Title : Two Residues in VP2 Contribute to the Enhanced Replication and Pathogenicity of Raccoon dog Parvovirus
Abstract:
Raccoon dog parvovirus (RDPV) is a highly contagious viral pathogen that causes acute and often fatal hemorrhagic enteritis, particularly in young raccoon dogs. Since 2016, epidemiological studies have reported frequent outbreaks of RDPV with increased virulence, yet the molecular mechanisms behind this heightened pathogenicity remain elusive. In our study, an alignment of all available full-length sequences of RDPV (n=38) revealed two consistent amino acid mutations that differed between RDPV before and after the 2016 outbreak were located at positions 27 and 297 in capsid protein VP2. Next, a series of mutant viruses with either single or double amino acid replacements were generated from RDPV 2016 strains and RDPV 2010 strains infectious cDNA clones. Deletion of either of the amino acids led to a great impact of virus viability. In F81 cells, we observed that mutant viruses derived from RDPV 2016 showed reduced replication efficiency and attachment compared to the parental strain. Conversely, mutant viruses derived from RDPV-10 exhibited enhanced replication and attachment. Plaque growth assays showed clear differences between mutant and parental viruses. ELISA and BLI (Biofilm interferometry) assays demonstrated a significant reduction in transferrin receptor (TfR) binding by RDPV 2016 derived mutants. In infected racoon dogs, the pathogenicity of RDPV 2016 derived mutant viruses, assessed through clinical symptoms, viral load in sera and anal swabs, histopathology examination was reduced. Our results indicate that the amino acids at positions 27 and 297 in VP2 are involved in the replication ef?ciency of RDPV 2016 and contribute to enhanced pathogenicity. This study is the ?rst to identify speci?c amino acids involved in RDPV replication or pathogenicity. These ?ndings will contribute to understanding the molecular mechanisms of RDPV replication and pathogenicity, leading to better therapeutic and prognostic options to combat the virus.
Audience Take Away:
- This study providing insights into the molecular mechanisms underlying RDPV infection, which could inform the development of more effective therapeutic and prognostic strategies against the virus.
