bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytochrome P4502D6193–212: A New Immunodominant Epitope and Target of Virus/Self Cross-Reactivity in Liver Kidney Microsomal Autoantibody Type 1-Positive Liver Disease
Authors: Kerkar Nanda , Choudhuri Kaushik , Ma Yun , Mahmoud Ayman , Bogdanos Dimitrios P. , Muratori Luigi , Bianchi Francesco , Williams Roger , Mieli-Vergani Giorgina , Vergani Diego 
Published: April 2014

Abstract
Cytochrome P4502D6 (CYP2D6), target of liver kidney microsomal autoantibody type 1 (LKM1), characterizes autoimmune hepatitis type 2 (AIH2) but is also found in patients with chronic hepatitis C virus (HCV) infection. To provide a complete linear epitope B cell map of CYP2D6, we tested peptides spanning the entire sequence of CYP2D6. In addition to confirming previously described antigenic sites, we identified four new epitopes (193–212, 238–257, 268–287, and 478–497). CYP2D6193–212 is immunodominant and was the target of 12 of 13 (93%) patients with AIH2 and 5 of 10 (50%) HCV/LKM1-positive patients. Because LKM1 is present in both AIH2 and a viral infection, we tested whether Abs to CYP2D6193–212 arise through cross-reactive immunity between virus and self. We identified a hexameric sequence “RLLDLA” sharing 5 of 6 aa with “RLLDLS” of HCV2985–2990 and all 6 aa with CMV130–135. Of 17 CYP2D6193–212-reactive sera, 11 (7 AIH and 4 HCV) reacted by ELISA with the HCV homologue, 8 (5 AIH and 3 HCV) with the CMV homologue, and 8 (5 AIH and 3 HCV) showed double reactivity. Autoantibody binding to CYP2D6193–212 was inhibited by preincubation with HCV2977–2996 or CMV121–140. Recombinant HCV-nonstructural protein 5 and CMV-UL98 proteins also inhibited Ab binding to CYP2D6193–212. Affinity-purified CYP2D6193–212-specific Ab inhibited the metabolic activity of CYP2D6. The demonstrated similarity and cross-reactivity between CYP2D6193–212 and two unrelated viruses suggests that multiple exposure to viruses mimicking self may represent an important pathway to the development of autoimmunity.
Induction of Antigen-Specific CTL Responses Using Antigens Conjugated to Short Peptide Vectors
Authors: Day Fiona H. , Zhang Yu , Clair Philippe , Grabstein Kenneth H. , Mazel Martine , Rees Anthony R. , Kaczorek Michel , Temsamani Jamal 
Published: April 2014

Abstract
Linear peptides (SynB vectors) with specific sequence motifs have been identified that are capable of enhancing the transport of a wide range of molecules into cells. These peptide vectors have been used to deliver exogenous peptides and protein Ags across the cell membrane and into the cytoplasm of cells. Specifically, in vitro analysis indicated that these SynB peptides enhanced the uptake of two 9-mer peptide Ags, NP147–155 and Mtb250–258 (T cell epitopes of influenza nucleoprotein and Mycobacterium tuberculosis, respectively) and the M. tuberculosis Ag Mtb8.4 protein, into K562 cells when covalently linked to the respective Ags. Furthermore, selected SynB vectors, when conjugated to these same Ags and used as immunogens, resulted in considerably enhanced Ag-specific CTL responses. Several SynB vectors were tested and resulted in varying levels of cellular uptake. The efficiency of uptake correlated with the ability of the SynB construct to deliver each epitope in vivo and induce specific CTL responses in mice. These data suggest that peptide vectors, such as SynB that transport target Ags across the cell membrane in a highly efficient manner, have significant potential for vaccine delivery.
Bordetella pertussisInfection in 2-Month-Old Infants Promotes Type 1 T Cell Responses
Authors: Mascart Françoise , Verscheure Virginie , Malfroot Anne , Hainaut Marc , Piérard Denis , Temerman Stéphane , Peltier Alexandra , Debrie Anne-Sophie , Levy Jack , Del Giudice Giuseppe , Locht Camille 
Published: April 2014

AbstractNeonatal immaturity of the immune system is currently believed to generally limit the induction of immune responses to vaccine Ags and to skew them toward type 2 responses. We demonstrated here that Bordetella pertussis infection in very young infants (median, 2 mo old) as well as the first administration of whole-cell pertussis vaccine induces B. pertussis Ag-specific IFN-γ secretion by the PBMC of these infants. IFN-γ was secreted by both CD4+ and CD8+ T lymphocytes, and the levels of Ag-induced IFN-γ secretion did not correlate with the age of the infants. Appearance of the specific Th-1 cell-mediated immunity was accompanied by a general shift of the cytokine secretion profile of these infants toward a stronger Th1 profile, as evidenced by the response to a polyclonal stimulation. We conclude that the immune system of 2-mo-old infants is developmentally mature enough to develop Th1 responses in vivo upon infection by B. pertussis or vaccination with whole-cell pertussis vaccines.
Cutting Edge: NK Cells Mediate IgG1-Dependent Hyperacute Rejection of Xenografts
Authors: Yin Dengping , Zeng Huasong , Ma Lianli , Shen Jikun , Xu Hui , Byrne Guerard W. , Chong Anita S. 
Published: April 2014

Abstract
Classic hyperacute rejection is dependent on the activation of the terminal components of complement. Recently, xenoantibodies with limited abilities to activate the classical pathway of complement in vitro have been implicated in the acute vascular rejection of xenografts. It is unclear how these Abs affect their pathogenic activities in vivo. In this study, we demonstrate the ability of an anti-Gal-α1,3Gal (Gal) IgG1, with modest complement-activating abilities in vitro, to induce xenograft rejection. This rejection was dependent on the activation of complement, on FcγR-mediated interactions, and on the presence of NK cells. Inhibition of any one of these factors resulted in the abrogation of IgG1-mediated rejection. In contrast, an anti-Gal IgG3 mAb induced classic, hyperacute rejection that was solely dependent on complement activation. Our observations implicate two types of IgG-mediated rejection; one that is dependent on complement activation, and a second that is uniquely dependent on complement, FcγR, and NK cells.
Rapid Development of T Cell Memory
Authors: Wong Phillip , Lara-Tejero María , Ploss Alexander , Leiner Ingrid , Pamer Eric G. 
Published: April 2014

Abstract
Prime-boost immunization is a promising strategy for inducing and amplifying pathogen- or tumor-specific memory CD8 T cell responses. Although expansion of CD8 T cell populations following the second Ag dose is integral to the prime-boost strategy, it remains unclear when, after priming, memory T cells become competent to proliferate. In this study, we show that Ag-specific CD8 T cells with the capacity to undergo extensive expansion are already present at the peak of the primary immune response in mice. These early memory T cells represent a small fraction of the primary immune response and, at early time points, their potential to proliferate is obscured by large effector T cell populations that rapidly clear Ag upon reimmunization. With sufficient Ag boosting, however, secondary expansion of these memory cells can be induced as early as 5–7 days following primary immunization. Importantly, both early and delayed boosting result in similar levels of protective immunity to subsequent pathogen challenge. Early commitment and differentiation of memory T cells during primary immunization suggest that a short duration between priming and boosting is feasible, providing potential logistic advantages for large-scale prime-boost vaccination of human populations.
Dexamethasone Suppresses Antigen-Induced Activation of Phosphatidylinositol 3-Kinase and Downstream Responses in Mast Cells
Authors: Andrade Marcus V. M. , Hiragun Takaaki , Beaven Michael A. 
Published: April 2014

Abstract
Dexamethasone and other glucocorticoids suppress FcεRI-mediated release of inflammatory mediators from mast cells. Suppression of cytokine production is attributed to repression of cytokine gene transcription but no mechanism has been described for the suppression of degranulation. We show that therapeutic concentrations of dexamethasone inhibit intermediate signaling events, in particular the activation of phosphatidylinositol (PI)3-kinase and downstream signaling events that lead to degranulation in rat basophilic leukemia 2H3 cells. This inhibitory action is mediated via the glucocorticoid receptor and is not apparent when cells are stimulated via Kit in a mouse bone marrow-derived mast cell line. The primary perturbation appears to be the failure of the regulatory p85 subunit of PI3-kinase to engage with the adaptor protein Grb2-associated binder 2 leading to suppression of phosphorylation of phospholipase Cγ2, the calcium signal, and degranulation. Suppression of PI3-kinase activation by dexamethasone may also contribute to reduced cytokine production because the PI3-kinase inhibitor LY294002, like dexamethasone, inhibits Ag-induced transcription of cytokine genes as well as degranulation.
IL-1β Suppresses Prolonged Akt Activation and Expression of E2F-1 and Cyclin A in Breast Cancer Cells
Authors: Shen Wen Hong , Jackson Steve T. , Broussard Suzanne R. , McCusker Robert H. , Strle Klemen , Freund Gregory G. , Johnson Rodney W. , Dantzer Robert , Kelley Keith W. 
Published: April 2014

Abstract
Cell cycle aberrations occurring at the G1/S checkpoint often lead to uncontrolled cell proliferation and tumor growth. We recently demonstrated that IL-1β inhibits insulin-like growth factor (IGF)-I-induced cell proliferation by preventing cells from entering the S phase of the cell cycle, leading to G0/G1 arrest. Notably, IL-1β suppresses the ability of the IGF-I receptor tyrosine kinase to phosphorylate its major docking protein, insulin receptor substrate-1, in MCF-7 breast carcinoma cells. In this study, we extend this juxtamembrane cross-talk between cytokine and growth factor receptors to downstream cell cycle machinery. IL-1β reduces the ability of IGF-I to activate Cdk2 and to induce E2F-1, cyclin A, and cyclin A-dependent phosphorylation of a retinoblastoma tumor suppressor substrate. Long-term activation of the phosphatidylinositol 3-kinase/Akt signaling pathway, but not the mammalian target of rapamycin or mitogen-activated protein kinase pathways, is required for IGF-I to hyperphosphorylate retinoblastoma and to cause accumulation of E2F-1 and cyclin A. In the absence of IGF-I to induce Akt activation and cell cycle progression, IL-1β has no effect. IL-1β induces p21Cip1/Waf1, which may contribute to its inhibition of IGF-I-activated Cdk2. Collectively, these data establish a novel mechanism by which prolonged Akt phosphorylation serves as a convergent target for both IGF-I and IL-1β; stimulation by growth factors such as IGF-I promotes G1-S phase progression, whereas IL-1β antagonizes IGF-I-induced Akt phosphorylation to induce cytostasis. In this manner, Akt serves as a critical bridge that links proximal receptor signaling events to more distal cell cycle machinery.
IL-12 Pretreatments Enhance IFN-α-Induced Janus Kinase-STAT Signaling and Potentiate the Antitumor Effects of IFN-α in a Murine Model of Malignant Melanoma
Authors: Lesinski Gregory B. , Badgwell Brian , Zimmerer Jason , Crespin Tim , Hu Yan , Abood Gerard , Carson William E. 
Published: April 2014

AbstractIFN-α 2b (IFN-α) has been used to treat patients with metastatic malignant melanoma and patients rendered disease-free via surgery but at high risk for recurrence. We hypothesized that IL-12 pretreatments would result in endogenous IFN-γ production, and that this, in turn, would up-regulate levels of Janus kinase-STAT signaling intermediates and lead to increased expression of genes regulated by IFN-α. Treatment of PBMCs with IL-12 stimulated a significant and dose-dependent production of IFN-γ. Pretreatment of PBMCs and tumor cells with IFN-γ-containing supernatants from IL-12-stimulated PBMCs led to up-regulation of STAT1, STAT2, and IFN regulatory factor 9 (IRF9) and potentiated IFN-α-induced STAT signaling within PBMCs and tumor cells. These effects were abrogated by neutralization of IFN-γ in the PBMC supernatants with an anti-IFN-γ Ab. Pretreatment of HT144 melanoma cells and PBMCs with IFN-γ or IFN-γ-containing supernatants enhanced the actions of IFN-α at the transcriptional level, as measured by real-time RT PCR analysis of the IFN-stimulated gene 15. Experiments in wild-type C57BL/6 and IFN-γ receptor knockout (B6.129S7-Ifngrtm1Agt) mice demonstrated that a regimen of IL-12 pretreatment, followed by IFN-α, could cure mice of i.p. B16F1 melanoma tumors (p &lt; 0.007), whereas mice treated with either agent alone or PBS succumbed to fatal tumor burden. However, this treatment regimen did not significantly prolong the survival of IFN-γ-deficient (B6.129S7-Ifngtm1Ts) mice compared with mice treated with IFN-α alone. These results suggest that the response to IFN-α immunotherapy can be significantly enhanced by IL-12 pretreatment, and this effect is dependent upon endogenous IFN-γ production and its actions on melanoma cells.
Chemokine Monokine Induced by IFN-γ/CXC Chemokine Ligand 9 Stimulates T Lymphocyte Proliferation and Effector Cytokine Production
Authors: Whiting David , Hsieh George , Yun James J. , Banerji Anamika , Yao William , Fishbein Michael C. , Belperio John , Strieter Robert M. , Bonavida Benjamin , Ardehali Abbas 
Published: April 2014

AbstractMonokine induced by IFN-γ (MIG; CXC chemokine ligand (CXCL)9) is important in T lymphocyte recruitment in organ transplantation. However, it is not known whether this chemokine, in addition to its chemotactic properties, exerts any effect on T lymphocyte effector functions. For in vivo studies, we used a previously characterized murine model of chronic rejection. The recipient mice were treated with anti-MIG/CXCL9 Ab; graft-infiltrating cells were analyzed for IFN-γ production. For in vitro studies, exogenous CXCR3 ligands were added to CD4 lymphocytes in MLRs, and the proliferative responses were measured. Separate experiments quantitated the number of IFN-γ-producing cells in MLRs by ELISPOT. Neutralization of MIG/CXCL9, in the in vivo model, resulted in significant reduction in the percentage of IFN-γ-producing graft-infiltrating T lymphocytes. In vitro experiments demonstrated that 1) exogenous MIG/CXCL9 stimulated CD4 lymphocyte proliferation in a MHC class II-mismatched MLR, 2) MIG/CXCL9 also increased the number of IFN-γ-producing CD4 lymphocytes in ELISPOT, 3) neutralization of MIG/CXCL9 in MLR reduced T lymphocyte proliferation, 4) IFN-γ-inducible protein 10/CXCL10 and IFN-inducible T cell α chemoattractant/CXCL11 had similar effects on T lymphocyte proliferation, 5) MIG/CXCL9 stimulated T lymphocyte proliferation in MHC class I- and total MHC-mismatched MLRs, 6) neutralization of CXCR3 reduced MIG/CXCL9-induced T lymphocyte proliferation and the number of IFN-γ-positive spots on ELISPOT, and 7) the proliferative effects of MIG/CXCL9 were mediated via an IL-2-independent pathway and were controlled by IFN-γ. This study demonstrates that MIG/CXCL9 stimulates T lymphocyte proliferation and effector cytokine production, in addition to its chemotactic effects. This novel observation expands our current understanding of MIG/CXCL9 biology beyond that of mediating T cell trafficking.
CTLA-4 Regulates Expansion and Differentiation of Th1 Cells Following Induction of Peripheral T Cell Tolerance
Authors: Eagar Todd N. , Turley Danielle M. , Padilla Josette , Karandikar Nitin J. , Tan Litjen , Bluestone Jeffrey A. , Miller Stephen D. 
Published: April 2014

Abstract
Intravenous treatment with Ag (peptide)-coupled, ethylene carbodiimide-fixed syngeneic splenocytes (Ag-SP) is a powerful method to induce anergy in vitro and peripheral T cell tolerance in vivo. In this study, we examined the effects of Ag-SP administration on T cell activity ex vivo and in vivo using OVA-specific DO11.10 TCR transgenic T cells. Although treatment with OVA323–339-SP resulted in a strong inhibition of peptide-specific T cell recall responses in vitro, examination of the immediate effects of Ag-SP treatment on T cells in vivo demonstrated that tolerogen injection resulted in rapid T cell activation and proliferation. Although there was an increase in the number of OVA-specific DO11.10 T cells detected in the lymphoid organs, these previously tolerized T cells were strongly inhibited in mounting proliferative or inflammatory responses upon rechallenge in vivo with peptide in CFA. This unresponsiveness was reversible by treatment with anti-CTLA-4 mAb. These results are consistent with the hypothesis that Ag-SP injection induces a state of T cell anergy that is maintained by CTLA-4 engagement.
Distinct Footprints of TCR Engagement with Highly Homologous Ligands
Authors: Santori Fabio R. , Holmberg Kaisa , Ostrov David , Gascoigne Nicholas R. J. , Vukmanović Stanislav 
Published: April 2014

Abstract
T cell receptor engagement promotes proliferation, differentiation, survival, or death of T lymphocytes. The affinity/avidity of the TCR ligand and the maturational stage of the T cell are thought to be principal determinants of the outcome of TCR engagement. We demonstrate in this study that the same mouse TCR preferentially uses distinct residues of homologous peptides presented by the MHC molecules to promote specific cellular responses. The preference for distinct TCR contacts depends on neither the affinity/avidity of TCR engagement (except in the most extreme ranges), nor the maturity of engaged T cells. Thus, different portions of the TCR ligand appear capable of biasing T cells toward specific biological responses. These findings explain differences in functional versatility of TCR ligands, as well as anomalies in the relationship between affinity/avidity of the TCR for the peptide/MHC and cellular responses of T cells.
Coupling In Silico and In Vitro Analysis of Peptide-MHC Binding: A Bioinformatic Approach Enabling Prediction of Superbinding Peptides and Anchorless Epitopes
Authors: Doytchinova Irini A. , Walshe Valerie A. , Jones Nicola A. , Gloster Simone E. , Borrow Persephone , Flower Darren R. 
Published: April 2014

Abstract
The ability to define and manipulate the interaction of peptides with MHC molecules has immense immunological utility, with applications in epitope identification, vaccine design, and immunomodulation. However, the methods currently available for prediction of peptide-MHC binding are far from ideal. We recently described the application of a bioinformatic prediction method based on quantitative structure-affinity relationship methods to peptide-MHC binding. In this study we demonstrate the predictivity and utility of this approach. We determined the binding affinities of a set of 90 nonamer peptides for the MHC class I allele HLA-A*0201 using an in-house, FACS-based, MHC stabilization assay, and from these data we derived an additive quantitative structure-affinity relationship model for peptide interaction with the HLA-A*0201 molecule. Using this model we then designed a series of high affinity HLA-A2-binding peptides. Experimental analysis revealed that all these peptides showed high binding affinities to the HLA-A*0201 molecule, significantly higher than the highest previously recorded. In addition, by the use of systematic substitution at principal anchor positions 2 and 9, we showed that high binding peptides are tolerant to a wide range of nonpreferred amino acids. Our results support a model in which the affinity of peptide binding to MHC is determined by the interactions of amino acids at multiple positions with the MHC molecule and may be enhanced by enthalpic cooperativity between these component interactions.
The CD40-Induced Signaling Pathway in Endothelial Cells Resulting in the Overexpression of Vascular Endothelial Growth Factor Involves Ras and Phosphatidylinositol 3-Kinase
Authors: Flaxenburg Jesse A. , Melter Michael , Lapchak Peter H. , Briscoe David M. , Pal Soumitro 
Published: April 2014

AbstractLigation of endothelial cell (EC) CD40 induces the expression of several proinflammatory cytokines as well as angiogenesis factors, including vascular endothelial growth factor (VEGF). Moreover, despite the reported importance of CD40 in cell-mediated immunity, little is known of the CD40-induced signaling pathways in EC. In this study, we have investigated the function of the Ras signaling pathway(s) for CD40-induced overexpression of VEGF. EC were transiently transfected with a full-length VEGF promoter-luciferase construct and a dominant-inhibitory mutant of Ras (Ras17N). Following transfection, ligation of CD40 with soluble CD40 ligand resulted in a significant increase in VEGF transcriptional activation, and the inhibitory mutant of Ras blocked this CD40-induced VEGF overexpression. Using EMSA and Western blot analysis, we demonstrated that CD40-dependent binding of nuclear protein(s) to the VEGF promoter and CD40-induced VEGF protein expression in EC were also inhibited by the Ras mutant. Immunoprecipitation studies revealed that ligation of CD40 on EC promoted an increased association of Ras with its effector molecules Raf, Rho, and phosphatidylinositol 3-kinase (PI3K). But, cotransfection of effector-loop mutants of Ras determined that only PI3K was functional for Ras-induced VEGF transcription. Also, wortmanin and a dominant-inhibitory mutant of PI3K inhibited CD40-induced overexpression of VEGF. Together these findings demonstrate that both Ras and PI3K are intermediaries in CD40-induced regulation of VEGF in EC. We believe our findings are of importance in several chronic inflammatory diseases, including atherosclerosis and allograft rejection associated with both CD40-CD40 ligand signaling as well as VEGF expression and function.
Characterization of a Peptide Inhibitor of Janus Kinase 2 That Mimics Suppressor of Cytokine Signaling 1 Function
Authors: Flowers Lawrence O. , Johnson Howard M. , Mujtaba Mustafa G. , Ellis Morgan R. , Haider S. Mohammed I. , Subramaniam Prem S. 
Published: April 2014

Abstract
Positive and negative regulation of cytokines such as IFN-γ are key to normal homeostatic function. Negative regulation of IFN-γ in cells occurs via proteins called suppressors of cytokine signaling (SOCS)1 and -3. SOCS-1 inhibits IFN-γ function by binding to the autophosphorylation site of the tyrosine kinase Janus kinase (JAK)2. We have developed a short 12-mer peptide, WLVFFVIFYFFR, that binds to the autophosphorylation site of JAK2, resulting in inhibition of its autophosphorylation as well as its phosphorylation of IFN-γ receptor subunit IFNGR-1. The JAK2 tyrosine kinase inhibitor peptide (Tkip) did not bind to or inhibit tyrosine autophosphorylation of vascular endothelial growth factor receptor or phosphorylation of a substrate peptide by the protooncogene tyrosine kinase c-src. Tkip also inhibited epidermal growth factor receptor autophosphorylation, consistent with the fact that epidermal growth factor receptor is regulated by SOCS-1 and SOCS-3, similar to JAK2. Although Tkip binds to unphosphorylated JAK2 autophosphorylation site peptide, it binds significantly better to tyrosine-1007 phosphorylated JAK2 autophosphorylation site peptide. SOCS-1 only recognizes the JAK2 site in its phosphorylated state. Thus, Tkip recognizes the JAK2 autophosphorylation site similar to SOCS-1, but not precisely the same way. Consistent with inhibition of JAK2, Tkip inhibited the ability of IFN-γ to induce an antiviral state as well as up-regulate MHC class I molecules on cells at a concentration of ∼10 μM. This is similar to the Kd of SOCS-3 for the erythropoietin receptor. These data represent a proof-of-concept demonstration of a peptide mimetic of SOCS-1 that regulates JAK2 tyrosine kinase function.