Development of porcine monoclonal antibodies with in vitro neutralizing activity against classical swine fever virus from C-strain E2-specific single B cells

Authors: WANG, LIHUA - Kansas State University; MADERA, RACHEL - Kansas State University; LI, YUZHEN - Kansas State University; Gladue, Douglas; Borca, Manuel; MCINTOSH, MICHAEL - University Of Florida; SHI, JISHU - Kansas State University

Submitted to: Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2023
Publication Date: 3/28/2023
Citation: Wang, L., Madera, R., Li, Y., Gladue, D.P., Borca, M.V., Mcintosh, M., Shi, J. 2023. Development of porcine monoclonal antibodies with in vitro neutralizing activity against classical swine fever virus from C-strain E2-specific single B cells. Viruses. 15(4). Article 863. https://doi.org/10.3390/v15040863.
DOI: https://doi.org/10.3390/v15040863

Interpretive Summary: Classical swine fever (CSF) is a disease caused by CFV virus (CSFV) that causes lethal disease in swine. One aspect in preventing disease is understanding the immune response and neutralization antibody production. In this study, we generated three porcine monoclonal antibodies (mAbs) with neutralizing activity against CSFV. The generated natural porcine Abs can be used to develop long-acting and low immunogenicity passive antibody vaccine or anti-CSFV agents for CSF control and prevention.

Technical Abstract: Neutralizing antibodies (nAbs) can be used before or after infection to prevent or treat viral diseases. However, there are few efficacious nAbs against classical swine fever virus (CSFV) that have been produced, especially the porcine originated nAbs. In this study, we generated three porcine monoclonal antibodies (mAbs) with neutralizing activity against CSFV, aiming to facilitate the development of passive antibody vaccines or antiviral drugs against CSFV that offer the advantages of stability and low immunogenicity. Pigs were immunized with C-strain E2 (CE2) subunit vaccine, KNB-E2. At 42 days post vaccination (DPV), CE2 specific single B cells were isolated via fluorescent-activated cell sorting (FACS) baited by Alexa Fluor™ 647 labeled CE2 (positive), Goat Anti-Porcine IgG (H+L)-FITC antibody (positive), PE Mouse Anti-Pig CD3e (negative) and PE Mouse Anti-pig CD8a (negative). The full coding region of IgG heavy (H) chains and light (L) chains were amplified by reverse transcription-polymerase chain reaction (RT-PCR). Overall, we obtained 3 IgG H chains, 9 kappa L chains and 36 lambda L chains, which include three paired chains (two H+ kappa and one H+ lambda). CE2 specific mAbs were successfully expressed in 293T cells with the three paired chains. The mAbs can potently neutralize CSFVs (100% inhibition with collected culture supernatant can reach 1:40 to 1:80 dilution). This study is the first report to describe the amplification of whole-porcine IgG genes from single B cells of KNB-E2 vaccinated pig. The method is versatile, sensitive, and reliable. The generated natural porcine nAbs can be used to develop long-acting and low immunogenicity passive antibody vaccine or anti-CSFV agents for CSF control and prevention.