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Interaction of a single dose (36 mg/kg body wt) of the organochlorine pesticide dieldrin with mouse peritoneal macrophages was examined in C57Bl/6, (C57Bl/6 X A/J)F1, and A/J strains of different genetic resistance to mouse hepatitis virus 3 (MHV3) infection. In vivo studies showed increased susceptibility to MHV3 acute disease of C57Bl/6 and (C57Bl/6 X A/J)F1 animals challenged with the pesticide. Significant decrease of mean time of death in dieldrin-exposed, MHV3-infected susceptible C57Bl/6 mice was observed similarly upon po or ip administration of a single, sublethal dose of dieldrin. In addition, decrease of humoral response to the virus was quantified by determination of anti-MHV3 IgG antibodies in spleen cell supernatant fractions and in blood sera of dieldrin-exposed C57Bl/6 mice. A single dose of dieldrin did not alter the in vivo resistance of A/J animals to acute MHV3 disease. The resistant A/J mice, however, showed increased mortality upon two subsequent exposures to dieldrin followed by infection with high lethal doses of MHV3. Phagocytic activity, cell adherence capacity, and attachment and uptake of 3H-radiolabeled MHV3 by C57Bl/6 peritoneal macrophages were determined by in vitro studies. These affector activities of peritoneal macrophages were slightly decreased or unchanged in cells originating from animals exposed to the pesticide. However, the intrinsic activity of MHV3 restriction appeared to be affected in macrophages derived from dieldrin-treated animals: (i) peritoneal C57Bl/6 macrophages collected from the early phase of acute MHV3 disease contained increased MHV3 antigen and (ii) increased cytolysis was observed after in vitro MHV3 infection of macrophages originating from dieldrin-exposed C57Bl/6 mice.

Cement kiln dusts are made of a complex mixture of elements. We have evaluated the potential negative impact of those dusts on the immune system of the earthworm Lumbricus terrestris. We specifically studied cell viability and phagocytic activity of coelomocytes extruded during electrical stimulation. We used two modes of exposures: in vitro, and soil incubation using OECD artificial soil media. Extruded coelomocytes were exposed 18 h in vitro to 10, 100, and 500 mg L-1 of cement kiln dust particles. The phagocytosis and the cell viability were determined using a double-laser-flow acquisition cytometry system. Using the double laser allows us to use a dichlorofluorescein diacetate (DCFDA) marker to discriminate the biological cells from the cement kiln dusts. Dead cells are marked using propidium iodide (PI). All three exposure levels showed highly significant impacts on cell viability and phagocytic activity. The in vivo soil incubation was performed using 10, 100, and 1000 mg kg-1 of cement kiln dusts incorporated into the OECD media. Here, to discriminate the biological cells from the mineral dusts we only needed to use PI. The day-to-day variability of the in vivo assay was high and although we can observe an overall reduction in cell viability at the highest concentration tested, no statistically significant effects could be observed on either cell viability or phagocytosis. Copyright 2004 Elsevier Inc. All rights reserved.

Aquat. Toxicol. ISI Document Delivery No.: NX445 Times Cited: 30 Cited Reference Count: 25 Voccia, i krzystyniak, k dunier, m flipo, d fournier, m Elsevier science bv Amsterdam; Cytotoxic and immunotoxic effects of mercury chloride and methylmercury on blood and head kidney leucocytes of rainbow trout (Oncorhynchus mykiss) were evaluated in vitro, for a broad dose range (10(-4)-10(-9) M Hg) of the chemicals. Mercury-related impairment of functional cellular parameters were measured using mixed leucocyte reaction (MLR) and mitogen stimulation of the cells by phytohaemagglutinin (PHA), concanavalin A (Con A) and lipopolysaccharide (LPS). Non-specific defense mechanisms of blood neutrophils and pronephros macrophages were analysed using flow cytometric assay of phagocytosis and respiratory burst. Impairment of the functional cellular activities appeared to be limited almost exclusively to cytotoxic concentrations of the mercurials. Similarly, phagocytic and respiratory burst activities of blood and head kidney phagocytes were markedly impaired by high, cytotoxic concentrations of the mercurials. The in vitro cytotoxic potential of methylmercury; greater-than-or-equal-to 10(-5) M Hg, appeared to be at least ten times higher over the cytotoxicity of mercury chloride greater-than-or-equal-to 10(-4) M Hg. At lower mercury concentrations, the data showed mostly normal- or above-normal values of the assayed functional activities of the cells. Overall, a nonspecific, poisoning-related impairment of leucocyte and phagocyte functions was concluded for the in vitro cytotoxic concentrations of mercurials.