bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Recombinant Fusion Protein Encoding a 20-Amino Acid Residue of the Third Extracellular (E3) Domain of CCR2 Neutralizes the Biological Activity of CCL2
Authors: Izhak Liat , Wildbaum Gizi , Zohar Yaniv , Anunu Rachel , Klapper Leah , Elkeles Adi , Seagal Jane , Yefenof Eitan , Ayalon-Soffer Michal , Karin Nathan 
Published: June 2009

Abstract
CCL2 is a key CC chemokine that has been implicated in a variety of inflammatory autoimmune diseases and in tumor progression and it is therefore an important target for therapeutic intervention in these diseases. Soluble receptor-based therapy is a known approach for neutralizing the in vivo functions of soluble mediators. Owing to the complexity of seven-transmembrane G protein-coupled receptors, efforts to generate neutralizing soluble chemokine receptors have so far failed. We developed a strategy that is based on the generation of short recombinant proteins encoding different segments of a G protein-coupled receptor, and tested the ability of each of them to bind and neutralize its target chemokine. We show that a fusion protein comprised of as few as 20 aa of the third extracellular (E3) domain of the CCL2 receptor, stabilized by the IgG H chain Fc domain (E3-IgG or BL-2030), selectively binds CCL2 and CCL16 and effectively neutralizes their biological activities. More importantly, E3-IgG (BL-2030) could effectively suppress the in vivo biological activity of CCL2, attenuating ongoing experimental autoimmune encephalomyelitis, as well as the development of human prostate tumor in SCID mice.
Tryptophan Deprivation Induces Inhibitory Receptors ILT3 and ILT4 on Dendritic Cells Favoring the Induction of Human CD4+CD25+ Foxp3+ T Regulatory Cells
Authors: Brenk Manuela , Scheler Marina , Koch Susanne , Neumann Jürgen , Takikawa Osamu , Häcker Georg , Bieber Thomas , von Bubnoff Dagmar 
Published: June 2009

Abstract
Tryptophan catabolism through IDO activity can cause nonresponsiveness and tolerance acting on T cells. Given the crucial importance of dendritic cells (DCs) in the initiation of a T cell response, surprisingly little is known about the impact of IDO activity and tryptophan deprivation on DCs themselves. In the present study, we show that human DCs differentiated under low-tryptophan conditions acquire strong tolerogenic capacity. This effect is associated with a markedly decreased Ag uptake as well as the down-regulation of costimulatory molecules (CD40, CD80). In contrast, the inhibitory receptors ILT3 and ILT4 are significantly increased. Functionally, tryptophan-deprived DCs show a reduced capacity to stimulate T cells, which can be restored by blockade of ILT3. Moreover, ILT3highILT4high DCs lead to the induction of CD4+CD25+ Foxp3+ T regulatory cells with suppressive activity from CD4+CD25− T cells. The generation of ILT3highILT4high DCs with tolerogenic properties by tryptophan deprivation is linked to a stress response pathway mediated by the GCN2 kinase. These results demonstrate that tryptophan degradation establishes a regulatory microenvironment for DCs, enabling these cells to induce T regulatory cells. The impact of IDO thus extends beyond local immune suppression to a systemic control of the immune response.
CD44high Memory CD8 T Cells Synergize with CpG DNA to Activate Dendritic Cell IL-12p70 Production
Authors: Wong Kok Loon , Tang Li Fang Melissa , Lew Fei Chuin , Wong Hok Sum Kenneth , Chua Yen Leong , MacAry Paul A. , Kemeny David M. 
Published: June 2009

Abstract
Protective memory CD8 T cell responses are generally associated with the rapid and efficient acquisition of CTL function. However, the ability of memory CD8 T cells to modulate immune responses through interactions with dendritic cells (DCs) during the early states of secondary Ag exposure is poorly understood. In this study, we show that murine Ag-specific CD44high CD8 T cells, representing CD8 T cells of the memory phenotype, potently activate DCs to produce high levels of IL-12p70 in conjunction with stimulation of DCs with the TLR 9 ligand, unmethylated CpG DNA. IL-12p70 production was produced predominantly by CD8α+ DCs and plasmacytoid DCs, and mediated by CD8 T cell-derived cytokines IFN-γ, GM-CSF, TNF-α, and surface CD40L. We also find that CD44high memory phenotype CD8 T cells were better DC IL-12p70 stimulators than CD44low naive phenotype CD8 T cells, and this was attributed to higher levels of IFN-γ and GM-CSF produced by CD44high memory phenotype CD8 T cells during their Ag specific interaction with DCs. Our study identifies CpG DNA as the most effective TLR ligand that cooperates with CD8 T cells for DC IL-12p70 production, and suggests that effectiveness of memory CD8 T cells could be attributed to their ability to rapidly and effectively induce protective Th1 immunity during early stages of pathogen reinfection.
Systemic Reduction of Functionally Suppressive CD4dimCD25highFoxp3+ Tregs in Human Second Trimester Pregnancy Is Induced by Progesterone and 17β-Estradiol
Authors: Mjösberg Jenny , Svensson Judit , Johansson Emma , Hellström Lotta , Casas Rosaura , Jenmalm Maria C. , Boij Roland , Matthiesen Leif , Jönsson Jan-Ingvar , Berg Göran , Ernerudh Jan 
Published: June 2009

Abstract
CD4+CD25high regulatory T cells (Tregs) are implicated in the maintenance of murine pregnancy. However, reports regarding circulating Treg frequencies in human pregnancy are inconsistent, and the functionality and phenotype of these cells in pregnancy have not been clarified. The aim of this study was to determine the frequency, phenotype, and function of circulating Tregs in the second trimester of human pregnancy and the influence of progesterone and 17β-estradiol on Treg phenotype and frequency. Based on expressions of Foxp3, CD127, and HLA-DR as determined by multicolor flow cytometry, we defined a proper CD4dimCD25high Treg population and showed, in contrast to most previous reports, that this population was reduced in second trimester of pregnancy. Unexpectedly, Foxp3 expression was decreased in the Treg, as well as in the CD4+ population. These changes could be replicated in an in vitro system resembling the pregnancy hormonal milieu, where 17β-estradiol, and in particular progesterone, induced, in line with the pregnancy situation, a reduction of CD4dimCD25highFoxp3+ cells in PBMC from nonpregnant women. By coculturing FACS-sorted Tregs and autologous CD4+CD25− responder cells, we showed that Tregs from pregnant women still displayed the same suppressive capacity as nonpregnant women in terms of suppressing IL-2, TNF-α, and IFN-γ secretion from responder cells while efficiently producing IL-4 and IL-10. Our findings support the view of hormones, particularly progesterone, as critical regulators of Tregs in pregnancy. Furthermore, we suggest that in the light of the results of this study, early data on circulating Treg frequencies in pregnancy need reevaluation.
STAT6 Activation Confers upon T Helper Cells Resistance to Suppression by Regulatory T Cells
Authors: Pillemer Brendan B. L. , Qi Zengbiao , Melgert Barbro , Oriss Timothy B. , Ray Prabir , Ray Anuradha 
Published: June 2009

Abstract
Recent studies have highlighted characteristics of T regulatory cells (Tregs) that underlie their suppressive function. However, mechanisms that override their suppressive function in the context of an adaptive immune response are not well understood. In the lungs of mice undergoing allergic inflammation, appreciable numbers of Tregs were identified that possessed suppressive function when assayed ex vivo. We investigated whether the Th2-promoting cytokine IL-4 played a permissive role that superseded Treg function, thereby allowing the development of allergic inflammation. IL-4 signaling via the IL-4Rα-STAT6 axis was required to maintain Foxp3 expression in Tregs and promote their proliferation. However, the results of both in vivo experiments involving adoptive transfer of Tregs into Ag-sensitized vs naive animals and in vitro suppression assays performed with or without exogenous IL-4 showed the ability of IL-4 to compromise Treg-mediated suppression. Use of retrovirally expressed, constitutively active STAT6 revealed that the underlying mechanism was not IL-4-mediated dysfunction of Tregs but involved the resistance of Th cells to Treg-mediated suppression that would permit the development of an adaptive immune response. Our data suggest that infectious tolerance, mediated by membrane-bound TGF-β expressed by Tregs, is compromised by the competing effects of IL4-induced signaling in naive CD4+ Th cells.
Restricted Autoantigen Recognition Associated with Deletional and Adaptive Regulatory Mechanisms
Authors: Gebe John A. , Yue Betty B. , Unrath Kelly A. , Falk Ben A. , Nepom Gerald T. 
Published: June 2009

Abstract
Autoimmune diabetes (T1D) is characterized by CD4+ T cell reactivity to a variety of islet-associated Ags. At-risk individuals, genetically predisposed to T1D, often have similar T cell reactivity, but nevertheless fail to progress to clinically overt disease. To study the immune tolerance and regulatory environment permissive for such autoreactive T cells, we expressed TCR transgenes derived from two autoreactive human T cells, 4.13 and 164, in HLA-DR4 transgenic mice on a C57BL/6-derived “diabetes-resistant” background. Both TCR are responsive to an immunodominant epitope of glutamic acid decarboxylase 65555–567, which is identical in sequence between humans and mice, is restricted by HLA-DR4, and is a naturally processed self Ag associated with T1D. Although both TCR use the identical Vα and Vβ genes, differing only in CDR3, we found stark differences in the mechanisms utilized in vivo in the maintenance of immune tolerance. A combination of thymic deletion (negative selection), TCR down-regulation, and peripheral activation-induced cell death dominated the phenotype of 164 T cells, which nevertheless still maintain their Ag responsiveness in the periphery. In contrast, 4.13 T cells are much less influenced by central and deletional tolerance mechanisms, and instead display a peripheral immune deviation including differentiation into IL-10-secreting Tr1 cells. These findings indicate a distinct set of regulatory alternatives for autoreactive T cells, even within a single highly restricted HLA-peptide-TCR recognition profile.
T-bet-Deficient NOD Mice Are Protected from Diabetes Due to Defects in Both T Cell and Innate Immune System Function
Authors: Esensten Jonathan H. , Lee Michael R. , Glimcher Laurie H. , Bluestone Jeffrey A. 
Published: June 2009

AbstractThe transcription factor T-bet (Tbx21) is critical for Th1 polarization of CD4+ T cells. Genetic deletion of Tbx21 can cause either exacerbation or attenuation of different autoimmune diseases in animal models. In the nonobese diabetic (NOD) mouse, genetic deletion of the Ifng or the Il12b (IL-12p40) genes, which are both critical Th1 cytokines, does not reduce the incidence of autoimmune diabetes. These results suggest that autoimmune diabetes in the NOD may not be a Th1-driven disease. However, we report that Tbx21 deficiency in the NOD mouse completely blocks insulitis and diabetes due to defects both in the initiation of the anti-islet immune response and in the function of CD4+ effector T cells. We find defective priming of naive islet-reactive T cells by the innate immune system in Tbx21−/− animals. By contrast to naive cells, activated islet-reactive BDC2.5 TCR-transgenic T cells do not require Tbx21 in recipient animals for efficient adoptive transfer of diabetes. However, when these BDC2.5 TCR-transgenic effector cells lack Tbx21, they are less effective at entering the pancreas and promoting diabetes than Tbx21+/+ cells. Tbx21−/− regulatory T cells function normally in vitro and diabetes can be restored in Tbx21−/− mice by reducing regulatory T cell numbers. Thus, the absence of diabetes in the NOD.Tbx21−/− is due to intrinsic defects in both T cells and cells of the innate immune system paired with the relative preservation of regulatory T cell function.
Expression of IL-24, an Activator of the JAK1/STAT3/SOCS3 Cascade, Is Enhanced in Inflammatory Bowel Disease
Authors: Andoh Akira , Shioya Makoto , Nishida Atsushi , Bamba Shigeki , Tsujikawa Tomoyuki , Kim-Mitsuyama Shokei , Fujiyama Yoshihide 
Published: June 2009

Abstract
IL-24 is a member of the IL-10 family of cytokines. In this study, we investigated IL-24 expression in the inflamed mucosa of patients with inflammatory bowel disease (IBD), and characterized the molecular mechanisms responsible for IL-24 expression in human colonic subepithelial myofibroblasts (SEMFs). IL-24 expression in the IBD mucosa was evaluated by immunohistochemical methods. IL-24 mRNA and protein expression was determined by real-time PCR and ELISA, respectively. AP-1 and C/EBP DNA-binding activity and IL-24 promoter activity were assessed by EMSA analysis and a reporter gene assay, respectively. IL-24 mRNA expression was significantly elevated in active lesions from patients who have ulcerative colitis and Crohn’s disease. Colonic SEMFs were identified as a major source of IL-24 in the mucosa. IL-1β, but not IL-17A, TNF-α, or IFN-γ, significantly enhanced IL-24 mRNA and protein expression in isolated colonic SEMFs. The IL-1β-induced IL-24 mRNA expression was mediated by the activation of the transcription factors, AP-1 and C/EBP-β. Induction of IL-24 mRNA stabilization was also involved in the effects of IL-1β. IL-24 induced JAK1/STAT-3 phosphorylation and SOCS3 expression in HT-29 colonic epithelial cells. IL-24 did not modulate the proliferation of HT-29 cells, but significantly increased the mRNA expression of membrane-bound mucins (MUC1, MUC3, and MUC4). IL-24 derived from colonic SEMFs acts on colonic epithelial cells to elicit JAK1/STAT-3 activation and the expression of SOCS3 and mucins, supporting their suppressive effects on mucosal inflammation in IBD.
Fusion Loop Peptide of the West Nile Virus Envelope Protein Is Essential for Pathogenesis and Is Recognized by a Therapeutic Cross-Reactive Human Monoclonal Antibody
Authors: Sultana Hameeda , Foellmer Harald G. , Neelakanta Girish , Oliphant Theodore , Engle Michael , Ledizet Michel , Krishnan Manoj N. , Bonafé Nathalie , Anthony Karen G. , Marasco Wayne A. , Kaplan Paul , Montgomery Ruth R. , Diamond Michael S. , Koski Raymond A. , Fikrig Erol 
Published: June 2009

Abstract
West Nile virus is an emerging pathogen that can cause fatal neurological disease. A recombinant human mAb, mAb11, has been described as a candidate for the prevention and treatment of West Nile disease. Using a yeast surface display epitope mapping assay and neutralization escape mutant, we show that mAb11 recognizes the fusion loop, at the distal end of domain II of the West Nile virus envelope protein. Ab mAb11 cross-reacts with all four dengue viruses and provides protection against dengue (serotypes 2 and 4) viruses. In contrast to the parental West Nile virus, a neutralization escape variant failed to cause lethal encephalitis (at higher infectious doses) or induce the inflammatory responses associated with blood-brain barrier permeability in mice, suggesting an important role for the fusion loop in viral pathogenesis. Our data demonstrate that an intact West Nile virus fusion loop is critical for virulence, and that human mAb11 targeting this region is efficacious against West Nile virus infection. These experiments define the molecular determinant on the envelope protein recognized by mAb11 and demonstrate the importance of this region in causing West Nile encephalitis.
Macrophage Delivery of Nanoformulated Antiretroviral Drug to the Brain in a Murine Model of NeuroAIDS
Authors: Dou Huanyu , Grotepas Cassi B. , McMillan JoEllyn M. , Destache Christopher J. , Chaubal Mahesh , Werling Jane , Kipp James , Rabinow Barrett , Gendelman Howard E. 
Published: June 2009

Abstract
Antiretroviral therapy (ART) shows variable blood-brain barrier penetration. This may affect the development of neurological complications of HIV infection. In attempts to attenuate viral growth for the nervous system, cell-based nanoformulations were developed with the focus on improving drug pharmacokinetics. We reasoned that ART carriage could be facilitated within blood-borne macrophages traveling across the blood-brain barrier. To test this idea, an HIV-1 encephalitis (HIVE) rodent model was used where HIV-1-infected human monocyte-derived macrophages were stereotactically injected into the subcortex of severe combined immunodeficient mice. ART was prepared using indinavir (IDV) nanoparticles (NP, nanoART) loaded into murine bone marrow macrophages (BMM, IDV-NP-BMM) after ex vivo cultivation. IDV-NP-BMM was administered i.v. to mice resulting in continuous IDV release for 14 days. Rhodamine-labeled IDV-NP was readily observed in areas of HIVE and specifically in brain subregions with active astrogliosis, microgliosis, and neuronal loss. IDV-NP-BMM treatment led to robust IDV levels and reduced HIV-1 replication in HIVE brain regions. We conclude that nanoART targeting to diseased brain through macrophage carriage is possible and can be considered in developmental therapeutics for HIV-associated neurological disease.
T-bet Knockout Prevents Helicobacter felis-Induced Gastric Cancer
Authors: Stoicov Calin , Fan Xueli , Liu Jian Hua , Bowen Glennice , Whary Mark , Kurt-Jones Evelyn , Houghton JeanMarie 
Published: June 2009

Abstract
Helicobacter infection is the primary risk factor for gastric cancer, with the cytokine environment within the gastric mucosa the strongest predictor of disease risk. Elevated TNF-α, IL-1β, and low IL-10 are associated with the highest risk. In this study, we used C57BL/6 mice to identify T-bet as a central regulator of the cytokine environment during Helicobacter felis infection. We infected male and female C57BL/6 and C57BL/6-T-bet knockout (KO) liter mates with H. felis and examined the bacterial colonization, immune response, and mucosal damage at varying time points. T-bet KO mice maintained infection for 15 mo at similar levels to wild-type mice. Infection and immune response did not differ between male and female mice. Despite sustained infection, T-bet KO mice respond with a blunted Th1 response associated with preservation of parietal and chief cells and protection from the development of gastric cancer. Unexpectedly, T-bet KO mice develop a gastric environment that would not be expected based on the phenotype of T-bet KO CD4 cells alone. T-bet KO mice respond to H. felis infection with a markedly blunted IL-1β and TNF-α and elevated IL-10 levels. Activity of this one master regulator modulates the expression of the key gastric mucosal cytokines associated with gastric cancer and may be a target for therapy to restore immune balance clinically in patients at risk for gastric cancer.
Binding of Submaximal C1q Promotes Complement-Dependent Cytotoxicity (CDC) of B Cells Opsonized with Anti-CD20 mAbs Ofatumumab (OFA) or Rituximab (RTX): Considerably Higher Levels of CDC Are Induced by OFA than by RTX
Authors: Pawluczkowycz Andrew W. , Beurskens Frank J. , Beum Paul V. , Lindorfer Margaret A. , van de Winkel Jan G. J. , Parren Paul W. H. I. , Taylor Ronald P. 
Published: June 2009

Abstract
The CD20 mAb ofatumumab (OFA) is more effective than rituximab (RTX) in promoting complement-dependent cytotoxicity (CDC) of B cells via the classical pathway (CP) of complement. CP activation is initiated by C1q binding to cell-bound IgG. Therefore, we examined the role of C1q in the dynamics of complement activation and CDC of B cell lines and primary cells from patients with chronic lymphocytic leukemia, reacted with OFA or RTX. C1q binding, complement activation, and colocalization of C1q with cell-bound mAbs were determined by flow cytometry and high-resolution digital imaging. C1q binds avidly to OFA-opsonized Raji and Daudi cells (KD = 12–16 nM) and colocalizes substantially with cell-bound OFA. Cells opsonized with OFA undergo high levels of complement activation and CDC in C1q-depleted serum supplemented with low concentrations of C1q. Under comparable conditions, RTX-opsonized cells bind less C1q; in addition, even when higher concentrations of C1q are used to achieve comparable C1q binding to RTX-opsonized cells, less complement activation and CDC are observed. Greater CDC induced by OFA may occur because C1q is bound in close proximity and with high avidity to OFA, resulting in effective CP activation. Moreover, OFA binds to the small, extracellular CD20 loop, placing the mAb considerably closer to the cell membrane than does RTX. This may facilitate effective capture and concentration of activated complement components closer to the cell membrane, potentially shielding them from inactivation by fluid phase agents and promoting efficient generation of the membrane attack complex.
Cutting Edge: B and T Lymphocyte Attenuator Signaling on NKT Cells Inhibits Cytokine Release and Tissue Injury in Early Immune Responses
Authors: Miller Mendy L. , Sun Yonglian , Fu Yang-Xin 
Published: June 2009

Abstract
The role of coinhibition in an immune response is thought to be critical for the contraction of an adaptive immune response in its waning phases. We present evidence that B and T lymphocyte attenuator (BTLA) coinhibitory signaling is required to temper early inflammation. Using an in vivo Con A challenge model of acute hepatitis, we observed reduced survival and increased early serum cytokine secretion in BTLA−/− mice as compared with wild-type mice. In vitro, liver mononuclear cells from BTLA−/− mice are hyperresponsive to anti-CD3, Con A, and α-galactosylceramide stimulation and secrete higher levels of TNF-α, IFN-γ, IL-2, and IL-4. We found this was in part due to negative regulation of NKT cells by BTLA, as early cytokine inhibition from whole liver mononuclear cells or purified NKT cells depends upon BTLA signaling. Overall, our data demonstrate that coinhibition is active in early immune responses through BTLA regulation of NKT cells.
Chemotherapeutic Agents in Noncytotoxic Concentrations Increase Antigen Presentation by Dendritic Cells via an IL-12-Dependent Mechanism
Authors: Shurin Galina V. , Tourkova Irina L. , Kaneno Ramon , Shurin Michael R. 
Published: June 2009

Abstract
Antineoplastic chemotherapeutic agents may indirectly activate dendritic cells (DCs) by inducing the release of “danger” signals from dying tumor cells. Whereas the direct cytotoxic or inhibitory effect of conventional chemotherapy on DCs has been reported, modulation of DC function by chemotherapeutic agents in low noncytotoxic concentrations has not yet been investigated. We have tested the effects of different classes of antineoplastic chemotherapeutic agents used in low noncytotoxic concentrations on the Ag-presenting function of DCs. We revealed that paclitaxel, doxorubicin, mitomycin C, and methotrexate up-regulated the ability of DCs to present Ags to Ag-specific T cells. Stimulation of DC function was associated with the up-regulation of expression of Ag-processing machinery components and costimulatory molecules on DCs, as well as increased IL-12p70 expression. However, the ability of DCs treated with paclitaxel, methotrexate, doxorubicin, and vinblastine to increase Ag presentation to Ag-specific T cells was abolished in DCs generated from IL-12 knockout mice, indicating that up-regulation of Ag presentation by DCs is IL-12-dependent and mediated by the autocrine or paracrine mechanisms. At the same time, IL-12 knockout and wild-type DCs demonstrated similar capacity to up-regulate OVA presentation after their pretreatment with low concentrations of mitomycin C and vincristine, suggesting that these agents do not utilize IL-12-mediated pathways in DCs for stimulating Ag presentation. These findings reveal a new mechanism of immunopotentiating activity of chemotherapeutic agents—a direct immunostimulatory effect on DCs (chemomodulation)—and thus provide a strong rationale for further assessment of low-dose chemotherapy given with DC vaccines for cancer treatment.