title: Ultrastructural evidence for association of vascular dendritic cells with T-lymphocytes and with B-cells in human atherosclerosis.
abstract: It has been previously demonstrated that dendritic cells are involved in human atherogenesis and immunohistochemical analysis indicated that S100+/CD1a+ vascular dendritic cells co-localize with lymphocytes in atherosclerotic lesions. Despite the high frequency of co-localization of vascular dendritic cells and lymphocytes in cell-rich areas, different type intimal cells were often intermingled and very closely apposed, which precluded determining whether vascular dendritic cells and lymphocytes specifically contacted each other or were simply densely packed together. Therefore, we undertook the present electronmicroscopical examination to see if vascular dendritic cells form direct contacts with lymphocytes in human atherosclerotic lesions. Serial sectioning of lymphocyte-rich areas of the human atherosclerotic aortas showed that vascular dendritic cells exhibiting a well developed tubulovesicular apparatus were located amongst T-lymphocytes and that through their processes, vascular dendritic cells formed multiple contacts with T-lymphocytes. In these contacts, vascular dendritic cell processes exhibited hypertrophied cisterns of the tubulovesicular system, which suggests the activation of vascular dendritic cells. From our observations we speculate that vascular dendritic cells may be responsible for the survival and activation of T-lymphocytes since a large number of T-lymphocytes which did not form contacts with vascular dendritic cells were found to have undergone destruction in atherosclerotic lesions. B-cells (plasma cells) were rarely seen in atherosclerotic lesions but vascular dendritic cells were found to form direct contacts with them. That vascular dendritic cells contact with both the T- and B-cells suggests that these vascular dendritic cells differ from other dendritic cells, subtypes of which are associated with T-cells (Langerhans cells, interdigitating cells) or with B-cells (follicular dendritic cells).
authors.affiliation: Department of Pathology, University of Tsukuba, Ibaraki, Japan.
authors.forename: Y V
authors.initials: YV
authors.lastname: Bobryshev
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001013:Aorta, Thoracic; D001161:Arteriosclerosis / Q000276:immunology / Q000473:pathology*; D001402:B-Lymphocytes / Q000473:pathology / Q000502:physiology / Q000648:ultrastructure*; D003713:Dendritic Cells / Q000473:pathology / Q000502:physiology / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D007365:Intercellular Junctions / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000473:pathology / Q000503:physiopathology / Q000648:ultrastructure*; D013601:T-Lymphocytes / Q000473:pathology / Q000502:physiology / Q000648:ultrastructure*