Analysis of growth kinetics and viability in T cells treated with S. fusiforme. 1G5 T cells were treated with 2 mg/ml or 4 mg/ml S. fusiforme, or with 10-6 M ddC, or were mock treated. (A) Total cell number, and (B) % viable cells from total, was monitored at the indicated time points after infection, by trypan blue exclusion assay by counting at least 200 cells each in three different fields under ×20 magnification using an Olympus BH-2 fluorescence microscope. Experiment was repeated with primary human PBMC's treated with 1.5, 3, or 4.5 mg/ml S. fusiforme, or with 10-6 M ddC, or mock treated, and measured (C) Total cell number, and (D) % viable cells from total. PBMC's experiments are representative of 3 separate experiments, with SEM less than 5% (not shown).