Characterization and Comparison of the Interleukin 13 Receptor with the Interleukin 4 Receptor on Several Cell Types

Abstract

We describe here the characterization of the interleukin (IL) 13 receptor and a comparison with the IL-4 receptor on different cell types. Several, but not all, of the IL-4 receptor-positive cells showed specific IL-13 binding, which was always completely displaced by IL-4. In the IL-13 receptor-positive cells, the IL-13 either completely or partially displaced the labeled IL-4. Further characterization of the IL-13 receptor in two cell lines, COS-3 and A431, representative of the groups of complete and partial displacement of IL-4 by IL-13, respectively, showed that the IL-13 binds with high affinity (Kd approximately 300 pM) to both cells and that the number of binding sites is, in COS-3 cells, equivalent to that for IL-4 and, in A431 cells, is smaller than that for IL-4. Cross-linking of labeled IL-13 yielded, on COS-3 cells, two affinity-labeled complexes of 220 and 70 kDa, and on A431 cells, one complex of 70 kDa; labeled IL-4 yielded on both cells the same pattern of three complexes of 220, 145, and 70 kDa. Altogether, these results suggest that the IL-13 receptor may be constituted by a subset of the IL-4 receptor complex associated with at least one additional protein.

Cloning of the human IL‐13Rα1 chain and reconstitution with the IL‐4Rα of a functional IL‐4/IL‐13 receptor complex

“…The high affinity binding site was not detected if the saturation experiments were performed in the presence of a large excess of IL-4 (not shown). No modification in IL-13 affinity resulted from the co-expression of IL-13Rotl and IL-13Roc2 (not shown) and IL-13 did not bind to IL-4Ra, as previously described [5].…”

“…Binding experiments on transfected CHO cells were performed using radiolabelled hIL-13 as described [5].…”

“…The IL-4 receptor comprises two chains, the IL-4Ra and the yc [7][8][9][10]. Neither of these two chains binds IL-13 [5], but recent reports have shown that IL-4Ra contributes to the IL-13 receptor [11][12][13].…”

“…The functional redundancy of IL-4 and IL-13 suggested very early on that both cytokines probably shared receptor components [4][5][6]. The IL-4 receptor comprises two chains, the IL-4Ra and the yc [7][8][9][10].…”

Induction of the IL-13 receptor α2-chain by IL-4 and IL-13 in human keratinocytes: involvement of STAT6, ERK and p38 MAPK pathways

“…Indeed, the binding of IL-13 to the latter receptor has been previously shown to be readily displaced by either IL-4 or IL-13. In addition, the radiolabeling of native IL-13, used in this study, results in the production of a reagent that appears to only bind to the IL-13Ra2, in contrast to the modi®ed form of IL-13, 125 I-IL-13-GYGY, which binds both IL-13Ra1 and IL-13Ra2 (see Materials and methods) (Vita et al, 1995). These results suggest that the 125 I-IL-13 binding protein detected in response to IL-4 was IL-13Ra2 and not IL-13Ra1.…”