B细胞膜CD20抗原的分布与单分子力谱探测  

Distribution and force spectroscopy of CD20 antigen-antibody binding on the B cell surface

作　　者：王秋兰[1] 卢育洪[2] 李盛璞[1] 王牡[1] 蔡继业[1] 

机构地区：[1]暨南大学化学系,广州510632 [2]暨南大学附属第一临床医院血液科,广州510632

出　　处：《生物工程学报》2011年第1期131-136,共6页Chinese Journal of Biotechnology

基　　金：国家重点基础研究发展计划(973计划)(No.2010CB833603);国家自然科学基金(No.30872404)资助~~

摘　　要：CD20抗原分子在B细胞上表达下降是慢性B淋巴细胞白血病(B-CLL)的标志性特征。采用激光扫描共聚焦显微镜(LSCM)和量子点标记相结合的方法对正常和B-CLL外周血CD20+B淋巴细胞膜表面CD20抗原分子的表达及分布进行了荧光成像。同时,采用原子力显微镜(AFM)对CD20+B细胞的形貌及超微结构特征进行了表征,并且将AFM针尖用生物素化的单克隆抗体进行修饰,对CD20+B细胞表面的CD20抗原-抗体之间的单分子力谱进行了探测。LSCM荧光图像显示,B-CLL CD20+B淋巴细胞上CD20分子的表达量比正常CD20+B淋巴细胞显著降低。AFM结果显示,B-CLL CD20+B淋巴细胞超微结构比正常的粗糙。力谱结果显示,CD20抗原-抗体的相互作用力大约是非特异性黏附力的5倍,CD20分子在正常CD20+B淋巴细胞膜上分布比较均匀,小部分有聚集现象,反之,在B-CLL CD20+B淋巴细胞膜表面分布稀疏。利用以上两种方法能进一步观察到B-CLL外周血B淋巴细胞的异常,并在一定程度上解释临床上B-CLL病人对利妥昔的低反应现象,为针对抗原CD20的治疗用药选择提供参考。The lower expression of CD20 antigen molecules on the B cell membrane is the primary characteristic of B-chronic lymphocytic leukemia（B-CLL）.In this paper,we combined laser scanning confocal microscopy（LSCM） and quantum dots labeling to detect the expression and distribution of CD20 molecules on CD20＋B lymphocyte surface.Simultaneously,we investigated the morphology and ultrastructure of the B lymphocytes that belonged to the normal persons and B-CLL patients through utilizing the atomic force microscope（AFM）.In addition,we measured the force spectroscopy of CD20 antigen-antibody binding using the AFM tips modified with CD20 antibody.The fluorescent images indicated that the density of CD20 of normal CD20＋B lymphocytes was much higher than that of B-CLL CD20＋B cells.The AFM data show that ultrastructure of B-CLL CD20＋B lymphocytes became more complicated.Moreover,the single molecular force spectroscopy data show that the special force of CD20 antigen-antibody was four times bigger than the nonspecific force between the naked AFM tip and cell surface.The force map showed that CD20 molecules distributed homogeneously on the normal CD20＋B lymphocytes,whereas,the CD20 molecules distributed heterogenous on B-CLL CD20＋B lymphocytes.Our data provide visualized evidence for the phenomenon of low-response to rituximab therapy on clinical.Meanwhile,AFM is possible to be a powerful tool for development and screening of drugs for pharmacology use.

关 键 词：B-CLL 外周血CD20+B淋巴细胞 CD20分子 LSCM AFM 

分 类 号：R392[医药卫生—免疫学]