Lecture 10 2/13/24

Question 1

Why do very few antiviral drugs exist?

Answer 1

-compounds interfering with virus growth can adversely affect the host cell
-some medically important viruses cannot be propagated, have no animal model, and are dangerous (ease of handling)
-need to completely block virus replication, not just partially (otherwise leads to resistance)
-acute infections are short in duration

Question 2

Why is drug resistance common in viruses?

Answer 2

-viruses replicate efficiently
-modest to high mutation frequencies

Question 3

What are the dangers of drug resistance?

Answer 3

-patient cannot be treated with same drug
-infection can be unstoppable if other drugs do not exist

Question 4

What is the main mechanism of drug resistance in RNA viruses?

Answer 4

error prone RNA polymerase, which typically has no correction mechanism

Question 5

Which RNA viruses do encode for a proofreading exonuclease?

Answer 5

nidoviruses

Question 6

Why do DNA viruses evolve more slowly and with less diversity compared to RNA viruses?

Answer 6

DNA polymerases can excise and replace misincorporated nucleotides

Question 7

What are the characteristics of monoclonal antibodies?

Answer 7

-uses immunoglobulins from previously infected individuals as a drug
-provide temporary protection against a virus

Question 8

What are entry inhibitors?

Answer 8

drugs that prevent viruses from entering and infecting host cells

Question 9

What are the characteristics of Symmetrel/Amantadine?

Answer 9

-interacts with influenza viral M2 protein
-blocks entry of protons into virion, preventing uncoating

Question 10

What are the characteristics of Maraviroc CCR5 inhibitor?

Answer 10

-blocks CCR5 receptor
-prevents HIV/AIDS virus from entering and infecting host cells

Question 11

What are polymerase inhibitors?

Answer 11

drugs that target the viral replication process by inhibiting viral polymerase activity

Question 12

What are nucleoside inhibitors?

Answer 12

a type of polymerase inhibitor that gets incorporated into the viral genome, causing premature termination of the replication process

Question 13

What are non-nucleoside inhibitors?

Answer 13

a type of polymerase inhibitor that binds to the viral polymerase and inhibits its activity

Question 14

Which type of polymerase inhibitor is Acyclovir?

Answer 14

nucleoside inhibitor

Question 15

What is important about the ester derivative version of Acyclovir?

Answer 15

-releases Acyclovir when the ester is cleaved by cellular enzymes
-markedly improved bioavailability

Question 16

What are the characteristics of Remdesivir?

Answer 16

-inhibits replication of RNA viruses through mutagenesis
-must be delivered intravenously

Question 17

What are the characteristics of integrase inhibitors?

Answer 17

-treat HIV/AIDS
-prevent viral integrase enzyme from inserting viral DNA into host genome

Question 18

What are the characteristics of endonuclease inhibitors?

Answer 18

-inhibit influenza endonuclease
-prevents the endonuclease activity required for transcription and replication

Question 19

What are the characteristics of protease inhibitors?

Answer 19

-block protease enzymes from processing the viral proteins
-interfere with viral replication and maturation

Question 20

What are the characteristics of neuraminidase inhibitors?

Answer 20

-target influenza
-prevent release of new viruses from the cell
-mimic the natural sialic acid ligand

Question 21

What are the characteristics of RdRp nucleoside analog?

Answer 21

-broad spectrum
-believed to cause mutations in virus genome
-decreases ability of virus to replicate

Question 22

Why is combination therapy important?

Answer 22

-drugs suppress replication
-using multiple drugs at once allows for suppression of viruses that otherwise would have developed mutations to one of the drugs