Secretory immunoglobulin A (sIgA)

Secretory Immunoglobulin A (sIgA) is a type of antibody primarily found in mucous membranes lining areas such as the mouth, nose, gut, and other respiratory and digestive tracts. It serves as a first line of immune defense by neutralizing harmful germs like bacteria and viruses before they can invade deeper tissues. sIgA is uniquely protected by a secretory component, which helps it resist harsh conditions like stomach acid and enzymes. Its role is crucial for maintaining barrier immunity, preventing infections, and supporting overall mucosal health.