Fig. 6.

Gating scheme for yeast/mammalian cell binding analysis. CellTrace^™ Violet-labeled PD-L1-expressing Chinese hamster ovary (CHO)-K1 cells were incubated with either yeast expressing an anti-programmed cell death protein 1 (PD-1) scFv (Control Yeast) or yeast expressing an anti-PD-L1 scFv (Specific Yeast). Fluorophore-conjugated anti-cmyc antibody was used for detection of scFv-expressing yeast cells. The left panel depicts the gating scheme for mammalian cells from all events (CellTrace^™ Violet histogram). The middle and right panels consist of the mammalian cell population, wherein a yeast-unbound (left peak) and a yeast-bound (right peak) population exist. Distinct profiles are observed for anti-PD-1 scFv-expressing (Control) versus anti-PD-L1 scFv-expressing (Specific) yeast binding to PD-L1-expressing CHO-K1 cells, demonstrating specific binding