C1q, Mouse, mAb JL-1,Hycult Biotech,HM1096

The monoclonal antibody JL-1 is highly specific for the collagen-like region (CLR) of mouse C1q , a key component of the classical complement pathway. C1q is a large molecule (459 kDa) composed of three distinct polypeptide chains and plays a central role in immune recognition. The JL-1 antibody was developed by immunizing C1q-deficient ( C1q-/- ) mice (C57BL/6 strain) with purified mouse C1q, ensuring targeted immune response toward this specific region of C1q. C1q in the Classical Complement Pathway C1q is part of the C1 complex , which also includes C1r and C1s , forming the initial component of the classical complement pathway. Upon interaction with immune complexes, C1q undergoes a conformational shift that activates this pathway, essential for immune defense. As the recognition unit, C1q binds to the Fc region of IgG or IgM , provided they are attached to an antigen. Additionally, C1q identifies molecular patterns on pathogens and apoptotic cells, activating the pathway and facilitating phagocytosis . This function is crucial for clearing apoptotic cells, preventing the exposure of autoantigens, and reducing immune system activation. Importance of C1q in Immune Regulation C1q is primarily produced by macrophages , but it is also synthesized by follicular dendritic cells and other cells in the monocyte-macrophage lineage. Deficiency in C1q can lead to impaired clearance of immune complexes and apoptotic cells, contributing to autoimmune conditions such as systemic lupus erythematosus (SLE) . Inherited C1q deficiency has been strongly linked to the development of SLE, as the absence of C1q disrupts normal immune regulation. JL-1 Antibody and Its Role in Research The monoclonal antibody JL-1 specifically targets the collagen-like region of C1q, where autoantibodies bind in both mice and humans. These anti-C1q antibodies are often present in SLE patients and contribute to renal disease , especially in the context of glomerular immune complex disease . This makes JL-1 a valuable tool in studying autoimmune conditions like SLE and the mechanisms of C1q-related immune dysfunction. By focusing on C1q and its pivotal role in the immune system, JL-1 provides insight into immune regulation, complement activation, and the potential development of autoimmune disorders.