The influence of industrial intoxication with copper on selected parameters of cellular immunity in sheep

In the present study we investigated the dynamics of selected parameters of cellular immunity (metabolic activity of phagocytes, bactericidal activity of phagocytes and polyclonal activation of lymphocytes) in improved Vallachian sheep during natural chronic intoxication with copper emitted by a copper producing industrial plant. Sheep were reared for five years close to the industrial plant producing non-ferrous metals. Each of ten experimental sheep (groups A, B) received 2.5 g per day of the material emitted by the plant mentioned through an individual stomach tube to imitate natural intoxication after their transport to the clinic. In addition to that, sheep of the group B received in the same way 400 mg of ammonium molybdate and 800 mg of sodium sulphate until the 24th day of experiment for a therapeutic purpose. Three clinically healthy sheep of the same age represented a control group. The blood from all animals was sampled from v. jugularis before the experiment and on days 10, 17, 24, 31, 38 and 45. During the entire experiment, the metabolic activity of phagocytes, reflected in the values of index of metabolic activity, showed a significant decrease (p < 0.01) in both experimental groups in comparison with the control and an increase in the number of surviving bacteria which exceeded the physiological limit in the test of bactericidal activity of phagocytes. Similar to that, the values of migration index during polyclonal activation of lymphocytes with phytohaemagglutinine pointed to the decreased response of lymphocytes to the mitogenic stimulus in both experimental groups in comparison with the control (p < 0.01; p < 0.05, resp.). The therapeutical administration of ammonium molybdate and sodium sulphate to sheep of the group B had no effect on the parameters of cellular immunity investigated when compared with the group A. The values of selected parameters of cellular immunity in sheep which exhibited chronic cuprotoxicosis allowed us to state that the emissions from the copper producing plant caused an immunosuppressive effect in the sheep investigated, manifested by decreased values of metabolic and bactericidal activity of phagocytes as well as by the decreased response of lymphocytes to mitogenic activation.