| Abstract [eng] |
Evaluation of the Interaction Between Specific Monoclonal and Heavy-Chain Antibodies with the SARS-CoV-2 Spike Protein Using Total Internal Reflection Ellipsometry During the study, the interaction between covalently immobilized SARS-CoV-2 Spike protein and the heavy-chain monoclonal antibodies Sb14, Sb15, Sb68, as well as the human monoclonal antibody CR3022, was investigated. After selecting appropriate conditions for the covalent immobilization of the SARS-CoV-2 S protein, a real-time total internal reflection ellipsometry method was employed. This approach enabled the determination of changes in ellipsometric parameters during the interaction of antibodies with the SARS-CoV-2 S protein. Two mathematical models were applied to evaluate the interactions. An optical model was used to calculate the surface mass density, while a two-step binding model enabled the determination of kinetic parameters and thermodynamic characteristics of the interactions. The results showed that following interaction with monoclonal antibodies, the highest surface mass density was observed after binding with Sb15, whereas the lowest was detected after interaction with the human monoclonal antibody CR3022. All investigated monoclonal antibodies exhibited high affinity toward the SARS-CoV-2 S protein. Sb14 demonstrated the most pronounced binding properties, characterized by a picomolar equilibrium dissociation constant (KD = 2.10 × 10⁻¹¹ M), the highest association rate constant (ka = 4.76 × 10¹⁰), and the most negative Gibbs free energy value (−59.9 kJ/mol), indicating an exceptionally strong and thermodynamically favorable antibody–antigen interaction. |
