Figure 1.
Strategies to dissect inhibitory mechanisms of PD-1. (A) Fc chimera and PD-1 constructs. The cytoplasmic regions of PD-1, its mutants, and KIR were fused with the extracellular region of FcγRIIB. A flag tag was added to each Fc chimera. (B) Cell surface expression of Fc chimeras and PD-1. Sorted Fc chimera and PD-1 transformants were stained with anti-FcγRIIB and anti-PD-1 mAb, respectively. GFP, green fluorescence protein. (C) Schematic representation of stimulation strategy. Incubation with intact anti-mouse IgG Ab results in coligation of Fc chimera and BCR (Right), whereas a F(ab′)2 fragment of anti-mouse IgG Ab results in BCR-only ligation (Left).