Skip to main content
eScholarship
Open Access Publications from the University of California

UC Irvine

UC Irvine Previously Published Works bannerUC Irvine

Mapping the polarity for T-cell activation with an optical trap

Published Web Location

https://doi.org/10.1117/12.307111Creative Commons 'BY' version 4.0 license
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 fluorescence 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.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View