Your Body: The Missing Manual

Chapter 9. Your Immune System

By this point, you’ve probably realized the sorry truth. Your body is a pastiche, made up of both the amazing and the amazing-it-works-at-all. On one hand, your body features some of the most intricate, finely tuned biological machinery in the natural universe. On the other, it stuffs the gaps with quirks, messy compromises, and more than a few embarrassing shortcuts. It’s a bit like a high-tech supercomputer that’s patched together with duct tape.

Your immune system is no different. You probably think you have a good, basic idea of what it does. Perhaps you imagine something like a crack army of killer cells that hunts down and annihilates disease-causing agents. While this is true to a point, it glosses over several biology Ph.D.s’ worth of details. The reality is that your body has a dizzying array of overlapping defense mechanisms that recruit dozens of different types of specialized body cells and pursue dramatically different strategies. The reason for this complexity is simple—in a battle for your life, it pays to use every weapon at your disposal.

You could easily spend your life studying the human body’s defenses. However, unless you’re hoping to impress a microbiologist on a first date, you don’t need to. Instead, you need to know the basics—how your body defends itself, how you can keep your immune system strong, and how you can close some of its weak links before microscopic marauders exploit them to make you sick.

In this chapter, you’ll cover ...