Correlation of humoral immune responses to different SARS-CoV-2 antigens with virus neutralizing antibodies and symptomatic severity in a German COVID-19 cohort

ABSTRACT

Monitoring the humoral protective immune response and its durability after SARS-CoV-2 infections is essential for risk assessment of reinfections, the improvement of diagnostic methods and the evaluation of vaccine trials. We have analyzed neutralizing antibodies and IgG responses specific to different antigens, including the inactivated whole-virion of SARS-CoV-2, the spike subunit 1 protein and its receptor binding domain, as well as the nucleocapsid protein. We show the dynamic developments of the responses from the early convalescent stages up to 9 months post symptoms onset in follow-up samples from 57 COVID-19 patients with varying clinical severity. By correlating antibody signals to neutralizing titres, valid diagnostic markers for the estimation of neutralizing protection could be identified.

KEYWORDS:

• COVID-19
• neutralizing antibodies
• inactivated SARS-CoV-2
• humoral immunity
• RBD-ELISA
• nucleocapsid-ELISA
• S1-ELISA

Acknowledgments

We thank Ulrike Ehlert and Steffen Jakob from the Department of Immunology at Fraunhofer Institute for Cell Therapy and Immunology as well as Florian Kutz, Anne Tako, Philine Weinbrecht, Kathrin Grabitz, Kathrin Schneider and Emily Gruber from the Department of Laboratory Medicine at Hospital St. Georg Leipzig for excellent technical assistance. We thank Jonas Schmidt-Chanasit (Bernhard Nocht Institute) for the supply with negative control serum samples.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This publication was supported by Saxon State Ministry for Science, Culture and Tourism (grant SaxoCOV) and the European Virus Archive GLOBAL (EVA-GLOBAL) project that has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 871029.