Immunotherapy using dendritic cells (DC) loaded with tumor antigens may represent a potentially effective method for inducing antitumor immunity. We evaluated the effectiveness of DC-based antitumor immune response in various conditions.

DC were cultured from peripheral blood mononuclear cells (PBMNC) in myelogenous leukemia (ML) and lysates of autologous leukemic cells are used as tumor antigen. The effectiveness of interleukin-12 (IL-12) and CD40L (CD154) on the antigen presenting function of lysates-loaded DC was analyzed by proliferation, cytokine production, and cytotoxicity tests with activated PBMNC (mainly lymphocytes). For generating antigen-loaded DC, direct fusion of DC with ML was studied.

Antigen loaded DC induced significantly effective antitumor immune response against autologous leukemic cells. Administration of IL-12 on the DC based antitumor immune response showed higher proliferation activity, IFN-γ production, and cytotoxic activity of PBMNC. Also, fused cell has a potent antitumor immune response.

We conclude that lysates-loaded DC with IL-12 may be effectively utilized as inducer of antitumor immune reaction in ML and in vivo application with DC-based antitumor immunotherapy or tumor vaccination seems to be feasible.