Lalani A S, Ness T L, Singh R, Harrison J K, Seet B T, Kelvin D J, McFadden G, Moyer R W
Department of Biochemistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada.
Virology. 1998 Oct 10;250(1):173-84. doi: 10.1006/viro.1998.9340.
Many poxviruses express a 35-40-kDa secreted protein, termed "T1" (for leporipoxviruses) or "35kDa" (for orthopoxviruses), that binds CC-chemokines with high affinity but is unrelated to any known cellular proteins. Many previously identified poxvirus cytokine-binding proteins display strict species ligand-binding specificity. Because the T1 and 35kDa proteins share only 40% amino acid identity, we compared the abilities of purified myxoma virus-T1 (M-T1) and vaccinia virus (strain Lister)- and rabbitpox virus-35kDa proteins to inhibit human CC-chemokines in vitro. All three proteins were equally effective in preventing several human CC-chemokines from binding to target chemokine receptors and blocking subsequent intracellular calcium release. The inhibitory affinities were comparable (Ki = 0.07-1.02 nM). These proteins also displayed similar abilities to inhibit (IC50 = 6.3-10.5 nM) human macrophage inflammatory protein-1alpha-mediated chemotaxis of human monocytes. None of the viral proteins blocked interleukin-8-mediated calcium flux or chemotaxis of human neutrophils, confirming that the biological specificity of the T1/35kDa family is targeted inhibition of CC-chemokines. Despite the significant sequence divergence between the leporipoxvirus T1 and orthopoxvirus 35kDa proteins, our data suggest that their CC-chemokine binding and inhibitory properties appear to be species nonspecific and that the critical motifs most likely reside within the limited regions of conservation.
许多痘病毒表达一种35 - 40千道尔顿的分泌蛋白，称为“T1”（针对兔痘病毒）或“35kDa”（针对正痘病毒），它能与CC趋化因子高亲和力结合，但与任何已知细胞蛋白无关。许多先前鉴定的痘病毒细胞因子结合蛋白表现出严格的物种配体结合特异性。由于T1和35kDa蛋白仅共享40%的氨基酸同一性，我们比较了纯化的黏液瘤病毒 - T1（M - T1）、痘苗病毒（李斯特株）和兔痘病毒 - 35kDa蛋白在体外抑制人CC趋化因子的能力。这三种蛋白在阻止几种人CC趋化因子与靶趋化因子受体结合并阻断随后的细胞内钙释放方面同样有效。抑制亲和力相当（Ki = 0.07 - 1.02 nM）。这些蛋白在抑制（IC50 = 6.3 - 10.5 nM）人巨噬细胞炎性蛋白 - 1α介导的人单核细胞趋化方面也表现出相似的能力。没有一种病毒蛋白能阻断白细胞介素 - 8介导的人中性粒细胞钙通量或趋化，这证实了T1/35kDa家族的生物学特异性是靶向抑制CC趋化因子。尽管兔痘病毒T1和正痘病毒35kDa蛋白之间存在显著的序列差异，但我们的数据表明它们的CC趋化因子结合和抑制特性似乎是非物种特异性的，并且关键基序很可能位于有限的保守区域内。
