小中大现在有很多针对PrP的抗体是不能区分两种不同的PrP（PrPC和 PrPSc）的，我手头看到的一篇文章说单抗15B3可以特异性识别PrPSc（Korth C, Stierli B, Streit P, Moser M, Schaller O, Fischer R, Schulz-Schaeffer W, Kretzschmar H, Raeber A, Braun U, Ehrensperger F, Hornemann S, Glockshuber R, Riek R, Billeter M, Wuthrich K, Oesch B. Prion (PrPSc)-specific epitope defined by a monoclonal antibody. Nature, 1997, 390(6655): 74-77）。
要判断是PrPC还是 PrPSc，其实可以利用PrPC和 PrPSc对PK（蛋白酶K）的不同抗性来区别，PrPC是不能抵抗PK的消化的，而PrPSc则可以部分抵抗，再利用抗PrP抗体来捕捉，判断是否有留下的PrP片断就可以知道是PrPC还是 PrPSc了。
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Antibody to DNA detects scrapie but not normal prion protein
Communicated by Lynn T. Landmesser, Case Western Reserve University, Cleveland, OH, November 25, 2003 (received for review June 10, 2003)
A conformational change is
believed to convert the normal cellular prion protein into PrPSc.
Detection of PrPSc for diagnosis and prophylaxis is impaired because
available Abs recognizing epitopes on PrP fail to distinguish
between PrPSc and normal cellular prion protein. Here, we report
that an anti-DNA Ab, OCD4, as well as gene 5 protein, a well
established DNA-binding protein, capture PrP from brains affected
by prion diseases in both humans and animals but not from
unaffected controls. OCD4 appears to immunoreact with DNA (or
a DNA-associated molecule) that forms a conformation-dependent
complex with PrP in prion diseases. Whereas PrP immunocaptured
by OCD4 is largely protease-resistant, a fraction of it remains
protease-sensitive. Moreover, OCD4 detects disease-associated PrP
>10 times more efficiently than a widely used Ab to PrP. Our
finding that anti-DNA Abs and gene 5 protein specifically target
disease-associated DNA–PrP complexes in a wide variety of species
and disease phenotypes opens new avenues in the study and
diagnosis of prion diseases.
