CA2205179A1 - Spongiform encephalopathy detection methods - Google Patents

Spongiform encephalopathy detection methods

Info

Publication number
CA2205179A1
CA2205179A1 CA002205179A CA2205179A CA2205179A1 CA 2205179 A1 CA2205179 A1 CA 2205179A1 CA 002205179 A CA002205179 A CA 002205179A CA 2205179 A CA2205179 A CA 2205179A CA 2205179 A1 CA2205179 A1 CA 2205179A1
Authority
CA
Canada
Prior art keywords
apolipoprotein
animal
amount
spongiform encephalopathy
agent
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
CA002205179A
Other languages
French (fr)
Inventor
Paula Keyes
Michael Dawson
Trevor Conrad Martin
Verity Jones
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Minister of Agriculture Fisheries and Food UK
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB9424015A external-priority patent/GB9424015D0/en
Application filed by Individual filed Critical Individual
Publication of CA2205179A1 publication Critical patent/CA2205179A1/en
Abandoned legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/53Immunoassay; Biospecific binding assay; Materials therefor
    • G01N33/569Immunoassay; Biospecific binding assay; Materials therefor for microorganisms, e.g. protozoa, bacteria, viruses
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/53Immunoassay; Biospecific binding assay; Materials therefor
    • G01N33/569Immunoassay; Biospecific binding assay; Materials therefor for microorganisms, e.g. protozoa, bacteria, viruses
    • G01N33/56983Viruses
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/68Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids
    • G01N33/6893Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids related to diseases not provided for elsewhere
    • G01N33/6896Neurological disorders, e.g. Alzheimer's disease
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2800/00Detection or diagnosis of diseases
    • G01N2800/28Neurological disorders
    • G01N2800/2814Dementia; Cognitive disorders
    • G01N2800/2828Prion diseases

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Immunology (AREA)
  • Biomedical Technology (AREA)
  • Hematology (AREA)
  • Chemical & Material Sciences (AREA)
  • Urology & Nephrology (AREA)
  • Molecular Biology (AREA)
  • Analytical Chemistry (AREA)
  • Pathology (AREA)
  • Microbiology (AREA)
  • Biotechnology (AREA)
  • Virology (AREA)
  • Cell Biology (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Tropical Medicine & Parasitology (AREA)
  • Neurosurgery (AREA)
  • Neurology (AREA)
  • Proteomics, Peptides & Aminoacids (AREA)
  • Investigating Or Analysing Biological Materials (AREA)
  • Peptides Or Proteins (AREA)

Abstract

A method for detecting the presence of spongiform encephalopathy in an animal comprising determining the presence and/or amount of agent (e.g. by the use of 2DPAGE, followed by staining and densitometry readings of the stained agent) in a body fluid (e.g. cerebrospinal fluid) of test animal which cross-reacts with antibody raised against apoliprotein E, and has a molecular weight of between 34 and 38 kDa and a pI of between 5.4 and 5.7 comparing the concentration with a control value, and correlating the relationship between the two with the likely presence of spongiform encephalopathy in the animal.

Description

SPONGI~O.~. EN~FPHALOPATHY DETECTION r~l~ODS

The present invention relates to methods for the detection of spongiform encephalopathies in animals, and in particular for the detection of bovine spongiform encephalopathy (BSE) in cattle.
.

Spongiform encephalopathies are a group of diseases which include scrapie in sheep and Creutzfeldt-Jakob disease (CJD) in humans.

BSE is a notifiable fatal neurodegenerative disease found in cattle.
BSE is of major importance to the British farming industry.

Currently cases of BSE are identified by clinical manifestations in the animal. Cases are confirmed by post-mortem analysis of brain tissue, for instance by histopathology, by detection of scrapie associated fibrils or proteinase K resistant protein.

These methods have the disadvantage that they necessitate the slaughter of potentially-infected animals which may turn out to be disease-free. Alternatively, clinical signs may be absent or go undetected, thus leaving infected animals in the herd.

Harrington et ~1 (New England Journal of Medicine (1986) Vol 315, No 5, pp 279-283) used high resolution two dimensional polyacrylamide gel electrophoresis (2DPAGE) to discover the presence of 4 abnormal proteins in the cerobrospinal fluid of human patients suffering from CJD. However, the precise identity of these proteins was not ascertained.

Thus there exists a need for a pre-mortem test for spongiform encephalopathies which can be used when diagnosing potentially-infected animals.

The present invention has now provided a method for detecting spongiform encephalopathies in animals which addresses some, and in preferred forms all, of these problems.

According to one aspect of the present invention there is provided method for detecting the presence of spongiform encephalopathy in an animal comprising determining the presence and/or amount of agent in a body fluid of the animal which cross-reacts with antibody raised against apoliprotein E, and relating the result of this determination to the infection status of the animal.

~referably the result of the determination is compared with a control value, and the relationship between the two is correlated with the infection status of the animal.

Preferably the method is used to detect BSE.

Apolipoprotein E is a cholesterol transporting protein produced in the peripheral and central nervous system. Its presence in either multiple- or single-forms has been categorised in cerebrospinal fluid (CSF) and serum.

Thus the discovery that spongiform encephalopathy infection in an animal can be correlated with the presence of, or an increase in the concentration of, an agent or agents in the body fluids of that animal, forms the basis for the methods of the current invention.

The agent or agents are cross reactive with anti-apolipoprotein E, have a molecular weight of around 34-38 kDa, and have a pI of around 5.4 - 5.7. This is consistent with their identification as apolipoprotein E, and the term 'Apo E agent' as used hereinafter is intended to embrace any agent which has these properties (including apolipoprotein E itself and isoforms or multiple-forms thereof).

It should be noted that there is no requirement to accurately quantify the Apo E agent concentration because spongiform encephalopathy may be detected by comparison with a control.

The control value may be derived from the Apo E agent concentration in a different animal (for which the infection status is known) and which is analysed in parallel with the test animal. Alternatively, the control value may come from the same animal, or be a known standard.

The control value may be determined using the same method used for the test animal, or may be derived by a different analytical method.

The results from the 'control' animal may be used to derive a standard positive- or negative-control value, or to calibrate the test animal result.

Preferably the body fluid analysed in the method is CSF since authentic apolipoprotein E is the major apolipoprotein found in this fluid. Additionally, the proximity of the CSF to brain means that neurological disorders which produce alterations in the protein composition of the brain may be manifested in the CSF. Methods for extracting samples of CSF are well known to those skilled in the art.

The invention embraces any method for analysing the concentration of Apo E agent in a body fluid of an animal which is currently comprised in the art, and any methods which may later become available.

Preferably the presence and/or amount of Apo E agent in a body fluid of the animal is derived by the use of PAGE or 2DPAGE to separate out the Apo E agent from other agents in the body fluid, and then stAining the gel and making densitometry measurements in the region of the gel of interest in order to determine the presence and/or amount of the Apo E agent.

Preferably the identity of the Apo E agent ls confirmed by use of immunogenic material, for instance antibody raised against Apo E
agent or a synthetic peptide based on a sequence thereof. Suitable immunogen-based techniques for identifying the presence of cross-reactive agents are well known to those skilled in the art eg.
ELISA or Western Blotting.

In alternative embodiments of the invention, these immunogenic techniques may be used both to identify the Apo E agent, and also to estimate its concentration.

Thus the invention makes available methods for detecting the presence of spongiform encephalopathy in a test animal which address many, and in preferred forms all, of the problems of the prior art. The balance between test certainty and ease of use will be dependent on the precise method of Apo E agent analysis chosen for use in the methods of the current invention. However, the pre-mortem diagnosis of BSE in cattle opens up the possibility of mass-testing in herds, thereby reducing the likelihood of slaughtering uninfected ~ni~ls or 'missing' infected ones.

The methods of the present invention will now be described, by way of illustration only, through reference to the following example and figures. Other embodiments falling within the scope of the invention will occur to those skilled in the art in the light of this.

FXAMP!.F. - IDENTIFICATION OF BSE IN CATT!F

Sample preparation: CSF samples were collected from BSE-positive cattle and BSE-negative cattle. In each case the diagnosis was confirmed by post-mortem histopathology and electron microscopy. CSF
samples were taken by cisternamagna puncture after death and concentrated 10-15 fold. Volumes of CSF cont~ining 40 ,ug total protein were mixed in a 4:1 ratio with denaturing solution (lg sodium dodecyl sulphate (SDS) and 0.232g dithiothreitol in lOml water) and heated at 95C for 5 minutes. Samples were then pulse centrifuged.

Electrophoresis: The prepared samples were 2D electrophoresed using a Millipore Investigator 2D electrophoresis system according to the method in the instruction manual. First dimensional iso-electric-focussing was carried out in 26 cm threaded glass tubes with 1 mm inner diameter in a pH gradient of 3-10 for 18000 volt hours after pre-focussing the gels for 1 hour to 1500 V. Second dimension SDS-PAGE was carried out using 1 mm thick large format gels (23 cm x 23 cm) with 12.5% acrylamide and no stacking gel.

St~ining and Image analysis: The 2D gels were silver stained according to the Millipore manual. Gels were scanned with an 0 i ~ia scanner XRS and analysed using Bioimage software and Investigator Database programme (Millipore) using a sunSPARC station computer.

Confirmation of the identity of Apo E agent: The 2D gels were electroblotted onto Immobilon-P membranes overnight at 30V using a Bio-Rad Trans-Blot cell. The blots were blocked using Tween 80 for l hour and then incubated for 90 minutes with sheep antiserum cont~ining polyclonal antibody raised against authentic apolipoprotein E. Bound sheep antibodies were detected using rabbit anti-sheep IgG and a horseradish peroxidase detection system. A
number of agents in the region of interest (approximate molecular weight of 34-38 kDa, and a pI of around 5.4 - 5.7) were found to have cross reacted with anti-apolipoprotein E antibody.

Comparison of BSE-negative and BSE-positive cattle: A comparison of the stained gels from typical BSE-positive and -negative samples is shown in Fig l(a) and Fig l(b). As can be seen the number and intensity of the silver stained spots in the region corresponding to agents having an approximate molecular weight of 34-38 kDa, and a pI
of around 5.4 - 5.7 (labelled 'Apo E') is higher in the BSE-positive sample.

A comparison of the mean optical density of those silver-stained spots on the gels which were also found to cross react with anti-apolipoprotein E antibody is found below:

~g~ No BSE-negative BSE-Dositive 1 0.13 0.47 2 0.42 o.84 3 0.45 o.64 4 0.45 0.99 o.46 1.02 6 0.41 o.69 7 o.87 1.12 By comparing the two sets of optical density readings it can be seen that each agent is present in consistently higher amounts in the BSE-positive (n=31) animals than in the BSE-negative (n=27) Anir~lc, thus indicating that the presence and/or amount of these agents can be used to detect the likely presence of BSE in potentially infected Ani r~l !:; .

Claims (9)

1. A method for determining the spongiform encephalopathy disease status in an animal comprising:
a) determining the amount of apolipoprotein E in the cerebrospinal fluid of the animal, b) comparing the result of this determination with a control value, c) correlating an increased concentration of apolipoprotein E with a positive disease status of the animal.
2. A method as claimed in claim 1 wherein the spongiform encephalopathy is bovine spongiform encephalopathy.
3. A method as claimed in claim 1 or 2 wherein the amount of apolipoprotein E in the cerebrospinal fluid of the animal is determined by assessing the amount of agent in the cerebrospinal fluid of the animal which cross-reacts with antibody raised against apolipoprotein E.
4. A method as claimed in claim 1 or claim 2 wherein the amount of apolipoprotein E in the cerebrospinal fluid of the animal is determined by separating the apolipoprotein E from other materials in the fluid using polyacrylamide gel electrophoresis, staining the gel, identifying the apolipoprotein E, and estimating the amount of apolipoprotein E from the density of the staining.
5. A method as claimed in claim 4 wherein the amount of apolipoprotein E is determined by assessing the amount of agent in the cerebrospinal fluid having a molecular weight of between 34 and 38 kDa and a pI of between 5.4 and 5.7.
6. A method as claimed in claim 5 wherein the identity of the apolipoprotein E on the gel is confirmed by the use of antibody raised against apolipoprotein E.
7. A method as claimed in any one of claims 4 to 6 wherein the polyacrylamide gel electrophoresis is two-dimensional polyacrylamide gel electrophoresis.
8. A method as claimed in any one of the preceding claims wherein the control value is derived by the same method as that used with the animal but using a further animal known to be either spongiform encephalopathy-negative or -positive.
9. A method as claimed in any one of the preceding claims substantially as described hereinbefore with reference to the Example.
CA002205179A 1994-11-29 1995-11-28 Spongiform encephalopathy detection methods Abandoned CA2205179A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB9424015.7 1994-11-29
GB9424015A GB9424015D0 (en) 1994-11-29 1994-11-29 Spongiform encepmalopathy detection methods
GB9424769.9 1994-12-07
GBGB9424769.9A GB9424769D0 (en) 1994-11-29 1994-12-07 Spongiform encephalopathy detection methods

Publications (1)

Publication Number Publication Date
CA2205179A1 true CA2205179A1 (en) 1996-06-06

Family

ID=26306057

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002205179A Abandoned CA2205179A1 (en) 1994-11-29 1995-11-28 Spongiform encephalopathy detection methods

Country Status (11)

Country Link
EP (1) EP0795132A1 (en)
AU (1) AU3932895A (en)
CA (1) CA2205179A1 (en)
CZ (1) CZ164297A3 (en)
FI (1) FI972253A (en)
GB (1) GB2308659B (en)
HU (1) HUT77340A (en)
NO (1) NO972339D0 (en)
NZ (1) NZ295721A (en)
SK (1) SK67897A3 (en)
WO (1) WO1996017249A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998016834A1 (en) 1996-10-15 1998-04-23 Imperial College Of Science, Technology And Medicine Diagnosis of spongiform encephalopathy
GB2355074A (en) * 1996-10-15 2001-04-11 Imperial College Method for predicting susceptibility to bovine spongiform encephalopathy
GB9701045D0 (en) * 1997-01-18 1997-03-05 Narang Harash K Diagnosis of neuro-degenerative disorders
CA2286279C (en) * 1998-02-06 2009-05-12 Harash Kumar Narang Diagnosis of neuro-degenerative disorders
FR2827047B1 (en) * 2001-07-03 2003-09-26 Apoh Technollgies Sa PROCESS FOR SEPARATION AND / OR DETECTION AND / OR IDENTIFICATION AND / OR QUANTIFICATION OF PRION PROTEINS

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4892814A (en) * 1987-06-22 1990-01-09 The United States Of America As Represented By The Department Of Health And Human Services Method for distinguishing Creutzfeldt-Jakob disease from other dementias

Also Published As

Publication number Publication date
AU3932895A (en) 1996-06-19
HUT77340A (en) 1998-03-30
SK67897A3 (en) 2000-02-14
FI972253A (en) 1997-07-28
GB2308659B (en) 1998-11-18
NO972339L (en) 1997-05-22
GB2308659A (en) 1997-07-02
CZ164297A3 (en) 1997-11-12
EP0795132A1 (en) 1997-09-17
GB9708663D0 (en) 1997-06-18
NZ295721A (en) 1999-03-29
NO972339D0 (en) 1997-05-22
FI972253A0 (en) 1997-05-28
WO1996017249A1 (en) 1996-06-06

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FZDE Discontinued