Suppressive effect of iron on in vitro lymphocyte function: formation of iron polymers as a possible explanation

The evidence presented here indicates that ferric citrate inhibits both the phytohemagglutinin-induced lymphocyte proliferation and the formation of E rosettes by T lymphocytes. These inhibitory effects are only observed in the presence of ferric citrate with a metal to ligand molar ratio of (1:1) but not with ferric citrate (1:20) or sodium citrate. Since ferric citrate (1:1) at a physiological pH tends to hydrolyze and polymerize, we suggest that the inhibitory effect is mediated by the formation of iron polymers.