Approximately1–2% of the transferred P25TCRTh1 cells were stimulated to produceIFN-γ in vivo at that time point (Figure 2C), and this percentage was similarto the frequency of total endogenous lung CD4+ T cellsexpressing IFN-γ on day 21 post-infection (Figure 1B, 2D). The gene discussed is IFNG; the disease is infection.