Chimeric virus-like particles carrying the CLEC17A carbohydrate-recognition domain significantly reduce Macrobrachium rosenbergii nodavirus infection in Sf9 cells

Abstract

Our previous studies demonstrated that Macrobrachium rosenbergii nodavirus (MrNV) infects and replicates in Sf9 insect cells, where fucosylated N- and O-glycans (HexNAc (Fuc)HexNAc-R or Fuc-LacdiNAc) serve as essential binding molecules for viral attachment. Additionally, we showed that the virus-like particles of the virus itself (MrNV-VLPs) were able to bind to the white-tail disease (WTD)-associated tissues and infect Sf9 cells; and these processes were significantly reduced by removing 27 amino acids from the C-terminus of the protruding (P) domain. In this study, we demonstrated that icosahedral particles could still form following the truncation of the P-domain at sites adjacent to known calcium-binding domains (CBDs) present in the S-shell domain in the MrNV capsid protein. We further showed that icosahedral particles could still form after truncation of the P-domain near calcium-binding sites in the S-domain. This generated smaller but intact particles lacking protrusions, designated V250-MrNV-VLPs. The particles with their intact S-shells enabled our complete replacement of the original MrNV capsid protein P-domains with the fucose-binding carbohydrate-recognition domain (CRD) of CLEC17A lectin (Prolectin), successfully creating CLEC17A/CRD-MrNV-VLPs. The chimeric CLEC17A/CRD-MrNV-VLPs were stable icosahedral particles with P-domains structurally distinct from both the smooth V250-MrNV-VLPs and the blade-like domains of wild-type MrNV-VLPs. Furthermore, the chimeric VLPs presented specific binding activities towards immobilized fucosylated glycoconjugates and Sf9 cell protein lysates. Notably, CLEC17A/CRD-MrNV-VLPs were able to reduce MrNV binding and infection in Sf9 cells. Therefore, this study demonstrated the potential for CLEC17A/CRD-MrNV-VLPs as particles that can effectively bind to fucosylated glycans, and their potential development as nanoparticles that can significantly reduce the level of infection by MrNV in susceptible cells.