Purified protein derivatives tuberculin from virulent or attenuated strains of Mycobacterium tuberculosis induces cell death of human macrophages in different manner / 中华传染病杂志

ABSTRACT

Objective To study the cell death in macrophages (THP-1) stimulated with different agonists (H37Rv-PPD or BCG-PPD) and to investigate the relationship between Toll like receptor (TLR)-2 and THP-1 apoptosis. Methods H37Rv-PPD and BCG-PPD were used to stimulate THP-1 cells for 3 h, 8 h, 15 h and 24 h, respectively with or without TLR-2 blockade. Cells were analyzed by flow cytometry to detect the TLR-2 expression. Annexin V staining and Hochest staining were performed to evaluate apoptosis. Results The apoptosis cells were increased when stimulated with BCG-PPD and the percentage was 30.2% at 24 h, which were confirmed by Hochest staining.However, the expression of TLR-2 did not increase simultaneously with percentage of 8.8% at 24 h.Nevertheless, most cells presented with necrosis form when stimulated with H37Rv-PPD and the expression of TLR-2 remained at high level with the percentage of 17.2% at 24 h, while the percent of apoptosis rate was only 7.7%. Under treatment of TLR-2 antibodies, the percentage of apoptosis decreased to 10.5% at 24 h of BCG-PPD stimulation and TLR-2 expressions were down-regulated to less than 3% at all time points; but after H37Rv-PPD stimulation, the percentage of apoptosis and TLR-2 expression did not changed obviously. Conclusions The attenuated BCG-PPD induces THP-1 apoptosis predominately, which is partially correlated with TLR-2 expression. While virulent H37Rv-PPD induces THP-1 necrosis predominately.