Development of a pseudotyped lentivirus-based assay to measure neutralizing antibody activity against SARS-CoV-2 in Mexico

Abstract

The SARS-CoV-2 virus is responsible for the COVID-19 pandemic declared by the WHO in March 2020, which has caused more than 172 million confirmed cases and 3.69 million deaths worldwide to date. Infection with SARS-CoV-2 leads to the development of antibodies in patients. The presence of neutralizing antibodies protects against SARS-CoV-2 infections and is an essential parameter that confirms the success of vaccination. The titration of neutralizing antibodies by classical methods is not trivial since it requires the use of replicative virus, which implies a high risk of infection and requires facilities certified with the BSL-3 biosafety level. Mexico is one of the countries most affected by SARS-CoV-2 and there are not enough facilities to carry out effective immunity monitoring. Here, this thesis presents the results of a multi-institutional national collaboration in the design of a non-replicative pseudovirus that expresses the SARS-CoV-2 spike protein on its surface, which is applied in the development of a method for quantifying SARS-CoV neutralizing antibodies. The development of this assay will facilitate the characterization and monitoring of humoral immunity against SARS-CoV-2, and can be easily modified to monitor immunity against emerging variants in the country. To the best of our knowledge, this work presents the first report of measuring neutralizing antibody to SARS-CoV-2 in the Mexican population using a pseudovirus system.