title: Exposure to lead during critical windows of embryonic development: differential immunotoxic outcome based on stage of exposure and gender.
abstract: Previous rat studies with lead (Pb) have shown that exposure throughout the full gestational period results in persistent immunotoxicity detectable in both juvenile and adult offspring. Gender differences are also evident. However, little is known about the persistent immunotoxic effects of Pb when administered during specific stages of embryonic development. Adult Sprague-Dawley female rats were administered Pb acetate (or control acetate) in their drinking water early in gestation (days 3-9) or late in gestation (days 15-21). Significantly depressed delayed type hypersensitivity (DTH) responses as well as elevated IL-10 production, relative monocyte numbers, and increased relative thymic weights were observed in late-gestation Pb-exposed female offspring assessed as adults. In contrast, late-gestation Pb-treated male offspring had significantly increased IL-12 production and decreased IL-10 production, while the DTH response, relative monocyte numbers and thymic weights were unchanged. With early exposure, the primary alteration was decreased nitric oxide production in Pb-treated males, whereas in Pb-treated females nitrite production was unaltered. These results suggest that at the Pb dosage employed, the embryo may be more sensitive to the full range of Pb-induced immunotoxic effects with late gestational Pb exposure, and the effects of Pb on DTH function are more pronounced in females. The data also indicate that adherent splenocytes (probably macrophages) and T lymphocytes are the primary immune cells affected during fetal Pb exposure, and that gender may influence the impact of Pb exposure on these cells. Therefore, additional developmental immunotoxicity studies are needed to examine critical windows of immune development for immunotoxicity and differential susceptibility based on gender.
authors.affiliation: Department of Microbiology and Immunology, College of Veterinary Medicine, and Institute for Comparative and Environmental Toxicology, Cornell University, Ithaca, New York 14853-6401, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: Bunn
authors.forename: P J
authors.initials: PJ
authors.lastname: Parsons
authors.forename: E
authors.initials: E
authors.lastname: Kao
authors.forename: R R
authors.initials: RR
authors.lastname: Dietert
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D001842:Bone and Bones / Q000737:chemistry; D002478:Cells, Cultured; D003208:Concanavalin A / Q000276:immunology; D016207:Cytokines / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000187:drug effects*; D005314:Embryonic and Fetal Development; D005260:Female; D005865:Gestational Age; D006433:Hemocyanins / Q000276:immunology; D006968:Hypersensitivity, Delayed; D007371:Interferon-gamma / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D007854:Lead / Q000097:blood / Q000633:toxicity*; D007958:Leukocyte Count; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D009573:Nitrites / Q000378:metabolism; D009929:Organ Size; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000494:pharmacology / Q000633:toxicity*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012727:Sex Characteristics; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013950:Thymus Gland / Q000276:immunology / Q000502:physiology
chemical_list: D000276:Adjuvants, Immunologic; D016207:Cytokines; D007376:Interleukin-2; D008070:Lipopolysaccharides; D009573:Nitrites; D009942:Organometallic Compounds; D003208:Concanavalin A; D016753:Interleukin-10; D018664:Interleukin-12; D007854:Lead; D007371:Interferon-gamma; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin; C008261:lead acetate