bluuebunny/crossref_metadata_2025 huggingface dataset:
Social Stress Enhances Allergen-Induced Airway Inflammation in Mice and Inhibits Corticosteroid Responsiveness of Cytokine Production
Authors: Bailey Michael T. , Kierstein Sonja , Sharma Satish , Spaits Matthew , Kinsey Steven G. , Tliba Omar , Sheridan John F. , Panettieri Reynold A. , Haczku Angela
Published: June 2009

Chronic psychosocial stress exacerbates asthma, but the underlying mechanisms remain poorly understood. We hypothesized that psychosocial stress aggravates allergic airway inflammation by altering innate immune cell function. The effects of stress on airway inflammation, lung function, and glucocorticoid responsiveness were studied in a novel in vivo murine model of combined social disruption stress and allergic sensitization. The effects of corticosterone were assessed on cytokine profile and glucocorticoid receptor activation in LPS-stimulated spleen cell cultures in vitro. Airway inflammation resolved 48 h after a single allergen provocation in sensitized control mice, but not in animals that were repeatedly exposed to stress before allergen challenge. The enhanced eosinophilic airway inflammation 48 h after allergen challenge in these mice was associated with increased levels of IL-5, GM-CSF, IgG1, thymus-activated and regulatory chemokine, TNF-α, and IL-6 in the airways and a diminished inhibition of these mediators by corticosterone in LPS-stimulated splenocyte cultures in vitro. Stress-induced reduction of the corticosteroid effects paralleled increased p65 expression and a decreased DNA-binding capability of the glucocorticoid receptor in vitro. Furthermore, glucocorticoid receptor mRNA and protein expression in the lungs of mice exposed to both stress and allergen was markedly reduced in comparison with that in either condition alone or in naive mice. Thus, exposure to repeated social stress before allergen inhalation enhances and prolongs airway inflammation and alters corticosterone responsiveness. We speculate that these effects were mediated at least in part by impaired glucocorticoid receptor expression and function.
Regulation of DNA Demethylation during Maturation of CD4+ Naive T Cells by the Conserved Noncoding Sequence 1
Authors: Aoki Kazuhisa , Sato Noriko , Yamaguchi Atsumi , Kaminuma Osamu , Hosozawa Takumi , Miyatake Shoichiro
Published: June 2009

Demethylation of transcriptional regulatory elements and gene coding regions is an important step in the epigenetic regulation of gene expression. Several noncoding conserved regions are required for the efficient transcription of cytokine genes. In this paper, we show that the deletion of one such sequence, conserved noncoding sequence 1 (CNS-1), interferes with the efficient demethylation of Th2 cytokine genes but has little effect on histone modifications in the area. Th2 cells derived from CD4 single-positive (SP) mature thymocytes exhibit more rapid demethylation of CNS-1 and Th2-specific cytokine genes and produce more Th2 cytokines than do Th2 cells derived from CD4-positive peripheral naive T cells. De-repression of the Th1 cytokine IFN-γ was also detected in Th2-primed CD4 SP thymocytes but not in naive T cells. Our results indicate that susceptibility to demethylation determines the efficiency and kinetics of cytokine gene transcription. The extrathymic maturation step undergone by naive T cells suppresses robust and rapid cytokine expression, whereas mature CD4 SP thymocytes maintain a rapid and less-specific cytokine expression profile. Finally, we detected the methyl cytosine binding protein MBD2 at CNS-1 in mature thymocytes, suggesting that this protein may regulate the demethylation of this region.
Steel Factor Enhances Supraoptimal Antigen-Induced IL-6 Production from Mast Cells via Activation of Protein Kinase C-β
Authors: Fehrenbach Kerstin , Lessmann Eva , Zorn Carolin N. , Kuhny Marcel , Grochowy Gordon , Krystal Gerald , Leitges Michael , Huber Michael
Published: June 2009

Ag-triggered mast cell (MC) activation follows a bell-shaped dose-response curve. Reduced activation in response to supraoptimal Ag concentrations is thought to be due to preferential engagement of inhibitory-acting proteins like SHIP1, Lyn, and protein kinase C (PKC)-δ. We show in this study that short-term prestimulation with Steel factor (SF) prevents supraoptimal Ag inhibition, resulting in synergistic MC degranulation and IL-6 secretion. These events are preceded by synergistic phosphorylation/activation of numerous signaling proteins, e.g., Erk, p38, and LAT. However, these effects of prestimulation with SF appear not to be due to reduced engagement of the attenuator SHIP1. Pharmacological analyses suggest that the activation of conventional PKCs is important for this synergy. Specifically, although we found that the conventional PKC inhibitor, Gö6976, likely has some PKC-independent targets in MCs, it led us to further studies that established SF plus Ag-induced IL-6 secretion was severely impaired in PKC-β−/− MCs, but not PKC-α−/− MCs. Thus, PKC-β joins PI3K and Btk as important players in this synergistic MC activation.
Ectodomain Shedding of FLT3 Ligand Is Mediated by TNF-α Converting Enzyme
Authors: Horiuchi Keisuke , Morioka Hideo , Takaishi Hironari , Akiyama Haruhiko , Blobel Carl P. , Toyama Yoshiaki
Published: June 2009

FLT3 ligand (FLT3L) has diverse roles in the hematopoietic system, which include stimulating proliferation of hematopoietic precursors and development of NK cells and dendritic cells. FLT3L is initially synthesized as a membrane-bound protein, which must be cleaved to become a soluble growth factor. However, little is known about the enzyme involved in the proteolytic release of FLT3L. In the current study, we show that shedding of FLT3L is metalloprotease-dependent, and that this proteolytic activity was abolished in fibroblasts lacking TNF-α converting enzyme (TACE) and could be rescued by reintroducing wild-type TACE in these cells. Moreover, we found that cells derived from the thymus of conditional TACE-deficient mice produce less FLT3L, and that serum FLT3L levels in these TACE mutant mice are significantly lower, both after LPS treatment and in the absence of such a challenge, further corroborating the relevance of TACE as FLT3L sheddase in vivo. Considering the involvements of FLT3 and FLT3L in hematopoietic malignancies and stem cell mobilization, the identification of the enzyme involved in FLT3L shedding may have important clinical implications.
Altered Expression of 15-Hydroxyprostaglandin Dehydrogenase in Tumor-Infiltrated CD11b Myeloid Cells: A Mechanism for Immune Evasion in Cancer
Authors: Eruslanov Evgeniy , Kaliberov Sergei , Daurkin Irina , Kaliberova Lyudmila , Buchsbaum Donald , Vieweg Johannes , Kusmartsev Sergei
Published: June 2009

Many cancers are known to produce high amounts of PGE2, which is involved in both tumor progression and tumor-induced immune dysfunction. The key enzyme responsible for the biological inactivation of PGE2 in tissue is NAD+-dependent 15-hydroxyprostaglandin dehydrogenase (15-PGDH). It is well established that cancer cells frequently show down-regulated expression of 15-PGDH, which plays a major role in catabolism of the PGE2. Here we demonstrate that tumor-infiltrated CD11b cells are also deficient for the 15-PGDH gene. Targeted adenovirus-mediated delivery of 15-PGDH gene resulted in substantial inhibition of tumor growth in mice with implanted CT-26 colon carcinomas. PGDH-mediated antitumor effect was associated with attenuated tumor-induced immune suppression and substantially reduced secretion of immunosuppressive mediators and cytokines such as PGE2, IL-10, IL-13, and IL-6 by intratumoral CD11b cells. We show also that introduction of 15-PGDH gene in tumor tissue is sufficient to redirect the differentiation of intratumoral CD11b cells from immunosuppressive M2-oriented F4/80+ tumor-associated macrophages (TAM) into M1-oriented CD11c+ MHC class II-positive myeloid APCs. Notably, the administration of the 15-PGDH gene alone demonstrated a significant therapeutic effect promoting tumor eradication and long-term survival in 70% of mice with preestablished tumors. Surviving mice acquired antitumor T cell-mediated immune response. This study for the first time demonstrates an important role of the 15-PGDH in regulation of local antitumor immune response and highlights the potential to be implemented to enhance the efficacy of cancer therapy and immunotherapy.
The Bcl-2 Family Antagonist ABT-737 Significantly Inhibits Multiple Animal Models of Autoimmunity
Authors: Bardwell Philip D. , Gu Jijie , McCarthy Donna , Wallace Craig , Bryant Shaughn , Goess Christian , Mathieu Suzanne , Grinnell Chris , Erickson Jamie , Rosenberg Saul H. , Schwartz Annette J. , Hugunin Margaret , Tarcsa Edit , Elmore Steven W. , McRae Bradford , Murtaza Anwar , Wang Li Chun , Ghayur Tariq
Published: June 2009

The Bcl-2 family of proteins plays a critical role in controlling immune responses by regulating the expansion and contraction of activated lymphocyte clones by apoptosis. ABT-737, which was originally developed for oncology, is a potent inhibitor of Bcl-2, Bcl-xL, and Bcl-w protein function. There is evidence that Bcl-2–associated dysregulation of lymphocyte apoptosis may contribute to the pathogenesis of autoimmunity and lead to the development of autoimmune diseases. In this study, we report that ABT-737 treatment resulted in potent inhibition of lymphocyte proliferation as measured by in vitro mitogenic or ex vivo Ag-specific stimulation. More importantly, ABT-737 significantly reduced disease severity in tissue-specific and systemic animal models of autoimmunity. Bcl-2 family antagonism by ABT-737 was efficacious in treating animal models of arthritis and lupus. Our results suggest that treatment with a Bcl-2 family antagonist represents a novel and potentially attractive therapeutic approach for the clinical treatment of autoimmunity.
A20 Negatively Regulates T Cell Receptor Signaling to NF-κB by Cleaving Malt1 Ubiquitin Chains
Authors: Düwel Michael , Welteke Verena , Oeckinghaus Andrea , Baens Mathijs , Kloo Bernhard , Ferch Uta , Darnay Bryant G. , Ruland Jürgen , Marynen Peter , Krappmann Daniel
Published: June 2009

The Carma1-Bcl10-Malt1 signaling module bridges TCR signaling to the canonical IκB kinase (IKK)/NF-κB pathway. Covalent attachment of regulatory ubiquitin chains to Malt1 paracaspase directs TCR signaling to IKK activation. Further, the ubiquitin-editing enzyme A20 was recently suggested to suppress T cell activation, but molecular targets for A20 remain elusive. In this paper, we show that A20 regulates the strength and duration of the IKK/NF-κB response upon TCR/CD28 costimulation. By catalyzing the removal of K63-linked ubiquitin chains from Malt1, A20 prevents sustained interaction between ubiquitinated Malt1 and the IKK complex and thus serves as a negative regulator of inducible IKK activity. Upon T cell stimulation, A20 is rapidly removed and paracaspase activity of Malt1 has been suggested to cleave A20. Using antagonistic peptides or reconstitution of Malt1−/− T cells, we show that Malt1 paracaspase activity is required for A20 cleavage and optimal IL-2 production, but dispensable for initial IKK/NF-κB signaling in CD4+ T cells. However, proteasomal inhibition impairs A20 degradation and impedes TCR/CD28-induced IKK activation. Taken together, A20 functions as a Malt1 deubiquitinating enzyme and proteasomal degradation and de novo synthesis of A20 contributes to balance TCR/CD28-induced IKK/NF-κB signaling.
Selective Autoantibody Production against CCL3 Is Associated with Human Type 1 Diabetes Mellitus and Serves As a Novel Biomarker for Its Diagnosis
Authors: Shehadeh Naim , Pollack Shirly , Wildbaum Gizi , Zohar Yaniv , Shafat Itay , Makhoul Reem , Daod Essam , Hakim Fahed , Perlman Rina , Karin Nathan
Published: June 2009

We have recently demonstrated that patients suffering from chronic autoimmune diseases develop an autoantibody response against key mediators that participate in the initiation and progression of these diseases. In this paper, we show that patients with type 1 diabetes mellitus (T1DM), but not those suffering from several other inflammatory autoimmune diseases, display a selective autoantibody titer to a single CC chemokine named CCL3. From the diagnostic point we show that this response could be used as a biomarker for diagnosis of T1DM, a disease that is currently diagnosed by autoantibodies to competitive anti-insulin Abs, islet cell Abs, and glutamic acid decarboxylase Abs. We show that our currently suggested biomarker is more reliable than each of the above alone, including diagnosis of T1DM at its preclinical stage, and could therefore be used as a novel way for diagnosis of T1DM. These Abs were found to be neutralizing Abs. It is possible, though hard to prove, that these Abs participate in the natural regulation of the human disease. Hence, it has previously been shown by others that selective neutralization of CCL3 suppresses T1DM in NOD mice. Theses results together with ours suggest CCL3 as a preferential target for therapy of T1DM.
Differential Expression of Adenosine A3 Receptors Controls Adenosine A2A Receptor-Mediated Inhibition of TLR Responses in Microglia
Authors: van der Putten Céline , Zuiderwijk-Sick Ella A. , van Straalen Linda , de Geus Eveline D. , Boven Leonie A. , Kondova Ivanela , IJzerman Ad P. , Bajramovic Jeffrey J.
Published: June 2009

Microglia activation is a prominent feature in many neuroinflammatory disorders. Unrestrained activation can generate a chronic inflammatory environment that might lead to neurodegeneration and autoimmunity. Extracellular adenosine modulates cellular activation through adenosine receptor (ADORA)-mediated signaling. There are four ADORA subtypes that can either increase (A2A and A2B receptors) or decrease (A1 and A3 receptors) intracellular cyclic AMP levels. The expression pattern of the subtypes thus orchestrates the cellular response to extracellular adenosine. We have investigated the expression of ADORA subtypes in unstimulated and TLR-activated primary rhesus monkey microglia. Activation induced an up-regulation of A2A and a down-regulation of A3 receptor (A3R) levels. The altered ADORA-expression pattern sensitized microglia to A2A receptor (A2AR)-mediated inhibition of subsequent TLR-induced cytokine responses. By using combinations of subtype-specific agonists and antagonists, we revealed that in unstimulated microglia, A2AR-mediated inhibitory signaling was effectively counteracted by A3R-mediated signaling. In activated microglia, the decrease in A3R-mediated signaling sensitized them to A2AR-mediated inhibitory signaling. We report a differential, activation state-specific expression of ADORA in microglia and uncover a role for A3R as dynamically regulated suppressors of A2AR-mediated inhibition of TLR-induced responses. This would suggest exploration of combinations of A2AR agonists and A3R antagonists to dampen microglial activation during chronic neuroinflammatory conditions.
Endotoxin Augmented Antigen-Induced Th1 Cell Trafficking Amplifies Airway Neutrophilic Inflammation
Authors: Mikhak Zamaneh , Farsidjani Alireza , Luster Andrew D.
Published: June 2009

CD4+ Th1 cells play a critical role in orchestrating host defense against pathogens and in the pathogenesis of many immune-mediated diseases. The control of Th1 cell trafficking into sites of infection and inflammation is an important determinant of Th1 cell function. We have previously shown that trafficking of adoptively transferred Ag-specific Th1 cells into the lung following airway Ag challenge depends on CXCR3 expression on Th1 cells and STAT1-inducible CXCR3 ligands in the lung. In this study, we show that LPS alters the mechanisms of Th1 cell recruitment. After a single intranasal dose of LPS, trafficking of adoptively transferred Ag-specific Th1 cell into the lung in response to airway Ag challenges was no longer dependent on CXCR3 and its ligands and instead was mediated through additional Gαi-coupled chemoattractant receptor pathways, including CCR5. In addition, LPS markedly increased the magnitude of Ag-specific Th1 cell homing into the airways following airway Ag challenges. The increased trafficking of Ag-activated Th1 cells, in turn, dramatically amplified LPS-induced airway neutrophilic infiltration by maintaining high levels of the neutrophil active chemokines, KC and MIP-2, through an IFN-γ dependent mechanism. Therefore, LPS increases Ag-specific Th1 cell trafficking into the airways and Ag-specific Th1 cells amplify the airway neutrophilic inflammatory response initiated by LPS. This reciprocal interaction between LPS and Ag-activated Th1 cells represents a collaborative connection between the innate and adaptive arms of the immune system.
Protective Role for Protease-Activated Receptor-2 against Influenza Virus Pathogenesis via an IFN-γ-Dependent Pathway
Authors: Khoufache Khaled , LeBouder Fanny , Morello Eric , Laurent Fabrice , Riffault Sabine , Andrade-Gordon Patricia , Boullier Severine , Rousset Perrine , Vergnolle Nathalie , Riteau Béatrice
Published: June 2009

Protease-activated receptor-2 (PAR2), a receptor highly expressed in the respiratory tract, can influence inflammation at mucosal surfaces. Although the effects of PAR2 in the innate immune response to bacterial infection have been documented, knowledge of its role in the context of viral infection is lacking. We thus investigated the role of PAR2 in influenza pathogenesis in vitro and in vivo. In vitro, stimulation of PAR2 on epithelial cells inhibited influenza virus type A (IAV) replication through the production of IFN-γ. In vivo, stimulation of PAR2 using specific agonists protected mice from IAV-induced acute lung injury and death. This effect correlated with an increased clearance of IAV in the lungs associated with increased IFN- γ production and a decreased presence of neutrophils and RANTES release in bronchoalveolar fluids. More importantly, the protective effect of the PAR2 agonist was totally abrogated in IFN- γ-deficient mice. Finally, compared with wild-type mice, PAR2-deficient mice were more susceptible to IAV infection and displayed more severe lung inflammation. In these mice higher neutrophil counts and increased RANTES concentration but decreased IFN- γ levels were observed in the bronchoalveolar lavages. Collectively, these results showed that PAR2 plays a protective role during IAV infection through IFN-γ production and decreased excessive recruitment of inflammatory cells to lung alveoli.
Increase in ALK1/ALK5 Ratio as a Cause for Elevated MMP-13 Expression in Osteoarthritis in Humans and Mice
Authors: Blaney Davidson Esmeralda N. , Remst Dennis F. G. , Vitters Elly L. , van Beuningen Henk M. , Blom Arjen B. , Goumans Marie-Jose , van den Berg Wim B. , van der Kraan Peter M.
Published: June 2009

During osteoarthritis (OA) chondrocytes show deviant behavior resembling terminal differentiation of growth-plate chondrocytes, characterized by elevated MMP-13 expression. The latter is also a hallmark for OA. TGF-β is generally thought to be a protective factor for cartilage, but it has also displayed deleterious effects in some studies. Recently, it was shown that besides signaling via the ALK5 (activin-like kinase 5) receptor, TGF-β can also signal via ALK1, thereby activating Smad1/5/8 instead of Smad2/3. The Smad1/5/8 route can induce chondrocyte terminal differentiation. Murine chondrocytes stimulated with TGF-β activated the ALK5 receptor/Smad2/3 route as well as the ALK1/Smad1/5/8 route. In cartilage of mouse models for aging and OA, ALK5 expression decreased much more than ALK1. Thus, the ALK1/ALK5 ratio increased, which was associated with changes in the respective downstream markers: an increased Id-1 (inhibitor of DNA binding-1)/PAI-1 (plasminogen activator inhibitor-1) ratio. Transfection of chondrocytes with adenovirus overexpressing constitutive active ALK1 increased MMP-13 expression, while small interfering RNA against ALK1 decreased MMP-13 expression to nondetectable levels. Adenovirus overexpressing constitutive active ALK5 transfection increased aggrecan expression, whereas small interfering RNA against ALK5 resulted in increased MMP-13 expression. Moreover, in human OA cartilage ALK1 was highly correlated with MMP-13 expression, whereas ALK5 correlated with aggrecan and collagen type II expression, important for healthy cartilage. Collectively, we show an age-related shift in ALK1/ALK5 ratio in murine cartilage and a strong correlation between ALK1 and MMP-13 expression in human cartilage. A change in balance between ALK5 and ALK1 receptors in chondrocytes caused changes in MMP-13 expression, thereby causing an OA-like phenotype. Our data suggest that dominant ALK1 signaling results in deviant chondrocyte behavior, thereby contributing to age-related cartilage destruction and OA.
Interactions of α-, β-, and θ-Defensins with Influenza A Virus and Surfactant Protein D
Authors: Doss Mona , White Mitchell R. , Tecle Tesfaldet , Gantz Donald , Crouch Erika C. , Jung Grace , Ruchala Piotr , Waring Alan J. , Lehrer Robert I. , Hartshorn Kevan L.
Published: June 2009

We have reported that the α-defensins human neutrophil peptides (HNP)-1 and HNP-2 neutralize and aggregate influenza A virus (IAV) and promote uptake of IAV by neutrophils. These α-defensins were also shown to bind to surfactant protein (SP)-D and reduce its antiviral activity. In this study, we examined retrocyclin (RC)1 and RC2, humanized versions of the antiviral θ-defensins found in the leukocytes of certain nonhuman primates. RC1 was just as effective as HNP-1–3 in neutralizing IAV, and RC2 and RC101 (an analog of RC1) were more effective. In contrast, human β-defensins (HBDs) showed less neutralizing activity. Human defensins 5 and 6 (mainly produced by intestinal Paneth cells) had viral neutralizing activity similar to HNP-1–3. Like HNP-1–3, RCs induced viral aggregation and promoted the uptake of IAV by neutrophils. We used surface plasmon resonance to evaluate binding of defensins to SP-D. HBDs, HD6, and HNP-4 bound minimally to SP-D. HNP-1–3 and RCs bound SP-D with high affinity; however, unlike HNP-1 and HNP-2, RCs did not inhibit SP-D antiviral activity. HBDs also did not inhibit antiviral activity of SP-D. Given their strong neutralizing activity and compatibility with SP-D, RCs may provide attractive prototypes for designing therapeutics that can prevent or treat respiratory infections caused by IAV.
Gene Disruption Study Reveals a Nonredundant Role for TRIM21/Ro52 in NF-κB-Dependent Cytokine Expression in Fibroblasts
Authors: Yoshimi Ryusuke , Chang Tsung-Hsien , Wang Hongsheng , Atsumi Toru , Morse Herbert C. , Ozato Keiko
Published: June 2009

The tripartite motif (TRIM) family member, TRIM21, is an E3 ubiquitin ligase for IFN regulatory factor (IRF)3 and IRF8 that functions in both innate and acquired immunity. It is also an autoantigen known as Ro52/SS-A. The function of TRIM21 in vivo, however, has remained elusive. We generated Trim21−/− mice with the Trim21 gene replaced by an enhanced GFP (EGFP) reporter. EGFP expression analyses showed that Trim21 was widely expressed in many tissues, with the highest levels in immune cells. Studies of Trim21−/− embryonic fibroblasts demonstrated that TLR-mediated induction of proinflammatory cytokines, including IL-1β, IL-6, TNF-α, and CXCL10, was consistently up-regulated relative to wild-type cells. Reporter analyses demonstrated that TLR-mediated NF-κB activation was higher in Trim21−/− cells than in wild-type cells, most likely accounting for their enhanced cytokine expression. In contrast, functional analyses of immune cells from Trim21−/− mice revealed no abnormalities in their composition or function, even though ubiquitylation of IRF3 and IRF8 was impaired. These results suggested possible redundancies in activities mediated by TRIM21. In keeping with this concept, we found that a number of TRIM family members were up-regulated in Trim21−/− cells. Taken together, these findings demonstrate that TRIM21 plays a previously unrecognized role in the negative regulation of NF-κB-dependent proinflammatory cytokine responses, and suggest that multiple TRIM proteins contribute to the maintenance of functional equilibrium in inflammatory responses, in part through functional redundancy.
Engineering Human IgG1 Affinity to Human Neonatal Fc Receptor: Impact of Affinity Improvement on Pharmacokinetics in Primates
Authors: Yeung Yik Andy , Leabman Maya K. , Marvin Jonathan S. , Qiu Julia , Adams Camellia W. , Lien Samantha , Starovasnik Melissa A. , Lowman Henry B.
Published: June 2009

The pH-dependent binding of Igs to the neonatal FcR (FcRn) plays a critical role in the in vivo homeostasis of IgGs. Modulating the interaction between Fc and FcRn through protein engineering is one method for improving the pharmacokinetics of therapeutic Abs. Recent studies disputed the direct relationship between increasing FcRn affinity and improved pharmacokinetic properties. In this work, we studied the pharmacokinetics of two human IgG1 Fc variants in cynomolgus monkey to further clarify the affinity-pharmacokinetic relationship. First, we report a number of novel Fc point mutations and combination variants, including some with primate-specific FcRn-binding improvements. By studying these variants along with some previously described variants across a wide range of affinities, we discovered a direct correlation of pH 6 affinity improvements with neutral pH improvements, suggesting that all of the tested variants exhibit similar pH dependency in FcRn binding. We then evaluated the pharmacokinetics of variants N434A and N434W, which, respectively, gave ∼4- and 80-fold improvements in pH 6-binding affinity to both human and nonhuman primate FcRn. Surprisingly, clearance of N434W was similar to that of wild type. N434W is the first variant studied in primates that exhibits significant binding to FcRn at pH 7.4, and its clearance substantiates the principle that too much affinity improvement, i.e., beyond that of N434W, does not yield improved pharmacokinetics. In contrast, N434A exhibited a ∼2-fold decrease in clearance in cynomolgus monkey, supporting the notion that modest increases in pH 6 FcRn affinity can result in improved pharmacokinetics in primates.
Scabies Mite Inactivated Serine Protease Paralogs Inhibit the Human Complement System
Authors: Bergström Frida C. , Reynolds Simone , Johnstone Masego , Pike Robert N. , Buckle Ashley M. , Kemp David J. , Fischer Katja , Blom Anna M.
Published: June 2009

Infestation of skin by the parasitic itch mite Sarcoptes scabiei afflicts 300 million people worldwide and there is a need for novel and efficient therapies. We have previously identified a multigene family of serine proteases comprising multiple catalytically inactive members (scabies mite-inactivated protease paralogs (SMIPPs)), which are secreted into the gut of S. scabiei. SMIPPs are located in the mite gut and in feces excreted into the upper epidermis. Scabies mites feed on epidermal protein, including host plasma; consequently, they are exposed to host defense mechanisms both internally and externally. We found that two recombinantly expressed SMIPPs inhibited all three pathways of the human complement system. Both SMIPPs exerted their inhibitory action due to binding of three molecules involved in the three different mechanisms which initiate complement: C1q, mannose-binding lectin, and properdin. Both SMIPPs bound to the stalk domains of C1q, possibly displacing or inhibiting C1r/C1s, which are associated with the same domain. Furthermore, we found that binding of both SMIPPs to properdin resulted in prevention of assembly of the alternative pathway convertases. However, the SMIPPs were not able to dissociate already formed convertases. Immunohistochemical staining demonstrated the presence of C1q in the gut of scabies mites in skin burrows. We propose that SMIPPs minimize complement-mediated gut damage and thus create a favorable environment for the scabies mites.
CXCR4 Expression Functionally Discriminates Centroblasts versus Centrocytes within Human Germinal Center B Cells
Authors: Caron Gersende , Le Gallou Simon , Lamy Thierry , Tarte Karin , Fest Thierry
Published: June 2009

The human germinal center is a highly dynamic structure where B cells conduct their terminal differentiation and traffic following chemokine gradients. The rapidly dividing centroblasts and the nondividing centrocytes represent the two major B cell subsets present in germinal center and also the most common normal counterparts for a majority of lymphomas. CD77 expression was previously associated to proliferating centroblasts undergoing somatic hypermutation, but data from transcriptional studies demonstrate that CD77 is not a reliable marker to discriminate human centroblasts from centrocytes. Herein we were able for the first time to separate these two subpopulations based on the expression of the chemokine receptor CXCR4 allowing their characterization. Phenotypic and functional features were especially explored, giving an accurate definition of CXCR4+ centroblasts compared with CXCR4− centrocytes. We show that CXCR4+ and CXCR4− germinal center B cells present a clear dichotomy in terms of proliferation, transcription factor expression, Ig production, and somatic hypermutation regulation. Microarray analysis identified an extensive gene list segregating these B cells, including highly relevant genes according to previous knowledge. By gene set enrichment analysis we demonstrated that the centroblastic gene expression signature was significantly enriched in Burkitt’s lymphomas. Collectively, our findings show that CXCR4 expression can properly separate human centroblasts from centrocytes and offer now the possibility to have purified normal counterparts of mature B cell-derived malignancies.
Cutting Edge: Primary and Secondary Effects of CD19 Deficiency on Cells of the Marginal Zone
Authors: You Yuying , Zhao Hong , Wang Yue , Carter Robert H.
Published: June 2009

Marginal zone (MZ) B cells are absent in CD19−/− mice. Possible causes include an intrinsic defect in B cells and/or a secondary defect in the extrinsic MZ microenvironment as a result of changes in B cell differentiation in mice lacking CD19. Cells in the MZ also include MZ macrophages (MZM) and MZ dendritic cells (DC). Although CD19 is only expressed on B cells, SIGN-R1+ MZM are absent and CD11c+ MZ DC distribution is abnormal in CD19−/− mice. Adoptively transferred B cells from normal mice are able to reconstitute MZ B cells in CD19−/− mice. In contrast, CD19−/− B cells could not enter the MZ of the normal mice. Furthermore, MZM distribution and MZ DC distribution are restored following MZ B cell reconstitution in CD19−/− mice. Thus, MZ B cells are required for MZM differentiation and MZ DC localization, but the deficiency of MZ B cells in CD19−/− mice is caused by a defect of intrinsic B cell signaling.
Association of FcγRIIa (CD32a) with Lipid Rafts Regulates Ligand Binding Activity
Authors: Bournazos Stylianos , Hart Simon P. , Chamberlain Luke H. , Glennie Martin J. , Dransfield Ian
Published: June 2009

Binding of Igs to myeloid cells via FcR is a key event in the control of innate and acquired immunity. FcγRIIa (CD32a) is a receptor for multivalent IgG expressed predominantly by myeloid cells, and its association with microdomains rich in cholesterol and sphingolipids, termed as lipid rafts, has been reported to be essential for efficient signaling. However, for many myeloid cell types, ligand binding to CD32a is suppressed by as yet undefined mechanisms. In this study, we have examined the role of CD32a-lipid raft interactions in the regulation of IgG binding to CD32a. Disruption of lipid raft structure following depletion or sequestration of membrane cholesterol greatly inhibited CD32a-mediated IgG binding. Furthermore, specific CD32a mutants, which show reduced association with lipid rafts (A224S and C241A), displayed decreased levels of IgG binding compared with wild-type CD32a. In contrast, constitutively lipid raft-associated CD32a (GPI-anchored CD32a) exhibited increased capacity for IgG binding compared with the full-length transmembrane CD32a. Our findings clearly suggest a major role for lipid rafts in the regulation of IgG binding and, more specifically, that suppression of CD32a-mediated IgG binding in myeloid cells is achieved by receptor exclusion from lipid raft membrane microdomains.
Two MHC Class I Molecules Associated with Elite Control of Immunodeficiency Virus Replication, Mamu-B*08 and HLA-B*2705, Bind Peptides with Sequence Similarity
Authors: Loffredo John T. , Sidney John , Bean Alex T. , Beal Dominic R. , Bardet Wilfried , Wahl Angela , Hawkins Oriana E. , Piaskowski Shari , Wilson Nancy A. , Hildebrand William H. , Watkins David I. , Sette Alessandro
Published: June 2009

HLA-B27- and -B57-positive HIV-infected humans have long been associated with control of HIV replication, implying that CD8+ T cell responses contribute to control of viral replication. In a similar fashion, 50% of Mamu-B*08-positive Indian rhesus macaques control SIVmac239 replication and become elite controllers with chronic-phase viremia <1000 viral RNA copies/ml. Interestingly, Mamu-B*08-restricted SIV-derived epitopes appeared to match the peptide binding profile for HLA-B*2705 in humans. We therefore defined a detailed peptide-binding motif for Mamu-B*08 and investigated binding similarities between the macaque and human MHC class I molecules. Analysis of a panel of ∼900 peptides revealed that despite substantial sequence differences between Mamu-B*08 and HLA-B*2705, the peptide-binding repertoires of these two MHC class I molecules share a remarkable degree of overlap. Detailed knowledge of the Mamu-B*08 peptide-binding motif enabled us to identify six additional novel Mamu-B*08-restricted SIV-specific CD8+ T cell immune responses directed against epitopes in Gag, Vpr, and Env. All 13 Mamu-B*08-restricted epitopes contain an R at the position 2 primary anchor and 10 also possess either R or K at the N terminus. Such dibasic peptides are less prone to cellular degradation. This work highlights the relevance of the Mamu-B*08-positive SIV-infected Indian rhesus macaque as a model to examine elite control of immunodeficiency virus replication. The remarkable similarity of the peptide-binding motifs and repertoires for Mamu-B*08 and HLA-B*2705 suggests that the nature of the peptide bound by the MHC class I molecule may play an important role in control of immunodeficiency virus replication.
The Development and Function of Regulatory B Cells Expressing IL-10 (B10 Cells) Requires Antigen Receptor Diversity and TLR Signals
Authors: Yanaba Koichi , Bouaziz Jean-David , Matsushita Takashi , Tsubata Takeshi , Tedder Thomas F.
Published: June 2009

Autoimmunity and inflammation are controlled in part by regulatory B cells, including a recently identified IL-10-competent CD1dhighCD5+ B cell subset termed B10 cells that represents 1–3% of adult mouse spleen B cells. In this study, pathways that influence B10 cell generation and IL-10 production were identified and compared with previously described regulatory B cells. IL-10-competent B cells were predominantly CD1dhighCD5+ in adult spleen and were the prevalent source of IL-10, but not other cytokines. B10 cell development and/or maturation in vivo required Ag receptor diversity and intact signaling pathways, but not T cells, gut-associated flora, or environmental pathogens. Spleen B10 cell frequencies were significantly expanded in aged mice and mice predisposed to autoimmunity, but were significantly decreased in mouse strains that are susceptible to exogenous autoantigen-induced autoimmunity. LPS, PMA, plus ionomycin stimulation in vitro for 5 h induced B10 cells to express cytoplasmic IL-10. However, prolonged LPS or CD40 stimulation (48 h) induced additional adult spleen CD1dhighCD5+ B cells to express IL-10 following PMA plus ionomycin stimulation. Prolonged LPS or CD40 stimulation of newborn spleen and adult blood or lymph node CD1dlow and/or CD5− B cells also induced cytoplasmic IL-10 competence in rare B cells, with CD40 ligation uniformly inducing CD5 expression. IL-10 secretion was induced by LPS signaling through MyD88-dependent pathways, but not following CD40 ligation. LPS stimulation also induced rapid B10 cell clonal expansion when compared with other spleen B cells. Thereby, both adaptive and innate signals regulate B10 cell development, maturation, CD5 expression, and competence for IL-10 production.
Culling of Activated CD4 T Cells during Typhoid Is Driven by Salmonella Virulence Genes
Authors: Srinivasan Aparna , Nanton Minelva , Griffin Amanda , McSorley Stephen J.
Published: June 2009

Pathogen-specific CD4 T cells are activated within a few hours of oral Salmonella infection and are essential for protective immunity. However, CD4 T cells do not participate in bacterial clearance until several weeks after infection, suggesting that Salmonella can inhibit or evade CD4 T cells that are activated at early time points. Here, we describe the progressive culling of initially activated CD4 T cells in Salmonella-infected mice. Loss of activated CD4 T cells was independent of early instructional programming, T cell precursor frequency, and Ag availability. In contrast, apoptosis of Ag-specific CD4 T cells was actively induced by live bacteria in a process that required Salmonella pathogenicity island-2 and correlated with increased expression of PD-L1. These data demonstrate efficient culling of initially activated Ag-specific CD4 cells by a microbial pathogen and document a novel strategy for bacterial immune evasion.
Cutting Edge: γδ Intraepithelial Lymphocytes of the Small Intestine Are Not Biased toward Thymic Antigens
Authors: Jensen Kirk D. C. , Shin Sunny , Chien Yueh-hsiu
Published: June 2009

γδ Τ cells, together with αβ Τ cells, are abundantly present in the epithelial layer of the small intestine (IEL) and are essential for the host’s first line of defense. Whether or not γδ IELs, like αβ IELs, are derived from thymocytes that encounter self-Ags in the thymus is unclear. In this study, we report that a natural population of γδ T cells that are specific for the nonclassical MHC class I molecules T10 and T22 are present in the IEL compartment of mice that do not express T10/T22. Furthermore, the small intestinal homing receptor CCR9 is preferentially expressed on γδ thymocytes that have yet to encounter a ligand, and γδ thymocytes with high affinity for self-ligand are CCR9low. These observations suggest that the Ag-specific repertoire of γδ IELs is not biased toward thymic Ags. Instead, γδ IELs appear suited to respond to novel Ags revealed in pathological settings.
Enhanced Airway Inflammation and Remodeling in Adenosine Deaminase-Deficient Mice Lacking the A2B Adenosine Receptor
Authors: Zhou Yang , Mohsenin Amir , Morschl Eva , Young Hays W. J. , Molina Jose G. , Ma Wenbin , Sun Chun-Xiao , Martinez-Valdez Hector , Blackburn Michael R.
Published: June 2009

Adenosine is a signaling nucleoside that is generated in response to cellular injury and orchestrates the balance between tissue protection and the progression to pathological tissue remodeling. Adenosine deaminase (ADA)-deficient mice develop progressive airway inflammation and remodeling in association with adenosine elevations, suggesting that adenosine can promote features of chronic lung disease. Furthermore, pharmacological studies in ADA-deficient mice demonstrate that A2BR antagonism can attenuate features of chronic lung disease, implicating this receptor in the progression of chronic lung disease. This study examines the contribution of A2BR signaling in this model by generating ADA/A2BR double-knockout mice. Our hypothesis was that genetic removal of the A2BR from ADA-deficient mice would lead to diminished pulmonary inflammation and damage. Unexpectedly, ADA/A2BR double-knockout mice exhibited enhanced pulmonary inflammation and airway destruction. Marked loss of pulmonary barrier function and excessive airway neutrophilia are thought to contribute to the enhanced tissue damage observed. These findings support an important protective role for A2BR signaling during acute stages of lung disease.
Genome-Wide Identification of Long Noncoding RNAs in CD8+ T Cells
Authors: Pang Ken C. , Dinger Marcel E. , Mercer Tim R. , Malquori Lorenzo , Grimmond Sean M. , Chen Weisan , Mattick John S.
Published: June 2009

Previous research into the molecular mechanisms that underlie Ag-specific CD8+ T cell differentiation and function has largely focused on the role of proteins. However, it is now apparent that the mammalian genome expresses large numbers of long (>200 nt) nonprotein-coding RNAs (ncRNAs), and there is increasing evidence that these RNAs have important regulatory functions, particularly in the regulation of epigenetic processes underpinning cell differentiation. In this study, we show that CD8+ T cells express hundreds of long ncRNAs, many of which are lymphoid-specific and/or change dynamically with lymphocyte differentiation or activation. Numerous ncRNAs surround or overlap immunologically important protein-coding genes and can be predicted to function via a range of regulatory mechanisms. The overlap of many long ncRNAs expressed in CD8+ T cells with microRNAs and small interfering RNAs further suggests that long ncRNAs may be processed into and exert their effects via smaller functional species. Finally, we show that the majority of long ncRNAs expressed in CD8+ T cells harbor signatures of evolutionary conservation, secondary structures, and/or regulated promoters, further supporting their functionality. Taken together, our findings represent the first systematic discovery of long ncRNAs expressed in CD8+ T cells and suggest that many of these transcripts are likely to play a role in adaptive immunity.
Analogous Interactions in Initiating Complexes of the Classical and Lectin Pathways of Complement
Authors: Phillips Anna E. , Toth Julia , Dodds Alister W. , Girija Umakhanth Venkatraman , Furze Christopher M. , Pala Eleni , Sim Robert B. , Reid Kenneth B. M. , Schwaeble Wilhelm J. , Schmid Ralf , Keeble Anthony H. , Wallis Russell
Published: June 2009

The classical and lectin pathways of complement activation neutralize pathogens and stimulate key immunological processes. Both pathways are initiated by collagen-containing, soluble pattern recognition molecules associated with specific serine proteases. In the classical pathway, C1q binds to Ab-Ag complexes or bacterial surfaces to activate C1r and C1s. In the lectin pathway, mannan-binding lectin and ficolins bind to carbohydrates on pathogens to activate mannan-binding lectin-associated serine protease 2. To characterize the interactions leading to classical pathway activation, we have analyzed binding between human C1q, C1r, and C1s, which associate to form C1, using full-length and truncated protease components. We show that C1r and C1s bind to C1q independently. The CUB1-epidermal growth factor fragments contribute most toward binding, but CUB2 of C1r, but not of C1s, is also important. Each C1rs tetramer presents a total of six binding sites, one for each of the collagenous domains of C1q. We also demonstrate that subcomponents of the lectin and classical pathways cross-interact. Thus, although the stoichiometries of complexes differ, interactions are analogous, with equivalent contacts between recognition and protease subcomponents. Importantly, these new data are contrary to existing models of C1 and enable us to propose a new model using mannan-binding lectin-mannan-binding lectin-associated serine protease interactions as a template.
La fabrique de l’événement littéraire : l’exemple de La Vie mode d’emploi
Authors: Bertelli Dominique
Published: June 2009

Résumé Récusant toute définition de l’œuvre comme une essence donnée une fois pour toutes, la recherche présentée dans cet article participe à l’analyse de la production de la valeur littéraire à partir de l’identification de quelques dimensions de ce qui fait un événement littéraire. Loin d’opposer l’espace littéraire et l’espace médiatique, l’auteur analyse la façon dont se tissent ces deux modalités d’invention du fait littéraire, à partir des stratégies auctoriales et éditoriales, ainsi que des médiations opérées par la collection, les formes de l’œuvre, le processus de parution, la construction de la figure auctoriale. L’analyse porte sur le roman de Georges Perec La vie mode d’emploi . Cf. sur ce sujet « La valeur de la médiation littéraire », Communication & langages , n° 150, 2006.
Contraceptive Method Use Among a Population-Based Cohort During the South Carolina Choose Well Initiative
Authors: Hale Nathan , Lee Jusung , de Jong Jordan , Smith Michael G. , Khoury Amal J.
Published: April 2024

Importance

Evaluating the impact of statewide contraceptive access initiatives is necessary for informing health policy and practice.

Objective

To examine changes in contraceptive method use among a cohort of women of reproductive age in South Carolina during the Choose Well contraceptive access initiative.

Design, Setting, and Participants

In this cohort study, baseline data from the initial Statewide Survey of Women administered from October 1, 2017, to April 30, 2018, to a probability-based sample of women of reproductive age in South Carolina and a peer state (Alabama) were linked with 3 follow-up surveys given in 2019, 2020, and 2021. Responses about contraception use from the initial survey were compared with responses across follow-up surveys using the regression-based differences-in-differences method. Data analysis was performed from October 2023 to February 2024.

Exposure

The South Carolina Choose Well contraceptive access initiative seeks to fill contraceptive access gaps and increase provision of a full range of contraceptive methods through engagement with a wide range of health care organizations across the state.

Main Outcomes and Measures

Changes in contraceptive method use, including long-acting reversible contraception (LARC), intrauterine devices (IUDs), implants, short-acting hormonal injection, and barrier or other methods between the baseline survey (2017-2018) and 3 subsequent surveys (2019-2021).

Results

A total of 1344 female participants (mean [SD] age, 34 [7] years) completed the first survey (667 in Alabama and 677 in South Carolina). Use of LARC significantly increased in South Carolina (119 [17.6%] to 138 [21.1%]) compared with Alabama (120 [18.0%] to 116 [18.1%]; P = .004). Use of IUDs increased in South Carolina (95 [14.0%] to 114 [17.4%]) compared with Alabama (92 [13.8%] to 102 [15.9%]; P = .003). These associations persisted in the adjusted analysis, with a significant increase in the odds of LARC (adjusted odds ratio, 1.24; 95% CI, 1.06-1.44) and IUD (adjusted odds ratio, 1.19; 95% CI, 1.06-1.32) use at follow-up in South Carolina compared with Alabama.

Conclusions and Relevance

In this cohort study of 1344 participants, increases in the use of IUDs in South Carolina were noted after the implementation of the South Carolina Choose Well initiative that were not observed in a peer state with no intervention. Our findings may provide support in favor of statewide contraceptive access initiatives and their role in promoting access to reproductive health services.