Monoclonal antibody M241 reacts with an epitope on human C protein activated C1s, a subcomponent of the first component of C (C1). Activated C1s is a glycosylated single-polypeptide zymogen of 85 kD. Activation of the proenzyme C1s occurs through cleavage by the active form of C1r. The activated protease, activated C1s, consists of a disulfide-linked H chain and a L chain. Activated C1s is a serine protease and its catalytic site is located in the L chain. Activation of the classical C pathway is triggered by activated C1s which cleaves C4 and C2 to form the C3 convertase, C4bC2a. The epitope recognised by the antibody M241 is domain IV and/or V of the gamma-domain of activated C1s. Monoclonal antibody M241 blocks C4 activation and C4 binding to activated C1s. The antibody binds specifically to the active centre of C1s.
Flow cytometry, Frozen sections, Functional studies, Immuno assays, Immuno precipitation, Paraffin sections, Western blot
For immunohistology, flow cytometry and Western blotting dilutions to be used depend on detection system applied. It is recommended that users test the reagent and determine their own optimal dilutions. The typical starting working dilution is 1:10. For inhibition of biological activity dilutions have to be made according to the amounts C1s to be inactivated.