The role of B7 costimulation in T-cell immunity

• Published in: Immunology and cell biology Vol. 77; no. 4; p. 304
• Main Authors: Harris, N L, Ronchese, F
• Format: Journal Article
• Language: English
• Published: United States 01.08.1999
• Subjects: Abatacept; Animals; Antibody Formation; Antigens, CD - chemistry; Antigens, CD - genetics; Antigens, CD - metabolism; Antigens, Differentiation - metabolism; B7-1 Antigen - chemistry; B7-1 Antigen - genetics; B7-1 Antigen - metabolism; B7-2 Antigen; CD28 Antigens - chemistry; CD28 Antigens - genetics; CD28 Antigens - metabolism; CTLA-4 Antigen; Humans; Immunoconjugates; Immunologic Memory; Lymphocyte Activation; Membrane Glycoproteins - chemistry; Membrane Glycoproteins - genetics; Membrane Glycoproteins - metabolism; Mice; Models, Biological; T-Lymphocytes - immunology; Th1 Cells - immunology; Th2 Cells - immunology
• ISSN: 0818-9641
• DOI: 10.1046/j.1440-1711.1999.00835.x

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.