B2m (β2m)

Constitutive Knock Out

B2m (β2m) Constitutive Knock Out Mouse Model

C57BL/6 Background

  • Model #
  • Genotype
  • Nomenclature
  • B2MN12-F
    B6.129-B2mtm1Jae N12
  • B2MN12-M
    B6.129-B2mtm1Jae N12
  • Contains a disruption of the beta-2-microglobulin gene
  • Deficient in MHC Class I molecule expression
  • Exhibits depletion of CD8+ T cells
  • Lack the NK1.1+ CD4+ T-cell population as well, because of dependence on MHC Class 1b molecule CD1 for development
  • Useful in transplantation, gene therapy, and immunological disease research

Genetic Background:

C57BL/6 Background


The B2m mouse was developed in the laboratory of Rudolf Jaenisch at the Whitehead Institute. The model was created by targeting the B2m gene in D3 ES cells and injecting the targeted cells into C57BL/6J blastocysts. Resultant chimeras were backcrossed to C57BL/6 for five generations (N5). GenPharm International received stock from the Jaenisch lab in 1991. Taconic received stock in February 1994. The mice were then backcrossed seven generations (N12) to C57BL/6NTac and derived by embryo transfer. Heterozygotes were intercrossed to homozygosity. The colony is maintained through incrossing of homozygotes.


Wild type for Nnt mutation





Initial Publication:

Zijlstra M, Bix M, Simister NE, Loring JM, Raulet DH, Jaenisch R. (1990) β2-Microglobulin deficient mice lack CD4-8+ cytolytic T cells, Nature, 344(6268):742-746.

Conditions of Use for Taconic Transgenic Models™
Taconic Transgenic Models™ (Models) are produced and distributed under rights to patents and intellectual property licensed from various institutions. Taconic sells the Models to purchasers, grants to each purchaser a right under Taconic's rights in such licensed patents and intellectual property to use the purchased Model in consideration of purchasers' acknowledgement of and agreement to the Terms and Conditions of Sale and the following terms of use:
  • Title to these Models and biological materials derived from them remains with Taconic Biosciences, Inc.
  • The Models will be used for research purposes only.
  • The Models will not be bred except to obtain embryos or fetuses required for research purposes
  • The Models and biological materials derived from them will not be distributed to third parties or used for commercial purposes.