bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective Localization of Recognition Complexes for Leukotriene B4 and Formyl-Met-Leu-Phe within Lipid Raft Microdomains of Human Polymorphonuclear Neutrophils
Authors: Sitrin Robert G. , Emery Sarah L. , Sassanella Timothy M. , Blackwood R. Alexander , Petty Howard R. 
Published: April 2014

Abstract
Neutrophilic polymorphonuclear leukocytes contain glycosphingolipid- and cholesterol-enriched lipid raft microdomains within the plasma membrane. Although there is evidence that lipid rafts function as signaling platforms for CXCR chemokine receptors, their role in recognition systems for other chemotaxins such as leukotriene B4 (LTB4) and fMLP is unknown. To address this question, human neutrophils were extracted with 1% Brij-58 and fractionated on sucrose gradients. B leukotriene receptor-1 (BLT-1), the primary LTB4 receptor, partitioned to low density fractions, coisolating with the lipid raft marker, flotillin-1. By contrast, formyl peptide receptor (FPR), the primary fMLP receptor, partitioned to high density fractions, coisolating with a non-raft marker, Cdc42. This pattern was preserved after the cells were stimulated with LTB4 or fMLP. Fluorescence resonance energy transfer (FRET) was performed to confirm the proximity of BLT-1 and FPR with these markers. FRET was detected between BLT1 and flotillin-1 but not Cdc42, whereas FRET was detected between FPR and Cdc42, but not flotillin-1. Pretreating neutrophils with methyl-β-cyclodextrin, a lipid raft-disrupting agent, suppressed intracellular Ca2+ mobilization and ERK1/2 phosphorylation in response to LTB4 but had no effect on either of these responses to fMLP. We conclude that BLT-1 is physically located within lipid raft microdomains of human neutrophils and that disrupting lipid raft integrity suppresses LTB4-induced activation. By contrast, FPR is not associated with lipid rafts, and fMLP-induced signaling does not require lipid raft integrity. These findings highlight the complexity of chemotaxin signaling pathways and offer one mechanism by which neutrophils may spatially organize chemotaxin signaling within the plasma membrane.
Synovial Autoreactive T Cells in Rheumatoid Arthritis Resist IDO-Mediated Inhibition
Authors: Zhu Lingqiao , Ji Fang , Wang Yuan , Zhang Yi , Liu Qiang , Zhang Jingwu Z. , Matsushima Kouji , Cao Qi , Zhang Yanyun 
Published: April 2014

Abstract
A hallmark of T cell-mediated autoimmunity is the persistence of autoreactive T cells. However, it remains to elucidate the manner in which synovial T cells are sustained in patients with rheumatoid arthritis (RA). We found that dendritic cells (DC) and tissues from the synovial joints of RA patients expressed higher levels of IDO than DC from healthy donors. Interestingly, T cells derived from the joint synovial fluid (SF) of RA patients proliferated in response to either autologous or allogeneic IDO-positive DC, an outcome that was not affected by the addition of IDO inhibitor 1-methyl-d-tryptophan (1-MT). In contrast, addition of 1-MT to the culture stimulated with allogeneic or autologous IDO-positive DC significantly enhanced the proliferation of T cells derived from peripheral blood of healthy donors or from peripheral blood of RA patients. Furthermore, we found that functionally active tryptophanyl-tRNA-synthetase (TTS) was significantly elevated in T cells derived from the SF of RA patients, leading to enhanced storage of tryptophan in T cells and to subsequent resistance to IDO-mediated deprivation of tryptophan. The RA SF enhancement of TTS expression in T cells was blocked by mAb to IFN-γ and TNF-α. These results suggest that the resistance of T cells to IDO-mediated deprivation of tryptophan represents a mechanism by which autoreactive T cells are sustained in vivo in RA patients. Specifically, blocking of the up-regulation of TTS expression in T cells presents an avenue for development of a novel therapeutic approach to treatment of RA.
Mimicry and Antibody-Mediated Cell Signaling in Autoimmune Myocarditis
Authors: Li Ya , Heuser Janet S. , Cunningham Luke C. , Kosanke Stanley D. , Cunningham Madeleine W. 
Published: April 2014

Abstract
The mechanisms by which autoantibodies against cardiac myosin (CM) may lead to heart dysfunction is unknown. We show that autoantibodies to CM in anti-CM sera and mAbs derived from experimental autoimmune myocarditis targeted the heart cell surface and induced Ab-mediated cAMP-dependent protein kinase A activity. Ab-mediated cell signaling of protein kinase A was blocked by CM, anti-IgG, or by specific inhibitors of the β-adrenergic receptor (β-AR) pathway. mAbs confirmed mimicry between CM and the β-AR. Passive transfer of purified Ab (IgG) from CM-immunized rats resulted in IgG deposition and apoptosis in the heart, leading to a cardiomyopathic heart disease phenotype in recipients. Our novel findings link anti-CM Ab with the β-AR and subsequent Ab-mediated cell signaling in the heart.
Coadministration of Plasmid DNA Constructs Encoding an Encephalitogenic Determinant and IL-10 Elicits Regulatory T Cell-Mediated Protective Immunity in the Central Nervous System
Authors: Schif-Zuck Sagie , Wildbaum Gizi , Karin Nathan 
Published: April 2014

Abstract
We have previously shown that Ag-specific IL-10-producing regulatory T cells (Tr1) participate in the regulation of experimental autoimmune encephalomyelitis and that their specificity undergoes determinant spread in a reciprocal manner to effector T cell specificity. The current study shows that coadministration of plasmid DNA vaccines encoding IL-10 together with a plasmid encoding a myelin basic protein (MBP) encephalitogenic determinant during an ongoing disease rapidly amplifies this Tr1-mediated response, in a disease-specific manner. Thus, coadministration of both plasmids, but not the plasmid DNA encoding MBP alone, rapidly suppresses an ongoing disease. Tolerance included elevation in Ag-specific T cells producing IL-10 and an increase in apoptosis of cells around high endothelial venules in the CNS after successful therapy. Tolerance could be transferred by MBP-specific primary T cells isolated from protected donors and reversed by neutralizing Abs to IL-10 but not to IL-4. Due to the nature of determinant spread in this model, we could bring about evidence implying that rapid and effective induction of Tr1-induced active tolerance is dependent on redirecting the Tr1 response to the epitope to which the effector function dominates the response at a given time. The consequences of these findings to multiple sclerosis, and possibly other inflammatory autoimmune diseases are discussed.
Stability and Translation of TCR ζ mRNA Are Regulated by the Adenosine-Uridine-Rich Elements in Splice-Deleted 3′ Untranslated Region of ζ-Chain
Authors: Chowdhury Bhabadeb , Krishnan Sandeep , Tsokos Christos G. , Robertson James W. , Fisher Carolyn U. , Nambiar Madhusoodana P. , Tsokos George C. 
Published: April 2014

Abstract
Systemic lupus erythematosus (SLE) T cells display reduced expression of TCR ζ protein. Recently, we reported that in SLE T cells, the residual TCR ζ protein is predominantly derived from an alternatively spliced form that undergoes splice deletion of 562 nt (from 672 to 1233 bases) within the 3′ untranslated region (UTR) of TCR ζ mRNA. The stability and translation of the alternatively spliced form of TCR ζ mRNA are low compared with that of the wild-type TCR ζ mRNA. We report that two adenosine-uridine-rich sequence elements (AREs), defined by the splice-deleted 3′ UTR region, but not an ARE located upstream are responsible for securing TCR ζ mRNA stability and translation. The stabilizing effect of the splice-deleted region-defined AREs extended to the luciferase mRNA and was not cell type-specific. The findings demonstrate distinct sequences within the splice-deleted region 672 to 1233 of the 3′ UTR, which regulate the transcription, mRNA stability, and translation of TCR ζ mRNA. The absence of these sequences represents a molecular mechanism that contributes to altered TCR ζ-chain expression in lupus.
IL-22-Mediated Tumor Growth Reduction Correlates with Inhibition of ERK1/2 and AKT Phosphorylation and Induction of Cell Cycle Arrest in the G2-M Phase
Authors: Weber Georg F. , Gaertner Florian C. , Erl Wolfgang , Janssen Klaus-Peter , Blechert Birgit , Holzmann Bernhard , Weighardt Heike , Essler Markus 
Published: April 2014

Abstract
IL-22 is a recently discovered cytokine of the IL-10 family that binds to a class II cytokine receptor composed of IL-22R1 and IL-10R2c and influences a variety of immune reactions. As IL-22 has also been shown to modulate cell cycle and proliferation mediators such as ERK1/2 and JNK, we studied the role of IL-22 in proliferation, apoptosis, and cell cycle regulation in EMT6 murine breast cancer cells in vitro and in vivo. In this study, we report that murine breast cancer cells express functional IL-22R as indicated by RT-PCR studies, immunoblotting, and STAT3 activation assays. Importantly, IL-22 exposure of EMT6 cells resulted in decreased levels of phosphorylated ERK1/2 and AKT protein kinases, indicating an inhibitory effect of IL-22 on signaling pathways promoting cell proliferation. Furthermore, IL-22 induced a cell cycle arrest of EMT6 cells in the G2-M phase. IL-22 reduced EMT6 cell numbers and the proliferation rate by ∼50% as measured by [3H]thymidine incorporation. IL-22 treatment of EMT6 tumor-bearing mice lead to a decreased tumor size and a reduced tumor cell proliferation in vivo, as determined by 3′-deoxy-3′-fluorothymidine-positron emission tomography scans. Interestingly, IL-22 did not induce apoptosis, as determined in annexin V binding assay and caspase-3 activation assay and had no effect on angiogenesis in vivo. In conclusion, our results indicate that IL-22 reduced tumor growth by inhibiting signaling pathways such as ERK1/2 and AKT phosphorylation that promote tumor cell proliferation in EMT6 cells. Therefore, IL-22 may play a role in the control of tumor growth and tumor progression.
Alternative Translational Products and Cryptic T Cell Epitopes: Expecting the Unexpected
Authors: Ho On , Green William R. 
Published: April 2014

AbstractAlthough CD8 T cell epitopes have been studied extensively, often overlooked are unconventional cryptic epitopes generated from nontraditional sources of peptides/proteins and/or mechanisms of translation. In this review, we discuss alternative reading frame epitopes, both mechanistically and also in terms of their physiologic importance in the induction of antiviral and antitumor CTL responses. Issues of the influence of cryptic translational products on foreign and self-Ag diversity, thymic selection, and the T cell repertoire; disease pathogenesis; and approaches to vaccine design are discussed in context of the potentially large impact of unconventional epitopes on T cell immunity.
High Accumulation of T Regulatory Cells Prevents the Activation of Immune Responses in Aged Animals
Authors: Sharma Sanjay , Dominguez Ana Lucia , Lustgarten Joseph 
Published: April 2014

Abstract
In our previous in vivo study we demonstrated that young BALB/c mice effectively rejected the BM-185 tumor cells expressing enhanced GFP (EGFP) as a surrogate tumor Ag. In contrast, old BALB/c mice succumbed to the BM-185-EGFP tumors, indicating that there is a deficiency in old animals preventing the rejection of immunogenic tumors. There is cumulative evidence indicating that regulatory T (Treg) cells control the activation of primary and memory T cell responses. However, very little is known about whether there is a relation between Tregs and the lack of immune responses in the aged. We evaluated young and aged animals, and our results demonstrated that there are significantly more CD4+CD25+FoxP3+ and CD8+CD25+FoxP3+ Tregs in the spleen and lymph nodes of old animals when compared with the young. Depletion of CD25+ cells with anti-CD25 mAb induces the rejection of BM-185-EGFP cells, restores antitumor T cell cytotoxic activity, and results in the generation of a protective memory response against the BM-185 wild-type tumors in old mice. Furthermore, vaccination with CpG-oligodeoxynucleotide decreases the number of Treg cells in old animals to the same levels as young mice, restoring the primary and memory antitumor immune responses against BM-185-EGFP tumors. Taken together, these results indicate that there is a direct correlation between the expansion of Treg cells and immune deficiency in the old, and that depletion of these cells might be critical for restoring immune responses in aged animals.
Regulatory Roles of NKT Cells in the Induction and Maintenance of Cyclophosphamide-Induced Tolerance
Authors: Iwai Toshiro , Tomita Yukihiro , Okano Shinji , Shimizu Ichiro , Yasunami Yohichi , Kajiwara Takashi , Yoshikai Yasunobu , Taniguchi Masaru , Nomoto Kikuo , Yasui Hisataka 
Published: April 2014

AbstractWe have previously reported the sequential mechanisms of cyclophosphamide (CP)-induced tolerance. Permanent acceptance of donor skin graft is readily induced in the MHC-matched and minor Ag-mismatched recipients after treatment with donor spleen cells and CP. In the present study, we have elucidated the roles of NKT cells in CP-induced skin allograft tolerance. BALB/c AnNCrj (H-2d, Lyt-1.2, and Mls-1b) wild-type (WT) mice or Vα14 NKT knockout (KO) (BALB/c) mice were used as recipients, and DBA/2 NCrj (H-2d, Lyt-1.1, and Mls-1a) mice were used as donors. Recipient mice were primed with 1 × 108 donor SC i.v. on day 0, followed by 200 mg/kg CP i.p. on day 2. Donor mixed chimerism and permanent acceptance of donor skin allografts were observed in the WT recipients. However, donor skin allografts were rejected in NKT KO recipient mice. In addition, the donor reactive Vβ6+ T cells were observed in the thymus of a NKT KO recipient. Reconstruction of NKT cells from WT mice restored the acceptance of donor skin allografts. In addition, donor grafts were partially accepted in the thymectomized NKT KO recipient mice. Furthermore, the tolerogen-specific suppressor cell was observed in thymectomized NKT KO recipient mice, suggesting the generation of regulatory T cells in the absence of NTK cells. Our results suggest that NKT cells are essential for CP-induced tolerance and may have a role in the establishment of mixed chimerism, resulting in clonal deletion of donor-reactive T cells in the recipient thymus.
Viral Interference with B7-1 Costimulation: A New Role for Murine Cytomegalovirus Fc Receptor-1
Authors: Mintern Justine D. , Klemm Elizabeth J. , Wagner Markus , Paquet Marie Eve , Napier Melanie D. , Kim You Me , Koszinowski Ulrich H. , Ploegh Hidde L. 
Published: April 2014

AbstractMurine CMV (MCMV), a β-herpesvirus, infects dendritic cells (DC) and impairs their function. The underlying events are poorly described. In this study, we identify MCMV m138 as the viral gene responsible for promoting the rapid disappearance of the costimulatory molecule B7-1 (CD80) from the cell surface of DC. This was unexpected, as m138 was previously identified as fcr-1, a putative virus-encoded FcR. m138 impaired the ability of DC to activate CD8+ T cells. Biochemical analysis and immunocytochemistry showed that m138 targets B7-1 in the secretory pathway and reroutes it to lysosomal associated membrane glycoprotein-1+ compartments. These results show a novel function for m138 in MCMV infection and identify the first viral protein to target B7-1.
NK and CD4 Cells Collaborate to Protect against Melanoma Tumor Formation in the Brain
Authors: Prins Robert M. , Vo Dan D. , Khan-Farooqi Haumith , Yang Meng-Yin , Soto Horacio , Economou James S. , Liau Linda M. , Ribas Antoni 
Published: April 2014

Abstract
NK cells represent a potent immune effector cell type that have the ability to recognize and lyse tumors. However, the existence and function of NK cells in the traditionally “immune-privileged” CNS is controversial. Furthermore, the cellular interactions involved in NK cell anti-CNS tumor immunity are even less well understood. We administered non-Ag-loaded, immature dendritic cells (DC) to CD8α knockout (KO) mice and studied their anti-CNS tumor immune responses. DC administration induced dramatic antitumor immune protection in CD8α KO mice that were challenged with B16 melanoma both s.c. and in the brain. The CNS antitumor immunity was dependent on both CD4+ T cells and NK cells. Administration of non-Ag-loaded, immature DC resulted in significant CD4+ T cell and NK cell expansion in the draining lymph nodes at 6 days postvaccination, which persisted for 2 wk. Finally, DC administration in CD8α KO mice was associated with robust infiltration of CD4+ T cells and NK cells into the brain tumor parenchyma. These results represent the first demonstration of a potent innate antitumor immune response against CNS tumors in the absence of toxicity. Thus, non-Ag-loaded, immature DC administration, in the setting of CD8 genetically deficient mice, can induce dramatic antitumor immune responses within the CNS that surpass the effects observed in wild-type mice. Our results suggest that a better understanding of the cross-talk between DC and innate immune cells may provide improved methods to vaccinate patients with tumors located both systemically and within the CNS.
Asynchronous Differentiation of CD8 T Cells That Recognize Dominant and Cryptic Antigens
Authors: Baron Chantal , Meunier Marie-Christine , Caron Étienne , Côté Caroline , Cameron Mark J. , Kelvin David J. , LeBlanc Richard , Rineau Vincent , Perreault Claude 
Published: April 2014

Abstract
Restriction of T cell responses to a few epitopes (immunodominance) is a central feature of immune responses. We analyzed the entire transcriptome of effector CD8 T cells specific for a dominant (H7a) and a cryptic (HY) mouse Ag and performed a longitudinal analysis of selected T cell differentiation markers. We found that Ag specificity had a relatively modest influence on the repertoire of genes that are transcriptionally modulated by the CD8 T cell differentiation program. Although the differentiation programs of anti-H7a and anti-HY T cells were similar, they did not progress simultaneously. The expansion peak of anti-H7a T cells was reached on day 10 while that of anti-HY T cells was attained on days 15–20. Between days 10 and 20, anti-H7a T cells were in the contraction phase and anti-HY T cells in the expansion phase. Furthermore, expansion and development of effector function were well-synchronized in anti-H7a T cells but were disconnected in anti-HY T cells. We propose that, by leading to selective expansion of the fittest CD8 T cells, immunodominance may be beneficial to the host. Inhibition of the T cell response to cryptic Ag would ensure that host resources (APC, cytokines) for which T cells compete are devoted to T cells with the best effector potential. One implication is that favoring expansion of the fittest effector T cells in general may be more important than increasing the diversity of the T cell repertoire.
Local and Systemic Effects of Intranodally Injected CpG-C Immunostimulatory-Oligodeoxyribonucleotides in Macaques
Authors: Teleshova Natalia , Kenney Jessica , Van Nest Gary , Marshall Jason , Lifson Jeffrey D. , Sivin Irving , Dufour Jason , Bohm Rudolf , Gettie Agegnehu , Robbiani Melissa 
Published: April 2014

Abstract
Immunostimulatory CpG-C oligodeoxyribonucleotides (ISS-ODNs) represent a promising strategy to enhance vaccine efficacy. We have shown that the CpG-C ISS-ODN C274 stimulates macaque blood dendritic cells (DCs) and B cells and augments SIV-specific IFN-γ responses in vitro. To further explore the potential of C274 for future vaccine studies, we assessed the in vivo effects of locally administered C274 (in naive and healthy infected macaques). Costimulatory molecules were marginally increased on DCs and B cells within cells isolated from C274-injected lymph nodes (LNs). However, cells from C274-injected LNs exhibited heightened responsiveness to in vitro culture. This was particularly apparent at the level of CD80 (less so CD86) expression by CD123+ plasmacytoid DCs and was further boosted in the presence of additional C274 in vitro. Notably, cells from C274-injected LNs secreted significantly elevated levels of several cytokines and chemokines upon in vitro culture. This was more pronounced when cells were exposed to additional stimuli in vitro, producing IFN-α, IL-3, IL-6, IL-12, TNF-α, CCL2, CCL3, CCL5, and CXCL8. Following C274 administration in the absence of additional SIV Ag, endogenous IFN-γ secretion was elevated in LN cells of infected animals, but SIV-specific responses were unchanged. Endogenous and SIV-specific responses decreased in blood, before the SIV-specific responses rebounded by 2 wk after C274 treatment. Elevated IFN-α, CCL2, and CCL5 were also detected in the plasma after C274 injection. Thus, locally administered C274 has local and systemic activities, supporting the potential for CpG-C ISS-ODNs to boost immune function to enhance anti-HIV vaccine immunogenicity.
Lysophosphatidylcholine Stimulates IL-1β Release from Microglia via a P2X7 Receptor-Independent Mechanism
Authors: Stock Christian , Schilling Tom , Schwab Albrecht , Eder Claudia 
Published: April 2014

Abstract
IL-1β released from activated macrophages contributes significantly to tissue damage in inflammatory, degenerative, and autoimmune diseases. In the present study, we identified a novel mechanism of IL-1β release from activated microglia (brain macrophages) that occurred independently of P2X7 ATP receptor activation. Stimulation of LPS-preactivated microglia with lysophosphatidylcholine (LPC) caused rapid processing and secretion of mature 17-kDa IL-1β. Neither LPC-induced IL-1β release nor LPC-stimulated intracellular Ca2+ increases were affected by inhibition of P2X7 ATP receptors with oxidized ATP. Microglial LPC-induced IL-1β release was suppressed in Ca2+-free medium or during inhibition of nonselective cation channels with Gd3+ or La3+. It was also attenuated when Ca2+-activated K+ channels were blocked with charybdotoxin (CTX). The electroneutral K+ ionophore nigericin did not reverse the suppressive effects of CTX on LPC-stimulated IL-1β release, demonstrating the importance of membrane hyperpolarization. Furthermore, LPC-stimulated caspase activity was unaffected by Ca2+-free medium or CTX, suggesting that secretion but not processing of IL-1β is Ca2+- and voltage-dependent. In summary, these data indicate that the activity of nonselective cation channels and Ca2+-activated K+ channels is required for optimal IL-1β release from LPC-stimulated microglia.