Evidence for minor structural variations of class II genes in wild and inbred mice.

We organized 29 B10.W lines into eight antigenic groups on the basis of similarities in the antigenic phenotypes of their class II antigens. Tryptic peptide fingerprint comparisons of class II antigens in different antigenic groups detected structural variations in 30 to 60% of the tryptic peptides. In contrast, less than 10% of the tryptic peptides were distinguishable in comparisons of class II antigens within the same antigenic group. These results suggest structurally discrete allelic families of class II genes exist in wild mouse populations.