Effect of ESAT-6 and CFP10 on the viability and apoptosis of T cells. CD3+ cells from three healthy donors were cultured with medium alone, ESAT-6, or CFP10 for 1 h, then stimulated with anti-CD3 and anti-CD28. After 48 h, cell viability was analyzed by trypan blue exclusion (A) and MTT assay (B). C, Apoptosis was analyzed by annexin V staining, followed by flow cytometry analysis. In A, the number of viable cells in the wells treated with medium alone was arbitrarily given a value of 1.0. Mean values and SD are shown.