RESUMO
Protein V of Newcastle disease virus (NDV) serves as interferon (IFN) antagonist, and NDV stains with different pathogenicity show different abilities in inhibition IFN expression. To further reveal the relationship between viral virulence and their IFN-antagonistic activity derived from protein V, six NDV strains with three different pathotypes were used in this study and their V gene were cloned into eukaryotic expression vector. The V gene derived from different NDV strains were expressed in same level in cells after transfection according to the results from Western blotting. And these proteins showed different interferon-antagonistic activities based on interferon expression using Luciferase Reporter Assay and ELISA. The expression of IFN and viral virulence index, mean death time, have a good linear relationship indicating a good correlation between viral virulence and IFN antagonism of their V Protein.
Assuntos
Interferons/genética , Doença de Newcastle/genética , Vírus da Doença de Newcastle/genética , Proteínas Virais/genética , Animais , Linhagem Celular , Galinhas/virologia , Ensaio de Imunoadsorção Enzimática , Interferons/antagonistas & inibidores , Doença de Newcastle/virologia , Vírus da Doença de Newcastle/patogenicidade , Transfecção , VirulênciaRESUMO
Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection negatively impacts the efficacy of classical swine fever virus (CSFV) vaccine. This paper investigates whether the PRRSV vaccine also impacts the CSFV vaccine and if the impact is time-related. Forty-eight piglets born from four sows were divided into five groups (G1-G5). The piglets in G1 to G4 were given PRRSV vaccine at 14, 21, 28 and 35days of age. The G5 group was not vaccinated with the PRRSV. All pigs were given the CSFV vaccine at 35days of age. Immune responses to the CSFV vaccine were evaluated by testing CSFV-specific sera antibodies, lymphocyte proliferation and cytokine secretion. The results demonstrate that the PRRSV vaccine significantly reduces the immune responses of the CSFV vaccination when immunised both vaccines at the same time or with only a one week interval. The PRRSV vaccination induced higher levels of IL-10 expression in the first week and this may be why the CSFV vaccination is immunosuppressed. The findings indicate that a time interval of more than one week is necessary for vaccinated CSF after the PRRSV immunisation.
Assuntos
Peste Suína Clássica/prevenção & controle , Interleucina-10/metabolismo , Leucócitos Mononucleares/metabolismo , Síndrome Respiratória e Reprodutiva Suína/prevenção & controle , Regulação para Cima , Vacinas Virais/imunologia , Animais , Anticorpos Antivirais/sangue , Proliferação de Células , Peste Suína Clássica/virologia , Vírus da Febre Suína Clássica/fisiologia , Regulação da Expressão Gênica/imunologia , Interleucina-10/genética , Leucócitos Mononucleares/virologia , Vírus da Síndrome Respiratória e Reprodutiva Suína , Suínos , VacinaçãoRESUMO
The mucosal immune response against the porcine epidemic diarrhea virus (PEDV) is very important in piglets. To develop a PEDV vaccine suitable for inducing high levels of intestinal IgA in piglets, recombinant yeast expressing the PEDV S1 gene was constructed and tested by oral immunization of mice and piglets. The S1-specific IgG and IgA were tested at 0, 14, and 28 days postimmunization (dpi) in mice. Compared to the control group, the mice treated with S1 expressing yeast, demonstrated significantly higher levels of IgG and IgA against PEDV from 14 dpi onward. The recombinant yeast inducing a fecal IgA response in piglets was also tested. PEDV-specific IgA could be detected at 7 dpi and increased to 28 dpi. We demonstrated that whole recombinant yeast can be used as a PEDV vaccine vector for inducing high levels of IgA against PEDV in piglets. This could be a good vaccine candidate for PEDV control in piglets.
Assuntos
Infecções por Coronavirus/prevenção & controle , Imunoglobulina A/imunologia , Vírus da Diarreia Epidêmica Suína/imunologia , Doenças dos Suínos/prevenção & controle , Vacinas Virais/uso terapêutico , Administração Oral , Animais , Células Dendríticas/imunologia , Feminino , Imunidade nas Mucosas , Imunoglobulina A/análise , Mucosa Intestinal/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Plasmídeos/genética , Proteínas Recombinantes/imunologia , Saccharomyces/genética , Saccharomyces/imunologia , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Suínos , Transformação Genética , Vacinas Virais/administração & dosagemRESUMO
BACKGROUND: To assess the effectiveness of emergency vaccination for reducing the contact-induced infection and pathological damage caused by the highly pathogenic porcine reproductive and respiratory syndrome virus (HPPRRSV), Twenty pigs were equally divided into four groups. Groups 1, 2 and 3 were housed in one unit, whereas Group 4 was separately housed. Group 1 was challenged with HPPRRSV on day 0. Group 2 and 4 did not receive treatment and were used as the contact-infected and uninfected controls, respectively. Group 3 was treated with the attenuated vaccine at 0 days post-inoculation. The rectal temperatures, clinical signs, pathologic lesions and viraemia of the piglets were detected and evaluated. RESULTS: The vaccinated pigs in Group 3 showed less clinical morbidity, viraemia, temperature fluctuations and lung lesions at 14 days post-inoculation, as compared with the contact-infected (Group 2) and experimentally infected (Group 1) pigs. Higher serum IFN-γ levels were detected among the pigs that received emergency immunisation. Thus, IFN-γ may be involved in immunity against HPPRRSV infection. CONCLUSIONS: These results indicated that emergency vaccination could effectively alleviate HPPRRSV infection during experimental contact exposure. Our findings provide a novel and useful strategy for controlling clinical HPPRRSV.