搜索结果: 'gmp t cell activator'

Extracellular cold-inducible RNA-binding protein (CIRP) exaggerates inflammation and tissue injury in sepsis. Neutrophil extracellular traps (NETs) are released by activated neutrophils during sepsis. NETs contribute to pathogen clearance,but excessive NET formation (NETosis) causes inflammation and tissue damage. Peptidylarginine deiminase 4 (PAD4) is associated with NETosis by increasing histone citrullination and chromatin decondensation. We hypothesized that CIRP induces NETosis in the lungs during sepsis via upregulating PAD4 expression. Sepsis was induced in C57BL/6 wild-type (WT) and CIRP-/- mice by cecal ligation and puncture (CLP). After 20 h of CLP induction,NETs in the lungs of WT and CIRP-/- mice were quantified by flow cytometry by staining the single cell suspensions with MPO and CitH3 Abs. PAD4 expression in the lungs of WT and CIRP-/- mice after sepsis was assessed by Western blotting. In vitro effects of recombinant mouse (rm) CIRP for NETosis and PAD4 expression in the bone marrow-derived neutrophils (BMDN) were assessed by flow cytometry and Western blotting,respectively. After 20 h of CLP,NETosis in the lungs was significantly decreased in CIRP-/- mice compared to WT mice,which also correlated with the decreased PAD4 expression. Intratracheal administration of rmCIRP into WT mice significantly increased NETosis and PAD4 expression in the lungs compared to vehicle-injected mice. In vitro culture of BMDN with rmCIRP significantly increased NETosis and PAD4 expression compared to PBS-treated control. Fluorescence microscopy revealed typical web-like structures consistent with NETs in rmCIRP-treated BMDN. Thus,CIRP serves as a novel inducer of NETosis via PAD4 during sepsis. View Publication

A novel subset of human regulatory B-cells has recently been described. They arise from within the transitional B-cell subpopulation and are characterised by the production of IL-10. They appear to be of significant importance in regulating T-cell immunity in vivo. Despite this important function,the molecular mechanisms by which they control T-cell activation are incompletely defined. Here we show that transitional B-cells produced more IL-10 and expressed higher levels of IL-10 receptor after CD40 engagement compared to other B-cell subsets. Furthermore,under this stimulatory condition,CD86 expressed by transitional B-cells was down regulated and T-cell proliferation was reduced. We provide evidence to demonstrate that the down-regulation of CD86 expression by transitional B-cells was due to the autocrine effect of IL-10,which in turn leads to decreased T-cell proliferation and TNF-α production. This analysis was further extended to peripheral B-cells in kidney transplant recipients. We observed that B-cells from patients tolerant to the graft maintained higher IL-10 production after CD40 ligation,which correlates with lower CD86 expression compared to patients with chronic rejection. Hence,the results obtained in this study shed light on a new alternative mechanism by which transitional B-cells inhibit T-cell proliferation and cytokine production. View Publication

Hypoxia-inducible transcription factors (HIFs) regulate a wide array of adaptive responses to hypoxia and are often activated in solid tumors and hematologic malignancies due to intratumoral hypoxia and emerging new layers of regulation. We found that in chronic lymphocytic leukemia (CLL),HIF-1α is a novel regulator of the interaction of CLL cells with protective leukemia microenvironments and,in turn,is regulated by this interaction in a positive feedback loop that promotes leukemia survival and propagation. Through unbiased microarray analysis,we found that in CLL cells,HIF-1α regulates the expression of important chemokine receptors and cell adhesion molecules that control the interaction of leukemic cells with bone marrow and spleen microenvironments. Inactivation of HIF-1α impairs chemotaxis and cell adhesion to stroma,reduces bone marrow and spleen colonization in xenograft and allograft CLL mouse models,and prolongs survival in mice. Of interest,we found that in CLL cells,HIF-1α is transcriptionally regulated after coculture with stromal cells. Furthermore,HIF-1α messenger RNA levels vary significantly within CLL patients and correlate with the expression of HIF-1α target genes,including CXCR4,thus further emphasizing the relevance of HIF-1α expression to CLL pathogenesis. View Publication

Recent advances in immunometabolism link metabolic changes in stimulated macrophages to production of IL-1β,a crucial cytokine in the innate immune response to Mycobacterium tuberculosis. To investigate this pathway in the host response to M. tuberculosis,we performed metabolic and functional studies on human alveolar macrophages,human monocyte-derived macrophages,and murine bone marrow-derived macrophages following infection with the bacillus in vitro. M. tuberculosis infection induced a shift from oxidative phosphorylation to aerobic glycolysis in macrophages. Inhibition of this shift resulted in decreased levels of proinflammatory IL-1β and decreased transcription of PTGS2,increased levels of anti-inflammatory IL-10,and increased intracellular bacillary survival. Blockade or absence of IL-1R negated the impact of aerobic glycolysis on intracellular bacillary survival,demonstrating that infection-induced glycolysis limits M. tuberculosis survival in macrophages through induction of IL-1β. Drugs that manipulate host metabolism may be exploited as adjuvants for future therapeutic and vaccination strategies. View Publication

Multiple sclerosis (MS) is caused by T cells that are reactive for brain antigens. In experimental autoimmune encephalomyelitis,the animal model for MS,myelin-reactive T cells initiate the autoimmune process when entering the nervous tissue and become reactivated upon local encounter of their cognate CNS antigen. Thereby,the strength of the T-cellular reactivation process within the CNS tissue is crucial for the manifestation and the severity of the clinical disease. Recently,B cells were found to participate in the pathogenesis of CNS autoimmunity,with several diverse underlying mechanisms being under discussion. We here report that B cells play an important role in promoting the initiation process of CNS autoimmunity. Myelin-specific antibodies produced by autoreactive B cells after activation in the periphery diffused into the CNS together with the first invading pathogenic T cells. The antibodies accumulated in resident antigen-presenting phagocytes and significantly enhanced the activation of the incoming effector T cells. The ensuing strong blood-brain barrier disruption and immune cell recruitment resulted in rapid manifestation of clinical disease. Therefore,myelin oligodendrocyte glycoprotein (MOG)-specific autoantibodies can initiate disease bouts by cooperating with the autoreactive T cells in helping them to recognize their autoantigen and become efficiently reactivated within the immune-deprived nervous tissue. View Publication

Acute myeloid leukemia (AML) is the most common type of acute leukemia affecting older individuals at a median age of 67 years. Resistance to intensive induction chemotherapy is the major cause of death in elderly AML; hence novel treatment strategies are warranted. CD33-directed antibody-drug conjugates (Gemtuzumab ozogamicin) have been shown to improve overall survival,validating CD33 as a target for antibody-based therapy of AML. Here we report the in vitro efficacy of BI 836858,a fully human,Fc-engineered,anti-CD33 antibody using AML cell lines and primary AML blasts as targets. BI 836858-opsonized AML cells significantly induced both autologous and allogeneic natural killer (NK)-cell degranulation and NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC). In vitro treatment of AML blasts with decitabine (DAC) or 5-azacytidine,two hypomethylating agents that show efficacy in older patients,did not compromise BI 836858-induced NK cell-mediated ADCC. Evaluation of BI 836858-mediated ADCC in serial marrow AML aspirates in patients who received a ten-day course of DAC (pre-DAC,days 4,11 and 28 post-DAC) revealed significantly higher ADCC in samples at day 28 post-DAC when compared to pre-DAC treatment. Analysis of ligands (L) to activating receptors (NKG2D showed significantly increased NKG2DL expression in day 28 post-DAC samples compared to pre-DAC samples; when NKG2DL receptor was blocked using antibodies,BI 836858-mediated ADCC was significantly decreased,suggesting that DAC enhances AML blast susceptibility to BI 836858 by upregulating NKG2DL. These data provide a rationale for combination therapy of Fc-engineered antibodies such as BI 836858 with azanucleosides in elderly patients with AML. View Publication

We examined the role of NFκB1 in the homeostasis and function of peripheral follicular (Fo) B cells. Aging mice lacking NFκB1 (Nfκb1(-/-)) develop lymphoproliferative and multiorgan autoimmune disease attributed in large part to the deregulated activity ofNfκb1(-/-)Fo B cells that produce excessive levels of the proinflammatory cytokine interleukin 6 (IL-6). Despite enhanced germinal center (GC) B cell differentiation,the formation of GC structures was severely disrupted in theNfκb1(-/-)mice. Bone marrow chimeric mice revealed that the Fo B cell-intrinsic loss of NFκB1 led to the spontaneous generation of GC B cells. This was primarily the result of an increase in IL-6 levels,which promotes the differentiation of Fo helper CD4(+)T cells and acts in an autocrine manner to reduce antigen receptor and toll-like receptor activation thresholds in a population of proliferating IgM(+)Nfκb1(-/-)Fo B cells. We demonstrate that p50-NFκB1 repressesIl-6transcription in Fo B cells,with the loss of NFκB1 also resulting in the uncontrolled RELA-driven transcription ofIl-6.Collectively,our findings identify a previously unrecognized role for NFκB1 in preventing multiorgan autoimmunity through its negative regulation ofIl-6gene expression in Fo B cells. View Publication

B cell activation and Ab production in response to protein Ags requires presentation of peptides for recruitment of T cell help. We and others have recently demonstrated that B cells can also acquire innate help by presenting lipid Ags via CD1d to NKT cells. Given the newfound contribution of NKT cells to humoral immunity,we sought to identify the pathways that regulate CD1 molecule expression in human B cells. We show that ex vivo,activated and memory B cells expressed lower levels of CD1d compared with resting,naive,and marginal zone-like B cells. In vitro,CD1d was downregulated by all forms of B cell activation,leaving a narrow temporal window in which B cells could activate NKT cells. CD1c expression and function also decreased following activation by CD40L alone,whereas activation via the BCR significantly upregulated CD1c,particularly on marginal zone-like B cells. We found that the CD40L-induced downregulation of CD1d and CD1c correlated with diminished expression of retinoic acid receptor α (RARα) response genes,an effect that was reversed by RARα agonists. However,BCR-induced upregulation of CD1c was independent of the RAR pathway. Our findings that both CD1d and CD1c are upregulated by RARα signaling in human B cells is distinct from effects reported in dendritic cells,in which CD1c is inversely downregulated. One functional consequence of CD1d upregulation by retinoic acid was NKT cell cytotoxicity toward B cells. These results are central to our understanding of how CD1-restricted T cells may control humoral immunity. View Publication

Most forms of chemotherapy employ mechanisms involving induction of oxidative stress,a strategy that can be effective due to the elevated oxidative state commonly observed in cancer cells. However,recent studies have shown that relative redox levels in primary tumors can be heterogeneous,suggesting that regimens dependent on differential oxidative state may not be uniformly effective. To investigate this issue in hematological malignancies,we evaluated mechanisms controlling oxidative state in primary specimens derived from acute myelogenous leukemia (AML) patients. Our studies demonstrate three striking findings. First,the majority of functionally defined leukemia stem cells (LSCs) are characterized by relatively low levels of reactive oxygen species (termed ROS-low"). Second� View Publication

Neural stem cells (NSCs) possess immunosuppressive characteristics,but effects of NSCs on human dendritic cells (DCs),the most important antigen presenting cells,are less well studied. We used an in vitro approach to evaluate the effects of human NSCs on differentiation of human blood CD14+ monocytes into DCs. NSCs derived from H1 human embryonic stem cells (hESC-NSCs) and human ReNcell NSC line,as well as human bone marrow derived mesenchymal stem cells (MSCs),were tested. We observed that in response to treatment with interleukin-4 and granulocyte macrophage colony-stimulating factor CD14+ monocytes co-cultured with NSCs were able to down-regulate CD14 and up-regulate the differentiation marker CD1a,whereas MSC co-culture strongly inhibited CD1a expression and supported prolonged expression of CD14. A similar difference between NSCs and MSCs was noted when lipopolysaccharides were included to induce maturation of monocyte-derived DCs. However,when effects on the function of derived DCs were investigated,NSCs suppressed the elevation of the DC maturation marker CD83,although not the up-regulation of costimulatory molecules CD80,CD86 and CD40,and impaired the functional capacity of the derived DCs to stimulate alloreactive T cells. We did not observe any obvious difference between hESC-NSCs and ReNcell NSCs in inhibiting DC maturation and function. Our data suggest that although human NSCs are less effective than human MSCs in suppressing monocyte differentiation into DCs,these stem cells can still affect the function of DCs,ultimately regulating specific immune responses. View Publication