Major functions of Complement include: General functions of antibodies include: Solution Antibodies are immunoglobulin that perform wide funtion- 1.they are the mediator of HUMORAL immune response, antibodies are the first line of defence of our immune system. 2.the Fab portion reognises an antigen, 3.it neutralises a pathogen by binding. 4.it can ativate effetor cells as t lymphoyte,neutrophil,marophages. 5.Antibody mediate hypersensitivity allergic reactions..