IgA represent about 15 to 20% of immunoglobulins in the blood although it is primarily secreted across the mucosal tract into the stomach and intestines. It is also found in maternal milk, tears and saliva. This immunoglobulin helps to fight against pathogens that contact the body surface, ingested, or inhaled. It does not activate complement and opsonises only weakly. Its heavy chains are of the type ??. It exists in two forms, IgA1 (90%) and IgA2 (10%) that differ in the structure. IgA1 is composed like other proteins, however in IgA2 the heavy and light chains are not linked with disulfide but with noncovalent bonds.Though IgA2 is less in serum, it accounts for major secretory antibody.
View Research related to Immunoglobulin A.