J chain

Definition

The J chain is a protein component that plays a critical role in the polymerization of immunoglobulins IgM and IgA. It facilitates the formation of pentameric IgM and dimeric IgA, enhancing their immune functions.

5 Must Know Facts For Your Next Test

1. The J chain is essential for the secretion of IgM and IgA across mucosal surfaces.
2. It binds to the Fc region of immunoglobulins to form polymeric antibodies.
3. J chain's presence allows these antibodies to bind more effectively to antigens and pathogens.
4. It is involved in mucosal immunity, particularly in protecting against pathogens entering through mucosal linings.
5. The gene encoding for the J chain is located on chromosome 4 in humans.

Review Questions

• What role does the J chain play in antibody structure?
• How does the J chain contribute to mucosal immunity?
• Which immunoglobulins require the J chain for their polymerization?

Related terms

IgM: An immunoglobulin that forms pentamers and is crucial for early-stage immune response.

IgA: An immunoglobulin found predominantly in mucosal areas, forming dimers with the help of the J chain.

Fc Region: The tail region of an antibody that interacts with cell surface receptors and complement proteins.