bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gene Structure and Promoter Variation of Expressed and Nonexpressed Variants of the KIR2DL5 Gene
Authors: Vilches Carlos , Gardiner Clair M. , Parham Peter 
Published: April 2014

Abstract
Two variants of the novel KIR2DL5 gene (KIR2DL5.1 and .2) were identified in genomic DNA of a single donor. However, only the KIR2DL5.1 variant was transcribed in PBMC. In this study, analysis of seven additional donors reveals two new variants of the KIR2DL5 gene and indicates that transcription, or its lack, are consistently associated with particular variants of this gene. Comparison of the complete nucleotide sequences of the exons and introns of KIR2DL5.1 and KIR2DL5.2 reveals no structural abnormalities, but similar open reading frames for both variants. In contrast, the promoter region of KIR2DL5 shows a high degree of sequence polymorphism that is likely relevant for expression. Substitution within a putative binding site for the transcription factor acute myeloid leukemia gene 1 could determine the lack of expression for some KIR2DL5 variants.
Three-Dimensional Structure of the Fab from a Human IgM Cold Agglutinin
Authors: Cauerhff Ana , Braden Bradford C. , Carvalho Julio Garcia , Aparicio Ricardo , Polikarpov Igor , Leoni Juliana , Goldbaum Fernando A. 
Published: April 2014

AbstractCold agglutinins (CAs) are IgM autoantibodies characterized by their ability to agglutinate in vitro RBC at low temperatures. These autoantibodies cause hemolytic anemia in patients with CA disease. Many diverse Ags are recognized by CAs, most frequently those belonging to the I/i system. These are oligosaccharides composed of repeated units of N-acetyllactosamine, expressed on RBC. The three-dimensional structure of the Fab of KAU, a human monoclonal IgM CA with anti-I activity, was determined. The KAU combining site shows an extended cavity and a neighboring pocket. Residues from the hypervariable loops VHCDR3, VLCDR1, and VLCDR3 form the cavity, whereas the small pocket is defined essentially by residues from the hypervariable loops VHCDR1 and VHCDR2. This fact could explain the VH4-34 germline gene restriction among CA. The KAU combining site topography is consistent with one that binds a polysaccharide. The combining site overall dimensions are 15 Å wide and 24 Å long. Conservation of key binding site residues among anti-I/i CAs indicates that this is a common feature of this family of autoantibodies. We also describe the first high resolution structure of the human IgM CH1:CL domain. The structural analysis shows that the CH1-CL interface is mainly conserved during the isotype switch process from IgM to IgG1.
Resistance to Apoptosis in HIV-Infected CD4+ T Lymphocytes Is Mediated by Macrophages: Role for Nef and Immune Activation in Viral Persistence
Authors: Mahlknecht Ulrich , Deng Cheng , Lu Michael C. , Greenough Thomas C. , Sullivan John L. , O’Brien William A. , Herbein Georges 
Published: April 2014

AbstractApoptosis or programmed cell death may play a critical role in AIDS pathogenesis through depletion of both CD4+ and CD8+ T lymphocytes. Using a reporter virus, a recombinant HIV infectious clone expressing the green fluorescent protein (GFP), apoptosis was measured in productively infected CD4+ T lymphocytes, in the presence and absence of autologous macrophages. The presence of macrophages in the culture increased the frequency of nonapoptotic GFP-positive productively infected CD4+ T lymphocytes. The appearance of nonapoptotic productively infected CD4+ T lymphocytes in the culture required intercellular contacts between macrophages and PBLs and the expression of the HIV Nef protein. The presence of macrophages did not reduce apoptosis when CD4+ T lymphocytes were infected with a GFP-tagged virus deleted for the nef gene. TNF-α (TNF) expressed on the surface of macrophages prevented apoptosis in nef-expressing, productively infected CD4+ T lymphocytes. Similarly, following TNF stimulation, apoptosis was diminished in Jurkat T cells transfected with a nef-expressing plasmid. TNF stimulation of nef-expressing Jurkat T cells resulted in NF-κB hyperactivation, which has been shown to deliver anti-apoptotic signals. Our results indicate that intercellular contacts with macrophages increase the rate of productively infected nonapoptotic CD4+ T lymphocytes. The survival of productively infected CD4+ T lymphocytes requires Nef expression as well as activation by TNF expressed on the surface of macrophages and might participate in the formation and maintenance of viral reservoirs in HIV-infected persons.
Eotaxin Is Specifically Cleaved by Hookworm Metalloproteases Preventing Its Action In Vitro and In Vivo
Authors: Culley Fiona J. , Brown Alan , Conroy Dolores M. , Sabroe Ian , Pritchard David I. , Williams Timothy J. 
Published: April 2014

AbstractEotaxin is a potent eosinophil chemoattractant that acts selectively through CCR3, which is expressed on eosinophils, basophils, mast cells, and Th2-type T cells. This arm of the immune system is believed to have evolved to control helminthic parasites. We hypothesized that helminths may employ mechanisms to inhibit eosinophil recruitment, to prolong worm survival in the host. We observed that the excretory/secretory products of the hookworm Necator americanus inhibited eosinophil recruitment in vivo in response to eotaxin, but not leukotriene B4, a phenomenon that could be prevented by the addition of protease inhibitors. Using Western blotting, N. americanus supernatant was shown to cause rapid proteolysis of eotaxin, but not IL-8 or eotaxin-2. N. americanus homogenate was fractionated by gel filtration chromatography, and a FACS-based bioassay measured the ability of each fraction to inhibit the activity of a variety of chemokines. This resulted in two peaks of eotaxin-degrading activity, corresponding to ∼15 and 50 kDa molecular mass. This activity was specific for eotaxin, as responses to other agonists tested were unaffected. Proteolysis of eotaxin was prevented by EDTA and phenanthroline, indicating that metalloprotease activity was involved. Production of enzymes inactivating eotaxin may be a strategy employed by helminths to prevent recruitment and activation of eosinophils at the site of infection. As such this represents a novel mechanism of regulation of chemokine function in vivo. The existence of CCR3 ligands other than eotaxin (e.g., eotaxin-2) may reflect the evolution of host counter measures to parasite defense systems.
Identification of Major Epitopes ofMycobacterium tuberculosisAG85B That Are Recognized by HLA-A*0201-Restricted CD8+ T Cells in HLA-Transgenic Mice and Humans
Authors: Geluk Annemieke , van Meijgaarden Krista E. , Franken Kees L. M. C. , Drijfhout Jan W. , D’Souza Sushila , Necker Antje , Huygen Kris , Ottenhoff Tom H. M. 
Published: April 2014

AbstractCD8+ T cells are thought to play an important role in protective immunity to tuberculosis. Although several nonprotein ligands have been identified for CD1-restricted CD8+ CTLs, epitopes for classical MHC class I-restricted CD8+ T cells, which most likely represent a majority among CD8+ T cells, have remained ill defined. HLA-A*0201 is one of the most prevalent class I alleles, with a frequency of over 30% in most populations. HLA-A2/Kb transgenic mice were shown to provide a powerful model for studying induction of HLA-A*0201-restricted immune responses in vivo. The Ag85 complex, a major component of secreted Mycobacterium tuberculosis proteins, induces strong CD4+ T cell responses in M. tuberculosis-infected individuals, and protection against tuberculosis in Ag85-DNA-immunized animals. In this study, we demonstrate the presence of HLA class I-restricted, CD8+ T cells against Ag85B of M. tuberculosis in HLA-A2/Kb transgenic mice and HLA-A*0201+ humans. Moreover, two immunodominant Ag85 peptide epitopes for HLA-A*0201-restricted, M. tuberculosis-reactive CD8+ CTLs were identified. These CD8+ T cells produced IFN-γ and TNF-α and recognized Ag-pulsed or bacillus Calmette-Guérin-infected, HLA-A*0201-positive, but not HLA-A*0201-negative or uninfected human macrophages. This CTL-mediated killing was blocked by anti-CD8 or anti-HLA class I mAb. Using fluorescent peptide/HLA-A*0201 tetramers, Ag85-specific CD8+ T cells could be visualized in bacillus Calmette-Guérin-responsive, HLA-A*0201+ individuals. Collectively, our results demonstrate the presence of HLA class I-restricted CD8+ CTL against a major Ag of M. tuberculosis and identify Ag85B epitopes that are strongly recognized by HLA-A*0201-restricted CD8+ T cells in humans and mice. These epitopes thus represent potential subunit components for the design of vaccines against tuberculosis.
Delayed Inflammatory Response toPneumocystis cariniiInfection in Neonatal Mice Is Due to an Inadequate Lung Environment
Authors: Garvy Beth A. , Qureshi Mahboob H. 
Published: April 2014

AbstractChallenge of neonatal mice with an intranasal inoculation of Pneumocystis carinii results in a subclinical infection that takes 6 wk to resolve, whereas adult mice resolve a comparable challenge within 3 wk. This delayed clearance is due to a delayed inflammatory response in neonatal mice; however, the reason for this delay has been unknown. To determine whether the neonatal lung environment is sufficient to attract immunocompetent lymphocytes into the lungs, an adoptive transfer strategy was employed in which splenocytes from adult BALB/c mice were transferred into P. carinii-infected neonatal or adult SCID mice. All adults, but no pups, resolved their infections by day 37 postreconstitution. Despite reconstitution with adult splenocytes, pups had a negligible lung inflammatory response until day 24, whereas adult mice had activated CD4+ and CD8+ cells in the lung by day 13. The delay in neonates corresponded to delayed kinetics of expression of lung cytokines TNF-α and IFN-γ mRNA and chemokines lymphotactin, RANTES, and macrophage inflammatory protein-1β mRNA. Phagocytic cells from neonatal mice were significantly less efficient than adult cells at migrating to the draining lymph nodes after phagocytosing fluorescent beads. There were fewer dendritic cells and Ia+ myeloid cells in the lungs of P. carinii-infected neonatal mice compared with adults. These data indicate that the lung environment of neonatal mice is insufficient for migration of T cells, due at least in part to inefficient phagocytosis and migration of APCs to the lymph nodes as well as delayed chemokine and TNF-α mRNA expression.
The Peroxynitrite Scavenger Uric Acid Prevents Inflammatory Cell Invasion into the Central Nervous System in Experimental Allergic Encephalomyelitis through Maintenance of Blood-Central Nervous System Barrier Integrity
Authors: Kean Rhonda B. , Spitsin Sergei V. , Mikheeva Tatiana , Scott Gwen S. , Hooper D. Craig 
Published: April 2014

Abstract
Uric acid (UA), a product of purine metabolism, is a known scavenger of peroxynitrite (ONOO−), which has been implicated in the pathogenesis of multiple sclerosis and experimental allergic encephalomyelitis (EAE). To determine whether the known therapeutic action of UA in EAE is mediated through its capacity to inactivate ONOO− or some other immunoregulatory phenomenon, the effects of UA on Ag presentation, T cell reactivity, Ab production, and evidence of CNS inflammation were assessed. The inclusion of physiological levels of UA in culture effectively inhibited ONOO−-mediated oxidation as well as tyrosine nitration, which has been associated with damage in EAE and multiple sclerosis, but had no inhibitory effect on the T cell-proliferative response to myelin basic protein (MBP) or on APC function. In addition, UA treatment was found to have no notable effect on the development of the immune response to MBP in vivo, as measured by the production of MBP-specific Ab and the induction of MBP-specific T cells. The appearance of cells expressing mRNA for inducible NO synthase in the circulation of MBP-immunized mice was also unaffected by UA treatment. However, in UA-treated animals, the blood-CNS barrier breakdown normally associated with EAE did not occur, and inducible NO synthase-positive cells most often failed to reach CNS tissue. These findings are consistent with the notion that UA is therapeutic in EAE by inactivating ONOO−, or a related molecule, which is produced by activated monocytes and contributes to both enhanced blood-CNS barrier permeability as well as CNS tissue pathology.
Inflammatory Properties of IgG Modified by Oxygen Radicals and Peroxynitrite
Authors: Uesugi Masaaki , Yoshida Koji , Jasin Hugo E. 
Published: April 2014

AbstractIn inflammatory arthritis, there is evidence indicating that the affected tissues produce large amounts of oxygen-free radicals and NO. Herein, we examine the biologic effects of exposure of IgG to hypochlorous acid (HOCl) and peroxynitrite (ONOO). The concentrations of IgG modified by chlorination and nitrosation were measured in synovial fluids from inflammatory and noninflammatory arthritis. Human IgG was exposed to increasing concentrations of HOCl and ONOO, and the resulting products were tested for complement component binding; binding to FcγRI; activation of polymorphonuclear neutrophils; effect on the Ab-combining site of Abs; and in vivo inflammatory activity in a rabbit model of acute arthritis. Rheumatoid synovial fluids contained significantly greater concentrations of nitrosated and chlorinated IgG compared with ostearthritic specimens. In vitro exposure of human IgG to HOCl and ONOO resulted in a concentration-dependent decrease in C3 and C1q fixation. The decrease in Fc domain-dependent biologic functions was confirmed by competitive binding studies to the FcγRI of U937 cells. HOCl-treated IgG monomer was 10 times less effective in competing for binding compared with native IgG, and ONOO-treated IgG was 2.5 times less effective. The modified IgGs were also ineffective in inducing synthesis of H2O2 by human PMN. The Ag-binding domains of IgG also showed a concentration-dependent decrease in binding to Ag. The ability of the modified IgGs to induce acute inflammation in rabbit knees decreased 20-fold as gauged by the intensity of the inflammatory cell exudates. These studies clarify the modulating role of biological oxidants in inflammatory processes in which Ag-autoantibody reactions and immune complex pathogenesis may play an important role.
The N-Terminal Lipopeptide of a 44-kDa Membrane-Bound Lipoprotein ofMycoplasma salivariumIs Responsible for the Expression of Intercellular Adhesion Molecule-1 on the Cell Surface of Normal Human Gingival Fibroblasts
Authors: Shibata Ken-ichiro , Hasebe Akira , Into Takeshi , Yamada Masanori , Watanabe Tsuguo 
Published: April 2014

AbstractThe activities to induce TNF-α production by a monocytic cell line, THP-1, and ICAM-1 expression and IL-6 production by human gingival fibroblasts were detected in plural membrane lipoproteins of Mycoplasma salivarium. Although SDS-PAGE of the lipoproteins digested by proteinase K did not reveal any protein bands with molecular masses higher than approximately10 kDa, these activities were detected in the front of the gel. A lipoprotein with a molecular mass of 44 kDa (Lp44) was purified. Proteinase K did not affect the ICAM-1 expression-inducing activity of Lp44, but lipoprotein lipase abrogated the activity. These results suggested that the proteinase K-resistant and low molecular mass entity, possibly the N-terminal lipid moiety, played a key role in the expression of the activity. The N-terminal lipid moiety of Lp44 was purified from Lp44 digested with proteinase K by HPLC. Judging from the structure of microbial lipopeptides as well as the amino acid sequence and infrared spectrum of Lp44, the structure of the N-terminal lipid moiety of Lp44 was speculated to be S-(2, 3-bisacyloxypropyl)-cysteine-GDPKHPKSFTEWV-. Its analogue, S-(2, 3-bispalmitoyloxypropyl)-cysteine-GDPKHPKSF, was synthesized. The lipopeptide was similar to the N-terminal lipid moiety of Lp44 in the infrared spectrum and the ICAM-1 expression-inducing activity. Thus, this study suggested that the active entity of Lp44 was its N-terminal lipopeptide moiety, the structure of which was very similar to S-(2, 3-bispalmitoyloxypropyl)-cysteine-GDPKHPKSF.
Reduced Susceptibility of Nonobese Diabetic Mice to TNF-α andd-Galactosamine-Mediated Hepatocellular Apoptosis and Lethality
Authors: Bahjat Frances R. , Dharnidharka Vikas R. , Fukuzuka Kunitaro , Morel Laurence , Crawford James M. , Clare-Salzler Michael J. , Moldawer Lyle L. 
Published: April 2014

AbstractNonobese diabetic (NOD/LtJ or NOD) mice are resistant to doses of LPS and d-galactosamine that uniformly produce lethality in C57BL/6J (B6) mice (p &lt; 0.01). Liver caspase-3-like activity, serum transaminase levels (both p &lt; 0.05), and the numbers of apoptotic liver nuclei were also reduced in NOD compared with B6 mice treated with LPS (100 ng) and d-galactosamine (8 mg). NOD mice were also at least 100-fold more resistant to recombinant human TNF-α and d-galactosamine treatment than B6 mice (p &lt; 0.001). Binding of recombinant human TNF-α to splenocytes from NOD mice was similar to that seen in B6 mice, suggesting that the defect in responsiveness was not due to an inability of recombinant human TNF-α to bind the NOD TNF type 1 (p55) receptor. Because the TNF type 1 (p55) receptor shares a common signaling pathway with Fas (CD95), NOD and B6 mice were treated with the Fas agonist antibody, Jo-2. Surprisingly, NOD mice were as sensitive as B6 mice to Fas-induced lethality and hepatic injury. In addition, primary hepatocytes isolated from NOD mice and cultured in vitro in the presence of d-galactosamine with or without TNF-α were found to be resistant to apoptosis and cytotoxicity when compared with B6 mice. In contrast, Jo-2 treatment produced similar increases in caspase-3 activity and cytotoxicity in primary hepatocytes from NOD and B6 mice. The resistance to LPS- and TNF-α-mediated lethality and hepatic injury in d-galactosamine-sensitized NOD mice is apparently due to a post-TNFR binding defect, and independent of signaling pathways shared with Fas.
Transcriptional Analysis of Multiple Sclerosis Brain Lesions Reveals a Complex Pattern of Cytokine Expression
Authors: Baranzini Sergio E. , Elfstrom Carita , Chang Sheng-Yung , Butunoi Catalin , Murray Ronald , Higuchi Russell , Oksenberg Jorge R. 
Published: April 2014

Abstract
Multiple sclerosis (MS) is a common and severe neurological disorder associated with an autoimmune response directed against myelin components within the CNS. Lymphocyte activation, extravasation, and recruitment, as well as effector function, involves the turning on and off of a number of genes, thus triggering specific transcriptional pathways. The characterization of the transcriptome in MS lesions should provide a better understanding of the mechanisms that generate and sustain the pathogenic immune response in this disease. Here we performed transcriptional profiling of 56 relevant genes in brain specimens from eight MS patients and eight normal controls by kinetic RT-PCR. Results showed a high transcriptional activity for the gene coding for myelin basic protein (MBP); however, it was not differentially expressed in MS samples, suggesting that remyelination is an active process also in the noninflammatory brain. CD4 and HLA-DRα transcripts were dramatically increased in MS as compared with controls. This reveals a robust MHC class II up-regulation and suggests that Ag is being presented locally to activated T cells. Although analysis of cytokine and cytokine receptor genes expression showed predominantly increased levels of several Th1 molecules (TGF-β, RANTES, and macrophage-inflammatory protein (MIP)-1α) in MS samples, some Th2 genes (IL-3, IL-5, and IL-6/IL-6R) were found to be up-regulated as well. Similarly, both proinflammatory type (CCR1, CCR5) and immunomodulatory type (CCR4, CCR8) chemokine receptors were differentially expressed in the MS brain. Overall, our data suggest a complex regulation of the inflammatory response in human autoimmune demyelination.
Dendritic Cells, Infected with Vesicular Stomatitis Virus-Pseudotyped HIV-1, Present Viral Antigens to CD4+ and CD8+ T Cells from HIV-1-Infected Individuals
Authors: Granelli-Piperno Angela , Zhong Lei , Haslett Patrick , Jacobson Jeffrey , Steinman Ralph  M. 
Published: April 2014

Abstract
Nonreplicating vectors are being considered in HIV-1 vaccine design. However, nonreplicating viruses are typically weak immunogens, leading to efforts to target the vaccine to mature dendritic cells (DCs). We have studied a single-cycle form of HIV-1, prepared by pseudotyping envelope-defective HIV-1 plasmids with the envelope from vesicular stomatitis virus (VSV) G protein (VSV-G), to which most humans lack preexisting immunity. The nonreplicating, VSV/HIV-1 efficiently infected the immature stage of DC development, in this case represented by monocytes cultured with GM-CSF and IL-4. A majority of the cells reverse transcribed the HIV-1 RNA, and a minority expressed gag protein. The infected populations were further matured with CD40 ligand, leading to strong stimulation of autologous T cells from HIV-1-infected individuals, but not controls. Enriched CD8+ T cells from 12/12 donors released IFN-γ (50–300 enzyme-linked immunospots/200,000 T cells) and proliferated. Macrophages were much less efficient in expanding HIV-1-responsive T cells, and bulk mononuclear cells responded weakly to VSV/HIV-1. CD4+ T cells from at least half of the donors showed strong responses to VSV/HIV-1-infected DCs. Presentation to CD8+ T cells, but not to CD4+, was primarily through an endogenous pathway, because the responses were markedly reduced if envelope-defective virus particles or reverse transcriptase inhibitors were added. Therefore, nonreplicating vaccines can be targeted to immature DCs, which upon further maturation induce combined and robust CD4+ and CD8+ immunity.
Regulatory Defects in Cbl and Mitogen-Activated Protein Kinase (Extracellular Signal-Related Kinase) Pathways Cause Persistent Hyperexpression of CD40 Ligand in Human Lupus T Cells
Authors: Yi Yajun , McNerney Megan , Datta Syamal K. 
Published: April 2014

AbstractTo identify intrinsic defects in lupus, we studied short-term, CD4+ T cell lines that were established from 16 lupus patients (active or inactive) and 15 normal subjects by stimulating once with anti-CD3, anti-CD28, and IL-2. After resting, the pure CD4+ T cells were exposed to anergy-inducing stimulation with plate-bound anti-CD3 mAb in the absence of APC. Lupus T cells showed prolonged high level expression of CD40 ligand (CD40L, CD154) even in the face of anergy protocol, which shut down CD40L expression in normal T cells. The sustained CD40L expression in lupus T cells did not correlate with memory status or Th deviation, and was relatively independent of IL-2 or other autocrine or paracrine signals via CD28 or CTLA-4. Cyclosporin A could block CD40L expression by lupus T cells when added early during the anti-CD3 stimulation period, but only partially when added later, indicating that another mechanism regulates the prolonged hyperexpression of CD40L besides the Ca2+ ⇒ calcineurin-dependent NF-AT pathway. When exposed to the anergy protocol, lupus T cells, in marked contrast to normal T cells, did not phosphorylate Cbl/Cbl-b but continued to express strongly phosphorylated extracellular signal-regulated kinase (ERK); U0126, a specific inhibitor of mitogen-activated protein kinase kinase ⇒ ERK, could block both the early and the prolonged hyperexpression of CD40L. Thus, pathways regulating the activities of Cbl and one particular mitogen-activated protein kinase, ERK, are involved in the prolonged hyperexpression of CD40L in lupus T cells.