Abstract: Objective To investigate the anti tuberculosis protection immunological mechanism of M.Vaccae in terms of gene level.Methods BALB/C mice were randomly divided into three groups:group of tuberculosis model(A);group that challenged with H₃₇Rv by their tail veins and immunized by M.Vaccae(B)and group of control mice(N).All mice were killed after four weeks infected.with pathological slices stained with HE,using lungs of mice and spleen of mice and make RT-PCR detect the mRNA expression of IFN-γ and IL-4 were evaluated.Results The mRNA expression of IFN-γ were detected in group A,B and N,but group B was the strongest among them.Only group A can detect the mRNAA expression of IL-4.The lung lesions of group B was milder and less than the group A.Conclusion M.Vaccae can improve the anti tuberculosis protection by prompting the mRNA expression of IFN-γ and inhibiting that of IL-4.

Key words: Tuberculosis, RT-PCR, Interferon-γ, Interleukin-4