大肠杆菌O157∶H7 Ivy蛋白表位多肽及免疫原性分析

Antigen Epitope Peptides and Immunogenicity Analysis of E.coli O157∶H7 Ivy Protein

为评价合成的O157∶H7Ivy146—157多肽作为疫苗抗原的可行性,本试验利用生物信息学方法分析Ivy的二级结构、氨基酸亲水性、蛋白柔性区域、表面可及性和抗原指数,筛选获得1条含有B细胞抗原表位的多肽序列Ivy146—157,进行化学合成。多肽免疫BALB/c小鼠,测定免疫后小鼠的抗体水平及Ivy146—157多肽对小鼠脾淋巴细胞的刺激增殖情况。结果显示,合成的Ivy146—157多肽第3次免疫小鼠后抗体水平达到1∶6 400,制备的Ivy146—157多克隆抗体能够识别天然菌株中的目的蛋白;MTT试验结果显示,Ivy146—157免疫后小鼠脾淋巴细胞增殖明显,与对照组差异显著(P<0.05)。结果表明,Ivy146—157多肽能够诱导机体产生体液免疫和细胞免疫反应,为其作为疫苗用抗原的进一步研究奠定了理论基础。

To evaluate the feasibility of synthetic polypeptides O157∶H7Ivy146—157as a vaccine antigen,a bioinformatics method was employed to analyze the secondary structures,hydrophilicity plot,flexibility plot,surface probability plot and antigenic index of the Ivy.A B-cell epitope peptide sequence was identified and synthesized.BALB/c mice were immunized with Ivy146—157,antibody titers and splenic lymphocytes proliferations in mice were tested.The results showed that the antibody titers were 1∶6 400 after immunized mice three times.And the native Ivy protein of O157∶H7R14strain was identified by polyclone antibody Ivy146—157.The MTT assay results indicated the splenic lyphocytes were increased after immunized polypeptides Ivy146—157,and had significant difference with the control group（P〈0.05）.These results indicated that polypeptides Ivy146—157could induce a strong humoral and celluar immune respond,and it would provide a theory as a vaccine antigen for further researches.