PARENT SESSION
70 - Metal Pollution: From Exposure to Ecological Effects
8:00 AM to 6:30 PM, Wednesday, 15 May 2002
Exhibition Area

(70-79) Immunotoxicity of mercury on american kestrel (Falco sparverius) lymphocytes in vitro.

Fournier, M.^*,1, Audet, M.¹, Smith, J.², Bird, D.³, Brousseau, P., ¹ INRS-Institut Armand-Frappier, Pointe-Claire, Québec, Canada² University of Saskatchewan, Saskaton, Saskatchewan, Canada³ Macdonald Campus of McGill University, Ste-Anne de Bellevue, Québec, Canada

ABSTRACT- The level of mercury increases in eastern North America and affects the bird species. The immune system of adult American kestrel were examined in vitro with the mitogenic assay and mercury to try to understand the effect of this heavy metal on wild bald eagle population in North America. The blood was collected from the jugular vein of kestrel. Peripheral blood lymphocytes (PBLs) were isolated and incubated in vitro for 88 hours to find the optimum concentrations of mitogen. PBLs were also incubated in vitro with 10^-9 to 10^-4 M of methylmercury and mercury chloride. The results showed a greatest response with final concentrations of 25 g/ml of concanavalin A (Con A), between 5-25 g/ml of phytohemagglutinin (PHA) and between 5-10 g/ml of pokeweed (PWM) mitogen. At 10^-6 M of methylmercury a significant decrease in PBLs transformation lymphoblastic comparatively of the control group was observed. At 10^-5 M of mercuric choride, we saw a significant decrease in PBLs transformation lymphoblastic comparatively of the control group. At higher dose (10^-5 and 10^-4 M), an important suppression (between 91% and 98%) could be attributed to cytoxicity and decreased cell viability. The IC50 for methylmercury is 3.6 x 10^-6 M and 8.1 x 10^-6 M for mercuric chloride. The organic form is more toxic than the inorganic form for the American kestrel. Finally, the reduced proliferation of kestrel cells exposed in vitro to mercury at concentration in the range of those observed in the feathers of Great Lakes bald eagle might provide a basis to support the hypothesis that contaminants induce immunosuppression in these animals.

Key words: Mercury, Immunotoxicology, Kestrel