Variable heavy-variable light domain and Fab-arm CrossMabs with charged residue exchanges to enforce correct light chain assembly.
Regula, J.T., Imhof-Jung, S., Molhoj, M., Benz, J., Ehler, A., Bujotzek, A., Schaefer, W., Klein, C.(2018) Protein Eng Des Sel 31: 289-299
- PubMed: 30169707 
- DOI: https://doi.org/10.1093/protein/gzy021
- Primary Citation of Related Structures:  
6GHG - PubMed Abstract: 
Technologies for the production of bispecific antibodies need to overcome two major challenges. The first one is correct heavy chain assembly, which was solved by knobs-into-holes technology or charge interactions in the CH3 domains. The second challenge is correct light chain assembly. This can be solved by engineering the Fab-arm interfaces or applying the immunoglobulin domain crossover approach. There are three different crossovers possible, namely Fab-arm, constant domain and variable domain crossovers. The CrossMabCH1-CL exchange does not lead to the formation of unexpected side products, whereas the CrossMabFab and the CrossMabVH-VL formats result in the formation of typical side products. Thus, CrossMabCH1-CL was initially favored for therapeutic antibody development. Here, we report a novel improved CrossMab design principle making use of site-specific positional exchanges of charged amino acid pairs in the constant domain of these CrossMabs to enable the correct light chain assembly in the CrossMabVH-VL and improvements for the CrossMabFab design.
Organizational Affiliation: 
Roche Pharmaceutical Research and Early Development, Large Molecule Research, Roche Innovation Center Munich, Penzberg, Germany.