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.
Antigens are the little invaders that enter the body and trigger the immune system. They come in all different shapes and sizes. Antigens are mainly microbes such as bacteria, parasites, and fungi. They can also come from the environment, such as viruses, chemicals, pollen, and more. Each antigen may cause infection to the body. There are some antigens that seem harmless but still cause the immune system to respond, like pollen for example.