B2m (β2m)

Constitutive Knockout

B2m (β2m) Constitutive Knockout Mouse Model
EZcohort® Models
The easiest way to acquire and breed cryopreserved GEMs

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
Orders by weight: Taconic cannot accept orders by weight for this model. Please note that shipments may contain animals with a larger weight variation.

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 EZcohort® Models
EZcohort® models are produced and distributed under rights to patents and intellectual property licensed from various institutions. Taconic Biosciences, Inc. (Taconic) sells EZcohort® models to purchasers, grants to each purchaser a right under Taconic's rights in such licensed patents and intellectual property to use the purchased EZcohort® models in consideration of purchasers' acknowledgement of and agreement to Taconic's Terms and Conditions for the Sale of Products and the following conditions of use:

  • Title to EZcohort® models and biological materials derived from them remains with Taconic.
  • EZcohort® models will be used for research purposes only.
  • EZcohort® models and biological materials derived from them will not be distributed to third parties or used for commercial purposes.
  • Breeders from deliverables can be used for propagation of EZcohort® models or to cross to other strains.
  • Continuation of breeding and crossbreeding of EZcohort® models outside Taconicis permitted for a term of three years post-purchase of the EZcohort® models and is subject to annual confirmation of these EZcohort® Conditions of Use.

Continuation of breeding and crossbreeding after the three year term will require renewal of the EZcohort® Conditions of Use and payment of a fee.