Iota-carrageenan neutralizes SARS-CoV-2 and inhibits viral replication in vitro
Martina Morokutti-Kurz, Maria Fröba, Philipp Graf, Maximilian Große, Andreas Grassauer, Janina Auth, Ulrich Schubert, Eva Prieschl-Grassauer
PLOS ONE, doi:10.1371/journal.pone.0237480
In the absence of a vaccine and other effective prophylactic or therapeutic countermeasures the severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) remains a significant public health threat. Attachment and entry of coronaviruses including SARS-CoV-2 is mainly mediated by the spike glycoprotein. Here, we show that iota-carrageenan can inhibit the cell entry of the SARS-CoV-2 spike pseudotyped lentivirus in a dose dependent manner. SARS-CoV-2 spike pseudotyped lentivirus particles were efficiently neutralized with an IC 50 value of 2.6 μg/ml iota-carrageenan. Experiments with patient isolated wild type SARS-CoV-2 virus showed an inhibition of replication in a similar range. In vitro data on iotacarrageenan against various Rhino-and endemic Coronaviruses showed similar IC 50 values and translated readily into clinical effectiveness when a nasal spray containing iota-carrageenan demonstrated a reduction of severity and duration of symptoms of common cold caused by various respiratory viruses. Accordingly, our in vitro data on SARS-CoV-2 spike pseudotyped lentivirus and replication competent SARS-CoV-2 suggest that administration of iota-carrageenan may be an effective and safe prophylaxis or treatment for SARS-CoV-2 infections.
Supporting information S1
Author Contributions Conceptualization: Martina Morokutti-Kurz, Andreas Grassauer, Ulrich Schubert, Eva Prieschl-Grassauer. Data curation: Martina Morokutti-Kurz, Maria Fro ¨ba, Philipp Graf, Maximilian Große, Janina Auth, Ulrich Schubert, Eva Prieschl-Grassauer. Formal analysis: Martina Morokutti-Kurz, Maria Fro ¨ba, Philipp Graf, Maximilian Große, Andreas Grassauer, Janina Auth. Funding acquisition: Andreas Grassauer, Ulrich Schubert, Eva Prieschl-Grassauer. Investigation: Maria Fro ¨ba, Philipp Graf, Maximilian Große, Janina Auth. Methodology: Martina Morokutti-Kurz, Maria Fro ¨ba, Janina Auth, Ulrich Schubert. Project administration: Janina Auth, Eva Prieschl-Grassauer. Resources: Andreas Grassauer, Janina Auth, Ulrich Schubert, Eva Prieschl-Grassauer. Software: Eva Prieschl-Grassauer. Supervision: Ulrich Schubert. Validation: Eva Prieschl-Grassauer. Visualization: Eva Prieschl-Grassauer. Writing -original draft: Martina Morokutti-Kurz, Andreas Grassauer, Ulrich Schubert, Eva Prieschl-Grassauer. Writing -review & editing: Martina Morokutti-Kurz, Maria Fro ¨ba, Maximilian Große, Andreas Grassauer, Ulrich Schubert, Eva Prieschl-Grassauer.
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