How Immunotherapy Is Used To Treat Cancer

Adoptive T-Cell Therapy

Adoptive T-cell therapy attempts to boost the body’s natural ability to fight cancer. Specifically, it does this through the body’s T cells, a certain type of white blood cell. These cells contain receptors, which are their own proteins. These bind to foreign antigens, triggering the immune system to destroy foreign particles. In this treatment, doctors will take T cells harvested from a cancerous tumor to the lab and modify them so they are better able to spot foreign antigens and specific cancer cells. This process can take anywhere from two to eight weeks, at which point they are reintroduced to the body through a needle.

Immune Checkpoint Inhibitors

The immune system must be able to identify the difference between normal and foreign cells, as this allows it to target the foreign cells while leaving normal cells untouched. Every immune system does this by creating checkpoints, which act as stop signals to keep the body in check and trigger (or prevent) an immune system response. Unfortunately, cancer can often find ways to prevent being attacked by modifying the checkpoints, such as creating premature stops. This is where immune checkpoint inhibitors — which target PD-1, PD-L1, or CTLA-4 — come into play.

PD-1 is a T cell checkpoint protein preventing the T cell from attacking other non-cancerous cells in the body by acting as an off-switch when it attaches itself to PD-L1, another protein on some cells. However, some cancer cells contain PD-L1, which allows them to avoid immune attack. PD-1 or PD-L1 inhibitors stop the binding to cancer cells and boost the immune system’s attack response. CTLA-4 is another protein that acts as an off switch in the body. CTLA-4 inhibitors are designed to bind to CTLA-A and prevent its function, which boosts the immune system’s response.