An overview of transmissible spongiform encephalopathies

2004 ◽  
Vol 5 (2) ◽  
pp. 103-124 ◽  
Author(s):  
K. Takemura ◽  
M. Kahdre ◽  
D. Joseph ◽  
A. Yousef ◽  
S. Sreevatsan

AbstractTransmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders of humans and animals associated with an accumulation of abnormal isoforms of prion protein (PrP) in nerve cells. The pathogenesis of TSEs involves conformational conversions of normal cellular PrP (PrPc) to abnormal isoforms of PrP (PrPSc). While the protein-only hypothesis has been widely accepted as a causal mechanism of prion diseases, evidence from more recent research suggests a possible involvement of other cellular component(s) or as yet undefined infectious agent(s) in PrP pathogenesis. Although the underlying mechanisms of PrP strain variation and the determinants of interspecies transmissibility have not been fully elucidated, biochemical and molecular findings indicate that bovine spongiform encephalopathy in cattle and new-variant Creutzfeldt–Jakob disease in humans are caused by indistinguishable etiological agent(s). Cumulative evidence suggests that there may be risks of humans acquiring TSEs via a variety of exposures to infected material. The development of highly precise ligands is warranted to detect and differentiate strains, allelic variants and infectious isoforms of these PrPs. This article describes the general features of TSEs and PrP, the current understanding of their pathogenesis, recent advances in prion disease diagnostics, and PrP inactivation.

2001 ◽  
Vol 1 ◽  
pp. 555-556 ◽  
Author(s):  
Markus Glatzel

Transmissible spongiform encephalopathies are a group of invariably fatal neurodegenerative diseases. The infectious agent is termed prion and is thought to be composed of a modified protein (PrPSc or PrPRES), a protease-resistant conformer of the normal host-encoded membrane glycoprotein, PrPC[1]. Bovine spongiform encephalopathy, scrapie of sheep, and Creutzfeldt-Jakob disease are among the most notable transmissible spongiform encephalopathies. Prions are most efficiently propagated trough intracerebral inoculation, yet the entry point of the infectious agent is often through peripheral sites like the gastrointestinal tract[2,3]. The process by which prions invade the brain is termed neuroinvasion[4]. We and others have speculated that, depending on the amount of infectious agent injected, the injection site, and the strain of prions employed, neuroinvasion can occur either directly via peripheral nerves or first through the lymphoreticular system and then via peripheral nerves[5].


Author(s):  
James W. Ironside ◽  
Matthew P. Frosch ◽  
Bernardino Ghetti

This chapter describes and illustrates the neuropathology of prion diseases, also known as transmissible spongiform encephalopathies. These diseases are characterized pathologically by varying combinations of spongiform change, neuronal loss, reactive gliosis, and prion protein (PrP) deposition. The morphologic pattern depends on the etiology of the disease and the genotype of the patient. Different clinicopathological phenotypes of sporadic Creutzfeldt-Jakob disease (CJD) have been described depending on the PRNP codon 129 genotype and the PrP isotype. A novel form known as variably protease-sensitive prionopathy has been recently identified. Familial prion diseases include familial CJD, Gerstmann-Sträussler-Scheinker disease, and fatal familial insomnia. Over 40 different PRNP mutations have been identified. Acquired prion diseases include Kuru; iatrogenic CJD, particularly in recipients of contaminated human pituitary hormone, and variant CJD, which seems closely related to bovine spongiform encephalopathy.


2005 ◽  
Vol 86 (1) ◽  
pp. 241-246 ◽  
Author(s):  
Robert A. Somerville ◽  
Scott Hamilton ◽  
Karen Fernie

Transmissible spongiform encephalopathies (TSEs), sometimes known as prion diseases, are caused by an infectious agent whose molecular properties have not been determined. Traditionally, different strains of TSE diseases are characterized by a series of phenotypic properties after passage in experimental animals. More recently it has been recognized that diversity in the degree to which an abnormal form of the host protein PrP, denoted PrPSc, is glycosylated and the migration of aglycosyl forms of PrPSc on immunoblots may have some differential diagnostic potential. It has been recognized that these factors are affected by the strain of TSE agent but also by other factors, e.g. location within the brain. This study shows in some cases, but not others, that host PrP genotype has a major influence on the degree of PrPSc glycosylation and migration on gels and provides further evidence of the effect of brain location. Accordingly both the degree of glycosylation and the apparent molecular mass of PrPSc may be of some value for differential diagnosis between TSE strains, but only when host effects are taken into account. Furthermore, the data inform the debate about how these differences arise, and favour hypotheses proposing that TSE agents affect glycosylation of PrP during its biosynthesis.


2020 ◽  
pp. 6109-6119
Author(s):  
Simon Mead ◽  
R.G. Will

Prion protein (for proteinacious infectious particle) is a membrane-associated glycoprotein present in all mammalian species. Its normal function is unknown, but in prion diseases (also known as transmissible spongiform encephalopathies) a misfolded polymer form of the protein, partially resistant to protease digestion, is deposited in the brain and associated—typically after long incubation periods—with neuronal dysfunction and death. Prion diseases have become the subject of intense scientific and public interest because they are caused by a biologically distinct disease mechanism and because of the implications for public health following the identification of a new human prion disease, variant Creutzfeldt–Jakob disease (vCJD), and the evidence that it is caused by the transmission to humans of a cattle prion disease, bovine spongiform encephalopathy (BSE).


2005 ◽  
Vol 27 (4) ◽  
pp. 29-32
Author(s):  
S.O. Sowemimo-Coker

Prion diseases (TSEs, transmissible spongiform encephalopathies) are fatal neurodegenerative diseases that affect both humans and animals, including scrapie in sheep, BSE (bovine spongiform encephalopathy) in cattle and CJD (Creutzfeldt–Jakob disease) and its variant (vCJD) in humans. The recent occurrences of probable cases of transmission of vCJD through blood transfusion raises concerns about the safety of the blood supply and the possibility of transmission of the causative agent by blood transfusion from asymptomatic infected individuals.


2021 ◽  
Vol 2 (3) ◽  
pp. 80-94
Author(s):  
Saif Jabbar Yasir ◽  
Taghreed Abdul Kareem Al- Makhzoomy

Prion diseases or transmissible spongiform encephalopathies (TSEs) are a family of rare progressive neurodegenerative disorders that affect both humans and animals. They are distinguished by long incubation periods, characteristic spongiform changes associated with neuronal loss, and a failure to induce inflammatory response. Prion diseases in animals, Scrapie in sheep, chronic wasting disease (CWD) in deer, bovine spongiform encephalopathy (commonly known as "mad cow disease") in cattle, and Creutzfeldt-Jakob disease in humans are all examples of infectious diseases. The prion protein (PrP) was identified in a patient in 2015, and it was previously believed to be the cause of all known mammalian prion diseases. However, The protein alpha-synuclein, which is thought to be responsible for MSA, was suggested to be the cause of the disease in 2015.


1996 ◽  
Vol 17 (8) ◽  
pp. 521-528
Author(s):  
Dominique Dormont

AbstractTransmissible spongiform encephalopathies are rare lethal diseases induced in humans and animals by unconventional agents called transmissible spongiform encephalopathy agents (TSEAs), virions, or prions. Several cases of iatrogenic Creutzfeldt-Jakob disease (CJD) have been reported in the literature after neuro-surgery, treatment with pituitary-derived hormones, corneal grafting, and use of dura mater lyophilisates. In a given infected individual, TSEA-associated infectiousness depends on the nature of the organ: the central nervous system has the highest infectiousness, spleen and lymph nodes a medium infectiousness, and organs such as bone, skin, or skeletal muscles do not harbor any detectable infectiousness in experimental models. Transmissible spongiform encephalopathy/prions have unconventional properties; in particular, they resist almost all the chemical and physical processes that inactivate conventional viruses. Therefore, prevention of CJD agent transmission must be taken into account in daily hospital practice. Efficient sterilization procedures should be determined. In tissue and blood donation, donors with a neurologic history must be excluded, and patients treated with pituitary-derived hormones should be considered potentially infected with TSEA and excluded.


mBio ◽  
2011 ◽  
Vol 2 (3) ◽  
Author(s):  
Christina D. Orrú ◽  
Jason M. Wilham ◽  
Lynne D. Raymond ◽  
Franziska Kuhn ◽  
Björn Schroeder ◽  
...  

ABSTRACT A key challenge in managing transmissible spongiform encephalopathies (TSEs) or prion diseases in medicine, agriculture, and wildlife biology is the development of practical tests for prions that are at or below infectious levels. Of particular interest are tests capable of detecting prions in blood components such as plasma, but blood typically has extremely low prion concentrations and contains inhibitors of the most sensitive prion tests. One of the latter tests is quaking-induced conversion (QuIC), which can be as sensitive as in vivo bioassays, but much more rapid, higher throughput, and less expensive. Now we have integrated antibody 15B3-based immunoprecipitation with QuIC reactions to increase sensitivity and isolate prions from inhibitors such as those in plasma samples. Coupling of immunoprecipitation and an improved real-time QuIC reaction dramatically enhanced detection of variant Creutzfeldt-Jakob disease (vCJD) brain tissue diluted into human plasma. Dilutions of 1014-fold, containing ~2 attogram (ag) per ml of proteinase K-resistant prion protein, were readily detected, indicating ~10,000-fold greater sensitivity for vCJD brain than has previously been reported. We also discriminated between plasma and serum samples from scrapie-infected and uninfected hamsters, even in early preclinical stages. This combined assay, which we call “enhanced QuIC” (eQuIC), markedly improves prospects for routine detection of low levels of prions in tissues, fluids, or environmental samples. IMPORTANCE Transmissible spongiform encephalopathies (TSEs) are largely untreatable and are difficult to diagnose definitively prior to irreversible clinical decline or death. The transmissibility of TSEs within and between species highlights the need for practical tests for even the smallest amounts of infectivity. A few sufficiently sensitive in vitro methods have been reported, but most have major limitations that would preclude their use in routine diagnostic or screening applications. Our new assay improves the outlook for such critical applications. We focused initially on blood plasma because a practical blood test for prions would be especially valuable for TSE diagnostics and risk reduction. Variant Creutzfeldt-Jakob disease (vCJD) in particular has been transmitted between humans via blood transfusions. Enhanced real-time quaking-induced conversion (eRTQ) provides by far the most sensitive detection of vCJD to date. The 15B3 antibody binds prions of multiple species, suggesting that our assay may be useful for clinical and fundamental studies of a variety of TSEs of humans and animals.


2009 ◽  
Vol 89 (4) ◽  
pp. 1105-1152 ◽  
Author(s):  
Adriano Aguzzi ◽  
Anna Maria Calella

Transmissible spongiform encephalopathies (TSEs) are inevitably lethal neurodegenerative diseases that affect humans and a large variety of animals. The infectious agent responsible for TSEs is the prion, an abnormally folded and aggregated protein that propagates itself by imposing its conformation onto the cellular prion protein (PrPC) of the host. PrPCis necessary for prion replication and for prion-induced neurodegeneration, yet the proximal causes of neuronal injury and death are still poorly understood. Prion toxicity may arise from the interference with the normal function of PrPC, and therefore, understanding the physiological role of PrPCmay help to clarify the mechanism underlying prion diseases. Here we discuss the evolution of the prion concept and how prion-like mechanisms may apply to other protein aggregation diseases. We describe the clinical and the pathological features of the prion diseases in human and animals, the events occurring during neuroinvasion, and the possible scenarios underlying brain damage. Finally, we discuss potential antiprion therapies and current developments in the realm of prion diagnostics.


2011 ◽  
Vol 92 (7) ◽  
pp. 1738-1748 ◽  
Author(s):  
Robert A. Somerville ◽  
Nicola Gentles

The causal agents of the transmissible spongiform encephalopathy (TSE) diseases, sometimes called prion diseases, are characterized by high resistance to inactivation with heat. Results from thermal inactivation experiments on nine TSE strains, seven passaged in two PrP genotypes, showed differences in sensitivity to heat inactivation ranging over 17 °C. In addition, the rate of inactivation with increasing temperature varied between TSE models. In some cases passage in an alternative PrP genotype had little effect on the resulting inactivation properties, but for others the infectious agent was inactivated at lower temperatures. No strain with higher thermostability properties was selected. The effect of mixing two TSE strains, to see whether their properties were affected through interaction with each other, was also examined. The results showed that both strains behaved as expected from the behaviour of the unmixed controls, and that the strain responsible for inducing TSE disease could be identified. There was no evidence of a direct effect on intrinsic strain properties. Overall, the results illustrate the diversity in properties of TSE strains. They require intrinsic molecular properties of TSE agents to accommodate high resistance to inactivation and a mechanism, independent of the host, to directly encode these differences. These findings are more readily reconciled with models of TSE agents with two separate components, one of which is independent of the host and comprises a TSE-specific nucleic acid, than with models based solely on conformational changes to a host protein.


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