Prevalence of Severe Acute Respiratory Syndrome Coronavirus 2 Neutralizing Antibodies in Egyptian Convalescent Plasma Donors.

Mokhtar R Gomaa,Ghazi Kayali,Noura M Abo Shama,Mohamed El Sayes,Ibrahim Y Abdel Messih,Ahmed El Taweel,Wael H Roshdy,Omnia Kutkat,Ahmed Kandeil,Mahmoud Shehata,Yassmin Moatasim,Sara H Mahmoud,Mohamed Elbadry,Mohamed A Ali,Ahmed Mostafa,Mina Nabil Kamel ,Mohamed A Elgohary ,Ahmed S Kayed ,Rabeh El‐Shesheny ,Salwa H Ahmed ,Osama Hassan Bakheet ,Naguib N Nassif

doi:10.3389/fmicb.2020.596851

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.

Highlights

According to the World Health Organization’s (WHO) COVID-19 situation report number 181, the world has reported almost 14 million cases and 6,00,000 deaths (4.2% case fatality rate; WHO, 2020a)
We initially investigated potential assays to test the sera to determine antibody levels and suitability for use as convalescent plasma therapy in comparison to plaque reduction neutralization (PRNT) which is considered the golden standard for measuring neutralizing antibody titers
The first set of 40 plasma samples were tested by PRNT, chemiluminescence, and MN using 200, 100, and 50 tissue culture infectious dose 50 (TCID50)/ml virus dilutions

Summary

Introduction

According to the World Health Organization’s (WHO) COVID-19 situation report number 181, the world has reported almost 14 million cases and 6,00,000 deaths (4.2% case fatality rate; WHO, 2020a). This disease, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), was first reported in China in December 2019. As with other infectious diseases, an effective vaccine would be the best weapon to slow the spread of SARS-CoV-2 Neutralizing Antibodies in Plasma Donors the virus but this is not yet available. According to the WHO, there are currently 10 candidate vaccines in clinical evaluation while 126 others are in pre-clinical phases (WHO, 2020b). Several therapeutics are currently being tested through the WHO’s “Solidarity” trial and other trials including remdesivir, chloroquine and hydroxychloroquine, lopinavir and ritonavir, and lopinavir + ritonavir + interferon-beta (Brown and Mccullough, 2020)

Methods

Results

Conclusion