bluuebunny/crossref_metadata_2025 huggingface dataset:
The Common Myelolymphoid Progenitor: A Key Intermediate Stage in Hemopoiesis Generating T and B Cells
Authors: Lu Min , Kawamoto Hiroshi , Katsube Yoshihiro , Ikawa Tomokatsu , Katsura Yoshimoto
Published: April 2014

We have previously shown that the common progenitors for myeloid, T, and B cell lineages are enriched in the earliest population of murine fetal liver. However, it remained unclear whether such multipotent progenitors represent the pluripotent progenitors capable of generating all hemopoietic cells or they also comprise progenitors restricted to myeloid, T, and B cell lineages. To address this issue, we have developed a new clonal assay covering myeloid, erythroid, T, and B cell lineages, and using this assay the developmental potential of individual cells in subpopulations of lineage marker-negative (Lin−) c-kit+ murine fetal liver cells was investigated. We identified the progenitor generating myeloid, T, and B cells, but not erythroid cells in the Sca-1high subpopulation of Lin-c-kit+ cells that can thus be designated as the common myelolymphoid progenitor (CMLP). Common myeloerythroid progenitors were also detected. These findings strongly suggest that the first branching point in fetal hemopoiesis is between the CMLP and common myeloerythroid progenitors. T and B cell progenitors may be derived from the CMLP through the previously identified myeloid/T and myeloid/B bipotent stages, respectively.
Expression of Human Complement Receptor Type 2 (CD21) in Mice During Early B Cell Development Results in a Reduction in Mature B Cells and Hypogammaglobulinemia
Authors: Marchbank Kevin J. , Kulik Liudmila , Gipson Matthew G. , Morgan B. Paul , Holers V. Michael
Published: April 2014

Complement receptor (CR) type 2 (CR2/CD21) is normally expressed only during the immature and mature stages of B cell development. In association with CD19, CR2 plays an important role in enhancing mature B cell responses to foreign Ag. We used a murine Vλ2 promoter/Vλ2–4 enhancer minigene to develop transgenic mice that initiate expression of human CR2 (hCR2) during the CD43+CD25− late pro-B cell stage of development. We found peripheral blood B cell numbers reduced by 60% in mice expressing high levels of hCR2 and by 15% in mice with intermediate receptor expression. Splenic B cell populations were altered with an expansion of marginal zone cells, and basal serum IgG levels as well as T-dependent immune responses were also significantly decreased in transgenic mice. Mice expressing the highest levels of hCR2 demonstrated in the bone marrow a slight increase in B220intCD43+CD25− B cells in association with a substantial decrease in immature and mature B cells, indicative of a developmental block in the pro-B cell stage. These data demonstrate that stage-specific expression of CR2 is necessary for normal B cell development, as premature receptor expression substantially alters this process. Alterations in B cell development are most likely due to engagement of pre-B cell receptor-mediated or other regulatory pathways by hCR2 in a CD19- and possibly C3 ligand-dependent manner.
Induction of Tumor-Reactive CTL by C-Side Chain Variants of the CTL Epitope HER-2/neu Protooncogene (369-377) Selected by Molecular Modeling of the Peptide: HLA-A2 Complex
Authors: Castilleja Agapito , Carter Darrick , Efferson Clay L. , Ward Nancy E. , Kawano Kouichiro , Fisk Bryan , Kudelka Andrzej P. , Gershenson David M. , Murray James L. , O’Brian Catherine A. , Ioannides Constantin G.
Published: April 2014

To design side chain variants for modulation of immunogenicity, we modeled the complex of the HLA-A2 molecule with an immunodominant peptide, E75, from the HER-2/neu protooncogene protein recognized by CTL. We identified the side chain orientation of E75. We modified E75 at the central Ser5 (E75 wild-type), which points upward, by removing successively the HO (variant S5A) and the CH2-OH (variant S5G). Replacement of the OH with an aminopropyl (CH2)3-NH3 (variant S5K) maintained a similar upward orientation of the side chain. S5A and S5G were stronger stimulators while S5K was a weaker stimulator than E75 for induction of lytic function, indicating that the OH group and its extension hindered TCR activation. S5K-CTL survived longer than did CTL induced by E75 and the variants S5A and S5G, which became apoptotic after restimulation with the inducer. S5K-CTL also recognized E75 endogenously presented by the tumor by IFN-γ production and specific cytolysis. S5K-CTL expanded at stimulation with E75 or with E75 plus agonistic anti-Fas mAb. Compared with S5K-CTL that had been restimulated with the inducer S5K, S5K-CTL stimulated with wild-type E75 expressed higher levels of E75+ TCR and BCL-2. Activation of human tumor-reactive CTL by weaker agonists than the nominal Ag, followed by expansion with the nominal Ag, is a novel approach to antitumor CTL development. Fine tuning of activation of tumor-reactive CTL by weak agonists, designed by molecular modeling, may circumvent cell death or tolerization induced by tumor Ag, and thus, may provide a novel approach to the rational design of human cancer vaccines.
Differential Functions of IL-4 Receptor Types I and II for Dendritic Cell Maturation and IL-12 Production and Their Dependency on GM-CSF
Authors: Lutz Manfred B. , Schnare Markus , Menges Mauritius , Rössner Susanne , Röllinghoff Martin , Schuler Gerold , Gessner André
Published: April 2014

Little is known about the distinct roles of the two types of IL-4R on DC. Here we report that IL-4 and IL-13 are able to promote DC maturation, as evaluated by up-regulation of MHC class II and costimulatory molecules, when the concentration of GM-CSF is relatively lower than the dose of IL-4 or IL-13. In addition, under these conditions both cytokines enable DC to respond to maturation stimuli such as bacterial products or proinflammatory cytokines. Both IL-4 and IL-13 act synergistically with weak maturation stimuli such as TNF-α or CD40. The IL-4R signaling for DC maturation requires the IL-4R α-chain and STAT6, but not Janus kinase 3, indicating that IL-4R type II signaling is preferentially responsible for these effects. In contrast, the production of IL-12 p70, but not IL-10 and TNF, induced by microbial products was enhanced only by IL-4, not by IL-13 or Y119D, a selective type II IL-4R agonist, in vitro and in vivo. This enhancement was dependent on the presence of Janus kinase 3, indicating that this function is exclusively mediated by the type I IL-4R. In short, we discerned the individual roles of the two IL-4R types on DC function, showing that IL-4R type I promotes IL-12 secretion independently of GM-CSF concentration, while IL-4R type II promotes the up-regulation of MHC class II and costimulatory surface markers in a GM-CSF concentration-dependent manner.
IL-21 Up-Regulates the Expression of Genes Associated with Innate Immunity and Th1 Response
Authors: Strengell Mari , Sareneva Timo , Foster Don , Julkunen Ilkka , Matikainen Sampsa
Published: April 2014

IL-21 is a recently characterized T cell-derived cytokine that regulates NK and T cell function. IL-21R shares the common γ-chain (γc) with the receptors for IL-2, IL-4, IL-7, IL-9, and IL-15. Despite the same γc, these cytokines have different effects on diverse cells. In this study, we have studied IL-15- and IL-21-induced gene expression in human primary NK and T cells and the NK-92 cell line. Both IL-15 and IL-21 rapidly induced mRNA synthesis for IFN-γ, T-bet, IL-2Rα, IL-12Rβ2, IL-18R, and myeloid differentiation factor 88 (MyD88), the genes that are important in activating innate immunity and Th1 response. IL-15 induced STAT5 DNA binding to the IL-2Rα IFN-γ-activated sequence (GAS), MyD88 GAS, and c-sis-inducible elements, whereas IL-21 induced STAT3 DNA binding to MyD88 GAS and c-sis-inducible elements. IL-21-induced STAT3 activation was verified by immunoprecipitation and Western blotting with anti-phosphotyrosine Ab. In addition, pretreatment of NK-92 cells with IL-15 or IL-21 strongly enhanced IL-12-induced STAT4 DNA binding to IL-2Rα GAS. The induction of IFN-γ, T-bet, IL-12Rβ2, and IL-18R gene expression in NK cells, along with STAT3 activation, suggests that IL-21 is involved in the activation of innate immune responses. Moreover, the enhanced transcription of these genes in T cells establishes a significant role for IL-21 also in the Th1 response.
IL-12 Provides Proliferation and Survival Signals to Murine CD4+ T Cells Through Phosphatidylinositol 3-Kinase/Akt Signaling Pathway
Authors: Yoo Jae Kwang , Cho Jae Ho , Lee Seung Woo , Sung Young Chul
Published: April 2014

IL-12 is a pleiotropic cytokine that plays an important role in innate and adaptive immunity. IL-12 induces T cell proliferation and IFN-γ secretion from activated T cells. It was also reported that IL-12 prevents apoptosis of CD4+ T cells. However, the signaling mechanism that regulates these IL-12-induced responses is poorly understood yet. In this study, we demonstrated that IL-12 activates phosphatidylinositol 3-kinase (PI3K)/Akt pathway in murine CD4+ T cells, and that this signaling pathway is required for IL-12-induced T cell proliferation and antiapoptotic function, but not for IFN-γ induction. Through PI3K/Akt pathway, IL-12 up-regulates the expression of cell cycle-related molecule such as cyclin D3, and antiapoptotic molecules such as Bcl-2 and cellular inhibitors of apoptosis proteins-2, followed by down-regulation of active caspase-3. These results suggest that PI3K/Akt pathway is critical for mediating IL-12-induced CD4+ T cell responses such as T cell proliferation and survival.
T Cells Primed byLeishmania majorInfection Cross-React with Alloantigens and Alter the Course of Allograft Rejection
Authors: Pantenburg Birte , Heinzel Fred , Das Lopamudra , Heeger Peter S. , Valujskikh Anna
Published: April 2014

Alloreactive T lymphocytes can be primed through direct presentation of donor MHC:peptide complexes on graft cells and through indirect presentation of donor-derived determinants expressed by recipient APCs. The large numbers of determinants on an allograft and the high frequency of the alloreactive repertoire has further led to speculation that exposure to environmental Ags may prime T cells that cross-react with alloantigens. We sought to develop a model in which to test this hypothesis. We found that CD4+ T cells obtained from C57BL/6 (B6) mice that clinically resolved Leishmania major infection exhibited statistically significant cross-reactivity toward P/J (H-2p) Ags compared with the response to other haplotypes. B6 animals that were previously infected with L. major specifically rejected P/J skin grafts with second set kinetics compared with naive animals. Although donor-specific transfusion combined with costimulatory blockade (anti-CD40 ligand Ab) induced prolonged graft survival in naive animals, the same treatment was ineffective in mice previously infected with L. major. The studies demonstrate that cross-reactive priming of alloreactive T cells can occur and provide direct evidence that such T cells can have a significant impact on the outcome of an allograft. The results have important implications for human transplant recipients whose immune repertoires may contain cross-reactively primed allospecific T cells.
In Vivo Priming Of HIV-Specific CTLs Determines Selective Cross-Reactive Immune Responses Against Poorly Immunogenic HIV-Natural Variants
Authors: Boissonnas Alexandre , Bonduelle Olivia , Antzack Ariane , Lone Yu-Chun , Gache Cécile , Debre Patrice , Autran Brigitte , Combadière Behazine
Published: April 2014

Degeneracy of the TCR repertoire might allow for cross-recognition of epitope variants. However, it is unclear how the first encounter with HIV Ags determines recognition of emerging epitope variants. This question remains crucial in the choice of HIV vaccine sequences given the virus variability. In this study, we individualized nine natural mutations within an HIV-Nef180–189 epitope selected from several HIV-infected individuals. These variants of Nef180–189 sequence display slightly different HLA-A2 binding capacities and stabilities and we have shown that only two induced a strong CTL response in vivo in HLA-A2 transgenic mice after a single injection. We demonstrated that priming with these two immunogenic variants generated a specific pattern of cross-reactive CTL repertoire directed against poorly immunogenic peptides. Thus, the range of peptide variants recognized by HIV-specific CTL depends upon the Ag encountered during primary immunization of CD8 lymphocytes. These data have practical implications in the development of cross-reactive vaccines against HIV.
Lymphoid Enhancer-Binding Factor-1 Binds and Activates the Recombination-Activating Gene-2 Promoter Together with c-Myb and Pax-5 in Immature B Cells
Authors: Jin Zhe-Xiong , Kishi Hiroyuki , Wei Xing-Cheng , Matsuda Tadashi , Saito Shigeru , Muraguchi Atsushi
Published: April 2014

The recombination-activating gene (RAG)-1 and RAG-2 are expressed specifically in immature lymphoid cells undergoing the recombination of Ag receptor genes. We studied the regulation of murine RAG-2 promoter and revealed that −41/−17 RAG-2 promoter region, which was indispensable for the RAG-2 promoter activity in B cell lines, contained binding sites for lymphoid enhancer-binding factor-1 (LEF-1), c-Myb, and Pax-5. We showed that these three transcription factors bound the promoter region in vitro and in vivo. Cotransfection assays using a human embryonic kidney cell line (293T) showed that LEF-1, c-Myb, and Pax-5 cooperatively activated the RAG-2 promoter, via their synergistic DNA binding. We also showed that LEF-1, c-Myb, and Pax-5 physically interact in the cells. Finally, we demonstrated that a dominant-negative LEF-1 protein, which lacks the binding site for β-catenin, suppressed the RAG-2 promoter activity as well as the endogenous RAG-2 expression in a pre-B cell line (18.81). These results suggest that LEF-1/β-catenin complex regulates the RAG-2 promoter activation in concert with c-Myb and Pax-5 in immature B cells. The link between LEF-1/β-catenin and Wnt signaling in B lineage cells will be discussed.
Distinct Mechanisms for Cross-Protection of the Upper Versus Lower Respiratory Tract Through Intestinal Priming
Authors: Zuercher Adrian W. , Jiang Han-Qing , Thurnheer M. Christine , Cuff Christopher F. , Cebra John J.
Published: April 2014

A main feature of the common mucosal immune system is that lymphocytes primed in one mucosal inductive site may home to distant mucosal effector sites. However, the mechanisms responsible for such cross-protection remain elusive. To address these we have used a model of local mucosal infection of mice with reovirus. In immunocompetent mice local duodenal priming protected against subsequent respiratory challenge. In the upper respiratory tract this protection appeared to be mainly mediated by specific IgA- and IgG2a-producing B cells, whereas ex vivo active effector memory CTL were found in the lower respiratory tract. In accordance with these findings, clearance of reovirus from the lower respiratory tract, but not from the upper respiratory tract, of infected SCID mice upon transfer of gut-primed lymphocytes depended on the presence of T cells. Taken together this study reveals that intestinal priming leads to protection of both the upper and lower respiratory tracts, however through distinct mechanisms. We suggest that cross-protection in the common mucosal immune system is mediated by trafficking of B cells and effector memory CTL.
Polymorphonuclear Leukocytes from Individuals Carrying the G329A Mutation in the α1,3-Fucosyltransferase VII Gene (FUT7) Roll on E- and P-Selectins
Authors: Bengtson Per , Lundblad Arne , Larson Göran , Påhlsson Peter
Published: April 2014

We recently identified several individuals carrying a missense mutation (G329A; Arg110-Gln) in the FUT7 gene encoding fucosyltransferase VII. This enzyme is involved in the biosynthesis of the sialyl Lewis x (Lex) epitope on human leukocytes, which has been identified as an important component of leukocyte ligands for E- and P-selectin. No enzyme activity was measurable in expression studies in COS-7 cells using the mutated FUT7 construct. One of the identified individuals carried this mutation homozygously. Flow cytometry analysis of polymorphonuclear leukocytes (PMN) from this individual showed a nearly complete absence of staining with mAbs directed against sialyl Lex and a diminished staining with an E-selectin IgG chimera. However, staining with P-selectin IgG chimera and Abs directed against P-selectin glycoprotein ligand-1 was not affected by the mutation. PMN from the homozygously mutated individual was further analyzed in an in vitro flow chamber assay. The number of rolling PMN and the rolling velocities on both E- and P-selectin were in the range of PMN from nonmutated individuals. FUT4 and FUT7 mRNA was quantified in PMN isolated from individuals carrying the FUT7 mutation. It was found that PMN from both FUT7 homozygously and heterozygously mutated individuals exhibited an elevated expression of FUT4 mRNA compared with PMN from FUT7 nonmutated individuals. The elevated expression of fucosyltransferase IV was reflected as an increased expression of the Lex and CD65s Ags on PMN from these individuals. The significance of the mutation was supported by transfection of BJAB cells.
Macrophages, But Not T and B Lymphocytes, Are Critical for Subepidermal Blister Formation in Experimental Bullous Pemphigoid: Macrophage-Mediated Neutrophil Infiltration Depends on Mast Cell Activation
Authors: Chen Ruoyan , Fairley Janet A. , Zhao Ming-Lang , Giudice George J. , Zillikens Detlef , Diaz Luis A. , Liu Zhi
Published: April 2014

Bullous pemphigoid (BP) is a subepidermal blistering disease associated with autoantibodies against two hemidesmosomal proteins, BP180 and BP230. Numerous inflammatory cells infiltrate the upper dermis in BP. We have previously shown by passive transfer studies that Abs to the ectodomain of murine BP180 are capable of triggering blisters in mice that closely mimic human BP. Experimental BP depends on complement activation and neutrophil infiltration. In the present study, we investigated the relative contribution of neutrophils, mast cells (MCs), macrophages (Mφ), and lymphocytes and their functional relationship in the immunopathogenesis of this disease model by using mice deficient in these cells. Wild-type, T cell-deficient, and T and B cell-deficient mice injected intradermally with pathogenic anti-murine BP180 IgG exhibited extensive subepidermal blisters. In contrast, mice deficient in neutrophils, MCs, and Mφ were resistant to experimental BP. MCs play a major role in neutrophil recruitment into the dermis. Furthermore, Mφ-mediated neutrophil infiltration depends on MC activation/degranulation.
Mucosal Plasma Cell Repertoire During HIV-1 Infection
Authors: Scamurra Ronald W. , Nelson Douglas B. , Lin Xue Mei , Miller Darren J. , Silverman Gregg J. , Kappel Tim , Thurn Joseph R. , Lorenz Erin , Kulkarni-Narla Anjali , Janoff Edward N.
Published: April 2014

Impaired development of local Ab responses may predispose HIV-1-infected patients to an increased rate, severity, and duration of mucosal infections. We characterized the repertoire of Ig-producing cells in the intestinal effector compartment (the lamina propria) of HIV-1-infected (n = 29) and seronegative control (n = 27) subjects. The density of Ig-producing cells per area was similar in both groups. However, the proportions of IgA-producing cells were lower in both the duodenum and colon from HIV-1-infected patients compared with those of control subjects (p < 0.05), with compensatory increases in IgG-producing cells in the colon and IgM-producing cells in the duodenum. Similarly, among Abs in the lumen the proportions of IgA were also decreased and the proportions of IgG were increased among HIV-1-infected patients. On a molecular level, VH gene repertoire analyses by RT-PCR revealed comparable proportions of the VH3 family among duodenal IgA transcripts (50–53%) from both groups. VH3 expression was decreased only for IgM among patients with advanced HIV-1 disease (n = 6) compared with that of control subjects (n = 8) (48 ± 8 vs 62 ± 13%; p < 0.01). Moreover, the frequencies of individual IgM and IgA VH3 genes were comparable in each group, including rates of putative HIV-1 gp120-binding VH3 genes (V3-23, V3-30, V3-30/3-30.5). We conclude that, despite a decrement in local IgA producing cells, the density and molecular VH repertoire of mucosal plasma cells are relatively intact among patients with HIV-1 infection. These data suggest that HIV-1-infected patients use functional regulatory mechanisms to provide sufficient VH diversity and effective induction and differentiation of mucosal B cells.
Large and Dissimilar Repertoire of Melan-A/MART-1-Specific CTL in Metastatic Lesions and Blood of a Melanoma Patient
Authors: Mandruzzato Susanna , Rossi Elisabetta , Bernardi Fabiola , Tosello Valeria , Macino Beatrice , Basso Giuseppe , Chiarion-Sileni Vanna , Rossi Carlo Riccardo , Montesco Cristina , Zanovello Paola
Published: April 2014

It is widely accepted that the repertoire of Melan-A-specific T cells naturally selected in melanoma patients is diverse and mostly nonoverlapping among different individuals. To date, however, no studies have addressed the TCR profile in different tumor sites and the peripheral blood from the same patient. We compared the TCR usage of Melan-A-specific T cells from different compartments of a single melanoma patient to evaluate possible clonotype expansion or preferential homing over a 4-mo follow-up period. Using HLA-A2 peptide tetramers, CD8+ T cells recognizing the modified Melan-A immunodominant ELAGIGILTV peptide were isolated from four metastatic lesions resected from a single melanoma patient, and their TCR repertoire was studied. A panel of T cell clones was generated by cell cloning of tetramer-positive cells. Analysis of the TCR β-chain V segment and the complementarity-determining region 3 (CDR3) length and sequence revealed a large diversity in the TCR repertoire, with only some of the clones showing a partial conservation in the CDR3. A similar degree of diversity was found by analyzing a number of T cell clones obtained after sorting a Melan-A-specific population derived from PBLs of the same patient after in vitro culture with the immunodominant epitope. Moreover, clonotypes found at one site were not present in another, suggesting the lack of expansion and circulation of one or more clonotypes. Taken together, these results buttress the notion that the CTLs recognizing the immunodominant Ag of Melan-A comprise a high number of different clonotypic TCR, of which only some exhibit common features in the CDR3.
Cutting Edge: Mouse Pellino-2 Modulates IL-1 and Lipopolysaccharide Signaling
Authors: Yu Kang-Yeol , Kwon Hyung-Joo , Norman David A. M. , Vig Eva , Goebl Mark G. , Harrington Maureen A.
Published: April 2014

Pellino is a Drosophila protein originally isolated in a two-hybrid screen for proteins interacting with the serine/threonine kinase, pelle. Although mammalian homologs have been identified in mouse and man, the function of pellino is as yet unknown. In this study, the cloning, expression pattern, and a preliminary characterization of mouse pellino-2 is described. These studies reveal that mouse pellino-2 is expressed during embryogenesis and in a tissue-restricted manner in the adult. IL-1 induces the association of mouse pellino-2 with the mouse pelle-like kinase/IL-1R-associated kinase protein, a mammalian homolog of pelle. Ectopic pellino-2 expression did not result in NF-κB activation. However, ectopic expression of a mouse pellino-2 antisense construct inhibited IL-1 or LPS-induced activation of NF-κB-dependent IL-8 promoter activity. Our data reveal that mouse pellino-2 is a tissue-restricted component of a signaling pathway that couples the mouse pelle-like kinase/IL-1R-associated kinase protein to IL-1- or LPS-dependent signaling.
Cutting Edge: The Differential Involvement of the N-Finger of GATA-3 in Chromatin Remodeling and Transactivation During Th2 Development
Authors: Takemoto Naofumi , Arai Ken-ichi , Miyatake Shoichiro
Published: April 2014

The development of Th subset is accompanied by subset-specific chromatin remodeling of cytokine gene loci. In this study, we show that the C-terminal, but not the N-terminal zinc finger (N-finger) of GATA-3 mediates the association with the IL-4/IL-13 intergenic DNase I hypersensitive site and the induction of an extended DNase I hypersensitivity on the IL-4/IL-13 locus. Consistently, deletion of the transactivation domains or the C-finger, but not the N-finger, abrogated the induction of IL-4 and IL-13 as well as the down-regulation of IFN-γ. In contrast, the N-finger of GATA-3 was indispensable for the binding to the IL-5 promoter and the induction of IL-5. The selective use of the N-finger may underlie the differential roles of GATA-3 in the induction of IL-4, IL-13, and IL-5.
Cutting Edge: A Natural P451L Mutation in the Cytoplasmic Domain Impairs the Function of the Mouse P2X7 Receptor
Authors: Adriouch Sahil , Dox Claudia , Welge Vivienne , Seman Michel , Koch-Nolte Friedrich , Haag Friedrich
Published: April 2014

The P2X7 receptor (P2X7R) is an ATP-gated channel that mediates apoptosis of cells of the immune system. The capacity of P2X7R to form large pores depends on its large cytoplasmic tail, which harbors a putative TNFR-related death domain. Previous transfection studies indicated that mouse P2X7R forms pores much less efficiently than its counterparts from humans and rats. In this study, we demonstrate that an allelic mutation (P451L) in the predicted death domain of P2X7R confers a drastically reduced sensitivity to ATP-induced pore formation in cells from some commonly used strains of mice, i.e., C57BL/6 and DBA/2. In contrast, most other strains of mice, including strains derived from wild mice, carry P451 at this position as do rats and humans. The effects of the P451L mutation resemble those of the E496A mutation in human P2X7R. These P2X7R mutants may provide useful tools to decipher the molecular mechanisms leading to pore formation.
Susceptibility to T Cell-Mediated Injury in Immune Complex Disease Is Linked to Local Activation of Renin-Angiotensin System: The Role of NF-AT Pathway
Authors: Suzuki Yusuke , Gómez-Guerrero Carmen , Shirato Isao , López-Franco Oscar , Hernández-Vargas Purificación , Sanjuán Guillermo , Ruiz-Ortega Marta , Sugaya Takeshi , Okumura Ko , Tomino Yasuhiko , Ra Chisei , Egido Jesús
Published: April 2014

FcR provides a critical link between ligands and effector cells in immune complex diseases. Emerging evidence reveals that angiotensin (Ang)II exerts a wide variety of cellular effects and contributes to the pathogenesis of inflammatory diseases. In anti-glomerular basement membrane Ab-induced glomerulonephritis (GN), we have previously noted that FcR-deficient mice (γ−/−) surviving from lethal initial damage still developed mesangial proliferative GN, which was drastically prevented by an AngII type 1 receptor (AT1) blocker. We further examined the mechanisms by which renin-Ang system (RAS) participates in this immune disease. Using bone marrow chimeras between γ−/− and AT1−/− mice, we found that glomerular injury in γ−/− mice was associated with CD4+ T cell infiltration depending on renal AT1-stimulation. Based on findings in cutaneous delayed-type hypersensitivity, we showed that AngII-activated renal resident cells are responsible for the recruitment of effector T cells. We next examined the chemotactic activity of AngII-stimulated mesangial cells, as potential mechanisms coupling RAS and cellular immunity. Chemotactic activity for T cells and Th1-associated chemokine (IFN-γ-inducible protein-10 and macrophage-inflammatory protein 1α) expression was markedly reduced in mesangial cells from AT1−/− mice. Moreover, this activity was mainly through calcineurin-dependent NF-AT. Although IFN-γ-inducible protein-10 was NF-κB-dependent, macrophage-inflammatory protein 1α was dominantly regulated by NF-AT. Furthermore, AT1-dependent NF-AT activation was observed in injured glomeruli by Southwestern histochemistry. In conclusion, our data indicate that local RAS activation, partly via the local NF-AT pathway, enhances the susceptibility to T cell-mediated injury in anti-glomerular basement membrane Ab-induced GN. This novel mechanism affords a rationale for the use of drugs interfering with RAS in immune renal diseases.
B Cell Positive Selection by Soluble Self-Antigen
Authors: Julien Sylvie , Soulas Pauline , Garaud Jean-Claude , Martin Thierry , Pasquali Jean-Louis
Published: April 2014

It is well established that autoreactive B cells undergo negative selection. This stands in paradox with the high frequency of so-called natural autoreactive B cells producing low affinity polyreactive autoantibodies with recurrent specificities, suggesting that these B cells are selected on the basis of their autoreactivity. We previously described two transgenic mouse lines (with and without IgD) producing a human natural autoantibody (nAAb) that binds ssDNA and human Fcγ. In the absence of human IgG, nAAb-transgenic B cells develop normally. By crossing these mice with animals expressing knockin chimeric IgG with the human Fcγ, we now show that the constitutive expression of chimeric IgG promotes the increase of nAAb-expressing B cells. This positive selection is critically dependent on the presence of IgD, occurs in the spleen, and concerns all mature B cell subsets, with a relative preferential enrichment of marginal zone B cells. These data support the view that soluble self-Ags can result in positive clonal selection.
A Minimal IFN-γ Promoter Confers Th1 Selective Expression
Authors: Soutto Mohammed , Zhang Feng , Enerson Ben , Tong Yingkai , Boothby Mark , Aune Thomas M.
Published: April 2014

Th1 and Th2 cells differentiate from naive precursors to effector cells that produce either IFN-γ or IL-4, respectively. To identify transcriptional paths leading to activation and silencing of the IFN-γ gene, we analyzed transgenic mice that express a reporter gene under the control of the 5′ IFN-γ promoter. We found that as the length of the promoter is increased, −110 to −225 to −565 bp, the activity of the promoter undergoes a transition from Th1 nonselective to Th1 selective. This is due, at least in part, to a T box expressed in T cells-responsive unit within the −565 to −410 region of the IFN-γ promoter. The −225 promoter is silent when compared with the −110 promoter and silencing correlates with Yin Yang 1 binding to the promoter. The p38 mitogen-activated protein kinase signaling pathway, which also regulates IFN-γ gene transcription, regulates the −70- to −44-bp promoter element. Together, the results demonstrate that a minimal IFN-γ promoter contains a T box expressed in T cells responsive unit and is sufficient to confer Th1 selective expression upon a reporter.
Direct Priming and Cross-Priming Contribute Differentially to the Induction of CD8+ CTL Following Exposure to Vaccinia Virus Via Different Routes
Authors: Shen Xuefei , Wong S. B. Justin , Buck Christopher B. , Zhang Jiangwen , Siliciano Robert F.
Published: April 2014

To explore the relative importance of direct presentation vs cross-priming in the induction of CTL responses to viruses and viral vectors, we generated a recombinant vaccinia vector, vUS11, expressing the human CMV (HCMV) protein US11. US11 dislocates most allelic forms of human and murine MHC class I heavy chains from the lumen of the endoplasmic reticulum into the cytosol, where they are degraded by proteasomes. Expression of US11 dramatically decreased the presentation of viral Ag and CTL recognition of infected cells in vitro without significantly reducing total cell surface MHC class I levels. However, because US11 is an endoplasmic reticulum resident membrane protein, it cannot block presentation by non-infected cells that take up Ag through the cross-priming pathway. We show that the expression of US11 strongly inhibits the induction of primary CD8+ CTLs when the infection occurs via the i.p. or i.v. route, demonstrating that direct priming is critical for the induction of CTL responses to viral infections introduced via these routes. This effect is less dramatic following i.m. infection and is minimal after s.c. or intradermal infection. Thus, classic MHC class I Ag presentation and cross-priming contribute differentially to the induction of CD8+ CTLs following exposure to vaccinia virus via different routes.
Signaling Through NK Cell-Associated CD137 Promotes Both Helper Function for CD8+ Cytolytic T Cells and Responsiveness to IL-2 But Not Cytolytic Activity
Authors: Wilcox Ryan A. , Tamada Koji , Strome Scott E. , Chen Lieping
Published: April 2014

NK cells possess both effector and regulatory activities that may be important during the antitumor immune response. In fact, the generation of antitumor immunity by the administration of an agonistic mAb against CD137 is NK cell-dependent. In this study, we report that NK cells could be induced by IL-2 and IL-15 to express CD137 and ligation of CD137-stimulated NK cell proliferation and IFN-γ secretion, but not their cytolytic activity. Importantly, CD137-stimulated NK cells promoted the expansion of activated T cells in vitro, demonstrating immunoregulatory or “helper” activity for CD8+CTL. Furthermore, tumor-specific CTL activity against P815 tumor Ags was abrogated following anti-CD137 treatment in NK-depleted mice. We further demonstrate that CD137-stimulated helper NK cells expressed the high-affinity IL-2R and were hyperresponsive to IL-2. Taken together with previous findings that CD137 is a critical receptor for costimulation of T cells, our findings suggest that CD137 is a stimulatory receptor for NK cells involved in the crosstalk between innate and adaptive immunity.
IL-19 Induces Production of IL-6 and TNF-α and Results in Cell Apoptosis Through TNF-α
Authors: Liao Yuan-Chun , Liang Wei-Guang , Chen Feng-Wei , Hsu Ju-Hui , Yang Jiann-Jou , Chang Ming-Shi
Published: April 2014

IL-10 is an immunosuppressive cytokine in the immune system. It was in clinical trail as an anti-inflammatory therapy for inflammatory bowel disease and various autoimmune diseases such as psoriasis, rheumatoid arthritis, and multiple sclerosis. IL-19 belongs to the IL-10 family, which includes IL-10, IL-19, IL-20, IL-22, melanoma differentiation-associated gene (MDA-7, IL-24), and AK155 (IL-26). Despite a partial homology in their amino acid sequences, they are dissimilar in their biologic functions. Little is known about the biologic function and gene regulation of IL-19. To understand the gene regulation of human IL-19, we identified a human IL-19 genomic clone and analyzed its promoter region. Five fusion genes containing different regions upstream of exon 1 linked to a luciferase reporter gene were expressed in the canine kidney epithelial-like Madin-Darby canine kidney cells. A fusion gene containing 394 bp showed luciferase activity 7- to 8-fold higher than the negative control of the promoterless fusion gene. We also isolated a full-length mouse cDNA clone. Mouse IL-19 shared 71% amino acid identity with human IL-19. Treatment of monocytes with mouse IL-19 induced the production of IL-6 and TNF-α. It also induced mouse monocyte apoptosis and the production of reactive oxygen species. Taken together, our results indicate that mouse IL-19 may play some important roles in inflammatory responses because it up-regulates IL-6 and TNF-α and induces apoptosis.
Synthesis and Surface Expression of Hyaluronan by Dendritic Cells and Its Potential Role in Antigen Presentation
Authors: Mummert Mark E. , Mummert Diana , Edelbaum Dale , Hui Francis , Matsue Hiroyuki , Takashima Akira
Published: April 2014

Hyaluronan (HA) is a large glycosaminoglycan consisting of repeating disaccharide units of glucuronic acid and N-acetylglucosamine. HA is known to act as a filling material of extracellular matrices and as an adhesive substrate for cellular migration. Here we report that dendritic cells (DC) express mRNAs for HA synthases and hyaluronidases, actively synthesize HA, and display HA on their surfaces. Interestingly, HA expression levels on DC were not significantly altered by their maturation states. With respect to physiological function, three specific HA inhibitors, i.e., bovine proteoglycan, a 12-mer HA-binding peptide (GAHWQFNALTVR) termed Pep-1, and an oligomeric Pep-1 formulation, all interfered with DC-induced activation of CD4+ T cells isolated from DO11.10 TCR transgenic mice. For example, Pep-1 oligomer efficiently inhibited DC-dependent cluster formation, IL-2 and IFN-γ production, and proliferation by DO11.10 T cells in vitro without affecting the viabilities of DC or T cells, DC function to uptake exogenous proteins, or DC-T cell conjugate formation at earlier time points. These observations suggest a paracrine mechanism by which DC-associated HA facilitates some of the late changes in T cell activation. Although T cells constitutively expressed mRNAs for HA synthases and hyaluronidases, their surface HA expression became detectable only after activation. Oligomeric Pep-1 and bovine proteoglycan both inhibited mitogen-triggered T cell activation in the absence of DC, suggesting an autocrine mechanism by which HA expressed by T cells assists their own activation processes. Finally, adoptively transferred DO11.10 T cells showed progressive mitosis when stimulated with Ag-pulsed DC in living animals, and this clonal expansion was inhibited significantly by administration of Pep-1 oligomer. Our findings may introduce a new concept that relatively simple carbohydrate moieties expressed on DC and perhaps T cells play an important immunomodulatory role during Ag presentation.
Activated STAT4 Has an Essential Role in Th1 Differentiation and Proliferation That Is Independent of Its Role in the Maintenance of IL-12Rβ2 Chain Expression and Signaling
Authors: Nishikomori Ryuta , Usui Takashi , Wu Chang-Yu , Morinobu Akio , O’Shea John J. , Strober Warren
Published: April 2014

In this study we demonstrated that CD4+ T cells from STAT4−/− mice exhibit reduced IL-12R expression and poor IL-12R signaling function. This raised the question of whether activated STAT4 participates in Th1 cell development mainly through its effects on IL-12 signaling. In a first approach to this question we determined the capacity of CD4+ T cells from STAT4−/− bearing an IL-12Rβ2 chain transgene (and thus capable of normal IL-12R expression and signaling) to undergo Th1 differentiation when stimulated by Con A and APCs. We found that such cells were still unable to exhibit IL-12-mediated IFN-γ production. In a second approach to this question, we created Th2 cell lines (D10 cells) transfected with STAT4-expressing plasmids with various tyrosine→phenylalanine mutations and CD4+ T cell lines from IL-12β2−/− mice infected with retroviruses expressing similarly STAT4 mutations that nevertheless express surface IL-12Rβ2 chains. We then showed that constructs that were unable to support STAT4 tyrosine phosphorylation (in D10 cells) as a result of mutation were also incapable of supporting IL-12-induced IFN-γ production (in IL-12Rβ2−/− cells). Thus, by two complementary approaches we demonstrated that activated STAT4 has an essential downstream role in Th1 cell differentiation that is independent of its role in the support of IL-12Rβ2 chain signaling. This implies that STAT4 is an essential element in the early events of Th1 differentiation.
Coxiella burnetiiSurvival in THP-1 Monocytes Involves the Impairment of Phagosome Maturation: IFN-γ Mediates its Restoration and Bacterial Killing
Authors: Ghigo Eric , Capo Christian , Tung Ching-Hsuan , Raoult Didier , Gorvel Jean-Pierre , Mege Jean-Louis
Published: April 2014

The subversion of microbicidal functions of macrophages by intracellular pathogens is critical for their survival and pathogenicity. The replication of Coxiella burnetii, the agent of Q fever, in acidic phagolysosomes of nonphagocytic cells has been considered as a paradigm of intracellular life of bacteria. We show in this study that C. burnetii survival in THP-1 monocytes was not related to phagosomal pH because bacterial vacuoles were acidic independently of C. burnetii virulence. In contrast, virulent C. burnetii escapes killing in resting THP-1 cells by preventing phagosome maturation. Indeed, C. burnetii vacuoles did not fuse with lysosomes because they were devoid of cathepsin D, and did not accumulate lysosomal trackers; the acquisition of markers of late endosomes and late endosomes-early lysosomes was conserved. In contrast, avirulent variants of C. burnetii were eliminated by monocytes and their vacuoles accumulated late endosomal and lysosomal markers. The fate of virulent C. burnetii in THP-1 monocytes depends on cell activation. Monocyte activation by IFN-γ restored C. burnetii killing and phagosome maturation as assessed by colocalization of C. burnetii with active cathepsin D. In addition, when IFN-γ was added before cell infection, it was able to stimulate C. burnetii killing but it also induced vacuolar alkalinization. These findings suggest that IFN-γ mediates C. burnetii killing via two distinct mechanisms, phagosome maturation, and phagosome alkalinization. Thus, the tuning of vacuole biogenesis is likely a key part of C. burnetii survival and the pathophysiology of Q fever.
Morphologic Detection and Functional Assessment of Reconstituted Normal Alveolar Macrophages in the Lungs of SCID Mice
Authors: Pasula Rajamouli , Weaver Todd , Martinez Manuel A. , Martin William J.
Published: April 2014

Alveolar macrophages (AMs) from immunocompetent animals were isolated from bronchoalveolar lavage and labeled with the fluorescent marker 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI). These AMs were administered intratracheally into mechanically ventilated SCID mice. From 1 to 28 days later, the recipient mice underwent bronchoalveolar lavage to isolate their AMs. To determine whether reconstituted AMs were still immunocompetent, the recovered AMs were assayed for their ability to phagocytose fluorescein-labeled zymosan-coated beads. After incubation with the beads, samples were assayed using a fluorescent-activated cell sorter to identify DiI-labeled reconstituted AMs, unlabeled resident AMs, and the proportion of these two groups undergoing phagocytosis. DiI-labeled AMs accounted for ∼50% of all returned AMs. Additionally, the reconstituted AMs from normal BALB/c mice retained phagocytic activity compared with AMs from immunodeficient SCID mice. Reconstituted AMs demonstrated enhanced phagocytic activity compared with resident SCID AMs for up to 28 days following reconstitution. These results indicate that immunocompetent AMs can be successfully reconstituted into an immunodeficient host to partially restore alveolar host defense.
Activation of Human Oral Epithelial Cells by Neutrophil Proteinase 3 Through Protease-Activated Receptor-2
Authors: Uehara Akiko , Sugawara Shunji , Muramoto Koji , Takada Haruhiko
Published: April 2014

Proteinase 3 (PR3), a 29-kDa serine proteinase secreted from activated neutrophils, also exists in a membrane-bound form, and is suggested to actively contribute to inflammatory processes. The present study focused on the mechanism by which PR3 activates human oral epithelial cells. PR3 activated the epithelial cells in culture to produce IL-8 and monocyte chemoattractant protein-1 and to express ICAM-1 in a dose- and time-dependent manner. Incubation of the epithelial cells for 24 h with PR3 resulted in a significant increase in the adhesion to neutrophils, which was reduced to baseline levels in the presence of anti-ICAM-1 mAb. Activation of the epithelial cells by PR3 was inhibited by serine proteinase inhibitors and serum. The epithelial cells strongly express protease-activated receptor (PAR)-1 and PAR-2 mRNA and weakly express PAR-3 mRNA. The expression of PAR-2 on the cell surface was promoted by PR3, and inhibited by cytochalasin B, but not by cycloheximide. PR3 cleaved the peptide corresponding to the N terminus of PAR-2 with exposure of its tethered ligand. Treatment with trypsin, an agonist for PAR-2, and a synthetic PAR-2 agonist peptide induced intracellular Ca2+ mobilization, and rendered cells refractory to subsequent stimulation with PR3 and vice versa. The production of cytokine induced by PR3 and the PAR-2 agonist peptide was completely abolished by a phospholipase C inhibitor. These findings suggest that neutrophil PR3 activates oral epithelial cells through G protein-coupled PAR-2 and actively participates in the process of inflammation such as periodontitis.
Clonal Deletion of Simian Virus 40 Large T Antigen-Specific T Cells in the Transgenic Adenocarcinoma of Mouse Prostate Mice: An Important Role for Clonal Deletion in Shaping the Repertoire of T Cells Specific for Antigens Overexpressed in Solid Tumors
Authors: Zheng Xincheng , Gao Jian-Xin , Zhang Huiming , Geiger Terrence L. , Liu Yang , Zheng Pan
Published: April 2014

In addition to their overexpression in cancer cells, most of the tumor-associated Ags are expressed at low but detectable levels in normal tissues. It is not clear whether the repertoire of T cells specific for unmutated tumor Ags is shaped by negative selection during T cell development. The transgenic adenocarcinoma of mouse prostate (TRAMP) model is transgenic for the SV40 large T Ag (Tag) under the control of the rat probasin regulatory elements. Although it has been established that T lymphocytes from TRAMP mice are tolerant to SV40 Tag, the mechanism of the tolerance is largely unknown. To examine whether the T cell clonal deletion is responsible for the tolerance, we crossed the TRAMP mice with mice transgenic for a rearranged TCR specific for SV40 Tag presented by the H-2Kk. Double transgenic TRAMP/TCR mice showed profound thymic deletion of SV40 Tag-reactive T cells, including a 6- to 10-fold reduction in the total thymocyte numbers and a >50-fold reduction in phenotypically mature T cells. Consistent with this finding, we observed that the SV40 Tag and endogenous mouse probasin genes are expressed at low levels in the thymus. These results demonstrate that clonal deletion is a major mechanism for tolerance to Ags previously regarded as prostate-specific, and provide direct evidence that the T cell repertoire specific for an unmutated tumor Ag can be shaped by clonal deletion in the thymus.
Caspase-Independent Phosphatidylserine Exposure During Apoptosis of Primary T Lymphocytes
Authors: Ferraro-Peyret Carole , Quemeneur Laurence , Flacher Monique , Revillard Jean-Pierre , Genestier Laurent
Published: April 2014

Exposure of phosphatidylserine (PS) on the outer leaflet of the plasma membrane is a key feature of apoptosis. As the signals underlying these phenomena are unknown, it is generally assumed that PS exposure is a consequence of caspase activation, another hallmark of apoptosis. In this study we investigated the role of caspases in PS externalization during apoptosis of activated PBL triggered by drugs (etoposide, staurosporine), CD95 engagement, or IL-2 withdrawal. Anti-CD95 mAb induces a rapid activation of caspases, followed by PS exposure and mitochondrial transmembrane potential (ΔΨm) disruption. In contrast, etoposide (ETO), staurosporine (STS), or IL-2 withdrawal triggers concomitant caspase activation, PS exposure, and ΔΨm disruption. Such kinetics suggest that PS exposure could be independent of caspase activation. As expected, in activated PBL treated by anti-CD95 mAb, the pan-caspase inhibitor Cbz-Val-Ala-Asp(OMe)-fluoromethylketone and the caspase-8 inhibitor Cbz-Leu-Glu-Thr-Asp(OMe)-fluoromethylketone, but not the caspase-9 inhibitor Cbz-Leu-Glu-His-Asp(OMe)-fluoromethylketone, inhibit PS externalization and ΔΨm disruption. Surprisingly, during apoptosis induced by ETO, STS, or IL-2 withdrawal, none of those caspase inhibitors prevents PS externalization or ΔΨm disruption, whereas they all inhibit DNA fragmentation as well as the morphological features of nuclear apoptosis. In Jurkat and H9 T cell lines, as opposed to activated PBL, PS exposure is inhibited by Cbz-Val-Ala-Asp(OMe)-fluoromethylketone during apoptosis induced by CD95 engagement, ETO, or STS. Thus, caspase-independent PS exposure occurs in primary T cells during apoptosis induced by stimuli that do not trigger death receptors.