title: Stimulation of naïve T-cell adhesion and immunological synapse formation by chemokine-dependent and -independent mechanisms.
abstract: Chemokines adsorbed to the cell surface play an important role in the initial interactions of T cells with endothelial cells, and may also have a role in T-cell interactions with dendritic cells. Therefore, we examined the effect of surface-adsorbed chemokines on the interaction of naïve murine splenic T cells with supported bilayers containing intercellular adhesion molecule (ICAM)-1, or with bone marrow-derived cultured dendritic cells in the presence and absence of relevant MHC-peptide complexes. Naïve T cells formed immunological synapses, defined as a ring of lymphocyte function associated (LFA)-1-ICAM-1 interactions surrounding a central cluster of MHC-peptide complexes, on supported planar bilayers containing ICAM-1 and relevant MHC-peptide complexes. Chemokines stimulated an increase in the percentage of naïve cells that adhered to ICAM-1, but did not increase the average number of LFA-1-ICAM-1 interactions in the contact area. In contrast, relevant MHC-peptide complexes resulted in a small increase in the proportion of interacting T cells, but stimulated an 8-fold increase in the number of LFA-1-ICAM-1 interactions in each contact formed. Naïve T cells displayed a significant basal adhesion to bone marrow dendritic cells that was further increased when relevant chemokines were adsorbed to the dendritic cell surface. However, basal and antigen-stimulated T-cell adhesion to dendritic cells was not sensitive to pertussis toxin. Thus, there are chemokine-independent mechanisms that initiate adhesion between T cells and dendritic cells.
authors.affiliation: Graduate Program in Immunology, Washington University School of Medicine, St. Louis, MO, USA.
authors.forename: Shannon K
authors.initials: SK
authors.lastname: Bromley
authors.forename: Michael L
authors.initials: ML
authors.lastname: Dustin
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000276:immunology; D002450:Cell Communication / Q000276:immunology; D002478:Cells, Cultured; D018925:Chemokines / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology*; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D016169:Lymphocyte Function-Associated Antigen-1 / Q000276:immunology; D051379:Mice; D008822:Mice, Transgenic; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D018925:Chemokines; D016169:Lymphocyte Function-Associated Antigen-1; D018799:Intercellular Adhesion Molecule-1