[AntiEBV activity of 6-azacytidine and its derivatives].

Epstein-Barr virus (EBV) causes several lymphoproliferative diseases, lesions of the central and peripheral nervous systems. Spectrum of etiotropic medicines against EBV is limited. The paper presents the anti-virus research of modified nucleoside with a wide spectrum of action - 6-azacytidine and its derivatives (2'-3'-seco-5-methyl-6-AC, 2',3'-dideoxy-2',3'-didehydro-6-AC and 2'-deoxy-6-AC) on the model of Epstein-Barr virus in Raji lymphoblastoid cells. Parameters of cytotoxicity (CC,) for the investigated substances were determined which amounted to 120 microg/ml, 180 microg/ml, 500 microg/ml, 330 microg/ml, and the effective concentration (ECU)--0.5 microg/ml. 1 microg/ml, 4 microg/ml, 11 microg/ml, in accordance with the sequence of preparations listed above. The results indicate a high antiEBV activity since their selectivity indexes (SI) were 240, 180, 125, 30 that is 1.3-10 times higher than the reference substance acycloguanosine. Apoptosis-stimulating action of 6-azacytidine and its derivatives was revealed. An increase of percentage of apoptotic cells in EBV-infected Raji cells and those treated with investigated substances as compared to uninfected ones was observed after 24 hours. Thus, our results provide new biological properties of the azacytidine substances.