The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Huaji Qiu - One of the best experts on this subject based on the ideXlab platform.
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Enhanced protective immunity of the chimeric vector-based vaccine rAdV-SFV-E2 against classical Swine fever in pigs by a Salmonella bacterial ghost adjuvant
Veterinary Research, 2016Co-Authors: Shui-li Xia, Yuan Sun, Jian-lin Lei, Yimin Wang, Xin Cong, Guang-tao Xiang, Siguo Liu, Huaji QiuAbstract:AbstractClassical Swine fever (CSF) is a highly contagious Swine Disease caused by classical Swine fever virus (CSFV). Previously, we demonstrated that rAdV-SFV-E2, an adenovirus-delivered, Semliki Forest virus replicon-vectored marker vaccine against CSF, is able to protect pigs against lethal CSFV challenge. From an economical point of view, it will be beneficial to reduce the minimum effective dose of the vaccine. This study was designed to test the adjuvant effects of Salmonella enteritidis-derived bacterial ghosts (BG) to enhance the protective immunity of rAdV-SFV-E2 in pigs. Groups of 5-week-old pigs (n = 4) were immunized intramuscularly twice with 105 median tissue culture infective doses (TCID50) rAdV-SFV-E2 combined with 1010 colony forming units (CFU) BG, 106 or 105 TCID50 rAdV-SFV-E2 alone or 1010 CFU BG alone at an interval of 3 weeks, and challenged with the highly virulent CSFV Shimen strain at 1 week post-booster immunization. The results show that the pigs inoculated with 105 TCID50 rAdV-SFV-E2 plus BG or 106 TCID50 rAdV-SFV-E2 alone were completely protected from lethal CSFV challenge, in contrast with the pigs vaccinated with 105 TCID50 rAdV-SFV-E2 or BG alone, which displayed partial or no protection following virulent challenge. The data indicate that BG are a promising adjuvant to enhance the efficacy of rAdV-SFV-E2 and possibly other vaccines.
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comprehensive evaluation of the adenovirus alphavirus replicon chimeric vector based vaccine radv sfv e2 against classical Swine fever
Vaccine, 2013Co-Authors: Yuan Sun, Dayong Tian, Qilin Meng, Bibo Zhao, Lijun Ling, Yajin Liao, Huaji QiuAbstract:Abstract Classical Swine fever (CSF) is an economically important, highly contagious Swine Disease caused by classical Swine fever virus (CSFV). Marker vaccines and companion serological diagnostic tests are thought to be a promising strategy for future control and eradication of CSF. Previously, we have demonstrated that an adenovirus-vectored Semliki forest virus replicon construct expressing the E2 glycoprotein from CSFV, rAdV-SFV-E2, induced sterile immunity against a lethal CSFV challenge. In this study, we further evaluated the vaccine with respect to its safety, number and dose of immunization, and effects of maternally derived antibodies, re-immunization of the vaccine or co-administration with pseudorabies vaccine on the vaccine efficacy. The results showed that: (1) the vaccine was safe for mice, rabbits and pigs; (2) two immunizations with a dose as low as 6.25 × 10 5 TCID 50 or a single immunization with a dose of 10 7 TCID 50 rAdV-SFV-E2 provided complete protection against a lethal CSFV challenge; (3) maternally derived antibodies had no inhibitory effects on the efficacy of the vaccine; (4) the vaccine did not induce interfering anti-vector immunity; and (5) co-administration of rAdV-SFV-E2 with a live pseudorabies vaccine induced antibodies and protection indistinguishable from immunization with either vaccine administered alone. Taken together, the chimeric vaccine represents a promising marker vaccine candidate for control and eradication of CSF.
Chienjin Huang - One of the best experts on this subject based on the ideXlab platform.
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Enhancing expression of the classical Swine fever virus glycoprotein E2 in yeast and its application to a blocking ELISA
Journal of Biotechnology, 2014Co-Authors: Chih-yuan Cheng, Guang-jan Lin, Maw-sheng Chien, Wei-cheng Lee, Chienjin HuangAbstract:Classical Swine fever virus (CSFV) infection is a severe Swine Disease, often causing large economic losses. A Pichia pastoris yeast-expressed CSFV glycoprotein E2 (yE2) has been shown to induce a protective immune response against the virus. To improve the expression level of yE2, the first codon of E2 gene, Arg (CGG), which is the least used in P. pastoris, was optimized to the most favorite codon AGA. The yield of E2 protein was remarkably increased in the codon optimized strain (N342). Three truncated E2 subunits encoding the N-terminal 330 (N330), 301 (N301), and 190 (N190) residues, respectively, were also constructed. The immunogenicity of each recombinant E2 subunits was confirmed by immunization of pigs, and all immunized groups demonstrated high neutralizing antibody titers after boost immunization, which lasted for a long period of time. In addition, a monoclonal antibody (MAb), 1B6, specific to yE2, was generated and shown to recognize CSFV-infected cells. A panel of Swine sera were tested by peroxidase-conjugated MAb 1B6-based blocking enzyme-linked immunosorbent assay (ELISA) using N330 as coated antigen, and the assay demonstrated high sensitivity and specificity. The recombinant yE2 subunits may provide potential subunit vaccine candidates and useful diagnostic reagents for CSFV with easy manipulation and low cost.
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Yeast-expressed classical Swine fever virus glycoprotein E2 induces a protective immune response.
Veterinary Microbiology, 2009Co-Authors: Guang-jan Lin, Ting-yu Liu, Yu-yao Tseng, Zeng-weng Chen, Chia-chin You, Shih-ling Hsuan, Maw-sheng Chien, Chienjin HuangAbstract:Abstract Classical Swine fever (CSF) is an economically important Swine Disease worldwide. The glycoprotein E2 of classical Swine fever virus (CSFV) is a viral antigen that can induce a protective immune response against CSF. A recombinant E2 protein was constructed using the yeast Pichia pastoris expression system and evaluated for its vaccine efficacy. The yeast-expressed E2 (yE2) was shown to have N-linked glycosylation and to form homodimer molecules. Four 6-week-old specified-pathogen-free (SPF) piglets were intramuscularly immunized with yE2 twice at 3-week intervals. All yE2-vaccinated pigs could mount an anamnestic response after booster vaccination with neutralizing antibody titers ranging from 1:96 to 1:768. Neutralizing antibody titers at 10 weeks post booster vaccination ranged from 1:16 to 1:64. At this time, the pigs were subjected to challenge infection with a dose of 1 × 105 TCID50 (50% tissue culture infective dose) virulent CSFV strain. At 1 week post challenge infection, all of the yE2-immunized pigs were alive and without symptoms or signs of CSF. Neutralizing antibody titers at this time ranged from 1:4,800 to 1:12,800 and even to 1:51,200 one week later. In contrast, the control pigs continuously exhibited signs of CSF and had to be euthanized because of severe clinical symptoms at 6 days post challenge infection. All of the yE2-vaccinated pigs were Erns antibody negative and had seroconverted against Erns by post challenge day 11, suggesting that yE2 is a potential DIVA (differentiating infected from vaccinated animals) vaccine. The yeast-expressed E2 protein retains correct immunogenicity and is able to induce a protective immune response against CSFV infection.
C. Terpstra - One of the best experts on this subject based on the ideXlab platform.
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Vesicular Swine Disease in The Netherlands
Tijdschrift voor diergeneeskunde, 1992Co-Authors: C. TerpstraAbstract:The clinical signs, diagnosis and epizootiology of Swine vesicular Disease (SVD) are described. The clinical appearance is illustrated by photographs of experimentally and naturally infected pigs. Special attention is paid to differences between SVD and foot-and-mouth Disease (FMD) and to the choice of disinfectants.
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Lelystad virus, the cause of porcine epidemic abortion and respiratory syndrome: a review of mystery Swine Disease research at Lelystad
Veterinary microbiology, 1992Co-Authors: G. Wensvoort, Marcel Hulst, E.p. De Kluyver, R. J. M. Moormann, J.m.a. Pol, A. Den Besten, F. Wagenaar, R. Bloemraad, T. Zetstra, C. TerpstraAbstract:This paper reviews the laboratory investigations that led us to isolate the Lelystad virus and demonstrate that this virus causes mystery Swine Disease. We describe: 1) isolating the virus from the Disease; 2) characterizing the virus as a new enveloped RNA virus; 3) reproducing the Disease experimentally with the isolated Lelystad virus; 4) isolating the virus from the experimentally induced Disease.
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experimental reproduction of porcine epidemic abortion and respiratory syndrome mystery Swine Disease by infection with lelystad vims koch s postulates fulfilled
Veterinary Quarterly, 1991Co-Authors: C. Terpstra, G. Wensvoort, J.m.a. PolAbstract:Summary Aerosol exposure of eight pregnant sows to cell‐culture‐ propagated Lelystad virus resulted in clinical signs characteristic of so‐called mystery Swine Disease. After an incubation of 4–7 days, all sows were inappetant and listless for 6–9 days. Two sows developed a transient red‐blue discolouration of the ears ('abortus blauw’ or blue ear Disease) accompanied by abdominal respiration, and two had a fever for one day only. One sow aborted at 109 days of gestation. The other seven sows, farrowing between 113 and 117 days of gestation, gave birth to numerous mummified, dead, and weak piglets. Of these seven, the mean number of piglets born dead to each sow was 4.6 and the mean number born alive was 7.7; 3.1 piglets per sow (40%) died within the first week. Lelystad virus was isolated from 31 piglets, which were born dead or died shortly after birth. Antibody was detected in precolostral blood samples or ascitic fluids of 23 piglets, a finding which demonstrated transplacental passage of the virus in...
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pathological ultrastructural and immunohistochemical changes caused by lelystad virus in experimentally induced infections of mystery Swine Disease synonym porcine epidemic abortion and respiratory syndrome pears
Veterinary Quarterly, 1991Co-Authors: J.m.a. Pol, G. Wensvoort, J E Van Dijk, C. TerpstraAbstract:Summary The pathogenicity and pathogenesis of Lelystad virus was studied in six 6‐day‐old SPF piglets. A third passage of the agent was propagated on porcine alveolar macrophages and intranasally inoculated into pigs. Pigs were killed at hours 24, 48, 60, and 72, and on days 6 and 8 after inoculation. From day 2 on pigs developed diffuse interstitial pneumonia with focal areas of catarrhal pneumonia, and from this day on splenic red pulp macrophages were enlarged and vacuolated. Lelystad virus was re‐isolated from the lungs of infected pigs from day 2 after inoculation. Lelystad virus antigens were detected by immunohistochemical techniques in bronchiolar epithelium and alveolar cells, and in spleen cells of infected pigs from day 2 after inoculation. Ultrastructural examination of tissues by electron microscopy revealed degenerating alveolar macrophages and epithelial cells in lungs and nasal mucosa, with excessive vacuolation of the endoplasmic reticulum. Although the respiratory tract seems to be the t...
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Mystery Swine Disease in The Netherlands: the isolation of Lelystad virus.
The veterinary quarterly, 1991Co-Authors: G. Wensvoort, E.p. De Kluyver, C. Terpstra, J.m.a. Pol, E. A. Ter Laak, M. Bloemraad, C. Kragten, L Van Buiten, A. Den Besten, F. WagenaarAbstract:In early 1991, the Dutch pig-industry was struck by the so-called mystery Swine Disease. Large-scale laboratory investigations were undertaken to search for the etiological agent. We focused on isolating viruses and mycoplasmas, and we tested paired sera of affected sows for antibodies against ten known pig viruses. The mycoplasmas M. hyosynoviae, M. hyopneumoniae, and Acholeplasma laidlawii, and the viruses encephalomyocarditis virus and porcine enterovirus types 2 and 7 were isolated from individual pigs. An unknown agent, however, was isolated from 16 of 20 piglets and from 41 of 63 sows. This agent was characterised as a virus and designated Lelystad virus. No relationship between this virus and other viruses has yet been established. Of 165 sows reportedly afflicted by the Disease, 123 (75 per cent) seroconverted to Lelystad virus, whereas less than 10 per cent seroconverted to any of the other virus isolates or to the known viral pathogens. Antibodies directed against Lelystad virus were also found in pigs with mystery Swine Disease in England, Germany, and in the United States. We conclude that infection with Lelystad virus is the likely cause of mystery Swine Disease.
G. Wensvoort - One of the best experts on this subject based on the ideXlab platform.
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lelystad virus the causative agent of porcine epidemic abortion and respiratory syndrome pears is related to ldv and eav
Virology, 1993Co-Authors: J. J. M. Meulenberg, Marcel Hulst, E. J. De Meijer, P. L. J. M. Moonen, E.p. De Kluyver, G. Wensvoort, Den A Besten, R. J. M. MoormannAbstract:Abstract The genome of Lelystad virus (LV), the causative agent of porcine epidemic abortion and respiratory syndrome (previously known as mystery Swine Disease), was shown to be a polyadenylated RNA molecule. The nucleotide sequence of the LV genome was determined from a set of overlapping cDNA clones. A consecutive sequence of 15,088 nucleotides was obtained. Eight open reading frames (ORFs) that might encode virus-specific proteins were identified. ORF1a and ORF1b are predicted to encode the vital RNA polymerase because the amino acid sequence contains sequence elements that are conserved in RNA polymerases of the torovirus Berne virus (BEV), equine arteritis virus (EAV), lactate dehydrogenase-elevating virus (LDV), the coronaviruses, and other positive-strand RNA viruses. A heptanucleotide slippery sequence (UUUAAAC) and a putative pseudoknot structure, which are both required for efficient ribosomal frameshifting during translation of the RNA polymerase ORF 1b of BEV, EAV, and the coronaviruses, were identified in the overlapping region of ORF1a and ORF1b of LV. ORFs 2 to 6 probably encode viral membrane-associated proteins, whereas ORF7 is predicted to encode the nucleocapsid protein. Comparison of the amino acid sequences of the ORFs identified in the genome of LV, LDV, and EAV indicated that LV and LDV are more closely related than LV and EAV. A 3′ nested set of six subgenomic RNAs was detected in LV-infected cells. These subgenomic RNAs contain a common leader sequence that is derived from the 5′ end of the genomic RNA and that is joined to the 3′ terminal body sequence. Our results indicate that LV is closely related evolutionarily to LDV and EAV, both members of a recently proposed family of positive-strand RNA viruses, the Arteriviridae.
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Lelystad virus, the cause of porcine epidemic abortion and respiratory syndrome: a review of mystery Swine Disease research at Lelystad
Veterinary microbiology, 1992Co-Authors: G. Wensvoort, Marcel Hulst, E.p. De Kluyver, R. J. M. Moormann, J.m.a. Pol, A. Den Besten, F. Wagenaar, R. Bloemraad, T. Zetstra, C. TerpstraAbstract:This paper reviews the laboratory investigations that led us to isolate the Lelystad virus and demonstrate that this virus causes mystery Swine Disease. We describe: 1) isolating the virus from the Disease; 2) characterizing the virus as a new enveloped RNA virus; 3) reproducing the Disease experimentally with the isolated Lelystad virus; 4) isolating the virus from the experimentally induced Disease.
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experimental reproduction of porcine epidemic abortion and respiratory syndrome mystery Swine Disease by infection with lelystad vims koch s postulates fulfilled
Veterinary Quarterly, 1991Co-Authors: C. Terpstra, G. Wensvoort, J.m.a. PolAbstract:Summary Aerosol exposure of eight pregnant sows to cell‐culture‐ propagated Lelystad virus resulted in clinical signs characteristic of so‐called mystery Swine Disease. After an incubation of 4–7 days, all sows were inappetant and listless for 6–9 days. Two sows developed a transient red‐blue discolouration of the ears ('abortus blauw’ or blue ear Disease) accompanied by abdominal respiration, and two had a fever for one day only. One sow aborted at 109 days of gestation. The other seven sows, farrowing between 113 and 117 days of gestation, gave birth to numerous mummified, dead, and weak piglets. Of these seven, the mean number of piglets born dead to each sow was 4.6 and the mean number born alive was 7.7; 3.1 piglets per sow (40%) died within the first week. Lelystad virus was isolated from 31 piglets, which were born dead or died shortly after birth. Antibody was detected in precolostral blood samples or ascitic fluids of 23 piglets, a finding which demonstrated transplacental passage of the virus in...
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pathological ultrastructural and immunohistochemical changes caused by lelystad virus in experimentally induced infections of mystery Swine Disease synonym porcine epidemic abortion and respiratory syndrome pears
Veterinary Quarterly, 1991Co-Authors: J.m.a. Pol, G. Wensvoort, J E Van Dijk, C. TerpstraAbstract:Summary The pathogenicity and pathogenesis of Lelystad virus was studied in six 6‐day‐old SPF piglets. A third passage of the agent was propagated on porcine alveolar macrophages and intranasally inoculated into pigs. Pigs were killed at hours 24, 48, 60, and 72, and on days 6 and 8 after inoculation. From day 2 on pigs developed diffuse interstitial pneumonia with focal areas of catarrhal pneumonia, and from this day on splenic red pulp macrophages were enlarged and vacuolated. Lelystad virus was re‐isolated from the lungs of infected pigs from day 2 after inoculation. Lelystad virus antigens were detected by immunohistochemical techniques in bronchiolar epithelium and alveolar cells, and in spleen cells of infected pigs from day 2 after inoculation. Ultrastructural examination of tissues by electron microscopy revealed degenerating alveolar macrophages and epithelial cells in lungs and nasal mucosa, with excessive vacuolation of the endoplasmic reticulum. Although the respiratory tract seems to be the t...
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Mystery Swine Disease in The Netherlands: the isolation of Lelystad virus.
The veterinary quarterly, 1991Co-Authors: G. Wensvoort, E.p. De Kluyver, C. Terpstra, J.m.a. Pol, E. A. Ter Laak, M. Bloemraad, C. Kragten, L Van Buiten, A. Den Besten, F. WagenaarAbstract:In early 1991, the Dutch pig-industry was struck by the so-called mystery Swine Disease. Large-scale laboratory investigations were undertaken to search for the etiological agent. We focused on isolating viruses and mycoplasmas, and we tested paired sera of affected sows for antibodies against ten known pig viruses. The mycoplasmas M. hyosynoviae, M. hyopneumoniae, and Acholeplasma laidlawii, and the viruses encephalomyocarditis virus and porcine enterovirus types 2 and 7 were isolated from individual pigs. An unknown agent, however, was isolated from 16 of 20 piglets and from 41 of 63 sows. This agent was characterised as a virus and designated Lelystad virus. No relationship between this virus and other viruses has yet been established. Of 165 sows reportedly afflicted by the Disease, 123 (75 per cent) seroconverted to Lelystad virus, whereas less than 10 per cent seroconverted to any of the other virus isolates or to the known viral pathogens. Antibodies directed against Lelystad virus were also found in pigs with mystery Swine Disease in England, Germany, and in the United States. We conclude that infection with Lelystad virus is the likely cause of mystery Swine Disease.
R. J. M. Moormann - One of the best experts on this subject based on the ideXlab platform.
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lelystad virus the causative agent of porcine epidemic abortion and respiratory syndrome pears is related to ldv and eav
Virology, 1993Co-Authors: J. J. M. Meulenberg, Marcel Hulst, E. J. De Meijer, P. L. J. M. Moonen, E.p. De Kluyver, G. Wensvoort, Den A Besten, R. J. M. MoormannAbstract:Abstract The genome of Lelystad virus (LV), the causative agent of porcine epidemic abortion and respiratory syndrome (previously known as mystery Swine Disease), was shown to be a polyadenylated RNA molecule. The nucleotide sequence of the LV genome was determined from a set of overlapping cDNA clones. A consecutive sequence of 15,088 nucleotides was obtained. Eight open reading frames (ORFs) that might encode virus-specific proteins were identified. ORF1a and ORF1b are predicted to encode the vital RNA polymerase because the amino acid sequence contains sequence elements that are conserved in RNA polymerases of the torovirus Berne virus (BEV), equine arteritis virus (EAV), lactate dehydrogenase-elevating virus (LDV), the coronaviruses, and other positive-strand RNA viruses. A heptanucleotide slippery sequence (UUUAAAC) and a putative pseudoknot structure, which are both required for efficient ribosomal frameshifting during translation of the RNA polymerase ORF 1b of BEV, EAV, and the coronaviruses, were identified in the overlapping region of ORF1a and ORF1b of LV. ORFs 2 to 6 probably encode viral membrane-associated proteins, whereas ORF7 is predicted to encode the nucleocapsid protein. Comparison of the amino acid sequences of the ORFs identified in the genome of LV, LDV, and EAV indicated that LV and LDV are more closely related than LV and EAV. A 3′ nested set of six subgenomic RNAs was detected in LV-infected cells. These subgenomic RNAs contain a common leader sequence that is derived from the 5′ end of the genomic RNA and that is joined to the 3′ terminal body sequence. Our results indicate that LV is closely related evolutionarily to LDV and EAV, both members of a recently proposed family of positive-strand RNA viruses, the Arteriviridae.
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Lelystad virus, the cause of porcine epidemic abortion and respiratory syndrome: a review of mystery Swine Disease research at Lelystad
Veterinary microbiology, 1992Co-Authors: G. Wensvoort, Marcel Hulst, E.p. De Kluyver, R. J. M. Moormann, J.m.a. Pol, A. Den Besten, F. Wagenaar, R. Bloemraad, T. Zetstra, C. TerpstraAbstract:This paper reviews the laboratory investigations that led us to isolate the Lelystad virus and demonstrate that this virus causes mystery Swine Disease. We describe: 1) isolating the virus from the Disease; 2) characterizing the virus as a new enveloped RNA virus; 3) reproducing the Disease experimentally with the isolated Lelystad virus; 4) isolating the virus from the experimentally induced Disease.
