B18R recombinant protein - IFN-α/β inhibitor

InvitroFit™ - Carrier-free - Cell-culture tested

InvivoGen offers recombinant B18R, a potent inhibitor of type I interferon (IFN) signaling. Due to its neutralizing feature, it is highly used to study host innate pattern recognition receptor (PRR) and subsequent anti-viral T cell responses upon viral infection [1-2]. B18R is also known to increase cell viability and mRNA transfection efficacy, especially during pluripotent stem cell (iPSC) reprogramming. It is able to maintain RNA-replicons and increase the viability of cells upon transfection with synthetic mRNA [3].

InvivoGen's recombinant B18R protein is produced in Chinese hamster ovary (CHO) cells, which ensures protein glycosylation and bona fide 3D structure. Of note, glycosylation stabilizes proteins against physicochemical instabilities.

It successfully blocks type I IFN-mediated signaling, as verified in HEK-Blue™ IFN-α/β cells stimulated with recombinant human IFN-α. Also, B18R increases RNA-transfection efficacy, as verified by transfecting THP1-Dual™ cells with GFP mRNA ± B18R (see figures).

Description

B18R, also called the soluble IFN-α/β receptor B18, is naturally encoded by the western reverse (WR) strain of the vaccinia virus. It acts as a decoy receptor with specificity for mouse, human, rabbit, pig, rat, and cow type I interferons (IFNs) which represent the first line of host defenses against viral infection [4.5]. Thus, B18R effectively prevents the establishment of the antiviral state and enables virus replication and pathogenicity in virus-infected cells [6-7].

Key features:

• Potent inhibitor of type I interferons (e.g. IFN-α, IFN-β, IFN-κ,...)
• Recombinant protein produced in CHO cells
• Hexahistidine (His6) tag
• Provided carrier-free
• InvitroFit™ grade: each lot is highly pure (≥95%) and functionally tested

References:

1. Manel N, et al., 2010. A cryptic sensor for HIV-1 activates antiviral innate immunity in dendritic cells. Nature.;467(7312):214-7. 
2. Waibler Z, et al., 2009. Vaccinia virus-mediated inhibition of type I interferon responses is a multifactorial process involving the soluble type I interferon receptor B18 and intracellular components. J Virol.;83(4):1563-71.
3. Warren L, et al., 2010. Highly efficient reprogramming to pluripotency and directed differentiation of human cells with synthetic modified mRNA. Cell Stem Cell.; 7(5):618-30.
4.Symons JA, et al., 1995. Vaccinia virus encodes a soluble type I interferon receptor of novel structure and broad species specificity. Cell.;81(4):551-60.
5. Colamonici OR, et al., 1995. Vaccinia virus B18R gene encodes a type I interferon-binding protein that blocks interferon alpha transmembrane signaling. J Biol Chem. ;270(27):15974-8.
6. Kim YG, et al., 2017. Recombinant Vaccinia virus-coded interferon inhibitor B18R: Expression, refolding and a use in a mammalian expression system with a RNA-vector. PLoS One. ;12(12):e0189308.
7. Alcamí A, Symons JA, Smith GL, 2000. The vaccinia virus soluble alpha/beta interferon (IFN) receptor binds to the cell surface and protects cells from the antiviral effects of IFN. J Virol.;74(23):11230-9.