K562细胞外泌体诱导特异性CTL生成的研究

为了研究人白血病细胞株K562细胞分泌的外泌体（exosomes）及K562细胞总RNA刺激人树突状细胞（DC）分泌的外泌体能否诱导出K562细胞特异性CTL，采用四步离心法提取K562细胞及K562细胞总RNA刺激人树突状细胞的培养上清液中的外泌体，并诱导CTL生成，以四甲基偶氮唑蓝（MTT）法检测CTL对K562细胞的杀伤作用。结果显示：K562细胞外泌体和K562细胞RNA刺激的DC和外泌体均能明显促进对K562细胞的杀伤活性，与未经外泌体作用的对照组相比有显著性差异（P〈0．05）。外泌体作用后对K562细胞的杀伤作用明显比对HL-60细胞的杀伤作用强，其差异有显著性（P〈0．05）。结论：K562细胞外泌体能够诱导出特异性抗白血病细胞的免疫反应。

Production of Specific CTL Induced by Exosomes Derived from K562 Cells

The aim of this study was to investigate whether exosomes derived from K562 cells and human monocyte-derived dendritic cells (DCs) transfected with total RNA of K562 cells are capable of inducing antigen-specific cytotoxic T lymphocytes (CTL) responses in vitro. DCs were generated from peripheral blood mononuclear cells (PBMNC) of healthy volunteers in the presence of GM-CSF and IL-4, and then were transfected with K562 RNA by using DOTAP lipofection. Exosomes was extracted from the supernatant of DCs and K562 cells. The T cell were activated to be tumor specific CTL after DCs and exosomes were co-cultured with autologous T cells derived from healthy volunteers' PBMNC. The effect of CTL on K562 cells was detected by MTT assay. The results showed that treatment of T cells with exosomes derived from K562 cells or DCs transfected with total RNA of K562 cells could significantly promote their killing ability on K562 cells as compared with untreated T cells (P < 0.05). The killing ability of T cells treated with exosomes on K562 cells was stronger than on HL-60 cells (P < 0.05). It is concluded that the specific CTL immune response to leukemia cells can be induced by exosomes derived from K562 cells.