PEDV中国流行株和疫苗株S蛋白免疫反应性差异分析

Differences in immunoreactivity of spike protein between porcine epidemic diarrhea virus variant and CV777 vaccine strain

为分析PEDV流行株和疫苗株S基因差异对疫苗免疫效果影响,分别在大肠杆菌中表达PEDV流行株CH/ZMDZY/11与疫苗株CV777S蛋白差异较大的N端（22～380aa）区域（SA）,将纯化的SA蛋白免疫小鼠获得多克隆抗体,并以SA蛋白为抗原,通过Western Blot及间接ELISA的方法检测2种蛋白与多克隆抗体的反应性差异。结果表明,抗PEDV疫苗株SA蛋白（YSA）多抗与疫苗株SA蛋白的反应性明显高于与流行株SA蛋白（LSA）的反应性;与此相反,抗PEDV流行株SA蛋白多抗与流行株SA蛋白的反应性明显高于与疫苗株SA蛋白的反应性。研究结果提示,PEDV S蛋白22～380aa区域存在差异性抗原表位,PEDV流行株和疫苗株S基因的差异可能是导致基于CV777疫苗株的PED疫苗免疫效果不好的原因。本研究将为开发PEDV流行株亚单位疫苗用于预防临床PEDV流行株的感染提供理论依据。

In order to analyze the effects of genetic differences of spike gene of porcine epidemic diarrhea virus（PEDV）on the efficacy of its vaccines,the spike gene N-terminal（22～380aa）domain of PEDV epidemic strain CH/ZMDZY/11 and CV777vaccine strain,which was designated as LSA and YSA,was expressed in E.coli respectively.Purified spike proteins were used to immunize Kunming mice to prepare anti-spike polyclonal antibodies.Cross-immunoreactivity between antiLSA and anti-YLA antibody was verified by ELISA and Western blot.In ELISA,anti-LSA antibody showed significant higher immunoreactivity with LSA than that of YSA,and anti-YSA antibody showed significant higher immunoreactivity with YSA than that of LSA.In Western blot,anti-LSA antibody couldnt recognize YSA and anti-YSA antibody couldnt recognize LSA.The results suggested that there were different epitopes in 22～380aa region of PEDV S protein.The less efficacy of CV777-based vaccine against epidemic PEDV strain could be due to these different epitopes.This study will provide a theoretical base for developing subunit vaccine for PED prevention.