Week 3 - Viruses, Infection and Cancer

Question 1

What are the 3 chronic infectious causes of Cancer?

Answer 1

Viruses, Bacteria and Trematodes

Question 2

Name 8 viruses that cause cancer.

Answer 2

EBV
HBV
HCV
HHV-8
HIV-1
HPV
HTLV-1
MC Polyoma Virus

Question 3

What cancer does EBV cause, what type of cells does it affect and describe its DNA/RNA structure.

Answer 3

Lymphoma

B-cells and epithelial cells

dsDNA genome, 120-180nm, enveloped

Question 4

What cancer does HBV cause, what type of cells does it affect and describe its DNA/RNA structure.

Answer 4

Hepatocellular Carcinoma

Hepatocytes

Unique DNA genome (RT), 30-42nm in diameter, enveloped

Question 5

What cancer does HCV cause, what type of cells does it affect and describe its DNA/RNA structure.

Answer 5

Hepatocellular Carcinoma/Lymphoma

Hepatocytes and PBMC (Peripheral Blood Mononuclear cells)

Positive sense SS RNA genome, enveloped, 55-65nm

Question 6

What cancer does HHV-8 cause, what type of cells does it affect and describe its DNA/RNA structure.

Answer 6

Kaposi’s Sarcoma

PBMC

dsDNA genome, enveloped, 120nm

Question 7

What cancer does HIV-1 cause, what type of cells does it affect and describe its DNA/RNA structure.

Answer 7

Kaposi’s Sarcoma

CD4+ T-cells

Positive sense ss RNA (RT), enveloped, 120nm

Question 8

What cancer does HPV cause, what type of cells does it affect and describe its DNA/RNA structure.

Answer 8

Cervical Cancer

Basal cells from stratified epithelium

dsDNA genome, non-enveloped, 55nm.

Question 9

What cancer does HTLV-1 cause, what type of cells does it affect and describe its DNA/RNA structure.

Answer 9

Adult T-Cell Lymphoma

CD4+ T-cells

Positive sense ss RNA (RT), enveloped, 100nm

Question 10

What cancer does MC Polyoma Virus cause, what type of cells does it affect and describe its DNA/RNA structure.

Answer 10

Merkel Cell Carcinoma

No clear cell tropism

dsDNA non-enveloped, 45-55nm

Question 11

What is Kaposi’s Sarcoma?

Answer 11

Cancer affecting the lymph nodes and the skin – especially found in immuno-compromised individuals

Question 12

What is HBsAg?

What it is a differential for?

Answer 12

HBV antigen

Hepatitis B

Question 13

What is meant by the Cirrhotic Stage?

Answer 13

Cirrhosis is an abnormal liver condition in which there is irreversible scarring of the liver.

Question 14

Which one out of HBV and HCV has a readily available and succesful vaccine?

Answer 14

HBV

Question 15

What is the difference in type of genome in HBV compared to HCV?

Answer 15

HBV - DNA Virus

HCV - RNA Virus

Question 16

Lamivudine is an example of a drug used to treat HBV, what does it do?

Answer 16

Lamivudine is a reverse transcriptase inhibitor.

Question 17

Why is Lamivudine effective for HBV?

Answer 17

HBV’s genomic structure is that of 2 retroviruses packaged together with a RT gene.

Question 18

What type of Lymphoma is HCV strongly associated with?

Answer 18

B-cell Non Hodgkins lymphoma (NHL)

Significant but lesser association with other benign and malignant B-cell neoplasia’s, including multiple myeloma and CLL (leukaemia)

Question 19

What characteristic does HCV share with HIV-1 that makes it particularly elusive to the immune system?

Answer 19

Rapid resistance to Neutralising Antibodies (Nabs)

Protective vaccine based on Nabs very unlikely

May be susceptible to a non-neutralising therapeutic vaccine, a concept currently being explored for HIV

Question 20

What is an interferon?

Answer 20

Interferons (IFNs) are a group of signaling proteins made and released by host cells in response to the presence of several pathogens, such as viruses, bacteria, parasites, and also tumor cells.

In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses.

Question 21

What do drugs ending with the suffix -previr target?

Answer 21

Hep C protease inhibitor

Question 22

What do drugs ending with the suffix -navir target?

Answer 22

HIV-1 protease inhibitor

Question 23

How does Ribavirin work?

Answer 23

Nucleoside inhibitor - analog of guanosine, causes a capping of the sequence

Interference with mRNA replication

Question 24

What drug combination gives a 95% infection cure rate for HCV?

Answer 24

Sofosbuvir + Simeprevir, Peginterferon-Alpha and Ribavirin.

Question 25

What are the 3 groups of Herpes Virus and give an example of a virus in each group?

Answer 25

Alpha - HSV-1 (Cold Sores)
Beta - CMV
Gamma - EBV or HHV-8

Question 26

Other than cancer what condition does EBV cause?

Answer 26

Infectious Mononucleosis

Question 27

What does EBV do to B-cells?

Answer 27

Immortalise them

Converts them into a chronic activated state more like lymphoblastoid cells and may stabilise in intermediate activated states

Question 28

What is EBNA-1 and what is its role?

Answer 28

Epstein-Barr Nuclear Antigen 1

This sequence also seems to stabilize the protein, preventing proteasomal breakdown, as well as impairing antigen processing and MHC class I-restricted antigen presentation. This thereby inhibits the CD8-restricted cytotoxic T cell response against virus-infected cells.

Question 29

What is EBNA-1 and what is its role?

Answer 29

Epstein-Barr Nuclear Antigen 2

It contributes to the immortalisation of EBV infected cells.