antibodies activate the complement system. a complement system consists of a number of small proteins found in the blood. when an antigen attacks the body, the body responds by producing antibody to that antigen. antibody binds to antigen forming an antibody antigen complex. this complex has the ability to activate compliment system. the end result of activation of compliment system is activation of phagocytes that attack foreign cells in the body. activation of compliment also stimulates inflammation that leads to attraction of more phagocytes.