Cutting edge: Complement-activating complex of ficolin and mannose-binding lectin-associated serine protease
Cutting edge: Complement-activating complex of ficolin and mannose-binding lectin-associated serine protease
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DOI：
10.4049/jimmunol.164.5.2281
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发表时间：
2000-03-01
影响因子：
4.4
通讯作者：
Fujita, T
中科院分区：
文献类型：
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作者：
Matsushita, M;Endo, Y;Fujita, T
纤维胶凝蛋白和甘露糖结合凝集素（MBL）都是凝集素，其特征在于在亚基中存在胶原样结构域和碳水化合物结合结构域，尽管它们的碳水化合物结合部分非常不同。纤维蛋白原样结构域在纤维胶凝蛋白中，碳水化合物识别结构域在MBL中。在与病原体结合时，人MBL通过凝集素途径与两种类型的MBL相关丝氨酸蛋白酶（MASP）MASP-1和MASP-2及其截短形式小MBL相关蛋白（sMAP，也称为MAp 19）结合激活补体系统。我们在这里报告，纤维胶凝蛋白/P35，人血清纤维胶凝蛋白，被发现与MASPs和sMAP共纯化。与纤维胶凝蛋白/P35复合的MASP表现出针对补体组分C4、C2和C3的蛋白水解活性。与鼠伤寒沙门氏菌结合的纤维胶凝蛋白/P35-MASPs-sMAP复合物激活补体。这些发现表明纤维胶凝蛋白/P35是能够激活凝集素途径的第二种胶原凝集素，因此在先天免疫中起作用。
Both ficolins and mannose-binding lectin (MBL) are lectins characterized by the presence of collagen-like and carbohydrate-binding domains in a subunit, although their carbohydrate-binding moieties are quite different. A fibrinogen-like domain is in ficolins, and a carbohydrate recognition domain is in MBL. On binding to pathogens, human MBL activates the complement system via the lectin pathway in association with two types of MBL-associated serine proteases (MASP), MASP-1 and MASP-2 and its truncated form, small MBL-associated protein (sMAP, also called MAp19). We report here that ficolin/P35, a human serum ficolin, was found to copurify with MASPs and sMAP. MASPs that were complexed with ficolin/P35 exhibited proteolytic activities against complement components C4, C2, and C3. The ficolin/P35-MASPs-sMAP complex that was bound to Salmonella typhimurium activated complement. These findings indicate that ficolin/P35 is a second collagenous lectin capable of activating the lectin pathway and thus plays a role in innate immunity.