Figure 5.

Human anti-CCR8 mAb GS-1811 binds specifically to human CCR8 and antagonizes its activity.

a) Specific binding of GS-1811 to CHO-S cells expressing hCCR8, hCCR4 or to control parental cell line as determined by flow cytometry. Each data point represents average of three replicates ± SD. b) Antagonistic activity of GS-1811 in the presence of human CCL-1, evaluated by the PathHunter eXpress human CCR8 CHO-K1 ßArrestin GPCR Assay. Each data point represents average of three replicates ± SD. c) Summary of GS-1811 on-cell affinity as measured by MSD assay. Mean dissociation constant (KD) and standard deviation (SD) were calculated from 3 independent experiments. d) Flow cytometry analysis showing GS-1811 binding to different T cell populations from healthy PBMCs or human primary colon tumor samples; left: representative histograms; right: percentage of CCR8+ cells in Tconv (blue), Treg (red) and CD8 T cells (black) in 8 tumor samples. T cell subsets were identified as in Figure 1. Error bars represent standard deviation from the average. The degree of statistical significance between populations indicated on top of the graph (****: p<0.0001).