A SOLUBLE FORM OF PRION PROTEIN IN HUMAN CEREBROSPINAL-FLUID - IMPLICATIONS FOR PRION-RELATED ENCEPHALOPATHIES

The cellular prion protein (PrPC) is a 33-35 kDa sialoglycoprotein anchored to the external surface of neural and non-neural cells by a glycosyl phosphatidylinositol moiety. In addition, a secretory form of PrPC has been found in cell-free translation systems and in cell cultures. On this basis, we investigated human cerebrospinal fluid for the presence of soluble PrP and identified a protein whose molecular weight, antigenic determinants, N-terminal amino acid sequence and sensitivity to protease digestion corresponded to those of PrPC. In prion-related encephalopathies of humans and animals, the secretory form of PrPC might be converted into the abnormal isoform PrPSc and play a role in the dissemination of the disease process and amyloid formation. © 1992 Academic Press, Inc.