Antivirals

Question 1

What surrounds the genetic material in viruses?

Answer 1

Capsid (protein shell)

Question 2

What type of genetic material do the following viruses have:

a. Hepatitis B
b. Hepatits C
c. HIV
d. Herpes Simplex Virus
e. Influenza

Answer 2

Hepatitis B: DNA virus that involves reverse transcriptase in its replication 
Hepatitis C: RNA virus 
HIV: Retrovirus 
Herpes Simplex Virus: DNA virus 
Influenza: RNA virus

Question 3

Describe the relative curability of Hep B and Hep C.

Answer 3

Hep B: not curable

Hep C: CURABLE

Question 4

What is the tropism for viral hepatitis? At what point do you start treating someone who has recently got infected by Hep B or Hep C?

Answer 4

Liver hepatocytes
When the infection becomes chronic
Immune system, in some people, is able to clear Hep B + Hep C infections by itself

Question 5

What is the treatment for Hep B? What type of drug is this?

Answer 5

Tenofovir
Nucleotide analogue- Reverse transcriptase inhibitor
Inhibits disease progression

Question 6

What are the treatment options for Hep C? State the drug types.

Answer 6

Ribavirin (+ pegylated interferon): nucleoside analogue (purine analogue)
Boceprivir: protease inhibitor (for Hep C genotype 1)

Question 7

Describe the receptor interaction involved in HIV attachment and entry.

Answer 7

HIV GP120 binds to CD4 + CCR5 or CXCR4

HIV GP41 penetrates host cell membrane + the viral capsid enters

Question 8

State two drugs that interfere with HIV attachment and entry and state their targets.

Answer 8

Maraviroc: blocks CCR5 chemokine receptor
Enfuvirtide: binds to HIV GP41

Question 9

Name a nucleoside reverse transcriptase inhibitor used in HIV. How are they activated?

Answer 9

Zidovudine

3 step phosphorylation

Question 10

Name a nucleotide reverse transcriptase inhibitor used in HIV.

Answer 10

Tenofovir

Question 11

How do non-nucleoside reverse transcriptase inhibitors act in HIV? Give an example of an NNRTI.

Answer 11

Bind to the RT + cause a change in shape of the enzyme so it blocks HIV replication
E.g. Efavirenz

Question 12

Give an example of an integrase inhibitor used in HIV. What does this block

Answer 12

Raltegravir

Blocks viral integrase from inserting viral DNA into host DNA

Question 13

What viral gene encodes all the viral structural proteins in HIV?

Answer 13

Gag gene

Question 14

What must happen to the Gag precursor protein, in order to produce fully functioning virus particles?

Answer 14

Cleavage by a protease into the constituent proteins so that it can make the fully formed virus

Question 15

Name a drug used in HIV that acts a protease inhibitor and state one problem with its pharmacokinetics

Answer 15

Saquinavir

Low bioavailability

Question 16

What drug can be given to boost the level of the protease inhibitor in the circulation in HIV?

Answer 16

Ritonavir
Decreases metabolism of saquinavir
Co-administered as a “booster”

Question 17

What is the herpes virus surrounded by?

Answer 17

Tegument + a lipid bilayer

Question 18

What do the two different types of herpes cause?

Answer 18

HSV1: cold sores
HSV2: genital herpes

Question 19

What is the treatment for HSV?

Answer 19

Acyclovir

Nucleoside analogue specific because its activation requires viral kinases

Question 20

What envelope protein of influenza is important for the release of the virus into the host cell?

Answer 20

Neuraminidase

Question 21

Name an inhibitor of Neuraminidase protein

Answer 21

Oseltamivir

Question 22

Describe the process of HIV replication

Answer 22

Viral ssRNA is transcribed to dsDNA by reverse transcriptase

Question 23

When are HIV replication inhibitors effective?

Answer 23

When all 3 drugs (Zidovudine, Tenofovir + Efavirenz) are used in combination