Fan fiction, also called fanfiction, is derivative fiction written using another author's characters and universe. Fanfiction authors write stories about their favorite characters from books, movies, or comics.
Antibodies, also called immunoglobulins, are proteins manufactured by the body that help fight against foreign substances called antigens. When an antigen enters the body, it stimulates the immune system to produce antibodies. (The immune system is the body's natural defense system.) The antibodies attach, or bind, themselves to the antigen and inactivate it. Every healthy adult's body has small amounts of thousands of different antibodies.
Anything that the immune system can detect and attack is called an antigen. The activation of the acquired immune system initially requires the help of other cells. The cells of the acquired immune system are coated in receptors. These are highly specific molecules designed to recognise certain substances.