IL-7 therapy during the late contraction phase augments LCMV-specific T-cell responses. LCMV-Clone 13–infected mice were treated daily with either IL-7 or PBS between days 15 and 25 PI, as illustrated by the shaded area (A). At days 8, 26 (1 day after cessation of therapy), 45 (20 days after completion of IL-7 therapy), and 85 (60 days after IL-7 therapy) PI, CD8 and CD4 T-cell responses in the spleens of IL-7 (●)– or PBS (▴)–treated mice were quantified by flow cytometry. (B) The numbers of naive and activated CD8 or CD4 T cells. (C) LCMV epitope-specific CD8/CD4 T cells were quantified by intracellular staining for IFNγ. Data for each time point was obtained from 4-5 mice per group. *P ≤ .05; **P ≤ .005; ***P ≤ .001.