Also known as: Vaccinia Virus-Encoded Neutralizing Type I Interferon Receptor; Type I IFN inhibitor
RUO: For Research Use Only
Contents: B18R Recombinant Protein Carrier-Free Catalog Number: 34-8185 Formulation: Sterile liquid; phosphate buffered saline, pH 7.2, 150 mM NaCl, with no carriers or preservatives. 0.22 uM filtered. Storage Conditions: Store at less than or equal to -70°C. Handling Conditions: For best recovery, quick-spin vial prior to opening. Use in sterile envrioment. Source: Insect cells infected with baculovirus: amino acids 22-353 of Vaccinia Virus B18R (accession # D01019). Molecular Mass: The polypeptide has a predicted molecular mass of 38,389. The DTT-reduced protein migrates as a 48 kDa polypeptide on SDS-PAGE due to glycosylation. The non-reduced protein migrates as a 46 kDa polypeptide on SDS-PAGE due to internal cystines. Purity: Greater than 98%, as determined by SDS-PAGE. Endotoxin Level: Less than 0.05 ng/ug cytokine as determined by the LAL assay. Bioactivity: Measured by neutralization of exogenous or CpG-induced endogenous IFN-alpha or beta effects in an assay of IL-12 p40 production from CD40L-activated monocytes.
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34-8185-85
500 ug
Note: Several countries will continue to be supplied via distributors. Country specific prices may apply.
Flow Cytometry Product Notes: Test Sizes: To accommodate multicolor flow cytometry, eBioscience is in the process of reducing test size volumes from 20 µl to 5 µl. Please check your antibody vial for the recommended test size. Fluorochrome Replacements: eBioscience is in the process of replacing all Alexa Fluor® 647 conjugated products with eFluor® 660 conjugated products.
Description
The B18R protein is a vaccinia virus-encoded receptor with specificity for mouse, human, rabbit, pig, rat, and cow type I interferons which has potent neutralizing activity. The B18R protein is a type I interferon receptor encoded by the B18R gene of the Western Reserve vaccinia virus strain. The 60-65 kD glycoprotein is related to the interleukin-1 receptors and is a member of the immunoglobulin superfamily, unlike other type I IFN-receptors, which belong to the class II cytokine receptor family. The B18R protein has a high affinity (KD, 174 pM) for human IFN alpha and, unlike other type I IFN receptors, has broad species specificity, binding to type I interferons of human, mouse, rat, rabbit, pig, and cow. Among viral host response modifiers, the B18R protein is unique in that it exists as a soluble extracellular, as well as a cell surface protein, enabling blockage of both autocrine and paracrine IFN functions. The B18R protein has been shown to inhibit the antiviral potency of IFN-alpha1, IFN-alpha2 , IFN-alpha-8/1/8, and IFN-omega on human cells. The soluble B18R protein is highly potent for neutralizing type I interferons, which include IFN-alpha, beta, delta, kappa.
Applications Reported
For research use only, not for diagnostic or therapeutic use. Recombinant B18R is fully biologically active.
Applications Tested
This recombinant B18R protein (type I IFN receptor) has been tested in bioassay for neutralization of mouse and human interferons (α and β). Human IFN: Pre-incubation of recombinant human IFN-α2a with 0.1 μg/ml B18R for 1 hr at RT was found to neutralize completely the activity of 1 ng/ml IFN-α2a. Mouse IFN: In an assay of EMCV infection of L929 cells, pre-incubation of recombinant mouse IFN-αA with 250.0 picograms/ml B18R for 1 hr at RT was found to neutralize completely the activity of 5 pg/ml (1 Unit) mIFN-αA; the ND50 for this effect of B18R on 5 pg/ml (1 Unit) mouse IFN-αA was 30 pg/ml B18R.
References
Symons, J., et al. 1995. Vaccinia virus encodes a soluble type I interferon receptor of novel structure and broad species specificity. Cell. 81: 551-560.
Colamonici, O., et al. 1995. Vaccinia virus B18R gene encodes a type I interferon-binding protein that blocks interferon alpha transmembrane signaling. J. Biol. Chem. 270: 15974 – 15978.
Vancova, I., et al. 1998. Vaccinia virus protein B18R inhibits the activity and cellular binding of the novel type interferon-delta. J. General Virol. 79: 1647-169.
Nagai, T., et al. 2003. Timing of IFN-beta exposure during human dendritic cell maturation and naive Th cell stimulation has contrasting effects on Th1 subset generation: a role for IFN-beta-mediated regulation of IL-12 family cytokines and IL-18 in naive Th cell differentiation. J. Immunol. 171: 5233-43. [Bioassay] Meyers JA, et al. 2006. Blockade of TLR9 agonist-induced type I interferons promotes inflammatory cytokine IFN-gamma and IL-17 secretion by activated human PBMC. Cytokine. 35: 235-46. (B18R, BA PubMed)
