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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