The inflammatory response and T lymphocytes with SLAM expression in macrophages of mice infected with mycobacterium tuberculosis

Objective: This study aims to analyze the levels of inflammatory cytokines, T lymphocytes and signaling lymphocytic activation molecule (SLAM) in a mouse model of mycobacterium tuberculosis (M.tb). Methods: A total of 40 mice were randomly and equally divided into the strain group receiving a tail vein injection of M.tb and the control group with normal saline. At 2 weeks (w), 4 w, 6 w and 8 w after infection, the body weight, survival rate, and bacteria count in the lungs of the mice were observed. Tumor necrosis factor-alpha (TNF-alpha), interleukin-12 (IL-12), IL-10, cluster of differentiation (CD)3(+)CD4(+) and CD3(+)CD8(+) cells were measured by flow cytometry. SLAM expression was detected by qPCR. Results: Compared with the normal saline control group, the body weight in the strain group was significantly decreased at 4 w and 8 w after infection, with statistical elevation of CD3(+)CD4(+) T lymphocytes and CD3(+)CD8(+) T lymphocytes at 2 w and 4 w (P<0.05). As time extended after 8 W, CD3(+)CD4(+) T lymphocytes began to decline whereas CD3+CD8+ T lymphocytes began to be increased. At 2 weeks after infection, the expression level of TNF-alpha, IL-12p40 in the lung M phi of mice in the strain group was markedly increased compared with that in the control group, (P<0.05). SLAM and IL-10 levels were rapidly increased at 2 w and 4 w, while they began to slightly decline at 6 w and 8 w (P<0.05). Conclusion: M.tb infection induces the increase of SLAM levels in the lungs of mice, while causing the alternation of TNF-alpha, IL-12, IL-10, CD3(+)CD4(+) and CD3(+)CD8(+) cells, which provided new insights for the diagnosis and evaluation of TB in clinical practice.