Figure 6.

Quantification of interleukin-2 (IL-2) release by primary human T cells. T cells were loaded with citrate-coated superparamagnetic iron oxide nanoparticles (SPION^Citrate) at an iron concentration of 75 µg/mL for 24 h. After purification, they were stimulated with CD3/CD28/CD2 activator mix. The addition of recombinant human IL-2 was omitted. 0, 24, 72 and 120 h after stimulation, supernatants were collected and the amount of secreted IL-2 was measured by sandwich enzyme-linked immunosorbent assay (ELISA). The experiment was performed with three different donors. The mean values with standard deviations of each of the donors are shown as circles, their overall mean value as a red line. Significance between the overall mean values of loaded cells and control at the respective points of time is indicated by asterisks: ** p < 0.005. Abbreviations: ELISA: enzyme-linked immunosorbent assay, IL-2: interleukin-2, SPION^Citrate: citrate-coated superparamagnetic iron oxide nanoparticles.