We just learned about the Antigens that are like signs on pathogen diseases showing what kind of disease they are.
Another part of the immune system is the Antibody.
The antibody is the part of the body that looks for those signs on the antigens to get rid of them.
There are all different types of antibodies, and each one is built like a detective looking for a different type of bad disease.
The antibodies are built in a Y shape, and work with antigens like a lock and key.
If the antibody lock matches the antigen key, then the antibody gets to work getting rid of that antigen to kill the disease.
(from: wikipedia - antibody)
Kid Facts - Blast from the past: Optic Disc