B6N.129(Cg)-Pdcd1lg2^tm2Dmp/J

Stock number: 017515
Research areas: Cancer Research, Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

In this B7-DC KO strain, an enhanced green fluorescent protein (EGFP) replaces exon 2, including the initiation codon, of the programmed cell death 1 ligand 2 gene (Pdcd1lg2) - abolishing endogenous gene function. These mice may be useful for studying self tolerance, Th1 and Th2 immune responses.

Detailed description

In this strain, an enhanced green fluorescent protein (EGFP) and a loxP-flanked neomycin resistance (neo) cassette replace exon 2, including the initiation codon, of the programmed cell death 1 ligand 2 (Pdcd1lg2) gene, abolishing gene function. Homozygotes are viable and fertile. The Pdcd1lg2 gene encodes the costimulatory molecule B7-DC which is expressed in dendritic cells (DCs). B7-DC binds to the PD-1 immunoreceptor tyrosine-based inhibitory motif-containing receptor expressed on activated T cells where it regulates self tolerance and immune responses to microbes. These mice exhibit a reduction of intrahepatic tumor-specific CD8 T cells, interferon-γ (IFN-γ) production by CD4 T cells, IFN-γ-dependent humoral responses , antigen-specific CD8 T cell responses, and cytotoxic T lymphocyte (CTL) activity. In these mice hepatic tumors grow more quickly than in wildtype mice. GFP expression is not visible in B7-DC tissue, but the donating investigator reports that GFP expression can be observed in cultured DCs and macrophages when treated with interleukin (IL)-4 or IL-13. These mice may be useful for studying self tolerance, Th1 and Th2 immune responses.

The donating investigator reports that there is no difference in EGFP expression between mice with and without neo.

Development

A targeting vector was designed to replace exon 2, including the initiation codon, of the programmed cell death 1 ligand 2 (Pdcd1lg2) gene with an enhanced green fluorescent protein (EGFP) and a loxP-flanked neomycin resistance (neo) cassette. The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl⁺-derived R1 embryonic stem (ES) cells, and chimeras were made by ES cell aggregation. The donating investigator reported that chimeric mice were bred to CMV-Cre mice on a BALB/c background - with the intention of removing the neo cassette (genotyping later determined it retained the neo cassette). The B7-DC KO colony was backcrossed at least nine generations to BALB/c mice (and the CMV-Cre was removed). Following this, the donating investigator reported they mice were backcrossed for at least 12 generations to C57BL/6NCrl (see SNP note below), and then sent to The Jackson Laboratory. Upon arrival, mice were bred to C57BL/6NJ (Stock No. 005304) for at least one generation to establish the colony. Genotyping performed at The Jackson Laboratory determined the B7-DC KO allele retained the neo cassette from the original construct.

A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. While 1 of the 27 markers throughout the genome suggested a C57BL/6 genetic background, 3 of 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6J ; C57BL/6N genetic background.

Allele

Symbol: Pdcd1lg2^tm2Dmp
Name: targeted mutation 2, Drew M Pardoll
MGI accession ID: MGI:5427625
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Pdcd1lg2
Marker name: programmed cell death 1 ligand 2
Chromosome: 19
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Molecular note: The signal peptide containing the ATG initiation codon was replaced with EGFP and a NEO cassette. This allele was subsequently used to generate Pdcd1lg2^tm1Dmp.