Vaccination of Dendritic Cells Loaded with Interleukin-12-Secreting Cancer Cells Augments In vivo Antitumor Immunity: Characteristics of Syngeneic and Allogeneic Antigen-Presenting Cell Cancer Hybrid Cells
Cancer immunotherapy by fusion of antigen-presenting cells and tumor cells has been shown to induce potent antitumor immunity. In this study, we characterized syngeneic and allogeneic, murine macrophage/dendritic cell (DC)-cancer fusion cells for the antitumor effects. The results showed the superiority of allogeneic cells as fusion partners in both types of antigen-presenting cells in an in vivo immunotherapy model. A potent induction of tumor-specific CTLs was observed in these immunized conditions. In addition, the immunization with DC-cancer fusion cells was better than that with macrophage-cancer fusion cells. Both syngeneic and allogeneic DC-cancer fusion cells induced higher levels of IFN-gamma production than macrophage-cancer fusion cells. Interestingly, allogeneic DC-cancer fusion cells were superior in that they efficiently induced Th1-type cytokines but not the Th2-type cytokines interleukin (IL)-10 and IL-4, whereas syngeneic DC-cancer fusion cells were powerful inducers of both Th1 and Th2 cytokines. These results suggest that allogeneic DCs are suitable as fusion cells in cancer immunotherapy. To further enhance the antitumor immunity in the clinical setting, we prepared DCs fused with IL-12 gene-transferred cancer cells and thus generated IL-12-secreting DC-cancer fusion cells. Immunization with these gene-modified DC-cancer fusion cells was able to elicit a markedly enhanced antitumor effect in the in vivo therapeutic model. This novel IL-12-producing fusion cell vaccine might be one promising intervention for future cancer immunotherapy.
"We speculate that the same effect could not be observed from cells harvested from macrophage-immunized mice due to the intrinsic properties of these APCs in our experimental model. In fact, the low effectiveness of macrophages when compared with DCs in an APC-based immunization model has already been reported (19). Another explanation is based on nonspecific T-cell activation due to bystander effects provided by APCs stimulated via cytokine networks. "
[Show abstract][Hide abstract] ABSTRACT: In the last several years, the use of dendritic cells has been studied as a therapeutic strategy against tumors. Dendritic cells can be pulsed with peptides or full-length protein, or they can be transfected with DNA or RNA. However, comparative studies suggest that transfecting dendritic cells with messenger RNA (mRNA) is superior to other antigen-loading techniques in generating immunocompetent dendritic cells. In the present study, we evaluated a new therapeutic strategy to fight tuberculosis using dendritic cells and macrophages transfected with Hsp65 mRNA. First, we demonstrated that antigen-presenting cells transfected with Hsp65 mRNA exhibit a higher level of expression of co-stimulatory molecules, suggesting that Hsp65 mRNA has immunostimulatory properties. We also demonstrated that spleen cells obtained from animals immunized with mock and Hsp65 mRNA-transfected dendritic cells were able to generate a mixed Th1/Th2 response with production not only of IFN-γ but also of IL-5 and IL-10. In contrast, cells recovered from mice immunized with Hsp65 mRNA-transfected macrophages were able to produce only IL-5. When mice were infected with Mycobacterium tuberculosis and treated with antigen-presenting cells transfected with Hsp65 mRNA (therapeutic immunization), we did not detect any decrease in the lung bacterial load or any preservation of the lung parenchyma, indicating the inability of transfected cells to confer curative effects against tuberculosis. In spite of the lack of therapeutic efficacy, this study reports for the first time the use of antigen-presenting cells transfected with mRNA in experimental tuberculosis.
Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas / Sociedade Brasileira de Biofisica ... [et al.] 09/2012; 45(12). DOI:10.1590/S0100-879X2012007500148 · 1.01 Impact Factor
"Thanks to these features, immunostimulatory DC have drawn attention as a useful component for cancer vaccines  . DC fused with tumor cells (TCs), more than DC variably loaded with antigenic peptides or apoptotic cells, effectively elicited anti-tumor immunity, both in animal models and in cancer patients     . DC–TC hybrids should provide costimulatory proteins and cytokines, in addition to a complete array of tumor antigens presented in the context of class I and II MHC molecules. "
[Show abstract][Hide abstract] ABSTRACT: Main obstacles to cancer vaccine efficacy are pre-existing antigenic load and immunoescape mechanisms, including tolerance against self tumor-associated antigens. Here we explored the role of tolerance in an antimetastatic vaccine approach based on dendritic cell-tumor cell (DC-TC) hybrids, thanks to the comparison between BALB-neuT mice, transgenic for and tolerant to rat HER-2/neu, with their non-tolerant strain of origin BALB/c. Allogeneic DC-TC hybrid vaccine displayed a high antimetastatic activity in non-tolerant mice, but was far less effective in tolerant mice, even with intensified vaccine schedule. Tolerant BALB-neuT mice revealed a reduced ability to mount polarized Th1 responses. A further attempt to increase the antimetastatic activity by using LPS-matured DC hybrids failed. Allogeneic LPS-matured DC-TC hybrids induced high IFN-γ levels, but concomitantly also the highest production of IL-4 and IL-10 suggesting activation of mechanisms sustaining regulatory cells able to blunt vaccine efficacy. Our data in tolerant versus non-tolerant hosts suggest that clinical translation of effective DC-based strategies could benefit from more extensive investigations in tolerant transgenic models.
"There is a currently great interest in the assay of polyfunctional T cells, secreting multiple cytokines (e.g., secreting IFN-γ and TNF-α rather than either alone), or expressing multiple surface markers. As the release of Th1 cytokines such as IFN-γ and TNF-α is important to determine long-lasting antitumor immunity, a shift to Th1 response by cancer vaccines is essential for therapeutic potential in murine models [36, 37, 67, 77, 137, 138]. Therefore, it is important to test whether cancer vaccines can induce a Th1 response in the tumor-specific T cells, and what impact might this have on the clinical responses. "
[Show abstract][Hide abstract] ABSTRACT: Although dendritic cell (DC)- based cancer vaccines induce effective antitumor activities in murine models, only limited therapeutic results have been obtained in clinical trials. As cancer vaccines induce antitumor activities by eliciting or modifying immune responses in patients with cancer, the Response Evaluation Criteria in Solid Tumors (RECIST) and WHO criteria, designed to detect early effects of cytotoxic chemotherapy in solid tumors, may not provide a complete assessment of cancer vaccines. The problem may, in part, be resolved by carrying out immunologic cellular monitoring, which is one prerequisite for rational development of cancer vaccines. In this review, we will discuss immunologic monitoring of cellular responses for the evaluation of cancer vaccines including fusions of DC and whole tumor cell.
BioMed Research International 04/2011; 2011(1110-7243):910836. DOI:10.1155/2011/910836 · 2.71 Impact Factor
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