It may seem self-evident that a crucial reagent in the study of COVID-19 is the virus (SARS-CoV-2) itself, however, producing live coronavirus in large quantities is actually easier said than done. The best solution for these problems is to reconstitute live virus from recombinant vectors using reverse genetics approaches. More specifically, vectors in the form of double-stranded DNA that carry the coronavirus genome of interest can be constructed, then transfected into packaging cells to produce large quantities of live virus. Such vectors can be further modified easily with desired changes such as adding reporter genes (e.g. EGFP) or introducing specific mutations. Additionally, given that coronavirus has a positive-sense, single-stranded RNA genome, the DNA-based viral vectors are not infectious themselves and are therefore very safe to handle and ship with minimal biosafety requirements.
The coronavirus vector system we provided allows users to reconstitute live virus of any coronavirus species – wildtype or mutated version – by simply transfecting our vector into the proper packaging cells. The resulting virus can be further propagated and amplified to any quantity in the appropriate cell line.