Annexin V staining

Effector cells (729.6 HTLV-1_WT or 729.6 HTLV-1_p12KO) were lethally irradiated (20 min for a dosage of 12 grays, Precision X-Ray, 320KV X-rays). Before 24, 48, and 72 h post-irradiation cells were stained with Annexin V, Alexa Fluor 647 conjugate (ThermoFisher Scientific). Briefly, cells were washed with PBS and 0.5x10⁶ cells were suspended in 1X Annexin V binding buffer (ThermoFisher Scientific). Alexa Fluor 647 conjugate (5 drops) was added to the cells and incubated at room temperature for 15 min in the dark. Cells were then washed with 2 ml of 1X Annexin V binding buffer. Cells were then collected and samples analyzed by flow cytometry (BD LSR II). Data were analyzed using FlowJo Version 10.6.