Fig. (4) Effects of DB-2 fractions. (a) Each fraction was evaluated for cytotoxicity using the MTT assay. Controls for DMSO concentration (solvent), as well as positive (cells alone) and negative (addition of 100% DMSO) controls were performed. The % of cellular survival was determined in each culture containing a fraction by comparison with the solvent control. (b) A3.01 cells were infected with HIV-1_LAV in the presence of the DB-2 fractions DD, DE, DF and DG to determine the effect on viral replication. DD, DF and DG were tested at 1 µg/mL, while DE was tested at 0.5 µg/mL. Controls for DMSO concentration present in extract wells (DMSO), positive inhibition of viral replication (10 µM and 20 µM AZT), and absence of extract (LAV) and virus (mock) were included. Virus levels in culture supernatant were determined by RT assay.