Mammals produce five major classes of immunoglobulins. Indicate whether each of the following descriptions better applies to the immunoglobulin A, D, E, G, or M class. Your answer would be a five-letter string composed of letters A, D, E, G, and M only, e.g. GMADE.
( ) It binds to cells that secrete histamine.
( ) It is the major antibody in secretions such as saliva.
( ) It is the major antibody circulating in the blood.
( ) It is found on the surface of naïve B cells along with IgM.
( ) It forms wheel-like pentamers involved in the primary immune response.

Question

Mammals produce five major classes of immunoglobulins. Indicate whether each of the following descriptions better applies to the immunoglobulin A, D, E, G, or M class. Your answer would be a five-letter string composed of letters A, D, E, G, and M only, e.g. GMADE.
( )	It binds to cells that secrete histamine.
( )	It is the major antibody in secretions such as saliva.
( )	It is the major antibody circulating in the blood.
( )	It is found on the surface of naïve B cells along with IgM.
( )	It forms wheel-like pentamers involved in the primary immune response.

Quizplus · Accepted Answer

Each of the five major classes of immunoglobulins in mammals mediates a characteristic response. IgM and IgD are expressed as B cell receptors on the surface of naïve B cells. In its secreted form, IgM forms pentamers. The major antibody class in the blood is IgG. The principal antibody class in secretions such as saliva is IgA. IgE antibodies bind to Fc receptors on the surface of mast cells and basophils, which are involved in allergy.

Mammals Produce Five Major Classes of Immunoglobulins