title: Absence of PKR attenuates the anti-HSV-1 activity of an adenoviral vector expressing murine IFN-beta.
abstract: A study was undertaken to evaluate the efficacy of an adenoviral vector containing the murine interferon-beta (IFN-beta) transgene (Ad:IFN-beta) against herpes simplex virus type 1 (HSV-1) infection in two transduced cell lines. The transduction of the adenoviral vector efficiency, ranging from 2% to 100%, was dependent on the multiplicity of infection (moi) (0.4-50 plaque-forming units [pfu]/cell). Supernatants from cells transduced with the Ad:IFN-beta but not the adenoviral null vector (Ad:Null) contained biologically active IFN-beta (6.6-106 U/ml depending on the moi). Cells transduced with the Ad:IFN-beta displayed up to 25-fold reduction in viral titers compared with cells transduced with the Ad:Null or nontransduced cell controls. The suppression in viral titer correlated with a reduction in viral gene (alpha, beta, and gamma) and protein expression. The expression of IFN beta-responsive genes, including protein kinase R (PKR) and 2',5'-oligoadenylate synthetase (OAS), were significantly elevated in the Ad:IFN-beta-transduced cells by 12-fold and 25-fold, respectively. However, after infection with HSV-1, a transient but significant drop in PKR but not OAS gene expression was observed 10 h postinfection. The absence of PKR but not RNase L significantly attenuated the antiviral efficacy of the transgene. Collectively, these results illustrate the feasibility of employing a viral vector to deliver a potent antiviral gene to targeted cells without any obvious detriment to the vector itself and support an important role for PKR as a mediator of the anti-HSV-1 activity of type I IFN.
authors.affiliation: Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
authors.forename: Khaldun
authors.initials: K
authors.lastname: Al-Khatib
authors.forename: Bryan R G
authors.initials: BR
authors.lastname: Williams
authors.forename: Robert H
authors.initials: RH
authors.lastname: Silverman
authors.forename: William P
authors.initials: WP
authors.lastname: Halford
authors.forename: Daniel J J
authors.initials: DJ
authors.lastname: Carr
mesh_terms: D015088:2',5'-Oligoadenylate Synthetase / Q000096:biosynthesis / Q000235:genetics; D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D002460:Cell Line / Q000821:virology; D002522:Chlorocebus aethiops; D004722:Endoribonucleases / Q000172:deficiency / Q000502:physiology; D004790:Enzyme Induction; D005240:Feasibility Studies; D005347:Fibroblasts / Q000821:virology*; D015967:Gene Expression Regulation, Viral; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics / Q000494:pharmacology*; D016899:Interferon-beta / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D007739:L Cells / Q000821:virology*; D051379:Mice; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000502:physiology; D018139:Simplexvirus / Q000502:physiology*; D014161:Transduction, Genetic; D014709:Vero Cells; D014764:Viral Proteins / Q000096:biosynthesis / Q000235:genetics; D019892:eIF-2 Kinase / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*
chemical_list: D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D016899:Interferon-beta; D019892:eIF-2 Kinase; D015088:2',5'-Oligoadenylate Synthetase; D004722:Endoribonucleases; C031956:2-5A-dependent ribonuclease