A comprehensive understanding of the biology of prion diseases is crucial for risk assessment as regards both humans and animals. To further the communication of the current knowledge and the exchange of diagnostic technologies in the scientific community, a symposium on the 'Characterization and Diagnosis of Prion Diseases' was held from September 23-25, 1999 in Tübingen, Germany. The overwhelming interest and the participation of more than 500 scientists from 26 countries made this symposium the largest meeting ever held in the field.
In this Supplementum to Archives of Virology twenty-six invited speakers comprehensively present their data on the pathogenesis of prion diseases in humans and animals, on molecular mechanisms involved in the transmissibility across species barriers, on animal and in-vitro models currently available for the detection and quantification of infectivity and on the characterization of prion strains. This selection attempts to reflect the current state of the art, but cannot possibly represent the whole spectrum of research in the prion field.

Pathogenesis of Prion Diseases.- Prions: from neurografts to neuroinvasion.- Follicular dendritic cells in scrapie pathogenesis.- Cellular and sub-cellular localisation of PrP in the lymphoreticular system of mice and sheep.- Pharmacological manipulation of early PrPres accumulation in the spleen of scrapie-infected mice.- Pathogenesis of natural scrapie in sheep.- Animal Models for Priorn Diseases.- Detection of cattle-derived BSE prions using transgenic mice overexpressing bovine PrPC.- Analyzing the influence of PrP primary structure on prion pathogenesis in transgenic mice.- A single amino acid alteration in murine PrP dramatically alters TSE incubation time.- A transgenic model of a familial prion disease.- Transgenic models of prion disease.- Epidemiology and Diagnosis of Prion Diseases.- Surveillance of BSE.- Histopathology and immunohistochemistry of human transmissible spongiform encephalopathies (TSEs).- Pathology of variant Creutzfeldt-Jakob disease.- Clinical and differential diagnosis of Creutzfeldt-Jakob disease.- Putting prions into focus: application of single molecule detection to the diagnosis of prion diseases.- Detection of PrPSc in subclinical BSE with the paraffin-embedded tissue (PET) blot.- Sheep and goats: natural and experimental TSEs and factors influencing incidence of disease.- Application of Prionics Western blotting procedure to screen for BSE in cattle regularly slaughtered at Swiss abattoirs.- Specific determination of the proteinase K-resistant form of the prion protein using two-site immunometric assays. Application to the post-mortem diagnosis of BSE.- Characterization of the Infectious Agent.- PrPSc typing by N-terminal sequencing and mass spectrometry.- Characterization of BSE and scrapie strains/isolates.- Quantitative traits of prion strains are enciphered in the conformation of the prion protein.- Structure and Function of PrP.- Function of PrPc as a copper-binding protein at the synapse.- The prion protein globular domain and disease-related mutants studied by molecular dynamics simulations.- Neurotoxicity but not infectivity of prion proteins can be induced reversibly in vitro.- PrP Conversion.- Inhibition of formation of protease-resistant prion protein by Trypan Blue, Sirius Red and other Congo Red analogs.- The use of monoclonal antibody epitopes for tagging PrP in conversion experiments.- Listed in Current Contents.