日本血吸虫重组Bb(pGEX-Sj14-3-3)疫苗免疫BALB/c小鼠诱导免疫应答的动态检测

Dynamic changes of immune responses in BALB/c mice immunized with a recombinant Bb(pGEX-Sj14-3-3) vaccine of Schistosoma japonicum

目的研究日本血吸虫重组双歧杆菌属两歧双歧杆菌(Bb)(pGEX-Sj14-3-3)疫苗免疫小鼠后其免疫应答的动态变化。方法将重组疫苗分别采用口服灌胃和鼻内接种免疫BALB/c小鼠,分别于免疫后2、4、6、8、10、12、14、16、18、20和22周ELISA法测小鼠血清中IgG及其亚类、IgE和IgA及脾细胞培养液中IFN-γ、IL-12、TNF-α和IL-10水平;MTT法测定脾细胞增殖;流式细胞仪检测脾细胞凋亡率及CD4+和CD8+T细胞亚群百分率。结果口服组血清IgG、IgG1、IgG2a、IgG2b、IgG3、IgE和IgA水平分别在免疫后8、6、6、4、8、10和6周达峰值。脾淋巴细胞增殖和凋亡水平均在免疫后4周达峰值;CD4+T细胞于8周达峰值,CD8+T细胞于14周达峰值。IFN-γ、IL-12、TNF-α和IL-10水平分别于8、8、6和4周达峰值。鼻内接种组血清IgG、IgG1、IgG2a、IgG2b、IgG3、IgE和IgA分别于4、6、4、4、8、10和8周达峰值。脾淋巴细胞增殖及凋亡水平也均在4周达峰值;CD4+T细胞于8周达峰值,CD8+T细胞于4周达峰值。IFN-γ、IL-12、TNF-α和IL-10水平分别于2、2、4和4周达峰值。口服及鼻腔内接种是两种较好的免疫途径,且后者优于前者。结论该疫苗可诱导小鼠产生有效的免疫应答。

Objective To investigate the dynamic changes of the immune responses in mice immunized with a recombi- nant （ Bifidobacterium bifidum, Bb） （pGEX-Sj14-3-3） vaccine of Schistosoma japonicum. Methods BALB/c mice were im- munized orally or intranasally by the vaccine. At the interval of every two weeks up to the 22nd week of post-vaccination, the levels of serum IgG, IgG subclass, IgE and IgA were determined by ELISA. Proliferation of splenocytes was observed with MTT assay. The percentage of T-lymphocyte subsets and the rate of apoptotic splenocytes were determined by flow cytome- try. The production of IFN--y, IL-12, TNF-a and IL-lO were quantified by ABC-ELISA in the supernatant of cultured spleno- cytes. Results The orally immunized mice achieved the peaks of IgG, IgGl, IgG2a, IgG2b, IgG3, IgE and IgA at 8, 6, 6, 4, 8, 10 and 6 weeks, respectively. The proliferation and the apoptosis rates of splenocytes came to peaks at 4 week, so did the intranasally immunized group. The percentages of CD4 ＋ T cells and CD8 ~ T cells peaked at 8 and 14 weeks, respective- ly. IFN-y, IL-12, TNF-a and IL-10 reached the highest levels at 8, 8, 6 and 4 weeks, respectively. The intranasally immu- nized group reached to the peaks of IgG, IgG1, IgG2a, IgG2b, IgG3, IgE and IgA at4, 6, 4, 4, 8, 10 and 8 weeks, respec- tively. The proportion of CD4~T cells peaked at 8 weeks, while CD8 ＋T cells at 4 weeks. IFN-y, IL-12, TNF-a and IL-10 achieved the highest values respectively at 2, 2, 4 and 4 weeks. Conclusion The recombinant Bb（pGEX-Sjl4-3-3） vaccine could induce effective immune responses in mice by either oral vaccination or intranasal inoculation. The better immunogenic- ity of intranasal vaccination is proved.