Comparison of STAT1-pTyr and STAT2-pTyr phosphorylation downregulation in sensitive (D_W^S) and resistant (D_W^R) Daudi cells during tyrosine kinase inhibition. STSP (250 nmol/L) was added at 2 hours after cell treatment with 100 U/mL of IFN-α. Effects on STAT1-pTyr and STAT2-pTyr at 30-minute intervals were disclosed by IP, gel electrophoresis, and 4G10 Western blots developed with ECL. Total latent and phosphorylated STATs were assessed by reprobing of the transfer membranes with specific anti-STAT antibodies and secondary detection by phosphatase substrate reaction.