Production of T cells responsive to the secondary stimulation in mice by infection with BCG-dHCM. Three 5-week-old C57BL/6 mice per group were each infected with 1 × 103 CFU of either BCG-261H or BCG-dHCM subcutaneously. Four (a) or 12 (b) weeks after the inoculation, splenocytes (2 × 105 cells/well) were stimulated with the indicated stimulators for 4 days in vitro, and IFN-γ produced in the cell supernatant was measured. Assays were performed in triplicate for each mouse, and the results of three mice per group are shown as the mean ± SD. Representative results of three separate experiments are shown. Titers were statistically compared using Student’s t-test.