(Press-News.org) The first cases of Mad Cow disease in humans (properly called variant Creutzfeld Jakob Disease, or vCJD) occurred in the late 1990s and are thought to be the consequence of eating contaminated beef products. Since then, several cases of secondary infections caused by transfusions with blood from donors who subsequently developed vCJD have been reported, raising concerns about the safety of blood and blood products. A paper published in PLOS Pathogens on June 12th now describes an assay that can detect prions in blood samples from humans with vCJD and in animals at early stages of the (asymptomatic) incubation phase.
To develop the assay, Olivier Andréoletti, from the Ecole Nationale Vétérinaire de Toulouse, France, and colleagues first optimized a method called PMCA (for Protein Misfolding Cyclic Amplification). The method mimics in a test tube the process by which misfolded (toxic) prions propagate, and the researchers determined experimental conditions that enable efficient PMCA amplification of the vCJD agent in the blood.
Having defined such conditions, they show that the assay can detect vCJD in asymptomatic but infected animals in the early phase of the incubation period. They examined blood samples collected from infected sheep and macaques (vCJD-infected macaques are considered the best model of the human disease). In both models, the assay can accurately identify infected animals and detect the presence of vCJD prions in blood from macaques shortly after the initial infection (and several years before clinical disease onset).
Samples from human vCJD patients are rare, and none exist from individuals at preclinical stage of the disease. To test the assay in human blood, the researchers obtained samples from vCJD patients and non-infected controls and analyzed them blindly (i.e. the people who did the assays did not know which samples were which) in two different laboratories. The assay correctly and consistently identified three of the four vCJD affected patients, and yielded no false-positive result in any of the 141 healthy controls. The negative result in one of the vCJD samples raises the question of the potential absence of vCJD agent in the blood of certain patients.
The authors say their "results represent substantial progress towards an applicable vCJD blood detection assay. Such assay could be used to identify vCJD infected but asymptomatic individuals and/or for screening donated blood for the presence of the vCJD agent".
INFORMATION:
Use this URL to provide readers access to the paper upon publication:
http://dx.plos.org/10.1371/journal.ppat.1004202
Contact:
Olivier Andréoletti
e-mail: o.andreoletti@envt.fr
phone: +33 6 77 18 21 84
Authors and Affiliations:
Caroline Lacroux, Ecole Nationale Vétérinaire de Toulouse, France
Emmanuel Comoy, CEA, Institute of Emerging Diseases and Innovative Therapies (iMETI),France
Mohammed Moudjou, UR892 Virologie et Immunologie Moléculaires Centre de Recherche de Jouy-en-Josas, France
Armand Perret-Liaudet, Hospices Civils de Lyon, France; CNRS, INSERM, UCB Lyon 1, France
Séverine Lugan, Ecole Nationale Vétérinaire de Toulouse, France
Claire Litaise, Ecole Nationale Vétérinaire de Toulouse, France
Hugh Simmons, VLA Weybridge, United Kingdom
Christelle Jas-Duval, EFS-Nord de France, France
Isabelle Lantier, INRA, UMR 1282 Infectiologie et Santé Publique, France
Vincent Béringue, UR892 Virologie et Immunologie Moléculaires Centre de Recherche de Jouy-en-Josas, France
Martin Groschup, Friedrich-Loeffler-Institut, Germany
Guillaume Fichet, UR892 Virologie et Immunologie Moléculaires Centre de Recherche de Jouy-en-Josas, France; Franklab, France
Pierrette Costes, Ecole Nationale Vétérinaire de Toulouse, France
Nathalie Streichenberger, UR892 Virologie et Immunologie Moléculaires Centre de Recherche de Jouy-en-Josas, France
Frederic Lantier, INRA, UMR 1282 Infectiologie et Santé Publique, France
Jean Philippe Deslys, CEA, Institute of Emerging Diseases and Innovative Therapies (iMETI),France
Didier Vilette, Ecole Nationale Vétérinaire de Toulouse, France
Olivier Andréoletti, Ecole Nationale Vétérinaire de Toulouse, France
Please contact plospathogens@plos.org if you would like more information about our content and specific topics of interest. All works published in PLOS Pathogens are open access, which means that everything is immediately and freely available.
Funding: This study was funded by the EU FEDER inter-regional integration program (project 'Con COSTA' EFA205/11. http://www.poctefa.eu/) and the EU FP7 program (project 'Priority'. Project Reference: 222887 http://www.prionpriority.eu/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
Citation: Lacroux C, Comoy E, Moudjou M, Perret-Liaudet A, Lugan S, et al. (2014) Preclinical Detection of Variant CJD and BSE Prions in Blood. PLoS Pathog 10(6):e1004202. doi:10.1371/journal.ppat.1004202
New test detects toxic prions in blood
2014-06-13
ELSE PRESS RELEASES FROM THIS DATE:
Racial survival differences in young dialysis patients significant in poor neighborhoods
2014-06-13
Washington, DC (June 12, 2014) — Among young adult dialysis patients living in poor neighborhoods, blacks have a significantly higher risk of dying while young compared with whites. The findings, which come from a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN), suggest that more work is needed to understand social factors that could worsen outcomes among young black adults with kidney failure.
Among young dialysis patients aged 18 to 30 years, blacks are nearly twice as likely as whites to die while still young. The reasons ...
Hereditary disease genes found throughout the human body
2014-06-13
A new study published in PLOS Computational Biology shows that genes associated with hereditary diseases occur throughout the human body.
The study, by Esti Yeger-Lotem et al., used network biology to model the interactions between proteins associated with diseases such as Parkinson's in different tissues. Using these networks, they show that proteins carrying the disease are found throughout the body.
In tissues vulnerable to hereditary diseases, the networked proteins had unique interactions relevant for the mechanism of the disease. Disease causing genes tend to ...
Processed red meat linked to higher risk of heart failure, death in men
2014-06-12
Men who eat moderate amounts of processed red meat may have an increased risk of incidence and death from heart failure, according to a study in Circulation: Heart Failure, an American Heart Association journal.
Processed meats are preserved by smoking, curing, salting or adding preservatives. Examples include cold cuts (ham, salami), sausage, bacon and hot dogs.
"Processed red meat commonly contains sodium, nitrates, phosphates and other food additives, and smoked and grilled meats also contain polycyclic aromatic hydrocarbons, all of which may contribute to the increased ...
Lower vitamin D level in blood linked to higher premature death rate
2014-06-12
Researchers at the University of California, San Diego School of Medicine have found that persons with lower blood levels of vitamin D were twice as likely to die prematurely as people with higher blood levels of vitamin D.
The finding, published in the June 12 issue of American Journal of Public Health, was based on a systematic review of 32 previous studies that included analyses of vitamin D, blood levels and human mortality rates. The specific variant of vitamin D assessed was 25-hydroxyvitamin D, the primary form found in blood.
"Three years ago, the Institute ...
Study examines religious affiliation and social class
2014-06-12
Lincoln, Neb. — Younger generations are closing the social class gap between evangelical Protestants and mainline denominations, a University of Nebraska-Lincoln sociologist of religion has found.
And in what appears to be an important shift in the U.S. religious landscape, a growing number of younger-generation working-class Americans are not affiliated with any particular religious denomination.
"When lower-class Americans aren't choosing to be evangelical, they're increasingly choosing to be nothing," said Philip Schwadel, associate professor ...
New computer program aims to teach itself everything about anything
2014-06-12
In today's digitally driven world, access to information appears limitless.
But when you have something specific in mind that you don't know, like the name of that niche kitchen tool you saw at a friend's house, it can be surprisingly hard to sift through the volume of information online and know how to search for it. Or, the opposite problem can occur – we can look up anything on the Internet, but how can we be sure we are finding everything about the topic without spending hours in front of the computer?
Computer scientists from the University of Washington and the ...
Grit better than GRE at predicting success in STEM fields
2014-06-12
Selecting graduate students in the fields of science and engineering based on an assessment of their character instead of relying almost entirely on their scores on a standardized test would significantly improve the quality of the students that are admitted and, at the same time, boost the participation of women and minorities in these key disciplines.
That is the argument made in the essay "A test that fails" published in the June 12 issue of the journal Nature. The authors are Associate Professor of Physics Casey Miller of the University of South Florida and Keivan ...
Researchers uncover new insights into developing rapid-acting antidepressant for treatment-resistant depression
2014-06-12
DALLAS – June 12, 2014 – UT Southwestern Medical Center researchers have generated fresh insights that could aid in the development of rapid-acting antidepressants for treatment-resistant depression.
The researchers found that by blocking NMDA receptors with the drug ketamine, they could elicit rapid antidepressant effects in patients with treatment-resistant depression. Ketamine was developed as an anesthetic, but is better known publicly for its abuse as the party drug Special K. Researchers are now seeking alternatives because ketamine can produce side effects that ...
Good bacteria armed with antibiotic resistance protect gut microbiome
2014-06-12
Researchers from Case Western Reserve University in Cleveland have discovered that populating the gastrointestinal (GI) tracts of mice with Bacteroides species producing a specific enzyme helps protect the good commensal bacteria from the harmful effects of antibiotics. Their research is published ahead of print in Antimicrobial Agents and Chemotherapy.
Antibiotics are powerful weapons against pathogens, but most are relatively indiscriminate, killing the good bacteria, along with the bad. Thus, they may render patients vulnerable to invasion, particularly by virulent, ...
Neural reward response may demonstrate why quitting smoking is harder for some
2014-06-12
For some cigarette smokers, strategies to aid quitting work well, while for many others no method seems to work. Researchers have now identified an aspect of brain activity that helps to predict the effectiveness of a reward-based strategy as motivation to quit smoking.
The researchers observed the brains of nicotine-deprived smokers with functional magnetic resonance imaging (fMRI) and found that those who exhibited the weakest response to rewards were also the least willing to refrain from smoking, even when offered money to do so.
"We believe that our findings may ...