TRANCE- and CD40 ligand-matured dendritic cells reveal MHC class I-restricted T cells specific for autologous tumor in late-stage ovarian cancer patients.

PURPOSE: The use of mature dendritic cells (DCs) presenting tumor-associated antigens (TAAs) to trigger tumor-specific T cells in vivo or in vitro represents a promising approach for cancer immunotherapy. We hypothesized that tumor antigens, mostly unidentified, are present on ovarian tumor cells and that mature DCs could be used to generate tumor-specific responses in unprimed patients. We also sought to measure preexisting antitumor immunity in patients with advanced ovarian cancer. EXPERIMENTAL DESIGN: Autologous DCs from 10 patients with ovarian cancer were pulsed with killed autologous primary tumors as a source of TAAs. DCs were then cultured in the presence of tumor necrosis factor alpha + TRANCE (tumor necrosis factor-related activation-induced cytokine) to induce maturation. Mature TAA-pulsed DCs were used in vitro to stimulate tumor-specific peripheral blood T cells. RESULTS: TRANCE and CD40 ligand were effective at maturing DCs. T-cell lines were generated in vitro that were capable of secreting IFN-gamma in response to autologous tumor. These tumor-specific T cells were MHC class I restricted. The frequency of tumor-specific T cells in uncultured cells from malignant ascites fluid and peripheral blood was measured in the same patients. CONCLUSIONS: IFN-gamma-secreting tumor-specific T cells were demonstrated at baseline in uncultured T cells from some unvaccinated ovarian cancer patients; however, the T cells could not kill autologous tumor. These data demonstrate that mature DCs presenting tumor antigens from engulfed autologous tumors can be used to augment antitumor immunity in vitro in patients with epithelial ovarian cancer. The results support the feasibility of therapeutic vaccination of ovarian cancer patients.

Tumor-associated macrophages as a source of functional dendritic cells in ovarian cancer patients.

We have generated dendritic cells (DCs) from tumor-associated macrophages (TAMs) obtained from ascites fluid or tumor specimens of ovarian cancer patients, and compared them phenotypically and functionally to DCs derived from the patients' peripheral blood mononuclear cells (PBMCs). Both immature and mature DCs could be generated from TAMs. However, TAM-derived DCs underwent maturation to a lesser degree than PBMC-derived DCs, as measured by DC receptor surface expression. Nonetheless, in allogeneic mixed lymphocyte reactions, TAM-derived DCs stimulated T cell proliferation as efficiently as PBMC-derived DCs. In addition, TAM-derived DCs presenting tumor Ags were capable of stimulating IFN-gamma secretion by tumor-specific T cell lines. Thus, TAMs isolated from ovarian cancer patients can be used to generate significant numbers of DCs. Therefore, TAMs have potential use for either ex vivo or in vivo DC-based immunotherapy, particularly in individuals in which more conventional sources of DCs have been depleted.