Immunoblot Analysis Jurkat cells were c ultured under serum-free conditions for 48h and subsequently were either unstim ulated (lane 1) or stim ulated with 300mM sorbit (lane 2), 1mM arsenite (lane 3) or 1mM pervanadate (lane 4).The cell lysates were separated by SDS-PAGE and transferred to a PVDF membrane. The immunoblot was probed with mab SAPK1/2-9H8 at 0.5 ug/ml for 1h at 15-22°C and developed by ECL.