CHRONIC INTAKE OF A MARGINALLY LOW COPPER DIET IMPAIRS IN-VITRO ACTIVITIES OF LYMPHOCYTES AND NEUTROPHILS FROM MALE-RATS DESPITE MINIMAL IMPACT ON CONVENTIONAL INDICATORS OF COPPER STATUS

We investigated the impact of chronic intake of a diet marginally low in Cu on traditional indicators of Cu status and in vitro activities o f splenic mononuclear cells and neutrophils. Pregnant Sprague-Dawley r ats were fed diets containing either 2.8 (LCu) or 6.7 [adequate (ACu)] mg Cu/kg from midgestation through lactation. Weaned male and female o ffspring were fed the same diets as their dams until 6 months of age. Dietary Cu level did not alter growth, heart weight, the concentration s of Cu or the activities of cuproenzymes in serum and most tissues. I n contrast, splenic mononuclear cells (MNC) from males, but not female s, fed the LCu diet were less responsive to in vitro mitogenic activat ion and generated less interleukin-2 bioactivity than cultures prepare d from males fed the ACu diet. Repletion with the ACu diet for 2 wk re stored in vitro activities of splenic MNC to control levels. The phorb ol myristate acetate-induced generation of superoxide anion by elicite d neutrophils from male rodents fed the LCu diet was only 60% that of cells from the ACu diet group. Brain Cu in adult rats fed LCu diet was irreversibly- decreased compared with those fed ACu diet. These data show that the in vitro activities of T lymphocytes and neutrophils iso lated from adult male rats chronically fed a diet marginally low in Cu were significantly suppressed without marked alterations in the tradi tional indicators of Cu status.