Studies on the mechanisms of C9 activation and of C9 inactivation by the regulatory protein(MACIF)

调节蛋白(MACIF)激活C9和失活C9机制的研究

• 批准号: 03671118
• 负责人: HATANAKA Michiyo
• 金额: $ 1.34万
• 依托单位: Osaka Medical College
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03671118/
• 关键词: Complement; C9; Monoclonal antibodies; DTT; GPI-anchor; PNH; DAF; MACIF(CD59); モノクロ-ナル抗体; 合成ペプチド; DTT; ジスルフィド結合

The complement system consist of more than 20 serum proteins and play an important role in host defense. Complement component C9 exerts at the final step of complement cascade by inserting into membranes which contain preformed C9 acceptor, C5b-8. C9 proceeds drastic conformational changes upon interaction with C5b-8 complex. Although the entire primary structure has already been demonstrated, the structual and function relationship is not fully ubderstood. In this research, we intended to clarify the mechanisms of C9 activation by using monoclonal antibodies to C9 and also with chemical modification reagent, DTT. It has been demonstrated that1. Two seperate epoitipes of C9 are involved in C5b-8 binding.2. Functional domains of C9 are supported by disulfide bridges.3. Different and distinct domains of disulfide bridges are implicated in binding to C5b-8, hemolytic activity, and self-polymerization of C9.Complement functions are targeted only on non-self membranes, and activation does not occur on self membranes. Complement regulating proteins (DAF, MACIF, MCP, CR1) have now been demonstrated to play the crucial roles in self- and non-self determination. We have assesed the function of DAF and MACIF by inccorporating the isolated proteins to PNH erythrocytes which deffect these proteins.

补体系统由20多种血清蛋白组成，在宿主防御中起重要作用。补体成分C9通过插入含有预先形成的C9受体C5 b-8的膜中，在补体级联的最后一步发挥作用。C9在与C5 b-8复合物相互作用时发生了剧烈的构象变化。虽然整个一级结构已经被展示出来，但结构和功能之间的关系还没有被完全理解。在本研究中，我们打算通过使用C9的单克隆抗体和化学修饰试剂DTT来阐明C9活化的机制。已经证明，1。C9的两个独立的表位参与C5 b-8的结合. C9的功能结构域由二硫桥支持。二硫键的不同结构域与C5 b-8的结合、溶血活性和C9的自聚合有关。补体功能仅靶向于非自身膜，而激活不发生在自身膜上。补体调节蛋白（CR 1，MACIF，MCP，CR 1）在自我决定和非自我决定中起着重要作用。我们通过将分离的蛋白质掺入PNH红细胞中，以检测这些蛋白质的作用，来评估MACIF和MACIF的功能。

项目成果

宮川 周士: "Test for ability of decay-accelerating factor(DAF,CD55)and CD59 to alleviate complement-mediated damage of xeno-erythrocytes" Scandinavian Journal of Immunology.

Shuji Miyakawa：“测试衰变加速因子（DAF、CD55）和 CD59 减轻补体介导的异种红细胞损伤的能力”斯堪的纳维亚免疫学杂志。

Michiyo Hatanaka: "Analysis of C5b-8 bindig sites in C9 molecules using monoclonal antibodies : participation of two seperate epitopes of C9 in C5b-8 binding" Molecular Immunology. 29. 911-916 (1992)

Michiyo Hatanaka：“使用单克隆抗体分析 C9 分子中的 C5b-8 结合位点：C9 的两个单独表位参与 C5b-8 结合”分子免疫学。