2. Academic Validation
  3. Site-selective chemoenzymatic glycoengineering of Fab and Fc glycans of a therapeutic antibody

Site-selective chemoenzymatic glycoengineering of Fab and Fc glycans of a therapeutic antibody

  • Proc Natl Acad Sci U S A. 2018 Nov 20;115(47):12023-12027. doi: 10.1073/pnas.1812833115.
John P Giddens 1 2,  Joseph V Lomino 2,  David J DiLillo 3,  Jeffrey V Ravetch 4,  Lai-Xi Wang 5 2
Affiliations

Affiliations

  • 1 Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742.
  • 2 Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201.
  • 3 Laboratory of Molecular Genetics and Immunology, The Rockefeller University, New York, NY 10065.
  • 4 Laboratory of Molecular Genetics and Immunology, The Rockefeller University, New York, NY 10065 [email protected] [email protected].
  • 5 Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742; [email protected] [email protected].
PMID: 30397147 DOI: 10.1073/pnas.1812833115
Abstract

The N-glycans attached to the Fab and Fc domains play distinct roles in modulating the functions of Antibodies. However, posttranslational site-selective modifications of glycans in Antibodies and other multiply glycosylated proteins remain a challenging task. Here, we report a chemoenzymatic method that permits independent manipulation of the Fab and Fc N-glycans, using cetuximab as a model therapeutic monoclonal antibody. Taking advantage of the substrate specificity of three endoglycosidases (Endo-S, Endo-S2, and Endo-F3) and their glycosynthase mutants, together with an unexpected substrate site-selectivity of a Bacterial α1,6-fucosidase from Lactobacillus casei (AlfC), we were able to synthesize an optimal homogeneous glycoform of cetuximab in which the heterogeneous and immunogenic Fab N-glycans were replaced with a single sialylated N-glycan, and the core-fucosylated Fc N-glycans were remodeled with a nonfucosylated and fully galactosylated N-glycan. The glycoengineered cetuximab demonstrated increased affinity for the FcγIIIa receptor and significantly enhanced antibody-dependent cell-mediated cytotoxicity (ADCC) activity.

Keywords

Fc receptor; N-glycan; antibody glycosylation; antibody therapy; glycoengineering.

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