AIR binding modes. (A) BCR/antibody broadly specific binding (PDB accession codes: 1IGY and 7T3D). (B) BCR/antibody cross-reactive binding (PDB accession codes: 1IGY, 5UTY and 7T3D). (C) BCR/antibody polyreactivity binding (PDB accession codes: 1IGY, 6DZL, 6Q23, 7T3D). (D) TCR promiscuous binding (PDB accession codes: 3QDG, 7N5C, 4MAY).