SARS-CoV、229E和OC43的抗原相关性研究

Antigenicity relationship of SARS-CoV,229E and OC43

目的:分析SARS冠状病毒(SARSCoV)和人冠状病毒(229E和OC43)的抗原相关性。方法:制备三株冠状病毒的免疫兔血清及其重组核衣壳(N)蛋白的免疫小鼠血清,分别采用ELISA法、Westernblot和免疫荧光法对免疫血清进行检测以分析三株冠状病毒的抗原相关性。结果:Westernblot结果显示重组N蛋白免疫小鼠血清仅与各自的冠状病毒或重组N蛋白有特异性反应,相互间无交叉反应,而ELISA结果显示OC43重组N蛋白免疫小鼠血清与SARSCoV、229EN蛋白出现了构象抗体的交叉反应。同时,免疫荧光结果显示SARSCoV和OC43免疫兔血清与229E感染细胞存在较明显的交叉反应,但在ELISA、Westernblot结果中全病毒免疫兔血清均仅与各自N蛋白特异性反应,相互间无交叉反应。结论:SARSCoV、229E和OC43N蛋白抗原性在免疫动物血清中不存在交叉反应,而SARSCoV、OC43全病毒免疫血清均和229E出现明显的交叉反应。另外,基因重组的OC43N蛋白与另外二种N蛋白出现重组构形表位的交叉反应,提示以基因重组的蛋白作为诊断试剂,可能会因为蛋白的空间构象发生改变而产生非特异性反应。

Objective：To determine the antigenic relationship between SARS-associated coronavirus（SARS-CoV） and two human coronaviruses（229E and OCA3）. Methods：Hyperimmune rabbit antiserum against HCoV-229E, HCoV-OC43 and SARS-CoV and hyperimmune mouse antiserum against the recombinant N proteins of the coronaviruses were prepared for analyzing the antigenic crossreactivity in these immunized animals sera by Western blot analysis, indirect immunofluoreseent assay（IFA） , and enzyme-linked immunosorbent assay（ELISA）. Results ：The N proteins of HCoV-229E, HCoV-OCA3 and SARS-CoV only reacted strongly and specifically with their corresponding hyperimmune mouse serum and no cross-reactivity was demonstrated between the three N proteins on the Western blot analysis. But the hyperimmune mouse antiserum against the N protein of HCoV-OC43 showed cross-reaction with the N proteins of HCoV-229E and SARS-CoV by ELISA. The N proteins of HCoV-229E, HCoV-OC43 and SARS-CoV also just specifically reacted with their corresponding whole-vires hyperimmune rabbit antiserum by the ELISA and Western blot assays. But obvious crossreaction was observed by IF when the culture cells infected with HCoV-229E were detected using the whole-virus hyperimmune rabbit antiserum against HCoV-OC43 or SARS-CoV. Conclusion ：There is no serological cross reactivity among the hyperimmune sera against the three N proteins, whereas HCoV-229E has obviously cross-reaction with the whole-virus hyperimmune rabbit antiserum against HCoV-OCA3 or SARS-CoV. Nonspecific reaction may occur when the recombinant N proteins was used for diagnosis markers due to the cross reactivity between the recombinant N protein of HCoV-OC43 and the recombinant N protein of HCoV-OC43 or SARS-CoV.