Antibodies
Antibodies are tiny proteins your body makes to find and stick to germs so they can be destroyed.
Think of it this way
A tray of cookie cutters each has its own shape: a star, a circle, a square. Each cutter fits only one matching shape of dough and grips it tight. Press the star cutter into round dough and it does not grab. Antibodies work the same way: each one locks onto one germ type and marks it to be cleared.
Explaining antibodies by grade level
When a germ gets inside you, your body knows it does not belong. Your blood makes small things that grab onto the germ. They hold it tight so other parts of your body can get rid of it. Each one is shaped to fit just one kind of germ.