ACTIVITIES OF THE 4 OPTICAL ISOMERS OF 2',3'-DIDEOXY-3'-THIACYTIDINE (BCH-189) AGAINST HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 IN HUMAN-LYMPHOCYTES

Four different isomers of 2',3'-dideoxy-3'-thiacytidine [beta-DL-(+/-)-BCH-189] were evaluated in primary human lymphocytes infected with human immunodeficiency virus type 1. The beta-L-(-) isomer was the most potent enantiomer, with a median effective concentration of 1.8 nM and no discernible cytotoxicity up to 100-mu-M. The relative order of potencies for the isomers was beta-L-(-) > beta-DL-(+/-) racemic > beta-D-(+) > alpha-L(+) > alpha-D-(-). The beta-L-(-) enantiomer was as potent as 3'-azido-3'-deoxythymidine.