IRON POLYMERS IMPAIR THE FUNCTION AND MATURATION OF MACROPHAGES

An inhibitory effect of iron salts on various immune functions in vitr o has been reported in several laboratories during the last years. Thi s work extends such observations by showing that iron citrate, but not sodium citrate, inhibits the function and maturation of murine macrop hages (MOs). However, such inhibition is only observed in the presence of ferric citrate with a metal-to-ligand molar ratio of 1:1, but not with ferric citrate with a metal-to-ligand molar ratio of 1:10 in whic h the hydrolyzation and polymerization of iron in physiological soluti ons is prevented. Accumulation of ferric iron on the cytoplasm of MOs was observed, but only in the group of MOs treated with ferric citrate 1:1. Increasing the concentration of serum in the culture medium dimi nished the inhibitory effect of ferric citrate 1:1. The inhibitory cap acity of iron polymer was probably associated to its ability to both i nteract with the cell constituents of the cytoplasm and stimulate lipi d peroxidation.