| Objective To investigate and compare the anti-leukemic effect mediated by dendritic cells(DCs) derived from multidrug resistant (MDR)leukemia HL-60/VCR cells and sensitive HL-60 cells.Methods Multidrug resistant HL-60/VCR cell line with high expression of p- glycoprotein( P-gp) and sensitive HL-60 cell line from acute myeloid leukemia (AML) were induced for differentiating to DC in complete RPMI1640 culture medium supplemented with GM-CSF(100ng /ml),IL-4(100ng/ml) and TNF-α(100ng /ml) for 14 days. The morphologic features of DC were observed by means of invertmicroscope and the phenotype of DC was detected by flow cy-tometry. The cytotoxity of actived T lymphocyte to HL-60/VCR cells and HL-60 cells was measured by MTT assay in vitro.Results It was demonstrated that DCs derived from MRD HL-60/VCR cells and HL-60 cells similarly showed the typical morphology of dendritic cell .The levels of the surface differentiation antigens CD1a, CD83 on DCs were obviously higher than those before culture (P < 0. 01). The induced DCs could similarly generate specific cytotoxic activity against HL-60/VCR cells or HL-60 cells respectively. More importantly, cytotoxicity mediated by HL-60/VCR-DC was stronger than that by HL-60-DC against HL-60/VCR cells ( 47.38±5.00% versus 34.29±1.35% at effectors:targets of 20:1, P < 0. 01) .Conclusions It is concluded that functional DC with enhanced antigen-presenting can be differentiated from multidrug resistant leukemia HL-60/VCR cells as well as sensitive HL-60 cells in the presence of GM-CSF, IL-4 and TNF-α,and these DCs reserved the specific tumor antigens and could mediate effectively specific cytotoxicity T lymphocyte(CTL) immune response. Especially, the CTL induced by HL -60/VCR-DC could strongly mediate cytotoxicity against mufti-drug resistant HL-60/VCR cells than those induced by HL-60-DC. This maybe provides an experimental basis for immunotherapy to overcome mufti-drug resistance tumors.
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