Epstein Barr Virus - Skildum

Question 1

What are the “classic triad” symptoms of infectious mononucleosis?

Answer 1

• Pharyngitis
• Lymphadenopathy
• Fever

Question 2

What tests and procedures are used to determine whether the cause of infectious mononucleosis was Epstein Barr virus?

Answer 2

Monospot test

Question 3

What does the monospot test detect?

Answer 3

• Heterophile antibodies produced by polyclonal expansion of B-cells

Question 4

The presence of what in a patient’s blood indicates an acute infection?

Answer 4

VCA-IgM

(viral capsid antigen - monoclonal)

Question 5

The presence of what in a patient’s blood indicates a previous infection?

Answer 5

VCA-IgG

Question 6

The appearance of what in a blood smear is diagnostic for EBV?

Answer 6

Atypical lymphocytes

(Downey cells)

Question 7

What is the treatment for EBV?

Answer 7

• Infectious mononucleosis: SUPPORTIVE
  
  • inform patient of EBV related malignancies he/she may be at risk for later in life

Question 8

EBV:

Family?

Genomic organization?

Envelope status?

Capsid symmetry?

Answer 8

• Herpesviridae (HHV-4)
• dsDNA
• Enveloped
• Icosahedral

Question 9

What is the tropism of EBV?

Answer 9

• Acute: epithelial cells of oropharynx
  
  • supports lytic life cycle
• Latent: B-cells

Question 10

How does EBV gain entry into B-cells?

Answer 10

• viral envelope proteins bind the C3d complement receptor (CD21)
  
  • initiates endocytosis

Question 11

What does the EBV oncogen LMP-1 function as?

Answer 11

• constitutively active CD40
  
  • CD40 is normally responsible for CD4+ T-cell dependent activation of B-cells

Question 12

LMP-1 activates what transcription factor?

Answer 12

NF-_KB

(increases proliferative potential)

Question 13

What does the EBV oncogene LMP-2 function as?

Answer 13

• constitutively active B-cell receptor
  
  • without antigen present
  • B-cell receptor is normally responsible for antigent dependent B-cell activation.

Question 14

LMP-2 activates what transcription factors?

Answer 14

fos/jun

(support proliferation)

Question 15

What are the four consequences of the EBV oncogene EBNA3C binding to and activating cyclin D1 complexes?

Answer 15

1. Hyperphosphorylation of Rb tumor suppressor (inhibits it)
2. Activation of E2F family transcription factors
3. Expression of genes that control DNA replication
4. Cell cycle progression

Question 16

What malignancies are associated with EBV?

Answer 16

1. nasopharyngeal carcinoma
2. Burkitt lymphoma
3. Hodgkin disease
4. Non-hodgkin lymphoma
5. X-linked lymphoproliferative disease

Question 17

What is the molecular basis for X-linked lymphoproliferative disease?

Answer 17

• Mutation that results in a non-functional SAP protein.
  
  • involved in a “dampening pathway”
  • controls apoptotic cell death of activated T-cells
  • when absent the immune response has “no brakes”
    
    • T-cells do not stop proliferating

Question 18

What is the clinical presentation of X-linked lymphoproliferative disease?

Answer 18

• severe, rapid infectious mononucleosis
• median age = 3 years old
• X-linked recessive inheritance
• survival rate: 1-2 months
• patients who survive the infectious mononucleosis develop lymphoproliferative disorders and dysgammaglobulinemias