title: The mechanism of antigen presentation by endothelial cells.
abstract: Endothelial cells line the vessels and lymphatics forming a barrier between circulating T cells and the extravascular tissue site of antigen. We have suggested that circulating T cells recognize antigen on the surface of endothelial cells, resulting in the activation of the endothelium such that the endothelial cells then release the key mediators of a cell-mediated immune response. To test this hypothesis, we have evaluated the extent to which endothelial cells can signal antigen-specific T cell activation. We have shown that cultured endothelial cells are as effective as macrophages in lymphocyte activation and that this activation is HLA-DR restricted. In additional experiments we have established that endothelial cells synthesize both Ia and IL-1 early in the signaling process. To eliminate any possible contribution of other cell types participating in the T cell-endothelial cell interaction, we have shown that cloned endothelial cells present antigen to cloned T cells. Moreover, there appeared to be a preference of selected T-cell populations for different types of antigen presenting cells. These experiments document that endothelial cells are independently competent antigen presenting cells.
mesh_terms: D000938:Antigen-Presenting Cells / Q000276:immunology*; D001808:Blood Vessels / Q000276:immunology*; D002478:Cells, Cultured; D004727:Endothelium / Q000276:immunology; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D006801:Humans; D007111:Immunity, Cellular; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000096:biosynthesis; D008208:Lymphatic System / Q000276:immunology*; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D007375:Interleukin-1