bluuebunny/crossref_metadata_2025 huggingface dataset:
Severe Acute Respiratory Syndrome and the Innate Immune Responses: Modulation of Effector Cell Function without Productive Infection
Authors: Tseng Chien-Te K. , Perrone Lucy A. , Zhu Hongbing , Makino Shinji , Peters Clarence J.
Published: April 2014

Severe acute respiratory syndrome (SARS) caused by a novel human coronavirus (CoV), designated SARS-CoV, is a highly contagious respiratory disease with the lungs as a major target. Although the exact mechanism of SARS-CoV pathogenesis remains unknown, an intense, ill-regulated local inflammatory response has been suggested as partially responsible for the devastating lung pathology. We investigated the interaction of SARS-CoV with human macrophages (Mφ) and dendritic cells (DC), two key innate immune cells of the host immune system, by focusing on their susceptibility to viral infection and subsequent responses (e.g., phenotypic maturation, T cell-priming activity, phagocytosis, and cytokine production). We found neither cell to be permissive for SARS-CoV replication. However, incubation of Mφ and DC with live, but not gamma irradiation-inactivated, viruses appeared to better sustain their viability. Also, exposure to infectious SARS-CoV led to the phenotypic and functional maturation of DC, with regard to MHC class II and costimulatory molecule expression, T cell-stimulatory capacity, and cytokine production, respectively. Cytokine production was also observed for Mφ, which were refractory to cell surface phenotypic changes. Strikingly, live SARS-CoV could further prime cell types to respond to a suboptimal dose of bacterial LPS (100 ng/ml), resulting in massive release of IL-6 and IL-12. However, the endocytic capacity (e.g., Ag capture) of Mφ was significantly compromised upon exposure to infectious SARS-CoV. This study is the first demonstration that although SARS-CoV does not productively infect human Mφ or DC, it appears to exert differential effects on Mφ and DC maturation and functions, which might contribute to SARS pathogenesis.
Mechanisms of Mucosal and Parenteral Tuberculosis Vaccinations: Adenoviral-Based Mucosal Immunization Preferentially Elicits Sustained Accumulation of Immune Protective CD4 and CD8 T Cells within the Airway Lumen
Authors: Santosuosso Michael , Zhang Xizhong , McCormick Sarah , Wang Jun , Hitt Mary , Xing Zhou
Published: April 2014

The mechanisms underlying better immune protection by mucosal vaccination have remained poorly understood. In our current study we have investigated the mechanisms by which respiratory virus-mediated mucosal vaccination provides remarkably better immune protection against pulmonary tuberculosis than parenteral vaccination. A recombinant adenovirus-based tuberculosis (TB) vaccine expressing Mycobacterium tuberculosis Ag85A (AdAg85A) was administered either intranasally (i.n.) or i.m. to mice, and Ag-specific CD4 and CD8 T cell responses, including frequency, IFN-γ production, and CTL, were examined in the spleen, lung interstitium, and airway lumen. Although i.m. immunization with AdAg85A led to activation of T cells, particularly CD8 T cells, in the spleen and, to a lesser extent, in the lung interstitium, it failed to elicit any T cell response in the airway lumen. In contrast, although i.n. immunization failed to effectively activate T cells in the spleen, it uniquely elicited higher numbers of Ag-specific CD4 and CD8 T cells in the airway lumen that were capable of IFN-γ production and cytolytic activities, as assessed by an intratracheal in vivo CTL assay. These airway luminal T cells of i.n. immunized mice or splenic T cells of i.m. immunized mice, upon transfer locally to the lungs of naive SCID mice, conferred immune protection against M. tuberculosis challenge. Our study has demonstrated that the airway luminal T cell population plays an important role in immune protection against pulmonary TB, thus providing mechanistic insights into the superior immune protection conferred by respiratory mucosal TB vaccination.
Neisseria gonorrhoeaeEnhances Infection of Dendritic Cells by HIV Type 1
Authors: Zhang Jizhong , Li Geling , Bafica Andre , Pantelic Milica , Zhang Pei , Broxmeyer Hal , Liu Ying , Wetzler Lee , He Johnny J. , Chen Tie
Published: April 2014

Clinical studies indicate that Neisseria gonorrhoeae (gonococci (GC)) has the capacity to enhance HIV type 1 (HIV-1) infection. We studied whether GC enhances HIV infection of activated dendritic cells (DCs). The results show that GC can dramatically enhance HIV replication in human DCs during coinfection. The GC component responsible for HIV infection enhancement may be peptidoglycan, which activates TLR2. TLR2 involvement is suggested by bacterial lipoprotein, a TLR2-specific inducer, which stimulates a strong enhancement of HIV infection by human DCs. Moreover, participation of TLR2 is further implicated because GC is unable to stimulate expression of HIV in DCs of TLR2-deficient HIV-1-transgenic mice. These results provide one potential mechanism through which GC infection increases HIV replication in patients infected with both GC and HIV.
Deficiency of Dermcidin-Derived Antimicrobial Peptides in Sweat of Patients with Atopic Dermatitis Correlates with an Impaired Innate Defense of Human Skin In Vivo
Authors: Rieg Siegbert , Steffen Heiko , Seeber Silke , Humeny Andreas , Kalbacher Hubert , Dietz Klaus , Garbe Claus , Schittek Birgit
Published: April 2014

Antimicrobial peptides are an integral part of the epithelial innate defense system. Dermcidin (DCD) is a recently discovered antimicrobial peptide with a broad spectrum of activity. It is constitutively expressed in human eccrine sweat glands and secreted into sweat. Patients with atopic dermatitis (AD) have recurrent bacterial or viral skin infections and pronounced colonization with Staphylococcus aureus. We hypothesized that patients with AD have a reduced amount of DCD peptides in sweat contributing to the compromised constitutive innate skin defense. Therefore, we performed semiquantitative and quantitative analyses of DCD peptides in sweat of AD patients and healthy subjects using surface-enhanced laser desorption ionization time-of-flight mass spectrometry and ELISA. The data indicate that the amount of several DCD-derived peptides in sweat of patients with AD is significantly reduced. Furthermore, compared with atopic patients without previous infectious complications, AD patients with a history of bacterial and viral skin infections were found to have significantly less DCD-1 and DCD-1L in their sweat. To analyze whether the reduced amount of DCD in sweat of AD patients correlates with a decreased innate defense, we determined the antimicrobial activity of sweat in vivo. We showed that in healthy subjects, sweating leads to a reduction of viable bacteria on the skin surface, but this does not occur in patients with AD. These data indicate that reduced expression of DCD in sweat of patients with AD may contribute to the high susceptibility of these patients to skin infections and altered skin colonization.
Phosphatidylinositol-Specific Phospholipase C of Bacillus anthracis Down-Modulates the Immune Response
Authors: Zenewicz Lauren A. , Wei Zhengyu , Goldfine Howard , Shen Hao
Published: April 2014

Phosphatidylinositol-specific phospholipases (PI-PLCs) are virulence factors produced by many pathogenic bacteria, including Bacillus anthracis and Listeria monocytogenes. Bacillus PI-PLC differs from Listeria PI-PLC in that it has strong activity for cleaving GPI-anchored proteins. Treatment of murine DCs with Bacillus, but not Listeria, PI-PLC inhibited dendritic cell (DC) activation by TLR ligands. Infection of mice with Listeria expressing B. anthracis PI-PLC resulted in a reduced Ag-specific CD4 T cell response. These data indicate that B. anthracis PI-PLC down-modulates DC function and T cell responses, possibly by cleaving GPI-anchored proteins important for TLR-mediated DC activation.
Mouse Genetic Background Is a Major Determinant of Isotype-Related Differences for Antibody-Mediated Protective Efficacy againstCryptococcus neoformans
Authors: Rivera Johanna , Casadevall Arturo
Published: April 2014

The protective efficacy of mAbs to Cryptococcus neoformans glucuronoxylomannan depends on Ab isotype. Previous studies in A/JCr and C57BL/6J mice showed relative protective efficacy of IgG1, IgG2a ≫ IgG3. However, we now report that in C57BL/6J × 129/Sv mice, IgG3 is protective while IgG1 is not protective, with neither isotype being protective in 129/Sv mice. IgG1, IgG2a, and IgG3 had different effects on IFN-γ expression in infected C57BL/6J × 129/Sv mice. IgG1-treated C57BL/6J × 129/Sv mice had significantly more pulmonary eosinophilia than IgG2a- and IgG3-treated C57BL/6J × 129/Sv mice. C. neoformans infection and Ab administration had different effects on FcγRI, FcγRII, and FcγRIII expression in C57BL/6J, 129/Sv, and C57BL/6J × 129/Sv mice. Our results indicate that the relative efficacy of Ab isotype function against C. neoformans is a function of the genetic background of the host and that IgG3-mediated protection in C57BL/6J × 129/Sv mice was associated with lower levels of IFN-γ and fewer pulmonary eosinophils. The dependence of isotype efficacy on host genetics underscores a previously unsuspected complex relationship between the cellular and humoral arms of the adaptive immune response.
Lack of Chemokine Receptor CCR5 Promotes Murine Fulminant Liver Failure by Preventing the Apoptosis of Activated CD1d-Restricted NKT Cells
Authors: Ajuebor Maureen N. , Aspinall Alex I. , Zhou Feng , Le Tai , Yang Yang , Urbanski Stefan J. , Sidobre Stéphané , Kronenberg Mitchell , Hogaboam Cory M. , Swain Mark G.
Published: April 2014

Fulminant liver failure (FLF) consists of a cascade of events beginning with a presumed uncontrolled systemic activation of the immune system. The etiology of FLF remains undefined. In this study, we demonstrate that CCR5 deficiency promotes the development of acute FLF in mice following Con A administration by preventing activated hepatic CD1d-restricted NKT cells (but not conventional T cells) from dying from activation-induced apoptosis. The resistance of CCR5-deficient NKT cells from activation-induced apoptosis following Con A administration is not due to a defective Fas-driven death pathway. Moreover, FLF in CCR5-deficient mice also correlated with hepatic CCR5-deficient NKT cells, producing more IL-4, but not IFN-γ, relative to wild-type NKT cells. Furthermore, FLF in these mice was abolished by IL-4 mAb or NK1.1 mAb treatment. We propose that CCR5 deficiency may predispose individuals to the development of FLF by preventing hepatic NKT cell apoptosis and by regulating NKT cell function, establishing a novel role for CCR5 in the development of this catastrophic liver disease that is independent of leukocyte recruitment.
Stage-Specific Expression of Surface Antigens by Toxoplasma gondii as a Mechanism to Facilitate Parasite Persistence
Authors: Kim Seon-Kyeong , Boothroyd John C.
Published: April 2014

Toxoplasma persists in the face of a functional immune system. This success critically depends on the ability of parasites to activate a strong adaptive immune response during acute infection with tachyzoites that eliminates most of the parasites and to undergo stage conversion to bradyzoites that encyst and persist predominantly in the brain. A dramatic change in antigenic composition occurs during stage conversion, such that tachyzoites and bradyzoites express closely related but antigenically distinct sets of surface Ags belonging to the surface Ag 1 (SAG1)-related sequence (SRS) family. To test the contribution of this antigenic switch to parasite persistence, we engineered parasites to constitutively express the normally bradyzoite-specific SRS9 (SRS9c) mutants and tachyzoite-specific SAG1 (SAG1c) mutants. SRS9c but not wild-type parasites elicited a SRS9-specific immune response marked by IFN-γ production, suggesting that stage-specificity of SRS Ags determines their immunogenicity in infection. The induction of a SRS9-specific immune response correlated with a continual decrease in the number of SRS9c cysts persisting in the brain. In contrast, SAG1c mutants produced reduced brain cyst loads early in chronic infection, but these substantially increased over time accompanying a hyperproduction of IFN-γ, TNF-α, and IL-10, and severe encephalitis. We conclude that stage-specific expression of SRS Ags is among the key mechanisms by which optimal parasite persistency is established and maintained.
Critical Role of Proline-Rich Tyrosine Kinase 2 in Reversion of the Adhesion-Mediated Suppression of Reactive Oxygen Species Generation by Human Neutrophils
Authors: Zhao Tieming , Bokoch Gary M.
Published: April 2014

Neutrophils act as the first line of innate immune defense against invading microorganisms during infection and inflammation. The tightly regulated production of reactive oxygen species (ROS) through activation of NADPH oxidase is a major weapon used by neutrophils and other phagocytic leukocytes to combat such pathogens. Cellular adhesion signals play important physiological roles in regulating the activation of NADPH oxidase and subsequent ROS formation. We previously showed that the initial suppression of the oxidase response of chemoattractant-stimulated adherent neutrophils is mediated via inhibition of Vav1-induced activation of the NADPH oxidase regulatory GTPase Rac2 by adhesion signals. In this study we show that prior exposure of neutrophils to a number of cytokines and inflammatory mediators, including TNF-α, GM-CSF, and platelet-activating factor, overcomes the adhesion-mediated suppression of ROS formation. Proline-rich tyrosine kinase 2 (pyk2) activity is enhanced under these conditions, correlating with the restoration of Vav1 and Rac2 activities. Both dominant negative pyk2 and a pyk2-selective inhibitor prevented restoration of ROS production induced by TNF-α, GM-CSF, and platelet-activating factor, and this loss of pyk2 activity resulted in decreased Vav1 tyrosine phosphorylation and subsequent Rac2 activation. Our studies identify pyk2 as a critical regulatory component and a molecular switch to overcome the suppression of leukocyte oxidant generation by cell adhesion. This activity constitutes a mechanism by which cytokines might lead to rapid elimination of invading pathogens by adherent neutrophils under normal conditions or enhance tissue damage in pathological states.
The Role of p38 MAPK in Rhinovirus-Induced Monocyte Chemoattractant Protein-1 Production by Monocytic-Lineage Cells
Authors: Hall David J. , Bates Mary Ellen , Guar Lasya , Cronan Mark , Korpi Nichole , Bertics Paul J.
Published: April 2014

Viral respiratory infections are a major cause of asthma exacerbations and can contribute to the pathogenesis of asthma. Major group human rhinovirus enters cells by binding to the cell surface molecule ICAM-1 that is present on epithelial and monocytic lineage cells. The focus of the resulting viral infection is in bronchial epithelia. However, previous studies of the cytokine dysregulation that follows rhinovirus infection have implicated monocytic lineage cells in establishing the inflammatory environment even though productive infection is not a result. We have determined that human alveolar macrophages and human peripheral blood monocytes release MCP-1 upon exposure to human rhinovirus 16 (HRV16). Indeed, we have found p38 MAPK activation in human alveolar macrophages within 15 min of exposure to HRV16, and this activation lasts up to 1 h. The targets of p38 MAPK activation include transcriptional activators of the MCP-1 promoter. The transcription factor ATF-2, a p38 MAPK substrate, is phosphorylated 45 min after HRV16 exposure. Furthermore, IκBα, the inhibitor of the transcription factor NF-κB, is degraded. Prevention of HRV16 binding was effective in blocking p38 MAPK activation, ATF-2 phosphorylation, and MCP-1 release. This is the first report of a relationship between HRV16 exposure, MCP-1 release and monocytic-lineage cells suggesting that MCP-1 plays a role in establishing the inflammatory microenvironment initiated in the human airway upon exposure to rhinovirus.
Involvement of SHIP in TLR2-Induced Neutrophil Activation and Acute Lung Injury
Authors: Strassheim Derek , Kim Jae-Yeol , Park Jong-Sung , Mitra Sanchayita , Abraham Edward
Published: April 2014

The SHIP converts phosphatidylinositol 3,4,5 triphosphate to phosphatidyl 3,4 biphosphate. SHIP has negative regulatory functions on PI3K-dependent signaling pathways, which occupy important roles in modulating neutrophil functions. We used neutrophils from transgenic SHIP−/− and SHIP+/+ mice that were stimulated with peptidoglycan (PGN) to examine the role of SHIP in TLR2-induced neutrophil activation. SHIP−/− neutrophils demonstrated significantly increased activation of the PI3K-dependent kinase Akt after exposure to PGN. Release of cytokines and chemokines, including TNF-α, IL-1β, IL-6, IL-10, and MIP-2, was also increased in SHIP−/− compared with SHIP+/+ neutrophils. There was no difference in the nuclear translocation of the transcriptional factor NF-κB between PGN-stimulated SHIP−/− and SHIP+/+ neutrophils. However, phosphorylation of the p65 subunit of NF-κB, an event essential for optimal transcriptional activity of NF-κB, was increased in TLR2-activated SHIP−/− neutrophils. SHIP−/− neutrophils demonstrated greater activation of ERK1/2 and p38 MAPKs than did SHIP+/+ neutrophils after exposure to PGN. The severity of acute lung injury induced by PGN was greater in SHIP−/− as compared with SHIP+/+ mice. These results demonstrate that SHIP has a negative regulatory role in TLR2-induced neutrophil activation and in the development of related in vivo neutrophil-dependent inflammatory processes, such as acute lung injury.
Monocyte Adhesion to Xenogeneic Endothelium during Laminar Flow Is Dependent on α-Gal-Mediated Monocyte Activation
Authors: Peterson Mark D. , Jin Rongyu , Hyduk Sharon , Duchesneau Pascal , Cybulsky Myron I. , Waddell Thomas K.
Published: April 2014

Monocytes are the predominant inflammatory cell recruited to xenografts and participate in delayed xenograft rejection. In contrast to allogeneic leukocytes that require up-regulation of endothelial adhesion molecules to adhere and emigrate into effector tissues, we demonstrate that human monocytes adhere rapidly to unstimulated xenogeneic endothelial cells. The major xenoantigen galactoseα(1,3)galactoseβ(1,4)GlcNAc-R (α-gal) is abundantly expressed on xenogeneic endothelium. We have identified a putative receptor for α-gal on human monocytes that is a member of the C-type family of lectin receptors. Monocyte arrest under physiological flow conditions is regulated by α-gal, because cleavage or blockade results in a dramatic reduction in monocyte adhesion. Recruitment of human monocytes to unactivated xenogeneic endothelial cells requires both α4 and β2 integrins on the monocyte; binding of α-gal to monocytes results in rapid activation of β2, but not α4, integrins. Thus, activation of monocyte β2 integrins by α-gal expressed on xenogeneic endothelium provides a mechanism that may explain the dramatic accumulation of monocytes in vivo.
Evidence for a Role of Phosphodiesterase 4 in Lipopolysaccharide-Stimulated Prostaglandin E2 Production and Matrix Metalloproteinase-9 Activity in Human Amniochorionic Membranes
Authors: Oger Stéphanie , Méhats Céline , Dallot Emmanuelle , Cabrol Dominique , Leroy Marie-Josèphe
Published: April 2014

Chorioamniotic infection is a leading cause of preterm premature rupture of fetal membranes (amnion and chorion). Bacterial infection induces an inflammatory response characterized by elevated production of proinflammatory cytokines; the latter activate the production of both PGs that stimulate uterine contractions, and matrix metalloproteinases (MMPs) that degrade the extracellular matrix of the chorioamniotic membranes. The inflammatory response is under the control of cAMP content, which is partly regulated by phosphodiesterases (PDE). In this study, we investigated the role of the PDE4 family in the inflammatory process triggered by LPS in a model of amniochorionic explants. We found that PDE4 family is the major cAMP-PDE expressed in human fetal membranes and that PDE4 activity is increased by LPS treatment. Selective inhibition of PDE4 activity affected LPS signaling, because PDE4 inhibitors (rolipram and/or cilomilast) reduced the release of the proinflammatory cytokine TNF-α and increased the release of the anti-inflammatory cytokine IL-10. PDE4 inhibition reduced cyclooxygenase-2 protein expression and PGE2 production and also modulated MMP-9, a key mediator of the membrane rupture process, by inhibiting pro-MMP-9 mRNA expression and pro-MMP-9 activity. These results demonstrate that the PDE4 family participates in the regulation of the inflammatory response associated with fetal membrane rupture during infection. The PDE4 family may be an appropriate pharmacological target for the management of infection-induced preterm delivery.
Apoptotic Pathways Are Inhibited by Leptin Receptor Activation in Neutrophils
Authors: Bruno Andreina , Conus Sébastien , Schmid Inès , Simon Hans-Uwe
Published: April 2014

Leptin regulates food intake as well as metabolic, endocrine, and immune functions. It exerts proliferative and antiapoptotic activities in a variety of cell types, including T cells. Leptin also stimulates macrophages and neutrophils, and its production is increased during inflammation. In this study, we demonstrate that human neutrophils express leptin surface receptors under in vitro and in vivo conditions, and that leptin delays apoptosis of mature neutrophils in vitro. The antiapoptotic effects of leptin were concentration dependent and blocked by an anti-leptin receptor mAb. The efficacy of leptin to block neutrophil apoptosis was similar to G-CSF. Using pharmacological inhibitors, we obtained evidence that leptin initiates a signaling cascade involving PI3K- and MAPK-dependent pathways in neutrophils. Moreover, leptin delayed the cleavage of Bid and Bax, the mitochondrial release of cytochrome c and second mitochondria-derived activator of caspase, as well as the activation of both caspase-8 and caspase-3 in these cells. Taken together, leptin is a survival cytokine for human neutrophils, a finding with potential pathologic relevance in inflammatory diseases.
IL-13 Regulates the Immune Response to Inhaled Antigens
Authors: Padilla Jocelyn , Daley Eleen , Chow Anthony , Robinson Kesha , Parthasarathi Kaushik , McKenzie Andrew N. J. , Tschernig Thomas , Kurup Viswanath P. , Donaldson Debra D. , Grunig Gabriele
Published: April 2014

The large inhibitory effect of IL-13 blockers on the asthma phenotype prompted us to ask whether IL-13 would play a role in regulating the allergic immune response in addition to its documented effects on structural pulmonary cells. Because IL-13 does not interact with murine T or B cells, but with monocytes, macrophages, and dendritic cells (DCs), we examined the role of IL-13 in the activation of pulmonary macrophages and DCs and in the priming of an immune response to a harmless, inhaled Ag. We found that a majority of cells called “alveolar or interstitial macrophages” express CD11c at high levels (CD11chigh) and are a mixture of at least two cell types as follows: 1) cells of a mixed phenotype expressing DC and macrophage markers (CD11c, CD205, and F4/80) but little MHC class II (MHC II); and 2) DC-like cells expressing CD11c, CD205, MHC II, and costimulatory molecules. Endogenous IL-13 was necessary to induce and sustain the increase in MHC II and CD40 expression by pulmonary CD11chigh cells, demonstrated by giving an IL-13 inhibitor as a measure of prevention or reversal to allergen-primed and -challenged mice. Conversely, IL-13 given by inhalation to naive mice increased the expression of MHC II and costimulatory molecules by CD11chigh cells in an IL-4Rα-dependent manner. We found that exogenous IL-13 exaggerated the immune and inflammatory responses to an inhaled, harmless Ag, whereas endogenous IL-13 was necessary for the priming of naive mice with an inhaled, harmless Ag. These data indicate that blockade of IL-13 may have therapeutic potential for controlling the immune response to inhaled Ags.
Role of Cathepsin S-Dependent Epithelial Cell Apoptosis in IFN-γ-Induced Alveolar Remodeling and Pulmonary Emphysema
Authors: Zheng Tao , Kang Min Jong , Crothers Kristina , Zhu Zhou , Liu Wei , Lee Chun Geun , Rabach Lesley A. , Chapman Harold A. , Homer Robert J. , Aldous David , DeSanctis George , Underwood Stephen , Graupe Michael , Flavell Richard A. , Schmidt John A. , Elias Jack A.
Published: April 2014

Th1/Tc1 inflammation and remodeling responses characterized by tissue atrophy and destruction frequently coexist in human diseases and disorders. However, the mechanisms that are used by Th1/Tc1 cytokines, like IFN-γ, to induce these responses have not been defined. To elucidate the mechanism(s) of IFN-γ-induced tissue remodeling and destruction, we characterized the pathway that lung-targeted, transgenic IFN-γ uses to induce alveolar remodeling in a murine pulmonary emphysema modeling system. In these mice, transgenic IFN-γ caused epithelial cell DNA injury and apoptosis detectable with TUNEL (Roche) and dual annexin V and propidium iodide staining. These responses were associated with death receptor and mitochondrial apoptosis pathway activation. Importantly, apoptosis inhibition with a caspase inhibitor (N-benzylcarboxy-Val-Ala-Asp-fluoromethyl-ketone) or a null mutation of caspase-3 blocked this DNA injury and apoptosis response and significantly ameliorated IFN-γ-induced emphysema. These interventions also ameliorated IFN-γ-induced inflammation and decreased pulmonary protease burden. Selective cathepsin S inhibition and a null mutation of cathepsin S also decreased IFN-γ-induced DNA injury, apoptosis, emphysema, inflammation, and protease accumulation. These studies demonstrate that cathepsin S-dependent epithelial cell apoptosis is a critical event in the pathogenesis of IFN-γ-induced alveolar remodeling and emphysema. They also link inflammation, protease/antiprotease alterations, and protease-dependent apoptosis in the pathogenesis of Th1/Tc1 cytokine-induced tissue remodeling and destructive responses.
Curcumin Inhibits Immunostimulatory Function of Dendritic Cells: MAPKs and Translocation of NF-κB as Potential Targets
Authors: Kim Gi-Young , Kim Ki-Hyung , Lee Soong-Hwan , Yoon Man-Soo , Lee Hee-Jeong , Moon Dong-Oh , Lee Chang-Min , Ahn Soon-Cheol , Park Young Chul , Park Yeong-Min
Published: April 2014

Curcumin has been shown to exhibit anti-inflammatory, antimutagenic, and anticarcinogenic activities. However, the effect of curcumin on the maturation and immunostimulatory function of dendritic cells (DC) largely remains unknown. In this study, we examined whether curcumin can influence surface molecule expression, cytokine production, and their underlying signaling pathways in murine bone marrow-derived DC. DC were derived from murine bone marrow cells and used as immature or LPS-stimulated mature cells. The DC were tested for surface molecule expression, cytokine production, dextran uptake, the capacity to induce T cell differentiation, and their underlying signaling pathways. Curcumin significantly suppressed CD80, CD86, and MHC class II expression, but not MHC class I expression, in the DC. The DC also exhibited impaired IL-12 expression and proinflammatory cytokine production (IL-1β, IL-6, and TNF-α). The curcumin-treated DC were highly efficient at Ag capture, via mannose receptor-mediated endocytosis. Curcumin inhibited LPS-induced MAPK activation and the translocation of NF-κB p65. In addition, the curcumin-treated DC showed an impaired induction of Th1 responses and a normal cell-mediated immune response. These novel findings provide new insight into the immunopharmacological role of curcumin in impacting on the DC. These novel findings open perspectives for the understanding of the immunopharmacological role of curcumin and therapeutic adjuvants for DC-related acute and chronic diseases.
Serum Amyloid A-Luciferase Transgenic Mice: Response to Sepsis, Acute Arthritis, and Contact Hypersensitivity and the Effects of Proteasome Inhibition
Authors: Zhang Ning , Ahsan Muhammad H. , Purchio Anthony F. , West David B.
Published: April 2014

Acute phase serum amyloid A proteins (A-SAAs) are multifunctional apolipoproteins produced in large amounts during the acute phase of an inflammation and also during the development of chronic inflammatory diseases. In this study we present a Saa1-luc transgenic mouse model in which SAA1 gene expression can be monitored by measuring luciferase activity using a noninvasive imaging system. When challenged with LPS, TNF-α, or IL-1β, in vivo imaging of Saa1-luc mice showed a 1000- to 3000-fold induction of luciferase activity in the hepatic region that peaked 4–7 h after treatment. The induction of liver luciferase expression was consistent with an increase in SAA1 mRNA in the liver and a dramatic elevation of the serum SAA1 concentration. Ex vivo analyses revealed luciferase induction in many tissues, ranging from several-fold (brain) to >5000-fold (liver) after LPS or TNF-α treatment. Pretreatment of mice with the proteasome inhibitor bortezomib significantly suppressed LPS-induced SAA1 expression. These results suggested that proteasome inhibition, perhaps through the NF-κB signaling pathway, may regulate SAA1 expression. During the development of acute arthritis triggered by intra-articular administration of zymosan, SAA1 expression was induced both locally at the knee joint and systemically in the liver, and the induction was significantly suppressed by bortezomib. Induction of SAA1 expression was also demonstrated during contact hypersensitivity induced by topical application of oxazolone. These results suggest that both local and systemic induction of A-SAA occur during inflammation and may contribute to the pathogenesis of chronic inflammatory diseases associated with amyloid deposition.
Protection of Plasminogen Activator Inhibitor-1-Deficient Mice from Nasal Allergy
Authors: Sejima Takayuki , Madoiwa Seiji , Mimuro Jun , Sugo Teruko , Okada Kiyotaka , Ueshima Shigeru , Matsuo Osamu , Ishida Takashi , Ichimura Keiichi , Sakata Yoichi
Published: April 2014

This study was performed to clarify the relationship between fibrinolytic components and the pathology of allergy, particularly that during the development of nasal allergy and nasal tissue changes. Intranasal OVA challenge after sensitization by i.p. administration of OVA induced a higher level of excess subepithelial collagen deposition in wild-type (WT) C57BL/6J mice than in plasminogen activator inhibitor (PAI)-1-deficient (PAI-1−/−) mice. The excess PAI-1 induction in the nasal mucosa and higher level of active PAI-1 in the nasal lavage fluid of WT-OVA mice compared with those in WT-control mice suggested that the decrease of proteolytic activity inhibits the removal of subepithelial collagen. The frequency of sneezing, nasal rubbing, nasal hyperresponsiveness, production of specific IgG1 and IgE in the serum, and production of IL-4 and IL-5 in splenocyte culture supernatant increased significantly in WT-OVA mice. In PAI-1−/− mice, these reactions were absent, and specific IgG2a in serum and IFN-γ in splenocyte culture medium increased significantly. Histopathologically, there were marked goblet cell hyperplasia and eosinophil infiltration into the nasal mucosa in WT-OVA mice, but these were absent in PAI-1−/− mice. These results indicate that the immune response in WT-OVA mice can be classified as a dominant Th2 response, which would promote collagen deposition. In contrast, the Th2 response in PAI-1−/− mice was down-regulated, and the immune response shifted from Th2-dominant reaction to a Th1-dominant one. Taken together, these findings suggest that PAI-1 plays an important role not only in thrombolysis but also in immune response.
IgA Antibodies Impair Resistance againstHelicobacter pyloriInfection: Studies on Immune Evasion in IL-10-Deficient Mice
Authors: Akhiani Ali A. , Stensson Anneli , Schön Karin , Lycke Nils Y.
Published: April 2014

We recently reported that Helicobacter pylori-specific Abs impair the development of gastritis and down-regulate resistance against H. pylori infection. In this study, we asked whether IgA Abs specifically can have an impact on H. pylori colonization and gastric inflammation. To obtain a sensitive model for the study of inflammation we crossed IgA- and IL-10-deficient mice. We found that IL-10−/−/IgA−/− mice were significantly less colonized than IL-10−/−/IgA+/+ mice, which in turn were less colonized than wild-type (WT) mice. The IL-10−/−/IgA−/− mice exhibited a 1.2-log reduction in bacterial counts compared with that in IL-10−/−/IgA+/+ mice, suggesting that IgA Abs rather promoted than prevented infection. The reduced colonization in IL-10−/−/IgA−/− mice was associated with the most severe gastritis observed, albeit all IL-10−/− mice demonstrated more severe gastric inflammation than wild-type mice. The gastritis score and the infiltration of CD4+ T cells into the gastric mucosa were significantly higher in IL-10−/−/IgA−/− mice than in IL-10−/−/IgA+/+ mice, arguing that IgA Abs counteracted inflammation. Moreover, following oral immunization, IL-10−/−/IgA−/− mice were significantly better protected against colonization than IL-10−/−/IgA+/+ mice. However, the stronger protection was associated with more severe postimmunization gastritis and gastric infiltration of CD4+ T cells. There was also a clear increase in complement receptor-expressing cells in IL-10−/−/IgA−/− mice, though C3b-fragment deposition in the gastric mucosa was comparable between the two. Finally, specific T cell responses to recall Ag demonstrated higher levels of IFN-γ production in IL-10−/−/IgA−/− as compared with IL-10−/−/IgA+/+ mice. Thus, it appears that IgA and IL-10 help H. pylori bacteria evade host resistance against infection.
Mannose-Containing Molecular Patterns Are Strong Inducers of Cyclooxygenase-2 Expression and Prostaglandin E2 Production in Human Macrophages
Authors: Fernández Nieves , Alonso Sara , Valera Isela , Vigo Ana González , Renedo Marta , Barbolla Luz , Crespo Mariano Sánchez
Published: April 2014

The induction of cyclooxygenase-2 (COX-2) and the production of PGE2 in response to pathogen-associated molecular patterns decorated with mannose moieties were studied in human monocytes and monocyte-derived macrophages (MDM). Saccharomyces cerevisiae mannan was a robust agonist, suggesting the involvement of the mannose receptor (MR). MR expression increased along the macrophage differentiation route, as judged from both its surface display assessed by flow cytometry and the ability of MDM to ingest mannosylated BSA. Treatment with mannose-BSA, a weak agonist of the MR containing a lower ratio of attached sugar compared with pure polysaccharides, before the addition of mannan inhibited COX-2 expression, whereas this was not observed when agonists other than mannan and zymosan were used. HeLa cells, which were found to express MR mRNA, showed a significant induction of COX-2 expression upon mannan challenge. Conversely, mannan did not induce COX-2 expression in HEK293 cells, which express the mRNA encoding Endo180, a parent receptor pertaining to the MR family, but not the MR itself. These data indicate that mannan is a strong inducer of COX-2 expression in human MDM, most likely by acting through the MR route. Because COX-2 products can be both proinflammatory and immunomodulatory, these results disclose a signaling route triggered by mannose-decorated pathogen-associated molecular patterns, which can be involved in both the response to pathogens and the maintenance of homeostasis.
Dengue Virus Type 2 Antagonizes IFN-α but Not IFN-γ Antiviral Effect via Down-Regulating Tyk2-STAT Signaling in the Human Dendritic Cell
Authors: Ho Ling-Jun , Hung Li-Feng , Weng Chun-Yi , Wu Wan-Lin , Chou Ping , Lin Yi-Ling , Chang Deh-Ming , Tai Tong-Yuan , Lai Jenn-Haung
Published: April 2014

The immunopathogenesis mechanism of dengue virus (DV) infection remains elusive. We previously showed that the target of DV in humans is dendritic cells (DCs), the primary sentinels of immune system. We also observed that despite the significant amount of IFN-α induced; DV particles remain massively produced from infected DCs. It suggests that DV may antagonize the antiviral effect of IFN-α. Recent work in animal studies demonstrated the differential critical roles of antiviral cytokines, namely IFN-α/IFN-β and IFN-γ, in blocking early viral production and in preventing viral-mediated disease, respectively. In this study, we examined the effects of IFN-α and IFN-γ in DV infection of monocyte-derived DCs. We showed that the preinfection treatment with either IFN-α or IFN-γ effectively armed DCs and limited viral production in infected cells. However, after infection, DV developed mechanisms to counteract the protection from lately added IFN-α, but not IFN-γ. Such a selective antagonism on antiviral effect of IFN-α, but not IFN-γ, correlated with down-regulated tyrosine-phosphorylation and DNA-binding activities of STAT1 and STAT3 transcription factors by DV. Furthermore, subsequent studies into the underlying mechanisms revealed that DV attenuated IFN-α-induced tyrosine-phosphorylation of Tyk2, an upstream molecule of STAT activation, but had no effect on expression of both IFN-α receptor 1 and IFN-α receptor 2. Moreover, DV infection by itself could activate STAT1 and STAT3 through IFN-α-dependent and both IFN-α-dependent and IFN-α-independent mechanisms, respectively. These observations provide very useful messages with physiological significance in investigation of the pathogenesis, the defense mechanisms of human hosts and the therapeutic considerations in DV infection.
The Critical Role of LIGHT in Promoting Intestinal Inflammation and Crohn’s Disease
Authors: Wang Jing , Anders Robert A. , Wang Yang , Turner Jerrold R. , Abraham Clara , Pfeffer Klaus , Fu Yang-Xin
Published: April 2014

Crohn’s disease (CD) is a type of inflammatory bowel disease associated with increased Th1 cytokines and unique pathological features. However, its pathogenesis has not been fully understood. Previous studies showed that homologous to lymphotoxin, exhibits inducible expression, competes with herpesvirus glycoprotein D for HVEM on T cells (LIGHT) transgenic (Tg) mice develop autoimmunity including intestinal inflammation with a variable time course. In this study, we establish an experimental model for CD by adoptive transfer of Tg mesenteric lymph node cells into RAG−/− mice. The recipients of Tg lymphocytes rapidly develop a disease strikingly similar to the key pathologic features and cytokine characterization observed in CD. We demonstrate that, as a costimulatory molecule, LIGHT preferentially drives Th1 responses. LIGHT-mediated intestinal disease is dependent on both of its identified signaling receptors, lymphotoxin β receptor and herpes virus entry mediator, because LIGHT Tg mesenteric lymph node cells do not cause intestinal inflammation when transferred into the lymphotoxin β receptor-deficient mice, and herpes virus entry mediator on donor T cells is required for the full development of disease. Furthermore, we demonstrated that up-regulation of LIGHT is associated with active CD. These data establish a new mouse model resembling CD and suggest that up-regulation of LIGHT may be an important mediator of CD pathogenesis.
Thymic Stromal Lymphopoietin Expression Is Increased in Asthmatic Airways and Correlates with Expression of Th2-Attracting Chemokines and Disease Severity
Authors: Ying Sun , O’Connor Brian , Ratoff Jonathan , Meng Qiu , Mallett Kirsty , Cousins David , Robinson Douglas , Zhang Guizhen , Zhao Jisheng , Lee Tak H. , Corrigan Chris
Published: April 2014

Thymic stromal lymphopoietin (TSLP) is said to increase expression of chemokines attracting Th2 T cells. We hypothesized that asthma is characterized by elevated bronchial mucosal expression of TSLP and Th2-attracting, but not Th1-attracting, chemokines as compared with controls, with selective accumulation of cells bearing receptors for these chemokines. We used in situ hybridization and immunohistochemistry to examine the expression and cellular provenance of TSLP, Th2-attracting (thymus and activation-regulated chemokine (TARC)/CCL17, macrophage-derived chemokine (MDC)/CCL22, I-309/CCL1) and Th1-attracting (IFN-γ-inducible protein 10 (IP-10)/CXCL10, IFN-inducible T cell α-chemoattractant (I-TAC)/CXCL11) chemokines and expression of their receptors CCR4, CCR8, and CXCR3 in bronchial biopsies from 20 asthmatics and 15 normal controls. The numbers of cells within the bronchial epithelium and submucosa expressing mRNA for TSLP, TARC/CCL17, MDC/CCL22, and IP-10/CXCL10, but not I-TAC/CXCL11 and I-309/CCL1, were significantly increased in asthmatics as compared with controls (p ≤ 0.018). TSLP and TARC/CCL17 expression correlated with airway obstruction. Although the total numbers of cells expressing CCR4, CCR8, and CXCR3 did not significantly differ in the asthmatics and controls, there was evidence of selective infiltration of CD4+/CCR4+ T cells in the asthmatic biopsies which correlated with TARC and MDC expression and airway obstruction. Epithelial cells, endothelial cells, neutrophils, macrophages, and mast cells were significant sources of TSLP and chemokines. Our data implicate TSLP, TARC/CCL17, MDC/CCL22, and IP-10/CXCL10 in asthma pathogenesis. These may act partly through selective development and retention, or recruitment of Th2 cells bearing their receptors.
Correlates of Delayed Disease Progression in HIV-1-Infected Kenyan Children
Authors: Chakraborty Rana , Morel Anne-Sophie , Sutton Julian K. , Appay Victor , Ripley Ruth M. , Dong Tao , Rostron Tim , Ogola Simon , Palakudy Tresa , Musoke Rachel , D’Agostino Angelo , Ritter Mary , Rowland-Jones Sarah L.
Published: April 2014

Without treatment most HIV-1-infected children in Africa die before their third birthday (>89%) and long-term nonprogressors are rare. The mechanisms underlying nonprogression in HIV-1-infected children are not well understood. In the present study, we examined potential correlates of delayed HIV disease progression in 51 HIV-1-infected African children. Children were assigned to progression subgroups based on clinical characterization. HIV-1-specific immune responses were studied using a combination of ELISPOT assays, tetramer staining, and FACS analysis to characterize the magnitude, specificity, and functional phenotype of HIV-1-specific CD8+ and CD4+ T cells. Host genetic factors were examined by genotyping with sequence-specific primers. HIV-1 nef gene sequences from infecting isolates from the children were examined for potential attenuating deletions. Thymic output was measured by T cell rearrangement excision circle assays. HIV-1-specific CD8+ T cell responses were detected in all progression groups. The most striking attribute of long-term survivor nonprogressors was the detection of HIV-1-specific CD4+ Th responses in this group at a magnitude substantially greater than previously observed in adult long-term nonprogressors. Although long-term survivor nonprogressors had a significantly higher percentage of CD45RA+CD4+ T cells, nonprogression was not associated with higher thymic output. No protective genotypes for known coreceptor polymorphisms or large sequence deletions in the nef gene associated with delayed disease progression were identified. In the absence of host genotypes and attenuating mutations in HIV-1 nef, long-term surviving children generated strong CD4+ T cell responses to HIV-1. As HIV-1-specific helper cells support anti-HIV-1 effector responses in active disease, their presence may be important in delaying disease progression.
Human BDCA-1-Positive Blood Dendritic Cells Differentiate into Phenotypically Distinct Immature and Mature Populations in the Absence of Exogenous Maturational Stimuli: Differentiation Failure in HIV Infection
Authors: Patterson Steven , Donaghy Heather , Amjadi Parisa , Gazzard Brian , Gotch Frances , Kelleher Peter
Published: April 2014

Current immunological opinion holds that myeloid dendritic cell (mDC) precursors migrate from the blood to the tissues, where they differentiate into immature dermal- and Langerhans-type dendritic cells (DC). Tissue DC require appropriate signals from pathogens or inflammatory cytokines to mature and migrate to secondary lymphoid tissue. We show that purified blood mDC cultured in vitro with GM-CSF and IL-4, but in the absence of added exogenous maturation stimuli, rapidly differentiate into two maturational and phenotypically distinct populations. The major population resembles immature dermal DC, being positive for CD11b, CD1a, and DC-specific ICAM-3-grabbing nonintegrin. They express moderate levels of MHC class II and low levels of costimulatory molecules. The second population is CD11b−/low and lacks CD1a and DC-specific ICAM-3-grabbing nonintegrin but expresses high levels of MHC class II and costimulatory molecules. Expression of CCR7 on the CD11b−/low population and absence on the CD11b+ cells further supports the view that these cells are mature and immature, respectively. Differentiation into mature and immature populations was not blocked by polymyxin B, an inhibitor of LPS. Neither population labeled for Langerin, E-cadherin, or CCR6 molecules expressed by Langerhans cells. Stimulation of 48-h cultured DC with LPS, CD40L, or poly(I:C) caused little increase in MHC or costimulatory molecule expression in the CD11b−/low DC but caused up-regulated expression in the CD11b+ cells. In HIV-infected individuals, there was a marked decrease in the viability of cultured blood mDC, a failure to differentiate into the two populations described for normal donors, and an impaired ability to stimulate T cell proliferation.
Ex Vivo Characterization of Multiepitopic Tumor-Specific CD8 T Cells in Patients with Chronic Myeloid Leukemia: Implications for Vaccine Development and Adoptive Cellular Immunotherapy
Authors: Gannagé Monique , Abel Michal , Michallet Anne-Sophie , Delluc Stéphanie , Lambert Marion , Giraudier Stéphane , Kratzer Roland , Niedermann Gabriele , Saveanu Loredana , Guilhot François , Camoin Luc , Varet Bruno , Buzyn Agnès , Caillat-Zucman Sophie
Published: April 2014

Identification of tumor-associated Ags is a prerequisite for vaccine-based and adoptive immune therapies. Some tumor-associated Ags elicit specific CD8 T cells in patients with chronic myeloid leukemia (CML). Here, we characterized ex vivo responses of CD8 T cells from CML patients to extrajunction bcr-abl peptides and telomerase 540–548 hTert, PR1, and WT1 peptides. CML-specific CD8 T cells were present in most treated patients and were usually multiepitopic: WT1, hTert, PR1, and bcr74 tetramer+ cells were detected in 85, 82, 67, and 61% of patients, respectively. The breadth and magnitude of these responses did not differ significantly according to treatment or disease status. CML-specific tetramer+ CD8 T cells had a predominantly memory phenotype, an intermediate perforin content, and low intracellular IFN-γ accumulation in the presence of the relevant peptide. However, in short-term culture with HLA-matched leukemia cells, the patients’ memory T cells were specifically reactivated to become IFN-γ-producing effector cells, suggesting that CD8 T cell precursors with lytic potential are present in vivo and can be activated by appropriate stimulation. In conclusion, this study shows that multiepitopic tumor-specific CD8 T cell responses occur naturally in most CML patients, opening the way to new strategies for enhancing anti-CML immunity, in particular in patients with minimal residual disease.