The LORF5 Gene Is Non-essential for Replication but Important for Duck Plague Virus Cell-to-Cell Spread Efficiently in Host Cells

Abstract

Duck plague virus (DPV) can cause high morbidity and mortality in many waterfowl species within the order Anseriformes. The DPV genome contains 78 open reading frames (ORFs), among which the LORF2, LORF3, LORF4, LORF5, and SORF3 genes are unique genes of avian herpesvirus. In this study, to investigate the role of this unique LORF5 gene in DPV proliferation, we generated a recombinant virus that lacks the LORF5 gene by a two-step red recombination system, which cloned the DPV Chinese virulent strain (DPV CHv) genome into a bacterial artificial chromosome (DPV CHv-BAC); the proliferation law of LORF5-deleted mutant virus on DEF cells and the effect of LORF5 gene on the life cycle stages of DPV compared with the parent strain were tested. Our data revealed that the LORF5 gene contributes to the cell-to-cell transmission of DPV but is not relevant to virus invasion, replication, assembly, and release formation. Taken together, this study sheds light on the role of the avian herpesvirus-specific gene LORF5 in the DPV proliferation life cycle. These findings lay the foundation for in-depth functional studies of the LORF5 gene in DPV or other avian herpesviruses.

Characterization of a Unique Novel LORF3 Protein of Duck Plague Virus and Its Potential Pathogenesis

“…Replication properties of recombinant viruses were assessed by multistep growth kinetics as described previously ( 15 , 31 ). Briefly, DEF cells in 24-well plates were infected with an MOI of 0.01 of indicated viruses; samples were collected at 12, 24, 48, 72, and 96 h postinfection (hpi) and stored at −80°C.…”

“…The LORF5 gene-deleted MDV significantly reduces the lethality of chickens and does not induce tumor lesions in chickens. In the duck plague virus, the LORF5 gene is closely related to the cell-to-cell transmission and replication of the virus ( 14 , 15 ). The RLORF2 gene encodes a viral CXC chemokine called vIL-8, and studies have shown that MDV vIL-8 deletion mutants are significantly less virulent and provide effective protection against highly virulent strains in susceptible chickens ( 16 , 17 ).…”

Pathogenicity and transmissibility studies on live attenuated duck enteritis virus vaccine in non-target species

“…Despite substantial effortsto control virus transmission, DEV has continued to infect and spread, indicating that the threat they pose to both domestic poultry and public health has not diminished. To date, DEV has been reported in France, the United States, Canada, and other countries successively, and it has resulted in significant economic losses in modern farming ( Hall and Simmons, 1972 ; Hanson and Willis, 1976 ; Zhang et al, 2020 ; Chen et al, 2021 ; Islam et al, 2021 ; Shen et al, 2021 ). In China, thousands of ducks are reared annually in open fields, with no biosecurity measures in place.…”