Multiple epitopes from one or more viruses can be lined up and co-expressed in one vector to generate multi-epitopes DNA vaccines. In the study, four recombinant plasmids were constructed based on HA and NP gene of avian influenza virus (AIV) (H5N1): (1) pIRES/HA, carrying the complete HA gene; (2) pIRES/tHA, carrying a truncated HA gene fragment of major neutralizing antigenic epitopes; (3) pIRES/tHA-NPep, in which three CTL epitopes of NP gene of AIV were fused to the truncated HA from the C-terminal; and (4) pIRES/tHA-NPep-IFN-gamma, which was constructed by replacing neo gene in pIRES/ tHA-NPep with IFN-y of chicken. Fifty five SPF chickens were randomly divided into five groups and immunized with the above four constructs and control plasmid. Each chicken was intramuscally immunized with 200 microg plasmid DNA three times in a two-week interval. Two weeks after the third immunization, chickens were injected with H5N1 subtype avian influenza virus. Before the virus loading no detectable antibodies to HA were found in the chicken serum; but high levels of HI antibodies were detected in the serum of the survived chickens. The percentages of CD4+ and CD8+ T lymphocyte in peripheral blood of immunized chickens increased steadily after the vaccination. After virus loading all chickens in the control group died within three to eight days, and the survival rates of the four DNA vaccine groups were as follows: pIRES/HA, 54.5%; pIRES/tHA, 30%, pIRES/ tHA-NPep, 36.3%, pIRES/tHA-NPep-IFN-gamma, 50%. These results indicated that multi-epitopes DNA immunization can induce immune response and protect chickens from homologous virus loading.
Animals ; Chickens ; Epitopes ; immunology ; Influenza A Virus, H5N1 Subtype ; immunology ; pathogenicity ; Influenza in Birds ; immunology ; prevention & control ; virology ; Vaccines, DNA ; immunology

In Korea, several outbreaks of low pathogenic AI (H9N2) viral infections leading to decreased egg production and increased mortality have been reported on commercial farms since 1996, resulting in severe economic losses. To control the H9N2 LPAI endemic, the Korea Veterinary Authority has permitted the use of the inactivated H9N2 LPAI vaccine since 2007. In this study, we developed a killed vaccine using a low pathogenic H9N2 AI virus (A/chicken/Korea/ADL0401) and conducted safety and efficacy tests in commercial layer farms while focusing on analysis of factors that cause losses to farms, including egg production rate, egg abnormality, and feed efficiency. The egg production rate of the control group declined dramatically 5 days after the challenge. There were no changes in feed consumption of all three groups before the challenge, but rates of the control declined afterward. Clinical signs in the vaccinated groups were similar, and a slight decline in feed consumption was observed after challenge; however, this returned to normal more rapidly than the control group and commercial layers. Overall, the results of this study indicate that the safety and efficacy of the vaccine are adequate to provide protection against the AI field infection (H9N2) epidemic in Korea.
Animals ; Chickens ; Emulsions ; Female ; Influenza A Virus, H9N2 Subtype/*immunology ; Influenza Vaccines/*immunology/*standards ; Influenza in Birds/immunology/prevention & control ; Oviparity ; Specific Pathogen-Free Organisms ; Vaccines, Inactivated/immunology

Since 2002, H7 subtype avian influenza viruses (AIVs) have caused more than 100 human infection cases in the Netherlands, Italy, Canada, the United States, and the United Kingdom, with clinical illness ranging from conjunctivitis to mild upper respiratory illness to pneumonia. On March 31st, three fatal cases caused by infection of a novel reassortant H7N9 subtype were reported in Shanghai City and Anhui Province in China. With the ability of H7 subtype to cause severe human disease and the increasing isolation of subtype H7 AIVs, we highlighted the need for continuous surveillance in both humans and animals and characterization of these viruses for the development of vaccines and anti-viral drugs.
Animals ; Chickens ; Ducks ; Humans ; Influenza A virus ; genetics ; isolation & purification ; pathogenicity ; physiology ; Influenza Vaccines ; genetics ; immunology ; Influenza in Birds ; immunology ; prevention & control ; virology ; Influenza, Human ; immunology ; prevention & control ; virology ; Poultry Diseases ; immunology ; prevention & control ; virology ; Turkeys

Active serologic surveillance is necessary to control the spread of the avian influenza virus (AIV). In this study, we evaluated a commercially-available cELISA in terms of its ability to detect AIV antibodies in the sera of 3,358 animals from twelve species. cELISA detected antibodies against reference H1- through H15-subtype AIV strains without cross reactivity. Furthermore, the cELISA was able to detect antibodies produced following a challenge of the AIV H9N2 subtype in chickens, or following vaccination of the AIV H9 or H5 subtypes in chickens, ducks and geese. Next, we tested the sensitivity and specificity of the cELISA with sera from twelve different animal species, and compared these results with those obtained by the hemagglutination-inhibition (HI) test, the "gold standard" in AIV sera surveillance, a second commercially-available cELISA (IZS ELISA), or the agar gel precipitation (AGP) test. Compared with the HI test, the sensitivities and specificities of cELISA were 95% and 96% in chicken, 86% and 88% in duck, 97% and 100% in turkey, 100% and 87% in goose, and 91% and 97% in swine, respectively. The sensitivities and specificities of the cELISA in this study were higher than those of IZS ELISA for the duck, turkey, goose, and grey partridge sera samples. The results of AGP test against duck and turkey sera also showed significant correlation with the results of cELISA (R-value >0.9). In terms of flock sensitivity, the cELISA correlated better with the HI test than with commercially-available indirect ELISAs, with 100% flock sensitivity.
Animals ; Antibodies, Viral/*blood ; Birds ; Enzyme-Linked Immunosorbent Assay/methods/*veterinary ; Horses ; Influenza A virus/*immunology ; Influenza Vaccines/immunology ; Influenza in Birds/blood/*immunology/prevention & control ; Sensitivity and Specificity ; Serologic Tests ; Species Specificity ; Swine

Avian influenza has emerged as one of the primary public health concern of the 21st century. Influenza strain H5N1 is capable of incidentally infecting humans and other mammals. Since their reemergence in 2003, highly pathogenic avian influenza A (H5N1) viruses have been transmitted from poultry to humans (by direct or indirect contact with infected birds) in several provinces of Mainland China, which has resulted in 22 cases of human infection and has created repercussions for the Chinese economy. People have been concerned whether a new pandemic will occur in the future. The eradication of pathogenic avian influenza viruses appears to be the most effective way to prevent an influenza pandemic. This paper will examine the features of H5N1, including incidence, infection, immunity, clinical management, prevention and control, and therapy in Mainland China.
Adolescent ; Adult ; Animals ; Birds ; Child ; China/epidemiology ; Disease Outbreaks/prevention & control ; Female ; Humans ; Incidence ; *Influenza A Virus, H5N1 Subtype ; Influenza in Birds/prevention & control ; Influenza, Human/*epidemiology/immunology/therapy ; Male ; Zoonoses/epidemiology/transmission/virology

Highly pathogenic avian influenza A (HPAI) viruses of the H5N1 subtypes caused enormous economical loss to poultry farms in China and Southeastern Asian countries. The vaccination program is a reliable strategy in controlling the prevalence of these disastrous diseases. The six internal genes of the high-yield influenza virus A/Goose/Dalian/3/01 (H9N2), the hemagglutinin (HA) gene of A/Goose/HLJ/QFY/04 (H5N1) strain, and the neuraminidase gene from A/Duck/Germany/1215/73 (H2N3) reference strain were amplified by RT-PCR technique. The HA gene was modified by the deletion of four basic amino acids of the connecting peptide between HA1 and HA2. Eight gene expressing plasmids were constructed, and the recombinant virus rH5N3 was generated by cells transfection. The infection of chicken embryos and the challenge tests involving chickens demonstrated that the recombinant H5N3 (rH5N3) influenza virus is avirulent. The allantoic fluids of rH5N3-infected eggs contain high-titer influenza viruses with hemagglutination unit of 1:2048, which are eight times those of the parental H5N1 virus. The rH5N3 oil-emulsified vaccine could induce hemagglutination inhibition (HI) antibodies in chickens in 2 weeks post-vaccination, and maximum geometric mean HI-titer were observed 4 approximately 5 weeks post-vaccination and were kept under observation for 18 weeks. The rH5N3-vaccinated chickens were fully protected against morbidity and mortality of the lethal challenge of the H5N1 HPAI viruses, A/Goose/Guangdong/1/96 and A/Goose/HLJ/QFY/04, which had 8 years expansion and differences among multiple amino acids in HA protein. The N3 neuraminidase protein marker makes it possible to distinguish between H5N1 infected- and H5N3 vaccinated animals.
Animals ; Chick Embryo ; Chickens ; Hemagglutination Inhibition Tests ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; immunology ; Influenza A Virus, H5N1 Subtype ; immunology ; Influenza Vaccines ; immunology ; Influenza in Birds ; prevention & control ; Plasmids ; Vaccines, Synthetic ; immunology

OBJECTIVETo prepare the 4 candidate vaccine strains of H5N1 avian influenza virus isolated in China.

METHODSRecombinant viruses were rescued using reverse genetics. Neuraminidase (NA) and hemagglutinin (HA) segments of the A/Xinjiang/1/2006, A/Guangxi/1/2009, A/Hubei/1/2010, and A/Guangdong/1/2011 viruses were amplified by RT-PCR. Multibasic amino acid cleavage site of HA was removed and ligated into the pCIpolI vector for virus rescue. The recombinant viruses were evaluated by trypsin dependent assays. Their embryonate survival and antigenicity were compared with those of the respective wild-type viruses.

RESULTSThe 4 recombinant viruses showed similar antigenicity compared with wild-type viruses, chicken embryo survival and trypsin-dependent characteristics.

CONCLUSIONThe 4 recombinant viruses rescued using reverse genetics meet the criteria for classification of low pathogenic avian influenza strains, thus supporting the use of them for the development of seeds and production of pre-pandemic vaccines.

Animals ; Chick Embryo ; Chickens ; China ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; metabolism ; Influenza A Virus, H5N1 Subtype ; immunology ; Influenza Vaccines ; immunology ; Influenza in Birds ; prevention & control ; virology ; Neuraminidase ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Vaccines, Synthetic ; immunology

The H9N2 subtype low pathogenic avian influenza is one of the most prevalent avian diseases worldwide, and was first documented in 1996 in Korea. This disease caused serious economic loss in Korea's poultry industry. In order to develop an oil-based inactivated vaccine, a virus that had been isolated in 2001 (A/chicken/Korea/01310/ 2001) was selected based on its pathogenic, antigenic, and genetic properties. However, in animal experiments, the efficacy of the vaccine was found to be very low without concentration of the antigen (2(7) to 2(10) hemagglutinin unit). In order to overcome the low productivity, we passaged the vaccine candidate virus to chicken eggs. After the 20th passage, the virus was approximately ten times more productive compared with the parent virus. For the most part, the passaged virus maintained the hemagglutinin cleavage site amino acid motif (PATSGR/GLF) and had only three amino acid changes (T133N, V216G, E439D, H3 numbering) in the hemagglutinin molecule, as well as 18 amino acid deletions (55-72) and one amino acid change (E54D) in the NA stalk region. The amino acid changes did not significantly affect the antigenicity of the vaccine virus when tested by hemagglutination inhibition assay. Though not complete, the vaccine produced after the 20th passage of the virus (01310 CE20) showed good protection against a homologous and recent Korean isolate (A/chicken/Korea/Q30/2004) in specific pathogen- free chickens. The vaccine developed in this study would be helpful for controlling the H9N2 LPAI in Korea.
Animals ; Chickens ; Gene Expression Regulation, Viral ; Hemagglutinins/genetics ; Influenza A Virus, H9N2 Subtype/*immunology/pathogenicity ; Influenza Vaccines/*immunology ; Influenza in Birds/epidemiology/*prevention & control/*virology ; Korea/epidemiology ; Neuraminidase/genetics ; Specific Pathogen-Free Organisms ; Time Factors ; Vaccines, Inactivated/*immunology

In order to control the H9N2 subtype low pathogenic avian influenza (LPAI), an inactivated vaccine has been used in Korea since 2007. The Korean veterinary authority permitted the use of a single H9N2 LPAI vaccine strain to simplify the evolution of the circulating virus due to the immune pressure caused by the vaccine use. It is therefore important to determine the suitability of the vaccine strain in the final inactivated oil emulsion LPAI vaccine. In this study, we applied molecular rather than biological methods to verify the suitability of the vaccine strain used in commercial vaccines and successfully identified the strain by comparing the nucleotide sequences of the hemagglutinin and neuraminidase genes with that of the permitted Korean LPAI vaccine strain. It is thought that the method used in this study might be successfully applied to other viral genes of the LPAI vaccine strain and perhaps to other veterinary oil emulsion vaccines.
Animals ; Base Sequence ; Birds ; DNA, Viral/chemistry/genetics ; Hemagglutinin Glycoproteins, Influenza Virus/chemistry/genetics ; Influenza A Virus, H9N2 Subtype/genetics/*immunology ; Influenza Vaccines/genetics/*immunology ; Influenza in Birds/*immunology/prevention & control/virology ; Molecular Sequence Data ; Neuraminidase/chemistry/genetics ; Polymerase Chain Reaction/veterinary ; Republic of Korea ; Sequence Alignment ; Vaccines, Inactivated/genetics/immunology

Animals ; Antiviral Agents ; administration & dosage ; therapeutic use ; Birds ; China ; Communicable Disease Control ; Disaster Planning ; methods ; organization & administration ; Disease Outbreaks ; prevention & control ; Global Health ; Humans ; Influenza A Virus, H5N1 Subtype ; immunology ; Influenza Vaccines ; administration & dosage ; therapeutic use ; Influenza in Birds ; epidemiology ; prevention & control ; transmission ; virology ; Influenza, Human ; epidemiology ; prevention & control ; transmission ; virology ; Poultry ; Vaccination