The crystal structure of 8C11Fab in complex with the E2s domain. (A) The structures of the E2s-8C11Fab complexes. (B) The epitope of mAb 8C11 on E2s, including E479, T497, R512, K534, H577 and R578 on the recombinant HEV capsid protein at the interface with an interacting Fab of the 8C11. (C) Interacting residues at the interface between E2s and 8C11Fab. The interactions include hydrogen bonds, Pi-Pi interaction and salt bridge.