title: [Distribution and force spectroscopy of CD20 antigen-antibody binding on the B cell surface].
abstract: 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.
authors.affiliation: Department of Chemistry, Jinan University, Guangzhou 510632, China.
authors.forename: Qiulan
authors.initials: Q
authors.lastname: Wang
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Lu
authors.forename: Shengpu
authors.initials: S
authors.lastname: Li
authors.forename: Mu
authors.initials: M
authors.lastname: Wang
authors.forename: Jiye
authors.initials: J
authors.lastname: Cai
mesh_terms: D000937:Antigen-Antibody Reactions / Q000276:immunology*; D018951:Antigens, CD20 / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000648:ultrastructure*; D001666:Binding Sites, Antibody; D002462:Cell Membrane / Q000276:immunology; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000276:immunology*; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D045663:Quantum Dots
chemical_list: D018951:Antigens, CD20