Monoclonal Antibodies- A Novel Advancement in Treating Blood Cancers
Monoclonal Antibodies are considered to be the most novel therapeutic agents in treating cancers. These antibodies are laboratory raised immunological drugs which act against single antigen on the surface of cancer cells. The antibodies are manufactured with the use of hybridoma technology, which involves the fusion of two cells, B- cell and a tumour cell to form a hybrid cell called Hybridoma. Sometimes, our body is unable to recognize the cancer cells as foreign cells, these antibodies marks the cancer cells binds to the surface antigen of the cancer cells and facilitates their killing by various immune cells. The first approach of treating cancer with the use of Monoclonal antibodies started with the use of Rituximab, also known as Rituxan for treating follicular lymphoma. This antibody specifically binds to CD20 marker of the cancerous B cell.
The first monoclonal antibodies formed through hybridoma technology are murine antibodies. Clinical trials on these antibodies were unsuccessful due to dissimilarity between the murine and human immune system. The side effects shown are allergies and anaphylactic shocks. To minimise these side effects, another form of antibodies called chimeric and humanized antibodies were developed.
Monoclonal antibodies can also be classified as naked mAbs and conjugated mAbs. In Naked mAbs, there are no drugs or radioactive materials attached. Whereas, in conjugated mAbs chemotherapeutics or radioactive materials or immunotoxins are attached. A most famous example of naked mAbs is alemtuzumab (Campath®), which is used to treat chronic lymphocytic leukemia.
The monoclonal antibodies block the growth signals by binding to specific receptors. This is advantageous, because growth signals are important for the uncontrolled proliferation of the cells. The process of Antibody-Dependent Cell mediated Cytotoxicity (ADCC) is another mode of their action, in which these antibodies draws effector cells to the cancerous cells and leads their phagocytosis.
The side effects of monoclonal antibodies are mild when compared to chemotherapeutic drugs. The side effects include fever, chills, weakness, nausea, vomiting, low blood pressure etc.