The complexity of the Epstein-Barr virus infection in humans.

The Epstein-Barr virus (EBV) was isolated 40 years ago from cultures of Burkitt lymphoma cells (BL). The tumor was encountered in Africa and exhibited characteristical geographical, clinical and pathological features. Serological studies revealed that the virus is ubiquitous in humans. The primary infection is often accompanied by the syndrome of acute infectious mononucleosis (IM). It can induce malignant proliferation of B lymphocytes in conditions of immunodeficiency. EBV can immortalize B lymphocytes in culture. These cells carry the virus as episomes and express 9 virally encoded proteins. Their immunological recognition constitutes the surveillance which is responsible for the healthy virus carrier state. The main virus reservoir is represented by a low number of resting B lymphocyte which contain the viral genome but do not express its transformation proteins. The viral genome is detectable in all African BLs, in variable proportions of nasopharyngeal carcinoma, Hodgkin's disease, T cell lymphoma, lymphoepithelial like carcinoma, gastric carcinoma and leiomyosarcoma cases. The role of EBV in the genesis of these tumors is unknown.