Characterization of IL-4 receptor by affinity cross-linking
Cells (4 × 106) were incubated with 125I-IL-4 in the absence (lane 1) and presence of either unlabeled IL-4 (lane 2) or IL-13 (lane 3) for 2 hr at 4°C (A) as described in Materials and Methods. (B) IL-4/IL-4R complex was immunoprecipitated with anti-hIL-4R antibody, P7 (lane 1) or anti-γc antibody (lane 2) overnight at 4°C. The cell lysates were electrophoresed on 8% SDS-PAGE gel and autoradiographed. The arrows on the left indicate the specific IL-4R bands. Lane 1 (A) is from the same gel and has been realigned for presentation.