Antibody Structure & Biosimilars Comparability Analysis Services
SARomics Biostructures’ team possesses extensive expertise in X-ray and NMR analysis of monoclonal antibody and antibody-antigen complex structures. This includes rigorous structural characterization and comparability studies of biosimilars’ higher-order structure (HOS) using 2D-NMR spectroscopy.y.
Antibody Structure
We can assist you in determining the 3D structure of antibodies and Fab-antigen complexes. Through our gene-to-structure capabilities, we can also help you produce the antigen.
Comparability Analysis
Structural characterization and comparability studies of biosimilars’ higher-order structure (HOS) using 13C-natural abundance 2D-NMR spectroscopy.
Antibody Structure Analysis
SARomics Biostructures’ team has extensive experience in antibody structure and biosimilars comparability analysis by X-ray crystallography and NMR spectroscopy. The structural characterization and comparability studies of biosimilars’ higher-order structure (HOS) uses 13C-natural abundance 2D-NMR spectroscopy. All our studies include biophysical characterization of the state of the monoclonal antibodies and biosimilars in solution using biophysical methods.
More detailed, monoclonal antibody structure services can help you with the following:
- Epitope definition to file stronger IP.
- Understanding the mode of action.
- Structure-based antibody engineering: affinity maturation, humanization, antibody-drug conjugates (ADC), etc.
- Structural characterization of biologics for regulatory purposes.
- Assessing the comparability of a biosimilar antibody and its reference product.
For antibody-antigen co-crystallization, please find below a list of our FastLane™ Premium library extracellular proteins targeted by therapeutic antibodies. These proteins are available in our laboratory for immediate co-crystallization. You can view the full list of FastLane™ structures on our crystallography services page.
Comparability Analysis of Biosimilars Using NMR Spectroscopy
Assessing the comparability of a therapeutic biosimilar is critical to developing new products that adhere to patient safety principles (see our blog post on the subject). The NMR-based approach offered by SARomics Biostructures is currently the most efficient HOS comparability assessment approach at atomic resolution. Please see our blog post on comparing the experimental methods for assessing a biosimilar’s structural comparability.
At SARomics Biostructures, we use advanced NMR spectroscopy, which makes it possible to acquire a unique fingerprint representation of the 3D conformation of large, complex molecules like biologics. For biosimilar comparability assessment, 2D 13C NMR spectra of the methyl region of the biomolecules are acquired, and the biosimilar and originator spectra are compared. The method is based on natural abundance and does not require additional expensive labeling. By matching the NMR fingerprint of a given protein to its high-resolution 3D structure, determined, e.g., by X-ray crystallography, or to a fingerprint of another protein batch of the therapeutic monoclonal antibody or its biosimilar, we can rapidly assess and analyze comparability and show that the molecules, for example, a biosimilar and its originator, or different batches or alternative preparations of the same biologic, have identical HOS. In addition, the biomolecules can be studied in the formulation buffer for formulation optimization and batch comparison. Depending on the biomolecule, around 1-2 mg of protein can be sufficient for HOS analysis.
Case Studies Of Antibody-Antigen Complex Structures
Please find the list of recent case studies involving antibody structures complexed with antigens. The studies were published in reputable journals such as PNAS, Nat Comm, Cell Reports, iScience, Cancer Ther, Blood Adv, and Structure. For more information about the publications, please refer to the linked PDF. The determined structures include:
- Bispecific anti-Met/EpCAM mAb MM-131 in complex with its antigens (Merrimack Pharmaceuticals).
- ALPN-202 (An engineered CD80 variant fusion therapeutic) in complex with PD-L1 (Alpine Immune Sciences).
- SRF388 Fab in complex IL-27 (Surface Oncology Inc.),
- ActRIIB-Alk4-Fc in complex with activin A and anti-ActRIIB Fab (Acceleron Pharma).
- ALG.APV-527 (Fab1618) in complex with 4-1BB (CD137) (Alligator Bioscience AB).
- Glenzocimab Fab in complex with platelet glycoprotein VI (Acticor Biotech),
- DutaFab (Roche) in complex with its antigens PDGF and VEGFA.
- Dusquetide in complex with p62 (SQSTM1) ZZ domain (Soligenix, Inc.)
Recent Publication: The structure of unique light chain-driven bispecific antibodies
P Malinge, X Chauchet, J Bourguignon, N Bosson, S Calloud, T Bautzova, M Borlet, M Laursen, V Kelpsas, N Rose, F Gueneau, U Ravn, G Magistrelli & N Fischer (2024).
Structural analysis of light chain-driven bispecific antibodies targeting CD47 and PD-L1. mAbs 16, NO. 1, 2362432.
https://doi.org/10.1080/19420862.2024.2362432
The authors developed a bispecific antibody format, which, unlike natural antibodies that mainly rely on the heavy chain (HC), drives antigen binding and specificity using the light chain (LC). To better understand epitope-paratope interactions in the antibody-antigen complex, the SARomics team determined the X-ray crystallographic structures of an antigen-binding fragment (Fab) in a complex with human CD47 and another Fab in a complex with human PD-L1 (one of the proteins in our FastLane™ Premium library). Structure analysis revealed the dominant contribution of the light chain, demonstrating that the light chain can also mediate high-affinity binding, enabling the creation of bispecific antibodies with native structures, thus enhancing the therapeutic potential. (PDB IDs: 8RP8 and 8RPB).
We invite you to visit our publications page for additional examples of projects we have contributed to.