Human rIL-2 modulates spontaneous CD4+ and CD8+ T cell apoptosis . Apoptotic cell death was assessed using FITC-conjugated AnnexinV. Total CD4+ (A) and CD8+ (C) T cell apoptosis was measured after 16 h of culture at day 0, 7 and 45 after IL-2 treatment. In order to assess the propensity of each subset to undergo apoptosis, apoptosis was then measured in each CD4+ (B) or CD8+ (D) T cell subpopulation (N, CM, EM or TD) at day 0 and day 7 after IL-2 treatment. T cells, gated on lymphocytes gate followed by gating on CD4+ or CD8+ Tcells, were analysed for CD45RA and CD62L expression. Each subpopulation (N, CM, EM and TD) was then assessed for AnnexinV expression and sensitivity was calculated as follows for each subset:% AnnexinV+among subset = N (CM, EM or TD) AnnexinV+T cells/ (N (CM, EM or TD) AnnexinV+T cells + N (CM, EM or TD) AnnexinV-T cells) x100.