title: One dose of an MF59-adjuvanted pandemic A/H1N1 vaccine recruits pre-existing immune memory and induces the rapid rise of neutralizing antibodies.
abstract: Protective antibody responses to a single dose of 2009 pandemic vaccines have been observed in the majority of healthy subjects aged more than 3 years. These findings suggest that immune memory lymphocytes primed by previous exposure to seasonal influenza antigens are recruited in the response to A/H1N1 pandemic vaccines and allow rapid seroconversion. However, a clear dissection of the immune memory components favoring a fast response to pandemic vaccination is still lacking. Here we report the results from a clinical study where antibody, CD4+ T cell, plasmablast and memory B cell responses to one dose of an MF59-adjuvanted A/H1N1 pandemic vaccine were analyzed in healthy adults. While confirming the rapid appearance of antibodies neutralizing the A/H1N1 pandemic virus, we show here that the response is dominated by IgG-switched antibodies already in the first week after vaccination. In addition, we found that vaccination induces the rapid expansion of pre-existing CD4+ T cells and IgG-memory B lymphocytes cross-reactive to seasonal and pandemic A/H1N1 antigens. These data shed light on the different components of the immune response to the 2009 H1N1 pandemic influenza vaccination and may have implications in the design of vaccination strategies against future influenza pandemics.
authors.affiliation: Research Development, Novartis Vaccines and Diagnostics srl, Siena, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Faenzi
authors.forename: Luisanna
authors.initials: L
authors.lastname: Zedda
authors.forename: Monia
authors.initials: M
authors.lastname: Bardelli
authors.forename: Fabiana
authors.initials: F
authors.lastname: Spensieri
authors.forename: Erica
authors.initials: E
authors.lastname: Borgogni
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Volpini
authors.forename: Francesca
authors.initials: F
authors.lastname: Buricchi
authors.forename: Franco Laghi
authors.initials: FL
authors.lastname: Pasini
authors.forename: Pier Leopoldo
authors.initials: PL
authors.lastname: Capecchi
authors.forename: Fabio
authors.initials: F
authors.lastname: Montanaro
authors.forename: Riccardo
authors.initials: R
authors.lastname: Belli
authors.forename: Maria
authors.initials: M
authors.lastname: Lattanzi
authors.forename: Simona
authors.initials: S
authors.lastname: Piccirella
authors.forename: Emanuele
authors.initials: E
authors.lastname: Montomoli
authors.forename: Syed Sohail
authors.initials: SS
authors.lastname: Ahmed
authors.forename: Rino
authors.initials: R
authors.lastname: Rappuoli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Del Giudice
authors.forename: Oretta
authors.initials: O
authors.lastname: Finco
authors.forename: Flora
authors.initials: F
authors.lastname: Castellino
authors.forename: Grazia
authors.initials: G
authors.lastname: Galli
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000293:Adolescent; D000328:Adult; D057134:Antibodies, Neutralizing / Q000097:blood*; D000914:Antibodies, Viral / Q000097:blood*; D001402:B-Lymphocytes / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D003429:Cross Reactions; D005260:Female; D006801:Humans; D007156:Immunologic Memory; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011136:Polysorbates / Q000008:administration & dosage*; D013185:Squalene / Q000008:administration & dosage*; D014611:Vaccination / Q000379:methods; D055815:Young Adult
chemical_list: D000276:Adjuvants, Immunologic; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D007252:Influenza Vaccines; C089950:MF59 oil emulsion; D011136:Polysorbates; D013185:Squalene