Exam 3 HIV Retrovirology

Question 1

HIV is part of the ____ family

Answer 1

Lentivirinae

Question 2

Lentivirinae viruses are characterized as:

Answer 2

Slow, neurologic, or immunosuppressive

Question 3

Morphology of HIV capsid

Answer 3

• D-type capsid
• Central, cone shaped cylindrical

Question 4

HIV regulatory genes

Answer 4

• Tat
• Nef
• Vpu

Question 5

Tat function

Answer 5

Transcriptional activator

Question 6

Nef function

Answer 6

Reduces MHC I expression

Question 7

Vpu function

Answer 7

Enhances virion release

Question 8

HIV gp120 binds primary host cell receptor ____ and has a high affinity for binding host co-receptor ____

Answer 8

CD4; CCR5

Question 9

HIV gp120 is _____ (initial)

Answer 9

M-tropic

Question 10

HIV - ____ strains M-tropic; early infection of _____

Answer 10

CCR5 or R5; Macrophages and dendritic cells

Question 11

After M-tropic initial infection, HIV subsequently moves to the ____ and spread to _____. This is termed _____ or later infection

Answer 11

Lymph nodes; CD4 T cells; T-tropic

Question 12

Reverse transcriptase is highly error prone, which causes:

Answer 12

Rapid generation of many new strains (HIV clades and antigenic variants)

Question 13

____ is most common and most pathogenic in the US

Answer 13

HIV-1

Question 14

HIV-1 causes _____ (90% cases in the US)

Answer 14

M-type “major”

Question 15

HIV gp41 facilitates:

Answer 15

• Fusion with macrophages, dendritic cells, microglial cells
• Fusion with T cells R4 strains

Question 16

HIV envelope gp120 binds ____ and co-receptor CCR5 or R5 of _____

Answer 16

Host CD4; Macrophages

Question 17

____ predominates in early (initial) infection

Answer 17

M-tropic

Question 18

HIV envelope gp120 binds host _____ and co-receptor CXCR4 or R4 of _____

Answer 18

T-cell CD$; T-helper cells

Question 19

____ predominates in late infection

Answer 19

T-tropic

Question 20

People with CCR5 delta-32 have:

Answer 20

Partial resistance to R5 strains (M-tropic)

Question 21

Those who have the CCR5 delta-32 gene are _____ that make up ___ of the population

Answer 21

Homozygous mutants; 1%

Question 22

First gene edited embryos altered ____ receptor in vitro

Answer 22

CCR5

Question 23

HIV co-receptor CXCR4 is ____ (structure)

Answer 23

Heptahelical

type of GPCR

Question 24

HIV integration and replication begins with ssRNA (+) genome and uses _____ to create a ____ strand. This is the _____ function

Answer 24

RTase; DNA strand (-); reverse transcription

Question 25

During HIV replication, RTase degrades the RNA strand of the RNA-DNA hybrid. This is termed _____ function

Answer 25

Ribonuclease H function

Question 26

After RNA degradation, RTase creates ______. This is termed the ____ function

Answer 26

complementary DNA strand; DNA polymerase

Question 27

____ splices HIV into host genome to create a provirus

Answer 27

Integrase

Question 28

Once a provirus is created and HIV has gotten into the host genome, _____ transcribes mRNA

Answer 28

Host RNA polymerase

Question 29

HIV early stage events

Answer 29

Integration, provirus

Question 30

HIV late stage events

Answer 30

• Provirus (latency period)
• Host cell activation
• Host RNA polymerase to transcribe genome

Question 31

Transcription factor active in immune response is _____ which binds ___ to activate HTLV or HIV

Answer 31

NFkB; LTR

Question 32

HIV incubation period

Answer 32

1-10 years

Question 33

During the HIV incubation period, ____ > _____

Answer 33

Resting cells > Half life

Question 34

When do antibodies to HIV become detectable?

Answer 34

2 weeks to 2 months

Question 35

CD4+ cells begin to deplete _____ after infection

Answer 35

Months to years

Question 36

When is HIV infection considered AIDS?

Answer 36

Less than 200 cells/microliter

Question 37

When does seroconversion of HIV occur?

Answer 37

2 weeks to 2 months

Question 38

What are the stages of clinical course of HIV infection?

Answer 38

• Stage 1: acute infection, high viral titers
• Stage 2: Sub-clinical infection, low-level replication
• Stage 3: High viral replication

Question 39

During what stage of HIV infection is the AIDS-related complex found (ARC)?

Answer 39

Stage 2

Question 40

What happens during stage 3 of HIV infection?

Answer 40

• CD4 count < 200 cells/microliter
• AIDS

Question 41

What does AIDS stand for?

Answer 41

Acquired immune deficiency syndrome

Question 42

Oral symptoms of HIV infection

Answer 42

• Severe periodontitis (usually acute)
• Oral candidiasis (tongue, palate, tonsils)

Question 43

HIV diagnosis and treatment: lymphocytes are ____

Answer 43

Low (lower than reference range)

Question 44

HIV diagnosis and treatment: HIV involves ______

Answer 44

Destruction of T cells

Question 45

List the steps of HIV pathogenesis (7)

Answer 45

• Loss of T-helper function
• Reduced CD4 cell count
• Immune system failure
• Th1, Th2 function impaired
• Loss of DTH function
• Opportunistic infections
• Unusual neoplasms

Question 46

Infective HIV virions _____ found in whole saliva of patients

Answer 46

Rarely (cannot exist in cell free state in saliva)