PB2 amino acid at position 627 affects, replicative efficiency, but not cell tropism, of Hong Kong H5N1 influenza A viruses in mice
PB2 amino acid at position 627 affects, replicative efficiency, but not cell tropism, of Hong Kong H5N1 influenza A viruses in mice
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DOI：
10.1016/j.virol.2003.11.030
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发表时间：
2004-03-15
期刊：
影响因子：
3.7
通讯作者：
Kawaoka, Y
中科院分区：
文献类型：
--
作者：
Shinya, K;Hamm, S;Kawaoka, Y
PB2蛋白627位的谷氨酸替换为赖氨酸，可将从人体内分离的非致死性H5N1甲型流感病毒转化为小鼠中的致死性病毒。与仅在呼吸器官中复制的非致死性病毒不同，致死性分离病毒在多种器官中复制，产生全身性感染。尽管两种病毒在毒力和器官趋向性上有明显差异，但尚不清楚这种差异是由于细胞趋向性的差异还是由于非致死性病毒在小鼠细胞中的复制能力降低。为了确定这种单一氨基酸变化如何影响小鼠的毒力和器官亲和性，我们研究了两种H5N1病毒在体内和体外的生长动力学。627位PB2氨基酸的特性对鸡胚成纤维细胞和鹌鹑细胞系的病毒复制效率没有明显影响；然而，在这个位置上有赖氨酸而不是谷氨酸的病毒在不同的小鼠细胞中生长得更好。当在小鼠中研究这种替代的效果时，所有的试验病毒都显示出相同的细胞趋向性，但在627位含有赖氨酸的病毒感染的传播速度比在该位置含有谷氨酸的病毒更快。进一步的分析显示了局部免疫反应的差异：在627位含有赖氨酸的病毒感染肺部的中性粒细胞浸润比缺乏谷氨酸取代的病毒持续的时间更长。我们的数据表明，PB2蛋白627位的氨基酸决定了病毒在小鼠（非禽类）细胞中的复制效率，而不是在小鼠不同器官的细胞间的趋向性。赖氨酸的存在导致更具攻击性的病毒复制，压倒宿主的防御机制，导致小鼠的高死亡率。(C) 2004爱思唯尔公司版权所有。
A single amino acid substitution, from glutamic acid to lysine at position 627 of the PB2 protein, converts a nonlethal H5N1 influenza A virus isolated from a human to a lethal virus in mice. In contrast to the nonlethal virus, which replicates only in respiratory organs, the lethal isolate replicates in a variety of organs, producing systemic infection. Despite a clear difference in virulence and organ tropism between the two viruses, it remains unknown whether the dissimilarity is a result of differences in cell tropism or the reduced replicative ability of the nonlethal virus in mouse cells in general. To determine how this single amino acid change affects virulence and organ tropism in mice, we investigated the growth kinetics of the two H5N1 viruses both in vitro and in vivo. The identity of the PB2 amino acid at position 627 did not appreciably affect viral replicative efficiency in chicken embryo fibroblasts and a quail cell line; however, viruses with lysine at this position instead of glutamic acid grew better in the different mouse cells tested. When the effect of this substitution was investigated in mice, all of the test viruses showed the same cell tropism, but infection by viruses containing lysine at position 627 spread more rapidly than those viruses containing glutamic acid at this position. Further analysis showed a difference in local immune responses: neutrophil infiltration in lungs infected with viruses containing lysine at position 627 persisted longer than that associated with viruses lacking a glutamic acid substitution. Our data indicate that the amino acid at position 627 of the PB2 protein determines the efficiency of viral replication in mouse (not avian) cells, but not tropism among cells in different mouse organs. The presence of lysine leads to more aggressive viral replication, overwhelming the host's defense mechanisms and resulting in high mortality rates in mice. (C) 2004 Elsevier Inc. All rights reserved.