Mapping monoclonal antibody structure by 2D 13C NMR at natural abundance.
Monoclonal antibodies (mAbs) represent an important and rapidly growing class of biotherapeutics. Correct folding of a mAb is critical for drug efficacy, while misfolding can impact safety by eliciting unwanted immune or other off-target responses. Robust methods are therefore needed for the precise measurement of mAb structure for drug quality assessment and comparability. To date, the perception in the field has been that NMR could not be applied practically to mAbs due to the size (∼150 kDa) and complexity of these molecules, as well as the insensitivity of the method. The feasibility of applying NMR methods to stable isotope-labeled, protease-cleaved, mAb domains (Fab and Fc) has been demonstrated from both E. coli and Chinese hamster ovaries (CHO) cell expression platforms; however, isotopic labeling is not typically available when analyzing drug products. Here, we address the issue of feasibility of NMR-based mapping of mAb structure by demonstrating for the first time the application of a 2D (13)C NMR methyl fingerprint method for structural mapping of an intact mAb at natural isotopic abundance. Further, we show that 2D (13)C NMR spectra of protease-cleaved Fc and Fab fragments can provide accurate reporters on the domain structures that can be mapped directly to the intact mAb. Through combined use of rapid acquisition and nonuniform sampling techniques, we show that these Fab and Fc fingerprint spectra can be rapidly acquired in as short as approximately 30 min.
Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology and the University of Maryland, 9600 Gudelsky Dr., Rockville, Maryland 20850, United States.
Luke W
LW
Arbogast
Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology and the University of Maryland, 9600 Gudelsky Dr., Rockville, Maryland 20850, United States.
Robert G
RG
Brinson
Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology and the University of Maryland, 9600 Gudelsky Dr., Rockville, Maryland 20850, United States.
John P
JP
Marino
D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D016466:CHO Cells; D066241:Carbon-13 Magnetic Resonance Spectroscopy; D006224:Cricetinae; D003412:Cricetulus; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry*; D007141:Immunoglobulin Fc Fragments / Q000737:chemistry*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation
D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments