Activity of sIL-11R on Ba/F3 cell proliferation. Microwell assay with 200 cells added per well. Cells were visually counted and results expressed as a percentage of the maximal response (≥200 cells at 48 hours). (A) Ba/F3 cells expressing gp130 stimulated with sIL-11R alone (○) or combined with 500 pmol/L IL-11 (•). (B) Ba/F3 cells expressing gp130 and the transmembrane IL-11R stimulated with IL-11 alone (□) or combined with 40 nmol/L sIL-11R (▪). Control cultures stimulated with IL-3 alone (○) or combined with 40 nmol/L sIL-11R (•) are also shown.