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The T-cell–dependent antibody response is suppressed in mice exposed to 3.75, 7.5, 15, and 30 mg PFOA (perfluorooctanoic acid)/kg body weight (bw). Reduced bw accompanied immunosuppression at 15 and 30 mg/kg. We investigated the hypothesis that the observed immunosuppression is secondary to elevated serum corticosterone levels by assessing immune function in adrenalectomized (adx) or sham-operated C57BL/6N female mice exposed to 0, 7.5, or 15 mg PFOA/kg bw in drinking water for 10 days. Bw, primary antibody responses to a T-dependent antigen, clinical serum chemistries related to liver health, and serum corticosterone levels were evaluated. Exposure to 15 mg/kg decreased bw by approximately 10% after 8 days of dosing and until 2 days postdosing in both adx and sham animals; bw of adx animals were still reduced 5 days postdosing. IgM antibody titers were statistically reduced by 15% in sham animals and 18% in adx animals exposed to 15 mg/kg and by 11.8% in adx animals exposed to 7.5 mg/kg. Corticosterone concentrations were elevated by 157% in dosed sham animals relative to control animals and were reduced by 27% in dosed adx animals relative to control animals (neither changes were statistically significant). Clinical serum chemistries related to liver health were not statistically altered by either dose or adrenalectomy. The failure of adrenalectomy to protect mice from the immunosuppressive effects of PFOA indicates that suppression of antibody synthesis is not the result of liver toxicity or stress-related corticosterone production. [ABSTRACT FROM AUTHOR]

Natural killer (NK) cells are a subset of lymphocytes capable of killing tumor cells, virally infected cells and antibody-coated cells. Dibutyltin (DBT) dichloride is an organotin used as a stabilizer in polyvinylchloride (PVC) plastics and as a deworming product in poultry. DBT may leach from PVC water supply pipes and therefore poses a potential risk to human health. We previously reported diminished NK cells lysis of tumor cells following exposure to DBT in serum-free cell culture medium. However, under in vivo conditions, circulating cells will be exposed to DBT in the presence of 100% plasma; thus we investigated whether serum supplementation and incubation time modulates DBT effects on NK cell killing and the accumulation of DBT in freshly isolated NK cells, to determine whether a serum-free model accurately predicts possible effects of DBT on human NK cells under in vivo conditions. Lytic function was decreased by approximately 35% at an intracellular DBT (DBTi) concentration of 200μM and nearly complete loss of lytic function was observed at DBTi above 300μM for one h. However, an intracellular concentration of 50μM DBT, achieved over 24 h of exposure in 50% serum, reduced lytic function by 50%. Thus, conditions that reflect prolonged contact with circulating DBT, in the presence of serum, suggest that NK cell activity is decreased at lower DBTi. These data indicate that the model is useful in predicting potential human effects of relatively low DBTi concentrations. [ABSTRACT FROM AUTHOR]