Iron deficiency impairs protein synthesis in immune tissues of rat pups

To determine if decreased protein synthesis is a factor in reduced immunocompetence of iron deficiency, RNA, DNA and in vitro protein synthesis were measured. Rats were fed diets containing 6 (severe anemia), 11 (moderate anemia) or 250 (iron sufficient) mg iron/kg diet throughout gestation and lactation. On d 2 of lactation, litters were adjusted to contain six pups. On d 12 of lactation, two pups from each litter were immunized with sheep red blood cells (SRBC) and on d 17, tissues were removed for the determination of protein synthesis and evaluation of RNA and DNA contents. In the moderately iron-deficient pups, protein synthesis was lower (30%) in spleen than that in iron-sufficient pups. Protein synthesis in liver and thymus was not changed by moderate iron deficiency. In spleen, liver and thymus, protein synthesis in severely iron-deficient pups was less than half that of iron-sufficient pups. Protein synthesis in the spleen of the moderately iron-deficient group was higher after immunization with SRBC than in iron-sufficient controls, whereas the severely iron-deficient pups failed to respond. Impaired protein synthesis may be the mechanism responsible for compromised ability to produce antibody in iron deficiency.