final exam bieb 152

If you want to detect recombinant viruses in an vitro experiment using HIV, what kind of technique can you use?

• 1. You apply antiviral drugs such that only recombinant viruses survive

• 1. You co-culture the virus with CTL such that infected cells are killed, except those infected with recombinant virus

• 1. You co-culture the virus with antibodies such that viruses are killed, except recombinant viruses

• 1. B or C would work

• 1. You introduce fluroescent reporter genes into the virus. One cyan fluorescent protein, and one Yellow fluorescent protein. When both reporters are brought together in the same genome through recombinantation, the infected cell glows green

Can the following statements be true: “In HIV infection, the number of infected cells in the follicular and extrafollicular compartments of the lymphoid tissues is similar to each other”

• A) Yes

• B) No, there is always more virus in the follicular compared to the extra follicular compartments because the follicles represent an immune-privileged site

• C) No because CTL cannot enter follicles in significant numbers

• D) No because CTL cannot enter the extrafollicular compartment in significant numbers

• E) B and C

Answer explanation

If theres a strong CTR response, itll suprress the virus in the EF compartment, and it wont suppress it in the follicular compartment. (Big difference in virus lvl)

If you have no CTL or weak CTR response, then they'll be similar since theres nothing killing the virus in the follicles and in the EF compartments

What is meant by spatial population structure in evolutionary models?

• 1. A) Subdivision of the population into demes or patches

• B) Interaction of individuals only with their nearest neighbors rather than everyone in the population

• C) Interactions of individuals only with other individuals of their own species 

• D) A and B

• E) A, B, and C

What are consequences of formulating evolutionary dynamics in spatially structured populations?

• A) The number of mutants when measured at a threshold population size in a growing population can be larger if spatial structure is assumed compared to if well-mixed populations are assumed

• B) Different selection pressures can apply at different spatial locations, which can have profound influences on the evolutionary dynamics

• C) Selection pressures are always identical regardless of spatial location, leading to evolutionary dynamics

• D) A and B

• E) A, B, and C

Tags

NGSS.HS-LS2-6

In recent years, so called engineered CAR T cells(CTL) have been generated that can home to the follicles of the lymphoid tissue (I.e. migrate there). Assume that you inject those CAR T cells into monkeys infected with SIV that have strong CTL responses and control the virus at relatively low levels. What do you expect to happen?

• A) The number of infected cells in the follicular compartment would decline substantially

• B) The number of infected cells in the extra follicular compartments would decline substantially

• C) The number of infected cells in the follicular compartment would increase substantially

• D) The number of infected cells in the extra follicular compartments would increase substantially

• E) None of the above

Answer explanation

CTL dont normally go to the folliciles, if you inject them then itll just go in and kill the infected cells so there it'll thus kill off infected cells

Assume that a mouse does not develop CTL memory, and hence a virus infection persists instead of being cleared. How could you hypothetically change the outcome such that the infection is cleared?

• A) You knock out T cell help

• B) You knock out B cell responses

• C) While the virus population declines, you periodically and frequently inject CTL such that CTL-mediated pressure is maintained as the virus declines

• D) B and C

• E) A and C

Answer explanation

Memory can keep immunological pressure up as the virus population declines and that results in clearance, if the immunological pressure goes down then you get persistence.

Immune pressure HAS to be maintained as the virus population declines

When you treat an SIV-infected monkey with antiviral drugs, you observe the same rate of infected cell decline in CTL-depleted animals as you do in those animals where CTL were not depleted. Why?

• A) Because CTL act largely in a non-lytic way in SIV infection

• B) Because you measure the number of infected cells over time in the blood

• C) Because CTL do not enter the follicular compartments in significant numbers

• D) Because the number of infected cells is substantially higher in the follicular than in the extra-follicular compartments in the presence of relatively strong CTL

• E) B, C, and D

Consider the following experiment. You infect a monkey with SIV. You isolate virus from early chronic infection, and also from late chronic infection. You take these 2 isolates and infect each into the blood stream of different recipient monkeys. In those recipient monkeys, what do you expect?

• A) The setpoint virus load after acute infection is larger for the late compared to the early chronic phase isolate

• B) The setpoint virus load after acute infection is larger for the early compared to the late chronic phase isolate

• C) Recipient monkeys infected with the early isolate show a higher peak acute virus load, and a lower set-point virus load compared to recipient monkeys infected with the last isolate

• D) Recipient monkeys infected with the early isolate show a lower peak acute virus load, and a higher set-point virus load compared to recipient monkeys infected with the late isolate

• E) None of the above, because infection through injection into blood is never successful. Infection of the recipient monkey can only occur through the genital tract.

Answer explanation

Take something from early infection or something to late infection, something in late infection is more virulent and if you put something more virul more advanced disease progression into a recipient monkey, then this higher virulence will cause a higher set point virus load.

Tags

NGSS.HS-LS3-2

NGSS.HS-LS4-2

Why is the selection-mutation balance lower for an HIV mutant that is simultaneously resistant against 2 drugs than for a mutant that is resistant against a single drug?

• A) Because a mutant that is resistant against 2 drugs is characterized by a higher mutation rate

• B) Because the mutant resistant against 2 drugs is generated from mutants that are resistant against a single drug, the population size of which is lower than that of the drug-sensitive virus population

• C) Because the mutant resistant against 2 drugs is generated from mutants that are resistant against a single drug, the population size of which is higher than that of the drug-sensitive virus population

• D) BEcause it takes longer to make a double mutant than a single mutant during one reverse transcription event

• E) B and D

Tags

NGSS.HS-LS4-2

What would happen if an HIV mutant that is resistant against 1 drug had a selective advantage compared to the drug sensitive virus, assuming that both viruses are in competition and infect the same target cell population (CD4 T Cells)?

• A) The virus population in chronic infection would be made up entirely of viruses resistant against this drug before the start of therapy

• B) Before the start of antiviral therapy, the virus population would consist entirely of drug sensitive virus

• C) The virus strain resistant against this drug would exist at a selection-mutation balance, at a small fraction of the total virus population

• D) The drug resistant virus would be more likely generated during the phase of anti-viral therapy

• E) Virus strains that are simultaneously resistant against 2 drugs would not be present

Answer explanation

Its takeover out competing the inferior virus population.

The virus strain resistance against this drug would exist in a selection mutation balance that would happen if it was disadvantageous but its advantageous

So its the opposite it'll take over and become successful!!!! Selective advantage over competitor

Tags

NGSS.HS-LS4-2

NGSS.HS-LS4-4