HIV

Question 1

HIV

Answer 1

Diploid: Carries two copies of (+) stranded RNA

Question 2

RNA is tightly bound to

Answer 2

key enzymes

• Reverse Transcriptase
• Aspartate Protease
• Integrase

Question 3

Reverse Transcriptase

Answer 3

Makes RNA from DNA

Question 4

Aspartate Protease

Answer 4

Cleavage of proteins

Question 5

Integrase

Answer 5

Integrates DNA into host cell DNA

Question 6

HIV shape

Answer 6

Conical capsid

Question 7

HIV is composed of

Answer 7

multiple copies of nonvariable, p24 protein

Question 8

Does immune system produce antibodies to HIV?

Answer 8

Yes, but they are not strong enough to neutralize virus

Question 9

HIV envelope made of

Answer 9

phospholipids from human cell membrane

Question 10

What protein does the envelop contain?

Answer 10

env

Question 11

Cap of env protein contains

Answer 11

glycoproteins (gp120 and gp41)

Question 12

gp120

Answer 12

attachment to T cells

Question 13

gp41

Answer 13

fusion and entry into T-cells

Question 14

gp120 and gp41 are both formed as a

Answer 14

single protein (gp160) and cleaved

Question 15

Gene for gp 120 mutates

Answer 15

rapidly (antigenic variation)

Question 16

V3 loop portion of gp120

Answer 16

highly immunogenic
so varies significantly
and antibody neutralization difficult

Question 17

Antibodies develop against what portion of gp 120?

Answer 17

V3 loop

Question 18

3 main genes encode HIV virus

Answer 18

Gag
Pol
Env

Question 19

Gag gene encodes

Answer 19

nucleocapsid (p24)

Question 20

Pol gene encodes

Answer 20

polymerase

• reverse transcriptase
• integrase
• protease

Question 21

Env gene encodes

Answer 21

envelope proteins

-gp120: gp120+gp41

Question 22

Tat and Rev genes required for

Answer 22

viral replication

Question 23

tat

Answer 23

activates gene transcription

Question 24

rev

Answer 24

transports mRNA from nucleus to cytoplasm

Question 25

Auxillary genes

Answer 25

Nef, viv, vpr, vpu, vpx

-Not required for replication (auxillary)

Question 26

Nef

Answer 26

decrease CD4 proteins and MHC-I on T-Cell surfaces

Question 27

Major lymphocyte receptors used by HIV to enter cells

Answer 27

CCR5 and CXCR4

Question 28

CCR5-tropic viruses

Answer 28

Replicate in monocytes/macrophages (M-tropic)
Can also infect dendritic cells (trafficking to lymph nodes)
Occur early: sexually transmitted to macrophages

Question 29

CXCR-tropic viruses

Answer 29

Replicate more efficiently in T-cells (T-tropic)

Occur later after infection has developed

Question 30

Mutations to CCR5 gene associated with

Answer 30

decreased susceptibility to HIV infection

Question 31

Which drug class does not work in HIV-2?

Answer 31

NNRTIs

Question 32

Presentation of acute HIV syndrome often confused with

Answer 32

mononucleosis (EBV)

Question 33

ELISA

Answer 33

Tests for antibody only. Sensitive but many false positives. Western blot used to confirm positive ELISA (specific).

Question 34

4th generation tests

Answer 34

Combination tests for p24 antigen and HIV antibodies

If positive, antibody differentiation assay

Question 35

Acute HIV

Answer 35

p24 and HIV antibodies are not generated yet but you can test for viral load (HIV RNA)

Question 36

HIV PCR testing used for babies b/c

Answer 36

HIV antibodies from mother may exist for months

Question 37

Pneumocystis Pneumonia

Answer 37

CD4<200

TMP-SMX

Question 38

Pneumocystis and Toxic Plasmosis

Answer 38

CD4<100

TMP-SMX

Question 39

Histoplasmosis (endemic areas)

Answer 39

CD4<100

Itroconazole

Question 40

Mycobacterium Avium Complex

Answer 40

CD4<50

Azithromycin