Adjuvant IL-7 potentiates the efficacy of adoptive CD4+ T-cell transfer by augmenting the expansion and persistence of polyfunctional CD4+ effector cells. Following the timeline depicted in the schema, mice with established systemic A20HA tumors were randomly grouped and received either no treatment (no Tx) or HA-specific CD4+ T-cell transfer (CD4) under one of the following conditions: CD4+ T-cell transfer only (CD4), CD4+ T-cell transfer and rhIL-7 administration (CD4+ rhIL-7), CTX pre-conditioning and CD4+ T-cell transfer (CTX + CD4), CTX pre-conditioning and CD4+ T-cell transfer plus rhIL-7 administration (CTX + CD4+ rhIL-7). (A) Administration of rhIL-7 enhances the expansion and duration of the donor CD4+ T cells in CTX-conditioned mice. Tail blood collected at the indicated time points were analyzed for donor T cell frequencies by FACS. Results shown are representative of two independent experiments with 5 mice in each group. *P < 0.05. **P < 0.01. (B) rhIL-7 administration sustains the polyfunctionality of the donor CD4+ T cells. Tail blood was collected at the indicated time points and subjected to cytokine ICS analysis. Plots shown are gated on TNFα+ divided donor CD4+ T cells. The numbers represent the percentage of cells co-expressing TNFα, IL-2 and IFNγ. Results shown are representative of two independent experiments. (C) rhIL-7 administration potentiates the efficacy of CD4+ T-cell transfer in CTX-conditioned mice. The Kaplan-Meier plot depicts the overall survival of mice under each treatment condition. Results shown are pooled data from 3 independent experiments.