The bm23 spontaneous variant in the H2-Kb sequence consists of two nucleotide substitutions resulting in two amino acid changes, which are predicted to impact the TCR interaction and peptide binding domain, R75H and D77S. The H2bm23 mutant allele causes an increase in the percentage of the CD8 T cells bearing Valpha3.2 both in peripheral T cells and CD8 single positive thymocytes. (sim et al, 1997.)
H2Kbm23 is a spontaneous mutation initially identified in one male and two female progeny of a C57BL/10SnEg female bred to B10.D2/nSnEg male. Although the male had been treated with ethylnitrosourea, the H2b haplotype was passed from the female and thus bm23 was a spontaneous mutation. (Egorov and Egorov, 1984). Embryos were cryopreserved in 1996.