bluuebunny/crossref_metadata_2025 huggingface dataset:
Assembled DJβ Complexes Influence TCRβ Chain Selection and Peripheral Vβ Repertoire
Authors: Carpenter Andrea C. , Yang-Iott Katherine S. , Chao Linda H. , Nuskey Beth , Whitlow Scott , Alt Frederick W. , Bassing Craig H.
Published: April 2009

TCRβ chain repertoire of peripheral αβ T cells is generated through the stepwise assembly and subsequent selection of TCRβ V region exons during thymocyte development. To evaluate the influence of a two-step recombination process on Vβ rearrangement and selection, we generated mice with a preassembled Dβ1Jβ1.1 complex on the Jβ1ω allele, an endogenous TCRβ allele that lacks the Dβ2-Jβ2 cluster, creating the Jβ1DJβ allele. As compared with Jβ1ω/ω mice, both Jβ1DJβ/ω and Jβ1DJβ/DJβ mice exhibited grossly normal thymocyte development and TCRβ allelic exclusion. In addition, Vβ rearrangements on Jβ1DJβ and Jβ1ω alleles were similarly regulated by TCRβ-mediated feedback regulation. However, in-frame VβDJβ rearrangements were present at a higher level on the Jβ1DJβ alleles of Jβ1DJβ/ω αβ T cell hybridomas, as compared with on the Jβ1ω alleles. This bias was most likely due to both an increased frequency of Vβ-to-DJβ rearrangements on Jβ1DJβ alleles and a preferential selection of cells with in-frame VβDJβ exons assembled on Jβ1DJβ alleles during the development of Jβ1DJβ/ω αβ T cells. Consistent with the differential selection of in-frame VβDJβ rearrangements on Jβ1DJβ alleles, the Vβ repertoire of αβ T cells was significantly altered during αβ TCR selection in Jβ1DJβ/ω and Jβ1DJβ/DJβ mice, as compared with in Jβ1ω/ω mice. Our data indicate that the diversity of DJβ complexes assembled during thymocyte development influences TCRβ chain selection and peripheral Vβ repertoire.
IL-7 Receptor Expression Provides the Potential for Long-Term Survival of Both CD62Lhigh Central Memory T Cells and Th1 Effector Cells during Leishmania major Infection
Authors: Colpitts Sara L. , Dalton Nicole M. , Scott Phillip
Published: April 2009

Infection with the intracellular protozoan parasite Leishmania major induces a state of concomitant immunity wherein secondary immunity is dependent upon the persistence of the original pathogen. Our laboratory has described two populations of Leishmania-induced CD4+ T cells that contribute to immunity: CD62Lhigh central memory T (TCM) cells and CD62Llow effector T cells. To determine whether the prosurvival cytokine IL-7 contributes to maintaining these T cells, we examined expression of the IL7R on CD4+ T cells activated during L. major infection. We found that TCM cells present in chronically infected mice expressed high levels of the IL7R. However, in addition to the expression of the IL7R by TCM cells, CD62Llow cells responding to L. major infection expressed the IL7R. Additional experiments revealed that a large percentage of the IL7RhighCD62Llow cells were Th1 cells, based on transcription at the IFN-γ locus and up-regulation of the Th1-promoting transcription factor T-bet. The up-regulation of T-bet did not prevent IL7R expression by L. major-responding CD4+ T cells, nor did the absence of T-bet result in increased IL7R expression. Finally, blockade of IL7R signaling decreased the number of T-bet+CD4+ T cells, reduced IFN-γ production, and inhibited delayed-type hypersensitivity responses in immune mice challenged with L. major, indicating that IL7R signaling contributes to the maintenance of Th1 effector cells. Thus, both TCM and Th1 effector cells can express the IL7R during chronic L. major infection, which provides a potential means for their long-term survival in addition to the presence of persisting parasites.
Impact of Intrinsic Cooperative Thermodynamics of Peptide-MHC Complexes on Antiviral Activity of HIV-Specific CTL
Authors: Motozono Chihiro , Yanaka Saeko , Tsumoto Kouhei , Takiguchi Masafumi , Ueno Takamasa
Published: April 2009

The antiviral activity of HIV-specific CTL is not equally potent but rather is dependent on their specificity. But what characteristic of targeted peptides influences CTL antiviral activity remains elusive. We addressed this issue based on HLA-B35-restricted CTLs specific for two overlapping immunodominant Nef epitopes, VY8 (VPLRPMTY) and RY11 (RPQVPLRPMTY). VY8-specific CTLs were more potently cytotoxic toward HIV-infected primary CD4+ cells than RY11-specific CTLs. Reconstruction of their TCR revealed no substantial difference in their functional avidity toward cognate Ags. Instead, the decay analysis of the peptide-MHC complex (pMHC) revealed that the VY8/HLA-B35 complex could maintain its capacity to sensitize T cells much longer than its RY11 counterpart. Corroboratively, the introduction of a mutation in the epitopes that substantially delayed pMHC decay rendered Nef-expressing target cells more susceptible to CTL killing. Moreover, by using differential scanning calorimetry and circular dichroism analyses, we found that the susceptible pMHC ligands for CTL killing showed interdependent and cooperative, rather than separate or sequential, transitions within their heterotrimer components under the thermally induced unfolding process. Collectively, our results highlight the significant effects of intrinsic peptide factors that support cooperative thermodynamics within pMHC on the efficient CTL killing of HIV-infected cells, thus providing us better insight into vaccine design.
Deletion of PPARγ in Alveolar Macrophages Is Associated with a Th-1 Pulmonary Inflammatory Response
Authors: Malur Anagha , Mccoy Almedia J. , Arce Sergio , Barna Barbara P. , Kavuru Mani S. , Malur Achut G. , Thomassen Mary Jane
Published: April 2009

Peroxisome proliferator-activated receptor γ (PPARγ) is constitutively expressed at high levels in healthy alveolar macrophages, in contrast to other tissue macrophages and blood monocytes. PPARγ ligands have been shown to down-regulate IFN-γ-stimulated inducible NO synthase (iNOS) in macrophages. Because NO is an important inflammatory mediator in the lung, we hypothesized that deletion of alveolar macrophage PPARγ in vivo would result in up-regulation of iNOS and other inflammatory mediators. The loss of PPARγ in macrophages was achieved by crossing floxed (+/+) PPARγ mice and a transgenic mouse containing the CRE recombinase gene under the control of the murine M lysozyme promoter (PPARγKO). Alveolar macrophages were harvested by bronchoalveolar lavage (BAL). Lymphocytes (CD8:CD4 ratio = 2.8) were increased in BAL of PPARγKO vs wild-type C57BL6; p ≤ 0.0001. Both iNOS and IFN-γ expression were significantly elevated (p ≤ 0.05) in BAL cells. Th-1 associated cytokines including IL-12 (p40), MIP-1α (CCL3), and IFN inducible protein-10 (IP-10, CXCL10) were also elevated. IL-4 and IL-17A were not detected. To test whether these alterations were due to the lack of PPARγ, PPARγ KO mice were intratracheally inoculated with a PPARγ lentivirus construct. PPARγ transduction resulted in significantly decreased iNOS and IFN-γ mRNA expression, as well as reduced BAL lymphocytes. These results suggest that lack of PPARγ in alveolar macrophages disrupts lung homeostasis and results in a Th1-like inflammatory response.
Target-Dependent B7-H1 Regulation Contributes to Clearance of Central Nervous Sysyem Infection and Dampens Morbidity
Authors: Phares Timothy W. , Ramakrishna Chandran , Parra Gabriel I. , Epstein Alan , Chen Lieping , Atkinson Roscoe , Stohlman Stephen A. , Bergmann Cornelia C.
Published: April 2009

The neurotropic coronavirus JHM strain of mouse hepatitis virus persists in oligodendroglia despite the presence of virus-specific CD8 T cells. Expression of programmed death 1 (PD-1) and B7-H1 were studied during acute and persistent infection to examine whether this negative regulatory mechanism contributes to CNS viral persistence. The majority of CNS-infiltrating CD8 T cells expressed PD-1, with the highest levels on virus-specific CD8 T cells. Moreover, despite control of infectious virus, CD8 T cells within the CNS of persistently infected mice maintained high PD-1 expression. Analysis of virus-susceptible target cells in vivo revealed that B7-H1 expression was regulated in a cell type-dependent manner. Oligodendroglia and microglia up-regulated B7-H1 following infection; however, although B7-H1 expression on oligodendroglia was prominent and sustained, it was significantly reduced and transient on microglia. Infection of mice deficient in the IFN-γ or IFN-α/β receptor demonstrated that B7-H1 expression on oligodendroglia is predominantly regulated by IFN-γ. Ab blockade of B7-H1 on oligodendroglia in vitro enhanced IFN-γ secretion by virus-specific CD8 T cells. More efficient virus control within the CNS of B7-H1-deficient mice confirmed inhibition of CD8 T cell function in vivo. Nevertheless, the absence of B7-H1 significantly increased morbidity without altering demyelination. These data are the first to demonstrate glia cell type-dependent B7-H1 regulation in vivo, resulting in adverse effects on antiviral CD8 T cell function. However, the beneficial role of PD-1:B7-H1 interactions in limiting morbidity highlights the need to evaluate tissue-specific intervention strategies.
Lipopolysaccharide Potentiates Effector T Cell Accumulation into Nonlymphoid Tissues through TRIF
Authors: McAleer Jeremy P. , Rossi Robert J. , Vella Anthony T.
Published: April 2009

LPS is a natural adjuvant that potentiates Ag-specific T cell survival and Th1 differentiation by stimulating MyD88 and Toll/IL-1R domain-containing adaptor-inducing IFN-β (TRIF) signaling pathways. In this study, we reveal the TRIF pathway is critical for amplifying murine effector T cell accumulation into nonlymphoid tissues following immunization with Ag plus LPS. Although LPS increased the accumulation of splenic T cells in TRIF-deficient mice, markedly fewer T cells were recovered from liver and lung in comparison to wild type. Most of the T cells primed in TRIF-deficient mice failed to up-regulate CXCR3 and had an overall reduced capacity to produce IFN-γ, demonstrating effector T cell differentiation was linked to their migration. To investigate the role of TRIF-dependent cytokines, neutralization studies were performed in wild type mice. Although TNF neutralization reduced T cell numbers, its coneutralization with IL-10 unexpectedly restored the T cells, suggesting the balance between pro- and anti-inflammatory cytokines influences T cell survival rather than their magnitude. To investigate a role for costimulatory molecules, we tested whether the T cell defect in TRIF-deficient mice could be corrected with enforced costimulation. Boosting with a CD40 agonist in addition to LPS restored the effector CD8 T cell response in livers of TRIF-deficient mice while only partially restoring CD4 T cells, suggesting that LPS primes CD8 and CD4 T cell immunity through different mechanisms. Overall, our data support targeting TRIF for vaccines aimed to direct immune responses to nonlymphoid tissues.
Selective Oxidation of DNA Topoisomerase 1 Induces Systemic Sclerosis in the Mouse
Authors: Servettaz Amélie , Goulvestre Claire , Kavian Niloufar , Nicco Carole , Guilpain Philippe , Chéreau Christiane , Vuiblet Vincent , Guillevin Loïc , Mouthon Luc , Weill Bernard , Batteux Frédéric
Published: April 2009

Systemic sclerosis (SSc) is a connective tissue disorder of great clinical heterogeneity. Its pathophysiology remains unclear. Our aim was to evaluate the relative roles of reactive oxygen species (ROS) and of the immune system using an original model of SSc. BALB/c and immunodeficient BALB/c SCID mice were injected s.c. with prooxidative agents (hydroxyl radicals, hypochlorous acid, peroxynitrites, superoxide anions), bleomycin, or PBS everyday for 6 wk. Skin and lung fibrosis were assessed by histological and biochemical methods. Autoantibodies were detected by ELISA. The effects of mouse sera on H2O2 production by endothelial cells and on fibroblast proliferation, and serum concentrations in advanced oxidation protein products (AOPP) were compared with sera from patients with limited or diffuse SSc. We observed that s.c. peroxynitrites induced skin fibrosis and serum anti-CENP-B Abs that characterize limited SSc, whereas hypochlorite or hydroxyl radicals induced cutaneous and lung fibrosis and anti-DNA topoisomerase 1 autoantibodies that characterize human diffuse SSc. Sera from hypochlorite- or hydroxyl radical-treated mice and of patients with diffuse SSc contained high levels of AOPP that triggered endothelial production of H2O2 and fibroblast hyperproliferation. Oxidized topoisomerase 1 recapitulated the effects of whole serum AOPP. SCID mice developed an attenuated form of SSc, demonstrating the synergistic role of the immune system with AOPP in disease propagation. We demonstrate a direct role for ROS in SSc and show that the nature of the ROS dictates the form of SSc. Moreover, this demonstration is the first that shows the specific oxidation of an autoantigen directly participates in the pathogenesis of an autoimmune disease.
An Anti-Vascular Endothelial Growth Factor Receptor 2/Fetal Liver Kinase-1 Listeria monocytogenes Anti-Angiogenesis Cancer Vaccine for the Treatment of Primary and Metastatic Her-2/neu+ Breast Tumors in a Mouse Model
Authors: Seavey Matthew M. , Maciag Paulo C. , Al-Rawi Nada , Sewell Duane , Paterson Yvonne
Published: April 2009

Thirty years after angiogenesis was shown to play an enabling role in cancer, modern medicine is still trying to develop novel compounds and therapeutics to target the tumor vasculature. However, most therapeutics require multiple rounds of administration and can have toxic side effects. In this study, we use anti-angiogenesis immunotherapy to target cells actively involved in forming new blood vessels that support the growth and spread of breast cancer. Targeting a central cell type involved in angiogenesis, endothelial cells, we immunized against host vascular endothelial growth factor receptor 2 to fight the growth of Her-2/neu+ breast tumors. Using the bacterial vector, Listeria monocytogenes (Lm), we fused polypeptides from the mouse vascular endothelial growth factor receptor 2 molecule (fetal liver kinase-1) to the microbial adjuvant, listeriolysin-O, and used Lm to deliver the Ags and elicit potent antitumor CTL responses. Lm-listeriolysin-O-fetal liver kinase-1 was able to eradicate some established breast tumors, reduce microvascular density in the remaining tumors, protect against tumor rechallenge and experimental metastases, and induce epitope spreading to various regions of the tumor-associated Ag Her-2/neu. Tumor eradication was found to be dependent on epitope spreading to HER-2/neu and was not solely due to the reduction of tumor vasculature. However, vaccine efficacy did not affect normal wound healing nor have toxic side effects on pregnancy. We show that an anti-angiogenesis vaccine can overcome tolerance to the host vasculature driving epitope spreading to an endogenous tumor protein and drive active tumor regression.
NF-κB p50 Regulates C/EBPα Expression and Inflammatory Cytokine-Induced Neutrophil Production
Authors: Wang Dehua , Paz-Priel Ido , Friedman Alan D.
Published: April 2009

NF-κB is a key transcriptional inducer of the inflammatory response in mature myeloid cells, and also stimulates cell survival, but its role in immature myeloid cell development has not been well characterized. C/EBPα is required for the development of monocytic and granulocytic myeloid cells from early progenitors, and NF-κB and C/EBPβ cooperatively induce several inflammatory mediators. Having found that C/EBPα binds NF-κB p50 preferentially compared with NF-κB p65, we have now investigated myelopoiesis in nfkb1(−/−) mice lacking NF-κB p50. Absence of p50 leads to a significant reduction in the number of granulocytic progenitors, CFU-granulocyte, obtained with G-CSF or GM-CSF in vitro and reduces neutrophil production in vivo in response to G-CSF, with preservation of monopoiesis in vitro in response to cytokines or LPS. To gain insight into the mechanism underlying reduced granulopoiesis in the absence of NF-κB p50, we assessed the expression of several myeloid regulatory proteins in lineage-negative, immature myeloid cells. Although PU.1, C/EBPβ, and STAT3 levels were unchanged, C/EBPα protein and RNA levels were reduced ∼3-fold in the absence of NF-κB p50. In addition, NF-κB p50 and C/EBPα bound the endogenous C/EBPα promoter in a chromatin immunoprecipitation assay, and NF-κB p50 trans activated the C/EBPα promoter, alone or in cooperation with C/EBPα. Despite reduction of C/EBPα, G-CSFR and M-CSFR levels were maintained in total marrow and in lineage-negative cells. Together, these data indicate that acute inflammation not only activates mature myeloid cells, but also stimulates neutrophil production via NF-κB p50 induction of C/EBPα transcription.
Ym1/2 Promotes Th2 Cytokine Expression by Inhibiting 12/15(S)-Lipoxygenase: Identification of a Novel Pathway for Regulating Allergic Inflammation
Authors: Cai Yeping , Kumar Rakesh K. , Zhou Jiansheng , Foster Paul S. , Webb Dianne C.
Published: April 2009

The Ym1/2 lectin is expressed abundantly in the allergic mouse lung in an IL-13-dependent manner. However, the role of Ym1/2 in the development of allergic airways disease is largely unknown. In this investigation, we show that treatment of mice with anti-Ym1/2 Ab during induction of allergic airways disease attenuated mediastinal lymph node production of IL-5 and IL-13. Ym1/2 was found to be expressed by dendritic cells (DCs) in an IL-13-dependent manner and supplementation of DC/CD4+ T cell cocultures with Ym1/2 enhanced the ability of IL-13−/− DCs to stimulate the secretion of IL-5 and IL-13. Affinity chromatography identified 12/15(S)-lipoxygenase (12/15-LOX) as a Ym1/2-interacting protein and functional studies suggested that Ym1/2 promoted the ability of DCs to stimulate cytokine production by inhibiting 12/15-LOX-mediated catalysis of 12-hydroxyeicosatetraenoic acid (12(S)-HETE). Treatment of DC/CD4+ T cell cultures with the 12/15-LOX inhibitor baicalein enhanced, whereas 12(S)-HETE inhibited the production of Th2 cytokines. Notably, delivery of 12(S)-HETE to the airways of mice significantly attenuated the development of allergic airways inflammation and the production of IL-5 and IL-13. In summary, our results suggest that production of Ym1/2 in response to IL-13 promotes Th2 cytokine production and allergic airways inflammation by inhibiting the production of 12(S)-HETE by 12/15-LOX.
Cross-Presentation by Osteoclasts Induces FoxP3 in CD8+ T Cells
Authors: Kiesel Jennifer R. , Buchwald Zachary S. , Aurora Rajeev
Published: April 2009

Bone is remodeled throughout the life of an animal by the action of osteoclasts, which resorb bone, and osteoblasts, which form new bone. It has recently been recognized that T cells regulate osteoclasts by secreting a number of cytokines including type I and II IFNs and receptor activator of NF-κB ligand. In this study, we show that osteoclasts produce chemokines that recruit CD8+ T cells. Using transgenic OT-I mice, we found that in the presence of OVA, osteoclasts induced the secretion of IL-2, IL-6, and IFN-γ as well as the proliferation of CD8+ T cells. CD8+ T cells activated by osteoclasts expressed FoxP3, CTLA4, and receptor activator of NF-κB ligand. The FoxP3+CD8+ T cells were anergic and suppressed dendritic cell priming of naive responder CD8+ T cells. These results provide two novel observations for osteoimmunology: first, we demonstrate that osteoclasts can cross-present Ags to CD8+ T cells. Second, these data show that osteoclasts are not only regulated by T cells, but they also can regulate T cells forming a feedback control loop. The induction of FoxP3 in T cells through a MHC class I-dependent manner provides a new mechanism to peripherally produce a regulatory T cell. These observations open a new avenue of investigation for the pathogenesis of autoimmune-mediated inflammatory bone diseases.
Developmental Acquisition of the Lyn-CD22-SHP-1 Inhibitory Pathway Promotes B Cell Tolerance
Authors: Gross Andrew J. , Lyandres Julia R. , Panigrahi Anil K. , Prak Eline T. Luning , DeFranco Anthony L.
Published: April 2009

To better understand whether autoimmunity in Lyn-deficient mice arises from compromised central or peripheral B cell tolerance, we examined BCR signaling properties of wild-type and Lyn-deficient B cells at different stages of development. Wild-type mature follicular B cells were less sensitive to BCR stimulation than were immature transitional stage 1 B cells with regard to BCR-induced calcium elevation and ERK MAPK activation. In the absence of Lyn, mature B cell signaling was greatly enhanced, whereas immature B cell signaling was minimally affected. Correspondingly, Lyn deficiency substantially enhanced the sensitivity of mature B cells to activation via the BCR, but minimally affected events associated with tolerance induction at the immature stage. The effects of CD22 deficiency on BCR signaling were very similar in B cells at different stages of maturation. These results indicate that the Lyn-CD22-Src homology region 2 domain-containing phosphatase-1 inhibitory pathway largely becomes operational as B cell mature, and sets a threshold for activation that appears to be critical for the maintenance of tolerance in the B cell compartment.
Phagocytosis in Macrophages Lacking Cbl Reveals an Unsuspected Role for Fcγ Receptor Signaling and Actin Assembly in Target Binding
Authors: Dale Benjamin M. , Traum Daniel , Erdjument-Bromage Hediye , Tempst Paul , Greenberg Steven
Published: April 2009

Fcγ receptor (FcγR)-mediated phagocytosis is known to require tyrosine kinases (TKs). We identified c-Cbl and Cbl-b as proteins that undergo tyrosine phosphorylation during phagocytosis. Cbl-deficient macrophages displayed enhanced FcγR-mediated signaling and phagocytosis. Surprisingly, binding of IgG-coated targets (EIgG) was also enhanced. c-Cbl-deficient macrophages expressed less FcγRIIb, the inhibitory Fcγ receptor; however, this did not account for enhanced target binding. We isolated the function of one Fc receptor isoform, FcγRI, using IgG2a-coated targets (EIgG2a). Cbl-deficient macrophages demonstrated a disproportionate increase in binding EIgG2a, suggesting that signal strength regulates binding efficiency toward opsonized targets. In resting cells, FcγRI colocalized with the Src family TK Hck in F-actin-rich structures, which was enhanced in Cbl-deficient macrophages. Target binding was sensitive to TK inhibitors, profoundly inhibited following depletion of cholesterol, and ablated at 4°C or in the presence of inhibitors of actin polymerization. Sensitivity of EIgG binding to cytoskeletal disruption was inversely proportional to opsonin density. These findings challenge the view that FcγR-mediated binding is a passive event. They suggest that dynamic engagement of TKs and the cytoskeleton enables macrophages to serve as cellular “Venus fly traps”, with the capacity to capture phagocytic targets under conditions of limiting opsonin density.
Cutting Edge: Genetic Characterization of IFN-Producing Killer Dendritic Cells
Authors: Guimont-Desrochers Fanny , Cappello Zachary John , Chagnon Miguel , McDuffie Marcia , Lesage Sylvie
Published: April 2009

The combined phenotypic expression of CD11clowB220+CD122+DX5+ has been used to define a novel cell type termed IFN-producing killer dendritic cells (IKDC). IKDC readily produce IFN-γ and demonstrate spontaneous cytotoxic activity toward tumors, suggesting that a modulation of IKDC number may be beneficial in cancer treatment. We examined various mouse strains and found that IKDC number was highly variable between the different strains. A linkage analysis associated the distal arm of chromosome 7 with variations in IKDC number. The genetic contribution of chromosome 7 to the regulation of IKDC number was confirmed through the use of congenic mice. We further demonstrate that IKDC proportion is regulated by intrinsic hematopoietic factors. We discuss the role of various candidate genes in the regulation of this newly described cell type and its implication in therapy.
Ig-Like Transcript 3 Regulates Expression of Proinflammatory Cytokines and Migration of Activated T Cells
Authors: Chang Chih-Chao , Liu Zhuoru , Vlad George , Qin Haiyan , Qiao Xugang , Mancini Donna M. , Marboe Charles C. , Cortesini Raffaello , Suciu-Foca Nicole
Published: April 2009

Ig-like transcript 3 (ILT3), an inhibitory receptor expressed by APC is involved in functional shaping of T cell responses toward a tolerant state. We have previously demonstrated that membrane (m) and soluble (s) ILT3 induce allogeneic tolerance to human islet cells in humanized NOD/SCID mice. Recombinant sILT3 induces the differentiation of CD8+ T suppressor cells both in vivo and in vitro. To better understand the molecular mechanisms by which ILT3 suppresses immune responses, we have generated ILT3 knockdown (ILT3KD) dendritic cells (DC) and analyzed the phenotypic and functional characteristics of these cells. In this study, we report that silencing of ILT3 expression in DC (ILT3KD DC) increases TLR responsiveness to their specific ligands as reflected in increased synthesis and secretion of proinflammatory cytokines such as IL-1α, IL-1β, and IL-6 and type I IFN. ILT3KD-DC also secretes more CXCL10 and CXCL11 chemokines in response to TLR ligation, thus accelerating T cell migration in diffusion chamber experiments. ILT3KD-DC elicit increased T cell proliferation and synthesis of proinflammatory cytokines IFN-γ and IL-17A both in MLC and in culture with autologous DC pulsed with CMV protein. ILT3 signaling results in inhibition of NF-κB and, to a lesser extent, MAPK p38 pathways in DC. Our results suggest that ILT3 plays a critical role in the in control of inflammation.
A Single Residue, Arginine 65, Is Critical for the Functional Interaction of Leukocyte-Associated Inhibitory Receptor-1 with Collagens
Authors: Tang Xiaobin , Narayanan Sriram , Peruzzi Giovanna , Apara Akintomide , Natarajan Kannan , Margulies David H. , Coligan John E. , Borrego Francisco
Published: April 2009

ITIM-containing receptors play an essential role in modulating immune responses. Leukocyte-associated inhibitory receptor (LAIR)-1, also known as CD305, is an ITIM-containing inhibitory receptor, expressed by all leukocytes, that binds collagens. In this article, we investigate the effect of a conservative R65K mutation on LAIR-1 ligand binding and function. Compared with LAIR-1 wild-type (wt)-expressing cells, LAIR-1 R65K cells show markedly reduced binding to collagen, which correlates with a reduced level of LAIR-1 polarization to the site of interaction with collagens. Both LAIR-1 wt and R65K cells can generate intracellular signals when ligated by anti-LAIR-1 mAb, but only LAIR-1 wt cells respond to collagens or matrigel. In agreement, surface plasmon resonance analyses showed that LAIR-1 R65K protein has markedly reduced avidity for collagen type I compared with LAIR-1 wt. Likewise, LAIR-1 R65K protein has decreased avidity for cells expressing transmembrane collagen XVII. Thus, a single residue, Arg65, is critical for the interaction of LAIR-1 with collagens.
The Role of TCR Specificity and Clonal Competition During Reconstruction of the Peripheral T Cell Pool
Authors: Leitão Catarina , Freitas António A. , Garcia Sylvie
Published: April 2009

Survival of peripheral CD8+ T cells requires TCR interactions with peptide-MHC complexes (p-MHC). In the adult mouse, in the presence of homeostatic mechanisms that strictly control T cell numbers, it is likely that diverse T cell clones may compete for shared patterns of p-MHC. In the present study, we investigate whether the recognition of p-MHC overlaps between different T cell populations and what role does this process plays in the establishment of the peripheral T cell pools. Using an experimental strategy that follows the fate of adoptively transferred polyclonal T cells into RAG0/0 or different TCR transgenic RAG0/0 hosts, we demonstrate that T cells bearing different TCR specificities share identical TCR-specific requirements for survival and lymphopenia driven proliferation (LDP). This interclonal competition applies to both naive and activated/memory T cells and is partially determined by the clone size of the established/resident T cells. However, clonal competition with activated/memory resident T cells impacts differently on the fate of newly produced bone-marrow-derived T cells or adoptively transferred peripheral T cells. Overall, our findings indicate that p-MHC define multiple diverse resource niches that can be shared by T cells from different compartments.
Tumor Regression following DNA Vaccination and Regulatory T Cell Depletion in neu Transgenic Mice Leads to an Increased Risk for Autoimmunity
Authors: Jacob Jennifer B. , Kong Yi-chi M. , Nalbantoglu Ilke , Snower Daniel P. , Wei Wei-Zen
Published: April 2009

Modulation of the immune system to amplify anti-tumor immunity carries the risk of developing autoimmune diseases, including hypothyroidism, as seen with cancer patients undergoing clinical trials for immunotherapeutic regimens. Although there is a tendency to view autoimmunity as a positive indicator for cancer immunotherapy, some autoimmune manifestations can be life-threatening and necessitate prolonged medical intervention or removal from trial. We have established murine test models to assess such risks by monitoring, simultaneously, the immune reactivity to tumor-associated rat erbB-2 (neu) and another self Ag, mouse thyroglobulin (mTg). We previously reported that in wild-type, thyroiditis-resistant BALB/c mice that underwent regression of neu+ TUBO tumors following regulatory T cell (Treg) depletion, immune responses to rat neu and mTg with resultant autoimmune thyroiditis (EAT) were both enhanced. In this study, we tested the balance between tumor immunity and autoimmunity in neu-transgenic BALB NeuT female mice. First, growth and progression of neu+ tumor were compared in neu tolerant mice treated with either CD25 mAb to deplete Tregs and/or DNA vaccination. Only Treg depletion followed by neu DNA vaccination abrogated tolerance to neu, resulting in complete regression of neu+ tumors, as well as long-term protection from spontaneous tumorigenesis in 58% of mice. The risk of developing EAT was then assessed by incorporated mTg immunization with or without LPS as adjuvant. In mice with induced tumor regression, mTg response was enhanced with modest increases in EAT development. Therefore, tumor regression induced by Treg depletion and DNA vaccination can exacerbate autoimmunity, which warrants close monitoring during immunotherapy.
World Malaria Day 2009: What Malaria Knows about the Immune System That Immunologists Still Do Not
Authors: Pierce Susan K. , Miller Louis H.
Published: April 2009

Malaria kills >1 million children each year, and there is little doubt that an effective vaccine would play a central role in preventing these deaths. However, the strategies that proved so successful in developing the vaccines we have today may simply not be adequate to confront complex, persistent infectious diseases, including malaria, AIDS, and tuberculosis. We believe that the development of a highly effective vaccine will require a better understanding of several features of the immune response to malaria. At the top of the list is the complex and ancient relationship between the parasite that causes malaria and the immune system that enables the parasite to persist in an otherwise functional immune system. A close second is the antigenic targets in malaria and how to overcome the enormous polymorphism of these targets. Meeting these challenges represents a call to arms of basic immunologists to advance our knowledge of malaria immunity.
The Regulation of Liver Cell Survival by Complement
Authors: Markiewski Maciej M. , DeAngelis Robert A. , Strey Christoph W. , Foukas Periklis G. , Gerard Craig , Gerard Norma , Wetsel Rick A. , Lambris John D.
Published: April 2009

Complement effectors are known to contribute to host cell injury in several inflammatory diseases. Contrary to this paradigm, in this study utilizing surgical liver resection (partial hepatectomy) in various complement-deficient mice as a model, we have demonstrated that complement anaphylatoxins C3a and C5a are required for the survival of liver cells during regeneration. The mechanisms of these cytoprotective functions of complement were related to the regulation of IL-6 and TNF production or release after liver resection. Disturbances in the cytokine milieu, induced by a loss of complement activity, were found to alter prosurvival signaling, including the IL-6/STAT3 and PI3K/Akt/mammalian target of rapamycin pathways. In conclusion, this study documents functions of complement proteins as prosurvival factors that, through their interactions with cytokines, inhibit apoptotic signaling in proliferating cells of epithelial origin.
CD59 Blockade Enhances Antigen-Specific CD4+ T Cell Responses in Humans: A New Target for Cancer Immunotherapy?
Authors: Sivasankar Baalasubramanian , Longhi M. Paula , Gallagher Kathleen M. E. , Betts Gareth J. , Morgan B. Paul , Godkin Andrew J. , Gallimore Awen M.
Published: April 2009

CD59, a broadly expressed GPI-anchored molecule, regulates formation of the membrane attack complex of the complement cascade. We previously demonstrated that mouse CD59 also down-modulates CD4+ T cell activity in vivo. In this study, we explored the role of CD59 on human CD4+ T cells. Our data demonstrate that CD59 is up-regulated on activated CD4+ T cells and serves to down-modulate their activity in response to polyclonal and Ag- specific stimulation. The therapeutic potential of this finding was explored using T cells isolated from colorectal cancer patients. The findings were striking and indicated that blockade of CD59 significantly enhanced the CD4+ T cell response to two different tumor Ags. These data highlight the potential for manipulating CD59 expression on T cells for boosting weak immune responses, such as those found in individuals with cancer.
Id3 Restricts the Developmental Potential of γδ Lineage during Thymopoiesis
Authors: Ueda-Hayakawa Ikuko , Mahlios Josh , Zhuang Yuan
Published: April 2009

Most T cell progenitors develop into the αβ T cell lineage with the exception of a small fraction contributing to the γδ lineage throughout postnatal life. T cell progenitors usually commit to the αβ lineage upon the expression of a fully rearranged and functional TCRβ gene, and most cells that fail to produce a functional TCRβ-chain will die instead of adopting the alternative γδ T cell fate. What prevents these cells from continuing TCRγ rearrangement and adopting the γδ T cell fate is not known. In this study, we show that functional loss of Id3 results in a significant increase of γδ T cell production from progenitor cells undergoing TCRβ rearrangement. The enhanced γδ T cell development correlated with increased TCRγ gene rearrangement involving primarily Vγ1.1 in Id3 deficient mice. We further show that Id3 deficiency promotes γδ T cell production in a manner independent of TCRβ-chain expression. Our data indicates that Id3 suppresses Vγ1.1 rearrangement and γδ lineage potential among T cell progenitors that have completed TCRβ gene rearrangement without producing a functional TCRβ protein.
IL-23 Drives Pathogenic IL-17-Producing CD8+ T Cells
Authors: Ciric Bogoljub , El-behi Mohamed , Cabrera Rosalyn , Zhang Guang-Xian , Rostami Abdolmohamad
Published: April 2009

IL-17-producing CD8+ T cells (Tc17) appear to play a role in a range of conditions, such as autoimmunity and cancer. Thus far, Tc17 cells have been only marginally studied, resulting in a paucity of data on their biology and function. We demonstrate that Tc17 and Th17 cells share similar developmental characteristics, including the previously unknown promoting effect of IL-21 on Tc17 cell differentiation and IL-23-dependent expression of IL-22. Both STAT1 and STAT4 are required for optimal development of Tc17 cells and maximal secretion of cytokines. Tc17 cells are cytotoxic, and they can be either pathogenic or nonpathogenic upon adoptive transfer in the model of autoimmune diabetes. Tc17 cells treated with TGF-β1 plus IL-6 are not diabetogenic, whereas IL-23-treated cells potently induce the disease. IL-17A and IL-17F are necessary but not sufficient for diabetes induction by Tc17 cells. Tc17 cells treated with TGF-β1 plus IL-6 or IL-23 likely differ in pathogenicity due to their disparate capacity to attract other immune cells and initiate inflammation.
Transcriptome Profiling and Functional Analyses of the Zebrafish Embryonic Innate Immune Response to Salmonella Infection
Authors: Stockhammer Oliver W. , Zakrzewska Anna , Hegedûs Zoltán , Spaink Herman P. , Meijer Annemarie H.
Published: April 2009

Due to the clear separation of innate immunity from adaptive responses, the externally developing zebrafish embryo represents a useful in vivo model for identification of innate host determinants of the response to bacterial infection. Here we performed a time-course transcriptome profiling study and gene ontology analysis of the embryonic innate immune response to infection with two model Salmonella strains that elicit either a lethal infection or an attenuated response. The transcriptional response to infection with both the lethal strain and the avirulent LPS O-Ag mutant strain showed clear conservation with host responses detected in other vertebrate models and human cells, including induction of genes encoding cell surface receptors, signaling intermediates, transcription factors, and inflammatory mediators. Furthermore, our study led to the identification of a large set of novel immune response genes and infection markers, the future functional characterization of which will support vertebrate genome annotation. From the time series and bacterial strain comparisons, matrix metalloproteinase genes, including mmp9, were among the most consistent infection-responsive genes. Purified Salmonella flagellin also strongly induced mmp9 expression. Using knockdown analysis, we showed that this gene was downstream of the zebrafish homologs of the flagellin receptor TLR5 and the adaptor MyD88. Additionally, flagellin-mediated induction of other inflammation markers, including il1b, il8, and cxcl-C1c, was reduced upon Tlr5 knockdown as well as expression of irak3, a putative negative TLR pathway regulator. Finally, we showed that induction of il1b, mmp9, and irak3 requires Myd88-dependent signaling, while ifn1 and il8 were induced Myd88 independently during Salmonella infection.
Mechanism Regulating Reactive Oxygen Species in Tumor-Induced Myeloid-Derived Suppressor Cells
Authors: Corzo Cesar A. , Cotter Matthew J. , Cheng Pingyan , Cheng Fendong , Kusmartsev Sergei , Sotomayor Eduardo , Padhya Tapan , McCaffrey Thomas V. , McCaffrey Judith C. , Gabrilovich Dmitry I.
Published: April 2009

Myeloid-derived suppressor cells (MDSC) are a major component of the immune suppressive network described in cancer and many other pathological conditions. Recent studies have demonstrated that one of the major mechanisms of MDSC-induced immune suppression is mediated by reactive oxygen species (ROS). However, the mechanism of this phenomenon remained unknown. In this study, we observed a substantial up-regulation of ROS by MDSC in all of seven different tumor models and in patients with head and neck cancer. The increased ROS production by MDSC is mediated by up-regulated activity of NADPH oxidase (NOX2). MDSC from tumor-bearing mice had significantly higher expression of NOX2 subunits, primarily p47phox and gp91phox, compared with immature myeloid cells from tumor-free mice. Expression of NOX2 subunits in MDSC was controlled by the STAT3 transcription factor. In the absence of NOX2 activity, MDSC lost the ability to suppress T cell responses and quickly differentiated into mature macrophages and dendritic cells. These findings expand our fundamental understanding of the biology of MDSC and may also open new opportunities for therapeutic regulation of these cells in cancer.
Natural Graphite
Authors: Kalyoncu Rustu S. , Taylor Harold A.
Published: April 2009

Graphite is the soft, gray‐black form of crystalline carbon; the other forms of crystalline carbon are diamond and fullerenes. Graphite occurs naturally as crystalline flake, mined as flat hexagonal flakes in usually weathered metamorphic rock, as amorphous in former coal beds subjected to additional heat and pressure, and as lump or high‐crystalline graphite occurring in hydrothermal veins in its host rock in Sri Lanka. Natural graphite is not mined in the United States. It is usually mined by open‐pit and beneficiated (crystalline flake) by flotation. Its principal sources are China and Brazil, then Canada, Mexico, and Madagascar.

Flake graphite can also be recovered from a steelmaking waste called kish. Competition within China sets the world price. Natural graphite is used principally in graphite‐containing refractories for steelmaking that are thermally conductive and resist high temperatures, in automotive brake linings, and in batteries, pencils, lubricants, and crucibles. It may come to be used in fuel cells to power nonpolluting vehicles.
The Periodic Table.Its Story and Its Significance. Von Eric R. Scerri.
Authors: Schwarz W. H. Eugen
Published: April 2009

Oxford University Press, Oxford 2006. 346 S., geb., 29.00 €.—ISBN 978‐0‐19‐530573‐6

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Handbook Of Heterogeneous Catalysis.Band 1–8. 2., vollständig überarbeitete und erweiterte Auflage. Herausgegeben von G. Ertl, H. Knözinger, F. Schüth und J. Weitkamp.
Authors: Thomas John Meurig
Published: April 2009

Wiley‐VCH, Weinheim 2008. 3966 S., geb., 1999.00 €.—ISBN 978‐3527312412

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The Periodic Table.Its Story and Its Significance. By Eric R. Scerri.
Authors: Schwarz W. H. Eugen
Published: April 2009

Oxford University Press, Oxford 2006. 346 pp., hardcover € 29.00.—ISBN 978‐0‐19‐530573‐6

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Handbook Of Heterogeneous Catalysis. 2., completely revised and enlarged Edition. Vol. 1–8. Edited by G. Ertl, H. Knözinger, F. Schüth, and J. Weitkamp.
Authors: Thomas John Meurig
Published: April 2009

Wiley‐VCH, Weinheim 2008. 3966 pp., hardcover € 1999.00.—ISBN 978‐3527312412

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Cover Picture: Total Synthesis and Absolute Configuration of the Bisanthraquinone Antibiotic BE‐43472B (Angew. Chem. Int. Ed. 19/2009)
Authors: Nicolaou K. C. , Lim Yee Hwee , Becker Jochen
Published: April 2009

A cascade sequence featuring a Diels–Alder reaction, a lactolization, and an SN(Ar)‐type substitution forms the core of the bisanthraquinone antibiotic BE‐43472B in its first total synthesis, which K. C. Nicolaou et al. describe in their Communication on page 3444 ff. The background of the cover picture is a photograph of Ecteinascidia turbinata (courtesy of John Easley Photography), the marine source of the streptomyces strain producing this antibiotic.

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A cascade sequence featuring a Diels–Alder reaction, a lactolization, and an SN(Ar)‐type substitution forms the core of the bisanthraquinone antibiotic BE‐43472B in its first total synthesis, which K. C. Nicolaou et al. describe in their Communication on page 3444 ff. The background of the cover picture is a photograph of Ecteinascidia turbinata (courtesy of John Easley Photography), the marine source of the streptomyces strain producing this antibiotic.

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Toward automated peak resolution in complete GC × GC–TOFMS chromatograms by PARAFAC
Authors: Hoggard Jamin C. , Siegler W. Christopher , Synovec Robert E.
Published: April 2009

We have previously developed automated PARAFAC methods for resolving peaks from small subsections of data, obtained using comprehensive multidimensional gas chromatography with mass spectral detection (GC × GC–TOFMS). Herein, we build upon those previous methods and present a new method for resolving peaks across much larger sections or even entire GC × GC–TOFMS chromatograms using PARAFAC in an automated fashion. In addition, the method presented is demonstrated on three GC × GC–TOFMS data sets: (1) a complete chromatogram of a test mixture of 32 compounds, (2) several compounds spiked into a diesel sample at two known concentrations and (3) a large section of the chromatogram of the headspace of a urine sample collected by solid phase microextraction (SPME), i.e. containing volatile metabolites. The results of these analyses show that the presented method resolves peaks (including overlapping peaks) and provides useful quantitative and identification information as long as some care is taken in the selection of parameters (such as the size of subsections to be analyzed individually by PARAFAC). Analysis time using PARAFAC remains a challenge, but a technique for reducing the amount of time is demonstrated and future possibilities for greatly reducing the analysis time are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Lehrerfortbildung im Bereich Chemie – eine Chance für die Unterrichtsentwicklung an der Hauptschule
Authors: Barth Ulrich , Pfeifer Peter
Published: April 2009

Vor dem Hintergrund der PISA‐Studien [1] gewinnen Anstrengungen zur Schul‐ und Unterrichtsentwicklung weitere Aktualität. Ein wichtiges Instrument zur Unterrichtsentwicklung ist dabei die Lehrerfortbildung, die sich mit ihrem Fortbildungsangebot zumeist an Experten wendet, d.h. Zielgruppe sind Lehrkräfte, die das entsprechende Unterrichtsfach studiert haben und auch Unterrichtserfahrung mitbringen. Ziel der Lehrerfortbildung muss in diesem Fall sein, den Lehrkräften neuere Entwicklungen auf dem Gebiet der Fachwissenschaft sowie der Fachdidaktik in „ihrem Fach”︁ nahe zu bringen, sie also auf „dem Laufenden”︁ zu halten.
Übergangsmetallkomplexe in der Organischen Chemie
Authors: Butenschön Holger
Published: April 2009

Die Metallorganische Chemie ist ein Teilgebiet der Chemie, welches zwischen der Organischen und der Anorganischen Chemie angesiedelt ist. Während die Organische Chemie definitionsgemäß die Chemie der Verbindungen des Kohlenstoffs ist und die Anorganische Chemie unter anderem die Chemie der Metalle und deren Verbindungen zum Gegenstand hat, verknüpft die Metallorganische Chemie Teile dieser beiden Disziplinen, indem Verbindungen bearbeitet werden, die neben organischen Teilen auch Metalle enthalten. Innerhalb der Metallorganischen Chemie werden üblicherweise Verbindungen der Hauptgruppenmetalle wie Triethylaluminium oder Grignard‐Reagenzien von den Übergangsmetallkomplexen unterschieden. Letztere sind der Gegenstand dieses Aufsatzes.

Übergangsmetallkomplexe bestehen aus einem oder mehreren Metallatomen und daran gebundenen, oft organischen Liganden. Durch die Bindung an ein Metallatom verändern sich die chemischen Eigenschaften der Liganden und des Metallzentrums. Dementsprechend werden hier nach einer kurzen Einführung in die Stoffklasse der Übergangsmetallkomplexe zunächst einige ausgewählte Reaktionen an den Liganden von Übergangsmetallkomplexen behandelt. Es folgen stöchiometrische Reaktionen am Metallatom. Danach wird der wichtige und anwendungsnahe Bereich der Übergangsmetallkatalyse an einigen aktuellen Beispielen vorgestellt. Den Abschluss bildet eine kurze Zusammenfassung. In einem Einschub werden die Herstellung des Ferrocens sowie seine Acetylierung als Möglichkeit für die Berücksichtigung metallorganischer Verbindungen im Chemieunterricht vorgestellt.