Figure 4

Activation of memory-type CD4 ⁺ T cells by BCG-dHCM through activation of macrophages. a. IFN-γ production from memory type CD4⁺ T cells by stimulation with BCG-dHCM. Macrophages differentiated by using M-CSF were infected with either BCG-261H or BCG-dHCM at the indicated MOI, and were used as a stimulator of responder CD4⁺ T cells in a 4-day culture. 10⁵ responder T cells were stimulated with the rBCG-infected macrophages at T: macrophage = 10: 1. b. Inhibition of T cell activation by the treatment of BCG-dHCM-infected macrophages with mAb. Macrophages were infected with BCG-dHCM at the indicated MOI, and subsequently treated with 10 μg/ml of the mAb or normal murine IgG. These APCs were used as the stimulator of the indicated responder T cells (1 × 10⁵/well) at the indicated T/macrophages ratios for 4 days. IFN-γ produced by T cells was measured. c. Effect of chloroquine treatment of macrophages on the activation of T cells. Macrophages were treated with chloroquine (50 μM, 2 h) or untreated, and subsequently infected with BCG-dHCM at the indicated MOI. These macrophages were used as the stimulator of the indicated responder T cells at the indicated responder/stimulator ratios. IFN-γ produced by T cells was measured. A representative of three separate experiments conducted by using 3 different PBMCs-donors is shown. Assays were performed in triplicate and the results are expressed as the mean ± SD. Titers were statistically compared using Student’s t-test.