L16 and L17 Immunology and pathogenesis of viral infections

Question 1

Antiviral cytokines are important in innate immunity. What are they?

Answer 1

Type I interferons (alpha and beta)

Question 2

Antiviral cytokines are secreted by dendritic cells and infected macrophages for? (2)

Answer 2

1. Antiviral effect: block viral replication, induce an antiviral state in infected and neighboring non-infected cells
2. Immunomodulation: increase in HLA expression, modulate B and T cells activities, increase NK and cytotoxic T cells

Question 3

Which of the following about innate immunity is correct?
A. Antiviral cytokines cause non-specific symptoms in viral infections, but not in immunocompromised patients in the elderly
B. Inflammatory cytokines are secreted
C. Complement system is activated
D. Acute phase proteins are present, but are more important in bacterial infections than viral
E. NK cells, Plasmacytoid dendritic cells and monocytes are important

Answer 3

All of the above
A: correct: non-specific e.g. fever, malaise, fatigue

E: plasmacytoid dendritic cells: viral sensors
Monocyes: become macrophage, produces type I IFN + dendritic cells

Question 4

IL-1, IL-6, TNF are _____________ in innate immunity.

Answer 4

inflammatory cytokines

Question 5

2 responses are important in adaptive immunity.

Briefly describe.

Answer 5

1. Cellular response: regulatory T cells (Th: Tsuppressor in 2:1), cytotoxic T cells
2. Humoral response: ADCC (antibody-dependent cellular cytotoxicity), opsonisation (enhanced phagocytosis), neutralization

Question 6

Which of the following about acute viral infection are correct?
A. Examples include Herpesvirus family
B. Short incubation time
C. Complete clearance 
D. Memory immunity after recovery
E. Prophylactic vaccination is useful

Answer 6

All except A

e.g. Influenza, hepatitis A, rubella

E***

Question 7

Which of the following about latent viral infection are correct?

A. Possess immune escape strategies
B. Reactivat upon immunosuppression or stimulation
C. Prophylactic vaccination is useful
D. Herpesvirus family is an example

Answer 7

Except C

Prophylactic vaccination less likely to be useful

Question 8

Which of the following about chronic viral infection are correct?
A. Examples include HBV, HCV, HIV
B. Possess immune escape strategies
C. Patients are asymptomatic at the beginning
D. It is infectious

Answer 8

All of the above

Question 9

What does it mean by persistent infection?

Answer 9

Latent infection + Chronic infection

Question 10

Tropism is the capacity of virus to infect specific cells.
e.g. HBV/HCV are herpatotropic

• HSV?
• HIV?

Answer 10

HSV: neurotropic
HIV: lymphotropic

Question 11

Which of the following are cytopathic effects?
A. cell death and release of virions by non-enveloped virus
B. budding by enveloped virus
C. multinucleated giant cells formed by cell fusion in RSV (respiratory syncytial virus)

Answer 11

All of the above

Question 12

Inclusion bodies are aggregates of mature virions/ viral proteins. List some virus that may form these.

Answer 12

1. Rabies
2. HSV
3. CMV

Question 13

Give an example of immune-mediated damage.

Answer 13

Damage of hepatocytes by HBV-specific T cells

Question 14

Guillain Barre syndrome following influenza vaccination and post-infectious encephalitis following influenza are examples of ________________ by molecular mimicry.

Answer 14

autoimmunity-mediated damage

Question 15

Virus infection can cause immunosuppresion in patients. Give 2 examples.

Answer 15

1. HIV: reduced CD4 T cells

2. Measles: paradoxically induce immunosuppresion for weaks > predispose to secondary bacterial infections