Epstein barr virus

1. EPSTEIN-BARR VIRUS
Structure
 Double stranded DNA virus
 Enveloped
 EBV has a toroid-shaped DNA core in
a nucleocapsid
 External glycoprotein spikes, and a
protein tegument between the
nucleocapsid and envelope

2. EPSTEIN-BARR VIRUS (EBV)
 EBV infects human B-lymphocytes and epithelial cells and long-term infection
stimulates them to proliferate and develop into malignancies of corresponding
cells. EBV is implicated in the following human tumours:
i. Burkitt lymphoma
ii. Anaplastic nasopharyngeal carcinoma
iii. Post-transplant lymphoproliferative disease
iv. Primary CNS lymphoma in AIDS patients
v. Hodgkin lymphoma

3. Mode of Transmission
 Oral secretion : Kissing
 Blood products
 Transplanted Organ

4. EBV-induced oncogenesis
B lymphocyte
(EBV-infected)
Cell proliferation
dysegulated
(CD40-like effect)
LMP1 expressed Activates BCL2
Growth signalling
Prevents apoptosis
Epithelial cell
(EBV-infected)
Elaborates EBNA-2
(via NF-kB, JAK/stat pathway)
Activates cyclin D and
SRC family
Stimulates B-cell
proliferation
Burkitt Lymphoma
Nasopharyngeal
carcinoma

5.  In immunocompetent individuals, LMP1 is kept under control by the body`s
immune system. Therefore, in these individuals lymphoma cells appear only after
another characterstic mutation t(8;14) activates growth promoting MYC oncogene.

7. Burkitt Lymphoma
 Burkitt lymphoma was initially noticed in African children by Burkitt in 1958 but is now
known to occur in 2 forms.
• African endemic form
• Sporadic form (seen else where in world)
 It usually occurs in children in between the age of 3-14 years.
 It responds favorably to chemotherapy.
 The association between Burkitt lymphoma and EBV is observed from the following
features.
• Over 90% of Burkitt lymphomas are EBV-positive in which the tumour cells carry the viral DNA.
• 100% cases of Burkitt lymphoma show elevated levels of antibody titres to various EBV
antigens.
• EBV has strong tropism for B lymphocytes. EBV-infected B cells grown in cultures are
immortalized, i.e. they continue to develop further along B-cell-line to propagate their
progeny in the altered form.

8. Anaplastic nasopharyngeal carcinoma
 This is the other tumour having involvement of EBV infection.
 The tumour is prevalent in South-East Asia, especially in the Chinese, and in
Eskimos.
 The evidence linking EBV infection with this tumour is as follows:
i. 100% cases of nasopharyngeal carcinoma carry DNA of EBV in nuclei of tumour cells.
ii. Individuals with this tumour have titres of antibodies to various EBV antigens.

9. Diagnosis
 Heterophile anti body test
 EBV- specific anti-bodies test
 Culture of EBV requires 4 to 6 weeks
 Real time PCR - expensive and not commonly used.

10. Prevention
 Avoid contact with saliva
 Do not kiss children on the mouth.
 Maintain clean conditions
 Vaccines : not available currently