B. PolylgA consists of twomlgAmolecules linked end to end with J chain bowling to bolh mlgA subunits via cysteinę (Cys) 471 of one a-chain fromeack monomer
1 Secretory camponent (SC) binds only to polymeric IgA or IgM 2. SC binding by plgA and IgM is dependent on the presence of J chain