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Cell cultures can sort out Creutzfeldt-Jacob Disease (CJD) and scrapie infectious agents
October 21, 2005New Haven, Conn. - Research in Japan and at Yale University School of Medicine shows that infection with a weak strain of Creutzfeldt-Jacob Disease (CJD) prevents infection by more virulent strains and that the protection requires persistent replication by the infectious agent, but not misfolded prions.
The "prion diseases" including Mad Cow Disease, scrapie and CJD have been in recent news because of their devastating effects on the brain and concern about transmission of the infectious agents. In prior research on animals, a weaker strain of CJD protected against a more destructive strain.
This study, reported in the journal Science, duplicated and extended results of the animal experiments in a neural cell culture assay. In culture assays it was possible to test human and sheep agent strain combinations that could not be discriminated in animals. These studies showed that a persistent protective CJD infection did not require cells from the immune system or misfolded prions. Cells infected with a weak strain of CJD were also protected from infection by two strains of sheep scrapie agent.
"We demonstrate a new and very sensitive assay for infection by these agents that can discriminate among different strains, such as those that cause sheep scrapie and human CJD," said senior author Laura Manuelidis, professor and section chief of Surgery/Neuropathology at Yale.
According to Manuelidis protection with a weak animal agent may account for the low incidence of CJD linked to Mad Cow Disease in people. "Our plan is to use these rapid infectivity assays to identify the different agents - including those linked to Mad Cow Disease - on the molecular as well as biological levels," said Manuelidis.
"This, as well as our previous results showing that most of the abnormal prion protein can be separated from infectious particles, point to a virus as the causal agent." said Manuelidis "These results are not consistent with the idea that abnormal forms of the prion protein are infectious."
"We demonstrate a new and very sensitive assay for infection by these agents that can discriminate among different strains, such as those that cause sheep scrapie and human CJD," said senior author Laura Manuelidis, professor and section chief of Surgery/Neuropathology at Yale.
According to Manuelidis protection with a weak animal agent may account for the low incidence of CJD linked to Mad Cow Disease in people. "Our plan is to use these rapid infectivity assays to identify the different agents - including those linked to Mad Cow Disease - on the molecular as well as biological levels," said Manuelidis.
"This, as well as our previous results showing that most of the abnormal prion protein can be separated from infectious particles, point to a virus as the causal agent." said Manuelidis "These results are not consistent with the idea that abnormal forms of the prion protein are infectious."
Creutzfeldt-jacob Disease Current Events and Creutzfeldt-jacob Disease News RSSScripps Florida scientists devise accelerated method to determine infectious prion strainsScripps Florida scientists devise accelerated method to determine infectious prion strains
Current tests to identify specific strains of infectious prions, which cause a range of transmissible diseases (such as mad cow) in animals and humans, can take anywhere from six months to a year to yield results - a time-lag that may put human populations at risk.
Scripps scientists develop new tests that identify lethal prion strains quickly and accurately
One of the new in vitro tests, called the Standard Scrapie Cell Assay, measures prion infectivity levels in a highly accurate and extremely rapid way, producing results in less than two weeks.
Prion disease agent causes heart damage in mouse study
These findings raise the possibility that heart infection could be a new aspect of prion diseases, including those that affect humans and livestock, and that these diseases could travel through the blood.
Prion disease infectivity causes heart damage in mouse study
Laboratory mice infected with the agent of scrapie—a brain-wasting disease of sheep—show high levels of the scrapie agent in their heart several hundred days after being infected in the brain, indicating that heart infection might be a new aspect of this disease.
Soil-bound prions that cause CWD remain infectious
Scientists have confirmed that prions, the mysterious proteins thought to cause chronic wasting disease (CWD) in deer, latch on tightly to certain minerals in soil and remain infectious.
vCJD continues to baffle scientists; teenagers disproportionately susceptible
That young people tend to eat more beef products is not enough to explain the strikingly high proportion of new-variant Creutzfeldt-Jacob disease cases among children and adolescents. An article published this week in BMC Infectious Diseases, shows that young people must also be more susceptible to vCJD infection because of their age. New detailed estimates of the UK population's dietary exposure to bovine material according to age have recently become available. Pierre-Yves Bo'Ğlle and his colleagues from Assistance Publique Hôpitaux de Paris and Université Joseph Fourier, Grenoble plugged this information into a mathematical model that predicts the age distribution of vCJD cas
Scientists on track for early diagnosis of neurological diseases
Possible treatments for fatal neurodegenerative diseases such as CJD, Alzheimer's, Parkinson's could result from University of Edinburgh research to find out how specific proteins cause deterioration in brain function. The scientists have discovered for the first time that protein 14-3-3 plays a key role in the development of certain brain diseases by binding to other brain proteins and causing them to malfunction. These findings, described by Professor Alastair Aitken, of the University of Edinburgh School of Biomedical Sciences in the journal Cell, could eventually lead to the development of gene therapy or drug treatments which would disable the harmful proteins. It is already known that
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