Studies on a nocal sevine protease and the activation mechanism of the lectin complement pathway

甘露糖结合凝集素（MBL）和L-ficolin/P35是与MASP络合的人血清凝集素。当这些复合物与微生物表面的碳水化合物结合时，MASP切割C2、C3和C4，从而激活补体系统（凝集素途径）。目前已经确定了三种类型的MASP （MASP-1、-2和-3）。sMAP是MASP-2的一个剪接变体，也与MBL和L-ficolin/P35相关。MBL主要形成三种不同大小的低聚物。复合物中MASPs的组成因低聚物而异。在这个研究项目中，我们获得了以下主要结果。我们成功地从复合物中分离出L-ficolin/P35和MASPs/sMAP。L-ficolin/P35与MASPs和sMAP结合，其解离常数与MBL与MASPs/sMAP相互作用的解离常数相似。我们建立了一种分离masp -1和MASP-3.3的方法。博多抗原激活与MASPs和smap相关的凝集素途径。MASP-1具有切割凝血系统因子IX的能力，而MASP-2和MASP-3分别具有低活性和无活性。T98G细胞是人胶质瘤细胞系，可产生博多抗原、MASP-1和MASP-3。

Mannose-binding lectin (MBL) and L-ficolin/P35 are human serum lections that are complexed with MASP. Upon binding of these complexes to carbohydrates on the surfaces of microbes, MASP cleaves C2,C3 and C4 resulting in activation of the complement system (lectin pathway). Three types of MASP (MASP-1, -2 and -3) have been identified so far. sMAP, a splicing variant of MASP-2, is also associated with MBL and L-ficolin/P35. MBL forms mainly three types of oligomer with different sizes. The Composition of MASPs in the complex varies from oligomer to oligomer. In this research project we obtained the following main results.1. We succeeded in the separation of L-ficolin/P35 and MASPs/sMAP from the complex. L-ficolin/P35 binds to MASPs and sMAP with similar dissociation constants to those for the interaction between MBL and MASPs/sMAP.2. We developed a method for the separation ofMASP-1 and MASP-3.3. Hakata antigen activates the lectin pathway in association with MASPs and sMAP.4. MASP-1 has a ability to cleave the factor IX of the clotting system, while MASP-2 and MASP-3 have low and no activities, respectively.5. T98G cells, a cell line of human glioma, produce Hakata antigen, MASP-1 and MASP-3.