Interaction of iron polymers with blood mononuclear cells and its detection with the Prussian Blue reaction

An inhibitory effect of iron salts on various immune functions in vitro has been reported in several laboratories during the last few years. This study confirms and extends those observations by showing that iron citrate inhibits the mitogen-induced (PHA, Con A and PWM) lymphocyte proliferation. Such inhibition is observed in the presence of ferric citrate with a metal-to-ligand molar ratio of 1:1 but not with ferric citrate with metal-to-ligand molar ratio 1:20 in which the formation of polynuclear iron complexes is prevented. Increasing the concentration of serum in the culture medium diminished the inhibitory effect of 1:1 ferric citrate. Using the Prussian Blue reaction the presence of ferric iron was observed on the cell surface. It is proposed that the deposition of polynuclear iron complexes on the lymphocytes membrane is one of the possible factors determining the iron inhibitory effect.