Sandwich ELISA - IFN gamma Human ELISA Kit (ab46025)Jurkat were stimulated for 48 hours with 50 ng x mL-1 of PMA (ab120297) and 1 uM Ionomycin (ab120116) and PBMCs were stimulated for 48 hours with 2 % PHA-M (LifeTechnologies). Cell free supernatants were tested, showing results after background signal was subtracted (duplicates +/- SD).