Papers by Nancy Kerkvliet
Immunotoxicology of Dioxins and Related Chemicals
John Wiley & Sons, Inc. eBooks, Jan 28, 2005
Journal of Immunology, Sep 15, 1996
Involvement of altered B7 expression in dioxin immunotoxicity: B7 transfection restores the CTL b... more Involvement of altered B7 expression in dioxin immunotoxicity: B7 transfection restores the CTL but not the autoantibody response to the P815 mastocytoma.
Suppressor Cells
Springer eBooks, Jun 23, 2015
Cytotoxic T Cells*
Elsevier eBooks, 2010
Cytotoxic T lymphocytes (CTLs) represent one of several types of cells of the immune system that ... more Cytotoxic T lymphocytes (CTLs) represent one of several types of cells of the immune system that have the capacity to directly kill other cells. They play a major role in host defense against viral infection, as well as infection by other intracellular pathogens that replicate in the cytoplasm of the host cell. Clinically important infections in which CTLs are regarded as a vital defense mechanism include human immunodeficiency virus (HIV)-1 (Carmichael et al. 1993; Koup et al. 1991), cytomegalovirus (Riddell et al. 1992), influenza (McMichael et al. 1983), hepatitis B (Bertoletti et al. 1994; Penna et al. 1991), and malaria (Hill et al. 1992). CTLs are also recognized as critical components of antitumor immunity (Roth et al. 1994). Due to the important functions that CTLs play in the immune system, assays of CTL activity have become an integral component of immunotoxicity assessment. This chapter will review the understanding of CTL development and functions, methods for assessing CTL functions, and the mechanisms by which drugs and other xenobiotic chemicals suppress CTL activity.
Annals of the New York Academy of Sciences, Jun 1, 1990
Measurements of immunity and modifications by toxicants
Dioxin intoxication from chronic exposure of horses to pentachlorophenol-contaminated wood shavings
PubMed, Jul 15, 1992
Investigations into the cause of health problems on a horse-breeding farm led to the discovery of... more Investigations into the cause of health problems on a horse-breeding farm led to the discovery of high concentrations (630 to 9,810 mg/kg of bedding) of pentachlorophenol in wood shavings used as bedding for horses over a period of 2 to 4 years. Toxicologic signs in the horses were characteristic of toxic effects associated with exposure of polychlorinated dibenzo-p-dioxins and dibenzofurans. Tissue residue analysis confirmed presence of toxic polychlorinated dibenzo-p-dioxin and dibenzofuran isomers known to be in pentachlorophenol, substantiating the bioavailability of polychlorinated dibenzo-p-dioxins and dibenzofurans in the wood shavings. The findings provide evidence that residue concentrations in the range of 2 ng/g of toxic polychlorinated dibenzo-p-dioxin isomers in liver or fat correlate with toxicologic effects in horses.
Characterization of the microbiome in association with reduced diabetes incidence in AhR deficient NOD mice
The Journal of Immunology
AhR activation by the ligands TCDD and Cl-BBQ leads to potent immunosuppression and prevents hype... more AhR activation by the ligands TCDD and Cl-BBQ leads to potent immunosuppression and prevents hyperglycemia in NOD mice. In addition to exogenous treatment, AhR can be activated by endogenous ligands that control inflammation. AhR−/− mice on the C57Bl6 background have enhanced inflammatory responses following infectious or allergenic exposure in comparison to AhR wild type mice. We generated AhR−/− mice on the NOD background and hypothesized they would display an increased incidence of diabetes. Surprisingly, the opposite finding was observed; in the absence of AhR, female NOD mice have a significantly reduced onset of diabetes in comparison to wild type mice. A similar trend was observed between knockout and wild type male mice. While immune cell composition was unchanged in the pancreatic LN, an increase in the percentage of F4/80+ macrophages and CD25+Foxp3+ T cells was observed in mesenteric LN of NOD.AhR−/− mice. Changes in gene expression in the ileum of NOD.AhR−/− mice include...
Immunotoxicity of the Pyrrolizidine Alkaloid Monocrotaline following Subchronic Administration to C57BI/6 Mice
Toxicological Sciences, 1990
Monocrotaline (MCT) is a member of a class of compounds known as pyrrolizidine alkaloids (PAs). P... more Monocrotaline (MCT) is a member of a class of compounds known as pyrrolizidine alkaloids (PAs). PAs are found in the leaves and seeds of a variety of plant species. The potential intoxication of livestock and man through the ingestion of contaminated grains and other foods makes PAs a significant toxicological concern. MCT exposure in rats results in lesions to hepatic and cardiopulmonary tissues as well as alterations in lymphoid organ cellularity. However, no previous studies have investigated MCT-induced functional alterations in the immune system. In the present study, MCT was administered by gavage for 14 days at 0, 10, 25, 50, 75, and 150 mg/kg to female C57Bl/6 mice. The antibody-mediated immune response to sheep red blood cells (SRBC) was assessed using the plaque-forming cell (PFC) assay and the hemolytic antibody isotope release assay (HAIR). Additionally, the cytotoxic T-lymphocyte (CTL) response to allogeneic P815 tumor cells was determined after MCT exposure. Although hepatic and pulmonary lesions are common sequelae to MCT exposure in rats, the C57Bl/6 mouse appeared to be more resistant to these effects on the basis of histopathological examination. Furthermore, the overt toxicity of MCT was minimal with respect to organ weight changes in liver, kidney, and lung. In contrast, a dose-dependent suppression in the antibody response to SRBC was observed with a minimum significant dose of 25 mg/kg. At this dose the number of anti-SRBC PFC per 10(6) spleen cells and the amount of anti-SRBC antibody measured in the HAIR assay were 57 and 59% of control, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
2,3,7,8-Tetrachlorodibenzo-p-dioxin Induction of Cytochrome P450-Dependent Arachidonic Acid Metabolism in Mouse Liver Microsomes: Evidence for Species-Specific Differences in Responses
Toxicology and Applied Pharmacology, Nov 1, 1998
Arachidonic acid is biotransformed to metabolites active in signal transduction by cytochrome P45... more Arachidonic acid is biotransformed to metabolites active in signal transduction by cytochrome P450 (CYP) as well as by cyclooxygenase and lipoxygenase enzymes. Inducers of CYP1 enzymes, including 2,3,7,8-tetrachlorodibenzo-p-dioxin and other Ah receptor ligands, markedly increase liver microsomal CYP-dependent arachidonic acid epoxygenation in chicks but depress epoxygenation in rat liver microsomes where they elicit about twofold increases in formation of other CYP products, omega-1 to omega-4-OH arachidonic acid. These studies examined the effect of TCDD on metabolism of [1-14C]-labeled arachidonic acid by mouse liver microsomes. Mouse liver microsomes metabolized arachidonic acid exclusively by a CYP-dependent mechanism as evidenced by lack of metabolism in the absence of NADPH and by formation of specific CYP-dependent metabolites. The major constitutive products were epoxygenase products (EETs and EET-diols) and omega-OH arachidonic acid. Treatment with TCDD increased formation of omega-2- to omega-4-OH arachidonic acid products 23-fold, formation of omega-1-OH arachidonic acid about 5-fold, and formation of epoxygenase products and HETEs each about twofold. In contrast, TCDD treatment decreased formation of omega-OH arachidonic acid by over 70%. EET-diols comprised a greater fraction of total epoxygenase products in mouse liver microsomes than has been found for liver microsomes of other species. The high EET-diol formation was attributable to a non-TCDD-inducible, EET epoxide hydrolase activity in mouse liver microsomes. For comparison, the effect of TCDD on [1-14C]-labeled arachidonic acid was examined in homogenates of spleen, an immune system target of TCDD. While levels of total [1-14C]-arachidonic acid metabolism were comparable in both tissues, virtually all of the metabolism by spleen was CYP-independent, and it was unaffected by TCDD. Western blotting experiments showed that TCDD-induced mouse Cyp1a1 and 1a2 share immunologic epitopes with chick CYP1A4 and 1A5. However, in immunoinhibition studies, an antibody to CYP1A5, the chick arachidonate epoxygenase, was ineffective against TCDD-induced arachidonic acid metabolism in mouse liver microsomes, suggesting that there are differences in the catalytic sites or tertiary structures of CYP1A5 and the CYP-enzyme catalyzing the TCDD-induced arachidonic acid metabolism in mouse liver. This study shows that the effects of TCDD of the profile of CYP-dependent arachidonic acid metabolities and the amounts produced in mouse liver microsomes differ from other species. The findings suggest that species differences in CYP1A catalytic activities including the metabolism of arachidonic acid may contribute to species differences in sensitivity to TCDD toxicity.
Cellular Immunology, May 1, 1984
The effect of vitamin B6 on cytotoxic immune responses of T cells, natural killer (NK) cells, cyt... more The effect of vitamin B6 on cytotoxic immune responses of T cells, natural killer (NK) cells, cytotoxic antibody production, and macrophage phagocytosis was assessed in 5-week-old female C57Bl/6 mice. Mice were fed 20% casein diets with pyridoxine (PN) added at 7, 1, 0.1, or 0 mg/kg diet, which represents 700, 100, 10, and 0% of requirement, respectively. Compared to mice fed 7 or 1 mg PN diet, animals fed 0 or 0.1 mg PN diet showed significantly reduced primary splenic and peritoneal T-cell-mediated cytotoxicity (CMC). Animals fed 0 mg PN diet also showed significantly depressed secondary T CMC of splenic and peritoneal lymphocytes against P8 15 tumor cells. Complement-dependent antibody-mediated cytotoxicity against P8 15 cells, phagocytosis of SRBC by macrophages, and native and interferon-induced NK cell activities against YAC cells were not affected by the level of vitamin & intake. The percentage of macrophages present in the peritoneal exudate cells was increased in animals fed the 0 mg PN diet. The immune responses were not enhanced or altered by the excess intake of vitamin Bs (7 mg PN). It appears that vitamin B6 is an essential nutrient for maintenance of normal T-cell function in vivo.
Leflunomide mediated inhibition of A375 melanoma cells is significantly dependent upon AhR expression
PLOS ONE, Feb 20, 2013
<p>(A) Viability of A375-pTRIPZ-shAhR melanoma cells treated with the indicated doses of le... more <p>(A) Viability of A375-pTRIPZ-shAhR melanoma cells treated with the indicated doses of leflunomide in the absence (AhR-expressing) or presence (AhR-knockdown) of 2 µg/mL doxycycline. Results are the mean ± SD of three independent experiments. N = 6; * P<0.0001 compared to respective dose of leflunomide in the absence of doxycycline. (B) Phase-contrast microscopy images of A375-pTRIPZ-shAhR cells treated with either vehicle or leflunomide (100 µM) for 72 hours in the absence or presence of doxycycline. (C) Real time cellular analysis of A375-pTRIPZ-shAhR proliferation with or without AhR knockdown in the presence of vehicle (0.1% v/v DMSO) or leflunomide at concentrations of 100, 50, or 25 µM. Data are the mean of two biological replicates and are representative of two independent experiments. (D) Cell index values at the end of the real-time analysis period (§) were evaluated by ANOVA.</p
Tetrachlorodibenzo--dioxin (TCDD) and 3,3′,4,4′,5,5′,-hexachlorobiphenyl (HxCB) enhance anti-CD3-induced T cell activation
Chemosphere, Jul 1, 1992
Abstract The effect of two immunosuppressive halogenated aromatic hydrocarbons (HAH), TCDD and Hx... more Abstract The effect of two immunosuppressive halogenated aromatic hydrocarbons (HAH), TCDD and HxCB, on T cell activation in vivo were evaluated using the monoclonal antibody (145-2C11) to the CD3 portion of the murine T cell receptor complex. Briefly, mice were injected in both rear footpads with either 25 μg anti-CD3 or hamster IgG. After 24 hr, popliteal and inguinal lymph node cells were pooled, and T cell activation was measured by 3H-TdR incorporation and flow cytometric analyses (DNA cell cycle; CD3 and IL-2 receptor (IL-2R) expression). The immunosuppressive drug, cyclosporin A (CsA, 50 mg/kg, ip), was used as a positive control. CsA inhibited anti-CD3-induced 3H-TdR incorporation, IL-2-driven 3H-TdR incorporation, and IL-2 receptor (IL-2R) expression. In contrast, TCDD (2 or 20 μg/kg, po) dose-dependently increased anti-CD3-induced 3H-TdR incorporation and the percentage of both CD4+ and CD8+ cells cycling in S/G2M. In addition, IL-2-driven 3H-TdR incorporation increased without an increase in IL-2R expression. Similar increases in anti-CD3-induced T cell activation were observed following HxCB treatment (30 mg/kg, po).
International Journal of Immunopharmacology, 1993
Abstraet-An in vivo model was used to examine the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (... more Abstraet-An in vivo model was used to examine the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on various parameters of T-cell activation. In this model, the hamster anti-mouse monoclonal antibody 145-2C11 (anti-CD3) to the CD3 portion of the murine T-cell receptor was injected into both rear footpads of female C57B1/6 mice and the draining popliteal and inguinal lymph node cells (LNC) were removed 24 h later. Cyclosporin A (CsA) was included as a known immunosuppressive control. As expected, CsA (50 mg/kg, i.p.) suppressed anti-CD3-induced proliferation, IL-2-driven 3H-TdR incorporation, and IL-2R expression. In contrast, TCDD unexpectedly enhanced anti-CD3-induced ~H-TdR incorporation. Flow cytometric analysis showed that TCDD treatment increased the percentage of both CD4 + and CD8 + cells cycling in S and G2M. LNC from TCDD-treated mice also had enhanced 3H-TdR incorporation when cultured in the presence of a saturating amount of exogenous raiL-2. TCDD did not significantly alter the percent positive or the number of IL-2 receptors (IL-2R) on either CD4 ÷ or CD8 + cells when examined at several time points after anti-CD3 treatment. Both the kinetics and extent of anti-CD3-induced downmodulation of CD3 expression on CD4 + and CD8 ÷ cells was unaffected by TCDD. TCDD alone did not result in enhanced 3H-TdR incorporation, cell cycling or IL-2R expression. Therefore, TCDD appears to be targeting T-cells that are undergoing activation rather than resting cells. The strength of the anti-CD3 model is evidenced by the fact that two known immunosuppressive compounds (CsA and TCDD) have distinct and opposite effects on T-cell activation. These findings suggest that the mechanism(s) by which CsA and TCDD impair T-cell function are different.
Oncogene, Jan 13, 2015
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor and a member of th... more The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor and a member of the basic helix-loop-helix PER/ARNT/SIM family of chemosensors and developmental regulators. The AhR is widely known as a mediator of dioxin toxicity; however, it also suppresses cancer cell proliferation and recent findings have implicated its role as a tumor suppressor. We conducted a chemical library screen to identify nontoxic AhR ligands with anti-cancer effects and discovered flutamide (Eulexin) as a putative AhR ligand. Flutamide is an androgen receptor (AR) antagonist approved by the United States Food and Drug Administration for the treatment of prostate cancer. We found that flutamide inhibited the growth of several cancer cell lines independent of AR status, and that suppression of AhR expression reversed the anti-proliferative effects of flutamide. We investigated the AhR-dependent mechanism of action of flutamide in human hepatocellular carcinoma cells and identified that tran...
Distribution of 2,3,7,8-tetrachlorodibenzo-p-dioxin in splenic tissue of C57BL/6J mice
Drug metabolism and disposition: the biological fate of chemicals
Toxicology and Applied Pharmacology, 1982
Adult male C57B1/6 mice were fed diets containing 50 or 500 ppm pure (99+%) or technical grade (8... more Adult male C57B1/6 mice were fed diets containing 50 or 500 ppm pure (99+%) or technical grade (86%) pentachlorophenol (PCP) for lo-12 weeks prior to assessment of immunocompetence. Assays for immunocompetence included in vivo host susceptibility to virus infection and tumor growth and in vitro quantitation of T-cell cytotoxicity and macrophage phagocytosis. Exposure of mice to technical PCP resulted in profound enhancement of tumor susceptibility. The incidence of progressive methylcholanthrene (MCA)-induced transplanted tumors increased from 35% in controls to 67 and 82% in animals exposed to 50 and 500 ppm technical PCP, respectively. Mortality following primary Moloney sarcoma virus (MSV) inoculation and secondary MSB challenge increased from 19% in controls to 45 and 73% in animals exposed to 50 and 500 ppm technical PCP, respectively. An additional 50% of the MSV/MSB challenged mice exposed to 50 ppm technical PCP exhibited tumor dissemination in the spleen. Animals exposed to pure PCP did not exhibit enhancement of primary MCA-or MSV-induced tumor growth. However, splenic tumor development was observed in 22 and 44% of the MSV/MSB challenged mice exposed to 50 and 500 ppm pure PCP, respectively. Control mice did not develop splenic tumors. In contrast to the enhancement of tumor susceptibility, mortality associated with encephalomyocarditis virus infection tended to be reduced by technical PCP exposure. In vitro immune functional assessment indicated significant depression in T-cell cytolytic activity and enhancement of macrophage phagocytosis in animals exposed to technical PCP. No significant changes in in vitro immune response were noted with cells from pure PCPexposed animals.
Modulation of host immune responses by Fasciola hepatica: responses by peripheral lymphocytes to mitogens during liver fluke infections of sheep
PubMed, Jun 1, 1983
Fasciola hepatica infections of lambs (250 or 500 metacercariae) were shown to alter the prolifer... more Fasciola hepatica infections of lambs (250 or 500 metacercariae) were shown to alter the proliferative responses of peripheral blood lymphocytes (whole blood culture) to mitogens at specific times postinfection (PI). Responses to concanavalin A (Con A) were significantly suppressed at weeks 4, 8, 10, and 11 PI whereas suppressed responses to phytohemagglutinin (PHA) occurred at weeks 4, 10, 11, and 16 PI. Only on weeks 4 and 6 PI were responses to pokeweed mitogen (PWM) suppressed. The fluke-induced modulation of responses appeared to be related more to specific phases of infection rather than to worm burdens.
Modulation of Host Immune Responses by Fasciola hepatica: Responses of Peripheral Lymphocytes to Mitogens during Liver Fluke Infections of Sheep
Journal of Parasitology, Jun 1, 1983
Fasciola hepatica infections of lambs (250 or 500 metacercariae) were shown to alter the prolifer... more Fasciola hepatica infections of lambs (250 or 500 metacercariae) were shown to alter the proliferative responses of peripheral blood lymphocytes (whole blood culture) to mitogens at specific times postinfection (PI). Responses to concanavalin A (Con A) were significantly suppressed at weeks 4, 8, 10, and 11 PI whereas suppressed responses to phytohemagglutinin (PHA) occurred at weeks 4, 10, 11, and 16 PI. Only on weeks 4 and 6 PI were responses to pokeweed mitogen (PWM) suppressed. The fluke-induced modulation of responses appeared to be related more to specific phases of infection rather than to worm burdens.
Uploads
Papers by Nancy Kerkvliet