title: Helper-dependent adenoviral vectors efficiently express transgenes in human dendritic cells but still stimulate antiviral immune responses.
abstract: Adenoviral (AdV) vectors can be used to transduce a wide range of human cells and tissues. However, pre-existing immunity to AdV, and enhancement of this immunity after repeated administration, limits their clinical application. This may be especially relevant when vectors are loaded into APCs. Helper-dependent AdV (Hd-AdV), in which viral coding regions are replaced by human stuffer DNA, offers a new approach for limiting antiviral responses. To evaluate their immunogenicity, human dendritic cells (DCs) were infected with either an Hd-AdV or a conventional replication-deficient E1-deleted AdV (E1-AdV) and were evaluated for their capacity to stimulate antiviral T cell responses. Hd-AdV proved to be 50- to 275-fold more effective than E1-AdV at expressing the lacZ transgene in human DCs. PCR demonstrated similar transduction efficiencies, but RT-PCR revealed much higher expression of transgene mRNA after transduction with Hd-AdV. Functionally, DCs transduced with Hd-AdV stimulated the proliferation of autologous T cells to the same level as DCs transduced with E1-AdV. Identical viral-specific T cell responder frequencies were observed and T cells stimulated with either type of AdV-transduced DC lysed viral-infected target cells. Disrupting transcription of vector-based genes had no effect on T cell activation, suggesting that responses against both vectors were directed against preformed components of the viral capsid. We conclude that Hd-AdV vectors can be used to obtain higher transgene expression in human DCs but that they still evoke a vector-related immune response similar to that generated by E1-AdV.
authors.affiliation: Pulmonary and Critical Care Medicine, School of Medicine, University of California-Los Angeles, Los Angeles, CA 90095, USA. mroth@mednet.ucla.edu
authors.forename: Michael D
authors.initials: MD
authors.lastname: Roth
authors.forename: Qingwen
authors.initials: Q
authors.lastname: Cheng
authors.forename: Airi
authors.initials: A
authors.lastname: Harui
authors.forename: Saroj K
authors.initials: SK
authors.lastname: Basak
authors.forename: Kohnosuke
authors.initials: K
authors.lastname: Mitani
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Low
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Kiertscher
mesh_terms: D000260:Adenoviruses, Human / Q000235:genetics* / Q000276:immunology*; D002213:Capsid / Q000276:immunology; D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000235:genetics / Q000276:immunology; D003601:Cytotoxicity Tests, Immunologic; D003713:Dendritic Cells / Q000276:immunology* / Q000821:virology*; D017353:Gene Deletion; D015967:Gene Expression Regulation, Viral / Q000276:immunology*; D017781:Genes, Immediate-Early / Q000276:immunology; D005822:Genetic Vectors / Q000276:immunology; D006378:Helper Viruses / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology / Q000821:virology; D014158:Transcription, Genetic / Q000276:immunology; D014161:Transduction, Genetic; D019076:Transgenes / Q000276:immunology*; D014407:Tumor Cells, Cultured; D019562:Viral Load