bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential Expression and Regulation of Toll-Like Receptors (TLR) in Human Leukocytes: Selective Expression of TLR3 in Dendritic Cells
Authors: Muzio Marta , Bosisio Daniela , Polentarutti Nadia , D’amico Giovanna , Stoppacciaro Antonella , Mancinelli Roberta , van’t Veer Cornelis , Penton-Rol Giselle , Ruco Luigi P. , Allavena Paola , Mantovani Alberto 
Published: April 2014

AbstractMembers of the Toll-like receptor (TLR) family probably play a fundamental role in pathogen recognition and activation of innate immunity. The present study used a systematic approach to analyze how different human leukocyte populations express specific transcripts for the first five characterized TLR family members. TLR1 was expressed in all leukocytes examined, including monocytes, polymorphonuclear leukocytes, T and B cells, and NK cells. In contrast TLR2, TLR4, and TLR5 were expressed in myelomonocytic elements. Exposure to bacterial products, such as LPS or lipoarabinomannan, or to proinflammatory cytokines increased TLR4 expression in monocytes and polymorphonuclear leukocytes, whereas IL-10 blocked this effect. TLR3 was only expressed in human dendritic cells (DC) wherein maturation induced by bacterial products or cytokines was associated with reduced expression. TLR3 mRNA expression was detected by in situ hybridization in DC and lymph nodes. These results demonstrate that TLR1 through TLR5 mRNAs are differentially expressed and regulated in human leukocytes. In particular, expression of TLR3 transcripts is restricted to DC that are the only elements which express the full TLR repertoire. These data suggest that TLR can be classified based on expression pattern as ubiquitous (TLR1), restricted (TLR2, TLR4, and TLR5 in myelomonocytic cells), and specific (TLR3 in DC) molecules.
Simian Immunodeficiency Virus (SIV)-Specific CTL Are Present in Large Numbers in Livers of SIV-Infected Rhesus Monkeys
Authors: Schmitz Jörn E. , Kuroda Marcelo J. , Veazey Ronald S. , Seth Aruna , Taylor Wesley M. , Nickerson Christine E. , Lifton Michelle A. , Dailey Peter J. , Forman Meryl A. , Racz Paul , Tenner-Racz Klara , Letvin Norman L. 
Published: April 2014

AbstractThe immunopathogenesis of AIDS-associated hepatitis was explored in the SIV/rhesus monkey model. The livers of SIV-infected monkeys showed a mild hepatitis, with a predominantly CD8+ T lymphocyte infiltration in the periportal fields and sinusoids. These liver-associated CD8+ T cells were comprised of a high percentage of SIV-specific CTL as defined by MHC class I/Gag peptide tetramer binding and Gag peptide epitope-specific lytic activity. There was insufficient viral replication in these livers to account for attracting this large number of functional virus-specific CTL to the liver. There was also no evidence that the predominant population of CTL were functionally end-stage cells trapped in the liver and destined to undergo apoptotic cell death in that organ. Interestingly, we noted that liver tetramer-binding cells showed an increased expression of CD62L, an adhesion molecule usually only rarely expressed on tetramer-binding cells. This observation suggests that the expression of specific adhesion molecules by CTL might facilitate the capture of these cells in the liver. These results demonstrate that functional SIV-specific CD8+ T cells are present in large numbers in the liver of chronically SIV-infected monkeys. Thus, the liver may be a trap for virus-specific cytotoxic T cells.
Novel Protein Transfection of Primary Rat Cortical Neurons Using an Antibody That Penetrates Living Cells
Authors: Weisbart Richard H. , Baldwin Roger , Huh Brian , Zack Debra Jeske , Nishimura Robert 
Published: April 2014

AbstractAn Ab-based system to deliver functional proteins into neurons was developed using the murine mAb, mAb 3E10. This was achieved by covalently conjugating catalase to the Ab so that the conjugate retained high activity for the degradation of hydrogen peroxide. Three-dimensional fluorescence microscopy was used to demonstrate penetration of the Ab into the nucleus of living primary cortical neurons. The Ab conjugate localized in both the cytoplasm and nucleus. Retention of catalase activity after penetration and distribution of conjugate was demonstrated by reduction in cell death following exposure of treated neurons to hydrogen peroxide. These studies illustrate the potential of this method for the intracellular delivery of therapeutic proteins.
Costimulation by B7-1 and B7-2 Is Required for Autoimmune Disease in MRL-FaslprMice
Authors: Kinoshita Koji , Tesch Greg , Schwarting Andreas , Maron Ruth , Sharpe Arlene H. , Kelley Vicki Rubin 
Published: April 2014

AbstractAutoimmune lupus nephritis is dependent on infiltrating autoreactive leukocytes and Igs. B7 costimulatory molecules (B7-1 and B7-2) provide signals essential for T cell activation and Ig class switching. In MRL-Faslpr mice, a model of human lupus, although multiple tissues are targeted for autoimmune injury, nephritis is fatal. We identified intrarenal B7-1 and B7-2 expression, restricted to kidney-infiltrating leukocytes, before and increasing with progressive nephritis in MRL-Faslpr mice. Thus, we hypothesized that the B7 pathway is required for autoimmune disease in MRL-Faslpr mice. To investigate the role of B7 costimulatory molecules in this autoimmune disease, we generated a MRL-Faslpr strain deficient in B7-1 and B7-2. Strikingly, MRL-Faslpr mice lacking both B7 costimulators do not develop kidney (glomerular, tubular, interstitial, vascular) pathology, or proteinuria, and survive far longer. Intrarenal downstream effector transcripts (IFN-γ, IL-12, monocyte chemoattractant protein-1, CSF-1) linked to nephritis remained at normal levels compared with wild-type mice. Skin lesions and lymphoid enlargement characteristic of MRL-Faslpr mice were diminished in B7-1/B7-2-deficient MRL-Faslpr mice. B7-1/B7-2-deficient MRL-Faslpr mice did not develop leukocytic infiltrates, elevated serum IgG and isotypes (G1,G2b,G3), autoantibodies, and intrarenal IgG deposits. Our findings demonstrate that B7-1 and B7-2 costimulatory pathways are critical to the pathogenesis of autoimmune lupus.
Exceptional Resistance of Human H2 Glioblastoma Cells to Complement-Mediated Killing by Expression and Utilization of Factor H and Factor H-Like Protein 1
Authors: Junnikkala S. , Jokiranta T. S. , Friese M. A. , Jarva H. , Zipfel P. F. , Meri S. 
Published: April 2014

AbstractOf over 20 nucleated cell lines we have examined to date, human H2 glioblastoma cells have turned out to be the most resistant to complement-mediated cytolysis in vitro. H2 cells expressed strongly the membrane attack complex inhibitor protectin (CD59), moderately CD46 (membrane cofactor protein) and CD55 (decay-accelerating factor), but no CD35 (complement receptor 1). When treated with a polyclonal anti-H2 Ab, anti-CD59 mAb, and normal human serum, only 5% of H2 cells became killed. Under the same conditions, 70% of endothelial-like EA.hy 926 cells and 40% of U251 control glioma cells were killed. A combined neutralization of CD46, CD55, and CD59 increased H2 lysis only minimally, demonstrating that these complement regulators are not enough to account for the resistance of H2 cells. After treatment with Abs and serum, less C5b-9 was deposited on H2 than on U251 and EA.hy 926 cell lines. A reason for the exceptional resistance of H2 cells was revealed when RT-PCR and protein biochemical methods showed that the H2 cells, unlike the other cell lines tested, actively produced the soluble complement inhibitors factor H and factor H-like protein 1. H2 cells were also capable of binding human factor H from the fluid phase to their cell surface and promoted the cleavage of C3b to its inactive form iC3b more efficiently than U251 and EA.hy 926 cells. In accordance, anti-factor H mAbs enhanced killing of H2 glioblastoma cells. Taken together, our results show that production and binding of factor H and factor H-like protein 1 is a novel mechanism that these malignant cells utilize to escape complement-mediated killing.
Altered Composition of the Immunological Synapse in an Anergic, Age-Dependent Memory T Cell Subset
Authors: Eisenbraun Michael D. , Tamir Ami , Miller Richard A. 
Published: April 2014

AbstractIn young mice, memory CD4 T lymphocytes with high P-glycoprotein activity (P-gphigh) are unresponsive to TCR stimulation in vitro but can be activated by PMA plus ionomycin. The proportion of these hyporesponsive cells increases considerably with age. The earliest events in T cell activation were studied in P-gphigh and P-gplow CD4 memory cells at the single-cell level using confocal immunofluorescence methods. Recruitment of both linker for activation of T cells (LAT) and protein kinase C-θ to the immunological synapse, i.e., the site of T cell interaction with stimulator cells, was greatly impaired in P-gphigh cells from both young and old mice. Translocation of NF-AT to the nucleus, CD69 expression, and proliferative capacity were also diminished to a similar extent in P-gphigh cells under the same activation conditions. In contrast, movement of c-Cbl to the synapse region occurred in a high proportion of CD4 memory T cells regardless of P-gp subset or age. Moreover, although P-gplow cells frequently recruited both c-Cbl and LAT to the APC synapse, cells in the less responsive P-gphigh subset frequently relocated c-Cbl, but not LAT, to the interface region. In some systems, c-Cbl can act as a negative regulator of receptor-dependent tyrosine kinases, and alterations of c-Cbl to LAT ratios in the P-gphigh subset may thus contribute to the hyporesponsiveness of this age-dependent, anergic memory cell population.
Immunodominance Among EBV-Derived Epitopes Restricted by HLA-B27 Does Not Correlate with Epitope Abundance in EBV-Transformed B-Lymphoblastoid Cell Lines
Authors: Crotzer Victoria L. , Christian Robert E. , Brooks Jill M. , Shabanowitz Jeffrey , Settlage Robert E. , Marto Jarrod A. , White Forest M. , Rickinson Alan B. , Hunt Donald F. , Engelhard Victor H. 
Published: April 2014

Abstract
Using synthetic peptides, the HLA-B27-restricted CTL response to EBV in asymptomatic virus carriers has been mapped to four epitope regions in EBV latent cycle Ags. One of these peptide-defined epitopes (RRIYDLIEL) tends to be immunodominant and is recognized in the context of all three B27 subtypes studied, B*2702, B*2704, and B*2705. The other peptide-defined epitopes induce responses only in the context of one subtype, the immunogenic combinations being RRARSLSAERY/B*2702, RRRWRRLTV/B*2704, and FRKAQIQGL/B*2705. We used immunoaffinity chromatography to isolate the naturally presented viral peptides associated with these MHC class I molecules on the surface of EBV-transformed B-LCL. Using CTL reconstitution assays in conjunction with mass spectrometry, we established that the naturally processed and presented peptides are identical with the previously identified synthetic sequences. Despite the subtype-specific immunogenicity of three of the four epitopes, all four epitope peptides were found in association with each of the three different HLA-B27 subtypes. Indeed, those peptides that failed to induce a response in the context of a particular HLA-B27 subtype were frequently presented at greater abundance by that subtype than were the immunogenic peptides. Furthermore, among the peptides that did induce a response, immunodominance did not correlate with epitope abundance; in fact the immunodominant RRIYDLIEL epitope was least abundant, being present at less than one copy per cell. The relationship of this unexpected finding to the persistence of EBV is discussed.
Inhibition of Human NK Cell-Mediated Killing by CD1 Molecules
Authors: Carbone Ennio , Terrazzano Giuseppe , Melián Augustin , Zanzi Delia , Moretta Lorenzo , Porcelli Steven , Kärre Klas , Zappacosta Serafino 
Published: April 2014

Abstract
It is now well established that NK cells recognize classical and nonclassical MHC class I molecules and that such recognition typically results in the inhibition of target cell lysis. Given the known structural similarities between MHC class I and non-MHC-encoded CD1 molecules, we investigated the possibility that human CD1a, -b, and -c proteins might also function as specific target structures for NK cell receptors. Here we report that expression of CD1a, -b, or -c can partially inhibits target cell lysis by freshly isolated human NK cells and cultured NK lines. The inhibitory effects of CD1 molecules on NK cell could be shown upon expression of individual CD1 proteins in transfected NK-sensitive target cells, and these effects could be reversed by incubation of the target cells with mAbs specific for the expressed form of CD1. Inhibitory effects of CD1 expression on NK-mediated lysis could also be shown for cultured human dendritic cells, which represent a cell type that prominently expresses the various CD1 proteins in vivo. In addition, the bacterial glycolipid Ags known to be bound and presented by CD1 proteins could significantly augment the observed inhibitory effects on target cell lysis by NK cells.
The Selective Proteasome Inhibitors Lactacystin and Epoxomicin Can Be Used to Either Up- or Down-Regulate Antigen Presentation at Nontoxic Doses
Authors: Schwarz Katrin , de Giuli Rita , Schmidtke Gunter , Kostka Susanne , van den Broek Maries , Kim Kyung Bo , Crews Craig M. , Kraft Regine , Groettrup Marcus 
Published: April 2014

AbstractThe complete inhibition of proteasome activities interferes with the production of most MHC class I peptide ligands as well as with cellular proliferation and survival. In this study we have investigated how partial and selective inhibition of the chymotrypsin-like activity of the proteasome by the proteasome inhibitors lactacystin or epoxomicin would affect Ag presentation. At 0.5–1 μM lactacystin, the presentation of the lymphocytic choriomeningitis virus-derived epitopes NP118 and GP33 and the mouse CMV epitope pp89–168 were reduced and were further diminished in a dose-dependent manner with increasing concentrations. Presentation of the lymphocytic choriomeningitis virus-derived epitope GP276, in contrast, was markedly enhanced at low, but abrogated at higher, concentrations of either lactacystin or epoxomicin. The inhibitor-mediated effects were thus epitope specific and did not correlate with the degradation rates of the involved viral proteins. Although neither apoptosis induction nor interference with cellular proliferation was observed at 0.5–1 μM lactacystin in vivo, this concentration was sufficient to alter the fragmentation of polypeptides by the 20S proteasome in vitro. Our results indicate that partial and selective inhibition of proteasome activity in vivo is a valid approach to modulate Ag presentation, with potential applications for the treatment of autoimmune diseases and the prevention of transplant rejection.
M-1/M-2 Macrophages and the Th1/Th2 Paradigm
Authors: Mills Charles D. , Kincaid Kristi , Alt Jennifer M. , Heilman Michelle J. , Hill Annette M. 
Published: April 2014

AbstractEvidence is provided that macrophages can make M-1 or M-2 responses. The concept of M-1/M-2 fomented from observations that macrophages from prototypical Th1 strains (C57BL/6, B10D2) are more easily activated to produce NO with either IFN-γ or LPS than macrophages from Th2 strains (BALB/c, DBA/2). In marked contrast, LPS stimulates Th2, but not Th1, macrophages to increase arginine metabolism to ornithine. Thus, M-1/M-2 does not simply describe activated or unactivated macrophages, but cells expressing distinct metabolic programs. Because NO inhibits cell division, while ornithine can stimulate cell division (via polyamines), these results also indicate that M-1 and M-2 responses can influence inflammatory reactions in opposite ways. Macrophage TGF-β1, which inhibits inducible NO synthase and stimulates arginase, appears to play an important role in regulating the balance between M-1 and M-2. M-1/M-2 phenotypes are independent of T or B lymphocytes because C57BL/6 and BALB/c NUDE or SCID macrophages also exhibit M-1/M-2. Indeed, M-1/M-2 proclivities are magnified in NUDE and SCID mice. Finally, C57BL/6 SCID macrophages cause CB6F1 lymphocytes to increase IFN-γ production, while BALB/c SCID macrophages increase TGF-β production. Together, the results indicate that M-1- or M-2-dominant macrophage responses can influence whether Th1/Th2 or other types of inflammatory responses occur.
TNF-α-Induced Secretion of C-C Chemokines Modulates C-C Chemokine Receptor 5 Expression on Peripheral Blood Lymphocytes
Authors: Hornung Felicita , Scala Giuseppe , Lenardo Michael J. 
Published: April 2014

AbstractPeripheral blood lymphocytes express CCR5, a chemokine receptor for immune cell migration and calcium signaling that serves as an important coreceptor for the HIV. After in vitro stimulation, CCR5 expression is dramatically increased on mature T lymphocytes, especially on the CD45RO+ memory subset. In this study, we report that TNF-α delays the surface expression of CCR5 on PBLs after activation and diminishes CCR5 irrespective of its initial level. Functional loss of CCR5 is reflected in a decreased capability of the treated cells to migrate and signal calcium after MIP-1β stimulation. The effect is mediated via the p80 type II TNF receptor (TNFR2), which induces NF-κB among other factors, leading to an enhanced secretion of the chemokines macrophage-inflammatory protein-1α, macrophage-inflammatory protein-1β, and RANTES. Expression of these chemokines directly down-regulates CCR5. These findings reveal a new regulatory mechanism utilized by activated peripheral T cells to modulate their chemotaxis and potentially other functions mediated by CCR5, including the infection of T lymphocytes by macrophage-tropic HIV strains.
Gender-Dependent IL-12 Secretion by APC Is Regulated by IL-10
Authors: Wilcoxen Scott C. , Kirkman Erlinda , Dowdell Kennichi C. , Stohlman Stephen A. 
Published: April 2014

AbstractFemale SJL mice preferentially mount Th1-immune responses and are susceptible to the active induction of experimental allergic encephalomyelitis. By contrast, young adult male SJL are resistant to experimental allergic encephalomyelitis due to an APC-dependent induction of Th2 cells. The basis for this gender-dependent differential T cell induction was examined by analysis of macrophage APC cytokine secretion during T cell activation. APC derived from females secrete IL-12, but not IL-10, during T cell activation. By contrast, APC derived from males secrete IL-10, but not IL-12, during T cell activation. Activation of T cells with APC derived from the opposite sex demonstrated that these cytokines were derived from the respective APC populations. Furthermore, inhibition of IL-10, but not TGF-β, during T cell activation resulted in the secretion of IL-12 by male-derived APC. APC from naive male mice, in which IL-10 was reduced in vivo before isolation, also secrete IL-12, demonstrating altered APC cytokine secretion was due to an environment high in IL-10 before Ag encounter. Finally, APC derived from castrated male mice preferentially secrete IL-12 during T cell activation. These data demonstrate a link between gonadal hormones and APC activity and suggest that these hormones alter the APC, thereby influencing cytokine secretion during initial T cell activation.
Correlation of T Cell Independence of Antibody Responses with Antigen Dose Reaching Secondary Lymphoid Organs: Implications for Splenectomized Patients and Vaccine Design
Authors: Ochsenbein Adrian F. , Pinschewer Daniel D. , Odermatt Bernhard , Ciurea Adrian , Hengartner Hans , Zinkernagel Rolf M. 
Published: April 2014

AbstractMany natural viral and bacterial pathogens activate B cells independently of Th cells (TI Ags). This study analyzed the characteristics of the activation of B cells after immunization with various forms of viral Ags using different immunization routes and found a decreasing dependence on T help with increasing amounts of Ag recruited to the spleen. Repetitive antigenic structure facilitated TI B cell responses if Ag was present in lymphoid organs. These results suggest that 1) Ag dose and localization in secondary lymphoid organs are the key for B cell activation in the absence of T help; 2) early TI Ab responses are crucial to protect against systemically spreading acute cytopathic infectious agents; and 3) there may be new rationales for improved vaccine design.
The Murine Chemokine CXCL11 (IFN-Inducible T Cell α Chemoattractant) Is an IFN-γ- and Lipopolysaccharide- Inducible Glucocorticoid-Attenuated Response Gene Expressed in Lung and Other Tissues During Endotoxemia
Authors: Widney Daniel P. , Xia Yu-Rong , Lusis Aldons J. , Smith Jeffrey B. 
Published: April 2014

AbstractA new murine chemokine was identified in a search for glucocorticoid-attenuated response genes induced in the lung during endotoxemia. The first 73 residues of the predicted mature peptide are 71% identical and 93% similar to human CXCL11/IFN-inducible T cell α chemoattractant (I-TAC) (alias β-R1, H174, IFN-inducible protein 9 (IP-9), and SCYB9B). The murine chemokine has six additional residues at the carboxyl terminus not present in human I-TAC. Identification of this cDNA as murine CXCL11/I-TAC is supported by phylogenetic analysis and by radiation hybrid mapping of murine I-TAC (gene symbol Scyb11) to mouse chromosome 5 close to the genes for monokine induced by IFN-γ (MIG) and IP10. Murine I-TAC mRNA is induced in RAW 264.7 macrophages by IFN-γ or LPS and is weakly induced by IFN-αβ. IFN-γ induction of murine I-TAC is markedly enhanced by costimulation with LPS or IL-1β in RAW cells and by TNF-α in both RAW cells and Swiss 3T3 fibroblasts. Murine I-TAC is induced in multiple tissues during endoxemia, with strongest expression in lung, heart, small intestine, and kidney, a pattern of tissue expression different from those of MIG and IP10. Peak expression of I-TAC message is delayed compared with IP10, both in lung after i.v. LPS and in RAW 264.7 cells treated with LPS or with IFN-γ. Pretreatment with dexamethasone strongly attenuates both IFN-γ-induced I-TAC expression in RAW cells and endotoxemia-induced I-TAC expression in lung and small intestine. The structural and regulatory similarities of murine and human I-TAC suggest that mouse models will be useful for investigating the role of this chemokine in human biology and disease.
Modulation of HLA-G Antigens Expression by Human Cytomegalovirus: Specific Induction in Activated Macrophages Harboring Human Cytomegalovirus Infection
Authors: Onno Myriam , Pangault Céline , Le Friec Gaëlle , Guilloux Valérie , André Patrice , Fauchet Renée 
Published: April 2014

Abstract
After infection, human CMV (HCMV) establishes a latent and persistent infection in immature myeloid progenitors and peripheral blood monocytes. Completion of the HCMV life cycle is possible upon maturation of monocytes to tissue macrophages and under permissive circumstances, e.g., immunosuppression. We investigated the hypothesis that HLA-G molecules could be induced during HCMV reactivation in activated macrophages to favor virus dissemination. In this study, we provide evidence that HLA-G Ags are produced during viral reactivation in macrophages generated after allogeneic stimulation of HCMV latently infected monocytes. While HLA-G surface expression is up-regulated, classical MHC-I molecules are partially down-regulated by HCMV. In vivo, bronchoalveolar macrophages collected from patients suffering from acute HCMV pneumonitis also express HLA-G molecules. The direct correlation between HLA-G Ag induction and HCMV infection was confirmed in U-373 MG astrocytoma cells. Soluble HLA-G expression is stimulated upon HCMV infection, and this modulation depends on the cooperative action of the two immediate-early-1 pp72 and immediate-early-2 pp86 products. Because HLA-G transcription is active in macrophages and U-373 MG astrocytoma cells, it is likely that the modulation of HLA-G protein expression during HCMV replication occurs at a post-transcriptional level. Our data suggest that induction of HLA-G molecules could be an additional mechanism that helps HCMV to subvert host defenses.