Purpose-Oriented Antibody Libraries Incorporating Tailored CDR3 Sequences

Abstract

The development of in vitro antibody selection technologies has allowed overcoming some limitations inherent to the hybridoma technology. In most cases, large repertoires of antibody genes have been assembled to create highly diversified libraries allowing the isolation of antibodies recognizing virtually any antigen. However, these universal libraries might not allow the isolation of antibodies with specific structural properties or particular amino acid contents that are rarely found in natural repertoires. Purpose-oriented libraries specially designed to incorporate desired characteristics have been successfully used. However, the workload required for library construction has limited the attractiveness of this approach compared to the use of large universal libraries. We have developed an approach to capture synthetic or natural diversity into the complementarity determining regions 3 (CDR3) of human antibody repertoires using Type IIS restriction enzymes. In this way, we generated several libraries either biased in amino acid content or towards long CDRH3 loops. The latter were successfully used to identify antibodies inhibiting the enzymatic activity of horseradish peroxidase, whereas libraries enriched in histidines allowed for the isolation of antibodies binding to human Fc in a pH-dependent manner. These libraries indicate that tailored diversification of CDR3 is sufficient to generate purpose-oriented libraries and isolate antibodies with uncommon properties.

Keywords

• monoclonal antibody
• phage display
• antibody library
• complementary determining region
• cryptic site
• pH-dependence