Figure 2. Kinetics of NTBI uptake in T lymphocytes and hepatocytes.

NTBI uptake by human T lymphocytes (A) and HepG2 cells (B). Cells were incubated with different concentrations of ⁵⁵Fe-citrate (1 µM, 5 µM, 10 µM, 100 µM, 200 µM and 500 µM) at 37°C and intracellular iron quantified at various time points (0, 15, 30, 60 and 120 min) (n = 3). The values obtained during the first 30 min of incubation, when the transport system is not saturated, were used to calculate the rate of uptake for each concentration. CD3⁺ cells reach saturation at 200 µM of Fe-citrate and present a maximum rate of 0.4 nmol/min/10⁶ cells, as opposite to HepG2 cells, which do not saturate even at 500 µM and present a faster rate of uptake (21 nmol/min/10⁶ cells).