Normally, antibodies are protective proteins produced by our immune systems to fight bacteria or viruses. Their strength comes from their specificity—when you get ill, B cells in your immune system undergo an exquisitely precise process of accelerated evolution, rapidly optimizing antibodies that bind precisely to whatever is making you unwell, without sticking to any of your body’s own cells. The antibodies can gum up the workings of a marauding germ or mark it for destruction by other parts of the immune system, making antibodies a critical defense against disease in our immune arsenal.
This precise targeting ability also means they’re an attractive tool for use in biology or medicine: You