Infectious bursal disease virus(IBD) causes infectious bursal disease (IBD), which infects bursal of chicken and can evoke immune suppression. This study identified the antigenic epitopes of four McAbs to IBDV VP3(HRB-3F, HRB-7B, HRB-7C and HRB-10E)with pepscan. A set of 17 partially overlapping or consecutive peptides (P1-P17) spanning VP3 were expressed for epitope screening by pepscan. Finally, two antigenic epitopes, 109-119aa and 177-190aa of IBDV VP3, were identified by Western blot and ELISA. The peptides on epitopes could react with IBDV, and they had better immunnogenicity. The sequences of epitopes were compared with that of several other IBDV strains in the same region, and was found they were totally homologous. This study showed the two epitopes were novel conserved linear B cell epitopes on the VP3 of IBDV. This study provides basis for the development of immunity-based prophylactic, therapeutic and diagnostic measures for control of IBD and further for structural and functional analysis of IBDV.
Animals ; Antibodies, Monoclonal ; immunology ; Antibodies, Viral ; blood ; immunology ; Blotting, Western ; Capsid Proteins ; genetics ; immunology ; metabolism ; Enzyme-Linked Immunosorbent Assay ; Epitopes ; genetics ; immunology ; metabolism ; Immune Sera ; immunology ; Immunization ; Immunohistochemistry ; Infectious bursal disease virus ; genetics ; immunology ; metabolism ; Mice ; Mice, Inbred BALB C

Protective immune response of the available IBD vaccine is insufficient to fully protect against the prevailing strain of the infectious bursal disease virus (IBDV). Such a vaccination escape IBDV field isolate idenfied from Anhui province of China in December 2007, where IBD broke out at 2 weeks post vaccination. The IBDV vp2 gene was cloned into pFastBacHTA donor plasmid, followed by generation of the recombinant bacmid DNA pBac-VP2. The latter was used to transfect insect cell Sf9 with Lipofectamine to produce recombinant baculovirus vBac-VP2. The Sf9 cells infected with vBac-VP2 were stained positive against IBDV antibody using the indirect immunofluorescence assay (IFA), which was also confirmed by the detection of IBDV Vp2 protein in the infected Sf9 cells by IBDV sandwich ELISA. Western blotting revealed that the calculated protein of approximately 53 kDa was in the expressed in the insect cells. Moreover, virus-like particles (VLPs) and "inclusion body-like"structure in the infected Sf9 cells were observed under electron microscopy. We further developed an indirect ELISA for the detection of the IBDV antibodies, which was specific and sensitive. In addition, the lysates of vBac-VP2 infected cells was used to immunize 2-week-old SPF chickens, followed by challenging with the virulent IBDV, the survival rate was 30% at 14 days post primary immunization, however, the survival rate was 100% at 14 d after the booster vaccination. The ELISA antibody titers was up to 3.2 x 10(3) and neutralization antibody titer was 2536, significantly higher than those of one-shot vaccination, 8 x 10(2) and 1106, respectively. The immunized chickens did not show any clinical signs and histopathological changes of infection in 7-days trial time. The bursa/body-weight ratios were higher than those of the unimmunized control (P < 0.05). The virus-like-particle recombinant Vp2 protein expressed in insect cells promises to be a novel subunit vaccine and diagnostic reagent candidate for IBDV.
Animals ; Baculoviridae ; genetics ; Cell Line ; Chickens ; Infectious bursal disease virus ; immunology ; Insecta ; genetics ; metabolism ; Poultry Diseases ; prevention & control ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Viral Structural Proteins ; biosynthesis ; genetics ; Viral Vaccines ; immunology

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*

Infectious bursal disease virus (IBDV), the causative agent of a highly contagious disease in chickens, carries a small nonstructural protein (NS). In this study, vvIBDV Gx-VP5 genes were cloned into plasmid pET30a( + ) and expressed in E. coli with IPTG inducing. BALB/c mice were immunized with the purified recombinant fusion protein. SP2/0 myeloma cells and spleen cells of BALB/c mice were fused by PEG(MW1500), three hybridoma cell lines were examined by indirect ELISA and clone for three times by limited dilution, and were named as 4B4, 6D12, 3E8. The subtype of the monoclonal antibodies were IgG1 with a subtype identified ELISA kit, and light chains were kappa. The ascites titers of monoclonal antibodies were 5 x 10(4), 3.5 x 10(4), 3 x 10(4) by indirect ELISA, respectively. Indirect ELISA and Western blot results showed that the monoclonal antibodies only acted with VP5 protein, IF analysis indicated that three monoclonal antibodies acted with IBDV Gt. There were specific fluorescence in detected Vero E6 cells which transient expressed VP5 protein by IFA. Therefore, monoclonal antibodies specific to IBDV VP5 proteins are specific method for detected VP5 proteins, and base on establish stabilize expressed VP5 protein Vero cell lines to research IBDV VP5 protein function.
Animals ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Antibodies, Viral ; biosynthesis ; immunology ; Chickens ; Escherichia coli ; genetics ; metabolism ; Female ; Hybridomas ; secretion ; Immunization ; Infectious bursal disease virus ; immunology ; Mice ; Mice, Inbred BALB C ; Viral Nonstructural Proteins ; immunology

The ability of a heat-inactivated whole virus from a highly virulent infectious bursal disease virus (hvIBDV) and VP2 protein from hvIBDV expressed in E. coli provided protection against a hvIBDV challenge in specificpathogen- free (SPF) chickens. Six out of seven chickens that were injected three times with crude VP2 protein developed significant antibody titer against IBDV. However, only four out of the seven chickens survived the hvIBDV challenge. Despite showing low antibody titer profiles, all chickens immunized with the heat-inactivated whole virus also survived the challenged with hvIBDV. However, all of these chickens had bursal atrophy and mild to moderate depletion of lymphocytes. Thus, antibodies raised against IBDV VP2 protein expressed in E. coli and denatured IBDV proteins induced some degree of protection against mortality but not against bursal damage following challenge with hvIBDV.
Animals ; Antibodies, Viral/blood ; Birnaviridae Infections/immunology/prevention & control/*veterinary/virology ; Chickens ; Enzyme-Linked Immunosorbent Assay/veterinary ; Escherichia coli/genetics ; Immunization/standards/*veterinary ; Infectious bursal disease virus/genetics/*immunology/pathogenicity ; Poultry Diseases/*immunology/prevention&control/virology ; Recombinant Proteins/genetics/*immunology ; Specific Pathogen-Free Organisms ; Vaccines, Attenuated/immunology/pharmacology ; Vaccines, Synthetic/immunology/pharmacology ; Viral Structural Proteins/biosynthesis/genetics/*immunology ; Viral Vaccines/*immunology/pharmacology

A transfer plasmid vector pUC18-US10-VP2 was first constructed by inserting the gene of the enhancer green fluorescent protein(eGFP) fused to the VP2 gene of very virulent Infectious bursal disease virus (IBDV) JS strain into the US10 fragment of the Marek's disease virus (MDV) CV1988/Rispens. The recombinant virus, designated as rMDV, was developed by co-transfecting CEF with the transfer plasmid vector and simultaneously infecting with the CVI988/Rispens virus. The PCR and IFA results indicated that the rMDV is stable after 31 passages. Chickens vaccinated with rMDV were protected from challenge with 100LD50 of IBDV JS. The protection ratio of the chickens vaccinated with the 1000PFU, 2000PFU, 5000PFU of the rMDV were 50%, 60%, and 80% respectively. It is interesting that the average histopathology BF lesion scores of chicken group immunized with 5000PFU of rMDV by one-time vaccination was close to that of chicken group vaccinated with IBDV live vaccine NF8 strain for twice (2.0/1.5). There is no difference in protection between the groups (P > 0.05) but significent difference between groups immunized with 5000 PFU of rMDV and with normal MDV. This demonstrated that rMDV expressing VP2 fusion protein was effective vaccine against IBDV in SPF chickens.
Animals ; Birnaviridae Infections ; prevention & control ; veterinary ; Chickens ; Genetic Vectors ; Green Fluorescent Proteins ; genetics ; Infectious bursal disease virus ; genetics ; immunology ; Mardivirus ; genetics ; metabolism ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Recombination, Genetic ; Transfection ; Vaccination ; Vaccines, DNA ; genetics ; immunology ; Viral Structural Proteins ; biosynthesis ; genetics ; immunology ; Viral Vaccines ; genetics ; immunology

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

The aim of this study was to examine the efficacy of in ovo prime-boost vaccination against infectious bursal disease virus (IBDV) using a DNA vaccine to prime in ovo followed by a killed-vaccine boost post hatching. In addition, the adjuvant effects of plasmid-encoded chicken interleukin-2 and chicken interferon-gamma were tested in conjunction with the vaccine. A plasmid DNA vaccine (pcDNA-VP243) encoding the VP2, VP4, and VP3 proteins of the very virulent IBDV (vvIBDV) SH/92 strain was injected into the amniotic sac alone or in combination with a plasmid encoding chicken IL-2 (ChIL-2) or chicken IFN-gamma (ChIFN-gamma) at embryonation day 18, followed by an intramuscular injection of a commercial killed IBD vaccine at 1 week of age. The chickens were orally challenged with the vvIBDV SH/92 strain at 3 weeks of age and observed for 10 days. In ovo DNA immunization followed by a killed-vaccine boost provided significantly better immunity than the other options. No mortality was observed in this group after a challenge with the vvIBDV. The prime-boost strategy was moderately effective against bursal damage, which was measured by the bursa weight/body weight ratio, the presence of IBDV RNA, and the bursal lesion score. In ovo DNA vaccination with no boost did not provide sufficient immunity, and the addition of ChIL-2 or ChIFN-gamma did not enhance protective immunity. In the ConA-induced lymphocyte proliferation assay of peripheral blood lymphocyte collected 10 days post-challenge, there was greater proliferation responses in the DNA vaccine plus boost and DNA vaccine with ChIL-2 plus boost groups compared to the other groups. These findings suggest that priming with DNA vaccine and boosting with killed vaccine is an effective strategy for protecting chickens against vvIBDV.
Adjuvants, Immunologic/pharmacology ; Animals ; Antibodies, Viral/blood ; Birnaviridae Infections/immunology/prevention & control/*veterinary/virology ; Body Weight/immunology ; Bursa of Fabricius/immunology ; Chick Embryo ; *Chickens ; Histocytochemistry/veterinary ; Immunization/*veterinary ; Infectious bursal disease virus/genetics/*immunology ; Interferon-gamma/pharmacology ; Interleukin-2/pharmacology ; Organ Size/immunology ; Poultry Diseases/immunology/*prevention & control/virology ; RNA, Viral/chemistry/genetics ; Random Allocation ; Reverse Transcriptase Polymerase Chain Reaction/veterinary ; Specific Pathogen-Free Organisms ; Vaccines, DNA/*administration & dosage/immunology ; Vaccines, Inactivated/administration & dosage/immunology ; Viral Vaccines/*administration & dosage/immunology