AFM‐ and NSOM‐based force spectroscopy and distribution analysis of CD69 molecules on human CD4+ T cell membrane |
| |
Authors: | Mingqian Hu Jianan Chen Jiongkun Wang Xiaoping Wang Shuyuan Ma Jiye Cai Crystal Y Chen Zheng W Chen |
| |
Institution: | 1. Department of Chemistry, Jinan University, Guangzhou, Guangdong 510632, China;2. Institution for Tissue Transplantation and Immunology, Jinan University, Guangzhou, Guangdong 510632, China;3. Department of Microbiology & Immunology, Center for Primate Biomedical Researchl, University of Illinois, College of Medicine, Chicago, IL 60612, USA |
| |
Abstract: | Although CD69 is well known as an early T cell‐activation marker, the possibility that CD69 are distributed as nano‐structures on membrane for immune regulation during T cell activation has not been tested. In this study, nanoscale features of CD69 expression on activated T cells were determined using the atomic force microscopy (AFM) topographic and force‐binding nanotechnology as well as near‐field scanning optical microscopy (NSOM)‐/fluorescence quantum dot (QD)‐based nanosacle imaging. Unstimulated CD4+ T cells showed neglectable numbers of membrane CD69 spots binding to the CD69 Ab‐functinalized AFM tip, and no detectable QD‐bound CD69 as examined by NSOM/QD‐based imaging. In contrast, Phytohemagglutinin (PHA)‐activated CD4+ T cells expressed CD69, and displayed many force‐binding spots binding to the CD69 Ab‐functionalized AFM tip on about 45% of cell membrane, with mean binding‐rupture forces 276 ± 71 pN. Most CD69 molecules appeared to be expressed as 100–200 nm nanoclusters on the membrane of PHA‐activated CD4+ T cells. Meanwhile, NSOM/QD‐based nanoscale imaging showed that CD69 were non‐uniformly distributed as 80–200 nm nanoclusters on cell‐membrane of PHA‐activated CD4+ T cells. This study represents the first demonstration of the nano‐biology of CD69 expression during T cell activation. Copyright © 2009 John Wiley & Sons, Ltd. |
| |
Keywords: | atomic force microscopy (AFM) near‐field scanning optical microscopy (NSOM) CD69 molecular force spectroscopy distribution |
|
|