After activating Jurkat cells with PMA (25 ng/mL) and ionomycin (1 µM), I observe that the cells either begin to die or significantly reduce their proliferation. I seeded the cells in a 24-well plate at varying densities (1.25 × 10^5 to 5 × 10^5 cells/ml) using RPMI medium supplemented with 10% FBS and penicillin/streptomycin. Following seeding, I added the activators and incubated the cells at 37°C for 6, 24, and 48 hours. For the control groups, I used either DMSO (as the activators are dissolved in it) or an equivalent volume of RPMI medium.

Within the first six hours of activation, I noticed a drop in cell concentration in the samples treated with PMA and ionomycin. Subsequently, the treated cells proliferate more slowly compared to both control groups (DMSO or RPMI alone).

Does anyone have insights into why this might be happening?