Wang Qiulan, Lu Yuhong, Li Shengpu, Wang Mu, Cai Jiye
Department of Chemistry, Jinan University, Guangzhou 510632, China.
Sheng Wu Gong Cheng Xue Bao. 2011 Jan;27(1):131-6.
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.
B淋巴细胞膜上CD20抗原分子的低表达是B细胞慢性淋巴细胞白血病（B-CLL）的主要特征。在本文中，我们结合激光扫描共聚焦显微镜（LSCM）和量子点标记来检测CD20分子在CD20+B淋巴细胞表面的表达和分布。同时，我们利用原子力显微镜（AFM）研究了正常人和B-CLL患者的B淋巴细胞的形态和超微结构。此外，我们使用用CD20抗体修饰的AFM探针测量了CD20抗原-抗体结合的力谱。荧光图像表明，正常CD20+B淋巴细胞的CD20密度远高于B-CLL CD20+B细胞。AFM数据显示，B-CLL CD20+B淋巴细胞的超微结构变得更加复杂。此外，单分子力谱数据表明，CD20抗原-抗体的特殊力比裸AFM探针与细胞表面之间的非特异性力大四倍。力图谱显示，CD20分子在正常CD20+B淋巴细胞上均匀分布，而在B-CLL CD20+B淋巴细胞上分布不均一。我们的数据为临床上利妥昔单抗治疗反应低的现象提供了可视化证据。同时，AFM有可能成为药理学药物开发和筛选的有力工具。
