脂肪干细胞HLA分子表达与体外抑制淋巴细胞增殖的实验研究

目的研究脂肪干细胞(adiposederivedstemcells,ADSCs)表面免疫分子的表达以及体外调节淋巴细胞反应的功能,以期为组织工程提供同种异体种子细胞来源。方法从临床脂肪抽吸术丢弃脂肪组织中分离获取脂肪干细胞(共3例),体外培养至第2代,流式细胞仪检测免疫分子HLAI、HLAII的表达。1×105个/孔ADSC细胞刺激异体淋巴细胞,观察细胞增殖情况。以植物血凝素(PHA,2μg/ml)刺激淋巴细胞后,分别以(1×102、1×103、1×104、1×105)细胞/孔数量的异体脂肪干细胞加入反应体系中,观察淋巴细胞增殖情况;另一组在刺激同时加入白介素2(IL2,0.5ng/ml),检测脂肪干细胞抑制作用的逆转。分别以1×102～5细胞/孔数量的“第三者”脂肪干细胞或经IFNγ作用后脂肪干细胞加入混合双向淋巴细胞反应体系中,观察淋巴细胞增殖抑制情况。结果脂肪干细胞表达HLAI类分子,但未检测到HLAII类分子阳性表达。人IFNγ刺激48h后,HLAI表达未见明显增高,HLAII类分子表达明显增高。异体或经IFNγ作用的脂肪干细胞均未能刺激淋巴细胞体外增殖。脂肪干细胞可明显抑制PHA刺激的淋巴细胞增殖,IL2可逆转脂肪干细胞的抑制作用。脂肪干细胞可明显抑制双相混合淋巴细胞反应,抑制作用呈脂肪干细胞细胞数量依赖性;经IFNγ作用后抑制作用未见明显减弱。结论ADSC可在体外抑制淋巴细胞增殖反应,具有一定的调节淋巴细胞反应的能力,有可能成为组织工程或细胞治疗中同种异体细胞来源。

Human adipose derived stem cells suppress lymphocyte proliferation induced by cellular or nonspecific mitogenic stimuli

OBJECTIVE: To study immunological properties of adipose derived stem cells (ADSC) and their in vitro immunomodulatory effects on lymphocytes. METHODS: ADSC was isolated from fat tissue by liposuction and culture expanded. Cells at passage 2 were observed for the expression of HLAI, HLAII by FACs analysis. Peripheral blood lymphocytes (PBL) were cultured with allogeneic ADSCs at dose of 1 x 10(5). A third-party ADSCs at dose of 1 x 10(2), 1 x 10(3), 1 x 10(4), 1 x 10(5) were added to the ongoing two-way mixed lymphocyte reactions (MLR) for 6 days. Value of CPM (count per minute) was calculated with luminenscence counter. RESULTS: Flow cytometry showed that undifferentiated ADSCs express HLA class I but not class II. Addition of interferon gamma (IFN-gamma) for 48 hours induced greater than 90% of cells to express HLA class II. No lymphocyte response was induced by allogeneic ADSCs as stimulators. Results were similar using ADSCs pretreated with IFN-gamma. ADSCs elicited inhibit function of mixed lymphocyte cultures in a dose dependent way. Even if ADSCs were pretreated with IFN-gamma, the suppression ability was maintained. CONCLUSION: Undifferentiated ADSCs do not elicit alloreactive lymphocyte proliferative responses and could modulate immune responses in vitro.