The very virulent infectious bursal disease virus (vvIBDV) strain Gx was isolated from a poutl-try farm in Guangxi Province, China, during 1996. The mortality in the infected flock was 80% and occurred 5 days after im...The very virulent infectious bursal disease virus (vvIBDV) strain Gx was isolated from a poutl-try farm in Guangxi Province, China, during 1996. The mortality in the infected flock was 80% and occurred 5 days after immunization with serotype I IBD vaccine. The results of antigen-capture ELISA (AC-ELISA), pathogenicity testing, cloning and sequence analysis of the VP2 gene showed that the deduced amino acid sequence of strain Gx VP2 was the same as vvIBDV UK661, which is considered as a reference strain for European vvIBDVs. The antigenicity of the Gx strain was the same as an European vvIBDV strain 849. The EID50 of Gx virus was 10-8.25/0. 2 ml, and the mortality was 64% when 4 week-old SPF chickens were challenged at dosage of 2×10~3EID50. We have demonstrated that the IBDV strain Gx isolated in China is vvIBDV according to European standards.展开更多
The antigenic variation of influenza A virus hemagglutinin (HA) glycoproteins requires frequent changes in vaccine formulation. The new strategy of creating influenza seed strains for vaccine production is to generate...The antigenic variation of influenza A virus hemagglutinin (HA) glycoproteins requires frequent changes in vaccine formulation. The new strategy of creating influenza seed strains for vaccine production is to generate 7 + 1 reassortants that contain seven genes from a high-yield virus A/Puerto Rico/8/34[A/PR/8/34](H1N1) and the HA gene from the circulating strains. By using this DNA-based cotransfection technique, we generated 7 + 1 reassortants rgH3N1 which had the antigenic determinants of influenza virus A/Songbird/HongKong/102/00[SB/HK/01](H3N8) and 7 other genes from A/PR/ 8/34. The hemagglutinin of A/Songbird/HongKong/102/00 is 96.3% homologous to that of A/Equine/Jilin/98[Eq/Jl/89] (H3N8). The resulting virus rgH3N1 grows to high HA titers in chicken embryonated eggs, allowing vaccine preparation in unconcentrated allantoic fluid. The rgH3N1 is stable after multiple passages in embryonated eggs. The reassortant rgH3N1 virus could be used as vaccine candidate to reduce the reemergence of equine influenza outbreaks.展开更多
A recombinant fowlpox virus co-expressing Haemagglutinin (HA) and Neuraminidase (NA)named as rFPV-HA-NA was produced by HA and NA gene of A/Goose/Guangdong/3/96(H5N1)isolate of avian influenza virus recombined into th...A recombinant fowlpox virus co-expressing Haemagglutinin (HA) and Neuraminidase (NA)named as rFPV-HA-NA was produced by HA and NA gene of A/Goose/Guangdong/3/96(H5N1)isolate of avian influenza virus recombined into the genome of fowlpox virus. In thisstudy, to evaluate its ability of protecting chickens against challenge with a lethaldose of highly pathogenic isolates of avian influenza virus, eight-week-old specific-pathogenic-free (SPF) chickens were vaccinated with recombinant virus or the wildtypefowlpox virus by wing-web puncture. After challenge 4 weeks with 10 LD50 highly pathogenicavian influenza virus H5N1 and H7N1 isolate, all chickens vaccinated with recombinantvirus were protected, while the chickens vaccinated with the wildtype fowlpox virus orunvaccinated controls experienced 100% mortality respectively following challenge. Thiscomplete protection was accompanied by the high levels of specific antibody response tothe respective components of the recombinant virus.展开更多
Porcine parvovirus (PPV) is one of the major agents causing swine reproductive failure. NS1 protein is a non-structural protein of PPV and can be used as a reagent for differentiation of vaccinated animals and infecte...Porcine parvovirus (PPV) is one of the major agents causing swine reproductive failure. NS1 protein is a non-structural protein of PPV and can be used as a reagent for differentiation of vaccinated animals and infected ones. In present study, a recombinant plasmid pET28a/NS1 was constructed by cloning the coding sequence for NS1 of PPV into pET28a, a bacterial expression vector. The NS1 protein was expressed in E. coli BL21(DE3) after induced by IPTG and the recombinant fusion protein was purified with affinity chromatography. Expression amount of NS1 protein was improved by optimizing the inducing parameters. The recombinant NS1 protein is reactive to PPV positive sera in Western blot and ELISA test and therefore can be applicable in differential diagnosis of PPV infections.展开更多
文摘The very virulent infectious bursal disease virus (vvIBDV) strain Gx was isolated from a poutl-try farm in Guangxi Province, China, during 1996. The mortality in the infected flock was 80% and occurred 5 days after immunization with serotype I IBD vaccine. The results of antigen-capture ELISA (AC-ELISA), pathogenicity testing, cloning and sequence analysis of the VP2 gene showed that the deduced amino acid sequence of strain Gx VP2 was the same as vvIBDV UK661, which is considered as a reference strain for European vvIBDVs. The antigenicity of the Gx strain was the same as an European vvIBDV strain 849. The EID50 of Gx virus was 10-8.25/0. 2 ml, and the mortality was 64% when 4 week-old SPF chickens were challenged at dosage of 2×10~3EID50. We have demonstrated that the IBDV strain Gx isolated in China is vvIBDV according to European standards.
文摘The antigenic variation of influenza A virus hemagglutinin (HA) glycoproteins requires frequent changes in vaccine formulation. The new strategy of creating influenza seed strains for vaccine production is to generate 7 + 1 reassortants that contain seven genes from a high-yield virus A/Puerto Rico/8/34[A/PR/8/34](H1N1) and the HA gene from the circulating strains. By using this DNA-based cotransfection technique, we generated 7 + 1 reassortants rgH3N1 which had the antigenic determinants of influenza virus A/Songbird/HongKong/102/00[SB/HK/01](H3N8) and 7 other genes from A/PR/ 8/34. The hemagglutinin of A/Songbird/HongKong/102/00 is 96.3% homologous to that of A/Equine/Jilin/98[Eq/Jl/89] (H3N8). The resulting virus rgH3N1 grows to high HA titers in chicken embryonated eggs, allowing vaccine preparation in unconcentrated allantoic fluid. The rgH3N1 is stable after multiple passages in embryonated eggs. The reassortant rgH3N1 virus could be used as vaccine candidate to reduce the reemergence of equine influenza outbreaks.
文摘A recombinant fowlpox virus co-expressing Haemagglutinin (HA) and Neuraminidase (NA)named as rFPV-HA-NA was produced by HA and NA gene of A/Goose/Guangdong/3/96(H5N1)isolate of avian influenza virus recombined into the genome of fowlpox virus. In thisstudy, to evaluate its ability of protecting chickens against challenge with a lethaldose of highly pathogenic isolates of avian influenza virus, eight-week-old specific-pathogenic-free (SPF) chickens were vaccinated with recombinant virus or the wildtypefowlpox virus by wing-web puncture. After challenge 4 weeks with 10 LD50 highly pathogenicavian influenza virus H5N1 and H7N1 isolate, all chickens vaccinated with recombinantvirus were protected, while the chickens vaccinated with the wildtype fowlpox virus orunvaccinated controls experienced 100% mortality respectively following challenge. Thiscomplete protection was accompanied by the high levels of specific antibody response tothe respective components of the recombinant virus.
文摘Porcine parvovirus (PPV) is one of the major agents causing swine reproductive failure. NS1 protein is a non-structural protein of PPV and can be used as a reagent for differentiation of vaccinated animals and infected ones. In present study, a recombinant plasmid pET28a/NS1 was constructed by cloning the coding sequence for NS1 of PPV into pET28a, a bacterial expression vector. The NS1 protein was expressed in E. coli BL21(DE3) after induced by IPTG and the recombinant fusion protein was purified with affinity chromatography. Expression amount of NS1 protein was improved by optimizing the inducing parameters. The recombinant NS1 protein is reactive to PPV positive sera in Western blot and ELISA test and therefore can be applicable in differential diagnosis of PPV infections.
