奶牛乳房炎重要候选疫苗蛋白的抗原表位分析及三联重组表位疫苗的氨基酸序列设计

摘要

为设计奶牛乳房炎三联重组表位多肽疫苗，选取奶牛乳房炎3种主要感染菌的候选疫苗蛋白：金黄色葡萄球菌的Ebps与ClfA，大肠埃希菌的OmpA与OmpC，链球菌的SIP与PGK，通过ABCpred和BepiPred方案，预测获得每种蛋白各有2个优势B细胞表位；利用神经网络与量化矩阵法预测蛋白的CTL表位。结果显示，SIP蛋白无CTL表位，其余蛋白均存在1个CTL细胞表位；采用MHC-Ⅱ类分子结合肽在线程序预测蛋白的Th表位，结果发现每种蛋白各有1个Th细胞表位。使用DNASTAR软件分析6个蛋白的二级结构，结果发现，预测获得的B／T细胞表位大多处于蛋白易于产生表位的暴露表面、无规则卷曲与转角等位置。再通过Protean程序重组拼接获得的B／T细胞抗原表位，最终设计获得抗原性较好的三联表位疫苗氨基酸序列。为新型奶牛乳房炎三联表位疫苗的研制奠定基础。%In order to design cow mastitis triple recombinant epitope polypeptide vaccine, six candidate vaccine pro-teins were selected, which were from three main pathogens of cow mastitis, concluding Ebps and ClfA of Staphylococ⁃cus aureus, OmpA and OmpC of Escherichia coli, SIP and PGK of Streptococcus. Using ABCpred and BepiPred pre-diction program, each protein had 2 B cell epitopes. CTL cell epitopes were obtained by the prediction method of quantitative matrix and artificial neural network, the results showed that the SIP protein had no CTL cell epitope, and there was 1 CTL cell epitope to other proteins. Th cell epitopes were gained using an online server prediction for MHC class Ⅱ peptide binding affinity, the results showed that each protein had 1 Th cell epitope. DNASTAR soft-ware was used to analyze the secondary structure for the six proteins, and the results showed that most of the B/T cell epitopes were located on the exposed surface, the random coil and the corner. The B/T cell epitopes were recom-posed by DNASTAR Protean software, and triple epitope vaccine amino acid sequence holding better antigen was de-signed finally. These laid the foundation for the novel triple epitope vaccine of cow mastitis.