title: Differences in signaling molecule organization between naive and memory CD4+ T lymphocytes.
abstract: The immunological synapse is a highly organized complex formed at the junction between Ag-specific T cells and APCs as a prelude to cell activation. Although its exact role in modulating T cell signaling is unknown, it is commonly believed that the immunological synapse is the site of cross-talk between the T cell and APC (or target). We have examined the synapses formed by naive and memory CD4 cells during Ag-specific cognate interactions with APCs. We show that the mature immunological synapse forms more quickly during memory T cell activation. We further show that the composition of the synapse found in naive or memory cell conjugates with APCs is distinct with the tyrosine phosphatase, CD45, being a more integral component of the mature synapses formed by memory cells. Finally, we show that signaling molecules, including CD45, are preassociated in discrete, lipid-raft microdomains in resting memory cells but not in naive cells. Thus, enhanced memory cell responses may be due to intrinsic properties of signaling molecule organization.
authors.affiliation: Department of Biomedical Sciences, School of Public Health, State University of New York, Albany, NY 12201-0509, USA.
authors.forename: Andrew R O
authors.initials: AR
authors.lastname: Watson
authors.forename: William T
authors.initials: WT
authors.lastname: Lee
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000502:physiology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000502:physiology; D005260:Female; D007156:Immunologic Memory; D017493:Leukocyte Common Antigens / Q000032:analysis; D008297:Male; D021962:Membrane Microdomains / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D015398:Signal Transduction; D013569:Synapses / Q000502:physiology; D051746:ZAP-70 Protein-Tyrosine Kinase
chemical_list: D011948:Receptors, Antigen, T-Cell; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C497262:Zap70 protein, mouse; D017493:Leukocyte Common Antigens