bluuebunny/crossref_metadata_2025 huggingface dataset:
Augmentation of Effector CD8+ T Cell Generation with Enhanced Granzyme B Expression by IL-27
Authors: Morishima Noriko , Owaki Toshiyuki , Asakawa Masayuki , Kamiya Sadahiro , Mizuguchi Junichiro , Yoshimoto Takayuki
Published: April 2014

IL-27 is a novel IL-12 family member that plays a role in the early regulation of Th1 initiation. We have recently demonstrated that IL-27 has a potent antitumor activity, which is mainly mediated through CD8+ T cells, and also has an adjuvant activity to induce epitope-specific CTL in vivo. In this study, we further investigated the in vitro effect of IL-27 on CD8+ T cells of mouse spleen cells. In a manner similar to CD4+ T cells, IL-27 activated STAT1, -2, -3, -4, and -5, and augmented the expression of T-bet, IL-12Rβ2, and granzyme B, and slightly that of perforin in naive CD8+ T cells stimulated with anti-CD3. IL-27 induced synergistic IFN-γ production with IL-12 and proliferation of naive CD8+ T cells. Moreover, IL-27 enhanced proliferation of CD4+ T cell-depleted spleen cells stimulated by allogeneic spleen cells and augmented the generation of CTL. In STAT1-deficient naive CD8+ T cells, IL-27-induced proliferation was not reduced, but synergistic IFN-γ production with IL-12 was diminished with decreased expression of T-bet, IL-12Rβ2, granzyme B, and perforin. In T-bet-deficient naive CD8+ T cells, IL-27-induced proliferation was hardly reduced, but synergistic IFN-γ production with IL-12 was diminished with decreased expression of IL-12Rβ2, granzyme B, and perforin. However, IL-27 still augmented the generation of CTL from T-bet-deficient CD4+ T cell-depleted spleen cells stimulated by allogeneic spleen cells with increased granzyme B expression. These results suggest that IL-27 directly acts on naive CD8+ T cells in T-bet-dependent and -independent manners and augments generation of CTL with enhanced granzyme B expression.
Runx3 Regulates Integrin αE/CD103 and CD4 Expression during Development of CD4−/CD8+ T Cells
Authors: Grueter Baerbel , Petter Michaela , Egawa Takeshi , Laule-Kilian Kirsten , Aldrian Christine J. , Wuerch Andreas , Ludwig Yvonne , Fukuyama Hidehiro , Wardemann Hedda , Waldschuetz Ralph , Möröy Tarik , Taniuchi Ichiro , Steimle Viktor , Littman Dan R. , Ehlers Marc
Published: April 2014

During thymic T cell development, immature CD4+CD8+ double-positive (DP) thymocytes develop either into CD4+CD8− Th cells or CD4−CD8+ CTLs. Differentially expressed primary factors inducing the fate of these cell types are still poorly described. The transcription factor Runx3/AML-2 Runx, rust dominant factor; AML, acute myeloid leukemia is expressed specifically during the development of CD8 single-positive (SP) thymocytes, where it silences CD4 expression. Deletion of murine Runx3 results in a reduction of CD8 SP T cells and concomitant accumulation of CD4+CD8+ T cells, which cannot down-regulate CD4 expression in the thymus and periphery. In this study we have investigated the role of Runx3 during thymocyte development and CD4 silencing and have identified integrin αE/CD103 on CD8 SP T cells as a new potential target gene of Runx3. We demonstrate that Runx3 is necessary not only to repress CD4, but also to induce CD103 expression during development of CD8 SP T cells. In addition, transgenic overexpression of Runx3 reduced CD4 expression during development of DP thymocytes, leading to a reduced number of CD4 SP thymocytes and an increased number of CD8 SP thymocytes. This reversal is not caused by redirection of specific MHC class II-restricted cells to the CD8 lineage. Overexpression of Runx3 also up-regulated CD103 expression on a subpopulation of CD4 SP T cells with characteristics of regulatory T cells. Thus, Runx3 is a main regulator of CD4 silencing and CD103 induction and thus contributes to the phenotype of CD8 SP T cells during thymocyte development.
The Human β-Defensins (-1, -2, -3, -4) and Cathelicidin LL-37 Induce IL-18 Secretion through p38 and ERK MAPK Activation in Primary Human Keratinocytes
Authors: Niyonsaba François , Ushio Hiroko , Nagaoka Isao , Okumura Ko , Ogawa Hideoki
Published: April 2014

In addition to its physical barrier against invading microorganisms, the skin produces antimicrobial peptides, human β-defensins (hBDs) and cathelicidin LL-37, that participate in the innate host defense. Because IL-18 is produced by keratinocytes and involved in skin diseases in which hBDs and LL-37 are highly expressed, we hypothesized that these peptides would activate keratinocytes to secrete IL-18. We found that hBD-2, -3, and -4 and LL-37, but not hBD-1, activated normal human keratinocytes to secrete IL-18; this secretion reached peak strength at 3 h. In addition, the combination of peptides resulted in a synergistic effect on IL-18 secretion. We also revealed that hBD-2, -3, and -4 and LL-37 increased IL-18 mRNA expression, and that IL-18 secretion was more enhanced in keratinocytes differentiated in vitro with high Ca2+-containing medium. Furthermore, because IL-18 secretion induced by hBDs and LL-37 could not be suppressed by caspase-1 or caspase family inhibitors, and because these peptides failed to increase caspase-1 activity, we suggest that hBD- and LL-37-induced IL-18 secretion is probably via a caspase-1-independent pathway. To determine the molecular mechanism involved, we demonstrated that IL-18 secretion was through p38 and ERK1/2 MAPK pathways, because the inhibitors of p38 and ERK1/2, but not JNK, almost completely nullified IL-18 secretion. Moreover, hBD-2, -3, and -4 and LL-37 could induce the phosphorylation of p38 and ERK1/2, but not JNK. Thus, the ability of hBDs and LL-37 to induce IL-18 secretion by keratinocytes provides a new mechanism for these peptides in innate immunity and an understanding of their role in the pathogenesis of skin disorders.
Polarized Uterine Epithelial Cells Preferentially Present Antigen at the Basolateral Surface: Role of Stromal Cells in Regulating Class II-Mediated Epithelial Cell Antigen Presentation
Authors: Wira Charles R. , Rossoll Richard M. , Young Roger C.
Published: April 2014

To study Ag presentation in the female reproductive tract, DO11.10 TCR transgenic mice specific for the class II MHC-restricted OVA323–339 peptide and nontransgenic BALB/c mice were used. We report here that freshly isolated uterine epithelial cells, uterine stromal, and vaginal APCs present OVA and OVA323–339peptide to naive- and memory T cells, which is reduced when cells are incubated with Abs to CD80 and 86. To determine whether polarized primary epithelial cells present Ags, uterine epithelial cells were cultured on cell inserts in either the upright or inverted position. After reaching confluence, as indicated by high transepithelial resistance (>2000 ohms/well), Ag presentation by epithelial cells incubated with memory T cells and OVA323–339 peptide placed on the basolateral surface (inverted) was 2- to 3-fold greater than that seen with epithelial cells in contact with T cells and peptide on the apical surface (upright). In contrast, whereas freshly isolated epithelial cells process OVA, polarized epithelial cells did not. When epithelial cells grown upright on inserts were incubated with T cells and OVA323–339 peptide, coculture with either hepatocyte growth factor or conditioned stromal medium increased epithelial cell Ag presentation (∼90% higher than controls). These studies indicate that uterine stromal cells produce a soluble factor(s) in addition to a hepatocyte growth factor, which regulates epithelial cell Ag presentation. Overall, these results demonstrate that polarized epithelial cells are able to present Ags and suggest that uterine stromal cells communicate with epithelial cells via a soluble factor(s) to regulate Ag presentation in the uterus.
CD43 Is Required for Optimal Growth Inhibition of Mycobacterium tuberculosis in Macrophages and in Mice
Authors: Randhawa April K. , Ziltener Hermann J. , Merzaban Jasmeen S. , Stokes Richard W.
Published: April 2014

We explored the role of macrophage (Mφ) CD43, a transmembrane glycoprotein, in the pathogenesis of Mycobacterium tuberculosis. Using gene-deleted mice (CD43−/−), we assessed the association of the bacterium with distinct populations of Mφ and found that CD43−/− Mφ bound less M. tuberculosis than CD43+/+ Mφ. Increased infective doses did not abrogate this difference. However, reduced association due to the absence of CD43 could be overcome by serum components. Mφ from heterozygote mice, which express 50% of wild-type CD43, bound more bacteria than CD43−/− but less than CD43+/+, proving that the gene dose of CD43 correlates with binding of M. tuberculosis. Furthermore, the reduced ability of CD43−/− Mφ to bind bacteria was restricted to mycobacterial species. We also found that the survival and replication of M. tuberculosis within Mφ was enhanced significantly in the absence of CD43, making this the first demonstration that the mechanism of mycobacterial entry influences its subsequent growth. Most importantly, we show here that the absence of CD43 in mice aerogenically infected with M. tuberculosis results in an increased bacterial load during both the acute and chronic stages of infection and more rapid development of granulomas, with greater lung involvement and distinctive cellularity.
Depletion of T Cells by Type I Interferon: Differences between Young and Aged Mice
Authors: Jiang Jiu , Gross Diara , Nogusa Shoko , Elbaum Philip , Murasko Donna M.
Published: April 2014

Type I IFN (IFN-I or IFN-αβ) plays an important role in the innate immune response against viral infection. Here we report that a potent inducer of IFN-αβ, polyinosinic-polycytidylic acid [poly(I:C)], led to the depletion of T cells in young, but not aged mice, and that this depletion was limited to central memory, but not effector memory, T cells. Although early activation of T cells in vivo by poly(I:C), as demonstrated by CD69, was not impaired with aging, the expression of active caspase-3 was higher in young compared with aged mice. This depletion of T cells and induction of active caspase-3 in young mice and of CD69 in both young and aged mice by poly(I:C) were blocked by anti-IFN-αβ Ab. Although poly(I:C) stimulated lower circulating levels of IFN-αβ in aged mice, administration of IFN-αβ after poly(I:C) did not induce depletion of T cells in aged mice. These results indicate that IFN-αβ plays a critical role in the depletion of T cells of young mice, and further suggest that the lower level of functional IFN-αβ and decreased induction of active caspase-3 in T cells of aged mice after poly(I:C) may be responsible for the increased resistance of T cells of aged mice to depletion.
Involvement of the Rho-Kinase/Myosin Light Chain Kinase Pathway on Human Monocyte Chemotaxis Induced by ATL-1, an Aspirin-Triggered Lipoxin A4 Synthetic Analog
Authors: Simões Rafael L. , Fierro Iolanda M.
Published: April 2014

Lipoxins (LX) are arachidonic acid metabolites able to induce monocyte chemotaxis in vitro and in vivo. Nonetheless, the signaling pathways mediating this process are yet unclear. In this study, we have investigated the mechanisms associated with human monocyte activation in response to 15-epi-16-(para-fluoro)-phenoxy-LXA4 (ATL-1), a stable 15-epi-LXA4 analog. Our results demonstrate that ATL-1-induced monocyte chemotaxis (10–300 nM) is inhibited by pertussis toxin, suggesting an effect via the G-protein-linked LXA4 receptor. Monocytes stimulated with the analog presented an increased ERK-2 phosphorylation, which was reduced by PD98059, a selective inhibitor of the MEK 1/2 pathway. After exposure of the cells to ATL-1, myosin L chain kinase (MLCK) phosphorylation was evident and this effect was inhibited by PD98059 or Y-27632, a specific inhibitor of Rho kinase. In addition, Y-27632 abolished ERK-2 activation, suggesting that the MAPK pathway is downstream of Rho/Rho kinase in MLCK activation induced by ATL-1. The specific MLCK inhibitor ML-7, as well as Y-27632, abrogated monocyte chemotaxis stimulated by the analog, confirming the central role of the Rho kinase/MLCK pathway on ATL-1 action. Together, these results indicate that ATL-1 acts as a potent monocyte chemoattractant via Rho kinase and MLCK. The present study clarifies some of the mechanisms involved on the activation of monocytes by LXs and opens new avenues for investigation of these checkpoint controllers of inflammation.
Lyn-Deficient Mice Develop Severe, Persistent Asthma: Lyn Is a Critical Negative Regulator of Th2 Immunity
Authors: Beavitt Sarah-Jane E. , Harder Kenneth W. , Kemp Joanna M. , Jones Jessica , Quilici Cathy , Casagranda Franca , Lam Ellen , Turner Debra , Brennan Siobhain , Sly Peter D. , Tarlinton David M. , Anderson Gary P. , Hibbs Margaret L.
Published: April 2014

The etiology of asthma, a chronic inflammatory disorder of the airways, remains obscure, although T cells appear to be central disease mediators. Lyn tyrosine kinase has been implicated as both a facilitator and inhibitor of signaling pathways that play a role in allergic inflammation, although its role in asthma is unclear because Lyn is not expressed in T cells. We show in the present study that Lyn−/− mice develop a severe, persistent inflammatory asthma-like syndrome with lung eosinophilia, mast cell hyperdegranulation, intensified bronchospasm, hyper IgE, and Th2-polarizing dendritic cells. Dendritic cells from Lyn−/− mice have a more immature phenotype, exhibit defective inhibitory signaling pathways, produce less IL-12, and can transfer disease when adoptively transferred into wild-type recipients. Our results show that Lyn regulates the intensity and duration of multiple asthmatic traits and indicate that Lyn is an important negative regulator of Th2 immune responses.
The Inflammatory versus Constitutive Trafficking of Mononuclear Phagocytes into the Alveolar Space of Mice Is Associated with Drastic Changes in Their Gene Expression Profiles
Authors: Srivastava Mrigank , Jung Steffen , Wilhelm Jochen , Fink Ludger , Bühling Frank , Welte Tobias , Bohle Rainer M. , Seeger Werner , Lohmeyer Jürgen , Maus Ulrich A.
Published: April 2014

Mononuclear phagocytes enter the lungs both constitutively to maintain alveolar macrophage and dendritic cell homeostasis, as well as during lung inflammation, where the role of these cells is less well defined. We used a transgenic mouse strain (CX3CR1+/GFP) that harbors a GFP label in circulating monocytes to identify and sort these cells from the vascular and alveolar compartments under both constitutive and acute lung inflammatory conditions. Using nylon arrays combined with real-time RT-PCR for gene expression profiling, we found that flow-sorted, highly purified mononuclear phagocytes recruited to acutely inflamed mouse lungs showed strongly up-regulated mRNA levels of the neutrophil chemoattractants KC, MIP-2, and IP-10, which contrasted with alveolar mononuclear phagocytes that immigrated in steady state. Similar observations were made for the lysosomal cathepsins B, L, and K being strongly up-regulated in mononuclear phagocytes upon recruitment to inflamed lungs but not during constitutive alveolar immigration. Inflammatory elicited mononuclear phagocytes also demonstrated significantly increased mRNA levels of the cytokine TNF-α and the PRR-associated molecules CD14, TLR4, and syndecan-4. Together, inflammatory elicited mononuclear phagocytes exhibit strongly increased neutrophil chemoattractants, lysosomal proteases, and LPS signaling mRNA transcripts, suggesting that these cells may play a major role in acute lung inflammatory processes.
Opposing Regulatory Roles of Complement Factor 5 in the Development of Bleomycin-Induced Pulmonary Fibrosis
Authors: Addis-Lieser Erin , Köhl Jörg , Chiaramonte Mónica G.
Published: April 2014

The mechanisms of idiopathic pulmonary fibrosis pathogenesis, a chronic and progressive interstitial lung disease, remain elusive. The complement system, a crucial arm of the innate immune response, plays a pivotal role in several pathological disorders; however, the contribution of individual complement components to lung fibrosis has not yet been examined. Complement factor 5 (C5) and its cleavage product C5a are critical mediators in inflammatory diseases. Thus, to evaluate the role of C5 in lung fibrosis, we compared congenic C5-sufficient and C5-deficient mice in a well-characterized murine model of bleomycin-induced pulmonary fibrosis. C5-deficient mice had an exaggerated inflammatory phenotype compared with C5-sufficient mice during acute bleomycin-induced lung injury. These findings suggest a protective and anti-inflammatory role for C5, which was linked to the regulation of matrix metalloproteinases involved in cell migration. In contrast, C5 had a detrimental effect during chronic stages of bleomycin-induced injury, indicating a profibrotic role for C5. This deleterious activity for C5 was associated with expression of the fibrogenic cytokine TGF-β1 and matrix metalloproteinase-3, an important mediator in fibroblast contraction. Altogether, our data reveal novel and opposing roles for C5 in both inflammation and tissue repair. Furthermore, these findings provide insight into the development of new therapeutic strategies for idiopathic pulmonary fibrosis patients.
Bacterial Induction of TNF-α Converting Enzyme Expression and IL-6 Receptor α Shedding Regulates Airway Inflammatory Signaling
Authors: Gómez Marisa I. , Sokol Sach H. , Muir Amanda B. , Soong Grace , Bastien Jayson , Prince Alice S.
Published: April 2014

Airway epithelial cells have a major role in initiating inflammation in response to bacterial pathogens. Through the immediate induction of CXCL8 and cytokine expression, polymorphonuclear cells are mobilized and activated to eradicate the infecting organisms. However, the influx of polymorphonuclear cells and the effects of their toxic exoproducts impede respiratory function. We postulated that respiratory epithelial cells must also participate in the regulation of their own proinflammatory signaling. Both Staphylococcus aureus and Pseudomonas aeruginosa were found to potently activate IL-6 expression immediately upon contact with epithelial cells, and by 1 h induced TNF-α converting enzyme (TACE) transcription. By 4 h of bacterial exposure, TACE colocalized with IL-6Rα on the apical surface of airway cells, and by 24 h, soluble IL-6Rα accumulated in the cell culture supernatant. Epithelial IL-6 and soluble IL-6Rα were shown to participate in trans-signaling, interacting with membrane-associated gp130 to activate CCL-2 expression and inhibit additional CXCL8 production. Thus, bacteria are physiological activators of TACE expression, which provides a mechanism to regulate inflammatory signaling that is initiated by airway epithelial cells.
Signaling through Up-Regulated C3a Receptor Is Key to the Development of Experimental Lupus Nephritis
Authors: Bao Lihua , Osawe Iyabo , Haas Mark , Quigg Richard J.
Published: April 2014

Signaling of the C3a anaphylatoxin through its G protein-coupled receptor, C3aR, is relevant in a variety of inflammatory diseases, but its role in lupus nephritis is undefined. In this study, we show that expression of C3aR was significantly increased in prediseased and diseased kidneys of MRL/lpr lupus mice compared with MRL/+ controls. To investigate the role of C3aR in experimental lupus, a small molecule antagonist of C3aR (C3aRa) was administered continuously to MRL/lpr mice from 13 to 19 wk of age. All 13 C3aRa-treated mice survived during the 6-wk treatment compared with 9 of 14 (64.3%) control animals given vehicle (p = 0.019). Relative to controls, C3aRa-treated animals were protected from renal disease as measured by albuminuria (p = 0.040) and blood urea nitrogen (p = 0.021). In addition, there were fewer neutrophils, monocytes, and apoptotic cells in the kidneys of C3aRa-treated mice. C3aRa treatment also led to reduced renal IL-1β and RANTES mRNA and phosphorylated phosphatase and tensin homologue deleted on chromosome 10 protein, whereas the mass of phosphorylated protein kinase B/Akt was increased by C3aRa. Thus, C3aR antagonism significantly reduces renal disease in MRL/lpr mice, which further translates into prolonged survival. These data illustrate that C3aR is relevant in experimental lupus nephritis and may be a target for therapeutic intervention in the human disease.
The Role of Fas in the Immune System Biology of IL-2Rα Knockout Mice: Interplay among Regulatory T Cells, Inflammation, Hemopoiesis, and Apoptosis
Authors: Sharma Rahul , Bagavant Harini , Jarjour Wael N. , Sung Sun-Sang J. , Ju Shyr-Te
Published: April 2014

Introducing lpr mutation prevents early mortality associated with IL-2Rα knockout (KO) mice, prompting us to determine the role of Fas in the immune system biology of IL-2Rα KO mice. Consistent with a defect in CD4+CD25+ regulatory T (Treg) cell expression, spontaneous lymphocyte activation in lymphoid organs was observed in 6-wk-old mice. In 16- to 22-wk-old mice, infiltration of leukocytes was observed in bone marrow, colon, lung, pancreas, lacrimal gland, and salivary gland, but not in heart, thyroid, liver, stomach, small intestine, ovary, and kidney. In the lymphocytes-infiltrated bone marrow, B cell lymphopoiesis was blocked at pro-B to pre-B/immature B stage, culminating in an age-dependent B cell loss in the periphery. These phenotypes were also observed in IL-2Rα KO mice bearing the lpr mutation (DM mice), indicating Treg cell function and the phenotypes attributed directly to Treg cell abnormality are largely Fas-independent. However, anemia and body weight loss were partially prevented, tissue cell apoptosis was inhibited, and lifespan was improved in the DM mice, demonstrating Fas-dependent elements in these processes. Our age-dependent, lifelong analysis of IL-2Rα KO and DM mice supports a CD4+CD25+ Treg cell-based mechanism for the abnormal immune system biology observed in IL-2Rα KO mice and provides a global view of the interplays among Treg cells, multiorgan inflammation, hemopoiesis, and apoptosis.
Reconstitution of EBV Latent but Not Lytic Antigen-Specific CD4+ and CD8+ T Cells after HIV Treatment with Highly Active Antiretroviral Therapy
Authors: Piriou Erwan , Jansen Christine A. , Dort Karel van , De Cuyper Iris , Nanlohy Nening M. , Lange Joep M. A. , van Oers Marinus H. J. , Miedema Frank , van Baarle Debbie
Published: April 2014

The incidence of (EBV-related) malignancies in HIV-infected subjects has declined since the introduction of highly active antiretroviral therapy (HAART). To investigate the effect of HAART on EBV infection, we performed a longitudinal analysis of the T cell response to both a latent and a lytic Ag and EBV viral load in 10 subjects from early in HIV infection up to 5 years after HAART. All individuals responded to HAART by a decline in HIV viral load, a restoration of total CD4+ T cell numbers, and a decline in T cell immune activation. Despite this, EBV load remained unaltered, even after 5 years of therapy, although a decline in both CD4+ and CD8+ T cells specific for the lytic EBV protein BZLF1 suggested a decreased EBV reactivation rate. In contrast, latent EBV Ag EBNA1-specific CD4+ and CD8+ T cell responses were restored after 5 years of treatment to levels comparable to healthy individuals. In two individuals who were treated by HAART late during HIV progression, a lymphoma developed shortly after initiation of HAART, despite restoration of EBV-specific CD4+ and CD8+ T cells. In conclusion, long-term HAART does not alter the EBV DNA load, but does lead to a restoration of EBNA1-specific T cell responses, which might allow better control of EBV-infected cells when applied early enough during HIV infection.
IL-1 Receptor Antagonist-Mediated Therapeutic Effect in Murine Myasthenia Gravis Is Associated with Suppressed Serum Proinflammatory Cytokines, C3, and Anti-Acetylcholine Receptor IgG1
Authors: Yang Huan , Tüzün Erdem , Alagappan Dhivyaa , Yu Xiang , Scott Benjamin G. , Ischenko Alexander , Christadoss Premkumar
Published: April 2014

In myasthenia gravis (MG), TNF and IL-1β polymorphisms and high serum levels of these proinflammatory cytokines have been observed. Likewise, TNF and IL-1β are critical for the activation of acetylcholine receptor (AChR)-specific T and B cells and for the development of experimental autoimmune myasthenia gravis (EAMG) induced by AChR immunization. We tested the therapeutic effect of human recombinant IL-1 receptor antagonist (IL-1ra) in C57BL/6 mice with EAMG. Multiple daily injections of 0.01 mg of IL-1ra administered for 2 wk following two AChR immunizations decreased the incidence and severity of clinical EAMG. Furthermore, IL-1ra treatment of mice with ongoing clinical EAMG reduced the clinical symptoms of disease. The IL-1ra-mediated suppression of clinical disease was associated with suppressed serum IFN-γ, TNF-α, IL-1β, IL-2, IL-6, C3, and anti-AChR IgG1 without influencing total serum IgG. Therefore, IL-1ra could be used as a nonsteroidal drug for the treatment of MG.
Cutting Edge: Critical Role of CXCL16/CXCR6 in NKT Cell Trafficking in Allograft Tolerance
Authors: Jiang Xiaofeng , Shimaoka Takeshi , Kojo Satoshi , Harada Michishige , Watarai Hiroshi , Wakao Hiroshi , Ohkohchi Nobuhiro , Yonehara Shin , Taniguchi Masaru , Seino Ken-ichiro
Published: April 2014

It is well-documented that certain chemokines or their receptors play important roles in the graft rejection. However, the roles of chemokines and their receptors in the maintenance of transplantation tolerance remain unclear. In this study, we demonstrate that blocking of the interaction between the chemokine receptor, CXCR6, highly expressed on Vα14+ NKT cells and its ligand, CXCL16, resulted in the failure to maintain graft tolerance and thus in the induction of acceleration of graft rejection. In a mouse transplant tolerance model, the expression of CXCL16 was up-regulated in the tolerated allografts, and anti-CXCL16 mAb inhibited intragraft accumulation of NKT cells. In vitro experiments further showed that blocking of CXCL16/CXCR6 interaction significantly affected not only chemotaxis but also cell adhesion of NKT cells. These results demonstrate the unique role of CXCL16 and CXCR6 molecules in the maintenance of cardiac allograft tolerance mediated by NKT cells.
Cutting Edge: Polymorphisms in the ICOS Promoter Region Are Associated with Allergic Sensitization and Th2 Cytokine Production
Authors: Shilling Rebecca A. , Pinto Jayant M. , Decker Donna C. , Schneider Daniel H. , Bandukwala Hozefa S. , Schneider Jeffrey R. , Camoretti-Mercado Blanca , Ober Carole , Sperling Anne I.
Published: April 2014

The establishment of ICOS as an important regulator of Th2 development and effector function makes the ICOS locus an attractive candidate for Th2-mediated diseases, such as asthma and allergy. In evaluation of this candidate locus in humans, we identified 11 variants and determined that two in the putative promoter region are significantly associated with allergic sensitization and serum IgE levels. In addition, cultures of activated PBMCs from individuals homozygous for the associated polymorphisms produced increased levels of the Th2 cytokines, IL-4, IL-5, and IL-13, as well as TNF-α compared with controls. One of the polymorphisms, −1413G/A, demonstrated differential NF-κB binding in mobility shift analysis, suggesting that this polymorphism has functional consequences. Overall, these data demonstrate that ICOS is a susceptibility gene for allergic sensitization, perhaps through the promotion of Th2 differentiation.
Activation of Vγ9Vδ2 T Cells by NKG2D
Authors: Rincon-Orozco Bladimiro , Kunzmann Volker , Wrobel Philine , Kabelitz Dieter , Steinle Alexander , Herrmann Thomas
Published: April 2014

Human Vγ9Vδ2 T cells recognize phosphorylated nonpeptide Ags (so called phosphoantigens), certain tumor cells, and cells treated with aminobisphosphonates. NKG2D, an activating receptor for NK cells, has been described as a potent costimulatory receptor in the Ag-specific activation of γδ and CD8 T cells. This study provides evidence that Vγ9Vδ2 T cells may also be directly activated by NKG2D. Culture of PBMC with immobilized NKG2D-specific mAb or NKG2D ligand MHC class I related protein A (MICA) induces the up-regulation of CD69 and CD25 in NK and Vγ9Vδ2 but not in CD8 T cells. Furthermore, NKG2D triggers the production of TNF-α but not of IFN-γ, as well as the release of cytolytic granules by Vγ9Vδ2 T cells. Purified Vγ9Vδ2 T cells kill MICA-transfected RMA mouse cells but not control cells. Finally, DAP10, which mediates NKG2D signaling in human NK cells, was detected in resting and activated Vγ9Vδ2 T cells. These remarkable similarities in NKG2D function in NK and Vγ9Vδ2 T cells may open new perspectives for Vγ9Vδ2 T cell-based immunotherapy, e.g., by Ag-independent killing of NKG2D ligand-expressing tumors.
Redox Equilibrium in Mucosal T Cells Tunes the Intestinal TCR Signaling Threshold
Authors: Reyes Brenda M. Rivera , Danese Silvio , Sans Miquel , Fiocchi Claudio , Levine Alan D.
Published: April 2014

Mucosal immune tolerance in the healthy intestine is typified by lamina propria T cell (LPT) functional hyporesponsiveness after TCR engagement when compared with peripheral blood T cell (PBT). When LPT from an inflamed intestine are activated through TCR cross-linking, their responsiveness is stronger. LPT are thus capable of switching from a tolerant to a reactive state, toggling between high and low thresholds of activation. We demonstrate that in normal LPT global tyrosine phosphorylation upon TCR cross-linking or an increase in intracellular H2O2, an inhibitor of protein tyrosine phosphatases, is muted. Thus, we propose that LPT have a greater reducing capacity than PBT, shifting the balance between kinases and protein tyrosine phosphatases in favor of the latter. Surface γ-glutamyl transpeptidase, an indirect indicator of redox potential, and glutathione are significantly elevated in LPT compared with PBT, suggesting that elevated glutathione detoxifies TCR-induced reactive oxygen species. When glutathione is depleted, TCR-induced LPT tyrosine phosphorylation rises to PBT levels. Conversely, increasing glutathione in PBT attenuates tyrosine phosphorylation. In LPT isolated from inflamed mucosa, TCR cross-linking induces greater phosphorylation, and γ-glutamyl transpeptidase levels are reduced compared with those from autologous noninflamed tissue. We conclude that the high TCR signaling threshold of mucosal T cells is tuned by intracellular redox equilibrium, whose dysregulation may mediate intestinal inflammation.
A Role for IL-27 in Early Regulation of Th1 Differentiation
Authors: Owaki Toshiyuki , Asakawa Masayuki , Morishima Noriko , Hata Kikumi , Fukai Fumio , Matsui Masanori , Mizuguchi Junichiro , Yoshimoto Takayuki
Published: April 2014

IL-27 is a novel IL-6/IL-12 family cytokine that is considered to play a role in Th1 differentiation, whereas the exact role of IL-27 in Th1 differentiation and its molecular mechanism remain unclear. In this study we demonstrate a role for IL-27 in the early regulation of Th1 differentiation and its possible molecular mechanism. The ability of IL-27 to induce Th1 differentiation was most prominent under Th1-polarizing conditions, but without IL-12 in a STAT4- and IFN-γ-independent manner, and was overruled by IL-12 dose dependently. IL-27 rapidly up-regulated the expression of ICAM-1 on naive CD4+ T cells, but not on APCs, and blocking Abs against ICAM-1 and LFA-1 inhibited the IL-27-induced Th1 differentiation. Although IL-27 augmented T-bet expression in naive CD4+ T cells as previously reported, T-bet was not necessary for the IL-27-induced rapid up-regulation of ICAM-1 expression and Th1 differentiation. In contrast, STAT1 was revealed to be required for the rapid up-regulation of ICAM-1 expression and Th1 differentiation by directly mediating the transcriptional enhancement of ICAM-1 gene expression. These results indicate that IL-27 efficiently induces Th1 differentiation under Th1-polarizing conditions, but without IL-12, and that the rapid up-regulation of ICAM-1 expression on naive CD4+ T cells is important for the IL-27-induced Th1 differentiation. Considering that IL-27 is produced from macrophages and DCs earlier than IL-12, the present results suggest that IL-27 may play a pivotal role in early efficient induction of Th1 differentiation until sufficient IL-12 is produced.
Lack of ICAM-1 on APCs during T Cell Priming Leads to Poor Generation of Central Memory Cells
Authors: Parameswaran Neetha , Suresh Radhakrishnan , Bal Vineeta , Rath Satyajit , George Anna
Published: April 2014

ICAM-1/LFA-1 interactions are known to enhance T cell/APC interactions and to promote T cell activation and cytokine secretion. We have analyzed the consequences of ICAM-1-mediated signaling on the generation of memory T cell subsets. We report that lack of ICAM-1 on APCs, but not on T cells, leads to poor T cell activation and proliferation in vitro and in vivo, and that the defect can be compensated by Ag dose, exogenous IL-2, additional costimulation, and by increasing responder T cell density on APCs. ICAM-1-null mice do not respond to immunization with OVA peptide, but immunization with OVA or with Salmonella typhimurium leads to good T cell proliferation 7–10 days later, and clearance of a challenge infection is equivalent to that of wild-type mice. However, when followed over time, recall proliferation and antibacterial immunity decay rapidly in ICAM-1-null mice, while recall cytokine responses are unaffected. The decline in immunity is not related to poor survival of T cells activated on ICAM-1-null APCs, or to poor generation of effectors in ICAM-1-null mice. Phenotypic analysis of T cells stimulated on ICAM-1-null APCs reveals preferential generation of CD44highCD62Llow effector memory cells (TEM) over CD44highCD62Lhigh central memory cells (TCM). Further, while the proportion of naive:memory T cells is similar in unmanipulated wild-type and ICAM-1-null mice, there is an accumulation of TEM cells, and a high TEM: TCM ratio in aging ICAM-1-null mice. Together, the data indicate that signaling through LFA-1 during T cell activation may be involved in commitment to a proliferation-competent memory pool.
Enhancement of Dendritic Cell Antigen Cross-Presentation by CpG DNA Involves Type I IFN and Stabilization of Class I MHC mRNA
Authors: Kuchtey John , Chefalo Peter J. , Gray Reginald C. , Ramachandra Lakshmi , Harding Clifford V.
Published: April 2014

Dendritic cells (DCs) internalize exogenous Ags and process them for cross-presentation by class I MHC (MHC-I) to CD8+ T cells. This processing can occur by transporter for Ag presentation (TAP)-dependent or TAP-independent mechanisms. We observed that CpG DNA enhanced cross-presentation of Ags by Flt-3L-cultured bone marrow-derived murine DCs by a type I IFN (IFN-αβ)-dependent mechanism. Myeloid DCs provided cross-presentation function in this system. Both TAP1 knockout and wild-type DCs showed enhanced cross-presentation when treated with CpG DNA at 26°C, demonstrating that TAP is not essential to this regulatory mechanism, although TAP is an important determinant of MHC-I expression. Enhancement of cross-processing by CpG DNA did not involve increased Ag uptake or proteolysis but did correlate with IFN-αβ-dependent increases in expression of MHC-I mRNA and protein. Increased MHC-I mRNA levels resulted in part from stabilization of MHC-I mRNA, a novel posttranscriptional mechanism for regulation of MHC-I expression. Thus, a major mechanism by which CpG oligodeoxynucleotide increase cross presentation by DCs appears to be an IFN-αβ-mediated increase in MHC-I synthesis.
Novel Ganglioside Antigen Identified by B Cells in Human Medullary Breast Carcinomas: The Proof of Principle Concerning the Tumor-Infiltrating B Lymphocytes
Authors: Kotlan Beatrix , Simsa Peter , Teillaud Jean-Luc , Fridman Wolf Herman , Toth Jozsef , McKnight Michael , Glassy Mark C.
Published: April 2014

The potential tumor-recognizing capacity of B cells infiltrating human breast carcinoma is an important aspect of breast cancer biology. As an experimental system, we used human medullary breast carcinoma because of its heavy B lymphocytic infiltration paralleled to a relatively better prognosis. Ig-rearranged V region VH-JH, Vκ-Jκ, and Vλ-Jλ genes, amplified by RT-PCR of the infiltrating B cells, were cloned, sequenced, and subjected to a comparative DNA analysis. A combinatorial single-chain variable fragment Ab minilibrary was constructed out of randomly selected VH and Vκ clones and tested for binding activity. Our data analysis revealed that some of the VH-JH, Vκ-Jκ, and Vλ-Jλ region sequences were being assigned to clusters with oligoclonal predominance, while other characteristics of the Ab repertoire were defined also. A tumor-restricted binder clone could be selected out of the single-chain variable fragment κ minilibrary tested against membrane fractions of primary breast tumor cells and tumor cell lines, the VH of which proved to be the overexpressed VH3-1 cluster. The specific binding was confirmed by FACS analysis with primary breast carcinoma cells and MDA-MB 231 cell line. ELISA and thin layer chromatography dot-blot experiments showed this target Ag to be a ganglioside D3 (GD3). Our results are a proof of principle about the capacity of B cells infiltrating breast carcinomas to reveal key cancer-related Ags, such as the GD3. GD3-specific Abs may influence tumor cell progression and could be used for further development of diagnostic and/or therapeutic purposes.
Specific Inhibition of c-Raf Activity by Semapimod Induces Clinical Remission in Severe Crohn’s Disease
Authors: Löwenberg Mark , Verhaar Auke , van den Blink Bernt , ten Kate Fibo , van Deventer Sander , Peppelenbosch Maikel , Hommes Daniel
Published: April 2014

There is a substantial need for novel treatment strategies in Crohn’s disease (CD), a chronic relapsing inflammatory disease of the gut. In an earlier study, we reported clinical efficacy of a 2-wk treatment with semapimod (CNI-1493) in 12 patients with therapy resistant CD. The aim of this study was to identify the cellular target underlying semapimod action. In vitro experiments with murine macrophages showed impaired MAPK signaling and decreased cytokine production due to semapimod treatment. In vitro kinase assays revealed c-Raf as a direct molecular target of semapimod, and semapimod did not affect b-Raf enzymatic activity. Immunohistochemistry performed on paired colon biopsies obtained from CD patients (n = 6) demonstrated increased expression of phospho-MEK, the substrate of Raf. Strikingly, phospho-MEK levels were significantly decreased in patients with a good clinical response to semapimod, but no decrease in phospho-MEK expression was observed in a clinically nonresponsive patient. In conclusion, this study identifies c-Raf as a molecular target of semapimod action and suggests that decreased c-Raf activity correlates with clinical benefit in CD. Our observations indicate that c-Raf inhibitors are prime candidates for the treatment of CD.
The Role of ICOS in the CXCR5+ Follicular B Helper T Cell Maintenance In Vivo
Authors: Akiba Hisaya , Takeda Kazuyoshi , Kojima Yuko , Usui Yoshihiko , Harada Norihiro , Yamazaki Tomohide , Ma Juan , Tezuka Katsunari , Yagita Hideo , Okumura Ko
Published: April 2014

ICOS is a new member of the CD28 family of costimulatory molecules that is expressed on activated T cells. Its ligand B7RP-1 is constitutively expressed on B cells. Although the blockade of ICOS/B7RP-1 interaction inhibits T cell-dependent Ab production and germinal center formation, the mechanism remains unclear. We examined the contribution of ICOS/B7RP-1 to the generation of CXCR5+ follicular B helper T (TFH) cells in vivo, which preferentially migrate to the B cell zone where they provide cognate help to B cells. In the spleen, anti-B7RP-1 mAb-treated or ICOS-deficient mice showed substantially impaired development of CXCR5+ TFH cells and peanut agglutinin+ germinal center B cells in response to primary or secondary immunization with SRBC. Expression of CXCR5 on CD4+ T cells was associated with ICOS expression. Adoptive transfer experiments showed that the development of CXCR5+ TFH cells was enhanced by interaction with B cells, which was abrogated by anti-B7RP-1 mAb treatment. The development of CXCR5+ TFH cells in the lymph nodes was also inhibited by the anti-B7RP-1 mAb treatment. These results indicated that the ICOS/B7RP-1 interaction plays an essential role in the development of CXCR5+ TFH cells in vivo.
CC Chemokine Ligand 19 Secreted by Mature Dendritic Cells Increases Naive T Cell Scanning Behavior and Their Response to Rare Cognate Antigen
Authors: Kaiser Andrew , Donnadieu Emmanuel , Abastado Jean-Pierre , Trautmann Alain , Nardin Alessandra
Published: April 2014

For immune responses to take place, naive T cells have to encounter, adhere to, and be stimulated by dendritic cells (DCs). In murine lymph nodes, T cells move randomly and scan the surface of multiple DCs. The factors controlling this motility as well as its consequences remain unclear. We have monitored by video-imaging the earliest steps of the interaction between human DCs and autologous naive CD4+ T cells in the absence of exogenous Ags. Mature, but not immature, DCs were able to elicit small calcium responses in naive T cells along with cell polarization and random motility, resulting in an efficient scanning of DC surfaces by T cells. We identified CCL19 as a key factor enabling all these early T cell responses, including the occurrence of calcium transients. Because this chemokine did not influence the strength of naive T cell adhesion to DCs, enhanced LFA-1 affinity for ICAM-1 was not the main mechanism by which CCL19 increased Ag-independent calcium transients. However, concomitantly to T cell motility, CCL19 augmented the frequency of T cell responses to rare anti-CD3/CD28-coated beads, used as surrogate APCs. We thus propose a new role for CCL19 in humans: by conditioning T cells into a motile DC-scanning state, this chemokine promotes Ag-independent responses and increases the probability of cognate MHC-peptide encounter.
Coordinate Analysis of Murine Immune Cell Surface Markers and Intracellular Phosphoproteins by Flow Cytometry
Authors: Krutzik Peter O. , Clutter Matthew R. , Nolan Garry P.
Published: April 2014

Recently, phosphospecific flow cytometry has emerged as a powerful tool to analyze intracellular signaling events in complex populations of cells because of its ability to simultaneously discriminate cell types based on surface marker expression and measure levels of intracellular phosphoproteins. This has provided novel insights into the cell- and pathway-specific nature of immune signaling. However, we and others have found that the fixation and permeabilization steps necessary for phosphoprotein analysis often negatively affect the resolution of cell types based on surface marker analysis and light scatter characteristics. Therefore, we performed a comprehensive profile of >35 different murine surface marker Abs to understand the effects of fixation and permeabilization on surface Ag staining. Fortuitously, ∼80% of the Abs tested resolved cell populations of interest, although with decreased separation between positive and negative populations and at very different titers than those used on live cells. The other 20% showed either complete loss of separation between populations or loss of intermediately staining populations. We were able to rescue staining of several of these Ags by performing staining after fixation, but before permeabilization, although with limited fluorophore choices. Scatter characteristics of lymphocytes were well retained, but changed dramatically for monocyte and neutrophil populations. These results compile a comprehensive resource for researchers interested in applying phosphospecific flow cytometry to complex populations of cells while outlining steps necessary to successfully apply new surface marker Abs to this platform.
ERK1-Deficient Mice Show Normal T Cell Effector Function and Are Highly Susceptible to Experimental Autoimmune Encephalomyelitis
Authors: Nekrasova Tanya , Shive Carey , Gao Yuehua , Kawamura Kazuyuki , Guardia Rocio , Landreth Gary , Forsthuber Thomas G.
Published: April 2014

T cell activation engages multiple intracellular signaling cascades, including the ERK1/2 (p44/p42) pathway. It has been suggested that ERKs integrate TCR signal strength, and are important for thymocyte development and positive selection. However, the requirement of ERKs for the effector functions of peripheral mature T cells and, specifically, for T cell-mediated autoimmunity has not been established. Moreover, the specific requirements for ERK1 vs ERK2 in T cells have not been resolved. Therefore, we investigated the role of ERK1 in T cell immunity to foreign and self Ags and in the induction of experimental autoimmune encephalomyelitis. The results show that in ERK1-deficient (ERK1−/−) mice, the priming, proliferation, and cytokine secretion of T cells to the self Ag myelin oligodendrocyte glycoprotein peptide 35–55 and to the prototypic foreign Ag OVA are not impaired as compared with wild-type mice. Furthermore, ERK1−/− mice are highly susceptible to experimental autoimmune encephalomyelitis induced with myelin oligodendrocyte glycoprotein peptide 35–55. Finally, thymocyte development and mitogen-induced proliferation were not impaired in ERK1−/− mice on the inbred 129 Sv and C57BL/6 backgrounds. Collectively, the data show that ERK1 is not critical for the function of peripheral T cells in the response to self and foreign Ags and in T cell-mediated autoimmunity, and suggest that its loss can be compensated by ERK2.
Systemic Autoimmune Disease Caused by Autoreactive B Cells That Receive Chronic Help from Ig V Region-Specific T Cells
Authors: Munthe Ludvig André , Corthay Alexandre , Os Audun , Zangani Michael , Bogen Bjarne
Published: April 2014

B cells present BCR V region-derived Id-peptides on their MHC class II molecules to Id-specific CD4+ T cells. Prolonged Id-driven T-B collaboration could cause autoimmune disease, but this possibility is difficult to test in normal individuals. We have investigated whether mice doubly transgenic for an Id+ Ig L chain and an Id-specific TCR develop autoimmune disease. Surprisingly, T cell tolerance was not complete in these mice because a low frequency of weakly Id-reactive CD4+ T cells accumulated with age. These escapee Id-specific T cells provided chronic help for Id+ B cells, resulting in a lethal systemic autoimmune disease including germinal center reactions, hypergammaglobulinemia, IgG autoantibodies, glomerulonephritis, arthritis, skin affection, and inflammatory bowel disease. Inflamed tissues contained foci of Id-driven T-B collaboration, with deposition of IgG and complement. The disease could be transferred with B and T cells. The results demonstrate a novel mechanism for development of autoimmune disease in which self-reactive Id+ B cells receive prolonged help from Id-specific T cells, thus bypassing the need for help from T cells recognizing conventional Ag.