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Micro Exam VI > HIVInfections > Flashcards

Flashcards in HIVInfections Deck (50)
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1
Q

When was AIDS recognized as clinically distinct illness?

A

1981 (due to increased cases of Kaposis sarcoma and PCC)

2
Q

Peak of death due to HIV disease in US:

A

1996

3
Q

Features of HIV Virion:

A

Envelope > Matrix > Nucleocapsid > Genome

4
Q

Attachment protein for HIV:

A

gp120

5
Q

**Fusion protein for HIV:

A

gp41

6
Q

Reverse Transcriptase for HIV:

A

HIV carries pol gene > encodes for reverse transcriptase

7
Q

**Matrix protein for HIV:

A

p17

8
Q

**Capsid protein for HIV:

A

p24

9
Q

Life Cycle of HIV: Attachment:

A

gp120 binds to CD4 > conformational change in gp120 to allow binding to a CORECEPTOR (ABSOLUTELY NECESSARY)

10
Q

Coreceptors for HIV:

A

CCR5, CXCR4

11
Q

R5-Tropic HIV:

A

Uses CCR5 as co-receptor, Predominant EARLY in disease

12
Q

X4-Tropic HIV:

A

Uses CXCR4 as a coreceptor, 40% of patients transition from R5 to X4 > rapid progression to AIDS

13
Q

Deletion to CCR5 Gene:

A

affects its binding to gp120

14
Q

Heterozygous Deletion of CCR5 gene:

A

longer asymptomatic period before onset of AIDS

15
Q

Homozygous deletion of CCR5 gene:

A

NO infection with R5-tropic viruses. X4-TROPIC CAN INFECT.

16
Q

HIV Life Cycle: Fusion:

A

gp41 mediates fusion between the viral envelope and plasma membrane

17
Q

HIV Life Cycle: Reverse Transcription:

A

pol gene found within virus > reverse transcriptase, produces a linear dsDNA copy of HIV genome

18
Q

What allows for rapid evolution of HIV during course of disease?

A

The high error rate of its reverse transcriptase. It it the MOST error prone of all retroviruses.

19
Q

HIV Life Cycle: Integration:

A

dsDNA into nucleus > VIRAL INTEGRASE causes dsDNA to be incorporated into host DNA > PROVIRUS > Provirus is transcribed

20
Q

HIV Life Cycle: Egress:

A

Progeny HIV Virions EXIT the infected cell by BUDDING through the plasma membrane at LIPID RAFTS

21
Q

HIV Life Cycle: Maturation:

A

Protease cleavage of gag and gag-pol polyproteins > ESSENTIAL FOR INFECTIVITY

22
Q

Immature vs Mature Virions

A

Light and homogenous = immature. Darker with dark nucleocapsid center= mature.

23
Q

Overall transmission risk of HIV from mother to child:

A

25%

24
Q

Highest risk of transmission of HIV from mother to child occurs when:

A

at birth (50-65%)

25
Q

Risk of HIV transmission due to skin puncture from a needle:

A

0.30%

26
Q

Risk of transmission due to mucous membrane exposure:

A

0.09%

27
Q

HIV Progression: Acute HIV Syndrome

A

3-6 weeks following infection. Burst of Viremia (p24/RNA) Anti-HIV antibodies may not be detectable

28
Q

HIV Progression: Acute HIV Syndrome Symptoms:

A

Similar to infectious mono with a rash.

29
Q

Following the initial burst of viremia with acute HIV syndrome, what happens to virus levels in the blood:

A

They decrease due to mounted immune response (anti-HIV antibodies appear)

30
Q

HIV Progression: Chronic Phase:

A

Low level viremia? Patients often asymptomatic. Untreated patients = can persist for 10 years.

31
Q

HIV escape from immune system during chronic phase of infection:

A

Antigenic drift of gp120, Inactivation of key elements of immune response, Cell-to-cell fusion (passed without going into EC area)

32
Q

*HIV-Associated Infections (6):

A

Oral Hairy Leukoplakia (EBV), Pneumonia (PCC, TB), Candida Albicans (Thrush), CMV retinitis, Neoplasms (KS), Diarrhea

33
Q

HIV Virus Family:

A

Retroviridiae

34
Q

HIV Features:

A

Envelope +ssRNA

35
Q

Serology during Acute HIV Infection:

A

High levels of HIV RNA and p24 (p24 will drop off but RNA persists as infection progresses)

36
Q

Progression of things detectable with HIV infection:

A

HIV RNA detectable by NAAT > p24 > Abs

37
Q

First screening test for HIV:

A

Testing for ANTIGEN (p24) AND ANTIBODY to HIV-1/2

38
Q

Following a HIV screening test, what is the next diagnostic step?

A

HIV-1/HIV-2 ANTIBODY differentiation Immunoassay

39
Q

Final step of HIV Diagnosis if immunoassay shows HIV- 1 (-) and HIV-2 (-):

A

HIV-1 nucleic acid test to detect HIV RNA genome

40
Q

Two classes of Entry Inhibitors and indication for use:

A

Chemokine coreceptor antagonists, Fusion inhibitors, NOT indicated for treatment of NEWLY diagnosed patients.

41
Q

*MOA + Limitation of Chemokine Receptor Antagonists:

A

Binds to co-receptor and prevent its interaction with gp120 *(limited to R5-tropic)

42
Q

MOA of Fusion Inhibitors:

A

Bind to gp41 and prevent conformational change needed for fusion

43
Q

Two varieties of Reverse Transcriptase Inhibitors:

A

Nucleoside inhibitors (NRTIs), Nonnucleoside Inhibitors (NNRTIs)

44
Q

*Method of action of NRTIs:

A

Incorporated into growing dsDNA chain and this leads to failure of chain to be integrated into host DNA.

45
Q

*MOA of NNRTIs:

A

bind to reverse transcriptase and inhibit its activity.

46
Q

Integrase Inhibitor MOA:

A

blocks integration of the DNA viral copy into the host DNA

47
Q

Protease inhibitor MOA:

A

Inhibit protease cleavage > production of IMMATURE, DEFECTIVE HIV particles

48
Q

Preferred Combination ARV Therapies for initial therapy:

A

1 NNRTI + 2 NRTIs, 1 PI + 2 NRTIs, 1 II + 2 NRTIs (2 NRTIs for EACH)

49
Q

3 ways to reduce mother to infant spread:

A

Antiviral treatment of mother and child. Refrain from breast feeding. C-section delivery

50
Q

Characteristics of HIV virus

A

retroviridae family, +ssRNA, envelope, 2 types (type 2 found mainly in western africa, has long asymptomatic period)