ABSTRACT
Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus that is carried by more than 95% of the human population as a lifelong latent infection [reviewed in (1) and Chapter 3]. EBV immortalizes, or transforms, B-cells in vitro. A combination of six viral nuclear gene products and two membrane-associated viral proteins in transformed B-cells is primarily responsible for the changes in cell growth and phenotype. Expression of the growth-transformed phenotype has only been detected in the B-cell follicles of tonsils (2), while in peripheral blood, EBV is detected in a very small number of resting memory B-cells. EBV gene expression in these cells is restricted to, at most, one or two viral genes that are probably invisible to the immune system. A normal immune response appears to be essential in maintaining the asymptomatic carrier-state, as demonstrated by the occurrence of posttransplant lymphoproliferative disease (PTLD) in immunocompromised persons.
