Acute exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can suppress adaptive immunity. In this study, pre-exposure of Leishmania major-infected mice to TCDD caused a dose-dependent and unexpected decrease in parasite burdens on day 20 after infection. In contrast, TCDD-mediated lymphoid atrophy, suppressed antibody levels, and enhanced interleukin-2 production were observed as expected. T...

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a widespread environmental contaminant and prototypic ligand for the aryl hydrocarbon receptor, is a potent immunotoxicant. To understand the underlying mechanisms of TCDD immunotoxicity, we have characterized the time course of changes in CTL, alloantibody, and cytokine responses to the P815 tumor allograft in C57B1/6 mice treated with 0 or 15 microg...

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), an extraordinarily potent toxin, has recently been found to be a potent carcinogen producing mucosal, lung, and liver tumors in female rats. In light of this carcinogenicity, we reexamined the in vivo covalent binding of [3H]TCDD to rat liver macromolecules. Immature Sprague-Dawley rats, receiving [3H]TCDD (0.87 mCi/kg; specific activity, 39 Ci/mmol) ...

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), one of the components of Agent Orange, has been reported to be a deadly poison despite its presence at extremely small doses. TCDD is reported to cause various kinds of cancers and other harmful effects on humans. However, a correlation between exposure to TCDD and acute coronary syndrome (ACS) is not yet proven. Thus, we examined the correlation betw...

Changes in ethoxyresorufin-O-deethylase (EROD) activity were monitored through an extended 6-month dietary exposure to determine the relationship between EROD activity and uptake of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in brook trout, Salvelinus fontinalis. Brook trout were fed labeled TCDD during a 4-week loading phase and an 11-week maintenance phase to achieve whole-body concentrations...

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and structurally similar halogenated aromatic hydrocarbons cause a broad range of immunologic effects in experimental animals including decreased host resistance to infectious disease and suppressed humoral and cell-mediated immune responses. In the mouse, TCDD immunotoxicity has been shown to be an aryl hydrocarbon (Ah) receptor-dependent process. How...

We studied the effect of polychlorinated biphenyls (PCBs) on hepatic porphyrin accumulation in female Sprague-Dawley rats by feeding them diets containing 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153), 2,3,3',4,4',5-hexachlorobiphenyl (PCB 156), 3,3',4,4',5-pentachlorobiphenyl (PCB 126), or combinations of the single PCB congeners with TCDD for 13 weeks...

The environmental contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), causes immune suppression via activation of the aryl hydrocarbon receptor. Dendritic cells (DCs), the professional antigen-presenting cells in the immune system, are adversely affected by TCDD. We hypothesized that TCDD alters DC homeostasis, resulting in a loss of DCs in naive mice. To test this hypothesis, C57Bl/6 mice...

The immune response to influenza virus is exquisitely sensitive to suppression by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD); however, the cellular mechanisms underlying the suppressive effects of TCDD are unknown. Mice exposed to TCDD exhibited a dose-responsive increase in mortality following an otherwise non-lethal influenza virus infection. Given that cytotoxic T lymphocytes (CTL) are gener...

Prenatal exposure to TCDD interferes with fetal development at doses lower than those causing overt toxicity in adult animals. Exposure to TCDD during development produces alterations in the reproductive system of the developing pups- delayed puberty and reduced sperm counts in males and malformations in the external genitalia of females. The objectives of this study were to determine maternal ...