bluuebunny/crossref_metadata_2025_split huggingface dataset:
Different Development of Myelin Basic Protein Agonist- and Antagonist-Specific Human TCR Transgenic T Cells in the Thymus and Periphery
Authors: Kawamura Kazuyuki , Yao Karen , Shukaliak-Quandt Jacqueline A. , Huh Jaebong , Baig Mirza , Quigley Laura , Ito Naoko , Necker Antje , McFarland Henry F. , Muraro Paolo A. , Martin Roland , Ito Kouichi 
Published: April 2014

Abstract
Myelin basic protein (MBP)-specific T cells are thought to play a role in the development of multiple sclerosis. MBP residues 111–129 compose an immunodominant epitope cluster restricted by HLA-DRB1*0401. The sequence of residues 111–129 of MBP (MBP111–129) differs in humans (MBP122:Arg) and mice (MBP122:Lys) at aa 122. We previously found that ∼50% of human MBP111–129 (MBP122:Arg)-specific T cell clones, including MS2-3C8 can proliferate in response to mouse MBP111–129 (MBP122:Lys). However, the other half of T cell clones, including HD4-1C2, cannot proliferate in response to MBP111–129 (MBP122:Lys). We found that MBP111–129 (MBP122:Lys) is an antagonist for HD4-1C2 TCR, therefore, MS2-3C8 and HD4-1C2 TCRs are agonist- and antagonist-specific TCRs in mice, respectively. Therefore, we examined the development of HD4-1C2 TCR and MS2-3C8 TCR transgenic (Tg) T cells in the thymus and periphery. We found that dual TCR expression exclusively facilitates the development of MBP111–129 TCR Tg T cells in the periphery of HD4-1C2 TCR/HLA-DRB1*0401 Tg mice although it is not required for their development in the thymus. We also found that MS2-3C8 TCR Tg CD8+ T cells develop along with MS2-3C8 TCR Tg CD4+ T cells, and that dual TCR expression was crucial for the development of MS2-3C8 TCR Tg CD4+ and CD8+ T cells in the thymus and periphery, respectively. These results suggest that thymic and peripheral development of MBP-specific T cells are different; however, dual TCR expression can facilitate their development.
Uncoupling the Roles of HLA-DRB1 and HLA-DRB5 Genes in Multiple Sclerosis
Authors: Caillier Stacy J. , Briggs Farren , Cree Bruce A. C. , Baranzini Sergio E. , Fernandez-Viña Marcelo , Ramsay Patricia P. , Khan Omar , Royal Walter , Hauser Stephen L. , Barcellos Lisa F. , Oksenberg Jorge R. 
Published: April 2014

Abstract
Genetic susceptibility to multiple sclerosis (MS) is associated with the MHC located on chromosome 6p21. This signal maps primarily to a 1-Mb region encompassing the HLA class II loci, and it segregates often with the HLA-DQB1*0602, -DQA1*0102, -DRB1*1501, -DRB5*0101 haplotype. However, the identification of the true predisposing gene or genes within the susceptibility haplotype has been handicapped by the strong linkage disequilibrium across the locus. African Americans have greater MHC haplotypic diversity and distinct patterns of linkage disequilibrium, which make this population particularly informative for fine mapping efforts. The purpose of this study was to establish the telomeric boundary of the HLA class II region affecting susceptibility to MS by assessing genetic association with the neighboring HLA-DRB5 gene as well as seven telomeric single nucleotide polymorphisms in a large, well-characterized African American dataset. Rare DRB5*null individuals were previously described in African populations. Although significant associations with both HLA-DRB1 and HLA-DRB5 loci were present, HLA-DRB1*1503 was associated with MS in the absence of HLA-DRB5, providing evidence for HLA-DRB1 as the primary susceptibility gene. Interestingly, the HLA-DRB5*null subjects appear to be at increased risk for developing secondary progressive MS. Thus, HLA-DRB5 attenuates MS severity, a finding consistent with HLA-DRB5’s proposed role as a modifier in experimental autoimmune encephalomyelitis. Additionally, conditional haplotype analysis revealed a susceptibility signal at the class III AGER locus independent of DRB1. The data underscore the power of the African American MS dataset to identify disease genes by association in a region of high linkage disequilibrium.
T Cell Responses to Whole SARS Coronavirus in Humans
Authors: Li Chris Ka-fai , Wu Hao , Yan Huiping , Ma Shiwu , Wang Lili , Zhang Mingxia , Tang Xiaoping , Temperton Nigel J. , Weiss Robin A. , Brenchley Jason M. , Douek Daniel C. , Mongkolsapaya Juthathip , Tran Bac-Hai , Lin Chen-lung Steve , Screaton Gavin R. , Hou Jin-lin , McMichael Andrew J. , Xu Xiao-Ning 
Published: April 2014

Abstract
Effective vaccines should confer long-term protection against future outbreaks of severe acute respiratory syndrome (SARS) caused by a novel zoonotic coronavirus (SARS-CoV) with unknown animal reservoirs. We conducted a cohort study examining multiple parameters of immune responses to SARS-CoV infection, aiming to identify the immune correlates of protection. We used a matrix of overlapping peptides spanning whole SARS-CoV proteome to determine T cell responses from 128 SARS convalescent samples by ex vivo IFN-γ ELISPOT assays. Approximately 50% of convalescent SARS patients were positive for T cell responses, and 90% possessed strongly neutralizing Abs. Fifty-five novel T cell epitopes were identified, with spike protein dominating total T cell responses. CD8+ T cell responses were more frequent and of a greater magnitude than CD4+ T cell responses (p &lt; 0.001). Polychromatic cytometry analysis indicated that the virus-specific T cells from the severe group tended to be a central memory phenotype (CD27+/CD45RO+) with a significantly higher frequency of polyfunctional CD4+ T cells producing IFN-γ, TNF-α, and IL-2, and CD8+ T cells producing IFN-γ, TNF-α, and CD107a (degranulation), as compared with the mild-moderate group. Strong T cell responses correlated significantly (p &lt; 0.05) with higher neutralizing Ab. The serum cytokine profile during acute infection indicated a significant elevation of innate immune responses. Increased Th2 cytokines were observed in patients with fatal infection. Our study provides a roadmap for the immunogenicity of SARS-CoV and types of immune responses that may be responsible for the virus clearance, and should serve as a benchmark for SARS-CoV vaccine design and evaluation.
Rap1 Activation Is Required for Fcγ Receptor-Dependent Phagocytosis
Authors: Chung Jooho , Serezani Carlos H. , Huang Steven K. , Stern Joel N. H. , Keskin Derin B. , Jagirdar Rajesh , Brock Thomas G. , Aronoff David M. , Peters-Golden Marc 
Published: April 2014

Abstract
Phagocytosis of IgG-opsonized microbes via the Fcγ receptor (FcγR) requires the precise coordination of a number of signaling molecules, including the low-molecular mass GTPases. Little is known about the Ras-family GTPase Rap1 in this process. We therefore investigated its importance in mediating FcγR-dependent phagocytosis in NR8383 rat alveolar macrophages. Pulldown of active Rap1 and fluorescence microscopic analysis of GFP-RalGDS (Ral guanine dissociation stimulator)-transfected macrophages revealed that Rap1 is indeed activated by FcγR crosslinking. Inhibition of Rap1 activity, both by Rap1GAP (GTPase-activating protein) expression and liposome-delivered blocking Ab, severely impaired the ability of cells to ingest IgG-opsonized targets. FcγR-induced Rap1 activation was found to be independent of both cAMP and Ca2+, suggesting a role for the second messenger-independent guanosine exchange factor, C3G. This was supported by the facts that 1) liposome-delivered blocking Ab against C3G inhibited both FcγR-dependent phagocytosis and Rap1 activation, and 2) both active Rap1GTP and C3G were found to translocate to the phagosome. Taken together, our data demonstrate a novel role for Rap1 and its exchange factor C3G in mediating FcγR-dependent phagocytosis.
The Clathrin-Mediated Endocytic Pathway Participates in dsRNA-Induced IFN-β Production
Authors: Itoh Kiyoharu , Watanabe Ayako , Funami Kenji , Seya Tsukasa , Matsumoto Misako 
Published: April 2014

Abstract
TLR3 and cytoplasmic RIG-I-like receptor (RLR) recognize virus-derived dsRNA and induce type I IFN production in a distinct manner. Human TLR3 localizes to the endosomal compartments in myeloid dendritic cells (mDCs), while it localizes to both the cell surface and interior in fibroblasts and epithelial cells. TLR3 signaling arises in the intracellular compartment in both cell types and requires endosomal maturation. The mechanisms by which extracellular dsRNA is delivered to the TLR3-containing organelle remain largely unknown. Among various synthetic dsRNAs, poly(I:C) is preferentially internalized and activates TLR3 in mDCs. In vitro transcribed dsRNAs hardly induce IFN-β production in mDCs. In this study, we demonstrate that the clathrin-dependent endocytic pathway mediates cell entry of poly(I:C) to induce IFN-β gene transcription. Furthermore, poly(I:C)-induced IFN-β production is inhibited by pretreatment of cells with B- and C-type oligodeoxynucleotides (ODNs) but not with TLR7/8 ligands. The binding and internalization of B-type ODNs by mDCs was reduced in the presence of poly(I:C), suggesting that poly(I:C) shares the uptake receptor with B- and C-type ODNs. Hence, foreign dsRNA is recognized by differently categorized receptors, cytoplasmic RIG-I-like receptor, membrane-bound TLR3 and cell-surface RNA capture. The endocytic pathway is critical for dsRNA-induced TLR3-mediated cell activation.
Inhibition of IFN-γ-Induced STAT1 Tyrosine Phosphorylation by Human CMV Is Mediated by SHP2
Authors: Baron Michel , Davignon Jean-Luc 
Published: April 2014

Abstract
Human CMV (HCMV) is a ubiquitous β-herpesvirus which has developed several mechanisms of escape from the immune system. IFN-γ-induced signaling relies on the integrity of the JAK/STAT pathway which is regulated by phosphorylation steps and leads to nuclear translocation of tyrosine-phosphorylated STAT1 (STAT1-P-Tyr), and its binding to IFN-γ activation site sequences of IFN-γ-inducible promoters. Activation of those promoters leads to the expression of genes involved in the immune response and in the antiviral effects of IFN-γ. Src homology region 2 domain-containing phosphatase 2 (SHP2) is a ubiquitous phosphatase involved in the regulation of IFN-γ-mediated tyrosine phosphorylation. Several mechanisms account for the inhibition IFN-γ signaling pathway by HCMV. In this study, we have identified a new mechanism that involved the inhibition of STAT1 tyrosine phosphorylation within 12–24 h postinfection. This defect was dependent on HCMV transcription. Consequences were impaired nuclear translocation of STAT1-P-Tyr, inhibition of IFN-γ activation site-STAT1 interaction, and inhibition of HLA-DR expression. Expression of indoleamine-2,3-dioxygenase which is involved in the antiviral effects of IFN-γ was also inhibited. Treatment of cells with sodium orthovanadate rescued STAT1 tyrosine phosphorylation, suggesting that a tyrosine phosphatase was involved in this inhibition. Coimmunoprecipitation of STAT1 and SHP2 was induced by HCMV infection, and SHP2 small interfering RNA restored the expression of STAT1-P-Tyr. Our data suggest that SHP2 activation induced by HCMV infection is responsible for the down-regulation of IFN-γ-induced STAT1 tyrosine phosphorylation.
Binding of Complement Inhibitor C4b-Binding Protein Contributes to Serum Resistance of Porphyromonas gingivalis
Authors: Potempa Michal , Potempa Jan , Okroj Marcin , Popadiak Katarzyna , Eick Sigrun , Nguyen Ky-Anh , Riesbeck Kristian , Blom Anna M. 
Published: April 2014

Abstract
The periodontal pathogen Porphyromonas gingivalis is highly resistant to the bactericidal activity of human complement, which is present in the gingival crevicular fluid at 70% of serum concentration. All thirteen clinical and laboratory P. gingivalis strains tested were able to capture the human complement inhibitor C4b-binding protein (C4BP), which may contribute to their serum resistance. Accordingly, in serum deficient of C4BP, it was found that significantly more terminal complement component C9 was deposited on P. gingivalis. Moreover, using purified proteins and various isogenic mutants, we found that the cysteine protease high molecular weight arginine-gingipain A (HRgpA) is a crucial C4BP ligand on the bacterial surface. Binding of C4BP to P. gingivalis appears to be localized to two binding sites: on the complement control protein 1 domain and complement control protein 6 and 7 domains of the α-chains. Furthermore, the bacterial binding of C4BP was found to increase with time of culture and a particularly strong binding was observed for large aggregates of bacteria that formed during culture on solid blood agar medium. Taken together, gingipains appear to be a very significant virulence factor not only destroying complement due to proteolytic degradation as we have shown previously, but was also inhibiting complement activation due to their ability to bind the complement inhibitor C4BP.
Interleukin-10 Promotes Mycobacterium tuberculosis Disease Progression in CBA/J Mice
Authors: Beamer Gillian L. , Flaherty David K. , Assogba Barnabe D. , Stromberg Paul , Gonzalez-Juarrero Mercedes , de Waal Malefyt Rene , Vesosky Bridget , Turner Joanne 
Published: April 2014

Abstract
IL-10 is a potent immunomodulatory cytokine that affects innate and acquired immune responses. The immunological consequences of IL-10 production during pulmonary tuberculosis (TB) are currently unknown, although IL-10 has been implicated in reactivation TB in humans and with TB disease in mice. Using Mycobacterium tuberculosis-susceptible CBA/J mice, we show that blocking the action of IL-10 in vivo during chronic infection stabilized the pulmonary bacterial load and improved survival. Furthermore, this beneficial outcome was highly associated with the recruitment of T cells to the lungs and enhanced T cell IFN-γ production. Our results indicate that IL-10 promotes TB disease progression. These findings have important diagnostic and/or therapeutic implications for the prevention of reactivation TB in humans.
Yersinia pestis Evades TLR4-dependent Induction of IL-12(p40)2 by Dendritic Cells and Subsequent Cell Migration
Authors: Robinson Richard T. , Khader Shabaana A. , Locksley Richard M. , Lien Egil , Smiley Stephen T. , Cooper Andrea M. 
Published: April 2014

Abstract
At the temperature of its flea vector (∼20–30°C), the causative agent of plague, Yersinia pestis, expresses a profile of genes distinct from those expressed in a mammalian host (37°C). When dendritic cells (DC) are exposed to Y. pestis grown at 26°C (Y. pestis-26°), they secrete copious amounts of IL-12p40 homodimer (IL-12(p40)2). In contrast, when DCs are exposed to Y. pestis grown at 37°C (Y. pestis-37°), they transcribe very little IL-12p40, which is secreted as IL-12p40 monomer (IL-12p40). Y. pestis-26° also induces migration of DCs to the homeostatic chemokine CCL19, whereas Y. pestis-37° does not; migratory DCs are positive for IL-12p40 transcription and secrete mostly IL-12(p40)2; DCs lacking IL-12p40 do not migrate. Expression of acyltransferase LpxL from Escherichia coli in Y. pestis-37° results in the production of a hexa-acylated lipid A, also seen in Y. pestis-26°, rather than tetra-acylated lipid A normally seen in Y. pestis-37°. The LpxL-expressing Y. pestis-37° promotes DC IL-12(p40)2 production and induction of DC migration. In addition, absence of TLR4 ablates production of IL-12(p40)2 in DC exposed to Y. pestis-26°. The data demonstrate the molecular pathway by which Y. pestis evades induction of early DC activation as measured by migration and IL-12(p40)2 production.
Evasion of Complement-Mediated Lysis and Complement C3 Deposition Are Regulated by Francisella tularensis Lipopolysaccharide O Antigen
Authors: Clay Corey D. , Soni Shilpa , Gunn John S. , Schlesinger Larry S. 
Published: April 2014

Abstract
The bacterium Francisella tularensis (Ft) is a potential weapon of bioterrorism when aerosolized. Macrophage infection is necessary for disease progression and efficient phagocytosis by human macrophages requires serum opsonization by complement. Microbial complement activation leads to surface deposition of a highly regulated protein complex resulting in opsonization or membrane lysis. The nature of complement component C3 deposition, i.e., C3b (opsonization and lysis) or C3bi (opsonization only) fragment deposition, is central to the outcome of activation. In this study, we examine the mechanisms of Ft resistance to complement-mediated lysis, C3 component deposition on the Ft surface, and complement activation. Upon incubation in fresh nonimmune human serum, Schu S4 (Ft subsp. tularensis), Fn (Ft subsp. novicida), and LVS (Ft subsp. holarctica live vaccine strain) were resistant to complement-mediated lysis, but LVSG and LVSR (LVS strains altered in surface carbohydrate structures) were susceptible. C3 deposition, however, occurred on all strains. Complement-susceptible strains had markedly increased C3 fragment deposition, including the persistent presence of C3b compared with C3bi, which indicates that C3b inactivation results in survival of complement-resistant strains. C1q, an essential component of the classical activation pathway, was necessary for lysis of complement-susceptible strains and optimal C3 deposition on all strains. Finally, use of Francisella LPS mutants confirmed O Ag as a major regulator of complement resistance. These data provide evidence that pathogenic Francisella activate complement, but are resistant to complement-mediated lysis in part due to limited C3 deposition, rapid conversion of surface-bound C3b to C3bi, and the presence of LPS O Ag.
CCR2 Mediates Homeostatic and Inflammatory Release of Gr1high Monocytes from the Bone Marrow, but Is Dispensable for Bladder Infiltration in Bacterial Urinary Tract Infection
Authors: Engel Daniel R. , Maurer Juliane , Tittel André P. , Weisheit Christina , Cavlar Taner , Schumak Beatrix , Limmer Andreas , van Rooijen Nico , Trautwein Christian , Tacke Frank , Kurts Christian 
Published: April 2014

Abstract
CCR2 is thought to recruit monocytes to sites of infection. Two subpopulations of murine blood monocytes differing in Gr1 and CCR2 expression have been described. The exact role of CCR2 in migration of CCR2lowGr1low and CCR2highGr1high monocytes into nonlymphoid tissue is controversial. In this study, we have addressed this question in a murine model of bacterial urinary tract infection. Only Gr1high monocytes were recruited into the infected bladder. CCR2 deficiency reduced their frequency in this organ, indicating a requirement of this chemokine receptor. Importantly, CCR2-deficient mice also showed reduced Gr1high monocyte numbers in the blood, but not in the bone marrow (BM), indicating that CCR2 acted at the step of monocyte release into the circulation. The same was found also in noninfected mice, indicating a further involvement of CCR2 in steady-state BM egress. An additional requirement of CCR2 in monocyte recruitment from the blood into the bladder was excluded by tracking particle-labeled endogenous monocytes and by adoptive transfer of BM-derived monocyte subsets. These findings demonstrate that CCR2 governs homeostatic and infection-triggered release of Gr1high monocytes from the BM into the blood but is dispensable for recruitment into a nonlymphoid tissue.
Adenylate Cyclase Toxin Subverts Phagocyte Function by RhoA Inhibition and Unproductive Ruffling
Authors: Kamanova Jana , Kofronova Olga , Masin Jiri , Genth Harald , Vojtova Jana , Linhartova Irena , Benada Oldrich , Just Ingo , Sebo Peter 
Published: April 2014

Abstract
Adenylate cyclase toxin (CyaA or ACT) is a key virulence factor of pathogenic Bordetellae. It penetrates phagocytes expressing the αMβ2 integrin (CD11b/CD18, Mac-1 or CR3) and paralyzes their bactericidal capacities by uncontrolled conversion of ATP into a key signaling molecule, cAMP. Using pull-down activity assays and transfections with mutant Rho family GTPases, we show that cAMP signaling of CyaA causes transient and selective inactivation of RhoA in mouse macrophages in the absence of detectable activation of Rac1, Rac2, or RhoG. This CyaA/cAMP-induced drop of RhoA activity yielded dephosphorylation of the actin filament severing protein cofilin and massive actin cytoskeleton rearrangements, which were paralleled by rapidly manifested macrophage ruffling and a rapid and unexpected loss of macropinocytic fluid phase uptake. As shown in this study for the first time, CyaA/cAMP signaling further caused a rapid and near-complete block of complement-mediated phagocytosis. Induction of unproductive membrane ruffling, hence, represents a novel sophisticated mechanism of down-modulation of bactericidal activities of macrophages and a new paradigm for action of bacterial toxins that hijack host cell signaling by manipulating cellular cAMP levels.
Airway Delivery of Soluble Mycobacterial Antigens Restores Protective Mucosal Immunity by Single Intramuscular Plasmid DNA Tuberculosis Vaccination: Role of Proinflammatory Signals in the Lung
Authors: Jeyanathan Mangalakumari , Mu Jingyu , Kugathasan Kapilan , Zhang Xizhong , Damjanovic Daniela , Small Cherrie , Divangahi Maziar , Petrof Basil J. , Hogaboam Cory M. , Xing Zhou 
Published: April 2014

Abstract
Protection by parenteral immunization with plasmid DNA vaccines against pulmonary tuberculosis (TB) is very modest. In this study, we have investigated the underlying mechanisms for the poor mucosal protective efficacy and the avenues and mechanisms to improve the efficacy of a single i.m. immunization with a monogenic plasmid DNA TB vaccine in a murine model. We show that i.m. DNA immunization fails to elicit accumulation of Ag-specific T cells in the airway lumen despite robust T cell responses in the spleen. Such systemically activated T cells cannot be rapidly mobilized into the airway lumen upon Mycobacterium tuberculosis exposure. However, airway deposition of low doses of soluble mycobacterial Ags in previously immunized mice effectively mobilizes the systemically activated T cells into the airway lumen. A fraction of such airway luminal T cells can persist in the airway lumen, undergo quick, robust expansion and activation and provide marked immune protection upon airway M. tuberculosis exposure. Airway mucosal deposition of soluble mycobacterial Ags was found to create a tissue microenvironment rich in proinflammatory molecules including chemokines and hence conducive to T cell recruitment. Thus, in vivo neutralization of MIP-1α or IFN-inducible protein-10 markedly inhibited the accumulation of Ag-specific T cells in the airway lumen. Our data suggest that immunoprotective efficacy on the mucosal surface by i.m. plasmid DNA immunization could be substantially improved by simple mucosal soluble Ag inoculation and restoration of mucosal luminal T cells. Our study holds implication for the future design of DNA vaccination strategies against intracellular infections.