title: CD2 molecules redistribute to the uropod during T cell scanning: implications for cellular activation and immune surveillance.
abstract: Dynamic binding between CD2 and CD58 counter-receptors on opposing cells optimizes immune recognition through stabilization of cell-cell contact and juxtaposition of surface membranes at a distance suitable for T cell receptor-ligand interaction. Digitized time-lapse differential interference contrast and immunofluorescence microscopy on living cells now show that this binding also induces T cell polarization. Moreover, CD2 can facilitate motility of T cells along antigen-presenting cells via a movement referred to as scanning. Both activated CD4 and CD8 T cells are able to scan antigen-presenting cells surfaces in the absence of cognate antigen. Scanning is critically dependent on T cell beta-integrin function, as well as myosin light chain kinase. More importantly, surface CD2 molecules rapidly redistribute on interaction with a cellular substratum, resulting in a 100-fold greater CD2 density in the uropod versus the leading edge. In contrast, no redistribution is observed for CD11a/CD18 or CD45. Molecular compartmentalization of CD2, T cell receptor, and lipid rafts within the uropod prearranges the cellular activation machinery for subsequent immune recognition. This "presynapse" formation on primed T cells will likely facilitate the antigen-dependent recognition capability required for efficient immune surveillance.
authors.affiliation: Laboratory of Immunobiology, Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
authors.forename: Elena V
authors.initials: EV
authors.lastname: Tibaldi
authors.forename: Ravi
authors.initials: R
authors.lastname: Salgia
authors.forename: Ellis L
authors.initials: EL
authors.lastname: Reinherz
mesh_terms: D015703:Antigens, CD / Q000276:immunology; D018801:CD2 Antigens / Q000276:immunology*; D003593:Cytoplasm / Q000276:immunology; D006801:Humans; D007157:Immunologic Surveillance / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D018801:CD2 Antigens