Antibodies of the Different Classes IgM, IgG, IgA, IgD, and IgE

Question

Antibodies of the different classes IgM, IgG, IgA, IgD, and IgE differ from each other
A) in the way they are produced.
B) in their heavy-chain structure.
C) in the type of cell that produces them.
D) by the antigenic determinants that they recognize.
E) by the number of carbohydrate subunits they have.

Accepted Answer

The heavy-chain structure of the antibodies differs between the classes. IgM has a pentameric structure composed of five heavy chains and five light chains, while IgG, IgA, IgD, and IgE have a monomeric structure composed of two heavy chains and two light chains.

Answer: A, C, D
 IgM is primarily produced during the primary immune response, while IgG, IgA, IgD, and IgE are produced during the secondary immune response. IgM is produced by B cells, while IgG, IgA, IgD, and IgE are produced by plasma cells. Each class of antibody recognizes specific antigenic determinants, with IgM recognizing mainly surface antigens, IgG recognizing soluble antigens, IgA recognizing mucosal pathogens, IgD involved in B cell activation, and IgE recognizing allergens.

Answer: E
 The number of carbohydrate subunits can vary within a class, but does not differentiate between the different classes of antibodies.