Development of human monoclonal antibodies against SARS-CoV-2

Abstract

SARS-CoV-2 is the pathogen responsible for the COVID-19 pandemic, affecting more than 131 million individuals, including 2.8 million deaths. To combat the pandemic, rapid antigen diagnostic kits have been proposed to be a solution for managing the pandemic whilst enabling a continuous economy, as they allow rapid testing (e.g. at point-of-entry) without the need for specialised labour or equipment. In order to develop test kits that have a higher sensitivity than those currently available, we aimed to identify and isolate monoclonal antibodies which target two previously identified immunogenic epitopes as we hypothesized that viral fragments displaying these linear epitopes may be especially abundant in patient samples. By using a nested PCR approach, we successfully identified antibody sequences from single antigen-binding B cells isolated from convalescent COVID-19 patients. Even though we were able to successfully clone and express 20 monoclonal antibodies, ELISA results showed that the antibodies did not bind specifically to our target antigen. Efforts are currently ongoing to troubleshoot, including rectifying mutations which might have arisen during cloning, in order to produce antigen-specific monoclonal antibodies which can then be characterized and potentially used in the production of high sensitivity diagnostic kits.