Sartori A, Ma X, Gri G, Showe L, Benjamin D, Trinchieri G
The Wistar Institute of Anatomy and Biology, Philadelphia, Pennsylvania 19104, USA.
Methods. 1997 Jan;11(1):116-27. doi: 10.1006/meth.1996.0395.
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.
白细胞介素12（IL-12）是一种由B细胞、吞噬细胞和其他抗原呈递细胞产生的异源二聚体蛋白。IL-12最初是从人EB病毒转化细胞系的上清液中纯化出来的，后来发现大多数此类细胞系都能产生IL-12，尤其是来自艾滋病相关淋巴瘤的细胞系，其产生水平很高。然而，吞噬细胞而非B细胞似乎是IL-12最重要的生理产生者。吞噬细胞中IL-12的诱导有两条途径：一条是不依赖T细胞的途径，主要由细菌、细菌产物或细胞内寄生虫诱导，在先天抵抗力的早期炎症反应中起重要作用；另一条是依赖T细胞的途径，由活化T细胞上的CD40L与产生IL-12的细胞（吞噬细胞和抗原呈递细胞）上的CD40受体相互作用诱导，在适应性免疫调节中起重要作用。IL-12可诱导T细胞和NK细胞产生细胞因子，尤其是干扰素-γ，增强NK细胞的细胞毒性活性和细胞毒性T细胞的生成，并对T细胞和NK细胞具有增殖活性。在体内和体外，IL-12都是1型辅助性T细胞（Th1）反应的强大诱导剂，而它会抑制Th2型反应。
