Alpha-Type 1 Polarized Dendritic Cells Loaded with Apoptotic Allogeneic Breast Cancer Cells Can Induce Potent Cytotoxic T Lymphocytes against Breast Cancer.

PURPOSE: Various tumor antigens can be loaded onto dendritic cells (DCs) to induce a potent cytotoxic T lymphocyte (CTL) response in DC-based immunotherapy against breast cancer. However, in the clinical setting, obtaining a sufficient number of autologous tumor cells as a source of tumor antigens is a laborious process. We therefore investigated the feasibility of immunotherapy using breast-cancer-specific CTLs generated in vitro by use of alpha-type 1 polarized DCs (α DC1s) loaded with ultraviolet B-irradiated cells of the breast cancer cell line MCF-7. MATERIALS AND METHODS: αDC1s were induced by loading allogeneic tumor antigen generated from the MCF-7 UVB-irradiated breast cancer cell line. Antigen-pulsed αDC1s were evaluated by morphological and functional assays, and the breast-cancer-specific CTL response was analyzed by cytotoxic assay. RESULTS: The αDC1s significantly increased the expression of several molecules related to DC maturation without differences according to whether the αDC1s were loaded with tumor antigens. The αDC1s showed a high production of interleukin-12 both during maturation and after subsequent stimulation with CD40L, which was not significantly affected by loading with tumor antigens. Breast-cancer-specific CTLs against autologous breast cancer cells were successfully induced by αDC1s loaded with apoptotic MCF-7 cells. CONCLUSION: Autologous DCs loaded with an allogeneic breast cancer cell line can generate potent breast-cancer-specific CTL responses. This may be a practical method for cellular immunotherapy in patients with breast cancer.

Optimization of the concentration of autologous serum for generation of leukemic dendritic cells from acute myeloid leukemic cells for clinical immunotherapy.

Clinical application of immunotherapy for acute myeloid leukemia (AML) requires the efficient induction of dendritic cells (DCs) from AML blast cells using in vitro culture. We examined the effect of autologous serum on the properties of leukemic DCs derived from leukemic cells of AML patients by culture in AIM-V medium with GM-CSF, IL-4, TNF-alpha, and 0, 2, 5, or 10% human autologous serum. The expressions of CD80, CD83, CD86, and HLA-DR were upregulated under all culture conditions; however, 10% autologous serum induced the highest expression levels of several molecules. The capacity of leukemic DCs to stimulate allogeneic T cells increased with increasing serum concentration. Stimulation of autologous CD3(+) T cells with leukemic DCs grown in the presence of various concentrations of autologous serum resulted in induction of more IFN-gamma-secreting cells than was the case for unprimed CD3(+) T cells. Leukemic DCs cultured with 10% autologous serum induced the highest numbers of IFN-gamma-secreting cells and CD8(+)CD56(+) T cells from autologous T cells. These results suggest that culture of AML blast cells in the presence of autologous serum could be used to generate leukemic DCs for immunotherapy against AML. The highest serum concentration appeared optimal for generating the most potent leukemic DCs.

Down-regulation of cellular vascular endothelial growth factor levels induces differentiation of leukemic cells to functional leukemic-dendritic cells in acute myeloid leukemia.

We examined the effect of cellular vascular endothelial growth factor (VEGF) levels on the generation of leukemic dendritic cells (DCs). Leukemic DCs were successfully generated in vitro from bone marrow cells of 16 of 21 acute myeloid leukemia (AML) patients, and the cellular VEGF concentrations in the leukemic cells and the neutralization of VEGF with anti-VEGF antibody were determined. AML cells that failed to generate leukemic DCs showed significantly higher cellular VEGF levels compared with generated leukemic DCs, and down-regulation of cellular VEGF levels induced the generation of leukemic DCs from AML cells. Inhibition of cellular VEGF levels increased interleukin (IL)-12 production and the allostimulatory capacity of leukemic DCs. These results suggest that the generation of leukemic DCs from AML cells is inversely related to the VEGF production of the cells and that the down-regulation of cellular VEGF levels can induce potential differentiation of leukemic cells to functional leukemic DCs in patients with AML.