Development of an antigen capture ELISA for detection of SARS-CoV-2

Abstract

Background. In December 2019, the World Health Organization (WHO) declared COVID-19 a global pandemic causing over 700 million cases and more than 7 million deaths globally. In Uganda, over 40,408 cases with 334 deaths were recorded. While rt-PCR remains the gold standard for SARS-CoV-2 diagnosis, it has several limitations which underscore the need for rapid, accurate diagnostic methods. Antigen capture ELISA offers an alternative for use in resource limited settings. This ELISA would be a useful tool for timely diagnosis, contributing to effective public health responses by offering batch-testing for large numbers of samples and providing critical insights into viral transmission and dynamics in the population. Results: Attempts to develop the protocol resulted in erratic inconsistent and lower OD valves which were irreproducible. Despite the titration of anti-SARS-CoV-2 Spike protein IgG (RBD) antigen capture Mab, SARS-CoV-2 antigen, Anti SARS-CoV-2 spike protein IgG-HRP conjugate and different other conditions during the experiment. Conclusion: we failed to achieve our objective due to poor quality or degradation of the SARS-CoV-2 Spike RBD antigen, likely affected its ability to bind effectively to the capture antibody. Additionally, potential issues with the capture antibody's specificity or compatibility with the antigen further weakened the assay's performance. These factors underscore the importance of rigorous quality control and thorough testing of antibody-antigen interactions during the development of ELISA protocols.