Monoclonal and Polyclonal Antibodies as Biological Reagents for SARS-CoV-2 Diagnosis Through Nucleocapsid Protein Detection

by Daily Hernández, Cristina García, Marcos González, Hilda Garay, David Diago, Luis Guzmán, Williams Ferro, Mayté Quintana, Leonardo Gómez, Bárbara Chávez, Virginia Capó, Hasel Aragón, Amalia Hernández, Samy Puertas, Pedro Puente, Regla Somoza, Grechen Menéndez, Sigifredo Padilla, Israel Borrajero, and Rodolfo Valdés
Volume 20, Open Access (June 2021)

SARS-CoV-2 is an enveloped, positive-strand RNA virus that contains four structural proteins: spike, envelope, membrane, and nucleocapsid (N-protein). The N-protein participates in virus RNA packaging and particle release, is conserved within SARS-CoV-2 isolates, is highly immunogenic, and is abundantly expressed during SARS-CoV-2 infection. For these reasons, the N-protein could be used as a marker for detecting SARS-CoV-2 in early infection when antibodies against SARS-CoV-2 have not been produced yet. This paper describes the production and characterization of mouse monoclonal antibodies (mAb) and rabbit polyclonal antibodies (pAb) specific for the M20P19 peptide (N-protein linear epitope) for detection purposes. For this study, B-cell hybridomas were generated from mice independently immunized with two different M20P19 peptide-carrier protein conjugates: (1) meningococcal protein P64K; and (2) the keyhole limpet hemocyanin (KLH). Rabbits were also independently immunized with these two immunogens. Study results demonstrated that the M20P19 peptide was very immunogenic in mice and rabbits, and both mAb and pAb specifically recognized the non-conjugated M20P19 peptide, conjugated M20P19 peptide, and N-protein with high affinity and specificity, which could allow SARS-CoV-2 detection by different analytical techniques. This study corroborated that specific and high affinity constant mAb and pAb against the M20P19 peptide can be used as biological reagents for specific and rapid SARS-CoV-2 detection, mainly in tissue samples.

Hern√°ndez D et al. Monoclonal and polyclonal antibodies as biological reagents for SARS-CoV-2 diagnosis through nucleocapsid protein detection. BioProcess J, 2021; 20.

Posted online June 23, 2021.