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Flashcards in HIV Deck (18)
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1

gag

core and matrix proteins; p24

2

env

membrane glycoproteins: gp120 (outer) and gp41 (transmembrane)

3

pol

Reverse transcriptase, protease, and integrase

4

tat

Positive regulator of transcription

5

rev

Allows export of transcripts from the nucleus

6

vif

Affects particle infectivity

7

vpr

Viral protein R. Transport of DNA to nucleus. Augments virion production. Cell cycle arrest.

8

vpu

Viral protein U. Promotes intracellular degradation of CD4 and enhances release of virus from cell membrane.

9

nef

Augments viral replication. Down-regulates CD4 and MHCH

10

What is the major co-receptor for macrophage-tropic strains of HIV?

CCr5

11

What is the major co-receptor for T cell-tropic strains of HIV?

CXCr4

12

Most common strain of HIV in U.S.

HIV-1 Group M Subtype B

13

Properties of Stage I HIV

Acute retroviral syndrome -- highly contagious
30% of patients asymptomatic; others have flu-like symptoms

1. Primary infection of blood, mucosal cells
2. Infection established in lymphoid tissues
3. Acute HIV syndrome, spread throughout body
4. Immune response

14

Properties of Stage II HIV

Clinical latency
Establishment of chronic infection; virus trapped in lymphoid tissues by follicular dendritic cells
Low-level viral replication for several years

15

Properties of Stage III HIV

AIDS
Destruction of lymphoid tissue
Defining opportunistic illnesses

16

Stage 3-Defining Opportunistic Illnesses in HIV infection

Kaposi sarcoma
Candidiasis
CMV
Cryptococcus
Herpes simplex
Lymphoma
Pneumonia

17

Steps of HIV replication

1. Virus binds with CD4 on T cell surface via gp120
2. Binding induces conformational change that opens up site for co-receptor binding (CCr5: T cell / CXCr4: Macrophage)
3. HIV RNA, protease, integrase, and reverse transcriptase enter cell
4. Viral DNA is formed by reverse transcriptase in cytoplasm, then transported across nucleus via protein R, and integrated into host DNA via integrase --> now a provirus
5. New viral RNA is formed from host+viral DNA
6. New RNA transported out of nucleus via tat and and rev
7. New RNA is used to make viral proteins
8. New RNA and proteins move to cell surface and a new, immature HIV forms
9. New virus/proteins mature via protease, are exocytosed

18

What is significant about CXCr4?

Only present on T-cells (CCr5 present on T cells and macrophages). Indicate faster/more severe illness because they provide a second method of entry into host cell.