Figure 1.

Biologically relevant assembly of the PD-1-mAb059c complex structure. (a) Mixed Lymphocyte Reaction Assay. IFN-γ release is measured in the presence of different doses (10, 1, 0.1, 0.01 µg/ml) of mAb059c, nivolumab, pembrolizumab and control; Similar dose-dependent enhancement of the IFN-γ secretion by mAb059c, nivolumab, pembrolizumab references are observed with multiple DC and T-cell donor pairs. (b) In vivo efficacy study using the MC38 model in hPD-1 knock-in mice at a dose of 1 mg/kg. ***P < 0.001 vs IgG via Two-way ANOVA with Bonferroni multiple comparison test. Similar results are observed at 10 mg/kg dose (Tumor growth curves with all groups are shown in Supplementary Fig. S1); (c) The complex structure of PD-1-mAb059c is displayed as a cartoon representation. The surface of PD-1 is shown in purple. The heavy chain and light chain of mAb059c are shown in green and cyan, respectively. C’D/FG loops of PD-1 and the HCDR and LCDR loops of mAb059c are labeled in purple, green and cyan, respectively; (d) The mAb059c Fab-PD-1 association validated by SDS-PAGE gel. Lane 1, crystal harvested from 3 droplets (roughly 15~30 µg) and dissolved in well solution after washing 2 times; Lane 2, 2 µg of PD-1 alone; Lane 3, 1 µg of mAb059c Fab alone; the rest of the blank area in the gel image was cropped (the full-length gel is presented in Supplementary Fig. S2).