幽门螺杆菌重组粘附素rHpaA生物学活性及免疫原性的体外评价

目的：体外评价幽门螺杆菌（Hp)重组粘附素rHpaA的生物学活性及免疫原性，探讨其在Hp疫苗应用中的可行性。方法：流式细胞术和光镜定量计数法检测rHpaA及其抗体对Hp与胃上皮细胞粘附的影响；ELISA法测定Hp感染者血清中抗HpaA抗体,^3H-TDR掺入法测定人外周血淋巴细胞（PBL）对rHpaA的增殖反应，评价rHpaA对体液和细胞免疫的细胞；流式细胞术检测rHpaA对T辅助细胞（Th）表型的选择作用，探讨rHpaA可能的免疫机制。结果rHpaA和抗rHpaA抗血清均能部分阻断Hp与胃上皮细胞系的粘附；ELISA法能检测出Hp阳性患者血清中存在抗HpaA抗体，检测出率与Hp超声破碎抗原（HpSON)包被下的检出率相近（50%vs54%,P＞0．05）；不论培养基中是否加入IL－2，rHpaA均可刺激Hp PBL的增殖（P＜0．05）；Hp阳性或阴性PBL细胞与rHpaA孵育后均能显著提高IL－4阳性T细胞比例（P＜0．05）。结论HpaA是具有免疫原性的Hp菌体成分，且能选择性增加Th2细胞比例，有望成为Hp疫苗研制中一种有效的新抗原。

In vitro study of the biological activities and immunogenicity of recombinant adhesin of Heliobacter pylori rHpaA

Objective To evaluate the biological activities and immunogenicity of recombinant adhesin of Helicobacter pylori rHpaA in vitro and the feasibility of its application in development of Heliobacter pylori vaccine. Methods The effect of rHpaA and its antibody on the adhesion of H.pylori to human gastric epithelial cell lines was investigated by flow cytometry and light microscopy. ELISA was used to measure the HpaA-specific antibodies in sera of H.pylori-infected patients. The proliferation of peripheral blood lymphocytes (PBL) in response to rHpaA was examined by 3H-TDR incorporation test. Flow cytometry was adopted to detect the selective proliferation effect of rHpaA on different phenotypes of T helper cells in PBLs. Results Both rHpaA and anti-HpaA serum partially inhibited the adhesion of Heliobacter pylori to gastric epithelial cell lines. Anti-HpaA antibodies (coated with rHpaA) were detected in sera from H.Pylori-infected patients with a detection rate similar to that of anti-HpaA antibodies coated with HpSON (50% Vs 53.75%, P>0.05). The rHpaA was capable of stimulating the proliferation of PBL (P<0.05), no matter IL-2 was added into the culture medium or not. Both Hp positive and negative PBLs, after incubation with rHpaA, could significantly raise the proportion of IL-4 positive T cell (Th2 cell) (P<0.05). Conclusion HpaA is an immunogenic surface protein of H.pylori and can selectively increase the proportion of Th2 cells in vitro and is a hopeful new antigen in the development of H.pylori vaccine.