FIG. 6.

Ag85B pDNA vaccine protects reconstituted CD4^−/− mice against an intratracheal challenge infection. (A) All mice received four doses of Ag85B DNA (100 μg/dose, i.m.) at 3-week intervals. Six weeks later, adoptively transferred (20 × 10⁶ CD4⁺ T cells) CD4^−/− mice that received the control pDNA or Ag85B pDNA, as well as naïve CD4^−/− mice, were given an intratracheal challenge with luminescent M. tuberculosis (10⁴ CFU/mouse = 15 RLU) in parallel with WT vaccinated mice. (B) B6 CD4^−/− (ko) mice before and after reconstitution with 20 × 10⁶ CD4⁺ T cells were vaccinated with BCG (intravenously) and, 8 weeks later, infected intratracheally with luminescent M. tuberculosis, as described above. Four weeks later, mice were sacrificed and the load of bacilli in lungs and spleen was measured on a luminometer as RLU. *, P < 0.05 compared to naïve CD4^−/− mice or naïve WT mice; **, P < 0.001 compared to naïve CD4^−/− mice.