Questions and Answers
What is IgA mainly known for?
What role does IgA play in local immunity?
IgA attacks microbes and prevents colonization by pathogens before they reach the bloodstream.
IgD has been shown to activate basophils and mast cells.
True
How many forms does IgG come in?
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What percentage of circulating antibodies does IgG make up?
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IgG is the only antibody capable of crossing the placenta.
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What is the main function of IgE?
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What is the function of IgM in the early stages of the immune response?
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Study Notes
Immunoglobulin Classes Overview
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IgA:
- Composed of dimers, featuring two Y-shaped structures.
- Predominantly found in mucosal areas; key sources include saliva, tears, and breast milk.
- Vital for local immunity, it forms a barrier against microbes and prevents pathogen colonization before entering the bloodstream.
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IgD:
- Functions primarily as an antigen receptor on B cells that have not encountered antigens.
- Capable of activating basophils and mast cells, leading to the production of antimicrobial factors.
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IgG:
- Exists in four distinct forms.
- Plays a crucial role in antibody-based immunity and dominates in defense against invading pathogens.
- Constitutes approximately 75% of all circulating antibodies, serving as the body's main defense against bacteria.
- Unique for its ability to cross the placenta, providing immunity to the fetus.
- Known as the most versatile antibody in the immune system.
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IgE:
- Specifically binds to allergens and stimulates histamine release from mast cells and basophils, initiating allergic reactions.
- Protects the body against parasitic infections, particularly parasitic worms.
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IgM:
- Present on the surface of B cells, often in a secreted form that exhibits very high avidity.
- Functions to eliminate pathogens during the initial stages of the B cell-mediated immune response, prior to the production of IgG.
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Description
Explore the different classes of human antibodies through flashcards focusing on their structures and functions. This quiz includes detailed information on IgA, its role in mucosal immunity, and other antibody classes. Perfect for students studying immunology or related fields.
