bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence for Phagocytosis of Influenza Virus-Infected, Apoptotic Cells by Neutrophils and Macrophages in Mice
Authors: Hashimoto Yumi , Moki Takeshi , Takizawa Takenori , Shiratsuchi Akiko , Nakanishi Yoshinobu 
Published: April 2014

Abstract
Influenza virus-infected cells undergo apoptosis and become susceptible to phagocytosis by macrophages in vitro, and this leads to the propagation of the virus being inhibited. We previously showed that inhibitors of phagocytosis increased the rate of mortality among influenza virus-infected mice. However, the mode of the phagocytosis of influenza virus-infected cells in vivo has not been investigated. We, in this study, assessed this issue by histochemically analyzing bronchoalveolar lavage cells and lung tissue obtained from C57BL/6 mice infected with influenza A/WSN (H1N1) virus. Both neutrophils and macrophages accumulated in the lung soon after the viral challenge, and either type of cell was capable of phagocytosing influenza virus-infected, apoptotic cells. Changes in the level of phagocytosis and the amount of virus in lung tissue roughly correlated with each other. Furthermore, alveolar macrophages prepared from influenza virus-infected mice showed greater phagocytic activity than those from uninfected mice. The phagocytic activity of macrophages was stimulated in vitro by a heat-labile substance(s) released from influenza virus-infected cells undergoing apoptosis. These results suggested that the level of phagocytosis is augmented both quantitatively and qualitatively in the lung of influenza virus-infected animals so that infected cells are effectively eliminated. Finally, lack of TLR4 caused an increase in the rate of mortality among influenza virus-challenged mice and a decrease in the level of phagocytosis of apoptotic cells in the lung. TLR4 could thus play an important role in the host defense against influenza by positively regulating the phagocytic elimination of infected cells.
FTY720 Ameliorates Th1-Mediated Colitis in Mice by Directly Affecting the Functional Activity of CD4+CD25+ Regulatory T Cells
Authors: Daniel Carolin , Sartory Nico , Zahn Nadine , Geisslinger Gerd , Radeke Heinfried H. , Stein Juergen M. 
Published: April 2014

Abstract
Following the present concepts, the synthetic sphingosine analog of myriocin FTY720 alters migration and homing of lymphocytes via sphingosine 1-phosphate receptors. However, several studies indicate that the immunosuppressive properties of FTY720 may alternatively be due to tolerogenic activities via modulation of dendritic cell differentiation or based on direct effects on CD4+CD25+ regulatory T cells (Treg). As Treg play an important role for the cure of inflammatory colitis, we used the Th1-mediated 2,4,6-trinitrobenzene sulfonic acid (TNBS) colitis model to address the therapeutic potential of FTY720 in vivo. A rectal enema of TNBS was given to BALB/c mice. FTY720 was administered i.p. from days 0 to 3 or 3 to 5. FTY720 substantially reduced all clinical, histopathologic, macroscopic, and microscopic parameters of colitis analyzed. The therapeutic effects of FTY720 were associated with a down-regulation of IL-12p70 and subsequent Th1 cytokines. Importantly, FTY720 treatment resulted in a prominent up-regulation of FoxP3, IL-10, TGFβ, and CTLA4. Supporting the hypothesis that FTY720 directly affects functional activity of CD4+CD25+ Treg, we measured a significant increase of CD25 and FoxP3 expression in isolated lamina propria CD4+ T cells of FTY720-treated mice. The impact of FTY720 on Treg induction was further confirmed by concomitant in vivo blockade of CTLA4 or IL-10R which significantly abrogated its therapeutic activity. In conclusion, our data provide clear evidence that in addition to its well-established effects on migration FTY720 leads to a specific down-regulation of proinflammatory signals while simultaneously inducing functional activity of CD4+CD25+ Treg. Thus, FTY720 may offer a promising new therapeutic strategy for the treatment of IBD.
Regulation of Th2 Cytokine Genes by p38 MAPK-Mediated Phosphorylation of GATA-3
Authors: Maneechotesuwan Kittipong , Xin Yao , Ito Kazuhiro , Jazrawi Elen , Lee Kang-Yun , Usmani Omar S. , Barnes Peter J. , Adcock Ian M. 
Published: April 2014

Abstract
GATA-3 plays a critical role in allergic diseases by regulating the release of cytokines from Th2 lymphocytes. However, the molecular mechanisms involved in the regulation of GATA-3 in human T lymphocytes are not yet understood. Using small interfering RNA to knock down GATA-3, we have demonstrated its critical role in regulating IL-4, IL-5, and IL-13 release from a human T cell line. Specific stimulation of T lymphocytes by costimulation of CD3 and CD28 to mimic activation by APCs induces translocation of GATA-3 from the cytoplasm to the nucleus, with binding to the promoter region of Th2 cytokine genes, as determined by chromatin immunoprecipitation. GATA-3 nuclear translocation is dependent on its phosphorylation on serine residues by p38 MAPK, which facilitates interaction with the nuclear transporter protein importin-α. This provides a means whereby allergen exposure leads to the expression of Th2 cytokines, and this novel mechanism may provide new approaches to treating allergic diseases.
CD43 Collaborates with P-Selectin Glycoprotein Ligand-1 to Mediate E-Selectin-Dependent T Cell Migration into Inflamed Skin
Authors: Matsumoto Masanori , Shigeta Akiko , Furukawa Yuko , Tanaka Toshiyuki , Miyasaka Masayuki , Hirata Takako 
Published: April 2014

Abstract
Activated T cell migration into nonlymphoid tissues is initiated by the interactions of P- and E-selectin expressed on endothelial cells and their ligands on T cells. P-selectin glycoprotein ligand-1 (PSGL-1) has been the only E-selectin ligand demonstrated to function during the in vivo migration of activated T cells. We show in this study that CD43-deficient Th1 cells, like PSGL-1-deficient cells, exhibited reduced E-selectin-binding activity compared with wild-type cells. Th1 cells with a PSGL-1 and CD43 double deficiency showed even less E-selectin-binding activity. In migration assays in which adoptively transferred cells migrate to inflamed skin P- and E-selectin dependently, CD43 contributed significantly to PSGL-1-independent Th1 cell migration. In addition, in vivo activated T cells from the draining lymph nodes of sensitized mice deficient in PSGL-1 and/or CD43 showed significantly decreased E-selectin-binding activity and migration efficiency, with T cells from double-deficient mice showing the most profound decrease. Collectively, these results demonstrate that the CD43 expressed on activated T cells functions as an E-selectin ligand and thereby mediates T cell migration to inflamed sites, in collaboration with PSGL-1.
Cutting Edge: Bim Is Required for Superantigen-Mediated B Cell Death
Authors: Goodyear Carl S. , Corr Maripat , Sugiyama Fujimi , Boyle David L. , Silverman Gregg J. 
Published: April 2014

Abstract
To impair B cell clonal regulation, the microbial virulence factor, protein A of Staphylococcus aureus, can interact with evolutionarily conserved BCR-binding sites to induce a form of Fas-independent activation-associated B cell death that results in selective immune tolerance. We now show that this in vivo death pathway is associated with induction of increased transcript and protein levels of Bim, a BH3-only proapoptotic Bcl-2 family protein, which is inhibited by excess B cell-activating factor. An absolute requirement for Bim was documented, since Bim-deficient B cells were protected from in vivo superantigen-induced death and instead underwent persistent massive supraclonal expansion without functional impairment. These studies characterize a BCR-dependent negative clonal selection pathway that has been co-opted by a common bacterial pathogen to induce selective defects in host immune defenses.
Fetal Immune Responses to Plasmodium falciparum Antigens in a Malaria-Endemic Region of Cameroon
Authors: Metenou Simon , Suguitan Amorsolo L. , Long Carole , Leke Rose G. F. , Taylor Diane Wallace 
Published: April 2014

Abstract
Plasmodium falciparum infection during pregnancy can lead to the transplacental passage of malarial Ags that are capable of inducing acquired immune responses in the fetus. Studies have identified cytokines produced by malaria-specific cord blood (CB) T cells, but information on fetal B cells is limited. Thus, CB mononuclear cells from 120 Cameroonian newborns were cultured for 7 days in vitro and supernatants were assessed by ELISA for Abs to an extract of malarial schizonts (MA), recombinant apical merozoite Ag 1 (AMA-1), the 42-kDa C-terminal region of merozoite surface protein 1 (MSP-142), a B epitope of ring-infected erythrocyte surface Ag (RESA), and the dominant B epitope of the circumsporozoite protein (CSP). Only 12% of supernatants contained IgM to MA but 78% had IgG to one or more malarial Ags, with 53% having IgG to AMA-1, 38% to MSP-142, 3% to RESA, and 0% to CSP. The Abs to AMA-1 and MSP-142 were predominantly IgG1 and IgG3. CB mononuclear cells were also tested for the ability to secrete cytokines in response to MA and a pool of conserved MSP-1 T cell epitopes. Among the Ag-reactive samples, 39.3% produced only Th2-type cytokines, whereas 60.6% produced a combination of Th1- and Th2-type cytokines. Although a Th2 bias was observed, the in utero cytokine environment was adequate to support isotype switching to cytophilic IgGs, the isotypes that are protective in adults. Because many infants living in a low transmission area are born with malaria-specific B and T cells, the influence of in utero priming on neonatal immunity merits further investigation.
Lack of Effective MUC1 Tumor Antigen-Specific Immunity in MUC1-Transgenic Mice Results from a Th/T Regulatory Cell Imbalance That Can Be Corrected by Adoptive Transfer of Wild-Type Th Cells
Authors: Turner Michael S. , Cohen Patrice A. , Finn Olivera J. 
Published: April 2014

Abstract
Glycoprotein tumor Ag MUC1 is overexpressed on the majority of epithelial adenocarcinomas. CTLs that recognize MUC1 and can kill tumor cells that express this molecule have been found in cancer patients, yet they are present in low frequency and unable to eradicate MUC1+ tumors. Patients also make anti-MUC1 Abs but predominantly of the IgM isotype reflecting the lack of effective MUC1-specific Th responses. Mice transgenic for the human MUC1 gene (MUC1-Tg) are similarly hyporesponsive to MUC1. We used a vaccine consisting of dendritic cells loaded with a long synthetic MUC1 peptide to investigate the fate and function of MUC1-specific CD4+ Th elicited in wild-type (WT) or MUC1-Tg mice or adoptively transferred from vaccinated WT mice. We show that hyporesponsiveness of MUC1-Tg mice to this vaccine is a result of insufficient expansion of Th cells, while at the same time their regulatory T cells are efficiently expanded to the same extent as in WT mice and exert a profound suppression on MUC1-specific B and T cell responses in vivo. Adoptive transfer of WT Th cells relieved this suppression and enhanced T and B cell responses to subsequent MUC1 immunization. Our data suggest that the balance between Th and regulatory T cells is a critical parameter that could be modulated to improve the response to cancer vaccines.
Effect of Both Ultraviolet B Irradiation and Histamine Receptor Function on Allergic Responses to an Inhaled Antigen
Authors: McGlade Jacqueline P. , Gorman Shelley , Lenzo Jason C. , Tan Jamie W. , Watanabe Takeshi , Finlay-Jones John J. , Thomas Wayne R. , Hart Prue H. 
Published: April 2014

Abstract
Exposure of skin to UVB radiation (290–320 nm) modulates the immune system, with most studies showing a suppression of Th1-driven immune responses. This study investigated the effects of UVB on Th2-associated immune responses using a murine model of allergic respiratory inflammation. C57BL/6, histamine receptor-1 knockout (H1RKO), and histamine receptor-2 knockout (H2RKO) mice were exposed to a single 4 kJ/m2 dose of UVB (twice a minimal edemal dose) on shaved dorsal skin 3 days before intranasal sensitization with papain, a cysteine protease homologue of the dust mite allergen Der p 1. H1RKO mice demonstrated enhanced papain-specific inflammatory responses in the lung-draining lymph nodes (LDLNs), whereas the responses of H2RKO mice closely mimicked those of C57BL/6 mice. UVB irradiation 3 days before sensitization reduced in vitro papain-specific proliferation of LDLN cells of C57BL/6 and H1RKO mice but not H2RKO mice 24 h after challenge. The regulatory effect of UVB was transferred by adoptive transfer of unfractionated LDLN cells from UVB-irradiated, papain-sensitized C57BL/6 and H1RKO donor mice in naive recipients of the corresponding strain that were subsequently sensitized and challenged with papain. Additionally, UVB exposure suppressed papain-induced IL-5 and IL-10 production in vitro by LDLN cells from H1RKO mice but not from C57BL/6 mice or H2RKO mice. The results of this study demonstrate systemic immunomodulation of responses to intranasally delivered Ag by UVB irradiation and implicate a role for the H2 receptor in UVB-induced suppression of Ag-specific responses in the draining lymph nodes.
Staphylococcus aureus Protein A Triggers T Cell-Independent B Cell Proliferation by Sensitizing B Cells for TLR2 Ligands
Authors: Bekeredjian-Ding Isabelle , Inamura Seiichi , Giese Thomas , Moll Hermann , Endres Stefan , Sing Andreas , Zähringer Ulrich , Hartmann Gunther 
Published: April 2014

Abstract
B cells possess functional characteristics of innate immune cells, as they can present Ag to T cells and can be stimulated with microbial molecules such as TLR ligands. Because crude preparations of Staphylococcus aureus are frequently used as polyclonal B cell activators and contain potent TLR2 activity, the scope of this study was to analyze the impact of S. aureus-derived TLR2-active substances on human B cell activation. Peripheral B cells stimulated with chemically modified S. aureus cell wall preparations proliferated in response to stimulation with crude cell wall preparations but failed to be activated with pure peptidoglycan, indicating that cell wall molecules other than peptidoglycan are responsible for B cell proliferation. Subsequent analysis revealed that surface protein A (SpA), similar to BCR cross-linking with anti-human Ig, sensitizes B cells for the recognition of cell wall-associated TLR2-active lipopeptides (LP). In marked contrast to TLR7- and TLR9-triggered B cell stimulation, stimulation with TLR2-active LP and SpA or with crude cell wall preparations failed to induce IgM secretion, thereby revealing qualitative differences in TLR2 signaling compared with TLR7/9 signaling. Notably, combined stimulation with SpA plus TLR2 ligands induced vigorous proliferation of a defined B cell subset that expressed intracellular IgM in the presence of IL-2. Conclusion: S. aureus triggers B cell activation via SpA-induced sensitization of B cells for TLR2-active LP. Combined SpA and TLR2-mediated B cell activation promotes B cell proliferation but fails to induce polyclonal IgM secretion as seen after TLR7 and TLR9 ligation.
Tumor Cells Loaded with α-Galactosylceramide Induce Innate NKT and NK Cell-Dependent Resistance to Tumor Implantation in Mice
Authors: Shimizu Kanako , Goto Akira , Fukui Mikiko , Taniguchi Masaru , Fujii Shin-ichiro 
Published: April 2014

Abstract
Dendritic cells (DCs) loaded with α-galactosylceramide (α-GalCer) are known to be active APCs for the stimulation of innate NKT and NK cell responses in vivo. In this study, we evaluated the capacity of non-DCs to present α-GalCer in vitro and in vivo, particularly tumor cells loaded with α-GalCer (tumor/Gal). Even though the tumor cells lacked expression of CD40, CD80, and CD86 costimulatory molecules, the i.v. injection of tumor/Gal resulted in IFN-γ secretion by NKT and NK cells. These innate responses to tumor/Gal, including the induction of IL-12p70, were comparable to or better than α-GalCer-loaded DCs. B16 melanoma cells that were stably transduced to express higher levels of CD1d showed an increased capacity relative to wild-type B16 cells to present α-GalCer in vivo. Three different tumor cell lines, when loaded with α-GalCer, failed to establish tumors upon i.v. injection, and the mice survived for at least 6 mo. The resistance against tumor cells was independent of CD4 and CD8 T cells but dependent upon NKT and NK cells. Mice were protected from the development of metastases if the administration of live B16 tumor cells was followed 3 h or 3 days later by the injection of CD1dhigh-α-GalCer-loaded B16 tumor cells with or without irradiation. Taken together, these results indicate that tumor/Gal are effective APCs for innate NKT and NK cell responses, and that these innate immune responses are able to resist the establishment of metastases in vivo.
Induced SHIP Deficiency Expands Myeloid Regulatory Cells and Abrogates Graft-versus-Host Disease
Authors: Paraiso Kim H. T. , Ghansah Tomar , Costello Amy , Engelman Robert W. , Kerr William G. 
Published: April 2014

Abstract
Graft-vs-host disease (GVHD) is the leading cause of treatment-related death in allogeneic bone marrow (BM) transplantation. Immunosuppressive strategies to control GVHD are only partially effective and often lead to life-threatening infections. We previously showed that engraftment of MHC-mismatched BM is enhanced and GVHD abrogated in recipients homozygous for a germline SHIP mutation. In this study, we report the development of a genetic model in which SHIP deficiency can be induced in adult mice. Using this model, we show that the induction of SHIP deficiency in adult mice leads to a rapid and significant expansion of myeloid suppressor cells in peripheral lymphoid tissues. Consistent with expansion of myeloid suppressor cells, splenocytes and lymph node cells from adult mice with induced SHIP deficiency are significantly compromised in their ability to prime allogeneic T cell responses. These results demonstrate that SHIP regulates homeostatic signals for these immunoregulatory cells in adult physiology. Consistent with these findings, induction of SHIP deficiency before receiving a T cell-replete BM graft abrogates acute GVHD. These findings indicate strategies that target SHIP could increase the efficacy and utility of allogeneic BM transplantation, and thereby provide a curative therapy for a wide spectrum of human diseases.
Mcl-1 Depletion in Apoptosis Elicited by Ionizing Radiation in Peritoneal Resident Macrophages of C3H Mice
Authors: Kubota Yoshihisa , Kinoshita Keiji , Suetomi Katsutoshi , Fujimori Akira , Takahashi Sentaro 
Published: April 2014

Abstract
Remarkably, apoptosis was induced by exposing peritoneal resident macrophages (PRM) of C3H mice, but not other strains of mice, to ionizing radiation. The molecular mechanism of this strain-specific apoptosis in PRM was studied. The apoptosis elicited in C3H mouse PRM 4 h after exposure was effectively blocked by proteasome inhibitors. Irradiation-induced disruption of mitochondrial transmembrane potential and the release of cytochrome c into the cytosol were also suppressed by a proteasome inhibitor but not by a caspase inhibitor. To determine whether the apoptosis occurred due to a depletion of antiapoptotic proteins, Bcl-2 family proteins were examined. Irradiation markedly decreased the level of Mcl-1, but not Bcl-2, Bcl-XL, Bax, A1, or cIAP1. Mcl-1’s depletion was suppressed by a proteasome inhibitor but not by a caspase inhibitor. The amount of Mcl-1 was well correlated with the rate of apoptosis in C3H mouse PRM exposed to irradiation and not affected by irradiation in radioresistant B6 mouse PRM. Irradiation increased rather than decreased the Mcl-1 mRNA expression in C3H mouse PRM. On the other hand, Mcl-1 protein synthesis was markedly suppressed by irradiation. Global protein synthesis was also suppressed by irradiation in C3H mouse PRM but not in B6 mouse PRM. The down-regulation of Mcl-1 expression with Mcl-1-specific small interfering RNA or antisense oligonucleotide significantly induced apoptosis in both C3H and B6 mouse PRM without irradiation. It was concluded that the apoptosis elicited in C3H mouse PRM by ionizing radiation was attributable to the depletion of Mcl-1 through radiation-induced arrest of global protein synthesis.
Peroxisome Proliferator-Activated Receptor γ Is Required for Regulatory CD4+ T Cell-Mediated Protection against Colitis
Authors: Hontecillas Raquel , Bassaganya-Riera Josep 
Published: April 2014

Abstract
Peroxisome proliferator-activated receptor (PPAR) γ activation has been implicated in the prevention of immunoinflammatory disorders; however, the mechanisms of regulation of effector and regulatory CD4+ T cell functions by endogenously activated PPAR-γ remain unclear. We have used PPAR-γ-deficient CD4+ T cells obtained from tissue-specific PPAR-γ null mice (i.e., PPAR-γ fl/fl; MMTV-Cre+) to investigate the role of endogenous PPAR-γ on regulatory T cell (Treg) and effector CD4+ T cell function. Overall, we show that the loss of PPAR-γ results in enhanced Ag-specific proliferation and overproduction of IFN-γ in response to IL-12. These findings correlate in vivo with enhanced susceptibility of tissue-specific PPAR-γ null mice to trinitrobenzene sulfonic acid-induced colitis. Furthermore, the transfer of purified PPAR-γ null CD4+ T cells into SCID recipients results in enteric disease. To test the assertion that the deficiency of PPAR-γ in Treg impairs their ability to prevent effector T cell-induced colitis, we performed cotransfer studies. These studies demonstrate that PPAR-γ-expressing, but not PPAR-γ null Treg, prevent colitis induced by transfer of naive CD4+ T cells into SCID recipients. In line with these findings, the production of IFN-γ by spleen and mesenteric lymph node-derived CD4+ T cells was down-regulated following transfer of PPAR-γ-expressing, but not PPAR-γ null, Treg. In conclusion, our data suggest that endogenous PPAR-γ activation represents a Treg intrinsic mechanism of down-regulation of effector CD4+ T cell function and prevention of colitis.
CC Chemokine Receptor 7 Contributes to Gi-Dependent T Cell Motility in the Lymph Node
Authors: Okada Takaharu , Cyster Jason G. 
Published: April 2014

Abstract
Naive T cells migrate extensively within lymph node (LN) T zones to scan for Ag-bearing dendritic cells. However, the extracellular signals controlling T cell motility in LNs are not well defined. In this study, by real-time imaging of LNs, we show that the inhibition of Gi signaling in T cells severely impairs their migration. The chemokine CCL21, a ligand of CCR7, strongly induces chemokinesis in vitro, and T cell motility in LNs from CCR7 ligand-deficient plt/plt mice was reduced. CCR7-deficient T cells in wild-type LNs showed a similar reduction in motility, and antagonism of CXCR4 function did not further decrease their motility. The effect of CCR7 or CCR7-ligand deficiency could account for ∼40% of the Gi-dependent motility. These results reveal a role for CCR7 in promoting T cell migration within lymphoid organ T zones, and they suggest the additional involvement of novel Gi-coupled receptors in promoting T cell motility at these sites.