0.25% NP-40, 10 mM Tris-Cl, 0.15 M NaCl (pH 7.4) - SDS sodium dodecylsulfate - SDS-PAGE polyacrylamide gel electrophoresis in the presence of SDS