RESUMO
Dendritic cells (DC) are important antigen-presenting cells in the development of anti-leukemic T-cells responses and it' s reported that DC can differentiate from monocytes or granulocytes in vitro. In the present study, the human leukemic DC were generated from acute promyelocytic leukemic( APL)cells after treatment with cytokines. M3 APL cells were isolated from peripheral blood of patients and incubated with rhGM-CSF( 100ng/ml)or rhGM-CSF( lOOng/ml) plus rhIL-4(500U/ml)for 14 days and the cells were co-cultured wirh TNF-?(100ng/ml)during last 3 days. The results demonstrated that both proliferation and differentiation of APL cells were induced by GM-CSF as the number of cultured cells increased and the cells expressed high level of CD45. Some cells displayed the characteristics of monocytes which expressed CD14 and some were leukemic DC as they expressed GDI a. The co-culturation of APL cells with GM-CSF and TNF-? augmented the differentiation of cells and about 35 percent of leukemic DC generated (was obtained). The maturation of APL cells could also be induced by GM-CSF plus IL-4 but there were few monocytes generated and about 10 percent of the cells were leukemic DC. If cultured for 3 weeks, the number of leukemic DC increased to 60 percent. The addition of TNF-? could augmented GM-CSF and IL-4 induced maturation of cells significantly and 90 percent of leukemic DC generated. Analysis of the cells with electric microscopy indicated that these leukemic DC displayed the similarly morphologic characteristics as monocyte-derived DC and there were still a few granules in their cytoplasm. The leukemic DC expressed high levels of HLA-DR, B7-1, B7-2 and CD54 molecules and could stimulate allo-T cells to proliferate in vitro. Such kind of leukemic DC might be useful tools for the generation of specific anti-tumor CTL and play important roles in immunotherapy of APL.