Extended Data Fig. 2: Development of domain-specific PD-L1 antibodies.
From: PD-L1 expression by dendritic cells is a key regulator of T-cell immunity in cancer
a-b, To assess PD-L1 blocking activity, an ELISA-based assay was used to test the ability of anti-PD-L1 antibodies to impair PD-L1 binding to either PD-1 or B7-1 as purified proteins. a, Anti-PD-L1 clones 6E11 and 27C11 blocked the binding of PD-L1 to PD-1 (IC50 = 0.31 nM and 1.85 nM, respectively), whereas clone 17H9 was inactive. b, Anti-PD-L1 clones 17H9 and 6E11 blocked the PD-L1 and B7-1 interaction in a dose-dependent manner (IC50 = 0.085 nM and 0.42 nM, respectively), whereas clone 27C11 had a negligible effect (IC50 > 100 nM). a-b, Data are representative of two independent experiments. c, Addition of anti-PD-L1 clones 6E11 and 27C11 to cultures of Jurkat cells expressing chimeric PD-1 and human CD3ζ receptors (Jurkat-PD1-CD3) and PD-L1-expressing K562 cells inhibits NFAT-dependent luciferase reporter signaling in a dose-dependent manner, whereas clone 17H9 has minimal effect. Data are representative of two independent experiments. d, Addition of anti-PD-L1 clones 17H9 and 6E11 to cultures of Jurkat cells expressing chimeric PD-1 and human CD3ζ receptors (Jurkat-PD1-CD3) and B7-1-expressing K562 cells inhibits NFAT-dependent luciferase reporter, whereas clone 27C11 has no effect. Data are from a single experiment. Circles represent individual technical replicates and bars represent mean values. e, TR-FRET analysis of cells co-expressing SNAP-tagged B7-1 and ACP-tagged PD-L1 in the presence or absence of the 17H9 anti-PD-L1 antibody. Data are representative of two independent experiments, each performed in triplicates.
