Product Description
Mouse complement is famously difficult to assay.Mouse serum rapidly loses its activity and the typical titer of mouse serum is far below the 150-200 CH50 units/mL found with human serum.Mouse strains differ greatly in their complement CH50 titers (Ref 1, 2& 3) and a great many common mouse strains are genetically deficient in C5 (Ref 4 & 5) meaning that they cannot lyse cells even if they have an otherwise fully functional complement system.The exact reasons for low titers in C5 sufficient strains are not entirely clear and they may be different for different mouse strains.However, a common reason is that mouse classical pathway components are not efficiently activated by the standard antibodies bound to EA.At Complement Technology, Inc. we have developed a unique hemolytic reagent (MCAR = Mouse Complement Assay Reagent) that sensitizes sheep erythrocytes to provide improved mouse CH50 titers.For example, commercially available mouse complement exhibited a CH50 of only ~12 units/mL in the assay system described below, however, with MCAR present the CH50 was 217. That is 18-fold higher complement titer with MCAR.This is numerically comparable to normal human serum CH50, but the assays are different.At this time we cannot say how many mouse strains this reagent will work with, but we have used MCAR with three and it worked equally well with all.
Mouse serum is also extremely unstable outside of the mouse.We have observed a rapid loss of activity after thawing (100% loss if left at 4oC overnight).Thus, we advise rapidly thawing NMS and immediately using it in assays or if it is necessary aliquoting and freezing the NMS.It should be thawed rapidly in a water bath, moved immediately to wet ice when thawed, aliquoted and re-frozen as rapidly as possible.Upon use, thaw only when the experimental setup is ready for the NMS sample and keep it on wet ice after thawing.
(For full product description see link...)
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。
