Recombinant Viral B8R Biotinylated Protein, CF

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Recombinant Viral B8R Biotinylated Protein, CF Bioactivity
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Recombinant Viral B8R Biotinylated Protein, CF Summary

>95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
Endotoxin Level
<0.10 EU per 1 μg of the protein by the LAL method.
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. Th 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, biotinylated via sugars
Predicted Molecular Mass
30 kDa (unlabeled)

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.


Formulation Lyophilized from a 0.2 μm filtered solution in PBS.
Reconstitution Reconstitute at 250 μg/mL in PBS.
Shipping The product is shipped with polar packs. 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 Image

Bioactivity Bioactivity View Larger

Both Biotinylated Recombinant Viral B8R (Catalog # BT8225) and unlabeled Recombinant Viral B8R (Catalog # 8225-BR) 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. The similarity in activity highlights that the biotinylated protein is fully functional.

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.


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). IFN-gamma peptide mimetics that activate IFN-gamma R1 but 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.
Long Name
Soluble Interferon alpha/beta Receptor B8
Entrez Gene IDs
3707661 (Viral)
Alternate Names


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Primary Antibodies

His Tag Antibody

WB,Simple Western,Flow,AP,CyTOF-ready

Protein Purification Kits

Reconstitution Buffers

Staining Reagents


Supplemental Cell Selection Products

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