Abstract
Vaccination with hybrids comprising fused dendritic cells (DCs) and tumor cells is a novel cancer immunotherapy approach designed to combine tumor antigenicity with the antigen-presenting and immunestimulatory capacities of DCs. For clinical purposes, we have incorporated a large-scale process for the generation of clinical-grade DCs together with novel electrofusion technology. The electrofusion system provides for ease and standardization of method, efficient DC-tumor cell hybrid formation, and large-quantity production of hybrids in a high-volume (6-ml) electrofusion chamber. In addition, we have evaluated DC electrofusion with a variety of allogeneic human tumor cell lines with the rationale that these tumor cell partners would prove a ready, suitable source for the generation of DC-tumor cell hybrid vaccines. The DC production process can generate 6×108 to 2×109 DCs from a single leukapheresis product (∼180 ml). As determined by FACS analysis, electrofusion of 6×107 total cells (1:1 ratio of DC and tumor cells) resulted in a consistent average of 8-10% DC-tumor cell hybrids, irrespective of the tumor type used. Hybrids were retained in the population for 48 h postfusion and following freezing and thawing. Upon pre-irradiation of the tumor cell partner for vaccine purposes, the overall fusion efficiency was not altered at doses up to 200 Gy. Evaluation of DC-tumor cell hybrid populations for their ability to stimulate T-cell responses demonstrated that electrofused populations are superior to mixed populations of DCs and tumor cells in generating a primary T-cell response, as indicated by IFN-γ release. Moreover, hybrids comprising HLA-A*0201 DCs and allogeneic melanoma tumor cells (Colo 829 cell line) stimulated IFN-γ secretion by antigen-specific CD8+ T cells, which are restricted for recognition of a melanoma gp100 peptide antigen (gp100209-217) within the context of the DC HLA haplotype. Maturation of the DC-Colo 829 cell hybrid population served to further improve this T-cell gp100-specific response. Overall, our results are promising for the large-scale generation of electrofused hybrids comprising DCs and allogeneic tumor cells, that may prove useful in human vaccine trials.
Original language | English (US) |
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Pages (from-to) | 705-714 |
Number of pages | 10 |
Journal | Cancer Immunology, Immunotherapy |
Volume | 53 |
Issue number | 8 |
DOIs | |
State | Published - Aug 2004 |
Keywords
- Cancer
- Dendritic cells
- Electrofusion
- Hybrids
- Immunotherapy
ASJC Scopus subject areas
- Immunology and Allergy
- Immunology
- Oncology
- Cancer Research