Kinetics of pDCs, mDCs, γδT cells and regulatory T cells in association with graft versus host disease after hematopoietic stem cell transplantation

Introduction: Although the roles of each low‐frequency immunocompetent cells such as dendritic cells (DCs), γδT cells, and Treg cells in induction of acute or chronic graft versus host disease (GVHD) have been discussed in several reports, there are few papers dealing with an evaluation of these immunocompetent cells together and simultaneously in patients with hematopoietic stem cell transplantation (HSCT) and explored the kinetics of these cells in association with GVHD. Methods: In the present study, we assessed the number of plasmacytoid DCs (pDCs), myeloid DCs (mDCs), γδT cells and Treg cells serially in patients who received allogeneic HSCT and analyzed the relationship of these cells with acute or chronic GVHD (cGVHD) by using flow cytometry. Results: The percentages and numbers of pDCs, mDC1s and γδT cells were significantly lowered in the patients with acute GVHD (aGVHD) compared with those with no GVHD. On the contrary, the percentages and numbers of Treg cells were significantly elevated in the patients with aGVHD compared with those with no GVHD. As to the association with cGVHD, Treg cells were elevated in the patients with cGVHD, compared with those with no GVHD. Conclusion: The present study revealed an association of pDCs, mDCs, γδT cells and Treg cells with induction or treatment of GVHD.     

Characterization of CD4 and CD8 T cells producing IFN-γ in human latent and active tuberculosis

Patients with pulmonary tuberculosis (PTB) frequently have reduced IFN-γ production in response to mycobacterial antigens, compared to individuals with latent Mycobacterium tuberculosis infection (LTBi). However, it is not clear whether this reduced responsiveness is restricted to a particular T cell subset. Herein, PBMCs from 26 PTB patients, 30 household contacts (HHCs) of PTB, and 30 tuberculin positive (TST+) healthy subjects not recently exposed to PTB, were stained with CFSE and stimulated non-specific (PPD) for 120?h, and specific (CFP-10/ESAT-6) and latency (HSpX) mycobacterial antigens for 144?h and the percentage of CD4(+) and CD8(+)IFN-γ(+) T cells responding determined by flow cytometry, in addition to their memory phenotype by the CD45RO and CD27 expression. PTB had decreased frequency of both CD4(+) and CD8(+) precursor cells, as well as decreased number of CD4(+)IFN-γ(+) cells in response to all antigens, whereas CD8(+)IFN-γ(+) cells were decreased in response to PPD and ESAT-6, but not to CFP-10 and HSpX. HHCs exhibited the highest precursor frequencies and IFN-γ responses, irrespective of the antigen employed. The CD4(+)/CD8(+) cell ratios showed that in response to PPD CD4(+) precursor and IFN-γ-producer cells are more frequent than their CD8(+) counterparts, and that PTB have a decreased CD4(+)IFN-γ(+)/CD8(+)IFN-γ(+) ratio in response to PPD, CFP-10, and ESAT-6. CD4(+)IFN-γ(+) and CD8(+)IFN-γ(+) cells exhibited a central memory phenotype (CD45RO(+)CD27(+)), irrespective of the group of subjects and the antigen used for stimulation. In conclusion, PTB patients had a decreased percentage of CD4(+) and CD8(+) precursor cells and CD4(+)IFN-γ(+). HHCs exhibited the highest frequency of CD4(+) and CD8(+) precursors and CD4(+)IFN-γ(+)-producing cells.     

Chlamydia muridarum respiratory tract infection induces the proliferation of γδT cells and the secretion of IFN-γ and IL-17

<正>Objective To investigate the proliferation,activation and cytokine production ofγδT cells during different periods of Chlamydia muridarum(Cm)respiratory tract infection.Methods C57BL/6 mice were inoculated intranasally with 3×103inclusion-forming units(IFU)of Cm strains to induce the murine model of chlamydial     

Identification of an IL-27/osteopontin axis in dendritic cells and its modulation by IFN-γ limits IL-17–mediated autoimmune inflammation

Dendritic cells (DCs) play a central role in determining the induction of T cell responses. IL-27 production by DCs favors induction of IL-10–producing regulatory T cells, whereas osteopontin (OPN) promotes pathogenic IL-17 T cell responses. The regulatory mechanisms in DCs that control these two cells types are not understood well. Here, we show that IFN-γ induces IL-27 while inhibiting OPN expression in DCs both in vitro and in vivo and that engagement of IFN-γR expressed by DCs leads to suppression of IL-17 production while inducing IL-10 from T cells. DCs modified by IFN-γ acquire IL-27–dependent regulatory function, promote IL-10–mediated T cell tolerance, and suppress autoimmune inflammation. Thus, our results identify a previously unknown pathway by which IFN-γ limits IL-17–mediated autoimmune inflammation through differential regulation of OPN and IL-27 expression in DCs.IL-27 is a potent antiinflammatory cytokine, which belongs to the IL-12 family and is comprised of an IL-12p40–related protein, encoded by the EBV-induced gene 3 (EBI3, also known as IL27), and a unique IL-12p35–like protein, IL-27p28v (1). Initial animal studies on the biology of IL-27 suggested a role for IL-27 in the initiation of the Th1 response (2, 3); however, subsequent work using mouse models of pathogen-induced and autoimmune inflammation have indicated that IL-27 has broad inhibitory effects on Th1, Th2 subsets of T cells and APC function in mice (4, 5). In addition, we and others have shown that IL-27 is capable of inducing IL-10–producing regulatory Tr1 cells while inhibiting IL-17–producing Th17 cells both from humans and mice and acts as a negative feedback mechanism against proinflammatory immune responses (6–10).Contrary to the function of IL-27, osteopontin (OPN) is known to have potent proinflammatory functions. OPN participates in a wide range of biological processes (11) and has been linked to autoimmune diseases including multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). Mice deficient for OPN (Spp1^−/−, also known as OPN^−/−) show milder EAE without disease exacerbation or progression compared with WT mice (12, 13). Patients with MS have elevated levels of OPN in their serum and plasma (14, 15). OPN exacerbates EAE by skewing T cell differentiation toward IFN-γ–producing Th1 cells and IL-17–producing Th17 cells (12, 13, 16–18). In addition, OPN induces IFN-γ– and IL-17–producing T cells in patients with MS (16).Dendritic cells (DCs) are crucial in the initiation of productive antigen-specific T cell responses and the induction of T cell tolerance (19, 20). This dual function was initially explained by the existence of specific subpopulations of DCs that preferentially trigger T cell priming, whereas other subpopulations were identified to induce T cell tolerance (21–23). The demonstration that a single DC subpopulation can elicit both T cell outcomes, led to an alternative explanation that the functional status of the DC at the time of antigen presentation, rather than its phenotypic characteristics, is critical for determining T cell responses (24). Among the factors linked to the functional status of DCs, the types of cytokines secreted by DCs can regulate the differentiation of CD4⁺ T cells into functional subsets including IL-17–producing pathogenic Th17 cells and IL-10–producing regulatory Tr1 cells. For example, IL-10 or IL-27 production by DCs favors generation of IL-10–producing Tr1 cells (6, 25), whereas OPN production by DCs promotes IL-17–producing Th17 cells (16, 17). However, it is unknown how IL-27 and OPN expression in DCs are modulated to regulate both IL-10 and IL-17 production by T cells.Here, we show that IFN-γ induces IL-27 while inhibiting OPN expression in DCs both in vitro and in vivo. IFN-γ^−/−-deficient mice in which EAE is induced have increased serum OPN and lower IL-27 levels in comparison with WT mice. Engagement of IFNγR expressed by DCs leads to suppression of IL-17 production and induction of IL-10 from T cells. Furthermore, IFN-γ–modified DCs ameliorate the disease severity of EAE through an IL-27–dependent mechanism. Taken together, our results identify a previously unknown pathway by which IFN-γ limits IL-17–mediated autoimmune inflammation through reciprocal DC modulation of OPN and IL-27.     

Unique roles of Schistosoma japonicum protein Sj16 to induce IFN-γ and IL-10 producing CD4(+) CD25(+) regulatory T cells in vitro and in vivo

Various proteins are expressed during different stages of schistosome development that are essential for cercarial penetration of vertebrate skin and evasion of host immune response. CD4(+) CD25(+) regulatory T cells are important in modulating immune responses towards helminth infections. Schistosoma japonicum protein Sj16 present in the secretions of schistosomula has been shown to have anti-inflammatory effects; however, it is uncertain whether Sj16 can induce CD4(+) CD25(+) regulatory T cells to participate in the regulation of early infection. In this study, we demonstrate a relationship between recombinant Sj16 (rSj16) and the induction of CD4(+) CD25(+) Foxp3(+) regulatory T cells. An increase in CD4(+) CD25(+) T cells was observed both in splenic cells from mice injected with rSj16 and the cells pretreated with rSj16, respectively. The induced CD4(+) CD25(+) T cells suppressed CD4(+) CD25(-) T-cell proliferation; furthermore, IFN-γ and IL-10 released from rSj16-stimulated cells contribute to this suppression. Additionally, rSj16-treated bone marrow dendritic cells (BMDCs) demonstrate an immature phenotype and play a role in the conversion of CD4(+) CD25(-) T cells into suppressive CD4(+) CD25(+) regulatory T cells. Our study identified a new CD4(+) CD25(+) T-cell population that induced by rSj16 and suggests that an IFN-γ-biased microenvironment during early infection of schistosome may favour the establishment of infection.