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Proceedings Paper

Polarized T-cell sensitivity to antigen revealed with an optical trap
Author(s): Paul A. Negulescu; Tatiana B. Krasieva; Bruce J. Tromberg; Michael D. Cahalan
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Paper Abstract

T-cell contact with antigen-presenting B cells initiates an activation cascade which includes an increase in T-cell [Ca2+] and leads to T-cell differentiation and proliferation. We evaluated cell-cell contact requirements for T-cell activation by using an optical trap to control the orientation of T-cell/B-cell pairs and fluorescence microscopy to measure subsequent T-cell [Ca2+] responses. B cells were trapped with a titanium-sapphire laser tuned to 760 nm and placed at various locations along the T cells, which had a polarized appearance defined by shape and the direction of crawling. T-cell intracellular [Ca2+] was detected as an emission shift from the combination of fura-red and fluo-3, two cytoplasmic [Ca2+] indicators. T cells which were presented antigen at the leading edge had a higher probability of responding (84% vs. 31%) and a shorter latency of response (42 s vs. 143 s) than those contacting B cells with their trailing end. Similar results were obtained using beads coated with antibodies to the T-cell receptor. These findings demonstrate a role for initial T-cell/B-cell contact geometry in T-cell activation by showing that the T cell is a polarized antigen sensor.

Paper Details

Date Published: 10 May 1996
PDF: 6 pages
Proc. SPIE 2678, Optical Diagnostics of Living Cells and Biofluids, (10 May 1996); doi: 10.1117/12.239501
Show Author Affiliations
Paul A. Negulescu, Beckman Laser Institute and Medical Clinic (United States)
Tatiana B. Krasieva, Beckman Laser Institute and Medical Clinic (United States)
Bruce J. Tromberg, Beckman Laser Institute and Medical Clinic (United States)
Michael D. Cahalan, Beckman Laser Institute and Medical Clinic (United States)


Published in SPIE Proceedings Vol. 2678:
Optical Diagnostics of Living Cells and Biofluids
Daniel L. Farkas; Robert C. Leif; Alexander V. Priezzhev; Toshimitsu Asakura; Bruce J. Tromberg, Editor(s)

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