Ligand-induced autoregulation of IL-2 receptor α chain expression in murine T cell lines

Open Access
Publisher Website
Google Scholar
Abstract
The IL-2 receptor (IL-2R) is composed of three chains a, β and γ. In mice, contrary to the human system, we have previously demonstrated that the IL-2Rβγ complex does not bind IL-2. Therefore, mouse IL-2 response is completely dependent on the expression of the IL-2Rα gene product. T cell clones expressing mouse IL-2Rβγ and the human IL-2Rα transgene have been studied. When cells are grown in IL-4, mouse IL-2Rα is not expressed. However, exposure to IL-2 leads to the expression of the endogenous murine IL-2Rα subunit. The T cell line expressing mouse IL-2Rγ and human IL-2Rβ can grow in IL-2 but does not express endogenous murine IL-2 Rα. Transfection of these cells with the human IL-2Rα gene restores the capacity to induce murine IL-2Rα. This result demonstrates that IL-2-IL-2Rα interactions are required for induction of IL-2Rα. The kinetics of induction and deinduction of murine IL-2Rα have been studied using clone 18.III. From negative cells, expression of murine IL-2Rα is a very slow phenomenon. From cells fully expressing IL-2Rα, deinduction is a two-step process: after a rapid decrease of IL-2Rα the cells continue to express, for a long period of time, basal levels of murine IL-2Rα. When cells expressing basal levels of IL-2Rα are exposed to IL-2, induction of IL-2Rα is a very rapid phenomenon. The autoregulatory loop formed by IL-2-IL-2Rα therefore displays different levels of functioning.

This publication has 0 references indexed in Scilit: