title: Gene transfer of a chimeric trans-activator is immunogenic and results in short-lived transgene expression.
abstract: Pharmacologic gene regulation is a key technology, necessary to achieve safe, long-term gene transfer. The approaches described in the scientific literature all share in common the creation of artificial transcription factors by fusing a DNA-binding domain, a drug-binding domain and a transcription activation domain. These transcription factors activate the transgene expression upon binding of the pharmacologic agent (antibiotics of the tetracycline family, insect hormone, progesterone antagonist, or immunosuppressor drug) to the drug-binding domain. The major limitations to the use of these systems for human gene and cell therapies are the toxicity of the inducer molecule and the immunogenicity of the chimeric transcription factor. Thus, the gene regulation systems should operate with clinically approved drugs with safety records that do not conflict with the therapeutic gene expression regimen. This work focuses on the characterization of the immunogenicity of a tetracycline-activated transcription factor commonly used in preclinical gene therapy, rtTA2-M2, and its impact on reporter gene expression. We demonstrate that intramuscular injection of plasmid or adenoviral vectors encoding rtTA-M2 in outbred primates generates a cellular and humoral immune response to this transcription factor. The immune response to rtTA2-M2 blunts the duration of the expression the rtTA2-M2-controlled transgene in primates, presumably by destruction of the cells that coexpress rtTA2-M2 and the reporter or therapeutic gene. This immune response may result directly from the vectors used in this study, which prompts the development of new gene transfer vectors enabling safe and efficient pharmacologic gene regulation in clinic.
authors.affiliation: Gencell, Bat. Monod, 94403 Vitry sur Seine, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Latta-Mahieu
authors.forename: Magali
authors.initials: M
authors.lastname: Rolland
authors.forename: Catherine
authors.initials: C
authors.lastname: Caillet
authors.forename: Manping
authors.initials: M
authors.lastname: Wang
authors.forename: Philippe
authors.initials: P
authors.lastname: Kennel
authors.forename: Irene
authors.initials: I
authors.lastname: Mahfouz
authors.forename: Isabelle
authors.initials: I
authors.lastname: Loquet
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Dedieu
authors.forename: Abderrahim
authors.initials: A
authors.lastname: Mahfoudi
authors.forename: Emanuelle
authors.initials: E
authors.lastname: Trannoy
authors.forename: Vincent
authors.initials: V
authors.lastname: Thuillier
mesh_terms: D000818:Animals; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism; D008252:Macaca fascicularis; D011993:Recombinant Fusion Proteins / Q000235:genetics* / Q000276:immunology; D015534:Trans-Activators / Q000276:immunology; D019076:Transgenes
chemical_list: D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D007371:Interferon-gamma