%0 Journal Article %A José-María Díez %A Carolina Romero %A Júlia Vergara-Alert %A Melissa Belló-Perez %A Jordi Rodon %A José Manuel Honrubia %A Joaquim Segalés %A Isabel Sola %A Luis Enjuanes %A Rodrigo Gajardo %T Cross-neutralization activity against SARS-CoV-2 is present in currently available intravenous immunoglobulins %D 2020 %R 10.1101/2020.06.19.160879 %J bioRxiv %P 2020.06.19.160879 %X Background There is a crucial need for effective therapies that are immediately available to counteract COVID-19 disease. Recently, ELISA binding cross-reactivity against components of human epidemic coronaviruses with currently available intravenous immunoglobulins (IVIG) Gamunex-C and Flebogamma DIF (5% and 10%) have been reported. In this study, the same products were tested for neutralization activity against SARS-CoV-2, SARS-CoV and MERS-CoV and their potential as an antiviral therapy.Methods The neutralization capacity of six selected lots of IVIG was assessed against SARS-CoV-2 (two different isolates), SARS-CoV and MERS-CoV in cell cultures. Infectivity neutralization was measured by determining the percent reduction in plaque-forming units (PFU) and by cytopathic effects for two IVIG lots in one of the SARS-CoV-2 isolates. Neutralization was quantified using the plaque reduction neutralization test 50 (PRNT50) in the PFU assay and the half maximal inhibitory concentration (IC50) in the cytopathic/cytotoxic method (calculated as the minus log10 dilution which reduced the viral titer by 50%).Results All IVIG preparations showed neutralization of both SARS-CoV-2 isolates, ranging from 79 to 89.5% with PRNT50 titers from 4.5 to >5 for the PFU method and ranging from 47.0%-64.7% with an IC50 ~1 for the cytopathic method. All IVIG lots produced neutralization of SARS-CoV ranging from 39.5 to 55.1 % and PRNT50 values ranging from 2.0 to 3.3. No IVIG preparation showed significant neutralizing activity against MERS-CoV.Conclusion In cell culture neutralization assays, the tested IVIG products contain antibodies with significant cross-neutralization capacity against SARS-CoV-2 and SARS-CoV. However, no neutralization capacity was demonstrated against MERS-CoV. These preparations are currently available and may be immediately useful for COVID-19 management.Competing Interest StatementNeutralization experiments were funded by Grifols, the manufacturer of Flebogamma DIF and Gamunex-C. JVA, JR, MBP, JMH, IS, and LE declare having no other conflict of interest. JMD, CR and RG are full-time employees of Grifols. %U https://www.biorxiv.org/content/biorxiv/early/2020/06/19/2020.06.19.160879.full.pdf