NEUTRALIZATION-RESISTANT VARIANTS OF A NEUROTROPIC CORONAVIRUS ARE GENERATED BY DELETIONS WITHIN THE AMINO-TERMINAL HALF OF THE SPIKE GLYCOPROTEIN
NEUTRALIZATION-RESISTANT VARIANTS OF A NEUROTROPIC CORONAVIRUS ARE GENERATED BY DELETIONS WITHIN THE AMINO-TERMINAL HALF OF THE SPIKE GLYCOPROTEIN
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DOI：
10.1128/jvi.64.2.731-741.1990
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发表时间：
1990-02-01
影响因子：
5.4
通讯作者：
BUCHMEIER, MJ
中科院分区：
文献类型：
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作者：
GALLAGHER, TM;PARKER, SE;BUCHMEIER, MJ
小鼠肝炎病毒4型（MHV-4）的神经减毒变异体被选择用于抵抗中和单克隆抗体（R。G. Daldman，P. W. Lampert，P. J.塔尔博特和M. J. Buchmeier，J. Virol. 59：463-471，1986）被发现在mRNA 3及其蛋白产物180千道尔顿病毒粒子刺突（S）糖蛋白中具有大的缺失。通过使用针对所选部分的链的抗肽抗体，缺失被映射到氨基末端S1片段的中间，S的两个翻译后裂解产物之一，并涉及省略15千道尔顿的蛋白质。只有在病毒通过培养细胞系多次传代后才能选择缺失突变体;最低传代的MHV-4贮备液含有可通过中和单克隆抗体选择的推定点突变体，但无缺失。在用于病毒繁殖的四种细胞系中观察到缺失突变体相对于野生型病毒的生长增强，这归因于延迟和减少的细胞病变效应，使培养物能够支持病毒生产延长时间。这一假设得到加强的发现，没有选择性优势的缺失突变体中观察到的两个细胞系耐病毒诱导的细胞病变的影响。这些结果表明，MHV-4在培养物中的传代产生S结构的异质性，并最终选择具有降低的毒力特性的罕见的耐中和缺失突变体。
Neuroattenuated variants of mouse hepatitis virus type 4 (MHV-4) selected for resistance to neutralizing monoclonal antibodies (R. G. Dalziel, P. W. Lampert, P. J. Talbot, and M. J. Buchmeier, J. Virol. 59:463-471, 1986) were found to harbor large deletions in both mRNA 3 and its protein product, the 180-kilodalton virion spike (S) glycoprotein. By using antipeptide antibodies directed against selected portions of the chain, deletions were mapped to the middle of the amino-terminal S1 fragment, one of the two posttranslational cleavage products of S, and involved omission of 15 kilodaltons of protein. Deletion mutants could be selected only after multiple passage of virus through cultured cell lines; minimally passaged MHV-4 stocks contained putative point mutants selectable by neutralizing monoclonal antibodies but no deletions. Enhanced growth of deletion mutants relative to wild-type virus was observed in four cell lines used for virus propagation and was attributed to delayed and diminished cytopathic effects that allowed cultures to support virus production for prolonged periods. This hypothesis was reinforced by the finding that no selective advantage for the deletion mutants was observed in two cell lines resistant to virus-induced cytopathic effects. These results indicate that the passaging of MHV-4 in culture generates heterogeneity in S structure and eventually selects for rare neutralization-resistant deletion mutants with decreased virulence properties.