Antivirals and Vaccines Flashcards
Why are drugs hard to inhibit?
-most drugs work against enzymes and viruses use host machinery to replicate so there are few enzymes to target
What are 2 common enzymes used by viruses?
- Protease –> HIV, (+)ssRNA
- Polymerase–>Viral
True or false: Protease can be a target for all viruses
False
-(-)ssRNA do not have protease since they do not make polyproteins so they cannot be targeted
True or false: Viral polymerase is a target by all viruses
False
-Not all viruses use viral polymerase (Papilloma and Polyoma use host polymerase)
Why are viruses hard to drug
-Mutate a lot
-Need to target a virus at multiple locations to avoid resistance
What are host targets to stop HIV?
-Tetherin
-TRIM5a
-APOBEC3
-SAMHD1
What are drug targets to stop HIV?
-Fusion inhibitors
-CCRs inhibitors
-NRTIs
-NNRTIs
-INSTIs
-Protease inhibitor
How do we currently inhibit viruses?
Most drugs target VIRAL polymerase
1. Prodrug is used to enter membranes (not active and is not recognized by polymerase)
2. Once prodrug passes through membrane it is converted to active compound through phosphorylation (viral pol recognizes it more than host)
3. Blocks polymerase activity as chain terminator (can no longer replicate)
What are the differences between Nucleoside reverse transcriptase (NRTI), Non-nucleoside reverse transcriptase inhibitor(NNRTI), and Nucleoside Analog (Ribavirin)?
NRTI: Chain terminator for HIV
NNRTI: Binds to reverse transcriptase and stops function
Nucleoside: Get added as a nucleotide–>causes mutations in pol and error catastrophe
Besides proteases what are some other enzyme targets by drugs?
-Neuraminidase (Influenza)
-Integrase (HIV)
-Vp1 (Picorna)
-Interferon
-Paxlovid (Corona)
Because viruses mutate so quickly how do we combat this?
-Combine a mixture of drugs (drug cocktai)
-target multiple things in virus
What is the drug used in HIV?
HAART (Highly Active Antiretroviral Therapy)
Targets–> Pol (NTRI & NNTRI), Protease, Integrase
Ways to prevent HIV spread?
-No vaccine instead antiviral drugs are used
-HIV PrEP
What is HIV PrEP?
A preventative measure
-Pre-exposure, prevents infection from happening
-given to mothers during pregnancy to prevent baby from getting HIV
-Given to sex workers/people who may be exposed
True or false: Antivirals work well in acute viruses
False
-wells work in LATENT viruses (HIV, HepC, some herpes)
-Acute viruses replicate too fast, body normally clears infection
