A CELLULAR-FORM OF PRION PROTEIN (PRPC) EXISTS IN MANY NONNEURONAL TISSUES OF SHEEP

A cellular form of the prion protein (PrPC) is thought to be a substra te for an abnormal isoform of the prion protein (PrPSc) in scrapie. Pr PC is abundant in tissues of the central nervous system, but little is known about the distribution of PrPC in non-neuronal tissues of sheep , the natural host of scrapie. This study investigated the tissue dist ribution of PrPC in sheep. Although PrPC was abundant in neuronal tiss ues, it was also detected in non-neuronal tissues such as spleen, lymp h node, lung, heart, kidney, skeletal muscle, uterus, adrenal gland, p arotid gland, intestine, proventriculus, abomasum and mammary gland. N either PrPC nor PrP mRNA was detected in the liver. The tissue distrib ution of PrPC appears to be inconsistent with the tissues which posses s scrapie infectivity, suggesting that factor(s) specific to certain c ell types may be required to support multiplication of the scrapie age nt.