Figure 3.

BCG-specific T cells cross-protect against MAV and MAB. Total PBMC or subsets of T cells purified after 7 days of optimal BCG stimulation were co-cultured with autologous macrophages infected with MAV or MAB (E:T of 10). Residual mycobacteria quantified 3 days after co-culture and percent inhibition calculated by dividing the number of residual mycobacteria in the presence BCG-stimulated PBMC by the number of residual mycobacteria in control cultures containing medium-rested PBMC. (A) BCG-expanded T cells inhibit intracellular MAV (n = 8) and MAB (n = 5) as potently as they inhibit intracellular BCG (n = 8). BCG-expanded T cells inhibited intracellular MAV better than intracellular BCG (**p < 0.01, Mann-Whitney U test). (B) Pure CD4, CD8, and γδ T cells inhibited intracellular MAV, and the level of inhibition was similar to inhibition by total BCG-expanded PBMC. (C) Pure CD4, CD8, and γδ T cells inhibited intracellular MAB, and the level of inhibition is similar to the levels of inhibition mediated by total BCG-expanded PBMC.