Definition of "immunoglobulin" [im•mu•no•glob•ulin]

• Any of a group of large glycoproteins that are secreted by plasma cells and that function as antibodies in the immune response by binding with specific antigens. There are five classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "IgE allergic reactions are immediate; after being exposed to the food, your body quickly overproduces what is called immunoglobulin E antibodies, or IgE."
• "When that invader enters the body, often through the nose, the body tries to protect itself by producing those antibodies called immunoglobulin E IgE."
• "The B cells create chemicals called immunoglobulin antibodies that act like bullets against the foreign substance."