大肠杆菌O157∶H7Ivy蛋白表位多肽及免疫原性分析

摘要

To evaluate the feasibility of synthetic polypeptides O157∶H7 Ivy146—157 as a vaccine antigen,a bioinformatics method was employed to analyze the secondary structures,hydrophilici-ty 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∶H7 R14 strain 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 in-dicated that polypeptides Ivy146—157 could induce a strong humoral and celluar immune re-spond,and it would provide a theory as a vaccine antigen for further researches.%为评价合成的 O157∶H7 Ivy146—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∶6400，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。