Immunotoxic biomarkers of anthropogenic impact in marine invertebrates.
Many chemicals enter the marine environment as a result of human activities where they
are available to exert a range of effects upon biota. Research has previously focused on the
effects of chemicals upon various biological functions of biota in situ. However the impact
of chemicals with immunotoxic functions has received little attention. The current research
focused on the immunotoxicity of environmental pollutants on marine invertebrates,
primarily Mytilus edulis. The aim of the research was to determine to what extent immune
function altered in M edulis following exposure to environmental contaminants and how
these alterations could be measured and incorporated into environmental monitoring
Exposure of M edulis to the immunotoxicants copper and tributyltin in the laboratory
indicated that biochemical measures of immune function were too sensitive for
experimental manipulations to be used as biomarkers of pollution-induced stress. However,
cellular analysis of immune function, as measured by an adapted immunotoxicity assay in
combination with a measure of cell viability, was responsive to pollution-induced stress in
a concentration-dependant manner. Cellular immune activity appeared to be regulated by
the cytokine IL-1 and involved the release of lytic factors from haemocyte populations.
Field evaluation of the immunotoxicity assay in New Bedford Harbour, USA, indicated
that environmental contaminants within the estuary had an immuntoxic effect upon in situ
mussel populations. The measure of immunotoxicity in mussel populations in New
Bedford Harbour was a more sensitive measure of environmental impact than routinely
used biomarkers such as lysosomal neutral red, cardiac monitoring and condition index.
The immunotoxicity assay is therefore proposed as a sensitive, low cost and reliable
biomarker of effect in mussel populations both in the laboratory and the field.