What are the functions of immunoglobulin A (IgA)?

Functions of immunoglobulin A (IgA):

• IgA prevents passage of foreign substances into the circulatory system. 
• It protects mucous membranes with its ability to traverse the epithelial layer and enter into body secretion where it provides local immunity 
• With its abundance in mucosal secretions such as tears and saliva, IgA serves as the primary defense mechanism against some local infections
• IgA neutralizes viruses and prevent them from attaching on host surface in body secretion. 
• Helps to activate the complement pathway when aggregated
• Secretory IgA provides a vital line of defense against several bacteria and can also inhibit inflammatory effects of other immunoglobulins.