Thy-1 supports adhesion of mouse thymocytes to thymic epithelial cells through a Ca2(+)-independent mechanism.
The aim of this study was to explore whether Thy-1, like other members of the Ig-like superfamily (e.g., CD2 and neural cell adhesion molecule), participates in cell-cell adhesion. This was investigated by measuring the binding of Thy-1+ probe cells (thymocytes or AKR1 T lymphoma cells) to Thy-1- cloned mouse thymic epithelial (MTE) cells using a quantitative cell adhesion assay. The results were as follows: (a) the thymo-epithelial cell interaction was found to be inhibitable (by 25-40%) by soluble Thy-1 molecules purified from phosphatidylinositol-specific phospholipase C-treated mouse thymocytes as well as by Fab' fragments of a Thy-1-specific mAb; (b) the binding of the Thy-1- AKR1 (Thy-1-d) mutant to MTE cells was found to be reduced (by 50%) as compared with that of the wild type T lymphoma; (c) the Thy-1-mediated adhesion pathway did not require Ca2+ and promoted the initial thymo-epithelial binding measured at 4 degrees C. These data provide the first direct evidence of an adhesive function of Thy-1 and suggest that this molecule, in addition to its T cell triggering properties, might play a role during the early T cell maturation by promoting thymocyte adhesion to thymic stroma.
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Centre d'Immunologie INSERM-CNRS de Marseille Luminy, France.
Naquet
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Caillol
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Pierres
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D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000954:Antigens, Surface / Q000502:physiology*; D001667:Binding, Competitive / Q000276:immunology; D002118:Calcium / Q000378:metabolism*; D002448:Cell Adhesion / Q000502:physiology; D002452:Cell Count; D004847:Epithelial Cells; D051379:Mice; D051381:Rats; D013601:T-Lymphocytes / Q000166:cytology*; D018800:Thy-1 Antigens; D013950:Thymus Gland / Q000166:cytology*
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D018800:Thy-1 Antigens; D002118:Calcium