Epstein-Barr virus natural variation, cell growth control and cancer Event

Abstract: Most people in the world are persistently infected with Epstein-Barr virus (EBV) with no apparent disease. However, some primary EBV infections cause infectious mononucleosis and about 1.5% of all human cancers worldwide involve EBV, which is present in the tumour cells. Those cancers are mainly derived from B lymphocytes or epithelial cells infected by EBV.  The incidence of some of the cancers varies greatly in different parts of the world; for example, nasopharyngeal carcinoma incidence is 50 times higher in some parts of Southern China than in western countries and the malignant cells all contain EBV. Molecular investigation of EBV has focussed on a few lab strains but we have recently expanded the number of EBV viral genome sequences to over 200 (including many sequenced directly from the virus present in human saliva) and begun to investigate functional differences between strains. Major strain differences in the ability to promote growth of B lymphocytes can be mapped to specific amino acids in the EBV EBNA2 transcription factor. Variation in other viral genes relevant to EBV associated diseases (for example, the viral miRNAs which trans-regulate host cell mRNA) is also being investigated. Substantial variation in the gp350 EBV protein, which is the primary candidate for an EBV vaccine has been identified and this will be significant for efforts to make an EBV vaccine.