MSI HIV and AIDS

Question 1

In initial infection, HIV-specific ____ T cells rise sharply and reduce viral load (however, the virus is not fully cleared from the organism)

Answer 1

CD8+

Question 2

CD4+ T helper lymphocyte effect on dendritic cells

Answer 2

increase class II co-stimulation

Question 3

CD4+ T helper lymphocyte effect on B cells:

Answer 3

increase maturation and Ab class switching

Question 4

CD4+ T helper lymphocyte effect on (infected) target cells

Answer 4

Induce apoptosis

Question 5

CD4+ T helper lymphocyte effect on CD8 T cells:

Answer 5

increase cytotoxic lymphocytes and memory development

Question 6

CD4+ T helper lymphocyte effect on macrophages:

Answer 6

increase phagocytosis

Question 7

When the loss of CD4+ T helper cells weakens to the immune response to the point at which opportunistic infections occur, this is known as

Answer 7

AIDS

Question 8

What is often the first presenting illness of AIDS (as well as the cause of death)?

Answer 8

Opportunistic infections such as TB, P.jiroveci pneumonia, Karposi’s sarcoma of the skin, or toxoplasmosis (CNS infection)

Question 9

HIV binds to the CD4 and CCR5 receptors via which of the following proteins?

a) P4
b) P17
c) P24
d) gp120
e) gp160

Answer 9

d) gp120

Once gp120 binds to the CD4 and CCR5 receptor, a conformational change results in the expression of gp41 which allows the virus to enter the cell. ( It also uses a chemokine co-receptor to attach to the host cell membrane. There is a complex protein interaction and bc of this they are able to create a channel through which they can gain entry into the cell.)

Question 10

What type of cells are the primary target for HIV infection?

Answer 10

CD4 T cells

Question 11

Molecules used for HIV entry into CD4 cells?

Answer 11

Gp120 (also co-receptors CCr5 and CXCR4)

Question 12

Receptor for Rantes, MIP-1alpha? (Molecules involved in lymphocyte chemotaxis and HIV suppression)

Answer 12

CCR5

Question 13

Receptor for SDF-1? (Molecules involved in lymphocyte chemotaxis and HIV suppression)

Answer 13

CXCR-4

Question 14

Lamina propria and intraepithelial CD4 T cells in the gut (ileum, colon, rectum) express high levels of the HIV entry co-receptor ____, which makes them the PRIMARY TARGETS FOR HIV INFECTION

Answer 14

CCR5

Question 15

Which cells are eliminated rapidly from the gut mucosa during initial HIV infection (leaving the gut susceptible to infections such as CMV)?

Answer 15

CD4 T cells with co-receptor CCR5

Question 16

What is the most commonly used co-receptor during early phase of HIV infection?

Answer 16

CCR5

Question 17

HIV strains using CCR5 as a co-receptor are called __ viruses (these are the strains that are most commonly transmitted sexually)

Answer 17

R5

Question 18

About 5 years into infection, most viruses are able to use the co-receptor _____ . These viruses would now be called “X4” viruses.

Answer 18

CXCR4

Question 19

Three ways that ___ T cells are destroyed following HIV infection:
Cytophathic effects (structural changes that make the cell unable to function properly)
Apoptosis
Killing of infected cells by cytotoxic lymphocytes

Answer 19

CD4

Question 20

In acute HIV infection, there is a rapid rise in plasma viral load and a corresponding rise in ___T cell count which tries to contain the virus.

Answer 20

CD8

Question 21

In the early (first few weeks) stage of HIV infection, CD4 cell counts ____ while CD8 cell counts _____

Answer 21

decrease, increase

Question 22

What are the three mucosal HIV transmission routes?

Answer 22

GU, rectal, and oral mucosa

Question 23

Lamina propria CD4 T-cells express high levels of

Answer 23

CCR5

Question 24

Depletion of CD4 T cell sin the gut leads to increased translocation of gram negative LPS bacteria, which causes generalised immune activation and ___ production

Answer 24

TNF

Question 25

Inflammatory cytokines like ___ drive HIV replication, and with it, CCR5 upregulation

Answer 25

TNF

Question 26

What is the test of choice for HIV?

Answer 26

Combined HIV antibody and HIV p24 ELISA (known as the “4th generation” test). These detect the p24 HIV protein Ag as well as the conventional HIV Abs

Question 27

The time between HIV exposure and when a 4th gen test will identify >99% of infections is known as the _______ period. This is __days according to new guidelines.

Answer 27

window, 45

Question 28

The ________ period is the time between the infection and when the virus RNA becomes detectable in the blood- NO TEST can identify HIV infection before the end of this period.

Answer 28

eclipse (the first 10 days)

Question 29

A further HIV test at __ weeks post-exposure may be considered following an event as carrying a high risk of infection if previous tests were negative

Answer 29

8

Question 30

PCR tests may be used as a confirmation test or if an exposure was very recent. Any test result should be confirmed after __ days using a 4th generation test.

Answer 30

45

Question 31

In the event of a positive HIV test, the same material should be tested again using…

Answer 31

a different test.

If the result confirms the first test, an additional sample should be tested ASAP for confirmation. This should also be done if the second test is negative.

Question 32

Drugs used to treat HIV infection include several different types of ___-_____ drugs such as fusion inhibitors, CCR5 receptor inhibitors, reverse transcriptase inhibitors, integrase inhibitors, and protease inhibitors

Answer 32

anti-retroviral

Question 33

Prescribing a combination of antivirals (usually 3 different classes) is essential due to viral dynamics and …

Answer 33

resistance

Question 34

What is the measure of viral replication?

Answer 34

viral load- the lower the better

Question 35

Viral load marker of tx success: aim for “undetectable” level of …

Answer 35

<40

Question 36

Normal values of CD4+ T cells?

Answer 36

> 500

Question 37

• Significant risk of morbidity/mortality if CD4+ count is

Answer 37

<200

Question 38

When CD4+ count drops below normal (till about 200) the patient is at increased risk of __, Kaposi’s Sarcoma, shingles, oral thrush, and seborrhoeic dermatitis

Answer 38

TB

Question 39

When CD4+ cell count drops below 200, the patient is at increased risk of __________ pneumonia, toxoplasmosis, and lymphoma

Answer 39

Pneumocystis

Question 40

When the CD4+ count drops below __, the patient is at risk of infections such as Mycobacterium Avium Complex, CMV, progressive multifocal leukoencephalopathy infection, and CNS lymphoma

Answer 40

50

Question 41

When people at very high risk of HIV take daily HIV medicines to reduce the chances of getting infected, this is known as

Answer 41

Pre-exposure prophylaxis (or PrEP)

Question 42

The ___ surface protein is used as a primary receptor for HIV entry

Answer 42

CD4

Question 43

Most CD4 T cells in the gut mucosa are highly activated and express the chemokine receptor, ____, an HIV co-receptor

Answer 43

CCR5

Question 44

Viruses using the ____ co-receptor are the most common strains to be sexually transmitted

Answer 44

CCR5

Question 45

____ is an alternative co-receptor (to CCR5)

Answer 45

CXCR4

Question 46

immune activation from___ production, drives viral replication and the progression of HIV infection towards AIDS

Answer 46

TNF

Question 47

A negative 4th gen test at __ days after an exposure is thought to exclude HIV infection with 99% certainty

Answer 47

45

Question 48

Viral Ag levels peak at around __ days after initial infection

Answer 48

28