Variable region

Definition

The variable region is the part of an antibody or T-cell receptor that varies between different antibodies or receptors and is responsible for binding to specific antigens. This variability allows the immune system to recognize a vast array of pathogens.

5 Must Know Facts For Your Next Test

1. The variable region is located at the tips of the Y-shaped structure of antibodies.
2. It is composed of both heavy and light chains in antibodies.
3. The variability in this region is due to genetic recombination processes such as V(D)J recombination.
4. Variable regions determine the specificity and diversity of the immune response by binding to unique epitopes on antigens.
5. Somatic hypermutation further diversifies the variable regions during an immune response, enhancing antigen affinity.

Review Questions

• What role does the variable region play in antigen recognition?
• How does genetic recombination contribute to the diversity of variable regions?
• What processes contribute to increasing the affinity of antibodies' variable regions for their specific antigens?

Related terms

Constant Region: The part of an antibody or T-cell receptor that remains relatively unchanged and mediates effector functions.

Epitope:

The specific part of an antigen that is recognized and bound by an antibody's variable region.

V(D)J Recombination:

A process during lymphocyte development that generates diverse antibody and T-cell receptor repertoires by rearranging gene segments.