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Thymocyte-dendritic cell interactions near sources of CCR7 ligands in the thymic cortex

Item Type:Article
Title:Thymocyte-dendritic cell interactions near sources of CCR7 ligands in the thymic cortex
Creators Name:Ladi, E. and Schwickert, T.A. and Chtanova, T. and Chen, Y. and Herzmark, P. and Yin, X. and Aaron, H. and Chan, S.W. and Lipp, M. and Roysam, B. and Robey, E.A.
Abstract:Little is known about the dynamics of the interactions between thymocytes and other cell types, as well as the spatiotemporal distribution of thymocytes during positive selection in the microenvironment of the cortex. We used two-photon laser scanning microscopy of the mouse thymus to visualize thymocytes and dendritic cells (DCs) and to characterize their interactions in the cortex. We show that thymocytes make frequent contacts with DCs in the thymic cortex and that these associations increase when thymocytes express T cell receptors that mediate positive selection. We also show that cortical DCs and the chemokine CCL21 expression are closely associated with capillaries throughout the cortex. The overexpression of the chemokine receptor CCR7 in thymocytes results in an increase in DC-thymocyte interactions, while the loss of CCR7 in the background of a positive-selecting TCR reduces the extent of DC-thymocyte interactions. These observations identify a vasculature-associated microenvironment within the thymic cortex that promotes interactions between DCs and thymocytes that are receiving positive selection signals.
Keywords:Apoptosis, Capillaries, Cell Communication, Cell Movement, Chemokine CCL21, Dendritic Cells, Fluorescent Antibody Technique, Histocompatibility Antigens Class I, Computer-Assisted Image Processing, In Situ Nick-End Labeling, Confocal Microscopy, T-Cell Antigen Receptors, CCR7 Receptors, Self Tolerance, T-Lymphocytes, Thymus Gland, Animals, Mice
Source:Journal of Immunology
Publisher:American Association of Immunologists (U.S.A.)
Page Range:7014-7023
Date:15 November 2008
Official Publication:http://www.jimmunol.org/cgi/content/abstract/181/10/7014
PubMed:View item in PubMed

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