Antigenic Relationships among Porcine Epidemic Diarrhea Virus and Transmissible Gastroenteritis Virus Strains
Antigenic Relationships among Porcine Epidemic Diarrhea Virus and Transmissible Gastroenteritis Virus Strains
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DOI：
10.1128/jvi.03196-14
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发表时间：
2015-03-01
影响因子：
5.4
通讯作者：
Saif, Linda J.
中科院分区：
文献类型：
--
作者：
Lin, Chun-Ming;Gao, Xiang;Saif, Linda J.
猪流行性腹泻病毒（PEDV）和传染性胃肠炎病毒（TGEV）是经济上重要的猪肠致病性冠状病毒。这两种病毒属于冠状病毒科甲型冠状病毒属的两个不同种，在新生仔猪中引起相似的临床症状和病理病变，但推测它们在抗原性上是不同的。本研究采用细胞培养免疫荧光法（CCIF）和病毒中和法（VN）检测了PEDV CV777原型株、三种不同的美国PEDV株（原高毒力PC22A、S indel iwa106和S 197del PC177）和两种具有代表性的美国TGEV株（Miller和Purdue）之间的双向抗原交叉反应性。猪TGEV抗血清不能中和PEDV，反之亦然。猪TGEV Miller超免疫血清与PEDV各毒株的CCIF呈单向交叉反应。酶联免疫吸附试验、单克隆抗体和大肠杆菌表达的重组PEDV和TGEV核衣壳(N)蛋白的免疫印迹以及序列分析表明，PEDV/TGEV N蛋白的N端区域至少有一个表位导致了这种交叉反应性。在生物学上，PEDV CV777菌株比美国PEDV菌株在Vero细胞中诱导更大的细胞融合。与报道的遗传差异一致，CCIF和VN检测结果也显示PEDV CV777与美国菌株之间存在更高的抗原差异。猪肠道冠状病毒PEDV和TGEV在CCIF检测中存在抗原交叉反应的证据，支持这两个物种在进化上相关的观点，但它们是由VN检测确定的不同物种。对pedv或tgev特异性抗原区域的鉴定允许对每种病毒进行更特异性的免疫测定。原型株和当前PEDV株之间的抗原和生物学差异至少可以部分解释PEDV流行的复发。PEDV毒株间的保守抗原性信息对于研制PEDV疫苗以保护猪免受当前高毒性PEDV感染具有重要意义。
Porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis virus (TGEV) are economically important swine enteropathogenic coronaviruses. These two viruses belong to two distinct species of the Alphacoronavirus genus within Coronaviridae and induce similar clinical signs and pathological lesions in newborn piglets, but they are presumed to be antigenically distinct. In the present study, two-way antigenic cross-reactivity examinations between the prototype PEDV CV777 strain, three distinct U.S. PEDV strains (the original highly virulent PC22A, S indel Iowa106, and S 197del PC177), and two representative U.S. TGEV strains (Miller and Purdue) were conducted by cell culture immunofluorescent (CCIF) and viral neutralization (VN) assays. None of the pig TGEV antisera neutralized PEDV and vice versa. One-way cross-reactions were observed by CCIF between TGEV Miller hyperimmune pig antisera and all PEDV strains. Enzyme-linked immunosorbent assays, immunoblotting using monoclonal antibodies and Escherichia coli-expressed recombinant PEDV and TGEV nucleocapsid (N) proteins, and sequence analysis suggested at least one epitope on the N-terminal region of PEDV/TGEV N protein that contributed to this cross-reactivity. Biologically, PEDV strain CV777 induced greater cell fusion in Vero cells than did U.S. PEDV strains. Consistent with the reported genetic differences, the results of CCIF and VN assays also revealed higher antigenic variation between PEDV CV777 and U.S. strains.IMPORTANCEEvidence of antigenic cross-reactivity between porcine enteric coronaviruses, PEDV and TGEV, in CCIF assays supports the idea that these two species are evolutionarily related, but they are distinct species defined by VN assays. Identification of PEDV-or TGEV-specific antigenic regions allows the development of more specific immunoassays for each virus. Antigenic and biologic variations between the prototype and current PEDV strains could explain, at least partially, the recurrence of PEDV epidemics. Information on the conserved antigenicity among PEDV strains is important for the development of PEDV vaccines to protect swine from current highly virulent PEDV infections.