Intra- and Inter-Chain Disulfide Bridges of J Chain in Human S-IgA

S-IgA is synthesized in two steps. First the IgA dimer is linked to the J chain, and afterwards the (IgA)2 J complex is linked to the Secretory Component (SC). Both linkages are accomplished by disulfide exchange and occur at different sites. The linkage of the J chain to IgA is the pre-requisit for the linkage of the SC to the IgA dimer.1