Figure 4.

Incorporation and release of ⁵⁵Fe by M1 and M2 macrophages. M1 and M2 macrophages were incubated overnight with [⁵⁵Fe] ferric iron citrate (2.5 μM iron) in the presence of ascorbic acid (A) and (B) or with 2.5 μM transferrin bound ⁵⁵Fe (C and D), or with [⁵⁵Fe] ferric iron citrate in the presence of ascorbic acid (150 μM iron, E), washed and lysed either immediately or after a 24 h chase. (A, C and E) Cell-associated radioactivity (cpm/mg of protein extract, y axis) was evaluated. Results represent the mean ± SD of quadruplicate samples. **P<0.01, significantly different from control. (B and D) Cell extracts were obtained at the times indicated and were resolved on a native polyacrylamide gel. Radioactive iron incorporation into Ft was evaluated by autoradiography.