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首页> 外文期刊>Infection and immunity >Inhibition of Human Peripheral Blood Mononuclear Cell Proliferation by Streptococcus pyogenes Cell Extract Is Associated with Arginine Deiminase Activity
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Inhibition of Human Peripheral Blood Mononuclear Cell Proliferation by Streptococcus pyogenes Cell Extract Is Associated with Arginine Deiminase Activity

机译:化脓性链球菌细胞提取物抑制人外周血单核细胞增殖与精氨酸脱亚氨酶活性有关

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Streptococcus pyogenes (group AStreptococcus) cell extracts (CE) have a remarkably powerful and dose-dependent inhibitory effect on antigen, superantigen, or mitogen-stimulated human peripheral blood mononuclear cell (PBMC) proliferation in vitro. Purification of the inhibitory component present in S. pyogenes type M5 (Manfredo strain) CE by anion-exchange chromatography followed by gel filtration chromatography showed that the inhibitor had an approximate native molecular mass of 100 kDa. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified inhibitory fractions followed by silver staining gave a single band with an approximate molecular mass of 47 kDa, indicating that the inhibitor is composed of two identical subunits. NH2-terminal sequencing of the protein revealed that it was identical to the previously characterized streptococcal acid glycoprotein (SAGP); this protein possesses between 31.5 and 39.0% amino acid identity with arginine deiminase (AD) from Mycoplasma hominis, Mycoplasma arginini, Pseudomonas putida, and Pseudomonas aeruginosa. AD enzyme activity was present in unfractionated CE prepared from a range of streptococcal strains, and partially purified inhibitory fractions of Manfredo CE also had high levels of activity. The inhibitory effect of Manfredo CE was overcome by the addition of l-arginine to proliferation assays in which human PBMC were stimulated with phytohemagglutinin. We conclude that SAGP, or its homolog, possesses AD activity and that the potent inhibition of proliferation of human T cells by streptococcal CE is due to activity of this enzyme.
机译:化脓性链球菌(A 链球菌组)细胞提取物对抗原,超抗原或有丝分裂原刺激的人外周血单核细胞具有显着的剂量依赖性抑制作用(PBMC)体外增殖。纯化存在于 S中的抑制性成分。阴离子交换色谱法和凝胶过滤色谱法测定化脓性M5型(曼弗雷多菌株)CE,结果表明该抑制剂的天然分子量约为100 kDa。纯化的抑制性部分的十二烷基硫酸钠-聚丙烯酰胺钠凝胶电泳,然后进行银染,得到一个单条带,分子量约为47 kDa,表明该抑制剂由两个相同的亚基组成。该蛋白的NH 2 末端测序表明,该蛋白与先前鉴定的链球菌酸性糖蛋白(SAGP)相同。该蛋白与来自人支原体支原体支原体恶臭假单胞菌和< em>铜绿假单胞菌。 AD酶活性存在于由一系列链球菌菌株制备的未分级分离的CE中,Manfredo CE的部分纯化的抑制级分也具有高水平的活性。 Manfredo CE的抑制作用通过在增殖测定中添加了l-精氨酸而得以克服,在该测定中,植物血凝素刺激了人PBMC。我们得出的结论是SAGP或其同源物具有AD活性,并且链球菌CE对人T细胞增殖的有效抑制是由于该酶的活性。

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