BioAcyl Corp

Schematic representations of human dimeric secretory IgA1 and IgA2. Two IgA monomers are depicted tail-to-tail, with a J chain (light gray) covalently linking together one heavy chain tail piece from each monomer. The SC consists of five immunoglobulin-like domains (dark gray) covalently linked at one end, through a disulfide bridge between SC domain V and Cα2 domain on one H chain, whereas noncovalent interactions take place between SC domain I and both the J chain and a Cα3 domain. N-Glycans are shown in black as Y shapes. SIgA2 has one more N-glycan on the Cα2 domain and one (IgA2m(1)) or two (IgA2m(2)) more on the Cα1 domain than SIgA1. O-Glycans are shown as black circles. Four of the five possible sites are shown occupied on the hinge region of SIgA1. There are no O-glycans on the truncated hinge region of SIgA2.