C57BL/6(FVB)-Igk^{tm1.1(b12)Nemz} Igh^{tm1.1(b12)Nemz}/J

Stock number: 023065
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools, Virology Research

Description

This b12HL mutant mouse strain expresses the broadly neutralizing HIV antibody b12 and may be useful in design, development and testing of potential HIV vaccines.

Detailed description

Monoclonal antibodies called broadly neutralizing antibodies, are able to interact with many different HIV isolates of various clades, inhibiting infection of target cells, and are of interest in the design and development of potential protective vaccines. These knock in b12HHLL mice express the broadly neutralizing HIV antibody b12, which recognizes the CD4 binding site on HIV envelope glycoprotein gp120. The HIV b12 antibody L and H chain variable exons replace the respective J clusters in the endogenous mouse genes, Igk and Igh. Mice that are heterozygous for the 2 targeted mutations are viable and fertile. More than 90% of B cells from mutant mice heterozygous for the mutations bind soluble HIV envelope antigen as assayed by flow cytometry. Preimmune (naive) sera from heterozygous mutant mice has high titers of HIV Env IgG binding activity. The Donating Investigator has not attempted to maintain the strain homozygous for both alleles, but reports that double homozygotes should be viable and fertile.

Development

These double mutant mice were generated by crossing the single targeted mutation strains.

For the Igk^tm1(b12)Nemz allele, b12 L-chain, a targeting vector designed by Dr. David Nemazee (The Scripps Research Institute) containing a floxed NEO cassette was used to replace the J cluster in the Igk locus with the HIV antibody b12 L chain VJ element. The construct was electroporated into C57BL/6NTac-derived iTL IC1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were tested for germline transmission. The mice were then bred to Cre recombinase expressing mice on the congenic C57BL/6J background (Stock No. 003724) to remove the floxed NEO cassette.



For the Igh^tm1(b12)Nemz allele, b12 H-chain, a targeting vector designed by Dr. David Nemazee (The Scripps Research Institute) containing a floxed NEO cassette was used to replace the DQ52-JH cluster in the Igh locus with HIV antibody b12 variable region coding sequence. The construct was electroporated into C57Bl/6-derived C2 ES cell line C57Bl/6-derived C2 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were tested for germline transmission. The mice were then bred to Cre recombinase expressing mice on the congenic C57BL/6J background (Stock No. 003724) to remove the floxed NEO cassette.

The single targeted mutation strains were crossed to generate the double mutant line (double heterozygotes). Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.

Allele

Symbol: Igh^{tm1.1(b12)Nemz}
Name: targeted mutation 1.1, David Nemazee
MGI accession ID: MGI:5505302
Generation method: Targeted
Attributes: Inserted expressed sequence
Marker symbol: Igh
Marker name: immunoglobulin heavy chain complex
Chromosome: 12
Strain of origin: C57BL/6NTac
Molecular note: A floxed neomycin resistance cassette replaced the DQ52-JH cluster in the Igh locus with HIV antibody b12 variable region coding sequence. Cre-mediated recombination removed the neomycin resistance cassette.

Allele

Symbol: Igk^{tm1.1(b12)Nemz}
Name: targeted mutation 1.1, David Nemazee
MGI accession ID: MGI:5505300
Generation method: Targeted
Attributes: Inserted expressed sequence
Marker symbol: Igk
Marker name: immunoglobulin kappa chain complex
Chromosome: 6
Strain of origin: C57BL/6NTac
Molecular note: A floxed neomycin resistance cassette replace the J cluster in the Igk locus with the HIV antibody b12 L chain VJ element. Cre-mediated recombination removed the neomycin resistance cassette.