Oksana Yakovleva

Similar levels of infectivity in the blood of mice infected with human-derived vCJD and GSS strains of transmissible spongiform encephalopathy.

BACKGROUND: The possible transmission of variant CJD (vCJD) through blood transfusion or use of plasma‐derived products prompted this study comparing infectivity in murine models of vCJD and Gerstmann‐Sträussler‐Scheinker (GSS) disease, a non‐vCJD form of transmissible spongiform encephalopathy (TSE).

First Demonstration of Transmissible Spongiform Encephalopathy-associated Prion Protein (PrPTSE) in Extracellular Vesicles from Plasma of Mice Infected with Mouse-adapted Variant Creutzfeldt-Jakob Disease by in Vitro Amplification

Background: Prions can be transmitted by blood transfusion, but their origin and distribution in blood are unknown. Results: Prions were detected in plasma extracellular vesicles from preclinical and clinically sick mice. Conclusion: Prions associate with blood-circulating extracellular vesicles. Significance: These findings provide information about prion distribution in blood and set the groundwork for novel prion removal and disease diagnosis technologies. The development of variant Creutzfeldt-Jakob disease (vCJD) in three recipients of non-leukoreduced red blood cells from asymptomatic donors who subsequently developed the disease has confirmed existing concerns about the possible spread of transmissible spongiform encephalopathies (TSEs) via blood products. In addition, the presence of disease-associated misfolded prion protein (PrPTSE), generally associated with infectivity, has been demonstrated in the blood of vCJD patients. However, its origin and distribution in this biological fluid are still unknown. Various studies have identified cellular prion protein (PrPC) among the protein cargo in human blood-circulating extracellular vesicles released from endothelial cells and platelets, and exosomes isolated from the conditioned media of TSE-infected cells have caused the disease when injected into experimental mice. In this study, we demonstrate the detection of PrPTSE in extracellular vesicles isolated from plasma samples collected during the preclinical and clinical phases of the disease from mice infected with mouse-adapted vCJD and confirm the presence of the exosomal marker Hsp70 in these preparations.

Effect of protease treatment on plasma infectivity in variant Creutzfeldt‐Jakob disease mice

BACKGROUND:  The emergence of variant Creutzfeldt‐Jakob disease (vCJD) and of a probable transmission of the disease through blood transfusion from a presymptomatic case has underlined the need for a reliable, sensitive, and specific screening test. This study was initiated to explain why attempts to identify protease‐resistant prion protein (PrPres) following treatment with proteinase K (PK) in blood or blood components have so far failed.

Squirrel Monkeys (Saimiri sciureus) Infected with the Agent of Bovine Spongiform Encephalopathy Develop Tau Pathology

Squirrel monkeys (Saimiri sciureus) were infected experimentally with the agent of classical bovine spongiform encephalopathy (BSE). Two to four years later, six of the monkeys developed alterations in interactive behaviour and cognition and other neurological signs typical of transmissible spongiform encephalopathy (TSE). At necropsy examination, the brains from all of the monkeys showed pathological changes similar to those described in variant Creutzfeldt-Jakob disease (vCJD) of man, except that the squirrel monkey brains contained no PrP-amyloid plaques typical of that disease. Constant neuropathological features included spongiform degeneration, gliosis, deposition of abnormal prion protein (PrP(TSE)) and many deposits of abnormally phosphorylated tau protein (p-Tau) in several areas of the cerebrum and cerebellum. Western blots showed large amounts of proteinase K-resistant prion protein in the central nervous system. The striking absence of PrP plaques (prominent in brains of cynomolgus macaques [Macaca fascicularis] with experimentally-induced BSE and vCJD and in human patients with vCJD) reinforces the conclusion that the host plays a major role in determining the neuropathology of TSEs. Results of this study suggest that p-Tau, found in the brains of all BSE-infected monkeys, might play a role in the pathogenesis of TSEs. Whether p-Tau contributes to development of disease or appears as a secondary change late in the course of illness remains to be determined.

Persistent Propagation of Variant Creutzfeldt-Jakob Disease Agent in Murine Spleen Stromal Cell Culture with Features of Mesenchymal Stem Cells

ABSTRACT The transmission of variant Creutzfeldt-Jakob disease (vCJD) through blood transfusions has created new concerns about the iatrogenic spread of transmissible spongiform encephalopathies (TSEs)/prion diseases through blood and plasma-derived products and has increased the need to develop efficient methods for detection of the agent in biologics. Here, we report the first successful generation of spleen-derived murine stromal cell cultures that persistently propagate two mouse-adapted isolates of human TSE agents, mouse-adapted vCJD, and Fukuoka 1. These new cell cultures can be used efficiently for studies of the pathogenesis of the disease, for development of diagnostics and therapeutics, and as a rapid ex vivo assay for TSE inactivation/removal procedures.

Candidate Cell Substrates, Vaccine Production, and Transmissible Spongiform Encephalopathies

Candidate cell substrates neither accumulated abnormal prion protein nor propagated infectivity.

Protease-resistant Prion Protein in Lymphoreticular Tumors of Variant Creutzfeldt-Jakob Disease Mice

We report protease-resistant prion protein (PrPres) in spontaneous lymphoreticular tumors of mice infected with the agent of variant Creutzfeldt-Jakob disease (vCJD). PrPres may accumulate in lymphoreticular system tumors of asymptomatic persons with vCJD. The statistical power of estimates of vCJD prevalence might be increased by expanding screening to include samples of lymphoreticular neoplasms.