Effects of Fumonisin B1on the Immune System of Sprague–Dawley Rats Following a 14-Day Oral (Gavage) Exposure

The effects of fumonisin B₁(FB₁) on the immune system of Sprague–Dawley rats were investigated. Groups of male and female rats (10 rats/group) were gavaged daily for 14 days with doses of 0, 5, 15, and 25 mg/kg body wt/day and the primary (IgM) response to sheep red blood cells expressed as plaque-forming cell numbers/10⁶spleen mononuclear leukocytes (PFC/10⁶splenocytes) and PFC/spleen was determined. There was a significant dose-related linear trend toward decreased PFC/10⁶splenocytes (p= 0.003) and PFC/spleen cells (p= 0.001) in the male rats. Body weights, expressed as a percentage of the control, were significantly reduced (p= 0.002) in the male rats administered 15 and 25 mg/kg doses. The PFC numbers in female rats were not affected significantly by treatment (p> 0.05). For the remaining immunotoxicity studies, groups of male rats (10 rats/group) were gavaged with FB₁doses of 0, 1, 5, and 15 mg/kg body wt/day for 14 days. There was a weakly significant dose-related trend toward increased numbers of serum immunoglobulin class G (p= 0.04). Also a significant dose-related increase (p= 0.013) inListeria monocytogenesnumbers was observed in the spleen at 24 hr postinfection. Treatment did not have a significant effect on organ weights, hematology, mitogen-induced lymphocyte transformation, calcium mobilization, the numbers of leukocytes and T-lymphocyte subsets, the natural killer cell activity, and phagocytosis (p≥ 0.05). These observations suggested that FB₁may have indirect consequences for human health and warrant further investigations.