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Why has it been so difficult for researchers to developeffective antivirals for HIV?

because the virus is able to produce DNA as an intermediate inviral replication

because HIV has a high mutation rate

due to the damaged helper T cells that are targets for HIV

because evolution favors a rapidly expanding viralpopulation

because HIV is a sexually transmitted viral disease

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Jamar Ferry
Jamar FerryLv2
28 Sep 2019

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Related questions

Below is a paragraph describing HIV infection as they relate to the progress of infection. Please help choose the correct answer in each parentheses.

HIV initially infects (CD4+, or CD8+, or B) cells. These are helper T cells that activate (CD4+ or ,CD8+ or, B) cytotoxic T cells and (CD4+, or CD8+, or B) cells which produce antibodies. If HIV kills (CD4+, or CD8+) T cells then they cannot to do their job of activating these cells thus causing HIV infected people to be immunocompromised. Sometimes HIV infected people enter a latency period where the virus is inactive. This latency period can last for several years. During latency HIV (DNA, or RNA) becomes integrated into the (CD4+ or CD8+, or B) host cells genome and stops producing viral HIV RNA and new HIV virions. However, for some unknown reason, HIV comes out of dormancy and the viral (RNA, or DNA ) that was integrated in the (CD4+ , or CD8+,) T cell genome begins to transcribe more viral (DNA , or RNA) to make more viral (DNA, or RNA) using the host cells machinery. The viral (DNA, or RNA) then gets translated by host cell ribosomes to make viral proteins that eventually become packaged into new HIV virions. Consequently, after the latency period HIV becomes activated in the host cell. These cells present HIV antigen on their cell surface and alert (CD8+ or CD4+ or B) cells to kill them. As they are killed the infected (CD4+, or CD8+, or B) cells release the HIV virions into the blood stream to infect other (CD4+ or CD8+) cells such as macrophages and dendritic cells. This explains why after latency we see (CD4+, or CD8+) T cells continue to decrease while at the same time viral (DNA, or RNA) levels increase.

Based on your answers to the fill in paragraph, which statement is true?

A. Once active in CD8+ T cells, HIV can now replicate with impunity and infect other cells which explains the increase in HIV RNA after latency.

B. The increase in active HIV after latency accounts for why HIV can remain dormant for years after the initial infection.

C. CD4+ levels stabilize after the latency period and explain why there is little increase in HIV RNA levels.

D. Opportunist infections can occur after HIV latency because there are very few helper T cells to left to activate cytotoxic T cells and B cells to mount an immune response.

1. A mutation in the gene encoding the integrase enzyme rendersthe protein non-functional. How would the affect the HIV infectioncycle?

Formation of the provirus would be stopped.
Reverse transcription would no longer be possible.
The gp120 glycoprotein would no longer be able to bind to the CCR5receptor.
Cutting and assembling the capsid would be halted.

2. If the viral gene is AUGCCCAGG and the mRNA used to make theviral protein is UACGGGUCC, then the virus is a :

Negative strand RNA virus
Double stranded DNA virus
Retrovirus
Positive strand RNA virus

3. Would treating prions with enzymes that digest nucleotides bean effective neutralization method?

No, prions lack amino acids.
Yes, prion nucleic acids would be susceptible to enzymaticdigestion.
No, prions lack phosphodiester bonds and would not be subject todigestion by these types of enzymes.
Yes, the bonds between the amino acids would be hydrolyzed.

4. Most Americans born before 1970 have a permanent scar ontheir shoulders from the smallpox vaccine. Why don't youngerAmericans have one?

Smallpox has been eradicated by a worldwide vaccinationprogram.
Smallpox is no longer lethal.
A safer less damaging vaccine was developed in the early1970's.
The vaccine is no longer effective due to antigenic shift.

5. What kind of pathogen would retain its ability to causeinfections after being treated with powerful proteolytic chemicalsthat would destroy all proteinaceous material?

A virus
A bacterium
A prion
A fungus
A viroid

6. Select all of the false statements concerning AIDS.

AIDS kills the patient.
Patients die as a result of opportunisticinfections.
AIDS shuts down the immune system.
HIV therapy (HAART) can clear the virus from thebloodstream.

HIV therapy (HAART) can clear the virus from the patient'sbody.

7. Why do viruses only infect specific types of cells?

Viruses only attack epithelial cells, such as the cells liningthe lungs.
If a host cell is weakened, viruses have an easier time infectingit.
The initial choice is random but once a cell type is chosen itbecomes the preferred host.
The host cells have the correct surface receptor that the virus canfit into.
Viruses infect the first cells they encounter.

8. Nucleotide analogs are a class of drugs that are highlyeffective against many types of viruses. They work by halting thereplication of viral genes. They are equally effective at stoppingthe spread of prion diseases.

True
False

9. An experimental chemical has been shown to selectively cleavephosphodiester bonds. How would the affect a virus?

Dissociate the envelope
Fragment the genome
Hydrolyze the protein coating
Alter the host binding site
Digest the capsid

10. HIV uses cell surface receptors to enter host cells. Whydoes switching from a CCR5 co-receptor to a CXCR4 co-receptoreventually shut down the immune system?

Macrophages have CCR5 co-receptors.
T-helper cells have CXCR4 co-receptors.
T-helper cells are not involved in coordinating immuneresponses.
Only macrophages are killed by HIV.

1. A mutation in the gene encoding the integrase enzyme rendersthe protein non-functional. How would the affect the HIV infectioncycle?

Formation of the provirus would bestopped.
Reverse transcription would nolonger be possible.
The gp120 glycoprotein would nolonger be able to bind to the CCR5 receptor.

Cutting and assembling the capsid would be halted.

2. If the viral gene is AUGCCCAGG and the mRNA used to make theviral protein is UACGGGUCC, then the virus is a :

Negative strand RNA virus
Double stranded DNA virus
Retrovirus

Positive strand RNA virus

3. Would treating prions with enzymes that digest nucleotides bean effective neutralization method?

No, prions lack amino acids.
Yes, prion nucleic acids would besusceptible to enzymatic digestion.
No, prions lack phosphodiesterbonds and would not be subject to digestion by these types ofenzymes.

Yes, the bonds between the amino acids would be hydrolyzed.

4. Most Americans born before 1970 have a permanent scar ontheir shoulders from the smallpox vaccine. Why don't youngerAmericans have one?

Smallpox has been eradicated by aworldwide vaccination program.
Smallpox is no longer lethal.
A safer less damaging vaccine wasdeveloped in the early 1970's.

The vaccine is no longer effective due to antigenic shift.

5. What kind of pathogen would retain its ability to causeinfections after being treated with powerful proteolytic chemicalsthat would destroy all proteinaceous material?

A virus
A bacterium
A prion
A fungus

A viroid

6. Select all of the false statements concerning AIDS.

AIDS kills the patient.
Patients die as a result ofopportunistic infections.
AIDS shuts down the immunesystem.
HIV therapy (HAART) can clear thevirus from the bloodstream.

HIV therapy (HAART) can clear the virus from the patient'sbody.

7. Why do viruses only infect specific types of cells?

Viruses only attack epithelialcells, such as the cells lining the lungs.
If a host cell is weakened, viruseshave an easier time infecting it.
The initial choice is random butonce a cell type is chosen it becomes the preferred host.
The host cells have the correctsurface receptor that the virus can fit into.

Viruses infect the first cells they encounter.

8. Nucleotide analogs are a class of drugs that are highlyeffective against many types of viruses. They work by halting thereplication of viral genes. They are equally effective at stoppingthe spread of prion diseases.

True

False

9. An experimental chemical has been shown to selectively cleavephosphodiester bonds. How would the affect a virus?

Dissociate the envelope
Fragment the genome
Hydrolyze the protein coating
Alter the host binding site

Digest the capsid

10. HIV uses cell surface receptors to enter host cells. Whydoes switching from a CCR5 co-receptor to a CXCR4 co-receptoreventually shut down the immune system?

Macrophages have CCR5co-receptors.
T-helper cells have CXCR4co-receptors.
T-helper cells are not involved incoordinating immune responses.
Only macrophages are killed byHIV.

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