PT  - JOURNAL ARTICLE
AU  - Carina Conzelmann
AU  - Andrea Gilg
AU  - Rüdiger Groß
AU  - Desirée Schütz
AU  - Nico Preising
AU  - Ludger Ständker
AU  - Bernd Jahrsdörfer
AU  - Hubert Schrezenmeier
AU  - Konstantin M. J. Sparrer
AU  - Thomas Stamminger
AU  - Steffen Stenger
AU  - Jan Münch
AU  - Janis A. Müller
TI  - An enzyme-based immunodetection assay to quantify SARS-CoV-2 infection
AID  - 10.1101/2020.06.14.150862
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.06.14.150862
4099  - http://biorxiv.org/content/early/2020/06/15/2020.06.14.150862.short
4100  - http://biorxiv.org/content/early/2020/06/15/2020.06.14.150862.full
AB  - SARS-CoV-2 is a novel pandemic coronavirus that caused a global health and economic crisis. The development of efficient drugs and vaccines against COVID-19 requires detailed knowledge about SARS-CoV-2 biology. Several techniques to detect SARS-CoV-2 infection have been established, mainly based on counting infected cells by staining plaques or foci, or by quantifying the viral genome by PCR. These methods are laborious, time-consuming and expensive and therefore not suitable for a high sample throughput or rapid diagnostics. We here report a novel enzyme-based immunodetection assay that directly quantifies the amount of de novo synthesized viral spike protein within fixed and permeabilized cells. This in-cell ELISA enables a rapid and quantitative detection of SARS-CoV-2 infection in microtiter format, regardless of the virus isolate or target cell culture. It follows the established method of performing ELISA assays and does not require expensive instrumentation. Utilization of the in-cell ELISA allows to e.g. determine TCID50 of virus stocks, antiviral efficiencies (IC50 values) of drugs or neutralizing activity of sera. Thus, the in-cell spike ELISA represents a promising alternative to study SARS-CoV-2 infection and inhibition and may facilitate future research.HighlightsDetermination of SARS-CoV-2 infection by enzymatically quantifying the expression of viral spike protein in bulk cell culturesTargeting a highly conserved region in the S2 subunit of the S protein allows broad detection of several SARS-CoV-2 isolates in different cell linesScreening of antivirals in microtiter format and determining the antiviral activity as inhibitory concentrations 50 (IC50)Competing Interest StatementThe authors have declared no competing interest.