Immunoglobulin A Unit Converter

Immunoglobulin A (IgA) is a type of antibody that plays a crucial role in protecting the body's mucosal surfaces from infections. It is found primarily in secretions such as saliva, tears, breast milk, and the mucous membranes lining the respiratory tract, gastrointestinal tract, and urogenital system.

IgA makes up approximately 15% of the total immunoglobulins in normal serum. Unlike other antibodies that primarily work in the bloodstream, IgA acts as a first line of defense at the body's entry points by neutralizing pathogens before they can invade tissues.

There are two subclasses of IgA: IgA1 (predominant in serum) and IgA2 (more common in secretions). Serum IgA exists mainly as a monomer, while secretory IgA found in mucosal surfaces exists as a dimer linked by a secretory component.

IgA is produced by plasma cells (mature B lymphocytes) located primarily in the mucosal-associated lymphoid tissue (MALT) of the respiratory and gastrointestinal tracts, as well as in the bone marrow, spleen, and lymph nodes.