title: Co-stimulation and co-inhibition: equal partners in regulation.
abstract: Specific immune responses are controlled by two counterbalancing mechanisms-co-stimulation and co-inhibition. Antigen receptors determine specificity, activate co-stimulation and/or co-inhibition, and interact with these co-stimulatory/co-inhibitory mechanisms to dictate the direction of the immune response, either positive or negative. Co-stimulatory or co-inhibitory ligands interact with their specific receptors and may indicate the context in which antigen is perceived by lymphocytes. Ligation of antigen receptors may activate only co-stimulatory or co-inhibitory mechanisms, and thus may influence secondarily the direction of the immune response. Furthermore, the activity of a given co-stimulator or co-inhibitory receptor is modified depending on signalling via the antigen receptor. If neither co-stimulators nor co-inhibitors are present, lymphocytes, activated in response to antigen receptor signalling, produce low levels of effector elements and then revert to inactivity. Co-inhibitors are defective in autoimmune disease.
authors.affiliation: Department of Microbiology and Immunology, University of Western Ontario, London, Canada.
authors.forename: N R
authors.initials: NR
authors.lastname: Sinclair
authors.forename: C C
authors.initials: CC
authors.lastname: Anderson
mesh_terms: D000818:Animals; D017209:Apoptosis; D001327:Autoimmune Diseases / Q000276:immunology; D006801:Humans; D007108:Immune Tolerance; D007109:Immunity; D008214:Lymphocytes / Q000502:physiology*; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D011947:Receptors, Antigen, B-Cell; D011948:Receptors, Antigen, T-Cell