Piller F, Le Deist F, Weinberg K I, Parkman R, Fukuda M
La Jolla Cancer Research Foundation, California 92037.
J Exp Med. 1991 Jun 1;173(6):1501-10. doi: 10.1084/jem.173.6.1501.
The only molecular defect reported for the X-linked immunodeficiency Wiskott-Aldrich syndrome (WAS) is the abnormal electrophoretic behavior of the major T lymphocyte sialoglycoprotein CD43. Since the 70 to 80 O-linked carbohydrate chains of CD43 are known to influence markedly its electrophoretic mobility, we analyzed the structure and the biosynthesis of O-glycans of CD43 in lymphocytes from patients with WAS. Immunofluorescence analysis with the carbohydrate dependent anti-CD43 antibody T305 revealed that in 10 out of the 12 WAS patients tested increased numbers of T lymphocytes carry on CD43 an epitope which on normal lymphocytes is expressed only after activation. Other activation antigens were absent from WAS lymphocytes. Western blots of WAS cell lysates displayed a high molecular mass form of CD43 which reacted with the T305 antibody and which could be found on in vivo activated lymphocytes but was absent from normal unstimulated lymphocytes. To examine the O-glycan structures, carbohydrate labeled CD43 was immunoprecipitated and the released oligosaccharides identified. WAS lymphocyte CD43 was found to carry predominantly the branched structure NeuNAc alpha 2----3Gal beta 1----3 (NeuNAc alpha 2----3Gal beta 1----4G1cNAc beta 1----6) GalNAcOH whereas normal lymphocytes carry the structure NeuNAc alpha 2----3Gal beta 1----3 (NeuNAc alpha 2----6) GalNAcOH. Only after activation NeuNAc alpha 2----3Gal beta 1----3 (NeuNAc alpha 2----3Gal beta 1----4GlcNAc beta 1----6) GalNAcOH becomes the principal oligosaccharide on CD43 from normal lymphocytes. Analyzing the six glycosyltransferases involved in the biosynthesis of these O-glycan structures it was found that in WAS lymphocytes high levels of beta 1----6 N-acetyl-glucosaminyl transferase are responsible for the expression of NeuNAc alpha 2----3Gal beta 1----3 (NeuNAc alpha 2----3Gal beta 1----4GlcNAc beta 1----6) GalNAcOH on CD43. The gene responsible for WAS has not yet been identified but the results presented in this study suggest that the primary defect in WAS may affect a gene which is involved in the regulation of O-glycosylation.
对于X连锁免疫缺陷威斯科特-奥尔德里奇综合征（WAS），所报道的唯一分子缺陷是主要T淋巴细胞唾液酸糖蛋白CD43异常的电泳行为。由于已知CD43的70至80条O-连接碳水化合物链会显著影响其电泳迁移率，我们分析了WAS患者淋巴细胞中CD43的O-聚糖结构及生物合成。用碳水化合物依赖性抗CD43抗体T305进行免疫荧光分析显示，在12名接受检测的WAS患者中，有10名患者体内携带CD43的T淋巴细胞数量增加，其携带的一个表位在正常淋巴细胞中仅在激活后才表达。WAS淋巴细胞中不存在其他激活抗原。WAS细胞裂解物的蛋白质免疫印迹显示出一种高分子量形式的CD43，它能与T305抗体发生反应，这种形式可在体内激活的淋巴细胞中找到，但在正常未受刺激的淋巴细胞中不存在。为了检测O-聚糖结构，对碳水化合物标记的CD43进行免疫沉淀，并对释放的寡糖进行鉴定。结果发现，WAS淋巴细胞的CD43主要携带分支结构NeuNAcα2----3Galβ1----3（NeuNAcα2----3Galβ1----4G1cNAcβ1----6）GalNAcOH，而正常淋巴细胞携带的结构是NeuNAcα2----3Galβ1----3（NeuNAcα2----6）GalNAcOH。正常淋巴细胞的CD43只有在激活后，NeuNAcα2----3Galβ1----3（NeuNAcα2----3Galβ1----4GlcNAcβ1----6）GalNAcOH才会成为主要的寡糖。分析参与这些O-聚糖结构生物合成的六种糖基转移酶后发现，在WAS淋巴细胞中，高水平的β1----6 N-乙酰葡糖胺基转移酶导致了CD43上NeuNAcα2----3Galβ1----3（NeuNAcα2----3Galβ1----4GlcNAcβ1----6）GalNAcOH的表达。导致WAS的基因尚未确定，但本研究给出的结果表明，WAS的原发性缺陷可能影响一个参与O-糖基化调节的基因。
