In vitro immunomodulation by pentachlorophenol in phagocytes from an estuarine teleost, Fundulus heteroclitus, as measured by chemiluminescence activity.

Chemiluminescence (CL) was used to assay effects of pentachlorophenol (PCP) on the production of reactive oxygen intermediates (ROIs) generated by leukocytes from an estuarine teleost, Fundulus heteroclitus. Two parameters were measured during the phagocytically-induced respiratory burst: peak CL (maximal value) and total CL (temporal summation of induced values). Phagocytes obtained from the pronephros were incubated in the presence of sublethal doses of analytical (A-) or technical (T-) grades of PCP. Technical PCP has been reported to be more highly immunosuppressive than A-PCP in mammals; this effect was attributed to dioxins and other contaminants produced during manufacture. In this fish, both grades of the compound produced significant dose-dependent inhibition of peak and total CL. However, there were few significant differences between the effects of the two PCP grades on the magnitude of the CL responses at identical, sublethal concentrations, although T-PCP did produce a more marked reduction in the relative level of leukocytic CL as a function of dose than did A-PCP. Because of the probable roles of ROIs in antimicrobial blood cell-mediated mechanisms, reduced CL activity was interpreted as an indication of xenobiotic-induced immunosuppression.