What is the primary role of IgA in the immune response?

The primary role of IgA in the immune response is related to mucosal immunity. Immunoglobulin A (IgA) is predominantly found in mucosal secretions, such as saliva, tears, and secretions from the respiratory and gastrointestinal tracts. It serves as a crucial line of defense against pathogens that enter the body through mucosal surfaces.

By binding to pathogens such as bacteria and viruses in mucosal areas, IgA prevents their adhesion and penetration into epithelial cells, thereby limiting infection. This neutralizing activity in the mucosal tissues helps to prevent the invasion of pathogens and contributes significantly to the immune protection of mucosal surfaces.

While IgA can also have secondary roles, such as limiting the spread of infections within the epithelial tissue, its main function revolves around protecting mucosal barrier sites, making it essential for maintaining the integrity and health of these surfaces in the immune system.