NR AWIY
AU Lehto,M.T.; Uger,M.D.; Ostermann,J.; Cashman,N.R.
TI Prion detection in blood using the epitope protection assay
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions DIA-33
PT Konferenz-Poster
AB Amorfix is a theranostics company that uses its Epitope Protection technology to develop new diagnostics and therapeutics for diseases involving misfolded proteins. One such disease, vCJD, is of particular concern for the safety of the blood supply as it cannot be detected in blood by current methods, yet it can be transmitted by blood transfusion. In order to detect prions, an assay must distinguish between the normally folded prion protein PrPc and its aggregated disease-causing conformation PrPsc. Several prion detection assays have used proteolysis to remove PrPc. Since it is unknown what fraction of endogenous prions in blood are protease resistant, we have circumvented this step by developing a chemical means to differentiate between PrPc and PrPsc, called Epitope Protection. PrPc is selectively modified with short-lived and highly-reactive chemicals which modify selected amino acids in the protein. Such chemical modification efficiently blocks immunological epitopes on PrPc and leaves them unrecognizable to many PrP antibodies. PrP molecules within prion particles are "protected" from chemical modification, and can then be detected by conventional immunoassay after disaggregation of the sample. A remaining challenge is the detection in blood of the very small concentration of PrPsc, which has been estimated in the low femtogram range. We have developed an ultrasensitive method using a combination of magnetic and fluorescent beads to detect femtogram quantities of PrP. We have tested this methodology by testing blinded panels of vCJD brain and spleen material spiked into plasma, and we can detect vCJD brain homogenate after diluting a 10% homogenate as much as 105-fold into plasma. Further experiments to validate the assay, such as testing blood from scrapie-infected hamsters at various preclinical time points, as well as testing of blood from human CJD patients, are currently under way.
AD Amorfix Life Sciences Ltd., Toronto, Ontario, Canada
SP englisch
PO Italien