title: Improved immune responses against avian influenza virus following oral vaccination of chickens with HA DNA vaccine using attenuated Salmonella typhimurium as carrier.
abstract: This study evaluates the immune responses of single avian influenza virus (AIV) HA DNA vaccine immunization using attenuated Salmonella enterica sv. Typhimurium as an oral vaccine carrier and intramuscular (IM) DNA injection. One-day-old specific-pathogen-free (SPF) chicks immunized once by oral gavage with 10(9) Salmonella colony-forming units containing plasmid expression vector encoding the HA gene of A/Ck/Malaysia/5858/04 (H5N1) (pcDNA3.1.H5) did not show any clinical manifestations. Serum hemagglutination inhibition (HI) titer samples collected from the IM immunized chickens were low compared to those immunized with S. typhimurium.pcDNA3.1.H5. The highest average antibody titers were detected on day 35 post immunization for both IM and S. typhimurium.pcDNA3.1.H5 immunized groups, at 4.0±2.8 and 51.2±7.5, respectively. S. typhimurium.pcDNA3.1.H5 also elicited both CD4(+) and CD8(+) T cells from peripheral blood mononuclear cells (PBMCs) of immunized chickens as early as day 14 after immunization, at 20.5±2.0 and 22.9±1.9%, respectively. Meanwhile, the CD4(+) and CD8(+) T cells in chickens vaccinated intramuscularly were low at 5.9±0.9 and 8.5±1.3%, respectively. Immunization of chickens with S. typhimurium.pcDNA3.1.H5 enhanced IL-1β, IL-12β, IL-15 and IL-18 expressions in spleen although no significant differences were recorded in chickens vaccinated via IM and orally with S. typhimurium and S. typhimurium.pcDNA3.1. Hence, single oral administrations of the attenuated S. typhimurium containing pcDNA3.1.H5 showed antibody, T cell and Th1-like cytokine responses against AIV in chickens. Whether the T cell response induced by vaccination is virus-specific and whether vaccination protects against AIV infection requires further study.
authors.affiliation: Institute of Bioscience, University Putra Malaysia, Serdang 43400, Selangor, Malaysia.
authors.forename: Seyed Davoud
authors.initials: SD
authors.lastname: Jazayeri
authors.forename: Aini
authors.initials: A
authors.lastname: Ideris
authors.forename: Zunita
authors.initials: Z
authors.lastname: Zakaria
authors.forename: Swee Keong
authors.initials: SK
authors.lastname: Yeap
authors.forename: Abdul Rahman
authors.initials: AR
authors.lastname: Omar
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000917:Antibody Formation; D058491:Bacterial Load; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology; D002645:Chickens / Q000276:immunology; D004279:DNA, Viral / Q000008:administration & dosage / Q000276:immunology; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D005585:Influenza in Birds / Q000276:immunology / Q000517:prevention & control*; D010957:Plasmids / Q000235:genetics; D012486:Salmonella typhimurium / Q000276:immunology; D013154:Spleen / Q000276:immunology / Q000821:virology; D013997:Time Factors; D014162:Transfection; D014611:Vaccination / Q000379:methods / Q000662:veterinary; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D004279:DNA, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D019444:Vaccines, DNA; C109963:hemagglutinin, avian influenza A virus