title: CD28 costimulatory molecule--expression, structure and function.
abstract: T cell activation is a key event in triggering an antigen specific immune response of the organism. The process is induced primarily by the signal generated by direct interaction of a T cell receptor with an antigen bound to the major histocompatibile complex on an antigen-presenting cell (APC). Although the signal is critical in exciting immune response, an additional, costimulating signal is required. The major second signal is generated by interaction of the CD28 molecule expressed on most T lymphocytes with its natural ligands CD80 and CD86 located on APCs. The signal excited by CD28 triggering involves multiple second-messenger cascades, leading to the activation of transcription factors and finally results in cell proliferation, cytokine production, and the generation of effector functions. The importance of CD28-delivered costimulatory signals was proven in experiments with CD28-deficient mice. T cells from these mice exhibited an impaired pattern of cytokine secretion and defects in T cell-dependent antibody production. Certain forms of immunopathology might result from the aberrant regulation of CD28 expression.
authors.affiliation: Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114 Wrocław, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Boćko
authors.forename: Agata
authors.initials: A
authors.lastname: Kosmaczewska
authors.forename: Lidia
authors.initials: L
authors.lastname: Ciszak
authors.forename: Renata
authors.initials: R
authors.lastname: Teodorowska
authors.forename: Irena
authors.initials: I
authors.lastname: Frydecka
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D015703:Antigens, CD / Q000502:physiology; D018122:B7-1 Antigen / Q000502:physiology; D051940:B7-2 Antigen; D018106:CD28 Antigens / Q000032:analysis / Q000737:chemistry / Q000502:physiology*; D016207:Cytokines / Q000096:biosynthesis; D051380:GRB2 Adaptor Protein; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000502:physiology; D015513:Oncogene Proteins / Q000502:physiology; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D051966:Phospholipase C gamma; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D011506:Proteins / Q000502:physiology; D051567:Proto-Oncogene Proteins c-vav; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018106:CD28 Antigens; C497964:CD86 protein, human; D016207:Cytokines; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D007527:Isoenzymes; D008562:Membrane Glycoproteins; D015513:Oncogene Proteins; D011506:Proteins; D051567:Proto-Oncogene Proteins c-vav; C496618:VAV1 protein, human; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; C080813:emt protein-tyrosine kinase; D010738:Type C Phospholipases; D051966:Phospholipase C gamma