- James Allison of the US and Tasuku Honjo of Japan won the 2018 Nobel Prize in Medicine for their work on Immune checkpoint inhibitor therapy for the treatment of cancer.
- Immune checkpoint inhibitor therapy has revolutionized the way we look at cancer therapy by using our body’s immune system to fight cancer cells.
- While traditional forms of cancer treatment directly targets cancer cells, Immune checkpoint inhibitor therapy help the patient’s own immune system tackle the cancer.
- Thus it is a fundamentally different way of treating cancer.
How does it work?
- T-cells are a type of white blood cells that play a central role in the body’s natural immunity to disease.
- There are certain proteins in immune system cells including cancer cells that act as a break on these t-cells thus affecting the natural defense of the body’s immune system.
- The therapy involves targeting these proteins thus inhibiting the ‘break’ mechanism of these inhibitory proteins, thus restoring the function of t-cells in the body’s immune system.
Immune checkpoint inhibitor therapy
- The discovery found that there are 2 proteins- PD-1 and CTLA-4, that inhibit the action of our immune system.
- The T-cells in the immune system which are basically white blood cells are involved in fighting a foreign body like a cancer cell.
- The proteins PD-1 and CTLA-4 work as brakes in the immune system.
- When these proteins bind with the T-cell, it stops fighting the foreign body and the immune system stops working.
- The proteins can stop the body’s natural defences from killing cancer cells.
- In some cases, some cancer cells also contain these proteins.
- Immune checkpoint inhibitor therapy involves inhibiting these brakes, so that the immune system continues to fight and is capable of fighting against cancer cells.
- Thus by removing these proteins from the equation allows immune cells called T-cells to attack the cancer.
- Inhibiting such brakes has cured lung cancer, renal cancer, lymphoma and melanoma.
Autoimmune reactions: A challenge
- While the treatment is effective in avoiding harmful effects produced by toxins during chemotherapy, it can trigger autoimmune reactions.
- Autoimmune reactions may lead to body’s own cells being treated as foreign bodies and the immune system fights against the healthy cells.