Neuramide inhibits Epstein-Barr virus-induced transformation activity and proliferation of transformed B lymphocytes

Neuramide, in Italy, is a prescription drug and contains various polypeptides, with molecular weights ranging between 10 000 and 1000. It is commonly used in Italy for the clinical therapy of varicella-zoster and other viral herpetic diseases. In the present study, we investigated its effect on the in vitro transformation activity and transformed status of the Epstein-Barr virus (EBV), an herpesvirus closely associated with infectious mononucleosis (IM), nasopharyngeal carcinoma (NPC) and Burkitt's lymphoma (BL). Antiviral effects of neuramide were evaluated on viral-induced immortalization, transformed status and DNA synthesis. Our results show that simultaneous and/or post-treatment of EBV-infected lymphocytes with neuramide, at a concentration of 2 inhibiting units (IU)/ml, blocks EBV-mediated transformation and related events, whereas pretreatment does not show any inhibiting activity against EBV. Neuramide was also found to be a potent inhibitor of the proliferation of EBV-transformed B lymphocytes in vitro. These results suggest that the molecular mechanisms of action of the drug should be investigated more closely and also support the necessity to further purify the active polypeptides, in order to improve its possible in vivo efficacy in EBV-associated diseases, such as infectious mononucleosis and other lymphoproliferative diseases. (C) 1997 Elsevier Science B.V.