Complexed soluble IL-7 receptor α and IL-7 increase IL-7-mediated proliferation and viability of CD8⁺ T-cells in vitro.

Many soluble cytokine receptors inhibit cytokine bioactivity, while others prolong ligand activity. The biological role of an endogenous soluble form of IL-7Rα, or its therapeutic effects on CD8(+) T-cells are unknown. We demonstrate that recombinant IL-7Rα-Fc, when pre-incubated with IL-7, enhances IL-7-induced CD8(+) T-cell proliferation and viability of human or murine CD8(+) T-cells. Receptor blocking experiments confirmed IL-7-specific activity. These data demonstrate that exogenous soluble IL-7Rα significantly enhances CD8(+) T-cell responses to IL-7 in vitro and paves the way for future research to determine its therapeutic potential to restore impaired CD8(+) T-cell function in disease.