Regulatory T Cells Generated in Mice + CD 25 + Expression Analysis of CD 4 Functional Characterization and Gene (original) (raw)
Related papers
2008
Although the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are mediated through binding and activation of the aryl hydrocarbon receptor (AhR), the subsequent biochemical and molecular changes that confer immune suppression are not well understood. Mice exposed to TCDD during an acute B6-into-B6D2F1 graft-vs-host response do not develop disease, and recently this has been shown to correlate with the generation of CD4+ T cells that express CD25 and demonstrate in vitro suppressive function. The purpose of this study was to further characterize these CD4+ cells (TCDD-CD4+ cells) by comparing and contrasting them with both natural regulatory CD4+ T cells (T-regs) and vehicle-treated cells. Cellular anergy, suppressive functions, and cytokine production were examined. We found that TCDD-CD4+ cells actively proliferate in response to various stimuli but suppress IL-2 production and the proliferation of effector T cells. Like natural T-regs, TCDD-CD4+ cells do not produce IL-2 and ...
Toxicology and Applied Pharmacology, 2002
The cellular basis for the potent suppression of T cellmediated immune responses in mice following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is not fully understood. Although activation of the aryl hydrocarbon receptor (AhR) is required, the specific AhR ؉ cells that transduce the suppression have been difficult to identify in vivo. The recent availability of AhR ؊/؊ mutant mice has provided a resource for novel approaches to investigate the direct targets of TCDD. In our studies, we used an in vivo acute graft versus host (GVH) model of T cell immunity to address the direct AhR-dependent effects of TCDD on T cells. In this model, T cells from C57B1/6 mice are injected into C57B1/6 ؋ DBA/2 F1 host mice. The injected T cells recognize the MHC disparity of the host cells, resulting in the generation of an antihost cytotoxic T lymphocyte (CTL) response. By comparing the ability of TCDD to suppress the CTL response of T cells obtained from AhR ؉/؉ and AhR ؊/؊ C57B1/6 mice, the need for AhR expression in T cells themselves could be assessed. The results of these studies showed that the CTL response of T cells from AhR ؉/؉ mice was highly suppressed when the F1 host mice were treated with 15g/kg TCDD. TCDD treatment also protected the F1 host mice from the loss of body weight that accompanies the induction of the GVH response. In contrast, when grafted T cells were derived from AhR ؊/؊ mice, there was no suppression of the CTL response by TCDD, and the host animals lost significant body weight. Furthermore, when T cells from AhR ؉/؉ and AhR ؊/؊ mice were separated into CD4 ؉ and CD8 ؉ subsets and recombined using one subset from each donor prior to injection into the F1 host, suppression of the CTL response by TCDD was still apparent, but the degree of suppression was significantly reduced when either subset was AhR ؊/؊ . These results indicate that direct AhR-dependent effects of TCDD occur in both CD4 ؉ and CD8 ؉ T cell subsets and both T cell subsets contribute to the full suppression of the CTL response by TCDD. © 2002 Elsevier Science (USA)
Journal of immunotoxicology, 2008
Activation of aryl hydrocarbon receptor (AhR) by 2,3,7,8-tetracholordibenzo- p-dioxin (TCDD) during an acute graft-versus-host response induces a population of alloreactive donor CD4+CD25+ regulatory T (Treg)-like cells that have potent suppressive activity in vitro. In the present studies, we show that TCDD induced a similar population of donor CD8+CD25+ T-cells with suppressive activity in vitro. Like the CD4+ Treg cells, donor CD8+CD25+ T-cells also expressed higher levels of CD28, glucocorticoid-induced TNFR (GITR) and CTLA-4 along with low levels of CD62L. These TCDD-induced phenotypic changes were not observed if donor T-cells were obtained from AhR-KO mice. When CD4+ and CD8+ donor T-cells from AhR-WT and AhR-KO mice were injected in various combinations into F1 mice, the enhanced expression of CD25 on CD8+ T-cells required AhR in donor CD4+ T-cells, while down-regulation of CD62L required AhR in the donor CD8+ T-cells themselves. Changes in GITR and CTLA-4 on donor CD8+ T-ce...
2011
I understand that my project will become part of the permanent collection of the Oregon State University Library, and will become part of the Scholars Archive collection for BioResource Research. My signature below authorizes release of my project and thesis to any reader upon request. _________________________________ _______________ Laura Cristal Magaña Date 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a potent immunosuppressant and a prototypic ligand for the aryl hydrocarbon receptor (AhR). In a graft versus host (GvH) response, treatment with TCDD suppresses a cytotoxic T-lymphocyte (CTL) response by Day 10, concurrent with a T-regulatory (T reg) like phenotype in the donor CD4 + T-cells, observed on Day 2. The phenotype in CD4 + T-cells has been characterized as the following: CD25 high , CD62L low , CTLA-4 + , and IL-10 +. TCDD-mediated suppression may be due to the induction of this T-regulatory cell, which leads to altered cytokine production. In addition to IL-10, IFN-g also plays an important role in T cell differentiation. Previous experiments have measured the effects of TCDD on cytokine production only on day 2 of a GvH response. We were therefore interested in seeing if changes in cytokine production persist through day 3, when the T reg phenotype is still evident. We tested supernatants from prior GvH experiments to determine levels of these cytokines using enzyme-linked immunosorbent assays (ELISA). The results of these assays indicate no significant difference in IL-10 cytokine production between day 2 and day 3. However, on day 3, IFNg was increased in the supernatants of cells from TCDD-treated animals, indicating that TCDD up-regulated IFN-g production. There are other cytokines also produced by T regs , for example IL-2, IL-27 and TGF-b, which were not quantified and which could be involved in TCDD-mediated immunosuppression seen in a GvH model.
Toxicological Sciences, 2004
TCDD is a potent immunotoxicant that suppresses adaptive immunity by mechanisms that are not well defined. To gain insight at the level of the T cell, we used the DO11.10 transgenic T-cell receptor (TCR) mouse model in an adoptive transfer approach to characterize the influence of TCDD on the responsiveness of antigen-specific CD4 1 T cells in vivo. Flow cytometry was used to track the response of the OVA-specific transgenic CD4 1 T cells in syngeneic recipients using an antibody specific for the transgenic TCR (KJ1-26 [KJ]). Consistent with a previous report, exposure of the recipient mice to TCDD (15 mg/kg po) did not alter the initial expansion of the CD4 1 KJ 1 T cells in the spleen following immunization with OVA but resulted in a significant decline in the number of cells present on and after day 4. The degree of decline was dependent on the dose of TCDD. On day 3 after OVA injection, a higher percentage of the CD4 1 KJ 1 T cells in the spleens of TCDD-treated mice had down-regulated the expression of CD62L, a phenotype associated with T-cell activation. Also on day 3, an increased number of CD4 1 KJ 1 T cells were found in the blood of TCDD-treated mice. However, as in the spleen, the number of CD4 1 KJ 1 T cells in the blood rapidly declined on day 4. CD4 1 KJ 1 T cells in both the spleen and blood of TCDD-treated mice failed to up-regulate CD11a, an adhesion molecule important for sustained interaction between T cells and DC whereas the up-regulation of the adhesion molecule CD49d was not altered. Based on analysis of cell division history, CD4 1 KJ 1 T cells in vehicle-treated mice continued to divide through day 4 whereas CD4 1 KJ 1 T cells in TCDD-treated mice showed no further division after day 3. Increased annexin V staining on CD4 1 KJ 1 T cells in TCDD-treated mice was also observed but not until days 5 and 6. Fas-deficient CD4 1 KJ 1 T cells were depleted from the spleen of TCDD-treated mice in a manner similar to wildtype CD4 1 KJ 1 T cells, suggesting that Fas signaling does not play a critical role in this model. On the other hand, gene array analysis of purified CD4 1 KJ 1 T cells on day 3 showed that the expression of several genes associated with cell survival/death were altered by TCDD. Taken together, the results are consistent with our hypothesis that TCDD provides an early but inappropriate activation signal to the antigen-specific T cells that allows, and possibly enhances, the initial activation and proliferation of the T cells, yet at the same time, interferes with the vital expression of certain adhesion/costimulatory molecules that serve to enhance the survival of the T cells. These changes result in truncated proliferation, increased T-cell death, and suppression of the adaptive immune response.
Frontiers in immunology, 2012
Activation of the aryl hydrocarbon receptor (AhR) by its prototypic ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), mediates potent suppression of T-cell dependent immune responses. The suppressive effects of TCDD occur early during CD4(+) T-cell differentiation in the absence of effects on proliferation and have recently been associated with the induction of AhR-dependent regulatory T-cells (Treg). Since AhR functions as a ligand-activated transcription factor, changes in gene expression induced by TCDD during the early stages of CD4(+) T-cell differentiation are likely to reflect fundamental mechanisms of AhR action. A custom panel of genes associated with T-cell differentiation was used to query changes in gene expression induced by exposure to 1 nM TCDD. CD4(+) T-cells from AhR(+/+) and AhR(-/-) mice were cultured with cytokines known to polarize the differentiation of T-cells to various effector lineages. Treatment with TCDD induced the expression of Cyp1a1, Cyp1b1, and Ahr...
Nature Immunology, 2010
The aryl hydrocarbon receptor (AhR) participates in the differentiation of mouse regulatory T cells (T reg cells) and interleukin 17 (IL-17)-producing helper T cells (T H 17 cells), but its role in human T cell differentiation is unknown. We investigated the role of AhR in the differentiation of human induced T reg cells (iT reg cells). We found that AhR activation promoted the differentiation of CD4 + Foxp3 − T cells, which produce IL-10 and control responder T cells through granzyme B. However, activation of AhR in the presence of transforming growth factor-β1 induced Foxp3 + iT reg cells, which suppress responder T cells through the ectonucleoside triphosphate diphosphohydrolase CD39. The induction of functional Foxp3 + iT reg cells required coordinated action of the transcriptional regulators Smad1 and Aiolos. Thus, AhR is a potential target through which functional iT reg cells could be induced in human autoimmune disorders.