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Proceedings Paper

Action of the photosensitizer QLT0074 upon human T lymphocytes in vitro
Author(s): David W. C. Hunt; Huijun Jiang; Ruth A. Salmon; David J. Granville; John R. North; Anna M. Richter
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Paper Abstract

A new photosensitizer, presently designated QLT0074, may be useful for the treatment of skin conditions, particularly those mediated by T lymphocytes, with photodynamic therapy (PDT). QLT0074 was tested against human peripheral blood T cells and Jurkat T lymphoma cells. Low concentrations of QLT0074 and blue light were sufficient to induce apoptosis in peripheral blood T cells or Jurkat T lymphoma cells as indicated by expression of the apoptosis-associated mitochondrial 7A6 marker, annexin-V labeling or activation of capsase-3 and cleavage of the capsase substrate poly(ADP-ribose)polymerase (PARP). Flow cytometry studies performed following PDT showed that peripheral blood T cells with high expression of the interleukin-2 receptor (CD25) took up greater amounts of QLT0074 and were eliminated to a greater degree than T cells with low CD25 levels. This effect of PDT was also shown by the reduction in the percentage of T cells that expressed other activation-associated markers such as very late activation antigen-4 (CD49d), human leukocyte antigen DR (HLA-DR), intercellular adhesion molecule-1 (CD54) and Fas (CD95). In the case of T cells that remained viable following PDT, CD25 expression was lower while CD54, CD95 and HLA-DR levels were unchanged. Thus, PDT with QLT0074 has selective, dose-dependent effects on T cells in vitro.

Paper Details

Date Published: 9 April 2001
PDF: 18 pages
Proc. SPIE 4248, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy X, (9 April 2001); doi: 10.1117/12.424443
Show Author Affiliations
David W. C. Hunt, QLT, Inc. (Canada)
Huijun Jiang, QLT, Inc. (Canada)
Ruth A. Salmon, QLT, Inc. (Canada)
David J. Granville, QLT, Inc. (Canada)
John R. North, QLT, Inc. (Canada)
Anna M. Richter, QLT, Inc. (Canada)

Published in SPIE Proceedings Vol. 4248:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy X
Thomas J. Dougherty, Editor(s)

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