immunology allergic disorders
Complement System
Introduction
The complement system is an enzyme cascade that helps defend against infection. Many complement proteins occur in serum as inactive enzyme precursors (zymogens); others reside on cell surfaces. (See also Overview of the Immune System .) The complement system bridges Overview of the Immune System by Augmenting antibody (Ab) responses and immunologic memory Lysing foreign cells Clearing immune complexes and apoptotic cells Complement components have many biologic functions (eg, stimulation of chemotaxis, triggering of mast cell degranulation independent of immunoglobulin E [IgE]). 