Antivirals

Question 1

What surrounds the genetic material in viruses?

Answer 1

Capsid (protein shell surrounding the genetic material)

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

a. Hepatitis B 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

Question 3

Describe the relative curability of Hep B and Hep C.

Answer 3

Hep B – not curable Hep C – CURABLE

Question 4

At what point do you start treating someone who has recently got infected by Hep B or Hep C?

Answer 4

When the infection becomes chronic The immune system, in some people, is able to clear Hep B and Hep C infections by itself

Question 5

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

Answer 5

• Tenofovir
• Nucleotide reverse transcriptase inhibitor

Question 6

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

Answer 6

Ribavirin (+ Peginterferon alfa) Ribavirin is a nucleoside analogue that prevents viral RNA synthesis Boceprivir – protease inhibitor (most effective against Hep C genotype 1)

Question 7

Describe the receptor interaction involved in HIV attachment and entry.

Answer 7

HIV GP120 binds to CD4 GP120 also binds to either CCR5 or CXCR4 Then HIV GP41 penetrates the host cell membrane and the viral capsid enters

Question 8

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

Answer 8

• Enfuvirtide – GP41 transmembrane glycoprotein
• Maraviroc –CCR5 chemokine receptor

Question 9

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

Answer 9

Zidovudine Three step phosphorylation

Question 10

Name a nucleotide reverse transcriptase inhibitor. How are they activated?

Answer 10

Tenofovir Fewer than 3 phosphorylation steps

Question 11

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

Answer 11

They bind to the reverse transcriptase and cause a change in shape of the enzyme so it blocks HIV replication Example: Efavirenz

Question 12

Give an example of an integrase inhibitor.

Answer 12

Raltegravir

Question 13

What viral gene encodes all the viral structural proteins?

Answer 13

Gag gene

Question 14

What must happen to the precursor that encodes all viral structural proteins in order to produce fully functioning virus particles?

Answer 14

This must be cleaved by a protease into the constituent proteins so that it can make the fully formed virus

Question 15

Name a drug that acts a protease inhibitor and state one problem with its pharmacokinetics.

Answer 15

Saquinavir

Question 16

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

Answer 16

Ritonavir This decreases the metabolism of saquinavir

Question 17

What is the herpes virus surrounded by?

Answer 17

Tegument and a lipid bilayer

Question 18

What do the two different types of herpes cause?

Answer 18

HSV1 – cold sores HSV2 – genital herpes usually this way round, not always

Question 19

What is the treatment for HSV?

Answer 19

Acyclovir Nucleoside analogue that is 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 this influenza envelope protein

Answer 21

Oseltamivir

Question 22

What is the tropism of viral hepititis?

Answer 22

Liver hepatocytes

Question 23

What kind of people are immune to HIV?

Answer 23

Those with the genetic mutation delta 32 They dont have the CCR5 chemokine receptor so HIV is unable to enter their cells

Question 24

What’s the 1st step of a HIV replication inside a cell?

Answer 24

Viral single-stranded RNA -> double stranded DNA by reverse transcriptase

Question 25

What is the difference between the classes of drugs that target HIV replication?

Answer 25

Nucleoside RT inhibitors Activated by 3 step phosphorylation process (E.g. Zidovudine) Nucleotide RT inhibitors Fewer phosphorylation steps required (E.g. Tenofovir) Non-nucleoside RT inhibitors No phosphorylation required Not incorporated into viral DNA (E.g. Efavirenz)

Question 26

Why are HIV medications given in combination?

Answer 26

If one is jsut given on its own it doesn’t have a large enough effect to destroy the virus to the virus develops resistance to it.

Question 27

What are the targets for hepatitis treatment?

Answer 27

• Hep B: Reverse transcriptase
• Hep C: RNA synthesis (various mechanisms) Viral protease

Question 28

What are the targets for HIV treatment?

Answer 28

Attachment and Entry - HIV GP41 and cellular CCR5 Replication - HIV reverse transcriptase Viral DNA intergration - HIV integrase Assembly and release - HIV protease

Question 29

What is different about Non-nucleoside RT inhibitors compared to other RT inhibitors?

Answer 29

No phosphorylation required Not incorporated into viral DNA

Question 30

Why did oseltamivir turn out to be not very useful?

Answer 30

You need to take it immediately when you get the virsus (asymptomatic) There is a short incubation period whilst the virus infects its cells After this symptoms appear but by then its too late to take oseltamivir as too many cells are infected

Question 31

What is the tropism of HIV?

Answer 31

leukocytes