FAS: The Death Receptor That Keeps the Immune System in Balance

Part I Part II Part III (you are reading this) If you have ever watched a crowd surge toward an emergency, sirens blaring and lights flashing, you have seen the good side of a fast response. But the real test of any system is not only how quickly it mobilizes. It is whether it can stand down once the crisis is over. The immune system faces this exact challenge: it can expand armies of lymphocytes…