Search

Abstract: Fetal calf serum (FCS)-independent pancreatic cancer cells were established in plasma protein fraction (PPF)-supplemented medium that is an agent of good manufacturing practice (GMP) grade. Dendritic cells (DCs) were activated with the Toll-like receptor agonist, penicillin-inactivated Streptococcus pyogenes (OK-432) that is also a GMP grade agent. Therefore, sufficient amounts of FCS-independent fusions were successfully generated with decreased potential hazards of FCS. The FCS-independent fusions expressed tumor-associated antigens, HLA-DR, costimulatory molecules, IL-12, and IL-10. Stimulation of T cells with fusions from healthy donors resulted in proliferation of T cells with high expression levels of perforin/granzyme B and IFN-γ and efficient induction of antigen-specific cytotoxic T lymphocytes (CTLs). Selection and expansion of T-cell clones were confirmed by TCR Vβ analysis. However, fusions from patients with metastatic pancreatic cancer induced increased expression levels of TGF-β1 in CD4+ CD25high T cells and low levels of CTLs with decreased IFN-γ production. [Copyright &y& Elsevier]

Fusion of human dendritic cells (DC) with tumor cells is an effective approach for delivering tumor antigens to DC, and DC/tumor fusion cells are potent stimulators of autologous T cells. However, the integration and morphology of DC/tumor fusion cells has not been examined. In the present study, we fused patient-derived DC to autologous breast or ovarian carcinoma cells. The fusion cells possessed the properties of both parent cells. After fusion, the cytoplasm of the two cells was integrated, whereas their nuclei remained separate entities. Colocalization of MUC1 peptide and HLA-DR molecules was observed on fusion cells under the immunoelectron microscope. Coculture of patient-derived peripheral blood mononuclear cells (PBMC) with DC/tumor fusion cells resulted in activation of CD4 and CD8 T cells as assessed by IFN-γ secretion, HLA-A*0201-MUC1 tetramer, and standard cytotoxic T lymphocyte (CTL) assays. The present study provides first evidence of integration of human DC and tumor cells and links their properties to T cell activation. [Copyright &y& Elsevier]