What are the differences between the subclasses of immunoglobulin A (IgA)?
Posted July 31, 2024
Basis of differentiation |
Immunoglobulin A1 (IgA1) |
Immunoglobulin A2 (IgA1) |
Percentage of total IgA in serum |
85% |
15% |
Hinge region |
Elongated, increasing sensitivity to bacterial proteases |
Shorter, providing more resistance to proteases |
Protease resistance |
Broad resistance but some proteases can cleave the hinge region |
Good resistance to proteolysis and many bacterial proteases |
Immune response |
Strong response to protein antigens; Moderate response to lipopolysaccharides and polysaccharides |
Plays a crucial role in mucosal immunity, fighting polysaccharide and lipopolysaccharide antigens |
Presence in body |
More than 90% in serum; less prevalent in mucosal secretions |
Predominates in mucosal secretions such as the gastrointestinal tract and airways |
Allotypic variants |
Not specified |
Two variants defined serologically and molecularly - IgA2m(1) and IgA2m(2) |
Disulfide bridges |
Typical disulfide bridges linking light and heavy chains |
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IgA: Structure, Function, and Developability
Purified Mouse Anti-human IgA Secretory Component Antibody *SC-05, monoclonal*