A highly specific blood test for vCJD

Jackson, Graham S.; Burk-Rafel, Jesse; Edgeworth, Julie Ann; Sicilia, Anita; Abdilahi, Sabah; Korteweg, Justine; Mackey, Jonathan; Thomas, Claire; Wang, Guosu; Mead, Simon; Collinge, John

doi:10.1182/blood-2013-11-539239

Cited by 24 publications

(17 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Like our PMCA method, the MRC vCJD blood assay displayed an excellent analytical sensitivity and specificity. However about a third of the vCJD blood samples tested so far were score negative (6 out the 21 vCJD affected cases) [26], [55], [56]. The idea of a lower/absence of prionemia in certain vCJD cases is also indirectly supported by the observations recently reported by Mead et al This author reported that in a vCJD affected patient that was negative using the MRC vCJD blood detection assay, the lympho-reticular tissues displayed unusually low PrP Sc accumulation levels [57].…”

Section: Discussionmentioning

confidence: 99%

Preclinical Detection of Variant CJD and BSE Prions in Blood

et al. 2014

View full text Add to dashboard Cite

The emergence of variant Creutzfeldt Jakob Disease (vCJD) is considered a likely consequence of human dietary exposure to Bovine Spongiform Encephalopathy (BSE) agent. More recently, secondary vCJD cases were identified in patients transfused with blood products prepared from apparently healthy donors who later went on to develop the disease. As there is no validated assay for detection of vCJD/BSE infected individuals the prevalence of the disease in the population remains uncertain. In that context, the risk of vCJD blood borne transmission is considered as a serious concern by health authorities. In this study, appropriate conditions and substrates for highly efficient and specific in vitro amplification of vCJD/BSE agent using Protein Misfolding Cyclic Amplification (PMCA) were first identified. This showed that whatever the origin (species) of the vCJD/BSE agent, the ovine Q171 PrP substrates provided the best amplification performances. These results indicate that the homology of PrP amino-acid sequence between the seed and the substrate is not the crucial determinant of the vCJD agent propagation in vitro. The ability of this method to detect endogenous vCJD/BSE agent in the blood was then defined. In both sheep and primate models of the disease, the assay enabled the identification of infected individuals in the early preclinical stage of the incubation period. Finally, sample panels that included buffy coat from vCJD affected patients and healthy controls were tested blind. The assay identified three out of the four tested vCJD affected patients and no false positive was observed in 141 healthy controls. The negative results observed in one of the tested vCJD cases concurs with results reported by others using a different vCJD agent blood detection assay and raises the question of the potential absence of prionemia in certain patients.

show abstract

Section: Discussionmentioning

confidence: 99%

Preclinical Detection of Variant CJD and BSE Prions in Blood

et al. 2014

View full text Add to dashboard Cite

show abstract

“…However, the occurrence of vCJD cases caused by administration of prion-infected human blood has highlighted the realistic opportunity for the development of a blood-based diagnostic test for this condition. Recent developments have shown promise with the detection of vCJD-positive blood samples from clinical vCJD cases by immuno-biochemical selection of disease-associated PrP, without the use of PK [42,43], and by detection of PK-resistant PrPSc following PMCA [44]. Since transmissibility is a defining hallmark of prion diseases, it will be important to develop a reasonably rapid and versatile confirmatory prion infectivity bioassay to supplement these biochemical-based prion diagnostic assays.…”

Section: Discussionmentioning

confidence: 99%

Bioassay of prion-infected blood plasma in PrP transgenic Drosophila

Thackray

Andréoletti

Bujdoso

2016

Biochemical Journal

View full text Add to dashboard Cite

In pursuit of a tractable bioassay to assess blood prion infectivity, we have generated prion protein (PrP) transgenic Drosophila, which show a neurotoxic phenotype in adulthood after exposure to exogenous prions at the larval stage. Here, we determined the sensitivity of ovine PrP transgenic Drosophila to ovine prion infectivity by exposure of these flies to a dilution series of scrapie-infected sheep brain homogenate. Ovine PrP transgenic Drosophila showed a significant neurotoxic response to dilutions of 10−2 to 10−10 of the original scrapie-infected sheep brain homogenate. Significantly, we determined that this prion-induced neurotoxic response in ovine PrP transgenic Drosophila was transmissible to ovine PrP transgenic mice, which is indicative of authentic mammalian prion detection by these flies. As a consequence, we considered that PrP transgenic Drosophila were sufficiently sensitive to exogenous mammalian prions to be capable of detecting prion infectivity in the blood of scrapie-infected sheep. To test this hypothesis, we exposed ovine PrP transgenic Drosophila to scrapie-infected plasma, a blood fraction notoriously difficult to assess by conventional prion bioassays. Notably, pre-clinical plasma from scrapie-infected sheep induced neurotoxicity in PrP transgenic Drosophila and this effect was more pronounced after exposure to samples collected at the clinical phase of disease. The neurotoxic phenotype in ovine PrP transgenic Drosophila induced by plasma from scrapie-infected sheep was transmissible since head homogenate from these flies caused neurotoxicity in recipient flies during fly-to-fly transmission. Our data show that PrP transgenic Drosophila can be used successfully to bioassay prion infectivity in blood from a prion-diseased mammalian host.

show abstract

“…Although previously contested, these findings have been supported by a recent study demonstrating infectivity following intracranial injection of plasma from two sCJD patients into humanized transgenic mice and by the detection of infectivity in the bone marrow from sCJD patients . Attempts have been made to detect PrP TSE in soluble and cellular blood fractions from clinical sCJD patients by biochemical methods following amplification or concentration protocols, but these have yielded either unsuccessful or inconsistent results . This is notable, considering that one of these techniques, protein misfolding cyclic amplification (PMCA), has reliably detected PrP TSE in blood from different experimental models of prion disease as well as vCJD patients .…”

mentioning

confidence: 99%

“…19,23 Attempts have been made to detect PrP TSE in soluble and cellular blood fractions from clinical sCJD patients by biochemical methods following amplification or concentration protocols, but these have yielded either unsuccessful 5 or inconsistent results. 24,25 This is notable, considering that one of these techniques, protein misfolding cyclic amplification (PMCA), has reliably detected PrP TSE in blood from different experimental models of prion disease as well as vCJD patients. 24,[26][27][28] One plausible explanation for the inconsistent detection of PrP TSE in blood from sCJD patients by PMCA relies on differences in conformation of the various prion strains and their specific requirements for in vitro conversion, which may result in ineffective amplification of sCJD prions by this technique (Saá et al, unpublished observations).…”

mentioning

confidence: 99%