High-throughput isolation of SARS-CoV-2 nucleocapsid antibodies for improved antigen detection

• Published in: Biochemical and biophysical research communications Vol. 673; pp. 114 - 120
• Main Authors: Fujisawa, Mizuki, Adachi, Yu, Onodera, Taishi, Shiwa-Sudo, Nozomi, Iwata-Yoshikawa, Naoko, Nagata, Noriyo, Suzuki, Tadaki, Takeoka, Shinji, Takahashi, Yoshimasa
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 17.09.2023
• Subjects: Antigen test; COVID-19; Nucleocapsid protein; SARS-CoV-2; Single B-cell culture; COVID-19; Antigen test; SARS-CoV-2; Single B-cell culture; Nucleocapsid protein
• ISSN: 0006-291X; 1090-2104; 1090-2104
• DOI: 10.1016/j.bbrc.2023.06.067

SARS-CoV-2 nucleocapsid protein (NP) is the main target for COVID-19-diagnostic PCR and antigen rapid diagnostic tests (Ag-RDTs). Ag-RDTs are more convenient than PCR tests for point-of-care testing or self-testing to identify the SARS-CoV-2 antigen. The sensitivity and specificity of this method depends mainly on the affinity and specificity of NP-binding antibodies; therefore, antigen-antibody binding is key elements for the Ag-RDTs. Here, we applied the high-throughput antibody isolation platform that has been utilized to isolate therapeutic antibodies against rare epitopes. Two NP antibodies were identified to recognize non-overlapping epitopes with high affinity. One antibody specifically binds to SARS-CoV-2 NP, and the other rapidly and tightly binds to SARS-CoV-2 NP with cross-reactivity to SARS-CoV NP. Furthermore, these antibodies were compatible with a sandwich enzyme-linked immunosorbent assay that exhibited enhanced sensitivity for NP detection compared to the previously isolated NP antibodies. Thus, the NP antibody pair is applicable to more sensitive and specific Ag-RDTs, highlighting the utility of a high-throughput antibody isolation platform for diagnostics development. •Antigen-rapid diagnostic tests (Ag-RDTs) are effective in screening for COVID-19 infection especially fast point-of-care diagnostics.•A high-throughput antibody isolation platform was applied to develop new antibody pair against SARS-CoV-2 nucleocapsid protein.•The utility of the antibody pair allowed us to detect virus protein with high sensitivity and specificity.