 Monoclonal antibody therapy can aid the immune system because the innate immune system responds to the environmental factors it encounters by discriminating against foreign cells from cells of the body.Therefore, tumor cells that are proliferating at high rates, or body cells that are dying which subsequently cause physiological problems are generally not specifically targeted by the immune system, since tumor cells are the patient's own cells.Tumor cells, however are highly abnormal, and many display unusual antigens.