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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. Source

Ye Y.,Key Laboratory of Animal Vaccine Development | Ye Y.,South China Agricultural University | Ye Y.,National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control | Yan G.,Jinan University | And 12 more authors.
Journal of Proteome Research | Year: 2013

Foot-and-mouth disease virus (FMDV) is an important disease agent that can be difficult to effectively eradicate from herds. Because it is an obligate intracellular parasite, the virus has multiple effects on the host cell during infection. Here, a high-throughput quantitative proteomic approach was used to develop an unbiased holistic overview of the protein changes in IBRS-2 cells infected with FMDV. Stable isotope labeling with amino acids in cell culture (SILAC) combined with LC-MS/MS was performed to identify and quantify 1260 cellular and 2 viral proteins after 6 h of infection of IBRS-2 cells with FMDV. Of these identified and measured cellular protein pairs, 77 were significantly up-regulated, and 50 were significantly down-regulated based on significance B ≥ 0.05. The differentially altered proteins included a number of proteins involved in endolysosomal proteases system, cell cycle, cellular growth and proliferation, and immune cell trafficking. Selected data were validated by Western blot. Ingenuity Pathway Analysis revealed that proteins that changed in response to infection could be assigned to defined canonical pathways and functional groupings, such as integrin signaling. The obtained data might not only improve the understanding of the dynamics of FMDV and host interaction but may also help elucidate the pathogenic mechanism of FMDV infection. © 2012 American Chemical Society. Source

Zhang J.,Key Laboratory of Animal Vaccine Development | Zhang J.,South China Agricultural University | Chen X.-W.,Key Laboratory of Animal Vaccine Development | Chen X.-W.,South China Agricultural University | And 7 more authors.
Vaccine | Year: 2014

Avian infectious bronchitis virus (IBV) is associated with production inefficiencies in domestic fowl, and causes massive economic losses to the poultry industry worldwide. Progress has been made in designing novel and efficient candidate vaccines to control IBV infection. BacMam virus, a modified baculovirus mediating transgene expression under the control of a mammalian promoter, has emerged as a versatile and safe vector during vaccine development. In previous work, we generated the BacMam virus Ac-CMV-S1, which expressed the S1 glycoprotein of IBV-M41. We showed that Ac-CMV-S1 induced excellent cellular immunity, but did not confer adequate protection in chickens compared with the conventional inactivated vaccine. In the current study, we generated an improved BacMam virus, BV-Dual-S1. This virus displayed the S1 glycoprotein on the baculovirus envelope, and was capable of expressing it in mammalian cells. BV-Dual-S1 elicited stronger humoral and cell-mediated immune responses, and showed greater capacity for induction of cytotoxic T lymphocyte responses, compared with Ac-CMV-S1 in specific pathogen-free chickens. A significant difference was not observed for protection rates between chickens immunized with BV-Dual-S1 (83%) or inactivated vaccine (89%) following challenge with virulent IBV-M41. Our findings show that the protective efficacy of BV-Dual-S1 could be significantly enhanced by baculovirus display technology. BacMam virus-based surface display strategies could serve as effective tools in designing vaccines against IB and other infectious diseases. © 2013. Source

Ye Y.,Key Laboratory of Animal Vaccine Development | Ye Y.,South China Agricultural University | Cheng X.,Key Laboratory of Animal Vaccine Development | Cheng X.,South China Agricultural University | And 9 more authors.
Virology Journal | Year: 2013

Background: Porcine circovirus type 2 (PCV2) is associated with post-weaning multisystemic wasting syndrome (PMWS), an emerging swine disease that causes progressive weight loss, dyspnea, tachypnea, anemia, jaundice, and diarrhea in piglets. Although baculovirus is an enveloped virus that infects insects in nature, it has emerged as a vaccine vector, and we used it to develop a novel candidate vaccine for a preventive or therapeutic strategy to control PCV2 infections. Methods. Immunoblotting analysis of recombinant baculovirus and immunofluorescent staining of baculovirus-infected cells were followed using anti-ORF2 monoclonal antibodies. The BALB/c mice were immunized intramuscularly with this baculovirus. The titers of antibodies were mensurated with a Cap-protein-specific enzyme-linked immunosorbent assay (ELISA) and a serum neutralization assay. The IFN-γ response in splenocytes harvested from immunized mice was measured by ELISA. Student's t-test was used to compare immune responses of different groups. Results: In this study, we successfully constructed a dual-expression-system-based recombinant baculovirus BV-GD-ORF2, which can display the PCV2 capsid (Cap) protein and VSV-G protein on the viral envelope and also expressing Cap protein on transduced mammalian cells, thereby functioning as both a subunit and a DNA vaccine. After infection, the Cap protein was expressed and displayed on the viral surface, as demonstrated with an indirect fluorescence assay and immunoblotting. The vaccination of mice with recombinant baculovirus BV-GD-ORF2 successfully induced robust Cap-protein-specific humoral and cellular immune responses. Conclusions: Our findings collectively demonstrate that the recombinant baculovirus BV-GD-ORF2 is a potential vaccine against PCV2 infections. © 2013 Ye et al.; licensee BioMed Central Ltd. Source

Jiao P.,National and Regional Joint Engineering Laboratory | Jiao P.,Key Laboratory of Animal Vaccine Development | Jiao P.,Key Laboratory of Zoonosis Prevention and Control of Guangdong | Jiao P.,South China Agricultural University | And 30 more authors.
Frontiers in Microbiology | Year: 2016

H5N1 highly pathogenic avian influenza (HPAI) was one of the most important avian diseases in poultry production of China, especially in Guangdong province. In recent years, new H5N1 highly pathogenic avian influenza viruses (HPAIV) still emerged constantly, although all poultry in China were immunized with H5N1 vaccinations compulsorily. To better understand the pathogenicity and transmission of dominant clades of the H5N1 HPAIVs in chicken from Guangdong in 2012, we chose a clade 7.2 avian influenza virus named A/Chicken/China/G2/2012(H5N1) (G2) and a clade avian influenza virus named A/Duck/China/G3/2012(H5N1) (G3) in our study. Our results showed that the chickens inoculated with 103 EID50 of G2 or G3 viruses all died, and the titers of virus replication detected in several visceral organs were high but different. In the naive contact groups, virus shedding was not detected in G2 group and all chickens survived, but virus shedding was detected in G3 group and all chickens died. These results showed that the two clades of H5N1 HPAIVs had high pathogenicity in chickens and the contact transmission of them was different in chickens. The results of cross reactive HI assay showed that antigens of G2 and G3 were very different from those of current commercial vaccines isolates (Re-4, Re-6, and D7). And to evaluate the protective efficacy of three vaccines against most isolates form Guangdong belonging to clade in 2012, G3 was chosen to challenge the three vaccines such as Re-4, Re-6, and D7. First, chickens were immunized with 0.3 ml Re-4, Re-6, and D7 inactivated vaccines by intramuscular injection, respectively, and then challenged with 106 EID50 of G3 on day 28 post-vaccination. The D7 vaccine had 100% protection against G3 for chickens, the Re-6 vaccine had 88.9%, and the Re-4 vaccine only had 66.7%. Our results suggested that the D7 vaccine could prevent and control H5N1 virus outbreaks more effectively in Guangdong. From the above, it was necessary to conduct continuously epidemiological survey and study the pathogenicity and antigenic variation of avian influenza in Southern China. © 2016 Jiao, Song, Liu, Song, Cui, Wu, Ye, Qu, Zhang and Liao. Source

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