AUTHOR=Gomaa Mokhtar R. , Kandeil Ahmed , Mostafa Ahmed , Roshdy Wael H. , Kayed Ahmed E. , Shehata Mahmoud , Kutkat Omnia , Moatasim Yassmin , El Taweel Ahmed , Mahmoud Sara H. , Kamel Mina Nabil , Abo Shama Noura M. , El Sayes Mohamed , El-Shesheny Rabeh , Bakheet Osama H. , Elgohary Mohamed A. , Elbadry Mohamed , Nassif Naguib N. , Ahmed Salwa H. , Abdel Messih Ibrahim Y. , Kayali Ghazi , Ali Mohamed A. TITLE=Prevalence of Severe Acute Respiratory Syndrome Coronavirus 2 Neutralizing Antibodies in Egyptian Convalescent Plasma Donors JOURNAL=Frontiers in Microbiology VOLUME=11 YEAR=2020 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.596851 DOI=10.3389/fmicb.2020.596851 ISSN=1664-302X ABSTRACT=

Using convalescent plasma as immunotherapy is an old method for treatment of infectious diseases. Several countries have recently allowed the use of such therapy for the treatment of COVID-19 patients especially those who are critically ill. A similar program is currently being tested in Egypt. Here, we tested 227 plasma samples from convalescent donors in Egypt for neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using a microneutralization (MN) assay. A third of the tested samples did not have antibody titers and 58% had titers between 1:10 and 1:80. Only 12% had titers >1:160. We also compared MN assays using different virus concentrations, plaque reduction neutralization (PRNT) assays, and a chemiluminescence assay that measures immunoglobulin G (IgG) binding to N and S proteins of SARS-CoV-2. Our results indicated that a MN assay using 100 TCID50/ml provides comparable results to PRNT and allows for high throughput testing.