Fig 1: Antigen‐blocking capability and protease cleavage efficiency of pro‐Nivolumab Immunoglobulin G (IgG) (a) The antigen‐binding ability of Nivolumab IgG (blue line), Nivolumab IgG + matrix metalloproteinase‐2 (MMP‐2) (green line), pro‐Nivolumab IgG (red line), and pro‐Nivolumab IgG + MMP‐2 (purple line) was assessed by PD‐1‐based enzyme‐linked immunosorbent assay. (b) A detailed investigation of cleavage progression over time: 1.11 μg of pro‐Nivolumab IgG was incubated with 2 ng of recombinant human MMP‐2 in a 250:1 ratio at 37°C for 0, 1, 5, 10, 30, 60, and 90 min. The levels of pro‐Nivolumab IgG's LC and HC that were cleaved and uncleaved were discerned using goat anti‐human IgG F(ab')2‐HRP and goat anti‐human IgG Fc‐HRP, respectively, with Western blot. (c) Band quantification from panel (b) and Figure S2B: Percentages of cleaved and uncleaved pro‐Nivolumab light chain (LC) and heavy chain (HC) were quantified using Gel‐Pro software. The data represent two independent experiments. Error bars indicate standard deviation.