Experimental Study on Immune Tolerance Induced by Semi-mature Dendritic Cells with MyD88 siRNA Transfection

Objective To investigate the phonetype and tolerogenic function of semi-mature dendritic cells (DC) transfected by myeloid differentiation marker 88(MyD88) small interfering ribonucleic acid(siRNA). Methods Bone marrow of BALB/c mice was inoculated and cultured in vitro,and induced into DC by 10ng/ml recombinated granulocyte macrophage colony stimulating factor (rmGM-CSF) ,then DC was divided into three groups at the 8th day: blank control group: added nothing; lipopolysaccharide (LPS)group: added with 1μg/ml LPS; and experimental group: added with 1μg/ml LPS after transfected by MyD88 siRNA for 4 hours. The phonetype of three groups was analysed by fluorescence-activated cell sorting (FACS). The concentration of interleukin 10(IL-10)and interleukin 12(IL-12) in culture supernatant was detected by enzyme linked immunosorbent assay(ELISA).The function of stimulating alloreactive T cell proliferation were evaluated by primary and secondary mixed lymphocyte reaction (MLR). The cardiac allograft survival time was compared after DC of three groups injected into recipient mice. Results The phonetype of blank control group DC was CD11c+,CD25-,CD40low,CD80low,CD86low,MHC-Ⅱlow, which could be induced to mature DC by LPS. Experimental group DC was phonetypically semi-mature DC (CD11c+,CD25-,CD40mid,CD80low,CD86low,MHC-Ⅱmid) and the IL-10/IL-12 ratio of semi-mature DC increases significantly. Hyporesponsiveness of alloactive T cells can be induced by experimental group DC and the survive time of heart allograft was prolonged. Conclusion Immature DC could become semi-mature DC after transfected by MyD88 siRNA and stimulation by LPS. These semi-mature DC are more tolerogenic than immature DC.