The question is a bit ambiguous, as there are actually 5 major classes of antibodies (also known as immunoglobulins) in mammals. However, here are three common and important antibodies: IgG, IgA, and IgM.
The five major classes of antibodies are:
- IgG
- IgM
- IgA
- IgE
- IgD
Let's elaborate on IgG, IgA, and IgM:
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IgG (Immunoglobulin G): This is the most abundant type of antibody found in blood and tissue fluids. IgG provides long-term protection against infections. It can cross the placenta to provide passive immunity to the developing fetus. There are different subclasses of IgG (e.g., IgG1, IgG2, IgG3, IgG4) that have slightly different functions.
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IgA (Immunoglobulin A): IgA is primarily found in mucosal areas, such as the gut, respiratory tract, and in secretions like saliva, tears, and breast milk. Its main function is to neutralize pathogens at mucosal surfaces, preventing them from entering the body. It is also passed from mother to baby through breast milk, providing passive immunity.
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IgM (Immunoglobulin M): IgM is the first antibody produced during an initial immune response to an antigen. It's a large antibody, found mainly in the blood and lymph fluid. Its presence indicates a recent infection. IgM is also very effective at activating the complement system, a part of the immune system that helps destroy pathogens.
In summary, while there are five classes of antibodies, IgG, IgA, and IgM are three important ones, each with specific roles in immunity.
