van den Berg C W, Aerts P C, van Dijk H
Eijkman-Winkler Laboratory of Medical Microbiology, Department of Experimental Microbiology, Faculty of Medicine, University of Utrecht, The Netherlands.
Mol Immunol. 1992 Mar;29(3):363-9. doi: 10.1016/0161-5890(92)90023-q.
Fractionation of mouse serum by precipitation with a critical amount of polyethylene glycol 6000 (PEG; 11% w/v) results in a classical and alternative pathway-independent activation of the terminal complement route. The activation can take place after the separation of an activating principle together with the terminal route components from a natural regulator. The isolation and identification of the regulatory component preventing this activation in serum, is subject of this paper. The regulator was purified by fractionated PEG-precipitation (15-25%), followed by heparin-Sepharose affinity, Mono Q anion-exchange, and Superose 12 gel filtration chromatography. The regulator appeared to be a single-chain protein with a Mr of 96 k. A protein with similar activity purified from human serum had a Mr of 104 k and was functionally and antigenically indistinguishable from C1-INH. The mouse 96 k protein inhibited C1-esterase activity indicating that this protein is indeed C1-INH. Mouse C1-INH regulates the PEG fractionation-induced bypass activation of complement, but does not interfere with the assembly or the lytic activity of membrane attack complexes. alpha 2-Macroglobulin appeared also to be capable of inhibiting the PEG-precipitation-induced activation process, but with lower efficiency.
用临界量的聚乙二醇6000（PEG；11% w/v）沉淀法对小鼠血清进行分级分离，可导致终末补体途径的经典途径和替代途径非依赖性激活。在将激活因子与终末途径成分从天然调节因子中分离后，激活即可发生。本文的主题是血清中阻止这种激活的调节成分的分离和鉴定。通过分级PEG沉淀（15 - 25%），随后进行肝素-琼脂糖亲和层析、Mono Q阴离子交换层析和Superose 12凝胶过滤层析来纯化调节因子。该调节因子似乎是一种Mr为96 k的单链蛋白。从人血清中纯化的具有类似活性的蛋白Mr为104 k，在功能和抗原性上与C1抑制物（C1-INH）无法区分。小鼠96 k蛋白抑制C1酯酶活性，表明该蛋白确实是C1-INH。小鼠C1-INH调节PEG分级分离诱导的补体旁路激活，但不干扰膜攻击复合物的组装或溶解活性。α2-巨球蛋白似乎也能够抑制PEG沉淀诱导的激活过程，但效率较低。
