title: Syn-capping of human T lymphocyte adhesion/activation molecules and their redistribution during interaction with endothelial cells.
abstract: Lymphocyte-endothelial cell interactions are mediated in part by multiple lymphocyte surface adhesion/activation molecules and their cognate ligands. We investigated the surface localization of several of these molecules implicated in T cell adhesion and transendothelial migration mechanisms to determine if spatial regulation of their distribution contributes to these processes. T lymphocyte suspensions were stained to define distribution, ability to be aggregated into energy-dependent caps, and potential cocapping of several adhesion structures. CD2, CD44, L-selectin (LAM-1, LECCAM-1), and CD11a/CD18 (LFA-1) exhibited uniform distribution on the T cell surface by direct immunofluorescence but formed caps in an energy-dependent, and therefore cytoskeletally driven, manner when examined by indirect immunofluorescence. CD2 was shown to syn-cap (unidirectionally cocap) with CD44 and CD11a/CD18 (LFA-1), an observation potentially related to functional cooperation among these molecules in T cell activation. T cells were also added to endothelial cell monolayers to assess, in a physiologically relevant context, potential surface molecule reorganization. Lymphocytes co-cultured with human umbilical vein endothelial cells (HUVEC) underwent a profound shape change, from essentially round cells to polarized cells bearing pseudopodia. Immunofluorescent localization of T cell adhesion/activation molecules using confocal microscopy revealed the redistribution of CD2, CD44, and L-selectin to the pseudopod. In contrast, CD11a/CD18 remained globally distributed on the cell surface, even in severely deformed cells. Both lymphocyte shape change and membrane molecule redistribution appear to be cell-cell contact-dependent phenomena requiring intact, viable endothelial cells. Mechanisms that control these events may be critical to lymphocyte recirculation and inflammation.
authors.affiliation: ICOS Corporation, Bothell, Washington 98021.
authors.forename: S J
authors.initials: SJ
authors.lastname: Rosenman
authors.forename: A A
authors.initials: AA
authors.lastname: Ganji
authors.forename: T F
authors.initials: TF
authors.lastname: Tedder
authors.forename: W M
authors.initials: WM
authors.lastname: Gallatin
mesh_terms: D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000032:analysis / Q000502:physiology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis / Q000502:physiology; D018845:CD11 Antigens; D018821:CD18 Antigens; D018801:CD2 Antigens; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000502:physiology*; D002462:Cell Membrane / Q000276:immunology; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000276:immunology / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D019041:L-Selectin; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1 / Q000032:analysis / Q000502:physiology; D011971:Receptors, Immunologic / Q000032:analysis / Q000502:physiology; D016201:Receptors, Lymphocyte Homing / Q000032:analysis / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology*; D014471:Umbilical Veins
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D018845:CD11 Antigens; D018821:CD18 Antigens; D018801:CD2 Antigens; D015815:Cell Adhesion Molecules; D016169:Lymphocyte Function-Associated Antigen-1; D011971:Receptors, Immunologic; D016201:Receptors, Lymphocyte Homing; D019041:L-Selectin