Neutralizing and binding activities against SARS-CoV-1/2, MERS-CoV, and human coronaviruses 229E and OC43 by normal human intravenous immunoglobulin derived from healthy donors in Japan.

Background: There are several types of coronaviruses that infect humans and cause disease. The latest is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is an emerging global threat with no current effective treatment. Normal intravenous immunoglobulin (N-IVIG) has been administered to coronavirus disease 2019 (COVID-19) patients to control severe inflammation and the cellular immune response. However, the neutralizing activity of N-IVIG against SARS-CoV-2 has not yet been fully evaluated. The aim of this study was to determine whether N-IVIG manufactured before the start of the COVID-19 pandemic contained IgG antibodies against the circulating human coronaviruses (HCoVs) that cross-react with the highly pathogenic coronaviruses SARS-CoV-1, Middle East respiratory syndrome coronavirus (MERS-CoV), and SARS-CoV-2. No cases of SARS-CoV-1 or MERS-CoV have been reported in Japan.

Study Design And Methods: The neutralizing and binding activities of N-IVIG against SARS-CoV-1, MERS-CoV, SARS-CoV-2, HCoV 229E, and HCoV OC43 were evaluated. Nine N-IVIG lots manufactured between 2000 and 2018, derived from donors in Japan, were tested. Binding activity was evaluated by indirect immunofluorescence assay.

Results: None of the N-IVIG lots tested displayed neutralizing or binding activity against SARS-CoV-1, MERS-CoV, or SARS-CoV-2. However, they displayed substantial neutralizing and binding activity against HCoV OC43 and weak neutralizing and substantial binding activity against HCoV 229E.

Conclusion: N-IVIG derived from healthy donors in Japan before the start of the COVID-19 pandemic had no direct effect against SARS-CoV-2. Further studies are warranted to determine the effects of N-IVIG manufactured after the start of the COVID-19 pandemic against SARS-CoV-2.