Interleukin-12: an immunoregulatory cytokine produced by B cells and antigen-presenting cells.
Interleukin 12 (IL-12) is a heterodimeric protein produced by B cells, phagocytic cells, and other antigen-presenting cells. IL-12 was originally purified from the supernatant fluids of human EBV-transformed cell lines and later observed to be produced by the large majority of such cell lines, especially and at high levels from those derived from AIDS-associated lymphomas. However, phagocytic cells rather than B cells appear to be the most important physiological producers of IL-12. There are two pathways of IL-12 induction in phagocytic cells: a T-cell-independent one, induced primarily by bacteria, bacterial products, or intracellular parasites and important in the early inflammatory response of innate resistance; and a T-cell-dependent one, induced by the interaction of CD40L on activated T cells with CD40 receptor on IL-12-producing cells (phagocytic cells and antigen-presenting cells) and important in the regulation of adaptive immunity. IL-12 induces production of cytokines, especially interferon-gamma, from both T and NK cells, enhances the cytotoxic activity of NK cells and the generation of cytotoxic T cells, and has a proliferative activity on T and NK cells. Both in vivo and in vitro, IL-12 is a powerful inducer of T helper type 1 (Th1) response, whereas it inhibits Th2-type responses.
Sartori
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The Wistar Institute of Anatomy and Biology, Philadelphia, Pennsylvania 19104, USA.
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Showe
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Benjamin
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Trinchieri
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D000938:Antigen-Presenting Cells / Q000276:immunology / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D019013:CD40 Antigens / Q000378:metabolism; D002460:Cell Line; D005786:Gene Expression Regulation / Q000235:genetics*; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects / Q000276:immunology; D007371:Interferon-gamma / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism* / Q000494:pharmacology / Q000627:therapeutic use; D010703:Phorbol Esters / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects; D014170:Transformation, Genetic / Q000235:genetics
D019013:CD40 Antigens; D010703:Phorbol Esters; D018664:Interleukin-12; D007371:Interferon-gamma