【Objective】To test the immunogenicity and immunoreactivity of recombinant S .lactis . 【Method】The intrag ast ric immunization w as perfo rmed individually w ith gene recombinant S .lact is (HL 107)

S .lact is (LM 0230)and S .mutans Ingbrit t in BALB/c mice .Saliva and serum samples were assayed by enzyme-linked immunosorbent assay (ELISA).【Result】The recombinant S .lact is were more effective in inducing PAc-specif ic serum IgG antibodies in BALB/c mice than the other g roups w hen given intragast rically(P <0.05).The level of PAc-specific salivary IgA in the group of recombinant S .lactis w as higher than the other g roups (P <0.01)except S .mutans Ingbrit t (P >0.05).PAc-specif ic salivary IgG and PAc-specific serum IgA in all groups show ed no difference (P >0.05).【Conclusion】The gene recombinant S .lact is possesses an immunogenicity of S .mutans surface protein ant igen and induces specific immune response in BALB/c mice .