Antibody Engineering

Abstract

Advanced molecular biology techniques developed during the past few decades have allowed the industry to exploit and commercialize the natural defense mechanisms that antibodies provide. This review discusses the latest advances in antibody-engineering technologies to enhance clinical efficacy and outcomes. For the constant regions, the choice of the antibody class and isotype has to be made carefully to suit the therapeutic applications. Engineering of the Fc region, either by direct targeted mutagenesis or by modifying the nature of its N-glycan, has played an important role in recent years in increasing half-life or controlling effector functions. The variable regions of the antibody are responsible for binding affinity and exquisite specificity to the target molecule, which together with the Fc determine the drug's efficacy and influence the drug dose required to obtain the desired effectiveness. A key requirement during antibody development is therefore to affinity mature the variable regions when necessary, so that they bind the therapeutic target with sufficiently high affinity to guarantee effective occupancy over prolonged periods. If the antibody was obtained from a non-human source, such as rodents, a humanization process has to be applied to minimize immunogenicity while maintaining the desired binding affinity and selectivity. Finally, we discuss the next next-generation antibodies, such as antibody-drug conjugates, bispecific antibodies, and immunocytokines, which are being developed to meet future challenges.Monoclonal antibodies are enjoying outstanding commercial success, with 4 of the top 10 best-selling drugs. Although most of the preclinical and clinical experiences with therapeutic antibodies have been gained from the treatment of cancer and inflammatory diseases, effective therapy is not limited to these indications. For example, palivizumab (Synagis) has been approved for the prophylactic treatment for respiratory syncytial virus (RSV) infections and remains the only therapeutic antibody for the treatment of infectious diseases to date.In this article, we review the latest advances in antibody-engineering technologies to make an antibody clinically and commercially successful. We discuss the rationale behind the choice of immunoglobulin isotype and the protein engineering of the constant regions. This is followed by a review of the humanization strategy to minimize immunogenicity and the recent approaches to affinity mature the antigen binding of the antibody. Finally, we have an overview of the next-generation antibodies, such as antibody-drug conjugates, bispecific antibodies, and immunocytokines, which are being developed to meet future challenges. THE CONSTANT REGIONS: PROTEIN AND GLYCOENGINEERING OF THE FCThe Fc portion of the antibody, which determines its effector functions and is responsible for its pharmacokinetic properties, has to be carefully chosen to suit its therapeutic applications. To date, all of the approved therapeutic antibodies are of the immunoglobulin G (Ig...

Rapid Affinity Maturation of Novel Anti-PD-L1 Antibodies by a Fast Drop of the Antigen Concentration and FACS Selection of Yeast Libraries

“…Along with the identification of novel lead antibodies, many progresses have been done in antibody engineering, in order to improve the therapeutic efficacy and safety profile [7,8]. In particular, the improvement of the antibody affinity is crucial to increase efficacy and enhance clinical outcomes, and it is achieved by means of in vitro technologies that allow to reach picomolar affinities [14,24,26].…”

“…e market of mAbs is in constant increase, with 82 mAbs approved by the Food and Drug Administration (FDA) to date and hundreds being in clinical trials [5,6]. In parallel with the discovery of novel therapeutic mAbs, the field of antibody engineering is in constant development too, in order to improve various antibody properties for more effective therapies [7,8]. Of main importance is the affinity engineering, which contributes to increase binding selectivity too.…”

IL3RA-Targeting Antibody–Drug Conjugate BAY-943 with a Kinesin Spindle Protein Inhibitor Payload Shows Efficacy in Preclinical Models of Hematologic Malignancies

“…The IL3RA-specific hIgG1 antibody (IL3RA-Ab, TPP-9476) was generated by humanization of the murine anti-IL3RA antibody 7G3 [ 33 ] as described in Lerchen et al [ 22 ]. During a protein engineering process, which is meant to bring the amino acid sequence as close as possible to the next human germline [ 50 ], multiple variants were tested. The final version, TPP-9476, comprises several amino acid exchanges in the light and heavy chain that resulted in enhanced internalization.…”

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“…Recombinant monoclonal antibodies are made by clonal selection from phage, bacterial, fungal or mammalian antibody libraries, or by grafting cDNA encoding CDRs from an existing hybridoma into the DNA of a non-variable IgG framework (Hoogenboom, 2005;McConnell et al, 2012). The antibody clones can be expressed in stable producer cell lines (Lo et al, 2014). It is highly desirable, and no longer especially arduous, to sequence antibody genes and so immortalize 'good' hybridomas, before converting them into recombinant antibodies (Babrak et al, 2017;Chon and Zarbis-Papastoitsis, 2011).…”