EBV review

Question 1

EBV virion features

Answer 1

Gammaherpesvirus, large double stranded DNA genome, enveloped, labile in the environment
All herpes viruses, including EBV 2 life cycles (lytic replication/ latency)

Question 2

Herpesvirus lytic replication

Answer 2

1. binding and fusion
2. transport of DNA to the nucleus
3. Viral vhs degrades host mRNA
4. Viral transcription factor VP16 localizes to the nucelus to initiate viral gene transcription
5. Viral DNA circulizes
6. HSV alpha genes transcribed by host RNAP2
   7/8. Some alpha gene products transactivate transcription of beta genes, beta gene products are required for viral DNA syntesis
7. Viral DNA synthesis triggers expression of gamma viral gene
8. Many gamma products are structural components of the virion
9. Viral DNA is packaged into capsid
10. Filled viral capsid bud thru host membranes to form a mature virion that exits from the cell

Question 3

Latent EBV

Answer 3

Early alpha and some beta are produced
Only EBNA1 might be expressed
When plasma cells differentiate into plasma cells will cause EBV reactivation
alterations of the immune system (triggers) cause it to reactivte

Question 4

EBV infection in B cells

Answer 4

EBV encoded RNAS transcribed in all infected cells but never translated into a protein

Question 5

Infectious EBC is secreted in saliva all the time even in healthy idif=viduals

Answer 5

EBV acquired in the 1st decade of life leads to mild cold like symproms

EBV acquired in adolescence will become an acute infection and is termed infectious mononucleosis-95% of college kids are infected

Infections mono is characterized by a massive expansion of T cells, these T cells are CD8+, Downey cells, higly activated effector cells with many if not most of them being specific for EBV infected B cells

A significant increase in activated B cells leading to increase in production of AB against self Ag

Question 6

Clinical course of Infectious mononucleosis

Answer 6

Fever lymphadenopathy, malaise and fatigue, vrus in saliva, atypical lymphocytes, heterophile, Anti Ea, Anti VCA IgM, IgG, Anti EBNA

Question 7

Mechanisms of Viral oncogenesis

Answer 7

Direct transformation (80% or greater of cancer cells have to be virus positive)
Hit and run (Virus changes cellular environment, promotes mutagenesis)
Bystander effect (virus infected cells secrete a storm of growth factor