Fig. 1. T.-gondii-infected 3T3 cells do not exhibit features characteristic of apoptosis. Uninfected and infected 3T3 fibroblasts were left untreated (No treatment) or stimulated to undergo apoptosis using 10 nM staurosporine (STS) or 10 ng ml^–1 TNF in the presence of cycloheximide (TNF/CX) for 8 hours. The cells were processed for electron microscopy. STS-treated uninfected cells (B) exhibit characteristic signs of apoptosis including chromatin condensation (arrowheads), vacuolation and the disorganization of cellular architecture. Following treatment with TNF/CX, uninfected wild-type fibroblasts exhibit extensive chromatin condensation and cellular disruption. By contrast, T.-gondii-infected cells (bottom) fail to exhibit the classic signs of apoptosis and display normal nuclear morphology and cytoplasmic organization (E,F). In the presented images, cellular debris is evident, presumably from an uninfected apoptotic cell(s). Scale bars, 2 µm.

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