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29 April 1998 Mapping the polarity for T-cell activation with an optical trap
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Proceedings Volume 3260, Optical Investigations of Cells In Vitro and In Vivo; (1998)
Event: BiOS '98 International Biomedical Optics Symposium, 1998, San Jose, CA, United States
In the body, individual T helper lymphocytes need to be activated first by physical contact with antigen-presenting cells (APC). T-cell contact with APCs initiates an activation cascade which includes an increase in T-cell intracellular calcium and leads to T-cell proliferation and differentiation. We have combined fluroescence spectroscopy and imaging with optical manipulation to investigate the physical properties of T-cell activation. We study cell-cell contact requirements for T-cell activation using optical tweezers to control the orientation of T-cell/APC pairs and fluorescence microscopy to measure the subsequent T-cell intracellular calcium level ([Ca2+]i) response. APCs or beads coated with antibodies to the T-cell receptor are trapped with a near- infrared titanium-sapphire laser and placed at different locations along the T-cell, which has a polarized appearance defined by the shape and direction of crawling. T cells which are presented with antigen at the leading edge have a higher probability of responding and a shorter latency of response than those contacting APCs or beads with their trailing end. Alterations in antibody density and bead size are used to determine the spatial requirements for T cell activation and the minimum number of receptors which must be engaged in order to transmit a positive signal.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Xunbin Wei, Tatiana B. Krasieva, Zhanxiang Zhang, Paul A. Negulescu, Chung-Ho Sun, Michael D. Cahalan, and Bruce J. Tromberg "Mapping the polarity for T-cell activation with an optical trap", Proc. SPIE 3260, Optical Investigations of Cells In Vitro and In Vivo, (29 April 1998);

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