Figure 2. Overview of bispecific heterodimeric IgG antibodies with heterodimeric Fc-region. (A) Quadroma approach with isolation of the desired bispecific Triomab. (B) KiH approach with two different light chains based on in vitro assembly; the white circle indicates the lack of glycosylation due to expression in E. coli. (C) KiH approach with common light chain. (D) CrossMab^CH1-CL based on KiH approach in combination with light chain crossover. (E) (SEED)body approach based on strand exchange between IgG and IgA CH3 domains. (F) LUZ-Y with C-terminal fusion of a leucine zipper to the heavy chain to ensure HC heterodimerization and common light chain. The leucine zipper can subsequently be cleaved off proteolytically. For a more detailed description, refer to the text.