Antibody
Definition
An antibody (immunoglobulin) is a Y-shaped protein produced by B cells of the immune system in response to foreign substances (antigens). Antibodies specifically recognize and bind to antigens, marking them for destruction by other immune cells. There are five classes: IgG, IgA, IgM, IgE, and IgD.
Key Points for NEET
- 1Y-shaped protein with two heavy and two light chains
- 2Variable region binds specific antigen
- 3Five classes: IgG (most common), IgA, IgM, IgE, IgD
- 4Part of humoral (antibody-mediated) immunity
- 5Produced by plasma cells (differentiated B cells)
Example
IgE antibodies triggering allergic reactions when exposed to pollen
Asked in NEET
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