Epistastic Interactions within the Junín Virus Envelope Glycoprotein Complex Provide an Evolutionary Barrier to Reversion in the Live-Attenuated Candid#1 Vaccine.
Epistastic Interactions within the Junín Virus Envelope Glycoprotein Complex Provide an Evolutionary Barrier to Reversion in the Live-Attenuated Candid#1 Vaccine.
复制标题
胡南病毒包膜糖蛋白复合物内的表观相互作用为减毒活病毒的逆转提供了进化障碍
DOI：
10.1128/jvi.01682-17
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发表时间：
2018
影响因子：
5.4
通讯作者：
Nunberg,JackH
中科院分区：
文献类型：
--
作者：
York,Joanne;Nunberg,JackH
Junín病毒的Lid#1株是使用在非宿主动物和培养细胞中连续传代的常规减毒策略开发的。阿根廷使用减毒活疫苗，以保护处于危险中的个体免受阿根廷出血热的侵害，但它尚未在美国获得许可。最近的研究已经揭示，PD#1减毒完全依赖于病毒包膜糖蛋白复合物（GPC）的融合亚基（GP 2）中位置427处的苯丙氨酸至异亮氨酸的取代，从而引起了关于毒力返强的可能性的担忧。在这项研究中，我们报告的鉴定和表征的减毒F427 I突变GP 2和赖氨酸到丝氨酸的突变在位置33的稳定信号肽（SSP）亚基的GPC基因内上位相互作用，我们证明了这种相互作用的效用，在创建一个进化障碍，对逆转的致病基因型。在野生型F427残基的存在下，K33 S突变废除了异位表达的GPC在内体pH值下介导膜融合的能力。这种缺陷是由衰减F427 I突变拯救的。我们表明，携带K33 S GPC的重组重组病毒1号（rCan）病毒在细胞培养条件下是活的，并保留其减毒基因型，该条件易于选择亲本rCan病毒中的逆转。如果回复突变为F427提供了增加rCan适应性的途径，则K33 S-GPC rCan的回复突变可能是致命的。因此，K33 S和F427 I之间的上位相互作用可以最大限度地减少逆转的可能性，并提高第二代Junín病毒1号疫苗的安全性。重要信息Junín病毒1号减毒活疫苗株用于预防阿根廷出血热。最近的研究发现，在病毒包膜糖蛋白复合物（GPC）的一个单一的错义突变是负责减毒提高了前景的致病性容易逆转。在这里，我们描述了GPC亚基之间的遗传相互作用，在进化上迫使保留的衰减突变。通过将这种二次突变纳入到PD#1 GPC中，我们希望将逆转的可能性降至最低，并提高第二代PD#1疫苗的安全性。类似的方法可以指导针对拉沙和其他沙粒病毒出血热的减毒活疫苗的设计。
The Candid#1 strain of Junín virus was developed using a conventional attenuation strategy of serial passage in nonhost animals and cultured cells. The live-attenuated Candid#1 vaccine is used in Argentina to protect at-risk individuals against Argentine hemorrhagic fever, but it has not been licensed in the United States. Recent studies have revealed that Candid#1 attenuation is entirely dependent on a phenylalanine-to-isoleucine substitution at position 427 in the fusion subunit (GP2) of the viral envelope glycoprotein complex (GPC), thereby raising concerns regarding the potential for reversion to virulence. In this study, we report the identification and characterization of an intragenic epistatic interaction between the attenuating F427I mutation in GP2 and a lysine-to-serine mutation at position 33 in the stable signal peptide (SSP) subunit of GPC, and we demonstrate the utility of this interaction in creating an evolutionary barrier against reversion to the pathogenic genotype. In the presence of the wild-type F427 residue, the K33S mutation abrogates the ability of ectopically expressed GPC to mediate membrane fusion at endosomal pH. This defect is rescued by the attenuating F427I mutation. We show that the recombinant Candid#1 (rCan) virus bearing K33S GPC is viable and retains its attenuated genotype under cell culture conditions that readily select for reversion in the parental rCan virus. If back-mutation to F427 offers an accessible pathway to increase fitness in rCan, reversion in K33S-GPC rCan is likely to be lethal. The epistatic interaction between K33S and F427I thus may minimize the likelihood of reversion and enhance safety in a second-generation Candid#1 vaccine.IMPORTANCEThe live-attenuated Candid#1 vaccine strain of Junín virus is used to protect against Argentine hemorrhagic fever. Recent findings that a single missense mutation in the viral envelope glycoprotein complex (GPC) is responsible for attenuation raise the prospect of facile reversion to pathogenicity. Here, we characterize a genetic interaction between GPC subunits that evolutionarily forces retention of the attenuating mutation. By incorporating this secondary mutation into Candid#1 GPC, we hope to minimize the likelihood of reversion and enhance safety in a second-generation Candid#1 vaccine. A similar approach may guide the design of live-attenuated vaccines against Lassa and other arenaviral hemorrhagic fevers.