The role of B7 costimulation in T-cell immunity.
CD4+ T cells are considered to be the major controlling element of the adaptive immune response. They recognize foreign peptides by interaction of the T cell receptor (TCR) with peptide complexed to major histocompatibility complex (MHC) class II molecules on the surface of antigen presenting cells (APC). Once activated, CD4+ T cells orchestrate the various phases of the immune response. They are responsible for the production of numerous cytokines, which activate specific immune effector cell populations including B cells, eosinophils, mast cells and macrophages. Not surprisingly, the activation of CD4+ T cells needs to be tightly regulated and is subject to finely tuned control mechanisms. The requirement for a second or 'costimulatory' signal, in addition to the antigenic signal, provides a key element for the exquisite control of T cell activation. One of the major signalling pathways responsible for delivery of this costimulatory signal is induced by interaction of CD28 on T cells with B7 molecules found only on APC. The present review outlines our current understanding of the physiological role of B7 costimulatory signals in regulating CD4+ T cell responses.
Harris
N L
NL
Malaghan Institute of Medical Research, Wellington School of Medicine, Wellington South, New Zealand. nicola@wnmeds.ac.nz
Ronchese
F
F
D000069594:Abatacept; D000818:Animals; D000917:Antibody Formation; D015703:Antigens, CD / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000943:Antigens, Differentiation / Q000378:metabolism; D018122:B7-1 Antigen / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051940:B7-2 Antigen; D018106:CD28 Antigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D060908:CTLA-4 Antigen; D006801:Humans; D018796:Immunoconjugates; D007156:Immunologic Memory; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D013601:T-Lymphocytes / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology
D015703:Antigens, CD; D000943:Antigens, Differentiation; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018106:CD28 Antigens; C497964:CD86 protein, human; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; C497965:Cd86 protein, mouse; C556707:Ctla4 protein, mouse; D018796:Immunoconjugates; D008562:Membrane Glycoproteins; D000069594:Abatacept