Effect of Jak3 inhibitors on IL-5 and IL-13 production in MF2000 and SeAx tumor cells.

Treatment with Jak3 inhibitors inhibits IL-5 and IL-13 production in MF2000 and SeAx tumor cells. (A) Ag490 inhibits constitutive Stat3 activation. MF or SeAx cells were incubated for 16 hours in the indicated concentrations of Ag490. Cells were then lysed and analyzed by Western blotting with phosphotyrosine-Stat3 mAb (top) followed by reprobing with total Stat3 antibody (bottom). (B) Ag490 inhibits mRNA for IL-5 and IL-13. Cells were treated with Ag490 as mentioned above before RNA was isolated and analyzed by RNAse protection assay. L32 and GADPH are housekeeping genes. (C) Jak inhibitors inhibit cytokine production. Cells were treated with Ag490, Jak3-II (Jak inhibitors), or PP1 (src kinase inhibitor) for 16 hours. Cytokine production was then measured by ELISA.