Recombinant Viral B8R Protein

Potent inhibitor of IFN-gamma
Formulations:
Catalog # Availability Size / Price Qty
8225-BR-025
B8R Inhibits IFN-gamma Activity.
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Recombinant Viral B8R Protein Summary

Purity
>95%, by SDS-PAGE with silver staining.
Endotoxin Level
<0.10 EU per 1 μg of the protein by the LAL method.
Activity
Measured by its ability to inhibit rhIFN-gamma mediated protection of HeLa human cervical epithelial carcinoma cells to viral lysis. Meager, A. (1987) in Lymphokines and Interferons, a Practical Approach. Clemens, M.J. et al. (eds): IRL Press. 129. The ED50 for this effect is 0.5-3 ng/mL.
Source
Chinese Hamster Ovary cell line, CHO-derived viral B8R protein
Lys18-Ser272, with a C-terminal 6-His tag
Accession #
N-terminal Sequence
Analysis
Lys18
Structure / Form
Noncovalently-linked homodimer
Predicted Molecular Mass
30 kDa (monomer)
SDS-PAGE
37-43 kDa, reducing conditions

Product Datasheets

Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.

8225-BR

Formulation Lyophilized from a 0.2 μm filtered solution in PBS with BSA as a carrier protein.
Reconstitution Reconstitute at 500 μg/mL in sterile PBS.
Shipping The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 12 months from date of receipt, -20 to -70 °C as supplied.
  • 1 month, 2 to 8 °C under sterile conditions after reconstitution.
  • 3 months, -20 to -70 °C under sterile conditions after reconstitution.

8225-BR/CF

Formulation Lyophilized from a 0.2 μm filtered solution in PBS.
Reconstitution Reconstitute at 500 μg/mL in sterile PBS.
Shipping The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 12 months from date of receipt, -20 to -70 °C as supplied.
  • 1 month, 2 to 8 °C under sterile conditions after reconstitution.
  • 3 months, -20 to -70 °C under sterile conditions after reconstitution.

Data Images

Bioactivity B8R Inhibits IFN-gamma Activity. View Larger

The viral receptor B8R inhibits IFN-gamma-mediated protection of HeLa human cervical epithelial carcinoma cells to viral lysis. The ED50for this effect is 0.5-3 ng/mL.

SDS-PAGE View Larger

1 μg/lane of Recombinant Viral B8R (Catalog # 8225-BR) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by silver staining, showing R bands at 37-43 kDa and NR bands at 67-92 kDa.

Reconstitution Calculator

Reconstitution Calculator

The reconstitution calculator allows you to quickly calculate the volume of a reagent to reconstitute your vial. Simply enter the mass of reagent and the target concentration and the calculator will determine the rest.

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Background: B8R

B8R is a secreted Interferon gamma (IFN-gamma ) binding protein encoded by the open reading frame of the Vaccina virus (smallpox) (1, 2). B8R is a 43 kDa protein and shares only 19% amino acid sequence identity with the extracellular region of the human IFN-gamma Receptor 1 (IFN-gamma R1). However, B8R binds IFN-gamma orthologs from multiple species including human, rat, rabbit, bovine, and chicken with high affinity, but it binds mouse IFN-gamma with low affinity (1, 3, 4). During infection, virally‑induced B8R binds and sequesters endogenous IFN-gamma, thereby suppressing the host immune response and promoting viral immune evasion (5). While B8R is not required for viral replication, it contributes significantly to Vaccinia virus virulence and is frequently inactivated prior to Vaccinia use in vaccines (5-9). Peptide IFN-gamma mimetics that activate IFN-gamma R1 and are not bound and sequestered by B8R have been developed for research and therapeutic use (10, 11).

References
  1. Alcami, A. and G.L. Smith (1995) J. Virol. 69:4633.
  2. Goebel, S.J. et al. (1990) Virology 179:247.
  3. Puehler, F. et al. (1998) Virology 248:231.
  4. Mossman, K. et al. (1995) Virology 208:762.
  5. Smith, G.L. et al. (2013) J. Gen. Virol. 94:2367.
  6. Symons, J.A. et al. (2002) J. Gen. Virol. 83:1953.
  7. Verardi, P.H. et al. (2001) J. Virol. 75:11.
  8. Denes, B. et al. (2006) J. Gene Med. 8:814.
  9. Dimier, J. et al. (2011) J. Virol. 85:5016.
  10. Ahmed, C.M. et al. (2007) J. Immunol. 178:4576.
  11. Ahmed, C.M. et al. (2005) J. Virol. 79:5632.
  12.  
Long Name
Soluble Interferon alpha/beta Receptor B8
Entrez Gene IDs
3707661 (Viral)
Alternate Names
B8R

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