Borowski A, van Valen F, Ulbrecht M, Weiss E H, Blasczyk R, Jürgens H, Göbel U, Schneider E M
Immunological Laboratory, Institute of Hemostaseology and Transfusion-Medicine, Düsseldorf University, Germany.
Immunobiology. 1999 Feb;200(1):1-20. doi: 10.1016/s0171-2985(99)80029-1.
In this study, the expression of polymorphic and non-polymorphic MHC antigens in Ewing's tumor (ET) cells was examined by surface staining, Western blots and transcriptional analysis. Cell lines derived from Ewing's tumors largely lack polymorphic HLA class Ia antigens of both the HLA-A and the HLA-B loci but binding of monomorphic HLA antibodies indicates significant expression of HLA-C locus antigens and/or HLA class Ib molecules. HLA Ib molecules encoded by the HLA-E, -F or -G loci with a molecular mass of less than 44 kDa were not detected in lysates of either constitutive or TNF-alpha plus IFN-gamma treated ET cells. Two representative ET cell lines with either detectable HLA-A, -B antigens (A673) or absolutely non-detectable HLA-A, -B antigens (SK-ES-1) were further subjected to transcriptional analysis. A673 mRNA hybridized with HLA-A, -B, -C and HLA-E-specific probes in Northern blots. By contrast, mRNA specific for HLA-A, -B, -C was negative in SK-ES-1 but TNF-alpha plus IFN-gamma reconstituted HLA-A, -B, -C transcription in this cell line. HLA-E was transcribed in A673 but not in SK-ES-1. Combining mRNA and surface expression of HLA class Ia molecules results in a highly variable pattern of defective HLA class I expression in this type of neuroectodermal tumor. The involvement of the ET-specific fusion transcript EWS/Fli-1 in modulating the HLA-A and -B locus antigens is likely to occur by the upregulation of c-myc in these tumors. The exceptionally constant expression of HLA-C or some other non-A, non-B antigens (reactive with defined monoclonal antibodies) implies important consequences on tumor-cell resistance against specific CTL and NK activity in vivo.
在本研究中，通过表面染色、蛋白质免疫印迹和转录分析检测了尤文氏肉瘤（ET）细胞中多态性和非多态性MHC抗原的表达。源自尤文氏肉瘤的细胞系在很大程度上缺乏HLA-A和HLA-B位点的多态性HLA-Ia抗原，但单态性HLA抗体的结合表明HLA-C位点抗原和/或HLA-Ib分子有显著表达。在组成性或TNF-α加IFN-γ处理的ET细胞裂解物中未检测到由HLA-E、-F或-G位点编码的分子量小于44 kDa的HLA-Ib分子。对两个具有可检测的HLA-A、-B抗原（A673）或绝对不可检测的HLA-A、-B抗原（SK-ES-1）的代表性ET细胞系进一步进行转录分析。在Northern印迹中，A673 mRNA与HLA-A、-B、-C和HLA-E特异性探针杂交。相比之下，HLA-A、-B、-C特异性mRNA在SK-ES-1中呈阴性，但TNF-α加IFN-γ可在该细胞系中重建HLA-A、-B、-C转录。HLA-E在A673中被转录，但在SK-ES-1中未被转录。结合HLA-Ia分子的mRNA和表面表达，在这种神经外胚层肿瘤中会导致HLA-I类表达缺陷的高度可变模式。ET特异性融合转录本EWS/Fli-1参与调节HLA-A和-B位点抗原，可能是通过这些肿瘤中c-myc的上调发生的。HLA-C或其他一些非A、非B抗原（与特定单克隆抗体反应）的异常恒定表达意味着对肿瘤细胞在体内抵抗特定CTL和NK活性具有重要影响。
