bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cercarial Dermatitis Caused by Bird Schistosomes Comprises Both Immediate and Late Phase Cutaneous Hypersensitivity Reactions
Authors: Kouřilová Pavlína , Hogg Karen G. , Kolářová Libuše , Mountford Adrian P. 
Published: April 2014

Abstract
Avian schistosomes are the primary causative agent of cercarial dermatitis in humans, but despite its worldwide occurrence, little is known of the immune mechanism of this disease. Using a murine model, hosts were exposed to primary (1×) and multiple (4×) infections of Trichobilharzia regenti via the pinna. Penetration of larvae into the skin evoked immediate edema, thickening of the exposure site, and an influx of leukocytes, including neutrophils, macrophages, CD4+ lymphocytes, and mast cells. A large proportion of the latter were in the process of degranulating. After 1× infection, inflammation was accompanied by the release of IL-1β, IL-6, and IL-12p40. In contrast, in 4× reinfected animals the production of histamine, IL-4, and IL-10 was dramatically elevated within 1 h of infection. Analysis of Ag-stimulated lymphocytes from the skin-draining lymph nodes revealed that cells from 1× infected mice produced a mixed Th1/Th2 cytokine response, including abundant IFN-γ, whereas cells from 4× reinfected mice were Th2 polarized, dominated by IL-4 and IL-5. Serum Abs confirmed this polarization, with elevated levels of IgG1 and IgE after multiple infections. Infection with radiolabeled cercariae revealed that almost 90% of larvae remained in the skin, and the majority died within 8 days after infection, although parasites were cleared more rapidly in 4× reinfected mice. Our results are the first demonstration that cercarial dermatitis, caused by bird schistosomes, is characterized by an early type I hypersensitivity reaction and a late phase of cutaneous inflammation, both associated with a polarized Th2-type acquired immune response.
IL-4 and IL-13 Up-Regulate Intestinal Trefoil Factor Expression: Requirement for STAT6 and De Novo Protein Synthesis
Authors: Blanchard Carine , Durual Stéphane , Estienne Monique , Bouzakri Karim , Heim Markus H. , Blin Nikolaus , Cuber Jean-Claude 
Published: April 2014

AbstractThe development of intestinal goblet cell hyperplasia/hypertrophy during nematode infection involves the Th2 cytokines IL-4 and IL-13 via STAT6 activation. This is thought to play an important role in host protective immunity against the infection. In this study we demonstrate that IL-4 and IL-13 up-regulate the specific goblet cell product trefoil factor-3 (TFF3) from the mucus-producing HT-29 CL.16E and HT-29 cells selected by adaptation to methotrexate. Up-regulation of TFF3 mRNA and protein levels occurred in a time- and dose-dependent fashion and was accompanied by up-regulation of the goblet cell product mucin 2 (MUC2). Addition of actinomycin D before IL-4/IL-13 stimulation led to decreases in TFF3 mRNA levels similar to those observed in controls without IL-4/IL-13. Furthermore, IL-4-mediated increased TFF3 transcription required de novo protein synthesis. Stable transfection of HT-29 CL.16E cells with a truncated dominant-negative form of STAT6 produced a cell line that was unresponsive to IL-4/IL-13. Although only one consensus STAT6 binding site is contained in the TFF3 gene, located in the intron 1, it did not operate as an enhancer in the context of an SV40 promoter/luciferase construct. Thus, STAT6 activation mediates a transcriptional enhancement of TFF3 by induction of de novo synthesized protein in goblet cells.
Mannose-Binding Lectin Binds to Two Major Outer Membrane Proteins, Opacity Protein and Porin, ofNeisseria meningitidis
Authors: Estabrook Michele M. , Jack Dominic L. , Klein Nigel J. , Jarvis Gary A. 
Published: April 2014

AbstractHuman mannose-binding lectin (MBL) provides a first line of defense against microorganisms by complement activation and/or opsonization in the absence of specific Ab. This serum collectin has been shown to activate complement when bound to repeating sugar moieties on several microorganisms, including encapsulated serogroup B and C meningococci, which leads to increased bacterial killing. In the present study, we sought to identify the meningococcal cell surface components to which MBL bound and to characterize such binding. Outer membrane complex containing both lipooligosaccharide (LOS) and proteins and LOS from Neisseria meningitidis were examined for MBL binding by dot blot and ELISA. MBL bound outer membrane complex but not LOS. The binding to bacteria by whole-cell ELISA did not require calcium and was not inhibited by N-acetyl-glucosamine or mannose. With the use of SDS-PAGE, immunoblot analysis, and mAbs specific for meningococcal opacity (Opa) proteins and porin proteins, we determined that MBL bound to Opa and porin protein B (porB). The N-terminal amino acid sequences of the two MBL binding proteins confirmed Opa and PorB. Purified PorB inhibited the binding of MBL to meningococci. Escherichia coli with surface-expressed gonococcal Opa bound significantly more MBL than did the control strain. The binding of human factor H to purified PorB was markedly inhibited by MBL in a dose-dependent manner. Meningococci incubated with human serum bound MBL as detected by ELISA. We conclude that MBL binds to meningococci by a novel target recognition of two nonglycosylated outer membrane proteins, Opa and PorB.
Vaccination with Phosphoglycan-Deficient Leishmania major Protects Highly Susceptible Mice from Virulent Challenge without Inducing a Strong Th1 Response
Authors: Uzonna Jude E. , Späth Gerald F. , Beverley Stephen M. , Scott Phillip 
Published: April 2014

Abstract
Long-term immunity to Leishmania may require the continued presence of parasites, but previous attempts to create attenuated parasites that persist without causing disease have had limited success. Since Leishmania major mutants that lack lipophosphoglycan and other secreted phosphoglycans, termed lpg2−, persist indefinitely in infected mice without inducing any disease, we tested their ability to provide protection to virulent L. major challenge. In response to leishmanial Ag stimulation, cells from lpg2−-infected mice produced minimal levels of IL-4 and IL-10, as well as very low levels of IFN-γ. Nevertheless, when BALB/c mice infected with lpg2− parasites were challenged with virulent L. major they were protected from disease. Thus, these findings report on attenuated parasites that may be used to induce long-term protection against leishmaniasis and indicate that the immunity induced can be maintained in the absence of a strong Th1 response.
Streptococcal M5 Protein Prevents Neutrophil Phagocytosis by Interfering with CD11b/CD18 Receptor-Mediated Association and Signaling
Authors: Weineisen Maria , Sjöbring Ulf , Fällman Maria , Andersson Tommy 
Published: April 2014

AbstractGroup A streptococci (GAS) are common human pathogens that express major surface-associated virulence factors designated M proteins. In this study, we explored directly the cellular mechanisms behind their supposed ability to prevent phagocytosis. Isolated human neutrophils killed an M-negative GAS mutant (ΔM5), but not the wild-type parent strain (M5). After 3 h, 3–4 times as many ΔM5 as M5 bacteria were associated with the neutrophils, and more ΔM5 than M5 bacteria were ingested. However, there was no statistically significant difference between ΔM5 and M5 bacteria in regard to the percentage of the neutrophil-associated bacteria that were ingested, indicating that M5 protein prevents an adhesion receptor-dependent association with neutrophils and not the phagocytic machinery per se. Different Abs against CD11b/CD18 (CR3) blocked adhesion and killing of ΔM5 bacteria, whereas the blocking of two other complement receptors, CD11c/CD18 (CR4) and CD35 (CR1), did not. The CD11b/CD18-mediated killing of ΔM5 bacteria resulted in protein tyrosine phosphorylations and Cdc42 activation. Furthermore, inhibition of CD11b/CD18 receptor engagement or tyrosine kinase activity blocked the ΔM5-induced activation of Cdc42 as well as the killing of these bacteria. We conclude that M5 protein interferes with the CD11b/CD18-dependent association between GAS and neutrophils, and thereby blocks subsequent ingestion of the bacteria.
Diesel Exhaust Particles Suppress In Vivo IFN-γ Production by Inhibiting Cytokine Effects on NK and NKT Cells
Authors: Finkelman Fred D. , Yang Mingyan , Orekhova Tatyana , Clyne Erin , Bernstein Jonathan , Whitekus Michael , Diaz-Sanchez David , Morris Suzanne C. 
Published: April 2014

Abstract
Diesel exhaust particles (DEP) have strong, selective Th2 adjuvant activity when inhaled with conventional Ags. We used a novel technique for measuring in vivo cytokine production to investigate possible mechanisms by which DEP might promote a Th2 response. Injection of DEP i.p. stimulated IL-6 secretion, but failed to increase IL-4, IL-10, or TNF-α secretion, and decreased basal levels of IFN-γ. When injected with or before LPS, DEP had little effect on the LPS-induced TNF-α responses, but partially inhibited the LPS-induced IL-10 response and strongly inhibited the LPS-induced IFN-γ response. DEP also inhibited the IFN-γ responses to IL-12, IL-12 plus IL-18, IL-2, and poly(I · C). DEP treatment had little effect on the percentages of NK and NKT cells in the spleen, but inhibited LPS-induced IFN-γ production by splenic NK and NKT cells. In contrast, DEP failed to inhibit the IFN-γ response by anti-CD3 mAb-activated NKT cells. Taken together, these observations suggest that DEP inhibit Toll-like receptor ligand-induced IFN-γ responses by interfering with cytokine signaling pathways that stimulate NK and NKT cells to produce IFN-γ. Our observations also suggest that DEP may promote a Th2 response by stimulating production of inflammatory cytokines while simultaneously inhibiting production of IFN-γ, and raise the possibility that the same mechanisms contribute to the association between DEP exposure and asthma.
Decay-Accelerating Factor Deficiency Increases Susceptibility to Dextran Sulfate Sodium-Induced Colitis: Role for Complement in Inflammatory Bowel Disease
Authors: Lin Feng , Spencer David , Hatala Denise A. , Levine Alan D. , Medof M. Edward 
Published: April 2014

AbstractDecay-accelerating factor (DAF or CD55) is expressed on colonic epithelial cells but its function in the mucosa is unknown. In humans, a proportion of DAF-deficient (Cromer INAB) patients develop inflammatory bowel disease (IBD). To evaluate how DAF deficiency may contribute to gut inflammation and thus could play a role in IBD pathogenesis, we compared the severity of dextran sulfate sodium-induced colitis in Daf1 gene-targeted and control mice. Seven days after consuming 3% dextran sulfate sodium in their drinking water, Daf1−/− mice suffered markedly greater weight loss (−24.7 ± 7.5% vs −14.2% ± 4.9%), exhibited uniformly bloody diarrhea as compared with soft stool in control mice, developed shortened colons, and had larger spleens. Histological examination of distal colons showed massively increased neutrophilic and mononuclear cell infiltration, greater epithelial cell destruction, and increased ulcerations. Cytokine production in organ cultures of colonic explants showed increased levels of IL-12 and IL-6. Fourteen days after switching back to regular water, in contrast to the Daf1+/+ controls which showed little stool abnormality, all Daf1−/− mice continued to have diarrhea. Organ culture cytokine measurements at this time point, i.e., the end of the recovery phase, showed markedly increased levels of IL-10 (6-fold), IL-12 (4-fold), and IL-6 (2-fold), as well as TNF-α (&gt;10-fold) compared with the controls. Our findings argue that, as shown for IL-10 in IL-10−/− mice and IL-2 in IL-2−/− mice, DAF control of complement additionally is important in regulating gut homeostasis and consequently its activity may participate in protecting against IBD.
Human Thy-1 (CD90) on Activated Endothelial Cells Is a Counterreceptor for the Leukocyte Integrin Mac-1 (CD11b/CD18)
Authors: Wetzel Anne , Chavakis Triantafyllos , Preissner Klaus T. , Sticherling Michael , Haustein Uwe-Frithjof , Anderegg Ulf , Saalbach Anja 
Published: April 2014

AbstractLeukocyte recruitment in response to inflammatory signals is in part governed by interactions between endothelial cell receptors belonging to the Ig superfamily and leukocyte integrins. In our previous work, the human Ig superfamily glycoprotein Thy-1 (CD90) was identified as an activation-associated cell adhesion molecule on human dermal microvascular endothelial cells. Furthermore, the interaction of Thy-1 with a corresponding ligand on monocytes and polymorphonuclear cells was shown to be involved in the adhesion of these leukocytes to activated Thy-1-expressing endothelial cells. In this study, we have identified the specific interaction between human Thy-1 and the leukocyte integrin Mac-1 (CD11b/CD18; αMβ2) both in cellular systems and in purified form. Monocytes and polymorphonuclear cells were shown to adhere to transfectants expressing human Thy-1 as well as to primary Thy-1-expressing human dermal microvascular endothelial cells. Furthermore, leukocyte adhesion to activated endothelium as well as the subsequent transendothelial migration was mediated by the interaction between Thy-1 and Mac-1. This additional pathway in leukocyte-endothelium interaction may play an important role in the regulation of leukocyte recruitment to sites of inflammation.
Expansion and Functional Relevance of High-Avidity Myelin-Specific CD4+ T Cells in Multiple Sclerosis
Authors: Bielekova Bibiana , Sung Myong-Hee , Kadom Nadja , Simon Richard , McFarland Henry , Martin Roland 
Published: April 2014

AbstractMultiple sclerosis (MS) is an autoimmune disease in which myelin-specific T cells are believed to play a crucial pathogenic role. Nevertheless, so far it has been extremely difficult to demonstrate differences in T cell reactivity to myelin Ag between MS patients and controls. We believe that by using unphysiologically high Ag concentrations previous studies have missed a highly relevant aspect of autoimmune responses, i.e., T cells recognizing Ag with high functional avidity. Therefore, we focused on the characterization of high-avidity myelin-specific CD4+ T cells in a large cohort of MS patients and controls that was matched demographically and with respect to expression of MHC class II alleles. We demonstrated that their frequency is significantly higher in MS patients while the numbers of control T cells specific for influenza hemagglutinin are virtually identical between the two cohorts; that high-avidity T cells are enriched for previously in vivo-activated cells and are significantly skewed toward a proinflammatory phenotype. Moreover, the immunodominant epitopes that were most discriminatory between MS patients and controls differed from those described previously and were clearly biased toward epitopes with lower predicted binding affinities to HLA-DR molecules, pointing at the importance of thymic selection for the generation of the autoimmune T cell repertoire. Correlations between selected immunological parameters and magnetic resonance imaging markers indicate that the specificity and function of these cells influences phenotypic disease expression. These data have important implications for autoimmunity research and should be considered in the development of Ag-specific therapies in MS.
Targeted Bioactivity of Membrane-Anchored TNF by an Antibody-Derived TNF Fusion Protein
Authors: Bauer Stefan , Adrian Nicole , Williamson Barbara , Panousis Con , Fadle Natalie , Smerd Joanna , Fettah Ilknur , Scott Andrew M. , Pfreundschuh Michael , Renner Christoph 
Published: April 2014

Abstract
We describe the generation and characterization of a fusion protein consisting of a humanized anti-fibroblast-activating protein (anti-FAP) Ab and human TNF replacing the IgG1 CH2/CH3 Fc domain. The construct was generated by recombinant DNA technology and preserved its IgG1-derived dimeric structure with the TNF molecule linked as a dimer. Expression in CHO cells was optimized in serum-free medium under GMP conditions to achieve production levels up to 15 mg/liter. Recognition of the FAP Ag by the construct was as good as that by the parental anti-FAP Ab. TNF signaling was induce able via both TNF receptor types. When acting in solution, the Ab-linked TNF dimer exhibited a 10- to 20-fold lower activity compared with recombinant trimeric TNF. However, after binding to FAP-expressing cells, immobilized anti-FAP-TNF dimer was equivalent to membrane-anchored TNF with regard to bioactivity. Amplification of TNF-related pathways by mimicking the membrane-integrated TNF signaling was detectable in various systems, such as apoptosis induction or tissue factor production. The difference in TNF receptor type 1 and 2 signaling by the anti-FAP-TNF construct correlated well with its Ag-bound or -soluble status. Translating the approach into a xenograft animal model (BALB/c nu/nu mice), we demonstrated low toxicity with measurable antitumor efficacy for the TNF fusion protein after i.v. application. Immunohistochemical analysis of tumor sections showed restricted TNF-mediated macrophage recruitment to the targeted tissue in a time- and dose-dependent manner. These data warrant transfer of the anti-FAP-TNF immunocytokine into clinical trials for the treatment of FAP-positive tumors.
Immune Defects in 28-kDa Proteasome Activator γ-Deficient Mice
Authors: Barton Lance F. , Runnels Herbert A. , Schell Todd D. , Cho Yunjung , Gibbons Reta , Tevethia Satvir S. , Deepe George S. , Monaco John J. 
Published: April 2014

AbstractProtein complexes of the 28-kDa proteasome activator (PA28) family activate the proteasome and may alter proteasome cleavage specificity. Initial investigations have demonstrated a role for the IFN-γ-inducible PA28α/β complex in Ag processing. Although the noninducible and predominantly nuclear PA28γ complex has been implicated in affecting proteasome-dependent signaling pathways, such as control of the mitotic cell cycle, there is no previous evidence demonstrating a role for this structure in Ag processing. We therefore generated PA28γ-deficient mice and investigated their immune function. PA28γ−/− mice display a slight reduction in CD8+ T cell numbers and do not effectively clear a pulmonary fungal infection. However, T cell responses in two viral infection models appear normal in both magnitude and the hierarchy of antigenic epitopes recognized. We conclude that PA28γ−/− mice, like PA28α−/−/β−/− mice, are deficient in the processing of only specific Ags.
IL-2, Regulatory T Cells, and Tolerance
Authors: Nelson Brad H. 
Published: April 2014

Abstract
IL-2 is a potent T cell growth factor that for many years was assumed to amplify lymphocyte responses in vivo. Accordingly, IL-2 has been used clinically to enhance T cell immunity in patients with AIDS or cancer, and blocking Abs to the IL-2R are used to inhibit T cell responses against transplanted tissues. It was later shown in mice that, unexpectedly, disruption of the IL-2 pathway results in lymphoid hyperplasia and autoimmunity rather than immune deficiency, indicating that the major physiological function of IL-2 is to limit rather than enhance T cell responses. This apparent paradox has recently been resolved with the discovery that IL-2 is critical for the development and peripheral expansion of CD4+CD25+ regulatory T cells, which promote self-tolerance by suppressing T cell responses in vivo. Our new understanding of IL-2 biology prompts a re-evaluation of how best to clinically manipulate this important immunoregulatory pathway.
Cutting Edge: Innate Immune System Discriminates between RNA Containing Bacterial versus Eukaryotic Structural Features That Prime for High-Level IL-12 Secretion by Dendritic Cells
Authors: Koski Gary K. , Karikó Katalin , Xu Shuwen , Weissman Drew , Cohen Peter A. , Czerniecki Brian J. 
Published: April 2014

Abstract
RNA derived from bacterial but not eukaryotic sources, when transfected into human monocyte-derived dendritic cell precursors, induces high-level IL-12 secretion in conjunction with dendritic cell maturation stimuli. In vitro-transcribed mRNA that mimics the structure of bacterial mRNA in the lack of a long 3′-poly(A) tail likewise induces IL-12 secretion, but this property is lost upon efficient enzymatic 3′-polyadenylation. Among other tested RNAs, only polyuridylic acid induced IL-12 p70. This RNA response phenomenon appears biologically distinct from the classically defined response to dsRNA. RNA-transfected APC also polarize T cells in an IL-12-dependent manner toward the IFN-γhighIL-5 low Th1 phenotype, suggesting a link between the detection of appropriately structured RNA and the skewing of immune responses toward those best suited for controlling intracellular microbes. RNA structured to emulate bacterial patterns constitutes a novel vaccine strategy to engender polarized Th1-type immune responses.
CCR7 Directs the Migration of Thymocytes into the Thymic Medulla
Authors: Kwan Joanne , Killeen Nigel 
Published: April 2014

Abstract
Developing thymocytes migrate from the cortex to the medulla of the thymus as a consequence of positive selection. This migration is likely to be essential for tolerance because it allows the developing cells to move into an environment that is optimal for negative selection. Guidance mechanisms that draw positively selected thymocytes into the medulla have not been clarified, but several studies have implicated chemokines in the process. CCR7, the receptor for the medullary chemokines CCL19 and CCL21, is induced on thymocytes during their positive selection. In this study we show that premature expression of CCR7 repositions CD4+CD8+ double-positive cells into the medulla of transgenic mice. This repositioning of the thymocytes is accompanied by impairment of their development. The data show the involvement of CCR7 in medullary migration and emphasize the importance of proper thymocyte positioning for efficient T cell development.
Siva-1 and an Alternative Splice Form Lacking the Death Domain, Siva-2, Similarly Induce Apoptosis in T Lymphocytes via a Caspase-Dependent Mitochondrial Pathway
Authors: Py Bénédicte , Slomianny Christian , Auberger Patrick , Petit Patrice X. , Benichou Serge 
Published: April 2014

Abstract
Siva-1 is a death domain-containing proapoptotic protein identified as an intracellular ligand of CD27 and of the glucocorticoid-induced TNFR family-related gene, which are two members of the TNFR family expressed on lymphoid cells. Although Siva-1 expression is up-regulated in multiple pathological processes, little is known about the signaling pathway underlying the Siva-induced apoptosis. In this study, we investigated the mechanism of the proapoptotic activity of Siva-1 and an alternative splice form lacking the death domain of Siva-1, Siva-2, in T lymphocytes in which Siva proteins, CD27, and glucocorticoid-induced TNFR family-related gene are primarily expressed. Overexpression of Siva proteins triggers a typical apoptotic process manifested by cell shrinkage and surface exposure of phosphatidylserine, and confirmed by ultrastructural features. Siva-induced apoptosis is related to the CD27-mediated apoptotic pathway and results in activation of both initiator and effector caspases. This pathway involves a mitochondrial step evidenced by activation of Bid and cytochrome c release, and is modulated by overexpression of Bcl-2 or Bcl-xL. The determinants for Siva-induced apoptosis are not contained within the death domain found in the central part of Siva-1, but rather in both the N-terminal and C-terminal regions shared by both Siva proteins. The N-terminal region also participates in the translocation of both Siva proteins into the nuclear compartment. These results indicate that Siva-1 and Siva-2 mediate apoptosis in T lymphocytes via a caspase-dependent mitochondrial pathway that likely involves both cytoplasmic and nuclear events.