WBCs

Question 1

What is CCR5

Answer 1

A protein on the surface of white blood cells that is involved in the immune system (acts as a receptor for chemokines)

Question 2

Many forms of HIV initially use what to enter and infect host cells

Answer 2

CCR5

Question 3

What is CXCR4

Answer 3

An alpha-chemokine receptor specific for stromal-derived-factor-1, a molecule endowed with potent chemotactic activity for lymphocytes.

Question 4

This receptor is one of several chemokine receptors that HIV can use to infect CD4+ T cells. HIV isolates that use this receptor are traditionally known as T-cell tropic isolates. Typically, these viruses are found late in infection. It is unclear as to whether the emergence of HIV that uses this receptor is a consequence or a cause of immunodeficiency.

Answer 4

CXCR4

Question 5

What is CD4

Answer 5

A glycoprotein found on the surface of immune cells such as T helper cells, monocytes, macrophages, and dendritic cells.

Question 6

The most common and pathogenic strain of the HIV

Answer 6

HIV-1 (class D retrovirus)

Question 7

Form of HIV that has not been widely seen outside of Africa

Answer 7

HIV-2 (class D retrovirus)

Question 8

A virus that has been implicated in several kinds of diseases including myelopathy, Strongyloides stercoralis hyper-infection, and a virus cancer link for leukemia

Answer 8

HTLV-1 (class C retrovirus)

Question 9

Has not been clearly linked to any disease, but has been associated with several cases of myelopathy/tropical spastic paraparesis-like neurological disease.

Answer 9

HTLV-2 (class C retrovirus)

Question 10

P24

Answer 10

A component of the HIV particle capsid. There are approximately 2000 molecules per virus particle

Question 11

provirus

Answer 11

A virus genome that is integrated into the DNA of a host cell

Question 12

A large group or cloud of related genotypes that exist in an environment of high mutation rate, where a large fraction of offspring are expected to contain one or more mutations relative to the parent.

Answer 12

quasispecies

Question 13

This is a part or region of the Human Immunodeficiency Virus that allows it to infect human immune cells by binding to a cytokine receptor on the target human immune cell (CCR5 cell or CXCR4 cell depending on the strain of HIV)

Answer 13

gp120 (V3 loop?)

Question 14

Causes human T-cell leukemia/lymphoma (ATL) through infection and transformation of T lymphocytes.

Answer 14

HTLV -I (class C retrovirus)

Question 15

MOA: HTLV -I (class C retrovirus)

Answer 15

Production of viral protein (TAX) which increases transcription from viral promoter (LTR) as well as from some cellular genes

Question 16

Transmission: sexual, contaminated blood products and maternal-fetal (perinatal; breast milk). latent period of at least 30 years.

Answer 16

HTLV -I (class C retrovirus)

Question 17

A shorter more aggressive clinical course. high white blood cell counts with malignant appearing cells, frequent skin lesions, hepatosplenomegaly, lymphadenopathy, lytic bone lesions. Caused by HTLV -I

Answer 17

Acute Adult T-cell Lymphoma (ATL)

Question 18

Tropical Spastic Paraparesis (HTLV associated myelopathy)

Answer 18

Progressive destruction in spinal cord. Pathogenesis believed to be associated with chronic inflammatory response

Question 19

Insidious onset usually in males > 50 years; prognosis of 3-5 years; infiltration of bone marrow and spleen by disease-specific cells of either T or B cell origin. Patients have severe pancytopenia, massive splenomegaly, and infections; death related to infection or consequences of organ infiltration.

Answer 19

Hairy-cell leukemia

Question 20

Hairy-cell leukemia has equivocal ties to what

Answer 20

HTLV-2 (class C retrovirus)

Question 21

Transmission: HIV

Answer 21

Primarily through internal exposure to body fluids or secretions carrying released virus or cell-associated virus. High risk fluids include semen and vaginal/cervical secretions, blood, plasma/serum, breast milk. may take between 1-2 weeks to establishinfection

Question 22

T-helper lymphocytes that become infected with virus will support virus replication and will be lysed. Monocytes/macrophages, Langerhans cells, dendritic follicle cells will take up virus. Not all strains of virus will replicate in these cells. Cells that don’t support viral replication may act as reservoirs and disseminate the virus.

Answer 22

HIV (class D retrovirus)

Question 23

Infected can develop ATL (1-4% of infected) or HAM/TSP (1-4% of infected). May also be associated with immunosuppression during co-infection with S. stercoralis

Answer 23

HTLV-1 (class C retrovirus)

Question 24

Usually very long incubation time until disease. Transformed CD4+, CD8- T-cells predominantly. Also transforms B cell and bone marrow precursors. Acute onset is more severe. Risk is higher in men

Answer 24

Adult T-cell leukemia/lymphoma (ATL)

Question 25

Incidence is higher in women. Onset around 40 yrs from exposure to disease. Progressive degeneration of spinal cord (T region). Faster progression to paralysis in older people. Disease may be immune-mediated. Caused by HTLV-1

Answer 25

Tropical Spastic Paraparesis (HTLV associated myelopathy)

Question 26

What binds CD4, triggering a conformational change that draws the HIV virus closer to the surface of the cell

Answer 26

Gp120 (V3 loop?)

Question 27

Once gp120 has bound CD4, what binds to CCR5 or CXCR4 to facilitate HIV entry into the cell

Answer 27

Again Gp120 (V3 loop?)

Question 28

What facilitates fusion of the HIV virus and the cell

Answer 28

The peptide portion of the gp41 stalk

Question 29

In order for HIV to gain entry to a cell, what must be on that cell's surface

Answer 29

CD4 and a co-receptor (CCR5 or CXCR4)

Question 30

CCR5 is commonly found on what cells

Answer 30

Cells with a macrophage or dendritic origin and usually found on mucosal surfaces

Question 31

CXCR4 is commonly found on what cells

Answer 31

Lymphocytes

Question 32

Which HIV virus will infect CD4-CCR5 cells

Answer 32

M-tropic virus

Question 33

Which HIV virus will infect CD4-CXCR4 cells

Answer 33

T-tropic virus

Question 34

Acute stage HIV infection

Answer 34

Rash. Peak virus replication. Establishment of reservoirs (first reservoir is gut lymphoid tissue)

Question 35

Intermediate stage HIV infection

Answer 35

8-9 yr period. Low levels of virus replication. Known as clinical latency

Question 36

Late stage HIV infection

Answer 36

When most people get diagnosed. Severe drop in CD4 count

Question 37

Infected individual carries many variants of virus because

Answer 37

HIV reverse transcriptase is very error prone

Question 38

What 2 key proteins are found on the surface of HIV

Answer 38

The fusion protein gp41 (transmembrane component) and surface attachment protein gp120 (extracellular component) are located on the HIV envelope.

Question 39

What is P17

Answer 39

The HIV matrix protein

Question 40

What is p24

Answer 40

The HIV capsid protein

Question 41

What is located inside the capsid of the HIV virus

Answer 41

2 identical RNA copies of the genome with nucleocapsid proteins attached

Question 42

Type D viruses

Answer 42

Have a cone shaped capsid/core structure (HIV-1&2)

Question 43

Type C viruses

Answer 43

Have a hexagonal capsid/core structure (HTLV-1&2)