This variant MHC class II allele, H2-Ab1bm12, is associated with increased resistance to experimental autoimmune myasthenia gravis (EAMG). Mice congenic for H2 alleles are widely used in immunologic research and often vary in immune response and pathogen susceptibility from the recipient strain.Read More +
H2-Ab1bm12 differs from H2-Ab1b by 3 nucleotides resulting in amino acid substitutions in three codons in the beta1 exon. Surface expression of MHC class II A is reduced as is the amount of invariant chain co-precipitated with the alpha and beta chains. This variant MHC class II allele is associated with increased resistance to experimental autoimmune myasthenia gravis (EAMG). Homozygous mice exhibit lower IFNG and IL10 release and decreased calcium mobilization in response to immunization with acetylcholine receptor and its dominant peptide alpha146-162. Like other mice with the H2b haplotype, this strain is MHC class II IEb; the b allele is considered a null allele. Mice congenic for H2 alleles are widely used in immunologic research and often vary in immune response and pathogen susceptibility from the recipient strain.
The H2-Ab1bm12 allele originated as a spontaneous mutation in a C57BL/6Kh x BALB/cKh F1 female, and was shown to have occurred in the C57BL/6Kh H2b haplotype. The female was crossed to the C57BL/6Kh background for 10 generations. This variant MHC class II allele differs from H2-Ab1b by 3 nucleotides resulting in amino acid substitutions in three codons in the beta1 exon (Ile67Phe, Arg70Gln, Thr71Lys). This strain was transferred from Dr. Kohn (Harvard) to The Jackson Laboratory by Dr. Egorov.
|Allele Name||b haplotype mutation 12|
|Allele Synonym(s)||bm12; H-2bm; H2bm12|
|Gene Symbol and Name||H2-Ab1, histocompatibility 2, class II antigen A, beta 1|
|Strain of Origin||(C57BL/6 x BALB/c)F1|
|General Note||Genbank ID for this allele: M54876|
|Molecular Note||Three non-consecutive nucleotide changes occurred, resulting in three amino acid substitutions in the beta1 exon. The amino acid changes consist of codon 67 (isoleucine to phenylalanine), codon 70 (arginine to glutamine) and codon 71 (threonine to lysine). These changes were likely the product of gene conversion of H2-Ab1b with sequence from H2-Ebb.|
The Jackson Laboratory has not developed a genotyping protocol for H2 haplotypes. The following reference may helpful: Saha BK. J Immunol Meth 1996 Jul 17;194(1):77-83. (PMID: 8690943). Alternatively, haplotype-specific antibodies can be used with FACS.
When using the bm12 mouse strain in a publication, please cite the originating article(s) and include JAX stock #001162 in your Materials and Methods section.