Toxoplasma gondii soluble antigen (STAg) induces resistance against Mycobacterium tuberculosis in a human monocyte cell line via P2X7 receptor.

BACKGROUND

The control of T. gondii in macrophages is mediated by the P2X7 receptor. The P2X7 receptor plays a crucial role in defense against Mycobacterium tuberculosis (M.tb), as well. Current study aimed to investigate the immunity induced by T. gondii soluble total antigen (STAg) against M.tb via P2X7R in human monocyte cell line.

METHODS

The STAg was prepared from 1.6 × 10 of fresh T. gondii tachyzoites, RH strain. The siRNA targeting P2X7R was employed to knockdown P2X7R in M0 THP-1 macrophages. Prior to M.tb infection, the cells were treated by 80 µg/mL of STAg for 4 h. The cells were infected by M.tb with multiplicity of infection (MOI) 5 for 3 h. The expression of the ATG5, ATG7, ATG16, P2X7R genes and the number of up taken M.tb were investigated by qReal-time PCR and absolute qReal-time PCR, respectively.

RESULTS

The qReal-time PCR analysis showed overexpression of the ATG5 gene in P2X7R siRNA, scramble siRNA, and STAg/siRNA and ATG7 in THP-1 cell line treated by STAg groups, while they were suppressed in STAg/siRNA/ M.tb and STAg/ M.tb groups. The expression of ATG16 was significantly overexpressed in STAg group, while it was suppressed in treated wells by STAg/siRNA, STAg/siRNA/M.tb, STAg/M.tb, and M.tb. The number of entered M.tb in STAg/M.tb was significantly lower than M.tb group. The number of M.tb in P2X7R-knockdown THP-1 cells was significantly higher than scramble siRNA and STAg. In addition, the number of the bacteria in STAg/siRNA was significantly lower than P2X7R siRNA group.

CONCLUSION

Our study showed that sensing macrophages by T. gondii STAg may induce levels of immunity against M.tb. In addition, our findings support available data, indicating potential role of P2X7R in macrophage against T. gondii and M.tb.