Prion Neuroinfections

Overview

Prion neuroinfections represent an emergent problem namely after the epidemic brake out of the bovine spongiformencephalopathies, which culminated in 1993. Isolated cases can still emerge. The next case was the discovery ofa new variant of Creutzfeldt-Jakob disease in the comparatively young persons with proved alimentary infectionroute – about 140 cases has been described. Physiological prions are glycoproteins, affixed to the rafts of cellmembranes (namely in neurons) by glycosylphosphatidylinositol anchor. They act as signalling molecules andparticipate in the cooper metabolism. Despite the intensive study in many prestigious laboratories, the way how thepathogenicis oform of prions, given by the prevalence of beta-conformations in the polypeptide chain develops hasnot been proved yet. Pathogenic isoforms are formed intracellulary after the precedent endocytosis. Aggregationsof abnormal prion molecules build up prion amyloid deposits in the form of fibrils or plaques. The loss of neuronsbrings about the neurological symptoms, which are not directly related to the amounts of amyloid deposits.Characteristic findings of spongiosis and the immunohistochemical evidence of protease-resistant prions belong tothe only reliable tests. Reliable intravital test in the blood or urine is not yet available. All forms of human and animaltransmissible spongiform encephalopathies develop only in genetically sensitive individuals. A brief overview ofclinical forms and some biochemical and genetic aspects of the disease are given.

Key words:
humans and animal forms of transmissible spongiform encephalopathy, prion neuroinfections, CJD,vCJD, BSE, scrapie, CWD.