title: DNA vaccination elicits protective immune responses against pandemic and classic swine influenza viruses in pigs.
abstract: Swine influenza is a highly contagious viral infection in pigs that significantly impacts the pork industry due to weight loss and secondary infections. There is also the potential of a significant threat to public health, as was seen in 2009 when the pandemic H1N1 influenza virus strain emerged from reassortment events among avian, swine, and human influenza viruses within pigs. As classic and pandemic H1N1 strains now circulate in swine, an effective vaccine may be the best strategy to protect the pork industry and public health. Current inactivated-virus vaccines available for swine influenza protect only against viral strains closely related to the vaccine strain, and egg-based production of these vaccines is insufficient to respond to large outbreaks. DNA vaccines are a promising alternative since they can potentially induce broad-based protection with more efficient production methods. In this study we evaluated the potentials of monovalent and trivalent DNA vaccine constructs to (i) elicit both humoral and gamma interferon (IFN-γ) responses and (ii) protect pigs against viral shedding and lung disease after challenge with pandemic H1N1 or classic swine H1N1 influenza virus. We also compared the efficiency of a needle-free vaccine delivery method to that of a conventional needle/syringe injection. We report that DNA vaccination elicits robust serum antibody and cellular responses after three immunizations and confers significant protection against influenza virus challenge. Needle-free delivery elicited improved antibody responses with the same efficiency as conventional injection and should be considered for development as a practical alternative for vaccine administration.
authors.affiliation: Laboratory Animal Medicine, Vaccine Research Center, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: J Patrick
authors.initials: JP
authors.lastname: Gorres
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Lager
authors.forename: Wing-Pui
authors.initials: WP
authors.lastname: Kong
authors.forename: Michael
authors.initials: M
authors.lastname: Royals
authors.forename: John-Paul
authors.initials: JP
authors.lastname: Todd
authors.forename: Amy L
authors.initials: AL
authors.lastname: Vincent
authors.forename: Chih-Jen
authors.initials: CJ
authors.lastname: Wei
authors.forename: Crystal L
authors.initials: CL
authors.lastname: Loving
authors.forename: Eraldo L
authors.initials: EL
authors.lastname: Zanella
authors.forename: Bruce
authors.initials: B
authors.lastname: Janke
authors.forename: Marcus E
authors.initials: ME
authors.lastname: Kehrli
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Nabel
authors.forename: Srinivas S
authors.initials: SS
authors.lastname: Rao
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral / Q000097:blood; D006385:Hemagglutination Inhibition Tests; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007371:Interferon-gamma / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008168:Lung / Q000473:pathology / Q000821:virology; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D014611:Vaccination / Q000379:methods*; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology*; D019562:Viral Load; D017201:Virus Shedding
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D007252:Influenza Vaccines; D019444:Vaccines, DNA; D007371:Interferon-gamma