107 research outputs found

    CD25+ immunoregulatory T-cells of donor origin suppress alloreactivity after BMT

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    AbstractWe have previously identified donor-derived Thy1+ alphabeta T-cell receptor (TCR)+ CD4+ CD8- regulatory T-cells that suppress GVH reactivity induced by donor leukocyte infusion (DLI) after BMT. These cells develop in the recipient thymus and may play a role in the maintenance of donor-host tolerance after allogeneic BMT. In the present study, we sought to further characterize the T-cells responsible for the regulatory cell activity in our model. Lethally irradiated recipient AKR mice (H-2k) received transplants of BM from CD25-deficient (-/-) C57BL/6 mice (H-2b). Recipients of CD25-deficient BM developed more severe GVHD after DLI than did recipients of normal BM, a result that indirectly suggests that CD4+ CD25+ regulatory T-cells are important to the suppression of GVH reactivity after allogeneic BMT. GVHD was accompanied by mortality, body weight loss, and elevated percentages of T-cells from the DLI in the peripheral blood in mice that received CD25-deficient BM compared to mice that received normal BM. Both CD40-CD40L and CD28-B7 costimulatory pathways have been implicated in the generation of CD25+ regulatory T-cells. Therefore, we tested whether deficiency in either of these pathways affected the activity of donor BM-derived regulatory T-cells. The absence of CD40L did not affect the regulatory T-cells (ie, recipient mice were still protected from DLI-induced GVHD). In contrast, use of marrow from CD28-deficient mice resulted in complete loss of suppression of GVH reactivity. Thus, CD28 but not CD40L was critical for the generation and/or activation of immunoregulatory T-cells that suppressed GVHD induced by DLI. Together, the results of these experiments suggest that CD4+ CD25+ regulatory T-cells suppress GVH reactivity after BMT and that CD28 expression is indispensable for the generation of these cells.Biol Blood Marrow Transplant 2002;8(10):525-35

    Multi Targeted CAR-T Cell Therapies for B-Cell Malignancies

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    Chimeric antigen receptor (CAR) modified T cell therapy has revolutionized the treatment of relapsed and refractory hematological malignancies. Through targeting of the CD19 antigen on B cells durable remissions have been achieved in patients with B cell non-Hodgkin lymphoma and acute lymphoblastic lymphoma. Despite impressive responses, multiple escape mechanisms to evade CAR-T cell therapy have been identified, among which the most common is loss of the target antigen. In this review we will highlight outcomes to date with CD19 CAR-T cell therapy, describe the current limitations of single targeted CAR-T therapies, review identified tumor escape mechanisms, and lastly discuss novel strategies to overcome resistance via multi-targeted CAR-T cells

    Elucidating the role of ferrous ion cocatalyst in enhancing dilute acid pretreatment of lignocellulosic biomass

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    <p>Abstract</p> <p>Background</p> <p>Recently developed iron cocatalyst enhancement of dilute acid pretreatment of biomass is a promising approach for enhancing sugar release from recalcitrant lignocellulosic biomass. However, very little is known about the underlying mechanisms of this enhancement. In the current study, our aim was to identify several essential factors that contribute to ferrous ion-enhanced efficiency during dilute acid pretreatment of biomass and to initiate the investigation of the mechanisms that result in this enhancement.</p> <p>Results</p> <p>During dilute acid and ferrous ion cocatalyst pretreatments, we observed concomitant increases in solubilized sugars in the hydrolysate and reducing sugars in the (insoluble) biomass residues. We also observed enhancements in sugar release during subsequent enzymatic saccharification of iron cocatalyst-pretreated biomass. Fourier transform Raman spectroscopy showed that major peaks representing the C-O-C and C-H bonds in cellulose are significantly attenuated by iron cocatalyst pretreatment. Imaging using Prussian blue staining indicated that Fe<sup>2+ </sup>ions associate with both cellulose/xylan and lignin in untreated as well as dilute acid/Fe<sup>2+ </sup>ion-pretreated corn stover samples. Analyses by scanning electron microscopy and transmission electron microscopy revealed structural details of biomass after dilute acid/Fe<sup>2+ </sup>ion pretreatment, in which delamination and fibrillation of the cell wall were observed.</p> <p>Conclusions</p> <p>By using this multimodal approach, we have revealed that (1) acid-ferrous ion-assisted pretreatment increases solubilization and enzymatic digestion of both cellulose and xylan to monomers and (2) this pretreatment likely targets multiple chemistries in plant cell wall polymer networks, including those represented by the C-O-C and C-H bonds in cellulose.</p

    Cancer chemoprevention with PV-1, a novel Prunella vulgaris-containing herbal mixture that remodels the tumor immune microenvironment in mice

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    The herb Prunella vulgaris has shown significant immune-stimulatory and anti-inflammatory effects in mouse models. Here, the effects of a novel Prunella vulgaris-containing herbal mixture, PV-1, were examined in several mouse models for cancer, including chemically induced models of lung and oral cancers as well as syngraft models for lung cancer and melanoma. PV-1, consisting of extracts from Prunella vulgaris, Polygonum bistorta, Sonchus brachyotus and Dictamnus dasycarpus, exhibited no toxicity in a dose escalation study in A/J mice. PV-1 significantly inhibited mouse lung tumor development induced by the lung carcinogens vinyl carbamate and benzo[a]pyrene. PV-1 also hindered the induction of oral squamous cell carcinomas in C57BL/6 mice caused by 4-nitroquinoline-1-oxide. Flow cytometry analysis showed that PV-1 increased the numbers of CD8+ tumor-infiltrating lymphocytes (TILs) and increased the production of granzyme B, TNF-α, and IFN-γ by CD8+ TILs. PV-1 also suppressed granulocytic myeloid-derived suppressor cell numbers (g-MDSCs) and improved the anti‐cancer activity of anti-PD‐1 immunotherapy. These results indicate that PV-1 remodels the tumor immune microenvironment by selectively inhibiting g‐MDSCs and increasing CD8+ TILs within tumors, resulting in decreased immune suppression and enhanced cancer chemopreventive efficacy

    Immune response modulation by curcumin in a latex allergy model

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    BACKGROUND: There has been a worldwide increase in allergy and asthma over the last few decades, particularly in industrially developed nations. This resulted in a renewed interest to understand the pathogenesis of allergy in recent years. The progress made in the pathogenesis of allergic disease has led to the exploration of novel alternative therapies, which include herbal medicines as well. Curcumin, present in turmeric, a frequently used spice in Asia has been shown to have anti-allergic and inflammatory potential. METHODS: We used a murine model of latex allergy to investigate the role of curcumin as an immunomodulator. BALB/c mice were exposed to latex allergens and developed latex allergy with a Th2 type of immune response. These animals were treated with curcumin and the immunological and inflammatory responses were evaluated. RESULTS: Animals exposed to latex showed enhanced serum IgE, latex specific IgG(1), IL-4, IL-5, IL-13, eosinophils and inflammation in the lungs. Intragastric treatment of latex-sensitized mice with curcumin demonstrated a diminished Th2 response with a concurrent reduction in lung inflammation. Eosinophilia in curcumin-treated mice was markedly reduced, co-stimulatory molecule expression (CD80, CD86, and OX40L) on antigen-presenting cells was decreased, and expression of MMP-9, OAT, and TSLP genes was also attenuated. CONCLUSION: These results suggest that curcumin has potential therapeutic value for controlling allergic responses resulting from exposure to allergens
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