bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunoendocrine Interactions During Chronic Cysticercosis Determine Male Mouse Feminization: Role of IL-6
Authors: Morales-Montor Jorge , Baig S. , Mitchell R. , Deway K. , Hallal-Calleros C. , Damian R. T.
Published: April 2014

Taenia crassiceps cysticercosis results in an impressive feminization in male mice during chronic infection, characterized by increased serum estradiol levels 100 times their normal values, while those of testosterone and dihydrotestosterone are decreased by 85 and 95% respectively. Concomitantly, the levels of follicle-stimulating hormone and IL-6 are increased 70 and 90 times their normal values in the infected male mice. Since a specific Th1/Th2 shift of the immune response has been previously reported during the chronic infection, and this shift may be associated with the feminization process, we proposed that this shift is induced by immunoendocrine interactions during the disease, and this gives way to a change in the initial resistance to the infection in the male mice, which become as susceptible as female mice. To confirm this hypothesis, we depleted immune system activity in two different ways: total body irradiation and neonatal thymectomy. Our results show that when immune system activity is depleted using either strategy, the male mice do not feminize, and the levels of follicle-stimulating hormone and IL-6 are inhibited. Depletion of IL-6 using IL-6−/− knockout mice does not produce the feminization process stated above, while restitution of the IL-6−/− knockout, irradiated, and thymectomized mice with murine recombinant IL-6 restores the feminization process. Expression of the IL-6 gene was found only in the testes and spleen of infected animals. Our results illustrate the importance of immunoendocrine interactions during a parasitic disease and show a possible new mechanism of parasite establishment in an initially resistant host.
Leishmania amazonensis-Dendritic Cell Interactions In Vitro and the Priming of Parasite-Specific CD4+ T Cells In Vivo
Authors: Qi Hai , Popov Vsevolod , Soong Lynn
Published: April 2014

The progressive disease following Leishmania amazonensis infection in mice requires functional CD4+ T cells, which are primed to a disease-promoting phenotype during the infection. To understand how these pathogenic T cells are generated and the role of dendritic cells (DCs) in this process, we use DCs of susceptible BALB/c and resistant C3H/HeJ mice to examine parasite-DC interactions in vitro as well as the effector phenotype of T cells primed by parasite-exposed DCs in vivo. Our results demonstrate that amastigotes and metacyclics efficiently enter and activate DCs of both genetic backgrounds. Infection with amastigotes fails to induce CD40-depedent IL-12 production, but rather potentiates IL-4 production in BALB/c DCs. Upon transfer into syngeneic recipients, amastigote-exposed BALB/c DCs prime parasite-specific Th cells to produce significantly higher levels of IL-4 and IL-10 than their C3H/HeJ counterparts. Transfer studies with IL-4−/− DCs indicate that this enhanced Th2 priming seen in BALB/c mice is partially due to the IL-4 production by amastigote-carrying DCs. These results suggest that L. amazonensis amastigotes may condition DCs of a susceptible host to a state that favors activation of pathogenic CD4+ T cells, and thereby provide a new perspective on the pathogenesis of cutaneous leishmaniasis and protozoan parasite-host interactions in general.
Quantifying the Relationship Between Multiple Immunological Parameters and Host Resistance: Probing the Limits of Reductionism
Authors: Keil Deborah , Luebke Robert W. , Pruett Stephen B.
Published: April 2014

Although reductionist experimental designs are excellent for identifying cells, molecules, or functions involved in resistance to particular microbes or cancer cells, they do not provide an integrated, quantitative view of immune function. In the present study, mice were treated with either dexamethasone (DEX) or cyclosporin A (CyA), and immune function and host resistance were evaluated. Multivariate statistical methods were used to describe the relative importance of a broad range of immunological parameters for host resistance in mice treated with various dosages of DEX. Multiple regression and logistic regression analysis indicated that changes in 24 immunological parameters explained a substantial portion of the changes in resistance to B16F10 tumor cells or streptococcus group B. However, at least 40% of the change in host resistance remained unexplained. DEX at all dosages substantially suppressed numerous relevant immunological parameters, but significantly decreased resistance to Listeria monocytogenes only at the highest dosage. In contrast, CyA substantially decreased resistance to L. monocytogenes at dosages that caused relatively minor suppression of just a few immunological parameters (unfortunately, CyA data and host resistance data for L. monocytogenes were not suitable for multivariate analysis). These results illustrate that mathematical models can be used to explain changes in host resistance on the basis of changes in immune parameters, and that moderate changes in relevant immunological parameters may not produce the types of changes in host resistance expected on the basis of results from reductionist experimental designs.
Phosphatidylinositol 3-Kinase Confers Resistance to Encephalomyocarditis and Herpes Simplex Virus-Induced Cell Death Through the Activation of Distinct Downstream Effectors
Authors: Prejean Christine , Sarma Tulika , Kurnasov Oleg , Usacheva Anna , Hemmings Brian , Cantley Lewis , Fruman David A. , Morrison Lynda A. , Buller R. Mark , Colamonici Oscar R.
Published: April 2014

The Janus kinase/STAT pathway has emerged as the paradigm of IFN-induced protection from viral infections. However, the possible participation of other signaling proteins in this protection is not clearly understood. In this report, we demonstrate that activation of phosphatidylinositol 3-kinase (PI3K) by either serum factors or IFNs blocks cell death induced by encephalomyocarditis virus (EMCV) and HSV. This increased resistance to virus-induced cell death does not involve the activation of the STAT pathway and occurs in the presence of normal viral replication. Interestingly, the cell uses two different PI3K regulated pathways to block EMCV- and HSV-induced cell death. The increased sensitivity of p85α−/− embryonic fibroblasts to EMCV-induced cell death is specifically corrected by overexpression of an activated allele of Akt/protein kinase B, but not activated mitogen-activated protein kinase extracellular kinase. Conversely, the augmented sensitivity of p85α−/− cells to HSV-induced cell death was compensated for by expression of an activated form of mitogen-activated protein kinase extracellular kinase, but not by activated Akt/protein kinase B. We conclude from these data that PI3K-activated pathways function in parallel with the Janus kinase/STAT pathway to protect cells from the lethal effects of viruses.
A Dual-Function DNA Vaccine Encoding Carcinoembryonic Antigen and CD40 Ligand Trimer Induces T Cell-Mediated Protective Immunity Against Colon Cancer in Carcinoembryonic Antigen-Transgenic Mice
Authors: Xiang Rong , Primus F. James , Ruehlmann J. Michael , Niethammer Andreas G. , Silletti Steve , Lode Holger N. , Dolman Carrie S. , Gillies Stephen D. , Reisfeld Ralph A.
Published: April 2014

A carcinoembryonic Ag (CEA)-based DNA vaccine encoding both CEA and CD40 ligand trimer achieved effective tumor-protective immunity against murine colon carcinoma in CEA-transgenic mice by activating both naive T cells and dendritic cells. Peripheral T cell tolerance to CEA was broken in a prophylactic model by this novel, dual-function DNA vaccine, whose efficacy was further enhanced by boosts with a recombinant Ab-IL-2 fusion protein (huKS1/4-IL-2). These conclusions are supported by four lines of evidence. First, a lethal challenge of MC38-CEA-KS Ag murine colon carcinoma cells was for the first time completely rejected in 100% of experimental animals treated by oral gavage of this DNA vaccine carried by attenuated Salmonella typhimurium, followed by five boosts with huKS1/4-IL-2. Second, specific activation of dendritic cells was indicated by their marked up-regulation in expression of costimulatory molecules B7.1 (CD80), B7.2 (CD86), and ICAM-1. Third, a decisive increase over control values was observed in both MHC class I Ag-restricted cytotoxicity of CTLs from successfully vaccinated mice and secretion of proinflammatory cytokines IFN-γ and IL-12. Fourth, activation of CTLs was augmented, as indicated by up-regulation of activity markers LFA-1, CD25, CD28, and CD69. Taken together, these results suggest that a dual-function DNA vaccine encoding CEA and CD40 ligand trimer combined with tumor-targeted IL-2 may be a promising strategy for the rational development of DNA-based cancer vaccines for future clinical applications.
Distinct CD8 T Cell Functions Mediate Susceptibility to Histoplasmosis During Chronic Viral Infection
Authors: Wu-Hsieh Betty A. , Whitmire Jason K. , de Fries Rici , Lin Jr-Shiuan , Matloubian Mehrdad , Ahmed Rafi
Published: April 2014

It has long been recognized that some viral infections result in generalized immune suppression. In acute infections, this period of suppressed immunity is relatively short. However, chronic infections associated with a prolonged period of immune suppression present far greater risks. Here, we examined the role of CD8 T cell responses following viral infection in immunity to systemic histoplasmosis. Although wild-type mice with systemic histoplasmosis were able to control the infection, those simultaneously infected with lymphocytic choriomeningitis virus clone 13 showed reduced immunity with greater fungal burden and high mortality. The immune suppression was associated with loss of CD4 T cells and B cells, generalized splenic atrophy, and inability to mount a granulomatous response. Removing the anti-viral CD8 T cells in the coinfected mice enabled them to reduce the fungal burden and survive the infection. Their lymphoid organs were replenished with CD4 T and B cells. In contrast to wild-type mice, perforin-deficient mice infected with lymphocytic choriomeningitis virus clone 13 and Histoplasma showed an absence of immunopathology, but the animals still died. These results show that CD8 T cells can suppress immunity through different mechanisms; although immunopathology is perforin-dependent, lethality is perforin-independent.
Acute Toxoplasmosis Leads to Lethal Overproduction of Th1 Cytokines
Authors: Mordue Dana G. , Monroy Fernando , La Regina Marie , Dinarello Charles A. , Sibley L. David
Published: April 2014

Virulence in Toxoplasma gondii is strongly influenced by the genotype of the parasite. Type I strains uniformly cause rapid death in mice regardless of the host genotype or the challenge dose. In contrast, the outcome of infections with type II strains is highly dependent on the challenge dose and the genotype of the host. To understand the basis of acute virulence in toxoplasmosis, we compared low and high doses of the RH strain (type I) and the ME49/PTG strain (type II) of T. gondii in outbred mice. Differences in virulence were reflected in only modestly different growth rates in vivo, and both strains disseminated widely to different tissues. The key difference in the virulent RH strain was the ability to reach high tissue burdens rapidly following a low dose challenge. Lethal infections caused by type I (RH) or type II (PTG) strain infections were accompanied by extremely elevated levels of Th1 cytokines in the serum, including IFN-γ, TNF-α, IL-12, and IL-18. Extensive liver damage and lymphoid degeneration accompanied the elevated levels of cytokines produced during lethal infection. Increased time of survival following lethal infection with the RH strain was provided by neutralization of IL-18, but not TNF-α or IFN-γ. Nonlethal infections with a low dose of type II PTG strain parasites were characterized by a modest induction of Th1 cytokines that led to control of infection and minimal damage to host tissues. Our findings establish that overstimulation of immune responses that are normally necessary for protection is an important feature of acute toxoplasmosis.
Lack of CCR2 Results in Increased Mortality and Impaired Leukocyte Activation and Trafficking Following Infection of the Central Nervous System with a Neurotropic Coronavirus
Authors: Chen Benjamin P. , Kuziel William A. , Lane Thomas E.
Published: April 2014

In the present study, we evaluated the role of CCR2 in a model of viral-induced neurologic disease. An orchestrated expression of chemokines, including the CCR2 ligands monocyte chemoattractant protein-1/CCL2 and monocyte chemoattractant protein-3/CCL7, occurs within the CNS following infection with mouse hepatitis virus (MHV). Infection of mice lacking CCR2 (CCR2−/−) with MHV resulted in increased mortality and enhanced viral recovery from the brain that correlated with reduced (p ≤ 0.04) T cell and macrophage/microglial (determined by F4/80 Ag expression, p ≤ 0.004) infiltration into the CNS. Moreover, MHV-infected CCR2−/− mice displayed a significant decrease in Th1-associated factors IFN-γ (p ≤ 0.001) and RANTES/CCL5 (p ≤ 0.002) within the CNS as compared with CCR2+/+ mice. Further, peripheral CD4+ and CD8+ T cells from immunized CCR2−/− mice displayed a marked reduction in IFN-γ production in response to viral Ag and did not migrate into the CNS of MHV-infected recombination-activating gene (RAG)1−/− mice following adoptive transfer. In addition, macrophage/microglial infiltration into the CNS of RAG1−/− mice receiving CCR2−/− splenocytes was reduced (p ≤ 0.05), which correlated with a reduction in the severity of demyelination (p ≤ 0.001) as compared with RAG1−/− mice receiving splenocytes from CCR2+/+ mice. Collectively, these results indicate an important role for CCR2 in host defense and disease by regulating leukocyte activation and trafficking.
High-Dose Leptin Activates Human Leukocytes Via Receptor Expression on Monocytes
Authors: Zarkesh-Esfahani Hamid , Pockley Graham , Metcalfe Russell A. , Bidlingmaier Martin , Wu Zida , Ajami Abolghasem , Weetman Anthony P. , Strasburger Christian J. , Ross Richard J. M.
Published: April 2014

Leptin is capable of modulating the immune response. Proinflammatory cytokines induce leptin production, and we now demonstrate that leptin can directly activate the inflammatory response. RNA expression for the leptin receptor (Ob-R) was detectable in human PBMCs. Ob-R expression was examined at the protein level by whole blood flow cytometry using an anti-human Ob-R mAb 9F8. The percentage of cells expressing leptin receptor was 25 ± 5% for monocytes, 12 ± 4% for neutrophils, and 5 ± 1% for lymphocytes (only B lymphocytes). Incubation of resting PBMCs with leptin induced rapid expression of TNF-α and IL-6 mRNA and a dose-dependent production of TNF-α and IL-6 by monocytes. Incubation of resting PBMCs with high-dose leptin (250 ng/ml, 3–5 days) induced proliferation of resting cultured PBMCs and their secretion of TNF-α (5-fold), IL-6 (19-fold), and IFN-γ (2.5-fold), but had no effect on IL-4 secretion. The effect of leptin was distinct from, and additive to, that seen after exposure to endotoxin or activation by the mixed lymphocyte reaction. In conclusion, Ob-R is expressed on human circulating leukocytes, predominantly on monocytes. At high doses, leptin induces proinflammatory cytokine production by resting human PBMCs and augments the release of these cytokines from activated PBMCs in a pattern compatible with the induction of Th1 cytokines. These results demonstrate that leptin has a direct effect on the generation of an inflammatory response. This is of relevance when considering leptin therapy and may partly explain the relationship among leptin, proinflammatory cytokines, insulin resistance, and obesity.
Induction of Hypoxia-Inducible Factor-1α and Activation of Caspase-3 in Hypoxia-Reoxygenated Bone Marrow Stroma Is Negatively Regulated by the Delayed Production of Substance P
Authors: Qian Jing , Ramroop Kavita , McLeod Alnela , Bandari Persis , Livingston David H. , Harrison Jonathan S. , Rameshwar Pranela
Published: April 2014

The bone marrow (BM), which is the major site of immune cell development in the adult, responds to different stimuli such as inflammation and hemorrhagic shock. Substance P (SP) is the major peptide encoded by the immune/hemopoietic modulator gene, preprotachykinin-1 (PPT-I). Differential gene expression using a microarray showed that SP reduced hypoxia-inducible factor-1α (HIF-1α) mRNA levels in BM stroma. Because long-term hypoxia induced the expression of PPT-I in BM mononuclear cells, we used timeline studies to determine whether PPT-I is central to the biologic responses of BM stroma subjected to 30-min hypoxia (pO2 = 35 mm Hg) followed by reoxygenation. HIF-1α mRNA and protein levels were increased up to 12 h. At this time, β-PPT-I mRNA was detected with the release of SP at 16 h. SP release correlated with down-regulation of HIF-1α to baseline. A direct role for SP in HIF-1α expression was demonstrated as follows: 1) transient knockout of β-PPT-I showed an increase in HIF-1α expression up to 48 h of reoxygenation; and 2) HIF-1α expression remained baseline during reoxygenation when stroma was subjected to hypoxia in the presence of SP. Reoxygenation activated the PPT-I promoter with concomitant nuclear translocation of HIF-1α that can bind to the respective consensus sequences within the PPT-I promoter. SP reversed active caspase-3, an indicator of apoptosis and erythropoiesis, to homeostasis level after reoxygenation of hypoxic stroma. The results show that during reoxgenation the PPT-I gene acts as a negative regulator on the expression of HIF-1α and active caspase-3 in BM stroma subjected to reoxygenation.
The Functional Role of Rho and Rho-Associated Coiled-Coil Forming Protein Kinase in Eotaxin Signaling of Eosinophils
Authors: Adachi Tetsuya , Vita Randi , Sannohe Satoshi , Stafford Susan , Alam Rafeul , Kayaba Hiroyuki , Chihara Junichi
Published: April 2014

The CC chemokine eotaxin plays a pivotal role in local accumulation of eosinophils. Very little is known about the eotaxin signaling in eosinophils except the activation of the mitogen-activated protein (MAP) kinase family. The p21 G protein Rho and its substrate Rho-associated coiled-coil forming protein kinase (ROCK) regulate the formation of stress fibers and focal adhesions. In the present study, we studied the functional relevance of Rho and ROCK in eosinophils using the ROCK inhibitor (Y-27632) and exoenzyme C3, a specific Rho inhibitor. Eotaxin stimulates activation of Rho A and ROCK II in eosinophils. Exoenzyme C3 almost completely inhibited the ROCK activity, indicating that ROCK is downstream of Rho. We then examined the role of Rho and ROCK in eosinophil chemotaxis. The eotaxin-induced eosinophil chemotaxis was significantly inhibited by exoenzyme C3 or Y-27632. Because extracellular signal-regulated kinase (ERK)1/2 and p38 MAP kinases are activated by eotaxin and are critical for eosinophil chemotaxis, we investigated whether Rho and ROCK are upstream of these MAP kinases. C3 partially inhibited eotaxin-induced phosphorylation of ERK1/2 but not p38. In contrast, neither ERK1/2 nor p38 phosphorylation was abrogated by Y-27632. Both C3 and Y-27632 reduced reactive oxygen species production from eosinophils. We conclude that both Rho and ROCK are important for eosinophil chemotaxis and reactive oxygen species production. There is a dichotomy of downstream signaling pathways of Rho, namely, Rho-ROCK and Rho-ERK pathways. Taken together, eosinophil chemotaxis is regulated by multiple signaling pathways that involve at least ROCK, ERK, and p38 MAP kinase.
Intracisternally Localized Bacterial DNA Containing CpG Motifs Induces Meningitis
Authors: Deng Guo-Min , Liu Zai-Qing , Tarkowski Andrej
Published: April 2014

Unmethylated CpG motifs are frequently found in bacterial DNA, and have recently been shown to exert immunostimulatory effects on leukocytes. Since bacterial infections in the CNS will lead to local release of prokaryotic DNA, we wanted to investigate whether such an event might trigger meningitis. To that end, we have intracisternally injected mice and rats with bacterial DNA and oligonucleotides containing CpG motifs. Histopathological signs of meningitis were evident within 12 h and lasted for at least 14 days, and were characterized by an influx of monocytic, Mac-3+ cells and by a lack of T lymphocytes. To study the mechanisms whereby unmethylated CpG DNA gives rise to meningitis, we deleted the monocyte/macrophage population leading to abrogation of brain inflammation. Also, interaction with NF-κB using antisense technology led to down-regulation of proinflammatory cytokine production and frequency of meningitis. Furthermore, specific interactions with vascular selectin expression and inhibition of NO synthase led to a significant amelioration of meningitis, altogether indicating that this condition is dependent on macrophages and their products. In contrast, neutrophils, NK cells, T/B lymphocytes, IL-12, and complement system were not instrumental in meningitis triggered by bacterial DNA containing CpG motifs. This study proves that bacterial DNA containing unmethylated CpG motifs induces meningitis, and indicates that this condition is mediated in vivo by activated macrophages.
Cockroach Allergen-Induced Eosinophilic Airway Inflammation in HLA-DQ/Human CD4+ Transgenic Mice
Authors: Papouchado Bettina G. , Chapoval Svetlana P. , Marietta Eric V. , Weiler Catherine R. , David Chella S.
Published: April 2014

Airway eosinophilic inflammation is a characteristic feature of allergic asthma. Exposure to allergens produced by the German cockroach (Blattella germanica) is a risk factor for allergic disease in genetically predisposed individuals, and has been linked to an increase in asthma morbidity among cockroach-sensitive inner city children. To determine the role and contribution of specific HLA class II in the pathogenesis of allergic airway inflammation in cockroach-induced asthma, we generated double-transgenic, double-knockout mice expressing human HLA-DQ8, HLA-DQ6, and CD4 molecules in the absence of mouse class II and mouse CD4. Mice were actively immunized and later challenged intranasally with cockroach allergen extract. These mice developed bronchoalveolar lavage fluid (BALF) eosinophilia and pulmonary eosinophilia. This was accompanied by an increase in total protein levels, IL-5, and IL-13 in BALF. There were also elevated levels of cockroach-specific serum IgG1 and total serum IgE. Histological analysis revealed peribronchial and perivascular eosinophilic inflammation in cockroach-treated mice. Other pathologic changes in the airways were epithelial cell hypertrophy and mucus production. Treatment with anti-DQ mAb significantly reduced pulmonary and BALF eosinophilia in cockroach allergen-sensitized mice. Aβ0 mice and transgenic mice expressing human CD4 molecule alone (without class II) or human HLA-DQ8 molecule (without CD4) treated in the same fashion showed no eosinophilia in bronchoalveolar fluid and no pulmonary parenchymal inflammation. Our results provide direct evidence that HLA-DQ molecules and CD4 T cells mediate cockroach-induced eosinophilic inflammation in the airways.
Constitutive Expression of Macrophage-Inflammatory Protein 2 (MIP-2) mRNA in Bone Marrow Gives Rise to Peripheral Neutrophils with Preformed MIP-2 Protein
Authors: Matzer Sigrid P. , Baumann Tobias , Lukacs Nicholas W. , Röllinghoff Martin , Beuscher H. Ulrich
Published: April 2014

Macrophage-inflammatory protein 2 (MIP-2) is a major CXC chemokine involved in the migration of polymorphonuclear neutrophils (PMNs) to sites of inflammation. Although cell culture experiments have identified different cell types that can produce MIP-2, the cellular sources in vivo are not clearly defined. By using immunohistochemical staining and analysis of chemokine mRNA expression, the present study aimed to localize cells producing MIP-2 in tissues of normal mice and mice challenged with Yersinia enterocolitica. The results showed a constitutive expression of MIP-2 mRNA in bone marrow (BM) of normal mice, but not in other organs such as spleen, lung, or liver. MIP-2 protein was found in all organs tested but it was exclusively associated with PMNs that stained positive with the cell surface marker Gr-1. Bacterial infection caused a 5-fold increase in the number of MIP-2-positive PMNs recruited to spleens concomitant with a strong increase of splenic MIP-2 mRNA. This correlated well with a 3-fold loss of MIP-2-producing cells in BM. Because MIP-2 mRNA expression in PMNs was increased after stimulation with TNF, the results indicate that newly recruited PMNs can supplement their MIP-2 content through TNF-stimulated transcription. Together, the data imply a constitutive production of MIP-2 by a subset of PMNs in BM and argue for the possibility of a rapid mobilization of MIP-2 through its storage in circulating PMNs.
Meningeal and Perivascular Macrophages of the Central Nervous System Play a Protective Role During Bacterial Meningitis
Authors: Polfliet Machteld M. J. , Zwijnenburg Petra J. G. , van Furth A. Marceline , van der Poll Tom , Döpp Ed A. , Renardel de Lavalette Chantal , van Kesteren-Hendrikx Esther M. L. , van Rooijen Nico , Dijkstra Christien D. , van den Berg Timo K.
Published: April 2014

Meningeal (MM) and perivascular macrophages (PVM) constitute major populations of resident macrophages in the CNS that can be distinguished from microglial cells. So far, there is no direct evidence that demonstrates a possible role of MM and PVM in the CNS during normal or pathologic conditions. To elucidate the role of the MM and PVM during CNS inflammation, we have developed a strategy using a single intraventricular injection of mannosylated clodronate liposomes, which results in a complete and selective depletion of the PVM and MM from the CNS. Depletion of the MM and PVM during experimental pneumococcal meningitis resulted in increased illness, which correlated with higher bacteria counts in the cerebrospinal fluid and blood. This was associated with a decreased influx of leukocytes into the cerebrospinal fluid, which occurred despite an elevated production of relevant chemokines (e.g., macrophage-inflammatory protein-2) and a higher expression of vascular adhesion molecules (e.g., VCAM-1). In contrast, the higher bacterial counts correlated with elevated production of local and systemic inflammatory mediators (e.g., IL-6) indicating enhanced local leukocyte and systemic immune activation, and this may explain the worsening of the clinical signs. These findings show that the PVM and MM play a protective role during bacterial meningitis and suggest that a primary action of these macrophages is to facilitate the influx of leukocytes at the blood-brain barrier. More in general, we demonstrate for the first time that the PVM and MM play a crucial role during inflammation in the CNS.
Contribution of Anaphylatoxin C5a to Late Airway Responses After Repeated Exposure of Antigen to Allergic Rats
Authors: Abe Masayoshi , Shibata Kazuhiko , Akatsu Hiroyasu , Shimizu Naomi , Sakata Noriyuki , Katsuragi Takeshi , Okada Hidechika
Published: April 2014

We attempted to elucidate the contribution of complement to allergic asthma. Rat sensitized to OVA received repeated intratracheal exposures to OVA for up to 3 consecutive days, and pulmonary resistance was then estimated for up to 6 h after the last exposure. Whereas the immediate airway response (IAR) in terms of RL tended to decrease in proportion to the number of OVA exposures, late airway response (LAR) became prominent only after three. Although premedication with two kinds of complement inhibitors, soluble complement receptor type 1 (sCR1) or nafamostat mesylate, resulted in inhibition of the IAR after either a single or a double exposure, the LAR was inhibited after the triple. Premedication with a C5a receptor antagonist (C5aRA) before every exposure to OVA also inhibited the LAR after three. Repeated OVA exposure resulted in eosinophil and neutrophil infiltration into the bronchial submucosa which was suppressed by premedication with sCR1 or C5aRA. Up-regulation of C5aR mRNA was shown in lungs after triple OVA exposure, but almost no up-regulation of C3aR. Pretreatment with sCR1 or C5aRA suppressed the up-regulation of C5aR expression as well as cytokine messages in the lungs. The suppression of LAR by pretreatment with sCR1 was reversed by intratracheal instillation of rat C5a desArg the action of which was inhibited by C5aRA. In contrast, rat C3a desArg or cytokine-induced neutrophil chemoattractant-1 induced cellular infiltration into the bronchial submucosa by costimulation with OVA, but these had no influence on the LAR. These differences might be explained by the fact that costimulation with OVA and C5a synergistically potentiated IAR, whereas that with OVA and either C3a or cytokine-induced neutrophil chemoattractant-1 did not. C5a generated by Ag-Ab complexes helps in the production of cytokines and contributes to the LAR after repeated exposure to Ag.
Production of Colony-Stimulating Factors and IL-5 by Organs from Three Types of Mice with Inflammatory Disease Due to Loss of the Suppressor of Cytokine Signaling-1
Authors: Metcalf Donald , Alexander Warren S. , Ryan Philip J. , Mifsud Sandra , Di Rago Ladina
Published: April 2014

Organs from neonatal mice dying from IFN-γ-dependent inflammatory disease initiated by loss of the gene encoding the suppressor of cytokine signaling-1 (SOCS-1) had a normal capacity to produce G-CSF in vitro but a reduced capacity to produce GM-CSF, most evident with the lung, and some reduction in the production of M-CSF by muscle tissue. In contrast, organs from mice lacking the genes for both SOCS-1 and IFN-γ had a normal capacity to produce CSFs. Organs from young adult mice dying with polymyositis and myocarditis that lacked SOCS-1 but were heterozygous for IFN-γ had a normal capacity to produce GM-CSF and M-CSF, but muscle tissue produced significantly increased amounts of G-CSF and IL-5 with IL-5 production also being elevated for the salivary gland, thymus, and heart. Loss of the IFN-γ gene alone had no impact on organ production of these cytokines in vitro. In none of the inflammatory disease models was IL-3 production detected. The SOCS-1 protein appears to have no direct influence on the cellular production of these cytokines and the abnormalities observed either depend on the coaction of IFN-γ, or more likely, are linked with the invasion and destruction of tissue by T lymphocytes, macrophages, eosinophils, and neutrophils. The ability of local organs to produce these proinflammatory cytokines could contribute to the development and progression of these inflammatory lesions.
Critical Role for IL-13 in the Development of Allergen-Induced Airway Hyperreactivity
Authors: Walter David M. , McIntire Jennifer J. , Berry Gerald , McKenzie Andrew N. J. , Donaldson Debra D. , DeKruyff Rosemarie H. , Umetsu Dale T.
Published: April 2014

Airway hyperresponsiveness to a variety of specific and nonspecific stimuli is a cardinal feature of asthma, which affects nearly 10% of the population in industrialized countries. Eosinophilic pulmonary inflammation, eosinophil-derived products, as well as Th2 cytokines IL-13, IL-4, and IL-5, have been associated with the development of airway hyperreactivity (AHR), but the specific immunological basis underlying the development of AHR remains controversial. Herein we show that mice with targeted deletion of IL-13 failed to develop allergen-induced AHR, despite the presence of vigorous Th2-biased, eosinophilic pulmonary inflammation. However, AHR was restored in IL-13−/− mice by the administration of recombinant IL-13. Moreover, adoptive transfer of OVA-specific Th2 cells generated from TCR-transgenic IL-13−/− mice failed to induce AHR in recipient SCID mice, although such IL-13−/− Th2 cells produced high levels of IL-4 and IL-5 and induced significant airway inflammation. These studies definitively demonstrate that IL-13 is necessary and sufficient for the induction of AHR and that eosinophilic airway inflammation in the absence of IL-13 is inadequate for the induction of AHR. Therefore, treatment of human asthma with antagonists of IL-13 may be very effective.
Adenosine-Dependent Airway Inflammation and Hyperresponsiveness in Partially Adenosine Deaminase-Deficient Mice
Authors: Chunn Janci L. , Young Hays W. J. , Banerjee Suman K. , Colasurdo Giuseppe N. , Blackburn Michael R.
Published: April 2014

Adenosine is a signaling nucleoside that is elevated in the lungs of asthmatics. We have engineered a mouse model that has elevated levels of adenosine as a result of the partial expression of the enzyme that metabolizes adenosine, adenosine deaminase (ADA). Mice with lowered levels of ADA enzymatic activity were generated by the ectopic expression of an ADA minigene in the gastrointestinal tract of otherwise ADA-deficient mice. These mice developed progressive lung inflammation and damage and died at 4–5 mo of age from respiratory distress. Associated with this phenotype was a progressive increase in lung adenosine levels. Examination of airway physiology at 6 wk of age revealed alterations in airway hyperresponsiveness. This was reversed following the lowering of adenosine levels using ADA enzyme therapy and also through the use of the adenosine receptor antagonist theophylline, implicating both the nucleoside and its receptors in airway physiological alterations. All four adenosine receptors were expressed in the lungs of both control and partially ADA-deficient mice. However, transcript levels for the A1, A2B, and A3 adenosine receptors were significantly elevated in partially ADA-deficient lungs. There was a significant increase in alveolar macrophages, and monocyte chemoattractant protein-3 was found to be elevated in the bronchial epithelium of these mice, which may have important implications in the regulation of pulmonary inflammation and airway hyperresponsiveness. Collectively, these findings suggest that elevations in adenosine can directly impact lung inflammation and physiology.
AMD3100, a Potent and Specific Antagonist of the Stromal Cell-Derived Factor-1 Chemokine Receptor CXCR4, Inhibits Autoimmune Joint Inflammation in IFN-γ Receptor-Deficient Mice
Authors: Matthys Patrick , Hatse Sigrid , Vermeire Kurt , Wuyts Anja , Bridger Gary , Henson Geoffrey W. , De Clercq Erik , Billiau Alfons , Schols Dominique
Published: April 2014

Autoimmune collagen-induced arthritis (CIA) in IFN-γR-deficient DBA/1 mice was shown to be reduced in severity by treatment with the bicyclam derivative AMD3100, a specific antagonist of the interaction between the chemokine stromal cell-derived factor-1 (SDF-1) and its receptor CXCR4. The beneficial effect of the CXCR4 antagonist was demonstrable when treatment was initiated between the time of immunization and appearance of the first symptoms. Treatment also reduced the delayed-type hypersensitivity response to the autoantigen, collagen type II. These observations are indicative of an action on a late event in the pathogenesis, such as chemokine-mediated attraction of leukocytes toward joint tissues. The notion of SDF-1 involvement was further supported by the observation that exogenous SDF-1 injected in periarthritic tissue elicited an inflammatory response that could be inhibited by AMD3100. The majority of leukocytes harvested from inflamed joints of mice with CIA were found to be Mac-1+ and CXCR4+, and AMD3100 was demonstrated to interfere specifically with chemotaxis and Ca2+ mobilization induced in vitro by SDF-1 on Mac-1+/CXCR4+ splenocytes. We conclude that SDF-1 plays a central role in the pathogenesis of murine CIA, by attracting Mac-1+/CXCR4+ cells to the inflamed joints.
Mature Dendritic Cells Infiltrate the T Cell-Rich Region of Oral Mucosa in Chronic Periodontitis: In Situ, In Vivo, and In Vitro Studies
Authors: Jotwani Ravi , Palucka Anna Karolina , Al-Quotub Montasr , Nouri-Shirazi Mahyar , Kim Jay , Bell Diana , Banchereau Jacques , Cutler Christopher W.
Published: April 2014

Previous studies have analyzed the lymphoid and myeloid foci within the gingival mucosa in health and chronic periodontitis (CP); however, the principal APCs responsible for the formation and organizational structure of these foci in CP have not been defined. We show that in human CP tissues, CD1a+ immature Langerhans cells predominantly infiltrate the gingival epithelium, whereas CD83+ mature dendritic cells (DCs) specifically infiltrate the CD4+ lymphoid-rich lamina propria. In vivo evidence shows that exacerbation of CP results in increased levels of proinflammatory cytokines that mediate DC activation/maturation, but also of counterregulatory cytokines that may prevent a Th-polarized response. Consistently, in vitro-generated monocyte-derived DCs pulsed with Porphyromonas gingivalis strain 381 or its LPS undergo maturation, up-regulate accessory molecules, and release proinflammatory (IL-1β, PGE2) and Th (IL-10, IL-12) cytokines. Interestingly, the IL-10:IL-12 ratio elicited from P. gingivalis-pulsed DCs was 3-fold higher than that from Escherichia coli-pulsed DCs. This may account for the significantly (p < 0.05) lower proliferation of autologous CD4+ T cells and reduced release of IFN-γ elicited by P. gingivalis-pulsed DCs. Taken together, these findings suggest a previously unreported mechanism for the pathophysiology of CP, involving the activation and in situ maturation of DCs by the oral pathogen P. gingivalis, leading to release of counterregulatory cytokines and the formation of T cell-DC foci.
Overexpression of the Wiskott-Aldrich Syndrome Protein N-Terminal Domain in Transgenic Mice Inhibits T Cell Proliferative Responses Via TCR Signaling Without Affecting Cytoskeletal Rearrangements
Authors: Sato Mitsuru , Tsuji Noriko M. , Gotoh Hideo , Yamashita Keizo , Hashimoto Koichi , Tadotsu Noriko , Yamanaka Harumichi , Sekikawa Kenji , Hashimoto Yasuhiro
Published: April 2014

Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterized by thrombocytopenia with small platelets, severe eczema, and recurrent infections due to defects in the immune system. The disease arises from mutations in the gene encoding the WAS protein (WASP), which plays a role as an adaptor molecule in signal transduction accompanied by cytoskeletal rearrangement in T cells. To investigate the functional domain of WASP, we developed transgenic mice overexpressing the WASP N-terminal region (exon 1–5) including the Ena/VASP homology 1 (pleckstrin homology/WASP homology 1) domain, in which the majority of mutations in WAS patients have been observed. WASP transgenic mice develop and grow normally under the specific pathogen-free environment, and showed normal lymphocyte development. However, proliferative responses and cytokine production induced by TCR stimulation were strongly inhibited in transgenic mice, whereas Ag receptor capping and actin polymerization were normal. These findings suggest that overexpressed Ena/VASP homology 1 (pleckstrin homology/WASP homology 1) domain of WASP inhibits the signaling from TCR without coupling of cytoskeletal rearrangement. WASP transgenic mice shown here could be valuable tools for further understanding the WASP-mediated processes.
T Cell Activation in Rheumatoid Synovium Is B Cell Dependent
Authors: Takemura Seisuke , Klimiuk Piotr A. , Braun Andrea , Goronzy Jörg J. , Weyand Cornelia M.
Published: April 2014

Rheumatoid arthritis results from a T cell-driven inflammation in the synovial membrane that is frequently associated with the formation of tertiary lymphoid structures. The significance of this extranodal lymphoid neogenesis is unknown. Microdissection was used to isolate CD4 T cells residing in synovial tissue T cell/B cell follicles. CD4 T cells with identical TCR sequences were represented in independent, nonadjacent follicles, suggesting recognition of the same Ag in different germinal centers. When adoptively transferred into rheumatoid arthritis synovium-SCID mouse chimeras, these CD4 T cell clones enhanced the production of IFN-γ, IL-1β, and TNF-α. In vivo activity of adoptively transferred CD4 T cells required matching of HLA-DRB1 alleles and also the presence of T cell/B cell follicles. HLA-DRB1-matched synovial tissues that were infiltrated by T cells, macrophages, and dendritic cells, but that lacked B cells, did not support the activation of adoptively transferred CD4 T cell clones, raising the possibility that B cells provided a critical function in T cell activation or harbored the relevant Ag. Dependence of T cell activation on B cells was confirmed in B cell depletion studies. Treatment of chimeric mice with anti-CD20 mAb inhibited the production of IFN-γ and IL-1β, indicating that APCs other than B cells could not substitute in maintaining T cell activation. The central role of B cells in synovial inflammation identifies them as excellent targets for immunosuppressive therapy.
Apoptosis-Inducing Human-Origin Fcε-Bak Chimeric Proteins for Targeted Elimination of Mast Cells and Basophils: A New Approach for Allergy Treatment
Authors: Belostotsky Ruth , Lorberboum-Galski Haya
Published: April 2014

During the past few years, many chimeric proteins have been developed to specifically target and kill cells expressing specific surface molecules. Generally these molecules carry a bacterial or plant toxin to destroy the unwanted cells. The major obstacle regarding these molecules in their clinical application is the immunogenicity and nonspecific toxicity associated with bacterial or plant toxins. We lately reported a new approach for construction of chimeric proteins: we successfully replaced bacterial or plant toxins with human apoptosis-inducing proteins. The resulting chimeras were shown to specifically induce apoptosis in the target cells. Taking advantage of the human apoptosis inducing proteins Bak and Bax as novel killing components, we have now constructed new chimeric proteins targeted against the human FcεRI, expressed mainly on mast cells and basophils. These cells are the main effectors of the allergic response. Treatment of the target cells with the new chimeric proteins, termed Fcε-Bak/Bax, had a dramatic effect on cell survival, causing apoptosis. The effect was specific to cells expressing the FcεRI of both human and, very unexpectedly, also of mouse origin. Moreover, interaction of the chimeric proteins with the mast cells did not cause degranulation. Fcε-Bak/Bax are new chimeric proteins of human origin and, as such, are expected to be both less immunogenic and less toxic and, thus, may be specific and efficient reagents for the treatment of allergic diseases.
Unique T Cell Effector Functions Elicited by Plasmodium falciparum Epitopes in Malaria-Exposed Africans Tested by Three T Cell Assays
Authors: Flanagan Katie L. , Lee Edwin A. M. , Gravenor Michael B. , Reece William H. H. , Urban Britta C. , Doherty Thomas , Bojang Kalifa A. , Pinder Margaret , Hill Adrian V. S. , Plebanski Magdalena
Published: April 2014

Natural immunity to malaria is characterized by low level CD4 T cell reactivity detected by either lymphoproliferation or IFN-γ secretion. Here we show a doubling in the detection rate of responders to the carboxyl terminus of circumsporozoite protein (CS) of Plasmodium falciparum by employing three T cell assays simultaneously: rapid IFN-γ secretion (ex vivo ELISPOT), IFN-γ secretion after reactivation of memory T cells and expansion in vitro (cultured ELISPOT), and lymphoproliferation. Remarkably, for no individual peptide did a positive response for one T cell effector function correlate with any other. Thus these CS epitopes elicited unique T cell response patterns in malaria-exposed donors. Novel or important epitope responses may therefore be missed if only one T cell assay is employed. A borderline correlation was found between anti-CS Ab levels and proliferative responses, but no correlation was found with ex vivo or cultured IFN-γ responses. This suggested that the proliferating population, but not the IFN-γ-secreting cells, contained cells that provide help for Ab production. The data suggest that natural immunity to malaria is a complex function of T cell subgroups with different effector functions and has important implications for future studies of natural T cell immunity.
Identification of HLA-B27-Restricted Peptides from the Chlamydia trachomatis Proteome with Possible Relevance to HLA-B27-Associated Diseases
Authors: Kuon Wolfgang , Holzhütter Hermann-Georg , Appel Heiner , Grolms Martina , Kollnberger Simon , Traeder Alexander , Henklein Peter , Weiss Elisabeth , Thiel Andreas , Lauster Roland , Bowness Paul , Radbruch Andreas , Kloetzel Peter-Michael , Sieper Joachim
Published: April 2014

The association of HLA-B27 with ankylosing spondylitis and reactive arthritis is the strongest one known between an MHC class I Ag and a disease. We have searched the proteome of the bacterium Chlamydia trachomatis for HLA-B27 binding peptides that are stimulatory for CD8+ cells both in a model of HLA-B27 transgenic mice and in patients. This was done by combining two biomathematical computer programs, the first of which predicts HLA-B27 peptide binding epitopes, and the second the probability of HLA-B27 peptide generation by the proteasome system. After preselection, immunodominant peptides were identified by Ag-specific flow cytometry. Using this approach we have identified for the first time nine peptides derived from different C. trachomatis proteins that are stimulatory for CD8+ T cells. Eight of these nine murine-derived peptides were recognized by cytotoxic T cells. The same strategy was used to identify B27-restricted chlamydial peptides in three patients with reactive arthritis. Eleven peptides were found to be stimulatory for patient-derived CD8+ T cells, of which eight overlapped those found in mice. Additionally, we applied the tetramer technology, showing that a B27/chlamydial peptide containing one of the chlamydial peptides stained CD8+ T cells in patients with Chlamydia-induced arthritis. This comprehensive approach offers the possibility of clarifying the pathogenesis of B27-associated diseases.
A Possible Role for CXCR4 and Its Ligand, the CXC Chemokine Stromal Cell-Derived Factor-1, in the Development of Bone Marrow Metastases in Neuroblastoma
Authors: Geminder Hila , Sagi-Assif Orit , Goldberg Lilach , Meshel Tsipi , Rechavi Gideon , Witz Isaac P. , Ben-Baruch Adit
Published: April 2014

The homing of hemopoietic stem cells to the bone marrow is mediated by specific interactions occurring between CXCR4, which is expressed on hemopoietic stem cells, and its ligand, stromal cell-derived factor-1 (SDF-1), a CXC chemokine secreted by bone marrow stromal cells. In the present study we evaluated the possibility that neuroblastoma cells use a mechanism similar to that used by hemopoietic stem cells to home to the bone marrow and adhere to bone marrow stromal cells. Our study suggests that CXCR4 expression may be a general characteristic of neuroblastoma cells. SH-SY5Y neuroblastoma cells express not only CXCR4, but also its ligand, SDF-1. CXCR4 expression on SH-SY5Y neuroblastoma cells is tightly regulated by tumor cell-derived SDF-1, as demonstrated by the ability of neutralizing Abs against human SDF-1α to up-regulate CXCR4 expression on the tumor cells. The reduction in CXCR4 expression following short term exposure to recombinant human SDF-1α can be recovered as a result of de novo receptor synthesis. Recombinant human SDF-1α induces the migration of CXCR4-expressing SH-SY5Y neuroblastoma cells in CXCR4- and heterotrimeric G protein-dependent manners. Furthermore, SH-SY5Y cells interact at multiple levels with bone marrow components, as evidenced by the fact that bone marrow-derived constituents promote SH-SY5Y cell migration, adhesion to bone marrow stromal cells, and proliferation. These results suggest that SH-SY5Y neuroblastoma cells are equipped with adequate machinery to support their homing to the bone marrow. Therefore, the ability of neuroblastoma tumors to preferentially form metastases in the bone marrow may be influenced by a set of complex CXCR4-SDF-1 interactions.