TLR2 Mouse
Description
TLR2 Mouse Recombinant produced in Sf9 Baculovirus cells is a single, glycosylated polypeptide chain containing 805 amino acids (25-587a.a.) and having a molecular mass of 90.7kDa. (Molecular size on SDS-PAGE will appear at approximately 70-100kDa).
TLR2 is expressed with a 239 amino acid hIgG-His tag at C-Terminus and purified by proprietary chromatographic techniques.
Product Specs
Toll-like receptor 2 (TLR2) is a key player in the immune system's ability to recognize and respond to pathogens. It is part of a family of proteins called Toll-like receptors (TLRs), which are evolutionarily conserved and share similar structures and functions. TLRs identify specific molecules associated with pathogens, known as pathogen-associated molecular patterns (PAMPs). Upon recognizing PAMPs, TLRs trigger the production of signaling molecules called cytokines, which are essential for mounting an effective immune response. Different TLRs are expressed on various cell types, and TLR2 is primarily found on immune cells like peripheral blood leukocytes. TLR2 specifically recognizes components of Gram-positive bacteria and yeast, leading to the activation of the NF-kappaB pathway, a crucial signaling pathway in immune responses.
Recombinant TLR2 protein, derived from mice, is produced using Sf9 insect cells infected with a baculovirus expression system. This process generates a single, glycosylated polypeptide chain containing 805 amino acids (specifically, amino acids 25 to 587). The resulting TLR2 protein has a molecular weight of 90.7 kDa. However, due to glycosylation, it appears as a band between 70-100 kDa on SDS-PAGE. For purification and detection purposes, a 239 amino acid human IgG-His tag is fused to the C-terminus of the protein. Proprietary chromatographic techniques are employed to purify the TLR2 protein.
The TLR2 protein is provided as a solution at a concentration of 0.25 mg/ml. The solution is prepared in Phosphate Buffered Saline (PBS) with a pH of 7.4 and contains 10% glycerol.
Adding a carrier protein like HSA or BSA (0.1%) is recommended for long-term storage.
Avoid repeated freezing and thawing cycles.
The purity of TLR2 protein is greater than 85%, as determined by SDS-PAGE analysis.
Toll-like receptor 2, CD282.
Sf9, Baculovirus cells.
ADLQESLSCD ASGVCDGRSR SFTSIPSGLT AAMKSLDLSF NKITYIGHGD LRACANLQVL MLKSSRINTI EGDAFYSLGS LEHLDLSDNH LSSLSSSWFG PLSSLKYLNL MGNPYQTLGV TSLFPNLTNL QTLRIGNVET FSEIRRIDFA GLTSLNELEI KALSLRNYQS QSLKSIRDIH HLTLHLSESA FLLEIFADIL SSVRYLELRD TNLARFQFSP LPVDEVSSPM KKLAFRGSVL TDESFNELLK LLRYILELSE VEFDDCTLNG LGDFNPSESD VVSELGKVET VTIRRLHIPQ FYLFYDLSTV YSLLEKVKRI TVENSKVFLV PCSFSQHLKS LEFLDLSENL MVEEYLKNSA CKGAWPSLQT LVLSQNHLRS MQKTGEILLT LKNLTSLDIS RNTFHPMPDS CQWPEKMRFL NLSSTGIRVV KTCIPQTLEV LDVSNNNLDS FSLFLPRLQE LYISRNKLKT LPDASLFPVL LVMKIRENAV STFSKDQLGS FPKLETLEAG DNHFVCSCEL LSFTMETPAL AQILVDWPDS YLCDSPPRLH GHRLQDARPS VLECHQLEPK SCDKTHTCPP CPAPELLGGP SVFLFPPKPK DTLMISRTPE VTCVVVDVSH EDPEVKFNWY VDGVEVHNAK TKPREEQYNS TYRVVSVLTV LHQDWLNGKE YKCKVSNKAL PAPIEKTISK AKGQPREPQV YTLPPSRDEL TKNQVSLTCL VKGFYPSDIA VEWESNGQPE NNYKTTPPVL DSDGSFFLYS KLTVDKSRWQ QGNVFSCSVM HEALHNHYTQ KSLSLSPGKH HHHHH.
Q&A
What is TLR2 and what is its function in mice?
TLR2 (Toll-like receptor 2) is a pattern recognition receptor belonging to the Toll-like family of integral membrane proteins that serve as sentinels of the innate immune system. In mice, TLR2 is a 97 kDa, 760 amino acid glycoprotein containing a 563 amino acid extracellular region, 21 amino acid transmembrane segment, and a 176 amino acid cytoplasmic domain .
Unlike TLR4 which generally promotes inflammatory responses, TLR2 appears to have more nuanced roles. Research shows TLR2 provides a counter-signal to oppose deleterious effects of stress that may be related to depression . Additionally, TLR2 plays a critical role in radio-resistance, as TLR2 knockout mice show increased mortality and morbidity rates after radiation exposure compared to wild-type mice .
What is the structural composition of mouse TLR2?
Mouse TLR2 has distinct structural features essential for its function:
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Total length: 760 amino acids
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Extracellular region: 563 amino acids containing 16 leucine-rich repeats (LRRs)
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Transmembrane segment: 21 amino acids
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Cytoplasmic domain: 176 amino acids containing one 146 amino acid Toll/IL-1 receptor (TIR) domain
The leucine-rich repeats in the extracellular domain are crucial for pathogen recognition, while the TIR domain in the cytoplasmic tail is essential for downstream signaling events following ligand binding.
Where is TLR2 expressed in mouse tissues?
TLR2 is expressed across multiple cell types in mice, including:
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T cells (both αβ and γδ types)
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Monocytes
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Dendritic cells
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Neutrophils
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B cells
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Endothelial cells
Expression patterns can vary in response to different stimuli. For instance, hippocampal TLR2 mRNA levels were significantly reduced in mice displaying prolonged learned helplessness compared to non-stressed control mice . In respiratory research, TLR2 expression on both respiratory epithelia and immune cells has proven relevant for mucosal vaccination strategies against respiratory viruses like SARS-CoV-2 .
What mouse models are available for TLR2 research?
Several mouse models have been developed for TLR2 research:
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TLR2 knockout (TLR2−/−) mice: These mice lack functional TLR2 receptors and are used to study the role of TLR2 in various physiological and pathological processes .
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Conditional TLR2 knockout models: The Tlr2tm2(cre/ERT2)Dfil mouse strain contains a tamoxifen-inducible Cre recombinase, allowing for temporal control of TLR2 deletion .
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TLR2/TLR4 chimeric mice: These mice have TLR2 deficiency in either the hematopoietic or non-hematopoietic compartment, enabling researchers to determine the compartment-specific roles of TLR2 .
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Cell culture models: Mouse cell lines like Raw264.7 are frequently used to study TLR2 expression and function. These cells can be stimulated with agents like LPS and then analyzed using flow cytometry with fluorescein-conjugated anti-TLR2 antibodies .
What methods can be used to detect and quantify TLR2 expression in mouse tissues?
Multiple techniques are available for detecting and quantifying TLR2 expression:
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Flow cytometry: Fluorescein-conjugated anti-TLR2 antibodies (e.g., catalog # FAB1530F) can detect TLR2 expression on cell surfaces at single-cell resolution. This technique has been used successfully for detecting TLR2 in LPS-stimulated Raw264.7 cells .
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Quantitative PCR (qPCR): This method measures TLR2 mRNA levels in tissue samples and has been used to detect changes in TLR2 expression in the hippocampus of mice with prolonged learned helplessness .
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Immunohistochemistry: Enables visualization of TLR2 protein expression in tissue sections, providing spatial information about expression patterns.
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Western blotting: Quantifies TLR2 protein levels in tissue or cell lysates, allowing assessment of total TLR2 protein expression.
What methodological considerations are important when studying TLR2 in mouse models?
Several methodological considerations are critical when designing TLR2 studies:
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Strain selection: Different mouse strains may have varying baseline TLR2 expression levels. Background strain effects should be considered when using knockout models.
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Age and sex considerations: TLR2 expression and function may vary with age and sex. These variables should be controlled in experimental design.
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Specificity of reagents: Antibodies should be validated for specificity (e.g., using TLR2−/− controls). When using TLR2 agonists, potential off-target effects should be considered.
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Controls for behavioral studies: Pain sensitivity should be tested separately (e.g., hot plate test) to rule out confounding effects on behavioral tests like learned helplessness .
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Timing considerations: The duration of experiments is crucial, especially when studying recovery processes. TLR2's role in recovery from stress-induced behaviors requires extended observation periods (up to 9 weeks in some studies) .
How does TLR2 deficiency affect behavioral responses in mouse models of depression?
TLR2 deficiency has significant impacts on depression-like behaviors in mice, particularly in the learned helplessness model:
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Initial susceptibility: In standard learned helplessness protocols, TLR2−/− mice showed similar rates of learned helplessness induction as wild-type mice (90% vs. 80%) .
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Increased vulnerability: In modified protocols with reduced foot shock duration, 80% of TLR2−/− mice displayed learned helplessness compared to only 30% of wild-type mice, indicating increased susceptibility .
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Impaired recovery: Most significantly, TLR2−/− mice showed dramatically impaired recovery from learned helplessness. After 3 weeks, 70% of TLR2−/− mice still displayed learned helplessness versus only 20% of wild-type mice. This impaired recovery persisted through 9 weeks after induction .
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Molecular correlates: Wild-type mice that displayed prolonged learned helplessness had significantly lower hippocampal TLR2 mRNA levels compared to non-learned helpless or non-shocked mice .
These findings suggest TLR2 signaling plays a crucial role in resilience and recovery from stress-induced depressive-like behaviors.
How do TLR2 and TLR4 compare in their effects on stress responses in mice?
TLR2 and TLR4 show opposing roles in stress responses:
| Feature | TLR2 | TLR4 |
|---|---|---|
| Effect on learned helplessness | Opposes, promotes recovery | Promotes susceptibility |
| Knockout phenotype in standard protocol | 90% develop learned helplessness | Only 33% develop learned helplessness |
| Expression in prolonged learned helplessness | Decreased in hippocampus | Increased in hippocampus |
| Role in stress resilience | Protective | Detrimental |
While TLR4−/− mice are largely resistant to the induction of learned helplessness (only 33% display it vs. 80% of wild-type mice), TLR2−/− mice show impaired recovery from learned helplessness once it develops . This suggests that while TLR4 and TLR2 share some signaling components, they mediate distinct and sometimes opposing physiological responses to stress.
What role does TLR2 play in mucosal vaccination against respiratory viruses in mice?
TLR2 plays a critical role in mucosal vaccination against respiratory viruses like SARS-CoV-2:
These findings support the use of TLR2 agonists as adjuvants in mucosal vaccination strategies against respiratory viruses.
How do TLR2 agonists modulate immune responses in mice?
TLR2 agonists modulate immune responses in mice through several mechanisms:
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Radio-protection: Injection of the TLR2 agonist Pam3CSK4 into wild-type mice induces radio-resistance, protecting bone marrow cells from radiation damage .
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Mucosal immunity enhancement: The TLR2 agonist Pam2Cys used as an adjuvant in mucosal vaccination generates anti-Spike IgA antibodies, increases neutralizing antibody levels in both serum and airways, and enhances lung CD4+ T-cell responses .
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Non-specific protection: Mucosal administration of Pam2Cys alone provides short-term non-specific protection against SARS-CoV-2 in K18-hACE2 mice, suggesting activation of innate immune mechanisms .
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Compartment-specific effects: TLR2 agonists can activate both respiratory epithelial cells and immune cells, with TLR2 stimulation in either compartment facilitating early innate responses, while TLR2 stimulation of hematopoietic cells is essential for optimal antigen-specific responses .
How does TLR2 contribute to radio-resistance in mice?
TLR2 plays a critical role in protecting mice from radiation damage:
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Survival impact: TLR2 knockout (TLR2−/−) mice receiving 6.5 Gy radiation showed more severe mortality and morbidity rates compared to wild-type mice .
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Bone marrow protection: The cause of death in TLR2−/− mice appears to be severe and persistent bone marrow cell loss, suggesting TLR2 is important for protecting bone marrow cells from radiation damage .
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Therapeutic potential: Injection of the TLR2 agonist Pam3CSK4 into wild-type mice induced radio-resistance, suggesting potential applications in radiation protection .
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Signaling pathway: The radio-protective effect of TLR2 appears to involve the MyD88 pathway, as MyD88−/− mice were also more susceptible to radiation .
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Similarity to TLR4: TLR2's role in radio-resistance is similar to that of TLR4, suggesting common protective mechanisms among some Toll-like receptors .
These findings indicate that TLR2 signaling has important protective effects against radiation injury, particularly in preserving bone marrow cell function, which could have implications for radiotherapy and radiation exposure scenarios.
How does TLR2 signaling interact with other immune pathways in mice?
TLR2 signaling interacts with several other immune pathways:
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MyD88-dependent signaling: TLR2, like many other TLRs, signals through the adapter protein MyD88. MyD88−/− mice show increased susceptibility to radiation, similar to TLR2−/− mice .
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NF-κB pathway: TLR2 activation leads to NF-κB activation, similar to other TLRs. The NF-κB pathway is crucial for many protective effects of TLR signaling.
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Cross-talk with TLR4: TLR2 and TLR4 have opposing effects in stress responses. In prolonged learned helplessness, TLR2 expression decreases while TLR4 expression increases .
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Adaptive immunity: TLR2 activation during mucosal vaccination enhances both antibody responses (including IgA production) and T cell responses. TLR2 on hematopoietic cells is essential for optimal antigen-specific responses .
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Stress response systems: TLR2 provides a counter-signal to oppose deleterious effects of stress, suggesting interaction with neuroendocrine pathways involved in stress responses .
Understanding these interactions is crucial for developing targeted immunomodulatory therapies.
What are the contradictory findings in TLR2 mouse research and how can they be reconciled?
Several seemingly contradictory findings exist in TLR2 mouse research:
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Context-dependent roles in inflammation: In some contexts, TLR2 activation promotes pro-inflammatory responses, while in stress models, TLR2 appears to have anti-inflammatory/protective effects . This apparent contradiction may be reconciled by considering the specific cell types involved, the nature of the stimulus, and the presence of co-receptors.
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Initial vs. recovery effects in behavioral models: TLR2−/− mice show similar initial rates of learned helplessness as wild-type mice but demonstrate dramatically impaired recovery . This suggests TLR2 may be more important for resilience and recovery processes than for initial stress responses.
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Cell type-specific effects: TLR2 on both respiratory epithelia and immune cells facilitates early innate responses to mucosal vaccination, but TLR2 on hematopoietic cells is specifically required for optimal antigen-specific responses . This highlights the importance of cell type-specific functions of TLR2.
These complexities emphasize the need for careful experimental design and interpretation when studying TLR2 function in different physiological and pathological contexts.
Product Science Overview
Toll-like receptors (TLRs) are a family of pattern recognition receptors (PRRs) that play a crucial role in the innate immune system by recognizing pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs). Among these, Toll-like receptor 2 (TLR2) is particularly significant due to its ability to recognize a wide range of microbial components.
TLR2 was first identified as a receptor similar to the Drosophila Toll protein in 1998 . The TLR2 gene, located on chromosome 4, encodes the TLR2 protein, which is a type I transmembrane protein. The initial understanding of TLR2’s function came from studies showing its role in recognizing components of gram-positive bacteria .
TLR2 consists of three main domains:
TLR2 is expressed in various immune cells, including dendritic cells and macrophages. It recognizes a broad spectrum of microbial components, including lipoproteins, peptidoglycans, and lipoteichoic acids from gram-positive bacteria . Upon ligand binding, TLR2 forms heterodimers with either TLR1 or TLR6, which is essential for its function .
The activation of TLR2 triggers the myeloid differentiation primary-response protein 88 (MyD88)-dependent signaling pathway. This leads to the production of pro-inflammatory cytokines and type I interferons, which are crucial for initiating and regulating the immune response .
TLR2 has been implicated in various diseases, including infections, inflammatory conditions, and autoimmune disorders. For instance, TLR2 signaling is involved in the immune response to Clostridioides difficile infection . Overactivation of TLR2 can lead to chronic inflammation and tissue damage, making it a potential target for therapeutic interventions .
Recombinant TLR2 proteins, such as those derived from mice, are widely used in research to study the receptor’s function, signaling pathways, and role in disease. These recombinant proteins are produced using genetic engineering techniques and are essential tools for understanding TLR2’s mechanisms and developing new therapeutic strategies.
