title: Production, Characterization, and Biological Evaluation of Well-Defined IgG1 Fc Glycoforms as a Model System for Biosimilarity Analysis.
abstract: Four different well-defined IgG1 Fc glycoforms are proposed as a model system to examine important biological and physicochemical features for protein drug biosimilar analyses. The IgG1 Fc glycoforms were produced by yeast expression combined with in vitro enzymatic synthesis as a series of sequentially truncated high-mannose IgG1 Fc glycoforms with an anticipated range of biological activity and structural stability. Initial characterization with mass spectrometry, SDS-PAGE, size exclusion HPLC, and capillary isoelectric focusing confirmed that the glycoproteins are overall highly similar with the only major difference being glycosylation state. Binding to the activating Fc receptor, FcγRIIIa was used to evaluate the potential biological activity of the IgG1 Fc glycoproteins. Two complementary methods using biolayer interferometry, 1 with protein G-immobilized IgG1 Fc and the other with streptavidin-immobilized FcγRIIIa, were developed to assess FcγRIIIa affinity in kinetic binding studies. The high-mannose IgG1 Fc and Man5-IgG1 Fc glycoforms were highly similar to one another with high affinity for FcγRIIIa, whereas GlcNAc-Fc had weak affinity, and the nonglycosylated N297Q-Fc had no measurable affinity for FcγRIIIa. These 4 IgG1 Fc glycoforms were also evaluated in terms of physical and chemical stability profiles and then used as a model system to mathematically assess overall biosimilarity, as described in a series of companion articles.
authors: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047.
authors: Solomon Z
authors: SZ
authors: Okbazghi
authors: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047; Department of Pharmaceutical Chemistry, Macromolecule and Vaccine Stabilization Center, University of Kansas, Lawrence, Kansas 66047.
authors: Apurva S
authors: AS
authors: More
authors: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047.
authors: Derek R
authors: DR
authors: White
authors: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047.
authors: Shaofeng
authors: S
authors: Duan
authors: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047.
authors: Ishan S
authors: IS
authors: Shah
authors: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047; Department of Pharmaceutical Chemistry, Macromolecule and Vaccine Stabilization Center, University of Kansas, Lawrence, Kansas 66047.
authors: Sangeeta B
authors: SB
authors: Joshi
authors: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047; Department of Pharmaceutical Chemistry, Macromolecule and Vaccine Stabilization Center, University of Kansas, Lawrence, Kansas 66047.
authors: C Russell
authors: CR
authors: Middaugh
authors: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047; Department of Pharmaceutical Chemistry, Macromolecule and Vaccine Stabilization Center, University of Kansas, Lawrence, Kansas 66047.
authors: David B
authors: DB
authors: Volkin
authors: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047. Electronic address: tolbert@ku.edu.
authors: Thomas J
authors: TJ
authors: Tolbert
mesh_terms: D059451:Biosimilar Pharmaceuticals / Q000138:chemical synthesis* / Q000378:metabolism; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006023:Glycoproteins / Q000032:analysis / Q000138:chemical synthesis* / Q000378:metabolism; D006031:Glycosylation; D007141:Immunoglobulin Fc Fragments / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D007074:Immunoglobulin G / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology
chemical_list: D059451:Biosimilar Pharmaceuticals; D006023:Glycoproteins; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G
keywords: IgG antibody; biopharmaceuticals characterization; biosimilar; follow-on biologics; glycoprotein; glycosylation; receptors