Cross-Neutralization Activity Against SARS-CoV-2 is Present in Currently Available Intravenous Immunoglobulins

Abstract

<b>Background:</b> Cross-reactivity against human coronaviruses with Flebogamma^® DIF and Gamunex^®-C, two available intravenous immunoglobulins (IVIG), has been reported. In this study, these IVIG were tested for neutralization activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), SARS-CoV and Middle East respiratory syndrome CoV (MERS-CoV). <b>Materials & methods:</b> Neutralization capacity of lots of IVIG manufactured prior to COVID-19 pandemic was assessed against these viruses in cell culture. Infectivity neutralization was quantified by percent reduction in plaque-forming units and/or cytopathic/cytotoxic methods. <b>Results:</b> All IVIG preparations showed neutralization of SARS-CoV-2 isolates. All IVIG lots produced neutralization of SARS-CoV. No IVIG preparation showed significant neutralizing activity against MERS-CoV. <b>Conclusion:</b> The tested IVIG contain antibodies with significant <i>in vitro</i> cross-neutralization capacity against SARS-CoV-2 and SARS-CoV, but not MERS-CoV. These preparations are currently under evaluation as potential therapies for COVID-19.