bluuebunny/crossref_metadata_2025_split huggingface dataset:
Depletion of CD4+ T Cells Precipitates Immunopathology in Immunodeficient Mice Infected with a Noncytocidal Virus
Authors: Christensen Jan Pravsgaard , Bartholdy Christina , Wodarz Dominik , Thomsen Allan Randrup 
Published: April 2014

AbstractIFN-γ-deficient (IFN-γ−/−) mice inoculated with intermediate doses of a slowly replicating strain of lymphocytic choriomeningitis virus become chronically infected. In such mice a hypercompensated CTL response is observed that partially controls virus replication. Here we have investigated whether CD4+ Th cells are required to establish and maintain this new equilibrium. The absence of IFN-γ does not impair the generation of IL-2-producing CD4+ cells, and depletion of these cells precipitates severe CD8+ T cell-mediated immunopathology in IFN-γ−/− mice, indicating an important role of CD4+ T cells in preventing this syndrome. Analysis of organ virus levels revealed a further impairment of virus control in IFN-γ−/− mice following CD4+ cell depletion. Initially the antiviral CTL response did not require CD4+ cells, but with time an impaired reactivity toward especially the glycoprotein 33–41 epitope was noted. Enumeration of epitope-specific (glycoprotein 33–41 and nucleoprotein 396–404) CD8+ T cells by use of tetramers gave similar results. Finally, limiting dilution analysis of CTL precursors reveal an impaired capacity to sustain this population in CD4+-depleted mice, especially in mice also deficient in IFN-γ. Thus, our findings disclose that T cell help is required to sustain the expanded CTL precursor pool required in IFN-γ−/− mice. This interpretation is supported by mathematical modeling that predicts an increased requirement for help in IFN-γ−/− hosts similar to what is found with fast replicating virus strains in normal hosts. Thus, the functional integrity of CD8+ effector T cells is one important factor influencing the requirement for T cell help during viral infection.
Mycobacterium tuberculosis Phagosomes Exhibit Altered Calmodulin-Dependent Signal Transduction: Contribution to Inhibition of Phagosome-Lysosome Fusion and Intracellular Survival in Human Macrophages
Authors: Malik Zulfiqar A. , Iyer Shankar S. , Kusner David J. 
Published: April 2014

Abstract
Mycobacterium tuberculosis successfully parasitizes macrophages by disrupting the maturation of its phagosome, creating an intracellular compartment with endosomal rather than lysosomal characteristics. We have recently demonstrated that live M. tuberculosis infect human macrophages in the absence of an increase in cytosolic Ca2+ ([Ca2+]c), which correlates with inhibition of phagosome-lysosome fusion and intracellular viability. In contrast, killed M. tuberculosis induces an elevation in [Ca2+]c that is coupled to phagosome-lysosome fusion. We tested the hypothesis that defective activation of the Ca2+-dependent effector proteins calmodulin (CaM) and CaM-dependent protein kinase II (CaMKII) contributes to the intracellular pathogenesis of tuberculosis. Phagosomes containing live M. tuberculosis exhibited decreased levels of CaM and the activated form of CaMKII compared with phagosomes encompassing killed tubercle bacilli. Furthermore, ionophore-induced elevations in [Ca2+]c resulted in recruitment of CaM and activation of CaMKII on phagosomes containing live M. tuberculosis. Specific inhibitors of CaM or CaMKII blocked Ca2+ ionophore-induced phagosomal maturation and enhanced the bacilli’s intracellular viability. These results demonstrate a novel role for CaM and CaMKII in the regulation of phagosome-lysosome fusion and suggest that defective activation of these Ca2+-activated signaling components contributes to the successful parasitism of human macrophages by M. tuberculosis.
Organ-Specific Regulation of the CD8 T Cell Response toListeria monocytogenesInfection
Authors: Pope Constance , Kim Sung-Kwon , Marzo Amanda , Williams Kristina , Jiang Jiu , Shen Hao , Lefrançois Leo 
Published: April 2014

AbstractThe intestinal mucosal CD8 T cell response to infection with Listeria monocytogenes was measured using MHC class I tetramers and was compared with the response in peripheral blood, secondary lymphoid tissue, and liver. To assess the vaccination potential of Listeria and to analyze responses in C57BL/6 mouse strains, a recombinant Listeria expressing OVA (rLM-ova) was generated. The response peaked at 9 days postinfection with a much larger fraction of the intestinal mucosa and liver CD8 T cell pool OVA specific, as compared with the spleen. However, these differences were not linked to bacterial titers in each site. The higher responses in lamina propria and liver resulted in a larger CD8 memory population in these tissues. Furthermore, the level of memory induced was dependent on infectious dose and inversely correlated with the magnitude of the recall response after oral challenge. Recall responses in the tissues were most robust in the lamina propria and liver, and reactivated Ag-specific T cells produced IFN-γ. Infection of CD40- or MHC class II-deficient mice induced poor CD8 T cell responses in the intestinal mucosa, but only partially reduced responses in the spleen and liver. Overall, the results point to novel pathways of tissue-specific regulation of primary and memory antimicrobial CD8 T cell responses.
General Suppression of Macrophage Gene Expression DuringLeishmania donovaniInfection
Authors: Buates Sureemas , Matlashewski Greg 
Published: April 2014

AbstractWithin the mammalian host, Leishmania donovani is an obligatory intracellular protozoan that resides and multiplies exclusively in the phagolysosomes of macrophages. The outcome of this infection is governed by the interaction between Leishmania and macrophage molecules that ultimately effect the expression of genes within both cells. To explore the effect of this intracellular infection on macrophage gene expression, a cDNA expression array analysis was performed to compare gene expression profiles in noninfected and L. donovani-infected macrophages. In this manner, it was possible to examine the effect of infection on the expression of several hundred well-characterized host cell genes in an unbiased manner. Interestingly, ∼40% of the genes whose expression was detected in macrophages were down-regulated during infection with L. donovani. However, several genes were also induced during the infection process, some of which could play a role in recruitment of additional macrophages to the site of infection. Taken together, the general suppression of gene expression in addition to the selective induction of key genes is likely to play an important role in allowing the parasite to survive and proliferate within its host macrophage cell.
Requirement of Mitogen-Activated Protein Kinases and IκB Phosphorylation for Induction of Proinflammatory Cytokines Synthesis by Macrophages Indicates Functional Similarity of Receptors Triggered by Glycosylphosphatidylinositol Anchors from Parasitic Protozoa and Bacterial Lipopolysaccharide
Authors: Ropert Catherine , Almeida Igor C. , Closel Meire , Travassos Luiz R. , Ferguson Michael A. J. , Cohen Philip , Gazzinelli Ricardo T. 
Published: April 2014

AbstractIn the present study, we evaluated the ability of GPI-anchored mucin-like glycoproteins purified from Trypanosoma cruzi trypomastigotes (tGPI-mucin) to trigger phosphorylation of different mitogen-activated protein kinases (MAPKs) and related transcription factors in inflammatory macrophages. Kinetic experiments show that the peak of extracellular signal-related kinase (ERK)-1/ERK-2, stress-activated protein kinase (SAPK) kinase-1/mitogen-activated protein kinase (MAPK) kinase-4, and p38/SAPK-2, phosphorylation occurs between 15 and 30 min after macrophage stimulation with tGPI-mucin or GPI anchors highly purified from tGPI-mucins (tGPI). The use of the specific inhibitors of ERK-1/ERK-2 (PD 98059) and p38/SAPK-2 (SB 203580) phosphorylation also indicates the role of MAPKs, with possible involvement of cAMP response element binding protein, in triggering TNF-α and IL-12 synthesis by IFN-γ-primed-macrophages exposed to tGPI or tGPI-mucin. In addition, tGPI-mucin and tGPI were able to induce phosphorylation of IκB, and the use of SN50 peptide, an inhibitor of NF-κB translocation, resulted in 70% of TNF-α synthesis by macrophages exposed to tGPI-mucin. Finally, the similarity of patterns of MAPK and IκB phosphorylation, the concentration of drugs required to inhibit cytokine synthesis, as well as cross-tolerization exhibited by macrophages exposed to tGPI, tGPI-mucin, or bacterial LPS, suggest that receptors with the same functional properties are triggered by these different microbial glycoconjugates.
Intranasal Immunization with CpG Oligodeoxynucleotides as an Adjuvant Dramatically Increases IgA and Protection Against Herpes Simplex Virus-2 in the Genital Tract
Authors: Gallichan W. Scott , Woolstencroft Robert N. , Guarasci Tina , McCluskie Michael J. , Davis Heather L. , Rosenthal Kenneth L. 
Published: April 2014

AbstractDevelopment of vaccines capable of preventing the transmission or limiting the severity of sexually transmitted viruses, such as HSV and HIV, will likely be dependent on the induction of potent long-lasting mucosal immune responses in the genital tract. Recently, synthetic oligodeoxynucleotides (ODN) containing immunostimulatory CpG motifs were shown to serve as potent adjuvants for the induction of mucosal immune responses. Here, we show that intranasal immunization with CpG ODN, plus recombinant glycoprotein B (rgB) of HSV-1, results in significantly elevated levels of specific anti-gB IgA Abs in vaginal washes that remained high throughout the estrous cycle. Additionally, dramatically elevated numbers of specific IgA Ab-secreting cells were present and persisted in the genital tract in response to intravaginal (IVAG) HSV-2 challenge. HSV-2-specific CTL were observed at moderate levels in the spleens of CpG or non-CpG ODN-immunized mice. In contrast, strong CTL responses were observed locally in the genital tissues of both groups following IVAG HSV-2 challenge. Interestingly, mice immunized intranasally with rgB plus CpG ODN, but not non-CpG ODN, were significantly protected following IVAG HSV-2 challenge. Measurement of virus in protected CpG-immunized mice revealed a log lower level of replication within the first few days after infection. In conclusion, these results indicate that intranasal immunization with CpG ODN plus protein mediates immunity in the female genital tract capable of protecting against a sexually transmitted pathogen.
Fas/Fas Ligand Pathway, Apoptosis, and Clonal Anergy Involved in Systemic Acetylcholine Receptor T Cell Epitope Tolerance
Authors: Deng Caishu , Goluszko Elzbieta , Christadoss Premkumar 
Published: April 2014

AbstractThe cellular mechanisms of high dose systemic acetylcholine receptor (AChR) T cell epitope, α146–162 peptide-induced tolerance in experimental myasthenia gravis were examined. CD4 cells are the prime target for α146–162 peptide-induced tolerance. The expression of CD69, Fas, and B7.2 molecules on AChR-immune lymphocytes was enhanced within 4–12 h after tolerance induction. A high dose of α146–162 peptide in IFA failed to suppress T cell proliferation and/or clinical myasthenia gravis in lpr and gld mice deficient in Fas and Fas ligand, respectively. A high dose of α146–162 peptide in IFA in AChR-immunized mice induced apoptosis of BV6 cells. Further, reconstitution of IL-2 in vitro-recovered α146–162 peptide tolerized T cell proliferation, IFN-γ, and IL-10 production. The findings implicate the possible role of Fas-/Fas ligand-mediated apoptosis and the resulting clonal anergy as the mechanisms of high dose AChR α146–162 peptide-induced tolerance on CD4 cells.
Promotion of Neutrophil Apoptosis by TNF-α
Authors: Salamone Gabriela , Giordano Mirta , Trevani Analía S. , Gamberale Romina , Vermeulen Mónica , Schettinni Jorge , Geffner Jorge R. 
Published: April 2014

AbstractWe examined the ability of TNF-α to modulate human neutrophil apoptosis. Neutrophils cultured with TNF-α alone undergo a low but significant increase in the number of apoptotic cells. More interestingly, when neutrophils were pretreated with TNF-α for 1–2 min at 37°C and then were exposed to a variety of agents such as immobilized IgG, IgG-coated erythrocytes, complement-treated erythrocytes, zymosan, PMA, zymosan-activated serum, fMLP, Escherichia coli, and GM-CSF for 3 h at 37°C, a marked stimulation of apoptosis was observed. Similar results were obtained in neutrophils pretreated with TNF-α for 30 min, 1 h, 3 h, and 18 h. Dose-dependent studies showed that TNF-α enhances neutrophil apoptosis at concentrations ranging from 1 to 100 ng/ml. In contrast to the observations made in neutrophils pretreated with TNF-α, there was no stimulation of apoptosis when TNF-α was added to neutrophils previously activated by conventional agonists. Experiments performed to establish the mechanism through which TNF-α promotes neutrophil apoptosis showed that neither reactive oxygen intermediates nor the Fas/Fas ligand system appear to be involved. Our results suggest that TNF-α plays a critical role in the control of neutrophil survival by virtue of its ability to induce an apoptotic death program which could be triggered by a variety of conventional agonists.
Differential Effects of CD18, CD29, and CD49 Integrin Subunit Inhibition on Neutrophil Migration in Pulmonary Inflammation
Authors: Ridger Victoria C. , Wagner Bart E. , Wallace William A. H. , Hellewell Paul G. 
Published: April 2014

AbstractNeutrophil migration to lung alveoli is a characteristic of lung diseases and is thought to occur primarily via capillaries rather than postcapillary venules. The role of adhesion molecules CD18 and CD29 on this migration in a mouse model of lung inflammation has been investigated. The number of neutrophils present in bronchoalveolar lavage fluid was determined 4 h after intratracheal instillation of LPS (0.1–1 μg) or murine recombinant KC (CXC chemokine, 0.03–0.3 μg). Both stimuli produced a dose-related increase in neutrophil accumulation. Intravenous anti-mouse CD18 mAb, 2E6 (0.5 mg/mouse), significantly (p &lt; 0.001) attenuated LPS (0.3 μg)- but not KC (0.3 μg)-induced neutrophil accumulation. The anti-mouse CD29 mAb, HMβ1-1 (0.02 mg/mouse), significantly (p &lt; 0.05) inhibited both LPS (0.3 μg)- and KC (0.3 μg)-induced neutrophil migration. A second mAb to CD18 (GAME-46) and both F(ab′)2 and Fab of HMβ1-1 produced similar results to those above, while coadministration of mAbs did not result in greater inhibition. Electron microscopy studies showed that CD29 was involved in the movement of neutrophils from the interstitium into alveoli. The effect of mAbs to CD49 (α integrin) subunits of CD29 was also examined. mAbs to CD49e and CD49f inhibited both responses, while anti-CD49b and CD49d significantly inhibited responses to KC only. These data suggest that CD29 plays a critical role in neutrophil migration in pulmonary inflammation and that CD49b and CD49d mediate CD18-independent neutrophil accumulation.
Effective Treatment of Established Murine Collagen-Induced Arthritis by Systemic Administration of Dendritic Cells Genetically Modified to Express IL-4
Authors: Kim Seon Hee , Kim Sunyoung , Evans Christopher H. , Ghivizzani Steven C. , Oligino Thomas , Robbins Paul D. 
Published: April 2014

AbstractDendritic cells (DC) are APCs that are able to stimulate or inhibit immune responses, depending on levels of expression of MHC class I and II costimulatory molecules and cytokines. Our previous studies have suggested that the observed contralateral effect, where injection of a vector carrying certain immunomodulatory genes into one joint resulted in inhibition of arthritis in untreated joints, is mediated by in vivo modification of DC. Therefore, we have examined the ability of genetically modified DC to suppress established murine collagen-induced arthritis (CIA) after i.v. delivery. IL-4 has been shown to partially reduce the severity of CIA after repeated injection of recombinant protein or by injection of an adenoviral vector expressing IL-4. Here we demonstrate that i.v. injection of immature DC, infected with an adenoviral vector expressing IL-4, into mice with established CIA resulted in almost complete suppression of disease, with no recurrence for up to 4 wk posttreatment. Injection i.v. of fluorescently labeled DC demonstrated that the cells rapidly migrated to the liver and spleen after 6 h and to the lymph nodes by 24 h. In culture, spleen cells from DC/IL-4-treated mice produced less IFN-γ after stimulation by collagen than did control groups. In addition, DC/IL-4 administration decreased the level of specific Abs against type II collagen, in particular the IgG2 Th1 isotype 14 days posttreatment. These results demonstrate the ability to treat effectively established murine arthritis by systemic administration of DC expressing IL-4.
Extracellular Signal-Regulated Kinase 1/2-Mediated Phosphorylation of Cytosolic Phospholipase A2 Is Essential for Human Eosinophil Adhesion to Fibronectin
Authors: Sano Hiroyuki , Zhu Xiangdong , Sano Akiko , Boetticher Evan E. , Shioya Takanobu , Jacobs Benjamin , Munoz Nilda M. , Leff Alan R. 
Published: April 2014

AbstractWe examined the role of p38, p42, and p44 mitogen-activated protein kinase (MAPK) isoforms and cytosolic phospholipase A2 (cPLA2) activation in human eosinophil adhesion to plate-coated fibronectin (FN). In the control state, eosinophil adhesion was maximal, with 10 μg/ml FN at 30 min, and decreased after 60–90 min. Western blot analysis demonstrated that p44/42 MAPK (extracellular signal-regulated kinase (ERK)1/2) and cPLA2 were phosphorylated during adhesion to FN, whereas p38 MAPK phosphorylation was unchanged. Preincubation of eosinophils with U0126 or PD98059, two structurally unrelated MAPK kinase inhibitors, or arachidonic trifluoromethyl ketone, a cPLA2 inhibitor, blocked eosinophil adhesion to FN. By contrast, eosinophil adhesion was unaffected by SB203580, a p38 MAPK inhibitor. Pretreatment of eosinophils with okadaic acid, a serine/threonine phosphatase inhibitor, at the concentrations that induced ERK1/2 and cPLA2 phosphorylation caused an increase in maximal eosinophil adhesion to FN for &gt;60 min. MAPK kinase inhibition but not p38 inhibition also blocked FN-mediated F-actin redistribution in eosinophils and prevented cPLA2 phosphorylation caused by adhesion to FN. These results demonstrate that ERK1/2 mediating cPLA2 activation is essential for eosinophil adhesion to FN.
Oral Administration of Recombinant Cholera Toxin Subunit B Inhibits IL-12-Mediated Murine Experimental (Trinitrobenzene Sulfonic Acid) Colitis
Authors: Boirivant Monica , Fuss Ivan J. , Ferroni Lucietta , De Pascale Mariateresa , Strober Warren 
Published: April 2014

AbstractTrinitrobenzene sulfonic acid (TNBS)-induced colitis is an IL-12-driven, Th1 T cell-mediated colitis that resembles human Crohn’s disease. In the present study, we showed initially that the oral administration of recombinant subunit B of cholera toxin (rCT-B) at the time of TNBS-induced colitis by intrarectal TNBS instillation inhibits the development of colitis or, at later time when TNBS-induced colitis is well established, brings about resolution of the colitis. Dose-response studies showed that a majority of mice (68%) treated with rCT-B at a dose of 100 μg (times four daily doses) exhibited complete inhibition of the development of colitis, whereas a minority (30%) treated with rCT-B at a dose of 10 μg (times four daily doses) exhibited complete inhibition; in both cases, however, the remaining mice exhibited some reduction in the severity of inflammation. In further studies, we showed that rCT-B administration is accompanied by prevention/reversal of increased IFN-γ secretion (the hallmark of a Th1 response) without at the same time causing an increase in IL-4 secretion. This decreased IFN-γ secretion was not associated with the up-regulation of the secretion of counterregulatory cytokines (IL-10 or TGF-β), but was associated with a marked inhibition of IL-12 secretion, i.e., the secretion of the cytokine driving the Th1 response. Finally, we showed that rCT-B administration results in increased apoptosis of lamina propria cells, an effect previously shown to be indicative of IL-12 deprivation. From these studies, rCT-B emerges as a powerful inhibitor of Th1 T cell-driven inflammation that can conceivably be applied to the treatment of Crohn’s disease.
Role of Nitric Oxide Synthase Type 2 in Acute Infection with Murine Cytomegalovirus
Authors: Noda Satoshi , Tanaka Kazuo , Sawamura Sada-aki , Sasaki Masafumi , Matsumoto Takako , Mikami Katsunaka , Aiba Yuji , Hasegawa Hideaki , Kawabe Noboru , Koga Yasuhiro 
Published: April 2014

AbstractWhether or not NO plays a critical role in murine CMV (MCMV) infection has yet to be elucidated. In this study, we examined the role of NO in acute infection with MCMV using NO synthase type 2 (NOS2)-deficient mice. NOS2−/− mice were more susceptible to lethal infection with MCMV than NOS2+/+ mice and generated a much higher peak virus titer in the salivary gland after acute infection. A moderate increase in the MCMV titer was also observed in other organs of NOS2−/− mice such as the spleen, lung, and liver. The immune responses to MCMV infection including NK cell cytotoxicity and CTL response in NOS2−/− mice were comparable with those of NOS2+/+ mice. Moreover, the ability to produce IFN-γ is not impaired in NOS2−/− mice after MCMV infection. The peritoneal macrophages from NOS2−/− mice, however, exhibited a lower antiviral activity than those from NOS2+/+ mice, resulting in an enhanced viral replication in macrophages themselves. Treatment of these cells from NOS2+/+ mice with a selective NOS2 inhibitor decreased the antiviral activity to a level below that obtained with NOS2−/− mice. In addition, the absence of NOS2 and NOS2-mediated antiviral activity of macrophages resulted in not only an enhanced MCMV replication and a high mortality but also a consequent risk of the latency. It was thus concluded that the NOS2-mediated antiviral activity of macrophages via NO plays a protective role against MCMV infection at an early and late stage of the infection.
IL-13-Induced Airway Hyperreactivity During Respiratory Syncytial Virus Infection Is STAT6 Dependent
Authors: Tekkanat Kim K. , Maassab Hunein F. , Cho David S. , Lai Joyce J. , John Alison , Berlin Aaron , Kaplan Mark H. , Lukacs Nicholas W. 
Published: April 2014

AbstractAirway damage and hyperreactivity induced during respiratory syncytial virus (RSV) infection can have a prolonged effect in infants and young children. These infections can alter the long-term function of the lung and may lead to severe asthma-like responses. In these studies, the role of IL-13 in inducing and maintaining a prolonged airway hyperreactivity response was examined using a mouse model of primary RSV infection. Using this model, there was evidence of significant airway epithelial cell damage and sloughing, along with mucus production. The airway hyperreactivity response was significantly increased by 8 days postinfection, peaked during days 10–12, and began to resolve by day 14. When the local production of Th1- and Th2-associated cytokines was examined, there was a significant increase, primarily in IL-13, as the viral response progressed. Treatment of RSV-infected mice with anti-IL-13 substantially inhibited airway hyperreactivity. Anti-IL-4 treatment had no effect on the RSV-induced responses. Interestingly, when IL-13 was neutralized, an early increase in IL-12 production was observed within the lungs, as was a significantly lower level of viral Ags, suggesting that IL-13 may be regulating an important antiviral pathway. The examination of RSV-induced airway hyperreactivity in STAT6−/− mice demonstrated a significant attenuation of the response, similar to the anti-IL-13 treatment. In addition, STAT6−/− mice had a significant alteration of mucus-producing cells in the airway. Altogether, these studies suggest that a primary factor leading to chronic RSV-induced airway dysfunction may be the inappropriate production of IL-13.