Fig. 4

Immunogenicity evaluation of inactivated Bb in mice. A Immunization procedures in mice. B IgG antibody levels against the WH1218 strain on days 0, 14 and 28 after immunization with eight different inactivated strains. C Survival curve of mice after immunization with eight different inactivated Bb strains. Ns, not significant; *, p < 0.05; **, p < 0.01; ***, p < 0.001, and ****, p < 0.0001