title: A reassortment-incompetent live attenuated influenza virus vaccine for protection against pandemic virus strains.
abstract: Although live-attenuated influenza vaccines (LAIV) are safe for use in protection against seasonal influenza strains, concerns regarding their potential to reassort with wild-type virus strains have been voiced. LAIVs have been demonstrated to induce enhanced mucosal and cell-mediated immunity better than inactivated vaccines while also requiring a smaller dose to achieve a protective immune response. To address the need for a reassortment-incompetent live influenza A virus vaccine, we have designed a chimeric virus that takes advantage of the fact that influenza A and B viruses do not reassort. Our novel vaccine prototype uses an attenuated influenza B virus that has been manipulated to express the ectodomain of the influenza A hemagglutinin protein, the major target for eliciting neutralizing antibodies. The hemagglutinin RNA segment is modified such that it contains influenza B packaging signals, and therefore it cannot be incorporated into a wild-type influenza A virus. We have applied our strategy to different influenza A virus subtypes and generated chimeric B/PR8 HA (H1), HK68 (H3), and VN (H5) viruses. All recombinant viruses were attenuated both in vitro and in vivo, and immunization with these recombinant viruses protected mice against lethal influenza A virus infection. Overall, our data indicate that the chimeric live-attenuated influenza B viruses expressing the modified influenza A hemagglutinin are effective LAIVs.
authors.affiliation: Department of Microbiology, Mount Sinai School of Medicine, One Gustave Levy Place, New York, NY 10029-6574, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Hai
authors.forename: Adolfo
authors.initials: A
authors.lastname: García-Sastre
authors.forename: David E
authors.initials: DE
authors.lastname: Swayne
authors.forename: Peter
authors.initials: P
authors.lastname: Palese
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D009980:Influenza A virus / Q000145:classification / Q000276:immunology*; D009981:Influenza B virus / Q000145:classification / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016865:Reassortant Viruses / Q000276:immunology*
chemical_list: D007252:Influenza Vaccines