Th1反应及γ-干扰素在幽门螺杆菌疫苗免疫保护中的作用

目的　探讨磷酸胞苷酰寡核苷酸 (CpG ODN)作为幽门螺杆菌 (Hp)疫苗佐剂的作用及Th1反应与γ 干扰素 (γ IFN)在免疫保护作用中的角色。方法　以Hp全菌超声粉碎物 (WCS)为抗原 ,CpG ODN为佐剂经鼻道或口服免疫小鼠 ,采用 5× 10 6CFU和 5× 10 8CFUHp两个菌量攻击小鼠 ,2周及 8周处死小鼠鉴定感染及炎症情况 ,收集小鼠血清、唾液、胃液 ,ELISA法检测血清中IgG、IgG1、IgG2a及IgA水平和唾液、胃液中IgA水平。流式细胞术检测脾细胞内CD+ 4 和CD+ 8T细胞分泌γ IFN和白细胞介素 4 (IL 4 )的水平。结果　当细菌攻击量由 5× 10 8Hp降至 5× 10 6Hp时 ,滴鼻WCS/CpG组保护率由 70 %提高至 90 % ,无免疫对照组的感染率也由 10 0 %降至 80 %。细菌攻击后2周及 8周时 ,滴鼻WCS/CpG ODN组的血清IgG和IgG2a均高于对照组 (P <0 0 5 ) ;CD+ 4 细胞和CD+ 8细胞中的γ IFN水平也均高于其他各组 (P <0 0 5 )。结论　CpG ODN可作为Hp疫苗佐剂成分 ,其免疫保护作用与Th1反应和γ IFN相关。

The role of Th1-type response and gamma-interferon in the protection induced by Helicobacter pylori vaccine

OBJECTIVE: To determine whether CpG-oligodeoxynucleotide (CpG-ODN) can be an adjuvant for the development of a Helicobacter pylori (H. pylori) vaccine, and explore the role of Th1-type response and gamma-interferon (gamma-IFN) in protection induced by vaccine. METHODS: Mice were intranasally or orally immunized with H. pylori whole cell sonicate (WCS) and CpG-ODN and challenged with 5 x 10(6) or 5 x 10(8) organisms. The mice were killed 2 and 8 weeks later respectively, the sera, saliva, gastric juice were collected to measure the concentrations of IgG, IgG1, IgG2a and IgA by ELISA, their spleen cells were isolated for analysis of intracellular gamma-IFN and interleukin-4 (IL-4) by flow cytometry. RESULTS: The prevention rate against H. pylori infection was 70% in mice intranasally immunized with WCS plus CpG-ODN and challenged with 5 x 10(8) CFU H. pylori, and 90% in those challenged with 5 x 10(6) CFU H. pylori. Significantly higher levels of IgG1 and IFN-gamma were found in the mice immunized with WCS/CpG than those in sham-immunized controls (P < 0.05). Spontaneous elimination of H. pylori infection occurred in two of ten sham-immunized mice, whose IgG1 and IFN-gamma levels were higher than those of other sham-immunized ones. CONCLUSION: CpG-Oligodeoxynucleotide is a potent adjuvant of vaccine against H. pylori, and Th1-type response and gamma-IFN are highly associated with the protective effect.