AUTHOR=Li Jinxin , Liu Fengli , Ren Zhihao , Fu Guanghua , Shi Jizhen , Zhao Naiyu , Huang Yu , Su Jingliang 

TITLE=Generation of a monoclonal antibody against duck circovirus capsid protein and its potential application for native viral antigen detection

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1206038

DOI=10.3389/fmicb.2023.1206038

ISSN=1664-302X

ABSTRACT=Duck circovirus (DuCV) infection is currently recognized as an important immunosuppressive disease in commercial duck flocks in China. Specific antibodies against DuCV viral proteins are required to improve diagnostic assays and understand the pathogenesis of DuCV infection. To generate DuCV-specific monoclonal antibodies (mAbs), a recombinant DuCV capsid protein without the first 36 N-terminal amino acids was produced in Escherichia coli. Using the recombinant protein as an immunogen, a mAb was developed that reacted specifically with DuCV capsid protein expressed in E. coli and baculovirus systems. Using homology modeling and recombinant truncated capsid proteins, the antibody binding epitope was mapped within the region of 144IDKDGQIV151, which is solvent-exposed in the virion capsid model structure. To assess the applicability of the mAb to probe the native virus antigen, the murine macrophage cell line RAW267.4 was tested for DuCV replication permissiveness. Immunofluorescence and western blot analysis revealed that the mAb recognized the virus in infected cells and the viral antigen in tissue samples collected from clinically infected ducks. This mAb, combined with the in vitro culturing method, should have widespread applications in diagnosing and investigating DuCV pathogenesis.