bluuebunny/crossref_metadata_2025_split huggingface dataset:
Absence of L-Selectin Delays Mucosal B Cell Responses in Nonintestinal Effector Tissues
Authors: Csencsits Keri L. , Pascual David W. 
Published: April 2014

Abstract
Previous studies suggest that lymphocyte trafficking to head and neck lymph nodes, also referred to as cranial-, oral-, nasal-associated lymphoid tissue (CONALT), is L-selectin (L-Sel) dependent, despite coexpression of α4β7, resulting in their marked reduction in L-Sel-deficient (L-Sel−/−) mice. Consequently, early phase (16 days) Ab responses to cholera toxin (CT) are diminished. The following studies reveal that lack of mucosal effector responses is not caused by loss of inductive immune responses in the L-Sel−/− CONALT. Indeed, there was an increased accumulation of total IgA, but not Ag-specific IgA Ab-forming cells (AFC) in L-Sel−/− CONALT. This increased accumulation was not evident in L-Sel+/+ CONALT. Identification of lymphocyte-homing receptors on L-Sel−/− and L-Sel+/+ CONALT lymphocytes revealed no significant differences in expression of α4β7, which might contribute to lymphocyte homing in the absence of L-Sel. Studies of CONALT responses during the late phase (6 wk post-intranasal immunization) revealed the number of lymphocytes recovered from L-Sel−/− CONALT was less than L-Sel+/+ CONALT; however, L-Sel−/− CT-specific and total AFC did not vary from 16-day responses, suggesting a defect in CT-specific B cell export. No significant differences in α4β7 expression between L-Sel−/− and L-Sel+/+ CONALT were noted. Yet, these increases in CONALT AFC correlated with restoration of immunity in L-Sel−/− nasal passages and reproductive tracts.
Peptide-Independent Folding and CD8αα Binding by the Nonclassical Class I Molecule, Thymic Leukemia Antigen
Authors: Weber Dominique A. , Attinger Antoine , Kemball Christopher C. , Wigal Jerrod L. , Pohl Jan , Xiong Yi , Reinherz Ellis L. , Cheroutre Hilde , Kronenberg Mitchell , Jensen Peter E. 
Published: April 2014

AbstractThe nonclassical class I molecule, thymic leukemia (TL), has been shown to be expressed on intestinal epithelial cells and to interact with CD8+ intraepithelial T lymphocytes. We generated recombinant soluble TL (T18d) H chains in bacteria as inclusion bodies and refolded them with β2-microglobulin in the presence or absence of a random peptide library. Using a mAb, HD168, that recognizes a conformational epitope on native TL molecules, we observed that protein folds efficiently in the absence of peptide. Circular dichroism analysis demonstrated that TL molecules have structural features similar to classical class I molecules. Moreover, thermal denaturation experiments indicated that the melting temperature for peptide-free TL is similar to values reported previously for conventional class I-peptide complexes. Our results also show that CD8αα binding is not dependent on either TL-associated peptide or TL glycosylation.
Differential Regulation of IL-12 and IL-10 Gene Expression in Macrophages by the Basic Leucine Zipper Transcription Factor c-Maf Fibrosarcoma
Authors: Cao Shanjin , Liu Jianguo , Chesi Marta , Bergsagel Peter Leif , Ho I-Cheng , Donnelly Raymond P. , Ma Xiaojing 
Published: April 2014

AbstractIL-12 is a principal activator of both innate and adaptive immunity against infectious agents and malignancies. Regulation of proinflammatory IL-12 gene expression in phagocytes by the anti-inflammatory cytokine IL-10 represents a major homeostatic process underlying host-pathogen and host-self interactions. Delineation of the signaling pathway of IL-10 is crucial to the understanding of immunological regulatory networks. In this study, we report that IL-10 and c-musculoaponeurotic fibrosarcoma (Maf) induce their mutual expression in inflammatory macrophages. We demonstrate that c-Maf is one of the physiological mediators of IL-10’s immunosuppressive activities. When overexpressed, c-Maf selectively inhibits transcriptional activation of IL-12 p40 and p35 genes while potently activating IL-10 and IL-4 expression, potentially contributing to the development of a state of anti-inflammation and dichotomy of immunologic polarization. c-Maf induces changes in nuclear DNA-binding activities at multiple sites including the ets, GA-12, NF-κB, C/EBP, and AP-1 elements. Nonetheless, the essential c-Maf-responsive element appears to be located elsewhere. Inhibition of IL-12 p40 gene expression by c-Maf requires the N-terminal transactivation domain, suggesting an indirect mechanism of transcriptional inhibition involving the induction of an unidentified repressor. In c-Maf-deficient murine macrophages, IL-10 production is impaired. However, IL-10-mediated inhibition of IL-12 production remains intact, indicating the existence of alternative mediators in the absence of c-Maf, consistent with the observation that a functional AP-1 is required for this pathway.
Small Interfering RNA-Mediated Gene Silencing in T Lymphocytes
Authors: McManus Michael T. , Haines Brian B. , Dillon Christopher P. , Whitehurst Charles E. , van Parijs Luk , Chen Jianzhu , Sharp Phillip A. 
Published: April 2014

Abstract
Introduction of small interfering RNAs (siRNAs) into a cell can cause a specific interference of gene expression known as RNA interference (RNAi). However, RNAi activity in lymphocytes and in normal primary mammalian cells has not been thoroughly demonstrated. In this report, we show that siRNAs complementary to CD4 and CD8α specifically reduce surface expression of these coreceptors and their respective mRNA in a thymoma cell line model. We show that RNAi activity is only caused by a subset of siRNAs complementary to the mRNA target and that ineffective siRNAs can compete with effective siRNAs. Using primary differentiated T lymphocytes, we provide the first evidence of siRNA-mediated RNAi gene silencing in normal nontransformed somatic mammalian lymphocytes.
Involvement of Classical and Novel Protein Kinase C Isoforms in the Response of Human Vγ9Vδ2 T Cells to Phosphate Antigens
Authors: Cipriani Barbara , Knowles Heather , Chen Lanfen , Battistini Luca , Brosnan Celia F. 
Published: April 2014

AbstractHuman γδ T cells expressing the Vγ9Vδ2 gene segments are activated polyclonally by phosphoantigens found on a wide variety of pathogenic organisms. After ligand exposure, Vγ9Vδ2 T cells proliferate and rapidly secrete large amounts of cytokines and chemokines that contribute to the innate immune response to these pathogens. Neither APCs nor costimulatory molecules are required. In this study we examined whether these phosphoantigens activate protein kinase Cθ (PKCθ). This novel PKC isoform is essential for Ag signaling through the αβ TCR in a costimulation-dependent fashion. The results showed that isopentenyl pyrophosphate (IPP), a soluble phospholigand released by mycobacteria, led to the rapid and persistent activation of PKCθ in γδ T cells, as determined by evidence of translocation and phosphorylation. In contrast, no ligand-dependent response was detected for PKCα/β or PKCδ. Using the inhibitors Gö6976 and rottlerin, a role for both conventional and novel PKC isoforms in IPP-induced proliferation, CD25 expression, and cytokine and chemokine production was demonstrated. Gel-shift assays indicated that the transcription factors NF-κB and AP-1 were downstream targets of PKC activation. IPP also induced the rapid and persistent phosphorylation of extracellular signal-regulated kinases 1 and 2, p38 mitogen-activated kinase, and stress-activated kinase/c-Jun N-terminal kinase, but only an inhibitor of conventional PKCs blocked these responses. We conclude that the γδ T cell response to phosphoantigens is regulated by both novel and conventional PKC isoforms, with PKCθ being more responsive to ligand stimulation and PKCα/β to growth-factor availability.
The Protective Immune Response to Heat Shock Protein 60 ofHistoplasma capsulatumIs Mediated by a Subset of Vβ8.1/8.2+ T Cells
Authors: Scheckelhoff Mark , Deepe George S. 
Published: April 2014

AbstractImmunization with recombinant heat shock protein 60 (rHsp60) from Histoplasma capsulatum or a region of the protein designated fragment 3 (F3) confers protection from a subsequent challenge in mice. To determine the T cell repertoire involved in the response to Hsp60, T cell clones from C57BL/6 mice immunized with rHsp60 were generated and examined for Vβ usage by flow cytometry and RT-PCR. Vβ8.1/8.2+ T cells were preferentially expanded; other clones bore Vβ4, -6, or -11. When Vβ8.1/8.2+ cells were depleted in mice, Vβ4+ T cell clones were almost exclusively isolated. Measurement of cytokine production demonstrated that nine of 16 Vβ8.1/8.2+ clones were Th1, while only three of 13 non-Vβ8.1/8.2+ clones were Th1. In mice immunized with rHsp60, depletion of Vβ8.1/8.2+, but not Vβ6+ plus Vβ7+, T cells completely abolished the protective efficacy of Hsp60 to lethal and sublethal challenges. Examination of the TCR revealed that a subset of Vβ8.1/2+ clones that produced IFN-γ and were reactive to F3 shared a common CDR3 sequence, DGGQG. Transfer of these T cell clones into TCR α/β−/− or IFN-γ−/− mice significantly improved survival, while transfer of other Vβ8.1/8.2+ clones that were F3 reactive but were Th2 or clones that were not reactive to F3 but were Th1 did not confer protection. These data indicate that a distinct subset of Vβ8.1/8.2+ T cells is crucial for the generation of a protective response to rHsp60.
A Unique Mechanism for Innate Cytokine Promotion of T Cell Responses to Viral Infections
Authors: Pien Gary C. , Nguyen Khuong B. , Malmgaard Lene , Satoskar Abhay R. , Biron Christine A. 
Published: April 2014

AbstractThe kinetics of CD8 T cell IFN-γ responses as they occur in situ are defined here during lymphocytic choriomeningitis virus (LCMV) infections, and a unique mechanism for the innate cytokines IFN-αβ and IL-18 in promoting these responses is defined. Infections of mice with Armstrong or WE strains of LCMV induced an unexpectedly early day 4 IFN-γ response detectable in serum samples and spleen and liver homogenates. Production of IFN-γ was MHC class I/CD8 dependent, but did not require IL-12, NK cells, TCR-γδ T cells, MHC class II, or CD4 T cells. Peak response required specific Ag recognition, as administration of antagonist peptide partially impaired day 4 IFN-γ induction, and viral peptide stimulation enhanced CD8 T cell IFN-γ expression in culture. The IFN-γ response was associated with IL-18 and IFN-αβ expression. Furthermore, both factors augmented peptide-driven IFN-γ production in culture, and mice lacking IL-18 or IFN-αβ functions had reduced day 4 IFN-γ. Collectively, these results demonstrate that during viral infections, there is a dramatic in vivo CD8 T cell response preceding maximal expansion of these cells, and that the mechanism supporting this response is dependent on endogenous innate cytokines. Because stimulation by microbial products is linked to innate cytokine expression, the studies also suggest a pathway for precisely limiting T cell functions to times of need.
Development of Inflammation in Proteoglycan-Induced Arthritis Is Dependent on FcγR Regulation of the Cytokine/Chemokine Environment
Authors: Kaplan Charles D. , O’Neill Shannon K. , Koreny Tamas , Czipri Matyas , Finnegan Alison 
Published: April 2014

AbstractFcγRs are specialized cell surface receptors that coordinately regulate immune responses. Although FcγR expression is a prerequisite for the development of several immune complex-mediated diseases, the mechanism responsible for FcγR-dependent regulation in autoimmunity remains unclear. Therefore, we assessed FcγR-dependent regulation of inflammation in proteoglycan-induced arthritis (PGIA) using FcγR−/− mice. FcγRIIb−/− mice developed arthritis at an earlier time point and with a greater severity than wild-type (WT) mice. In γ-chain−/− (FcγRI−/− and FcγRIII−/−) mice, no clinical or histological evidence of inflammation was observed. Exacerbation of arthritis in FcγRIIb−/− mice correlated with enhanced PG-specific Ab production, but did not significantly affect PG-specific T cell priming. In γ-chain−/− mice, the absence of arthritis did not correlate with serum Ab responses, as PG-specific Ab production was normal. Although PG-specific T cell proliferation was diminished, spleen cells from γ-chain−/− mice successfully adoptively transferred arthritis into SCID mice. Our studies indicated that the mechanism responsible for FcγR regulation of PGIA development was at the level of inflammatory cytokine and β-chemokine expression within the joint. FcγRIIb regulated the development of PGIA by controlling the initiation of cytokine and chemokine expression within the joint before the onset of arthritis, whereas the expression of FcγRI and or FcγRIII controlled cytokine and chemokine expression late in the development of PGIA during the onset of disease. These results suggest that FcγRs are critical for the development of inflammation during PGIA, possibly by maintaining or enhancing inflammatory cytokine and β-chemokine production.
Enhanced Recruitment of Th2 and CLA-Negative Lymphocytes by the S128R Polymorphism of E-Selectin
Authors: Rao Ravi M. , Haskard Dorian O. , Landis R. Clive 
Published: April 2014

AbstractE-selectin is a cytokine-inducible endothelial cell adhesion molecule that binds a restricted population of T lymphocytes consisting of Th1 memory cells bearing the cutaneous lymphocyte Ag (CLA). A serine to arginine (S128R) polymorphism in E-selectin has been reported at increased frequency in patients with systemic lupus erythematosus and atherosclerosis. Here we tested the hypothesis that the S128R substitution may contribute to increased vascular disease by altering the number and/or phenotype of lymphocytes interacting with E-selectin under shear flow. We observed that CHO cell monolayers transfected with S128R recruited significantly greater numbers of unfractionated lymphocytes than monolayers expressing an equivalent density of wild-type (WT) E-selectin. Depletion of the CLA+ subpopulation or generation of CLA− lymphoblasts abolished rolling and arrest on WT E-selectin, but left a residual population that interacted with S128R. Generation of Th subsets revealed preferential interaction of Th0 and Th2, but not Th1, cells with S128R compared with WT. However, only T cells of a memory phenotype interacted with S128R, since neither monolayer supported rolling of CD45RA+ cells. Our results demonstrate that the S128R polymorphism extends the range of lymphocytes recruited by E-selectin, which may provide a mechanistic link between this polymorphism and vascular inflammatory disease.
A Comparison of Reactive Oxygen Species Generation by Rat Peritoneal Macrophages and Mast Cells Using the Highly Sensitive Real-Time Chemiluminescent Probe Pholasin: Inhibition of Antigen-Induced Mast Cell Degranulation by Macrophage-Derived Hydrogen Peroxide
Authors: Swindle Emily J. , Hunt John A. , Coleman John W. 
Published: April 2014

Abstract
Mast cells and macrophages live in close proximity in vivo and reciprocally regulate one another’s function in various ways. Although activated macrophages possess a powerful reactive oxygen species (ROS) generating system, there is conflicting evidence regarding whether mast cells can produce ROS. We used the highly sensitive real-time chemiluminescent probe Pholasin to examine ROS release by peritoneal macrophages and mast cells isolated from OVA-sensitized rats. Macrophages stimulated with PMA (0.8 μM) or ionomycin (1 μM), but not OVA (1 μg/ml), released high-level ROS, levels of which peaked after 3–7 min and declined to baseline levels within 1 h. Superoxide was identified as the major ROS species induced by PMA but not by ionomycin. In contrast, purified mast cells stimulated with PMA released low-level ROS, which was entirely due to the contaminating (2%) macrophages, and did not release any detectable ROS in response to ionomycin or OVA at concentrations that induced degranulation. Stimulation of mixed cell populations with PMA to induce macrophage ROS release led to 50% inhibition of serotonin release from mast cells stimulated 5 min later with OVA. The PMA-induced inhibitory factor was identified as hydrogen peroxide. In conclusion, activated rat peritoneal macrophages but not mast cells produce ROS, and macrophage-derived hydrogen peroxide inhibits mast cell degranulation. The latter could be an important mechanism whereby phagocytic cells regulate mast cell activation and promote resolution of IgE-mediated inflammation.
Toll-Like Receptor 4 and Toll-IL-1 Receptor Domain-Containing Adapter Protein (TIRAP)/Myeloid Differentiation Protein 88 Adapter-Like (Mal) Contribute to Maximal IL-6 Expression in Macrophages
Authors: Schilling Dagmar , Thomas Karen , Nixdorff Kathryn , Vogel Stefanie N. , Fenton Matthew J. 
Published: April 2014

AbstractPrevious studies have shown that engagement of Toll-like receptors (TLR) 2 and 4 can induce macrophages to express a variety of proinflammatory cytokines. We have recently demonstrated that TLR2 agonists poorly induce a subset of TLR4-inducible proinflammatory genes (e.g., inducible protein (IP)-10, inducible NO synthase (iNOS), monocyte chemoattractant protein-5, IL-12p40), due in part to differential activation of IFN-β production and phosphorylation of the transcription factor STAT1. TLR4, but not TLR2, agonists can induce IFN-β expression via a mechanism that requires the adapter protein Toll-IL-1R domain-containing adapter protein (TIRAP)/myeloid differentiation protein 88 (MyD88) adapter-like (Mal), but not the adapter protein MyD88. Thus, the failure of TLR2 agonists to induce STAT1-dependent genes results, in part, from their failure to induce the expression of IFN-β. In this study, we show that IL-6 expression is also preferentially induced by activation of TLR4. TLR4-dependent induction of IL-6 expression did require Toll-IL-1R domain-containing adapter protein (TIRAP)/MyD88 adapter-like (Mal), but unlike iNOS and IP-10, it did not require the expression of IFN-β. Although exogenous IFN-β and IFN-γ could synergize with TLR2 agonists to restore high levels of iNOS expression and NO production, these IFNs could not synergize with TLR2 agonists to induce high levels of IL-6. Similarly, neutralizing anti-IFN Abs could block iNOS gene expression in LPS-stimulated murine macrophages, whereas these Abs had little effect on IL-6 gene expression in these cells. Together, these studies demonstrate that IL-6, like iNOS and IP-10, is differentially expressed in macrophages stimulated via TLR2 vs TLR4, although these differences appear to arise from distinct signaling mechanisms.
Adhesion of B Cell Lines to Endothelial Cells from Human Lymphoid Tissue Modulates Tyrosine Phosphorylation and Endothelial Cell Activation
Authors: Reyes Lilian I. , Escobar Paula , Bono María R. , Rosemblatt Mario 
Published: April 2014

AbstractThrough the production of cytokines and growth factors the endothelium of secondary lymphoid organs plays a crucial role in controlling lymphocyte migration to the lymphoid microenvironment, an essential step in the initiation of the immune response. Here we demonstrate that direct contact of B cell lines with tonsil-derived human endothelial cells resulted in changes in the phosphorylation state of endothelial cells, causing their functional activation. We found a rapid (&lt;15-s) and transient dephosphorylation, followed by a rapid rephosphorylation of tyrosine residues of the focal adhesion kinase, paxillin, and ERK2. Maximal rephosphorylation occurred after 15–30 min of B cell contact. Preincubation of lymphoid B cells with an adhesion-blocking Ab directed against α4β1 integrin abrogated adhesion-mediated changes of endothelial cell tyrosine phosphorylation, suggesting that cell contact was essential. Similar patterns of tyrosine phosphorylation, but with slightly different kinetics were induced after cross-linking of β1 integrin or CD40 on endothelial cells. Functional activation of endothelial cells by B cell adhesion was confirmed by the production of IL-6, IL-8, monocyte chemoattractant protein-1, M-CSF, and macrophage inflammatory protein-1β mRNA. However, direct cross-linking of β1 integrin and CD40 failed to accomplish the same functional activation. These data indicate that direct contact of lymphoid B cells with the endothelium from lymphoid tissue induce endothelial cell signaling, resulting in chemokine and cytokine production. This phenomenon may provide a mechanism for the remodeling of the endothelium from lymphoid tissues, thus contributing to the free migration of lymphocytes and other cells into the lymphoid organs.
Selective Eosinophil Adhesion to Fibroblast Via IFN-γ-Induced Galectin-9
Authors: Asakura Hirofumi , Kashio Yumiko , Nakamura Kazuhiro , Seki Masako , Dai Shuyan , Shirato Yukako , Abedin Mohammad J. , Yoshida Naoko , Nishi Nozomu , Imaizumi Tadaatsu , Saita Naoki , Toyama Yoshihiro , Takashima Hitoshi , Nakamura Takanori , Ohkawa Motoomi , Hirashima Mitsuomi 
Published: April 2014

AbstractAmong galectin family members, galectin-9 was first described as a potent eosinophil chemoattractant derived from Ag-stimulated T cells. In the present study a role of galectin-9 in the interaction between eosinophils and fibroblasts was investigated using a human lung fibroblast cell line, HFL-1. RT-PCR, real-time PCR, and Western blot analyses revealed that both galectin-9 mRNA and protein in HFL-1 cells were up-regulated by IFN-γ stimulation. On the one hand, IL-4, known as a Th2 cytokine, did not affect the galectin-9 expression in HFL-1 cells. We further confirmed that IFN-γ up-regulated the expression of galectin-9 in primary human dermal fibroblasts. Flow cytometric analysis revealed that IFN-γ up-regulated surface galectin-9 expression on HFL-1 cells. Stimulation of HFL-1 cells with IFN-γ up-regulated adhesion of eosinophils, but not neutrophils, to HFL-1 cells. This adherence of eosinophils to HFL-1 cells was inhibited by both lactose and anti-galectin-9 Ab. These findings demonstrate that IFN-γ-induced galectin-9 expression in fibroblasts mediates eosinophil adhesion to the cells, suggesting a crucial role of galectin-9 in IFN-γ-stimulated fibroblasts as a physiological modulator at the inflammatory sites.
Bax is Crucial for IFN-γ-Induced Resolution of Allergen- Induced Mucus Cell Metaplasia
Authors: Tesfaigzi Yohannes , Fischer Mark J. , Daheshia Massoud , Green Francis H. Y. , De Sanctis George T. , Wilder Julie A. 
Published: April 2014

AbstractAllergic airway responses cause proliferation of epithelial cells and mucus cell metaplasia (MCM), and the resolution of MCM involves reduction of cell numbers. The role of inflammation and apoptosis on this process was investigated in P-selectin +/+ and −/− mice sensitized and challenged with OVA by analyzing the expression and the role of regulators of apoptosis in metaplastic mucus cells. No differences were observed in MCM at 5 days of allergen exposure between +/+ and −/− mice, despite reduced IL-13 levels in −/− mice. Although IL-4 levels were similar in both −/− and +/+ mice, IL-13 and IL-5 levels had decreased and IFN-γ levels were increased earlier in −/− compared with +/+ mice. MCM levels were decreased 4-fold at 7 days of allergen exposure in −/− mice and at 15 days in +/+ mice. The percentage of Bax-expressing mucus cells increased significantly at 7 days in −/− mice and at 10 days in +/+ mice. The Bax-positive mucus cells exhibited caspase-specific cleavage of cytokeratin 18. IFN-γ caused Bax expression in IL-13-induced MCM in microdissected airway cultures. MCM remained significantly elevated in Bax −/− mice following 15 days of allergen exposure compared with +/+ mice, while the number of eosinophils was reduced in both Bax +/+ and −/− mice at 15 days. Together, these data demonstrate that reduced IL-13 levels were sufficient to elicit maximum MCM, that IFN-γ induces Bax in metaplastic mucus cells, and that Bax plays a critical role in the resolution of MCM, but not in the resolution of eosinophils.