School of Basic Medicine, Ningxia Medical University, Ningxia Key laboratory of Clinical and Pathogenic Microbiology, General Hospital of Ningxia Medical University, Yinchuan 750004, China. *Corresponding author, E-mail: [Email]
Objective To investigate the roles of Th1 cytokines tumor necrosis factor α (TNF-α), interferon gamma (IFN-γ) and multifunctional T cells in nucleotides binding oligomer domain 2 knockout (NOD2-/-) mice infected with Mycobacterium tuberculosis (MTB) H37Ra. Methods Mouse models of pulmonary infection were established by tracheal instillation of MTB strain H37Ra into NOD2-/- mice and C57BL/6 mice (n=10 each group). Lung tissues were removed and stained by HE staining and pathological scores were evaluated 4 weeks after infection. The levels of TNF-α and IFN-γ in the lung homogenates were detected by ELISA, and the ratio of multifunctional CD4+ T and CD8+ T cells in the spleen were examined by flow cytometry. Results MTB infection promoted lung inflammation of NOD2-/- mice. The levels of TNF-α and IFN-γ in the lung tissues of NOD2-/- mice increased. Compared with normal saline group, TNF-α+, IFN-γ+ cells and TNF-α+IFN-γ+ cells in CD4+/CD8+T cells significantly increased in NOD2-/- mice and C57BL/6 mice after the infection. TNF-α+CD4+T cells, IFN-γ+CD4+T cells and IFN-γ+CD8+T cells in MTB-infected NOD2-/- mice were significantly higher than those in MTB-infected C57BL/6 mice. Conclusion H37Ra can induce Th1 immune response in NOD2-/- mice.