Expression of IL-23R and activity of IL-23 in B-ALL cell lines. (A) IL-23R surface expression in human B-ALL cell lines as assessed by flow cytometry. Open profile: IL-23R staining; dark profile: isotype-matched mAb staining. (B-C) Analysis of STAT pathway in 697 cells stimulated 30 minutes with IL-23 or of IFN-α (positive control), as assessed by Western blot (B) and flow cytometry (C). (D) Flow cytometric analysis of cell cycle in 697 cells cultured 48 hours with or without IL-23. Unbroken profile: 697 cells cultured with medium alone; dashed profile: 697 cells cultured in the presence of IL-23.