IL-13 receptor α 2: A regulator of IL-13 and IL-4 signal transduction in primary human fibroblasts

Background IL-13 and IL-4 share many functional properties as a result of their use of a common receptor complex comprising IL-13 receptor α 1 (IL-13Rα1) and IL-4 receptor α (IL-4Rα). The nonsignaling receptor IL-13 receptor α 2 (IL-13Rα2) binds IL-13 with high affinity and specificity and is believed to be a decoy receptor for IL-13. Objective We sought to examine the inhibitory effects of soluble and membrane-bound IL-13Rα2 on IL-13– and IL-4–mediated effects. Methods Primary human fibroblasts were grown from endobronchial biopsy specimens obtained from volunteers. Upregulation of IL-13Rα2 mRNA was measured by means of RT-PCR, and the level of surface expression was measured by means of F…