title: Identification of mutations in a candidate dengue 4 vaccine strain 341750 PDK20 and construction of a full-length cDNA clone of the PDK20 vaccine candidate.
abstract: Dengue 4 virus strain 341750 serially passaged 20 times in primary dog kidney (PDK) cells was shown to have reduced infectivity for rhesus monkeys but was immunogenic and protected the monkeys from challenge with low passage parent dengue 4 virus. The dengue 4 PDK20 virus was also shown to be attenuated for human volunteers. We compared the genomic nucleotide sequences of low passage parent and PDK20 attenuated vaccine strains and identified 11 nucleotide (nt) substitutions in the PDK20 genome. Five mutations caused amino acid changes in viral proteins E (N366N/S), NS1 (E146Q), NS4B (S/L112L and A240V), and NS5 (F/L790L). Silent mutations occurred in genes encoding NS1 (nt 2609), NS3 (nt 6113, 6230 and 6239) and NS5 (nt 8081 and 8588). A full-length cDNA clone of the dengue 4 strain 341750 PDK20 was constructed and RNA transcripts of the clone were infectious in monkey kidney (LLC-MK(2)) and Aedes albopictus (C6/36) cells. The sequence analysis and availability of an infectious clone provide molecular tools to investigate the basis for the attenuation of dengue 4 virus.
authors.affiliation: Department of Virus Diseases, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA. eileen.kelly@amedd.army.mil
authors.forename: Eileen P
authors.initials: EP
authors.lastname: Kelly
authors.forename: Beena
authors.initials: B
authors.lastname: Puri
authors.forename: Wellington
authors.initials: W
authors.lastname: Sun
authors.forename: Barry
authors.initials: B
authors.lastname: Falgout
mesh_terms: D000330:Aedes; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004252:DNA Mutational Analysis; D018076:DNA, Complementary / Q000235:genetics*; D003715:Dengue / Q000473:pathology / Q000662:veterinary / Q000821:virology; D053059:Dengue Vaccines / Q000235:genetics* / Q000276:immunology*; D003716:Dengue Virus / Q000235:genetics* / Q000276:immunology*; D004285:Dogs; D006805:Human Experimentation; D006801:Humans; D008253:Macaca mulatta; D008969:Molecular Sequence Data; D008992:Monkey Diseases / Q000473:pathology / Q000821:virology; D020125:Mutation, Missense; D012367:RNA, Viral / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012692:Serial Passage; D014613:Vaccines, Attenuated / Q000235:genetics / Q000276:immunology; D014774:Virulence
chemical_list: D018076:DNA, Complementary; D053059:Dengue Vaccines; D012367:RNA, Viral; D014613:Vaccines, Attenuated