(A) Effect of purification on apoptosis. PBMCs were cultured for 48 h with endogenous electroeluted AaGroEL, E. coli rGroEL, electroeluted E. coli rGroEL, BSA and electroeluted BSA at 250 ng/mL. (B) Effect of LPS on apoptosis. Cells were cultured for 48 h with electroeluted, purified AaGroEL (AaGroEL) and LPS-removed AaGroEL (AaGroEL-ER) at 250 ng/mL. RPMI was used as a negative control, and camptothecin (CPT, 4 μM) was a positive control. Cultured cells were labeled with anti-CD3 antibody, Annexin V and 7AAD and analyzed by flow cytometry. Error bars represent the standard deviation, and * indicates p<0.05. The data are representative of 3 experiments with samples from different donors.