bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dissecting the Anti-Desmoglein Autoreactive B Cell Repertoire in Pemphigus Vulgaris Patients
Authors: Qian Ye , Diaz Luis A. , Ye Jian , Clarke Stephen H. 
Published: April 2014

AbstractPemphigus vulgaris (PV) encompasses two clinical phenotypes, one producing mucosal blisters and the other mucosal and skin lesions (mcPV). The mucosal blister-producing PV variant is characterized by autoantibodies against desmoglein (Dsg)3, whereas mucosal and skin lesion-producing PV is characterized by autoantibodies to Dsg3 and Dsg1. The present study was aimed at disclosing the diversity and clonality of the anti-Dsg3 response, as well as whether anti-Dsg3 B cells are Ag selected. Human-mouse heterohybridomas were generated by fusion of EBV-transformed or freshly isolated PBLs from six PV patients with mouse myeloma cells. A total of 73 anti-Dsg hybridomas (47 IgM and 26 IgG) were isolated. Over 90% are specific for both Dsg1 and Dsg3 indicating extensive cross-reactivity between these responses. VH gene segment use by IgM hybridomas is diverse, but is restricted among IgG hybridomas, where the majority uses one of two VH genes. VL gene segment use was diverse even among IgG hybridomas suggesting that the VL is less critical to defining desmoglein specificity. Additionally, the IgG hybridomas were extensively mutated and the distribution and nature of the mutations suggested that they had been Ag selected. We conclude that the potentially pathogenic IgG anti-Dsg response is restricted in VH use, is somatically mutated, and is Ag selected.
Down-Regulation of Human Complement Factor H Sensitizes Non-Small Cell Lung Cancer Cells to Complement Attack and Reduces In Vivo Tumor Growth
Authors: Ajona Daniel , Hsu Yi-Fan , Corrales Leticia , Montuenga Luis M. , Pio Ruben 
Published: April 2014

Abstract
Malignant cells are often resistant to complement activation through the enhanced expression of complement inhibitors. In this work, we examined the protective role of factor H, CD46, CD55, and CD59 in two non-small cell lung cancer cell lines, H1264 and A549, upon activation of the classical pathway of complement. Complement was activated with polyclonal Abs raised against each cell line. After blocking factor H activity with a neutralizing Ab, C3 deposition and C5a release were more efficient. Besides, a combined inhibition of factor H and CD59 significantly increased complement-mediated lysis. CD46 and CD55 did not show any effect in the control of complement activation. Factor H expression was knockdown on A549 cells using small interfering RNA. In vivo growth of factor H-deficient cells in athymic mice was significantly reduced. C3 immunocytochemistry on explanted xenografts showed an enhanced activation of complement in these cells. Besides, when mice were depleted of complement with cobra venom factor, growth was recovered, providing further evidence that complement was important in the reduction of in vivo growth. In conclusion, we show that expression of the complement inhibitor factor H by lung cancer cells can prevent complement activation and improve tumor development in vivo. This may have important consequences in the efficiency of complement-mediated immunotherapies.
Selective Role of NFATc3 in Positive Selection of Thymocytes
Authors: Canté-Barrett Kirsten , Winslow Monte M. , Crabtree Gerald R. 
Published: April 2014

Abstract
The four Ca2+-dependent NFATc proteins are both signal transducers and transcription factors that reside in the cytoplasm until dephosphorylation by calcineurin. Dephosphorylation exposes nuclear import sequences and sends NFATc proteins into the nucleus where they assemble with nuclear partners into NFAT transcription complexes. Recent genetic studies have indicated that calcineurin-NFAT signaling is a major determinant of vertebrate morphogenesis and development. Mice lacking calcineurin activity show a complete block in positive selection of CD4 and CD8 double-positive thymocytes, yet the role of the NFATc proteins in T cell development has been controversial. In this study, we address the requirement for NFATc3 in T cell development by generating NFATc3 conditional knockout mice. We show that specific deletion of NFATc3 in thymocytes causes a partial block at the double-negative stage 3 and also a partial block in positive selection. Furthermore, the defect does not become more pronounced when NFATc2 is also absent, consistent with the fact that NFATc2-null mice do not have a T cell developmental defect. Expression of a nuclear (and constitutively active) NFATc1 even at subphysiological levels can rescue the transition of double-negative to double-positive thymocytes in RAG-null mice, but is unable to rescue development of CD4 and CD8 single-positive cells. In addition to NFATc3, this suggests a role for NFATc1 in T cell development. Our studies indicate that the signals that direct positive selection likely use both NFATc1 and NFATc3 downstream of calcineurin.
IL-15 Is Required for Sustained Lymphopenia-Driven Proliferation and Accumulation of CD8 T Cells
Authors: Sandau Michelle M. , Winstead Colleen J. , Jameson Stephen C. 
Published: April 2014

Abstract
Naive T cells undergo slow homeostatic proliferation in response to T cell lymphopenia, which is also called lymphopenia-induced proliferation (LIP). IL-7 is critically required for this process, but previous studies suggested IL-15 was expendable for LIP of naive CD8 T cells. In contrast, we show that IL-15 is important for sustained CD8 T cell proliferation and accumulation in a lymphopenic setting, as revealed by truncated LIP in IL-15−/− hosts. At the same time, we find that IL-12 enhances LIP by acting directly on the CD8 T cells and independently of IL-15, suggesting distinct pathways by which cytokines can regulate homeostatic proliferation. Interestingly, the memory-phenotype CD8 T cell generated by LIP in IL-15−/− hosts are phenotypically distinct from the rare endogenous memory-phenotype cells found in IL-15−/− animals, suggesting these cells are generated by different means. These findings demonstrate that cytokine requirements for LIP change during the process itself, illustrating the need to identify factors that regulate successive stages of lymphopenia-driven proliferation.
β-Catenin Expression Enhances IL-7 Receptor Signaling in Thymocytes during Positive Selection
Authors: Yu Qing , Xu Mai , Sen Jyoti Misra 
Published: April 2014

Abstract
Differentiation of CD4+CD8+ double-positive thymocytes into CD8+ single-positive (SP) thymocytes is regulated by TCR and cytokine receptor signals. Previously, we have shown that expression of stabilized β-catenin, the major transcriptional cofactor of T cell factor, results in increase in both CD4SP and CD8SP thymocytes with a preferential effect on CD8SP thymocytes. In this report, using mice expressing stabilized β-catenin and mice with T cell specific deletion of β-catenin, we show that β-catenin expression augments IL-7Rα-chain expression and down-regulates suppressor of cytokine signaling-1 expression in thymocytes undergoing positive selection. Consequently, β-catenin expression augments IL-7R signaling in thymocytes during positive selection and promotes the development of CD8SP thymocytes.
TLR4 Polymorphisms Mediate Impaired Responses to Respiratory Syncytial Virus and Lipopolysaccharide
Authors: Tulic Meri K. , Hurrelbrink Robert J. , Prêle Cecilia M. , Laing Ingrid A. , Upham John W. , Le Souef Peter , Sly Peter D. , Holt Patrick G. 
Published: April 2014

Abstract
Severe bronchiolitis following respiratory syncytial virus (RSV) infection occurs in only a small subset of infected infants and the basis for variations in disease severity is not understood. Innate immune responses to RSV are mediated by TLR-4, and the 299Gly and 399Ile alleles of the TLR4 gene have been linked epidemiologically with increased severity of RSV disease in children. We hypothesized that cellular immune responses to RSV mediated by these variant forms of the receptor are defective relative to responses mediated via the common form of the receptor. Human bronchial epithelial cells were transfected with TLR4 constructs encoding the common TLR4 gene sequence (299Asp/399Thr), or the 299Gly or 399Ile alleles, and cytokine responses to in vitro RSV challenge were analyzed in the different transfected cells. Follow-up studies compared RSV-induced responses in PBMC from children expressing these same TLR4 genotypes. Human bronchial epithelial expressing 299Gly or 399Ile displayed normal levels of intracellular TLR4 but failed to efficiently translocate the receptor to the cell surface. This was associated with reduced NF-κB signaling post-TLR4 engagement, reduced production of IFNs, IL-8, IL-10, IL-12p35, IL-18, and CCL8, and the absence of acute-phase TNF-α. These findings were mirrored by blunted PBMC responses to RSV in children expressing the same TLR4 variants. Compromised first-line defense against RSV at the airway-epithelial surface of children expressing these TLR4 variants may thus confer increased susceptibility to severe infections with this virus.
Memory Generation and Maintenance of CD8+ T Cell Function during Viral Persistence
Authors: Cush Stephanie S. , Anderson Kathleen M. , Ravneberg David H. , Weslow-Schmidt Janet L. , Flaño Emilio 
Published: April 2014

Abstract
During infection with viruses that establish latency, the immune system needs to maintain lifelong control of the infectious agent in the presence of persistent Ag. By using a γ-herpesvirus (γHV) infection model, we demonstrate that a small number of virus-specific central-memory CD8+ T cells develop early during infection, and that virus-specific CD8+ T cells maintain functional and protective capacities during chronic infection despite low-level Ag persistence. During the primary immune response, we show generation of CD8+ memory T cell precursors expressing lymphoid homing molecules (CCR7, L-selectin) and homeostatic cytokine receptors (IL-7α, IL-2/IL-15β). During long-term persistent infection, central-memory cells constitute 20–50% of the virus-specific CD8+ T cell population and maintain the expression of L-selectin, CCR7, and IL-7R molecules. Functional analyses demonstrate that during viral persistence: 1) CD8+ T cells maintain TCR affinity for peptide/MHC complexes, 2) the functional avidity of CD8+ T cells measured as the capacity to produce IFN-γ is preserved intact, and 3) virus-specific CD8+ T cells have in vivo killing capacity. Next, we demonstrate that at 8 mo post-virus inoculation, long-term CD8+ T cells are capable of mediating a protective recall response against the establishment of γHV68 splenic latency. These observations provide evidence that functional CD8+ memory T cells can be generated and maintained during low-load γHV68 persistence.
Plasmodium falciparum Infection Causes Proinflammatory Priming of Human TLR Responses
Authors: McCall Matthew B. B. , Netea Mihai G. , Hermsen Cornelus C. , Jansen Trees , Jacobs Liesbeth , Golenbock Douglas , van der Ven André J. A. M. , Sauerwein Robert W. 
Published: April 2014

Abstract
TLRs are a major group of pattern recognition receptors that are crucial in initiating innate immune responses and are capable of recognizing Plasmodium ligands. We have investigated TLR responses during acute experimental P. falciparum (P.f.) infection in 15 malaria-naive volunteers. TLR-4 responses in whole blood ex vivo stimulations were characterized by significantly (p &lt; 0.01) up-regulated proinflammatory cytokine production during infection compared with baseline, whereas TLR-2/TLR-1 responses demonstrated increases in both proinflammatory and anti-inflammatory cytokine production. Responses through other TLRs were less obviously modified by malaria infection. The degree to which proinflammatory TLR responses were boosted early in infection was partially prognostic of clinical inflammatory parameters during the subsequent clinical course. Although simultaneous costimulation of human PBMC with P.f. lysate and specific TLR stimuli in vitro did not induce synergistic effects on cytokine synthesis, PBMC started to respond to subsequent TLR-4 and TLR-2 stimulation with significantly (p &lt; 0.05) increased TNF-α and reduced IL-10 production following increasing periods of preincubation with P.f. Ag. In contrast, preincubation with preparations derived from other parasitic, bacterial, and fungal pathogens strongly suppressed subsequent TLR responses. Taken together, P.f. primes human TLR responses toward a more proinflammatory cytokine profile both in vitro and in vivo, a characteristic exceptional among microorganisms.
IκB Kinase 2/β Deficiency Controls Expansion of Autoreactive T Cells and Suppresses Experimental Autoimmune Encephalomyelitis
Authors: Greve Bernhard , Weissert Robert , Hamdi Nada , Bettelli Estelle , Sobel Raymond A. , Coyle Anthony , Kuchroo Vijay K. , Rajewsky Klaus , Schmidt-Supprian Marc 
Published: April 2014

Abstract
The NF-κB family of transcription factors plays a pivotal role in T cell activation and survival during (auto) immune responses. IκB kinase 2/β (IKK2) is part of the IκB kinase complex, a central component of the intracellular signaling pathway mediating NF-κB activation. We studied the role of IKK2 in autoantigen-specific T cell activation and induction of autoimmune disease using mice that lack this kinase specifically in T cells (IKK2ΔT cell mice). We found highly impaired myelin-oligodendrocyte-glycoprotein (MOG)35–55-specific T cell activation in vitro and complete resistance to MOG35–55-induced experimental autoimmune encephalomyelitis (EAE) in IKK2ΔT cell C57BL/6 mice in vivo. By contrast, transgenic expression of a pathogenic MOG35–55-specific TCR (2D2 TCR) rendered IKK2ΔT cell mice susceptible to MOG35–55-induced EAE and restored in vitro MOG35–55-specific T cell responses, indicating an expansion defect in IKK2-deficient T cells. Treatment with the IKK2-inhibitory compound PS-1145 reduced MOG35–55-specific proliferation and cytokine production of 2D2 transgenic spleen cells in vitro and diminished clinical signs of EAE in vivo. Our data underscore the potential of therapeutic IKK inhibition in autoimmune diseases.
Synergism between NF-κB1/p50 and Notch2 during the Development of Marginal Zone B Lymphocytes
Authors: Moran Stewart T. , Cariappa Annaiah , Liu Haoyuan , Muir Beth , Sgroi Dennis , Boboila Cristian , Pillai Shiv 
Published: April 2014

Abstract
NF-κB1 and Notch2 are both required for the development of marginal zone (MZ) B cells. Analysis of B lymphocyte development in mice that are doubly heterozygous at the Notch2 and NF-κB1 loci revealed synergism between Notch2 and NF-κB1 during MZ B cell development. Two known transcriptional targets of the Notch pathway, Hes-5 and Deltex-1, were found to be preferentially expressed in MZ B cells and regulated by NF-κB1. These studies provide in vivo evidence for a genetic interaction between the Notch and NF-κB pathways.
Early Intrahepatic Accumulation of CD8+ T Cells Provides a Source of Effectors for Nonhepatic Immune Responses
Authors: Polakos Noelle K. , Klein Ingo , Richter Martin V. , Zaiss Dietmar M. , Giannandrea Matthew , Crispe Ian N. , Topham David J. 
Published: April 2014

Abstract
Interactions between the liver and CD8+ T cells can lead to tolerance, due in part to CD8+ T cell death. To test whether this was the case in an extrahepatic infection, we investigated the fate and effector capacity of intrahepatic CD8+ T cells during lung-restricted influenza infection in mice. Virus-specific T cells accumulated in livers without detectable intrahepatic presentation of viral Ags, and this accumulation was not restricted to the contraction phase, but was apparent as early as day 5. Intrahepatic influenza-specific cells were functionally similar to those recovered from the bronchioalveolar lavage, based on ex vivo cytokine production and specific target lysis. Both adoptive transfer of liver lymphocytes and orthotopic liver transplant of organs containing accumulated effector T cells revealed that activated CD8s from the liver were viable, expanded during reinfection, and generated a memory population that trafficked to lymphoid organs. Thus, intrahepatic CD8+ T cells re-enter circulation and generate functional memory, indicating that the liver does not uniformly incapacitate activated CD8+ T cells. Instead, it constitutes a substantial reservoir of usable Ag-specific effector CD8+ T cells involved in both acute and recall immune responses.
A Reduced Antigen Load In Vivo, Rather Than Weak Inflammation, Causes a Substantial Delay in CD8+ T Cell Priming againstMycobacterium bovis(Bacillus Calmette-Guérin)
Authors: Russell Marsha S. , Iskandar Monica , Mykytczuk Oksana L. , Nash John H. E. , Krishnan Lakshmi , Sad Subash 
Published: April 2014

AbstractRegardless of the dose of Ag, Ag presentation occurs rapidly within the first few days which results in rapid expansion of the CD8+ T cell response that peaks at day 7. However, we have previously shown that this rapid priming of CD8+ T cells is absent during infection of mice with Mycobacterium bovis (bacillus Calmette-Guérin (BCG)). In this study, we have evaluated the mechanisms responsible for the delayed CD8+ T cell priming. Because BCG replicates poorly and survives within phagosomes we considered whether 1) generation of reduced amounts of Ag or 2) weaker activation by pathogen-associated molecular patterns (PAMPs) during BCG infection is responsible for the delay in CD8+ T cell priming. Using rOVA-expressing bacteria, our results indicate that infection of mice with BCG-OVA generates greatly reduced levels of OVA, which are 70-fold lower in comparison to the levels generated during infection of mice with Listeria monocytogenes-expressing OVA. Furthermore, increasing the dose of OVA, but not PAMP signaling during BCG-OVA infection resulted in rapid Ag presentation and consequent expansion of the CD8+ T cell response, indicating that the generation of reduced Ag levels, not lack of PAMP-associated inflammation, was responsible for delayed priming of CD8+ T cells. There was a strong correlation between the relative timing of Ag presentation and the increase in the level of OVA in vivo. Taken together, these results reveal that some slowly replicating pathogens, such as mycobacteria, may facilitate their chronicity by generating reduced Ag levels which causes a substantial delay in the development of acquired immune responses.
A New Subset of Human Naive CD8+ T Cells Defined by Low Expression of IL-7Rα
Authors: Alves Nuno L. , van Leeuwen Ester M. M. , Remmerswaal Ester B. M. , Vrisekoop Nienke , Tesselaar Kiki , Roosnek Eddy , ten Berge Ineke J. M. , van Lier René A. W. 
Published: April 2014

Abstract
Concomitant with an increased number of memory-type cells, the amount of naive T cells steadily declines with age. Although the regulatory mechanisms behind this conversion are not fully understood, the suggestion is that both alterations in thymic output and homeostatic signals mold the naive T cell pool. In this study, we identify a new subset of circulating CD27highCD45RAhigh CD8+ T cells characterized by low IL-7Rα message and protein expression. Analysis of TCR repertoire and TCR excision circle content together with ex vivo recovery of IL-7Rα expression indicated that these cells should be placed into the naive T cell pool. Compared with conventional IL-7Rαhigh naive T cells, this subset displayed significantly lower levels of CD28 and higher levels of HLA-DR. Proliferative responses to anti-CD3/CD28 mAbs were indistinguishable from conventional naive T cells, but the responsiveness to IL-7 was limited. Strikingly, IL-7Rαlow naive T cells were particularly increased in circumstances of naive CD8+ T cells shortage, as in the elderly, in patients early after hemopoietic stem cell transplantation, and in HIV-infected individuals. As common γ chain cytokines induce rapid down-regulation of IL-7Rα, we propose that this new subset of naive T cells may encompass cells that have recently received homeostatic signals.
B Cell Receptor Cross-Talk: Exposure to Lipopolysaccharide Induces an Alternate Pathway for B Cell Receptor-Induced ERK Phosphorylation and NF-κB Activation
Authors: Dye John R. , Palvanov Arkadiy , Guo Benchang , Rothstein Thomas L. 
Published: April 2014

Abstract
BCR signaling in naive B cells depends on the function of signalosome mediators; however, prior engagement of CD40 or of IL-4R produces an alternate signaling pathway in which Bruton’s tyrosine kinase, PI3K, phospholipase Cγ2, and protein kinase Cβ are no longer required for BCR-induced downstream events. To explore the range of mediators capable of producing such an alternate pathway for BCR signaling, we examined the TLR4 agonist, LPS. B cell treatment with LPS at relatively low doses altered subsequent BCR signaling such that ERK phosphorylation and NF-κB activation occurred in a PI3K-independent manner. This effect of LPS extended to MEK phosphorylation and IκBα degradation, and it developed slowly over a period of 16–24 h. The involvement of TLRs is suggested by similar effects observed with a structurally distinct TLR agonist, PAM3CSK4 and by the need for MyD88 for induction of alternate BCR signaling by LPS. Thus, LPS-mediated TLR engagement produces an alternate pathway for BCR-triggered signal propagation that differs from the classical, signalosome-dependent pathway.
Aryl Hydrocarbon Receptor Activation during Influenza Virus Infection Unveils a Novel Pathway of IFN-γ Production by Phagocytic Cells
Authors: Neff-LaFord Haley , Teske Sabine , Bushnell Timothy P. , Lawrence B. Paige 
Published: April 2014

Abstract
The contribution of environmental factors is important as we consider reasons that underlie differential susceptibility to influenza virus. Aryl hydrocarbon receptor (AhR) activation by the pollutant dioxin during influenza virus infection decreases survival, which correlates with a 4-fold increase in pulmonary IFN-γ levels. We report here that the majority of IFN-γ-producing cells in the lung are neutrophils and macrophages not lymphocytes, and elevated IFN-γ is associated with increased pulmonary inducible NO synthase (iNOS) levels. Moreover, we show that even in the absence of dioxin, infection with influenza virus elicits IFN-γ production by B cells, γδ T cells, CD11c+ cells, macrophages and neutrophils, as well as CD3+ and NK1.1+ cells in the lung. Bone marrow chimeric mice reveal that AhR-mediated events external to hemopoietic cells direct dioxin-enhanced IFN-γ production. We also show that AhR-mediated increases in IFN-γ are dependent upon iNOS, but elevated iNOS in lung epithelial cells is not driven by AhR-dependent signals from bone marrow-derived cells. Thus, the lung contains important targets of AhR regulation, which likely influence a novel iNOS-mediated mechanism that controls IFN-γ production by phagocytic cells. This suggests that AhR activation changes the response of lung parenchymal cells, such that regulatory pathways in the lung are cued to respond inappropriately during infection. These findings also imply that environmental factors may contribute to differential susceptibility to influenza virus and other respiratory pathogens.