Working at the interface of biophysics and immunology with strategic applications of the S-RBD from SARS-CoV-2

TOMAS GRAU R; PLOPER D.; NAVARRO S.; AVILA C.; STAGNETTO A; GONZALES LIZARRAGA, MF; SOCIAS SB.; CAZORLA S; MALDONADO C; PERDIGÓN G; APICHELA S; ARGAÑARAZ M; ZAMPINI R; VELEZ E; CHAVES S.; VERA PINGITORE E; LLAPUR C; APFELBAUM G; AGUILAR L; FLORES I; TOLEDO R; COSTA D; CHEHÍN R.

Encuentro; The Young Initiative on Biophysics Talks; 2020

The Young Initiative on Biophysics

COVID-19, the pandemic caused by the SARS-CoV-2 virus, threatens to collapse healthcaresystems around the world. Therefore, the search for strategies capable of counteracting the effectsof this disease is crucial. Taking into account that the receptor binding domain (S-RBD), locatedin the glycoprotein S of the virus surface is crucial for its pathogenesis, and its region is a criticaltarget for neutralizing antibodies, we set out to express and purify the recombinant S-RBD proteinfrom SARS-CoV-2 and use it for the development of local diagnostic methods and researchpurposes.To obtain the S-RBD protein, we generated a stable cell line by transducing HEK293T cells usinga lentivirus system. The correct transduction and expression were assessed by animmunofluorescence. S-RBD was purified by FPLC by affinity purification for it subsequent use in:i) the development of an ELISA test ii) immunization of a llama to obtain nanoantibodies and iii)studying the potential effect of SARS-CoV-2 in neurodegenerative diseases.The continuous production of S-RBD protein was used for the development of a reproducible, lowcost, sensitive and robust serological test that correlates with neutralizing antibodies. We foundthat 25% of patients tested with detectable IgG anti-RBD have a high enough antibody titer (above1/1000) to be considered as plasma donors. In llama, the titers obtained were above 1/80000,suitable to continue the project to purify nanoantibodies. The continuous production of S-RBDprotein also ensure enough reagent to study how SARS-CoV-2 might affect neurodegenerationfrom a biochemical and cell biology perspective.