Low antigen-dependent activity of T cells after repeated stimulation using dendritic cells and expansion with interleukin-2.
|Year of publication||2003|
|Type||Article in Periodical|
|Magazine / Source||Neoplasma|
|MU Faculty or unit|
|Field||Oncology and hematology|
|Keywords||dendritic cell; IL-2;T cell|
|Description||Both CD8+ and CD4+ T cells with specific activity against tumor antigens are needed for an efficient antitumor immune response. Activation and proliferation of T cells require cellular interactions including adhesion, recognition of peptides presented by MHC molecules to the T cells receptor, and costimulation. In a series of experiments we attempted to generate and expand specific T cells by repeated stimulation using antigen-loaded autologous dendritic cells (DCs). DCs were obtained from peripheral blood mononuclear cells (PBMC) in the presence of IL-4 and GM-CSF. TNF-alpha was added to induce maturation. A conjugate of myeloma idiotypic protein with keyhole limpet hemocyanin was used as antigen. Nonadherent peripheral blood mononuclear cells were cultured in the presence of II-2 and IL-7. Autologous DCs were added to the lymphocyte cultures on days 3, 10, and 17. The lymphocytes were stimulated by high concentration of IL-2 between days 21 and 27. Lymphocytes harvested on day 27 proliferated in response to antigen-loaded DC but failed to do so if less than 0.3x10(6) DCs were added for stimulation during culture. However, no cytotoxic activity against autologous DCs was detected and IFN-gamma production in the T cell cultures was low at the end of culture. In conclusion, the generation and expansion of T cells using repeated stimulation by autologous DCs is feasible but defective cytotoxic reponse of these cells occurs, possibly as a consequence of repeated frequent exposure to antigen.|