Immunology. The immunological synapse – a multitasking system
van Der Merwe PA, Davis SJ. (2002), Science. 295, 1479-80
Key figure: The center of attention
(Top) The organization of the immunological synapse formed at the interface between an antigen-presenting cell (APC) and a responding T cell. The central zone of this structure, from which large adhesion molecules such as the integrin LFA-1 (blue) are excluded, contains T cell receptors (TCRs; pink), CD28 costimulatory receptors (yellow), and other smaller molecules (5). (A) Engagement of the TCR with peptide-MHC on the APC surface results in peptide-MHC signaling within the APC. Interaction of the costimulatory receptor CD28 with its ligands, which results in secondary signaling, is enhanced in the central region of the immunological synapse. (B) Key effector molecules, such as the cytokine IL-4 and the inhibitory protein CTLA-4, delivered to the central area by exocytosis, limit effects on bystander cells. (C) The immunological synapse may be required for internalization of TCRs, which may be one way that TCR signaling is down-regulated.