Recombinant Viral B8R Protein

R&D Systems, part of Bio-Techne | Catalog # 8225-BR

Potent inhibitor of IFN-gamma
R&D Systems, part of Bio-Techne
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Carrier Free
8225-BR-025/CF
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With Carrier
8225-BR-025
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Key Product Details

Source

CHO

Accession #

P24770

Structure / Form

Noncovalently-linked homodimer

Conjugate

Unconjugated

Applications

Bioactivity

View all B8R Proteins and Enzymes »

Product Specifications

Source

Chinese Hamster Ovary cell line, CHO-derived viral B8R protein
Lys18-Ser272, with a C-terminal 6-His tag

Purity

>95%, by SDS-PAGE with silver staining.

Endotoxin Level

<0.10 EU per 1 μg of the protein by the LAL method.

N-terminal Sequence Analysis

Lys18

Predicted Molecular Mass

30 kDa (monomer)

SDS-PAGE

37-43 kDa, reducing conditions

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.

Scientific Data Images for Recombinant Viral B8R Protein

B8R Inhibits IFN-gamma Activity.

B8R Inhibits IFN-gamma Activity.

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.
B8R Inhibits IFN-gamma Activity.

B8R Inhibits IFN-gamma Activity.

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.

Formulation, Preparation and Storage

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.

Carrier: 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.
Carrier Free: 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.

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)

Gene Symbol

B8R

UniProt

P24770

Additional B8R Products

Product Documents for Recombinant Viral B8R Protein

Product Datasheets

Certificate of Analysis

To download a Certificate of Analysis, please enter a lot number in the search box below.

Note: Certificate of Analysis not available for kit components.

Download SDS 8225-BR (with carrier)
Download SDS 8225-BR/CF (carrier free)

Product Specific Notices for Recombinant Viral B8R Protein

For research use only

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