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IHO Week 6 (EH) > HIV-1 > Flashcards

HIV-1 Flashcards

1
Q

HIV-1 genome

A

Two copies of positive polarity RNA

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2
Q

HIV-1 capsid symmetry

A

icosahedral

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3
Q

HIV envelope?

A

Yes, includes gp120 and gp41

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4
Q

gp120

A

interact with CD4 to attach to T cells

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5
Q

CD4 =

A

TCR coreceptor for recognizing antigen

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6
Q

CXCR4 and CCR5

A

cell homing, interact with growth factors

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7
Q

gp41

A

injection of viral contents into host cell

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8
Q

New HIV cases annually

A 
US = 44,000
Worldwide = 2 million
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9
Q

People living with HIV-1 infection

A 
US = 1.2 million
Worldwide = 36.9 million
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10
Q

Minnesota HIV

A

7 dx per 100,000

vs. Louisiana = 36.6
vs. Montana = 1.9

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11
Q

gag

A

capsid proteins (p24 et al)

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12
Q

pol

A

reverse transcriptase, protease, integrase

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13
Q

env

A

envelope glycoproteins gp120 and gp41

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14
Q

LTRs

A

3’ and 5’

integration sites, bind host transcription factors NF-kB, Sp1, TBP

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15
Q

The HIV-1 genome is ____ and _____, with genes encoded on _________.

A

The HIV-1 genome is small and compact, with genes encoded on multiple overlapping reading frames.

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16
Q

The products of the gag, pol and env genes make up ________

A

the functional HIV-1 infectious particle

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17
Q

Gene products, eg. tat, rev and nef, encode ______

A

transcriptional regulators

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18
Q

The binding of the infectious HIV-1 particle to the host cell is initiated by ___________

A

interaction between gp120 and CD4.

19
Q

_________ is also required to initiate infection.

A

Interaction between a host chemokine receptor (CXCR4 or CCR5) and gp41

20
Q

_________ can occupy HIV-1 binding sites on ______ and block infection.

A

Stromal derived factor (SDF-1) on CXCR4

21
Q

________ may be associated with natural resistance to HIV-1 infection.

A

SDF-1 polymorphisms

22
Q

SDF-1 normal function

A

to bind CXCR4 on lymphocytes and direct their homing to tissues.

23
Q

HIV steps in infection cycle

A

gp120 bind CD4, gp41 bind chemokine receptor –> fusion and insertion into cell
RNA via RT –> dsDNA
integrase inserts into cellular DNA = provirus
Expression of viral genes to make viral proteins and viral genomes
Proteolytic processing of viral proteins
Assembly of viral particles and budding from host cell

24
Q

normal binding of CXCR4

A

Stromal derived factor -1 (SDF-1) normally functions to bind CXCR4 on lymphocytes and direct their homing to tissues.

25
Q

HIV pathology, binding of CXCR4

A

HIV-1 infected T cells (provirus) express env proteins on their cell surface. Binding of env to CXCR4 induces autophagy. This is a major cause of CD4+ T cell loss in HIV-1 infection.

26
Q

Major cause of CD4+ T cell loss in HIV-1 infection

A

HIV-1 infected T cells (provirus) express env proteins on their cell surface. Binding of env to CXCR4 induces autophagy.
Bystander

27
Q

IL-2 response

A

Th1, activates CTLs (CD8+ T cells)

28
Q

IL-4, 5, 6 response

A

Th2, activates B cells to become plasma cells

29
Q

Th1 cells

A 
IL-2, IFN-g, IL-3, TNF-a, TNF-b, GM-CSF
induce CD8+ CTLs
B cell IgG antibody
Macrophage activation (M1)
Inhibit Th2
30
Q

Th2 cells

A 
IL-3, IL-4, IL-5, IL-6, IL-10, IL-13
Inhibition of Th1
Eosinophils
Mast cells, basophils
B cell IgM, G, A, and E antibodies
31
Q

CD4+ T cells mediate immune responses against

A

viruses, bacteria, fungi, parasites and cancer.

32
Q

Opportunistic Infections

A

Viral:
Kaposi sarcoma virus (KSV, HHV-8)
Cytomegalovirus (CMV, HHV-4)

Fungal:
Candida

Protozoa:
Cryptococcus
Pneumocystis (?)

33
Q

p24 is a

A

capsid protein encoded by gag

spikes right away, detectable before p24 antibodies, then goes down as antibody increases, and then grows again

34
Q

To diagnose HIV

A

ELISA, confirmed by western blot

35
Q

To monitor patients with HIV

A

CD4+ T cell enumeration by flow cytometry

Polymerase chain reaction: viral RNA or DNA

36
Q

Goal of therapy for patients with HIV

A

reduce level of circulating virus

37
Q

A 53 year old female is HIV-1 positive with a CD4 count of 130 cells/uL. She has Kaposi sarcoma lesions on her arms and torso which first appeared one month ago.What is the most likely cause of her Kaposi sarcoma?

A

Inefficient activation of CD8+ T cells

38
Q

A patient’s blood was collected and labeled with fluorescent antibodies against CD3, CD4 and CD8. In the dot plot, only CD3 positive cells are shown. What cells are represented by the dots in the upper right quadrant?

A

Immature T cells

39
Q

What is the structure of a nucleoside

A 
No phosphate (phosphate = nucleotide)
Base, ribose sugar
40
Q 
A 19 year old male had unprotected sex with a person who was HIV positive.  The next day, he asked his family physician whether he had contracted HIV.  What screening test would detect HIV the soonest after exposure?
CD4+ T cell enumeration
Indirect ELISA for anti-p24 antibodies
PCR for viral mRNA
RT-PCR for viral DNA
Sandwich ELISA for p24 antigen
Western blot
A 
Sandwich ELISA (direct) for p24 antigen 
p24 antigen spikes soon after infection as the virus disseminates systemically
41
Q

A 25 year old HIV-1 positive male is on a combination antiretroviral drug regimen, but his compliance has been sporadic. His CD4 count has recently declined to 250 cells/ul. His physician is developing a new treatment plan.In this patient, if 1 in 105 viral particles are resistant to ziduvudine and 1 in 106 viral particles are resistant to lopinavir, what is the probability that a viral particle will be resistant to both zidovudine and lopinavir?

A

1 in 10^11

42
Q

A 38 year old male immigrant from Cap-Haitien, Haiti presents with a dry cough that has persisted for three weeks. He is confirmed to be HIV-1 positive, with levels of CD4 cells and viral RNA consistent with AIDS. Microscopic analysis of induced sputum show P. jirovecii sporozoites.The first line treatment for his pneumonia targets. . .

A

Trimethoprim - Sulfamethoxazole

sequential steps in tetrahydrofolic acid synthesis.

43
Q

An 18 year old female is infected with HIV-1 and is being treated with multiple drugs including ritonavir. What is ritonavir’s mechanism of antiviral action?

A

Protease inhibitor

44
Q 
A 42 year old HIV-1 positive female is showing disease progression despite a HIV-1 treatment regimen consisting of zidovudine, abacavir and atazavavir with ritonavir boosting.  Testing indicates the presence of abacavir resistant virus.Which drug should be included in a new drug regimen?
abacavir
didanosine
emtricitabine
lamivudine
nevirapine
A 
Zidovudine = AZT (NRTI)
Abacavir = NRTI

Atazanavir/Ritnoavir = Protease inhibitors

Abacavir resistance --> also get zidovudine resistance and other NRTI resistance so no: 
abacavir
didanosine
emtricitabine
lamivudine

Use nevirapine = NNRTI (no cross resistancE)

IHO Week 6 (EH) (9 decks)

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