Aim: To dynamically observe the immune responses in mice administrated with a recombinant Bifidobacteria bifidum (Bb)-Eg95-EgA31 vaccine of Echinococcus granulosus.
Methods: BALB/c mice were immunized orally or intranasally by the vaccine. At indicated times after vaccination, the levels of serum IgG, IgG subclass and IgE were determined by ELISA. The levels of IL-12, IFN-gamma, TNF-alpha and IL-10 were measured by ELISA in the supernatant of cultured splenocytes. Proliferation of splenocytes was tested by MTT. The percentage of spleen CD4+ and CD8+ cells was determined by flow cytometry(FCM).
Results: The orally immunized mice achieved IgG and IgG3 peaks on 8th week post vaccination, IgG2a peak on 2nd week, IgG2b and IgG1 peaks on 6th week, and IgE peak on 10th week. IFN-gamma and TNF-alpha reached highest level on 4th week, IL-12 on 2nd week, and IL-10 on 6th week. Splenocytes proliferated fastest on 6th week. The percentage of CD4+ cells was peaked on 6th week, while the percentage of CD8+ cells had no obvious change. The intranasally immunized group achieved peaks of IgG, IgG2b and IgE on 10th week, IgG2a peak on 6th week, and peaks of IgG1 and IgG3 on 8th week. IFN-gamma and IL-12 reached highest level on 2nd week, TNF-alpha on 4th week, and IL-10 on 8th week. Splenocytes proliferated fastest on 6th week. The percentage of CD4+ cells was peaked on 6th week, while the percentage of CD8+ cells had no obvious change.
Conclusion: The recombinant Bb-Eg95-EgA31 vaccine of Echinococcus granulosus induced effective immune responses in mice by either oral vaccination or intranasal inoculation. Our data showed the better immunogenicity of oral vaccination.