Overview

Also Known As:BALB/c β₂m KO

These B2m knock-out mice exhibit little if any MHC class I protein expression on the cell surface.

Donating Investigator

Derry Roopenian, The Jackson Laboratory

Genetic overview

Genetic Background	Generation
000651 BALB/cJ

B2m^tm1Unc

Allele Type	Gene Symbol	Gene Name
Targeted (Null/Knockout)	B2m	beta-2 microglobulin

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Research Applications

Research Tools
Metabolism Research
Hematological Research
Internal/Organ Research
Immunology, Inflammation and Autoimmunity Research

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Base Price

Starting at:

$2,854.50 Domestic price Cryo Recovery

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Details

Detailed Description

Mice homozygous for the B2m^tm1Unc targeted mutation have little if any MHC class I protein expression on the cell surface. There are few CD8⁺ cytotoxic T-cells and under some circumstances a compensatory increase in CD4⁺ cytotoxic T-cells. Immune responses involving CD8⁺ T-cells are severely deficient providing a model to assess the role of CD8⁺ cells and class I MHC in various experimental systems. Other traits of B2M deficient mice include: NK cells deficiency, NK1⁺ T cells deficiency and decreased levels of serum Ig. Some forms of lupis autoimmunity are severely reduced. (Christianson, J Immunol 156:4932-9, 1996). Hemachromatosis has been noted in certain genetic backgrounds (Rothenberg BE, Voland JR, Proc Natl Acad Sci USA 93:1529-34, 1996). In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. This is the case for the strain above. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.

Development

The B2m^tm1Unc mutant strain was developed in the laboratory of Dr. Beverly Koller and Dr. Oliver Smithies at the University of North Carolina at Chapel Hill. It was generated by a targeted disruption of the B2m gene. The 129-derived E14TG2a ES cell line was used. The BALB/cJ strain was produced in the laboratory of Dr. Derry Roopenian at The Jackson Laboratory by backcrossing the B2m^tm1Unc mutation 9 times to BALB/cJ inbred mice.

Control Suggestions

000651 BALB/cJ

Additional Information

Considerations for Choosing Controls

Selected References

Koller BH; Marrack P; Kappler JW; Smithies O. 1990. Normal development of mice deficient in beta 2M, MHC class I proteins, and CD8+ T cells. Science 248(4960):1227-30PubMed: 2112266 MGI: J:64451

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Genetics

B2m^tm1Unc

Allele Symbol: B2m^tm1Unc

Allele Name	targeted mutation 1, University of North Carolina
Allele Type	Targeted (Null/Knockout)
Allele Synonym(s)	b2m^null; beta2M-; beta2m⁰; beta2m^null; beta2m^o; beta2m^tm1Unc; beta2MKO; beta2-m-KO; I⁰; MHC-I^-
Gene Symbol and Name	B2m, beta-2 microglobulin
Gene Synonym(s)
Strain of Origin	129P2/OlaHsd
Chromosome	2
Molecular Note	Insertion of a neomycin-resistance gene into the second exon.
Mutations Made By	Dr. Oliver Smithies, University of North Carolina at Chapel Hill

Disease/Phenotype

Disease Terms

Research Areas By Phenotype

This mouse can be used to support research in many areas including:

Genotype: B2m^tm1Unc related

Research Tools
- Immunology, Inflammation and Autoimmunity Research
  - MHC class I deficiency
Metabolism Research
- Hemochromatosis
  - iron metabolism defects
Hematological Research
- Anemia, Iron Deficiency and Transport Defects
  - hemochromatosis
Internal/Organ Research
- Liver Defects
  - hemochromatosis
Immunology, Inflammation and Autoimmunity Research
- Immunodeficiency
  - MHC class I deficiency

Mammalian Phenotype Terms by Genotype

The following phenotype information is associated with a similar, but not exact match to this JAX^® Mice strain

Genotype: B2m^tm1Unc/B2m^tm1Unc
B6.129P2-B2m/DcrJ

endocrine/exocrine gland phenotype

abnormal pancreas morphology
- mice develop peri-islet T cell aggregates >30 weeks of age

immune system phenotype

increased susceptibility to infection induced morbidity/mortality
- following infection with either a low or high dose of IOE, 90% of mice survive a low dose and all mice succumb to a high dose

abnormal tumor necrosis factor level
- following infection with a lethal low dose of a monocytotropic Ehrlichia bacteria from Ixodes ovatrus ticks (IOE), induces less TNF-alpha than in infected wild-type mice

abnormal interleukin level
- following infection with a lethal low dose of a monocytotropic Ehrlichia bacteria from Ixodes ovatrus ticks (IOE), induces less IL-10 than in infected wild-type mice

decreased susceptibility to autoimmune diabetes
- when splenocytes from diabetic donors are transferred into lethally-irradiated 8-week old recipients, female mice remain normoglycemic for about 17 weeks before developing hyperglycemia/diabetes; kinetics are much slower than in B2m-null, Tg(GFAP-B2m)Mdos (line 9 or 14) transgenic mice
- (line 9 or 14) transgenic mice
- mice do not develop spontaneous diabetes compared to wild-type NOD controls

decreased susceptibility to bacterial infection
- at day 12 and 14 post-infection with a lethal low dose of IEO, mice exhibit only mild liver pathology, few apoptotic foci in the liver and preserved lymphoid tissue cellularity
- to a high dose
- mice are highly resistant to infection with a monocytotropic Ehrlichia bacteria from Ixodes ovatrus ticks (IOE) following infection with either a low or high dose of IOE, 90% of mice survive a low dose with mild illness and all mice succumb to a high dose
- mice have lower burdens of Ehrlichia bacteria in the lungs and spleen following infection than do wild-type mice
- following infection with IEO, CD8+ T cells in the spleen are reduced (1.5%+/-0.1% of splenocytes compared to 9.7%+/-0.7% of splenocytes in wild-type mice)

increased IgM level

decreased CD8-positive, alpha-beta T cell number
- following infection with a monocytotropic Ehrlichia bacteria from Ixodes ovatrus ticks (IOE), CD8+ T cells in the spleen are reduced (1.5%+/-0.1% of splenocytes compared to 9.7%+/-0.7% of splenocytes in wild-type mice)
- in uninfected mice the number of CD8+ T cells in the spleen is reduced compared to in wild-type mice

decreased IgG level

increased T-helper 1 cell number
- following infection with a monocytotropic Ehrlichia bacteria from Ixodes ovatrus ticks (IOE), the number of interferon-gamma producing CD4+ Th1 cells in the spleen on day 8 and day 12 is increased relative to in infected wild-type mice

mortality/aging

increased susceptibility to infection induced morbidity/mortality
- following infection with either a low or high dose of IOE, 90% of mice survive a low dose and all mice succumb to a high dose

hematopoietic system phenotype

decreased CD8-positive, alpha-beta T cell number
- in uninfected mice the number of CD8+ T cells in the spleen is reduced compared to in wild-type mice
- following infection with a monocytotropic Ehrlichia bacteria from Ixodes ovatrus ticks (IOE), CD8+ T cells in the spleen are reduced (1.5%+/-0.1% of splenocytes compared to 9.7%+/-0.7% of splenocytes in wild-type mice)

increased IgM level

increased T-helper 1 cell number
- following infection with a monocytotropic Ehrlichia bacteria from Ixodes ovatrus ticks (IOE), the number of interferon-gamma producing CD4+ Th1 cells in the spleen on day 8 and day 12 is increased relative to in infected wild-type mice

decreased IgG level

homeostasis/metabolism phenotype

abnormal interleukin level
- following infection with a lethal low dose of a monocytotropic Ehrlichia bacteria from Ixodes ovatrus ticks (IOE), induces less IL-10 than in infected wild-type mice

decreased circulating serum albumin level

abnormal tumor necrosis factor level
- following infection with a lethal low dose of a monocytotropic Ehrlichia bacteria from Ixodes ovatrus ticks (IOE), induces less TNF-alpha than in infected wild-type mice

Genotype: B2m^tm1Unc/B2m^tm1Unc
involves: 129P2/OlaHsd * C57BL/6

hematopoietic system phenotype

abnormal T cell number
- when wild-type bone marrow is transferred into these mice, MAIT T cells are found in the gut
- mucosal-associated invariant T cells (MAIT) that express the canonical mVa19-Ja33 TCR rearrangement and are typically found in the gut lamina propia are virtually absent in these mice
- when these mice serve as bone marrow donors, MAIT T cells are absent in the gut of irradiated hosts

absent CD8-positive, alpha-beta T cells
- deficient in CD4-CD8+ T cells
- CD8+CD4- T cells from the thymus of five week old mice are almost non-existent in comparison to control (0.8% vs. 6.7%), however, total numbers of alpha beta T cells and CD8-CD4+ T cells do not differ significantly from control

immune system phenotype

abnormal T cell number
- when these mice serve as bone marrow donors, MAIT T cells are absent in the gut of irradiated hosts
- mucosal-associated invariant T cells (MAIT) that express the canonical mVa19-Ja33 TCR rearrangement and are typically found in the gut lamina propia are virtually absent in these mice
- when wild-type bone marrow is transferred into these mice, MAIT T cells are found in the gut

absent CD8-positive, alpha-beta T cells
- CD8+CD4- T cells from the thymus of five week old mice are almost non-existent in comparison to control (0.8% vs. 6.7%), however, total numbers of alpha beta T cells and CD8-CD4+ T cells do not differ significantly from control
- deficient in CD4-CD8+ T cells

decreased level of surface class I molecules
- surface expression of class I molecules in cells from lymph nodes, spleen and thymus cannot be detected by flow cytometry

Genotype: B2m^tm1Unc/B2m⁺
involves: 129P2/OlaHsd * C57BL/6

hematopoietic system phenotype

decreased CD8-positive, alpha-beta T cell number
- numbers of CD8+CD4- T cells from the thymus of five week old mice are reduced in comparison to control (4.9% vs. 6.7%), however, in peripheral lymphoid tissues numbers of CD8+CD4- T cells do not differ from control

immune system phenotype

decreased level of surface class I molecules
- surface expression of class I molecules in cells from lymph nodes are reduced in comparison to control

decreased CD8-positive, alpha-beta T cell number
- numbers of CD8+CD4- T cells from the thymus of five week old mice are reduced in comparison to control (4.9% vs. 6.7%), however, in peripheral lymphoid tissues numbers of CD8+CD4- T cells do not differ from control

References

Koller BH; Marrack P; Kappler JW; Smithies O. 1990. Normal development of mice deficient in beta 2M, MHC class I proteins, and CD8+ T cells. Science 248(4960):1227-30PubMed: 2112266 MGI: J:64451

Additional - B2m^tm1Unc related

Technical Support

CONTACT TECHNICAL SUPPORT

Genotyping Protocols
- Standard PCR:B2m
- Standard PCR:B2m
- Genotyping resources and troubleshooting
Breeding Considerations

When held in a live colony, this B2m^tm1Unc strain was maintained by mating homozygous siblings. Expected coat color from breeding:Albino
- Additional Breeding and Husbandry Support
Appearance
- albino
  Related Genotype: Tyr^c/Tyr^c
Citation
When using the BALB/c β₂m KO mouse strain in a publication, please cite the originating article(s) and include JAX stock #002420 in your Materials and Methods section.

Animal Health Reports

Facility Barrier Level Descriptions

Production of mice from cryopreserved embryos or sperm occurs in a maximum barrier room, G200

Pricing & Availability

Cryo Recovery

Domestic
International

Live Mouse

Age

Genotype

Price

weeks

Cryorecovery - Pricing

Service/Product	Description	Price
> >	Heterozygous or Wildtype for B2m<tm1Unc>

Related Products and Services

Frozen Mouse Embryo	C.129P2(B6)-B2m<tm1Unc>/J	$2595.00
Frozen Mouse Embryo	C.129P2(B6)-B2m<tm1Unc>/J	$2595.00
Frozen Mouse Embryo	C.129P2(B6)-B2m<tm1Unc>/J	$3373.50
Frozen Mouse Embryo	C.129P2(B6)-B2m<tm1Unc>/J	$3373.50

Payment Terms and Conditions

Terms are granted by individual review and stated on the customer invoice(s) and account statement. These transactions are payable in U.S. currency within the granted terms. Payment for services, products, shipping containers, and shipping costs that are rendered are expected within the payment terms indicated on the invoice or stated by contract. Invoices and account balances in arrears of stated terms may result in The Jackson Laboratory pursuing collection activities including but not limited to outside agencies and court filings.

The Jackson Laboratory's Genotype Promise

The Jackson Laboratory has rigorous genetic quality control and mutant gene genotyping programs to ensure the genetic background of JAX® Mice strains as well as the genotypes of strains with identified molecular mutations. JAX® Mice strains are only made available to researchers after meeting our standards. However, the phenotype of each strain may not be fully characterized and/or captured in the strain data sheets. Therefore, we cannot guarantee a strain's phenotype will meet all expectations. To ensure that JAX® Mice will meet the needs of individual research projects or when requesting a strain that is new to your research, we suggest ordering and performing tests on a small number of mice to determine suitability for your particular project. We do not guarantee breeding performance and therefore suggest that investigators order more than one breeding pair to avoid delays in their research.

Terms Of Use

General Terms and Conditions

Questions about Terms of Use

Licensing Information

Phone: 207-288-6470

Email: TechTran@jax.org

Also Known As:BALB/c β2m KO

Donating Investigator

Genetic overview

Research Applications

Base Price

Detailed Description

Development

Control Suggestions

Additional Information

Selected References

B2mtm1Unc

Allele Symbol: B2mtm1Unc

Disease Terms

Research Areas By Phenotype

This mouse can be used to support research in many areas including:

Genotype: B2mtm1Unc related

Mammalian Phenotype Terms by Genotype

Genotype: B2mtm1Unc/B2mtm1UncB6.129P2-B2m/DcrJ

endocrine/exocrine gland phenotype

immune system phenotype

mortality/aging

hematopoietic system phenotype

homeostasis/metabolism phenotype

Genotype: B2mtm1Unc/B2mtm1Uncinvolves: 129P2/OlaHsd * C57BL/6

hematopoietic system phenotype

immune system phenotype

Genotype: B2mtm1Unc/B2m+involves: 129P2/OlaHsd * C57BL/6

hematopoietic system phenotype

immune system phenotype

References

Additional - B2mtm1Unc related

Genotyping Protocols

Breeding Considerations

Appearance

Citation

Animal Health Reports

Production of mice from cryopreserved embryos or sperm occurs in a maximum barrier room, G200

Live Mouse

Cryorecovery - Pricing

Related Products and Services

Payment Terms and Conditions

The Jackson Laboratory's Genotype Promise

Terms Of Use

Licensing Information

Also Known As:BALB/c β₂m KO

B2m^tm1Unc

Allele Symbol: B2m^tm1Unc

Genotype: B2m^tm1Unc related

Genotype: B2m^tm1Unc/B2m^tm1Unc
B6.129P2-B2m/DcrJ

Genotype: B2m^tm1Unc/B2m^tm1Unc
involves: 129P2/OlaHsd * C57BL/6

Genotype: B2m^tm1Unc/B2m⁺
involves: 129P2/OlaHsd * C57BL/6

Additional - B2m^tm1Unc related