Monoclonal antibody is an antibody that is specific for one antigen and is produced by a B-cell hybridoma. The process of producing monoclonal antibodies was invented by Georges Köhler, César Milstein, and Niels Kaj Jerne in 1975. By the introduction of hybridoma technology monoclonal antibodies have come to play an enormous role in biologic research and applications. They offer the advantages of relative ease of the production and purification of large quantities of antibodies .Hybridoma technology has been replaced by recombinant DNA technology, transgenic mice and phage display .Monoclonal antibodies have had a profound impact on medicine by providing an almost limitless source of therapeutic and diagnostic reagents. Therapeutic use of monoclonal antibodies has become a major part of treatments in various diseases including transplantation, oncology, autoimmune, cardiovascular, and infectious diseases.Monoclonal antibody therapy is the use of monoclonal antibodies to specifically target cells. The main objective is stimulating the patient's immune system to attack the malignant tumor cells and the prevention of tumor growth by blocking specific cell receptors.