title: Pseudoparticle neutralization is a reliable assay to measure immunity and cross-reactivity to H5N1 influenza viruses.
abstract: The standard serological methods present limitations for the measurement of immunity against H5N1 influenza strains. The hemagglutination inhibition (HI) assay lacks sensitivity and requires standardization, while the viral micro-neutralization (MN) assay needs handling of live virus. We produced pseudoparticles expressing hemagglutinin from clades 1 or 2 H5N1 in order to measure neutralizing antibodies in human sera after prime-boost vaccination with plain or MF59-adjuvanted H5N1 clade 1 subunit vaccines. Titers measured by pseudoparticle neutralization (PPN) assay significantly correlated with those measured by HI, single radial haemolysis or MN, with a PPN titer of 1:357 corresponding to an MN titer of 1:80. Notably, results from the PPN assay, confirm that MF59-H5N1 vaccine induces potent and long-lasting neutralizing antibody responses not only against the vaccine strain, but also against several heterologous clade 2 strains. Overall, the PPN assay represents a valid alternative to conventional serological methods for the evaluation of H5N1 vaccine immunogenicity.
authors: Novartis Vaccines, Siena, Italy.
authors: Isabella
authors: I
authors: Alberini
authors: Elena
authors: E
authors: Del Tordello
authors: Alba
authors: A
authors: Fasolo
authors: Nigel J
authors: NJ
authors: Temperton
authors: Grazia
authors: G
authors: Galli
authors: Chiara
authors: C
authors: Gentile
authors: Emanuele
authors: E
authors: Montomoli
authors: Anne K
authors: AK
authors: Hilbert
authors: Angelika
authors: A
authors: Banzhoff
authors: Giuseppe
authors: G
authors: Del Giudice
authors: John J
authors: JJ
authors: Donnelly
authors: Rino
authors: R
authors: Rappuoli
authors: Barbara
authors: B
authors: Capecchi
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000097:blood*; D003429:Cross Reactions; D006385:Hemagglutination Inhibition Tests; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology*; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control*; D009500:Neutralization Tests
chemical_list: D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines