title: Short interfering RNA confers intracellular antiviral immunity in human cells.
abstract: Gene silencing mediated by double-stranded RNA (dsRNA) is a sequence-specific, highly conserved mechanism in eukaryotes. In plants, it serves as an antiviral defence mechanism. Animal cells also possess this machinery but its specific function is unclear. Here we demonstrate that dsRNA can effectively protect human cells against infection by a rapidly replicating and highly cytolytic RNA virus. Pre-treatment of human and mouse cells with double-stranded, short interfering RNAs (siRNAs) to the poliovirus genome markedly reduces the titre of virus progeny and promotes clearance of the virus from most of the infected cells. The antiviral effect is sequence-specific and is not attributable to either classical antisense mechanisms or to interferon and the interferon response effectors protein kinase R (PKR) and RNaseL. Protection is the result of direct targeting of the viral genome by siRNA, as sequence analysis of escape virus (resistant to siRNAs) reveals one nucleotide substitution in the middle of the targeted sequence. Thus, siRNAs elicit specific intracellular antiviral resistance that may provide a therapeutic strategy against human viruses.
authors.affiliation: Department of Microbiology and Immunology, Box 0414 and Program in Neuroscience, University of California, San Francisco, California 94143-0414, USA.
authors.forename: Leonid
authors.initials: L
authors.lastname: Gitlin
authors.forename: Sveta
authors.initials: S
authors.lastname: Karelsky
authors.forename: Raul
authors.initials: R
authors.lastname: Andino
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D005347:Fibroblasts; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D020868:Gene Silencing / Q000187:drug effects; D016679:Genome, Viral; D006367:HeLa Cells; D006801:Humans; D007372:Interferons / Q000502:physiology; D051379:Mice; D009154:Mutation / Q000235:genetics; D017955:Poliovirus / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000276:immunology*; D012330:RNA, Double-Stranded / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D034741:RNA, Small Interfering; D022661:RNA, Untranslated / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology; D014779:Virus Replication / Q000187:drug effects
chemical_list: D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; D022661:RNA, Untranslated; D007372:Interferons