NOD.129S2(B6)-Cd28^tm1Mak/JbsJ

Stock number: 004761
Product name: CD28^-
Research areas: Diabetes and Obesity Research, Immunology, Inflammation and Autoimmunity Research

Description

These Cd28 knock-out mice exhibit rapid onset Type 1 diabetes in both males and females.

Detailed description

NOD mice heterozygous for the Cd28^tm1Mak mutation are viable, fertile; exhibiting diabetes onset and incidence similar to NOD. NOD mice homozygous for Cd28^tm1Mak experience rapid onset Type 1 diabetes in both males and females. When stimulated with anti-Cd3 mAB, T cells from CD28 deficient NOD mice proliferate poorly when compared with wildtype controls. Nor do T cells proliferate in culture after the mice have been immunized with ovalbumin (OVA) in complete Freunds adjuvant. The IL-2 level of T-cells from mice that have been stimulated with either anti-Cd3 or OVA was significantly reduced. However, when challenged with GAD the CD28 deficient mice produced normal levels of IL-2. RT-PCR indicates a dramatic increase in the amount of IFNgamma and decreased IL4 compared to heterozygous controls. 1.5% of CD4 T cells from homozygous mice express CD25, while 6.5% of the CD4 T cells express CD25 in their wildtype cohorts.

This model is useful for studying the CTLA4/CD28:CD80/CD86 pathways in the regulation of self tolerance and susceptibility to autoimmune diseases.

Development

Cd28, located on Chr. 1, 30.1cM, is involved in costimulatory signaling important for T cell activation. A construct containing a neomycin expression cassette replacing part of exon 2 of Cd28 was transfected into D3 (129S2/SvPas derived) embryonic stem cells (ES cells). These ES cells were injected into C57BL/6 blastocysts. As reported by Lenschow et al 1996, chimeric founders were initially mated to C57BL/6 and intercrossed to generate Cd28 deficient mice. B6 congenic mice homozygous for the mutation were subsequently mated to NOD for 4 generations, Lenschow et al 1996, prior to making homozygous. In 2006, the T1DR received mice heterozygous for the mutation at generation N11.

Allele

Symbol: Cd28^tm1Mak
Name: targeted mutation 1, Tak Mak
MGI accession ID: MGI:1857150
Generation method: Targeted
Attributes: Null/Knockout
Synonyms: CD28^-; CD28KO
Marker symbol: Cd28
Marker name: CD28 antigen
Marker synonyms: CD28RNA; Tp44
Chromosome: 1
Strain of origin: 129S2/SvPas
Molecular note: A genomic fragment containing part of exon 2 was replaced by a neomycin resistance cassette. Flow-cytometry analysis on peripheral blood lymphocytes demonstrated that the protein was not expressed in these cells in homozygous mice.