Main Entry: IgM

Pronunciation: \ˌī-(ˌ)jē-ˈem\

Function: noun

Date: 1969

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