Fig. 4: Blocking of integrin αvβ6-fibronectin binding by IgG from patients with ICI-induced colitis with anti-integrin αvβ6 autoantibodies.

a Inhibition of integrin αvβ6-fibronectin binding by IgG of patients with ICI-induced colitis with anti-integrin αvβ6 autoantibodies in the solid-phase binding assay. The cutoff OD value, defined as the mean plus three SDs of IgG from healthy volunteers, is indicated using a dashed line. IgG from six of eight (75%) patients with ICI-induced colitis with anti-integrin αvβ6 autoantibodies blocked integrin αvβ6-fibronectin binding. However, no control IgG showed blocking activity. b, c Peptide RGDS, but not RGES, dose-dependently impaired the binding of IgG of patients with ICI-induced colitis with anti-integrin αvβ6 autoantibodies against integrin αvβ6. The RGDS and RGES peptides represented the RGD and RGE motifs, respectively. The experiments were repeated independently twice with similar results. ICI immune checkpoint inhibitor, IgG immunoglobulin G, OD optical density, RGD Arg-Gly-Asp, RGDS Arg-Gly-Asp-Ser, RGE Arg-Gly-Glu, RGES Arg-Gly-Glu-Ser, SD standard deviation.