Antibody and Antigen Binding
An IgG antibody is a Y-shaped protein. The tips of its two arms fit a specific part of an antigen, and its tail signals other immune cells to deal with whatever is bound.
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Labelled parts
Key points
- Binding is specific: the shape and charge of the tip match one epitope, like a key in a lock.
- Each IgG has two identical antigen-binding sites, so it can link two antigens together.
- The Fc tail is recognised by immune cells such as macrophages, which then engulf the target.
Check yourself
Which part of an antibody recognises the antigen?
Check yourself
How many antigen-binding sites does one IgG antibody have?