retroviruses aids and tumor viruses

Question 1

who was part of the 4H group for aids?

Answer 1

homosexual men
haitians
heroine addicts
hemophiliacs

Question 2

how did HIV evolve

Answer 2

Simian virus –>HIV 2 (african heterosexuals) –> HIV1 (4H group)

Question 3

traits of retroviruses

Answer 3

unique replication cycle
ubiquitous in vertebrates
many are benign but some are really pathogenic

Question 4

how do spumaviruses effect humans? what’s an example

Answer 4

benign; make foamy structures in cell

simian foamy virus

Question 5

all retroviruses have similar biology
subfamilies:
genome:
virion:
proteins

Answer 5

subfamilies: spumaviridae and orthoretroviridae
genome: +ssRNA but has 2 identical copies (diploid) and goes through DNA intermediate
virion: enveloped
proteins: reverse transcriptase, integrase, protease

Question 6

replication of retroviruses

Answer 6

attach
enter into nucleus
reverse transcription ssRNA to dsDNA
integration of virus dsDNA into host genome
transcription from provirus
translaton 
assembly, release and maturation

Question 7

what is required for reverse trasnscriptase and what triggers it?

Answer 7

triggered when nucleocapsid is in cytoplasm

needs high levels of NTPs

Question 8

why is it hard to make a vaccine for a retrovirus?

Answer 8

reverse transcription is promiscuous between genome copies so there’s a high level of mutation

Question 9

retrovirus genome integration can cause cancer, what are integration related identified oncogenes?

Answer 9

transcription factors
secreted growth factors
growth factor receptors
cell signal transduction pathways

Question 10

retroviruses require a _____ to make progeny

Answer 10

complementary infection

Question 11

benign retroviruses cause host response due to _______. can host response ever eradicate virus?

Answer 11

viremia (virus in blood)

no eradication from immune response

Question 12

types of pathogenic retroviruses

Answer 12

slow: high levels of mutagenesis and tumorigenesis
cytopathic: carry genes to lyse cell, cause direct tissue damage
acute transforming: carry genes that inhibit apoptosis and stim. replication, causes tumors, often defective b/c replaces essential virus gene with host gene

Question 13

HTLV types, family, transmission

Answer 13

4 types: 1 (human),2,3,4
deltaretrovirus
transmission via body fluid exchange

Question 14

how does HTLV1 spread within a host

Answer 14

cell to cell: it infects a T lymphocyte which contacts and adheres to another T lymphocyte

Question 15

adult T-cell lymphoma/leukemia

Answer 15

type of HTLV -1 disease from mucous exposure
rare
latent 30-50 years
infects memory T cells
antigen activation triggers transcription of provirus
cells transform and generate tumors

Question 16

HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) disease and sympt

Answer 16

type of HTLV-1 disease from transfusions
rare
T cells enter nervous system
sympt start 3 years after exposure
starts w/ bladder control issues 
lower back/leg/hip/knee weakness or pain
men have erectile dysfunction

Question 17

HTLV-1 prevention/treatment

Answer 17

no breastfeeding
screen blood before transfusions
treatment depends on disease
ATLL- chemotherapy
HAM/TSP-corticosteroids/interferon

Question 18

HIV family

Answer 18

lentivirus

Question 19

why did aids incidence go down in 1994?

Answer 19

AZT antiviral treatment introduced

Question 20

HIV disease progression

Answer 20

latent period 6 mo. -25 yrs
targets memory T cells
has flu like symptoms
mucocutaneous ulceration/weight loss are indicative

Question 21

HIV prevention/treatment

Answer 21

screen blood/safe sex
no vaccine
antivirals:
nucleoside revers transcriptase inhibitors (AZT)
protease inhibitors (Ritonavir)
non-nucleoside RT inhibitor (efavirena)
combination of the three