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Proceedings Paper

Mapping the polarity for T-cell activation with an optical trap
Author(s): Xunbin Wei; Tatiana B. Krasieva; Zhanxiang Zhang; Paul A. Negulescu; Chung-Ho Sun; Michael D. Cahalan; Bruce J. Tromberg
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Paper Abstract

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.

Paper Details

Date Published: 29 April 1998
PDF: 6 pages
Proc. SPIE 3260, Optical Investigations of Cells In Vitro and In Vivo, (29 April 1998); doi: 10.1117/12.307111
Show Author Affiliations
Xunbin Wei, Beckman Laser Institute and Medical Clinic and Univ. of California/Irvine (United States)
Tatiana B. Krasieva, Beckman Laser Institute and Medical Clinic (United States)
Zhanxiang Zhang, Beckman Laser Institute and Medical Clinic (United States)
Paul A. Negulescu, Univ. of California/Irvine (United States)
Chung-Ho Sun, Beckman Laser Institute and Medical Clinic (United States)
Michael D. Cahalan, Univ. of California/Irvine (United States)
Bruce J. Tromberg, Beckman Laser Institute and Medical Clinic and Univ. of California/Irvine (United States)


Published in SPIE Proceedings Vol. 3260:
Optical Investigations of Cells In Vitro and In Vivo
Robert C. Leif; Daniel L. Farkas; Robert C. Leif; Bruce J. Tromberg, Editor(s)

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