title: Influenza viruses and cross-reactivity in healthy adults: humoral and cellular immunity induced by seasonal 2007/2008 influenza vaccination against vaccine antigens and 2009 A(H1N1) pandemic influenza virus.
abstract: We analyzed humoral and cellular immune responses against vaccine antigens and the new A(H1N1) virus in healthy adults before and after immunization with the 2007/2008 commercially available trivalent subunit MF59-adjuvanted influenza vaccine during the Fall 2007, prior to the emergence of the new virus. Antibody titers were significantly boosted only against the three vaccine antigens. Seasonal vaccination boosted pre-existing cellular responses upon stimulation of peripheral blood mononuclear cells not only with the homologous three vaccine antigens, but also with the heterologous new 2009 A(H1N1) and with a highly conserved peptide present in the stalk region of hemagglutinin (HA). These results show that cross-reactive cell responses against the new virus were present before the circulation of the virus and were boosted by seasonal vaccination. The cross-reactivity of cellular responses might, at least in part, explain the low pathogenicity of the new pandemic virus. The finding of cellular immunity, that can be increased by seasonal vaccination, against the conserved HA peptide, underline the potential use, in human vaccines, of conserved peptides of the stalk region of HA characterized by broad immunogenicity in experimental systems.
authors.affiliation: Department of Medical and Surgical Specialties and Public Health, University of Perugia, Via del Giochetto, 06123 Perugia, Italy. anna@unipg.it
authors.forename: Anna M
authors.initials: AM
authors.lastname: Iorio
authors.forename: Onelia
authors.initials: O
authors.lastname: Bistoni
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Galdiero
authors.forename: Enrica
authors.initials: E
authors.lastname: Lepri
authors.forename: Barbara
authors.initials: B
authors.lastname: Camilloni
authors.forename: Anna M
authors.initials: AM
authors.lastname: Russano
authors.forename: Mariella
authors.initials: M
authors.lastname: Neri
authors.forename: Michela
authors.initials: M
authors.lastname: Basileo
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Spinozzi
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D056738:Cross Protection / Q000276:immunology*; D003429:Cross Reactions / Q000276:immunology; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control*; D007371:Interferon-gamma / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011136:Polysorbates / Q000008:administration & dosage; D013185:Squalene / Q000008:administration & dosage; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D007252:Influenza Vaccines; C089950:MF59 oil emulsion; D011136:Polysorbates; D013185:Squalene; D007371:Interferon-gamma