Exposure to Mercury Alters Early Activation Events in Fish Leukocytes

• Published in: Environmental health perspectives Vol. 104; no. 10; pp. 1102 - 1106
• Main Authors: MacDougal, Kent C., Johnson, Matthew D., Burnett, Karen G.
• Format: Journal Article
• Language: English
• Published: United States National Institute of Environmental Health Sciences. National Institutes of Health. Department of Health, Education and Welfare 01.10.1996
• Subjects: Animals; B lymphocytes; Calcium; Calcium - metabolism; Cell growth; Cell lines; Cells, Cultured; Cultured cells; Dosage; Dose-Response Relationship, Drug; Fishes - immunology; Humans; Leukocytes; Leukocytes - drug effects; Leukocytes - immunology; Lymphocyte Activation - drug effects; Mercuric Chloride - toxicity; Mitogens; Phosphorylation; T lymphocytes; Tyrosine - metabolism
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.961041102

Although fish in natural populations may carry high body burdens of both organic and inorganic mercury, the effects of this divalent metal on such lower vertebrates is poorly understood. In this report, inorganic mercury in the form of mercuric chloride ( HgCl2) is shown to produce both high-dose inhibition and low-dose activation of leukocytes in a marine teleost fish, Sciaenops ocellatus. Concentrations of inorganic mercury ≥10 μM suppressed DNA synthesis and induced rapid influx of radiolabeled calcium, as well as tyrosine phosphorylation of numerous cellular proteins. Lower concentrations (0.1-1 μM) of HgCl2 that activated cell growth also induced a slow sustained rise in intracellular calcium in cells loaded with the calcium indicator dye fura-2, but did not produce detectable tyrosine phosphorylation of leukocyte proteins. These studies support the possibility that subtoxic doses of HgCl2 may inappropriately activate teleost leukocytes, potentially altering the processes that regulate the magnitude and specificity of the fish immune response to environmental pathogens.