title: Migrating lymph dendritic cells contain intracellular CD40 that is mobilized to the immunological synapse during interactions with antigen-specific T lymphocytes.
abstract: Steady state migrating rat lymph dendritic cells (LDC) are semimature, expressing high levels of surface MHC class II, but low levels of surface costimulatory molecules. In this study, we show that surface CD40 is not detectable, but LDC contain intracellular CD40. Multiple isoforms of CD40 were detected, including the type 1 isoform required for signal transduction. Culture of LDC with syngeneic T cells does not induce redistribution of cytoplasmic CD40. When LDC were cultured with naive allogeneic CD4(+) T lymphocytes, polarization of CD40 to the immune synapse occurred between 3 and 6 h postculture. By 24 h, although large numbers of T cells were engaged with LDC, CD40 could not be detected in LDC or at the synapses. We conclude that migrating LDC contain stores of CD40 that can be mobilized rapidly to the sites of interaction with Ag-specific T cells. The disappearance of CD40 by 24 h may help in the regulation of T cell activation.
authors.affiliation: School of Veterinary Science and Medicine, University of Nottingham, Leicestershire NG7 2NR, United Kingdom. n.foster@nottingham.ac.uk
authors.forename: Neil
authors.initials: N
authors.lastname: Foster
authors.forename: Emma L
authors.initials: EL
authors.lastname: Turnbull
authors.forename: Gordon
authors.initials: G
authors.lastname: Macpherson
mesh_terms: D000818:Animals; D019013:CD40 Antigens / Q000276:immunology / Q000378:metabolism*; D002450:Cell Communication / Q000276:immunology*; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000276:immunology*; D016764:Cell Polarity / Q000276:immunology; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D054992:Immunological Synapses / Q000378:metabolism*; D007424:Intracellular Fluid / Q000276:immunology / Q000378:metabolism; D008196:Lymph / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000378:metabolism
chemical_list: D019013:CD40 Antigens; D018984:Epitopes, T-Lymphocyte; D020033:Protein Isoforms