Fig. 4.

L-MDSC suppression through PD-1/PD-L1 is modulated by GM-CSF. a Flow cytometry was used to determine PD-1 expression on fresh CAR-T (CAR-T gated as CD3+Wi2+ cells) relative to FMO controls. b Flow cytometry was used to determine PD-L1 expression on L-MDSC (gated CD11c−CD11b+Gr-1+) isolated from tumor-bearing mice after 2 weeks of tumor growth relative to FMO controls. c Representative dot plots indicating PD-L1 expression as determined from BM-derived MDSC (gated as live, CD45+CD11c−CD11b+Gr-1+ cells) following exposure to recombinant GM-CSF or GM-CSF-producing tumor ex vivo. d Pooled results from two independent experiments are graphed. Bar graphs represent mean ± SEM; dot plots and histograms are representative of ≥3 mice per group and have been confirmed with ≥2 separate experiments (*p ≤ 0.05)