Aquatic Pollution-Induced Immunotoxicity in Wildlife Species

Abstract

The potential for chemicals to adversely affect human immunologic health has traditionally been evaluated in rodents, under laboratory conditions. These laboratory studies have generated valuable hazard identification and immunotoxicologic mechanism data; however, genetically diverse populations exposed in the wild may better reflect both human exposure conditions and may provide insight into potential immunotoxic effects in humans. In addition, comparative studies of species occupying reference and impacted sites provide important information on the effects of environmental pollution on the immunologic health of wildlife populations. In this symposium overview, Peter Hodson describes physiological changes in fish collected above or below the outflows of paper mills discharging effluent from the bleaching process (BKME). Effects attributable to BKME were identified, as were physiological changes attributable to other environmental factors. In this context, he discussed the problems of identifying true cause and effect relationships in field studies. Mohamed Faisal described changes in immune function of fish collected from areas with high levels of polyaromatic hydrocarbon contamination. His studies identified a contaminant-related decreases in the ability of anterior kidney leukocytes to bind to and kill tumor cell line targets, as well as changes in lymphocyte proliferation in response to mitogens. Altered proliferative responses offish from the contaminated site were partially reversed by maintaining fish in water from the reference site. Peter Ross described studies in which harbor seals were fed herring obtained from relatively clean (Atlantic Ocean) ' Symposium held at the 35th Annual Meeting of the Society of Toxicology (SOT), Anaheim, CA. Sponsored by the lmmunotoxicology Specialty Section of the SOT.2 To whom correspondence should be addressed at Mail Drop 92, U.S. EPA, Research Triangle Park, NC 27711. E-mail: luebke.robert® epamail.epa.gov.3 Present address: Contaminant Sciences Section, Institute of Ocean Sciences, P.O. Box 6000, Sidney, BC, Canada V8L 4B2. and contaminated (Baltic Sea) waters. Decreased natural killer cell activity and lymphoproliferative responses to T and B cell mitogens, as well as depressed antibody and delayed hypersensitivity responses to injected antigens, were identified in seals fed contaminated herring. In laboratory studies, it was determined that rats fed freeze-dried Baltic Sea herring had higher virus titers after challenge with rat cytomegalovirus (RCMV) than rats fed Atlantic Ocean herring; perinatal exposure of rats to oil extracted from Baltic herring also reduced the response to challenge with RCMV. Keith Grassman reported an association between exposure to polyhalogenated aryl hydrocarbons and decreased T cell immunity in the offspring of fish-eating birds (herring gulls and Capsian terns) at highly contaminated sites in the Great Lakes. The greatest suppression of skin test responses to phytohemagglutinin injection (an indicator of T cell immunity) was consis...

Effect of copper sulfate on the survival and growth performance of Caspian Sea kutum, Rutilus frisii kutum

“…Chronic exposure of fish to water-borne Cu, Cd or Zn has been shown to cause a variety of physiological and behavioral changes including loss of appetite, reduced growth, ionic loss and increased fish mortality (Scherer 1997). Heavy metal contamination usually causes depletion in feed utilization in fish and such disturbance may result in reduced fish metabolic rate and hence causing reduction in their growth (Javed 2005).…”

Evolution of tolerance to PCBs and susceptibility to a bacterial pathogen (Vibrio harveyi) in Atlantic killifish (Fundulus heteroclitus) from New Bedford (MA, USA) harbor

“…Due to increased energetic demands, e.g., from gamete production and mating behavior, and a complex interplay between stress and reproductive hormones and the immune system, spawning is often considered a period of increased vulnerability to disease and other stressors in fishes (e.g., Luebke et al 1997; Schreck 1996; Tatner 1996; Harris and Bird 2000; Maule et al 1996; Yada and Nakanishi 2002). Other endocrine factors that may also vary seasonally, such as thyroid hormone, have been shown to affect immune response in killifish and other fish (Yada and Nakanishi 2002).…”

Genetic diversity of the major histocompatibility complex of cotton rats (Sigmodon hispidus) inhabiting an oil refinery complex

“…As noted by Bickham and Smolen [1], it is important to understand all levels at which environmental contaminants affect populations, from the molecular level to the population level. Immunocompetence has been used successfully as a biomarker at the individual level, and effects of environmental contamination on immunologic health of wildlife species have been relatively well documented [16,17,45,46]. If alterations in immunocompetence documented by studies such as these result in loss of genetic diversity or selection for certain genotypes, this would represent population‐level effects of evolutionary change, adding another important component to our understanding of the impact of environmental contaminants.…”