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From: TSS ()
Subject: Mapping PrPSc Propagation in Experimental and Natural Scrapie in Sheep with Different PrP Genotypes
Date: May 4, 2005 at 6:02 pm PST

-------- Original Message --------
Subject: Mapping PrPSc Propagation in Experimental and Natural Scrapie in Sheep with Different PrP Genotypes
Date: Wed, 4 May 2005 20:01:50 -0500
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
To: BSE-L@aegee.org


##################### Bovine Spongiform Encephalopathy #####################

Vet Pathol 42:258-274 (2005)
© 2005 American College of Veterinary Pathologists

Mapping PrPSc Propagation in Experimental and Natural Scrapie in
Sheep with Different PrP Genotypes

C. Ersdal, M. J. Ulvund, A. Espenes, S. L. Benestad, P. Sarradin and T.
Landsverk

Departments of Production Animal Clinical Sciences (CE, MJU) and Basic
Sciences and Aquatic Medicine (CE, AE, TL), Norwegian School of
Veterinary Science, Oslo, Norway; Department of Pathology, National
Veterinary Institute, Oslo, Norway (SLB); and INRA, Tours-Nouzilly,
France (PS)

Twenty-one orally inoculated and seven naturally infected sheep with
scrapie were examined for PrPSc in peripheral tissues and in the central
nervous system (CNS), using immunohistochemistry. In the inoculated
group, VRQ (valine at codon 136, arginine at codon 154 and glutamine at
codon 171)/VRQ sheep generally had a greater accumulation of the
pathologic form of prion protein (PrPSc) in peripheral tissues, as
compared with VRQ/ARQ (alanine at codon 136, arginine at codon 154, and
glutamine at codon 171) animals at corresponding time points after
inoculation. PrPSc was not detected in the ileal Peyer's patch, the
spleen, the superficial cervical lymph node, and peripheral nervous
tissues of several inoculated VRQ/ARQ animals. All inoculated VRQ/VRQ
sheep, but only one of eight inoculated VRQ/ARQ animals, were
PrPSc-positive in the CNS. Thus, the propagation of PrPSc seemed slower
and more limited in VRQ/ARQ animals. Tissue and cellular localization of
PrPSc suggested that PrPSc was disseminated through three different
routes. PrPSc-positive cells in lymph node sinuses and in lymphatics
indicated spreading by lymph. The sequential appearance of PrPSc in the
peripheral nervous system and the CNS, with satellite cells as early
targets, suggested the periaxonal transportation of PrPSc through
supportive cells. Focal areas of vascular amyloid-like PrPSc in the
brain of five sheep, suggested the hematogenous dissemination of PrPSc.
There was a poor correlation between the amount of PrPSc in the CNS and
clinical signs. One subclinically affected sheep showed widespread PrPSc
accumulation in the CNS, whereas three sheep had early clinical signs
without detectable PrPSc in the CNS. A VV136 (homozygous for valine at
codon 136) sheep inoculated with ARQ/ARR (alanine at codon 136, arginine
at codon 154, and arginine at codon 171) tissue succumbed to disease,
demonstrating successful heterologous transmission. Less susceptible
sheep receiving VRQ/VRQ or ARQ/ARR material were PrPSc-negative by
immunohistochemistry, enzyme-linked immunosorbent assay, and western blot.

------------------------------------------------------------------------

Key words: Central; peripheral nervous tissues; ELISA;
immunohistochemistry; lymphoid tissues; placenta; PrPSc; sheep scrapie;
western blot.

Request reprints from Dr. Cecilie Ersdal, Norwegian School of Veterinary
Science, PO Box 8146 Dep, 0033 Oslo (Norway). E-mail:
cecilie.ersdal@veths.no


http://www.vetpathology.org/cgi/content/abstract/42/3/258?etoc

TSS

############ https://www.lists.uni-karlsruhe.de/warc/bse-l.html ############






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