Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
IgM is a type of antibody that is produced by B-lymphocytes as a part of the body's primary immune response to an antigen. It is the first antibody to be made by the body when it fights a new infection.
Related terms
Antigen: A substance that induces an immune response in the body, especially the production of antibodies.
B: lymphocytes - A type of white blood cell that is part of the adaptive immune system, responsible for producing antibodies against pathogens.
The part of the immune system that adapts its response to specific pathogens it has encountered before, allowing for a more efficient and targeted attack on these pathogens