Retroviruses Flashcards Preview

MCIM 309 > Retroviruses > Flashcards

Flashcards in Retroviruses Deck (21):
1

Genome

Enveloped +RNA
encode RNA-dependent DNA polymerase (reverse transcriptase[RT])

2

subfamilies

-Oncovirinae (HTLV-1,2,5); Cancer, neurological disorder
-Lentivirinae (HIV-1, HIV-2); slow, neurological disorders, immunosuppression
-Spumvirinae; nothing
-Endogenous viruses; retrovirus sequences that are integrated in the human genome (up to 8%)

3

Structure

enveloped
spherical
8-120 nm

4

genome feature

2 identical copies of +RNA

5

HIV virion structure

Truncated cone

6

HIV Attachment

Binds CD4 on T cells
also binds CCR5 on certain T cells
Fusion though gp41

7

HIV Early Phase Replication

entry by fusion, genome release
RT makes complementary -DNA, then synthesizes +DNA, enters nucleus and is integrated into host genome by intergrase

8

HIV Late Phase Replication

Full length RNA produced, which then makes mRNAs and proteins for new virion.
Envelopment and release at plasma membrane or through syncytia. HIV does not have to kill cell. requires cleavage of Gag and Gag-Pol

9

HIV-1 genotypes

M (most common)
N
O
P

10

HIV evasion tactics

infection of Lymphocytes and Macrophages (inactivates key parts of immune defense)
CD4 T cell infection (syncytia,apoptosis, loss of activation and control of immune system)
Antigenic Drift
Direct cell to cell spread

11

3 Stages

1: Acute infection: resembles flu + rash
2: Persistence: Chronic Lymphadenopathy +fever, weight loss, fatigue
3:Reduction in CD4 T Cells <500/uL (increased virus in blood)

12

After Stage 3?

FULL-BLOWN AIDS
CD4 T Cell count <200/uL
Virus load >75,000 copies/mL

13

Oppurtunistic infections

Th17 depletion leads to fungal and bacterial infection
Th1 depletion leads to viral and intracellular bacterial infections

14

Clinical syndromes

one of the most devastating epidemics ever.
HIV progresses from asymptomatic to profound immunosuppression called "AIDS"
-oppurtunistic infections
-cancers
-direct effect of HIV on CNS

15

Transmission

Blood
Sex
Perinatal

16

At risk?

Drug users, many partner sex, prostitutes, newborns of infected mothers, blood and organ transplant pre-1985

17

Diagnosis

ELISA, western blot, Virion RNA RT-PCR, Real-time RT-PCR, CD4 cell counts + CD4:CD8

18

Treatment

Many Many options, combinations for less chance of resistance.

Highly Active Antiretroviral Therapy very important

19

prevention

education on safe sex, blood +organ donation screening, antiviral drugs, sterile needles.

20

Vaccine difficulty

primary targets are different between clades and species.

21

Vaccine developement

-Prime T cell response via vaccinia, canarypox, defective adenovirus vectors containing gp160 (env) gene (DNA vaccine). protein gp120/160 to activate B cells.