Comparative study of PrPc expression in rat, monkey, and cow gastrointestinal tract

The gastrointestinal tract (GIT) appears to be the main site of entry for the pathological isoform of prions (PrP(sc)). To understand how the PrP(sc) internalization process occurs, it is important to characterize the cell types that express normal prion protein (PrP(c)) along the GIT. To do so, we studied the distribution of PrP(c) in the rat, monkey, and cow GIT. Using Western blot analysis, we found that PrP(c) is expressed in all digestive regions of the three species. Immunoreactivity for PrP(c) was found throughout the GIT in epithelial cells sharing the neuroendocrine (NE) phenotype. Immunostained cells appeared scattered throughout the epithelium of fundic and pyloric glands as well as in intestinal villi and crypts.