Description
Complement C4-B is a non-enzymatic component of C3 and C5 convertases, essential for advancing the classical complement pathway. It binds covalently to immunoglobulins and immune complexes, aiding in the solubilization of immune aggregates and the clearance of immune complexes through CR1 on erythrocytes. C4-B also catalyzes the transacylation of the thioester carbonyl group to form ester bonds with carbohydrate antigens. In mice, Complement C4-B plays a crucial role in activating the classical complement pathway, regulating the immune system, and working in concert with other complement components. Studies have demonstrated that mice lacking C4-B, or with impaired function, may exhibit a predisposition to systemic autoimmune reactions. For instance, the absence or deficiency of C4-B can reduce the selection of self-reactive B cells, thereby affecting immune tolerance