Breakthrough In Prion Amplification Brings Hope Of Blood Test For Variant CJD

Main Category: CJD / vCJD / Mad Cow Disease
Also Included In: Biology / Biochemistry
Article Date: 06 Jul 2007 - 6:00 PDT

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Researchers have shown that a recently developed laboratory method to amplify prions (Protein Misfolding Cyclic Amplification) can be applied to variant CJD (Creutzfeldt-Jakob Disease). The work was carried out by scientists at the National CJD Surveillance Unit at the University of Edinburgh, the Scottish National Blood Transfusion Service, Neuropathogenesis Unit and CSL Behring. It is published this month in the Journal of Pathology.

The team, led by Dr. Mark Head, also shows for the first time that variant CJD prions can be amplified from brain tissue samples using normal blood cells to improve the sensitivity of current detection tests. This method has the potential to be applied on other tissues and fluids, including blood. The prion amplification is dependent on genetic factors, similar to those influencing susceptibility to variant CJD.

Background

Creutzfeldt-Jakob disease (CJD) seems to result from conversion of a normal protein in the body to an abnormal form that is self-replicating as a prion and toxic to the brain. In variant CJD, this occurs after infection by the bovine spongiform encephalopathy (BSE) prion. Following exposure to BSE, there is a long silent period before the prion spreads to the brain and causes neurological symptoms. It is now clear that during this silent period individuals can pass variant CJD prions on to others by blood transfusion and there are also fears that the disease might also be spread by certain kinds of surgery.

One way to protect blood recipients from this threat is to screen blood donations for prions, but efforts to develop such a test have proven difficult, partly because of the very low level of prions that are likely to be present in blood.

The team stress that the work is at an early stage, but co-researcher Professor James Ironside, of the National CJD Surveillance Unit at the University of Edinburgh, said "These new findings provide us with an invaluable tool to study one of the fundamental aspects of variant CJD and take us one step closer towards supporting a test to screen for individuals who might inadvertently pass this disease on to others through blood transfusion, organ donation or surgery."

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Source: Jennifer Beal
John Wiley & Sons, Inc.

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