Inhibitory effect of MPT64 antigen from Mycobacterium, tuberculosis against apoptosis of macrophages / 第二军医大学学报

ABSTRACT

Objective To explore the effect of MPT64 antigen from Mycobacterium tuberculosis on RAW264. 7 macrophages and the related mechanism. Methods MPT64 was purified after expression in E. crSi and verified by Western blotting analysis. The RAW264. 7 differentiation was induced by phorbol myristate acetate (PMA) and the resultant cells were divided into three groups according to different treatments negative control, purified protein derivative of BCG(BCG-PPD) and BCG-PPD+MPT64 treatment groups. After 16 h incubation, flow cytometry was used to examine apoptosis of macrophages, and the levels of TNF-α and IL-10 in the supernatants were determined by ELISA. Results BCG-PPD treatment induced apoptosis of RAW264. 7 macrophages, and compared with BCG-PPD group, the apoptotic level of macrophages was significantly lower in BCG-PPD+MPT64 group (P<0. 05). We also found that the supernatant TNF-a level in the BCG-PPD group was significantly higher than that in negative group (P<0. 01) and the IL-10 levels were not significantly defferent between the two groups. Compared with BCG-PPD group, the IL-10 levll was significantly increased in BCG-PPD + MPT64 group (P<0. 01) and the TNF-a levels were not significantly different between the two groups. Conclusion MPT64 may act as a virulence factor and can inhibit the apoptosis of macrophages induced by BCG-PPD, which is probably through increasing IL-10 level.