In the primary response to an antigen, the first class of antibody to be secreted is
A)IgD.
B)IgE.
C)IgG.
D)IgM.
E)IgA.

Question

Quizplus · Accepted Answer

The first class of antibody to be secreted in the primary response to an antigen is IgM. IgM is produced by plasma cells that differentiate from B cells. It is a pentameric antibody that is very effective at agglutinating microbes and activating complement. It is the first antibody made during the primary response, and it acts as an antigen receptor on B cells. It is replaced by IgG later in the primary response.

In the Primary Response to an Antigen, the First Class