Antibody functions
Antibody | Structure | Where It’s Found / Most Abundant | Main Functions |
|---|---|---|---|
IgG | Monomer | Blood & extracellular fluid (most abundant in serum) | Crosses placenta, opsonization, complement activation |
IgA | Dimer (secretions) | Mucosal surfaces (gut, saliva, tears, breast milk) | Neutralization at mucosal barriers |
IgM | Pentamer | First antibody made during infection (blood/lymph) | Strong complement activation, early defense |
IgE | Monomer | Low in blood; binds mast cells/basophils | Triggers allergic reactions & fights parasites |
IgD | Monomer | On naive B cells (surface-bound) | Unclear role; helps with B cell activation |