The γ subunit of the interleukin-2 receptor is expressed in human monocytes and modulated by interleukin-2, interferon γ, and transforming growth factor β1

Abstract

The interleukin-2 receptor γ (IL-2Rγ) chain is a newly recognized component of the IL-2R of lymphoid cells that is required for their response to IL-2. We investigated the expression of IL-2Rγ protein in human monocytes by Western blot analysis using an antiserum specific for IL-2Rγ. We found that IL-2Rγ subunit is constitutively expressed in human monocytes and upregulated by the monocyte-activating factors IL-2 and interferon γ (IFNγ). Furthermore, we show that transforming growth factor β1 (TGFβ1) downmodulates, in a dose-dependent manner, basal and IL-2-induced, but not IFNγ-induced, IL-2Rγ chain expression, and this effect may be responsible for TGFβ1 suppressive activity on IL-2-activated monocytes. Overall, these results show that the expression of the IL-2Rγ subunit in human monocytes is tightly regulated by the cytokine network, suggesting a critical role played by this protein on monocyte activation.