Prions and retroviruses

Question 1

Proteinaceous infectious agents

Answer 1

prions

Question 2

Prions induce a conformational alteration of a normal ____ protein from what to what?

Answer 2

CNS protein

from alpha helix to beta pleated sheets

Question 3

Prions are _________ protein aggregates that cause extensive _________ of neurons and produce fatal degenerative CNS diseases called what?

Answer 3

insoluble
vacuolation
transmissible spongiform encephalophaties

Question 4

What does spongiform refer to?

Answer 4

Presence of multiple vacuoles that make the tissue look like a sponge

Question 5

What is the normal prion protein called? What is the infectious form called?

Answer 5

PrPc

PrPsc

Question 6

What are normal prion proteins?

Answer 6

Surface components of neurons and glial cells

Question 7

What makes prions so hard to eradicate?

Answer 7

Very resistant to inactivation

Question 8

Where was Kuru endemic to?
How did people get it?
How did it stop?

Answer 8

Papa New Guinea
Engaged in ritual cannibalism - ate the liver and brain of esteemed person
stopped when they stopped eating people

Question 9

Which is the rapid variant of TSE?

Answer 9

CJD

Question 10

What is the sheep TSE called? Why is it aptly named?

Answer 10

Scrapie

Infected sheep scrape along fences and walls

Question 11

What symptoms does kuru produce? How is it transmitted?

Answer 11

spasticity and ataxia - infectious

Extinct

Question 12

What symptoms does CJD produce? how is it transmitted/acquired?

Answer 12

dementia, spasticity, seizures

infectious or inherited

Question 13

What does most forms of human TSEs have in common in terms of symptomology?

Answer 13

Most have ataxia as a feature

Question 14

What is the enzyme that retroviruses must carry with them?

Answer 14

RNA dependent DNA polymerase or reverse transcriptase

Question 15

What is the central dogma of molecular biology?

Answer 15

DNA –> RNA –> protein

Question 16

How do retroviruses integrate their genome if they have RNA?

Answer 16

RNA –> reverse transcriptase –> dsDNA –> integrate into host genome

Question 17

When the DNA is integrated into the host genome, what is the retrovirus now called?

Answer 17

a provirus

Question 18

When the provirus chooses to replicate, how does it accomplish this?

Answer 18

Uses host RNA polymerase to synthesize mRNA to manufacture viral protein, synthesize reverse transcriptase and makes its genome (ssRNA)

Question 19

What are the two big families of retroviruses?

Answer 19

Oncoviruses

Lentiviruses

Question 20

HIV-like viruses infect many animals without causing disease - e.g. monkeys. In what animals does it cause disease?

Answer 20

Equines and house cats (and humans)

Question 21

From what was SIV first isolated?

Answer 21

Japanese macaques

Question 22

What are the three different SIV variants?

Answer 22

SIVgm - green monkeys
SIVcpz - chimpanzee
SIVsm - sooty mangabey

Question 23

Why do we believe that HIV came from chimps?

Answer 23

SIVcpz found in Gabon serologically reacts with HIV-1

Question 24

How do we believe that HIV entered the human population?

Answer 24

Entered human population through bush meat trade in Africa, then sexual transmission

Question 25

What did SIVcpz probably evolve into to infect humans?

Answer 25

HIV-1 and HIV-0

Question 26

Which SIV serotype has 80-90% homology with HIV-2?

Answer 26

SIVsm

Question 27

What is the approximate period of incubation of HIV?

Answer 27

10 years

Question 28

How is HIV-2 different from HIV-1?

Answer 28

Low lethality, mainly in West Africa and incubation period closer to 20 years

Question 29

How did HIV go from Africa to Europe?

Answer 29

Cameroon was originally a german colony. After WW2, this colony was forced to leave and go back to Germany (then Danzig - now Poland), brought HIV with them

Question 30

P. ________ is characteristic of AIDS.

Answer 30

P. jiroveci (used to be called P. carinii) | P = pneumocystic

Question 31

What ultimately led to the discovery of HIV?

Answer 31

Found a high order of pentamidine to treat PCP (P. cariini pneumonia) in young, gay males - also high rates of Karposi Sarcoma at the time - noticed they were immunosuppressed and termed cause as GRID (now HIV)

Question 32

What does GRID stand for?

Answer 32

Gay-related immune deficiency

Question 33

Where is HIV huge? What is it considered in terms of public health? What is a major issue for treatment?

Answer 33

West, east and south Africa Pandemic Affordability

Question 34

Soon after infection with HIV, what symptoms manifest? What is it associated with?

Answer 34

Flu-like illness which is associated with seroconversion

Question 35

What is seroconversion?

Answer 35

Period in which HIV antibodies are produced

Question 36

How many years does it take for immunosuppresion to develop?

Answer 36

years to decades

Question 37

What does HIV cause after a period of years?

Answer 37

CD4 cell depletion resulting in opportunistic infections and also dementia secondary to direct infection of CNS

Question 38

AIDS is reserved for who?

Answer 38

those with a CD4 count lower than 200 cells

Question 39

What is the normal range for CD4 cells?

Answer 39

1500-500

Question 40

Role of cofactors in accelerating the development of AIDS is controversial, but certain __________ appear to have roles.

Answer 40

mycoplasmas

Question 41

What are the different types of people infected with HIV?

Answer 41

non-progressers - infected with HIV but remain perfectly healthy rapid progressors - CD4 count depletion within shorter time frame (~3 years) HIV resistant - despite repeated exposure, no seroconversion

Question 42

Is it possible to completely eliminate HIV?

Answer 42

yes, with 50+ years of HAART

Question 43

What is the staple treatment for keeping HIV in check?

Answer 43

HAART - highly active anti-retroviral therapy

Question 44

What is an issue with HAART?

Answer 44

very expensive

Question 45

At what CD4 count does a person basically have normal immunity? What is an HIV CD4 count where opportunistic infections may become a problem?

Answer 45

500+ 499-200 (although not definite numbers, some people can be better with less, some worse with more)

Question 46

What is the Kaposi sarcoma AIDS defining agent?

Answer 46

Human herpes virus 8

Question 47

How is HIV transmitted?

Answer 47

heterosexual sex, needle sharing for IV drugs, hemophelia treatment, blood transfusion, homosexual sex as well

Question 48

What is the risk to caregivers after a needle prick?

Answer 48

1/300

Question 49

How acn the seroconversion rate of accidental healthcare exposure be decreased?

Answer 49

with PEP - post-exposure prophylaxis (combivir + Kaletra)

Question 50

What may ultimately be one answer to the HIV pandemic?

Answer 50

HIV vaccines