BXSB mice develop spontaneous autoimmune disease characterized by moderate lymph node and spleen enlargement, hemolytic anemia, hypergammaglobulinemia, and immune complex glomerulonephritis. The disease process in BXSB is strikingly accelerated in males, which live little more than a third as long as females. The acceleration is due to the presence of the Yaa gene on the Y chromosome. Characteristics of mice homozygous for the B2mtm1Unc targeted mutation include a lack of MHC class I protein expression on the cell surface. There are few CD8+ cytotoxic T-cells and under some circumstances a compensatory increase in CD4+ cytotoxic T-cells. Immune responses involving CD8+ T-cells are severely deficient providing a model to assess the role of CD8+ cells and class I MHC in various experimental systems. Hemachromatosis has been noted in certain genetic backgrounds (Rothenberg BE, Voland JR, Proc Natl Acad Sci USA 93:1529-34, 1996).
In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. This is the case for the strain above. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.
The B2mtm1Unc mutant strain was developed in the laboratory of Dr. Beverly Koller and Dr. Oliver Smithies at the University of North Carolina at Chapel Hill. It was generated by a targeted disruption of the B2m gene. The 129-derived E14TG2a ES cell line was used. The BXSB.129P2(B6)-B2mtm1Unc/J strain was produced in the laboratory of Dr. Derry Roopenian at The Jackson Laboratory by backcrossing the B2mtm1Unc mutation 10 times to BXSB/MpJ Yaa inbred mice.
|Allele Name||targeted mutation 1, University of North Carolina|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||b2mnull; beta2M-; beta2m0; beta2mnull; beta2mo; beta2mtm1Unc; beta2MKO; beta2-m-KO; I0; MHC-I-|
|Gene Symbol and Name||B2m, beta-2 microglobulin|
|Strain of Origin||129P2/OlaHsd|
|Molecular Note||Insertion of a neomycin-resistance gene into the second exon.|
|Mutations Made By|| |
Dr. Oliver Smithies, University of North Carolina at Chapel Hill
This B2mtm1Unc strain is maintained by mating homozygous siblings. Only homozygous mice may be ordered.
When using the BXSB β2m KO mouse strain in a publication, please cite the originating article(s) and include JAX stock #002449 in your Materials and Methods section.