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目的 评价幽门螺杆菌 (Hp)多种功能蛋白致T细胞凋亡的能力 ,以探求它们在Fas/FasL介导的机体T细胞耐受中的作用 ,为Hp疫苗研制寻求安全有效的免疫原。方法 应用JAM技术对cagA阳性Hp及同源基因突变株、重组尿素酶、粘附素HpaA及外膜蛋白Hop2 5、35、38致T细胞系凋亡的能力进行了比较 ;应用流式细胞术对上述因素特别是cagA阳性菌株诱导T细胞FasL表达的能力进行了检测 ;应用金属蛋白酶抑制剂和蛋白合成抑制剂分别提高和降低Hp介导的T细胞凋亡 ,以证实其与FasL合成的关系。结果 HpcagA阳性株无论在提高T细胞表达FasL还是在诱导T细胞凋亡方面的作用均强于同源基因突变株。Hp抗原制品中尿素酶对T细胞无杀伤能力 ,而Hop38毒性最强 ,Hop2 5、Hop35和HpaA等作用较弱。金属蛋白酶抑制剂提高了cagA阳性Hp致T细胞凋亡的能力 ,而蛋白合成抑制剂Emetine则通过抑制T细胞FasL表达而抑制了Hp介导的T细胞凋亡。结论 cagA蛋白及Hop38能通过调节FasL表达造成T细胞耐受 ;尿素酶、外膜蛋白Hop2 5、Hop35和HpaA不会通过抑制T细胞而导致耐受机制的发生 ,因而可安全应用于疫苗研制。
Objective To evaluate the ability of multiple functional proteins of Helicobacter pylori (Hp) to induce apoptosis of T cells in order to find out their roles in Fas / FasL mediated T cell tolerance and to find a safe and effective immunogen for the development of Hp vaccine. Methods The JAM technique was used to compare the ability of cagA positive Hp, homologous gene mutant, recombinant urease, adhesin HpaA and outer membrane protein Hop2 5, 35, 38 to induce T cell apoptosis. Flow cytometry The above factors, especially the ability of cagA-positive strains to induce the expression of FasL on T cells were detected. The metalloproteinase inhibitors and protein synthesis inhibitors were used to increase and decrease the Hp-mediated T cell apoptosis, respectively, to confirm its relationship with FasL synthesis . Results HpcagA positive strains were stronger than homologous gene mutants in enhancing the expression of FasL on T cells or on the induction of T cell apoptosis. Hp antigen products in urease on T cells without killing ability, and Hop38 the strongest toxicity, Hop2 5, Hop35 and HpaA role weaker. Metalloproteinase inhibitors enhance the ability of cagA-positive Hp-induced T cell apoptosis, while the protein synthesis inhibitor Emetine inhibits Hp-mediated T cell apoptosis by inhibiting T cell FasL expression. Conclusion CagA protein and Hop38 can induce T cell tolerance through regulating the expression of FasL. The urease and OMPs Hop2 5, Hop35 and HpaA do not cause the tolerance mechanism by inhibiting T cells, which makes them safe for vaccine development.