Isolation and characterization of a novel liver-derived immunoinhibitory factor.
Isolation and characterization of a novel liver-derived immunoinhibitory factor.
复制标题
新型肝源性免疫抑制因子的分离和表征。
DOI：
10.1002/hep.1840140522
复制
发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Cohen,SA
中科院分区：
文献类型：
--
作者：
Tzung,SP;Gaines,KC;Henderson,M;Smith,TJ;Cohen,SA
从C57 BL/6小鼠灌流的全肝或纯化的肝细胞制备的胞质提取物在体外抑制白细胞介素-2和刀豆球蛋白A诱导的脾细胞增殖。相反，从纯化的非实质肝细胞胞质提取物没有影响。精氨酸酶和极低密度脂蛋白先前被鉴定为存在于肝细胞溶质提取物中的两种免疫抑制物质。然而，我们证明，在分别通过重复超离心和凝胶过滤色谱法从肝胞质提取物中去除极低密度脂蛋白和胆固醇酯酶后，抑制活性仍然存在，表明存在另一种抑制剂。通过阴离子交换色谱和色谱聚焦进一步纯化，分离出一种新的肝源性免疫抑制因子。这种肝源性免疫抑制因子对链霉蛋白酶消化、热和酸处理敏感;估计等电点为8.25。根据十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上的迁移估计，Mrof肝源性免疫抑制因子为28 kD，在还原和非还原条件下均相同，表明该蛋白质为单体性质。氨基酸组成分析揭示肝源性免疫抑制因子相对富含甘氨酸和脯氨酸残基。该肝源性免疫抑制因子可抑制白细胞介素2诱导的体外脾细胞增殖，50%抑制剂量为1.4 nmol/L。此外，肝源性免疫抑制因子的生物活性并不局限于小鼠脾细胞，因为B16小鼠黑色素瘤和H35大鼠肝癌细胞的生长也受到抑制。与先前报道的其他肝源性免疫抑制剂的比较支持我们的主张，即肝源性免疫抑制因子是一种新型抑制蛋白。（Hepatology1991;14：888-894）。
Cytosolic extracts prepared from perfused whole liver or purified hepatocytes of C57BL/6 mice inhibited interleukin‐2– and concanavalin A–induced spleen cell proliferationin vitro. In contrast, cytosolic extracts from purified nonparenchymal liver cells had no effect. Arginase and very‐low‐density lipoprotein were previously identified as two immunoinhibitory substances present in liver cytosolic extracts. We demonstrated, however, that inhibitory activity remained after removal of very‐low‐density lipoprotein and arginase from liver cytosolic extract by repeated ultracentrifugation and gel filtration chromatography, respectively, suggesting the presence of another inhibitor. Further purification by anion‐exchange chromatography and chromatofocusing led to the isolation of a novel liverderived immunoinhibitory factor. This liver‐derived immunoinhibitory factor is sensitive to pronase digestion and heat and acid treatment; it has an estimated isoelectric point of 8.25. The Mrof liver‐derived immunoinhibitory factor is 28 kD as estimated from its migration on sodium dodecyl sulfate–polyacrylamide gel electrophoresis, which is identical under both reducing and nonreducing conditions, indicating a monomeric nature of this protein. Amino acid composition analysis discloses that liver‐derived immunoinhibitory factor is relatively rich in glycine and proline residues. Interleukin‐2–induced spleen cell proliferationin vitrois inhibited by this liver‐derived immunoinhibitory factor, with a 50% inhibitory dose of 1.4 nmol/L. Furthermore, the biological activity of the liver‐derived immunoinhibitory factor is not confined to mouse spleen cells, since the growth of B16 mouse melanoma and H35 rat hepatoma cells is also inhibited. A comparison with other liver‐derived immunoinhibitors reported previously supports our claim that the liver‐derived immunoinhibitory factor is a novel inhibitory protein. (HEPATOLOGY1991;14:888–894).