Figure 5.

ASM delivery efficiency and functional activity. (A) TNFα-stimulated NPD fibroblasts were incubated for 1 h at 37 °C with free ¹²⁵I-ASM or anti-ICAM/¹²⁵I-ASM NCs. The amount of cell-associated ASM was determined in a gamma counter from the cell lysates. (B) Additionally, ASM activity was measured with a sphingomyelinase kit (Molecular Probes) to detect the conversion of sphingomyelin into fluorescent Resorufin in cell lysates. Data is presented as a percentage of Wt ASM activity. (C) Intracellular enzyme activity after removing the surface-bound ASM fraction with an acid glycine solution. Data are a percentage of total ASM activity. (A–C) Data are the mean ± SEM. *Comparison with cells treated with free ASM (p < 0.05 by Student’s t test).