Conclusions
In this work, we show that SARS-CoV-2 recombinant S protein could be
produced inexpensively after infection of R. nu larvae and easily
purified later after a single chromatographic step. Noteworthy, the
antigenic properties of this large, complex, highly glycosylated protein
are retained, as evidenced during its application for developing a
serologic ELISA test. One gram of insect larvae produces an amount of S protein
sufficient for 150 determinations in the ELISA method. The scale-up of S
protein production is linear in this biotechnological platform, avoiding
the use of complex equipment like bioreactors. Thus, it is
straightforward to conclude that our approach represents a rapid, easy,
and cost-effective method for the production of recombinant S for
diagnostic applications. We expect that our approach will bring new
tools for serologic test producers to face the unprecedented demand for
these products during the current COVID 19 pandemic.