JAX NOTES: Toll-like Receptor JAX® Mice for Immunological Research

Toll-like Receptor JAX® Mice for Immunological Research

JAX^® NOTES Issue 498, Summer 2005

Mice with mutations in either toll-like receptors (TLRs) or genes involved in TLR pathways have played and will continue to play an important role in the research of innate and adaptive immunity.¹ TLRs are pattern recognition receptors that respond to unique microbial molecular motifs called pathogen associated molecular patterns (PAMPs). Examples of PAMPs are lipopolysaccharide (LPS) from gram negative bacteria, peptidoglycans from both Gram-negative and Gram-positive bacteria, and unmethylated CpG (see Table 1 for list of mouse Tlrs, chromosome locations and physical positions, and ligands). When PAMPs ligate to macrophage and dendritic cell TLRs, they initiate intracellular signaling cascades that activate NF-kB and elicit pro-inflammatory responses. In 1997, a human TLR receptor (now called TLR4) was shown to induce the expression of genes involved in inflammatory responses.² A year later, two research groups independently cloned Tlr4 in the LPS non-responsive C3H/HeJ mouse strain.^3,4 Since then, research involving C3H/HeJ and other mouse models has demonstrated that Tlr and related genes likely regulate early innate immune responses to both bacterial and viral pathogens. To date, the mammalian TLR family consists of at least 12 members (Table 1).^5,6

Table 1.

Receptor	Chr⁶	Physical Positions⁶ (mb)	Ligands⁷
Tlr1	5	65	Heterodimerizes with Tlr2 to recognize triacyl lipopeptides
Tlr2	3	84	Many microbial components, including lipoproteins from various pathogens (heterodimerizes with Tlr1 to recognize triacyl lipopeptides and with Tlr6 to recognize diacyl lipopolypeptides), peptidoglycan from gram positive bacteria, glycophosphatidylinositol (GPI) anchors from malaria-causing parasites, zymosan from fungi, and forms of LPS structurally distinct from those recognized by Tlr4.
Tlr3	8	44	Viral components, double stranded RNA
Tlr4	4	65	LPS, F protein, heat shock protein (HSP) 60(?), HSP 70 (?), fibrinogen (?), fibronectins (?), hyaluronic acid fragments (?)
Tlr5	1	183	Flagellin (a constituent of bacterial flagella)
Tlr6	5	63	Heterodimerizes with Tlr2 to recognize diacyl lipopolypeptides
Tlr7	X	157.45	Viral ssRNA and DNA
Tlr8	X	157.4	Viral components
Tlr9	9	106	Viral ssRNA and DNA
Tlr10	na	na	na
Tlr11	14	43	na
Tlr12	4	127	na

^6,7 (see references); na: not available; ?: data in dispute⁷

JAX Tlr mutants

We maintain strains with Tlr2, Tlr3, and Tlr4 mutations, and several strains with mutations of genes involved in TLR signaling pathways.

Tlr mutants

Tlr2 - B6.129-Tlr2^tm1Kir/J
(Stock Number 004650)

Homozygotes for the Tlr2^tm1Kir mutation are viable, normal-sized and display neither gross physical nor behavioral abnormalities. They produce no gene product (protein). Although bone marrow derived macrophages do not respond to spirochete (Borrelia burgdorferi) lipoprotein challenge, they are activated by non-lipoprotein sonicate. Arthritis due to B. burgdorferi infection is more severe in mutants than in controls. Tissues of infected mutants can contain up to 100 times more bacteria than do those found of wild-type littermates. Elevated spirochete numbers persist eight weeks post-infection. Homozygotes produce neither TNF nor IL6, and do not become ill when treated with leptospiral (Leptospira interrogans) LPS. This strain may be useful for studying responses to bacterial endotoxins. This strain is available at the standard supply level of Repository-Live. No age specifications are accepted. The colony is sized to produce minimal quantities (typically up to six mice) upon order receipt (one order per strain). Expected delivery is 1-3 months. Larger quantities and custom orders can be arranged upon request.

Tlr3 - B6;129S1-Tlr3^tm1Flv/J
(Stock Number 005217)

Homozygotes for the Tlr3^tm1Flvtargeted mutation are viable, fertile, normal-sized and display neither gross physical nor behavioral abnormalities. They produce a truncated non-functional gene product. When challenged with poly(I:C), polyinosine-polycytidylic acid, a synthetic dsRNA analog, their macrophages produce no inflammatory cytokines, IFN-alpha and IFN-beta1. They are resistant to poly(I:C) induced shock and produce reduced levels of IL12. Their splenocytes do not respond to viral dsRNA and produce reduced quantities of IL6. This strain is currently under development. To register your interest in, go to the strain data sheet and select the link to the strain interest form in the Price and Supply Information section.

Tlr4 - C3H/HeJ
(Stock Number 000659)

A spontaneous mutation, Tlr4^Lps-d, in the toll-like receptor gene of the C3H/HeJ strain renders it endotoxin-resistant. Consequently, it is highly susceptible to infection by Gram-negative bacteria such as Salmonella enterica. When infected with Salmonella, C3H/HeJ mice exhibit delayed chemokine production, impaired nitric oxide (NO) generation, and attenuated cellular immune responses. Infected mice seem to die from enhanced bacterial growth within the liver Kupffer cell network.

Additionally, the C3H/HeJ strain is homozygous for an inversion (named In(6)1J) on Chromosome 6. The inversion covers 20% of the chromosome, between D6Mit124 (~30.3 cM) and D6Mit150 (~51.0 cM), and has no apparent effect on phenotype. Results from screening C3H substrains and cryopreserved C3H/HeJ stock suggest that the mutation arose after 1952.⁸ This strain is readily available.

Tlr4 - C.C3-Tlr4^Lps-d/J
(Stock Number 002930)

This strain is congenic both for the Tlr4^Lps-d and the Chromosome 7 tyrosinase alleles of the C3H/HeJ strain. It is a tool for analyzing markers in the tyrosinase allele region and the function of Lps^din the BALB/cJ strain, which is susceptible to infection and neoplastic disease (including the induction of plasmacytomas and other tumors). This strain is available at the standard supply level of Level 3. The colony is sized for an average order of 5-15 mice. Larger quantities and custom orders can be arranged upon request. Age range is recommended.

Tlr4 - C57BL/10ScNJ
(Stock Number 003752)

C57BL/10ScNJ mice have a deletion, Tlr4^lps-del, of the Tlr4 gene and thus are not stimulated by LPS. Their Tlr4^lps-del mutation differs from the Tlr4^Lps-d mutation of C3H/HeJ mice, which is a point mutation and causes an amino acid substitution. The allele for normal LPS response, Tlr4^lps-n, occurs in most other C3H and C57BL/10 substrains and most other mouse strains.

The breeder pair of C57BL/10ScN mice obtained from NIH and progenitors for all C57BL/10ScNJ mice at The Jackson Laboratory were tested for the spontaneous Il12rb2 mutation described by Poltorak et al.⁸ and found to carry only the wild-type Il12rb2 allele. This strain is available at the standard supply level of Repository-Live. No age specifications are accepted. The colony is sized to produce minimal quantities (typically up to 6 mice) upon order receipt (one order per strain). Expected delivery is 1-3 months. Larger quantities and custom orders can be arranged upon request.

Tlr-related mutants

B6;129S1-Map2k4^tm1Liz/J
(Stock Number 003666)

B6.129S-Cd14^tm1Frm/J
(Stock Number 003726)

B6;129P2-Nfkb1^tm1Bal/J
(Stock Number 002849)

B6;129S4-Nfkbia^tm1Bal/J
(Stock Number 002850)

Tlr and Tlr-related mutants not maintained at The Jackson Laboratory

Below is a list of Tlr-related strains we do not distribute but which may be helpful in your research. They were found by searching Mouse Genome Informatics.

Irak1^tm1Jth
Prkr^tm1Cwe
Prkr^tm1Jcbe
Traf6^tm1Mak
Sitpec^tm1Gho
Map3k14^tm1Rds
Chuk^tm1Mka
Chuk^tm2Mka
Ikbkb^tm1Cgn
Ikbkg^tm1Mak
Mapk14^tm1Mms
Mapk8^tm1Wag

References:

¹Buer J, Balling R. 2003. Mice, microbes and models of infection. Nat Rev Genet 4:195-205.

²Medzhitov R, Preston-Hurlburt P, Janeway CA Jr. 1997. A human homologue of the Drosophila Toll protein signals activation of adaptive immunity. Nature 388:94.

³Poltorak A, He X, Smirnova I, Liu MY, Van Huffel C, Du X, Birdwell D, Alejos E, Silva M, Galanos C, Freudenberg M, Ricciardi-Castagnoli P, Layton B, Beutler B. 1998. Defective LPS signaling in C3H/HeJ and C57BL/10ScCr mice: mutations in Tlr4 gene. Science 282:2085-8.

⁴Qureshi ST, Lariviere L, Leveque G, Clermont S, Moore KJ, Gros P, Malo D. 1999. Endotoxin-tolerant mice have mutations in Toll-like receptor 4 (Tlr4). J Exp Med 189:615-25.

⁵Takeda A. 2005. Toll-like receptors in innate immunity. International Imm 17:1-14.

⁶UCSC Genome Bioinformatics

⁷Dunne A, O'neill L. 2005. Adaptor usage and Toll-like receptor signaling specificity. FEBS Lett 2005 Apr 26 [Epub ahead of print].

⁸JAX Notes™. 2003. Chromosomal inversion discovered in C3H/HeJ Mice. JAX Notes™ 491:15.

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