Effect of kinase inhibitors on the growth activity of IL-5 and SCF in JYTF-1 cells.

(A) Differential growth properties to inhibitors in cells cultured in IL-5 and SCF. JYTF-1 cells were seeded into media containing IL-5 or SCF with or without PD98059 (100 μmol/L) or LY294002 (40 μmol/L). After 24 and 48 hours of incubation, viable cell numbers were measured in each sample and the values are presented as the percentage of starting cell number in each culture condition. Each number represents the average of 3 independent experiments performed in duplication. Free (■), IL-5 (⋄), IL-5 plus 100PD (○), IL-5 plus 40LY (▵), SCF (♦), SCF plus 100PD (●), SCF plus 40LY (▴). (B) Differential effect on antiapoptotic activity in IL-5– and SCF-cultured cells. JYTF-1 cells were treated as described in panel A and the extent of nucleosome released from apoptotic cells was measured after 24 hours of incubation. Each value is the average of 3 independent quadruplet experiments, and the SEs are shown as error bars.