FIG 4.

Increased percentages of effector and memory IFN-γ-and IL-17-producing cells confer BCG-induced protection in C3Heb/FeJ mice. Shown are the percentages of pulmonary effector (CD44^hi CD62L^lo) and memory (CD44^hi CD62L^hi) cells obtained from control C3Heb/FeJ and C3H/HeOuJ mice as well as BCG-vaccinated immune C3Heb/FeJ and C3H/HeOuJ mice infected with a low-dose aerosol of M. tuberculosis W-Beijing strain SA161, analyzed by flow cytometry. During chronic infection, BCG-vaccinated C3Heb/FeJ mice expressed increased numbers of effector and memory cells capable of producing IFN-γ and IL-17, which was associated with bacterial clearance (D to F). In contrast, BCG-vaccinated C3H/HeOuJ mice showed reduced levels of IFN-γ- and IL-17-producing memory T cells during chronic infection. Results represent the average (n = 5) percentages of cells (±SEM). *, P < 0.050; **, P < 0.010; ***, P < 0.001 (determined by ANOVA and the Tukey posttest).