Anti-virals Flashcards
What surrounds the genetic material in viruses? What may surround this?
Capsid (protein shell)
Surrounded by a lipid envelope which contains envelope proteins.
What type of genetic material do the following viruses have:
a. Hepatitis B
b. Hepatits C
c. HIV
d. Herpes Simplex Virus
e. Influenza
a. Hepatitis B Hepadnavirus – it is a DNA virus that also involves reverse transcriptase in its replication b. Hepatitis C RNA virus c. HIV Retrovirus d. Herpes Simplex Virus DNA virus e. Influenza RNA virus
Describe the relative curability of Hep B and Hep C.
Hep B – not curable
Hep C – CURABLE
At what point do you start treating someone who has recently got infected by Hep B or Hep C?
When the infection becomes chronic
The immune system, in some people, is able to clear Hep B and Hep C infections by itself
What is the treatment for Hep B? What type of drug is this? What is it sometimes given with?
Tenofovir
= Nucleotide analogue which inhibits the activity of reverse transcriptase
- given sometimes with Peginterferon alfa
What are the treatment options for Hep C? State the drug types.
- Ribavirin & Peginterferon alfa
= Ribavirin is a nucleoside analogue (purine analogue) which prevents RNA synthesis - Boceprivir = protease inhibitor (only works on Hep C genotype 1)
In the treatment of HCV today, the specific drugs and the duration of treatment depend on what factors?
- HCV genotype (genetic structure of the virus)
- viral load
- past treatment experience
- degree of liver damage
- ability to tolerate the prescribed treatment
- need for liver transplant
HIV life cycle;
Attachment & Entry
- Viral membrane proteins interact with leukocyte membrane receptors
- Viral capsid endocytosis
HIV life cycle;
Replication & Integration
Within cytoplasm - reverse transciptase enzyme converts viral RNA => DNA
DNA transported into nucleus & integrated into host DNA
HIV life cycle;
Assembly & Release
Host cell’s ‘machinery’ utilised to produce viral RNA & essential proteins
Virus is assembled within cell => mature virion is released
Describe the receptor interaction involved in HIV attachment and entry.
- HIV Glycoprotein (GP)120 attaches to CD4 receptor
- GP120 also binds to either CCR5 or CXCR4
- GP41 penetrates host cell membrane & viral capsid enters
State two drugs that interfere with HIV attachment and entry and state their targets.
Enfuvirtide
= Binds to HIV GP41 transmembrane glycoprotein
Maraviroc
= Blocks CCR5 chemokine receptor
What are the three drug classes which interfere with HIV replication?
Nucleoside RT inhibitors
Nucleotide RT inhibitors
Non-nucleoside RT inhibitors
Name a nucleoside reverse transcriptase inhibitor. How are they activated?
Zidovudine
Three step phosphorylation
Name a nucleotide reverse transcriptase inhibitor. Activation?
Tenofovir
Fewer phosphorylation steps required
