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Dendritic cells (DCs) primed with tumor antigens (Ags) can stimulate tumor rejection. This study was aimed at evaluating the polarization of T-cell responses using various DC Ag-priming strategies for vaccination purposes. DCs cocultured with irradiated "apoptotic" tumor cells, DC-tumor fusions, and DCs pulsed with freeze-thaw tumor lysate Ags served as Ag-primed DCs, with EG7 tumor cells (class II negative) expressing OVA as the model Ag. DCs loaded with class I- and class II-restricted OVA synthetic peptides served as controls. Primed DCs were assessed by the in vitro activation of B3Z OVA-specific CD8 T cells and the proliferation of OVA-specific CD8 and CD4 T cells from OT-I and OT-II TCR transgenic mice, respectively. In vivo responses were measured by tumor regression following treatment with Ag-primed DCs and by CTL assays. Quantification of IL-2, IL-4, IL-5, IFN-gamma, and TNF-alpha by cytometric bead array (CBA) assay determined the polarization of TH1/TH2 responses, whereas H-2 Kb/SIINFEKL tetramers monitored the expansion of OVA-specific T cells. DC-EG7 hybrids stimulated both efficient class I and class II OVA responses, showing that DC-tumor hybrids are also capable of class II cross-presentation. The hybrids also induced the most potent CTLs, offered the highest protection against established EG7 tumors and also induced the highest stimulation of IFN-gamma and TNF-alpha production. DCs cocultured with irradiated EG7 were also effective at inducing OVA-specific responses, however with slightly reduced potency to those evoked by the hybrids. DCs loaded with lysates Ags were much less efficient at stimulating any of the OVA-specific T-cell responses, showed very little antitumor protection, and stimulated a weak TH1 response, overbalanced by an IL-5 TH2 response. The strategy of Ag-loading clearly influences the ability of DCs to polarize T cells for a TH1/TH2 response and thus determines the outcome of the elicited immune response, during various vaccination protocols.

Original publication

DOI

10.1007/s00262-004-0542-8

Type

Journal article

Journal

Cancer immunol immunother

Publication Date

11/2004

Volume

53

Pages

963 - 977

Keywords

Animals, Antigens, Antigens, Neoplasm, Apoptosis, CD8 Antigens, CD8-Positive T-Lymphocytes, Cancer Vaccines, Cell Division, Cell Line, Tumor, Cell Separation, Cytokines, Dendritic Cells, Flow Cytometry, Interferon-gamma, Interleukin-2, Interleukin-4, Interleukin-5, Lymphocytes, Mice, Mice, Inbred C57BL, Ovalbumin, Peptides, Recombinant Fusion Proteins, T-Lymphocytes, Th1 Cells, Tumor Necrosis Factor-alpha