Wang et al. focused on improving the potency and specificity of mAbs targeting cancer- and infection-associated carbohydrates. Using structure-based rational design and directed evolution, variants of mAb735 – a modest-affinity, polysialic acid (polySia)-specific antibody – were generated (scFv and IgG formats) with significantly increased affinity (4- to 7-fold) compared to parental mAb735. Affinity-matured mAb735 IgG variants bound more avidly to polySia-positive tumor cell lines, and demonstrated increased functional potency and tumor cell killing, including ADCC and CDC, providing a framework for enhancing the promise of anti-glycan Abs.
Contributed by Katherine Turner
ABSTRACT: Monoclonal antibodies (mAbs) that specifically recognize cell surface glycans associated with cancer and infectious disease hold tremendous value for basic research and clinical applications. However, high-quality anti-glycan mAbs with sufficiently high affinity and specificity remain scarce, highlighting the need for strategies that enable optimization of antigen-binding properties. To this end, we engineered the affinity of a polysialic acid (polySia)-specific antibody called mAb735, which possesses only modest affinity. Using a combination of rational design and directed evolution, we isolated several affinity-matured IgG variants with _5- to 7-fold stronger affinity for polySia relative to mAb735. The higher affinity IgG variants opsonized polySia-positive cancer cells more avidly and triggered greater antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Collectively, these results demonstrate the effective application of molecular evolution techniques to an important anti-glycan antibody, providing insights into its carbohydrate recognition and uncovering variants with greater therapeutic promise due to their enhanced affinity and potency.
Author Info: (1) Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Olin Hall, Ithaca, NY 14853, USA. (2) Robert F. Smith School of Chemical and Biomolecular E
Author Info: (1) Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Olin Hall, Ithaca, NY 14853, USA. (2) Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Olin Hall, Ithaca, NY 14853, USA. (3) Nancy E. and Peter C. Meinig School of Biomedical Engineering School of Biomedical Engineering, Cornell University, Olin Hall, Ithaca, NY 14853, USA. (4) Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Olin Hall, Ithaca, NY 14853, USA. (5) Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Olin Hall, Ithaca, NY 14853, USA; Nancy E. and Peter C. Meinig School of Biomedical Engineering School of Biomedical Engineering, Cornell University, Olin Hall, Ithaca, NY 14853, USA; Cornell Institute of Biotechnology, Cornell University, 130 Biotechnology Building, Ithaca, NY 14853, USA. Electronic address: md255@cornell.edu.
