IL-7 treatment of SIV-infected macaques (100 μg/kg/d) leads to increased levels of circulating IL-7, increased CD4⁺ and CD8⁺ peripheral blood T-cell numbers, and down-regulation of IL-7Rα.

(A) Plasma levels of IL-7 detected using enzyme-linked immunosorbent assay (ELISA). Lines represent individual animals. (B) Absolute numbers of CD4⁺ T cells following vaccination with (solid lines) and without (dotted lines) IL-7 treatment. (C) Absolute numbers of CD3⁺/CD8⁺ T cells following vaccination with (solid lines) and without (dotted lines) IL-7 treatment. The increase by day 10 was significant for both CD4⁺ and CD8⁺ T cells (P < .05, Wilcoxon signed-rank test). (D-E) IL-7 therapy decreases IL-7Rα expression on circulating CD4⁺ and CD8⁺ T cells.