Difference Between IgG And IgE

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Difference Between IgG And IgE

IgG and IgE are both immunoglobulins but they are not the same as each other. Before we can see the differences between IgG and IgE, lets first understand what immunoglobulins are.

What are immunoglobulins?

Immunoglobulins are glycoproteins which are produced by white blood cells to help fight disease-causing microorganisms. They are also known as antibodies. Immunoglobulins work by  identifying and binding to pathogens like bacteria and cysts. They are produced in response to the invasion of the body by microbes or foreign substances such as allergens and animal dander. They also respond to cancer cells.

There are five major classes of immunoglobulins namely IgM, IgA, IgE, IgD, and IgE. Each of these immunoglobulins performs a different role in the body’s defence mechanism. There is usually a specific type of antibody for each particular microbe. Antibodies designed for Salmonella will therefore only act against Salmonella.

Difference between IgG and IgE

The difference between IgG and IgE can be considered in the following aspects:

Allergic reactions

IgG and IgE are much talked about especially in regard to allergic reactions. Both of them are usually produced by the body in response to the presence of allergens. Although they are both produced during allergic reactions, they are not produced at the same time. IgE is usually the one to be produced first following an allergic reaction, IgG is produced much later after IgE has been produced.

Because of its stronger relation to allergic reactions, modern testing methods for allergies usually only seek to detect IgE reactions. IgE reactions usually take place immediately after exposure to or ingestion of an allergen. IgG reactions on the other usually show up much later after ingestion of an allergens. It may take several hours or even a few days for IgG reactions to occur.

The symptoms of allergic reactions due to IgE and IgG are also different. The symptoms of IgE reactions are usually more severe in comparison to those of IgG reactions. Taking the case of food allergies, symptoms of IgE reactions may include a sudden onset of diarrhoea, abdominal pain, swelling of lip and tongue, bloating, and hives. Food allergy symptoms of IgG however may include bloating, gas, constipation, diarrhoea and abdominal pain. These symptoms are usually subtle.


IgG and IgE are found in different locations in the body. IgG is found in all body fluids. It is infact the most main immunoglobulin in the blood. Of all immunoglobulins in the body, IgG are the smallest in size. They are however the most abundant immunoglobulins in the body. They make up about 75% to 80% of the antibodies in the body.

IgE immunoglobulins on the other hand are found in the lungs, skin, and mucous membranes.

Type of heavy chain

IgG and IgE contain different types of heavy chain. A molecule of IgG contains a heavy chain known as a γ chain while a molecule of IgE contains an ε chain. Heavy chains help in binding antigens. The type of heavy chain present in an immunoglobulin determines its class and effector function. Heavy chains are made up of polypeptides. The different functions of immunoglobulins are influenced by amino acid sequences within the heavy chains.

More about antibodies

Antibodies are produced by a type of white blood cells known as B lymphocyte. B lymphocytes are formed in the bone marrow. When a pathogen invades the body, the immune system triggers B lymphocytes to make antibodies. These antibodies are used to fight the pathogens through processes such as neutralization of pathogen, opsonization, and complement activation. Remaining antibodies are stored in the body

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