Immunoglobulins, or antibodies, are important proteins in our body that help fight off germs and infections. There are five main types of immunoglobulins: IgG, IgA, IgM, IgE, and IgD. Each type has its own unique structure and job.
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IgG:
- Structure: This type has one unit and weighs about 150 kDa.
- Function: IgG is the most common antibody in our blood. It makes up 75-80% of antibodies and helps identify and neutralize germs. It also activates other parts of the immune system.
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IgA:
- Structure: IgA usually comes in two units when found in body secretions, and it weighs around 400 kDa.
- Function: This is the main type of antibody found in our mucosal areas, like in our nose and gut. It makes up 80-90% of the antibodies found in secretions, acting as our first line of defense against germs.
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IgM:
- Structure: This type has five units and weighs about 900 kDa.
- Function: IgM is the first antibody produced when our body recognizes a new infection. It makes up around 10-15% of the antibodies and is really good at clumping germs together and activating the immune system.
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IgE:
- Structure: IgE has one unit and weighs about 190 kDa.
- Function: This type is mainly involved in allergic reactions and helps protect against parasites. It is very small, making up less than 1% of the antibodies in our blood.
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IgD:
- Structure: This one has one unit and weighs about 180 kDa.
- Function: IgD mainly acts as a receptor on B cells, which are important for our immune response. Scientists are still figuring out exactly what it does in the blood.
These different types of immunoglobulins help our body respond to a variety of germs in a specialized way.