FIG. 6.

Neutrophil apoptosis in response to GM-CSF, G-CSF, and conditioned medium from infected fibroblasts. Neutrophils were incubated with serial dilutions of GM-CSF (A), G-CSF (B), or conditioned medium from infected fibroblasts (C) for 18 h, and then apoptosis was determined using GFP-annexin and PI. Spontaneous apoptosis, seen using similar dilutions of conditioned medium from uninfected fibroblasts, or medium alone, is shown as a dotted line. The asterisk denotes the inflection point for each dose response (the maximal effect for the lowest dilution of the stimulus). Results are representative of two experiments for cytokines and six experiments for conditioned medium from infected fibroblasts.