HIV

Question 1

What does HIV stand for?

Answer 1

Human Immunodeficiency Virus

Question 2

What are the 2 types of HIV?

Answer 2

HIV-1: worldwide, more transmissable
HIV-2: West Africa (mostly)

Question 3

What is the host cell specificity of HIV?

Answer 3

Th lymphocytes and macrophages

Question 4

What are the viral proteins of HIV?

Answer 4

gp120 and gp41

Question 5

What are the two host co-receptors?

Answer 5

CD4 (always) and either CXCR4 or CCR5

Question 6

What causes the mortality of HIV?

Answer 6

-loss of cell-mediated immune responses
-opportunistic secondary infections

Question 7

When was HIV/AIDS first reported?

Answer 7

1981

Question 8

Where was HIV first reported?

Answer 8

metropolitan area in the US and Europe

Question 9

What is the genome of HIV?

Answer 9

2 strands of positive single stranded RNA: diploid

Question 10

What are retroviruses?

Answer 10

use RNA-dependent DNA polymerase (reverse transcriptase) to produce double stranded DNA from a viral genome having 2 copies of single-stranded RNA

Question 11

How many total genes are in HIV?

Answer 11

9

Question 12

What are the 3 structural genes of HIV?

Answer 12

gag
pol
env

Question 13

What does gag encode?

Answer 13

capsid proteins (p24) and matrix proteins (p17)

Question 14

What does pol encode?

Answer 14

reverse transcriptase
integrase
protease

Question 15

What does env encode?

Answer 15

spike proteins; gp120 and gp41

Question 16

What is the function of spike proteins?

Answer 16

They are needed to bind to host cell receptors

Question 17

What are the 4 accessory genes of HIV?

Answer 17

nef
vif
vpu
vpr

Question 18

What does nef do?

Answer 18

represses host MHC (tells host not to express MHC-1)

Question 19

What does vpu do ?

Answer 19

destroys CD4 protein of host cell (need CD4 to let virus in- stops immune system from binding to CD4)

Question 20

What does vif do?

Answer 20

inactivates cell defense

Question 21

What does vpr do?

Answer 21

transports HIV genome to nucleus

Question 22

What are the significant HIV proteins?

Answer 22

outside virion and inside virion

Question 23

What is outside virion?

Answer 23

spike proteins enable binding to hos co-receptors (CD4)
INCLUDES gp120- highly variable & gp41

Question 24

What is an inside virion?

Answer 24

Enzyme, RNA-dependent DNA polymerase (RT)
Enzyme, Integrase
Enzyme, Protease

Question 25

What are the two types of ELISA?

Answer 25

Direct and Indirect

Question 26

What is direct ELISA?

Answer 26

Looking for antigen in the sample

Question 27

What is indirect ELISA?

Answer 27

looking for antibodies vs specific antigens

Question 28

True or False: ELISA is not sensitive

Answer 28

False- ELISA is very sensitive

Question 29

True or False: ELISA can't detect low amounts of antigens or antibodies

Answer 29

False- ELISA can detect low amounts of antigens and antibodies

Question 30

What is genetic instability?

Answer 30

extremely high rates of mutation (an error- prone to reverse transcriptase)

Question 31

True or False: Recombination occurs among HIV subtypes

Answer 31

True

Question 32

How does HIV evolve in the host?

Answer 32

Starts as one strand of HIV and progresses to many

Question 33

What changes happen in the evolution of HIV in the host?

Answer 33

host cell tropism drug resistance evasion of immune defenses difficulties with creating potential vaccines (due to changes in antigens)

Question 34

What are the steps of the HIV replicative cycle?

Answer 34

attachment penetration uncoating biosynthesis maturation release

Question 35

What happens in the biosynthesis phase?

Answer 35

reverse transcription using RT migration to nucleus and integration using integrase normal transcription to make 2x +ssRNA Processing of precursor polypeptide using protease

Question 36

What are different HIV treatment strategies?

Answer 36

Inhibit reverse transcriptase Inhibit protease HAART

Question 37

What is HAART?

Answer 37

Highly Active Anti-Retroviral Therapy -"AIDS cocktail" (3 or more drugs in combination) Track response (CD4) & VIRAL LOAD Not a cure

Question 38

What is anti-retroviral therapy?

Answer 38

evaluate treatment via.... CD4+ lymphocytes & viral load -avoids selection of resistant viral strands

Question 39

What are the treatment problems of Anti-retroviral therapy?

Answer 39

complex & individual regimens patient tolerance of drugs drugs expense no vaccine/no cure

Question 40

What is the Immune system avoidance?

Answer 40

-mutation & recombination (antigenic variation) -antibodies neutralize but are not protective -integration of viral DNA into host chromosome

Question 41

What is the suppression of host immune responses?

Answer 41

hef proteins -> decrease MHC-1 expression -> lower Tc function -> suppressed cell-mediated immunity -> fewer HIV infected cells killed