Classes of Antibodies

IgG

Makes up the majority of antibodies in serum and is the only antibody that crosses the placenta from mother to fetus.

Function of IgG

Opsonization, neutralization, and complement fixation.

IgA

Found in secretions such as breast milk and saliva, it functions in agglutination and neutralization.

IgM

First antibody secreted on exposure to an antigen and a potent agglutinating and precipitating agent.

Function of IgM

Complement fixation.

IgE

Binds to mast cells and basophils, triggering their degranulation and facilitating inflammation in the allergic response.

IgD

Antibody found exclusively on the surface of B cells with a role in B cell sensitization and activation.

What is the primary function of IgA in secretions?

Agglutination and neutralization.

Which antibody is the first to be secreted upon exposure to an antigen?

IgM.

What unique ability does IgG have compared to other antibodies?

It can cross the placenta.