Measured by its ability to inhibit Type-I IFN-mediated anti-viral activity. Symons, J.A. et al. (1995) Cell 81:551. The ED50 for this effect, as measured by inhibition of Recombinant Human IFN‑ alpha 2 (Catalog # 11105-1)
, is 0.3-1.8 ng/mL.
Source
Human embryonic kidney cell, HEK293-derived viral B18R protein
>90%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
Endotoxin Note
<0.10 EU per 1 μg of the protein by the LAL method.
Applications/Dilutions
Dilutions
Bioactivity
Theoretical MW
65 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.
SDS-PAGE
80-95 kDa, reducing conditions
Publications
Read Publications using 8185-BR in the following applications:
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70 °C as supplied.
Buffer
Lyophilized from a 0.2 μm filtered solution in PBS.
Purity
>90%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
Reconstitution Instructions
Reconstitute at 500 μg/mL in PBS.
Notes
This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.
Alternate Names for Recombinant Viral B18R Protein, CF
B18R
Background
B18R
(Soluble IFN alpha/beta receptor B18) is a 60-65 kDa protein
encoded by the Vaccinia virus genome and by the genomes of other
orthopoxviruses. Its function represents one of several mechanisms used
by these viruses to evade the host immune response (1, 2). It is known
as B18R in the Western Reserve (WR) strain of Vaccinia but as B19R in
the Copenhagen strain (3). There is a structurally-unrelated, larger
Vaccinia protein that is also known as B18R (or B16R) that contains
multiple ankyrin-like repeats (4). The soluble IFN receptor B18R,
however, contains three immunoglobulin-like domains and shows homology
to human, mouse, and bovine type I IFN receptors (5). The Wyeth
strain of Vaccinia virus encodes a truncated protein that lacks the
C-terminal Ig-like domain, and B18R is functionally absent in the Lister
strain (6, 7). B18R functions as a decoy receptor for type I
IFNs (IFN alpha, beta, omega). It binds to type I IFNs from multiple species and prevents IFN signaling through its receptors
(6-8). B18R binds to the surface of virus infected and uninfected cells
where it retains its capacity to bind and neutralize IFN (6, 8). It
shields those cells from the antiviral effects of type I IFNs,
thereby enabling virus replication and pathogenicity (6-8). B18R also
limits the effectiveness of IFN alpha produced following TLR activation
(9), and it limits adaptive T cell responses (3). The B18R viral protein also acts to protect cells during mRNA transfection to produce induced pluripotent stem cells (iPSCs) from somatic cells (10). The addition of B18R results in increased cell viability of iPSCs in the presence of modified synthetic mRNAs such as OCT4, SOX2, KLF4, MYC, NANOG, and LIN28A. Using mRNAs in combination with B18R allows for integration-free reprogramming of somatic cells to iPSCs without the use of viral vectors or genomic modification.
Smith, G.L. et al. (2013) J. Gen. Virol. 94:2367.
Perdiguero, B. and M. Esteban (2009) J. Interferon Cytokine Res. 29:581.
Gomez, C.E. et al. (2012) J. Virol. 86:5026.
Goebel, S.J. et al. (1990) Virology 179:247.
Smith, G.L. and Y.S. Chan (1991) J. Gen. Virol. 72:511.
Alcami, A. et al. (2000) J. Virol. 74:11230.
Symons, J.A. et al. (1995) Cell 81:551.
Colamonici, O.R. et al. (1995) J. Biol. Chem. 270:15974.
Waibler, Z. et al. (2009) J. Virol. 83:1563.
Warren, L. et al. (2010) Cell Stem Cell. 7:618.
Publications for B18R (8185-BR)(5)
We have publications tested in 2 confirmed species: Human, Mouse.
We have publications tested in 2 applications: Bioassay, Neutralization.
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