| Background and Objective:The major cause of treatment failure in acute myeloid leukemia (AML) is minimal residual disease. Minimal residual disease is key to treatment. Dendritic cells (DCs) are the most potent APCs in the immune system and the only ones capable of sensitising naive, unprimed T cells. Thus, DCs are central to the initiation of primary, specific immune responses and are therefore important for the induction of anticancer immunity. Most frequently used in common studies were the cytokine combinations granulocyte-macrophage colony-stimulating factor(GM-CSF) and interleukin(Il)-4.In this condition,cells culture need a long time and a lot of cytokines.There was a possibility of contamination.An alternative and practically simple method for the in vitro generation of DC-like cells was proposee recently by one group.They demonstrated that immature CD34+haemopoirtic progenitor cells,as well as normal peripheral blood monocytes and certain myelogenous leukaemia cells lines,can be induced to acquire the typical characteristica of DC simply by culturing them in the presence of calcium ionophore.We investigate the question of whether primary AML cells can be driven along the DC differetiation pathway with CI as the only stimulus and how the effects of CI compare with the effects of cytokine stimulation. .There are recent data suggesting that DCs can also be derived from more committed myeloid precursorsand that reversal of the granulocyte maturation pathway can also yield candidate DCs. Myeloid malignancies therefore provide a unique opportunity to derive APCs from the malignant cells themselves, which may then combine expression of leukemic antigens with the presence of the necessary costimulatory signals and be used to generate a specific antileukemic immune response. Methods: bone marrow (BM) samples were from 8 patients with AML at presentation or relapse.Mononuclear cells were islated from heparinized whole blood of AML patients using standard density gradient centrifugation with Ficoll-Paque.MNCwere cultured in 24-well plates. A23187(CI) or a cocktail consisting of GM-CSF and IL-4(CK) was added. After 4 days of cultivation,cells were harvested ,washed and subsequently analysed.The morphology of cells were detected by using invert microscope .Method of flow cytometry was used to determine cell surface antigens before and after culture by using monoclonal antibodids.The monoclonal antibodies included CD83,CDW123,CD14,HLA-DR. The proliferation of T cells was performed by methyul thiazolyl tetrazolium(MTT) assay.The specific antileukemic cytotoxicity of T cells primed with leukemic DC was examined by MTT assay. Results:1.After 4 days, cells cultured either in CI or in CK were shifed along the DC pathway: typical cytoplasmic motile processes,association in clusters, irregular cellular surface, varible size increases,relatived to the cytoplasmic proportion,small condensed nuclei.The percentage of DC after CI-treated was in the range of 30%-60%,while the percetage of DC after CK-treated was less than 30%.2.Through flow cytometry,we found that treatment of AML cells with CI lead to higher express levels of CD83,CDW123,HLA-DR.CD14 was down-regulated.Although the silimar change was observed in the AML cells cultured with CK, up-regulated of CD83 was never detected.3.CI-treated stimulator cells induced an enhanced proliferativeallogeneic T-cell response compared with cytokine-treated stimulator cells.(P<0.05).4.At effector/target ratio of 50:1, auto-T lymphocytotic primed with the culture-derived DC exhibited more killing activity to auto-AML cells than those stimulated by IL-2 alone. Conclusions: 1.CI could in vitro induce AML cells into DC with classical morphology, immunophenotype and function. 2.CI could induce AML cells into DC rapidly,and the DCs cultured with CI were more mature than those cultured with cytokine. 3. auto-T lymphocytotic primed with the culture-derived DC exhibited more killing activity to auto-AML cells. |
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