Catalog #BE0503

InVivoMAb anti-human TLR4 (CD284)

Clone HTA125
Reactivities Human
Applications in vitro blocking of TLR4 signaling
ex vivo blocking of TLR4 signaling
in vitro functional assay
Flow cytometry
Immunoprecipitation
Immunohistochemistry (frozen)
Immunohistochemistry (paraffin)
Immunofluorescence
Western blot
Isotype Mouse IgG2a, κ

$178.00 - $4,651.50

$178.00 - $4.00

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  • 100 mg - $4,651.50
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  • 1 mg - $178.00
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Product Description

The HTA125 monoclonal antibody reacts with human Toll-like receptor 4 (TLR4) through an epitope within the N-terminal region of its extracellular domain. TLR4 belongs to the evolutionarily conserved Toll-like receptor (TLR) family, which consists of 10 functional members in humans (TLR1-10). Human TLR4, also known as CD28, is primarily expressed in monocytes, macrophages, neutrophils, and dendritic cells (myeloid immune cells). TLR4 expression has also been reported in select non-myeloid immune cells, e.g., T cells and B cells, and nonimmune cell populations such as astrocytes, endothelial cells, epithelial cells and fibroblasts, in which its expression varies with cell differentiation and inflammatory state. Myeloid differentiation factor 2 (MD2) is essential for canonical lipopolysaccharide (LPS) recognition and TLR4 activation. Importantly, MD2 is not universally required for TLR4 cell-surface expression. Activated TLR4 recruits TIRAP and MyD88 at the plasma membrane, initiating signaling through downstream mediators, including TRAF6, to activate NF-κB and induce proinflammatory cytokines. After LPS stimulation, CD14-mediated TLR4 endocytosis promotes endosomal signaling through TRAM–TRIF/TICAM1 and the TBK1–IRF3 axis, resulting in type I interferon (IFN) production. TLR4 acts as a transmembrane pattern-recognition receptor that initiates innate immune responses, and depending upon the context, it is often studied in the pathophysiology of sepsis, endotoxic shock (from gram-negative bacterial infections), ischemia-reperfusion injury, atherosclerosis, hyperglycemia-related inflammation, osteoarthritis, cancer-associated inflammation in malignant tumors, and neuroinflammation, including processes implicated in Alzheimer’s disease. The HTA125 antibody has been reported to inhibit LPS-induced monocyte activation, highlighting its functional blocking efficacy and relevance to research on TLR4-mediated inflammatory responses.

Specifications

Isotype Mouse IgG2a, κ
Recommended Isotype Control(s) InVivoMAb mouse IgG2a isotype control, unknown specificity
Recommended Dilution Buffer InVivoPure pH 7.0 Dilution Buffer
Immunogen Ba/F3 cells expressing human TLR4
Reported Applications in vitro blocking of TLR4 signaling
ex vivo blocking of TLR4 signaling
in vitro functional assay
Flow cytometry
Immunoprecipitation
Immunohistochemistry (frozen)
Immunohistochemistry (paraffin)
Immunofluorescence
Western blot
Formulation PBS, pH 7.0
Contains no stabilizers or preservatives
Endotoxin ≤1EU/mg (≤0.001EU/μg)
Determined by LAL assay
Purity ≥95%
Determined by SDS-PAGE
Sterility 0.2 µm filtration
Production Purified from cell culture supernatant in an animal-free facility
Purification Protein G
Molecular Weight 150 kDa
Storage The antibody solution should be stored at the stock concentration at 4°C. Do not freeze.
Need a Custom Formulation? See All Antibody Customization Options

Application References

  • in vitro blocking of TLR4 signaling Flow Cytometry Immunofluorescence Immunoprecipitation
    Shimazu R, Akashi S, Ogata H, Nagai Y, Fukudome K, Miyake K, Kimoto M (1999). "MD-2, a molecule that confers lipopolysaccharide responsiveness on Toll-like receptor 4." J Exp Med 189(11):1777-82.

    Toll-like receptor 4 (TLR4) is a mammalian homologue of Drosophila Toll, a leucine-rich repeat molecule that can trigger innate responses against pathogens. The TLR4 gene has recently been shown to be mutated in C3H/HeJ and C57BL/10ScCr mice, both of which are low responders to lipopolysaccharide (LPS). TLR4 may be a long-sought receptor for LPS. However, transfection of TLR4 does not confer LPS responsiveness on a recipient cell line, suggesting a requirement for an additional molecule. Here, we report that a novel molecule, MD-2, is requisite for LPS signaling of TLR4. MD-2 is physically associated with TLR4 on the cell surface and confers responsiveness to LPS. MD-2 is thus a link between TLR4 and LPS signaling. Identification of this new receptor complex has potential implications for understanding host defense, as well as pathophysiologic, mechanisms.

  • in vitro blocking of TLR4 signaling Flow Cytometry Immunofluorescence Immunoprecipitation
    Shimazu R, Akashi S, Ogata H, Nagai Y, Fukudome K, Miyake K, Kimoto M (1999). "MD-2, a molecule that confers lipopolysaccharide responsiveness on Toll-like receptor 4." J Exp Med 189(11):1777-82.

    Toll-like receptor 4 (TLR4) is a mammalian homologue of Drosophila Toll, a leucine-rich repeat molecule that can trigger innate responses against pathogens. The TLR4 gene has recently been shown to be mutated in C3H/HeJ and C57BL/10ScCr mice, both of which are low responders to lipopolysaccharide (LPS). TLR4 may be a long-sought receptor for LPS. However, transfection of TLR4 does not confer LPS responsiveness on a recipient cell line, suggesting a requirement for an additional molecule. Here, we report that a novel molecule, MD-2, is requisite for LPS signaling of TLR4. MD-2 is physically associated with TLR4 on the cell surface and confers responsiveness to LPS. MD-2 is thus a link between TLR4 and LPS signaling. Identification of this new receptor complex has potential implications for understanding host defense, as well as pathophysiologic, mechanisms.

  • in vitro blocking of TLR4 signaling
    Kawai K, Shimura H, Minagawa M, Ito A, Tomiyama K, Ito M (2002). "Expression of functional Toll-like receptor 2 on human epidermal keratinocytes." J Dermatol Sci 30(3):185-94.

    Epidermal keratinocytes secrete cytokines, chemokines, and anti-microbial peptides in response to various microbial pathogens and their components including lipopolysaccharide (LPS). To identify the receptor(s) involved in the anti-microbial responses of epidermal keratinocytes, we analyzed expression of CD14, Toll-like receptor 2 (TLR2), and TLR4 on cultured normal human epidermal keratinocytes (NHEK). Although CD14 and TLR2 mRNA were expressed in cultured NHEK, only TLR2 was detected on the cell surface. Cultured NHEK did not express TLR4 mRNA or protein. Commercial LPS preparations could stimulate epidermal keratinocytes to produce beta-defensin-2 and IL-8, and the LPS response was inhibited with mAb specific for TLR2, but not for CD14 or TLR4. Repurified LPS and lipid A did not stimulate epidermal keratinocytes, whereas peptidoglycan (PGN) from Gram-positive bacteria and yeast cell wall particle induced beta-defensin-2 and IL-8 production. Thus, cultured NHEK express functional TLR2, but not CD14 or TLR4, and the "LPS" response of epidermal keratinocytes shown in the previous studies might be mediated by TLR2-dependent recognition of non-LPS bacterial components contaminating in commercial LPS preparations. In the normal human skin, however, epidermal keratinocytes expressed both TLR2 and TLR4. Because TLR4 was induced in epidermal keratinocytes by in vitro stimulation with PGN from Gram-positive bacteria, constitutive expression of TLR4 on epidermal keratinocytes in vivo might also be induced by continuous recognition of the resident skin flora containing Gram-positive bacteria through TLR2.

  • in vitro blocking of TLR4 signaling
    Kawai K, Shimura H, Minagawa M, Ito A, Tomiyama K, Ito M (2002). "Expression of functional Toll-like receptor 2 on human epidermal keratinocytes." J Dermatol Sci 30(3):185-94.

    Epidermal keratinocytes secrete cytokines, chemokines, and anti-microbial peptides in response to various microbial pathogens and their components including lipopolysaccharide (LPS). To identify the receptor(s) involved in the anti-microbial responses of epidermal keratinocytes, we analyzed expression of CD14, Toll-like receptor 2 (TLR2), and TLR4 on cultured normal human epidermal keratinocytes (NHEK). Although CD14 and TLR2 mRNA were expressed in cultured NHEK, only TLR2 was detected on the cell surface. Cultured NHEK did not express TLR4 mRNA or protein. Commercial LPS preparations could stimulate epidermal keratinocytes to produce beta-defensin-2 and IL-8, and the LPS response was inhibited with mAb specific for TLR2, but not for CD14 or TLR4. Repurified LPS and lipid A did not stimulate epidermal keratinocytes, whereas peptidoglycan (PGN) from Gram-positive bacteria and yeast cell wall particle induced beta-defensin-2 and IL-8 production. Thus, cultured NHEK express functional TLR2, but not CD14 or TLR4, and the "LPS" response of epidermal keratinocytes shown in the previous studies might be mediated by TLR2-dependent recognition of non-LPS bacterial components contaminating in commercial LPS preparations. In the normal human skin, however, epidermal keratinocytes expressed both TLR2 and TLR4. Because TLR4 was induced in epidermal keratinocytes by in vitro stimulation with PGN from Gram-positive bacteria, constitutive expression of TLR4 on epidermal keratinocytes in vivo might also be induced by continuous recognition of the resident skin flora containing Gram-positive bacteria through TLR2.

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