口蹄疫病毒VP1 T、B细胞表位与大肠杆菌肠毒素融合蛋白的免疫保护性研究

Study on the Immune Protective Effect of the Fusion Protein Including Two Copies of T-cell and B-cell Epitopes of Food-and-mouth Disease Virus VP1 and Enterotoxins of Escherichia coli

作者对O型口蹄疫病毒(FMDV)VP1双拷贝T细胞表位(aa 21-40)、B细胞表位(aa 141-160)融合蛋白2020-2020VP1及其与肠毒素大肠杆菌肠毒素融合后蛋白2020-B-2020和2020-B-2020-STI进行了免疫分析。动物试验表明,用2020-2020VP1、2020-B-2020和2020-B-2020-STI 3种融合蛋白分别免疫动物,免疫动物血清中均可产生针对FMDV的抗体。免疫豚鼠在低浓度FMDV刺激下能够产生特异性T淋巴细胞增殖反应,说明3种融合蛋白都能诱导机体产生FMDV特异性细胞及体液免疫反应。2020-B-2020和2020-B-2020-STI融合蛋白免疫雌鼠能够抵抗大肠杆菌强毒株攻击,免疫保护率如下:2020-B-2020 60%/1.5MLD,2020-B-2020-STI 100%/1.5MLD。2020-B-2020-STI免疫血清中具有STI中和抗体,且融合蛋白不具STI毒性。ELISA结果显示,2020-B-2020和2020-B-2020-STI能与霍乱毒素(cholera toxin)CTB抗体特异性结合。结果表明,2020-B-2020-STI具有开发成为口蹄疫及肠毒素大肠杆菌疫苗的应用价值。

In this study, the fusion proteins including two copies of T-cell epitope（aa21-40） and Bcell epitope（aa141-160） of VP1 of food-and-mouth disease virus typed O and labile enterotoxin B subunit （LTB） and/not stable enterotoxin I （STI） of Escherichia coli were analyzed as candidate vaccine against FMDV and E. coll. The proteins 2020-2020VP1,2020-B-2020 and 2020-B-2020- STI were used to vaccinate guinea pigs, rabbits and 6-8 weeks old BALB/c mice, then the immune responses were observed. The fusion proteins could induce proliferation of spleen T cells in vaccinated guinea pigs, and could elicit FMDV neutralizing antibody. It could be concluded that the three fusion proteins could activate FMDV-special cellular and humoral immune-response simultaneously. At the same time, the fusion proteins 2020-B-2020 and 2020-B-2020-STI could pro- tect mice from challenge of enterotoxigenic E. coli C83902 and the protecting-rate were 60%/1.5 MLD and 100%/1.5 MLD respectively. The fusion protein including STI enterotoxin could induce neutralizing antibody for STI toxin in rabbits, moreover, the fusion protein had no STI toxicity. The fusion proteins 2020-B-2020 and 2020-B-2020-STI could be recognized specially by CTB antibody in ELISA. So that, it can be concluded that the fusion protein 2020-B-2020-STI is potent to be efficient FMDV and ETEC vaccine.