CD4 T cells specific for M avium can drive immune reconstitution disease. (A) M avium–infected TCRα^−/− mice received CD4 T cells (2 × 10⁶ each) isolated from uninfected WT or OT-II mice. The shaded area between the traveling error bars represents the SD. (B) Uninfected or M avium–infected TCRα^−/− mice received P25 (Ag85b specific TCR Tg) CD4 T cells (2 × 10⁶) or no T cells, and survival was monitored. (C) Bacterial loads in the lungs of infected mice from panel B 7 days after transfer of P25 CD4 T cells. (D) Total nitrate and (E) TNFα were measured in the serum of mice from panel B on day 5 of P25 transfer. (F) CD11b⁺ cells were measured in the blood and (G) lung of mice from panel B on day 5 of P25 transfer. (H) Phenotype of CD11b⁺ cells in the PBMC of M avium–infected TCRα^−/− mice on day 6 of P25 transfer.