This Tlr2 knockout strain is useful in studies of mucosal immune responses and host response to bacterial endotoxins.
Terry D. Connell, University of Buffalo
The toll-like receptor 2 protein, TLR2, which is expressed predominantly in peripheral blood leukocytes, plays a critical role in pathogen recognition and activation of innate immunity. Specifically, TLR2 mediates host response to Gram-positive bacteria and yeast via stimulation of NF-kappaB.
Mice that are homozygous for this targeted mutation of the Tlr2 gene are viable and fertile. No gene product (protein) is detected by Western blot analysis of isolated peritoneal macrophages. Bone marrow derived macrophages from homozygotes on the congenic C57BL/6 background do not respond to spirochete (Borrelia burgdorferi) lipoprotein challenge, although non-lipoprotein sonicate stimulates activation. Arthritis due to B. burgdorferi infection, as assessed by rear ankle swelling, is more severe in mutant mice on the congenic C57BL/6 background. Tissues of infected B6 congenic mutants can contain up to 100 times higher bacteria levels than those found in wildtype littermates. Elevated spirochete numbers persist 8 weeks post-infection. Homozygotes on the congenic C57BL/6 background do not produce TNF-alpha or IL-6, and do not develop symptoms of illness when treated with leptospiral (Leptospira interrogans) lippolysaccharide (LPS). Homozygotes on the congenic BALB/c background display reduced dendritic cell recruitment into NALT (nasal-associated lymphoid tissue) and cervical lymph node tissue in response to antigen challenge. In comparison to wildtype BALB/c mice, homozygotes on the congenic BALB/c background do not respond to TLR2 agonists in respect to antigen uptake and expression of CCR7 by dendritic cells. Likewise, in response to antigen challenge, homozygotes on the congenic BALB/c background exhibit reduced antigen-specific CD4 T cell proliferation and dendritic cell recruitment into NALT (nasal-associated lymphoid tissue) and cervical lymph node tissue when compared to those responses in wildtype BALB/c mice.
A targeting vector containing neomycin resistance and herpes simplex virus thymidine kinase genes was used to disrupt sequence of the targeted gene encoding the C-terminus of the extracellular and part of the transmembrane domains. The construct was electroporated into 129/SvJ derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. Heterozygotes were intercrossed, and then backcrossed to C57BL/6J for 9 generations. Dr. Terry D. Connell (University of Buffalo) obtained the mice from Dr. Carsten J. Kirschning (Technical University of Munich), and then backcrossed the mice to BALB/cAnNHsd for 7 generations using a speed congenic protocol. Upon arrival at The Jackson Laboratory, the mice were crossed to BALB/cByJ (Stock No. 001026) at least once to establish the colony.
|Allele Name||targeted mutation 1, Carsten J Kirschning|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||Ly105; TLR2-|
|Gene Symbol and Name||Tlr2, toll-like receptor 2|
|Strain of Origin||129|
|Molecular Note||Sequence encoding the extracellular domain and a portion of the transmembrane domain was replaced with a neo cassette inserted by homologous recombination. Protein was undetected by Western blot analysis of peritoneal macrophages obtained from homozygous mutant mice.|
|Mutations Made By|| |
Carsten Kirschning, Technical University of Munich
When maintaining a live colony, these mice can be bred as homozygotes.
When using the TLR2- mouse strain in a publication, please cite the originating article(s) and include JAX stock #022507 in your Materials and Methods section.