Division of Plastic, Reconstructive and Aesthetic Surgery, Department of Surgery, The Chinese University of Hong Kong, Hong Kong, SAR.
Department of Obstetrics and Gynaecology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, SAR.
Cytotherapy. 2014 May;16(5):631-9. doi: 10.1016/j.jcyt.2013.10.008. Epub 2013 Dec 22.
Our previous study has demonstrated the stem cell-like properties of human umbilical cord lining epithelial cells (CLECs) and their capability for epidermal reconstitution in organotypic skin culture; however, the immunogenicity of these cells has not been clearly defined. We assessed several aspects of the immune properties of CLECs in vitro.
We examined CLECs for their immunoregulatory function in a mixed lymphocyte culture experiment. We characterized the expression patterns of the major histocompatibility complex (MHC), co-stimulatory molecules and the pro-/anti-inflammatory cytokines and growth factors in CLECs by means of reverse transcription-polymerase chain reaction, Western blotting, flow cytometry and FlowCytomix multiple analyte detection assays.
CLECs were found not to induce but to suppress the proliferation response of the peripheral blood mononuclear cells in a mixed lymphocyte culture assay. They did not express the MHC class II antigen HLA-DR but the non-classic MHC class I antigens HLA-G and HLA-E and lacked the expression of the co-stimulatory molecules CD40, CD80 and CD86. In addition, they produced less interleukin-1β and transforming growth factor-β1 but more interleukin-4 and hepatocyte growth factor than did adult keratinocytes, a pattern in favor of wound healing with less inflammation response.
Our data suggest that CLECs have an immunosuppressive function in addition to their low immunogenicity. This could be at least partially explained by their expression of HLA-G and HLA-E molecules associated with immune tolerance and absence of HLA-DR and co-stimulatory molecules. The demonstration that CLECs produce a favorable pattern of cytokines and growth factors for wound healing provides further support for their potential clinical application in allogeneic cell therapy.
我们之前的研究已经证明了人脐带衬里上皮细胞（CLECs）的干细胞样特性及其在器官型皮肤培养中表皮重建的能力；然而，这些细胞的免疫原性尚未明确界定。我们评估了 CLECs 体外免疫特性的几个方面。
我们在混合淋巴细胞培养实验中检查了 CLECs 的免疫调节功能。我们通过逆转录-聚合酶链反应、Western blot、流式细胞术和 FlowCytomix 多分析物检测分析，表征了 CLECs 中主要组织相容性复合体（MHC）、共刺激分子以及促炎/抗炎细胞因子和生长因子的表达模式。
在混合淋巴细胞培养实验中，我们发现 CLECs 不会诱导外周血单个核细胞增殖反应，而是抑制其增殖反应。它们不表达 MHC Ⅱ类抗原 HLA-DR，但表达非经典 MHC Ⅰ类抗原 HLA-G 和 HLA-E，并且缺乏共刺激分子 CD40、CD80 和 CD86 的表达。此外，它们产生的白细胞介素-1β和转化生长因子-β1 较少，但白细胞介素-4 和肝细胞生长因子较多，与炎症反应较少的伤口愈合模式一致。
我们的数据表明，除了低免疫原性外，CLECs 还具有免疫抑制功能。这至少部分可以通过它们表达与免疫耐受相关的 HLA-G 和 HLA-E 分子以及缺乏 HLA-DR 和共刺激分子来解释。CLECs 产生有利于伤口愈合的细胞因子和生长因子的模式，为它们在同种异体细胞治疗中的潜在临床应用提供了进一步的支持。
