Localization of intracellular immunoglobulin A in porcine intestinal mucosa using enzyme-labelled antibody. An ultrastructural study.

The intracellular localization of IgA in porcine intestinal tissue has been studied by immuno-electron microscopy and immunofluorescence. IgA was demonstrated in vesicles occurring in the cytoplasm of crypt epithelial cells and in the intercellular spaces. It was also shown in the ergastoplasmic cisternae of plasma cells in the intercryptal lamina propria. A model of the selective transport mechanism for IgA, based on these observations is proposed which is consistent with the findings of relatively large amounts of IgA in exocrine secretions and very little in the circulation.