The influence of antibody fragment format on phage display based affinity maturation of IgG

• DOI: 10.4161/mabs.27227
• Publication Date: 2013-11-20T18:27:14Z
• Authors: Miriam Steinwand; Patrick Droste; Andrè Frenzel; Michael Hust; Stefan Dübel; Thomas Schirrmann
• Keywords: Fragment (logic)

Today, most approved therapeutic antibodies are provided as immunoglobulin G (IgG), whereas small recombinant antibody formats required for in vitro generation and engineering during drug development. Particularly,single chain (sc) fragments like scFv or scFab well suited phage display bacterial expression, but some have been found to lose affinity conversion into IgG.In this study, we compared the influence of format on maturation CD30-specific fragment SH313-F9, with overall objective being improvement IgG. The variable genes SH313-F9 were randomly mutated then cloned libraries encoding different formats, including scFv, Fab, scFabΔC, FabΔC. All tested except Fab allowed functional parental corresponding gene isolation candidates enhanced CD30 binding. Moreover, scFabΔC variants retained improved antigen binding after subcloning single encoded IgG-like scFv-Fc scIgG, lost IgGs.Only using Fab-like FabΔC format, which does not contain carboxy terminal cysteines, successful selection molecules that was Thus, IgGs is dependent employed screening. In only resulted efficient IgG higher by combination conformation Fab.