bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of Complement in Cryoglobulin-Induced Immune Complex Glomerulonephritis
Authors: Trendelenburg Marten , Fossati-Jimack Liliane , Cortes-Hernandez Josefina , Turnberg Daniel , Lewis Margarita , Izui Shozo , Cook H. Terence , Botto Marina 
Published: April 2014

Abstract
Many forms of glomerulonephritis are triggered by Ab localization in the glomerulus, but the mechanisms by which this induces glomerular inflammation are not fully understood. In this study we investigated the role of complement in a mouse model of cryoglobulin-induced immune complex glomerulonephritis. Several complement-deficient mice on a C57BL/6 and BALB/c genetic background were used and compared with strain-matched, wild-type controls. Cryoglobulinemia was induced by i.p. injection of 6-19 hybridoma cells producing an IgG3 cryoglobulin with rheumatoid factor activity against IgG2a of allotype a present in BALB/c, but not C57BL/6, mice. Thus, the cryoprecipitate in C57BL/6 mice consisted of the IgG3 cryoglobulin only (type I cryoglobulinemia) compared with IgG3-IgG2a complexes in BALB/c (type II cryoglobulinemia). The survival of mice was not affected by complement deficiency. Glomerular influx of neutrophils was significantly less in C3-, factor B-, and C5-deficient mice compared with wild-type and C1q-deficient mice. It did not correlate with C3 deposition, but did correlate with the amount of C6 deposited. Deficiency of CD59a, the membrane inhibitor of the membrane attack complex, did not induce an increase in neutrophil infiltration, suggesting that the generation of C5a accounts for the effects observed. There was no apparent difference between cryoglobulinemia types I and II regarding the role of complement. Our results suggest that in this model of cryoglobulin-induced glomerulonephritis the neutrophil influx was mediated by C5 activation with the alternative pathway playing a prominent role in its cleavage. Thus, blocking C5 is a potential therapeutic strategy for preventing renal injury in cryoglobulinemia.
A Mimic of p21WAF1/CIP1 Ameliorates Murine Lupus
Authors: Goulvestre Claire , Chéreau Christiane , Nicco Carole , Mouthon Luc , Weill Bernard , Batteux Frédéric 
Published: April 2014

AbstractSystemic lupus erythematosus (SLE) is a progressive autoimmune disease characterized by the production of high levels of affinity-matured IgG autoantibodies to dsDNA and, possibly, visceral involvement. Pathogenic autoantibodies result from the activation and proliferation of autoreactive T and B lymphocytes stimulated by epitopes borne by nucleosomal histones. To inhibit the proliferation of autoreactive cells and abrogate the development of SLE, a novel tool, cell cycle inhibiting peptide therapy, was used. Thus, a peptidyl mimic of p21WAF1/CIP1 that inhibits the interaction between cyclin-dependent kinase 4 and type D cyclins abrogated the in vitro proliferative response of T cells to histones and T-independent and T-dependent proliferative responses of B cells. The WAF1/CIP1 mimic also abrogated the in vitro production of total and anti-dsDNA IgG Abs by B cells. Similarly, the p21WAF1/CIP1 construct inhibited the ex vivo T and B cell proliferative responses to histones and decreased the numbers of activated/memory B and T spleen cells. The alterations in the balance of spleen cell subsets resulted from proapoptotic effects of the p21WAF1/CIP1 construct on activated splenocytes. Finally, in vivo, four i.v. injections of the p21WAF1/CIP1 mimic were sufficient to inhibit the progression of the lupus-like syndrome in (NZB × NZW)F1 mice. The levels of anti-dsDNA IgG autoantibodies and the incidence and severity of renal involvement were lower in treated mice than in nontreated mice. Those observations open new avenues for the treatment of SLE and prompt us to evaluate the potential interest of peptidic therapy in human SLE.
Proteomic Scan for Tyrosinase Peptide Antigenic Pattern in Vitiligo and Melanoma: Role of Sequence Similarity and HLA-DR1 Affinity
Authors: Lucchese Alberta , Willers Jörg , Mittelman Abraham , Kanduc Darja , Dummer Reinhard 
Published: April 2014

Abstract
Immune responses contribute to the pathogenesis of vitiligo and target melanoma sometimes associated with vitiligo-like depigmentation in some melanoma patients. We analyzed the sera from patients with vitiligo and cutaneous melanoma for reactivity toward tyrosinase peptide sequences 1) endowed with low level of similarity to human proteome, and 2) potentially able to bind HLA-DR1 Ags. We report that the tyrosinase autoantigen was immunorecognized with the same molecular pattern by sera from vitiligo and melanoma patients. Five autoantigen peptides composed the immunodominant anti-tyrosinase response: aa95–104FMGFNCGNCK; aa175–182 LFVWMHYY; aa176–190FVWMHYYVSMDALLG; aa222–236IQKLTGDENFTIPYW, and aa233–247 IPYWDWRDAEKCDIC. All of the five antigenic peptides were characterized by being (or containing) a sequence with low similarity level to the self proteome. Sera from healthy subjects were responsive to aa95–104FMGFNCGNCK, aa222–236IQKLTGDENFTIPYW, and aa233–247 IPYWDWRDAEKCDIC, but did not react with the aa175–182LFVWMHYY and aa176–190FVWMHYYVSMDALLG peptide sequences containing the copper-binding His180 and the oculocutaneous albinism I-A variant position F176. Our results indicate a clear-cut link between peptide immunogenicity and low similarity level of the corresponding amino acid sequence, and are an example of a comparative analysis that might allow to comprehensively distinguish the epitopic peptide sequences within a disease from those associated to natural autoantibodies. In particular, these data, for the first time, delineate the linear B epitope pattern on tyrosinase autoantigen and provide definitive evidence of humoral immune responses against tyrosinase.
Cutting Edge: Murine CD59a Modulates Antiviral CD4+ T Cell Activity in a Complement-Independent Manner
Authors: Longhi M. Paula , Sivasankar Baalasubramanian , Omidvar Nader , Morgan B. Paul , Gallimore Awen 
Published: April 2014

AbstractCD59 blocks formation of the membrane attack complex of complement by inhibiting binding of C9 to the C5b-8 complex. To investigate a role for CD59 in promoting T cell responses, we compared T cell activation in CD59a-deficient (Cd59a−/−) and wild-type (WT) mice after in vitro stimulation and after infection with rVV. Virus-specific CD4+ T cell responses were significantly enhanced in Cd59a−/− mice compared with WT mice. Similarly, Cd59a−/− T cells responded more vigorously to in vitro stimulation with CD3-specific Abs compared with WT mice. This effect of CD59a on T cell proliferation was found to be complement-independent. Collectively, these results demonstrate that CD59a down-modulates CD4+ T cell activity in vitro and in vivo, thereby revealing another link between complement regulators and T cell activation.
Glucosamine Abrogates the Acute Phase of Experimental Autoimmune Encephalomyelitis by Induction of Th2 Response
Authors: Zhang Guang-Xian , Yu Shuo , Gran Bruno , Rostami Abdolmohamad 
Published: April 2014

Abstract
Glucosamine, a natural glucose derivative and an essential component of glycoproteins and proteoglycans, has been safely used to relieve osteoarthritis in humans. Recent studies have shown that glucosamine also possesses immunosuppressive properties and is effective in prolonging graft survival in mice. Whether this reagent is effective in human multiple sclerosis (MS), an inflammatory demyelination in the CNS, is not known. We thus investigated the therapeutic effect of glucosamine on experimental autoimmune encephalomyelitis (EAE), an animal model of MS. We demonstrated that oral, i.p., or i.v. administration of glucosamine significantly suppressed acute EAE, with reduced CNS inflammation and demyelination. A significant, albeit not strong, blockade of Th1 response and an up-regulation of Th2 cytokines (IL-5 and IL-10) are observed in the splenocytes of glucosamine-treated mice. Glucosamine also regulates IL-5 and IL-10 in vitro. As glucosamine is able to effectively suppress acute EAE, has low or absent toxicity, and has been safely used in humans orally, our study suggests a potential use for this drug alone or in combination with other disease-modifying immunotherapies to enhance their efficacy and reduce their doses in MS and possibly other autoimmune disorders. Furthermore, because glucosamine functions not simply as an immunosuppressant, but as a mild immunomodulator, administration of glucosamine provides a novel immunoregulatory approach for autoimmune disorders.
A Distal Regulatory Region Is Required for Constitutive and IFN-β-Induced Expression of Murine TLR9 Gene
Authors: Guo Zhu , Garg Sanjay , Hill Karen M. , Jayashankar Lakshmi , Mooney Myesha R. , Hoelscher Mary , Katz Jacqueline M. , Boss Jeremy M. , Sambhara Suryaprakash 
Published: April 2014

Abstract
TLR9 is critical for the recognition of unmethylated CpG DNA in innate immunity. Accumulating evidence suggests distinct patterns of TLR9 expression in various types of cells. However, the molecular mechanism of TLR9 expression has received little attention. In the present study, we demonstrate that transcription of murine TLR9 is induced by IFN-β in peritoneal macrophages and a murine macrophage cell line RAW264.7. TLR9 is regulated through two cis-acting regions, a distal regulatory region (DRR) and a proximal promoter region (PPR), which are separated by ∼2.3 kbp of DNA. Two IFN-stimulated response element/IFN regulatory factor-element (ISRE/IRF-E) sites, ISRE/IRF-E1 and ISRE/IRF-E2, at the DRR and one AP-1 site at the PPR are required for constitutive expression of TLR9, while only the ISRE/IRF-E1 motif is essential for IFN-β induction. In vivo genomic footprint assays revealed constitutive factor occupancy at the DRR and the PPR and an IFN-β-induced occupancy only at the DRR. IRF-2 constitutively binds to the two ISRE/IRF-E sites at the DRR, while IRF-1 and STAT1 are induced to bind to the two ISRE/IRF-E sites and the ISRE/IRF-E1, respectively, only after IFN-β treatment. AP-1 subunits, c-Jun and c-Fos, were responsible for the constitutive occupancy at the proximal region. Induction of TLR9 by IFN-β was absent in STAT1−/− macrophages, while the level of TLR9 induction was decreased in IRF-1−/− cells. This study illustrates the crucial roles for AP-1, IRF-1, IRF-2, and STAT1 in the regulation of murine TLR9 expression.
Stat1-Dependent Synergistic Activation of T-bet for IgG2a Production during Early Stage of B Cell Activation
Authors: Xu Weifeng , Zhang J. Jillian 
Published: April 2014

AbstractDuring the adaptive phase of an immune response, naive B cells receive multiple signals to become activated. Among them are the engagement of the B cell Ag receptor and stimulation by cytokines. Specifically for an anti-microbial response, the recognition of viral or bacterial Ags by the BCR and the stimulation of IFN-γ result in the predominant production of IgG2a. The T-bet protein has been shown to be required for class switching to IgG2a. In this report we further investigated the regulation of T-bet gene expression during the early stage of B cell activation. We show that there is a striking synergistic activation of T-bet in primary B cells when both the BCR and IFN-γ signaling pathways are activated. The synergistic activation of T-bet correlates with a 100% increase in the number of B cells that produce IgG2a. This transcription synergy on T-bet is transient in the first 24 h of B cell activation. Furthermore, we demonstrate that the synergistic activation of T-bet is dependent on Stat1 and that Stat1 is required for the IgG2a germline transcription and the production of IgG2a in response to the simultaneous signaling of BCR and IFN-γ. Finally, we show that Stat1 directly regulates the expression of T-bet by binding to the T-bet promoter. These results reveal the mechanism of regulation of T-bet expression and uncover a novel physiological function of Stat1 for B cell activation.
The Complex Mechanism of Antibody-Mediated Clearance of Bordetella from the Lungs Requires TLR4
Authors: Kirimanjeswara Girish S. , Mann Paul B. , Pilione Mylisa , Kennett Mary J. , Harvill Eric T. 
Published: April 2014

Abstract
Although the antibacterial effects of Abs are well studied in in vitro systems, the in vivo effects of Abs cannot always be accurately predicted. Complicated cross-talk between different effector functions of Abs and various arms of the immune system can affect their activities in vivo. Using the mouse respiratory pathogen Bordetella bronchiseptica, we examined the mechanisms of Ab-mediated clearance of bacteria from the respiratory tract. Interestingly, although TLR4 was not necessary for protective immunity following infection, it was required for rapid bacterial clearance in mice that were vaccinated or adoptively transferred Abs. TLR4 was important for the rapid recruitment of neutrophils that are necessary for Ab-mediated bacterial clearance via a mechanism that requires both FcγR and CR3. These data are consistent with a model in which TLR4-mediated inflammatory responses aid in the recruitment of neutrophils, which phagocytose Ab- and complement-opsonized bacteria via FcγRs and CR3. Although pattern recognition receptors are known to be involved in innate immunity and the generation of adaptive immunity, their contributions to specific adaptive immune functions should be considered in ongoing efforts to improve vaccine-induced protective immunity.
Staphylococcal Protein A Deletes B-1a and Marginal Zone B Lymphocytes Expressing Human Immunoglobulins: An Immune Evasion Mechanism
Authors: Viau Muriel , Longo Nancy S. , Lipsky Peter E. , Zouali Moncef 
Published: April 2014

AbstractProtein A (SpA) of Staphylococcus aureus is endowed with the capacity to interact with the H chain variable region (VH) of human Abs and to target &gt;40% of B lymphocytes. To investigate whether this property represents a virulence factor and to determine the in vivo consequences of the confrontation of SpA with B lymphocytes, we used transgenic mice expressing fully human Abs. We found that administration of soluble SpA reduces B-1a lymphocytes of the peritoneal cavity and marginal zone B lymphocytes of the spleen, resulting in a markedly deficient type 2 humoral response. Single-cell PCR analysis and sequencing of the Ab VH gene repertoire revealed a significant reduction of VH3+ marginal zone B cells. Since the two B lymphocyte subsets targeted are involved in innate immune functions, our data suggest that crippling of humoral immunity by S. aureus represents an immune evasion mechanism that may aggravate recurrent infections.
Signal Regulatory Proteins in the Immune System
Authors: van Beek Ellen M. , Cochrane Fiona , Barclay A. Neil , van den Berg Timo K. 
Published: April 2014

Abstract
Signal regulatory proteins (SIRPs) constitute a family of transmembrane glycoproteins with extracellular Ig-like domains. Several SIRP family members have thus far been identified on myeloid and other cells in man, mouse, rat, and cattle. In the present study, we provide a description of the SIRP multigene family, including a number of previously undescribed SIRP genes, based on the complete genome sequences of various mammalian and bird species. We discuss this information in the context of the known immunological properties of the individual SIRP family members. Our analysis reveals SIRPs as a diverse multigene family of immune receptors, which includes inhibitory SIRPα, activating SIRPβ, nonsignaling SIRPγ, and soluble SIRPδ members. For each species, there appears to be a single inhibitory SIRPα member that, upon interaction with the “self” ligand CD47, controls “homeostatic” innate immune effector functions, such as host cell phagocytosis. The activating SIRPβ proteins show considerable variability in structure and number across species and do not bind CD47. Thus the SIRP family is a rapidly evolving gene family with important roles in immune regulation.
Targeting LFA-1 and CD154 Suppresses the In Vivo Activation and Development of Cytolytic (CD4-Independent) CD8+ T Cells
Authors: Lunsford Keri E. , Koester Mitchel A. , Eiring Anna M. , Horne Phillip H. , Gao Donghong , Bumgardner Ginny L. 
Published: April 2014

Abstract
Short-term immunotherapy targeting both LFA-1 and CD40/CD154 costimulation produces synergistic effects such that long-term allograft survival is achieved in the majority of recipients. This immunotherapeutic strategy has been reported to induce the development of CD4+ regulatory T cells. In the current study, the mechanisms by which this immunotherapeutic strategy prevents CD8+ T cell-dependent hepatocyte rejection in CD4 knockout mice were examined. Combined blockade of LFA-1 and CD40/CD154 costimulation did not influence the overall number or composition of inflammatory cells infiltrating the liver where transplanted hepatocytes engraft. Expression of T cell activation markers CD43, CD69, and adhesion molecule CD103 by liver-infiltrating cells was suppressed in treated mice with long-term hepatocellular allograft survival compared to liver-infiltrating cells of untreated rejector mice. Short-term immunotherapy with anti-LFA-1 and anti-CD154 mAb also abrogated the in vivo development of alloreactive CD8+ cytotoxic T cell effectors. Treated mice with long-term hepatocyte allograft survival did not reject hepatocellular allografts despite adoptive transfer of naive CD8+ T cells. Unexpectedly, treated mice with long-term hepatocellular allograft survival demonstrated prominent donor-reactive delayed-type hypersensitivity responses, which were increased in comparison to untreated hepatocyte rejectors. Collectively, these findings support the conclusion that short-term immunotherapy with anti-LFA-1 and anti-CD154 mAbs induces long-term survival of hepatocellular allografts by interfering with CD8+ T cell activation and development of CTL effector function. In addition, these recipients with long-term hepatocellular allograft acceptance show evidence of immunoregulation which is not due to immune deletion or ignorance and is associated with early development of a novel CD8+CD25high cell population in the liver.
Increased Expression of Genes Linked to FcεRI Signaling and to Cytokine and Chemokine Production in Lyn-Deficient Mast Cells
Authors: Hernandez-Hansen Valerie , Bard Julie D. J. , Tarleton Christy A. , Wilder Julie A. , Lowell Clifford A. , Wilson Bridget S. , Oliver Janet M. 
Published: April 2014

Abstract
Cross-linking the high-affinity IgE receptor, FcεRI, on mast cells activates signaling pathways leading to the release of preformed inflammatory mediators and the production of cytokines and chemokines associated with allergic disorders. Bone marrow-derived mast cells (BMMCs) from Lyn-deficient (Lyn−/−) mice are hyperresponsive to FcεRI cross-linking with multivalent Ag. Previous studies linked the hyperresponsive phenotype in part to increased Fyn kinase activity and reduced SHIP phosphatase activity in the Lyn−/− BMMCs in comparison with wild-type (WT) cells. In this study, we compared gene expression profiles between resting and Ag-activated WT and Lyn−/− BMMCs to identify other factors that may contribute to the hyperresponsiveness of the Lyn−/− cells. Among genes implicated in the positive regulation of FcεRI signaling, mRNA for the tyrosine kinase, Fyn, and for several proteins contributing to calcium regulation are more up-regulated following Ag stimulation in Lyn−/− BMMCs than in WT BMMCs. Conversely, mRNA for the low-affinity IgG receptor (FcγRIIB), implicated in negative regulation of FcεRI-mediated signaling, is more down-regulated in Ag-stimulated Lyn−/− BMMCs than in WT BMMCs. Genes coding for proinflammatory cytokines and chemokines (IL-4, IL-6, IL-13, CSF, CCL1, CCL3, CCL5, CCL7, CCL9, and MIP1β)are all more highly expressed in Ag-stimulated Lyn−/− mast cells than in WT cells. These microarray data identify Lyn as a negative regulator in Ag-stimulated BMMCs of the expression of genes linked to FcεRI signaling and also to the response pathways that lead to allergy and asthma.
The Role of Low Molecular Weight Thiols in T Lymphocyte Proliferation and IL-2 Secretion
Authors: Hadzic Tanja , Li Ling , Cheng Ningli , Walsh Susan A. , Spitz Douglas R. , Knudson C. Michael 
Published: April 2014

Abstract
Glutathione (GSH) is an abundant intracellular tripeptide that has been implicated as an important regulator of T cell proliferation. The effect of pharmacological regulators of GSH and other thiols on murine T cell signaling, proliferation, and intracellular thiol levels was examined. l-Buthionine-S,R-sulfoximine (BSO), an inhibitor of GSH synthesis, markedly reduced GSH levels and blocked T cell proliferation without significant effect on cell viability. N-acetylcysteine markedly enhanced T cell proliferation without affecting GSH levels. Cotreatment of T cells with N-acetylcysteine and BSO failed to restore GSH levels, but completely restored the proliferative response. Both 2-ME and l-cysteine also reversed the BSO inhibition of T cell proliferation. Intracellular l-cysteine levels were reduced with BSO treatment and restored with cotreatment with NAC or l-cysteine. However, 2-ME completely reversed the BSO inhibition of proliferation without increasing intracellular cysteine levels. Therefore, neither GSH nor cysteine is singularly critical in limiting T cell proliferation. Reducing equivalents from free thiols were required because oxidation of the thiol moiety completely abolished the effect. Furthermore, BSO did not change the expression of surface activation markers, but effectively blocked IL-2 and IL-6 secretion. Importantly, exogenous IL-2 completely overcame BSO-induced block of T cell proliferation. These results demonstrate that T cell proliferation is regulated by thiol-sensitive pathway involving IL-2.
The Inhibitory Receptor IRp60 (CD300a) Is Expressed and Functional on Human Mast Cells
Authors: Bachelet Ido , Munitz Ariel , Moretta Alessandro , Moretta Lorenzo , Levi-Schaffer Francesca 
Published: April 2014

Abstract
Mast cell-mediated responses are likely to be regulated by the cross talk between activatory and inhibitory signals. We have screened human cord blood mast cells for recently characterized inhibitory receptors expressed on NK cells. We found that IRp60, an Ig superfamily member, is expressed on human mast cells. On NK cells, IRp60 cross-linking leads to the inhibition of cytotoxic activity vs target cells in vitro. IRp60 is constitutively expressed on mast cells but is down-regulated in vitro by the eosinophil proteins major basic protein and eosinophil-derived neurotoxin. An immune complex-mediated cross-linking of IRp60 led to inhibition of IgE-induced degranulation and stem cell factor-mediated survival via a mechanism involving tyrosine phosphorylation, phosphatase recruitment, and termination of cellular calcium influx. To evaluate the role of IRp60 in regulation of allergic responses in vivo, a murine model of allergic peritonitis was used in which the murine homolog of IRp60, LMIR1, was neutralized in BALB/c mice by mAbs. This neutralization led to a significantly augmented release of inflammatory mediators and eosinophilic infiltration. These data demonstrate a novel pathway for the regulation of human mast cell function and allergic responses, indicating IRp60 as a candidate target for future treatment of allergic and mast cell-associated diseases.