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.
ABSTRACT
Objective To study the different response in macrophages treated with different agoβ and IL-10 in Mycobacterium tuberculosisnists(H37Rv-PPD and BCG-PPD)related with Mycobacterium tuberculosis and the relationship with TNF-αt,IL-1β and IL-10.Methods Using H37Rv-PPD and BCG-PPD to stimulate THP-1 cell for 3h,8h,15h,24h respectively.Cells were ananlyzed by Hochest staining under fluorescence microscopy to assay cell death(apoptosis and necrosis).At each stimulating time,TNF-α,IL-1β and IL-10 were examined by ELISA.Results Under fluorescence microscopy,it could easily see oval apoptotic bodies of THP-1 stimulated by BCG-PPD.However ,the nucleus were often isolated and necrosis-like when cells were stimulated by H37Rv-PPD.In a word ,BCG-PPD tend to induce THP-1 cells to apoptosis,but H37Rv-PPD inclined to induce cells to undergo necrosis.In supernatant of cells stimulated by BCG-PPD,the expression of TNF-αand IL-10 were lower than the cells stimulated by H37Rv-PPD,but the expression of IL-1β was higher than the latter.Conclusion It indicated that the necrosis of cells stimulated by H37Rv-PPD was asossiated with the excessive expression of TNF-α and IL-10,and the apoptosis of cells induced by BCG-PPD was IL-1β related.Perhaps the mechanism of differences in virulence exist in protein of strain,and associated with cytokines IL-1β,TNF-α and IL-10.