SARS冠状病毒结构蛋白在血清学诊断中潜在应用价值的比较

为了确定特异的SARS抗体检测抗原，比较了SARS冠状病毒(SARS-CoV)主要结构蛋白与SARS患者血清的反应性。从SARS死亡患者的肺组织提取的总RNA为模板，用RT-PCR技术分别扩增S、N、M和E4种结构蛋白基因，对3种S截短突变体和N、M、E的重组蛋白在大肠杆菌中进行表达。以表达的蛋白为抗原，应用Western blot跟踪检测11例SARS患者血清54份。结果显示：SARS—CoV的重组N蛋白和s蛋白有很强的抗原性，s蛋白的3个区段的抗原性强弱存在差异，S3抗原性强于S1和s2；在患病第1周、2周、3周及3周以上，N蛋白和s3蛋白抗体检出率分别为40％、65。2％、100％、100％和40％、61％、76.2％、100％；提示SARS-CoV重组N蛋白和S3蛋白在SARS的血清学诊断中有一定的应用价值。

Comparison of Potentials of Structural Proteins of SARS-associated Coronavirus for Serological Diagnosis

To identify the sensitive antigens which are suitable for serological diagnostic tests of severe acute respiratory syndrome (SARS),we compared the reactivity of the main structural proteins of SARS-associated coronavirus (SARS-CoV) with the sera from SARS patients. The cDNAs encoding structural proteins M, N, E and 3 truncated forms of S protein (S1, S2 and S3) of SARS-CoV were respectively amplified by RT-PCR using the total RNA extracted from the lung tissue of a dead SARS case and expressed in Escherichia coli (E.coli).By using the recombinant proteins as antigens, the relevant IgG antibodies were detected in 54 serum samples of 11 SARS patients by Western blot. The results showed that the recombinant proteins N, S1, S2 and S3 were strong antigens, but the antigenicity of the three truncated S proteins was different. The positive rate of IgG antibody to S3 protein was the highest, whereras that to S2 was the lowest in the Western blot analysis. The positive rates of IgG antibody against recombinant proteins N and S3 were both 40% in the first week of disease onset, 65.2% and 61% in the second week, 100% and 76.2% in the third week, respectively, and both were 100% after 3 weeks. These results imply that the recombinant proteins N and S3 are the potentially useful antigens in serological diagnosis of SARS.