Presence and Strength of Binding of IgM, IgG and IgA Antibodies Against SARS-CoV-2 During COVID-19 Infection

Science Direct, doi.org/10.1016/j.mex.2021.101432

Richard Schasfoort, Jos van Weperen, Margot van Amsterdam, Judicaël Parisot, Jan Hendriks, Michelle Koerselman, Marcel Karperien, Anouk Mentink, Martin Bennink, Hans Krabbe, Leon Terstappen, Leontine Mulder

Highlights

• Surface Plasmon Resonance imaging is an unprecedented technology for high throughput screening of antibody profiling of COVID-19 patients.
• Fingerprinting of isotypes IgM, IgG and IgA can be performed for 384 patients in one run.
• Severity of the disease correlates well with the total anti-RBD of SARS-CoV-2 concentration in COVID-19 patients
• Affinity equilibrium constant (K_D) of the polyclonal antibody binding was directly proportional to the off-rate (k_d) simplifying the screening.
• Screening of the strength of binding of anti RBD antibodies was possible in high throughput and in one run together with the isotype analysis in the LSA SPR imager.
• An affinity maturation effect was shown for patients recovering from COVID-19.
• A tool is now available to test the quality of the immune reaction of individuals to SARS-CoV-2 and its mutants in vaccination programs.

Abstract

Surface Plasmon Resonance imaging (SPRi) was used to determine the presence and strength of binding of IgG, IgM and IgA against the Receptor Binding Domain (RBD) of SARS-CoV-2 in sera of 119 COVID-19 patients. The SPRi assay measures the antibody isotype levels and the strength of binding to the RBD of ultimate 384 patient samples in one run. It turns out that during the course of the disease, the IgG levels and strength of binding increased while generally the IgM and IgA levels go down. Recovered patients all show high strength of binding of the IgG type to the RBD protein. The anti-RBD immunoglobulins SPRi assay provides additional insights in the immune status of patients recovering from COVID-19 and this new method can furthermore be applied for the assessment of the quality of the immune reaction of healthy individuals to SARS-CoV-2 in vaccination programs.