Characterization of PrPc-immunoreactive cells in monkey (Macaca fascicularis) gastrointestinal tract.

The gastrointestinal tract (GIT) is one of the most likely entry sites for the pathological isoform of prions (PrP(sc)). To understand how PrP(sc) crosses the digestive mucosa, it is crucial to characterize the cells expressing normal prion protein (PrP(c)). By means of double immunofluorescence applied to sections of the monkey GIT, we demonstrated that, in the stomach, PrP(c) immunostaining occurs in subsets of histamine, somatostatin (Som), ghrelin (Ghr), gastrin (G), and serotonin (5HT) cells. In the small and large bowels, PrP(c) cells were found in subpopulations of cells immunolabeled for 5HT, Som, G, and peptide YY (PYY).