Dose response of HIV-1 inhibition and cell viability in T cells treated with S. fusiforme. 1G5 T cells were treated for 24 h with increasing concentrations of S. fusiforme, or with 10-6 M ddC, as indicated; then infected with CXCR4 tropic HIV-1 (NL4-3) at multiplicity of infection (moi) of 0.01 for 1.5 h, washed 3 times, and returned to culture with same concentrations of each treatment for the duration of the experiment. (A) On day 3 after infection, intracellular luciferase gene marker expression was measured from cell lysates adjusted to same number of viable cells by MTT. Percent inhibition of HIV-1 was calculated utilizing formula in the Methods section, and plotted on the Y-axis as % Inhibition. In parallel, (B) cell viability for each treatment was quantified by MTT uptake, measured at 570 nm absorbance. Data are mean +/- SD of triplicates. Representative of three separate experiments.