Colamonici O R, Domanski P, Sweitzer S M, Larner A, Buller R M
Department of Pathology, University of Tennessee, Memphis 38163, USA.
J Biol Chem. 1995 Jul 7;270(27):15974-8. doi: 10.1074/jbc.270.27.15974.
Poxviruses encode a large number of proteins that attenuate the inflammatory and immune responses to infection. In this report we demonstrate that a number of orthopoxviruses express a type I interferon (IFN)-binding protein, which is encoded by the B18R open reading frame in the WR strain of vaccinia virus. The B18R protein has significant regions of homology with the alpha subunits of the mouse, human, and bovine type I IFN receptors, bound human IFN alpha 2 with high affinity, and inhibited transmembrane signaling as demonstrated by inhibition of Fc receptor factor gamma 1/gamma 2 and interferon-stimulated gene factor-3 formation as well as inhibition of the IFN alpha antiviral response. Among viral host response modifiers, the B18R protein is unique inasmuch as it exists as a soluble extracellular as well as a cell surface protein and thus should effectively block both autocrine and paracrine functions of IFN.
痘病毒编码大量可减弱对感染的炎症和免疫反应的蛋白质。在本报告中，我们证明多种正痘病毒表达一种I型干扰素（IFN）结合蛋白，该蛋白由痘苗病毒WR株中的B18R开放阅读框编码。B18R蛋白与小鼠、人类和牛I型IFN受体的α亚基具有显著的同源区域，能以高亲和力结合人IFNα2，并抑制跨膜信号传导，这可通过抑制Fc受体因子γ1/γ2和干扰素刺激基因因子-3的形成以及抑制IFNα抗病毒反应来证明。在病毒宿主反应调节因子中，B18R蛋白是独特的，因为它以可溶性细胞外蛋白以及细胞表面蛋白的形式存在，因此应能有效阻断IFN的自分泌和旁分泌功能。
