bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synergy Between CD40 Ligation and IL-4 on Fibroblast Proliferation Involves IL-4 Receptor Signaling
Authors: Atamas Sergei P. , Luzina Irina G. , Dai Heqiao , Wilt Susan G. , White Barbara 
Published: April 2014

AbstractFibrosis can be an undesired consequence of activated cellular immune responses. The purpose of this work was to determine whether CD40 ligation and the pro-fibrotic cytokine IL-4 interact in regulating fibroblast proliferation and collagen production, and, if so, the mechanisms used. This study found that the combination of IL-4 and ligation of CD40 on the fibroblast cell surface had synergistic effects in stimulating fibroblast proliferation. In contrast, CD40 ligation negated the inhibitory effects of IFN-γ on fibroblast proliferation. Western blotting analyses of fibroblast crude lysates revealed that a potential mechanism of the synergy between CD40 ligation and IL-4 was the phosphorylation of proteins at 130 kDa and, to a lesser degree, at 95, 85, and 75 kDa. Immunoprecipitation-Western blotting experiments showed that phosphorylation levels of IL-4Rα, Janus kinase 1, insulin receptor substrate 1, and insulin receptor substrate 2, factors with molecular mass close to the observed 130 kDa major phosphorylation band, increased in response to the combined CD40 ligation and IL-4 action. In contrast, there was no evidence that synergy was mediated by an increased expression of IL-4Rα chain, CD40, or the autocrine profibrotic cytokines IL-6 and TGF-β. These findings suggest that CD40-CD40 ligand contacts between fibroblasts and cells secreting IL-4 may promote the profibrotic effects of IL-4 by affecting signal transduction and reducing the anti-fibrotic effects of IFN-γ.
Functional Avidity of Tumor Antigen-Specific CTL Recognition Directly Correlates with the Stability of MHC/Peptide Multimer Binding to TCR
Authors: Dutoit Valérie , Rubio-Godoy Verena , Doucey Marie-Agnès , Batard Pascal , Liénard Danielle , Rimoldi Donata , Speiser Daniel , Guillaume Philippe , Cerottini Jean-Charles , Romero Pedro , Valmori Danila 
Published: April 2014

AbstractAvidity of Ag recognition by tumor-specific T cells is one of the main parameters that determines the potency of a tumor rejection Ag. In this study we show that the relative efficiency of staining of tumor Ag-specific T lymphocytes with the corresponding fluorescent MHC class I/peptide multimeric complexes can considerably vary with staining conditions and does not necessarily correlate with avidity of Ag recognition. Instead, we found a clear correlation between avidity of Ag recognition and the stability of MHC class I/peptide multimeric complexes interaction with TCR as measured in dissociation kinetic experiments. These findings are relevant for both identification and isolation of tumor-reactive CTL.
Induction of MHC Class I Presentation of Exogenous Antigen by Dendritic Cells Is Controlled by CD4+ T Cells Engaging Class II Molecules in Cholesterol-Rich Domains
Authors: Machy Patrick , Serre Karine , Baillet Marjorie , Leserman Lee 
Published: April 2014

AbstractWe investigated interactions between CD4+ T cells and dendritic cells (DC) necessary for presentation of exogenous Ag by DC to CD8+ T cells. CD4+ T cells responding to their cognate Ag presented by MHC class II molecules of DC were necessary for induction of CD8+ T cell responses to MHC class I-associated Ag, but their ability to do so depended on the manner in which class II-peptide complexes were formed. DC derived from short-term mouse bone marrow culture efficiently took up Ag encapsulated in IgG FcR-targeted liposomes and stimulated CD4+ T cell responses to Ag-derived peptides associated with class II molecules. This CD4+ T cell-DC interaction resulted in expression by the DC of complexes of class I molecules and peptides from the Ag delivered in liposomes and permitted expression of the activation marker CD69 and cytotoxic responses by naive CD8+ T cells. However, while free peptides in solution loaded onto DC class II molecules could stimulate IL-2 production by CD4+ T cells as efficiently as peptides derived from endocytosed Ag, they could not stimulate induction of cytotoxic responses by CD8+ T cells to Ag delivered in liposomes into the same DC. Signals requiring class II molecules loaded with endocytosed Ag, but not free peptide, were inhibited by methyl-β-cyclodextrin, which depletes cell membrane cholesterol. CD4+ T cell signals thus require class II molecules in cholesterol-rich domains of DC for induction of CD8+ T cell responses to exogenous Ag by inducing DC to process this Ag for class I presentation.
1,25-Dihydroxyvitamin D3 Inhibits IFN-γ and IL-4 Levels During In Vitro Polarization of Primary Murine CD4+ T Cells
Authors: Staeva-Vieira Teodora P. , Freedman Leonard P. 
Published: April 2014

AbstractFollowing their activation, naive CD4+ T cells can differentiate into one of two effector cell subsets, Th1 and Th2. These two subsets have different cytokine secretion patterns and thus mediate separate arms of the immune response. It has been established that the fat-soluble vitamin D3 metabolite 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and its nuclear receptor, the vitamin D receptor, play an important role in the immune system primarily through the transcriptional inhibition of cytokine genes that either are required for Th1 differentiation or are products of differentiated Th1 cells. Therefore, we wanted to test directly the ability of 1,25(OH)2D3 to alter the Th differentiation process. Our results indicate that 1,25(OH)2D3 inhibits not only the Th1 cytokine IFN-γ but also the Th2 cytokine IL-4 in naive CD62 ligand+CD4+ T cells during their in vitro polarization. This effect is most dramatic when the ligand is present from the onset of the differentiation process. If the ligand is added after the polarization has ensued, the inhibition is significantly diminished. In activated (CD62 ligand−CD4+) T cells, 1,25(OH)2D3 is still able to inhibit IFN-γ but has no effect on IL-4 production. Our results also indicate that inhibition of these two cytokines in naive cells by vitamin D receptor and its ligand is neither a result of a cell cycle block nor an inhibition of Th1 or Th2 transcription factor expression but, rather, at least in the case of Th2 differentiation, an attenuation of IL-4 transcription by the receptor.
Activation-Induced Nonresponsiveness: A Th-Dependent Regulatory Checkpoint in the CTL Response
Authors: Tham Ee Loon , Shrikant Protul , Mescher Matthew F. 
Published: April 2014

AbstractCD8 T cells undergo autocrine IL-2-dependent proliferation upon TCR engagement and costimulation, but within 3–4 days, they become activation-induced nonresponsive (AINR) and display a split anergy. They can lyse targets and secrete IFN-γ but they cannot produce IL-2 in response to TCR ligation and costimulation, due at least in part to an inability to up-regulate mitogen-activated protein kinases and IL-2 mRNA. Exogenous IL-2 can drive continued proliferation of AINR cells and nonresponsiveness is reversed within 1–2 days so that Ag-driven proliferation can resume. Mitogen-activated protein kinases and IL-2 mRNA can again be up-regulated, but “rewiring” has occurred so that these events no longer depend upon costimulation; TCR engagement is sufficient. Development of AINR appears to be a normal part of the differentiation program of CD8 T cells, providing a regulatory checkpoint to convert the initial helper-independent response to one that depends upon CD4 T cell help for continued expansion of the effector CTL. Once permission is given, in the form of IL-2, to pass this checkpoint, the CTL can make a prolonged response to persisting Ag in the absence of further CD4 T cell help.
Overexpression of IL-15 In Vivo Increases Antigen-Driven Memory CD8+ T Cells Following a Microbe Exposure
Authors: Yajima Toshiki , Nishimura Hitoshi , Ishimitsu Ryotaro , Watase Taketo , Busch Dirk H. , Pamer Eric G. , Kuwano Hiroyuki , Yoshikai Yasunobu 
Published: April 2014

AbstractTo elucidate potential roles of IL-15 in the maintenance of memory CD8+ T cells, we followed the fate of Ag-specific CD8+ T cells directly visualized with MHC class I tetramers coupled with listeriolysin O (LLO)91–99 in IL-15 transgenic (Tg) mice after Listeria monocytogenes infection. The numbers of LLO91–99-positive memory CD8+ T cells were significantly higher at 3 and 6 wk after infection than those in non-Tg mice. The LLO91–99-positive CD8+ T cells produced IFN-γ in response to LLO91–99, and an adoptive transfer of CD8+ T cells from IL-15 Tg mice infected with L. monocytogenes conferred a higher level of resistance against L. monocytogenes in normal mice. The CD44+CD8+ T cells from infected IL-15 Tg mice expressed the higher level of Bcl-2. Transferred CD44+CD8+ T cells divided more vigorously in naive IL-15 Tg mice than in non-Tg mice. These results suggest that IL-15 plays an important role in long-term maintenance of Ag-specific memory CD8+ T cells following microbial exposure via promotion of cell survival and homeostatic proliferation.
Characterization of a Conformationally Sensitive Murine Monoclonal Antibody Directed to the Metal Ion-Dependent Adhesion Site Face of Integrin CD11b
Authors: Li Rui , Haruta Ikuko , Rieu Philippe , Sugimori Takashi , Xiong Jian-Ping , Arnaout M. Amin 
Published: April 2014

AbstractIntegrin binding to physiologic ligands requires divalent cations and an inside-out-driven switch of the integrin to a high-affinity state. Divalent cations at the metal ion-dependent adhesion site (MIDAS) face of the α subunit-derived A domain provide a direct bridge between ligands and the integrin, and it has been proposed that activation dependency is caused by reorientation of the surrounding residues relative to the metal ion, forming an optimal binding interface. To gain more insight into the functional significance of the protein movements on the MIDAS face, we raised and characterized a murine mAb 107 directed against the MIDAS face of the A domain from integrin CD11b. We find that mAb 107 behaves as a ligand mimic. It binds in a divalent-cation-dependent manner to solvent-exposed residues on the MIDAS face of CD11b, blocks interaction of 11bA or the holoreceptor with ligands, and inhibits spreading and phagocytosis by human neutrophils. However, in contrast to physiologic ligands, mAb 107 preferentially binds to the inactive low-affinity form of the integrin, suggesting that its antagonistic effects are exerted in part by stabilizing the receptor in the low-affinity state. These data support a functional relevance of the protein movements on the MIDAS face and suggest that stabilizing the A domain in the low-affinity state may have therapeutic benefit.
In APCs, the Autologous Peptides Selected by the Diabetogenic I-Ag7 Molecule Are Unique and Determined by the Amino Acid Changes in the P9 Pocket
Authors: Suri Anish , Vidavsky Ilan , van der Drift Koen , Kanagawa Osami , Gross Michael L. , Unanue Emil R. 
Published: April 2014

AbstractWe demonstrate in this study the great degree of specificity in peptides selected by a class II MHC molecule during processing. In this specific case of the diabetogenic I-Ag7 molecule, the P9 pocket of I-Ag7 plays a critical role in determining the final outcome of epitope selection, a conclusion that is important in interpreting the role of this molecule in autoimmunity. Specifically, we examined the display of naturally processed peptides from APCs expressing either I-Ag7 molecules or a mutant I-Ag7 molecule in which the β57Ser residue was changed to an Asp residue. Using mass spectrometry analysis, we identified over 50 naturally processed peptides selected by I-Ag7-expressing APCs. Many peptides were selected as families with a core sequence and variable flanks. Peptides selected by I-Ag7 were unusually rich in the presence of acidic residues toward their C termini. Many peptides contained short sequences of two to three acidic residues. In binding analysis, we determined the core sequences of many peptides and the interaction of the acidic residues with the P9 pocket. However, different sets of peptides were isolated from APCs bearing a modified I-Ag7 molecule. These peptides did not favor acidic residues toward the carboxyl terminus.
Matrix Metalloproteinase-19 Is Expressed in Myeloid Cells in an Adhesion-Dependent Manner and Associates with the Cell Surface
Authors: Mauch Simon , Kolb Cornelia , Kolb Birgit , Sadowski Thorsten , Sedlacek Radislav 
Published: April 2014

AbstractWe have previously reported the isolation of the human matrix metalloproteinase (MMP)-19 (also referred to as RASI) from a synovium of a patient suffering from rheumatoid arthritis and its expression at the cell surface of activated PBMC. In this study, we have analyzed the regulation and cell surface expression of human MMP-19 in several human cell lines and blood-derived cells. Among the cell lines analyzed, MMP-19 is largely expressed by lung fibroblasts as well as by myeloid cell lines THP-1 and HL-60. After fractionating PBMC into CD14− and CD14+ populations we found that only the latter one expresses MMP-19. Although the myeloid cell lines as well as CD14+ cells express MMP-19 without stimulation, its production can be up-regulated by phorbol esters (PMA) or by adhesion. The adhesion-dependent expression was down-regulated or even abrogated by blockade of adhesion or interfering with adhesion-controlling signaling using α-tocopherol. We have shown that MMP-19 associates with the cell surface of myeloid cells. This cell surface association was not affected by phospholipase C. However, acidic treatment of the THP-1-derived cell membranes abolished the immunoprecipitation of MMP-19 thereof. Moreover, a high salt treatment of THP-1 cells diminished the MMP-19 detection on the cell surface. This implicates a noncovalent attachment of MMP-19 to the cell surface. Because a truncated form of the MMP-19, in which the hemopexin-like domain was deleted (ΔhpMMP-19), does not associate with the surface, the hemopexin-like domain appears to be critical for the cell surface attachment of human MMP-19.
Comparison of the Crystal Structures of the Human Manganese Superoxide Dismutase and the Homologous Aspergillus fumigatus Allergen at 2-Å Resolution
Authors: Flückiger Sabine , Mittl Peer R. E. , Scapozza Leonardo , Fijten Helmi , Folkers Gerd , Grütter Markus G. , Blaser Kurt , Crameri Reto 
Published: April 2014

Abstract
Manganese superoxide dismutase (MnSOD) of Aspergillus fumigatus, a fungus involved in many pulmonary complications, has been identified as IgE-binding protein. It has been shown also that MnSODs from other organisms, including human, are recognized by IgE Abs from individuals sensitized to A. fumigatus MnSOD. Comparison of the fungal and the human crystal structure should allow the identification of structural similarities responsible for IgE-mediated cross-reactivity. The three-dimensional structure of A. fumigatus MnSOD has been determined at 2-Å resolution by x-ray diffraction analysis. Crystals belonged to space group P212121 with unit cell dimensions of a = 65.88 Å, b = 98.7 Å, and c = 139.28 Å. The structure was solved by molecular replacement using the structure of the human MnSOD as a search model. The final refined model included four chains of 199–200 amino acids, four manganese ions, and 745 water molecules, with a crystallographic R-factor of 19.4% and a free R-factor of 23.3%. Like MnSODs of other eukaryotic organisms, A. fumigatus MnSOD forms a homotetramer with the manganese ions coordinated by three histidines, one aspartic acid, and one water molecule. The fungal and the human MnSOD share high similarity on the level of both primary and tertiary structure. We identified conserved amino acids that are solvent exposed in the fungal and the human crystal structure and are therefore potentially involved in IgE-mediated cross-reactivity.
T15-Idiotype-Negative B Cells Dominate the Phosphocholine Binding Cells in the Preimmune Repertoire of T15i Knockin Mice
Authors: Hu Lina , Rezanka Louis J. , Mi Qing-Sheng , Lustig Ana , Taub Dennis D. , Longo Dan L. , Kenny James J. 
Published: April 2014

AbstractT15i knockin (KI) mice express a H chain that is encoded by a rearranged T15 VDJ transgene which has been inserted into the JH region of chromosome 12. This T15H chain combines with a κ22–33 L chain to produce a T15-Id+ Ab having specificity for phosphocholine (PC). Inasmuch as T15-Id+ Abs dominate the primary immune response to PC in normal mice, it was surprising to find that 80% of the PC-dextran-binding B cells in unimmunized homozygous T15i KI mice were T15-Id−. Analysis of L chains expressed in these T15-Id−, PC-specific B cells revealed that two L chains, κ8–28 and κ19–15, were expressed in this population. The Vκ region of these L chains was recombined to Jκ5, which is typical of L chains present in PC-specific Abs. When T15i KI mice were immunized with PC Ag, T15-Id+ B cells expanded 6-fold and differentiated into Ab-secreting cells. There was no indication that the T15-Id− B cells either proliferated or differentiated into Ab-secreting cells following immunization. Thus, T15-Id− B cells dominate the PC-binding population, but they fail to compete with T15-Id+ B cells during a functional immune response. Structural analysis of T15H:κ8–28L and T15H:κ19–15L Abs revealed L chain differences from the κ22–33 L chain which could account for the lower affinity and/or avidity of these Abs for PC or PC carrier compared with the T15-Id+ T15H:κ22–33L Ab.
The Ability of Variant Peptides to Reverse the Nonresponsiveness of T Lymphocytes to the Wild-Type Sequence p53264–272 Epitope
Authors: Hoffmann Thomas K. , Loftus Douglas J. , Nakano Koji , Maeurer Markus J. , Chikamatsu Kazuaki , Appella Ettore , Whiteside Theresa L. , DeLeo Albert B. 
Published: April 2014

AbstractRecently, we observed that CTL specific for the wild-type (wt) sequence p53264–272 peptide could only be expanded ex vivo from PBMC of a subset of the HLA-A2.1+ normal donors or cancer patients tested. Surprisingly, the tumors of the responsive patients expressed normal levels of wt p53 and could be considered unlikely to present this epitope. In contrast, tumors of nonresponsive patients accumulated mutant p53 and were more likely to present this epitope. We sought to increase the responsive rate to the wt p53264–272 peptide of PBMC obtained from normal donors and patients by identifying more immunogenic variants of this peptide. Two such variants were generated by amino acid exchanges at positions 6 (6T) and 7 (7W) of the peptide. These variants were capable of inducing T cells from PBMC of nonresponsive donors that recognized the parental peptide either pulsed onto target cells or naturally presented by tumors. TCR Vβ analysis of two T cell lines isolated from bulk populations of effectors reactive against the wt p53264–272 peptide, using either the parental or the 7W variant peptide, indicated that these T cells were expressing identical TCR Vβ13.6/complementarity-determining region 3/J region sequences. This finding confirms the heteroclitic nature of at least one of the variant peptides identified in this study. The use of variant peptides of the wt p53264–272 epitope represents a promising approach to overcoming the nonresponsiveness of certain cancer patients to this self epitope, thereby enhancing its potential use in tumor vaccines for appropriately selected cancer patients.
IL-12 Is Required for Antibody-Mediated Protective Immunity Against Blood-StagePlasmodium chabaudiAS Malaria Infection in Mice
Authors: Su Zhong , Stevenson Mary M. 
Published: April 2014

AbstractIn this study, we investigated the role of endogenous IL-12 in protective immunity against blood-stage P. chabaudi AS malaria using IL-12 p40 gene knockout (KO) and wild-type (WT) C57BL/6 mice. Following infection, KO mice developed significantly higher levels of primary parasitemia than WT mice and were unable to rapidly resolve primary infection and control challenge infection. Infected KO mice had severely impaired IFN-γ production in vivo and in vitro by NK cells and splenocytes compared with WT mice. Production of TNF-α and IL-4 was not compromised in infected KO mice. KO mice produced significantly lower levels of Th1-dependent IgG2a and IgG3 but a higher level of Th2-dependent IgG1 than WT mice during primary and challenge infections. Treatment of KO mice with murine rIL-12 during the early stage of primary infection corrected the altered IgG2a, IgG3, and IgG1 responses and restored the ability to rapidly resolve primary and control challenge infections. Transfer of immune serum from WT mice to P. chabaudi AS-infected susceptible A/J mice completely protected the recipients, whereas immune serum from KO mice did not, as evidenced by high levels of parasitemia and 100% mortality in recipient mice. Furthermore, depletion of IgG2a from WT immune serum significantly reduced the protective effect of the serum while IgG1 depletion had no significant effect. Taken together, these results demonstrate the protective role of a Th1-immune response during both acute and chronic phases of blood-stage malaria and extend the immunoregulatory role of IL-12 to Ab-mediated immunity against Plasmodium parasites.
Dendritic Cells Transport Conidia and Hyphae ofAspergillus fumigatusfrom the Airways to the Draining Lymph Nodes and Initiate Disparate Th Responses to the Fungus
Authors: Bozza Silvia , Gaziano Roberta , Spreca Antonio , Bacci Angela , Montagnoli Claudia , di Francesco Paolo , Romani Luigina 
Published: April 2014

AbstractAspergilli are respiratory pathogens and pulmonary infections are usually acquired through the inhalation of conidia, able to reach small airways and the alveolar space where the impaired host defense mechanisms allow hyphal germination and subsequent tissue invasion. The invasive pulmonary aspergillosis is the most common manifestation of Aspergillus fumigatus infection in immunocompromised patients and is characterized by hyphal invasion and destruction of pulmonary tissue. A Th1/Th2 dysregulation and a switch to a Th2 immune response may contribute to the development and unfavorable outcome of invasive pulmonary aspergillosis. Dendritic cells (DC) have a primary role in surveillance for pathogens at the mucosal surfaces and are recognized as the initiators of immune responses to them. In the present study, we assessed the functional activity of pulmonary DC in response to A. fumigatus conidia and hyphae, both in vitro and in vivo. We analyzed mechanisms and receptors for phagocytosis by DC as well as DC migration, maturation, and Th priming in vivo upon exposure to either form of the fungus. We found a remarkable functional plasticity of DC in response to the different forms of the fungus, as pulmonary DC were able to: 1) internalize conidia and hyphae of A. fumigatus through distinct phagocytic mechanisms and recognition receptors; 2) discriminate between the different forms in terms of cytokine production; 3) undergo functional maturation upon migration to the draining lymph nodes and spleens; and 4) instruct local and peripheral Th cell reactivity to the fungus.