Effect Of Polyriboinosinic Polyribocytidylic Acid (PolyI:C) On Function Of Dendritic Cells Induced From Human Umbilical Cord Blood

OBJECTIVE:To observe the effect of polyriboinosinic polyribocytidylic acid (polyI:C, P) on the maturation of dendritic cells (DC) derived from human umbilical cord blood in vitro and to investigate the effect of polyI:C on the anti-leukemia immune effect induced by dendritic cells derived from human umbilical cord blood. METHODS:MNC isolated by density gradient centrifugation from human umbilical cord blood and cultured with RPMI-1640 in the control group, while the test group were cultured with P+RPMI-1640, rhGM-CSF+rhIL-4+rhTNF-α+RPMI-1640(GIT), GIT+P+ RPMI-1640(GITP) respectively. Cultured cells were analyzed by microscope and numbers of live cells were calculated by trypan blue. We determined the phenotypes of DC by flow cytometry and dyed some harvest cells with WrightGiemsa , then observed and photoed them under an oil microscope. The mononuclear cells were isolated and cultured with rhGM-CSF+rhIL-4+rhTNF-α+RPMI-1640 in the control and test group. Moreover, we put HL-60 complete cell antigen into the control group on the 4th and 9th day of culture. Besides, on the 7th day, we put different quantity of polyI:C into every test groups and kept its effect for different time respectively. The phenotypes of DC were determined by flow cytometry on the 12th day of culture, then mixed DC with T lymphocytes derived from patients who suffered with acute myeloblastic leukemia to induce antigen specific cytotoxic T cells. Cytotoxicity assay was measured by MTT method.RESULTS:①There was a certain amount of typical DC in all test groups; Both CD1a positive cell rate and CD83 positive cell rate of the P group were higher than those of the control; CD83 positive cell rate of the GIP group increased most significantly, much higher than that of the GIT group.②The concentration and action time of polyI:C both had no effect on CD1a positive cell rate. But the concentration and action time of polyI:C had an effect on CD83 positive cell rate and the cytotoxicity, CD83 positive cell rate and the cytotoxicity of the test groups were higher than that of those in the control group. Within a certain scope, along with the increase of polyI:C concentration and action time, CD83 positive cell rate and the cytotoxicity increased accordingly.CONCLUSION:①Polyriboinosinic polyribocytidylic acid (polyI:C) not only promotes the maturity of DC derived from human umbilical cord blood in vitro, but also co-operates wih rhGM-CSF,rhIL-4 and rhTNF-αin promoting the proliferation of DC.②polyI:C may quickly promote the maturity of DC and boost the ability of DC in antigen presentation, thus, it can enhance the anti-leukemia immune effect induced by dendritics cells derived from human umbilical cord blood.