Treating Viral Infections Flashcards
What are the four main stages of a viral life cycle?
Attachment/penetration
Uncoating/genome release
Translation
Repackaging
How do viruses cause cancer?
They modulate the host cell’s function and in this case increase the speed of the life cycle. This in turn reduces the cell’s ability to check for DNA mistakes which may result in cancer phenotypes
Generally speaking, what are the three mechanisms of antivirals?
Block steps in the viral life cycle
Stimulate the immune system to fight the virus
Target components of host cells
Describe how HIV affects immunity
It invades CD4+ T-cells and triggers apoptosis
It also stimulated the bystander effect which kills the surrounding T-cells too
Describe the HIV life cycle
The virus binds to CD4 receptors which triggers endocytosis. The endosome fuses with the virus envelope to release the genome. The RNA then undergoes reverse transcription and is integrated into the host cell DNA before the viral mRNA is translated and new virus particles are assembled.
Which stages of the HIV life cycle do antivirals affect?
Fusion/entry
Reverse transcription
Integration
Protein cleavage for final assembly
What effect does monotherapy have on HIV strains?
Monotherapy increases the likelihood that a particular strain will become resistant to a given drug, which means that all similar drugs will also be ineffective
What is HAART?
A combination of antivirals that inhibit every stage of the viral life cycle to prevent resistance
How can influenza be treated?
Supportive
Vaccination
Antiviral drugs
What proteins are present on influenza?
Matrix 2
Neuraminidase
Haemagglutinin
Describe the influenza life cycle
The virus binds to sialic acid and enters via endocytosis and the endosome and viral envelope fuse. The genome is replicated using the host’s enzymes and the virus reassembles on the membrane
What causes mutations in flu?
Antigenic drift and antigenic shift
How do DAS181 antivirals work?
Cleaves sialic acid to prevent influenza from binding to target cells
How do adamantanes work?
Blocks N2 channels in endosomes to prevent pH sensitivity and inhibits uncoating
How do neuraminidase inhibitors work?
Mimic the structure of sialic acid so neuraminidase cannot cleave sialic acid and haemagglutinin during viral reassembly
