Tissue-specific migration pathways by phenotypically distinct subpopulations of memory T cells.
A proportion of T cells recirculate in a tissue-selective manner. Recent studies which showed that the skin-tropic subset of T cells was of memory/activated type, led us to examine whether the preferential homing of T cells to the gut also involved memory T cells, and if so whether these memory T cells were phenotypically distinct from other memory T cells. Lymphocytes migrating through the gut and the skin of sheep was collected by cannulating the lymphatic ducts draining these tissues. Both naive and memory T cells were found to recirculate through the gut, although only memory T cells migrated through the skin. However, when T cells from the gut were labeled with fluorescein isothiocyanate and assessed for their migration back to the gut, it was the memory population which showed a tropism for the gut. Gut-tropic memory T cells migrated poorly through the skin, indicating that these cells were distinct from skin-tropic memory T cells. This was confirmed by phenotypic analysis. Gut memory T cells expressed very low levels of the alpha 6 and beta 1 integrins, in contrast to skin memory T cells which expressed high levels. There was no evidence for heterogeneity within the naive T cell population, which migrated preferentially to lymph nodes. This migration pattern could be explained in part by the high expression of the L-selectin (lymph node homing receptor, LAM-1) on naive T cells, in contrast to memory T cells from gut or skin which were mostly L-selectin negative. These results in sheep indicate that subsets of alpha/beta memory T cells show tissue-selective migration patterns, which probably develop in a particular environment following encounter with antigen.
Basel Institute for Immunology, Switzerland.
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Mackay
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Marston
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Dudler
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Spertini
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Tedder
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Hein
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000502:physiology*; D002465:Cell Movement; D004730:Endothelium, Vascular / Q000502:physiology; D007156:Immunologic Memory; D016023:Integrins / Q000502:physiology*; D007422:Intestines / Q000276:immunology; D019041:L-Selectin; D008198:Lymph Nodes / Q000276:immunology; D010581:Peyer's Patches / Q000276:immunology; D016201:Receptors, Lymphocyte Homing / Q000502:physiology; D012756:Sheep; D012867:Skin / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000502:physiology*
D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D016023:Integrins; D016201:Receptors, Lymphocyte Homing; D019041:L-Selectin