Anti-sars-cov-2 monoclonal antibodies applied to diagnostic of covid-19.

YANINA HIRIART; GASTÓN ORTIZ; MAIA ELIZAGARAY ; INÉS HARGUINDEGUY; ANDREA CRIVARO; DAVID ROMANIN; MARÍA FLORENCIA CECCACCI; SEBASTIÁN CAVALITTO; GUILLERMO DOCENA; MARTÍN RUMBO

Congreso; REUNIÓN CONJUNTA SAIC SAI&FAIC SAFIS 2022; 2022

The fast spreading of SARS-CoV-2 worldwide evidenced the needfor rapid diagnostic methods. Taking it in account we obtained murine monoclonal antibodies (Mabs) against recombinant nucleocapsid (N) protein of wild type Sars-CoV-2 strain (Wuhan-variant) to beused in immunochemical diagnostic. We selected specific anti-N5E9, 2A4 and 1B9 hybridoma clones. The Mabs were characterized by SPR and showed Kd values of 7.08 nM, 31 nM and 14.8nM respectively. Indirect Immunofluorescense assay on Vero cellsinfected with diferent strains of coronavirus showed that anti-N Mabsrecognized wild type and B.1.617.2 (Delta) and Omicron variants.The 59-peptide array spanning the nucleocapsid (N) protein of theUSA-WA1/2020 strain from bei RESOURCES was used for epitopemapping by competitive ELISA. All Mabs recognized a single peptide each. With the aim of developing a rapid antigen test using lateral flow technology, one Mab was selected and policlonal antibodiesagainst N protein were obtained from chicken. The lateral flow testwas validated comparing the results obtained by PCR in 233 nasopharyngeal swabs and its sensitivity and specificity were 82.6%and 90.7%, respectively. In conclusion, we established a valid rapidantigen test that allows the detection of most relevant SARS-CoV-2variants for COVID-19 diagnostic. This offer laboratory-independentresults at the point of care in a cheaper and faster way than PCR.