Secretory IgA

Definition

Secretory IgA (sIgA) is an immunoglobulin found predominantly in mucosal areas, such as the gut, respiratory tract, and urogenital tract. It plays a crucial role in immune function by preventing colonization by pathogens.

5 Must Know Facts For Your Next Test

1. sIgA is the main antibody found in mucosal secretions like saliva, tears, and breast milk.
2. It is composed of two IgA molecules linked by a J chain and a secretory component.
3. sIgA provides immunity without causing inflammation, which is critical for protecting mucosal surfaces.
4. Deficiency in sIgA can lead to increased susceptibility to infections on mucosal surfaces.
5. sIgA interacts with antigens and pathogens to neutralize them before they penetrate the body's tissues.

Review Questions

• What is the primary role of secretory IgA in the immune system?
• Where are high concentrations of sIgA typically found within the body?
• How does sIgA contribute to immune defense without causing inflammation?

Related terms

Immunoglobulin A (IgA): An antibody that plays a crucial role in mucosal immunity.

Mucosal Immunity: The immune response that protects the body's mucous membranes from infection.

J Chain: A protein component that links two IgA molecules together in secretory IgA.