What is the role of the IgA immunoglobulin in the body?

The role of the IgA immunoglobulin in the body is primarily to provide protection on mucosal surfaces. IgA is the most abundant immunoglobulin found in mucosal secretions such as saliva, tears, and breast milk. Its key function is to act as a first line of defense by preventing pathogens from adhering to and penetrating epithelial cells of mucosal surfaces such as those in the respiratory and gastrointestinal tracts. By binding to pathogens in these areas, IgA protects against infections and helps maintain the integrity of mucosal barriers.

This protective function is especially important for neonates, as they acquire IgA through breast milk, which plays a crucial role in protecting their immature immune systems during the early stages of life. This insight underscores the vital importance of IgA in mucosal immunity and its broader implications for infant health and disease prevention.