Recombinant Viral B8R Protein


The viral receptor B8R inhibits IFN-gamma-mediated protection of HeLa human cervical epithelial carcinoma cells to viral lysis. The ED50 for this effect is 0.5-3 ng/mL.
1 μg/laneof Recombinant Viral B8R (Catalog # 8225-BR) was resolved with SDS-PAGE underreducing (R) and non-reducing (NR) conditions and visualized by silverstaining, showing R bands at 37-43 kDa and NR bands at 67-92 more

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Recombinant Viral B8R Protein Summary

Additional Information
Potent inhibitor of IFN-gamma
Details of Functionality
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.
Chinese Hamster Ovary cell line, CHO-derived viral B8R protein
Lys18-Ser272, with a C-terminal 6-His tag
Accession #
N-terminal Sequence
Structure / Form
Noncovalently-linked homodimer
Protein/Peptide Type
Recombinant Proteins
>95%, by SDS-PAGE with silver staining.
Endotoxin Note
<0.10 EU per 1 μg of the protein by the LAL method.


  • Bioactivity
Theoretical MW
30 kDa (monomer).
Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.
37-43 kDa, reducing conditions

Packaging, Storage & Formulations

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.
Lyophilized from a 0.2 μm filtered solution in PBS with BSA as a carrier protein.
>95%, by SDS-PAGE with silver staining.
Reconstitution Instructions
Reconstitute at 500 μg/mL in sterile PBS.


This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Alternate Names for Recombinant Viral B8R Protein

  • 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).
  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.

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Array 8225-BR

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Gene Symbol B8R