bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rosmarinic Acid Induces p56lck-Dependent Apoptosis in Jurkat and Peripheral T Cells via Mitochondrial Pathway Independent from Fas/Fas Ligand Interaction
Authors: Hur Yun-Gyoung , Yun Yungdae , Won Jonghwa 
Published: April 2014

Abstract
Apoptosis is one way of controlling immune responses, and a variety of immunosuppressive drugs suppress harmful immune responses by inducing apoptosis of lymphocytes. In this study we observed that rosmarinic acid, a secondary metabolite of herbal plants, induced apoptosis in an p56lck (Lck)-dependent manner; Lck+ Jurkat T cells undergo apoptosis in response to rosmarinic acid (RosA) treatment, whereas Lck− Jurkat subclone J.CaM1.6 cells do not. J.CaM1.6 cells with various Lck mutants indicated that Lck SH2 domain, but not Lck kinase activity, was required for RosA-induced apoptosis. RosA induced apoptosis in the absence of a TCR stimulus, and this was not prevented by interruption of the Fas/Fas ligand interaction. Instead, RosA-mediated apoptosis involved a mitochondrial pathway as indicated by cytochrome c release and the complete blockage of apoptosis by an inhibitor of mitochondrial membrane depolarization. Both caspase-3 and -8 were indispensable in RosA-induced apoptosis and work downstream of mitochondria and caspase-9 in the order of caspase-9/caspase-3/caspase-8. In freshly isolated human PBMC, RosA specifically induced apoptosis of Lck+ subsets such as T and NK cells, but not Lck-deficient cells, including B cells and monocytes. Moreover, RosA’s ability to kill T and NK cells was restricted to actively proliferating cells, but not to resting cells. In conclusion, Lck-dependent apoptotic activity may make RosA an attractive therapeutic tool for the treatment of diseases in which T cell apoptosis is beneficial.
The Susceptibility to Experimental Myasthenia Gravis of STAT6−/− and STAT4−/− BALB/c Mice Suggests a Pathogenic Role of Th1 Cells
Authors: Wang Wei , Ostlie Norma S. , Conti-Fine Bianca M. , Milani Monica 
Published: April 2014

Abstract
Autoantibodies to the muscle acetylcholine receptor (AChR) cause the symptoms of human and experimental myasthenia gravis (EMG). AChR-specific CD4+ T cells permit development of these diseases, but the role(s) of the Th1 and Th2 subsets is unclear. The STAT4 and STAT6 proteins, which mediate intracellular cytokine signaling, are important for differentiation of Th1 and Th2 cells, respectively. Wild-type (WT) BALB/c mice, which are prone to develop Th2 rather than Th1 responses to Ag, are resistant to EMG. We have examined the role of Th1 and Th2 cells in EMG using STAT4 (STAT4−/−)- or STAT6 (STAT6−/−)-deficient BALB/c mice. After AChR immunization, STAT6−/− mice were susceptible to EMG: they developed more serum anti-AChR Ab, and had more complement-fixing anti-AChR IgG2a and 2b and less IgG1 than WT or STAT4−/− mice. The susceptibility to EMG of STAT6−/− mice is most likely related to the Th1 cell-induced synthesis of anti-AChR Ab, which trigger complement-mediated destruction of the neuromuscular junction. CD4+ T cells of the STAT6−/− mice had proliferative responses to the AChR comparable to those of WT and STAT4−/− mice, and recognized similar AChR epitopes. STAT6−/− mice had abundant AChR-specific Th1 cells, which were nearly absent in WT and STAT4−/− mice. Spleen and lymph nodes from STAT6−/− mice contained cells that secreted IL-4 when cultured with AChR: these are most likely STAT6-independent cells, stimulated in a non-Ag-specific manner by the cytokines secreted by AChR-specific Th1 cells.
CD28 Signals in the Immature Immunological Synapse
Authors: Andres Pietro G. , Howland Kimberly C. , Dresnek Douglas , Edmondson Samuel , Abbas Abul K. , Krummel Matthew F. 
Published: April 2014

Abstract
T cell recognition of peptide-MHC complexes on APCs results in the aggregation of TCRs at a central supramolecular activation complex (c-SMAC) within a mature immunological synapse. T cells require a second “costimulatory” signal for activation, the most important of which, for naive T cells, is from CD28. However the time at which CD28-derived signals are induced relative to c-SMAC formation is not well understood. In this study, we have assessed the kinetics of CD28 localization and function relative to well-established aspects of c-SMAC formation. CD28 accumulates at the immature synapse alongside the TCR and is likewise enriched at the synapse at the onset of the calcium signal. In addition, using CD28 deficient or reconstituted murine cells in a single-cell recording approach shows that CD28 regulates this signal within seconds of a TCR-mediated rise in intracellular calcium levels. Finally, CD28 exerts effects on both the initiation and stabilization of the synapse in parallel with its effects on the downstream proliferation of T cells. Together, the data show that CD28 functions in the immunological synapse before the formation of the c-SMAC.
Up-Regulation of CD1d Expression Restores the Immunoregulatory Function of NKT Cells and Prevents Autoimmune Diabetes in Nonobese Diabetic Mice
Authors: Falcone Marika , Facciotti Federica , Ghidoli Nadia , Monti Paolo , Olivieri Stefano , Zaccagnino Luca , Bonifacio Ezio , Casorati Giulia , Sanvito Francesca , Sarvetnick Nora 
Published: April 2014

AbstractThe immunoregulatory function of NKT cells is crucial for prevention of autoimmunity. The prototypical NKT cell Ag α-galactosylceramide is not present in mammalian cells, and little is known about the mechanism responsible for NKT cell recruitment and activation. Up-regulation of CD1d, the NKT cell restriction molecule, expressed on mononuclear cells infiltrating the target organ, could represent the physiological trigger for NKT cells to self-contain T cell immunity and to prevent autoimmune disease. Recognition of CD1d, either by itself or bound to self-ligands (selfCD1d), could drive NKT cells toward an immunoregulatory phenotype. Hence, ineffective NKT cell-mediated immunoregulation in autoimmune-prone individuals including nonobese diabetic (NOD) mice could be related to defective signals that regulate CD1d expression at time and site of autoimmunity. To test this hypothesis, we transgenically overexpressed CD1d molecules under the control of the insulin promoter within the pancreatic islets of NOD mice (insCD1d). Recognition of overexpressed CD1d molecules rescued NKT cell immunoregulatory function and prevented autoimmune diabetes in insCD1d transgenic NOD mice. Protection from diabetes was associated with a biased IL-4-secreting cytokine phenotype of NKT cells and alteration of the cytokine microenvironment in the pancreatic lymph nodes of transgenic mice. The net effect was a reduced development of the autoimmune T cell repertoire. Our findings suggest that up-regulation of CD1d expression during inflammation is critical to maintain T cell homeostasis and to prevent autoimmunity.
Visualizing the Viral Burden: Phenotypic and Functional Alterations of T Cells and APCs during Persistent Infection
Authors: Homann Dirk , McGavern Dorian B. , Oldstone Michael B. A. 
Published: April 2014

Abstract
Persistent viral infections continue to present major public health problems. Failure to achieve virus control confronts the immune system with a chronic viral burden that may involve immune cells themselves and directly compromise the functionality of effector lymphocytes and APCs. In this study we use the lymphocytic choriomeningitis virus system for persistent viral infection of its natural murine host and use analytical techniques for direct ex vivo visualization of virus-infected immune cells. We report that virtually all cells of the immune system can be infected, but the distribution of the viral burden is differentially allocated to lymphocyte and APC subsets of defined phenotypes. Importantly, the profile of immune cell infection found in the blood is broadly representative for the pattern of cellular infection in most organs and is independent of the presence of Abs or complement. By direct comparison of virus-infected and uninfected cell subsets, we demonstrate that lymphocytic choriomeningitis virus-infected T cells show preferential activation, skewed cytokine profiles, and increased apoptosis. In contrast, increased activation of APCs is generalized and independent of the presence of viral Ag. Our data indicate that specific patterns of immune cell infection are associated with distinct forms of immunostimulatory and immunosuppressive alterations that may provide insights into autoimmune processes associated with infectious disease and offer clues for therapeutic interventions aimed at restoration of complete immunity.
Mast Cells, FcεRI, and IL-13 Are Required for Development of Airway Hyperresponsiveness after Aerosolized Allergen Exposure in the Absence of Adjuvant
Authors: Taube Christian , Wei Xudong , Swasey Christina H. , Joetham Anthony , Zarini Simona , Lively Tricia , Takeda Katsuyuki , Loader Joan , Miyahara Nobuaki , Kodama Taku , Shultz Lenny D. , Donaldson Debra D. , Hamelmann Eckard H. , Dakhama Azzeddine , Gelfand Erwin W. 
Published: April 2014

AbstractIn certain models of allergic airway disease, mast cells facilitate the development of inflammation and airway hyper-responsiveness (AHR). To define the role of the high affinity IgE receptor (FcεRI) in the development of AHR, mice with a disruption of the α subunit of the high affinity IgE receptor (FcεRI−/−) were exposed on 10 consecutive days to nebulized OVA. Forty-eight hours after the last nebulization, airway responsiveness was monitored by the contractile response of tracheal smooth muscle to electrical field stimulation (EFS). After the 10-day OVA challenge protocol, wild-type mice demonstrated increased responsiveness to EFS, whereas similarly challenged FcεRI−/− mice showed a low response to EFS, similar to nonexposed animals. Further, allergen-challenged FcεRI−/− mice showed less airway inflammation, goblet cell hyperplasia, and lower levels of IL-13 in lung homogenates compared with the controls. IL-13-deficient mice failed to develop an increased response to EFS or goblet cell hyperplasia after the 10-day OVA challenge. We transferred bone marrow-derived mast cells from wild-type mice to FcεRI−/− mice 1 day before initiating the challenge protocol. After the 10-day OVA challenge, recipient FcεRI−/− mice demonstrated EFS-induced responses similar to those of challenged wild-type mice. Transferred mast cells could be detected in tracheal preparations. These results show that FcεRI is important for the development of AHR after an aerosolized allergen sensitization protocol and that this effect is mediated through FcεRI on mast cells and production of IL-13 in the lung.
Generation and Regulation of Human Th1-Biased Immune Responses In Vivo: A Critical Role for IL-4 and IL-10
Authors: Skapenko Alla , Niedobitek Gerald U. , Kalden Joachim R. , Lipsky Peter E. , Schulze-Koops Hendrik 
Published: April 2014

AbstractTissue damage in many human autoimmune diseases is mediated by activated autoantigen-specific Th1 cells. Delineation of the regulatory mechanisms controlling a Th1-biased human immune reaction and its pathologic potential is, therefore, a critical step in the understanding of autoimmune diseases. In this study, we introduce a novel means to investigate human Th1-biased immune responses in vivo. Intraperitoneal injection of human mononuclear cells into immunodeficient mice generates a xenogeneic Th1-biased human immune response characterized by systemic inflammation and leukocytic infiltrates with a granuloma-like architecture in the liver, and the perigastrointestinal and perirenal fatty tissue. Th1 cell activation was dependent on the presence of APCs and could be blocked by cyclosporine. Importantly, neutralization of endogenously produced IL-4 and IL-10 markedly exaggerated the immune response, whereas exogenous IL-4 and IL-10 inhibited systemic Th1 immunity. Thus, the model described in this paper presents a useful means to analyze the regulation of human immune reactions in an in vivo situation. The results suggest that both IL-4 and IL-10 contribute to controlling the development of a human Th1-biased immune reaction.
Xenobiotic-Induced Loss of Tolerance in Rabbits to the Mitochondrial Autoantigen of Primary Biliary Cirrhosis Is Reversible
Authors: Amano Katsushi , Leung Patrick S. C. , Xu Qingchai , Marik Jan , Quan Chao , Kurth Mark J. , Nantz Michael H. , Ansari Aftab A. , Lam Kit S. , Zeniya Mikio , Coppel Ross L. , Gershwin M. Eric 
Published: April 2014

Abstract
Previous work has demonstrated that immunization of rabbits with the xenobiotic 6-bromohexanoate coupled to BSA breaks tolerance and induces autoantibodies to mitochondria in rabbits. Such immunized rabbits develop high-titer Abs to pyruvate dehydrogenase complex (PDC)-E2, the major autoantigen of primary biliary cirrhosis. In efforts to map the fine specificity of these autoantibodies, rabbits were immunized biweekly with 6-bromohexanoate-BSA and screened for reactivity using a unique xenobiotic-peptide-agarose microarray platform with an emphasis on identifying potential structures that mimic the molecular image formed by the association of lipoic acid with the immunodominant PDC-E2 peptide. Essentially, a total of 23 xenobiotics and lipoic acid were coupled to the 12-mer peptide backbones, PDC, a mutant PDC, and albumin. As expected, we succeeded in breaking tolerance using this small organic molecule coupled to BSA. However, unlike multiple experimental methods of breaking tolerance, we report in this study that, following continued immunization, the rabbits recover tolerance. With repeated immunization, the response to the rPDC-E2 protein increased with a gradual reduction in autoantibodies against the lipoic acid-peptide, i.e., the primary tolerance-breaking autoantigen. Detailed analysis of this system may provide strategies on how to restore tolerance in patients with autoimmune disease.
Requirement for Donor and Recipient CD40 Expression in Cardiac Allograft Rejection: Induction of Th1 Responses and Influence of Donor-Derived Dendritic Cells
Authors: Nathan Meera J. , Mold Jeffrey E. , Wood Sherri C. , Csencsits Keri , Lu Guanyi , Eichwald Ernst J. , Bishop D. Keith 
Published: April 2014

Abstract
Costimulation through the CD40-CD40 ligand (CD40L) pathway is critical to allograft rejection, in that anti-CD40L mAb therapy prolongs allograft survival. However, the majority of studies exploring CD40-CD40L interactions have targeted CD40L. Less is known about the requirement for donor- and/or host-derived CD40 during rejection. This study assessed the relative contributions of donor and recipient CD40 expression to the rejection process. As the effectiveness of costimulatory blockade may be mouse strain dependent, this study explored the requirement for donor and recipient CD40 expression in BALB/c and C57BL/6 mice. Wild-type (WT) and CD40−/− BALB/c recipients readily rejected WT and CD40−/− C57BL/6 allografts, and rejection was associated with a prominent Th1 response. In contrast, CD40−/− C57BL/6 recipients failed to reject WT or CD40−/− BALB/c allografts and did not mount Th1 or Th2 responses. However, injection of donor CD40−/− dendritic cells induced both Th1 and Th2 responses and allograft rejection in CD40−/− C57BL/6 recipients. Finally, WT C57BL/6 mice rejected CD40−/− allografts, but this rejection response was associated with muted Th1 responses. These findings demonstrate that 1) CD40 expression by the recipient or the graft may impact on the immune response following transplantation; 2) the requirement for CD40 is influenced by the mouse strain; and 3) the requirement for CD40 in rejection may be bypassed by donor DC. Further, as CD40 is not required for rejection in BALB/c recipients, but anti-CD40L mAb prolongs graft survival in these mice, these results suggest that anti-CD40L therapy functions at a level beyond disruption of CD40-CD40L interactions.
Nucleosomes Are Exposed at the Cell Surface in Apoptosis
Authors: Radic Marko , Marion Tony , Monestier Marc 
Published: April 2014

AbstractApoptotic cells are considered the source of DNA, histones, and nucleoprotein complexes that drive the production of autoantibodies in systemic lupus erythematosus. However, the role of apoptotic cells in the activation of the immune system is not clear. To explore interactions that may initiate or sustain the production of anti-nuclear autoantibodies, we characterized the binding of a large panel of monoclonal autoantibodies to apoptotic cells. Autoantibodies to DNA, individual core histones, histone-DNA complexes, or the native nucleosome core particle revealed a consistent and specific binding pattern in confocal microscopy. Immunoreactive epitopes were detected in the cytoplasm and accumulated along the surface of the fragmenting nucleus in a caspase-dependent manner. Ag-Ab complexes on nuclear fragments that had emerged from the plasma membrane were accessible to anti-isotype-reactive microparticles. Moreover, autoantibodies specific for the nucleosome core or its molecular components selectively precipitated a complex of core histones and DNA from the cytosol at 4 h after induction of apoptosis. These observations identify distinct steps in the release of nucleosomes from the nucleus and their exposure at the cell surface. Furthermore, the results indicate a direct role for nucleosomes in the execution of apoptosis, clearance of apoptotic cells, and regulation of anti-nuclear autoantibody production.
Expression of L-Selectin, but Not CD44, Is Required for Early Neutrophil Extravasation in Antigen-Induced Arthritis
Authors: Szántó Sándor , Gál István , Gonda Andrea , Glant Tibor T. , Mikecz Katalin 
Published: April 2014

AbstractL (leukocyte)-selectin (CD62L) and CD44 are major adhesion receptors that support the rolling of leukocytes on endothelium, the first step of leukocyte entry into inflamed tissue. The specific contribution of L-selectin or CD44 to the regulation of cell traffic to joints in arthritis has not been investigated. We used CD44-deficient, L-selectin-deficient, and CD44/L-selectin double knockout mice to determine the requirement for these receptors for inflammatory cell recruitment during Ag-induced arthritis. Intraperitoneal immunization resulted in similar activation status and Ag-specific responses in wild-type and gene-targeted mice. However, extravasation of neutrophil granulocytes, but not the emigration of T cells, into the knee joints after intra-articular Ag injection was significantly delayed in L-selectin-deficient and double knockout mice. Intravital videomicroscopy on the synovial microcirculation revealed enhanced leukocyte rolling and diminished adherence in mice lacking either CD44 or L-selectin, but CD44 deficiency had no significant effect on the recruitment of L-selectin-null cells. Compared with wild-type leukocytes, expression of L-selectin was down-regulated in CD44-deficient cells in the spleen, peripheral blood, and inflamed joints, suggesting that reduced expression of L-selectin, rather than the lack of CD44, could be responsible for the delayed influx of granulocytes into the joints of CD44-deficient mice. In conclusion, there is a greater requirement for L-selectin than for CD44 for neutrophil extravasation during the early phase of Ag-induced arthritis.
Evidence That the Long Murine Terminal Deoxynucleotidyltransferase Isoform Plays No Role in the Control of V(D)J Junctional Diversity
Authors: Doyen Noëlle , Boulé Jean-Baptiste , Rougeon François , Papanicolaou Catherine 
Published: April 2014

Abstract
Two TdT isoforms have been found in the mouse. The short isoform is known to add N regions to gene segment junctions during V(D)J recombination, but the role of the long (TdTL) isoform is controversial. We have shown that TdTL, although endowed with terminal transferase activity, is thermally unstable and unable to add N regions in vivo. In this study, we demonstrate that TdTL is devoid of 3′-5′ exonuclease activity, and provide an analysis of nucleotide deletion and addition patterns in large series of V(D)J coding joins, arguing against a role of TdTL in the control of junctional diversity in Igs and TCRs.
Characterization of the Human Ig Heavy Chain Antigen Binding Complementarity Determining Region 3 Using a Newly Developed Software Algorithm, JOINSOLVER
Authors: Souto-Carneiro M. Margarida , Longo Nancy S. , Russ Daniel E. , Sun Hong-wei , Lipsky Peter E. 
Published: April 2014

AbstractWe analyzed 77 nonproductive and 574 productive human VHDJH rearrangements with a newly developed program, JOINSOLVER. In the productive repertoire, the H chain complementarity determining region 3 (CDR3H) was significantly shorter (46.7 ± 0.5 nucleotides) than in the nonproductive repertoire (53.8 ± 1.9 nucleotides) because of the tendency to select rearrangements with less TdT activity and shorter D segments. Using criteria established by Monte Carlo simulations, D segments could be identified in 71.4% of nonproductive and 64.4% of productive rearrangements, with a mean of 17.6 ± 0.7 and 14.6 ± 0.2 retained germline nucleotides, respectively. Eight of 27 D segments were used more frequently than expected in the nonproductive repertoire, whereas 3 D segments were positively selected and 3 were negatively selected, indicating that both molecular mechanisms and selection biased the D segment usage. There was no bias for D segment reading frame (RF) use in the nonproductive repertoire, whereas negative selection of the RFs encoding stop codons and positive selection of RF2 that frequently encodes hydrophilic amino acids were noted in the productive repertoire. Except for serine, there was no consistent selection or expression of hydrophilic amino acids. A bias toward the pairing of 5′ D segments with 3′ JH segments was observed in the nonproductive but not the productive repertoire, whereas VH usage was random. Rearrangements using inverted D segments, DIR family segments, chromosome 15 D segments and multiple D segments were found infrequently. Analysis of the human CDR3H with JOINSOLVER has provided comprehensive information on the influences that shape this important Ag binding region of VH chains.
Massive Number of Antigen-Specific CD4 T Cells during Vaccination with Live Attenuated Salmonella Causes Interclonal Competition
Authors: Srinivasan Aparna , Foley Joseph , McSorley Stephen J. 
Published: April 2014

Abstract
The clonal burst size of CD4 T cells is predicted to be less than that of CD8 T cells. In this study, we demonstrate that massive numbers of Ag-specific CD4 T cells respond during vaccination of mice with live attenuated Salmonella, reaching a peak frequency of ∼50% of CD4 T cells. Salmonella-specific T cells persisted at high frequency for several weeks and could be detected in the memory population for months after infection. Surprisingly, the expansion of endogenous Salmonella-specific CD4 T cells prevented the persistence of adoptively transferred Salmonella-specific T cells in vivo, demonstrating interclonal competition for access to the memory compartment.