Infectivity in bone marrow from sporadic CJD patients
Brief Definitive Report
Infectivity in bone marrow from sporadic CJD patients
Authors
Accepted manuscript online: 9 August 2017 DOI: 10.1002/path.4954
Abstract
Prion infectivity was recently identified in the blood of both sporadic and variant Creutzfeldt-Jakob disease (CJD) patients. In variant CJD (vCJD) the widespread distribution of prions in peripheral tissues of both asymptomatic and symptomatic patients is likely to explain the occurrence of the observed prionaemia. However, in sporadic CJD (sCJD) prion infectivity is described to be located principally in the central nervous system. In this study, we investigated the presence of prion infectivity in bone marrow collected after death in patients affected with different sCJD agents. Bioassays in transgenic mice expressing the human prion protein revealed the presence of unexpectedly high levels of infectivity in the bone marrow from seven out of eight sCJD cases. These findings may explain the presence of blood-borne infectivity in sCJD patients. They also suggest that the distribution of prion infectivity in peripheral tissues in sCJD patients could be wider than currently believed, with potential implications for the iatrogenic transmission risk of this disease.
snip...
Results and discussion
snip...
Results and discussion
We first performed endpoint titrations of one MM1 and one VV2 reference sCJD brain homogenate (10% frontal cortex) in tgMet and tgVal (20 µL intracerebral inoculation) (Table 2). The MM1 and VV2 isolates transmitted in both mouse models. However, both the final end-point dilution and incubation periods indicated that the tgMet mice displayed a higher efficiency than tgVal for the propagation of prion in the MM1 sample. Conversely, the VV2 sample propagated with greater efficiency in tgVal than in tgMet. Based on these results, 10% w/v bone marrow and temporal cortex homogenates from eight different sCJD patients were inoculated (20 µl intracerebral) into tgMet or tgVal according to their PRNP genotype at codon 129 and PrPres type (Table 1).
The inoculation of the brain homogenate from all eight sCJD cases resulted in a 100% transmission rate in the tgHu mice (Table 3). The incubation periods, PrPres western blot patterns (Figure 1) and the lesion profile (Figure 2) in tgMet inoculated with the MM1 sCJD samples were identical to those observed in tgMet inoculated with the MM1 reference sample. Similar observations were made in tgVal mice inoculated with MV/VV2 sCJD samples and the reference VV2 sample. These data strongly support the contention that the prion strains in the brains of MM1 (sCJD 1 to 4) and MV/VV2 (sCJD 5 to 8) patients were similar to those in the MM1 and VV2 reference isolates, respectively.
The inoculation into tgHu mice of all but one (sCJD 8) of the bone marrow homogenates from the sCJD patients resulted in a clinical disease in tgHu mice (Table 3). Bone marrow from a control non-sCJD patient failed to transmit a clinical disease or to cause abnormal PrP accumulation in inoculated tgHu mice.
On first passage, bone marrow-inoculated mice displayed a longer incubation period (and in some instances a lower attack rate) than mice inoculated with the corresponding brain homogenate. However, identical abnormal PrP western blot profiles were seen in brain tissue of mice inoculated with brain or bone marrow from the same single patient. On second passage, incubation periods in groups of tgHu mice inoculated with brain or bone marrow from the same patient mice were similar (Table 3). Moreover, the lesion profiles in the brains of animals that were inoculated with the bone marrow or the brain homogenate from the same patient were identical (Figure 2). These results are consistent with the presence of the same prion strain in the bone marrow and in the brain of the sCJD patients.
Finally, the titres of infectivity in bone marrow and brain homogenates were estimated using the method developed by Arnold et al. [10]. The relationship between the titre of inoculum and the probability of infection and the length of the incubation period were derived from data corresponding to endpoint titration of the MM1 and VV2 reference isolates in tgMet and tgVal mice respectively (Table 2). A normal distribution for the relationship between dose and incubation period was assumed, and the probability of infection versus dose was assumed to follow a logistic regression curve (supplementary material, Figure S1). According to this model, the infectious titre in the positive bone marrow samples was estimated to range between 102.6 and 105.4 ID50 per gram of tissue in tgMet for MM1 patients and from 102.5 to 102.6 per gram in tgVal for the MV/VV2 patients (Table 3).
Together, these results unequivocally demonstrate the presence of prion infectivity in the bone marrow of patients affected by different subtypes of sCJD. These findings contradict the view that in sCJD patients the distribution of prion infectivity in the peripheral tissues is quite limited, and indicate that tissues other than CNS can contain high amount of infectivity [14]. The brain to bone marrow infectivity ratios indicated that in some patients (sCJD 3 and 7) the prion load in one gram of bone marrow was equivalent to the infectivity in up to 10–20 mg of temporal cortex. These values are three to four orders of magnitude higher than those previously observed in the plasma of MM1 sCJD patients [6]. They were also greatly in excess of the level of infectivity measured in the blood of various animal models of transmissible spongiform encephalopathies [15,16]. It is therefore very unlikely that residual blood that might be in bone marrow could explain the levels of infectivity found.
At what disease stage prions accumulate in bone marrow in sCJD is unknown, and the nature of the cells that accumulate or propagate infectivity in this tissue remains to be clarified. Primary cell cultures established from post-mortem bone marrow samples collected from two sCJD affected patients indicated that mesenchymal bone marrow cells could accumulate and replicate prions [17]. Moreover the expression of cellular PrP in haematopoietic stem cells, T and B lymphocyte, monocyte and granulocyte lineages indicates that most haematopoietic cells have the potential capacity to replicate prions [18-20]. Additional experiments are ongoing to determine the role that these different cell lineages could play in the pathobiology of prion diseases. ***Whatever the outcome of these new investigations, the presence of prions in bone marrow supports the view that this tissue might contribute to the prionaemia observed in some sCJD patients.
PLEASE REMEMBER, ALL IATROGENIC CJD IS, IS SPORADIC CJD UNTIL THE ROUTE, SOURCE, THE IATROGENIC EVENT, IS TRACED BACK, THEN DOCUMENTED, THEN PUT INTO THE ACADEMIC DOMAIN, AND FINALLY THE PUBLIC DOMAIN, WHICH VERY SELDOM HAPPENS DO TO THE LONG INCUBATION PERIOD, SURVEILLANCE, AND LACK OF ANY TRACE BACK EFFORTS, thus 85%+ of all human TSE prion disease i.e. sporadic spontaneous CJD...
sporadic/spontaneous cjd is not a single strain, but many strains of cjd, this spontaneous/sporadic term is used as an excuse. all iatrogenic cjd is, is sporadic cjd, until sporadic/spontaneous cjd has now been linked to typical and atypical BSE, to typical and atypical scrapie, and to cwd.
SPONTANEOUS ATYPICAL BOVINE SPONGIFORM ENCEPHALOPATHY
***Moreover, sporadic disease has never been observed in breeding colonies or primate research laboratories, most notably among hundreds of animals over several decades of study at the National Institutes of Health25, and in nearly twenty older animals continuously housed in our own facility.***
THURSDAY, AUGUST 10, 2017
Minimise transmission risk of CJD and vCJD in healthcare settings Updated 10 August 2017
O.05: Transmission of prions to primates after extended silent incubation periods: Implications for BSE and scrapie risk assessment in human populations
Emmanuel Comoy, Jacqueline Mikol, Valerie Durand, Sophie Luccantoni, Evelyne Correia, Nathalie Lescoutra, Capucine Dehen, and Jean-Philippe Deslys Atomic Energy Commission; Fontenay-aux-Roses, France
Prion diseases (PD) are the unique neurodegenerative proteinopathies reputed to be transmissible under field conditions since decades. The transmission of Bovine Spongiform Encephalopathy (BSE) to humans evidenced that an animal PD might be zoonotic under appropriate conditions. Contrarily, in the absence of obvious (epidemiological or experimental) elements supporting a transmission or genetic predispositions, PD, like the other proteinopathies, are reputed to occur spontaneously (atpical animal prion strains, sporadic CJD summing 80% of human prion cases). Non-human primate models provided the first evidences supporting the transmissibiity of human prion strains and the zoonotic potential of BSE. Among them, cynomolgus macaques brought major information for BSE risk assessment for human health (Chen, 2014), according to their phylogenetic proximity to humans and extended lifetime. We used this model to assess the zoonotic potential of other animal PD from bovine, ovine and cervid origins even after very long silent incubation periods.
*** We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period,
***with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold long incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014),
***is the third potentially zoonotic PD (with BSE and L-type BSE),
***thus questioning the origin of human sporadic cases. We will present an updated panorama of our different transmission studies and discuss the implications of such extended incubation periods on risk assessment of animal PD for human health.
===============
***thus questioning the origin of human sporadic cases***
===============
***our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.
==============
Transmission data also revealed that several scrapie prions propagate in HuPrP-Tg mice with efficiency comparable to that of cattle BSE. While the efficiency of transmission at primary passage was low, subsequent passages resulted in a highly virulent prion disease in both Met129 and Val129 mice. Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion. These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
Title: Transmission of scrapie prions to primate after an extended silent incubation period)
*** In complement to the recent demonstration that humanized mice are susceptible to scrapie, we report here the first observation of direct transmission of a natural classical scrapie isolate to a macaque after a 10-year incubation period. Neuropathologic examination revealed all of the features of a prion disease: spongiform change, neuronal loss, and accumulation of PrPres throughout the CNS.
*** This observation strengthens the questioning of the harmlessness of scrapie to humans, at a time when protective measures for human and animal health are being dismantled and reduced as c-BSE is considered controlled and being eradicated.
*** Our results underscore the importance of precautionary and protective measures and the necessity for long-term experimental transmission studies to assess the zoonotic potential of other animal prion strains.
TUESDAY, AUGUST 8, 2017
Concurrence With OIE Risk Designations for Bovine Spongiform Encephalopathy [Docket No. APHIS-2016-0092]
SUNDAY, AUGUST 06, 2017
USA Chronic Wasting Disease CWD TSE Prion Emergency Response Plan Singeltary et al
MONDAY, JULY 17, 2017
National Scrapie Eradication Program May 2017 Monthly Report Fiscal Year 2017
SUNDAY, JULY 30, 2017
Do we need to explain the occurrence of atypical scrapie?
TUESDAY, JULY 18, 2017
USDA announces Alabama case of Bovine Spongiform Encephalopathy Alabama
THURSDAY, JULY 20, 2017
USDA OIE Alabama Atypical L-type BASE Bovine Spongiform Encephalopathy BSE animal feeds for ruminants rule, 21 CFR 589.200
SUNDAY, JULY 23, 2017
atypical L-type BASE Bovine Amyloidotic Spongiform Encephalopathy BSE TSE PRION
SUNDAY, JULY 23, 2017
Experimental Infection of Cattle With a Novel Prion Derived From Atypical H-Type Bovine Spongiform Encephalopathy
Saturday, July 23, 2016
BOVINE SPONGIFORM ENCEPHALOPATHY BSE TSE PRION SURVEILLANCE, TESTING, AND SRM REMOVAL UNITED STATE OF AMERICA UPDATE JULY 2016
Tuesday, July 26, 2016
Atypical Bovine Spongiform Encephalopathy BSE TSE Prion UPDATE JULY 2016
Monday, June 20, 2016
Specified Risk Materials SRMs BSE TSE Prion Program
THURSDAY, JULY 13, 2017
EFSA BSE Sixty cases of mad cow disease since 2001 breached feed ban likely the cause
Scientists investigate origin of isolated BSE cases
SATURDAY, JULY 29, 2017
Risk Advisory Opinion: Potential Human Health Risks from Chronic Wasting Disease CFIA, PHAC, HC (HPFB and FNIHB), INAC, Parks Canada, ECCC and AAFC
PRION 2017 DECIPHERING NEURODEGENERATIVE DISORDERS
Subject: PRION 2017 CONFERENCE DECIPHERING NEURODEGENERATIVE DISORDERS VIDEO
PRION 2017 CONFERENCE DECIPHERING NEURODEGENERATIVE DISORDERS
PRION 2017 CONFERENCE VIDEO
Chronic Wasting Disease CWD TSE Prion to Humans, who makes that final call, when, or, has it already happened?
TUESDAY, JUNE 13, 2017
PRION 2017 CONFERENCE ABSTRACT First evidence of intracranial and peroral transmission of Chronic Wasting Disease (CWD) into Cynomolgus macaques: a work in progress
TUESDAY, JULY 04, 2017
*** PRION 2017 CONFERENCE ABSTRACTS ON CHRONIC WASTING DISEASE CWD TSE PRION ***
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. at
2:27 PM
<< Home