Environmental immunotoxicology

As observed in mammalian models, the immune system of fishes is a sensitive target organ system to evaluate toxicity. For a more thorough review of environmental immunotoxicology in fishes, with reference to specific classes of xenobiotics, readers are referred to several reviews that deal with the subject over a span of nearly three decades [45-47, 54-57], While fish in the environment may be exposed to a variety of xenobiotics, the most frequently investigated xenobiotics are the polycyclic aromatic hydrocarbons (PAHs) and halogenated aromatic hydrocarbons (HAHs) due to the presence and activation of the aryl hydrocarbon receptor (AhR) in fish, and heavy metals due to their ubiquitous environmental distribution. 

The majority of early publications that can be reasonably identified as comprising immunotoxicology reported altered resistance to infection in animals exposed to various environmental or industrial chemicals. Authors logically concluded that xenobiotic exposure suppressed immune function since the immune system is ultimately responsible for this resistance to infection. Subsequent studies demonstrated that suppression of various cellular and functional endpoints accompanied or preceded increased sensitivity to infection, and that administration of known immunosuppressants likewise decreased host resistance. The human health implications of these studies, that chemical exposure reduced resistance to infection, drove the initial focus of many immunotoxicologists on functional suppression, and provided the theoretical and practical underpinnings of immunotoxicity testing. 

Tryphonas H., The primate immune system (non-human) and environmental contaminants, in Encyclopedia of Immunotoxicology, Vohr, H.W., Ed., Springer Press, Heidelberg, 2005, 532-536. 

Similarly, data already available indicate that SNPs will be quite relevant in immunotoxicology and immunopharmacology. Findings that SNPs of immune-related proteins have an impact on the development of beryllium disease and silicosis suggest that SNPs may explain much of the daunting diversity of human responses to environmental and pharmaceutical agents. 

More recently, the National Institute of Environmental Health Sciences and the National Institute for Occupational Safety and Health convened a workshop in which experts in the field of developmental immunotoxicology developed a tiered approach for assaying the developmental immunotoxicity of chemicals.18 The recommended assays were separated into three groups (1) an initial set of screening assays, (2) assays for validation of a correlation between the assay end point and functional outcomes in humans, and (3) assays for research development.18 The initial screening assays included analysis of the primary antibody response to a T-dependent antigen, the delayed type... 

In one of the founding studies in immunotoxicology, Friend and Trainer [77] demonstrated that exposure to polychlorinated biphenyls (PCBs) increased mortality of mallard (Anas platyrhynchos) ducklings challenged with duck hepatitis virus. Since then the field of avian immunotoxicology has expanded to show that both the structure and function of the avian immune system often is affected by a diverse array of environmental contaminants, including heavy metals, pesticides, petroleum hydrocarbons, and organic industrial chemicals. Wild birds have proven to be excellent sentinel species for assess-... 

The vulnerability of marine mammals to environmental pollution provides an ecologically-relevant context for marine mammal immunotoxicology. Often situated at the top of aquatic food chains, marine mammals are exposed to high concentrations of a complex mixture of persistent contaminants, many of which are known to be immu-notoxic in laboratory animals. Marine mammal immunotoxicology came into its own in... 

Immunotoxicology Branch National Health and Environmental Effects Research Laboratory Environmental Protection Agency Research Triangle Park, NC 27711... 

Dean, J.H., Thurmond, L.M., Lauer, L.D. and House, R.V (1987). Comparative toxicology and correlative immunotoxicology in rodents. In Environmental Chemical Exposure and Immune System Integrity (Burger, E.J., Tardiff, R.G. and Bellanti, J.A., Eds.). Princeton Scientific Publishing, Princeton, pp. 265-271. 

Gleichmann, E., Kimber, I. and Purchase, I.F.H. (1989). Immunotoxicology suppressive and stimulatory effects of drugs and environmental chemicals on the immune system. Arch. Toxicol. 63 257-273. 

Luster Ml, Pfiefer RW, Tucker AN. 1985. The immunotoxicity of natural and environmental estrogens. In Dean JH, ed. Target organ toxicology series Immunotoxicology and immunopharmacology. New York, NY Raven Press Book Inc., 315-326. 

Patandin S, Koopman-Esseboom C, de Riddr MA, et al. Effects of environmental exposure to polychlorinated biphenyls and dioxins on birth size and growth in Dutch children. Pedeatr Res 1998 44(4) 538-45.Kim HA, Kim EM, Park YC, et al. Immunotoxicological effects of Agent Orange exposure to the Vietnam War Korean veterans. Ind Health 2003 41(3) 158-66. 

Immunotoxicology Branch, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711... 

---