CⅡTA基因在五种人类恶性血液病细胞株细胞中的表达及意义

Expression of CⅡTA gene in five human malignant hematological cell lines and its significance

目的:探讨5种血液病细胞株细胞的HLA-Ⅱ类抗原表达,以及对IFN-γ诱导HLA分子表达的反应性与MHCⅡ类分子反式激活因子(CⅡTA)表达的关系。方法:采用流式细胞术和免疫组化法检测肿瘤细胞HLA分子及CⅡTA蛋白的表达,RT-PCR检测肿瘤细胞CⅡTA基因表达。混合淋巴细胞反应检测肿瘤细胞刺激外周血T细胞反应的能力。结果:肿瘤细胞HLAⅡ类分子表达与CⅡTA表达一致;结构型或诱导型表达CⅡTA的肿瘤细胞,经IFN-γ作用后其HLAⅠ、Ⅱ类抗原表达增高;IFN-γ诱导后仍不表达CⅡTA的肿瘤细胞,其对IFN-γ促HLAⅡ表达的作用不反应。Jurkat诱导后刺激T细胞表达高水平的IL-2mRNA。结论:某些恶性血液病细胞株细胞对IFN-γ不能诱导HLA分子表达与CⅡTA诱导型表达缺陷有关,表明CⅡTA参与调控肿瘤细胞HLAⅠ、Ⅱ类抗原表达,可能在肿瘤免疫逃逸中起重要作用。

Objective： To investigate the role of MHC class Ⅱ Transactivator （C Ⅱ TA） in expression of HLA molecules in five human malignant hematological cell lines. Methods： The expressions of HLA molecules and C Ⅱ TA protein were detected by immunoihistochemistry and flow cytometry. The expression of C Ⅱ TA gene wasdetected by RT-PCR. The response of peripheral T cells after stimulation by Jurkat cells was detected by mixed lymphocyte reaction. Results： The HLA Ⅱ-positive tumor cells expressed the C Ⅱ TA and IFN-γ induced the expression of HLA I , Ⅱ in tumor cells,which were able to express C Ⅱ TA constitutively. Conclusion： There is a correlation between the inability of the tumor cells in response to IFN-γ for HLA expression and the deficiency inthe in ducible expression of C Ⅱ TA.