Retroviral interleukin-7 gene transfer into human dendritic cells enhances T cell activation.
Tumor vaccination with dendritic cells (DC) presenting tumor antigens to T cells is a promising approach in immunotherapy. The aim of this study was to enhance T cell stimulatory ability of human DC by retroviral expression of the interleukin-7 (IL-7) gene. IL-7 has been shown to provide a potent costimulatory signal for the proliferation of T cells and the generation of cytotoxic T cells (CTL). DC were generated from human peripheral blood mononuclear cells (PBMC). DC were analyzed by light- and electron-microscopy, immunophenotype (CD1a+, CD14-, CD80+, CD86+, HLA-DR+) and functional assays. According to these criteria, 75-85% of the cells were DC. The cells did not produce measurable amounts of IL-7 spontaneously nor did they express the IL-7 receptor. A retroviral IL-7 expression vector was constructed. Retroviral infection was performed with either the LXSN-hIL-7 vector of its variant LXSN. Using the LXSN-hIL-7 vector, IL-7 production of 2296 pg/10(6) cells/24 h could be achieved on average. Transduction of DC was confirmed by RT-PCR in a CD1a-enriched cell fraction. Transduction efficiency by a control virus coding for beta-galactosidase was about 30%. In autologous mixed lymphocyte reaction (MLR), IL-7 transduced DC augmented T cell proliferation by a factor of two compared with unmodified or mock-transfected DC, and in allogeneic MLR there was a 2.7-fold increase in T cell proliferation. The increase in T cell proliferation could be correlated to IL-7 secretion by DC. Dendritic cells that have been simultaneously peptide-loaded and gene-modified to secrete IL-7 are a potential tool to amplify activation of tumor-specific T cells.
Westermann
J
J
Department of Hematology/Oncology and Tumorimmunology, Robert-Rössle Klinik, Virchow-Klinikum, Humboldt University, Berlin, Germany.
Aicher
A
A
Qin
Z
Z
Cayeux
Z
Z
Daemen
K
K
Blankenstein
T
T
Dörken
B
B
Pezzutto
A
A
D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology* / Q000648:ultrastructure; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006801:Humans; D015851:Interleukin-7 / Q000032:analysis / Q000235:genetics*; D008213:Lymphocyte Activation; D008854:Microscopy, Electron; D008858:Microscopy, Phase-Contrast; D016133:Polymerase Chain Reaction; D012190:Retroviridae; D013601:T-Lymphocytes / Q000502:physiology*
D015851:Interleukin-7