Porcine epidemic diarrhea virus (PEDV) is a highly infectious pathogen that can cause severe diseases in pigs and result in enormous economic losses in the worldwide swine industry. Previous studies revealed that PEDV exhibits an obvious capacity for modulating interferon (IFN) signaling or expression. The newly discovered type III IFN, which plays a crucial role in antiviral immunity, has strong antiviral activity against PEDV proliferation in IPEC-J2 cells. In this study, we aimed to investigate the effect of PEDV nucleocapsid (N) protein on type III IFN-λ. We found that the N proteins of ten PEDV strains isolated between 2013 and 2017 from different local farms shared high nucleotide identities, while the N protein of the CV777 vaccine strain formed a monophyletic branch in the phylogenetic tree. The N protein of the epidemic strain could antagonize type III IFN, but not type I or type II IFN expression induced by polyinosinic-polycytidylic acid (poly(I:C)) in IPEC-J2 cells. Subsequently, we demonstrated that the inhibition of poly(I:C)-induced IFN-λ3 production by PEDV N protein was dependent on the blocking of nuclear factor-κB (NF-κB) nuclear translocation. These findings might help increase understanding of the pathogenesis of PEDV and its mechanisms for evading the host immune response.
Active Transport, Cell Nucleus ; Animals ; Coronavirus Infections ; immunology ; veterinary ; virology ; Genes, Viral ; Host-Pathogen Interactions ; immunology ; Interferons ; antagonists & inhibitors ; biosynthesis ; genetics ; Interleukins ; antagonists & inhibitors ; biosynthesis ; genetics ; NF-kappa B ; metabolism ; Nucleocapsid Proteins ; genetics ; immunology ; physiology ; Porcine epidemic diarrhea virus ; genetics ; pathogenicity ; physiology ; Promoter Regions, Genetic ; Swine ; Swine Diseases ; immunology ; virology

The deltacoronavirus is a new member of the subfamily Coronaviridae of the family Coronaviridae. Deltacoronaviruses can infect birds and mammals. Deltacoronaviruses were detected in early 2007 in Asian leopard cats and Chinese ferret badgers. In 2014, porcine deltacoronavirus (PDCoV) infection spread rapidly in the USA. Moreover, cell culture-adapted PDCoV has been obtained from infected piglets. Animal experiments have confirmed that the isolated PDCoV is highly pathogenic and causes severe diarrhea in piglets. Thus, the PDCoV can be considered to be a good model to study the deltacoronavirus. In this review, we discuss the etiology, epidemiology, pathogenicity, culture, and diagnostic methods of the PDCoV.
Animals ; Coronavirus ; classification ; genetics ; isolation & purification ; Coronavirus Infections ; veterinary ; virology ; Diarrhea ; veterinary ; virology ; Phylogeny ; Swine ; Swine Diseases ; virology

In July 2009, some farms of breeding Muscovy ducks on the peak of egg laying suffered the decrease of hatching rate and the quality of the eggs showing low mortality and no evident respiratory symptoms. The swelling and congestive ovary was visible after autopsy. This study was brought out for the diagnosis of these cases. The virus was isolated and identified by the methods of virus culture in chicken embryo, physical and chemical properties test, hemagglutinin test, NDV (Newcastle diseases Virus) interference test, electron microscope observation, pathogenicity test and the gene sequence analysis. The results indicated the virus showed the characters of inducing dwarf embryo after inocubation, the sensibility to lipid solvent and the hemagglutination capacity after pancreatic enzyme treatment, the typical morphology of coronavirus, the interference to NDV replication and the homology among 84.7% - 99% of the particial N gene sequences to the reference IBV (Avian infectious bronchitis virus) strains. The strain was identified as IBV isolate and this study confirmed the pathogenicity of IBV to Muscovy ducks.
Amino Acid Sequence ; Animals ; Chick Embryo ; Coronavirus Infections ; veterinary ; virology ; Ducks ; virology ; Female ; Infectious bronchitis virus ; classification ; genetics ; isolation & purification ; Molecular Sequence Data ; Phylogeny ; Poultry Diseases ; virology ; Sequence Alignment

We wished to ascertain the prevalence as well as the genetic and antigenic variation of infectious bronchitis viruses (IBVs) circulating in the Guangxi Province of China in recent years. The S1 gene of 15 IBV field isolates during 2012-2013 underwent analyses in terms of the similarity of amino-acid sequences, creation of phylogenetic trees, recombination, and serologic identification. Similarities in amino-acid sequences among the 15 isolates of the S1 gene were 54.3%-99.6%, and 43.3%-99.3% among 15 isolates and reference strains. Compared with the vaccine strain H120, except for GX-YL130025, the other 14 isolates showed a lower similarity of amino-acid sequences of the S1 gene (65.1-81.4%). Phylogenetic analyses of the S1 gene suggested that 15 IBV isolates were classified into eight genotypes, with the predominant genotype being new-type II. Recombination analyses demonstrated that the S1 gene of the GX-NN130048 isolate originated from recombination events between vaccine strain 4/91 and a LX4-like isolate. Serotyping results suggested that seven serotypes prevailed during 2012-2013 in Guangxi Province, and that only one isolate was consistent with the vaccine strain H120 in serotype (which has been used widely in recent years). The serotype of recombinant isolate GX-NN130048 was different from those of its parent strains. These results suggested that not only the genotype, but also the serotype of IBV field isolates in Guangxi Province had distinct variations, and that increasing numbers of genotypes and serotypes are in circulation. We showed that recombination events can lead to the emergence of new serotypes. Our study provides new evidence for understanding of the molecular mechanisms of IBV variations, and the development of new vaccines against IBVs.
Animals ; Antibodies, Viral ; blood ; Chickens ; China ; Coronavirus Infections ; blood ; veterinary ; virology ; Genetic Variation ; Genotype ; Infectious bronchitis virus ; classification ; genetics ; immunology ; isolation & purification ; Molecular Sequence Data ; Phylogeny ; Poultry Diseases ; blood ; virology ; Sequence Homology, Amino Acid ; Spike Glycoprotein, Coronavirus ; chemistry ; genetics ; immunology

The purpose of this study was to investigate the genetic features of canine coronavirus (CCV) strains detected in Korea. M gene sequences obtained for isolates from 22 dogs with enteritis over a 5-year period were evaluated. Sequence comparison revealed that the 22 Korean CCV strains had an 87.2 to 100% nucleotide homology. Comparing to the typical reference CCV strains (type II), the nucleotide sequence of Korean strains had homology ranged from 86.3% to 98.3% (89.1% to 99.2% for the amino acid sequence) and 87.7% to 97.8% (92.4% to 100% for the amino acid sequence) when compared to FCoV-like CCV strains (type I). Three amino acid variations in the M gene were characteristic for the Korean CCV strains. Phylogenetic analysis demonstrated that the 22 Korean CCV strains belonged to four typical CCV clusters (i.e., a unique Korean CCV cluster, a type II and transmissible gastroenteritis virus cluster, an intermediate cluster between type I and II, and a type I cluster). This study was the first to identify genetic differences of the M gene from Korean CCV strains and provided a platform for molecular identification of different Korean CCV strains.
Amino Acid Sequence ; Animals ; Coronavirus Infections/epidemiology/*veterinary/virology ; Coronavirus, Canine/*isolation & purification ; Dog Diseases/*epidemiology/virology ; Dogs ; Female ; Male ; Molecular Sequence Data ; Phylogeny ; Polymerase Chain Reaction/veterinary ; Republic of Korea/epidemiology ; Reverse Transcriptase Polymerase Chain Reaction/veterinary ; Viral Matrix Proteins/*genetics/metabolism

Infectious bronchitis virus (IBV) poses a severe threat to the poultry industry and causes heavy economic losses worldwide. Vaccination is the most effective method of preventing infection and controlling the spread of IBV, but currently available inactivated and attenuated virus vaccines have some disadvantages. We developed a chimeric virus-like particle (VLP)-based candidate vaccine for IBV protection. The chimeric VLP was composed of matrix 1 protein from avian influenza H5N1 virus and a fusion protein neuraminidase (NA)/spike 1 (S1) that was generated by fusing IBV S1 protein to the cytoplasmic and transmembrane domains of NA protein of avian influenza H5N1 virus. The chimeric VLPs elicited significantly higher S1-specific antibody responses in intramuscularly immunized mice and chickens than inactivated IBV viruses. Furthermore, the chimeric VLPs induced significantly higher neutralization antibody levels than inactivated H120 virus in SPF chickens. Finally, the chimeric VLPs induced significantly higher IL-4 production in mice. These results demonstrate that chimeric VLPs have the potential for use in vaccines against IBV infection.
Animals ; Antibodies, Viral/blood ; *Chickens ; Chimera/genetics/immunology ; Coronavirus Infections/prevention & control/*veterinary/virology ; Female ; *Immunity, Innate ; Infectious bronchitis virus/genetics/*immunology ; Influenza A Virus, H5N1 Subtype/genetics/immunology ; Injections, Intramuscular/veterinary ; Mice ; Mice, Inbred BALB C ; Neuraminidase/genetics ; Poultry Diseases/*prevention & control/virology ; Recombinant Fusion Proteins/genetics/immunology ; Spike Glycoprotein, Coronavirus/genetics/*immunology ; Vaccines, Synthetic/administration & dosage/genetics/immunology ; Vaccines, Virus-Like Particle/administration & dosage/genetics/*immunology ; Viral Proteins/genetics

To explore the expression potential of heterogeneous genes using the backbone of infectious bronchitis virus (IBV) Beaudette strain, the ectodomain region of the Spike gene (1,302 bp) of IBV H120 strain was amplified by RT-PCR and replaced into the corresponding location of the IBV Beaudette strain full-length cDNA. This recombinant was designated as BeauR-H120(S1). BeauR-H120(S1) was directly used as the DNA template for the transcription of viral genomic RNA in vitro. Then, the transcription product was transfected into Vero cells by electroporation. At 48 h post-transfection, the transfected Vero cells were harvested, and passaging continued. A syncytium was not observed until the recombinant virus had passed through four passages. The presence of rBeau-H120(S1) was verified by the detection of the replaced ectodomain region of the H120 Spike gene using RT-PCR. Western blot analysis of rBeau-H120 (S1)-infected Vero cell lysates demonstrated that the nucleocapsid (N) protein was expressed, which implied that rBeau-H120(S1) could propagate in Vero cells. The TCIDs0 and EIDs0 data demonstrated that the titer levels of rBeau-H120(S1) reached 10(590+/-0.22)TCID50/mL and 10(6.13+/-0.23)EID50/mL in Vero cells and 9-day-old SPF chicken embryos, respectively. Protection studies showed that the percentage of antibody-positive chickens, which were vaccinated with rBeau-H120(S1) at 7 days after hatching, rose to 90% at 21 days post-inoculation. Inoculation provided an 85% rate of immune protection against a challenge of the virulent IBV M41 strain (103EID50/chicken). This recombinant virus constructed using reverse genetic techniques could be further developed as a novel genetic engineering vaccine against infectious bronchitis.
Animals ; Cercopithecus aethiops ; Chick Embryo ; Chickens ; Coronavirus Infections ; veterinary ; virology ; Infectious bronchitis virus ; chemistry ; genetics ; growth & development ; metabolism ; Poultry Diseases ; virology ; Protein Structure, Tertiary ; Spike Glycoprotein, Coronavirus ; chemistry ; genetics ; metabolism ; Transfection ; Vero Cells

This study aimed to understand the dynamic distribution of infectious bronchitis virus (IBV) Jin-13 strain in SPF chickens. Ninety-day-old SPF chickens were inoculated with Jin-13, a virulent strain, and dissected at day 1, 4, 7, 10, 14, 21, 28 or 35 post-inoculation (dpi). Samples of heart, liver, spleen, lung, trachea, kidney and duodenum were collected and the N gene was detected by Sybr Green I real-time quantitative RT-PCR assays. The established method had a good linear correlation from 7.77 x 10(8) to 10(0) copies/microL. SPF chickens developed typical clinical signs of IBV at the 4th dpi, and the IBV viral concentration of tissues and organs gradually increased with a peak of up to 7.13 x 10(4) copies/microL. The viral concentration of most organs decreased by the 10th dpi, but those of the kidney, trachea and lung remained positive for IBV at 28 dpi and the heart was still positive for IBV at > 35 dpi. The results of this study, showed that the Jin-13 strain can cause prolonged virus excertion in chickens with severe renal damage.
Animals ; Chickens ; Coronavirus Infections ; veterinary ; virology ; Infectious bronchitis virus ; isolation & purification ; pathogenicity ; physiology ; Lung ; virology ; Poultry Diseases ; virology ; Reverse Transcriptase Polymerase Chain Reaction ; Specific Pathogen-Free Organisms ; Trachea ; virology ; Virulence

The genome of CK/CH/SD09/005, an isolate of infectious bronchitis virus (IBV), was characterized to enable the further understanding of the epidemiology and evolution of IBV in China. Twenty-five pairs of primers were designed to amplify the full-length genome of CK/CH/SD09/005. The nucleotide sequence of CK/CH/SD09/005 was compared with reference IBV strains retrieved from GenBank. The phylogenic relationship between CK/CH/SD09/005 and the reference strains was analyzed based on S1 gene sequences. The complete genome of CK/CH/SD09/005 consisted of 27691 nucleotides (nt), excluding the 5' cap and 3' poly A tail. The whole-genome of CK/CH/SD09/005 shared 97 - 99% nucleotide sequence homology with the GX-NN09032 strain, which was the only complete genome that was closely related to CK/CH/SD09/005. When compared with all reference strains except GX-NN09032, CK/CH/SD09/005 showed the highest similarity to ck/CH/LDL/091022 and SDIB821/2012 (QX-like) in the replicase gene (Gene 1) and 3'UTR, with a sequence identity rate of 97% and 98%, respectively. However, CK/CH/SD09/005 exhibited lower levels of similarity with ck/CH/LDL/091022 and SDIB821/2012 in S-3a-3b-3c/ E-M-5a-5b-N with a sequence identity of 72% - 90%. CK/CH/SD09/005 showed the highest level of nucleotide identity with Korean strain 1011, and Chinese strains CK/CH/LXJ/02I, DK/CH/HN/ZZ2004 and YX10, in ORF 3c/E (97%), 5a (96%), 5b (99%) and N (96%), respectively. ORFs 3a, 3b and M of CK/CH/SD09/005 exhibited no more than 90% homology with the reference strains, excluding GX-NN09032. The phylogenic analysis based on the S1 gene revealed that CK/CH/SD09/005 and 39 published strains were classified into seven clades (genotypes). CK/CH/SD09/005 was distributed in clade IV with several isolates collected between 2007 and 2012. CK/CH/SD09/005 showed 66% - 69% and 72% - 81% nucleotide identities with the IBV strains of other six clades in the S1 and S2 subunits, respectively. More over, multiple substitutions were found throughout the entire S gene of CK/CH/SD09/005, while insertions and deletions were located within the S1 gene. These results indicated that CK/CH/SD09/005 is a novel variant that may be derived from the QX-like strains that are prevalent in China. Multiple genetic mechanisms, including recombinations, mutations, insertions and deletions, are likely to have contributed to the emergence of this IBV strain.
Animals ; Chickens ; China ; Coronavirus Infections ; veterinary ; virology ; Genome, Viral ; Genomics ; Infectious bronchitis virus ; classification ; genetics ; isolation & purification ; Molecular Sequence Data ; Phylogeny ; Poultry Diseases ; virology ; Sequence Homology, Amino Acid ; Viral Proteins ; chemistry ; genetics

In order to investigate the prevalence and track genetic and antigenic evolutions of infectious bronchitis virus (IBV) and their prevalence in Guangxi, China since 1985, gene amplification and sequencing and virus neutralization (VN) test on chicken embryo tracheal organ cultures were used in genotyping and serotyping of 28 IBV isolates during 2009-2011 in Guangxi. The results of N gene sequencing and comparison showed that the 28 isolates and reference strains were classified into three groups, and most isolates belonged to group Ill, while the isolates in 1985-2008 belonged to groups IV and II. The data of VN test indicated that the 28 isolates belonged to 6 serotypes; among them, 71. 4% belonged to serotypes 1, 2, and 3, and 11 (39.3%) shared the same serotype with the current vaccine strains. Given the data of our previous study, it is found that prevalent serotypes and their proportions varied in different areas of Guangxi and during different periods. These data lay a good foundation for developing an oil-emulsified inactivated polyvalent vaccine containing local dominant serotypes for the effective prevention and control of infectious bronchitis.
Animals ; Antibodies, Viral ; immunology ; Chick Embryo ; Chickens ; China ; epidemiology ; Coronavirus Infections ; epidemiology ; immunology ; veterinary ; virology ; Infectious bronchitis virus ; classification ; genetics ; immunology ; isolation & purification ; Molecular Sequence Data ; Phylogeny ; Poultry Diseases ; epidemiology ; immunology ; virology