Epitope

An epitope is a small region on the surface of a protein or other molecule that your immune system recognizes and targets, like a specific fingerprint that helps your body identify invaders such as viruses or bacteria. When your immune cells encounter an epitope, they bind to it and launch an attack, making epitopes crucial for how vaccines work and how your body develops immunity. Think of it as the "address" that immune cells need to find in order to know they've located an enemy worth fighting.