Teleost TLR22 recognizes RNA duplex to induce IFN and protect cells from birnaviruses.
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TLR22 occurs exclusively in aquatic animals and its role is unknown. Herein we show that the fugu (Takifugu rubripes) (fg)TLR3 and fgTLR22 link the IFN-inducing pathway via the fg Toll-IL-1R homology domain-containing adaptor protein 1(fgTICAM-1, or TRIF) adaptor in fish cells. fgTLR3 resides in endoplasmic reticulum and recognizes relatively short-sized dsRNA, whereas fgTLR22 recognizes long-sized dsRNA on the cell surface. On poly(I:C)-stimulated fish cells, both recruit fgTICAM-1, which in turn moves from the TLR to a cytoplasmic signalosome region. Thus, fgTICAM-1 acts as a shuttling platform for IFN signaling. When fish cells expressing fgTLR22 are exposed to dsRNA or aquatic dsRNA viruses, cells induce IFN responses to acquire resistance to virus infection. Thus, fish have a novel TICAM-1-coupling TLR that is distinct from the mammalian TLR3 in cellular localization, ligand selection, and tissue distribution. TLR22 may be a functional substitute of human cell-surface TLR3 and serve as a surveillant for infection with dsRNA virus to alert the immune system for antiviral protection in fish. (+info)
Detection of vaccine-like infectious bursal disease (IBD) virus in IBD vaccine-free chickens in Japan.
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The prevalence of infectious bursal disease virus (IBDV) was studied in chickens, which had not been vaccinated against IBD. Fifty sera and forty-six bursae of Fabricius from chickens showing impaired growth, collected from 7 IBD vaccination-free farms in Japan were used for virus neutralization (VN) tests and RT-PCR for detection of IBDV genome corresponding to the VP2 hypervariable region. Of the fifty sera, 39 sera (78%) from 6 farms were VN antibodies positive. Of the forty-six bursae, 37 bursae (80.4%) from 6 farms were positive in the RT-PCR assay. The sequences of all the RT-PCR products detected in this study were closely related or identical to those of the vaccine strains. These results show that vaccine-like IBDV is prevalent even in IBD vaccine-free chicken farms in Japan. (+info)
Homologous recombination is apparent in infectious bursal disease virus.
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Protection of rainbow trout from infectious hematopoietic necrosis (IHN) by injection of infectious pancreatic necrosis virus (IPNV) or poly(I:C).
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Protection of chicken against very virulent IBDV provided by in ovo priming with DNA vaccine and boosting with killed vaccine and the adjuvant effects of plasmid-encoded chicken interleukin-2 and interferon-gamma.
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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 killedvaccine 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. (+info)
Rapid detection of Infectious bursal disease virus by reverse transcription loop-mediated isothermal amplification assay.
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A reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed for the rapid identification of Infectious bursal disease virus (IBDV). The RT-LAMP assay used a set of 4 primers to amplify the viral protein 2 gene of IBDV for the detection of IBDV, showing not only high efficiency but also analytic specificity. The data demonstrated that the RT-LAMP assay detected 30 different IBDV isolates, had no cross-reaction with 3 other avian viruses (Infectious bronchitis virus, Newcastle disease virus, and Avian influenza virus), and obtained a 95.45% sensitivity in 22 positive clinical samples in reference to virus isolation. Therefore, this rapid, specific, sensitive, and convenient RT-LAMP assay could be applicable to the identification of IBDV in less-equipped laboratories as well as in the field. (+info)
Effect of the polysaccharide extract from the edible mushroom Pleurotus ostreatus against infectious bursal disease virus.
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Effect of Sophy beta-glucan on immunity and growth performance in broiler chicken.
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This study was carried out to determine the effect of Sophy beta-glucan on immunity and growth performance in broilers. One group was treated with 1% beta-glucan ad libitum with water and the other group was kept as the control. Vaccination for Infectious Bursal Disease was carried out on days 16 and 21. Blood samples were collected from birds, and antibody titres against IBD were measured. The mean body weight of the beta-glucan treated group was significantly (P<0.05) higher than that of the control group. The mean antibody titres measured on days 25, 36 and 42 were significantly (P<0.05) higher in 1% beta-glucan treated group than that of the control group, suggesting the presence of immune stimulating effect of beta-glucan. (+info)