Recombinant sγc inhibits cytokine-induced proliferation in a dose-dependent and specific manner.

Cells were preincubated with serial dilutions of concentrated supernatants of 293/EBNA cells, expressing 255N-Stop-sγc (black bars) or the equally treated supernatants of vector-transfected cells (control, open bars) 30 minutes before the addition of cytokines. (A) L1/1 T cells were stimulated using IL-2 (2 ng/mL). (B) MC-9 mast cells were stimulated using IL-4 (1 ng/mL), (C) IL-9(1 ng/mL), or (D) IL-3 (1.25% IL-3-BPV-SN). After 48 hours, [³H]thymidine was added, and 16 hours later, cells were harvested and radioactivity was measured in a β-counter. The data presented are representative of at least 5 comparable assays per cytokine tested. Bars marked with w/o represent cytokine proliferation in the absence of inhibitor (100% control value).