The main class of antibody that is secreted by plasma cells immediately after the initial exposure to any antigen is
A)IgA
B)IgG
C)IgE
D)IgD
E)IgM

Question

Quizplus · Accepted Answer

IgM is the first antibody produced by the immune system in response to an initial exposure to any antigen. It is a pentameric molecule made up of five monomers and is responsible for activating complement system. IgM is eventually replaced by other isotypes such as IgG upon subsequent exposure to the same antigen.

The Main Class of Antibody That Is Secreted by Plasma