This is the next post in our immuno-oncology blog series. Start from the beginning here or follow along as we discuss what chimeric antigen receptor (CAR) T cell actually is.
The future of cancer treatment may lie in immuno-oncology research, particular T cell therapy research, which makes use of the host’s own immune system to fight cancer. This is illuminated in a relatively new approach focused on chimeric antigen receptor (CAR) T cell therapy.
This cutting-edge method involves genetically modifying the host’s own immune cells to fight their cancer. In so doing, it blocks the “invisibility” tumors rely on to protect themselves from attack by the host’s immune system. This, in turn, helps prevent the many health consequences of other cancer treatments, which harm both cancerous and non-cancerous tissue.
The immune system is a complex entity of several cell types, each specialized for a different role on the project of protecting the body from attack.
Some immune cells, such as natural killer cells, are innate, fighting all foreign material inside the host body. Other powerful parts of the immune system are adaptive, becoming active only in response to specific threats.
The B cells that produce antibodies, for example, are adaptive. Each B cell line has an affinity for a particular antigen, and it remains quiescent unless another part of the immune system prods it to start making antibodies against its specific target. These adaptive responses are carefully tailored for certain invaders, which makes them much slower but much more effective than the immune system’s initial, general-purpose or innate defenses.
In addition to antibody-producing B cells, the adaptive immune response also involves T cells. T cells usually have regulatory roles, awakening the rest of the immune system to the presence of a particular invader and mobilizing resources specific to that invader. Some T cells are weapons in their own right. These cytotoxic or “killer” T cells are able to directly attack invaders including: bacteria, cells suffering from viral infection and other pathogens; but they do so only after being alerted by another part of the immune system. An important part of how T cells work is that they all express T cell receptors (TCR) at the cell surface, which are very similar to antibodies and just as specific.
Cytotoxic T cells are effective at destroying cancer cells however an established tumor is usually safe from built-in T cell attack, not because T cells can no longer harm it, but because the tumor has convinced the immune system to ignore it.
But where the body’s innate toolkit runs out, I-O research can fill in. Creating or engineering cytotoxic T cells that can attack tumors even after the body’s unaltered T cells can no longer see them—this is the promise of CAR T cell therapy.
For Research Use Only. Not for use in diagnostic procedures.