Kraïba R, Loiseau P, Faille A, Poirier O, Piatier-Tonneau D, Degos L, Abita J P, Charron D
Unité INSERM 204, Cinétique des Populations Cellulaires en Hématologie et Cancérologie, Hôpital Saint-Louis, Paris, France.
Leukemia. 1989 May;3(5):386-93.
We studied peripheral blood lymphocytes (PBL) of eight B chronic lymphocytic leukemia (CLL) patients for the expression of the human leucocyte antigens, HLA-DR and HLA-DQ. Cell surface expression of HLA class II epitopes was analyzed by fluorescent activated cell sorter (FACS) using three monomorphic anti-HLA class II monoclonal antibodies (mAb) specific for DR (D1.12) and DQ (TU22, L2) and a polymorphic anti-DQ (G2A5). The DR and DQ molecules were characterized by two-dimensional gel electrophoresis (2D-PAGE) of the specific immunoprecipitates from biosynthetically labeled cells. DR, DQ specific probes were used to characterize the class II transcripts of the corresponding genes. The data obtained with immunofluorescence disclosed two distinct patterns of HLA class II expression leading to two cell surface phenotypes: (DR+DQ+) and (DR+DQ-). In all cases the cells expressed normal amounts of HLA-DR gene products in terms of mRNA. DR cell surface determinants were present in more than 80% of cells in every sample. By 2-D gel analysis DR proteins disclosed the normal classical pattern associating the alpha, beta, and invariant chain gamma with normal level of biosynthesis for alpha and gamma but decreased biosynthesis for one of the beta gene products. Moreover, the three chains demonstrated defect in glycosylation process. In half of the cases studied the cells lacked DQ molecules at the cell surface. DQ alpha and DQ beta transcripts were detected in all cases, although the amount was extremely low in one case. DQ proteins were variable in the DQ+ phenotype and absent in the DQ- one. Interestingly, TPA and rIFN gamma treatment could restore normal glycosylation process of the DR isotype and increase biosynthesis of DQ alpha and beta chains. Those combined results support the view that transcriptional, post-transcriptional, and posttranslational mechanisms underlie the heterogeneity of class II expression observed in CLL. Moreover, 2-D gel analysis may be an invaluable tool for the analysis of the biosynthetic process of class II molecules.
我们研究了8例B细胞慢性淋巴细胞白血病（CLL）患者外周血淋巴细胞（PBL）中人白细胞抗原HLA - DR和HLA - DQ的表达情况。使用三种针对DR（D1.12）和DQ（TU22、L2）的单态抗HLA - II类单克隆抗体（mAb）以及一种多态抗DQ（G2A5），通过荧光激活细胞分选仪（FACS）分析HLA - II类表位的细胞表面表达。通过对生物合成标记细胞的特异性免疫沉淀产物进行二维凝胶电泳（2D - PAGE）来鉴定DR和DQ分子。使用DR、DQ特异性探针来鉴定相应基因的II类转录本。免疫荧光获得的数据揭示了HLA - II类表达的两种不同模式，导致两种细胞表面表型：（DR + DQ +）和（DR + DQ -）。在所有情况下，就mRNA而言，细胞表达正常量的HLA - DR基因产物。每个样本中超过80%的细胞存在DR细胞表面决定簇。通过二维凝胶分析，DR蛋白显示出正常的经典模式，即α、β和恒定链γ相关联，α和γ的生物合成水平正常，但其中一种β基因产物的生物合成减少。此外，这三条链在糖基化过程中表现出缺陷。在所研究的病例中，一半病例的细胞在细胞表面缺乏DQ分子。在所有病例中均检测到DQα和DQβ转录本，尽管在一个病例中的量极低。DQ蛋白在DQ +表型中可变，在DQ -表型中不存在。有趣的是，佛波酯（TPA）和重组干扰素γ（rIFNγ）处理可恢复DR同种型的正常糖基化过程，并增加DQα和β链的生物合成。这些综合结果支持这样一种观点，即转录、转录后和翻译后机制是CLL中观察到的II类表达异质性的基础。此外，二维凝胶分析可能是分析II类分子生物合成过程的一种非常有价值的工具。
