Articles: regulatory-t-lymphocytes.
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J. Reprod. Immunol. · Oct 2007
Fetal alloantigen is responsible for the expansion of the CD4(+)CD25(+) regulatory T cell pool during pregnancy.
Increasing evidence suggests that CD4(+)CD25(+) regulatory T cells (Tregs) participate in the development of maternal tolerance to the fetus during pregnancy; however, the factors controlling the activities of Tregs are poorly understood. In the present study, CD4(+)CD25(+) Tregs were analyzed in syngeneically pregnant mice (BALB/cxBALB/c), allogeneically pregnant mice (BALB/cxC57), ovariectomized mice and pregnant women to investigate the influences of fetal alloantigens and pregnancy-related hormones on the activities of Tregs. It was demonstrated that the frequencies of CD4(+)CD25(+) Tregs increase more in allogeneically than in syngeneically pregnant mice, which contributes to a lowered alloreactivity against paternal antigens in allogeneically compared with syngeneically pregnant mice. ⋯ Induction of labor in humans appears to be associated with a decrease of CD4(+)CD25(high) Tregs and increase of CD4(+)CD25(low) T cells. Neither estrogen or progesterone alone, nor their combination, shows an impact on the frequencies of Tregs in ovariectomized mice. These results suggest that fetal alloantigen is responsible for the increase of Tregs during pregnancy, and the expansion of the Treg population is of importance for the allogeneic fetus to evade immune attack from the mother.
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The forkhead family transcription factor Foxp3 is critical for the development and function of CD4(+)CD25(+) regulatory T cells (Tregs). A series of reports have begun to shed light on the precise role of Foxp3 in the regulation of the Treg transcriptome. Foxp3 can bind to specific gene elements, thereby altering transcription of target genes directly, and Foxp3 can alter the expression of genes encoding other transcription factors, thereby having an indirect effect on the transcription of target genes. Cells retaining aspects of Treg differentiation persist in the absence of Foxp3, which is suggestive of a Foxp3-independent aspect of Treg biology.
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Xenotransplantation · Jul 2007
Characterization and expansion of baboon CD4+CD25+ Treg cells for potential use in a non-human primate xenotransplantation model.
It is well established that CD4(+)CD25(+) regulatory T (Treg) cells can modulate allogeneic immune responses. Xenotransplantation, proposed as a means to address the critical shortage of human organs, may also benefit from similar approaches to avert rejection. Baboons are a preferred preclinical animal model for xenogeneic organ transplantation experiments, and the characterization of baboon Treg cells will be beneficial to future tolerance studies in this animal model. ⋯ We demonstrate that baboon Treg cells suppress immune responses to xenogeneic stimulation. These studies suggest that adoptive transfer of expanded Treg cells into transplant recipients may provide an approach to prevent cell-mediated rejection of grafts and potentially induce tolerance in the pig to baboon xenotransplantation preclinical model.
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The vast majority of clinical and basic science research on the immune consequences of burn injury and sepsis conducted during the last three decades has focused mainly on the roles of macrophages, neutrophils and, to a lesser extent, conventional T lymphocytes. During recent years, however, it has become increasingly clear that minor subsets of innate immune cells, innate regulatory lymphocytes in particular, are central to processes involved in both protective immunity and immunopathology. ⋯ Given their emerging importance and documented upstream regulatory capacities over macrophage, dendritic cell, and T lymphocyte functions, innate regulatory lymphocytes represent attractive new targets for therapeutic intervention for the overall immune paralysis that occurs with injury and sepsis. Here, we provide an overview of the current state of knowledge of these particular cell subsets in the immune response to burn injury and sepsis.
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Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi · May 2007
[Analysis of Foxp3+ CD4+ CD25+ regulatory cells in peripheral blood of patients with SLE].
To investigate the expression of GITR on T cells and the expression of Foxp3(+) CD4(+) CD25(+) regulatory T cells in the peripheral blood of patients with SLE. ⋯ The expression abnormality of both Foxp3(+) CD4(+) CD25(+) regulatory cells and GITR may play important role in the imbalance of immune homeostasis in SLE.