AFM- and NSOM-based force spectroscopy and distribution analysis of CD69 molecules on human CD4+ T cell membrane

✍ Scribed by Mingqian Hu; Jianan Chen; Jiongkun Wang; Xiaoping Wang; Shuyuan Ma; Jiye Cai; Crystal Y. Chen; Zheng W. Chen

• Book ID: 102376214
• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 295 KB
• Volume: 22
• Category: Article
• ISSN: 0952-3499
• DOI: 10.1002/jmr.976

✦ Synopsis

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.