Developing recombinant coronavirus vaccines for SARS

描述(申请人提供)：最近流行的严重急性呼吸系统综合症(SARS)是由一种新的冠状病毒SARS-CoV引起的。在疫情期间，全球报告了超过8000例SARS病例和812例死亡。由于SARS的传播容易和严重，对公众健康构成了巨大的威胁，并造成了重大的经济损失。它还给美国带来了严重的生物防御风险。到目前为止，还没有有效的抗SARS药物或疫苗可用。这项拟议研究的长期目标是开发一种有效的疫苗来预防未来的SARS疫情。目前从动物冠状病毒及其各自宿主的研究中获得的信息表明，最有希望的SARS疫苗将是基于冠状病毒的活疫苗。然而，尽管开发一种减毒的SARS-CoV活疫苗是可能的，但这是一种长期的方法，其结果是不可预测的。此前，P.I.从人类身上分离出一种肠道冠状病毒(称为HECoV)，这种病毒与急性轻度腹泻有关，但在儿童中没有其他严重的临床症状。最近我们实验室的全基因组序列分析显示，HECoV分离株与牛冠状病毒关系最密切。根据常见的粘膜免疫系统的原理，口服免疫的抗原刺激在诱导对呼吸道病原体的免疫方面往往是非常有效的。因此，P.I.建议开发一种表达SARS-CoV抗原蛋白的重组肠道HECoV作为SARS口服疫苗。提出了五个目标：(1)研制表达SARS-CoV S蛋白和其他蛋白的重组肠道HECoV；(2)在细胞培养中鉴定重组疫苗的生物学和遗传学特性；(3)评价重组疫苗在非人类灵长类动物中的安全性和免疫原性；(4)评价重组疫苗在非人类灵长类动物中的安全性、免疫原性和有效性；(5)建立用于生产人类临床试验(GMP)疫苗的细胞培养工艺。这些研究将为开发有效的SARS疫苗提供关键信息。这种反向遗传系统的发展将有助于研究冠状病毒的分子发病机制，并可能为开发其他严重传染病(如艾滋病)的疫苗提供潜在的途径。

DESCRIPTION (provided by applicant): The recent epidemic of the severe acute respiratory syndrome (SARS) is caused by a novel coronavirus, SARS-CoV. During the epidemic, more than 8,000 SARS cases and 812 deaths have been reported worldwide. With an ease of transmission and severity of the disease, SARS poses a great threat to public health and causes significant economic loss. It also presents a serious biodefense risk to the United States. To date, no effective anti-SARS drugs or vaccines are available. The long-term goal of this proposed research is to develop an efficacious vaccine for preventing future SARS epidemic. Current information obtained from studies on animal coronaviruses and their respective hosts suggests that the most promising vaccine for SARS would be a coronavirus-based live vaccine. However, the development of an attenuated, live SARS-CoV vaccine, though possible, is a long-term approach with an unpredictable outcome. Previously, the P.I. has isolated an enteric coronavirus from humans (termed HECoV), which is associated with acute, mild diarrhea but with no other severe clinical symptoms in children. Recent sequence analysis of the entire genome from our laboratory revealed that the HECoV isolate is most closely related to bovine coronavirus. Based on the tenet of a common mucosal immune system, antigenic stimulation by oral immunization is often very effective in inducing immunity to respiratory pathogens. Therefore, the P.I. proposes to develop a recombinant enteric HECoV expressing the antigenic proteins of the SARS-CoV as oral vaccines for SARS. Five aims are proposed: (1) to develop recombinant enteric HECoV expressing the ectodomain of the spike and other proteins of the SARS-CoV; (2) to characterize the biologic and genetic properties of the recombinant vaccines in cell culture; (3) to evaluate the safety and immunogenicity of the recombinant vaccines in germ-free calves; (4) to evaluate the safety, immunogenicity, and efficacy of the recombinant vaccines in non-human primates; (5) to develop a cell culture process for production of vaccines for human clinic trial (GMP).These studies will provide critical information for the development of an efficacious vaccine for SARS. The development of such a reverse genetic system will facilitate studies on molecular pathogenesis of coronaviruses and may provide potential avenues for development of vaccines for other severe infectious diseases such as AIDS.