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

by Philipp Dettmer

Your immune system is as indispensable as your heart or your lungs. And actually, it is one of the largest and most widespread organ systems throughout your body, although we don’t tend to think about it in these terms.

The immune system is the most complex biological system known to humanity, other than the human brain.

At its very core, the immune system is a tool to distinguish the other from the self.

The goal above all things is maintaining and establishing homeostasis: the equilibrium between all the elements and cells in the body.

it may take a disease days to kill you—your immune system can do so in minutes.

To summarize, distinguishing between self and other is core, homeostasis is the goal, and there are seemingly infinite ways for it to all go wrong.

Your real weak points to infections are your mucous membranes—the surface that lines your windpipe and lungs, eyelids, mouth, and nose, your stomach and intestines, your reproductive tracts and bladder.

An antigen is a piece of an enemy that your immune system can recognize.

For every possible antigen that is possible in the universe, you have the potential to recognize it inside you right now.

How exactly would infections cause autoimmune disease though? While still not entirely answered, a popular idea among immunologists is called molecular mimicry. It basically means that the antigens of microorganisms can be similar in shape to the proteins of your cells, your self-antigens.