herpes virus and antivirals Flashcards
what’s the genome and virion type for herpes virus? what’s the virion exception?
they’re all dsDNA and enveloped
exception: human papillomavirus is nonenveloped
basics of alpha herpes virus
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
how does alpha herpesvurus latency work?
hangs out in stationary cells and stays as an episome in nucleus.
esp. in peripheral ganglia
comes out again w/ sunburn, stress, immune impairment…
control of herpes virus and herpes response
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
betaherpes characteristics
restricted host range
enlarges cells b/c slow replication
prototypical type: cytomegalovirus
causes latent infections
gammaherpes virus characteristics
prototypical member : epstein-barr virus latent in lymph lytic infections targets T and B lymphocytes restricted host range
Epstein barr virus related carcinomas
burketts lymphoma - tumor in jaw, eye ocket, and ovaries
hodgkins lymphoma
what types of immunity can herpes evade?!?
intrinsic - blocks cell death
innate - decreases NK cell activity
adaptive immunity - decrease antigen presentation and blocks MHC blinding
how are cytomegalovirus and epstein -barr virus diff?
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
beta/gamma virus teatment and prevention
infections self limiting
antiviral therapy : acyclovir limits cell replication - less effective w/ epsein barr
prophylactic treatment
papillomanvirus biology
papillomavirida family
circular dsDNA
non-enveloped
what does papillomavirus look like and what cells does it effect?
warts
attacks basal cells of skin during differentiation process
how does papillomavirus exit a cell?
weakly lytic, waits for cell to die then gets out
what papillomavirus is associated w/ ovarian cancer?
serotypes 16 and 18
human papillomavirus transmission
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
papilloma virus symptoms
warts take months to manifest, but 50% regress on their own in 2 years
can be respiratory which can be lethal
how is HPV similar to adenovirus?
can cause cancer based on E7 blocking retinoblasoma protein promoting cell division or E6 blocking p53 tumor suppression pathway
treatment for HPV
wart removal
no proof condoms work
vaccine- gardasil
antiviral challenges
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
enfurvitide antiviral
for HIV blocks membrane fusion by stoping refolding of gp41 protein
works b/c targets viral protein
amantadine and rimantadine antiviral
blocks influenza ion channel stopping pH change and nucleocapsid release
nucleoside analog antiviral for herpes examples
cause DNA chain to terminate early
acyclovir
ganciclovir - for CMV
valganciclovir - like acyclovir for oral infections
how does acyclovir work?
specifically binds to thymadine kinase and causes DNA chain to terminate early
foscarnet characteristics
prevents viral polymerase activity in herpes
toxic and administed by IV so last ditch effort
nucleoside inhibitors of HIV and HBV traits and example
can be taken orally
toxic
viruses can be resistant (why HIV usually gets a cocktail)
ex: ribovirin
how does ribovirin work/what does it target
triphosphate inhibits polymerase
monophosphate inhibits lowering of GTP
impairs capping of mRNA
how does ritonavir work to treat HIV
blocks cleavage of polypeptide necessary for virus maturation
what stages of viral replication can be blocked
entry uncoating nuc acid synth late prot synth release
natural antiviral
interferon - blocks protein synthesis
active vs. passive immunization
active : part or all of a pathogenic agent given to cause antibody response
passive : antibodies given directly (temporary)
advantages/dis for live attenuated vaccine
live attenuated easy to administer induces cell mediated immunity long lasting but can revert (like polio virus) not safe for immunocompromised people
advantages/dis for killed active vaccines
safe for immuno compromised and can’t revert
but usually injected and doesn’t produce long lasting or cell mediated immunity
vaccine considerations
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
