An Elegant Defense: The Extraordinary New Science of the Immune System: A Tale in Four Lives

by Matt Richtel

Part of the way that Hodgkin’s and other cancers disguise themselves is by tricking the T cells that would ordinarily help kill off the mutation. What the cancer does is send a signal to the T cell to self-destruct. Why would the T cell do that? Why would it even have such a receptor on its surface capable of receiving a self-destruct signal? It’s because the immune system has many mechanisms that are aimed at slowing it down, shutting it off, keeping it from overheating. Cancers take advantage of these fail-safe mechanisms to survive. The self-destruct receptor on the T cell is called programmed death. For short, PD. On the cancer is a molecule called PDL-1, a programmed death ligand that binds to or connects to the PD receptor on the T cell. Inside Jason’s body, malignant B cells had grown and were using PDL-1 to put the brakes on the killing part of his immune system. At the same time, now that the immune system had received a message that the cancer was “self” and not alien, the immune system actually set out to protect and support the cancer.