Antibody Screening Results for Anti-Nucleocapsid Antibodies Towards the Development of a SARS-CoV-2 Nucleocapsid Protein Antigen Detecting Lateral Flow Assay

The global COVID-19 pandemic has created an urgent demand for accurate rapid point of care diagnostic tests. Antigen-based assays are suitably inexpensive and can be rapidly mass-produced, but sufficiently accurate performance requires highly-optimized antibodies and assay conditions. An automated liquid handling system, customized to handle lateral flow immunoassay (LFA) arrays, was used for high-throughput antibody screening of anti-nucleocapsid antibodies that will perform optimally on an LFA. Six hundred seventy-three anti-nucleocapsid antibody pairs were tested as both capture and detection reagents with the goal of finding those pairs that have the greatest affinity for unique epitopes of the nucleocapsid protein of SARS-CoV-2 while also performing optimally in an LFA format. In contrast to traditional antibody screening methods (e.g. ELISA, bio-layer interferometry), the methods described here integrate real-time LFA reaction kinetics and binding directly on nitrocellulose. We have identified several candidate antibody pairs that are suitable for further development of an LFA for SARS-CoV-2.