List the five classes of antibody heavy chains and provide one function for each.

IgM, IgA, IgE, IgD and IgG

Explanation:

IgM functions in the initial response to offence.

IgA is important for protection of mucus membranes such as in saliva, sweat, tears and gastric fluid.

IgE is active during allergic reactions and defense against infections.

IgD is found on the surface of lymphocytes and is activated upon contact with antigens.

IgG forms part of the secondary response to antigen and is also responsible for newborn protection.