Chapter 26: Retroviridae, HIV, and AIDS Flashcards Preview

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Flashcards in Chapter 26: Retroviridae, HIV, and AIDS Deck (21):
1

Contact inhibiton

Normal cells, when growing on a plate, will form a single layer and stop dividing when they touch each other

Malignant cells lose contact inhibition and pile up

2

Rous sarcoma virus

Acute transforming virus - carries intact oncogene within viral genome
ONLY known acute transforming virus that is non-defective andhas full RNA genome needed for replication

Src encodes Transmembrane protein that phosphorylates tyrosine ten times the normal rate

It is a retrovirus

3

HTLV-1

Linked to paralytic disease: tropical spastic paraparesis
Induces leukemia

4

Describe HIV structure

Sperical enveloped virion with central cylindrical nucleocapsid
Virion core: 2 identical SS RNA pieces
NC proteins bound to RNA
3 enzymes: protease, reverse transcriptase and integrase

p24-capsid shell
surface glycoproteins: gp120 gp41

5

nef

crucial to HIV virulence and evasion of the host immune system
Downregulates expression of both and CD4 and MHC class I

6

vif

blocks the effects of APOBEC3 enzyme

7

APOBEC3

break down newly synthesized viral DNA

8

In order for fusion and translocation of HIV across the cell membrane what must happen

CD4 binds gp 160
and coreceptor CCR5 or CXCR4 (helper T cells and Mo)

9

If pts fail to produce normal levels of CCR5 what happens?

appears to be resistant to HIV infection

10

What are the stages of HIV?

1. acute viral illness: viremia, symptoms like mononucleosis, 1 month after exposure
2. Clinical latency: 8 years, no symptoms, steady gradual destruction of CD4 T cells
3. AIDS: 2 years then death, Opportunistic infection,

11

Viral load

High levels correlates with a greater risk of opportunistic infection
Tells you the speed of the train
*CD4 count tells you where the train currently is

12

Multinucleated giant cells

T-cell to T-cell fusion allows virus to pass from infected cell to uninfected cell without contacting blood and protects from antibodies

13

B-cells and HIV

Polyclonal activation
Hypergammaglobulinemia
Diminished ability to produce antibodies in response to new antigens or immunizations

14

Monocytes and Mo and HIV

Serve as reservoirs for HIV as it replicates, protects from immune system

Migrate across BBB carrying HIV to CNS

15

What malignancies do AIDS pts often suffer from?

B-cell lymphoma: EPV
Kaposi's sarcoma: HHV-8, lesions red to purple, plaques or nodules and arise on skin all over the body

16

What bacterial and mycobacterial infections do HIV pts often suffer from?

Streptococcus pneumoniae
Mycobacterium tuberculosis
Mycobacterium avium-intracellulare (MAI): non tuberculous mycobacterium, smoldering

17

What fungal infections do AIDS pts often suffer from?

Candida albicans
Cryptococcus neoformans: cryptococcal meningitis, fever no Kernigs
Histoplasma capsulatum
Coccidioides immitis
Pneumocystis jiroveci penumonia (MOST COMMON)

18

What is the most common opportunistic infection in the U.S among pts with AIDS?

Pneumocystis jiroveci pneumonia

19

What viral infections do AIDS pts often suffer from?

Herpes zoster: shingles
EBV: oral hair leukoplakia (hairlike projections arising from side of tongue), B-cell lymphoma
Herpes simplex
Cytomegalovirus

20

What protozoal infections do AIDS pts often suffer from?

Toxoplasma gondii: mass lesions in the brain
Cryptosporidium
Microsporidia
Isospora belli (#1 cause of diarrhea in AIDS pts)
- diarrhea

21

How to diagnose HIV

ELISA: detects Abs, sensitive but gives false positive results
then Western blot test

PCR for early weeks of infectivity