FIG. 1.

M. tuberculosis-induced apoptosis in PMN depends on M. tuberculosis/PMN ratio. N-PMN (▴) and TB-PMN (▪) (3 × 10⁶/ml) were cultured in medium alone (control) or stimulated with M. tuberculosis (Mtb) at different M. tuberculosis/PMN ratios (1:3, 1:1, 10:1, and 20:1) for 18 h. Thereafter, apoptosis was evaluated on the basis of AV-FITC binding. Results are expressed as means (± standard errors of the means) of the percentage of AV⁺ cells (n = 10). Statistical differences for control versus M. tuberculosis: *, P < 0.0001; ϕ, P < 0.0005; #, P < 0.01. Statistical differences for N-PMN versus TB-PMN: Ψ, P < 0.02, Φ, P < 0.005.