Application of a Time‐Resolved Fluoroimmunoassay for the Analysis of Normal Prion Protein in Human Blood and Its Components

Abstract Background and Objectives: To quantify the cellular isoform of prion protein (PrP c ) in human blood using a new time‐resolved dissociation‐enhanced fluoroimmunoas‐say (DELFIA®). Materials and Methods: The DELFIA was optimised for human blood samples and applied to isolated cell and plasma fractions from blood donations. The physicochemical properties of PrP c were analysed. Results: 26.5% of blood PrP c was associated with the platelet fraction, 0.8% with polymorphonuclear leucocytes, 2.4% with mononuclear leucocytes, 1.8% with red cells and 68.5% with plasma (mean values from 4 processed donations). Conclusion: The majority of blood PrP c is found in the platelet and plasma compartments.