LEUKOPROLIFERATIVE RESPONSE OF SPLENOCYTES FROM ENGLISH SOLE (PLEURONECTES VETULUS) EXPOSED TO CHEMICAL CONTAMINANTS

The leukoproliferative (LP) response of splenic leukocytes from the ma rine benthic fish English sole (Pleuronectes vetulus) stimulated with the mitogens lipopolysaccharide (LPS), concanavalin A (Con A), and pok eweed mitogen (PWM) was examined as a biomarker of immunotoxic effects . English sole were exposed to contaminants, either by injection of an organic-solvent extract of a sediment containing polycyclic aromatic compounds (PACs) or placed for up to 5 weeks on a reference sediment c ontaining 0.15 to 1.5% (v/v) of the PAC-contaminated sediment. English sole either injected with the contaminated extract or held on PAC-con taminated sediment had an augmented response to Con A. The LP response to LPS showed no relationship to PAC exposure in laboratory-exposed e xposed fish, while PWM showed no consistent relationship to exposure t o PACs. In a field study, English sole captured from an urban area in Puget Sound, Washington, USA, contaminated with PACs and other chemica l contaminants had a significantly augmented LP response to Con A and PWM in comparison to the LP response in fish from a nonurban reference site. Fish from another nonurban site also had an augmented LP respon se to Con A, indicating that the elevation of the Con A LP response ca n also result from factors other than chemical contaminant exposure. I n addition, English sole from this site also had an augmented LP respo nse to LPS, whereas fish from urban sites did not exhibit an augmented LP response to LPS. Overall, the results demonstrated that although t he LP response in splenic leukocytes of English sole to Con A was link ed to contaminant exposure, the LP response to Con A did not exhibit h igh specificity as an indicator of chemical contaminant exposure. Howe ver, the concerted use of Con A, LPS, and PWM allowed fdr identificati on of apparent chemical contaminant-induced alterations of the LP resp onse in English sole from an urban area of Puget Sound.