title: Synergistic attenuation of vesicular stomatitis virus by combination of specific G gene truncations and N gene translocations.
abstract: A variety of rational approaches to attenuate growth and virulence of vesicular stomatitis virus (VSV) have been described previously. These include gene shuffling, truncation of the cytoplasmic tail of the G protein, and generation of noncytopathic M gene mutants. When separately introduced into recombinant VSV (rVSV), these mutations gave rise to viruses distinguished from their "wild-type" progenitor by diminished reproductive capacity in cell culture and/or reduced cytopathology and decreased pathogenicity in vivo. However, histopathology data from an exploratory nonhuman primate neurovirulence study indicated that some of these attenuated viruses could still cause significant levels of neurological injury. In this study, additional attenuated rVSV variants were generated by combination of the above-named three distinct classes of mutation. The resulting combination mutants were characterized by plaque size and growth kinetics in cell culture, and virulence was assessed by determination of the intracranial (IC) 50% lethal dose (LD(50)) in mice. Compared to virus having only one type of attenuating mutation, all of the mutation combinations examined gave rise to virus with smaller plaque phenotypes, delayed growth kinetics, and 10- to 500-fold-lower peak titers in cell culture. A similar pattern of attenuation was also observed following IC inoculation of mice, where differences in LD(50) of many orders of magnitude between viruses containing one and two types of attenuating mutation were sometimes seen. The results show synergistic rather than cumulative increases in attenuation and demonstrate a new approach to the attenuation of VSV and possibly other viruses.
authors.affiliation: Wyeth Vaccines Discovery Research, 401 N. Middletown Road, Bldg. 180/267, Pearl River, NY 10965, USA. clarked3@wyeth.com
authors.forename: David K
authors.initials: DK
authors.lastname: Clarke
authors.forename: Farooq
authors.initials: F
authors.lastname: Nasar
authors.forename: Margaret
authors.initials: M
authors.lastname: Lee
authors.forename: J Erik
authors.initials: JE
authors.lastname: Johnson
authors.forename: Kevin
authors.initials: K
authors.lastname: Wright
authors.forename: Priscilla
authors.initials: P
authors.lastname: Calderon
authors.forename: Min
authors.initials: M
authors.lastname: Guo
authors.forename: Robert
authors.initials: R
authors.lastname: Natuk
authors.forename: David
authors.initials: D
authors.lastname: Cooper
authors.forename: R Michael
authors.initials: RM
authors.lastname: Hendry
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Udem
mesh_terms: D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D006224:Cricetinae; D005260:Female; D017353:Gene Deletion; D005814:Genes, Viral / Q000235:genetics; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D019590:Nucleocapsid Proteins / Q000235:genetics; D018353:Rhabdoviridae Infections / Q000821:virology*; D014709:Vero Cells; D014721:Vesicular stomatitis Indiana virus / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D014759:Viral Envelope Proteins / Q000235:genetics*; D014763:Viral Matrix Proteins / Q000235:genetics; D014774:Virulence; D014779:Virus Replication
chemical_list: C028391:G protein, vesicular stomatitis virus; C094460:M protein, Vesicular stomatitis virus; D008562:Membrane Glycoproteins; D019590:Nucleocapsid Proteins; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins