SARS CoV2 spike receptor binding domain produced in Pichia pastoris and mammalian cells. Uses in diagnosis, in obtaining neutralizing antibodies and as a potential vaccine.

CONSORCIO ARGENTINO ANTI-COVID; NOSEDA DIEGO GABRIEL

Washington

Congreso; Pichia Congress 2021; 2021

At the beginning of the SARS-CoV-2 pandemic we have designed a strong collaborative work among researchers of different institutes in Argentina, taking advantage of each member´s expertise. Our goals were to obtain antigens (proteins and multiprotein complexes) useful for the diagnosis and therapy against COVID19, and to make these developments available to the society in the fastest and most cost-accessible way. In this work we compared the conformation of the receptor binding domain (RBD) from severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Spike protein expressed in the cost-effective and easily scalable system for recombinant protein production P. pastoris and in the well established HEK-293T mammalian cell system. RBD obtained from both yeast and mammalian cells was properly folded, as indicated by UV-absorption, circular dichroism and tryptophan fluorescence. They also had similar stability. Also, we will present the improvements in the design of an antigen with better immunogenic characteristics compared with those of wild type monomeric RBD, obtained through the covalent coupling of RBD with other proteins. Our efforts opened a big window of collaboration with other groups outside of our consortium: the purified proteins were useful for anti SARS-CoV-2 antibody detection, IgY neutralizing antibodies production, vaccine investigations, and monoclonal antibody developments.