Antivirals Flashcards
Name some viruses that cause acute infection
influenza, measles, mumps, hep A
Why are some virus infections chronic?
If they’re DNA viruses (DNA can survive longer than RNA)
What are the 2 main features of a virus?
nucleic acid and protein coat
What is meant by obligate intracelliular parasites?
chemical structures that can only replicate inside cells
What are the 8 stages of virus replication?
- virus attachment to cell
- cell entry
- virus uncoating
- early proteins produced
- replication
- late transcription/translation
- virus assemble
- virus release
What are targets for antiviral activity@?
unique proteins
Most anitvirals are based on what structure?
polymerases
what drug was found to inhibit HIV replication in 1985?
azidothymidine (AZT)
By what action does AZT inhibit HIV replication?
nucleoside reverse transcriptase inhibitor (NRTI)
What was the problem with NRTIs initially?
resistance very rapidly developed and disease would return within a few weeks
Name 2 NRTIs that are active against HBV and HIV?
lamivudine and tenofovir
Why are protease inhibitors not toxic?
Because viruses create their own unique proteases so these can be targeted, sparing the host
How must fusion inhibitors be administered?
IM
What od chemokine receptor antagonists do?
prevents entry of virus
Why are as many as 3 drugs needed to overcome viruses?
Because they develop resistance so easily
When is HIV treatment started?
After CD4 falls (now evidence suggests should start straight away for everyone)
Approximately how many nucleotides does a HIV genome contain?
about 9,000
When will a strain become predominant?
If it has a selection advantage over fellow progeny
M184C mutation results in resistance to what?
Lamivudine
What are stem-cells reconstituted with?
HLA-matched but delta 32 homozygous allogeneic donor
How are exisiting CD4 lymphocytes destroyed?
conditioning
How do antivirals work?
by blocking a stage of viral replication
