Cell-based immunotherapy

Immunotherapy is utilizing a patient’s own immune system to fight cancer as well as other diseases. Our immune system is capable of recognizing and eliminating cells that have become infected or damaged or become cancerous. Whereas radiation therapy or chemical therapy target the tumor itself, cancer immunotherapy focuses on boosting the activity of the immune system to erase the tumor. The strategies make use of the fact that many cancer cells express cancer antigens which can be detected by the immune system.

The natural immune response may not be effective against tumors because a tumor may exploit several mechanisms to evade detection by the immune system: For example, the tumor may not express specific antigens or it has major histocompatibility complex (MHC) mutations, so that the immune system does not recognize the tumor. Or, the tumor may produce immune-suppressive molecules that inactivate the immune cells. Thus, boosting the immune response is used to overcome such evasive mechanisms.

In the early days, cancer immunotherapy mainly focused on immuno-stimulatory cytokine treatments. Cytokines, the intercellular signaling molecules of the immune system, can either exert a direct antitumor effect (e.g. TNF-α or Il-6) or indirectly enhance the antitumor immune response (e.g. IL-2 or IFN-α).