two proteins were isolated from rat milk by using ion-exchange and gel filtration chromatography and shown to be secretory components by the criteria of : a ) occurrence as free proteins in exocrine secretions , as well as bound to exocrine iga while absent from serum and serum iga , b ) immunohistochemical localization in the epithelial cells of the gut , c ) dissociability from and in vitro binding to 11 s siga , d ) cross-reactivity with antisera to mouse and bovine secretory components , and e ) significant peptide homology with bovine secretory component .
C0020838
siga
C0036538
secretory component