Wendel-Hansen V, Tao W, Ericson M, Klein G, Rosén A
Department of Medical Cell Genetics, Karolinska Institutet, Stockholm, Sweden.
Int J Cancer. 1992 Feb 20;50(4):589-92. doi: 10.1002/ijc.2910500417.
Three Epstein-Barr-virus-transformed lymphoblastoid cell lines (LCL) were analysed on the basis of their CD23 expression. Levels of EBV-DNA were compared in the positive and negative subpopulations. Two lines were further analysed with regard to EBNA, cytoplasmic immunoglobulin (cIg) and lytic (EA/VCA) protein expression. Both subpopulations had a similar MHC class-II transcription, but the CD23- subpopulation had a lower plating efficiency and a lower rate of DNA synthesis. In the B6, NAD50 and 0467.3 cell lines, CD23- cells contained 2 +/- 0.2 - 6.4 +/- 3.0 times less EBV DNA than the corresponding CD23+ population. EBNA was expressed in 81 +/- 4.2% - 93 +/- 3.8% of the CD23+ cells and in 0 - 46 +/- 8.0% of the CD23- cells. No CD23+ cells in B6 or NAD50 contained any EA/VCA, while 19 +/- 2.8% - 24 +/- 4.2% of the CD23- cells were positive for the lytic-cycle-associated antigens. Of the CD23- cells, 70 +/- 8.6% - 86 +/- 6.0% were positive for cytoplasmic immunoglobulin compared to 14.7 +/- 2.7% - 14.9 +/- 1.8% in the corresponding CD23+ population. We have previously shown that only 18% of the cIg-positive cells were EBNA-positive in the B6 line compared to 94% in the cIg- population. This was open to 2 alternative interpretations: loss of EBV genomes from a fraction of the cells with subsequent differentiation to secretory immunoglobulin production, or down-regulation of EBNA expression in differentiating, EBV-genome-positive cells. Our present findings speak for the first alternative, indicating that a certain proportion of the cells may lose their EBV genomes in both long-established and freshly transformed LCLs. This is accompanied by a reduced percentage of EBNA-positive cells, the disappearance of at least one activation marker (CD23) associated with the virally induced blast transformation, and an increased synthesis of cIg.
基于CD23表达对三株爱泼斯坦-巴尔病毒转化的淋巴母细胞系（LCL）进行分析。比较了EBV-DNA在阳性和阴性亚群中的水平。对其中两株细胞系进一步分析了EBNA、细胞质免疫球蛋白（cIg）和裂解性（EA/VCA）蛋白的表达。两个亚群具有相似的MHC II类转录水平，但CD23阴性亚群的接种效率较低，DNA合成速率也较低。在B6、NAD50和0467.3细胞系中，CD23阴性细胞所含的EBV DNA比相应的CD23阳性群体少2±0.2至6.4±3.0倍。EBNA在81±4.2%至93±3.8%的CD23阳性细胞中表达，而在0至46±8.0%的CD23阴性细胞中表达。B6或NAD50中没有CD23阳性细胞含有任何EA/VCA，而19±2.8%至24±4.2%的CD23阴性细胞对裂解周期相关抗原有阳性反应。在CD23阴性细胞中，70±8.6%至86±6.0%的细胞对细胞质免疫球蛋白呈阳性，而在相应的CD23阳性群体中这一比例为14.7±2.7%至14.9±1.8%。我们之前已经表明，在B6细胞系中，只有18%的cIg阳性细胞为EBNA阳性，而在cIg阴性群体中这一比例为94%。这有两种可能的解释：一部分细胞丢失EBV基因组，随后分化为分泌免疫球蛋白的细胞；或者在分化的、EBV基因组阳性的细胞中EBNA表达下调。我们目前的研究结果支持第一种解释，表明在长期建立的和新转化的LCL中，一定比例的细胞可能会丢失其EBV基因组。这伴随着EBNA阳性细胞百分比的降低、至少一种与病毒诱导的母细胞转化相关的激活标记（CD23）的消失，以及cIg合成的增加。
