title: Ex vivo generation of genetically modified dendritic cells for immunotherapy: implications of lymphocyte contamination.
abstract: Genetically modified dendritic cell (DC) vaccines expressing tumor-associated antigens are currently used for cancer immunotherapy. Peripheral blood (PB) monocyte precursors are a relatively convenient source of DCs for use in clinical studies, but are often contaminated by lymphocytes. The current study was conducted to examine the impact of T-lymphocyte contamination on genetically modified DC product. PB monocyte-derived DCs were efficiently transduced (75-95%) with an HIV-1-based self-inactivating lentiviral vector encoding a model antigen, the enhanced green fluorescent protein (eGFP). The lymphocyte-free DC culture transduced with Lenti-eGFP showed stable expression of eGFP without measurable decline in viability. In contrast, the eGFP-positive DCs disappeared rapidly in transduced DC cultures containing lymphocyte contaminants, concurrent with detectable activation and expansion of T-lymphocytes. Upon antigen recall, these T cells elicited major histocompatability complex-restricted antigen-specific cytotoxicity against eGFP-positive autologous DCs and mitogen-stimulated T lymphoblasts, mainly through the perforin-mediated pathway. In summary, this study demonstrate that the relative purity of DC cultures could determine the persistence of gene-modified DC, which may affect the induction of effective immune responses by DC vaccination strategies.
authors.affiliation: Immunotherapy Program, Vince Lombardi Gene Therapy Laboratory, Aurora Health Care, St Luke's Medical Center, Milwaukee, WI 53215, USA.
authors.forename: N
authors.initials: N
authors.lastname: Chinnasamy
authors.forename: J S
authors.initials: JS
authors.lastname: Treisman
authors.forename: M K
authors.initials: MK
authors.lastname: Oaks
authors.forename: J P
authors.initials: JP
authors.lastname: Hanson
authors.forename: D
authors.initials: D
authors.lastname: Chinnasamy
mesh_terms: D019264:Adoptive Transfer; D019496:Cancer Vaccines; D003713:Dendritic Cells; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics; D015497:HIV-1 / Q000235:genetics; D006801:Humans; D008214:Lymphocytes; D009369:Neoplasms / Q000628:therapy*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D014161:Transduction, Genetic / Q000379:methods
chemical_list: D019496:Cancer Vaccines; D049452:Green Fluorescent Proteins