Key Laboratory of Animal Vaccine Development

Guangzhou, China

Key Laboratory of Animal Vaccine Development

Guangzhou, China
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Kang Y.,South China Agricultural University | Kang Y.,Sun Yat Sen University | Kang Y.,Key Laboratory of Animal Vaccine Development | Yuan R.,South China Agricultural University | And 21 more authors.
Oncotarget | Year: 2017

Viral infection activates a host's cellular phosphatidylinositol 3-kinase (PI3K)/ Akt signaling pathway, which is involved in cell differentiation, growth, survival, and apoptosis. To elucidate molecular mechanisms in the pathogenesis of Newcastle disease virus (NDV), we demonstrated that NDV transiently activates the PI3K/Akt pathway in chicken cells at an early phase of infection. Its activation was observed as early as 15 min post-infection and gradually weakened after 24 h. Incubating cells with a PI3K inhibitor, LY294002 or wortmannin, prior to NDV infection decreased NDV progeny yields and suppressed Akt phosphorylation at early times post-infection. Akt activation is triggered by NDV-GM or NDV-F48E9 and is abolished by methyl ß-cyclodextrin and chlorpromazine. Treatment following NDV-La Sota infection had no obvious effect. However, inhibiting PI3K activation promoted apoptotic responses during an early stage of NDV infection. The pan caspase inhibitor ZVAD-FMK mitigated the reduction in Akt phosphorylation by inhibiting PI3K activation, which indicates the signaling pathway promotes cell survival and, in turn, facilitates viral replication. By suppressing premature apoptosis upon NDV infection, the PI3K/Akt pathway enhances the anti-apoptotic response.

Wei L.,National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control | Wei L.,Key Laboratory of Animal Vaccine Development | Wei L.,Key Laboratory of Zoonosis Prevention and Control of Guangdong | Wei L.,South China Agricultural University | And 34 more authors.
Veterinary Immunology and Immunopathology | Year: 2013

In mammals, Toll-like receptor 7 (TLR7) is an important membrane-bound receptor triggered by antiviral compounds and single-stranded RNA. It is implicated in the immune response to viruses such as influenza virus. It was not known whether geese, a natural host for avian influenza viruses, possess a homologue of mammalian TLR7 for recognizing avian influenza virus. In this study, we cloned the full-length of goose TLR7 and partial sequences of its adaptor protein, myeloid differentiation factor 88 (MyD88), some antiviral molecules such as RNA-dependent protein kinase (PKR) and 2',5'-oligoadenylate synthetase (OAS). Goose TLR7 has a protein secondary structure identical to that of mammals, consisting of several leucine-rich domains, a transmembrane domain, and Toll/interleukin-1 receptor domain. To further understand whether the MyD88-dependent pathway of TLR7 is involved in the antiviral innate immune response against highly pathogenic avian influenza virus (HPAIV) infection in geese, we inoculated geese with an H5N1 HPAIV isolated from ducks in 2004. The virus, A/Duck/Guangdong/212/2004, replicated in various tissues resulting in 40% mortality. Quantitative real-time PCR analysis showed upregulation of mRNA transcripts for TLR7, MyD88, PKR and OAS in the lungs of geese at 1, 2 and 3 days post-inoculation. Therefore, the MyD88-dependent pathway of TLR7 was involved in the early stage of antiviral innate immune response in geese during H5N1 HPAIV infection. © 2013.

Zhang Z.,South China Agricultural University | Zhang Z.,National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control | Zhang Z.,Key Laboratory of Animal Vaccine Development | Zhang Z.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province | And 26 more authors.
Veterinary Microbiology | Year: 2017

H5N1, a highly pathogenic avian influenza virus (HPAIV), poses a significant threat to poultry and human health. However, currently available inactivated influenza vaccines are less efficacious against viruses that display antigenic drift. In this study, we constructed a recombinant baculovirus (BV-HMNN) expressing four conserved antigen epitopes: H5N1 hemagglutinin stem area amino acids 76–130 (HA2 76–130); three tandem repeats from the ectodomain of the conserved influenza matrix protein M2 (3M2e); nucleoprotein amino acids 55–69 (NP55–69); and nucleoprotein amino acids 380–393 (NP380–393). We evaluated the immunogenicity and protective efficacy of coimmunization with an inactivated avian influenza virus vaccine (Re6) and the recombinant baculovirus (BV-HMNN) against heterologous viral infection in specific-pathogen-free chickens. The chickens immunized with both vaccines (Re6 + BV-HMNN) achieved complete protection, was significantly greater than that of chickens vaccinated with Re6 alone. BV-HMNN-supplemented vaccination also reduced viral shedding more effectively than nonsupplemented vaccination. We conclude that coimmunization with both vaccines was superior to immunization with the inactivated vaccine alone in inducing cross-protection against heterologous H5N1 virus. © 2017

Wang H.,South China Agricultural University | Wang H.,Key Laboratory of Comprehensive Prevention and Control for Severe Clinical Animal Diseases | Ji F.,South China Agricultural University | Ji F.,Key Laboratory of Animal Vaccine Development | And 7 more authors.
PLoS ONE | Year: 2015

The hepatitis E virus (HEV) is responsible for serious viral hepatitis worldwide. Animals are considered a reservoir of HEV, particularly pigs. While HEV infection in pigs and dogs is always asymptomatic, the virus causes high death rates in patients with pre-existing chronic liver disease and pregnant women in developing countries. HEV open reading frame 2 (ORF2) has been used as a diagnostic target to detect specific antibodies against HEV in serum samples. Recent research has additionally supported the potential utility of the ORF3 protein as a target in serum anti-HEV detection. However, the epitope distribution of ORF3 protein remains ambiguous. In the current study, we showed that continuous amino acid motif, VDLP, at the C-terminus of genotype 4 HEV ORF3 is a core sequence of the ORF3 protein epitope. Moreover, cooperative interaction with upstream elements is essential for its immunoactivity. Three proline residues (P99, P102 and P103) in the upstream proline-rich domain exerted significant effects on the immunocompetence of VDLP. ELISA results revealed that SAPPLPPVVDLP and SAPPLPPVVDLPQLGL peptides containing the identified VDLP epitope display weaker reactions with anti-HEV serum than the commercial ELISA kit. Our collective findings provide valuable information on the epitope distribution characteristics of HEV ORF3 and improve our understanding of the influence of the proline-rich domain on the immunoactivity of downstream amino acids in the C-terminal region. © 2015 Wang et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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