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Microbio Ex 1 > Ex 2- Retroviruses, AIDS, & Tumor Viruses- Middleton > Flashcards

Ex 2- Retroviruses, AIDS, & Tumor Viruses- Middleton Flashcards

1
Q

____ ___ discovered rous sarcoma virus

A

peton rous

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2
Q

David Baltimore and Howard Temin discovered ______ _____

A

reverse transcriptase

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3
Q

Bob Gallo isolated ____ the first retrovirus associated with human disease

A

HTLV-1

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4
Q

What are the 4H risk group for HIV/AIDS?

A
  • Homosexual men
  • Heroine Addicts
  • Haitians
  • Hemophiliacs
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5
Q

What are the two types of HIV?

A

HIV-1

HIV-2

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6
Q

HIV-2 is mostly a __________ disease

A

heterosexual

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7
Q

What is the evolution of the HIV virus?

A

Simian virus (SIV) –> HIV-2 –> HIV-1

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8
Q

______ are a large and diverse group of viruses with a unique replication cycle

A

retroviruses

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9
Q

What makes the retrovirus replication cycle unique?

A

use of reverse transcriptase

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10
Q

Retrovirus is _______ in vertebrates, many benign causing little to no impact on host cell or animal while others have significant pathogenicity causing disease and cancer

A

ubiquitous

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11
Q

_______ do not cause human disease but make “foamy” structures inside cells they do infect

A

spumaviruses

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12
Q

What are the two subfamilies of retroviridae

A
  • orthoretroviridae

- spumaviridiae

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13
Q

What is the genome of retrovirus? Where does it replicate?

A

(+) ssRNA, diploid identical copies

- nucleus exception

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14
Q

The virion of retrovirus is ______

A

enveloped

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15
Q

What are the proteins that retrovirus has?

A
  • reverse transcriptase
  • integrase
  • protease
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16
Q

This protein in retrovirus is involved in RNA–>DNA and DNA –>DNA

A

reverse transcriptase

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17
Q

This protein in retrovirus helps to insert part of RNA into genome (DNA)

A

integrase

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18
Q

Historically retroviruses were classified by _____ structure and _____ in the particle

A
  • nucleocapsid

- location

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19
Q

______ _____ are now used to classify retroviruses as simple or complex

A

genome contents

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20
Q

What genes does a simple retrovirus encode?

A

Gag
Pro
Pol
Env

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21
Q

What genes does a complex retrovirus encode?

A

more than the simple retrovirus does

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22
Q

What is the replication cycle of retroviruses?

A
  • attachment
  • entry
  • reverse transcription
  • integration
  • transcription from provirus
  • translation
  • assembly
  • release
  • maturation- protease activity
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23
Q

_____ ______ converts ssRNA genome to dsDNA

A

reverse transcriptase

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24
Q

________ involves virus dsDNA being inserted into host genome making a ______

A

integrase (integration

provirus

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25
Vaccines target what steps in the replication cycle of retroviruses?
- reverse transcription | - protease
26
What is the defining feature of retroviruses?
reverse transcription
27
When does reverse transcription initiate?
- once nucleocapid in cytoplasm | - needs higher levels of NTPs (nucleoside triphosphate) present
28
Low NTP levels prevent _______ ______
reverse transcription
29
Reverse transcription occurs within a _____ _____ similar to nucleocapsid
large complex
30
Retrovirus infection cannot progress if ______ ______ does not occur
reverse transcription
31
Reverse transcription is promiscuous btw ______ ______
genome copies
32
Reverse transcription is _____ when copies are identical but many different recombinations can occur when different genomes are in the virion
silent
33
For _______ to occur the virus must have access to the nucleus during mitosis bc requires dividing cells although it can infect non-dividing cells
integration
34
How is the viral genome integrated into the host genome?
- 3' end processing of dsDNA - attach target DNA, nick created - host repair
35
Integration of retrovirus DNA is _______, there is ___ mechanism to remove it
- permanent | - no
36
If integrated into the germ line (sperm or eggs) then _____ is inherited and called _______ goes to progeny
- provirus | - endogenous
37
Which types of integration is identified as oncogenes?
- TF - secreted growth factors - growth factor receptors - cell signal transduction pathways
38
Many _____ retroviruses are made during replication and are missing at least one of the ____, ___, or ___
- defective | - gag, pol, env
39
Retroviruses require _____ infection to make progeny
complementary
40
Retroviruses are ______ when they carry oncogenes
tumorigenic
41
Many retrovirus infections are _____, not cytopathic with little impact to cell replication & physiology
benign
42
_____ infections exert small demand on cell and host resources (few % of cell RNA & protein), cause viremia and elicit an immune response
chronic
43
Viruses are never eliminated by the _____ response
host
44
What are the 3 types of retroviruses?
- slow - cytopahtic - acute transformin
45
_____ retroviruses cause effects like high-level mutagenesis and eventually results in tumorigenesis
slow
46
______ retroviruses, the majority of retroviruses carry cytopathic genes and directly cause tissue damage
cytopathic
47
_______ ______ retroviruses induce rapid tumor formation, carry host genes- mitogenic or antiapoptotic and replication defective bc host gene replaces an essential gene
acute transforming
48
What are the 4 distinct types of Human T-Cell Leukemia Virus (HTLV)?
1,2,3 and 4
49
What type of Human T-Cell Leukemia Virus is most associated with humans?
HLTV-1
50
HTLV is a ______virus
deltaretrovirus
51
HTLV-1 affects ______ worldwide
millions
52
How is HTLV-1 transmitted?
Person to person | Within the host
53
How is HTLV-1 be transmitted from person to person?
- breastfeeding - sharing needles - blood transfusion - sexual (less efficient)
54
How is HTLV-1 transmitted within the host?
- highly cell associated | - contact btw infected and naive cells (WBC's)
55
What diseases are associated with HTLV-1?
- Adult T-Cell lymphoma/Leukemia (ATLL) (2-4% cases) | - HTLV-1 Associated Myelopathy/ Tropical Spastic Paraparesis (HAM/TSP (1-2% cases)
56
What is the latent period of ATLL? How is it transmitted?
30-50 yrs | mucosal infection
57
What does ATLL infect?
- memory T cells - antigen activation triggers transcription of provirus - virus tax protein stimulates cell proliferation - cells become transformed generating tumors (w/ or w/out protein exp)
58
HTLV-1 Associated Myelopathy / Tropical Spastic Paraparesis (HAM/TSP) occurs in 1-2% of cases and is transmitted by?
-tranfusions
59
HAM/TSP infects T cells that enter the central nervous system activating what cells?
- astrocytes - microglial cells - recruit inflammatory cells causes further tissue damage
60
It takes __ years after infection for HAM/TSP symptoms to appear
3
61
What are the symptoms of HAM/TSP?
- bladder control issues - lower back pain, leg weakness or stiffness in hips or knees - men suffer impotence or erectile dysfunction
62
What is used to prevent HTLV-1?
- eliminate breast feeding from positive mothers | - inc screening for blood products
63
What is used to treat ATLL?
treat lymphoma/leukemia w/ chemotherapy regardless of HTLV infection
64
What is used to treat HAM/TSP?
corticosteriods, interferon yield temp relief of symptoms
65
What are the 2 main types of HIV (lentivirus) in humans?
Type 1 & 2
66
How was HIV identified?
immune deficiency occurring in previously healthy young gay men
67
HIV prevalence is highest in ________ _____
sub-saharan africa
68
Life expectancy for people with HIV have ______ over the years
inc.
69
How is HIV transmitted?
- sexual - parenteral; transfusion, needle shring - mother to infant (AZT)
70
What are the ratios of HIV sexual transmission?
-female to male -male to female - male to male (increasing odds)
71
What is the latent period for AIDS?
6 months - 25yrs
72
HIV infection begins as virus containing blood or body fluid to ______ ____
mucosal surface
73
HIV targets memory __- cells
T-cells | CD4+
74
The initial acute infection usually __ weeks after infection
2
75
________ ulceration, ______ ______ , and Gut associated lymphoid tiissue (GLT) more indicative of HIV infection (reservoir)
- mucocutaneous | - weight loss
76
A chronic infection of HIV is established when their is ongoing ______ replication and ___ cell depletion
viral | T-cell
77
What is the result of chronic HIV infection?
- opportunistic infections increase | - wasting due to HIV infection
78
What are the prevention strategies for HIV?
- sexual behavior and protection | - blood screening
79
What are the treatments for HIV?
- no vaccine - antivirals; - -AZT is a reverse transcriptase inhibitor - -protease inhibitors - non nucleoside RT inhibitor

Microbio Ex 1 (18 decks)

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