HIV

Question 1

Retrovirus

Answer 1

converts viral RNA into DNA. DNA gets integrated into host DNA to form a provirus

Question 2

Acute HIV syndrome

Answer 2

flu-like symptoms
active virus replication happens in blood and CSF
Lymphoid organs “seeded:”” with virus

Question 3

When does seroconversion take place

Answer 3

6-9 weeks after exposure to virus

Question 4

Window period

Answer 4

patient is producing antibodies, but all serologic tests are negative . This is a dangerous time because they could be passing the virus without realizing it

Question 5

Asymptomatic Infection (aka latent phase)

Answer 5

seropositive
can last a really long time (10 years)
unknown exactly what triggers a patient to go from the latent to active phase

Question 6

AIDS-related complex (ARC)

Answer 6

majority of patient’s don’t go through this phase. Those that do tend to have high viral loads
without treatment they die relatively quickly of AIDS

Question 7

What are the symptoms of ARC

Answer 7

persistent fevers, night sweats, weight loss, chronic diarrhea, inflammatory skin conditions, lymphadenopathy
some get oral candidiasis and/or chronic mucocutaneous herpes simplex infection

Question 8

Clinic findings of AIDS

Answer 8

recurrent infections
kaposi’s sarcoma or non-hodgkin’s lymphoma
progressive wasting syndrome (cachexia)
dementia

Question 9

What is responsible for cachexia

Answer 9

TNF-alpha

Question 10

Clinical definition of AIDS

Answer 10

CD4+ count drops below 200

Question 11

HIV variants that use ____ (expressed on macrophages and memory T cells) are called _____

Answer 11

CCR5

R5

Question 12

HIV variants that use ______ (expressed on T cells) are called ______

Answer 12

CXCR4

R4

Question 13

HIV that can bind to both CCR5 and CXCR4 is called what?

Answer 13

R5X4

Question 14

Plasma membrane-expressed gp120 binds to what

Answer 14

CD4 on nearby cells

Question 15

What does the binding of gp120 to CD4 initate? and what is the result?

Answer 15

membrane fusion

passes HIV genomes to uninfected cells

Question 16

What happens once HIV is inside the cell?

Answer 16

viral replication or proviral state

Question 17

transcription factors _____ and______ which bind HIV long terminal repeastz that control viral gene transcription

Answer 17

NFkB

SP1

Question 18

_____ and _____ induces HIV transcription/replication in T cells

Answer 18

TNF-alpha

IL-2

Question 19

What induces HIV replication in monocytes and macrophages

Answer 19

IL-1, IL-3, IL-6, TN-alpha, IFN-gamma, and GM-CSF

Question 20

How does HIV affect monocytes/macrophages

Answer 20

they are not as prone to lysis

instead they can serve as in vivo reservoir and transport the virus throughout the body

Question 21

What are macrophage and/or virus-mediated effects on CNS

Answer 21

AIDS dementia complex, which leads to memory loss

Question 22

Dementia

Answer 22

direct virus infection of neurons or destruction of neurons by macrophage-derived cytokines

Question 23

How does HIV affect T cells

Answer 23

lyses them

Question 24

How does HIV kill T cells

Answer 24

direct lysis by budding HIV
virus production which interferes with cellular protein synthesis
syncytia formation
binding of gp120 to infected and uninfected T cells results in antibody response, ADCC
CTL mediated destruction

Question 25

2 other ways HIV messes with the immune system

Answer 25

binding of free gp120 to CD4 of uninfected cells makes those cells unable to bind to class II MHC proteins
destroys follicular dendritic cell network

Question 26

Truncated CCR5 variants

Answer 26

seronegative even after repeat exposure to HIV

Question 27

What type of response was found in female gambian/kenyan sex workers to repeat exposure to HIV

Answer 27

no significant antibody response, but potent CTL response

after leaving the industry and coming back more were infected, possibly because absence of frequent exposure to HIV

Question 28

Who might get a false positive with ELISA testing?

Answer 28

multiparous females

patients with autoimmune disease

Question 29

What test should you use if you get two positives with ELISA?

Answer 29

Western blot

Question 30

PCR

Answer 30

very sensitive

can use to determine if neonates have been infected