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From: TSS ()
Date: March 1, 2005 at 12:27 pm PST

PNAS | March 1, 2005 | vol. 102 | no. 9 | 3501-3506

Diagnosis of human prion disease

Jiri G. Safar *, {dagger} {ddagger} , Michael D. Geschwind {dagger} , § , Camille Deering *, Svetlana Didorenko *, Mamta Sattavat ¶, Henry Sanchez ¶, Ana Serban * {ddagger} , Martin Vey ||, Henry Baron **, Kurt Giles *, {dagger} {ddagger} , Bruce L. Miller {dagger} , § , Stephen J. DeArmond * {ddagger} , ¶ and Stanley B. Prusiner *, {dagger} {ddagger} , {dagger} {dagger} , {ddagger} {ddagger}

*Institute for Neurodegenerative Diseases, § Memory and Aging Center, and Departments of {dagger} Neurology, ¶Pathology, and {dagger} {dagger} Biochemistry and Biophysics, University of California, San Francisco, CA 94143; ||ZLB Behring, 35041 Marburg, Germany; and **ZLB Behring, 75601 Paris, France

Contributed by Stanley B. Prusiner, December 22, 2004

With the discovery of the prion protein (PrP), immunodiagnostic procedures were applied to diagnose CreutzfeldtJakob disease (CJD). Before development of the conformation-dependent immunoassay (CDI), all immunoassays for the disease-causing PrP isoform (PrPSc) used limited proteolysis to digest the precursor cellular PrP (PrPC). Because the CDI is the only immunoassay that measures both the protease-resistant and protease-sensitive forms of PrPSc, we used the CDI to diagnose human prion disease. The CDI gave a positive signal for PrPSc in all 1024 brain regions (100%) examined from 28 CJD patients. A subset of 18 brain regions from 8 patients with sporadic CJD (sCJD) was examined by histology, immunohistochemistry (IHC), and the CDI. Three of the 18 regions (17%) were consistently positive by histology and 4 of 18 (22%) by IHC for the 8 sCJD patients. In contrast, the CDI was positive in all 18 regions (100%) for all 8 sCJD patients. In both gray and white matter, {approx} 90% of the total PrPSc was protease-sensitive and, thus, would have been degraded by procedures using proteases to eliminate PrPC. Our findings argue that the CDI should be used to establish or rule out the diagnosis of prion disease when a small number of samples is available as is the case with brain biopsy. Moreover, IHC should not be used as the standard against which all other immunodiagnostic techniques are compared because an immunoassay, such as the CDI, is substantially more sensitive.

CreutzfeldtJakob disease | detection | endpoint titration | immunoassay | neurodegeneration

Author contributions: J.G.S. and S.B.P. designed research; M.D.G., C.D., S.D., M.S., H.S., and S.J.D. performed research; A.S., M.V., and H.B. contributed new reagents/analytic tools; J.G.S., K.G., B.L.M., S.J.D., and S.B.P. analyzed data; and J.G.S., S.J.D., and S.B.P. wrote the paper.

Abbreviations: CDI, conformation-dependent immunoassay; CJD, CreutzfeldtJakob disease; sCJD, sporadic CJD; fCJD, familial CJD; iCJD, iatrogenic CJD; IHC, immunohistochemistry; PrP, prion protein; PrPC, normal cellular PrP; PrPSc, disease-causing PrP; HuPrP, human PrP; MHu2M, chimeric mousehuman transgene; sPrPSc, protease-sensitive PrPSc; rPrPSc, protease-resistant PrPSc; PTA, phosphotungstate; PK, proteinase K; H&E, hematoxylin and eosin; Tg, transgenic; (D - N), difference in Ab-binding between native and denatured samples.

{ddagger} J.G.S., S.J.D., A.S., K.G., and S.B.P. have financial interest in InPro Biotechnology, Inc.

{ddagger} {ddagger} To whom correspondence should be addressed at: Institute for Neurodegenerative Diseases, University of California, Box 0518, San Francisco, CA 94143-0518. E-mail: .

© 2005 by The National Academy of Sciences of the USA


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