Person: Gao, W
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Publication Exogenous IFN-γ Ex Vivo Shapes the Alloreactive T-Cell Repertoire by Inhibition of Th17 Responses and Generation of Functional Foxp3+ Regulatory T Cells(WILEY-VCH Verlag, 2008) Feng, Gang; Gao, W; Strom, Terry B.; Oukka, Mohamed; Francis, Ross S; Wood, Kathryn J; Bushell, AndrewInterferon (IFN)-γ was originally characterized as a pro-inflammatory cytokine with T helper type 1-inducing activity, but subsequent work has demonstrated that mice deficient in IFN-γ or IFN-γ receptor show exacerbated inflammatory responses and accelerated allograft rejection, suggesting that IFN-γ also has important immunoregulatory functions. Here, we demonstrate that ex vivo IFN-γ conditioning of CD4 T cells driven by allogeneic immature dendritic cells (DC) results in the emergence of a Foxp3+ regulatory T-cell (Treg)- dominant population that can prevent allograft rejection. The development of this population involves conversion of non-Treg precursors, preferential induction of activation-induced cell death within the non-Treg population and suppression of Th2 and Th17 responses. The suppressive activity of IFN-γ is dependent on the transcription factor signal transducer and activator of transcription 1 and is mediated by induced nitric oxide. These data indicate not only how IFN-γ could be used to shape beneficial immune responses ex vivo for possible cell therapy but also provide some mechanistic insights that may be relevant to exacerbated inflammatory responses noted in several autoimmune and transplant models with IFN-γ deficiency.Publication Human CD4+ Memory T Cells Can Become CD4+IL-9+ T Cells(Public Library of Science, 2010) Putheti, P; Awasthi, Amit; Popoola, Joyce; Gao, W; Strom, Terry B.Background: IL-9 is a growth factor for T- and mast-cells that is secreted by human Th2 cells. We recently reported that IL-4+TGF-β directs mouse CD4+CD25−CD62L+ T cells to commit to inflammatory IL-9 producing CD4+ T cells. Methodology/Principal Findings: Here we show that human inducible regulatory T cells (iTregs) also express IL-9. IL-4+TGF-β induced higher levels of IL-9 expression in plate bound-anti-CD3 mAb (pbCD3)/soluble-anti-CD28 mAb (sCD28) activated human resting memory CD4+CD25−CD45RO+ T cells as compared to naïve CD4+CD25−CD45RA+ T cells. In addition, as compared to pbCD3/sCD28 plus TGF-β stimulation, IL-4+TGF-β stimulated memory CD4+CD25−CD45RO+ T cells expressed reduced FOXP3 protein. As analyzed by pre-amplification boosted single-cell real-time PCR, human CD4+IL-9+ T cells expressed GATA3 and RORC, but not IL-10, IL-13, IFNγ or IL-17A/F. Attempts to optimize IL-9 production by pbCD3/sCD28 and IL-4+TGF-β stimulated resting memory CD4+ T cells demonstrated that the addition of IL-1β, IL-12, and IL-21 further enhance IL-9 production. Conclusions/Significance: Taken together these data show both the differences and similarities between mouse and human CD4+IL9+ T cells and reaffirm the powerful influence of inflammatory cytokines to shape the response of activated CD4+ T cells to antigen.