bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of a Novel Killer Cell Lectin-Like Receptor (KLRH1) Expressed by Alloreactive Rat NK Cells
Authors: Naper Christian , Hayashi Shigenari , Løvik Guro , Kveberg Lise , Niemi Eréne C. , Rolstad Bent , Dissen Erik , Ryan James C. , Vaage John T. 
Published: April 2014

AbstractNK cells have the ability to recognize and kill MHC-mismatched hemopoietic cells. In the present study, strain-specific differences in the rat NK allorecognition repertoire were exploited to generate Abs against receptors that may be involved in allogeneic responses. A mAb termed STOK9 was selected, and it reacted with subsets of NK cells and NKR-P1+ T cells from certain rat strains possessing highly alloreactive NK cells. The STOK9+ NK subset was broadly alloreactive and lysed Con A lymphoblast targets from a range of MHC-mismatched strains. The mAb STOK9 precipitated a 75-kDa dimeric glycoprotein from NK lysates. Expression cloning revealed that each monomer consisted of 231 aa with limited homology to other previously characterized killer cell lectin-like receptors (KLRs). This glycoprotein therefore constitutes a novel KLR branch, and it has been termed KLRH1. A gene in the central region of the natural killer gene complex on rat chromosome 4 encodes KLRH1. A mouse homolog appears to be present as deduced from analyses of genomic trace sequences. The function of KLRH1 is unknown, but it contains an immunoreceptor tyrosine-based inhibitory motif, suggesting an inhibitory function. The MHC haplotype of the host appears to influence KLRH1 expression, suggesting that it may function as an MHC-binding receptor on subsets of NK cells and T lymphocytes.
Heavy Chain V Region Diversity in the Duck-Billed Platypus (Ornithorhynchus anatinus): Long and Highly Variable Complementarity-Determining Region 3 Compensates for Limited Germline Diversity
Authors: Johansson Jeannette , Aveskogh Maria , Munday Barry , Hellman Lars 
Published: April 2014

AbstractIn this work, to study the emergence of the H chain V region repertoire during mammalian evolution, we present an analysis of 25 independent H chain V regions from a monotreme, the Australian duck-billed platypus, Ornithorhynchus anatinus. All the sequences analyzed were found to form a single branch within the clan III of mammalian V region sequences in a distance tree. However, compared with a classical V gene family this branch was more diversified in sequence. Sequence analysis indicates that the apparent lack of diversity in germline V segments is well compensated for by relatively long and highly diversified D and N nucleotides. In addition, extensive sequence variation was observed in the framework region 3. Furthermore, at least five and possibly seven different J segments seem to be actively used in recombination. Interestingly, internal cysteine bridges in the complementarity-determining region (CDR)3 loop, or between the CDR2 and CDR3 loops, are found in ∼36% of the platypus VH sequences. Such cysteine bridges have also been observed in cow, camel, and shark. Internal cysteine bridges may play a role in stabilizing long and diversified CDR3 and thereby have a role in increasing the affinity of the Ab-Ag interaction.
Identification of a NovelLy49Promoter That Is Active in Bone Marrow and Fetal Thymus
Authors: Saleh Ali , Makrigiannis Andrew P. , Hodge Deborah L. , Anderson Stephen K. 
Published: April 2014

AbstractThe analysis of several Ly49 genes has identified a tissue-specific promoter adjacent to the previously defined first exon. The current study reveals the presence of an additional Ly49 promoter (Pro-1) and two noncoding exons upstream of the previously defined promoter (Pro-2). DNA sequences homologous to Pro-1 are present 4–10 kb upstream of Pro-2 in all Ly49 genes examined, and Pro-1 transcripts were detected from the Ly49a, e, g, o, and v genes. Pro-1 activity can be detected in bone marrow, embryonic thymus, freshly isolated liver NK cells, and the murine LNK cell line, but it does not function in adult thymus, sorted NK-T cells, spleen NK cells, or the EL-4 T cell line, even though these cells express Ly49 proteins. Luciferase reporter assays identified a Pro-1 core promoter region that functions in the LNK cell line but not EL-4 cells. The novel promoter is not active in mature NK cells, suggesting that Pro-1 represents an early Ly49 promoter.
Kinetic Analysis of a Unique Direct Prothrombinase, fgl2, and Identification of a Serine Residue Critical for the Prothrombinase Activity
Authors: Chan Camie W. Y. , Chan Matthew W. C. , Liu Mingfeng , Fung Laisum , Cole Edward H. , Leibowitz Julian L. , Marsden Philip A. , Clark David A. , Levy Gary A. 
Published: April 2014

Abstract
fgl2 prothrombinase, by its ability to generate thrombin, has been shown to be pivotal to the pathogenesis of viral-induced hepatitis, cytokine-induced fetal loss syndrome, and xeno- and allograft rejection. In this study, the molecular basis of fgl2 prothrombinase activity was examined in detail. Purified fgl2 protein generated in a baculovirus expression system had no measurable prothrombinase activity, whereas the activity was restored when the purified protein was reconstituted into phosphatidyl-l-serine-containing vesicles. Reconstituted fgl2 catalyzed the cleavage of human prothrombin to thrombin with kinetics consistent with a first order reaction, with an apparent Vmax value of 6 mol/min/mol fgl2 and an apparent Km value for prothrombin of 8.3 μM. The catalytic activity was totally dependent on calcium, and factor Va (500 nM) enhanced the catalytic efficiency of fgl2 by increasing the apparent Vmax value to 3670 mol/min/mol fgl2 and decreasing the apparent Km value for prothrombin to 7.2 μM. By a combination of site-directed mutagenesis and production of truncated proteins, it was clearly shown that residue Ser89 was critical for the prothrombinase activity of fgl2. Furthermore, fgl2 prothrombinase activity was not inhibited by antithrombin III, soybean trypsin inhibitor, 4-aminobenzamidine, aprotinin, or phenylmethylsulfonyl fluoride, whereas diisopropylfluorophosphate completely abrogated the activity. In this work we provide direct evidence that fgl2 cleaves prothrombin to thrombin consistent with serine protease activity and requires calcium, phospholipids, and factor Va for its full activity.
Induction of Heat Shock Protein 47 Synthesis by TGF-β and IL-1β Via Enhancement of the Heat Shock Element Binding Activity of Heat Shock Transcription Factor 1
Authors: Sasaki Hiroyoshi , Sato Tsutomu , Yamauchi Naofumi , Okamoto Tetsuro , Kobayashi Daisuke , Iyama Satoshi , Kato Junji , Matsunaga Takuya , Takimoto Rishu , Takayama Tetsuji , Kogawa Katsuhisa , Watanabe Naoki , Niitsu Yoshiro 
Published: April 2014

Abstract
With most immunological reactions, tissue fibrosis, collagen overproduction caused by immune cytokines, is inevitably associated. Among the various immune cytokines, heat shock protein 47 (HSP47) is a procollagen-specific molecular chaperon and is essential for secretion of procollagen from cells. Induction of HSP47 by TGF-β has been previously reported in rat skeletal myoblasts and mouse osteoblasts, but not in human diploid fibroblasts. As for IL-1β, its effect on HSP47 has not been elucidated. In the present study, using human embryonic lung fibroblast cells, we first disclosed that both TGF-β and IL-1β induced HSP47 synthesis. We then revealed that the binding of the heat shock element (HSE) by heat shock transcription factor 1 (HSF1) was enhanced by both cytokines. We further demonstrated that trimer formation of HSF1, which is essential for its binding to HSE, was induced by these cytokines. The enhancement of HSP47 synthesis and their trimer formation of HSF1 were augmented by using a combination of both cytokines. Collectively, TGF- β and IL-1β were found to induce trimer formation of HSF1 which in turn bound to HSE of HSP47, resulting in the enhancement of HSP47 expression. Thus, HSP47 could well be a good candidate for molecular targeting in controlling tissue fibrosis, given that both principal fibrinogenetic cytokines (TGF-β, IL-1β) are commonly involved in its induction through HSF1 trimerization.
Antigenic Topology of Chlamydial PorB Protein and Identification of Targets for Immune Neutralization of Infectivity
Authors: Kawa Diane E. , Stephens Richard S. 
Published: April 2014

Abstract
The outer membrane protein PorB is a conserved chlamydial protein that functions as a porin and is capable of eliciting neutralizing Abs. A topological antigenic map was developed using overlapping synthetic peptides representing the Chlamydia trachomatis PorB sequence and polyclonal immune sera. To identify which antigenic determinants were surface accessible, monospecific antisera were raised to the PorB peptides and were used in dot-blot and ELISA-based absorption studies with viable chlamydial elementary bodies (EBs). The ability of the surface-accessible antigenic determinants to direct neutralizing Ab responses was investigated using standardized in vitro neutralization assays. Four major antigenic clusters corresponding to Phe34-Leu59 (B1-2 and B1-3), Asp112 -Glu145 (B2-3 and B2-4), Gly179-Ala225 (B3-2 to B3-4), and Val261-Asn305 (B4-4 to B5-2) were identified. Collectively, the EB absorption and dot-blot assays established that the immunoreactive PorB Ags were exposed on the surface of chlamydial EBs. Peptide-specific antisera raised to the surface-accessible Ags neutralized chlamydial infectivity and demonstrated cross-reactivity to synthetic peptides representing analogous C. pneumoniae PorB sequences. Furthermore, neutralization of chlamydial infectivity by C. trachomatis PorB antisera was inhibited by synthetic peptides representing the surface-exposed PorB antigenic determinants. These findings demonstrate that PorB Ags may be useful for development of chlamydial vaccines.
Costimulation of Host T Lymphocytes by a Trypanosomal trans-Sialidase: Involvement of CD43 Signaling
Authors: Todeschini Adriane R. , Nunes Marise P. , Pires Rachel S. , Lopes Marcela F. , Previato José O. , Mendonça-Previato Lúcia , DosReis George A. 
Published: April 2014

Abstract
Trans-sialidase is a membrane-bound and shed sialidase from Trypanosoma cruzi, the protozoan parasite responsible for Chagas disease. We investigated the role of soluble trans-sialidase on host CD4+ T cell activation. Trans-sialidase activated naive CD4+ T cells in vivo. Both enzymatically active and inactive recombinant trans-sialidases costimulated CD4+ T cell activation in vitro. Costimulation resulted in increased mitogen-activated protein kinase activation, proliferation, and cytokine synthesis. Furthermore, active and inactive trans-sialidases blocked activation-induced cell death in CD4+ T cells from T. cruzi-infected mice. By flow cytometry, inactive trans-sialidase bound the highly sialylated surface Ag CD43 on host CD4+ T cells. Both costimulatory and antiapoptotic effects of trans-sialidases required CD43 signaling. These results suggest that trans-sialidase family proteins are involved in exacerbated host T lymphocyte responses observed in T. cruzi infection.
Expansion of NK Cells with Reduction of Their Inhibitory Ly-49A, Ly-49C, and Ly-49G2 Receptor-Expressing Subsets in a Murine Helminth Infection: Contribution to Parasite Control
Authors: Korten Simone , Volkmann Lars , Saeftel Michael , Fischer Kerstin , Taniguchi Masaru , Fleischer Bernhard , Hoerauf Achim 
Published: April 2014

Abstract
Natural killer cell-associated direct cytotoxicity and cytokine production are crucial mechanisms for early innate host resistance against viruses, bacteria, or protozoa. The engagement of inhibitory NK cell receptors can influence host responses to viruses. However, these receptors have not been investigated to date in parasitic infections, and little is known about the role of NK cells in the defense against helminths. Therefore, we have correlated the frequencies of cells expressing the pan-NK marker DX5 and subsets bearing inhibitory Ly-49 receptors with worm survival and cytokine production during infection with Litomosoides sigmodontis in BALB/c mice (H2d), the only fully permissive model of filariasis. A marked influx of DX5+/CD3− NK cells and DX5+/CD3+ T cells into the pleural cavity, where the parasites were located, was observed. The frequency of pleural NK cells expressing the H2d-reactive inhibitory receptors Ly-49A, Ly-49C, or Ly-49G2 declined most strongly compared with spleen and blood. In the peripheral blood, longitudinal analysis revealed an early and stable reduction of Ly-49C+ and Ly-49G2+ NK cells, a subsequent significant increase of the entire NK cell and DX5+/CD3+ T cell populations, and a reduction in the Ly-49A+ subset. The in vivo depletion of NK cells strongly enhanced the worm load and influenced IL-4 and IL-5 plasma levels. These data demonstrate a new role for NK cells in the host defense against filariae and, for the first time, alterations of Ly-49 receptor-expressing NK cell subsets in a parasitic infection.
Critical Role of Signaling Through IL-1 Receptor for Development of Arthritis and Sepsis DuringStaphylococcus aureusInfection
Authors: Hultgren Olof H. , Svensson Lena , Tarkowski Andrej 
Published: April 2014

AbstractIL-1R-deficient mice (IL-1R−/−) and their wild-type controls (IL-1R+/+) were i.v. inoculated with 1 × 107 or 106 Staphylococcus aureus per mouse to mimic bacterial sepsis and septic arthritis. The disease outcome was severely worsened in the IL-1R−/− mice as compared with IL-1R+/+ mice. Indeed, 3 days after inoculation of 107 S. aureus per mouse 84% of IL-1R−/− mice displayed clinical signs of septicemia as compared with none of the IL-1R+/+ mice. On day 9 after inoculation with 106 S. aureus per mouse 75% of the IL-1R−/− mice were dead as compared with none of the IL-1R+/+ mice. Also, the number of staphylococci in circulation was 25- to 30-fold increased in IL-1R−/− mice as compared with IL-1R+/+ mice, the most probable reason for the outcome. The frequency and severity of septic arthritis were significantly increased in IL-1R−/− mice, as compared with IL-1R+/+ mice, following i.v. inoculation of staphylococci. This was probably due to an increased accumulation of bacteria in the joints of IL-1R−/− mice as compared with their wild-type controls. Interestingly, while serum levels of IL-18 in IL-1R−/− mice were significantly lower than in IL-1R+/+ mice 24 h after inoculation of S. aureus, both IL-18 and IL-1β were significantly increased in IL-1R−/− vs IL-1R+/+ mice 4 days after the bacterial inoculation. In conclusion, IL-1R signaling plays a crucial role in host protection during systemic S. aureus infection as seen by the fatal outcome of S. aureus sepsis and arthritis in IL-1R-deficient mice.
Complement C2 Receptor Inhibitor Trispanning and the β-Chain of C4 Share a Binding Site for Complement C2
Authors: Inal Jameel M. , Schifferli Jürg A. 
Published: April 2014

AbstractComplement C2 receptor inhibitor trispanning (CRIT) of the Schistosoma parasite binds human C2 via the C2a segment. The receptor in vivo functions as C2 decoy receptor by directly competing with C4b for binding to C2. As a result, CRIT is able to limit the extent of classical pathway (CP) C3 convertase formation. We report that the CRIT-extracellular domain 1 (ed1) peptide inhibits CP-mediated complement activation with an ICH50 of ∼0.1 μM, the C-terminal 11 aa of CRIT-ed1, named H17, even more effectively. The β-chain region F222–Y232 of C4 shares 55% identity and 73% similarity with H17. Peptides based on this region also inhibit CP in a dose-dependent manner. As further evidence of C2 binding we showed CRIT-ed1 peptides and homologous C4 β-chain peptides to inhibit complement in C2 hemolytic assays. We have predicted C4 β-c F222–Y232 as a C2 binding site which we have termed the CRIT-ed1 domain, and the sequence [F/H]EVKX4/5P as a consensus C2-binding sequence. Anti-CRIT-ed1 cross-reacts with the C4 β-chain and F222EVKITPGKPY232 appears to be the key epitope recognized by this Ab. Furthermore, anti-CRIT-ed1 was found to inhibit CP activation in a total hemolytic assay. We believe that Schistosoma CRIT-ed1, as well as C4 β-chain peptides based on the CRIT-ed1 domain, function as interface peptides. These peptides, based on C2-binding sequences in CRIT, or C4, competitively inhibit the binding of C2 to C4b and thus limit the activation of C. The C4 peptides, unlike CRIT-ed1, did not inhibit the cleavage of C2 by C1s.
Human C1qRp Is Identical with CD93 and the mNI-11 Antigen But Does Not Bind C1q
Authors: McGreal Eamon P. , Ikewaki Nobunao , Akatsu Hiroyasu , Morgan B. Paul , Gasque Philippe 
Published: April 2014

Abstract
It has been suggested that the human C1qRp is a receptor for the complement component C1q; however, there is no direct evidence for an interaction between C1q and C1qRp. In this study, we demonstrate that C1q does not show enhanced binding to C1qRp-transfected cells compared with control cells. Furthermore, a soluble recombinant C1qRp-Fc chimera failed to interact with immobilized C1q. The proposed role of C1qRp in the phagocytic response in vivo is also unsupported in that we demonstrate that this molecule is not expressed by macrophages in a variety of human tissues and the predominant site of expression is on endothelial cells. Studies on the rodent homolog of C1qRp, known as AA4, have suggested that this molecule may function as an intercellular adhesion molecule. Here we show that C1qRp is the Ag recognized by several previously described mAbs, mNI-11 and two anti-CD93 Abs (clones X2 and VIMD2b). Interestingly, mNI-11 (Fab′) has been shown to promote monocyte-monocyte and monocyte-endothelial cell adhesive interactions. We produced a recombinant C1qRp-Fc chimera containing the C-type lectin-like domain of C1qRp and found specific binding to vascular endothelial cells in sections of inflamed human tonsil, indicating the presence of a C1qRp ligand at this site. This interaction was Ca2+ independent and was not blocked by our anti-C1qRp mAb BIIG-4, but was blocked by the proadhesive mAb mNI-11. Collectively, these data indicate that C1qRp is not a receptor for C1q, and they support the emerging role of C1qRp (here renamed CD93) in functions relevant to intercellular adhesion.
Receptor-Mediated Monitoring of Tissue Well-Being Via Detection of Soluble Heparan Sulfate by Toll-Like Receptor 4
Authors: Johnson Geoffrey B. , Brunn Gregory J. , Kodaira Yuzo , Platt Jeffrey L. 
Published: April 2014

Abstract
Perturbations to the well-being of tissues in plants and invertebrates generate fragments of endogenous molecules that are recognized by innate immune receptors. Vertebrates have homologous receptors on specialized cells such as dendritic cells, but whether these receptors respond to fragments of endogenous molecules is not known. We tested the idea that Toll-like receptors on dendritic cells might recognize polysaccharide fragments of heparan sulfate proteoglycan. Dendritic cells were found to mature in response to heparan sulfate as measured by costimulatory protein expression, morphology, and T lymphocyte stimulation, but this maturation was absent when Toll-like receptor 4 was mutated or inhibited. These findings suggest that Toll-like receptors in vertebrates may monitor tissue well-being by recognizing fragments of endogenous macromolecules.
Two msbB Genes Encoding Maximal Acylation of Lipid A Are Required for Invasive Shigella flexneri to Mediate Inflammatory Rupture and Destruction of the Intestinal Epithelium
Authors: d’Hauteville Hélène , Khan Shahid , Maskell Duncan J. , Kussak Anders , Weintraub Andrej , Mathison John , Ulevitch Richard J. , Wuscher Nicole , Parsot Claude , Sansonetti Philippe J. 
Published: April 2014

Abstract
Shigella flexneri is a Gram-negative pathogen that invades and causes inflammatory destruction of the human colonic epithelium, thus leading to bloody diarrhea and dysentery. A type III secretion system that delivers effector proteins into target eukaryotic cells is largely responsible for cell and tissue invasion. However, the respective role of this invasive phenotype and of lipid A, the endotoxin of the Shigella LPS, in eliciting the inflammatory cascade that leads to rupture and destruction of the epithelial barrier, was unknown. We investigated whether genetic detoxification of lipid A would cause significant alteration in pathogenicity. We showed that S. flexneri has two functional msbB genes, one carried by the chromosome (msbB1) and the other by the virulence plasmid (msbB2), the products of which act in complement to produce full acyl-oxy-acylation of the myristate at the 3′ position of the lipid A glucosamine disaccharide. A mutant in which both the msbB1 and msbB2 genes have been inactivated was impaired in its capacity to cause TNF-α production by human monocytes and to cause rupture and inflammatory destruction of the epithelial barrier in the rabbit ligated intestinal loop model of shigellosis, indicating that lipid A plays a significant role in aggravating inflammation that eventually destroys the intestinal barrier. In addition, neutralization of TNF-α during invasion by the wild-type strain strongly impaired its ability to cause rupture and inflammatory destruction of the epithelial lining, thus indicating that TNF-α is a major effector of epithelial destruction by Shigella.
Regulation of Toll-Like Receptor 4 Expression in the Lung Following Hemorrhagic Shock and Lipopolysaccharide
Authors: Fan Jie , Kapus Andras , Marsden Philip A. , Li Yue Hua , Oreopoulos George , Marshall John C. , Frantz Stefan , Kelly Ralph A. , Medzhitov Ruslan , Rotstein Ori D. 
Published: April 2014

Abstract
The Toll-like receptor 4 (TLR4) has recently been shown to function as the major upstream sensor for LPS. In this study, a rodent model of lung injury following resuscitated hemorrhagic shock was used to examine the regulation of TLR4 gene and protein expression in vivo and in vitro. Intratracheal LPS alone induced a rapid reduction in whole lung TLR4 mRNA, an effect which is also observed in recovered alveolar macrophages. This effect appeared to be due to a lowering of TLR4 mRNA stability by ∼69%. By contrast, while shock/resuscitation alone had no effect on TLR4 mRNA levels, it markedly altered the response to LPS. Specifically, antecedent shock prevented the LPS-induced reduction in TLR4 mRNA levels. This reversal was explained by the ability of prior resuscitated shock both to prevent the destabilization of TLR4 mRNA by LPS and also to augment LPS-stimulated TLR4 gene transcription compared with LPS alone. Oxidant stress related to shock/resuscitation appeared to contribute to the regulation of TLR4 mRNA, because supplementation of the resuscitation fluid with the antioxidant N-acetylcysteine reversed the ability of shock/resuscitation to preserve TLR4 mRNA levels following LPS. TLR4 protein levels in whole lung mirrored the changes seen for TLR4 mRNA. Considered in aggregate, these data suggest that levels of tlr4 expression are controlled both transcriptionally as well as posttranscriptionally through altered mRNA stability and that antecedent shock/resuscitation, a form of global ischemia/reperfusion, might influence regulation of this gene.