Figure 4.

M. tuberculosis components induced NO production from A549 cells infected with M. tuberculosis followed by stimulation with a cytokine mix along with different mycobacterial components. For estimation of NO, cell culture supernatants were harvested at 24, 48, 72 and 100 hr following stimulation. Results were the mean ± SEM of three independent experiments (n = 3). When paired t-tests were performed between A549 cells alone and infected A549 cells stimulated with the cytokine mixture and mycobacterial components, the P-value was <0·001 in the case of all components. Paired t-tests were also performed between infected A549 cells stimulated with cytokine mixture only and infected A549 cells simultaneously treated with the cytokine mixture and different antigenic components. The P-value (ϕ) was < 0·05 in experiments using WCL and CW only. WCL, whole cell lysate of H37Rv; CW, cell wall of H37Rv; MEM, membrane fraction of H37Rv; CYT, cytosol fraction of H37Rv; LAM, lipoarabinomannan of H37Rv. (Infection with H37Rv and cytokine stimulation was common in all experiments shown here as a bar diagram.)