RESUMO
Objective To study the effect of a new immunomodulator composed of muramyl dipeptide(MDP) and anti-CD10monoclonal antibody(MDP-Ab)on the dendritic cells(DC)of children with acute leukemia. Methods DC was adopted to divide the children with acute lymphoblastic leukemia into 6 groups,including the control group,unconjugated anti-CD10alone,unconjugated MDP alone,MDP-Ab alone,lipopolysaccharide(LPS)alone and MDP-Ab + LPS.The immunophenotypes,the endocytosis interleukin-12(IL-12)were detected.The stimulation index of autologous lymphocytes was assayed by adopting 5-(and 6)-carboxyfluorescein diacetate,succinimidyl es-ter(CFSE)-staining method.The supernatants of DC and autologous lymphocytes were used to detect the level of in-terferon-γ(IFN-γ)by using enzyme-linked immunosorbent assay.Results (1)DC immunophenotype:The ex-pressions of human leukocyte antigen-DR(HLA-DR),mature molecule(CD83)and co-stimulatory molecules (CD80and CD86)were increased significantly upon DC triggered with MDP-Ab,compared with the control group,un-conjugated anti-CD10group,and unconjugated MDP group,but lower than those in LPS and combination of MDP-Ab with LPS(F=629.62,P=0.000).(2)The level of IL-12:a significant increase in IL-12 level was detected in MDP-Ab group,LPS group,and combination of MDP-Ab with LPS group,compared with the control group,uncon-jugated anti-CD10group,and unconjugated MDP group(F=857.87,P=0.000). There were significant differences among the first three groups.(3)Endocytosis assay:The uptake of DCs stimulated by unconjugated anti-CD10,un-conjugated MDP,MDP-Ab immunoconjugate,LPS or combination was lower than that of immature DC in the control group which was(81.3 ± 10.1)%.(4)Mixed lymphocyte reaction and IFN-γ level:DC,treated with MDP-Ab, LPS and combination,stimulated more CFSE positive cells and higher level of IFN-γ secretion than the control group and unconjugated anti-CD10group,unconjugated MDP group. The most significance was observed in combination of MDP-Ab with LPS(F=393.36,P=0.000;F=2 497.18,P=0.000).Conclusion It is concluded that MDP-Ab could promote the proliferation and maturation of DC derived from blood of children with acute leukemia.