Effect of N-acetylsphingosine on PEt and PA formation during EIgG-induced phagocytosis. PMNs were labeled with 1-O-[³H]octadecyl-sn-glycero-3-phosphocholine as previously described.18 Labeled cells (2 × 10⁶/mL) were incubated in the presence or absence of 10 μmol/L N-acetylsphingosine for 30 minutes at 22°C followed by activation with fMLP (100 nmol/L) for 10 minutes at 37°C. EIgG (10⁸/mL) were added to the activated PMN and phagocytosis allowed to proceed for 0.5 to 60 minutes at 37°C. At the indicated time points, PMNs were removed, EIgG not internalized removed by lysis, and lipids extracted and analyzed as described in Materials and Methods. Values represent the mean ± SD for three experiments. * = Significantly different from the zero time point (FMLP activation alone), P < .05.