Patent ID: 7344842

Claim:
A method of testing at least one sample obtained from a mammal for the presence or absence of an aberrant prion protein, the method comprising: preparing said at least one sample as a tissue homogenate and dividing said at least one sample into two aliquots; adding protease inhibitors to one first aliquot, and digesting one second aliquot with a protease, followed by the addition of protease inhibitors, so as to compare results before and after proteolysis; spotting each said aliquot onto a solid phase to prepare a test set and a control set; denaturing peptides contained within said test set with guanidine thiocyanate or one or more chaotropic agents so as to enhance antibody reactivity towards aberrant PrP protein, while antibody reactivity towards normal PrP protein is reduced or unchanged; leaving said control set untreated with guanidine thiocyanate; probing said test set and said control set for PrP protein by immunologically detecting PrP protein by way of an immunoassay with at least one antibody directed against a proteinase K resistant part of the PrP protein; and comparing said test set to said control set wherein an increase in antibody reactivity among the test set after denaturation in guanidine thiocyanate relative to the control set is objective proof of the presence of PrP sc .