Interchangeability of the Assays Used to Assess the Activity of Anti-SARS-CoV-2 Monoclonal Antibodies

Brady T Hickerson; Alexey M Khalenkov; Tao Xie; David M Frucht; Dorothy E Scott; Natalia A Ilyushina

doi:10.3390/v15081698

Interchangeability of the Assays Used to Assess the Activity of Anti-SARS-CoV-2 Monoclonal Antibodies

Viruses. 2023 Aug 5;15(8):1698. doi: 10.3390/v15081698.

Authors

Brady T Hickerson¹, Alexey M Khalenkov², Tao Xie¹, David M Frucht¹, Dorothy E Scott², Natalia A Ilyushina¹

Affiliations

¹ Division of Biotechnology Review and Research II, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA.
² Division of Plasma Derivatives, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA.

Abstract

The recent global COVID-19 pandemic caused by SARS-CoV-2 lasted for over three years. A key measure in combatting this pandemic involved the measurement of the monoclonal antibody (mAb)-mediated inhibition of binding between the spike receptor-binding domain (RBD) and hACE2 receptor. Potency assessments of therapeutic anti-SARS-CoV-2 mAbs typically include binding or cell-based neutralization assays. We assessed the inhibitory activity of five anti-SARS-CoV-2 mAbs using ELISA, surface plasmon resonance (SPR), and four cell-based neutralization assays using different pseudovirus particles and 293T or A549 cells expressing hACE2 with or without TMPRSS2. We assessed the interchangeability between cell-based and binding assays by applying the Bland-Altman method under certain assumptions. Our data demonstrated that the IC₅₀ [nM] values determined by eight neutralization assays are independent of the cell line, presence of TMPRSS2 enzyme on the cell surface, and pseudovirus backbone used. Moreover, the Bland-Altman analysis showed that the IC₅₀ [nM] and K_D [nM] values determined by neutralization/ELISA or by SPR are equivalent and that the anti-spike mAb activity can be attributed to one variable directly related to its tertiary conformational structure conformation, rate dissociation constant K_off. This parameter is independent from the concentrations of the components of the mAb:RBD:hACE2 complexes and can be used for a comparison between the activities of the different mAbs.

Keywords: Bland–Altman analysis; ELISA; antiviral activity; method interchangeability; monoclonal antibody; neutralization assay; potency; surface plasmon resonance.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.

MeSH terms

A549 Cells
Antibodies, Monoclonal
Antibodies, Viral
COVID-19*
Humans
Pandemics
SARS-CoV-2

Substances

Antibodies, Monoclonal
Antibodies, Viral

Grants and funding

Brady T. Hickerson was supported in part by an appointment to the Research Participation Program in the Office of Biotechnology Products, Center for Drug Evaluation and Research at the U.S. Food and Drug Administration by the Oak Ridge Institute for Science and Education (ORISE) through an interagency agreement between the FDA and the U.S. Department of Energy. This work was supported in whole or in part by intramural research funds from the FDA Office of Biotechnology Products.