HIV

Question 1

Most common types of reteroviruses

Answer 1

HIV-1/2 and HTLV

Question 2

Retrovirus genetic make up

Answer 2

Single-stranded, (+)-sense RNA with two copies.

- transcribes its own DNA via reverse transcription and implants it into host cells, causing lifelong exposure

Question 3

Steps of HIV replication cycle

Answer 3

Virus attachment and fusion

Reverse transcription within host cytosol

Integration of reverse transcribed DNA into host DNA

viral transcription

Viral translation

Assemble, budding and maturation of the new virions

Question 4

Cores structural proteins of HIV genome

Answer 4

P15/18/24

• generated via the Gag precursor (pr55)
• P24 is the most important since it is the immunological marker sued to determine that someone has HIV*

Question 5

Viral enzymes of HIV genome

Answer 5

P10 (protease)

p32 (integrase)

PP 65/66 (reverse transcriptase)

Generated via the Pol precursor (p160)

Question 6

Envelope proteins of HIV genome

Answer 6

GP120 (primary docking protein)

GP41 (transmembrane glyco protein)

• generated via the Env precursor (gp160)

Question 7

Accessory proteins of HIV and their function

Answer 7

Tat = increases viral RNA synthesis
- required to transcribe enough viral RNA to generate an infection

Rev = transport full length RNA from nucleus
- required to package the RNA and make new virons

Nef = perturbs cell signaling and enhances infectivity

Vif/Vpr/Vpu = control cellular restriction factors

Question 8

Attachment of the HIV virus

Answer 8

Mediated by gp120 and gp 41

• gp120 is hyper variable and often presents with mistakes when being transcribed due to reverse transcriptase not being able to fix mistakes.
• Makes it harder for adaptive immune system to make antibodies for it

Infects CD4+ cells only
- does this via binding to CD4 receptor and chemokines coreceptor

Coreceptors function to make gp41 bind more efficiently to the CD4 T cells
- CCR5, CXCR4

• must have both go 120:DC4 and GP41: CCR5/CXCR4 in order to enter cell*

Question 9

Native Env Trimer

Answer 9

GP41

Gp120

V1/2

Question 10

Which protein mediates entry of the HIV pathogen

Answer 10

GP41

Question 11

When does the HIV virus become infectious?

Answer 11

Once protease cleavage occurs

• until this occurs, the HIV is in the immature variant form (cant infect)
• this occurs after the budding and the release stage.

Question 12

What white cells are infected in HIV/AIDS

Answer 12

T helper cells (CD4)

Monocytes/macrophages

Question 13

Three stages of HIV

Answer 13

Acute retroviral syndrome (HIV)

• transmitted via body fluids
• 2-3 month timeframe
• Ab to HIV negative with positive viral load

Prolonged asymptomatic state
- time between HIV and AIDS where chronic infection is progressing but Immune status is not low enough yet

Acquired immunodeficiency syndrome (AIDS)
- usually takes 10 years from HIV to develop

Question 14

Ways HIV is spread

Answer 14

Unprotected sex

Anal sex

Pregnancy/breastfeeding

Sharing syringes or drug equipment

• only infectious if viral load is detectable and not controlled.*

Question 15

Primary symptoms of acute HIV

Answer 15

Mononucleosis or flu-like symptoms

• fever
• lymphadenopathy
• malaise
• pharyngitis

Question 16

When is HIV RNA and P24+ detectable in the host body and when is antibodies produced?

Answer 16

HIV RNA = at the time of infection

P24+ in blood samples = 20 days 
*This usually coincides with development of symptoms and class switching to IgG antibodies*

Antibodies = 45 days

Question 17

What is the point in which AIDS is diagnosable?

Answer 17

When CD4 cells are 200/mm3 or lower

Question 18

HIV screening

Answer 18

13-64 year olds should be screened at least once as a routine health care
- gay men need to be screened more frequently

Question 19

Diagnosis of HIV infection

Answer 19

P24 core antigen test
- (+) = has it

RNA detection viral load

CD4+ count
- low numbers could mean HIV

Test for associated STIs
- gonorrhoeae/ chlamydia (+) increases chances of acquiring HIV

Question 20

How it can be confirmed negative for HIV?

Answer 20

Wait 20 days after exposure and then run the tests

• negative for antibodies to HIV 1/2 and negative for p24 = NO HIV

Question 21

common Symptoms of AIDS

Answer 21

Chronic fever

Weight loss

Persistent diarrhea

Lymphadenopathy w/ oral lesions

Fatigue

Pneumonia and other opportunistic infections
- only present when CD4 counts are lower than 200 cells/mm3 and not taking prophylactic drugs

Question 22

Common opportunistic infections for AIDS patients

Answer 22

Pneumocystis jirovecii

Cryptosporidium

Cryptococcus

Candida

Cytomegalovirus

HHV-8

Usually start within 9-10 years of having HIV (right before or at the clinical stage of AIDS)

Question 23

Common cancers that are more common in AIDS patients

Answer 23

Kaposi sarcoma

Non-Hodgkin lymphoma

Lymphocytic leukemia

Hodgkin lymphoma

Burkitt lymphoma

Liver cancer

Mouth/throat cancer

Question 24

Categories of HIV therapeutics

Answer 24

Integrate inhibitors

Reverse transcriptase inhibitors
- block conversion of HIV RNA -> HIV DNA

Fusion/entry inhibitors

Protease inhibitors

Question 25

Two types of reverse transcription inhibitors

Answer 25

Nucleoside - binds directly to DNA chain being reverse transcribed and prevents it from finishing Non-nucleoside - denatures the reverse transcriptase enzyme

Question 26

Most common antiretroviral therapy’s

Answer 26

Based on baseline resistance and co-infections Requires life-long adherence Usually requires at least 3 of the inhibitors

Question 27

Types of HIV targets for treatment

Answer 27

Integrase inhibitors Reverse transcriptase inhibitors - both NNRTIs and NRTIs Fusion/entry inhibitors Protease inhibitors

Question 28

PrEPs and PEP agents/regiments

Answer 28

Are both prophylaxis regiments for HIV used for people who have high chances of exposure PrEPs (truvada) is for pre-exposure PEP is for post-exposure