The remarkable specificity of the immune cells to antigens has long drawn the attention of immunologists and oncologists to develop immunotherapies to fight cancer. Recent developments in detailed understanding of the biology of tumor/host immune responses have considerably increased our attention in exploring immunotherapeutic treatment approaches. Two major strategies that are getting clinical validation are, targeting immunosuppression pathways in the tumor microenvironment, and raising the overall tumor antigen specific cytotoxic T cell populations to tilt the balance towards immune specific tumor control.
Relieving the negative signaling pathways (immunosuppression) of T cell activation using antibodies to immune checkpoints such as cytotoxic T lymphocyte antigen (CTLA-4) and programmed death-1 (PD-1)/ programmed death ligand-1 (PDL-1) have emerged as an attractive strategy and are now approved by FDA for treating patients suffering from various cancers. Recently, adoptive T cell therapy using chimeric antigen receptor (CAR) T cells has shown a great promise in clinical trials and is being actively pursued to treat cancers by in vitro rising of T cells. In the context of these advances, active immunotherapy either alone or in combination with other tumor targeted approaches are considered as promising ways to unleash a long-lasting and durable responses to cancer