Definitions

1. noun

A protein produced by the immune system in response to the presence of a foreign substance, such as a virus or a bacterium, that it recognizes as a threat.

“The doctor explained to the patient how her body produced antibodies to fight off the infection.”

2. noun

A substance that specifically interacts with and neutralizes a particular antigen or toxin.

“The vaccine contained antibodies that helped protect against the flu virus.”