Soluble CD127 potentiates IL‐7 activity in vivo in healthy mice

INTRODUCTION: Soluble forms of cytokine receptors can be involved in the endogenous regulation of cytokine activity. Soluble interleukin 7 receptor α (sCD127) naturally binds IL‐7, therefore there is interest in its potential application as an immunotherapeutic agent to regulate IL‐7. With the hypothesis that sCD127 enhances IL‐7 activity, thus promoting T‐cell proliferation in vivo, we sought to assess the effect of sCD127, IL‐7 or IL‐7 + sCD127 treatment on CD4(+) and CD8(+) T‐cells in the blood and spleen of mice. METHODS: Peripheral blood mononuclear cells and splenocytes were prepared, and analyzed for T‐cell number, phenotype and proliferation (Ki67(+)) by flow cytometry. RESULTS: IL‐7 treatment induced T‐cell proliferation, increased T‐cell number, and triggered T‐cell differentiation each of which was enhanced with the addition of sCD127. IL‐7 + sCD127 treatment significantly increased spleen weight over that seen with IL‐7 treatment alone. More pronounced proliferation and a greater increase in cell number was observed in CD8(+) T‐cells relative to the effect on CD4(+) T‐cells. CONCLUSIONS: These findings suggest that the addition of sCD127 enhances IL‐7‐mediated T‐cell proliferation and suggests a potential therapeutic use for sCD127.