Retroviruses 2

Question 1

CXXR4 role

Answer 1

co receptor for T tropic HIV. binds SDF-1 which can block T tropic infection

Question 2

Vir role

Answer 2

restriction factor, causes cellular antiviral protein to be degraded so that it cannot be incorporated into new virions where it would block RT in the next cell by inducing massive mutations in viral DNA

Question 2

level of CD4 depletion AIDS phase

Question 3

Serology cant detect HIV infection until

Answer 3

4-6 weeks post infection

Question 3

Classes of HIV drugs

Answer 3

RT inhibitor, Protease inhibitor, Fusion inhibitor, Entry inhibitor, integrase inhibitor

Question 4

___ clears viremia during asymptomatic phase, CD4 declines

Answer 4

FDC

Question 5

6 additional accessory proteins required for HIV pathogenesis

Answer 5

Vif, Vpr, Vpu, Nef, Tat, Rev

Question 5

mechanism of direct killing via HIV

Answer 5

massive virus production > membrane leakage AND syncitia of infected cells fuse via Env (infected) CD4/CCR5 (healthy) interactions AND apoptosis induced by infection

Question 6

indirect effects of killing via HIV

Answer 6

CD4 cells >> immune response kills infected cells, soluble gp120 binds uninfected cells, which are then susceptible to ADCC

Question 7

CCR5 role

Answer 7

co receptor for M tropic HIV, receptor for RANTES, MIP-1a, MIP 1B

Question 7

methods of testing

Answer 7

Serology, RNA RT-PCR (virus in blood) Real-time RT-PCR (quantifies virus in blood)

Question 8

RANTES, MIP-1a, MIP-1B role

Answer 8

chemokines specifically inhibit M tropic HIV by occupying CCR5

Question 10

infect primary Tcells and T cell lines, but not macrophages, associated with progression and arise at AIDS stage

Answer 10

T-tropic HIV

Question 12

Dendritic cell role in HIV infection

Answer 12

can be infected, disseminate, but not productively infected

Question 13

homozygous 32bp deletion in ___ gene makes individual incredibly resistant to HIV infection

Answer 13

CCR5

Question 14

macrophage role in HIV infection

Answer 14

infected but not efficiently killed, HIV resevoir

Question 14

after exposure co-receptor binding site via conformational change in env, ___ domains are exposed and enter cell membrane

Answer 14

gp41 fusion domains

Question 15

during asymptomatic phase ___ traps virus, keeping viremia low, but nodes (especially ____) are major sites of replication

Answer 15

FDC traps virus, but GALT major region of replication

Question 17

Tat role

Answer 17

transactivator of transcription (required for transcription)

Question 19

Stromal derived factor 1 role (SDR-1)

Answer 19

cytokine, natural ligand for CXRC4, coreceptor for T tropic

Question 20

Co-receptor engagement triggers ____ of the N and C terminal helical regions of gp41 and fuses them together

Answer 20

snapback

Question 21

initial receptor for HIV

Answer 21

CD4

Question 23

Rev role

Answer 23

regulator of virion expression - allows strucutral gene expression by promoting transport of unspliced RNA to cytoplasm

Question 24

infect primary Tcells and macrophages but NOT Tcell lines, responsible for inititial infection and transmission, predominant in asymptomatic

Answer 24

M tropic

Question 25

Vpu role

Answer 25

promotes virion releasse from cells by inhibiting host tetherin, works on other enveloped viruses

Question 26

in initiation of binding, ___ contacts CD4 and induces a conformtion change in ___ to expose the coreceptor binding site

Answer 26

Env

Question 27

duration of HIV in body

Answer 27

75 years (memory Tcells)

Question 28

Microglia role in HIV

Answer 28

infected > contribute to AIDS dementia