Figure 6.

In vitro PD-1 blockade leads to enhanced proliferation of T cells, but affects most strongly the clonal tumor T cells in blood from SS patients.

In vitro treatment with nivolumab 10 µg/mL and subsequent detection of cell proliferation upon stimulation with PMA/ionomycin in total CD4⁺ T cells (a), non-clonal bystander T cells (b), clonal tumor T cells (c) or CD8⁺ T cells (d). Cell proliferation was assessed by flow cytometry via measurement of the incorporation of non-radioactive 5-bromo-2ʹ-deoxyuridine (BrdU) in newly synthesized DNA. (e-f) Representative histograms depicting how PD-1 blocked affects BrdU incorporation in the different T cell fractions, as described in (a-d). Data are from five individual SS patients. Abbreviations: ns: P > .05; *: P ≤ 0.05; **: P ≤ 0.01