IgM

noun

ˌī-(ˌ)jē-ˈem 

1

: a class of immunoglobulins of high molecular weight including the primary antibodies that are released into the blood early in the immune response to be replaced later by IgG and that are highly efficient in binding complement

2

: an antibody of the class IgM

Word History

First Known Use

1969, in the meaning defined at sense 1

Medical Definition

IgM

noun

ˌī-ˌjē-ˈem 

1

: a class of immunoglobulins of high molecular weight that include the primary antibodies released into the blood early in the immune response to be replaced later by IgGs of lower molecular weight and that are highly efficient in binding complement

2

: an immunoglobulin of the class IgM