To achieve uniform soluble expression of multiple proteins in the same Escherichia coli strain, and simplify the process steps of antigen production in genetic engineering subunit multivalent vaccine, we co-expressed three avian virus proteins including the fowl adenovirus serotype 4 (FAdV-4) Fiber-2 protein, infectious bursal disease virus (IBDV) VP2 protein and egg-drop syndrome virus (EDSV) Fiber protein in E. coli BL21(DE3) cells after optimization of gene codon, promoter, and tandem expression order. The purified proteins were analyzed by Western blotting and agar gel precipitation (AGP). The content of the three proteins were well-proportioned after co-expression and the purity of the purified proteins were more than 80%. Western blotting analysis and AGP experiment results show that all the three co-expression proteins had immunoreactivity and antigenicity. It is the first time to achieve the three different avian virus antigens co-expression and co-purification, which simplified the process of antigen production and laid a foundation for the development of genetic engineering subunit multivalent vaccine.
Animals ; Antigens, Viral/genetics* ; Biological Assay ; Chickens/immunology* ; Escherichia coli/genetics* ; Infectious bursal disease virus/immunology* ; Poultry Diseases ; Vaccines, Synthetic/isolation & purification* ; Viral Structural Proteins/immunology* ; Viral Vaccines/immunology*

Recently, avian viral diseases have become one of the main models to study mechanisms of viral infections and pathogenesis. The study of regulatory relationships and mechanisms between viruses and microRNAs has also become the focus. In this review, we briefly summarize the general situations of microRNAs encoded by avian herpesviruses. Also, we analyze the regulatory relationships between tumorigenicity of avian herpesviruses and microRNAs. Additionally, the possible applications for prevention and treatment of viral diseases (such as infectious bursal disease, avian influenza and avian leucosis) using the regulatory mechanisms of microRNAs are also discussed.
Animals ; Avian Leukosis ; Birds ; virology ; Birnaviridae Infections ; Herpesviridae ; genetics ; Influenza in Birds ; MicroRNAs ; genetics

Infectious bursal disease virus (IBDV) is an important member of the Birnaviridae family. IBUV mainly targets the bursa of Fabricius, the central immune organ of chicken, resulting in chicken infectious bursal disease (IBD). IBD represents one of the great challenges for ongoing development of the poultry industry. Reverse genetics for IBDV emerged over twenty years ago. Since then, the technologies behind virus rescue have continually improved leading to a deep understanding of IBDV gene function and tailored vaccine development. Our lab has also been instrumental in the field of IBDV research. Here we review studies on the pathogenic mechanism and the effective prevention and control of IBD.
Animals ; Birnaviridae Infections ; virology ; Chickens ; Infectious bursal disease virus ; genetics ; physiology ; Poultry Products ; virology ; Reverse Genetics

In order to determine immunogenicity and protective effect in chickens, we used the IBDV (Infectious bursal disease virus)-Vp2/Lactobacillus casei as antigen transfer system. First, the immunized and control chickens were challenged by IBDV/DQ at lethal dose to determine the protective ratio. Second, chickens were orallyand intranasally vaccinated twice with 10(9) CFU/mL pLA-VP2/L. casei, pLA/L. casei and PBS as negativecontrol and commercial vaccine as positive control. The bursa injury and the lesion score wererecorded post challenge. The level of specific IgG and sIgA in pLA-VP2/L. casei and positive control groups was significantly higher than that in negativecontrol groups. The protection efficacy in pLA-VP2/L. casei oral group was higher than that inintranasal group. The SI. of pLA-VP2/L. casei oral group was significant higher than other groups. The lesion score indicated the pLA-VP2/L. casei was safer than commercial vaccine for bursa. Collectively, the pLA-VP2/L. casei could be a vaccine candidate for IBDV.
Animals ; Antibodies, Viral ; blood ; Antibody Formation ; Birnaviridae Infections ; prevention & control ; veterinary ; Chickens ; Infectious bursal disease virus ; Lactobacillus casei ; Poultry Diseases ; prevention & control ; Recombinant Proteins ; immunology ; Viral Structural Proteins ; immunology ; Viral Vaccines ; immunology

Infectious bursal disease virus (IBDV) VP4 plays an important role in immunosuppression of host. In order to develop monoclonal antibodies (McAbs) against VP4, we vaccinated BALB/c mice with His-VP4, screened and subcloned positive clones. We established 4 hybridoma cell lines that stably secreted McAbs against VP4 and named these cell lines 3B3, 3H11, 4C8 and 4G6, respectively. We tested the dissociation constant (Kd) of these McAbs, and found that their K(d)s were 4.61 x 10(-11), 1.71 x 10(-10), 4.26 x 10(-11), 5.02 x 10(-11), respectively. The isotypes of these McAbs were determined to be IgG1, IgG1, IgG2b and IgG1. These McAbs specifically bound to VP4 in IBDV infected DF-1 cells as demonstrated by Western blotting analysis and fluorescence antibody assay. These McAbs would help to detect IBDV infection and to analyze the biological activities of IBDV VP4.
Animals ; Antibodies, Monoclonal ; biosynthesis ; Blotting, Western ; Cell Line ; Fluorescent Antibody Technique ; Hybridomas ; Infectious bursal disease virus ; Mice ; Mice, Inbred BALB C ; Viral Structural Proteins ; immunology

To evaluate the immunities of biodegradable microsphere as a release delivery system for DNA vaccine against Infectious Bursal Disease Virus, in our study, silk fibroin/chitosan microsphere adjuvant was prepared with a precipitation/coacervation method. Both glutaraldehyde and Na2SO4 solution were used in cross-linking. No immune chicken were intramuscularly inoculated at 14 day-old and boosted 2 weeks later. The results show that glutaraldehyde destroyed the DNA activity of the vaccine whereas Na2SO4 solution did not. Factors of the chitosan concentration 0.5% (pH 5.0), silk fibroin concentration 0.6%, plasmid DNA (500 microg/mL) dissolved in 2% Na2SO4 solution were optimized to produce microsphere, with a loading capacity of 89.14%. The average particle size of SF-CS/pCI-VP2/4/3 microsphere is 1.98 microm, and it can protect the loading DNA vaccine from DNase I digestion. Data from anti IBDV ELISA antibodies in the serum show that immunization activity of the microsphere groups were generally higher than plasmid vaccine group (P < 0.05), and the SF/CS compound microspheres group was better than that of sole CS microsphere group. The developed SF/CS microspheres are a very promising vaccine delivery system.
Adjuvants, Immunologic ; chemistry ; Animals ; Birnaviridae Infections ; prevention & control ; veterinary ; Chickens ; Chitosan ; chemistry ; Fibroins ; chemistry ; Infectious bursal disease virus ; Microspheres ; Plasmids ; Poultry Diseases ; prevention & control ; Vaccines, DNA ; chemistry ; Viral Vaccines ; chemistry

To meet the needs of detection of infectious bursal disease virus (IBDV) under high efficient culture, a SYBR Green I real-time RT-PCR (qRT-PCR) was developed using a pair of primers specific to the conserved region of VP4 gene of IBDV and compared with TCID50 method by monitoring the proliferation dynamics of IBDV in DF-1 cell line adherent to micro carrier in tubular reactor. The results showed that the RT-PCRassay was linear in the range of 4. 03 X 10(1)-10(9) copies/microL. The IBDV RNA detection limit was 40 copies/microL, which was 1 000 times more sensitive than conventional PCR. No cross-reactions with other viruses was observed. The intra-assay coefficient of variation was less than 0.05%. There was a parallel correlation of IBDV proliferation dynamics in DF-1 cell under Micro carrier suspension and static adherent culture by the qRT-PCR assay and TCID50 method. The detection results of the IBDV samples from tubular and flask culture showed the differences of the micro carrier and adherent culture by both methods. In conclusion, the qRT-PCR assay is more rapid and sensitive than the TCID50 method, which is more appropriate for the real time detection of IBDV.
Animals ; Calibration ; Cell Line ; Conserved Sequence ; DNA Primers ; genetics ; Infectious bursal disease virus ; genetics ; isolation & purification ; Organic Chemicals ; chemistry ; metabolism ; Real-Time Polymerase Chain Reaction ; methods ; Reproducibility of Results ; Spectrometry, Fluorescence ; Viral Proteins ; genetics ; Virus Replication

A recombinant modified vaccinia Ankara (MVA) virus expressing mature viral protein 2 (VP2) of the infectious bursal disease virus (IBDV) was constructed to develop MVA-based vaccines for poultry. We demonstrated that this recombinant virus was able to induce a specific immune response by observing the production of anti-IBDV-seroneutralizing antibodies in specific pathogen-free chickens. Besides, as the epitopes of VP2 responsible to induce IBDV-neutralizing antibodies are discontinuous, our results suggest that VP2 protein expressed from MVA-VP2 maintained the correct conformational structure. To our knowledge, this is the first report on the usefulness of MVA-based vectors for developing recombinant vaccines for poultry.
Animals ; Antibodies, Viral ; Birnaviridae Infections/prevention & control/*veterinary ; Cells, Cultured ; Chick Embryo ; Chickens ; Fibroblasts/metabolism ; Infectious bursal disease virus/*immunology ; Poultry Diseases/*prevention & control/virology ; Specific Pathogen-Free Organisms ; Vaccinia virus/*genetics/immunology/metabolism ; Viral Structural Proteins/genetics/*immunology/metabolism ; Viral Vaccines/*immunology

Two Bangladeshi infectious bursal disease virus (IBDV) isolates collected in 2007, termed GB1 and GB3, were subjected to comparative sequencing and phylogenetic analyses. Sequence analysis of a 474-bp hypervariable region in the VP2 gene revealed that among four major amino acid substitutions observed in the strains, two were unique to GB1 and GB3 (Ser217Leu and Ala270Thr) while one substitution was only found in GB1 (Asn299Ser). Among IBDVs from Bangladesh including GB1 and GB3, the rate of identity and homology was around 97~99%. The amino acid sequences of GB1 and GB3 differ from those of previous Bangladeshi IBDV isolates and contain amino acid substitutions Pro222Ala and Asn299Ser (in GB3 only). Phylogenetic analysis revealed that GB1 and GB3 are grouped with other very virulent IBDVs of European and American origin in contrast to two previously isolated Bangladeshi IBDV strains (GenBank accession Nos. AF362776 and AF260317), which belong to the Asian group. It was concluded that GB1 and GB3 belong to a very virulent group of IBDVs. However, amino acid sequences of GB1 and GB3 differ from those of the other Bangladeshi IBDVs by one or two amino acids encoded in the hypervariable region of the VP2 gene.
Amino Acid Sequence ; Amino Acid Substitution ; Amino Acids ; Asian Continental Ancestry Group ; Bangladesh ; Chickens ; Genetic Markers ; Humans ; Infectious bursal disease virus ; Sequence Analysis

Infectious bursal disease virus (IBDV) is a member of the Avibirnavirus genus of the Birnaviridae family which genome consists of two segments (A and B) of double stranded RNA. Segment A gene of KNU08010 isolate, which was isolated from a 15-day-old chicken flock in 2008, was sequenced and compared with other IBDV isolates including SH/92 strain, the first Korean very virulent (vv) IBDV isolate. The amino acid sequences of segment A gene showed that KNU08010 had 99.2% homology with SH92 strain. KNU08010 isolate had specific amino acids A222, I242, I256, I294 and S299 which are highly conserved among vvIBDV strains. Phylogenetic analysis based on the nucleotide sequences of variable region of the VP2 gene of 18 IBDV strains revealed that KNU08010 was grouped with vvIBDVs and was closely related to Korean vvIBDVs isolated from wild birds.
Amino Acid Sequence ; Amino Acids ; Avibirnavirus ; Base Sequence ; Birds ; Birnaviridae ; Chickens ; Genes, vif ; Genome ; Humans ; Infectious bursal disease virus ; Korea ; RNA, Double-Stranded ; Sequence Analysis ; Sprains and Strains