TARGETING IMMUNITY TO TREAT CANCERS- A BRIEF REVIEW

Cancer cells have a multitude of mechanisms to avoid and suppress immunity. Normal cells when exposed to chemical carcinogens, irradiation and certain viruses get transformed to cancer cells which can grow indefinitely. These cells have decreased requirements for growth factors; do not undergo apoptosis resulting in malignancy. The tumor cells have various antigens which are responsible for the generation of immune responses towards that particular tumor. There are two types of tumor antigens; tumors specific transplantation antigens (TSTAs) and tumor associated transplantation antigens (TATAs). The TSTAs are specific to tumor, result from mutations which alter the cellular proteins while TATAs may be proteins present in or during some stages of fetal development but not expressed or expressed at low levels in normal adult cells. Adoptive T-cell therapy involves the ex vivo cultivation of T cells with activity against a specific target cancer antigen to increase the frequency of these T cells to achieve therapeutic levels and then infuse them back into the patient. Oncolytic viruses selectively infect, replicate in, and kill tumor cells with no or limited impact on normal tissues which means that tumor cells have surface receptors to bind the virus. Monoclonal antibodies (mAbs) are immunoglobulins derived from a single clone of B cells, act by targeting an antigen which acts a ligand of receptor involved in signal transduction within the cell.