| Development of the Murine and Human Immune System: Differential Effects of Immunotoxicants Depend on Time of Exposure Steven D. Holladay1 and Ralph J. Smialowicz2 1Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA; 2Environmental Research Center, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA Abstract Fetal and early postnatal life represent critical periods in vertebrate immune system development. Disruption of such development by perinatal immunotoxic chemical exposure has been widely described in experimental animal models. The resultant inhibited postnatal immune responses in such animals are often more dramatic and persistent than those after exposure during adult life. Further, recent reports suggest that prenatal exposure to immunotoxicants may exacerbate postnatal aberrant immune responses (e.g., hypersensitivity disorders and autoimmune disease) in genetically predisposed rodents. Limited information is available regarding the possibility of inhibited postnatal immune capacity in humans as a result of developmental immunotoxicant exposure. The multifactorial nature of hypersensitivity and autoimmune responses will further complicate the elucidation of possible relationships between chemical exposure during ontogeny of the human immune system and immune-mediated disease later in life. Taken together, however, the available animal data suggest the potential for altered postnatal immune function in humans exposed to immunotoxicants (e.g., environmental chemicals and therapeutic agents) during fetal and/or early postnatal life. Key words: autoimmune disease, developmental immunotoxicity, diethylstilbestrol, immune development, TCDD, 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin, prenatal, therapeutic immunosuppressant. -- Environ Health Perspect 108(suppl 3) :463-473 (2000) . http://ehpnet1.niehs.nih.gov/docs/2000/suppl-3/463-473holladay/abstract.html The full version of this article is available for free in HTML format. |