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Flashcards in Prions Deck (18):
1

Prions are...

Infectious agent composed of a protein with an abnormal conformation

2

Prions cause

TSE - Transmissible Spongiform Encephalopathy

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Human Prion Diseases (TSEs) Include:

Kuru
Creutzfeldt-Jakob Disease (CJD)
Variant CJD
Gerstmann-Straussler-Scheinker (GSS) Syndrome
Fatal familial insomnia
Sporadic fatal Insomnia

4

Animal Prion Diseases (TSEs) Include:

Scrapie (Sheeps and goats)
Transmissible mink encephalopathy
Bovine spongiform encephalopathy (BSE(Mad Cow Disease))
Chronic Wasting Disease (mule, deer, elk)

5

Kuru

1950s, Fore people ofof Papua New Guinea, !% Incidence, Tremor, Muscular incapacity, dementia, death within 1 year

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Differences compared to Classic Viruses

No Defined morphology
Cannot be disinfected
No Cytopathological effect
No Immune response
No Interferon production
No Inflammatory Response

7

PrPC

Cellular Prion Protein
207 amino acid protein encoded by human chromosome 20
Found on Neurons, Lymphocytes, Follicular DCs, interacts and modulates some membrane proteins in brain: Copper shuttling, Pottasium channels, Neural cell adhesion molecule

8

PrPSC

Abnormal Post-translational converted Isoform of PrPC.
Contains more Beta Sheets

9

PrPC to PrPSC

Aggregation

10

Differences of PrPSC

multimeric
Protease Resistant
Forms Fibrils
Exists outside Cell
Long Turnover

11

Pathogenesis

-No cytopathologic effect
-long doubling time & incubation
-Cause vacuolation of neurons (Spongiform), Plaques, gliosis
-Cause loss of muscle control, shivering, tremors, dementia
-Lack of antigenicity
-Lack of inflammation
-Lack of immune response

12

Transmission

Infected Tissue
Inherited
Random Occurrence

13

Treatment

No Treatment
(dont eat human brain)

14

Clinical Syndromes of CJD

Long incubation period (1-30 years)
Rapid progression to death after onset of symptoms (~8 months)
Loss of Muscle Control
Shivering
Myoclonic jerks and tremors (random jerks, experienced by everyone)
Loss of coordination
Rapidly progressive dementia
DEATH

15

Diagnosis

No methods for detecting Prions
No serologic response
Based on clinical symptoms
Confirmation by MRI
Real confirmation at autopsy (amyloid plaques, spongiform vacuoles, Protein-misfolding cyclic assay)

16

Mad Cow Disease (BSE)

emerged in 1980s England
Feeding Cattle meat and bone meal
First infected human in 1994, resulting in vCDJ
UK killed a bunch of cows

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Mad Cow Disease (BSE) in Canada

1 Cow confirmed in 2003
slaughtered 2700 cows to prevent spread

18

Chronic Wasting disease

Deer, elk, moose
in parts of USA and SK, AB
brain lesions, emaciated, listless and droopy ears, salivate excessively, die