OBJECTIVETo study the maturation effect of CpG2006 and phosphodiester oligonucleotides on leukemia-derived dendritic cells.

METHODSLeukemia cells K562/A02 were induced into dendritic cells by rhGM-CSF and rhIL-4. After 7 days induction, the cell-morphology was observed, the immunophenotype of cells was detected by flow cytometry and the cell function was evaluated by allogeneic mixed lymphocyte reactions, CTL responses and secretion of IL-12 and IL-6. Then a CpG oligonucleotide CpG2006, two synthetic bacterial phosphodiester oligonucleotides A-ODN and T-ODN were added to these leukemia-derived DCs. Three days later, the DCs were re-detected by the above-mentioned methods.

RESULTSAfter induced by CpG2006, A-ODN or T-ODN, the leukemia-derived DCs with typical dendritic morphology were increased. The expressions of CD83, HLA-DR and CD86 were (65.5 +/- 8.4)%, (32.0 +/- 4.3)% and (18.6 +/- 3.2)% respectively in day 7 leukemia-derived DCs, raised to (88.9 +/- 3.6)%, (53.9 +/- 3.2)% and (39.9 +/- 7.3)% respectively after exposing CpG2006 for 3 days; increased to (97.0 +/- 5.3)%, (63.9 +/- 7.3)% and (40.2 +/- 7.4)% respectively after treated by A-ODN; and further increased to (93.26 +/- 4.65)%, (58.3 +/- 5.6)% and (36.2 +/- 6.8)% respectively after treated by T-ODN. These results was markedly different than unaffected cells did. These DCs induced by the above-mentioned three oligonucleotides could upregulate significantly the capacity for stimulating allogeneic T cells. They could also induce CTL to generate specific cytotoxic activity against K562/A02 cells. The secretion of IL-6 and IL-12 was increased remarkably.

CONCLUSIONCpG2006, as well as two phosphodiester oligonucleotides can induce leukemia-derived DCs maturation.