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MACROPHAGE AGGREGATES AS BIOMARKERS OF EXPOSURE: FROM FERAL POPULATIONS TO LABORATORY MODELS
Citation:
Blazer, V. S., J W. Fournie, C. J. Schmitt, AND B. Wright. MACROPHAGE AGGREGATES AS BIOMARKERS OF EXPOSURE: FROM FERAL POPULATIONS TO LABORATORY MODELS. Presented at Aquatic Toxicity Workshop, Edmonton, Alberta, 3-6 October 1999.
Description:
Macrophage aggregates (MAs) are structures within the spleen, kidney and sometimes liver of teleost fishes. They are believed to function much like primitive lymph nodes in that phagocytized material is transported to these areas by macrophages, for destruction, recycling or storage. Initiation of the specific immune response may take place as the macrophages migrate to these structures. For many years researchers have noted increased number, size and/or pigment content of MAs in fish collected from contaminated versus reference sites. Hence, they have been used as a biomarker in the U.S. EPA's EMAP (Environmental Monitoring and Assessment Program) and as well as USGS's BEST (Biomonitoring of Environmental Status and Trends) program. Results from the EMAP-Estuaries program in the Gulf of Mexico have suggested that increased MAs are one of the best bioindicators of sediment contamination in bottom-dwelling fishes. Laboratory exposures to individual contaminants have begun for validation of this biomarker as well as to increase our understanding of the mechanisms of response and how it relates to immune status. Results from exposures to arsenic and dieldrin will be presented. In addition, confounding issues such as age and infectious disease will be discussed.