Written by Grace Bernard
Thousands of years ago people just like you and me only had their immune system to combat diseases. Now, we have many medicines available to prevent and treat disease in addition to our own immune defences. These include small molecules and proteins that have undergone intensive testing to be sure they are safe and effective. These medicines are constantly being improved to more selectively target towards a disease process, making them even safer and more effective, similar to the way that guided missiles can strike military targets with great precision compared to the older, unguided ones. In an exciting development, there is also a new cancer treatment called immunotherapy that can be used along with traditional anti-cancer therapies to boost our immune system and redirect it to perform the most important task of killing cancer cells. Basically, immunotherapy teaches our own immune system to fight cancer!
Now you might be thinking, why would we go back to teaching our immune system when we now have so many anti-cancer medicines already? Normally, the immune system patrols the body and raises an alarm when it recognizes something that is foreign and potentially dangerous. The immune system also has ways to prevent cancer, but cancer is tricky because cancer cells are essentially ‘us’, our own cells that have gone rogue and threaten our health. Unfortunately, these cancer cells have developed ways to camouflage themselves from the immune system so that they can blend in with the rest of our healthy cells and continue to multiply in secret until they eventually cause disease.
This is where immunotherapy comes to the rescue! Immunotherapy can be used to train our immune cells to seek and destroy cancer cells. In this scenario, T cells, which are like the body’s soldiers, are removed from the patient’s body and screened to see which ones can recognize the cancer cells; if they cannot recognize the cancerous cells then they are genetically engineered to do so! Scientists then grow millions of those cells in a laboratory before they are injected back into the body in hopes that they will be more effective at attacking the invader. Another way that T cells can be activated against cancer is by altering the immune system’s checkpoints by giving a patient molecules called checkpoint inhibitors. Immune checkpoints are important in the everyday functioning of the immune system because they stop over-activation of different immune cells, like T cells. T cells are constantly looking for invaders and immune checkpoints are there to tell the T cells turned that everything is normal so that they do not attack healthy cells. These checkpoints involve a receptor on the surface of the T cell binding to a protein on the surface of another cell. However, some cancers have learned that if they express this protein, they can hide in plain sight. This is where immune checkpoint inhibitors step in. These molecules block the receptor on the T cell so that it cannot be turned off by the cancer cells!
Although this is a really cool way to treat disease, it is still in its trial phase for treatment. As of right now it is usually used as a last resort for people who have tried all other forms of treatment and have no other options. Currently, scientists are hoping that this will become a mainstream way to treat different types of cancers which have previously proven to be hard to treat with chemically derived compounds. Ultimately, the uses for immunotherapy are endless and it reminds us that sometimes we have to look back at the basics in order to move forward.