Human rIL-2 has a differential, dose-dependent effect on CD4+ and CD8+ T cell subsets . (A) Gating strategy to identify naive (N), central memory (CM), effector memory (EM) and terminal differenciated (TD) T lymphocytes. Cells were first gated on side and forward scatter parameters (gate R1) and further gated on CD4+ (or CD8+) T cells (gate R2). Thereafter, CD4+ (or CD8+) T cell subsets were analyzed for the expression of CD45RA and CD62L molecules. CD45RA+CD62L+ were identified as naive, CD45RA-CD62L+ as central memory (CM), CD45RA-CD62L- as effector memory (EM) and CD45RA+CD62L- as terminal differentiated (TD) T cells. (B) Percentages and counts of each CD4+ T cell subpopulation were followed in IL-2-treated animals - low dose (ОΔ) or high dose (●▴) (C) Similarly, percentages and counts of each CD8+ T cell subpopulation were followed in IL-2-treated animals - low dose (ОΔ) or high dose (●▴).