The Effect Of Tα1 On The Antigen Presentation Ability Of Dentritic Cells Derived From Children With Leukemia

Objective To investigate the effect of thymosin alpha-1(Tα1) on the antigen presentation ability mediated by leukemia tumor antigen- loaded Dentritic Cells (DCs) derived from children acute leukemia(AL) peripheral blood in vitro. Method 10 acute lymphoblastic leukemia (ALL) children in complete remission were detected. The peripheral blood mononuclear cells (PBMC) samples of these children were obtained and divided into control group and test group respectively. The control group was cultured with rhGM-CSF+rhIL-4+rhTNF-a (GIT), while the test groups were cultured with rhGM-CSF+rhIL-4+rhTNF-a+HL-60 cells freeze thawing antigens (GITA,rhGM-CSF+rhIL-4+rhTNF-a+HL-60 cells freeze-thawing tumor antigen+ Tα1 (GITAT) respectively. The growth of DCs was observed under a optical microscope. We detected the immunephenotypes of DCs (CD1a,CD83,HLA-DR) by flow cytometry on the 8th day after cultured. We mixed the DCs from different groups with their autologous T cells, which were cultured with rhIL-2 for cytotoxic T cells (CTLs). We mixed the CTLs from different groups with HL-60 cells. Cytotoxic activities of different groups were measured by LDH assay.Results①All groups attained typical dentritic appearances on 8th day;②The difference of CDla+ cells between the test group and the control group was that the GITAT group was lower than the control group(P=0.028); and the rates of CD83+cells in the test group were both higher than the control group (P,=0.038, P2=0.010 respectively), the GITAT group was higher than the GITA group (P=0.045); the rates of HLA-DR+ cells in the test group were both higher than the control group (P1=0.020, P2=0.010 respectively), the GITAT group was higher than the GITA group (P=0.010)③The HL-60 as the target cells:the result of LDH assay showed that CTL killing activity in test group (GITA and GITAT) were higher than the control group(P=0.022, P=0.010), and killing activity of CTLs in the GITAT group was higher than the GITA group(P=0.034), the difference was significant。Conclusion①DCs loaded with freeze-thawed leukemia antigen are much riper which derive from children with leukemia in complete remission; DCs loaded with freeze-thawed HL-60 antigen induced CTL to develop more effective anti-leukemic immune effect in contrast wth the unloaded group. DCs loaded with freeze-thawed leukemia cells antigen also induced CTL to develop more effective anti-leukemic immune effect in contrast wth the unloaded group.②Thymosin alpha-1 can promoted the maturity of DCs and raised the cytotoxicity of CTL cooperating with rhGM-CSF, rhIL-4 and rhTNF-a. T a 1 can enhance the antigen-presentation ability of DC loaded with leukemia antigen derived from peripheral blood of children with acute leukemia.