129S6.Cg-Igk^tm1Fwa Igha^tm1Fwa/J

Stock number: 040901
Product name: SA271, VH1-2/LC, hVH1-2/JH2 HC; gl-VRC01LC

Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

VH1-2/LC (also called SA271 or hVH1-2/JH2 HC; gl-VRC01LC) mice express human IGHV1-2*02, human IGHJ2*01, and human IGKV3-20*01 insertions and carry a deletion of the mouse intergenic control region 1 (IGCR1) that enable testing of HIV-1 vaccines. Immunization with antigens that are designed to elicit VRC01-class broadly neutralizing antibodies permits analysis of the immune response.

Detailed description

The design of immunogens that elicit broadly reactive neutralizing antibodies (bnAbs) has been a major obstacle to HIV-1 vaccine development. One approach to assess potential immunogens is to use mice expressing precursors of human bnAbs as vaccination models. The bnAbs of the VRC01 class are derived from the IGHV1-2 immunoglobulin heavy chain and neutralize a wide spectrum of HIV-1 strains via targeting the CD4 binding site of the envelope glycoprotein gp120.

VH1-2/LC (also called SA271 or hVH1-2/JH2 HC; gl-VRC01LC) mice express human IGHV1-2*02, human IGHJ2*01, and human IGKV3-20*01 insertions and carry a deletion of the mouse intergenic control region 1 (IGCR1) that enable testing of HIV-1 vaccines. Immunization with antigens that are designed to elicit VRC01-class broadly neutralizing antibodies permits analysis of the immune response.

The VH1-2/LC mouse vaccination model allows a germline human IGHV1-2*02 segment to undergo normal V(D)J recombination and, thereby, leads to the generation of peripheral B cells that express a highly diverse repertoire of VRC01-related receptors. When sequentially immunized with modified gp120 glycoproteins designed to engage VRC01 germline and intermediate antibodies, IGHV1-2*02-rearranging mice, which also express a VRC01-antibody precursor light chain, can support the affinity maturation of VRC01 precursor antibodies into HIV-neutralizing antibody lineages.

Development

SA271 mice carry mutations in the mouse Igh (immunoglobulin heavy chain complex) gene on Chromosome 12, and the mouse Igk (immunoglobulin kappa chain complex) gene on Chromosome 6.

The Igha mutation incorporates a substitution of mouse V_H81X (IGHV5-2) with human IGHVH1-2*02, a deletion of the intergenic control region 1 (IGCR1), and a replacement of mouse J_H1-4 with human JH2 (J_Hb; IGHJ2*01). The Igk mutation incorporates a replacement of mouse Jκ1-5 with germline-reverted VRC01 light chain (VRC01LC) IGKV3-20*01. This Igk variable region exon is composed of germline human IGKV3-20*01 and includes a 5-amino acid complementarity-determining region (CDR) L3 derived from the mature VRC01 antibody.

The human IGVH1-2*02 insertion, IGCRI deletion, and human IGHJ2*01 insertion were introduced into the Igha (IgH^a) allele of 129S/SvEv x C57BL/6-derived EF1 embryonic stem (ES) cells. The VRC01 light chain (VRC01LC, IGKV3-20*01) was integrated into one of the Igk alleles of the same ES cell clone. The ES cells were injected into Rag2 knock-out blastocysts to generate chimeric mice. The donating investigator reported that the strain was initially backcrossed to both 129S6/SvEvTac and C57BL/6, then backcrossed to 129S6/SvEvTac for an unknown number of generations over a period of 3 years prior to sending agouti males to The Jackson Laboratory in 2025. These mice do not carry a targeted knock-out of Rag2. Upon arrival, sperm was cryopreserved. When researchers order this strain via cryorecovery, they should specifically instruct which genetic background oocytes they wish to have fertilized (e.g., Stock No. 002448 or Stock No. 000664 C57BL/6J, etc).

In 2025, a SNP (single nucleotide polymorphism) panel analysis, with 43 markers covering all 19 chromosomes and the X chromosome (previously shown to match for 129S6/SvEvTac isogenic mice and Stock No. 002448 129S1/SvImJ mice), as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the males sent to The Jackson Laboratory. This showed all markers as 129S1 allele-type. These data suggest that the mice sent to The Jackson Laboratory (and used to freeze sperm in 2025) were on a 129S genetic background.

Allele

Symbol: Igk^tm1Fwa
Name: targeted mutation 1, Frederick W Alt
MGI accession ID: MGI:8243938
Generation method: Targeted
Attributes: Not Applicable
Marker symbol: Igk
Marker name: immunoglobulin kappa chain complex
Marker synonyms: kappa
Chromosome: 6
Strain of origin: 129S/SvEv x C57BL/6
Molecular note: The targeted mutation incorporates a replacement of mouse Jkappa;1-5 with germline-reverted VRC01 light chain (VRC01LC) IGKV3-20*01. This Igk variable region exon is composed of germline human IGKV3-20*01 and includes a 5-amino acid complementarity-determining region (CDR) L3 derived from the mature VRC01 antibody into the IgK locus. The VRC01 light chain (VRC01LC, IGKV3-20*01) was integrated into one of the Igk alleles of ES cell clone which incorporated the Igha^tm1Fwa.

Allele

Symbol: Igha^tm1Fwa
Name: targeted mutation 1, Frederick W Alt
MGI accession ID: MGI:8243937
Generation method: Targeted
Attributes: Not Applicable
Marker symbol: Igha
Marker name: immunoglobulin heavy constant alpha
Marker synonyms: IgA; IgA1; Igh-2
Chromosome: 12
Strain of origin: 129S/SvEv x C57BL/6
Molecular note: The targeted mutation incorporated a substitution of mouse V)H(81X (IGHV5-2) with human IGHVH1-2*02, a deletion of the intergenic control region 1 (IGCR1), and a replacement of mouse J)H(1-4 with human JH2 (J)H(b; IGHJ2*01) in Igha locus. The human IGVH1-2*02 insertion, IGCRI deletion, and human IGHJ2*01 insertion were also introduced into the Igha locus.