title: Double-stranded RNA induces sequence-specific antiviral silencing in addition to nonspecific immunity in a marine shrimp: convergence of RNA interference and innate immunity in the invertebrate antiviral response?
abstract: Double-stranded RNA (dsRNA) is a common by-product of viral infections and a potent inducer of innate antiviral immune responses in vertebrates. In the marine shrimp Litopenaeus vannamei, innate antiviral immunity is also induced by dsRNA in a sequence-independent manner. In this study, the hypothesis that dsRNA can evoke not only innate antiviral immunity but also a sequence-specific antiviral response in shrimp was tested. It was found that viral sequence-specific dsRNA affords potent antiviral immunity in vivo, implying the involvement of RNA interference (RNAi)-like mechanisms in the antiviral response of the shrimp. Consistent with the activation of RNAi by virus-specific dsRNA, endogenous shrimp genes could be silenced in a systemic fashion by the administration of cognate long dsRNA. While innate antiviral immunity, sequence-dependent antiviral protection, and gene silencing could all be induced by injection of long dsRNA molecules, injection of short interfering RNAs failed to induce similar responses, suggesting a size requirement for extracellular dsRNA to engage antiviral mechanisms and gene silencing. We propose a model of antiviral immunity in shrimp by which viral dsRNA engages not only innate immune pathways but also an RNAi-like mechanism to induce potent antiviral responses in vivo.
authors.affiliation: Marine Biomedicine and Environmental Sciences Center, Medical University of South Carolina, 221 Ft. Johnson Road, Charleston, South Carolina 29412, USA.
authors.forename: Javier
authors.initials: J
authors.lastname: Robalino
authors.forename: Thomas
authors.initials: T
authors.lastname: Bartlett
authors.forename: Eleanor
authors.initials: E
authors.lastname: Shepard
authors.forename: Sarah
authors.initials: S
authors.lastname: Prior
authors.forename: Guillermo
authors.initials: G
authors.lastname: Jaramillo
authors.forename: Edward
authors.initials: E
authors.lastname: Scura
authors.forename: Robert W
authors.initials: RW
authors.lastname: Chapman
authors.forename: Paul S
authors.initials: PS
authors.lastname: Gross
authors.forename: Craig L
authors.initials: CL
authors.lastname: Browdy
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Warr
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D007113:Immunity, Innate; D007273:Injections, Intramuscular; D033561:Penaeidae / Q000235:genetics* / Q000276:immunology* / Q000821:virology; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000008:administration & dosage*; D014779:Virus Replication; D046848:White spot syndrome virus 1 / Q000187:drug effects / Q000235:genetics / Q000276:immunology* / Q000502:physiology
chemical_list: D012330:RNA, Double-Stranded