Immune: A Journey Into the Mysterious System That Keeps You Alive

by Philipp Dettmer

For example, one of the genius and horrifying methods cancer cells have to protect themselves from the immune system is targeting inhibitor receptors on Killer T Cells and on Natural Killer Cells. Inhibitor receptors inhibit these cells from, well, killing. They are a sort of off switch that deactivates Killer Cells before they can attack a cell and destroy it—which in principle is a good idea. We’ve hit on the fact of how dangerous your immune system is many times, and there need to be mechanisms to stop overeager immune cells, so inhibitor receptors play an important role in the complex concert of your immune system. But unfortunately cancer cells can mutate in a way where they are able to shut down your Killer Cells. So now we have a cancer cell that is able to shut down the defenses of the immune system. And so a new tumor begins growing, producing thousands of new clones that are changing and mutating again.