Alcamí A, Smith G L
Sir William Dunn School of Pathology, University of Oxford, U.K.
Comp Immunol Microbiol Infect Dis. 1996 Sep;19(4):305-17. doi: 10.1016/0147-9571(96)00013-6.
Poxviruses encode a broad range of proteins that counteract the formidable attack of the immune response initiated in the host after infection, among which are proteins that mimic the extracellular binding domain of host cytokine receptors and are secreted from virus-infected cells. A soluble interferon-gamma receptor (IFN-gamma R) is produced early after infection and efficiently blocks the binding of IFN-gamma to cellular receptors, thus inhibiting both the anti-viral and immune functions of IFN-gamma. An IFN-gamma R is highly conserved among members of the poxvirus family, suggesting a major role in viral pathogenesis. The highly species-specific nature of the IFN system enables questions concerning the evolutionary relationship between poxviruses and their hosts to be addressed. The IFN-gamma R encoded by myxoma virus, a natural pathogen of rabbits, is specific for rabbit IFN-gamma. However, the IFN-gamma R encoded by orthopoxviruses (vaccinia, cowpox, camelpox, ectromelia) shows a novel, broad species specificity suggesting that these viruses have evolved in several species. The implications for the unknown origin and natural host(s) of vaccinia virus are discussed.
痘病毒编码多种蛋白质，以对抗感染后宿主启动的免疫反应的强大攻击，其中包括模拟宿主细胞因子受体细胞外结合域并从病毒感染细胞中分泌的蛋白质。可溶性干扰素-γ受体（IFN-γR）在感染后早期产生，并有效阻断IFN-γ与细胞受体的结合，从而抑制IFN-γ的抗病毒和免疫功能。IFN-γR在痘病毒家族成员中高度保守，表明其在病毒发病机制中起主要作用。IFN系统的高度物种特异性使得有关痘病毒与其宿主之间进化关系的问题得以解决。兔黏液瘤病毒（一种兔的天然病原体）编码的IFN-γR对兔IFN-γ具有特异性。然而，正痘病毒（痘苗病毒、牛痘病毒、骆驼痘病毒、鼠痘病毒）编码的IFN-γR表现出一种新的、广泛的物种特异性，表明这些病毒在多个物种中进化。本文讨论了痘苗病毒未知起源和天然宿主的相关问题。
