Fig. 4.

Schematic overview of the IgG antibody structure and representative multispecific antibody formats at clinical stages. a The classical IgG antibody structure that consists of Fab and Fc regions. The single chain variable fragment (scFv) is a combination of the variable region of heavy chain (VH) and variable region of light chain (VL) domains. b Various multispecific antibody formats that are FDA-approved or under clinical studies. They are classified into the following categories: IgG-like constructs (with Fc region), non-IgG-like fragments (without Fc region). ScFv single-chain variable fragment, DVD-Ig dual-variable-domain immunoglobulin, BiTE bispecific T-cell engager, HLE-BiTE half-life-extended BiTE, TandAb tandem diabody, DART dual-affinity retargeting molecule, CODV cross-over dual variable region, TriKE trispecific NK-cell engager, TriTAC trispecific T-cell activation constructs