反义肽核酸对树突状细胞CD86表达的抑制作用

目的 探讨CD86mRNA反义肽核酸（peptide nucleic acid,PNA)阻断树突状细胞CD86表达和第二信号传递的可能作用。方法 采用激光共聚焦显微镜研究生物素化PNA的细胞内化；利用流式细胞术，荧光细胞组织化学以及RT-PCR研究CD86反义PNA对CD86分子表达的抑制作用，结果 （1）激光共聚焦显微镜光学细胞切片证明，培养的人未成熟树突状细胞能够有效内化生物素化PNA。（2）流式细胞术和荧光细胞组织化学证实CD86反义PNA在蛋白质水平上对CD86分子表达有抑制作用。（3）RT-PCR证明反义PNA能够抑制DCCD86mRNA水平。结论 CD86反义PNA能够抑制人树突状细胞CD86mRNA的表达，从而为进一步利用反义PNA阻断第二信号传递，诱导免疫耐受奠定了基础。

Antisense inhibition of gene expression in human dendritic cells by peptide nucleic acid against CD86]

OBJECTIVE: Dendritic cells (DCs) are the most potent antigen presenting cells (APCs) of the immune system. We intent to block the expression of CD86 in DCs using antisense peptide nucleic acids (PNA), a novel synthetic structural DNA mimic, and interrupt the second signal transmission so that a suppression of corresponding T cell function can be achieved. METHODS: Human DCs grown up from peripheral blood monocytes in GM-CSF and IL-4 were collected. We investigated antisense PNA internalization with laser scan confocal microscope (LSCM). Fluorescence immunocytochemistry, flow cytometry and RT-PCR were used to determine the expression of CD86 protein and mRNA in DCs. RESULTS: LSCM proved that cultured immature DCs could internalized PNA efficiently, according to the specific internalization property of the immature DCs. Antisense PNA DC exhibited striking reductions in cell surface staining for CD86, but not MHC class II, and were poor stimulators of T cell proliferation. RT-PCR found that PNA depressed the amounts of CD86 mRNA in DCs. CONCLUSION: Antisense PNA against CD86 could inhibit the expression of CD86 mRNA and protein in DCs. The blockade of B7/CD28 pathway may increase the potential of costimulatory molecule-deficient antisense PNA DCs of donor origin to induce long-lasting allograft survival.