Fig. 6.

Effector/effector memory T cells from human T cells undergoing IL-2 therapy express upregulated PD-1. PBMCs were isolated prior to therapy and on day 8 of treatment from patients undergoing high dose systemic IL-2 therapy for melanoma. PBMCs were assessed for T cell subset expression of PD-1 by flow cytometry. a Representative gating strategy for staining of human PBMCs. b-c Frequency of PD-1 expression on memory CD4 (b) and CD8 (c) T cells. (d-e) Frequency of PD-1 expression on central (CD45RO + CD62L+) and effector memory (CD45RO + CD62L-) subsets in CD4 (d) and CD8 (e) T cells. Six patient samples were included in this data set. Data are presented as mean ± SEM. Statistics were derived using Student’s T test, *P < 0.05, **P < 0.01, ***P < 0.001