幽门螺杆菌重组粘附素的安全性、免疫原性和生物学活性的体外评价

In vitro evaluation of the safety and biological activity of recombinant Helicobacter pylori blood group antigen-binding adhesin

目的通过体外实验确定重组粘附素(rBabA)的安全性、免疫原性及粘附作用,探讨rBabA在幽门螺杆菌(Hp)疫苗应用中的可行性。方法二苯胺法测定rBabA致T细胞凋亡率,ELISA法测定Hp感染者血清中抗rBabA抗体,MTT法测定T细胞对rBabA的增殖反应,光镜计数法研究rBabA对Hp与胃癌细胞粘附的影响。结果体外安全性实验表明rBabA无明显致BabA抗体阴性者T细胞凋亡的作用,而且可刺激rBabA抗体阳性者T细胞的增殖;ELISA法共检测了38份Hp感染患者血清,rBabA抗体阳性率为18.4%。rBabA能部分阻断Hp与胃癌细胞系的粘附。结论研究表明rBabA是安全的、具有免疫原性的Hp菌体成分,既可以刺激体液免疫,又能够提高细胞免疫,有望成为针对BabA2基因阳性Hp菌株疫苗研制中一种有效的新抗原。

Objective To evaluate the safety and biological activity of recombinant Helicobacter pylori(Hp) blood group antigen- binding adhesin (rBabA ) in vitro so as to investigate the feasibility of using rBabA as a Hp vaccine. Methods ELISA was used to measure rBabA-specific antibody in the serum of Hp-infected patients, and the proliferation of T lymphocytes in response to rBabA was examined by MTT assay. T cell apoptosis induced by rBabA was detected by diphenylamine assay. The effect of rBabA on Hp binding into human gastric carcinoma cell line(MGC-803) was determined by light microscopy. Results rBabA did not induce T cell apoptosis in BabA antibody- negative patients and was capable of stimulating T cell proliferation in rBabA antibody-positive patients. In the serum samples from 38 Hp-infected patients, the rBabA antibody positivity rate was 18.4%. rBabA could partially inhibit the binding of Hp to gastric epithelial cells. Under light microscope, the adhesion of Hp to MGC-803 was significantly inhibited by rBabA in comparison with negative control with PBS pretreatment. Conclusion rBabA proves to be a safe and immunogenic bacterial component of Hp, which stimulates humoral and cellular immunity and can be a hopeful antigen targeting at BabA2 gene-positive Hp strain for the development of Hp vaccine.