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

OBJECTIVE:To investigate the dynamic changes of the immune responses in mice immunized with a recombinant (Bifidobacterium bifidum, Bb) (pGEX-Sj14-3-3) vaccine of Schistosoma japonicum. METHODS:BALB/c mice were immunized 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 cytometry. The production of IFN-γ, IL-12, TNF-α and IL-10 were quantified by ABC-ELISA in the supernatant of cultured splenocytes. RESULTS:The orally immunized mice achieved the peaks of IgG, IgG1, 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, respectively. IFN-γ, IL-12, TNF-α and IL-10 reached the highest levels at 8, 8, 6 and 4 weeks, respectively. The intranasally immunized group reached to the peaks of IgG, IgG1, IgG2a, IgG2b, IgG3, IgE and IgA at 4, 6, 4, 4, 8, 10 and 8 weeks, respectively. The proportion of CD4(+);T cells peaked at 8 weeks, while CD8(+);T cells at 4 weeks. IFN-γ, IL-12, TNF-α and IL-10 achieved the highest values respectively at 2, 2, 4 and 4 weeks. CONCLUSION:The recombinant Bb(pGEX-Sj14-3-3) vaccine could induce effective immune responses in mice by either oral vaccination or intranasal inoculation. The better immunogenicity of intranasal vaccination is proved.