bluuebunny/crossref_metadata_2025_split huggingface dataset:
Repression of IL-2 Promoter Activity by the Novel Basic Leucine Zipper p21SNFT Protein
Authors: Iacobelli Milena , Wachsman William , McGuire Kathleen L. 
Published: April 2014

Abstract
IL-2 is the major autocrine and paracrine growth factor produced by T cells upon T cell stimulation. The inducible expression of IL-2 is highly regulated by multiple transcription factors, particularly AP-1, which coordinately activate the promoter. Described here is the ability of the novel basic leucine zipper protein p21SNFT to repress AP-1 activity and IL-2 transcription. A detailed analysis of the repression by p21SNFT repression on the IL-2 promoter distal NF-AT/AP-1 site demonstrates that it can bind DNA with NF-AT and Jun, strongly suggesting that it represses NF-AT/AP-1 activity by competing with Fos proteins for Jun dimerization. The importance of this repression is that p21SNFT inhibits the trans-activation potential of protein complexes that contain Jun, thereby demonstrating an additional level of control for the highly regulated, ubiquitous AP-1 transcription factor and the IL-2 gene.
Identification of a Novel Tumor-Specific CTL Epitope Presented by RMA, EL-4, and MBL-2 Lymphomas Reveals Their Common Origin
Authors: van Hall Thorbald , van Bergen Jeroen , van Veelen Peter A. , Kraakman Margriet , Heukamp Lukas C. , Koning Frits , Melief Cornelis J. M. , Ossendorp Ferry , Offringa Rienk 
Published: April 2014

AbstractC57BL/6 mice generate a vigorous H-2Db-restricted CTL response against murine leukemia virus (MuLV)-induced tumors. For many years it has been suggested that this response is directed to an MuLV-encoded peptide as well as to a nonviral tumor-associated peptide. Recently, a peptide from the leader sequence of gag was demonstrated to be the MuLV-derived epitope. Here we describe the molecular identification of the tumor-associated epitope. Furthermore, we show that the CTL response against this epitope can restrict the outgrowth of MuLV-induced tumors in vivo. The epitope is selectively presented by the MuLV-induced T cell tumors RBL-5, RMA, and MBL-2 as well as by the chemically induced T cell lymphoma EL-4. Intriguingly, these tumors share expression of the newly identified epitope because they represent variants of the same clonal tumor cell line, as evident from sequencing of the TCR α- and β-chains, which proved to be identical. Our research shows that all sources of RBL-5, RMA, RMA-S, MBL-2, and EL-4 tumors are derived from a single tumor line, most likely EL-4.
Interaction of C1q and Mannan-Binding Lectin (MBL) with C1r, C1s, MBL-Associated Serine Proteases 1 and 2, and the MBL-Associated Protein MAp19
Authors: Thiel Steffen , Petersen Steen V. , Vorup-Jensen Thomas , Matsushita Misao , Fujita Teizo , Stover Cordula M. , Schwaeble Wilhelm J. , Jensenius Jens C. 
Published: April 2014

AbstractMannan-binding lectin (MBL) and C1q activate the complement cascade via attached serine proteases. The proteases C1r and C1s were initially discovered in a complex with C1q, whereas the MBL-associated serine proteases 1 and 2 (MASP-1 and -2) were discovered in a complex with MBL. There is controversy as to whether MBL can utilize C1r and C1s or, inversely, whether C1q can utilize MASP-1 and 2. Serum deficient in C1r produced no complement activation in IgG-coated microwells, whereas activation was seen in mannan-coated microwells. In serum, C1r and C1s were found to be associated only with C1q, whereas MASP-1, MASP-2, and a third protein, MAp19 (19-kDa MBL-associated protein), were found to be associated only with MBL. The bulk of MASP-1 and MAp19 was found in association with each other and was not bound to MBL or MASP-2. The interactions of MASP-1, MASP-2, and MAp19 with MBL differ from those of C1r and C1s with C1q in that both high salt concentrations and calcium chelation (EDTA) are required to fully dissociate the MASPs or MAp19 from MBL. In the presence of calcium, most of the MASP-1, MASP-2, and MAp19 emerged on gel-permeation chromatography as large complexes that were not associated with MBL, whereas in the presence of EDTA most of these components formed smaller complexes. Over 95% of the total MASPs and MAp19 found in serum are not complexed with MBL.
Treatment of Human B Cell Lymphoma Xenografts with a CD3 × CD19 Diabody and T Cells
Authors: Cochlovius Björn , Kipriyanov Sergey M. , Stassar Marike J. J. G. , Christ Oliver , Schuhmacher Jochen , Strauß Gudrun , Moldenhauer Gerhard , Little Melvyn 
Published: April 2014

Abstract
The use of anti-CD3 × antitumor bispecific Abs is an attractive and highly specific approach in cancer therapy. Recombinant Ab technology now provides powerful tools to enhance the potency of such immunotherapeutic constructs. We designed a heterodimeric diabody specific for human CD19 on B cells and CD3ε chain of the TCR complex. After production in Escherichia coli and purification, we analyzed its affinity, stability, and pharmacokinetics, and tested its capacity to stimulate T cell proliferation and mediate in vitro lysis of CD19+ tumor cells. The effect of the diabody on tumor growth was investigated in an in vivo model using immunodeficient mice bearing a human B cell lymphoma. The CD3 × CD19 diabody specifically interacted with both CD3- and CD19-positive cells, was able to stimulate T cell proliferation in the presence of tumor cells, and induced the lysis of CD19+ cells in the presence of activated human PBL. The lytic potential of the diabody was enhanced in the presence of an anti-CD28 mAb. In vivo experiments indicated a higher stability and longer blood retention of diabodies compared with single chain Fv fragments. Treatment of immunodeficient mice bearing B lymphoma xenografts with the diabody and preactivated human PBL efficiently inhibited tumor growth. The survival time was further prolonged by including the anti-CD28 mAb. The CD3 × CD19 diabody is a powerful tool that should facilitate the immunotherapy of minimal residual disease in patients with B cell leukemias and malignant lymphomas.
IL-12 Is Required to Maintain a Th1 Response DuringLeishmania majorInfection
Authors: Park Audrey Y. , Hondowicz Brian D. , Scott Phillip 
Published: April 2014

AbstractIL-12 initiates Th1 cell development and cell-mediated immunity, but whether IL-12 contributes to the maintenance of a Th1 response is unclear. To address this question, we infected IL-12 p40−/− C57BL/6 mice with Leishmania major, an intracellular protozoan parasite controlled by a cell-mediated immune response, and simultaneously administered IL-12. Whereas untreated p40−/− mice developed an uncontrolled infection, p40−/− mice treated with IL-12 for the first 2 or 4 wk of infection developed a Th1 response and resolved their lesions. However, the induction of this protective Th1 cell response by IL-12 treatment was not associated with long term immunity. We observed that on rechallenge in the absence of IL-12, the mice exhibited a susceptible phenotype. In addition, without rechallenge, lesions in the IL-12-treated p40−/− mice developed several weeks after cessation of IL-12 treatment. In both cases, disease was associated with the loss of a Th1 response and the development of a Th2 response. Our observations are not limited to the C57BL/6 strain, because IL-12 treatment was also unable to provide lasting protection to p40−/− BALB/c mice. Finally, we found that although Th1 cells from healed wild-type C57BL/6 mice adoptively transferred protection to L. major-infected RAG−/− mice, they were unable to protect p40−/− mice. In conclusion, these studies provide the first demonstration that IL-12 is required not only to initiate Th1 cell development but also throughout infection to maintain a Th1 cell response and resistance to L. major.
InvasiveShigella flexneriActivates NF-κB Through a Lipopolysaccharide-Dependent Innate Intracellular Response and Leads to IL-8 Expression in Epithelial Cells
Authors: Philpott Dana J. , Yamaoka Shoji , Israël Alain , Sansonetti Philippe J. 
Published: April 2014

AbstractThe pathogenesis of Shigella flexneri infection centers on the ability of this organism to invade epithelial cells and initiate an intense inflammatory reaction. Because NF-κB is an important transcriptional regulator of genes involved in inflammation, we investigated the role of this transcription factor during S. flexneri infection of epithelial cells. Infection of HeLa cells with invasive S. flexneri induced NF-κB DNA-binding activity; noninvasive S. flexneri strains did not lead to this activation. The pathway leading to NF-κB activation by invasive S. flexneri involved the kinases, NF-κB-inducing kinase, IκB kinase-1, and IκB kinase-2. NF-κB activation was linked to inflammation, because invasive S. flexneri activated an IL-8 promoter-driven reporter gene, and the κB site within this promoter was indispensable for its induction. Microinjection of bacterial culture supernatants into HeLa cells suggested that LPS is responsible for NF-κB activation by S. flexneri infection. In conclusion, the eukaryotic transcription factor NF-κB was activated during S. flexneri infection of epithelial cells, which suggests a role for this transcriptional regulator in modulating the immune response during infection in vivo.
Mycobacterium tuberculosis-Reactive CD8+ T Lymphocytes: The Relative Contribution of Classical Versus Nonclassical HLA Restriction
Authors: Lewinsohn David M. , Briden Andria L. , Reed Steven G. , Grabstein Kenneth H. , Alderson Mark R. 
Published: April 2014

AbstractPrevious studies in mice and humans models have suggested an important role for CD8+ T cells in host defense to Mycobacterium tuberculosis (Mtb). In humans, CD8+ Mtb-reactive T cells have been described that are HLA-A2-, B52-, as well as CD1-restricted. Recently, we have described Mtb-specific CD8+ T cells that are neither HLA-A-, B-, or C- nor group 1 CD1-restricted. At present, little is known about the relative contribution of each of these restriction specificities to the overall CD8+ response to Mtb. An IFN-γ enzyme-linked immunospot assay was used to determine the frequency of Mtb-reactive CD8+ T cells directly from PBMC. The effector cell frequency among five healthy purified protein derivative-positive subjects was 1/7,600 ± 4,300 compared with 1/16,000 ± 7,000 in six purified protein derivative-negative controls. To determine the frequencies of classically, CD1-, and nonclassically restricted cells, a limiting dilution analysis was performed. In one purified protein derivative-positive subject, 192 clones were generated using Mtb-infected dendritic cells (DC). Clones were assessed for reactivity against control autologous DC, Mtb-infected autologous DC, and HLA-mismatched CD1+ targets (DC), as well as HLA-mismatched CD1− targets (macrophages). Of the 96 Mtb-reactive CD8+ T cell clones, four (4%) were classically restricted and 92 (96%) were nonclassically restricted. CD1-restricted cells were not detected. Of the classically restricted cells, two were HLA-B44 restricted and one was HLA-B14 restricted. These results suggest that while classically restricted CD8+ lymphocytes can be detected, they comprise a relatively small component of the overall CD8+ T cell response to Mtb. Further definition of the nonclassical response may aid development of an effective vaccine against tuberculosis.
Identification of NY-ESO-1 Peptide Analogues Capable of Improved Stimulation of Tumor-Reactive CTL
Authors: Chen Ji-Li , Dunbar P. Rod , Gileadi Uzi , Jäger Elke , Gnjatic Sacha , Nagata Yasuhiro , Stockert Elisabeth , Panicali Dennis L. , Chen Yao-Tseng , Knuth Alexander , Old Lloyd J. , Cerundolo Vincenzo 
Published: April 2014

AbstractExpression of NY-ESO-1 in a high proportion of different human tumors makes this protein a very attractive vaccine target. NY-ESO-1 peptides, recognized by HLA-A2-restricted CTL, have recently been described. However, it remains unclear how efficiently tumors generate these epitopes, and whether peptide analogues can be used for optimal expansion and activation of NY-ESO-1-specific HLA-A2-restricted CTL. By generating unique CTL clones, we demonstrate that NY-ESO-1-positive tumor cells are efficiently killed by HLA-A2-restricted CTL specific for the peptide epitope NY-ESO-1 157–165. Presentation of this epitope is not affected by the presence or absence of the proteasome subunits low molecular proteins 2 and 7 and is not blocked by proteasome inhibitors, while it is impaired in the TAP-deficient cell line LBL 721.174. NY-ESO-1 157–165 peptide analogues were compared for their antigenicity and immunogenicity using PBL from melanoma patients. Three peptides, containing the carboxyl-terminal cysteine substituted for either valine, isoleucine, or leucine, were recognized at least 100 times more efficiently than the wild-type peptide by specific CTL. Peptide analogues were capable of stimulating the expansion of NY-ESO-1-specific CTL from PBL of melanoma patients much more efficiently than wild-type peptide. These findings define the processing requirements for the generation of the NY-ESO-1 157–165 epitope. Identification of highly antigenic NY-ESO-1 peptide analogues may be important for the development of vaccines capable of expanding NY-ESO-1-specific CTL in cancer patients.
Macrophage Inflammatory Protein-1α Is a Critical Mediator of Host Defense Against Invasive Pulmonary Aspergillosis in Neutropenic Hosts
Authors: Mehrad Borna , Moore Thomas A. , Standiford Theodore J. 
Published: April 2014

AbstractInvasive pulmonary aspergillosis is a devastating complication of immunosuppression that usually occurs in neutropenic patients. In this setting, augmentation of the antifungal activity of available immune cells may improve the outcome of the infection. Macrophage inflammatory protein-1α (MIP-1α) is a CC chemokine with potent chemotactic activity for various subsets of mononuclear leukocytes. We therefore tested the hypothesis that the influx of mononuclear cells into the lung in invasive pulmonary aspergillosis is in part mediated by MIP-1α, and the manipulation of this ligand alters the outcome of the infection. We found that in both immunocompetent and neutropenic mice, MIP-1α was induced in the lungs in response to intratracheal administration of Aspergillus fumigatus conidia. In neutrophil-depleted mice challenged with intratracheal conidia, there was evidence of invasive fungal pneumonia associated with a predominantly mononuclear leukocyte infiltrate. Ab-mediated depletion of MIP-1α resulted in a 6-fold increase in mortality in neutropenic mice, which was associated with a 12-fold increase in lung fungal burden. Studies of single-cell suspensions of whole lungs revealed a 36% decrease in total lung leukocyte infiltration as a result of MIP-1α neutralization. Flow cytometry on whole lung suspensions showed a 41% reduction in lung monocyte/macrophages as a result of MIP-1α neutralization, but no difference in other lung leukocyte subsets. These studies indicate that MIP-1α is a critical mediator of host defense against A. fumigatus in the setting of neutropenia and may be an important target in devising future therapeutic strategies against invasive aspergillosis.
IL-10 Converts Human Dendritic Cells into Macrophage-Like Cells with Increased Antibacterial Activity Against VirulentMycobacterium tuberculosis
Authors: Förtsch Daniela , Röllinghoff Martin , Stenger Steffen 
Published: April 2014

AbstractDendritic cells (DC) are unique in their ability to initiate a primary immune response by the presentation of soluble Ags to T cells. Recent studies have shown that DC also phagocytose particulate Ags including the intracellular pathogen Mycobacterium tuberculosis. However, it is not known whether DC contain the growth of intracellular organisms or allow unlimited replication. To address this question, we infected human DC with a virulent strain of M. tuberculosis and monitored the intracellular growth. The bacteria grew two orders of magnitude within 7 days of culture. Among cytokines known to modulate mycobacterial growth particularly in murine macrophages (TNF-α, IFN-γ, TGF-β, IL-4), only IL-10 modulated the growth in human DC. This effect was specific for immature dendritic cells, as IL-10 did not induce growth inhibition in human macrophages. In searching for the mechanism of growth inhibition, we found that IL-10 induces the down-regulation of the DC marker CD1, while the macrophage marker CD14 was up-regulated. Functionally, IL-10-treated cells had a reduced capacity to induce an alloresponse, but phagocytic uptake of M. tuberculosis was more efficient. We also show that DC are inferior to macrophages in containing mycobacterial growth. These findings show that IL-10 converts DC into macrophage-like cells, thereby inducing the growth inhibition of an intracellular pathogen. At the site of a local immune response, such as a tuberculous granuloma, IL-10 might therefore participate in the composition of the cellular microenvironment by affecting the maturity and function of DC.
Nitric Oxide Induces Thymocyte Apoptosis Via a Caspase-1-Dependent Mechanism
Authors: Zhou Xin , Gordon Sherilyn A. , Kim Young-Myeong , Hoffman Rosemary A. , Chen Yue , Zhang Xiao-Ru , Simmons Richard L. , Ford Henri R. 
Published: April 2014

AbstractWe previously showed that NO induces apoptosis in thymocytes via a p53-dependent pathway. In the present study, we investigated the role of caspases in this process. The pan-caspase inhibitor, ZVAD-fmk, and the caspase-1 inhibitor, Ac-YVAD-cho, both inhibited NO-induced thymocyte apoptosis in a dose-dependent manner, whereas the caspase-3 inhibitor, Ac-DEVD-cho, had little effect even at concentrations up to 500 μM. ZVAD-fmk and Ac-YVAD-cho were able to inhibit apoptosis when added up to 12 h, but not 16 h, after treatment with the NO donor S-nitroso-N-acetyl penicillamine (SNAP). Caspase-1 activity was up-regulated at 4 h and 8 h and returned to baseline by 24 h; caspase-3 activity was not detected. Cytosolic fractions from SNAP-treated thymocytes cleaved the inhibitor of caspase-activated deoxyribonuclease. Such cleavage was completely blocked by Ac-YVAD-cho, but not by Ac-DEVD-cho or DEVD-fmk. Poly(ADP-ribose) polymerase (PARP) was also cleaved in thymocytes 8 h and 12 h after SNAP treatment; addition of Ac-YVAD-cho to the cultures blocked PARP cleavage. Furthermore, SNAP induced apoptosis in 44% of thymocytes from wild-type mice; thymocytes from caspase-1 knockout mice were more resistant to NO-induced apoptosis. These data suggest that NO induces apoptosis in thymocytes via a caspase-1-dependent but not caspase-3-dependent pathway. Caspase-1 alone can cleave inhibitor of caspase-activated deoxyribonuclease and lead to DNA fragmentation, thus providing a novel pathway for NO-induced thymocyte apoptosis.
Glycosyl-Phosphatidylinositol Reanchoring Unmasks Distinct Antigen-Presenting Pathways for CD1b and CD1c
Authors: Geho David H. , Fayen John D. , Jackman Robin M. , Moody D. Branch , Porcelli Steven A. , Tykocinski Mark L. 
Published: April 2014

Abstract
Human CD1 proteins present lipid and glycolipid Ags to T cells. Cellular trafficking patterns of CD1 proteins may determine the ability of differing isoforms of CD1 to acquire, bind, and present these Ags to T cells. To test this hypothesis, glycosyl-phosphatidylinositol (GPI)-modified variants of CD1b and CD1c were engineered by chimerization with a GPI modification signal sequence derived from decay-accelerating factor (DAF). GPI reanchoring was confirmed by demonstrating the phosphatidylinositol-specific phospholipase C sensitivity of the CD1b · DAF and CD1c · DAF fusion proteins expressed on transfectant cell surfaces. Using cytotoxicity and cytokine release assays as functional readouts, we demonstrated that CD1c · DAF is as efficient as native CD1c in presenting mycobacterial Ags to the human CD1c-restricted T cell line CD8-1. In contrast, CD1b · DAF, although also capable of presenting Ag (in this case to the CD1b-restricted T cell line LDN5), was less efficient than its native CD1b counterpart. The data support the idea that CD1c · DAF maintains the capacity to access CD1c Ag-loading compartment(s), whereas CD1b · DAF is diverted by its GPI anchor away from the optimal CD1b Ag-loading compartment(s). This constitutes the first GPI reanchoring of CD1 proteins and provides evidence that CD1b and CD1c have nonoverlapping Ag-presenting pathways, suggesting that these two Ag-presenting molecules may have distinct roles in lipid Ag presentation.
The Alloreactive and Self-Restricted CD4+ T Cell Response Directed Against a Single MHC Class II/Peptide Combination
Authors: Kovalik Jean-Paul , Singh Nagendra , Mendiratta Sanjeev K. , Martin W. David , Ignatowicz Leszek , Van Kaer Luc 
Published: April 2014

AbstractThe cellular basis for allograft rejection derives from the strong T cell response to cells bearing foreign MHC. While it was originally assumed that alloreactive T cells focus their recognition on the polymorphic residues that differ between syngeneic and allogeneic MHC molecules, studies with MHC class I-restricted CTL have shown that MHC-bound peptides play a critical role in allorecognition. It has been suggested that alloreactive T cells depend more strongly on interactions with the MHC molecule than with the associated peptide, but there is little evidence to support this idea. Here we have studied the alloreactive and self-restricted response directed against the class II H2-Ab molecule bound with a single peptide, Ep, derived from the H2-Eα chain. This MHC class II-peptide combination was a poor target and stimulator of alloreactive CD4+ T cell responses, indicating that MHC-bound peptides are as important for alloreactive CD4+ T cells as they are for alloreactive CTL. We also generated alloreactive T cells with exquisite specificity for the Ab/Ep complex, and compared their reactivity with self-restricted T cells specific for the same Ab/Ep complex. Our results showed that peptide-specific alloreactive T cells, as compared with self-restricted T cells, were more sensitive to peptide stimulation, but equally sensitive to amino acid substitutions in the peptide. These findings indicate that alloreactive and self-restricted T cells interact similarly with their MHC/peptide ligand.
Src Homology Region 2 (SH2) Domain-Containing Phosphatase-1 Dephosphorylates B Cell Linker Protein/SH2 Domain Leukocyte Protein of 65 kDa and Selectively Regulates c-Jun NH2-Terminal Kinase Activation in B Cells
Authors: Mizuno Kazuya , Tagawa Yuko , Mitomo Katsuyuki , Arimura Yutaka , Hatano Norikazu , Katagiri Tatsuo , Ogimoto Mami , Yakura Hidetaka 
Published: April 2014

AbstractSrc homology region 2 (SH2) domain-containing phosphatase-1 (SHP-1) is a cytosolic protein tyrosine phosphatase containing two SH2 domains in its NH2 terminus. That immunological abnormalities of the motheaten and viable motheaten mice are caused by mutations in the gene encoding SHP-1 indicates that SHP-1 plays important roles in lymphocyte differentiation, proliferation, and activation. To elucidate molecular mechanisms by which SHP-1 regulates BCR-mediated signal transduction, we determined SHP-1 substrates in B cells using the substrate-trapping approach. When the phosphatase activity-deficient form of SHP-1, in which the catalytic center cysteine (C453) was replaced with serine (SHP-1-C/S), was introduced in WEHI-231 cells, tyrosine phosphorylation of a protein of about 70 kDa was strongly enhanced. Immunoprecipitation and Western blot analyses revealed that this protein is the B cell linker protein (BLNK), also named SH2 domain leukocyte protein of 65 kDa, and that upon tyrosine phosphorylation BLNK binds to SHP-1-C/S in vitro. In vitro kinase assays demonstrated that hyperphosphorylation of BLNK in SHP-1-C/S-expressing cells was not due to enhanced activity of Lyn or Syk. Furthermore, BCR-induced activation of c-Jun NH2-terminal kinase was shown to be significantly enhanced in SHP-1-C/S transfectants. Taken collectively, our results suggest that BLNK is a physiological substrate of SHP-1 in B cells and that SHP-1 selectively regulates c-Jun NH2-terminal kinase activation.