C1s, Human, clone 10/12

Antibody 10/12 recognizes human activated C1s, a molecule of the complement C1 complex and hence part of the component that initializes classical pathway activation.

Upon recognition of immune complexes by C1q, C1r is autoactivated and subsequently activates C1s, which is then able to cleave C4 and C2, leading to the formation of the C3 convertase and further activation of the terminal pathway of the complement system. C1s deficiencies are associated with impaired function of the classical complement pathway.

The zymogen form of C1s is a glycosylated single chain polypeptide with a MW of around 85kDa and the domain architecture CUB1-EGF-CUB2-CCP1-CCP2-SP, while activation through C1r leads to a 58kDa and a 27kDa chain, linked by disulfide bonds. Monoclonal antibody 10/12 is a murine IgG1 antibody directed against the CCP1-CCP2-SP domains of activated C1s and can detect human C1s in immunoassays.