bluuebunny/crossref_metadata_2025_split huggingface dataset:
IL-6-Dependent Mucosal Protection Prevents Establishment of a Microbial Niche for Attaching/Effacing Lesion-Forming Enteric Bacterial Pathogens
Authors: Dann Sara M. , Spehlmann Martina E. , Hammond Dustin C. , Iimura Mitsutoshi , Hase Koji , Choi Lillian J. , Hanson Elaine , Eckmann Lars 
Published: April 2014

Abstract
Enteric infections with attaching/effacing lesion-inducing bacterial pathogens are a worldwide health problem. A murine infection model with one such pathogen, Citrobacter rodentium, was used to elucidate the importance of the pleiotropic immune regulator, IL-6, in the pathogenesis of infection. IL-6 was strongly induced in colonic epithelial cells and macrophages upon C. rodentium infection and was required for effective host defense, because mice lacking IL-6 failed to control bacterial numbers 2–3 wk after infection and exhibited increased mortality. IL-6 was not needed for mounting effective T and B cell responses to the pathogens, nor was it important for induction of IFN-γ or TNF-α, cytokines involved in host defense against the bacteria, or the antibacterial effector, NO. Instead, IL-6 played a key role in mucosal protection, since its absence was associated with marked infection-induced apoptosis in the colonic epithelium and subsequent ulcerations. Cell culture studies confirmed that IL-6 protected colon epithelial cells directly against inducible apoptosis, which was accompanied by increased expression of an array of genes encoding antiapoptotic proteins, including Bcl-xL, Mcl-1, cIAP-2, and Bcl-3. Ulcerations appeared to be pathogenetically important, because bacteria localized preferentially to those regions, and chemically induced colonic ulcerations promoted bacterial colonization. Furthermore, blood components likely present in ulcer exudates, particularly alanine, asparagine, and glycine, promoted bacterial growth. Thus, IL-6 is an important regulator of host defense against C. rodentium by protecting the mucosa against ulcerations which can act as a microbial niche for the bacteria.
CEACAM1 Dynamics during Neisseria gonorrhoeae Suppression of CD4+ T Lymphocyte Activation
Authors: Lee Hannah S. W. , Ostrowski Mario A. , Gray-Owen Scott D. 
Published: April 2014

Abstract
Neisseria gonorrhoeae colony opacity-associated (Opa) proteins bind to human carcinoembryonic antigen cellular adhesion molecules (CEACAM) found on host cells including T lymphocytes. Opa binding to CEACAM1 suppresses the activation of CD4+ T cells in response to a variety of stimuli. In this study, we use primary human CD4+ T cells isolated from peripheral blood to define the molecular events occurring subsequent to Opa-CEACAM1 binding. We establish that, in contrast to other cell types, T cells do not engulf N. gonorrhoeae upon CEACAM1 binding. Instead, the bacteria recruit CEACAM1 from intracellular stores and maintain it on the T cell surface. Upon TCR ligation, the co-engaged CEACAM1 becomes phosphorylated on tyrosine residues within the ITIMs apparent in the cytoplasmic domain. This allows the recruitment and subsequent activation of the src homology domain 2-containing tyrosine phosphatases SHP-1 and SHP-2 at the site of bacterial attachment, which prevents the normal tyrosine phosphorylation of the CD3ζ-chain and ZAP-70 kinase in response to TCR engagement. Combined, this dynamic response allows the bacteria to effectively harness the coinhibitory function of CEACAM1 to suppress the adaptive immune response at its earliest step.
Reduced Nicotinamide Adenine Dinucleotide Phosphate Oxidase-Independent Resistance to Aspergillus fumigatus in Alveolar Macrophages
Authors: Cornish E. Jean , Hurtgen Brady J. , McInnerney Kate , Burritt Nancy L. , Taylor Ross M. , Jarvis James N. , Wang Shirley Y. , Burritt James B. 
Published: April 2014

Abstract
The fungal pathogen Aspergillus fumigatus is responsible for increasing numbers of fatal infections in immune-compromised humans. Alveolar macrophages (AM) are important in the innate defense against aspergillosis, but little is known about their molecular responses to fungal conidia in vivo. We examined transcriptional changes and superoxide release by AM from C57BL/6 and gp91phox−/− mice in response to conidia. Following introduction of conidia into the lung, microarray analysis of AM showed the transcripts most strongly up-regulated in vivo to encode chemokines and additional genes that play a critical role in neutrophil and monocyte recruitment, indicating that activation of phagocytes represents a critical early response of AM to fungal conidia. Of the 73 AM genes showing ≥2-fold changes, 8 were also increased in gp91phox−/− mice by conidia and in C57BL/6 mice by polystyrene beads, suggesting a common innate response to particulate matter. Ingenuity analysis of the microarray data from C57BL/6 mice revealed immune cell signaling and gene expression as primary mechanisms of this response. Despite the well-established importance of phagocyte NADPH oxidase in resisting aspergillosis, we found no evidence of this mechanism in AM following introduction of conidia into the mouse lung using transcriptional, luminometry, or NBT staining analysis. In support of these findings, we observed that AM from C57BL/6 and gp91phox−/− mice inhibit conidial germination equally in vitro. Our results indicate that early transcription in mouse AM exposed to conidia in vivo targets neutrophil recruitment, and that NADPH oxidase-independent mechanisms in AM contribute to inhibition of conidial germination.
Lactoferrin Acts as an Alarmin to Promote the Recruitment and Activation of APCs and Antigen-Specific Immune Responses
Authors: de la Rosa Gonzalo , Yang De , Tewary Poonam , Varadhachary Atul , Oppenheim Joost J. 
Published: April 2014

Abstract
Lactoferrin is an 80-kDa iron-binding protein present at high concentrations in milk and in the granules of neutrophils. It possesses multiple activities, including antibacterial, antiviral, antifungal, and even antitumor effects. Most of its antimicrobial effects are due to direct interaction with pathogens, but a few reports show that it has direct interactions with cells of the immune system. In this study, we show the ability of recombinant human lactoferrin (talactoferrin alfa (TLF)) to chemoattract monocytes. What is more, addition of TLF to human peripheral blood or monocyte-derived dendritic cell cultures resulted in cell maturation, as evidenced by up-regulated expression of CD80, CD83, and CD86, production of proinflammatory cytokines, and increased capacity to stimulate the proliferation of allogeneic lymphocytes. When injected into the mouse peritoneal cavity, lactoferrin also caused a marked recruitment of neutrophils and macrophages. Immunization of mice with OVA in the presence of TLF promoted Th1-polarized Ag-specific immune responses. These results suggest that lactoferrin contributes to the activation of both the innate and adaptive immune responses by promoting the recruitment of leukocytes and activation of dendritic cells.
Host and Donor Immune Responses Contribute to Antiviral Effects of Amotosalen-Treated Donor Lymphocytes following Early Posttransplant Cytomegalovirus Infection
Authors: Hossain Mohammad S. , Roback John D. , Wang Fengrong , Waller Edmund K. 
Published: April 2014

AbstractWe have previously shown that amotosalen-treated splenocytes rescued allorecipients from a lethal dose of mouse CMV (MCMV) administered on day 0 in experimental parent C57BL/6→CB6F1 allogeneic bone marrow transplant. In this study, we investigated the mechanism of antiviral activity of amotosalen-treated donor splenocytes when sublethal MCMV infections were administered 7 days posttransplant. Recipients of 3 × 106 untreated splenocytes were used as control. Following MCMV infection, recipients of untreated splenocytes had 40% early mortality due to acute graft-vs-host disease compared with no deaths among recipients of 10 × 106 treated splenocytes. However, recipients of both types of donor splenocytes effectively cleared MCMV from their liver. Like the untreated CD8+ T cells, amotosalen-treated CD8+ T cells equally retained their in vivo CTL activity against MCMV early peptide-pulsed targets and expressed similar levels of granzyme B within 11 days of infection. In contrast to full donor chimerism in recipients of untreated splenocytes, recipients of amotosalen-treated splenocytes showed mixed chimerism with both donor spleen- and host-derived anti-MCMV CD8+ T cells in their blood and lymphoid organs, with significantly higher numbers of host-derived CD4−CD8− (double negative) T cells in the spleens of recipients of treated splenocytes compared with the recipients of untreated splenocytes. Additionally, recipients of amotosalen-treated splenocytes had lower levels of serum IFN-γ and TNF-α in response to MCMV infection compared with untreated recipients. Thus, adoptive immunotherapy with treated T cells is a novel therapeutic approach that facilitates hematopoietic engraftment and permits antiviral immunity of both donor and host T cells without graft-vs-host disease.
Agonists of Proteinase-Activated Receptor-2 Enhance IFN-γ-Inducible Effects on Human Monocytes: Role in Influenza A Infection
Authors: Feld Micha , Shpacovitch Victoria M. , Ehrhardt Christina , Kerkhoff Claus , Hollenberg Morley D. , Vergnolle Nathalie , Ludwig Stephan , Steinhoff Martin 
Published: April 2014

Abstract
Proteinase-activated receptor-2 (PAR2) is expressed by different types of human leukocytes and involved in the development of inflammatory and infectious diseases. However, its precise role in the regulation of human monocyte and macrophage function during viral infection remains unclear. Also, the ability of PAR2 agonists to enhance the effects induced by immune mediators during infection or inflammation is still poorly investigated. Therefore, we investigated the ability of a PAR2 agonist to enhance IFN-γ-induced suppression of influenza A virus replication in human monocytes. We found that this effect correlates with an increased abundance of IκBα after costimulation of cells with PAR2 agonist and IFN-γ. Remarkably, coapplication of PAR2 agonist and IFN-γ also enhances the effects of IFN-γ on IFN-γ-inducible protein 10 kDa release, and CD64 and αVβ3 surface expression by human monocytes. Together, these findings indicate a potentially protective role of PAR2 activation during the progression of influenza A virus infection. This effect could be associated with the ability of PAR2 agonists to enhance IFN-γ-induced protective effects on human monocytes.
Blockade of Virus Infection by Human CD4+ T Cells via a Cytokine Relay Network
Authors: Davis Ann M. , Hagan Kristan A. , Matthews Loderick A. , Bajwa Gagan , Gill Michelle A. , Gale Michael , Farrar J. David 
Published: April 2014

Abstract
CD4+ T cells directly participate in bacterial clearance through secretion of proinflammatory cytokines. Although viral clearance relies heavily on CD8+ T cell functions, we sought to determine whether human CD4+ T cells could also directly influence viral clearance through cytokine secretion. We found that IFN-γ and TNF-α, secreted by IL-12-polarized Th1 cells, displayed potent antiviral effects against a variety of viruses. IFN-γ and TNF-α acted directly to inhibit hepatitis C virus replication in an in vitro replicon system, and neutralization of both cytokines was required to block the antiviral activity that was secreted by Th1 cells. IFN-γ and TNF-α also exerted antiviral effects against vesicular stomatitis virus infection, but in this case, functional type I IFN receptor activity was required. Thus, in cases of vesicular stomatitis virus infection, the combination of IFN-γ and TNF-α secreted by human Th1 cells acted indirectly through the IFN-α/β receptor. These results highlight the importance of CD4+ T cells in directly regulating antiviral responses through proinflammatory cytokines acting in both a direct and indirect manner.
Heme Oxygenase-1 Protects against Neutrophil-Mediated Intestinal Damage by Down-Regulation of Neutrophil p47phox and p67phox Activity and O2− Production in a Two-Hit Model of Alcohol Intoxication and Burn Injury
Authors: Li Xiaoling , Schwacha Martin G. , Chaudry Irshad H. , Choudhry Mashkoor A. 
Published: April 2014

Abstract
Heme oxygenase-1 (HO-1) has been demonstrated to protect against tissue injury. Furthermore, HO-1 is also shown to be antioxidant. Our recent findings indicate that acute alcohol (EtOH) intoxication exacerbates postburn intestinal and lung tissue damage, and this was found to be neutrophil dependent. Because neutrophil-mediated tissue injury involves the release of superoxide anions (O2−), the present study examined the role of HO-1 in neutrophil O2− production following EtOH and burn injury. Furthermore, we investigated whether HO-1 antioxidant properties are mediated via modulation of p47phox and/or p67phox proteins. Male rats (∼250 g) were gavaged with EtOH to achieve a blood EtOH level of ∼100 mg/dL before burn or sham injury (∼12.5% total body surface area). Some rats were treated with HO-1 activator cobalt protoporphyrin IX chloride (Copp; 25 mg/kg body weight) at the time of injury. On day 1 after injury, we found that EtOH combined with burn injury significantly increased neutrophil O2− production and p47phox and p67phox activation and decreased caspase-3 activity and apoptosis. This was accompanied with a decrease in neutrophil HO-1 levels. The treatment of animals with HO-1 activator Copp normalized neutrophil HO-1, O2−, p47phox, and p67phox following EtOH and burn injury. The expression of caspase-3, however, was further decreased in Copp-treated sham and EtOH plus burn groups. Moreover, Copp treatment also prevented the increase in intestinal edema and permeability following EtOH and burn injury. Altogether, these findings provide a new insight into the mechanism by which HO-1 regulates neutrophil O2− production and protect the intestine from damage following EtOH and burn injury.
Enhanced Dendritic Cell Survival Attenuates Lipopolysaccharide-Induced Immunosuppression and Increases Resistance to Lethal Endotoxic Shock
Authors: Gautier Emmanuel L. , Huby Thierry , Saint-Charles Flora , Ouzilleau Betty , Chapman M. John , Lesnik Philippe 
Published: April 2014

Abstract
Impaired immune function and associated immunosuppression are hallmarks of septic syndromes. As part of an overall deactivation of the immune system, profound depletion of dendritic cells (DCs) occurs in both septic patients and septic mice. Such depletion of DCs is potentially associated with immunosuppression and with failure to induce a protective Th1 immune response; it may equally be predictive of fatal outcome in septic patients. To evaluate the impact of enhanced DC survival on LPS-induced immunosuppression and on survival after LPS-induced septic shock, we created a transgenic mouse model specifically overexpressing the human form of the antiapoptotic protein Bcl-2 in DCs (DC-hBcl-2 mice). DCs derived from DC-hBcl-2 mice exhibited higher resistance to maturation-induced apoptosis after LPS treatment both in vitro and in vivo. Moreover, prolongation of DC survival diminished sublethal LPS-induced DC loss and immunosuppression, with maintenance of the differentiation potential of Th1 cells and enhanced T cell activation. Such modulation of the immune response appears to constitute a key feature of the attenuated mortality observed after LPS-induced shock in DC-hBcl-2 mice. Our study therefore identifies DC death as a key determinant of endotoxin-induced immunosuppression and mortality in mice.
CD47 Deficiency Protects Mice from Lipopolysaccharide-Induced Acute Lung Injury and Escherichia coli Pneumonia
Authors: Su Xiao , Johansen Mette , Looney Mark R. , Brown Eric J. , Matthay Michael A. 
Published: April 2014

Abstract
CD47 modulates neutrophil transmigration toward the sites of infection or injury. Mice lacking CD47 are susceptible to Escherichia coli (E. coli) peritonitis. However, less is known concerning the role of CD47 in the development of acute lung inflammation and injury. In this study, we show that mice lacking CD47 are protected from LPS-induced acute lung injury and E. coli pneumonia with a significant reduction in pulmonary edema, lung vascular permeability, and bacteremia. Reconstitution of CD47+/− mice with CD47−/− neutrophils significantly reduced lung edema and neutrophil infiltration, thus demonstrating that CD47+ neutrophils are required for the development of lung injury from E. coli pneumonia. Importantly, CD47-deficient mice with E. coli pneumonia had an improved survival rate. Taken together, deficiency of CD47 protects mice from LPS-induced acute lung injury and E. coli pneumonia. Targeting CD47 may be a novel pathway for treatment of acute lung injury.
Development of a Novel Noncompetitive Antagonist of IL-1 Receptor
Authors: Quiniou Christiane , Sapieha Przemyslaw , Lahaie Isabelle , Hou Xin , Brault Sonia , Beauchamp Martin , Leduc Martin , Rihakova Lenka , Joyal Jean-Sébastien , Nadeau Sylvain , Heveker Nikolaus , Lubell William , Sennlaub Florian , Gobeil Fernand , Miller Greg , Pshezhetsky Alexey V. , Chemtob Sylvain 
Published: April 2014

Abstract
IL-1 is a major proinflammatory cytokine which interacts with the IL-1 receptor I (IL-1RI) complex, composed of IL-1RI and IL-1R accessory protein subunits. Currently available strategies to counter pathological IL-1 signaling rely on a recombinant IL-1 receptor antagonist, which directly competes with IL-1 for its binding site. Presently, there are no small antagonists of the IL-1RI complex. Given this void, we derived 15 peptides from loops of IL-1R accessory protein, which are putative interactive sites with the IL-1RI subunit. In this study, we substantiate the merits of one of these peptides, rytvela (we termed “101.10”), as an inhibitor of IL-1R and describe its properties consistent with those of an allosteric negative modulator. 101.10 (IC50 ≈ 1 nM) blocked human thymocyte proliferation in vitro, and demonstrated robust in vivo effects in models of hyperthermia and inflammatory bowel disease as well as topically in contact dermatitis, superior to corticosteroids and IL-1ra; 101.10 did not bind to IL-1RI deficient cells and was ineffective in vivo in IL-1RI knockout mice. Importantly, characterization of 101.10, revealed noncompetitive antagonist actions and functional selectivity by blocking certain IL-1R pathways while not affecting others. Findings describe the discovery of a potent and specific small (peptide) antagonist of IL-1RI, with properties in line with an allosteric negative modulator.
Enhancement of DNA Vaccine Potency through Coadministration of CIITA DNA with DNA Vaccines via Gene Gun
Authors: Kim Daejin , Hoory Talia , Monie Archana , Ting Jenny Pan-Yun , Hung Chien-Fu , Wu T.-C. 
Published: April 2014

Abstract
Administration of DNA vaccines via gene gun has emerged as an important form of Ag-specific immunotherapy. The MHC CIITA is a master regulator of MHC class II expression and also induces expression of class I molecules. We reasoned that the gene gun administration of CIITA DNA with DNA vaccines employing different strategies to improve MHC I and II processing could enhance DNA vaccine potency. We observed that DC-1 cells transfected with CIITA DNA lead to higher expression of MHC I and II molecules, leading to enhanced Ag presentation through the MHC I/II pathways. Furthermore, our data suggested that coadministration of DNA-encoding calreticulin (CRT) linked to human papillomavirus (HPV) 16 E6 Ag (CRT/E6) with CIITA DNA leads to enhanced E6-specific CD8+ T cell immune responses in vaccinated mice. In addition, coadministration of the combination of CRT/E6 DNA with CIITA DNA and DNA encoding the invariant chain (Ii) linked to the pan HLA-DR-reactive epitope (Ii-PADRE) further enhanced E6-specific CD8+ T cell immune responses in vaccinated mice. Treatment with the combination vaccine was also shown to enhance the antitumor effects and to prolong survival in TC-1 tumor-bearing mice. Vaccination with the combination vaccine also led to enhanced E6-specific CD8+ memory T cells and to long-term protection against TC-1 tumors and prolonged survival in vaccinated mice. Thus, our findings suggest that the combination of CIITA DNA with CRT/E6 and Ii-PADRE DNA vaccines represents a potentially effective means to combat tumors in the clinical setting.
Antigen Sensitivity of CD22-Specific Chimeric TCR Is Modulated by Target Epitope Distance from the Cell Membrane
Authors: James Scott E. , Greenberg Philip D. , Jensen Michael C. , Lin Yukang , Wang Jinjuan , Till Brian G. , Raubitschek Andrew A. , Forman Stephen J. , Press Oliver W. 
Published: April 2014

AbstractWe have targeted CD22 as a novel tumor-associated Ag for recognition by human CTL genetically modified to express chimeric TCR (cTCR) recognizing this surface molecule. CD22-specific cTCR targeting different epitopes of the CD22 molecule promoted efficient lysis of target cells expressing high levels of CD22 with a maximum lytic potential that appeared to decrease as the distance of the target epitope from the target cell membrane increased. Targeting membrane-distal CD22 epitopes with cTCR+ CTL revealed defects in both degranulation and lytic granule targeting. CD22-specific cTCR+ CTL exhibited lower levels of maximum lysis and lower Ag sensitivity than CTL targeting CD20, which has a shorter extracellular domain than CD22. This diminished sensitivity was not a result of reduced avidity of Ag engagement, but instead reflected weaker signaling per triggered cTCR molecule when targeting membrane-distal epitopes of CD22. Both of these parameters were restored by targeting a ligand expressing the same epitope, but constructed as a truncated CD22 molecule to approximate the length of a TCR:peptide-MHC complex. The reduced sensitivity of CD22-specific cTCR+ CTL for Ag-induced triggering of effector functions has potential therapeutic applications, because such cells selectively lysed B cell lymphoma lines expressing high levels of CD22, but demonstrated minimal activity against autologous normal B cells, which express lower levels of CD22. Thus, our results demonstrate that cTCR signal strength, and consequently Ag sensitivity, can be modulated by differential choice of target epitopes with respect to distance from the cell membrane, allowing discrimination between targets with disparate Ag density.
H2E-Derived Eα52-68 Peptide Presented by H2Ab Interferes with Clonal Deletion of Autoreactive T Cells in Autoimmune Thyroiditis
Authors: Brown Nicholas K. , McCormick Daniel J. , David Chella S. , Kong Yi-chi M. 
Published: April 2014

Abstract
Susceptibility and resistance to experimental autoimmune thyroiditis is encoded by MHC H2A genes. We reported that traditionally resistant B10 (H2b) mice permit thyroiditis induction with mouse thyroglobulin (mTg) after depleting regulatory T cells (Tregs), supporting Ab presentation to thyroiditogenic T cells. Yet, Eak transgenic mice, expressing Ab and normally absent Eb molecules (E+B10 mice), are susceptible to thyroiditis induction without Treg depletion. To explore the effect of Eb expression on mTg presentation by Ab, seven putative Ab-binding, 15–16-mer peptides were synthesized. Five were immunogenic for both B10 and E+B10 mice. The effect of Eb expression was tested by competition with an Eα52-68 peptide, because Eα52-68 occupies ∼15% of Ab molecules in E+B10 mice, binding with high affinity. Eα52-68 competitively reduced the proliferative response to mTg, mTg1677, and mTg2342 of lymph node cells primed to each Ag. Moreover, mTg1677 induced mild thyroiditis in Treg-depleted B10 mice, and in E+B10 mice without the need for Treg depletion. Eα52-68 competition with mTg-derived peptides may impede clonal deletion of pathogenic, mTg-specific T cells in the thymus.