Profound Functional Suppression of Tumor-Infiltrating T-Cells in Ovarian Cancer Patients Can Be Reversed Using PD-1-Blocking Antibodies or DARPin® Proteins
PD-1 expression and effector function capacity of T-cells isolated from healthy controls (HC) and epithelial ovarian cancer (EOC) patients. (a) Proportion of PD-1+ (%) CD4+ and CD8+ T-cells isolated from the peripheral blood of HC () and the blood (), ascites (), and tumor () of EOC patients. Gating strategy included singlets, followed by viable cells (being 7AAD-), lymphocyte gate (by forward/side scatter), and T-cells (CD3+), followed by expression of CD4+ and CD8+ and lastly by expression of PD-1 on these subsets. (b) Representative histograms of PD-1 expression on CD4+ and CD8+ T-cells from one patient. Cells from the tumor were used for the isotype control. (c) Absolute concentrations of IFN-γ (normalized to reflect per 500,000 T-cells) after stimulation with α-CD3 (OKT-3) for 48 h. (d) The median release of IFN-γ in HC after stimulation with α-CD3 was set to 100% and defined full response (effector function capacity). The release measured in the samples from EOC patient blood, ascites, and tumor was compared to the release observed in HC blood samples. Median values with interquartile ranges are presented. IFN-γ was measured using ELISA, and the data was normalized to reflect the same cell number (per 500,000 T-cells). Unpaired Mann-Whitney was performed as statistical analysis. Significance levels were set to ,, and .
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