Examinando por Autor "Tejon, Gabriela"

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    Alloreactive regulatory T cells generated with retinoic acid prevent skin allograft rejection
    (Wiley-VCH Verlag, 2015-02) Moore, Carolina; Tejon, Gabriela; Fuentes, Camila; Hidalgo, Yessia; Bono, Maria R.; Maldonado, Paula; Fernandez, Ricardo; Wood, Kathryn J.; Fierro, Juan A.; Rosemblatt, Mario; Sauma, Daniela; Bushell, Andrew
    CD4+CD25+Foxp3+ regulatory T (Treg) cells mediate immunological self-tolerance and suppress immune responses. Retinoic acid (RA), a natural metabolite of vitamin A, has been reported to enhance the differentiation of Treg cells in the presence of TGF-β. In this study, we show that the co-culture of naive T cells from C57BL/6 mice with allogeneic antigen-presenting cells (APCs) from BALB/c mice in the presence of TGF-β, RA, and IL-2 resulted in a striking enrichment of Foxp3+ T cells. These RA in vitro-induced regulatory T (RA-iTreg) cells did not secrete Th1-, Th2-, or Th17-related cytokines, showed a nonbiased homing potential, and expressed several cell surface molecules related to Treg-cell suppressive potential. Accordingly, these RA-iTreg cells suppressed T-cell proliferation and inhibited cytokine production by T cells in in vitro assays. Moreover, following adoptive transfer, RA-iTreg cells maintained Foxp3 expression and their suppressive capacity. Finally, RA-iTreg cells showed alloantigen-specific immunosuppressive capacity in a skin allograft model in immunodeficient mice. Altogether, these data indicate that functional and stable allogeneic-specific Treg cells may be generated using TGF-β, RA, and IL-2. Thus, RA-iTreg cells may have a potential use in the development of more effective cellular therapies in clinical transplantation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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    T helper type 17 cells contribute to anti-tumour immunity and promote the recruitment of T helper type 1 cells to the tumour
    (2013) Nuñez, Sarah; Saez, Juan Jose; Fernandez, Dominique; Flores-Santibañez, Felipe; Alvarez, Karla; Tejon, Gabriela; Ruiz, Paulina; Maldonado, Paula; Hidalgo, Yessia; Manriquez, Valeria; Bono, Maria Rosa; Rosemblatt, Mario; Sauma, Daniela
    T helper type 17 (Th17) lymphocytes are found in high frequency in tumour-burdened animals and cancer patients. These lymphocytes, characterized by the production of interleukin-17 and other pro-inflammatory cytokines, have a well-defined role in the development of inflammatory and autoimmune pathologies; however, their function in tumour immunity is less clear. We explored possible opposing anti-tumour and tumour-promoting functions of Th17 cells by evaluating tumour growth and the ability to promote tumour infiltration of myeloid-derived suppressor cells (MDSC), regulatory T cells and CD4+ interferon-γ+ cells in a retinoic acid-like orphan receptor γt (RORγt) -deficient mouse model. A reduced percentage of Th17 cells in the tumour microenvironment in RORγt-deficient mice led to enhanced tumour growth, that could be reverted by adoptive transfer of Th17 cells. Differences in tumour growth were not associated with changes in the accumulation or suppressive function of MDSC and regulatory T cells but were related to a decrease in the proportion of CD4+ T cells in the tumour. Our results suggest that Th17 cells do not affect the recruitment of immunosuppressive populations but favour the recruitment of effector Th1 cells to the tumour, thereby promoting anti-tumour responses. © 2012 Blackwell Publishing Ltd.