bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Mechanisms of B Lymphocyte Activation by the Immune Response Modifier R-848
Authors: Bishop Gail A. , Hsing Yina , Hostager Bruce S. , Jalukar Sangita V. , Ramirez Luis M. , Tomai Mark A. 
Published: April 2014

AbstractThe imidazoquinoline R-848, originally identified as a highly effective antiviral agent, has recently been shown to be capable of potent B lymphocyte activation. The B cell-activating properties of R-848 are strikingly similar to the effects of the CD40 ligand CD154. The present study demonstrates that this similarity extends to the intracellular signaling pathways triggered by the compound, although both overlapping and distinct mechanisms of signaling were seen. Like CD40 ligation, R-848 stimulated activation of the stress-activated protein kinases c-Jun kinase and p38 and activated the NF-κB family of transcription factors. Both R-848- and CD40-mediated B cell differentiation were dependent upon NF-κB activation, although the relative importance of individual NF-κB family members appeared to differ between R-848- and CD40-mediated signals. Both signals were partially dependent upon induction of TNF-α and IL-6, and the cytoplasmic adaptor molecule TNF receptor-associated factor 2 is involved in both R-848- and CD40-mediated differentiation.
A Critical Role for B Cells in the Development of Memory CD4 Cells
Authors: Linton Phyllis-Jean , Harbertson Judith , Bradley Linda M. 
Published: April 2014

AbstractActivated B cells express high levels of class II MHC and costimulatory molecules and are nearly as effective as dendritic cells in their APC ability. Yet, their importance as APC in vivo is controversial and their role, if any, in the development of CD4 memory is unknown. We compared responses of CD4 cells from normal and B cell-deficient mice to keyhole limpet hemocyanin over 6 mo and observed diminished IL-2 production by cells primed in the absence of B cells. This was due to lower frequencies of Ag-responsive cells and not to decreased levels of IL-2 secretion per cell. The absence of B cells did not affect the survival of memory CD4 cells since frequencies remained stable. Despite normal dendritic cell function, multiple immunizations of B cell-deficient mice did not restore frequencies of memory cells. However, the transfer of B cells restored memory cell development. Ag presentation was not essential since B cells activated in vitro with irrelevant Ag also restored frequencies of memory cells. The results provide unequivocal evidence that B cells play a critical role in regulating clonal expansion of CD4 cells and, as such, are requisite for the optimal priming of memory in the CD4 population.
Role of STAT4 and STAT6 Signaling in Allograft Rejection and CTLA4-Ig-Mediated Tolerance
Authors: Zhou Ping , Szot Greg L. , Guo Zhong , Kim Oliver , He Gang , Wang Jun , Grusby Michael J. , Newell Kenneth A. , Thistlethwaite J. Richard , Bluestone Jeffrey A. , Alegre Maria-Luisa 
Published: April 2014

AbstractSTAT4−/− mice have impaired type 1 T cell differentiation, whereas STAT6−/− mice fail to generate type 2 responses. The role of type 1 and type 2 T cell differentiation in acute cardiac allograft rejection and in the induction of tolerance was examined in wild-type, STAT4−/−, and STAT6−/− recipients. All recipients rejected the grafts promptly. Analysis of in situ cytokine gene expression in the allografts confirmed decreased levels of IFN-γ in STAT4−/− recipients and undetectable levels of IL-4 and IL-5 in STAT6−/− mice. Blockade of the CD28/B7 costimulatory pathway prolonged cardiac graft survival for &gt;100 days in 100% of wild-type and STAT4−/− mice. However, 14% of CTLA4-Ig-treated STAT6−/− mice rejected their grafts between 20 and 100 days. Moreover, of those animals followed past 100 days, 60% of the STAT6−/− mice rejected their grafts. Splenocytes harvested on day 145 posttransplant from CTLA4-Ig-treated rejecting STAT6−/− recipients were transfused into syngeneic SCID mice transplanted with donor or third party cardiac allografts. Both donor and third party grafts were rejected, indicating that the initial graft loss may be due to an immunological rejection. In contrast, when splenocytes from CTLA4-Ig-treated wild-type or nonrejecting STAT6−/− mice were transferred into SCID recipients, donor allografts were accepted, but third party hearts were rejected. Thus, long-term prolongation of cardiac allograft survival by CTLA4-Ig is STAT4-independent but, at least in part, STAT6-dependent. These data suggest that the balance of type 1 and type 2 T lymphocyte differentiation is not critical for acute rejection but influences the robust tolerance induced by CD28/B7 blockade in this model.
The Neuropeptide Substance P Activates p38 Mitogen-Activated Protein Kinase Resulting in IL-6 Expression Independently from NF-κB
Authors: Fiebich Bernd L. , Schleicher Sandra , Butcher Russel D. , Craig Alexander , Lieb Klaus 
Published: April 2014

AbstractSubstance P (SP), a member of the tachykinin peptide family, is a major mediator of neuroimmunomodulatory activities and neurogenic inflammation within the central and peripheral nervous system. SP has been shown to induce the expression of proinflammatory cytokines such as IL-6, which might be implicated in the etiopathology of several human brain disorders. We showed in a previous study that nanomolar concentrations of SP triggered activation of NF-κB, a transcription factor involved in the control of cytokine expression. However, activation of NF-κB was not involved in SP-induced expression of IL-6. Here, we describe p38 mitogen-activated protein kinase (p38 MAPK) as a signal transduction component that operates independently from NF-κB activation and that mediates SP-induced IL-6 expression in the human astrocytoma cell line U373 MG. SP induced the phosphorylation of p38 MAPK within 10 min, and this activation persisted up to 30 min and was independent from p42/44 MAPKs and protein kinase C activation, which all are induced after stimulation with SP. As shown by EMSA, p38 MAPK was not involved in SP-induced activation of NF-κB. p38 MAPK, however, mediated SP-induced IL-6 expression as shown by the use of specific inhibitors of this kinase. Our results suggest that activation of p38 MAPK is an important component controlling neurogenic inflammation within the CNS independently from NF-κB. Drugs targeting this MAPK may therefore interfere with SP-correlated neuropsychiatric disorders and may represent a therapeutic approach in these disorders.
TNF Regulates Thymocyte Production by Apoptosis and Proliferation of the Triple Negative (CD3−CD4−CD8−) Subset
Authors: Baseta Juana Gonzalez , Stutman Osias 
Published: April 2014

AbstractTNF is a proinflammatory cytokine with opposing death/no-death effects in vivo and in vitro. Our studies showed that TNF regulates mouse thymocyte production, inducing both apoptosis and proliferation of the most immature CD3−CD4−CD8− triple negative (TN) subset within a broad range of dosages (101–105 pg/ml) in the presence of IL-7. TNF apoptosis affected only the TN3 (CD44−CD25+) and TN4 (CD44−CD25−) subsets that expressed both TNFR-p55 and -p75. Although each TNFR alone could mediate TNF apoptosis, maximal apoptosis was seen in C57BL/6J wild type, which expressed both TNFRs. TNF also induced proliferation of TN3 cells at higher doses (104–105 pg/ml) mediated only by TNFR-p75. Both anti-TNFR-p55 and -TNFR-p75 mAb inhibited apoptosis but only anti-p75 inhibited proliferation. TNF also regulated TN proliferation to IL-7 because TNFR knockout (KO), TNF KO, and TNF/lymphotoxin α and β triple KO mice showed 2- to 3-fold increased responses not seen in C57BL/6J wild type. In vivo, TNFR KO mice showed thymic hypertrophy with a 60% increase in total thymocytes, with no effect on the CD4/CD8 subsets. We conclude that TNF maintains homeostatic control of total thymocyte production by negative selection of TN3 and TN4 prothymocytes and down-regulation of their proliferation to endogenous IL-7.
Mechanisms of Tolerance Induction by a Gene-Transferred Peptide-IgG Fusion Protein Expressed in B Lineage Cells
Authors: El-Amine Moustapha , Melo Marco , Kang Yubin , Nguyen Hao , Qian Jiahua , Scott David W. 
Published: April 2014

Abstract
A gene therapy model has been designed to induce tolerance to multiple epitopes expressed in-frame on a soluble IgG fusion protein scaffold. Tolerance to the λ repressor cI sequence p1-102 or its immunodominant epitopes (p12-26, p73-88) can be elicited when bone marrow (BM) or LPS blasts are transduced and injected into naive or even primed recipients. To explore the mechanism of tolerance, class II−/− (knockout, KO) BM cells were transduced with p1-102-IgG and transferred to irradiated recipients. These cells failed to induce tolerance to challenge with p1-102 epitopes, whereas transduced +/+ BM cells did. This supports the importance of class II MHC on the tolerogenic APC rather than secretion and representation in tolerogenesis. When BM cells from μMT KO mice were transfected with p12-26-IgG and injected into irradiated mice, these transduced BM cells also failed to induce tolerance to an immunodominant epitope. These results suggest the direct involvement of B cells in tolerance to p1-102 epitopes. IL-10 KO BM cells infected with a p12-26-IgG construct were still tolerogenic. Importantly, anti-CTLA-4 injections reversed tolerance in primed, but not in naive, recipients of transduced LPS blasts. These data emphasize the importance of MHC class II presentation, B cell involvement, and CTLA-4 engagement in induction and/or maintenance of tolerance.
Kb, Kd, and Ld Molecules Share Common Tapasin Dependencies as Determined Using a Novel Epitope Tag
Authors: Myers Nancy B. , Harris Michael R. , Connolly Janet M. , Lybarger Lonnie , Yu Yik Y. L. , Hansen Ted H. 
Published: April 2014

AbstractThe endoplasmic reticulum protein tapasin is considered to be a class I-dedicated chaperone because it facilitates peptide loading by proposed mechanisms such as peptide editing, endoplasmic reticulum retention of nonpeptide-bound molecules, and/or localizing class I near the peptide source. Nonetheless, the primary functions of tapasin remain controversial as do the relative dependencies of different class I molecules on tapasin for optimal peptide loading and surface expression. Tapasin dependencies have been addressed in previous studies by transfecting different class I alleles into tapasin-deficient LCL721.220 cells and then monitoring surface expression and Ag presentation to T cells. Indeed, by these criteria, class I alleles have disparate tapasin-dependencies. In this study, we report a novel and more direct method of comparing tapasin dependency by monitoring the ratio of folded vs open forms of the different mouse class I heavy chains, Ld, Kd, and Kb. Furthermore, we determine the amount of de novo heavy chain synthesis required to attain comparable expression in the presence vs absence of tapasin. Our findings show that tapasin dramatically improves peptide loading of all three of these mouse molecules.
Export of the High Affinity IgE Receptor From the Endoplasmic Reticulum Depends on a Glycosylation-Mediated Quality Control Mechanism
Authors: Albrecht Bettina , Woisetschläger Maximilian , Robertson Michael W. 
Published: April 2014

AbstractThe high affinity IgE receptor (FcεRI) is a multisubunit complex comprised of either αγ2 or αβγ2 chains. The cotranslational assembly of the IgE-binding α-chain with a dimer of γ-chains occurs in a highly controlled manner and is proposed to involve masking of a dilysine motif present at the cytoplasmic C terminus of the FcεRI α-chain that targets localization of this subunit to the endoplasmic reticulum (ER). Here, we show that ER quality control modulates export from the ER of newly synthesized αγ2 and αβγ2 receptors. We demonstrate that the presence of untrimmed N-linked core glycans (Glc3Man9GlcNAc2) on the FcεRI α-chain activates the ER quality control mechanism to retain this subunit in the ER, despite the presence of γ-chains. At the same time, the untrimmed, ER-localized α-chain exhibits IgE-binding activity, suggesting that FcεRI α-chain folding occurs before constitutive glucose trimming. In additional experiments, we demonstrate that cell surface expression of an α-chain C-terminal truncation mutant is also dependent on glucose trimming, but not on γ-chain coexpression. We suggest that glucosidase trimming of terminal glucose residues is a critical control step in the export of FcεRIα from the ER. Finally, we show that the constitutive ER FcεRI α-chain, expressed in the absence of the other FcεRI subunits, associates with the ER lectin-like chaperone calnexin, but not the structurally similar ER chaperone calreticulin, presumably through interaction with monoglucosylated α-chain ER glycoforms.
Helper-Independent, L-Selectinlow CD8+ T Cells with Broad Anti-Tumor Efficacy Are Naturally Sensitized During Tumor Progression
Authors: Peng Liaomin , Kjaergaard Jørgen , Plautz Gregory E. , Weng David E. , Shu Suyu , Cohen Peter A. 
Published: April 2014

AbstractWe recently reported that the CD4+ T cell subset with low L-selectin expression (CD62Llow) in tumor-draining lymph nodes (TDLN) can be culture activated and adoptively transferred to eradicate established pulmonary and intracranial tumors in syngeneic mice, even without coadministration of IL-2. We have extended these studies to characterize the small subset of L-selectinlow CD8+ T cells naturally present in TDLN of mice bearing weakly immunogenic tumors. Isolated L-selectinlow CD8+ T cells displayed the functional phenotype of helper-independent T cells, and when adoptively transferred could consistently eradicate, like L-selectinlow CD4+ T cells, both established pulmonary and intracranial tumors without coadministration of exogenous IL-2. Whereas adoptively transferred L-selectinlow CD4+ T cells were more potent on a cell number basis for eradicating 3-day intracranial and s.c. tumors, L-selectinlow CD8+ T cells were more potent against advanced (10-day) pulmonary metastases. Although the presence of CD4+ T cells enhanced generation of L-selectinlow CD8+ effector T cells, the latter could also be obtained from CD4 knockout mice or normal mice in vivo depleted of CD4+ T cells before tumor sensitization. Culture-activated L-selectinlow CD8+ T cells did not lyse relevant tumor targets in vitro, but secreted IFN-γ and GM-CSF when specifically stimulated with relevant tumor preparations. These data indicate that even without specific vaccine maneuvers, progressive tumor growth leads to independent sensitization of both CD4+ and CD8+ anti-tumor T cells in TDLN, phenotypically L-selectinlow at the time of harvest, each of which requires only culture activation to unmask highly potent stand-alone effector function.
Modulation of Innate and Acquired Immune Responses by Escherichia coli Heat-Labile Toxin: Distinct Pro- and Anti-Inflammatory Effects of the Nontoxic AB Complex and the Enzyme Activity
Authors: Ryan Elizabeth J. , McNeela Edel , Pizza Mariagrazia , Rappuoli Rino , O’Neill Luke , Mills Kingston H. G. 
Published: April 2014

Abstract
We have examined the roles of enzyme activity and the nontoxic AB complex of heat-labile toxin (LT) from Escherichia coli on its adjuvant and immunomodulatory properties. LTK63, an LT mutant that is completely devoid of enzyme activity, enhanced Th1 responses to coinjected Ags at low adjuvant dose. In contrast, LTR72, a partially detoxified mutant, enhanced Th2 responses and when administered intranasally to mice before infection with Bordetella pertussis suppressed Th1 responses and delayed bacterial clearance from the lungs. LTR72 or wild-type LT inhibited Ag-induced IFN-γ production by Th1 cells, and LT enhanced IL-5 production by Th2 cells in vitro. Each of the toxins enhanced B7-1 expression on macrophages, but enhancement of B7-2 expression was dependent on enzyme activity. We also observed distinct effects of the nontoxic AB complex and enzyme activity on inflammatory cytokine production. LT and LTR72 suppressed LPS and IFN-γ induced TNF-α and IL-12 production, but enhanced IL-10 secretion by macrophages in vitro and suppressed IL-12 production in vivo in a murine model of LPS-induced shock. In contrast, LTK63 augmented the production of IL-12 and TNF-α. Furthermore, LTK63 enhanced NF-κB translocation, whereas low doses of LTR72 or LT failed to activate NF-κB, but stimulated cAMP production. Thus, E. coli LT appears to be capable of suppressing Th1 responses and enhancing Th2 responses through the modulatory effects of enzyme activity on NF-κB activation and IL-12 production. In contrast, the nontoxic AB complex can stimulate acquired immune responses by activating components of the innate immune system.
Monocytic Cells Synthesize, Adhere to, and Migrate on Laminin-8 (α4β1γ1)
Authors: Pedraza Claudio , Geberhiwot Tarekegn , Ingerpuu Sulev , Assefa Daniel , Wondimu Zenebech , Kortesmaa Jarkko , Tryggvason Karl , Virtanen Ismo , Patarroyo Manuel 
Published: April 2014

Abstract
Laminins, a growing family of large heterotrimeric proteins with cell adhesive and signaling properties, are major components of vascular and other basement membranes. Expression, recognition, and use of laminin isoforms by leukocytes are poorly understood. In monoblastic THP-1 cells, transcripts for laminin γ1-, β1-, and α4-chains were detected by RT-PCR. Following immunoaffinity purification on a laminin β1 Ab-Sepharose column, laminin β1- (220 kDa), γ1- (200 kDa), and α4- (180/200 kDa) chains were detected by Western blotting in THP-1 cells and in two other monoblastic cell lines, U-937 and Mono Mac 6. After cell permeabilization, a mAb to laminin γ1-chain reacted with practically all blood monocytes by immunofluorescence flow cytometry, and laminin-8 (α4β1γ1) could be isolated also from these cells. Monoblastic JOSK-I cells adhered constitutively to immobilized recombinant laminin-8, less than to laminin-10/11 (α5β1γ1/α5β2γ1) but to a higher level than to laminin-1 (α1β1γ1). Compared with the other laminin isoforms, adhesion to laminin-8 was preferentially mediated by α6β1 and β2 integrins. Laminin-8 and, to a lower extent, laminin-1 promoted spontaneous and chemokine-induced migration of blood monocytes, whereas laminin-10/11 was inhibitory. Altogether, the results indicate that leukocytes, as other cell types, are able to synthesize complete laminin molecules. Expression, recognition, and use of laminin-8 by leukocytes suggest a major role of this laminin isoform in leukocyte physiology.
Deficiency of Src Homology 2-Containing Phosphatase 1 Results in Abnormalities in Murine Neutrophil Function: Studies inMotheatenMice
Authors: Kruger Joshua , Butler Jeffrey R. , Cherapanov Vera , Dong Qin , Ginzberg Hedy , Govindarajan Anand , Grinstein Sergio , Siminovitch Katherine A. , Downey Gregory P. 
Published: April 2014

AbstractNeutrophils, an essential component of the innate immune system, are regulated in part by signaling pathways involving protein tyrosine phosphorylation. While protein tyrosine kinase functions in regulating neutrophil behavior have been extensively investigated, little is known about the role for specific protein tyrosine phosphatases (PTP) in modulating neutrophil signaling cascades. A key role for Src homology 2 domain-containing phosphatase 1 (SHP-1), a PTP, in neutrophil physiology is, however, implied by the overexpansion and inappropriate activation of granulocyte populations in SHP-1-deficient motheaten (me/me) and motheaten viable (mev/mev) mice. To directly investigate the importance of SHP-1 to phagocytic cell function, bone marrow neutrophils were isolated from both me/me and mev/mev mice and examined with respect to their responses to various stimuli. The results of these studies revealed that both quiescent and activated neutrophils from motheaten mice manifested enhanced tyrosine phosphorylation of cellular proteins in the 60- to 80-kDa range relative to that detected in wild-type congenic control neutrophils. Motheaten neutrophils also demonstrated increased oxidant production, surface expression of CD18, and adhesion to protein-coated plastic. Chemotaxis, however, was severely diminished in the SHP-deficient neutrophils relative to control neutrophils, which was possibly attributable to a combination of defective deadhesion and altered actin assembly. Taken together, these results indicate a significant role for SHP-1 in modulating the tyrosine phosphorylation-dependent signaling pathways that regulate neutrophil microbicidal functions.
A Targeted DNA Vaccine Augments the Natural Immune Response to Self TNF-α and Suppresses Ongoing Adjuvant Arthritis
Authors: Wildbaum Gizi , Youssef Sawsan , Karin Nathan 
Published: April 2014

AbstractDepending on the mode of immunization, a single administration of CFA may result in the development of a local inflammatory process or chronic poly adjuvant-induced arthritis (AA). Administration of naked DNA encoding TNF-α results in the generation of immunological memory to its gene product. Upon induction of AA, this memory effectively inhibited the development of disease. Self-specific Abs developed in DNA-vaccinated animals were neutralizing in vitro and could adoptively transfer the beneficial effect of the vaccine. Administration of CFA to induce a local delayed-type hypersensitivity response rather than AA did not lead to an elicited production of Abs to the gene product of the above vaccine. Thus, elicitation of protective immunity is dependent on the development of an autoimmune condition. Most importantly, the administration of the TNF-α DNA construct after the onset of disease led to a rapid, long-lasting remission. This suggests a highly effective way by which a DNA vaccine encoding an autologous proinflammatory cytokine can be used to reprogram the immune system to generate protective immunity to its own potentially harmful activities.
Chemically Modified Ribozyme to V Gene Inhibits Anti-DNA Production and the Formation of Immune Deposits Caused by Lupus Lymphocytes
Authors: Suzuki Yoko , Funato Tadao , Munakata Yasuhiko , Sato Kanako , Hirabayashi Yasuhiko , Ishii Tomonori , Takasawa Naruhiko , Ootaka Tetsuya , Saito Takao , Sasaki Takeshi 
Published: April 2014

AbstractA variety of autoantibodies is responsible for the tissue injury in autoimmune diseases. We have demonstrated that the human anti-DNA Ab O-81, of which Ids are commonly detected in renal glomeruli of active lupus nephritis, uses the V3-7 gene. We tried to develop a new therapy for lupus nephritis by using chemically modified ribozymes to specifically inhibit the expression of the mRNA of Ig V gene. The transfection of hammerhead ribozyme or the addition of chemically modified ribozyme against the flanking region of V3-7 caused a potent and selective inhibition of anti-DNA production in V3-7-using B cell clones, but not in irrelevant V gene-using clones in vitro. Chemically modified ribozyme was long-acting and resistant to RNase, and nonspecific cytotoxicity of the ribozyme was negligible. To know the efficacy of the ribozyme in vivo, we used a model of immune complex nephritis in SCID mice in which 5 × 106 PBLs from patients with active lupus nephritis (lupus PBL) were transferred twice. The injection of lupus PBL in combination with chemically modified ribozyme to increase resistance to RNase significantly reduced anti-DNA Ab levels in blood and decreased levels of urinary protein in the immune deposit models. Immunofluorescence study also revealed a marked decrease in IgG deposits at renal glomeruli in the ribozyme-treated group. These results indicate an efficacy of chemically modified ribozyme therapy for autoantibody-mediated immune diseases.