title: Genetic engineering of live attenuated influenza viruses.
abstract: The first live attenuated influenza vaccine (LAIV) was licensed in the USA in 2003; it is a trivalent vaccine composed of two type A (H1N1 and H3N2) and one type B influenza virus each at 10(7) fluorescent focus units (FFU). Each influenza vaccine strain is a reassortant virus that contains the hemagglutinin (HA) and neuraminidase (NA) gene segments from a wild-type influenza virus and the six internal protein gene segments from a master donor virus (MDV) of either cold-adapted A/Ann Arbor/6/60 or B/Ann Arbor/1/66. MDV confers the cold-adapted, temperature-sensitive, and attenuation phenotypes to the vaccine strains. The reassortant vaccine seeds are currently produced by reverse genetics and amplified in specific pathogen-free (SPF) 9-11 days old embryonated chicken eggs for manufacture. In addition, MDCK cell culture manufacture processes have been developed to produce LAIV for research use and with modifications for clinical and/or commercial grade material production.
authors.affiliation: MedImmune, Mountain View, CA, USA. jinh@medimmune.com
authors.forename: Hong
authors.initials: H
authors.lastname: Jin
authors.forename: Zhongying
authors.initials: Z
authors.lastname: Chen
authors.forename: Jonathan
authors.initials: J
authors.lastname: Liu
authors.forename: George
authors.initials: G
authors.lastname: Kemble
mesh_terms: D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D003080:Cold Temperature; D016895:Culture Media, Serum-Free; D004285:Dogs; D005818:Genetic Engineering / Q000379:methods; D006388:Hemagglutinins / Q000235:genetics* / Q000276:immunology; D006801:Humans; D007252:Influenza Vaccines / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D009439:Neuraminidase / Q000235:genetics* / Q000276:immunology; D009975:Orthomyxoviridae / Q000235:genetics* / Q000276:immunology; D010957:Plasmids; D016865:Reassortant Viruses / Q000235:genetics* / Q000276:immunology; D059386:Reverse Genetics / Q000379:methods; D014613:Vaccines, Attenuated; D014764:Viral Proteins / Q000235:genetics* / Q000276:immunology; D014779:Virus Replication
chemical_list: D016895:Culture Media, Serum-Free; D006388:Hemagglutinins; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated; D014764:Viral Proteins; D009439:Neuraminidase