Figure 1.

Schematic illustration of structure and glycosylation sites of the IgA isotypes IgA1, IgA2m(1), and IgA2m(2). The light chain is colored in light gray and the heavy chain in dark gray. N-glycans found in the different isotypes are indicated by blue dots. The O-glycans specific for the elongated hinge-region of IgA1 are indicated by orange dots.