 |
From: TSS (216-119-162-38.ipset44.wt.net)
Subject: Identification of a second bovine amyloidotic spongiform encephalopathy: Molecular similarities with sporadic Creutzfeldt–Jakob disease (FULL TEXT)
Date: February 17, 2004 at 12:43 pm PST
-------- Original Message --------
Subject: Identification of a second bovine amyloidotic spongiform encephalopathy: Molecular similarities with sporadic Creutzfeldt–Jakob disease (FULL TEXT)
Date: Tue, 17 Feb 2004 14:06:14 -0600
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
To: BSE-L@uni-karlsruhe.de
######## Bovine Spongiform Encephalopathy #########
Identification of a second bovine amyloidotic
spongiform encephalopathy: Molecular similarities
with sporadic Creutzfeldt–Jakob disease
Cristina Casalone*†, Gianluigi Zanusso†‡, Pierluigi Acutis*, Sergio
Ferrari‡, Lorenzo Capucci§, Fabrizio Tagliavini¶,
Salvatore Monaco‡, and Maria Caramelli*
*Centro di Referenza Nazionale per le Encefalopatie Animali, Istituto
Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d’Aosta, Via
Bologna, 148,
10195 Turin, Italy; ‡Department of Neurological and Visual Science,
Section of Clinical Neurology, Policlinico G.B. Rossi, Piazzale L.A.
Scuro, 10, 37134
Verona, Italy; §Istituto Zooprofilattico Sperimentale della Lombardia ed
Emilia Romagna, Via Bianchi, 9, 25124 Brescia, Italy; and ¶Istituto
Nazionale
Neurologico ‘‘Carlo Besta,’’ Via Celoria 11, 20133 Milan, Italy
Edited by Stanley B. Prusiner, University of California, San Francisco,
CA, and approved December 23, 2003 (received for review September 9, 2003)
Transmissible spongiform encephalopathies (TSEs), or prion diseases,
are mammalian neurodegenerative disorders characterized
by a posttranslational conversion and brain accumulation of an
insoluble, protease-resistant isoform (PrPSc) of the host-encoded
cellular prion protein (PrPC). Human and animal TSE agents exist as
different phenotypes that can be biochemically differentiated on
the basis of the molecular mass of the protease-resistant PrPSc
fragments and the degree of glycosylation. Epidemiological, molecular,
and transmission studies strongly suggest that the single
strain of agent responsible for bovine spongiform encephalopathy
(BSE) has infected humans, causing variant Creutzfeldt–Jakob disease.
The unprecedented biological properties of the BSE agent,
which circumvents the so-called ‘‘species barrier’’ between cattle
and humans and adapts to different mammalian species, has raised
considerable concern for human health. To date, it is unknown
whether more than one strain might be responsible for cattle TSE
or whether the BSE agent undergoes phenotypic variation after
natural transmission. Here we provide evidence of a second cattle
TSE. The disorder was pathologically characterized by the presence
of PrP-immunopositive amyloid plaques, as opposed to the lack of
amyloid deposition in typical BSE cases, and by a different pattern
of regional distribution and topology of brain PrPSc accumulation.
In addition, Western blot analysis showed a PrPSc type with
predominance of the low molecular mass glycoform and a protease-
resistant fragment of lower molecular mass than BSE-PrPSc.
Strikingly, the molecular signature of this previously undescribed
bovine PrPSc was similar to that encountered in a distinct subtype
of sporadic Creutzfeldt–Jakob disease.
The transmissible spongiform encephalopathies (TSEs), or
prion diseases (1), encompass a group of progressive neurodegenerative
disorders, including Creutzfeldt–Jakob disease
(CJD) in humans, scrapie in sheep, and bovine spongiform
encephalopathy (BSE) (1–4). These disorders are characterized
by brain deposition of an insoluble, protease-resistant isoform of
the host-encoded cellular prion protein (PrPC), named PrPSc (1,
4, 5) In different TSE phenotypes, PrPSc exhibits disease-specific
properties, including distinctive cleavage sites after proteolytic
treatment, ratio of glycoforms, and deposition patterns, all
features useful in providing a means of strain identification
(6–10).
Although not contagious, TSEs are potentially infective, and
in humans may present as sporadic, inherited, and acquired
diseases. Human-to-human transmission of TSE is well documented
and has occurred either through oral or mucocutaneous
route of infection, as in kuru (11), or after medical and surgical
procedures, as in iatrogenic CJD (12). Recently, animal-tohuman
transmission has also occurred. Epidemiological (13),
experimental transmission (14), and biochemical PrPSc typing
(8) have provided strong evidence that the single prion strain
responsible for BSE has infected humans, causing variant CJD
(vCJD), in addition to several animal species. In BSE and
BSE-related disorders, including vCJD, the molecular typing of
disease-associated PrPSc shows identical PrP fragment sizes and
predominance of the high molecular mass glycoform both in
natural hosts and in experimentally inoculated animals. To date,
at variance with CJD in humans and scrapie in sheep, only a
single strain and a single PrPSc type have been detected in BSE.
The spreading of the BSE agent across mammalian species
barriers has aroused considerable concern for the following
reasons: (i) the possible existence of new or previously unrecognized
cattle TSE strains, potentially pathogenic for humans;
and (ii) the occurrence of phenotypic variation of the BSE strain,
with propagation of a new agent encoding distinctive molecular
and biological properties.
In Italy, an active surveillance system on BSE in cattle was
started in January 2001, and by August 2003 a total of 103 BSE
cases had been diagnosed of 1,638,275 statutory tested brainstem
samples. Confirmatory positive results have been obtained in all
cases by immunohistochemical and Western immunoblot demonstration
of disease-specific protease-resistant PrPSc.
To assess molecular and neuropathological characteristics in
Italian BSE cases, we have over the last few months collected
whole brains of eight Italian cattle that were PrPSc-positive in
Western immunoblots. In two cattle, older than other affected
bovines, the PrPSc glycotype was clearly different from the
BSE-associated PrPSc molecule, and widespread PrP-amyloid
plaques were seen in supratentorial brain regions. Unlike typical
BSE, the brainstem was less involved and no PrP deposition was
detected in the dorsal nucleus of the vagus nerve. Given the
biochemical and pathological similarities with sporadic CJD
(sCJD) cases linked to type-2 PrPSc (9) and methioninevaline
(MV) polymorphism at codon 129 in the prion protein gene
(PRNP), these findings have prompted ongoing strain typing in
inbred mice. Although the present findings dictate caution, here
we show that a PrPSc type associated with sCJD and the
previously undescribed bovine PrPSc show convergent molecular
signatures.
Materials and Methods
Tissue Collection and Processing. Whole brains were collected from
four Friesian, three Bruna Alpina, and one Piemontese cattle
between 5 and 15 years old. All these animals were routinely
slaughtered and resulted positive to the statutory rapid TSE test
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations: TSE, transmissible spongiform encephalopathy, BSE, bovine
spongiform
encephalopathy; CJD, Creutzfeldt–Jakob disease; vCJD, variant CJD; sCJD,
sporadic CJD; PrP,
prion protein, PrPSc pathological PrP; BASE, bovine amyloidotic
spongiform encephalopathy.
†C.C. and G.Z. contributed equally to this work.
To whom correspondence should be addressed. E-mail:
salvatore.monaco@mail.univr.it.
© 2004 by The National Academy of Sciences of the USA
www.pnas.orgcgidoi10.1073pnas.0305777101 PNAS March 2, 2004 vol.
101 no. 9 3065–3070
MEDICAL SCIENCES
(Prionics, Zurich), which is based on the immunobiochemical
detection of bovine PrPSc in brain samples. Brains were longitudinally
cut into two halves; the left hemibrain was frozen and
stored at 80°C until biochemical studies, whereas the right part
was fixed in 10% buffered formaldehyde solution and dissected
in 5-mm-thick sections that were embedded in paraffin after
decontamination with 96% formic acid for 1 h. The paraffinembedded
blocks selected for the study included coronal sections
at the level of the olfactory bulb, the frontal, parietal, and
occipital cortices, the pyriform lobus, hippocampus, striatum,
thalamus, brainstem, and sagittal sections through the cerebellum.
Brains were also obtained from three routinely slaughtered
cattle free of neurological disorders. Tissues from patients with
CJD were obtained as described (15).
Bovine PrP Gene Determination. Genomic DNA was isolated from
frozen brain tissues by using a QIAamp DNA Mini Kit (Qiagen).
PCR amplification of the PrP gene was performed in 50-l
reaction volumes containing 0.5–1 g of genomic DNA, 25 mM
TrisHCl at pH 8.7, 200 M each dNTP, 1.5 mM MgCl2, 1 unit
of Taq DNA polymerase, and 1 M each primer, modified p78
() (5-TAAGTGGGCATATGATGCTC-3) and p9 () (5-
CTGGGATTCTCTCTGGTACT-3), according to previously
described procedures (16). Amplification reactions were performed
in a Gene Amp PCR system 9700 (Applied Biosystems)
for 41 cycles of 1 min at 94°C, 1.5 min at 56°C, and 1 min at 72°C.
PrP polymorphisms were detected by DNA sequencing on both
strands of the PCR products in an ABI 310 capillary system
(Applied Biosystems). To determine the number of copies of the
octapeptide repeats, PCR was carried out by using as primers
modified p78 () and p60 () (5-GATAGTAACGGTCCTCATAG-
3). PCR amplification products were examined in
ethidium bromide-stained 3% agarose gels.
Neuropathology and PrP Immunohistochemistry. Histological sections
obtained from each sampled specimen were deparaffinized,
rehydrated, and stained with hematoxylin and eosin for
evaluation of pathological changes; additional sections were
stained with thioflavin-S. For the immunohistochemical study,
after rehydration, sections were treated with 96% formic acid for
20 min at room temperature, followed by autoclaving at 121°C
for 30 min. After rinsing, sections were incubated overnight at
4°C with anti-PrP monoclonal antibody F9997.6.1 (17) diluted
to 11,000. Subsequent antibody detection was carried out by
using a biotinylated goat anti-mouse secondary antibody diluted
to 1200 for 20 min (Vector Laboratories, Burlingame, CA) at
room temperature, followed by the avidin-biotin-peroxidase
complex (Vectastain ABC kit, Vector Laboratories) according
to manufacturer’s protocol. Immunoreactivity was visualized by
using 3,3-diaminobenzidine as chromogen.
For electron microscopic study, formalin-fixed specimens of
brain tissues were extensively washed in PBS, fixed in 2.5%
glutaraldehyde in 0.1Msodium cacodylate buffer, and postfixed
with 2% osmium tetroxide for 2 h. After dehydration in graded
acetone solutions, tissues were embedded in Spurr’s resin.
Subsequently, the sections were prepared for electron microscopy
and observed with a Zeiss EM 109 electron microscope.
Immunoblot Analysis. From each central nervous system sample,
100 mg of tissue was homogenized in 9 vol of lysis buffer (100
mM sodium chloride10 mM EDTA0.5% Nonidet P-400.5%
sodium deoxycholate10 mM TrisHCl, pH 7.4) and digested
with 50 gml proteinase K (Boehringer Mannheim) for 1 h at
37°C. Digestion was blocked by the addition of phenylmethylsulfonyl
fluoride at 2 mM. For deglycosylation, proteinase
K-digested samples were deglycosylated with recombinant peptide
N-glycosidase F (PNGase F) according to the supplier’s
instructions (Boehringer Mannheim). Samples, equivalent to 400
g of wet tissue, were resolved by electrophoresis on 13%
polyacrylamide gels and then transferred onto PVDF membrane
(Immobilon P; Millipore) for 2 h at 60 V. Membranes were
blocked with 1% nonfat dry milk in TBST (10 mM TrisHCl150
mMsodium chloride0.1% Tween 20, pH 7.5) for 1 h at 37°C and
incubated overnight at 4°C with anti-PrP monoclonal antibody
6H4 (Prionics) diluted to 15,000. Blots were developed by using
the Amersham Pharmacia enhanced chemiluminescence (ECL)
system, as described by the supplier and visualized on an
autoradiography film. Films were scanned by using a densitometer
(GS-710; Bio-Rad). The relative amounts of PrPSc distribution
were calculated as previously described (18).
Results
Genetic Analysis. In four cattle a silent mutation at codon 70
(CAG 3 CAA) was found. As to the number of octapeptide
repeats, a common cattle polymorphism, five animals were
homozygous for PrP genotype with six copies and one for
seven copies, whereas two Bruna Alpina cattle were heterozygous,
having fiveseven and sixseven repeats, respectively.
Genetic, pathological and biochemical findings are summarized
in Table 1.
Neuropathology and Immunohistochemistry.Although the presence
of early autolysis precluded an accurate pathological assessment
in some brain areas, in all animals spongiosis was not consistently
found in the brainstem, at the level of the obex or in more rostral
areas. The frontal, parietal, and occipital cortices were apparently
spared, and no vacuolation was detected in the olfactory
bulb, piriform cortex, and hippocampus. Mild spongiform
changes of the neuropil were observed only in two Friesian cattle
at the level of the thalamus. However, after PrP immunohisto-
Table 1. Epidemiological, neuropathological, and biochemical findings in
examined cattle
Code Breed Age, yr
Alleles,
octapeptide
repeats Genetic variation
PrP-amyloid
plaques
Prevailing
PrPSc glycoform
on Western blot
1088 Piemontese 15 66 Wild type Low molecular mass
109655 Bruna Alpina 5 57 Wild type 0 High molecular mass
102417 Friesian 9 66 Wild type 0 High molecular mass
141387 Bruna Alpina 11 67 Codon 70 CAGCAA, encodes QQ Low molecular
mass
78437 Bruna Alpina 5 77 Codon 70 CAACAA, encodes QQ 0 High molecular mass
16193 Friesian 5 66 Codon 70 CAGCAA, encodes QQ 0 High molecular mass
128204 Friesian 7 66 Wild type 0 High molecular mass
72797 Friesian 8 66 Codon 70 CAGCAA, encodes QQ 0 High molecular mass
The presence of amyloid plaques was assessed after thioflavin-S
staining, PrP immunohistochemistry, and ultrastructural examination.
Codon 70 in control cattle and other affected animals was CAGCAG,
encoding QQ.
3066 www.pnas.orgcgidoi10.1073pnas.0305777101 Casalone et al.
chemistry, two groups of animals were readily distinguished,
because of striking differences in patterns and topography of PrP
deposition (Fig. 1). Group 1, comprising six Friesian and Bruna
Alpina cattle, including the two cases with thalamic spongiosis,
matched the typical phenotype of BSE, characterized by the
occurrence of PrP deposits of granular type (in the neuronal
cytoplasm or in gray matter neuropil), linear type (thick, threadlike
profiles), and glial type, which confers a star-like appearance
(Fig. 1 a, c, e, and g). By contrast, group 2, one each Piemontese
and Bruna Alpina cattle 15 and 11 years old, respectively, was
characterized by the presence of PrP-amyloid plaque-like deposits,
kuru-like plaques, and granular extracellular and glial
deposits (Fig. 1 b, d, f, and h). The kuru-like plaques appeared
as dense unicentric (Fig. 2a), or less frequently multicentric,
round structures up to 25 m in diameter (Fig. 2b), with a pale
core and a dark radial periphery. PrP-positive plaques were also
fluorescent after thioflavin-S and were ultrastructurally composed
of bundles of straight, unbranched fibrils with a diameter
of 7 nm (Fig. 2 c and d). The two groups of cattle also showed
remarkable differences in brain regional distribution of PrP
deposits. In group 1, large amounts of granular PrP deposits were
observed in brainstem (Fig. 1a) and thalamus (Fig. 1c), whereas
the lobus piriformis (Fig. 1e), the olfactory bulb (Fig. 1g), and
cerebral cortexes were less involved. By contrast, the brainstem
showed only a weak PrP positivity in group 2, and the dorsal
motor nucleus of the vagus was unstained (Fig. 1b); PrP-amyloid
Fig. 1. PrP deposition in the brains of group 1 and group 2 cattle.
Immunohistochemistry showing the glial and granular patterns of PrP
deposition observed
in the dorsal nucleus of vagus nerve (a, 210), thalamus (c, 210),
pyriform cortex (e, 220), and olfactory bulb (g, 150) of an animal
representative of group
1. In group 2 cattle, the dorsal nucleus of the vagus nerve is unstained
(b, 210), whereas PrP-positive plaques are observed in the thalamus
(d, 210), pyriform
cortex ( f, 210), and olfactory bulb (h, 80).
Casalone et al. PNAS March 2, 2004 vol. 101 no. 9 3067
MEDICAL SCIENCES
plaques were seen in the thalamus (Fig. 1d), subcortical white
matter and deeper layers of cerebral cortexes (Fig. 1f ), and
olfactory bulb (Fig. 1h). Finally, the molecular layer of the
cerebellum exhibited PrP deposits of the glial type in group 1,
whereas some amyloid plaques were observed in group 2.
Biochemical Characterization and Regional Distribution of PrPSc.
Western immunoblots of proteinase K-treated brain homogenates,
obtained from different cortical and subcortical regions of
group 1 and group 2 animals, showed the presence of two distinct
PrPSc types, which were distinguishable on the basis of the
molecular mass of their unglycosylated fragments and the ratio
of differently glycosylated forms. The typical molecular ‘‘BSE
signature,’’ characterized by overrepresentation of the high
molecular mass glycoform, was detected in group 1 animals (Fig.
3a, odd lanes). In contrast, the Piemontese and Bruna Alpina
cattle (group 2) showed a predominance of the low molecular
mass glycoform and a protease-resistant fragment with a faster
electrophoretic mobility (Fig. 3a, even lanes).
In prion diseases, distinct PrPSc types usually result in different
patterns of deposition and brain regional distribution of the
abnormal protein. In group 1 animals, the highest amounts of
PrPSc were recovered, as expected, in the brainstem, hypothalamus,
and thalamus, and very low PrPSc levels were found in the
olfactory bulb and pyriform cortex (Fig. 3b). Conversely, the
distribution of PrPSc in group 2 cattle was more widespread than
in typical BSE cases, and the largest amounts of PrPSc were
detected in the thalamus, olfactory bulb, hippocampus, and
olfactory cortex, whereas lower PrPSc levels were recovered in
the brainstem (Fig. 3c). On the basis of the neuropathological
phenotype and the PrPSc distribution and glycotype, group 2
cattle were reminiscent of the sCJD phenotype seen in subjects
with MV at PRNP codon 129 and type 2 PrPSc (MV2) (9, 19).
Therefore, we compared proteinase K-treated brain homogenates
from group 1 and group 2 cattle with sCJD with different
molecular types of PrPSc, either homozygous or heterozygous at
PRNP codon 129. Remarkably, the PrPSc type detected in
TSE-affected cattle from group 2 had fragment size (Fig. 4a) and
glycoform ratios (Fig. 4b) similar to a PrPSc type encountered in
sCJD MV2 (9, 19).
Discussion
In natural and experimental TSEs, PrPSc deposition represents
an early event that occurs weeks to months before the development
of spongiform changes (20, 21). As a consequence, the
detection of PrPSc by Western immunoblot provides a unique
opportunity in the diagnosis of BSE early in the incubation
period and, therefore, in presymptomatic animals. The identification
of the present cattle by postmortem biochemical tests, in
the absence of clear neurological involvement, suggests that the
disorder was detected at early stages, and this may also explain
the lack of widespread vacuolar changes.
Previous pathological studies in clinically suspect cases of BSE
in Great Britain have provided evidence for a uniform pattern
in the severity and distribution of vacuolar lesions in affected
animals, with medulla oblongata nuclei being the most involved
(22). While confirming that the BSE epidemic has been sustained
by a single agent, these studies have assessed the validity
of statutory criteria for the diagnosis of BSE, which is currently
based on both histopathological and immunobiochemical exam-
Fig. 2. PrP-positive amyloid plaques in group 2 animals. PrP-immunostaining
of the pyriform cortex from group 2 cattle, showing the presence of
kuru-like
amyloid plaques (a and b, 450). At ultrastructural examination amyloid
deposits are composed of aggregates and bundles of unbranched fibrils (c,
12,550; d, 60,000).
Fig. 3. Biochemical analysis and regional distribution of PrPSc in group
1 and
group 2 cattle. (a) Immunoblot with 6H4 monoclonal antibody of proteinase
K-treated brain homogenates from the thalamus of group 1 (odd lanes) and
group 2 animals (even lanes), before (lanes 1–4) and after (lanes 5–8)
enzymatic
deglycosylation. (b and c) Regional distribution of brain PrPSc in group
1 (b) and group 2 (c) cattle; values of PrPSc are reported below each
gel as the
percentage of the highest value obtained. Molecular size markers are shown
on the right as Mr 103.
3068 www.pnas.orgcgidoi10.1073pnas.0305777101 Casalone et al.
ination of the medulla. However, the prevailing involvement of
cortical regions in the cattle with amyloid deposition suggests
that postmortem brain sampling should not be limited to the
obex. In addition, a careful analysis of PrPSc glycoform profiles
at the confirmatory Western immunoblot may provide a molecular
means of identifying atypical cases of bovine TSE.
Bovine Amyloidotic Spongiform Encephalopathy (BASE): A Second
Bovine TSE. The present findings show that a previously undescribed
pathological and immunohistochemical phenotype, associated
with cattle TSE, is related to the presence of a PrPSc type
with biochemical properties, including the gel mobility of the
protease-resistant fragment and glycoform ratios, different from
those encountered in cattle BSE. Brain deposition of this
pathological isoform of cattle PrP correlates with the formation
of PrP-amyloid plaques, as opposed to typical BSE cases. Although
in several natural and experimental recipients of the
BSE agent, including humans (13), neuropathological changes
are characterized by the presence of PrP-positive amyloid
deposits with surrounding vacuolation, cattle BSE is not associated
with PrP-amyloid plaque formation. On the basis of the
above features, we propose to name the disease described here
BASE. Although observed in only two cattle, the BASE phenotype
could be more common than expected. In previous
studies, amyloid congophilic plaques were found in 1 of 20 BSE
cases examined systematically for amyloid (23), and it was reported
that focal cerebral amyloidosis is present in a small proportion of
BSE cases (24). Although no biochemical analysis of PrPSc glycotype
is available for these animals with ‘‘atypical BSE phenotype,’’
our present results underscore the importance of performing
a strain-typing in bovine TSE with amyloid deposition.
In sCJD, the neuropathological phenotype largely correlates
with the molecular type of PrPSc and distinct polymorphic sites
of PRNP (9, 19). This is in contrast with the situation in cattle,
where different genotypes have been reported based on the
variable numbers of octapeptide repeats in each allele, but no
evidence for single-codon polymorphisms in the PrP gene has
been established (25, 26). Because the present animals shared a
similar genetic background and breed, differences in disease
phenotypes between cattle with BSE and BASE can be tentatively
related only to distinct PrPSc types or alternative routes of
infection and spread of prion pathology. Accordingly, the lack of
involvement of the motor dorsal nucleus of the vagus and the
slight involvement of the brainstem in BASE, suggests a route for
spreading of the agent other than the alimentary tract. Therefore,
unless the BASE agent propagates throughout the olfactory
pathway or other peripheral routes, it is possible that this
disorder represents a sporadic form of cattle TSE, which would
also explain the difference in ages between the two groups of
affected animals.
Phenotypic Similarities Between BASE and sCJD. The transmissibility
of CJD brains was initially demonstrated in primates (27), and
classification of atypical cases as CJD was based on this property
(28). To date, no systematic studies of strain typing in sCJD have
been provided, and classification of different subtypes is based
on clinical, neuropathological, and molecular features (the polymorphic
PRNP codon 129 and the PrPSc glycotype) (8, 9, 15, 19).
The importance of molecular PrPSc characterization in assessing
the identity of TSE strains is underscored by several studies,
showing that the stability of given disease-specific PrPSc types is
maintained upon experimental propagation of sCJD, familial
CJD, and vCJD isolates in transgenic PrP-humanized mice (8,
29). Similarly, biochemical properties of BSE- and vCJDassociated
PrPSc molecules remain stable after passage to mice
expressing bovine PrP (30). Recently, however, it has been
reported that PrP-humanized mice inoculated with BSE tissues
may also propagate a distinctive PrPSc type, with a ‘‘monoglycosylated-
dominant’’ pattern and electrophoretic mobility of the
unglycosylated fragment slower than that of vCJD and BSE (31).
Strikingly, this PrPSc type shares its molecular properties with the
a PrPSc molecule found in classical sCJD. This observation is at
variance with the PrPSc type found in MV2 sCJD cases and in
cattle BASE, showing a monoglycosylated-dominant pattern but
faster electrophoretic mobility of the protease-resistant fragment
as compared with BSE. In addition to molecular properties
of PrPSc, BASE and MV2 sCJD share a distinctive pattern of
intracerebral PrP deposition, which occurs as plaque-like and
amyloid-kuru plaques. Differences were, however, observed in
the regional distribution of PrPSc. While inMV2 sCJD cases the
largest amounts of PrPSc were detected in the cerebellum,
brainstem, and striatum, in cattle BASE these areas were less
involved and the highest levels of PrPSc were recovered from the
thalamus and olfactory regions.
In conclusion, decoding the biochemical PrPSc signature of
individual human and animal TSE strains may allow the identification
of potential risk factors for human disorders with
unknown etiology, such as sCJD. However, although BASE and
sCJD share several characteristics, caution is dictated in assessing
a link between conditions affecting two different mammalian
species, based on convergent biochemical properties of diseaseassociated
PrPSc types. Strains of TSE agents may be better
characterized upon passage to transgenic mice. In the interim
until this is accomplished, our present findings suggest a strict
epidemiological surveillance of cattle TSE and sCJD based on
molecular criteria.
We are grateful to Giuseppe Ru (Centro di Referenza Nazionale per le
Encefalopatie Animali, Istituto Zooprofilattico Sperimentale di Torino)
for the provision of surveillance data. We also thank Diana Bazan for
preparing material for transmission electron microscopy, and Ines
Fig. 4. Electrophoretic analysis of PrPSc in cattle TSE and sCJD. (a)
Western
blot detection of PrPSc in brains of group 1 animals (lanes 1 and 5);
subject with
sCJD and type 1 PrPSc, methioninemethionine at codon 129 (lane 2); subject
with sCJD and type 2 PrPSc, methioninevaline at codon 129 (lane 3); and
group
2 cattle (lane 4). (b) Relative proportions of the three PrPSc
glycoforms in group
1 and group 2 cattle compared with glycoform profiles obtained in nine sCJD
patients, methioninevaline at codon 129 and with type 2 PrPSc. Mean
standard deviation is shown. Upper band, diglycosylated form; middle band,
monoglycosylated form; and lower band, unglycosylated form.
Casalone et al. PNAS March 2, 2004 vol. 101 no. 9 3069
MEDICAL SCIENCES
Crescio, Cristiano Corona, Cristiano Longo, Michele Fiorini, Alessia
Farinazzo, and Matteo Gelati for technical assistance. This work was
supported by a grant from the Italian Ministry of Health (IZS PLV
00401 to M.C. and S.M.), a grant from Fondazione Cariverona (2002-
Malattie neurodegenerative to S.M.), and in part by the Italian Ministry
of Health (RF 2001.96 to F.T.).
1. Prusiner, S. B. (1998) Proc. Natl. Acad. Sci. USA 95, 13363–13383.
2. Collinge, J. (2001) Annu. Rev. Neurosci 24, 519–550.
3. Parchi, P. & Gambetti, P. (1995) Curr. Opin. Neurol. 8, 286–293.
4. Brown, P., Goldfarb, L. G. & Gajdusek, D. C. (1991) Lancet 337,
1019–1022.
5. Prusiner, S. B. (1992) Biochemistry 31, 12277–12288.
6. Bessen, R. A. & Marsh, R. F. (1992) J. Virol. 66, 2096–2101.
7. Bessen, R. A. & Marsh, R. F. (1994) J. Virol. 68, 7859–7868.
8. Collinge, J., Sidle, K. C. L., Meads, J., Ironside, J. & Hill, A. F.
(1996) Nature
383, 685–690.
9. Parchi, P., Castellani, R., Capellari, S., Ghetti, B., Young, K.,
Chen, S. G.,
Farlow, M., Dickson, D. W., Sima, A., Trojanowski, J. Q., et al. (1996) Ann.
Neurol. 39, 767–778.
10. Hill, A. F, Sidle, K. C. L., Joiner, S., Keyes, P., Martin, T. C.,
Dawson, M. &
Collinge, J. (1998) Neurosci. Lett. 255, 159–162.
11. Gajdusek, D. C. (1977) Science 197, 943–960.
12. Brown, P., Preece, M. A. & Will, R. G. (1992) Lancet 340, 24–27.
13. Will, R. G., Ironside, J. W., Zeidler, M., Cousens, S. N.,
Estibeiro, K.,
Alperovitch, A., Poser, S., Pocchiari, M., Hofman, A. & Smith, P. G. (1996)
Lancet 347, 921–925.
14. Bruce, M. E., Will, R. G., Ironside, J. W., McConnel, I., Drummond,
D., Suttle,
A., McCardle, L., Chree, A., Hope, J., Birkett, C., et al. (1997) Nature
389,
498–501.
15. Zanusso, G., Farinazzo, A., Fiorini, M., Gelati, M., Castagna, A.,
Rigetti, P. G.,
Rizzuto, N. & Monaco, S. (2001) J. Biol. Chem. 276, 40377–40380.
16. Belt, B. G. M., Muileman, I. H., Schreuder, B. E. C., Bos-de
Ruijter, J.,
Gielkens, A. L. J., Smits, M. A. (1995) J. Gen. Virol. 76, 509–517.
17. O’Rourke, K. I., Baszler, T. V., Besser, T. E., Miller, J. M.,
Cutlip, R. C., Wells,
G. A., Ryder, S. J., Parish, S. M., Hamir, A. N., Cockett, N. E., et al.
(2000)
J. Clin. Microbiol. 38, 3254–3259.
18. Zanusso, G., Ferrari, S., Cardone, F., Zampieri, P., Gelati, M.,
Fiorini, M.,
Farinazzo, A., Gardiman, M., Cavallaro, T., Bentivoglio, M., et al. (2003)
N. Engl. J. Med. 348, 711–719.
19. Parchi, P., Giese, A., Capellari, S., Brown, P., Schulz-Schaeffer,
W., Windl, O.,
Zerr, I., Budka, H., Kopp, N., Piccardo, P., et al. (1999) Ann. Neurol. 46,
224–233.
20. Castellani, R., Parchi, P., Stahl, J., Capellari, S., Cohen, M. &
Gambetti, P.
(1996) Neurology 46, 1690–1693.
21. DeArmond, S. J. & Prusiner, S. B. (1995) Am. J. Pathol. 146, 785–811.
22. Simmons, M. M., Harris, P., Jeffrey, M., Meek, S. C., Blamire, I. W.
H.&Wells,
G. A. H. (1996) Vet. Rec. 138, 175–177.
23. Wells, G. A. H. & Wilesmith, J. W. (1995) Brain Pathol. 5, 91–103 .
24. Wells, G. A. H., Wilesmith, J. W., McGill, I. S. (1991) Brain
Pathol. 1, 69–78.
25. Goldmann, W., Hunter, N., Martin, T., Dawson, M. & Hope, J. (1991)
J. Gen.
Virol. 72, 201–204.
26. Hunter, N., Goldmann, W., Smith, G.&Hope, J. (1994) Vet. Rec. 135,
400–403.
27. Gibbs, C. J., Jr., Gajdusek, D. C., Asher, D. M., Alpers, M. P.,
Beck, E., Daniel,
P. M. & Matthews, W. B. (1968) Science 161, 388–389.
28. Brown, P., Rodgers-Johnson, P., Cathala, F., Gibbs, C. J., Jr. &
Gajdusek, D. C.
(1984) Ann. Neurol. 16, 295–304.
29. Korth, C., Kaneko, K., Groth, D., Heye, N., Telling, G., Mastrianni,
J., Parchi,
P., Gambetti, P., Will, R., Ironside, J., et al. (2003) Proc. Natl.
Acad. Sci. USA
100, 4784–4789.
30. Scott, M. R., Will, R., Ironside, J., Nguyen, H.-O. B., Tremblay,
P., DeArmond,
S. J. & Prusiner, S. B. (1999) Proc. Natl. Acad. Sci. USA 96, 15137–15142.
31. Asante, E. A., Linehan, J. M., Debruslais, M., Joiner, S., Gowland,
I., Wood,
A. L., Welch, J., Hill, A. F., Lloyd, S. E., Wadsworth, J. D. F. &
Collinge, J.
(2002) EMBO J. 21, 6358–6366.
3070 www.pnas.orgcgidoi10.1073pnas.0305777101 Casalone et al. 17 February 2004; Vol. 101, No. 7 URL: http://www.pnas.org/content/vol101/issue7/index.shtml?etoc Washington AP article Paul Brown states;
> Italian scientists discover new form of mad cow disease WASHINGTON
> (AP) 2/16/04
snip...
>Dr. Paul Brown of the National Institutes of Health said the finding
>does not indicate an increased threat to humans.
>
>If a new form of the disease were affecting humans there should be an
>increase in the incidence of CJD, said Brown, who was not part of the
>research team.
>
>However, scientists in Europe have studied all cases of sporadic CJD for
>the last decade and the incidence has not changed, said Brown, an expert
>in the disease, who works at the National Institute of Neurological
>Disease and Stroke.
what part of upward trend does Dr. Paul Brown not understand?
let us look at the _ upward trend_ of other sporadic CJD cases
in other BSE documented countries, some with atypical BSE;
Mouse model sheds new light on human prion disease
snip...
Professor John Collinge said We are not saying that all or even most
cases of sporadic CJD are as a result of BSE exposure, but some more
recent cases may be the incidence of sporadic CJD has shown an upward
trend in the UK over the last decade. While most of this apparent
increase may be because doctors are now more aware of CJD and better at
diagnosing it, serious consideration should be given to a proportion of
this rise being BSE-related. Switzerland, which has had a substantial
BSE epidemic, has noted a sharp recent increase in sporadic CJD.
snip... http://www.mrc.ac.uk/txt/index/public-interest/public-news-4/public-news_archive/public-news-archive_nov_dec_02/public-bse_and_sporadic_cjd.htm
from 1993 to 2002 France went from 35 to 108 sCJD cases. Italy went from
27 to 80 sCJD cases. Germany 21 to 102. besides the increase noted above
in both the UK and Switzerland by John Collinge;
http://www.eurocjd.ed.ac.uk/sporadic.htm The CDC has no idea of CJD/TSE in humans in the USA with the existing
TSE surveillance unit.
They have no CJD questionnaire that ask questions pertaining to route
and source...TSS
Asante/Collinge et al, that BSE transmission to the 129-methionine
genotype can lead to an alternate phenotype that is indistinguishable
from type 2 PrPSc, the commonest _sporadic_ CJD;
http://www.fda.gov/ohrms/dockets/ac/03/slides/3923s1_OPH.htm
Terry S. Singeltary Neurology Online, 27 Jan 2003
RE-Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob disease in the United States 26 March 2003 Next Post-Publication Peer Review Top Terry S. Singeltary, retired (medically) CJD WATCH
Send Post-Publication Peer Review to journal:
Re: RE-Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob disease in the United States
Email Terry S. Singeltary:
flounder@wt.net
I lost my mother to hvCJD (Heidenhain Variant CJD). I would like to
comment on the CDC's attempts to monitor the occurrence of emerging forms of CJD. Asante, Collinge et al [1] have reported that BSE transmission to the 129-methionine genotype can lead to an alternate phenotype that is indistinguishable from type 2 PrPSc, the commonest sporadic CJD. However, CJD and all human TSEs are not reportable nationally. CJD and all human TSEs must be made reportable in every state and internationally. I hope that the CDC does not continue to expect us to still believe that the 85%+ of all CJD cases which are sporadic are all spontaneous, without route/source. We have many TSEs in the USA in both animal and man. CWD in deer/elk is spreading rapidly and CWD does transmit to mink, ferret, cattle, and squirrel monkey by intracerebral inoculation. With the known incubation periods in other TSEs, oral transmission studies of CWD may take much longer. Every victim/family of CJD/TSEs should be asked about route and source of this agent. To prolong this will only spread the agent and needlessly expose others. In light of the findings of Asante and Collinge et al, there should be drastic measures to safeguard the medical and surgical arena from sporadic CJDs and all human TSEs. I only ponder how many sporadic CJDs in the USA are type 2 PrPSc?
http://www.neurology.org/cgi/eletters/60/2/176#535
Diagnosis and Reporting of Creutzfeldt-Jakob Disease Singeltary, Sr et
al. JAMA.2001; 285: 733-734. http://jama.ama-assn.org/cgi/content/full/285/6/733?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=dignosing+and+reporting+creutzfeldt+jakob+disease&searchid=1048865596978_1528&stored_search=&FIRSTINDEX=0&journalcode=jama
Tracking Spongiform Encephalopathies in North America (Lancet Infectious
Disease Volume 3, Number 8 01 August 2003)
http://infection.thelancet.com/journal/vol3/iss8/contents BRITISH MEDICAL JOURNAL BMJ http://www.bmj.com/cgi/eletters/319/7220/1312/b#EL2 BMJ http://www.bmj.com/cgi/eletters/320/7226/8/b#EL1 suppressed peer review of Harvard study October 31, 2002 http://www.fsis.usda.gov/oa/topics/BSE_Peer_Review.pdf Terry S. Singeltary Sr.
P.O. Box 42
Bacliff, Texas USA 77518 ########### http://mailhost.rz.uni-karlsruhe.de/warc/bse-l.html ############
Follow Ups:
Post a Followup
|
