SARS-CoV-2、HCoV-OC43和HCoV-HKU1棘突蛋白抗原表位分析

Analysis of spike protein antigenic epitopes of SARS-CoV-2,HCoV-OC43 and HCoV-HKU1

目的探讨严重急性呼吸综合征冠状病毒2(SARS-CoV-2)、人冠状病毒(HCoV)-OC43和HCoV-HKU1棘突(S)蛋白抗原表位的特征。方法从美国国立生物技术信息中心(NCBI)数据库中下载SARS-CoV-2、HCoV-OC43、HCoV-HKU1的S蛋白序列和空间结构,进行多序列比对,采用Protean软件、IEDB软件和SYFPEITHI软件进行抗原表位预测。结果从NCBI数据库中收录的65条完整的SARS-CoV-2 S蛋白序列中选取9条S蛋白无氨基酸重复的序列,以QHZ87592.1为标准序列,其他8条S蛋白序列共出现8个位点的突变和1个位点的缺失,但均未分布在受体结合域(RBD)区域。SARS-CoV-2与HCoV-OC43、HCoV-HKU1的S蛋白RBD区域有明显差异。3种冠状病毒S蛋白S2亚基的氨基酸序列相似性较高。S蛋白的B细胞抗原表位主要集中在S1亚基,3种冠状病毒之间无相似性。HCoV-HKU1、HCoV-OC43的S蛋白S2亚基T细胞表位与SARS-CoV-2比较,均有一定的相似性,最高相似度为70.0%。结论S2亚基的T细胞抗原表位可能是3种冠状病毒的共同抗原,HCoV-OC43和HCoV-HKU1致敏的记忆T淋巴细胞可能对SARS-CoV-2感染有交叉性的细胞免疫功能。

Objective To study the characteristics of spike(S)protein antigenic epitopes of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),human coronavirus(HCoV)-OC43 and HCoV-HKU1.Methods The S protein sequences and spatial structures of SARS-CoV-2,HCoV-OC43 and HCoV-HKU1 were obtained from the National Center for Biotechnology Information(NCBI).Multiple sequence alignment was used to analyze these protein sequences.Protean,IEDB and SYFPEITHI were used to predict epitopes.Results From the 65 complete SARS-CoV-2 S protein sequences included in NCBI,9 sequences of S proteins with no amino acid repeats were selected,and QHZ87592.1 was used as the standard sequence.The other 8 S protein sequences had 8 site mutations and 1 site deletion,but none of them were distributed in receptor binding domain(RBD).RBD regions of S protein of SARS-CoV-2,HCoV-OC43 and HCoV-HKU1 were different.The amino acid sequences of the S2 subunits of the 3 coronavirus S proteins were highly similar.The B cell antigenic epitopes of S protein were mainly concentrated in S1 subunit,and there was no similarity among the 3 coronaviruses.The T cell antigenic epitopes of the S2 subunit of HCoV-HKU1 and HCoV-OC43 were all similar to that of SARS-CoV-2,and the highest similarity was 70.0%.Conclusions The T cell antigenic epitopes of the S2 subunit may be a common antigen of the 3 coronaviruses.Memory T lymphocytes sensitized by HCoV-OC43 and HCoV-HKU1 might play roles in heterosubtypic immunity to SARS-CoV-2.