Large scale expression of SARS-CoV-2 spike protein antigenic regions to aid development of kits to measure immunity to COVID‑19 disease.
Testing for the presence of the SARS-CoV-2 virus (the causative agent of COVID‑19 disease) and testing for immunity to the virus are critical tools needed to create informed public policy to combat the COVID‑19 pandemic. The SARS-CoV-2 virus has a spike protein on its surface, and antibodies against certain regions of the spike protein are thought to block viral entry into cells, and thus, the presence of such antibodies in an individual indicate immunity to COVID‑19 disease. The critical component of any assay to detect anti-SARS-CoV-2 antibody is recombinant spike protein or recombinant fragments of the spike protein. This proposal describes an approach to generate recombinant SARS-CoV-2 spike protein antibody binding regions at cost that are 100 to 1,000 times lower than the cost of producing spike protein using current methods. Our recombinant system uses the bacterium Bacillus subtilis to secrete recombinant spike protein into the growth medium, which allows a simple separation of the spike protein fragments from the bacterial cells. This recombinant bacterium can be cultivated in industrial size bioreactors using simple, inexpensive growth medium. The production of inexpensive spike protein regions will provide a competitive advantage for our industry partner and will be a useful tool in fighting the COVID‑19 pandemic, especially in resource poor regions of the world.