title: Factors affecting the yield of cold-adapted influenza virus vaccine.
abstract: Various manipulations to production procedures have been investigated in order to discover methods to attain adequate or augmented titers of cold-adapted influenza virus (CAIV) vaccine. The methods modified include those used for reassortant selection and the determination of virus growth parameters. Increased infectivity titers were achieved through selection of high-yielding mutants by isolating multiple plaques during plaque purification of reassortant clones, as well as through optimization of egg incubation times, age, and lot for individual strains. Up to 6-fold increases in virus yield were obtained by selecting high yielding mutants, up to 9-fold increases were achieved by modifying egg incubation times, and a nearly 1 log increase was realized by determining the ideal egg age for individual strains.
authors.affiliation: Wyeth-Ayerst Research, Vaccine Preclinical Development Subdivision, Radnor, PA 19087, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Yannarell
authors.forename: R N
authors.initials: RN
authors.lastname: Hjorth
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens; D003080:Cold Temperature; D004285:Dogs; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000378:metabolism; D006801:Humans; D009980:Influenza A virus / Q000254:growth & development*; D007252:Influenza Vaccines; D009154:Mutation; D010948:Viral Plaque Assay
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines