Hepatitis B+D

Question 1

Is the scale of difference for HepB, bigger or smaller than for HepC?

Answer 1

Much smaller

Question 2

What type of genome does HepB have?

Answer 2

DNA, enveloped virus

Question 3

What are the sub virus particles of HepB used as?

Answer 3

As a decoy system, they dont have a capsid etc., like the actual virus

Question 4

How many open reading frames are there?

Answer 4

4

Question 5

What length is pre-genomic RNA vs the genome length?

Answer 5

Pre genomic RNA is 3.5kb long
Genome is only 3.2kb long

Question 6

Where does pregenomic RNA start transcription?

Answer 6

DR1 region

Question 7

Surface antigen mRNA start transcription?

Answer 7

PreS1 region

Question 8

What does HBV bind to for entry?

Answer 8

Two receptors (NCTP - bile acid transporter, EGFR)

Question 9

What is the translocation process of HBV replication?

Answer 9

Internalises through an endosome, internalises into a vesicle, fuses when pH changes

Question 10

What is the conversion of rcDNA to cccDNA process with HBV?

Answer 10

Releases capsid protein containing partially dsDNA genome
Goes to nuclear membrnae, through pore, degrades capsid
Releases DNA into nucleus, gets converted into ccc DNA (covalently closed circular DNA)

Question 11

What happens to HepB following CCC DNA conversion?

Answer 11

MRNAs encoding different genes are made and they go to cytoplasm and interact with ribosomes to produce viral proteins

Question 12

Why is the surface antigen different to most other viral proteins in the processing?

Answer 12

Surface antigen is processed separately

Question 13

What are the two consequences following viral prtoein production?

Answer 13

Firstly sub virus particles are made using different secretion pathway to assembly of a virus particle
Independent expression system means that the virus can evolve to regualte to increase expression of those SVPs to control expression through multi vesicular body

Question 14

What is the final part of the HepB life cycle converting back to DNA +?

Answer 14

RNAse, pre-genomic RNA expressed from nucleus into cytoplasm
This gets reverse transcribed inside the capsid back into a copy of DNa which is identical to the one which has come in

Question 15

What does HBeAg do?

Answer 15

Expressed with active, high levels of replication, suppresses JAK/STAT signalling to reduce effectiveness of interferon signalling

Question 16

How many forms does core antigen have?

Answer 16

Two - one is called core antigen , one is E antigen

Question 17

How does open reading frame lead to core protein?

Answer 17

Open reading frame, has core protein and start codon. Encodes piece of mRNA to make E antigen, whole mRNA is E antigen that makes the protein. Then it is cleaved to make core, so get initiation and some E antigens get cleaved into core protein. It dimerises and changes conformation and allows it to be packaged into new particle

Question 18

How do pre-core mutations occur?

Answer 18

E antigen is highly immunogenic, applies large selection pressure for mutations. Mutated mRNA that is produced has a mutation, this stops E antigen being expressed. These are pre core mutants

Question 19

What is acute hepatitis?

Answer 19

Three phases of illness:
- prodrome malaise: fatigue, fever, vomiting etc.
- icteric phase: dark urine, yellow eyes, light coloured stools
Convalescence gradual recovery is normal

Question 20

Why are anti-HBs seen so much later after clearing the virus?

Answer 20

When you remove SPVs, they are soaking up antibodies, so now they dont mop up anymore antibodies now they have gone so only see surface antigen antibodies once the virus is gonna

Question 21

What happens in acute liver failure?

Answer 21

Symptoms similar to those of acute hepatitis to begin with
But more severe liver damage, bleeding tendency, small liver, brain oedema, altered behaviour and consciousness

Question 22

What are markers of liver damage?

Answer 22

AST and ALT

Question 23

What percent of people that have chronic HepB result in hepatocellular carcinoma?

Answer 23

1-5%

Question 24

What phases of chronic hepatitis B need antiviral drug treatment?

Answer 24

Immune active phase, cirrhosis in any phase, reactivation phase

Question 25

When do you have lifelong treatment for HepB?

Answer 25

Cirrhosis or APRI >2.0

Question 26

What is current treatment for HDV?

Answer 26

Is interferon alpha and bulevirtide