Epstein-Barr virus: a human pathogen inducing lymphoproliferation in vivo and in vitro.

Epstein-Barr virus (EBV) is a pathogen that is associated with several diseases in humans. It causes most heterophile-positive cases of infectious mononucleosis. The virus is associated with another lymphoproliferative disease, African Burkitt's lymphoma, and with a malignancy of the nasopharynx, nasopharyngeal carcinoma. EBV appears to be a causative agent for some fatal lymphoproliferations in congenitally immunodeficient people. One proliferating cell type in infectious mononucleosis is an EBV-infected B lymphoblast. The tumor cell in African Burkitt's lymphoma is also an EBV-infected B lymphoblast. In vitro, EBV induces and maintains blast transformation of human B lymphocytes. All EBV-transformed cells, whether infected in vivo or in vitro, share many (but not all) virus-associated characteristics. Studies can now be performed in vitro that permit analysis of the various EBV-transformed cells and the host's immune responses to them.