herpes virus and antivirals

Question 1

what’s the genome and virion type for herpes virus? what’s the virion exception?

Answer 1

they’re all dsDNA and enveloped

exception: human papillomavirus is nonenveloped

Question 2

basics of alpha herpes virus

Answer 2

cytopathic 
can cause latent infection
range of hosts
short reproduction cycle
has type 1 (above waist) and type 2 (below waist) diseases
mucosa and skin cells are succepible

Question 3

how does alpha herpesvurus latency work?

Answer 3

hangs out in stationary cells and stays as an episome in nucleus.
esp. in peripheral ganglia
comes out again w/ sunburn, stress, immune impairment…

Question 4

control of herpes virus and herpes response

Answer 4

cell mediated immunity
avoid contact w/ herpes sores
can use acyclovir to limit virus replication but doesn’t affect latent infections
herpes try to bind antibodies and complements

Question 5

betaherpes characteristics

Answer 5

restricted host range
enlarges cells b/c slow replication
prototypical type: cytomegalovirus
causes latent infections

Question 6

gammaherpes virus characteristics

Answer 6

prototypical member : epstein-barr virus
latent in lymph 
lytic infections
targets T and B lymphocytes 
restricted host range

Question 7

Epstein barr virus related carcinomas

Answer 7

burketts lymphoma - tumor in jaw, eye ocket, and ovaries

hodgkins lymphoma

Question 8

what types of immunity can herpes evade?!?

Answer 8

intrinsic - blocks cell death
innate - decreases NK cell activity
adaptive immunity - decrease antigen presentation and blocks MHC blinding

Question 9

how are cytomegalovirus and epstein -barr virus diff?

Answer 9

beta vs. gamma herpes
CMV infection persists in cells but can be controlled by healthy immune syst; doen’t go latent
EBV persists in memory cells; does go latent

Question 10

beta/gamma virus teatment and prevention

Answer 10

infections self limiting
antiviral therapy : acyclovir limits cell replication - less effective w/ epsein barr
prophylactic treatment

Question 11

papillomanvirus biology

Answer 11

papillomavirida family
circular dsDNA
non-enveloped

Question 12

what does papillomavirus look like and what cells does it effect?

Answer 12

warts

attacks basal cells of skin during differentiation process

Question 13

how does papillomavirus exit a cell?

Answer 13

weakly lytic, waits for cell to die then gets out

Question 14

what papillomavirus is associated w/ ovarian cancer?

Answer 14

serotypes 16 and 18

Question 15

human papillomavirus transmission

Answer 15

skin to skin/fomite contact
skin must have a lesion to be entered
it is hearty though so it can survive on a fomite for a while

Question 16

papilloma virus symptoms

Answer 16

warts take months to manifest, but 50% regress on their own in 2 years
can be respiratory which can be lethal

Question 17

how is HPV similar to adenovirus?

Answer 17

can cause cancer based on E7 blocking retinoblasoma protein promoting cell division or E6 blocking p53 tumor suppression pathway

Question 18

treatment for HPV

Answer 18

wart removal
no proof condoms work
vaccine- gardasil

Question 19

antiviral challenges

Answer 19

specificity: must be active against virus but not ourselves
viruses mutate quickly
bioavailability: needs to get to site of infection
toxicity: want it to have a low impact on the patient

Question 20

enfurvitide antiviral

Answer 20

for HIV blocks membrane fusion by stoping refolding of gp41 protein
works b/c targets viral protein

Question 21

amantadine and rimantadine antiviral

Answer 21

blocks influenza ion channel stopping pH change and nucleocapsid release

Question 22

nucleoside analog antiviral for herpes examples

Answer 22

cause DNA chain to terminate early
acyclovir
ganciclovir - for CMV
valganciclovir - like acyclovir for oral infections

Question 23

how does acyclovir work?

Answer 23

specifically binds to thymadine kinase and causes DNA chain to terminate early

Question 24

foscarnet characteristics

Answer 24

prevents viral polymerase activity in herpes

toxic and administed by IV so last ditch effort

Question 25

nucleoside inhibitors of HIV and HBV traits and example

Answer 25

can be taken orally
toxic
viruses can be resistant (why HIV usually gets a cocktail)
ex: ribovirin

Question 26

how does ribovirin work/what does it target

Answer 26

triphosphate inhibits polymerase
monophosphate inhibits lowering of GTP
impairs capping of mRNA

Question 27

how does ritonavir work to treat HIV

Answer 27

blocks cleavage of polypeptide necessary for virus maturation

Question 28

what stages of viral replication can be blocked

Answer 28

entry
uncoating 
nuc acid synth
late prot synth
release

Question 29

natural antiviral

Answer 29

interferon - blocks protein synthesis

Question 30

active vs. passive immunization

Answer 30

active : part or all of a pathogenic agent given to cause antibody response
passive : antibodies given directly (temporary)

Question 31

advantages/dis for live attenuated vaccine

Answer 31

live attenuated easy to administer 
induces cell mediated immunity 
long lasting 
but can revert (like polio virus)
not safe for immunocompromised people

Question 32

advantages/dis for killed active vaccines

Answer 32

safe for immuno compromised and can’t revert

but usually injected and doesn’t produce long lasting or cell mediated immunity

Question 33

vaccine considerations

Answer 33

age: young and elderly have weak immune syst. so might not be able to handle live attenuated active vaccine
special populations/immunocompromised need a killed vaccine or special considerations