Question

Which among the following following antibodies have a hinge region?

• A. IgG, IgA, IgD
• B. IgG, IgA, IgM
• C. IgM, IgE, IgD
• D. IgE, IgA, IgD

Answer 1

The correct option is A IgG, IgA, IgD

The hinge region is the stretch of the flexible region in the central part, between Fab and Fc regions of the antibody, which makes the antibodies flexible. The main function of the hinge region is to provide flexibility to the Fab arm, so that the antibody can interact with different epitopes of an antigen. The region is rich in amino acids like cysteine, proline etc.

The heavy chains of IgD, IgA and IgG have hinge regions that connect the Fab and Fc which facilitate the individual orientation as well as rotational flexibility of the antibodies.
IgM and IgE do not have a hinge region unlike the other three classes of antibodies.