HIV and HepB Flashcards
What causes AIDS and what are the symptoms of this virus like?
HIV
symptoms are initially flu like but years later, can lead to AIDS
What are the 3 enzymes involved in HIV and what is their role?
Integrase: to incorporate the viruses dsDNA material with the hosts
Protease: the cleave the viral proteins once they have integrated into host cell in order for them to become smaller and form new virions
Reverse transcriptase: for RNA –> cDNA so that the cDNA can get inside the nucleus of the host cell
Why does HIV infect immune cells?
because the proteins on the viral protein bind to T helper cell receptors (these receptors are only on CD4 cells and macrophages)
How can we prevent/slow down viral replication?
- inhibit the 3 enzymes
How does HIV bind to host cell?
GP120 of the virus binds to CD4 receptor and co-receptor on host cell surface
In which order do the enzymes in HIV work to produce new virions?
- Reverse transcriptase
- Integrase
- Protease
What is the genetic difference between HIV and HepB?
HIV is RNA whereas HepB is DNA
How is HepB transmitted?
it’s a blood borne virus so healthcare professionals who take blood, are at risk
sexual contact, re-using needles, vertical transmission
What does partially dsDNA mean?
some of the DNA is double stranded and some is single stranded (in HepB)
What is the lifecycle of HepB?
cDNA is converted to cccDNA which is a template for transcription of RNAs
DNA core proteins released into cytoplasm for replication
transcripts become new virions which are released to make more copies.
mRNA is transported back to the cytoplasm
What are the symptoms of HepB?
jaundice, light stools, fatigue, GI symptoms
What organ does HepB affect?
the liver (hepatocytes) and so treatment is given to minimise liver damage
Give drugs used to treat HepB:
lamivudine, adefovir, tenofovir, telbivudine
What is an immune system modulator drug against HepB?
interferon alpha 2a
