Spleen natural killer cells from iron-deficient rat pups manifest an altered ability to be stimulated by interferon.

The effect of in vitro interferon stimulation on nonimmune- and immune-spleen natural killer cell activity was studied in iron-deficient rat pups. Dams were fed 6, 12 or 250 mg Fe/kg diet during gestation and lactation. Approximately one-half of the 17-d-old pups were injected intraperitoneally with 10(5) plaque-forming units of vaccinia virus. Four d later, nonimmune and vaccinia-immune pups were killed. Spleen lymphocyte suspensions were prepared and plated with or without rat alpha/beta interferon for 2 h at 37 degrees C. Washed lymphocytes were combined with 51chromium-labeled YAC-1 target cells and co-cultured for 4 and 16 h at 10 and 50:1 effector-to-target ratios. Hemoglobin concentration, hematocrit, body weight, spleen weight and lymphocyte numbers per spleen were lower in iron-deficient pups than in controls. In general, interferon stimulation increased natural killer cell activity above baseline. Analysis of variance comparison among groups showed that interferon was incapable of restoring natural killer cell activity of iron-deficient pups to the levels observed in control pups. Impaired spleen natural killer cell activity in iron-deficient neonates may be due to a limited capacity for stimulation by interferon.