bluuebunny/crossref_metadata_2025 huggingface dataset:
Δ9-Tetrahydrocannabinol Treatment Suppresses Immunity and Early IFN-γ, IL-12, and IL-12 Receptor β2 Responses toLegionella pneumophilaInfection
Authors: Klein Thomas W. , Newton Catherine A. , Nakachi Noryia , Friedman Herman
Published: April 2014

The marijuana cannabinoid, Δ9-tetrahydrocannabinol (THC), suppresses immunity to Legionella pneumophila and development of Th1 activity and cell-mediated immunity. In the current study, THC effects on cytokines regulating the development of Th1 cells were examined. BALB/c mice showed significant increases in serum IL-12 and IFN-γ within hours of infection; however, the levels of these Th1-promoting cytokines as well as resistance to a challenge infection were suppressed by THC (8 mg/kg) injected 18 h before priming. The Th2-promoting cytokine, IL-4, was increased within hours of a Legionella infection and was further increased by THC treatment. These results suggested that THC injection suppressed the cytokine environment promoting Th1 immunity. In additional experiments, THC pretreatment and infection of IL-4 knockout mice showed that serum IL-12 and IFN-γ were suppressed equally in both knockout and normal mice. This suggested that the drug-induced increase in IL-4 was not responsible for the decreases in serum IL-12 and IFN-γ. However, THC treatment was shown to suppress the expression of IL-12 receptor β2 mRNA, indicating that, in addition to suppression of IL-12, THC injection suppressed the expression of IL-12 receptors. Finally, the role of cannabinoid receptors in Th1-promoting cytokine suppression was examined, and results with receptor antagonists showed that both cannabinoid receptors 1 and 2 were involved. It is suggested that suppression of Th1 immunity to Legionella is not due to an increase in IL-4 production but to a decrease in IFN-γ and IL-12. Furthermore, both types of cannabinoid receptors are involved.
NK Cells Cause Liver Injury and Facilitate the Induction of T Cell-Mediated Immunity to a Viral Liver Infection
Authors: Liu Zhang-Xu , Govindarajan Sugantha , Okamoto Shigefumi , Dennert Gunther
Published: April 2014

NK cells are a relatively rare cell population in peripheral lymphoid organs but are abundant in the liver, raising questions as to their function in immune responses to infections of this organ. To investigate this, cell-mediated immunity to viral liver infection induced by a type 5, replication-defective, adenovirus was examined. It is shown that NK cells in the absence of T cells cause hepatocyte apoptosis in virus-infected livers associated with an increase in liver enzymes in the serum. Concomitantly, NK cells induce production of IFN-γ, inhibitable by their elimination before infection. NK cells are shown to be necessary for optimal priming of virus-specific T cells, assessed by delayed-type hypersensitivity response and CTL activity, consistent with their ability to secrete IFN-γ. The conclusion is drawn that NK cells mediate two important functions in the liver: they induce cell death in the infected organ and concomitantly stimulate the induction of T cell-mediated immunity by release of IFN-γ.
Resveratrol Suppresses TNF-Induced Activation of Nuclear Transcription Factors NF-κB, Activator Protein-1, and Apoptosis: Potential Role of Reactive Oxygen Intermediates and Lipid Peroxidation
Authors: Manna Sunil K. , Mukhopadhyay Asok , Aggarwal Bharat B.
Published: April 2014

Resveratrol (trans-3,4′,5-trihydroxystilbene), a polyphenolic phytoalexin found in grapes, fruits, and root extracts of the weed Polygonum cuspidatum, exhibits anti-inflammatory, cell growth-modulatory, and anticarcinogenic effects. How this chemical produces these effects is not known, but it may work by suppressing NF-κB, a nuclear transcription factor that regulates the expression of various genes involved in inflammation, cytoprotection, and carcinogenesis. In this study, we investigated the effect of resveratrol on NF-κB activation induced by various inflammatory agents. Resveratrol blocked TNF-induced activation of NF-κB in a dose- and time-dependent manner. Resveratrol also suppressed TNF-induced phosphorylation and nuclear translocation of the p65 subunit of NF-κB, and NF-κB-dependent reporter gene transcription. Suppression of TNF-induced NF-κB activation by resveratrol was not restricted to myeloid cells (U-937); it was also observed in lymphoid (Jurkat) and epithelial (HeLa and H4) cells. Resveratrol also blocked NF-κB activation induced by PMA, LPS, H2O2, okadaic acid, and ceramide. The suppression of NF-κB coincided with suppression of AP-1. Resveratrol also inhibited the TNF-induced activation of mitogen-activated protein kinase kinase and c-Jun N-terminal kinase and abrogated TNF-induced cytotoxicity and caspase activation. Both reactive oxygen intermediate generation and lipid peroxidation induced by TNF were suppressed by resveratrol. Resveratrol’s anticarcinogenic, anti-inflammatory, and growth-modulatory effects may thus be partially ascribed to the inhibition of activation of NF-κB and AP-1 and the associated kinases.
A Self MHC Class II β-Chain Peptide Prevents Diabetes in Nonobese Diabetic Mice
Authors: Chaturvedi Pratibha , Agrawal Babita , Zechel Marc , Lee-Chan Edwin , Singh Bhagirath
Published: April 2014

We explored T cell responses to the self class II MHC (I-Ag7) β-chain-derived peptides in diabetic and prediabetic nonobese diabetic (NOD) mice. We found that one of these immunodominant epitopes of the β-chain of I-Ag7 molecule, peptide 54–76, could regulate autoimmunity leading to diabetes in NOD mice. T cells from prediabetic young NOD mice do not respond to the peptide 54–76, but T cells from diabetic NOD mice proliferated in response to this peptide. T cells from older nondiabetic mice or mice protected from diabetes do not respond to this peptide, suggesting a role for peptide 54–76-specific T cells in pathogenesis of diabetes. We show that this peptide is naturally processed and presented by the NOD APCs to self T cells. However, the peptide-specific T cells generated after immunization of young mice regulate autoimmunity in NOD mice by blocking the diabetogenic cells in adoptive transfer experiments. The NOD mice immunized with this peptide are protected from both spontaneous and cyclophosphamide-induced insulin-dependent diabetes mellitus. Immunization of young NOD mice with this peptide elicited T cell proliferation and production of Th2-type cytokines. In addition, immunization with this peptide induced peptide-specific Abs of IgG1 isotype that recognized native I-Ag7 molecule on the cell surface and inhibited the T cell proliferative responses. These results suggest that I-Aβg7(54–76) peptide-reactive T cells are involved in the pathogenesis of diabetes. However, immunization with this peptide at young age induces regulatory cells and the peptide-specific Abs that can modulate autoimmunity in NOD mice and prevent spontaneous and induced diabetes.
Up-Regulation of Macrophage Inflammatory Protein-3α/CCL20 and CC Chemokine Receptor 6 in Psoriasis
Authors: Homey Bernhard , Dieu-Nosjean Marie-Caroline , Wiesenborn Andrea , Massacrier Catherine , Pin Jean-Jacques , Oldham Elizabeth , Catron Daniel , Buchanan Matthew E. , Müller Anja , deWaal Malefyt Rene , Deng Glenn , Orozco Rocio , Ruzicka Thomas , Lehmann Percy , Lebecque Serge , Caux Christophe , Zlotnik Albert
Published: April 2014

Autoimmunity plays a key role in the immunopathogenesis of psoriasis; however, little is known about the recruitment of pathogenic cells to skin lesions. We report here that the CC chemokine, macrophage inflammatory protein-3α, recently renamed CCL20, and its receptor CCR6 are markedly up-regulated in psoriasis. CCL20-expressing keratinocytes colocalize with skin-infiltrating T cells in lesional psoriatic skin. PBMCs derived from psoriatic patients show significantly increased CCR6 mRNA levels. Moreover, skin-homing CLA+ memory T cells express high levels of surface CCR6. Furthermore, the expression of CCR6 mRNA is 100- to 1000-fold higher on sorted CLA+ memory T cells than other chemokine receptors, including CXCR1, CXCR2, CXCR3, CCR2, CCR3, and CCR5. In vitro, CCL20 attracted skin-homing CLA+ T cells of both normal and psoriatic donors; however, psoriatic lymphocytes responded to lower concentrations of chemokine and showed higher chemotactic responses. Using ELISA as well as real-time quantitative PCR, we show that cultured primary keratinocytes, dermal fibroblasts, and dermal microvascular endothelial and dendritic cells are major sources of CCL20, and that the expression of this chemokine can be induced by proinflammatory mediators such as TNF-α/IL-1β, CD40 ligand, IFN-γ, or IL-17. Taken together, these findings strongly suggest that CCL20/CCR6 may play a role in the recruitment of T cells to lesional psoriatic skin.
Histamine Is a Potent Inducer of IL-18 and IFN-γ in Human Peripheral Blood Mononuclear Cells
Authors: Kohka Hideo , Nishibori Masahiro , Iwagaki Hiromi , Nakaya Naoki , Yoshino Tadashi , Kobashi Kenta , Saeki Kiyomi , Tanaka Noriaki , Akagi Tadaatsu
Published: April 2014

Histamine (10−7 to 10−4 M) concentration-dependently stimulated the production of IL-18 and IFN-γ and inhibited the production of IL-2 and IL-10 in human PBMCs. Histamine in the same concentration range did not induce the production of IL-12 at all. The stimulatory or inhibitory effects of histamine on cytokine production were all antagonized by H2 receptor antagonists ranitidine and famotidine in a concentration-dependent manner, but not by H1 and H3 receptor antagonists. Selective H2 receptor agonists, 4-methylhistamine and dimaprit, mimicked the effects of histamine on five kinds of cytokine production. The EC50 values of histamine, 4-methylhistamine, and dimaprit for the production of IL-18 were 1.5, 1.0, and 3.8 μM, respectively. These findings indicated that histamine caused cytokine responses through the stimulation of H2 receptors. All effects of histamine on cytokine responses were also abolished by the presence of either anti-IL-18 Ab or IL-1β-converting enzyme/caspase-1 inhibitor, indicating that the histamine action is dependent on mature IL-18 secretion and that IL-18 production is located upstream of the cytokine cascade activated by histamine. The addition of recombinant human IL-18 to the culture concentration-dependently stimulated IL-12 and IFN-γ production and inhibited the IL-2 and IL-10 production. IFN-γ production induced by IL-18 was inhibited by anti-IL-12 Ab, showing the marked contrast of the effect of histamine. Thus histamine is a very important modulator of Th1 cytokine production in PBMCs and is quite unique in triggering IL-18-initiating cytokine cascade without inducing IL-12 production.
Alterations in the Spinal Cord T Cell Repertoire During Relapsing Experimental Autoimmune Encephalomyelitis
Authors: Fritz Robert B. , Wang Xudong , Zhao Ming-Lang
Published: April 2014

The CNS T cell repertoire was analyzed by RT-PCR, spectratyping, and nucleotide sequencing of the amplified products at different times following adoptive transfer of a CD4+, Th1, VB2+ encephalitogenic SJL/J proteolipid protein peptide 139–151-specific T cell clone. The third complementarity-determining region of TCR B chains in the spinal cord was used as an indicator of T cell heterogeneity. Spectratypic analysis revealed that a single peak corresponding to the third complementarity-determining region of the initiating T cell clone predominated during the acute phase. During recovery and relapse the complexity of the spectratype increased. DNA sequence analysis revealed that the donor clone predominated at the acute phase. By the first relapse the donor clone, although represented most frequently, was a minority of the total. Spectratypic analysis of the same samples for several other VB families revealed their presence during acute disease or relapses but, with the exception of VB17, their absence during the recovery stage.
IL-2 Unresponsiveness in Anergic CD4+ T Cells Is Due to Defective Signaling Through the Common γ-Chain of the IL-2 Receptor
Authors: Grundström Susanna , Dohlsten Mikael , Sundstedt Anette
Published: April 2014

Repeated administration of the superantigen staphylococcal enterotoxin A to mice transduces a state of anergy in the CD4+ T cell compartment, characterized by inhibition of IL-2 production and clonal expansion in vivo. In contrast to what has been reported on anergic T cell clones in vitro, culture of in vivo anergized CD4+ T cells in the presence of exogenous IL-2 did not overcome the block in responsiveness. In this study, we demonstrate that CD4+ T cells from mice anergized with staphylococcal enterotoxin A also exhibit a reduced proliferative capacity in response to IL-7 and IL-15, cytokines that share a common γ-chain with the IL-2R. Flow-cytometric analysis revealed only modest changes in the expression of the different IL-2R chains. In a number of experiments, our results also provide evidence that excludes a major role of the IL-2R α-chain in this system. According to these results, the inability of anergic cells to respond to IL-2 is not mainly due to a down-regulation of the high affinity IL-2R, but to a perturbation in intracellular signaling. Our study confirmed that the activation and tyrosine phosphorylation of Janus-associated kinase 3 and STAT5 were considerably weaker after anergy induction. Moreover, anergic CD4+ T cells showed significantly reduced DNA-binding ability to STAT5-specific elements. Taken together, we suggest that the observed IL-2 unresponsiveness in anergic CD4+ T cells could be due to a defect in signaling through the common γ-chain of the IL-2R.
Blocking the Common γ-Chain of Cytokine Receptors Induces T Cell Apoptosis and Long-Term Islet Allograft Survival
Authors: Li Xian Chang , Ima Azine , Li Yongsheng , Zheng Xin Xiao , Malek Thomas R. , Strom Terry B.
Published: April 2014

The common γc-chain is an essential signaling component shared by all known T cell growth factor (TCGF) receptors (i.e., IL-2, IL-4, IL-7, IL-9, and IL-15). In the present study, we have studied the effect of γc-chain blockade on T cell activation and allograft rejection. Treatment of B6AF1 (H-2b/d.k) recipient mice with anti-γc mAbs induced long-term survival of DBA/2 (H-2d) islet allografts (>150 days, n = 8), whereas control Ab-treated mice rejected the islet allografts within 17 days (n = 6). The state of engraftment induced by the anti-γc mAbs was remarkably stable, as recipient mice bearing the primary islet allografts accepted a second DBA/2 islet allograft without further immunosuppression and systemic administration of high doses of IL-2Ig fusion protein failed to provoke rejection. Blocking the γc-chain inhibited T cell proliferation and induced T cell apoptosis by repressing expression of Bcl-2. Our data suggest that one means of inducing T cell apoptosis and stable allograft survival can be achieved via γc-chain blockade.
Protein Tyrosine Phosphatase Activity Is Required for IL-4 Induction of IL-4 Receptor α-Chain
Authors: Huang Hua , Paul William E.
Published: April 2014

To investigate the role of protein tyrosine phosphatases in IL-4Rα-chain expression and signaling, we first established that SHP-1, but not SHP-2, coimmunoprecipitated with anti-IL-4Rα chain Abs in extracts prepared from resting lymphocytes. We further observed that the protein tyrosine phosphatase inhibitors Na3VO4 and pervanadate blocked the striking induction of IL-4Rα-chain expression that is mediated by IL-4. However, Na3VO4 did not diminish IL-4-induced Stat6 phosphorylation nor did it block the IL-4-mediated increase in IL-4Rα-chain mRNA. The striking inhibition in total cellular IL-4Rα-chain and in cell surface IL-4 receptors was associated with an inhibition of biosynthetic labeling of IL-4Rα-chain after a 30- min pulse with [35S] methionine, indicating that reduction of IL-4Rα-chain protein resulted from either a diminished production of the receptor or a rapid degradation, possibly as a result of phosphorylation of the receptor in an early biosynthetic cellular compartment. Control of newly synthesized IL-4Rα-chain protein expression by phosphatase may provide a novel means to regulate IL-4 responsiveness.
Non-CD28 Costimulatory Molecules Present in T Cell Rafts Induce T Cell Costimulation by Enhancing the Association of TCR with Rafts
Authors: Yashiro-Ohtani Yumi , Zhou Xu-Yu , Toyo-oka Kazuhito , Tai Xu-Guang , Park Cheung-Seog , Hamaoka Toshiyuki , Abe Ryo , Miyake Kensuke , Fujiwara Hiromi
Published: April 2014

While CD28 functions as the major T cell costimulatory receptor, a number of other T cell molecules have also been described to induce T cell costimulation. Here, we investigated the mechanisms by which costimulatory molecules other than CD28 contribute to T cell activation. Non-CD28 costimulatory molecules such as CD5, CD9, CD2, and CD44 were present in the detergent-insoluble glycolipid-enriched (DIG) fraction/raft of the T cell surface, which is rich in TCR signaling molecules and generates a TCR signal upon recruitment of the TCR complex. Compared with CD3 ligation, coligation of CD3 and CD5 as an example of DIG-resident costimulatory molecules led to an enhanced association of CD3 and DIG. Such a DIG redistribution markedly up-regulated TCR signaling as observed by ZAP-70/LAT activation and Ca2+ influx. Disruption of DIG structure using an agent capable of altering cholesterol organization potently diminished Ca2+ mobilization induced by the coligation of CD3 and CD5. This was associated with the inhibition of the redistribution of DIG although the association of CD3 and CD5 was not affected. Thus, the DIG-resident costimulatory molecules exert their costimulatory effects by contributing to an enhanced association of TCR/CD3 and DIG.
Phosphatidylinositol 3-Kinase as a Mediator of TNF-Induced NF-κB Activation
Authors: Reddy Shrikanth A. G. , Huang Jianyi H. , Liao Warren S.-L.
Published: April 2014

The activation of transcription factor NF-κB by TNF involves the stimulation of a novel signaling cascade. In this paper we show that phosphatidylinositol 3-kinase (PI 3-kinase) may play a pivotal role in TNF-mediated activation of NF-κB-dependent genes. Consistent with its involvement in TNF signaling, PI 3-kinase activities in HepG2 and U937 cells can be stimulated by TNF in a rapid but transient manner through a mechanism that may involve its association with the insulin receptor substrate-1. A dominant-negative mutant of the p85 regulatory subunit of PI 3-kinase, which is a potent inhibitor of PI 3-kinase signaling, effectively blocked the TNF-induced expression of an NF-κB-dependent reporter gene. Although PI 3-kinase may be required for NF-κB activation, overexpression of its p110 catalytic subunit alone was unable to induce an NF-κB/chloramphenicol acetyltransferase (CAT) reporter gene. However, when TNF was added to p110-overexpressing cells, there was a synergistic activation of the NF-κB/CAT reporter, suggesting that other TNF-inducible signals may cooperate with PI 3-kinase to activate NF-κB. Consistent with its role in NF-κB activation, inhibition of PI 3-kinase activity by wortmannin or LY294002 greatly potentiated TNF-induced apoptosis. This TNF/wortmannin-induced apoptosis was markedly prevented in cells overexpressing Rel A. Taken together, our results indicate that a PI 3-kinase-regulated step in TNF-signaling is critical for the expression of NF-κB-dependent genes.
Identification of a Functional NF-κB Site in the Platelet Endothelial Cell Adhesion Molecule-1 Promoter
Authors: Botella Luisa M. , Puig-Kröger Amaya , Almendro Nuria , Sánchez-Elsner Tilman , Muñoz Eduardo , Corbí Angel , Bernabéu Carmelo
Published: April 2014

Platelet endothelial cell adhesion molecule-1 (PECAM-1) is a type I transmembrane adhesion protein of 130 kDa that belongs to a subgroup of the Ig gene superfamily, characterized by the presence of immunoreceptor tyrosine-based inhibitory motifs. PECAM-1 is expressed in circulating platelets, monocytes, neutrophils, a selective subgroup of T cells, and in endothelial cells, where it is preferentially located at intercellular junctions and participates in leukocyte transmigratory processes. The identification of two consensus NF-κB sites within the PECAM-1 promoter led us to analyze their possible involvement in the PECAM-1 expression regulated by inflammatory stimuli. We found that surface expression and promoter activity of PECAM-1 in myeloid cells are regulated by modulators of NF-κB, including TNF-α, PMA, and pyrrolidine dithiocarbamate. Mobility shifts assays identified a specific NF-κB-binding element at +110/+120, whose mutation abolished the basal promoter activity of PECAM-1 and decreased NF-κB-dependent responses of the PECAM-1 gene promoter. Furthermore, cotransfection experiments with an expression vector encoding the p65 subunit of NF-κB showed transactivation of the PECAM-1 promoter. These results demonstrate that NF-κB can regulate the transcriptional activity of PECAM-1.
Differences Among HIV-1 Variants in Their Ability to Elicit Secretion of TNF-α
Authors: Khanna Kristen V. , Yu Xiao-Fang , Ford David H. , Ratner Lee , Hildreth James K. , Markham Richard B.
Published: April 2014

HIV-1 infection of human PBMC has been shown to elicit secretion of several different cytokines. TNF-α secretion induced by this virus has been of particular interest because it has been associated with the development of HIV-1 dementia and because TNF-α increases viral replication by enhancing NF-κB interaction with the viral promoter, the HIV-1 long terminal repeat. Thus, an autocrine pathway is potentially created in which HIV-1 stimulates its own replication. Conflicting reports exist, however, on the ability of HIV-1 to induce TNF-α secretion in vitro or in vivo. Using experimental protocols that controlled for potential bacterial endotoxin-induced TNF-α secretion, the current study demonstrates significant differences in TNF-α-eliciting properties among primary and laboratory obtained HIV-1. The relative TNF-α-inducing ability of different variants is conserved when tested using PBMC from different individuals. Elicitation of TNF-α secretion was not blocked by exposure of cells to zidovudine, indicating that viral integration was not required to induce secretion. Rather, the interaction between the virus and cell surface is critical for TNF-α induction, as Abs against CD4 or CCR5 blocked the induction of TNF-α synthesis by PBMC when added before virus exposure. Furthermore, the ability to induce TNF-α secretion mapped to a region of the HIV-1 env gene that includes the third hypervariable domain. Differences in the ability of different HIV-1 variants to elicit TNF-α may account for individual differences in HIV-1 disease course.
A Bactericidal Monoclonal Antibody Elicits a Change in Its Antigen, OspB of Borrelia burgdorferi, That Can Be Detected by Limited Proteolysis
Authors: Katona Laura I. , Ayalew Sahlu , Coleman James L. , Benach Jorge L.
Published: April 2014

mAb CB2, directed against outer surface protein B (OspB), causes bacteriolysis of Borrelia burgdorferi in the absence of complement. How this happens is unknown. We examined the effect of mAb binding on OspB tertiary structure by using limited proteolysis to probe changes in protein conformation. Truncated OspB (tOspB) that lacked N-terminal lipid was cleaved by four enzymes: trypsin, endoproteinase Arg-C, endoproteinase Asp-N, and endoproteinase Glu-C. CB2 affected the cleavage by trypsin and Arg-C, but not by AspN or Glu-C. None of the enzymes cleaved CB2 under these conditions. Both trypsin and Arg-C cleaved tOspB near the N-terminus; CB2 slowed the rate of cleavage, but did not affect the identity of the sites cleaved. Irrelevant mAb had no effect, indicating that the effect was specific. CB2 was active against tOspB of strain B31, but not against tOspB of strain BEP4, to which it does not bind, suggesting that binding was required to elicit the effect on cleavage. With trypsin, CB2 showed a maximal effect at 8 mol of tOspB to 1 mol of mAb. At this ratio, not enough CB2 was present to bind all the tOspB; therefore, either CB2 shows turnover or CB2 acts by binding tOspB and effecting a change in this tOspB such that it, in turn, propagates the effect in other molecules of tOspB. Regardless of the mechanism, these data show that CB2 elicits a change in tOspB that can be measured by its reduced susceptibility to protease cleavage.
Highly Altered Vβ Repertoire of T Cells Infiltrating Long-Term Rejected Kidney Allografts
Authors: Gagne Katia , Brouard Sophie , Giral Magali , Sebille Fabien , Moreau Anne , Guillet Marina , Bignon Jean-Denis , Imbert Berthe-Marie , Cuturi Maria-Cristina , Soulillou Jean-Paul
Published: April 2014

Chronic rejection represents a major cause of long-term kidney graft loss. T cells that are predominant in long-term rejected kidney allografts (35 ± 10% of area infiltrate) may thus be instrumental in this phenomenom, which is likely to be dependant on the indirect pathway of allorecognition only. We have analyzed the variations in T cell repertoire usage of the Vβ chain at the complementary determining region 3 (CDR3) level in 18 human kidney grafts lost due to chronic rejection. We observed a strongly biased intragraft TCR Vβ usage for the majority of Vβ families and also a very high percentage (55%) of Vβ families exhibiting common and oligoclonal Vβ-Cβ rearrangements in the grafts of patients with chronic rejection associated with superimposed histologically acute lesions. Furthermore, Vβ8 and Vβ23 families exhibited common and oligoclonal Vβ-Jβ rearrangements in 4 of 18 patients (22%). Several CDR3 amino acid sequences were found for the common and oligoclonal Vβ8-Jβ1.4 rearrangement. Quantitative PCR showed that biased Vβ transcripts were also overexpressed in chronically rejected kidneys with superimposed acute lesions. In contrast, T lymphocytes infiltrating rejected allografts with chronic rejection only showed an unaltered Gaussian-type CDR3 length distribution. This pattern suggests that late graft failure associated with histological lesions restricted to Banff-defined chronic rejection does not involve T cell-mediated injury. Thus, our observation suggests that a limited number of determinants stimulates the recipient immune system in long-term allograft failure. The possibility of a local response against viral or parenchymatous cell-derived determinants is discussed.
Retrovirally Mediated IFN-β Transduction of Macrophages Induces Resistance to HIV, Correlated with Up-Regulation of RANTES Production and Down-Regulation of C-C Chemokine Receptor-5 Expression
Authors: Cremer Isabelle , Vieillard Vincent , De Maeyer Edward
Published: April 2014

Constitutive expression of IFN-β by HIV target cells may be an alternative or complementary therapeutic approach for the treatment of AIDS. We show that macrophages derived from CD34+ cells from umbilical cord blood can be efficiently transduced by a retroviral vector carrying the IFN-β coding sequence. This results in resistance to infection by a macrophage-tropic HIV type 1, as shown by the drastic reduction in the HIV DNA copy number per cell and in p24 release. Moreover, IFN-β transduction totally blocked secretion of proinflammatory cytokines after HIV infection. The constitutive IFN-β production also resulted in an increased production of IL-12 and IFN-γ Th1-type cytokines and of the β-chemokines macrophage-inflammatory protein-1α, macrophage-inflammatory protein-1β, and RANTES. RANTES was found to be involved in the HIV resistance observed, and this was correlated with a down-regulation of the CCR-5 HIV entry coreceptor. These results demonstrate the feasibility and the efficacy of such IFN-β-mediated gene therapy. In addition to inhibiting HIV replication, IFN-β transduction could have beneficial immune effects in HIV-infected patients by favoring cellular immune responses.
IL-10 Contributes to the Inhibition of Contact Hypersensitivity in Mice Treated with Photodynamic Therapy
Authors: Simkin Guillermo O. , Tao Jing-Song , Levy Julia G. , Hunt David W. C.
Published: April 2014

We have explored the effect of photodynamic therapy (PDT) with verteporfin on the induction and expression of contact hypersensitivity (CHS) to 2,4-dinitrofluorobenzene (DNFB) in normal mice and IL-10-deficient mice. Our results indicate that DNFB sensitized mice given PDT with verteporfin and whole body red light irradiation exhibited a significant reduction in CHS compared with control animals. Administration of rIL-12 reversed the effect(s) of PDT as did treatment of mice with anti-IL-10-neutralizing Ab. Knockout mice deficient in IL-10 were found to be resistant to the inhibitory effects of PDT. In vitro proliferative responses using spleen cells from DNFB-sensitized and PDT-treated mice showed a significantly lower response to DNBS as compared with cells from DNFB-sensitized mice or DNFB and PDT-treated IL-10-deficient mice. Finally, naive mice exposed to PDT exhibited an increase in skin IL-10 levels, which peaked between 72 and 120 h post-PDT. Together these data support the role of IL-10 as a key modulator in the inhibition of the CHS response by whole body PDT.
Purification and Characterization of Two Mannan-Binding Lectins from Mouse Serum
Authors: Hansen Søren , Thiel Steffen , Willis Anthony , Holmskov Uffe , Jensenius Jens Christian
Published: April 2014

Mannan-binding lectin (MBL) is a serum protein that activates the complement system after binding to glycoconjugates found on the surface of microorganisms. By molecular cloning two forms of MBL have been identified in the mouse (mMBL-A and mMBL-C), but only mMBL-A has been purified and characterized at the protein level. MBL-C has been termed the liver form of MBL. The present report describes the purification and characterization of mMBL-A and mMBL-C from serum. The two forms of mMBL could be separated both by ion-exchange and carbohydrate-affinity chromatography. The initial identification by immunochemical technique was confirmed by N-terminal amino-acid sequencing. Both proteins give bands corresponding to polypeptide chains of 28 kDa on SDS-PAGE in the reduced state, but mMBL-A migrated more rapidly than mMBL-C in acid/urea-PAGE, in accordance with the calculated pIs. Both forms mediated activation of complement component C4 in mannan-coated microtiter wells. MBL-A showed a higher affinity for d-glucose and α-methyl-d-glucose then did MBL-C. Serum concentrations of mMBL-A in laboratory strains and wild mice were found to vary from 5 to 80 μg/ml, with wild mice tending to show higher levels than laboratory strains.
Role for IgE in Airway Secretions: IgE Immune Complexes Are More Potent Inducers Than Antigen Alone of Airway Inflammation in a Murine Model
Authors: Zuberi Riaz I. , Apgar John R. , Chen Swey-Shen , Liu Fu-Tong
Published: April 2014

IgE is present in airway secretions from human patients with allergic rhinitis and bronchial asthma. However, the contribution of IgE present locally to the overall airway inflammation is not well understood. We hypothesize that Ag-specific IgE can capture airborne Ags and form immune complexes. These immune complexes may function as potent inducers of immune responses in the lung, contributing to the perpetuation of airway inflammation. BALB/c mice were first sensitized with OVA in alum systemically and then challenged with nebulized OVA. Bronchoalveolar lavage (BAL) fluid from these mice contained significant amounts of IgE, of which >50% was Ag specific. The IgE levels in airway secretions remained elevated for more than 15 days after the termination of Ag exposure. Significant amounts of IgE-OVA immune complexes were detected in BAL fluid from the OVA-challenged mice. For comparison of IgE immune complexes vs Ag alone, we treated OVA-immunized mice with intranasal administration of trinitrophenyl-OVA or trinitrophenyl-OVA-anti-DNP IgE. Those treated with the immune complexes showed significantly higher levels of IL-4 and more pronounced eosinophilia in BAL fluid than did those receiving the Ag alone. The IgE immune complexes did not augment the inflammatory response in high affinity IgE receptor (FcεRI)-deficient mice. We conclude that IgE present in the airways can capture the Ag and that the immune complexes thus formed may augment allergic airway response in an FcεRI-dependent manner. Thus, IgE present in airway secretions may facilitate Ag-mediated allergic airway inflammation.
IFN-γ Shapes Immune Invasion of the Central Nervous System Via Regulation of Chemokines
Authors: Tran Elise H. , Prince Esther N. , Owens Trevor
Published: April 2014

Dynamic interplay between cytokines and chemokines directs trafficking of leukocyte subpopulations to tissues in autoimmune inflammation. We have examined the role of IFN-γ in directing chemokine production and leukocyte infiltration to the CNS in experimental autoimmune encephalomyelitis (EAE). BALB/c and C57BL/6 mice are resistant to induction of EAE by immunization with myelin basic protein. However, IFN-γ-deficient (BALB/c) and IFN-γR-deficient (C57BL/6) mice developed rapidly progressing lethal disease. Widespread demyelination and disseminated leukocytic infiltration of spinal cord were seen, unlike the focal perivascular infiltrates in SJL/J mice. Gr-1+ neutrophils predominated in CNS, and CD4+ T cells with an activated (CD69+, CD25+) phenotype and eosinophils were also present. RANTES and macrophage chemoattractant protein-1, normally up-regulated in EAE, were undetectable in IFN-γ- and IFN-γR-deficient mice. Macrophage inflammatory protein-2 and T cell activation gene-3, both neutrophil-attracting chemokines, were strongly up-regulated. There was no induction of the Th2 cytokines, IL-4, IL-10, or IL-13. RNase protection assays and RT-PCR showed the prevalence of IL-2, IL-3, and IL-15, but no increase in IL-12p40 mRNA levels in IFN-γ- or IFN-γR-deficient mice with EAE. Lymph node cells from IFN-γ-deficient mice proliferated in response to myelin basic protein, whereas BALB/c lymph node cells did not. These findings show a regulatory role for IFN-γ in EAE, acting on T cell proliferation and directing chemokine production, with profound implications for the onset and progression of disease.
The Human UTY Gene Encodes a Novel HLA-B8-Restricted H-Y Antigen
Authors: Warren Edus H. , Gavin Marc A. , Simpson Elizabeth , Chandler Phillip , Page David C. , Disteche Christine , Stankey Kimberly A. , Greenberg Philip D. , Riddell Stanley R.
Published: April 2014

The mammalian Y chromosome encodes male-specific minor histocompatibility (H-Y) Ags that are recognized by female T cells in an MHC-restricted manner. Two human H-Y epitopes presented by HLA-A2 and HLA-B7, respectively, have been identified previously and both are derived from the SMCY gene. We previously isolated CD8+ CTL clones that recognized a male-specific minor histocompatibility Ag presented by HLA-B8. In contrast to the SMCY-encoded H-Y epitopes, the B8/H-Y Ag was not presented by fibroblasts from male donors, suggesting that it was encoded by a novel gene. We now report that the HLA-B8-restricted H-Y epitope is defined by the octameric peptide LPHNHTDL corresponding to aa residues 566–573 of the human UTY protein. Transcription of the UTY gene is detected in a wide range of human tissues, but presentation of the UTY-derived H-Y epitope to CTL by cultured human cells shows significant cell-type specificity. Identification of this CTL-defined H-Y epitope should facilitate analysis of its contribution to graft/host interactions following sex-mismatched organ and bone marrow transplantation.
High Levels of IL-17 in Rheumatoid Arthritis Patients: IL-15 Triggers In Vitro IL-17 Production Via Cyclosporin A-Sensitive Mechanism
Authors: Ziolkowska Maria , Koc Anna , Luszczykiewicz Grazyna , Ksiezopolska-Pietrzak Krystyna , Klimczak Ewa , Chwalinska-Sadowska Hanna , Maslinski Wlodzimierz
Published: April 2014

Recent data suggest that IL-15 plays an important role in the pathogenesis of rheumatoid arthritis. In the present study, we hypothesized that elevated in the joints of rheumatoid arthritis, but not osteoarthritis, patients, IL-15 may exert its proinflammatory properties via the induction of IL-17, a cytokine known to stimulate synoviocytes to release several mediators of inflammation including IL-6, IL-8, GM-CSF and PGE2. To test this hypothesis, we first measured the levels of IL-17 and IL-15 using specific ELISA and found that synovial fluids of patients with rheumatoid arthritis, but not with osteoarthritis, contain high levels of these cytokines. A strong correlation between IL-15 and IL-17 levels in synovial fluids was observed. Among tested factors, LPS and TNF-α failed, IL-15 and IL-2 were equipotent, and PMA + ionomycin was far more efficient in the induction of IL-17 secretion by PBMCs isolated from healthy blood donors. Interestingly, synovial fluid cells, in contrast to PBMCs isolated from patients with rheumatoid arthritis, but not osteoarthritis, respond to PMA + ionomycin with much lower, comparable to IL-15-triggered IL-17 secretion. Moreover, PMA + ionomycin-triggered IL-17 secretion is completely or partially blocked in the presence of low doses of cyclosporin A or high doses of methylprednisolone, respectively. IL-15-triggered IL-17 secretion by PBMCs was completely inhibited by these drugs. Thus, our results suggest for the first time that IL-15 may represent a physiological trigger that via cyclosporin A and steroid sensitive pathways leads to the overproduction of IL-17 in the joints of rheumatoid arthritis patients.
Integrated Signals Between IL-13, IL-4, and IL-5 Regulate Airways Hyperreactivity
Authors: Webb Dianne C. , McKenzie Andrew N. J. , Koskinen Aulikki M. L. , Yang Ming , Mattes Joërg , Foster Paul S.
Published: April 2014

In this investigation, we have examined the integrated relationship between IL-13, IL-4, and IL-5 for the development of airways hyperreactivity (AHR) in a model of asthma in BALB/c mice. Sensitization and aeroallergen challenge of both wild-type (WT) and IL-13 gene-targeted (IL-13−/−) mice induced allergic disease that was characterized by pulmonary eosinophilia and AHR to β-methacholine. Although these responses in IL-13−/− mice were heightened compared with WT, they could be reduced to the level in nonallergic mice by the concomitant neutralization of IL-4. Mice in which both IL-4 and IL-13 were depleted displayed a marked reduction in tissue eosinophils, despite the development of a blood eosinophilia. Similar neutralization of IL-4 in WT mice only partially reduced AHR with no effect on tissue eosinophilia. In addition, neutralization of IL-5 in IL-13−/− mice, but not in WT mice, inhibited AHR, suggesting that tissue eosinophilia is linked to the mechanism underlying AHR only in the absence of IL-13. Additionally, mucus hypersecretion was attenuated in IL-13−/− mice, despite the persistence of AHR. Taken together, our data suggest both a modulatory role for IL-13 during sensitization and a proinflammatory role during aeroallergen challenge. The latter process appears redundant with respect to IL-4.
Vasoactive Intestinal Peptide and Pituitary Adenylate Cyclase-Activating Polypeptide Inhibit T Cell-Mediated Cytotoxicity by Inhibiting Fas Ligand Expression
Authors: Delgado Mario , Ganea Doina
Published: April 2014

We reported recently that the neuropeptides vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) protect CD4+ T cells against Ag-induced apoptosis by down-regulating the expression of Fas ligand (FasL). Because the cytotoxic activity of CD8+ CTLs is mediated through two mechanisms, which involve the perforin/granzyme and the FasL/Fas pathways, in this study we investigated the effects of VIP/PACAP on the generation and activity of allogeneic CTLs, of CD8+ T1 and T2 effector cells and of alloreactive peritoneal exudate cytotoxic T cells (PEL) generated in vivo. VIP/PACAP did not affect perforin/granzyme-mediated cytotoxicity, perforin gene expression, or granzyme B enzymatic activity, but drastically inhibited FasL/Fas-mediated cytotoxicity against allogeneic or syngeneic Fas-bearing targets. VIP/PACAP inhibit CTL generation, but not the activity of competent CTLs. The inhibition is associated with a profound down-regulation of FasL expression, and these effects are mediated through both VPAC1 and VPAC2 receptors. VIP/PACAP inhibit the FasL/Fas-mediated cytotoxicity of T1 effectors and do not affect T2 cytotoxicity, which is entirely perforin/granzyme mediated. Similar effects were observed in vivo. Both the FasL/Fas-mediated cytotoxicity and FasL expression of cytotoxic allogeneic PELs generated in vivo in the presence of VIP or PACAP were significantly reduced. We conclude that, similar to their effect on CD4+ T cells, the two structurally related neuropeptides inhibit FasL expression in CD8+ cytotoxic T cells and the subsequent lysis of Fas-bearing target cells.
Thapsigargin-Induced Degranulation of Mast Cells Is Dependent on Transient Activation of Phosphatidylinositol-3 Kinase
Authors: Huber Michael , Hughes Michael R. , Krystal Gerald
Published: April 2014

Thapsigargin, which elevates cytosolic calcium levels by inhibiting the sarcoplasmic/endoplasmic reticulum calcium-dependent ATPase, was tested for its ability to degranulate bone marrow-derived mast cells (BMMCs) from src homology 2-containing inositol phosphatase +/+ (SHIP+/+) and SHIP−/− mice. As was found previously with steel factor, thapsigargin stimulated far more degranulation in SHIP−/− than in SHIP+/+ BMMCs, and this was blocked with the phosphatidylinositol-3 (PI-3) kinase inhibitors, LY294002 and wortmannin. In contrast to steel factor, however, this heightened degranulation of SHIP−/− BMMCs was not due to a greater calcium influx into these cells, nor was the thapsigargin-induced calcium influx inhibited by LY294002, suggesting that the heightened thapsigargin-induced degranulation of SHIP−/− BMMCs was due to a PI-3 kinase-regulated step distinct from that regulating calcium entry. An investigation of thapsigargin-stimulated pathways in both cell types revealed that MAPK was heavily but equally phosphorylated. Interestingly, the protein kinase C inhibitor, bisindolylmaleimide (compound 3), totally blocked thapsigargin-induced degranulation in both SHIP+/+ and SHIP−/− BMMCs. As well, thapsigargin stimulated a PI-3 kinase-dependent, transient activation of protein kinase B, and this activation was far greater in SHIP−/− than in SHIP+/+ BMMCs. Consistent with this, thapsigargin was found to be a potent survival factor, following cytokine withdrawal, for both cell types and was more potent with SHIP−/− cells. These studies have both identified an additional PI-3 kinase-dependent step within the mast cell degranulation process, possibly involving 3-phosphoinositide-dependent protein kinase-1 and a diacylglycerol-independent protein kinase C isoform, and shown that the tumor-promoting activity of thapsigargin may be due to its activation of protein kinase B and subsequent promotion of cell survival.
Duplicated DQ Haplotypes Increase the Complexity of Restriction Element Usage in Cattle
Authors: Glass Elizabeth J. , Oliver Robert A. , Russell George C.
Published: April 2014

The MHC of cattle encodes two distinct isotypes of class II molecules, DR and DQ. Unlike humans, cattle lack the DP locus and about half the common haplotypes express duplicated DQ genes. The number and frequency of DQA and DQB alleles means that most cattle are heterozygous. If inter- and/or intrahaplotype pairing of DQA and DQB molecules occurs, cattle carrying DQ-duplicated haplotypes may express more restriction elements than would be predicted by the number of expressed alleles. We are investigating whether duplicated haplotypes cause differences in immune response, particularly in terms of generating protective immunity. We have analyzed the Ag-presenting function of DQ molecules in two heterozygous animals, one of which carries a duplicated haplotype. We compared the class II isotype specificity of T cell clones recognizing a putative vaccinal peptide from foot-and-mouth disease virus (FMDV15). We show for the first time that bovine T cells can recognize Ag in the context of DQ molecules. We also present evidence that interhaplotype pairings of DQA and DQB molecules form functional restriction elements. Both animals showed distinct biases to usage of particular restriction elements. Mainly DQ-restricted clones were derived from the animal with duplicated DQ genes, whereas the majority of clones from the animal with a single DQ gene pair were DR restricted. Furthermore, haplotype bias was observed with both animals. These experiments show that understanding of class II chain pairing in addition to knowledge of the genotype may be important in vaccine design where effective epitope selection is essential.
Cutting Edge: Hierarchy of Chemokine Receptor and TCR Signals Regulating T Cell Migration and Proliferation
Authors: Bromley Shannon K. , Peterson Daniel A. , Gunn Michael D. , Dustin Michael L.
Published: April 2014

Chemokines play an important role in establishing the distribution of lymphocyte subpopulations in primary and secondary lymphoid tissues and in the recruitment of leukocytes to sites of inflammation. However, the potential of chemokines to down-regulate immune responses has not been demonstrated. We now show that certain chemokine gradients have the potential to suppress T cell activation by preventing formation of the immunological synapse, the specialized cell-cell junction that forms before a T cell can be fully activated. Our data reveals an immunosuppressive potential of chemokines engaging the CXCR3 and CCR7 receptors, but not the CXCR4, CCR2, CCR4, or CCR5 receptors. These results suggest a novel mechanism for T cell ignorance of agonist MHC-peptide complexes based on dominant chemokine gradients.
IL-4 and IFN-γ Up-Regulate Substance P Receptor Expression in Murine Peritoneal Macrophages
Authors: Marriott Ian , Bost Kenneth L.
Published: April 2014

While the ability of macrophages to express authentic substance P receptors (i.e., NK-1 receptors) has been inferred from radioreceptor binding assays and functional assays and, most recently, by identification of NK-1 receptor mRNA expression, we know little about NK-1 expression at the protein level or what host factors might up-regulate expression of this receptor. In the present study we demonstrate that the cytokines IL-4 and IFN-γ can increase the expression of NK-1 receptors on murine peritoneal macrophages. Specifically, we show that IL-4 and IFN-γ can elicit increases in the level of mRNA encoding the NK-1 receptor by up to 12- and 13-fold, respectively. Furthermore, these cytokines can significantly increase the expression of the NK-1 receptor protein as measured by Western blot and FACS analysis using specific Abs developed in our laboratory. In addition, we have demonstrated the ability of both IL-4 and IFN-γ to enhance the ability of macrophages to bind substance P as measured by radiolabeled binding assay. The observation that the level of expression of this receptor protein can be enhanced by cytokines that promote either cell-mediated (Th1) or humoral (Th2) immune responses supports the idea that this receptor can be induced during either type of immune response. As such, these results may point to a more ubiquitous role for substance P in the generation of optimal immune responses than previously appreciated.