Title : Purification process development of COVID antigens to identify sera needed for plasma therapy
One of the crucial steps in deploying plasma therapy for COVID-19 has been the development of critical assays to detect SARS-CoV-2 antibodies and evaluate their potential suitability. Unfortunately, assays that assess neutralizing antibodies involve use of live SARS-CoV-2 virus in a high containment facility (BSL3) which can take up to a week to complete. The assay cost, time for completion, and requirement for PPE make it a weak link in the pipeline for the rapid identification of plasma donors. Also, the commercial assays lack the precise quantitation of protective antibody levels desired in sourcing plasma. Therefore, the goal of the project was to rapidly biomanufacture purified COVID antigens for scaling up a quantitative ELISA assay for characterizing plasma needed for treatment and prophylaxis. In this project, we developed purification processes to generate high quality purified SARS-CoV spike (S)protein and the SARS-CoV-2 S protein receptor binding domain (S-RBD) to be incorporated into these quantitative ELISA assay. The presence of an extremely sensitive and robust assay technique using multiple antigens helped specify the highest binding and protective antibodies (and their targets) from a pool of volunteers and recipients. This presentation will focus on the purification process development of Spike and Spike-RBD antigens as well as other COVID variant antigens and how the workflow helped understand the intricacies of the human immune response after vaccination.