Monoclonal antibody 7H8 recognizes mouse CIq. Clq is a member of the'defense collagen' family and the first subcomponent of the Cl complex of the classical pathway of complement activation. Pattern recognition molecule Clq is endowed with multiple functions, including antibodies Dependent and independent immune functions, such as triggering rapidly enhanced phagocytosis, leading to the effective containment or removal of cell debris, apoptotic cells and immune complexes of pathogens, and are believed to be mediated by Clq receptors present on the surface of effector cells Regarding the uncertainty about the identity of the receptor that mediates Clq function, some previously described Clq receptor molecules, such as gClqR and cClqR, now seem to play less role in Clq function than functions that are not related to Clq. Zygote Clq-deficient mice suggest that Clq plays a role in regulating humoral immune responses and can also prevent the development of autoimmunity.
The first component of complement C1 is a complex of three glycoproteins-Clq, Clr and Cls. Cls and Clr interact to form a Cazf-dependent tetrameric enzyme complex C lr, -C 1 s2, which is in contact with the Clq collagen domain. The binding of Clq to immune complexes (IgG or IgM) through the gClq domain is believed to induce conformational changes in the collagen region of Clq, leading to the self-activation of Clr, which in turn activates Cls. The activated C1 complex then cleaves components C4 and C2 in the classical complement cascade.