We study EBV's molecular functions to understand how the virus contributes to different types of disease. We analyse the immune system of virus carriers to find out how EBV and other herpes viruses are kept in check, and why immune control has failed in patients with disease. We also investigate the origins of cancers of the immune system - lymphoma and leukaemia. Our ultimate goal is to develop new drugs, vaccines and cell-based therapies in order to efficiently treat or – preferentially – prevent infectious diseases and cancer.