B6.Cg-Pepc^b Ptprc^a Tg(UBC-scFv)2Nemz/J

Stock number: 006259
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

These "kappa-macroself Ag#2" transgenic mice may be useful to study B cell receptor editing, B cell tolerance in polyclonal immune systems, and for the rapid screening of mutants of interest for potential defects in B cell tolerance.

Detailed description

"Kappa-macroself Ag#2" transgenic mice express a membrane-bound "macroself" superantigen with specificity for the mouse immunoglobulin kappa light chain (IgΚ). Hemizygous mice are viable and fertile. The transgene is expressed in virtually all cells tested, including lymphoid tissue and bone marrow. B cells expressing the IgΚ-macroself superantigen are absent from the peripheral lymphoid organs while Igl⁺ B cell numbers are substantially increased. Although bone marrow B cell numbers are unchanged, total peripheral B cell populations are reduced by approximately one half. These mice also express the CD45.1 (Ly5.1 or Ptprca) allele, which is atypical for this C57BL/6 (B6) congenic background, and this marker may be used to track donor cell populations in bone marrow transplantation studies with B6 (CD45.2: Ptprc^b) mice. These "kappa-macroself Ag#2" transgenic mice may be useful to study B cell receptor editing and B cell tolerance in a polyclonal immune system, and to rapidly screen other mutations for potential defects in B cell tolerance.

Genotyping Note: As the transgene expresses a superantigen reactive to immunoglobulin kappa of mouse and may interfere with antibody specificity if using mouse anti-CD45 antibodies, a pre-blocking step using unlabeled mouse IgG:kappa (or equivalent blocking step) is recommended for FACS-typing of the Ptprc (CD45) allele.

Development

These mice are designed to express a membrane-tethered single-chain variable fragment antibody with specificity to mouse IgΚ light chain. The 4 kb Ulik transgene contains the 1.2 kb human ubiquitin C promoter, rheumatoid factor Ig light chain gene leader exon and first intron, the expressed variable genes from the rat anti-mouse Ig CΚ hybridoma 187 line, the hinge, CH2, and CH3 sequences from rat IgG1 heavy chain cDNA, and the transmembrane and intracytoplasmic sequences from the mouse H2-k^b gene. This construct was microinjected into (B6xDBA/2)F1 embryos and then implanted into pseudopregnant Igk-deficient foster dams. "Kappa-macroself" transgenic mice (founder line 2) were backcrossed to mice on a "B6.CD45.1" background (derived from Stock No. 002014, B6.SJL-Ptprc^a Pepc^b/BoyJ) for approximately 20 generations before arriving at The Jackson Laboratory.

Allele

Symbol: Pepc^b
Name: b variant
MGI accession ID: MGI:4819861
Generation method: Not Applicable
Marker symbol: Pepc
Marker name: peptidase C
Chromosome: 1
Strain of origin: Not Applicable
Molecular note: The Pepc gene controls electrophoretic variation of peptidase C (PEP-C; EC 3.4.11.-) of red blood cells. The allele Pepc^b determines a faster migrating band and is found in the CBA/J and A/He strains.

Allele

Symbol: Ptprc^a
Name: a variant
MGI accession ID: MGI:4819849
Generation method: Not Applicable
Marker symbol: Ptprc
Marker name: protein tyrosine phosphatase, receptor type, C
Chromosome: 1
Strain of origin: Not Applicable
Site of expression: Widely expressed on all adaptive and innate immune cells.
Molecular note: Ptprc^a is found in strains SJL/J, STS/A, and DA. Ptprc^b is found in strains C57BL/6, C3H/An, DBA/2, AKR, and many others (J:13367, J:12054, J:12077, J:8603). Twelve nucleotide differences between the a and b alleles have been identified. These base substitutions correspond to five amino-acid changes within the extracellular domain of the encoded protein. These amino-acid differences are clustered in a region that also contains the greatest divergence between mouse and rat sequences (J:22485).

Note that the allele designations originally described were reversed in 1987 (J:8603); all publications prior to 1987 show SJL/J, STS/A, and DA as having the b allele and the C57BL/6J group as having the a allele (J:22341).

Allele

Symbol: Tg(UBC-scFv)2Nemz
Name: transgene insertion 2, David Nemazee
MGI accession ID: MGI:3760426
Generation method: Transgenic
Attributes: Inserted expressed sequence
Marker symbol: Tg(UBC-scFv)2Nemz
Marker name: transgene insertion 2, David Nemazee
Chromosome: UN
Strain of origin: (C57BL/6 x DBA/2)F1
Expressed genes: scFv,single chain variable fragment,
Molecular note: These mice are designed to express a membrane-tethered single chain variable fragment antibody with specificity to mouse Igk light chain. The 4 kb "Ulik" transgene contained the 1.2 kb human ubiquitin C promoter, rheumatoid factor Ig light chain gene leader exon and first intron, the expressed variable genes from the rat anti-k hybridoma 187 line, the hinge, CH2, and CH3 sequences from rat gamma chain 1 (CH1 domain deleted), and the transmembrane and intracytoplasmic sequences from the H2-kb gene.