Constant region

Definition

The constant region is the part of an antibody's structure that remains the same among different antibodies of the same class. It is responsible for mediating interactions with immune cells and effector functions.

5 Must Know Facts For Your Next Test

1. The constant region is located in the Fc (fragment crystallizable) portion of an antibody.
2. It determines the class (isotype) of the antibody, such as IgG, IgM, IgA, IgE, or IgD.
3. The constant region does not vary between different antibodies of the same class but differs across different classes.
4. It interacts with cell surface receptors and complement proteins to mediate immune responses.
5. Mutations in the constant region can affect an antibody's ability to function properly in immune defense.

Review Questions

• Where is the constant region located on an antibody?
• How does the constant region differ between different classes of antibodies?
• What role does the constant region play in immune system interactions?

Related terms

Variable Region: Part of an antibody that binds specifically to antigens.

Fc Receptor: Cell surface receptor that binds to the Fc region of antibodies.

Complement System:

A group of proteins that enhance immune responses through a cascade effect.