Micro Test 3 Epidemiology, Flu, and HIV (Part 3)

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1

Describe HIV in its simplest form.

Enveloped retrovirus

Polyhedral capsid

2 copies +ssRNA

2 tRNA

10-50 copies of : reverse transcriptase, protease, integrase

2

HIV will infect what 4 types of cells?

T helper cells

Cells of the macrophage lineage (monocytes, macrophages, and microglia)

Smooth muscle cells

Dendritic cells (antigen presenting cells in skin, mucosa membranes, and lymph nodes)

3

While HIV does NOT infect B cells, the B cells still play a part in HIV. What do they do?

Deliver HIV to lymphoid tissues where T cells mature

4

An HIV envelope contains two proteins, what are they?

gp120

gp41

5

The protein gp41 promotes what?

Membrane fusion of envelope and cell membrane to allow cell entry

6

The protein gp120 binds to what receptor on the cell?

CD4 receptor

7

The protein gp120 can change its conformation during infection. Why is this a problem?

It makes the antibody recognition difficult

8

HIV attachment and entry occurs in three steps. What are they?

1. Gp120 binds to CD4 receptor on a T cell

2. Gp120-CD4 complex binds to another receptor and causes gp41 to be revealed

3. Envelope and cell membrane can then fuse and allow the capsid to enter.

9

When gp120-CD4 complex binds to another receptor and causes the gp41 to be revealed, what does it interact with in the T cells, macrophages, and smooth muscle cells?

T cells have CXCR4

Macrophages and Smooth muscles have CCR5

10

After the three step process of HIV attachment and entry occurs, the gp41 is left on the membrane. This makes it possible for what to happen?

It makes it possible for neighboring cells to fuse with that cell.

11

When neighboring cells fuse with the gp41 its called what?

syncytium

12

The HIV's dsDNA will incorporate itself into what upon cell entry?

The host cell's DNA

13

Once the dsDNA enters the hosts genome its called what?

Provirus

14

The enzyme responsible for integration is called what?

Integrase

15

True or false:

Provirus can lay dormant for years or be activated immediately.

True

16

RNA transcribed from the provirus can be used to do what?

Translate viral proteins or to be packaged into new virions

17

How does HIV get the envelope from its host cell?

By budding out through the wall

18

An HIV virus is NOT mature or virulent until what happens?

protease cleaves proteins and activates the assembly of the capsid

19

When a person is infected with HIV, there is a burst of viral ________ and release of virus from infected cells.

production

20

Primary infection symptoms of HIV are similar to what other virus?

the flu

21

The immune system will produce antibodies. What will happen to the number of free virions?

they will dramatically decrease and no symptoms are seen at this stage

22

Within the cells, latent infection continues and the virus simply does what?

Replicates

23

While latent infection happens, the virus replicates and is released only to do what?

Infect other cells

24

The infection of other cells during the latent infection of HIV occurs at such a fast rate the body cannot replenish the cells lost. Over 5-10 years the number of ________ cells declines.

T helper

25

What do the T helper cells do?

Antibody regulation

26

If the T helper cells are lost, what is the effect on the body?

The ability to produce antibodies is lost, making it easier for the host to get sick

27

HIV was first recognized in what group of people?

Homosexual males

28

Through what bodily secretions can HIV be transmitted?

blood

semen

saliva

vaginal fluid

breast milk

29

Through what kind of contact can HIV be transmitted?

sex

IV drug use

blood transfusions (rare now days)

organ transplants (rare now days)

tattooing

accidental needle sticks

sharing razors and toothbrushes

across the placenta

30

For an HIV patient to be diagnosed with AIDS the patient must have antibodies against HIV and one or more of what rare diseases?

Candidiasis

shingles

Hairy leukoplakia

pneumocystis pneumonia

histoplasmosis

coccidiomycosis

mycobacterium

Kaposi's scarcoma

toxoplasmosis

31

Most patients, when diagnosed with AIDS, have what unexplained side effects?

Weight loss

fatigue

fever

low CD4 count

32

The treatment of HIV is accomplished by focusing on what?

Multiple areas of viral replication

33

What does HAART stand for?

Highly Active Antiretroviral Therapy

34

What is HAART?

a "cocktail" of nucleoside analogs, protease inhibitors, and reverse transcriptase inhibitors

35

Is HAART a cure?

No, just a treatment

36

To get an HIV vaccine that is effective, it must generate sufficient ________ to prevent sexual transmission and infection.

antibodies

37

HIV can spread through _______ to evade the immune system.

Syncytia

38

What is a long term non-progressor?

A person who is chronically infected with HIV but has not developed AIDS

39

What three possible ways do long term non-progressors keep from developing AIDS?

Infected with defective virions

They lack effective co-receptors (CXCR4/CCR5)

Have an unusually well developed immune system

40

What is the possible HIV cure that is currently being studied?

Bone marrow transplants replacing the infected immune cells with donor cells that have non-functional CCR5 co-receptors