bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biosynthesis and Posttranslational Regulation of Human IL-12
Authors: Carra Giuseppe , Gerosa Franca , Trinchieri Giorgio 
Published: April 2014

AbstractIL-12 is a heterodimeric proinflammatory cytokine consisting of a light α-chain, formerly defined as p35, disulfide-linked to a heavier β-chain, formerly defined as p40. The β-chain is also produced in large excess in a free form, and disulfide-linked β-chain homodimers with anti-inflammatory effects are produced in the mouse. We analyzed the biosynthesis and glycosylation of IL-12 in human monocytes, and in a cell line stably transfected with IL-12 α and β genes (P5-0.1). The IL-12 heterodimer and free β-chain were immunoprecipitated from supernatants and cell lysates of metabolically labeled cells and resolved in SDS-PAGE. Whereas the β-chain showed similar pI pattern whether in the free form or associated in the heterodimer, either in the secreted or intracellular form, the α-chain in the secreted heterodimer was much more acidic than that present in the intracellular heterodimer. Deglycosylation experiments with neuraminidase and Endo-F combined with two-dimensional PAGE of single bands of the intracellular vs extracellular IL-12 heterodimer revealed that the α-chain was extensively modified with sialic acid adducts to N-linked oligosaccharides before secretion. N-glycosylation inhibition by tunicamycin (TM) did not alter free β-chain secretion, while preventing the IL-12 heterodimer assembling and secretion. Pulse-chase experiments indicated that IL-12 persists intracellularly for a long period as an immature heterodimer, and that glycosylation is the regulatory step that determines its secretion. β-chain disulfide-linked homodimers were observed in TM-treated P5-0.1 cells, but in neither TM-treated nor untreated monocytes.
Requirement of Endogenous Stem Cell Factor and Granulocyte-Colony-Stimulating Factor for IL-17-Mediated Granulopoiesis
Authors: Schwarzenberger Paul , Huang Weitao , Ye Peng , Oliver Peter , Manuel Misty , Zhang Zili , Bagby Gregory , Nelson Steve , Kolls Jay K. 
Published: April 2014

AbstractIL-17 is a novel, CD4+ T cell-restricted cytokine. In vivo, it stimulates hematopoiesis and causes neutrophilia consisting of mature granulocytes. In this study, we show that IL-17-mediated granulopoiesis requires G-CSF release and the presence or induction of the transmembrane form of stem cell factor (SCF) for optimal granulopoiesis. However, IL-17 also protects mice from G-CSF neutralization-induced neutropenia. G-CSF neutralization completely reversed IL-17-induced BM progenitor expansion, whereas splenic CFU-GM/CFU-granulocyte-erythrocyte-megakaryocyte-monocyte was only reduced by 50% in both Sl/Sld and littermate control mice. Thus, there remained a significant SCF/G-CSF-independent effect of IL-17 on splenic granulopoiesis, resulting in a preservation of mature circulating granulocytes. IL-17 is a cytokine that potentially interconnects lymphocytic and myeloid host defense and may have potential for therapeutic development.
Linkage of Foreign Carrier Protein to a Self-Tumor Antigen Enhances the Immunogenicity of a Pulsed Dendritic Cell Vaccine
Authors: Timmerman John M. , Levy Ronald 
Published: April 2014

AbstractThe unique Ag-presenting capabilities of dendritic cells (DCs) make them attractive vehicles for the delivery of therapeutic cancer vaccines. While tumor Ag-pulsed DC vaccination has shown promising results in a variety of murine tumor models and early clinical trials, the optimal form of tumor Ag for use in DC pulsing has not been determined. We have studied DC vaccination using alternative forms of a soluble protein tumor Ag, the tumor-specific Ig idiotype (Id) expressed by a murine B cell lymphoma. Vaccination of mice with Id-pulsed DCs was able to induce anti-Id Abs only when the Id was modified to constitute a hapten-carrier system. DCs pulsed with Id proteins modified to include foreign constant regions, foreign constant regions plus GM-CSF, or linkage to keyhole limpet hemocyanin (KLH) carrier protein were increasingly potent in their ability to elicit anti-Id Abs. Vaccination with Id-KLH-pulsed DCs induced tumor-protective immunity superior to that obtained with Id-KLH plus a chemical adjuvant, and protection was not dependent upon effector T cells. Rather, protection was associated with the induction of high titers of anti-Id Abs of the IgG2a subclass, characteristic of a Th1 response. These findings have implications for the design of therapeutic Ag-pulsed DC vaccines for cancer immunotherapy in humans.
In BALB/c Mice, IL-4 Production During the Initial Phase of Infection withLeishmania majorIs Necessary and Sufficient to Instruct Th2 Cell Development Resulting in Progressive Disease
Authors: Himmelrich Hayo , Launois Pascal , Maillard Ivan , Biedermann Tilo , Tacchini-Cottier Fabienne , Locksley Richard M. , Röcken Martin , Louis Jacques A. 
Published: April 2014

AbstractIn contrast to intact BALB/c mice, BALB/c mice rendered deficient in Vβ4+ CD4+ T cells develop a Th1 response to infection with Leishmania major and are resistant. Vβ4-deficient BALB/c mice are unable to generate the early IL-4 transcription occurring in Vβ4 Vα8 CD4+ T cells of BALB/c mice within 1 day of infection. Here we demonstrate that treatment of Vβ4-deficient BALB/c mice with IL-4 during the first 64 h after infection instructs Th2 cell development and susceptibility to infection. The demonstrated inability of IL-4 to reverse the resistant phenotype of BALB/c mice treated with anti-CD4 mAb the day before infection suggest that these effects of IL-4 require its interaction with CD4+ T cells. In contrast to draining lymph node cells from BALB/c mice, cells from Vβ4-deficient BALB/c mice remain responsive to IL-12 following infection. Strikingly, administration of IL-4 to Vβ4-deficient BALB/c mice renders their lymph node cells unresponsive to IL-12 by down-regulating IL-12R β2-chain expression. This study directly demonstrates that in BALB/c mice IL-4 is necessary and sufficient to initiate the molecular events steering Th2 cell maturation and susceptibility to L. major.
Biological Correlates of Capsular (Quellung) Reactions ofCryptococcus neoformans
Authors: MacGill Tracy C. , MacGill Randall S. , Casadevall Arturo , Kozel Thomas R. 
Published: April 2014

AbstractThe capsular swelling or quellung reaction was reported almost 100 years ago and described the effect of Abs on the appearance of microbial capsules. Despite widespread use to assess Ab binding to capsules, relatively little is known as to the mechanism of this effect or its biological consequences. The fungus Cryptococcus neoformans is an attractive system to study capsule reactions because it has a large polysaccharide capsule that is readily visible by light microscopy. When viewed by differential interference contrast microscopy, binding of mAb to C. neoformans cells produced two distinct capsular reactions that depended on the Ab epitope specificity and the yeast serotype. In the first pattern, termed “rim,” the capsule appears transparent with a highly refractive outer edge. In the second pattern, termed “puffy,” the capsule appears opaque and lacks a highly refractive outer rim. mAbs that bind with a rim pattern suppress the overall rate of C3 deposition on the yeast via the classical and alternative complement pathways. In contrast, mAbs that bind with a puffy pattern do not affect C3 deposition. Protective and nonprotective IgM mAbs produce rim and puffy patterns, respectively. These results indicate that: 1) capsule reactions are a consequence of Ab-induced changes in capsular refractive index; 2) the type of capsule reaction depends on the Ab specificity; and 3) Ab-induced changes in refractive index correlate with biological activities important for host defense against C. neoformans. Our results provide the first evidence associating distinct capsule reaction patterns with Ab biological activity.
Intersection of Group I CD1 Molecules and Mycobacteria in Different Intracellular Compartments of Dendritic Cells
Authors: Schaible Ulrich E. , Hagens Kristine , Fischer Karsten , Collins Helen L. , Kaufmann Stefan H. E. 
Published: April 2014

AbstractHuman CD1a, CD1b, and CD1c molecules can present mycobacterial glycolipids to T cells. Because phagosomes containing viable mycobacteria represent early endosomal compartments, we studied where mycobacterial glycolipids intersect with CD1 molecules in infected APC. CD1b and CD1c, but not CD1a, localized to late endosomes/lysosomes. CD1a and CD1c were predominantly expressed on the cell surface and in mycobacterial phagosomes of the early endosomal stage. In contrast, CD1b was present in a subset of mycobacterial phagosomes representing mature phagolysosomes. Released mycobacterial glycolipids including lipoarabinomannan and phosphatidylinositol mannosides were transported from the phagosome into late endosomes/lysosomes and to uninfected bystander cells. The macrophage mannose receptor, which has been implicated in glycolipid uptake by APC for CD1b-mediated presentation, was absent from mycobacterial phagosomes and may therefore not be involved in trafficking of glycolipids between phagosomes and late endosomes/lysosomes. In conclusion, all three CD1 molecules have access to mycobacteria and glycolipids thereof, but at different intracellular sites. This allows sampling by CD1a, CD1b, and CD1c of mycobacterial glycolipids from different intracellular sites of the infected cell, which has important implications for processing and presentation of such Ags during mycobacterial infections.
Secretory Phospholipases A2 Induce β-Glucuronidase Release and IL-6 Production from Human Lung Macrophages
Authors: Triggiani Massimo , Granata Francescopaolo , Oriente Alfonso , De Marino Valeria , Gentile Marco , Calabrese Cecilia , Palumbo Cristiana , Marone Gianni 
Published: April 2014

AbstractSecretory phospholipases A2 (sPLA2s) are a group of extracellular enzymes that release fatty acids at the sn-2 position of phospholipids. Group IIA sPLA2 has been detected in inflammatory fluids, and its plasma level is increased in inflammatory diseases. To investigate a potential mechanism of sPLA2-induced inflammation we studied the effect of group IA (from cobra venom) and group IIA (human synovial) sPLA2s on human macrophages. Both sPLA2s induced a concentration- and Ca2+-dependent, noncytotoxic release of β-glucuronidase (16.2 ± 2.4% and 13.1 ± 1.5% of the total content with groups IA and IIA, respectively). Both sPLA2s also increased the rate of secretion of IL-6 and enhanced the expression of IL-6 mRNA. Preincubation of macrophages with inhibitors of the hydrolytic activity of sPLA2 or cytosolic PLA2 did not influence the release of β-glucuronidase. Incubation of macrophages with p-aminophenyl-mannopyranoside-BSA (mp-BSA), a ligand of the mannose receptor, also resulted in β-glucuronidase release. However, while preincubation of macrophages with mp-BSA had no effect on β-glucuronidase release induced by group IIA sPLA2, it enhanced that induced by group IA sPLA2. A blocking Ab anti-mannose receptor inhibited both mp-BSA- and group IIA-induced β-glucuronidase release. Taken together, these data indicate that group IA and IIA sPLA2s activate macrophages with a mechanism independent from their enzymatic activities and probably related to the activation of the mannose receptor or sPLA2-specific receptors. The secretion of enzymes and cytokines induced by sPLA2s from human macrophages may play an important role in inflammation and tissue damage associated with the release of sPLA2s.
IFN-γ and TNF Regulate Macrophage Expression of the Chemotactic S100 Protein S100A8
Authors: Xu Ken , Geczy Carolyn L. 
Published: April 2014

AbstractThe murine calcium-binding protein S100A8 is a potent chemoattractant for neutrophils and monocytes in vivo and in vitro but may also play a protective role. We show that the kinetics of induction of S100A8 mRNA in elicited murine macrophages (Mac) by LPS, IFN-γ, and TNF were distinct from the C-C chemokines monocyte chemoattractant protein-1 (MCP-1), macrophage-inflammatory protein-1α (MIP-1α), and RANTES. Monomeric S100A8 was predominantly secreted. IFN substantially increased S100A8 mRNA levels after 1 h with optimal induction after 12 h; induction by TNF was slower and more sustained. TNF did not up-regulate MCP-1 and MIP-1α mRNA in these cells. Luciferase reporter assays confirmed that LPS and IFN induce S100A8 gene transcription and mRNA in LPS-treated Mac showed little decay over 16 h, whereas transcripts induced by IFN and TNF were markedly less stable. Newly synthesized proteins may be required for mRNA transcription and stabilization in response to LPS. S100A9 associates with A8 in neutrophils, but was not coinduced with S100A8. S100A8 gene induction in Mac stimulated with LPS and IFN may be modulated by mobilization of intracellular Ca2+ concentration from distinct intracellular stores and/or the extracellular compartment and by distinct pathways involving protein kinase C and leading to activation of mitogen-activated protein kinase.
Macrophage Colony-Stimulating Factor Antagonists Inhibit Replication of HIV-1 in Human Macrophages
Authors: Kutza Joseph , Crim Lynne , Feldman Steven , Hayes Mark P. , Gruber Marion , Beeler Judy , Clouse Kathleen A. 
Published: April 2014

AbstractMacrophages infected with HIV-1 produce high levels of M-CSF and macrophage-inflammatory protein-1α (MIP-1α). M-CSF facilitates the growth and differentiation of macrophages, while the chemotactic properties of MIP-1α attract both T lymphocytes and macrophages to the site of HIV infection. Studies described in this work indicate M-CSF may function in an autocrine/paracrine manner to sustain HIV replication, and data suggest possible therapeutic strategies for decreasing viral load following HIV infection. We show that macrophage infection with measles virus or respiratory syncytial virus, in contrast to HIV-1, results in production of MIP-1α, but not M-CSF. Thus, M-CSF appears to be specifically produced upon infection of macrophages with HIV-1. Furthermore, addition of M-CSF antagonists to HIV-1-infected macrophages, including anti-M-CSF monoclonal or polyclonal Abs or soluble M-CSF receptors, dramatically inhibited HIV-1 replication and reduced production of MIP-1α. Our results suggest that biologic antagonists for M-CSF may represent novel strategies for inhibiting the spread of HIV-1 by 1) blocking virus replication in macrophages, 2) reducing recruitment of HIV-susceptible T cells and macrophages by MIP-1α, and 3) preventing the establishment and maintenance of infected macrophages as a reservoir for HIV.
Induction of AIDS Virus-Specific CTL Activity in Fresh, Unstimulated Peripheral Blood Lymphocytes from Rhesus Macaques Vaccinated with a DNA Prime/Modified Vaccinia Virus Ankara Boost Regimen
Authors: Allen Todd M. , Vogel Thorsten U. , Fuller Deborah H. , Mothé Bianca R. , Steffen Susan , Boyson Jon E. , Shipley Tim , Fuller Jim , Hanke Tomas , Sette Alessandro , Altman John D. , Moss Bernard , McMichael Andrew J. , Watkins David I. 
Published: April 2014

AbstractThe observed role of CTL in the containment of AIDS virus replication suggests that an effective HIV vaccine will be required to generate strong CTL responses. Because epitope-based vaccines offer several potential advantages for inducing strong, multispecific CTL responses, we tested the ability of an epitope-based DNA prime/modified vaccinia virus Ankara (MVA) boost vaccine to induce CTL responses against a single SIVgag CTL epitope. As assessed using both 51Cr release assays and tetramer staining of in vitro stimulated PBMC, DNA vaccinations administered to the skin with the gene gun induced and progressively increased p11C, C→M (CTPYDINQM)-specific CD8+ T lymphocyte responses in six of six Mamu-A*01+ rhesus macaques. Tetramer staining of fresh, unstimulated PBMC from two of the DNA-vaccinated animals indicated that as much as 0.4% of all CD3+/CD8α+ T lymphocytes were specific for the SIVgag CTL epitope. Administration of MVA expressing the SIVgag CTL epitope further boosted these responses, such that 0.8–20.0% of CD3+/CD8α+ T lymphocytes in fresh, unstimulated PBMC were now Ag specific. Enzyme-linked immunospot assays confirmed this high frequency of Ag-specific cells, and intracellular IFN-γ staining demonstrated that the majority of these cells produced IFN-γ after peptide stimulation. Moreover, direct ex vivo SIV-specific cytotoxic activity could be detected in PBMC from five of the six DNA/MVA-vaccinated animals, indicating that this epitope-based DNA prime/MVA boost regimen represents a potent method for inducing high levels of functionally active, Ag-specific CD8+ T lymphocytes in non-human primates.
Tumor Cells Present MHC Class II-Restricted Nuclear and Mitochondrial Antigens and Are the Predominant Antigen Presenting Cells In Vivo
Authors: Qi Ling , Rojas José-Manuel , Ostrand-Rosenberg Suzanne 
Published: April 2014

AbstractMHC class II-restricted tumor Ags presented by class II+ tumor cells identified to date are derived from proteins expressed in the cytoplasm or plasma membrane of tumor cells. It is unclear whether MHC class II+ tumor cells present class II-restricted epitopes derived from other intracellular compartments, such as nuclei and/or mitochondria, and whether class II+ tumor cells directly present Ag in vivo. To address these questions, a model Ag, hen egg lysozyme, was targeted to various subcellular compartments of mouse sarcoma cells, and the resulting cells were tested for presentation of three lysozyme epitopes in vitro and for presentation of nuclear Ag in vivo. In in vitro studies, Ags localized to all tested compartments (nuclei, cytoplasm, mitochondria, and endoplasmic reticulum) are presented in the absence invariant chain and H-2M. Coexpression of invariant chain and H-2M inhibit presentation of some, but not all, of the epitopes. In vivo studies demonstrate that class II+ tumor cells, and not host-derived cells, are the predominant APC for class II-restricted nuclear Ags. Because class II+ tumor cells are effective APC in vivo and probably present novel tumor Ag epitopes not presented by host-derived APC, their inclusion in cancer vaccines may enhance activation of tumor-reactive CD4+ T cells.
Fas and Fas Ligand Expressed on Cells of the Immune System, not on the Target Tissue, Control Induction of Experimental Autoimmune Uveitis
Authors: Wahlsten Jennifer L. , Gitchell Heather L. , Chan Chi-Chao , Wiggert Barbara , Caspi Rachel R. 
Published: April 2014

AbstractThe Fas-Fas ligand (FasL) interaction is important for maintaining lymphocyte homeostasis by signaling for activation-induced cell death. Mice homozygous for the lpr or gld mutations do not express functional Fas or FasL, respectively, and spontaneously develop progressive autoimmune symptoms. Recent studies implicated expression of FasL on immunologically privileged tissues in protection from immune-mediated damage. Conversely, tissue expression of Fas may facilitate damage. We evaluated the susceptibility of lpr and gld mice to induction of experimental autoimmune uveitis (EAU), a T cell-mediated autoimmune disease induced with retinal Ags, which targets the neural retina. gld as well as lpr mice immunized with a retinal Ag developed disease of lower incidence and severity than wild-type controls. Delayed hypersensitivity responses were not significantly different among immunized gld, lpr, or wild-type mice, although in vitro Ag-specific lymphocyte responses of the mutant mice were lower. To evaluate whether the diminished ability of gld and lpr mice to develop EAU was due to a defect at the level of the tissue or the immune system, radiation bone marrow chimeras constructed between wild-type and mutant mice were immunized to induce EAU. Mutant recipients of wild-type bone marrow, but not wild-type recipients of mutant bone marrow, developed normal disease scores. These results indicate that normal expression of Fas and of FasL on cells of the immune system is important for EAU expression. Unexpectedly, neither lack of Fas nor lack of FasL on the ocular tissues affected expression of EAU.
T Cell Reactivity to Heat Shock Protein 60 in Diabetes-Susceptible and Genetically Protected Nonobese Diabetic Mice Is Associated with a Protective Cytokine Profile
Authors: van Halteren Astrid G.S. , Mosselman Bart , Roep Bart O. , van Eden Willem , Cooke Anne , Kraal Georg , Wauben Marca H. M. 
Published: April 2014

AbstractSpontaneous onset of pancreatic β cell destruction in the nonobese diabetic (NOD) mouse is preceded by the induction of autoreactive T cells, which recognize a variety of autoantigens. The 60-kDa endogenous (murine) heat shock protein 60 (hsp60) has been proposed to be one of the key autoantigens. Here we demonstrate that subcutaneous immunization of normoglycemic NOD mice with highly homologous mycobacterial or murine hsp60 activates T cells in the spleen that produce high levels of IL-10 upon restimulation in vitro with either hsp60 protein. In time, increasing levels of hsp60-induced IL-10 could be detected in NOD mice, but not in age- and MHC class II-matched BiozziABH mice, which lack any sign of pancreatic inflammation. These results suggest that the IL-10 responses in NOD mice are primarily driven by endogenous inflammation. Genetically protected NOD-asp mice, showing a less progressive development of insulitis, demonstrated a similar increase in hsp60-induced IL-10 in time compared with wild-type NOD mice. Taken together, our results suggest that endogenous hsp60 is not a primary autoantigen in diabetes but is possibly associated with regulation of insulitis. Moreover, the capacity to respond to (self) hsp60 is independent of the MHC class II-associated genetic predisposition to diabetes.
Competitive Displacement of pTα by TCR-α During TCR Assembly Prevents Surface Coexpression of Pre-TCR and αβ TCR
Authors: Trop Sébastien , Rhodes Michele , Wiest David L. , Hugo Patrice , Zúñiga-Pflücker Juan Carlos 
Published: April 2014

AbstractDuring αβ T cell development, CD4−CD8− thymocytes first express pre-TCR (pTα/TCR-β) before their differentiation to the CD4+CD8+ stage. Positive selection of self-tolerant T cells is then determined by the αβ TCR expressed on CD4+CD8+ thymocytes. Conceivably, an overlap in surface expression of these two receptors would interfere with the delicate balance of thymic selection. Therefore, a mechanism ensuring the sequential expression of pre-TCR and TCR must function during thymocyte development. In support of this notion, we demonstrate that expression of TCR-α by immature thymocytes terminates the surface expression of pre-TCR. Our results reveal that expression of TCR-α precludes the formation of pTα/TCR-β dimers within the endoplasmic reticulum, leading to the displacement of pre-TCR from the cell surface. These findings illustrate a novel posttranslational mechanism for the regulation of pre-TCR expression, which may ensure that αβ TCR expression on thymocytes undergoing selection is not compromised by the expression of pre-TCR.