Product Description

C1s depleted serum (C1s-Dpl) is normal human serum depleted of C1s byimmunoaffinity chromatography. The product is tested for the absence ofC1s by functional assays for classical pathway activity and for C1sprotein by double immunodiffusion. C1s-Dpl is certified to possess afunctional alternative pathway for complement activation (Morgan, B.P.(2000); Dodds, A.W. and Sim, R.B. (1997)).

In serumC1s is present in its proenzyme form (Valet, G and Cooper N.R. (1974);Ziccardi, R.J. and Cooper N.R. (1976)). C1s enzyme is the activated formof C1s proenzyme. C1s is a subunit of the C1 complex which is the firstcomponent in the classical pathway of complement (See productdescription for C1 Cat# A098). C1s proenzyme is an inactive zymogenuntil C1 is activated. C1r is activated when C1 binds to and isactivated by antibodies bound to antigens (immune complexes) yieldingC1r enzyme, the first protease that initiates the cascade. C1r enzyme inthe C1 complex activates C1s proenzyme generating C1s enzyme. Afunctional classical pathway can be reconstituted by addition ofpurified C1s proenzyme (31 µg/mL) to the C1s-Dpl indicating that allother complement components necessary for classical pathway activationare present and active.

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Complement Technology的C1是级联反应中的第一个补体成分，称为补体经典途径。C1与抗原结合的抗体（免疫复合物）结合并被其激活，从而产生引发级联反应的蛋白酶。C1实际上是钙依赖性复合物中结合在一起的三种不同蛋白质（C1q，C1r和C1s）的非共价复合物。C1q通过其六个臂中的两个或多个与IgG或IgM的Fc结构域结合。多臂与免疫复合物的结合被认为会引入压力，从而导致复合物中的两个C1r蛋白（蛋白酶酶原）自身激活，从而产生两种活性的C1r丝氨酸蛋白酶（Morikis，D.和Lambris，JD（2005））。 。这些激活的C1r亚基裂解并激活复合物中的两个C1s蛋白酶酶原。活化的C1裂解补体成分C4，释放出C4a，并启动C4b与活化表面的共价连接。活化的C1也切割C2，并且C2的较大片段结合至表面附着的C4b，形成C4b，C2a，其为经典途径的C3 / C5转化酶。