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

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 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

This study examined the adjuvant effects of dimethyl dioctadecyl ammonium bromide (DDA), CpG oligodeoxynucleotides (CpG-ODN), and chicken interferon-gamma (ChIFN-gamma) on a DNA vaccine (pcDNA-VP243) against the infectious bursal disease virus (IBDV). A plasmid encoding chicken IFN-atilde was constructed. Twice at 2-week intervals, twoweek-old chickens were injected intramuscularly and intraperitoneally with either a DNA vaccine alone or a DNA vaccine together with the respective adjuvants. On week 2 after the second immunization, the chickens were orally challenged with the highly virulent IBDV. The groups that received the DNA vaccines plus either DDA or CpG-ODN showed significantly lower survival rates than the group that received the DNA vaccine alone. However, the survival rates for the DNA vaccine alone and for the DNA vaccine plus ChIFN-gamma were similar. The chickens had no detectable antibodies to the IBDV before the challenge but all the surviving chickens in all groups except for the normal control group showed the induction of antibodies to the IBDV at day 10 after the challenge. As judged by the lymphocyte proliferation assays using the a WST-8 solution performed on the peripheral blood and splenic lymphocytes, the stimulation indices (SI) of the peripheral blood lymphocytes in all groups except for the normal control group were similar immediately before the challenge. At 10 days post-challenge, the SI for DNA vaccine plus either CpG-ODN or ChIFN-gamma was similar to that of the DNA vaccine control group. For splenic lymphocytes, the SI in the DNA vaccine plus CpG-ODN and DNA vaccine plus ChIFN-gamma groups were higher than for the DNA vaccine control. These results suggest that DDA actually compromises the protection against the IBDV by DNA vaccine, and CpG-ODN and IFN-gamma had no significant effect.
Adjuvants, Immunologic ; Animals ; Antibodies, Viral/blood ; Birnaviridae Infections/*immunology/*prevention & control/virology ; Bursa of Fabricius/immunology/virology ; Cell Proliferation ; Chickens ; CpG Islands/immunology ; Enzyme-Linked Immunosorbent Assay/veterinary ; Immunization/methods/*veterinary ; Infectious bursal disease virus/*immunology ; Interferon-gamma/immunology/therapeutic use ; Lymphocytes/cytology/immunology ; Oligonucleotides/immunology ; Poultry Diseases/immunology/*prevention & control/*virology ; Specific Pathogen-Free Organisms ; Vaccines, DNA/immunology/therapeutic use ; Viral Vaccines/*immunology/therapeutic use

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

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