bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultraviolet Irradiation Suppresses T Cell Activation via Blocking TCR-Mediated ERK and NF-κB Signaling Pathways
Authors: Li-Weber Min , Treiber Monika K. , Giaisi Marco , Palfi Katalin , Stephan Nadja , Parg Simone , Krammer Peter H.
Published: April 2014

UV irradiation is carcinogenic and immunosuppressive. Previous studies indicate that UV-mediated alteration of APCs and induction of suppressor T cells play a critical role in UV-induced immune suppression. In this study, we show that UV irradiation can directly (independently of APCs and suppressor T cells) inhibit T cell activation by blocking TCR-mediated phosphorylation of ERK and IκB via overactivation of the p38 and JNK pathways. These events lead to the down-modulation of c-Jun, c-Fos, Egr-1, and NF-κB transcription factors and thereby inhibit production of cytokines, e.g., IL-2, IL-4, IFN-γ, and TNF-α, upon TCR stimulation. We also show that UV irradiation can suppress preactivated T cells, indicating that UV irradiation does not only impair T cell function in response to T cell activation, but can also have systemic effects that influence ongoing immune responses. Thus, our data provide an additional mechanism by which UV irradiation directly suppresses immune responses.
Characteristics of NK Cell Migration Early after Vaccinia Infection
Authors: Prlic Martin , Gibbs James , Jameson Stephen C.
Published: April 2014

NK cells are critical components in innate immunity, yet little is known about their migration and proliferation during infection. In this report we study the early NK response toward vaccinia. We observed NK migration into the infected peritoneum as early as 6 h after vaccinia inoculation. Interestingly, although NK trafficking to the infected peritoneum depended on Gαi protein-coupled receptors, trafficking to other tissues (including lung, liver, spleen, and bone marrow) did not. We found that despite a dramatic increase in NK numbers at the primary site of infection, their in situ proliferation was low compared with that at other tissue locations. These features are similar to those found for Ag-experienced T cells, suggesting similar patterns of trafficking and proliferation for these lymphocyte subsets.
Rituximab-Induced Inhibition of YY1 and Bcl-xL Expression in Ramos Non-Hodgkin’s Lymphoma Cell Line via Inhibition of NF-κB Activity: Role of YY1 and Bcl-xL in Fas Resistance and Chemoresistance, Respectively
Authors: Vega Mario I. , Jazirehi Ali R. , Huerta-Yepez Sara , Bonavida Benjamin
Published: April 2014

Rituximab treatment of B non-Hodgkin’s lymphoma (NHL) cell lines inhibits the constitutive NF-κB activity and results in the sensitization of tumor cells to both chemotherapy and Fas-induced apoptosis. Cells expressing dominant active IκB or treated with NF-κB-specific inhibitors were sensitive to both drugs and Fas agonist mAb (CH-11)-induced apoptosis. Down-regulation of Bcl-xL expression via inhibition of NF-κB activity correlated with chemosensitivity. The direct role of Bcl-xL in chemoresistance was demonstrated by the use of Bcl-xL-overexpressing Ramos cells, Ramos hemagglutinin (HA)-Bcl-x, which were not sensitized by rituximab to drug-induced apoptosis. However, inhibition of Bcl-xL in Ramos HA-Bcl-x resulted in sensitization to drug-induced apoptosis. The role of Bcl-xL expression in the regulation of Fas resistance was not apparent; Ramos HA-Bcl-x cells were as sensitive as the wild type to CH-11-induced apoptosis. Several lines of evidence support the direct role of the transcription repressor yin-yang 1 (YY1) in the regulation of resistance to CH-11-induced apoptosis. Inhibition of YY1 activity by either rituximab or the NO donor DETANONOate or after transfection with YY1 small interfering RNA resulted in up-regulation of Fas expression and sensitization to CH-11-induced apoptosis. These findings suggest two mechanisms underlying the chemosensitization and immunosensitization of B-NHL cells by rituximab via inhibition of NF-κB. The regulation of chemoresistance by NF-κB is mediated via Bcl-xL expression, whereas the regulation of Fas resistance by NF-κB is mediated via YY1 expression and activity. The potential clinical significance of these findings is discussed.
T Cell Tolerance to Germline-Encoded Antibody Sequences in a Lupus-Prone Mouse
Authors: Guo Wenzhong , Smith Diana , Guth Amanda , Aviszus Katja , Wysocki Lawrence J.
Published: April 2014

The BCR V region has been implicated as a potential avenue of T cell help for autoreactive B cells in systemic lupus erythematosus. In principle, either germline-encoded or somatically generated sequences could function as targets of such help. Preceding studies have indicated that class II MHC-restricted T cells in normal mice attain a state tolerance to germline-encoded Ab diversity. In this study, we tested whether this tolerance is intact in systemic lupus erythematosus-prone (New Zealand Black × SWR)F1 mice (SNF1). Using a hybridoma sampling approach, we found that SNF1 T cells were tolerant to germline-encoded Ab sequences. Specifically, they were tolerant to germline-encoded sequences derived from a lupus anti-chromatin Ab that arose spontaneously in this strain. This was true both for diseased and prediseased mice. Thus, there does not appear to be a global defect in T cell tolerance to Ab V regions in this autoimmune-prone strain either before or during autoimmune disease.
Signaling Lymphocyte Activation Molecule-Associated Protein Is a Negative Regulator of the CD8 T Cell Response in Mice
Authors: Chen Gang , Tai Albert K. , Lin Miao , Chang Francesca , Terhorst Cox , Huber Brigitte T.
Published: April 2014

The primary manifestation of X-linked lymphoproliferative syndrome, caused by a dysfunctional adapter protein, signaling lymphocyte activation molecule-associated protein (SAP), is an excessive T cell response upon EBV infection. Using the SAP−/− mouse as a model system for the human disease, we compared the response of CD8+ T cells from wild-type (wt) and mutant mice to various stimuli. First, we observed that CD8+ T cells from SAP−/− mice proliferate more vigorously than those from wt mice upon CD3/CD28 cross-linking in vitro. Second, we analyzed the consequence of SAP deficiency on CTL effector function and homeostasis. For this purpose, SAP−/− and wt mice were infected with the murine γ-herpesvirus 68 (MHV-68). At 2 wk postinfection, the level of viral-specific CTL was much higher in mutant than in wt mice, measured both ex vivo and in vivo. In addition, we established that throughout 45 days of MHV-68 infection the frequency of virus-specific CD8+ T cells producing IFN-γ was significantly higher in SAP−/− mice. Consequently, the level of latent infection by MHV-68 was considerably lower in SAP−/− mice, which indicates that SAP−/− CTL control this infection more efficiently than wt CTL. Finally, we found that the Vβ4-specific CD8+ T cell expansion triggered by MHV-68 infection is also enhanced and prolonged in SAP−/− mice. Taken together, our data indicate that SAP functions as a negative regulator of CD8+ T cell activation.
Insertion of the Dibasic Motif in the Flanking Region of a Cryptic Self-Determinant Leads to Activation of the Epitope-Specific T Cells
Authors: Zhu Hui , Liu Kechang , Cerny Jan , Imoto Taiji , Moudgil Kamal D.
Published: April 2014

Efficient induction of self tolerance is critical for avoiding autoimmunity. The T cells specific for the well-processed and -presented (dominant) determinants of a native self protein are generally tolerized in the thymus, whereas those potentially directed against the inefficiently processed and presented (cryptic) self epitopes escape tolerance induction. We examined whether the crypticity of certain determinants of mouse lysozyme-M (ML-M) could be attributed to the nonavailability of a proteolytic site, and whether it could be reversed to immunodominance by engraftment of a novel cleavage site in the flanking region of the epitope. Using site-directed mutagenesis, we created the dibasic motif (RR or RK; R = arginine, K = lysine), a target of intracellular proteases, in the region adjoining one of the three cryptic epitopes (46–61, 66–79, or 105–119) of ML-M. Interestingly, the mutated lysozyme proteins, but not unmutated ML-M, were immunogenic in mice. The T cell response to the altered lysozyme was attributable to the efficient processing and presentation of the previously cryptic epitope, and this response was both epitope and MHC haplotype specific. In addition, the anti-self T cell response was associated with the generation of autoantibodies against self lysozyme. However, the results using one of three mutated lysozymes suggested that the naturally processed, dibasic motif-marked epitope may not always correspond precisely to the cryptic determinant within a synthetic peptide. This is the first report describing the circumvention of self tolerance owing to the targeted reversal of crypticity to dominance in vivo of a specific epitope within a native self Ag.
Resistance to Myelin Oligodendrocyte Glycoprotein-Induced Experimental Autoimmune Encephalomyelitis by Death Receptor 6-Deficient Mice
Authors: Schmidt Clint S. , Zhao Jingyong , Chain Jana , Hepburn Deena , Gitter Bruce , Sandusky George , Chintalacharuvu Subba , Glasebrook Andrew , Na Songqing
Published: April 2014

Genetic disruption of death receptor 6 (DR6) results in enhanced CD4+ T cell expansion, Th2 differentiation, and humoral responses after stimulation. However, the in vivo consequences of DR6 targeting (DR6−/−) during the initiation and progression of inflammatory autoimmune disease are unclear. Using a myelin oligodendrocyte glycoprotein (MOG35–55)-induced model of experimental autoimmune encephalomyelitis, DR6−/− mice were found to be highly resistant to both the onset and the progression of CNS disease compared with wild-type (WT) littermates. DR6−/− mice exhibited fewer inflammatory foci along with minimal demyelination and perivascular cuffing of inflammatory cells. Consistent with these observations, mononuclear cell infiltration, including CD4+ T cells and macrophages, in the spinal cord of DR6−/− mice was dramatically reduced. Furthermore, CD4+ T cells from DR6−/− mice exhibited profoundly reduced cell surface expression of VLA-4 before and after stimulation. Compared with WT mice, DR6−/− mice exhibited significantly increased autoantigen-induced T cell proliferative responses along with greater numbers of IL-4-producing and similar or slightly higher numbers of IFN-γ-producing CD4+ T cells. DR6−/− CD4+ T cells secreted higher levels of the Th2 cytokine, IL-4, and similar levels of the Th1 cytokine, IFN-γ, compared with WT cells. Taken together, our data demonstrate that DR6 plays an important role in regulating leukocyte infiltration and function in the induction and progression of experimental autoimmune encephalomyelitis.
Characterization of the Murine Immunological Signaling Network with Phosphospecific Flow Cytometry
Authors: Krutzik Peter O. , Hale Matthew B. , Nolan Garry P.
Published: April 2014

The immune system is a multitiered network that at the first level uses changes to intracellular signaling proteins to commit cells to determined fates. At the second tier, cells interact with one another via specifically expressed surface receptors and their cognate signaling molecules. At the third level, the local environments of immune cells change the outcomes of intracellular signaling pathways and thereby the role of cells during immune challenge. The interplay among these three tiers allows the distinct cell types of the immune system to respond cohesively to eliminate foreign Ags. In this study, using phosphospecific flow cytometry, we analyze elements of these network tiers by generating profiles of single-cell phosphoprotein responses in B cells, T cells, and myeloid cells to a number of mechanistically and clinically relevant cytokines (IFN-γ, GM-CSF, IL-2, and IL-10) as well as LPS at key regulatory interfaces (Jak-Stat and MAPK pathways). The stimuli typically induced phosphorylation of specific signaling pathways and exerted their effects on distinct subsets of immune cells. However, upon comparison of stimulation in vitro and in vivo, we noted that signaling pathway specificity and cell type specificity were influenced strongly by the external environment. When taken from the in vivo environment, certain cell subsets became hypo- or hyper-responsive, showed profound differences in sensitivity to cytokine levels, or displayed altered phosphorylation kinetics. Thus, simultaneous analysis of the three tiers of the immune system network illustrates the principles by which immune regulation is context dependent and how in vitro culture systems compare with the in vivo environment.
Demonstration of Autoimmunity in the Tight Skin-2 Mouse: A Model for Scleroderma
Authors: Gentiletti Julieta , McCloskey Laura J. , Artlett Carol M. , Peters Josephine , Jimenez Sergio A. , Christner Paul J.
Published: April 2014

The tight skin-2 (Tsk2/+) mouse has been proposed as an animal model of systemic sclerosis (SSc) because this animal exhibits increased collagen synthesis and accumulation in the dermis. The Tsk2/+ mouse also has been reported to have a mononuclear cell infiltrate in the dermis; however, to date no evidence of autoimmunity has been described in this animal model. We report here that Tsk2/+ mice harbor numerous autoantibodies in their plasma including some, which are similar to those, present in SSc patients. Immunofluorescence with HEp-2 cells revealed the presence of anti-nuclear Abs (ANAs) in the plasma of 92% of the Tsk2/+ mice. In contrast, <5% of cage-mated CAST/ei mice had a positive ANA and none of the C3H/HeJ age-matched controls were positive. Homogenous, speckled, rim, nucleolar, centromere as well as combinations of these patterns were observed. The proportion of Tsk2/+ animals with a positive ANA increased slightly with age. ELISAs showed that 93% of the Tsk2/+ animals were positive for anti-Scl70, 82% for anti-centromere, 5% for anti-RNP/Sm, and none were positive for anti-RNA-polymerase II Abs. Indirect immunofluorescence with Crithidia luciliae and ELISA for anti-dsDNA Abs showed that 76% of Tsk2/+ mice were positive for this autoantibody. The high frequency of anti-Scl70 and anti-centromere autoantibodies indicates that Tsk2/+ mice display some humoral immune alterations which are similar to those found in patients with SSc. However, the Tsk2/+ mice also develop autoantibodies to dsDNA and a majority of the mice develop multiple autoantibody specificities (anti-Scl70, anti-CENP-B, and anti-dsDNA) indicating that the mouse may be a useful model to study autoimmunity in a wider spectrum of connective tissue diseases.
Structures of Three HIV-1 HLA-B*5703-Peptide Complexes and Identification of Related HLAs Potentially Associated with Long-Term Nonprogression
Authors: Stewart-Jones Guillaume B. E. , Gillespie Geraldine , Overton Ian M. , Kaul Rupert , Roche Philippe , McMichael Andrew J. , Rowland-Jones Sarah , Jones E. Yvonne
Published: April 2014

Long-term nonprogression during acute HIV infection has been strongly associated with HLA-B*5701 or HLA-B*5703. In this study, we present the high resolution crystal structures of HLA-B*5703 complexes with three HIV-1 epitopes: ISPRTLNAW (ISP), KAFSPEVIPMF (KAF-11), and KAFSPEVI (KAF-8). These reveal peptide anchoring at position 2 and their C termini. The different peptide lengths and primary sequences are accommodated by variation in the specific contacts made to the HLA-B*5703, flexibility in water structure, and conformational adjustment of side chains within the peptide-binding groove. The peptides adopt markedly different conformations, and trap variable numbers of water molecules, near a cluster of tyrosine side chains located in the central region of the peptide-binding groove. The KAF-11 epitope completely encompasses the shorter KAF-8 epitope but the peptides are presented in different conformations; the KAF-11 peptide arches out of the peptide-binding groove, exposing a significant main chain surface area. Bioinformatic analysis of the MHC side chains observed to contribute to the peptide anchor specificity, and other specific peptide contacts, reveals HLA alleles associated with long-term nonprogression and a number of related HLA alleles that may share overlapping peptide repertoires with HLA-B*5703 and thus may display a similar capacity for efficient immune control of HIV-1 infection.
The Induction of a Type 1 Immune Response following a Trypanosoma brucei Infection Is MyD88 Dependent
Authors: Drennan Michael B. , Stijlemans Benoît , Van Den Abbeele Jan , Quesniaux Valerie J. , Barkhuizen Mark , Brombacher Frank , De Baetselier Patrick , Ryffel Bernhard , Magez Stefan
Published: April 2014

The initial host response toward the extracellular parasite Trypanosoma brucei is characterized by the early release of inflammatory mediators associated with a type 1 immune response. In this study, we show that this inflammatory response is dependent on activation of the innate immune system mediated by the adaptor molecule MyD88. In the present study, MyD88-deficient macrophages are nonresponsive toward both soluble variant-specific surface glycoprotein (VSG), as well as membrane-bound VSG purified from T. brucei. Infection of MyD88-deficient mice with either clonal or nonclonal stocks of T. brucei resulted in elevated levels of parasitemia. This was accompanied by reduced plasma IFN-γ and TNF levels during the initial stage of infection, followed by moderately lower VSG-specific IgG2a Ab titers during the chronic stages of infection. Analysis of several TLR-deficient mice revealed a partial requirement for TLR9 in the production of IFN-γ and VSG-specific IgG2a Ab levels during T. brucei infections. These results implicate the mammalian TLR family and MyD88 signaling in the innate immune recognition of T. brucei.
IL-10 from Regulatory T Cells Determines Vaccine Efficacy in Murine Leishmania major Infection
Authors: Stober Carmel B. , Lange Uta G. , Roberts Mark T. M. , Alcami Antonio , Blackwell Jenefer M.
Published: April 2014

Leishmaniasis affects 12 million people, but there are no vaccines. Immunological correlates of vaccine efficacy are unclear. Polarized Th1 vs Th2 responses in Leishmania major-infected mice suggested that a shift in balance from IL-4 to IFN-γ was the key to vaccine success. Recently, a role for IL-10 and regulatory T cells in parasite persistence was demonstrated, prompting re-evaluation of vaccine-induced immunity. We compared DNA/modified vaccinia virus Ankara heterologous prime-boost with Leishmania homolog of the receptor for activated C kinase (LACK) or tryparedoxin peroxidase (TRYP). Both induced low IL-4 and high IFN-γ prechallenge. Strikingly, high prechallenge CD4 T cell-derived IL-10 predicted vaccine failure using LACK, whereas low IL-10 predicted protection with TRYP. The ratio of IFN-γ:IL-10 was thus a clear prechallenge indicator of vaccine success. Challenge infection caused further polarization to high IL-10/low IFN-γ with LACK and low IL-10/high IFN-γ with TRYP. Ex vivo quantitative RT-PCR and in vitro depletion and suppression experiments demonstrated that Ag-driven CD4+CD25+ T regulatory 1-like cells were the primary source of IL-10 in LACK-vaccinated mice. Anti-IL-10R treatment in vivo demonstrated that IL-10 was functional in determining vaccine failure, rendering LACK protective in the presence of high IFN-γ/low IL-5 responses.
Ligation of Cell Surface-Associated Glucose-Regulated Protein 78 by Receptor-Recognized Forms of α2-Macroglobulin: Activation of p21-Activated Protein Kinase-2-Dependent Signaling in Murine Peritoneal Macrophages
Authors: Misra Uma Kant , Sharma Tushar , Pizzo Salvatore Vincent
Published: April 2014

Previous studies of the plasma proteinase inhibitor α2-macroglobulin (α2M) demonstrated that α2M-proteinase complexes (α2M*) modulate immune responses and promotes macrophage locomotion and chemotaxis. α2M* binds to cell surface-associated glucose-regulated protein 78 (GRP78), which activates downstream signaling events. The role of p21-activated protein kinase-1 and -2 (PAK-1 and -2) in promoting cellular motility is well documented. In the current study, we examined the ability of α2M* to activate PAK-1 and PAK-2. Upon macrophage stimulation with α2M*, PAK-2 is autophosphorylated, resulting in increased kinase activity; however, PAK-1 is negligibly affected. α2M*-stimulated macrophages showed a marked elevation in the levels of Rac·GTP. Receptor tyrosine phosphorylation upon binding of α2M* to GRP78, recruits PAK-2 to the plasma membrane via the adaptor protein NCK. Consistent with this hypothesis, silencing of GRP78 gene expression greatly attenuated the levels of membrane-associated PAK-2 and NCK. PAK-2 activity was markedly decreased by inhibition of tyrosine kinases and PI3K before α2M* stimulation. We further demonstrate that phosphorylation of Lin-11, Isl-1, Mec-3 (LIM) kinase and cofilin is promoted by treating macrophages with α2M*. Thus, α2M* regulates activation of the PAK-2-dependent motility mechanism in these cells.
Heterozygous Arg753Gln Polymorphism of Human TLR-2 Impairs Immune Activation by Borrelia burgdorferi and Protects from Late Stage Lyme Disease
Authors: Schröder Nicolas W. J. , Diterich Isabel , Zinke Antje , Eckert Jana , Draing Christian , Baehr Volker v. , Hassler Dieter , Priem Susanne , Hahn Katrin , Michelsen Kathrin S. , Hartung Thomas , Burmester Gerd R. , Göbel Ulf B. , Hermann Corinna , Schumann Ralf R.
Published: April 2014

Lyme disease (LD) is caused by Borrelia burgdorferi and displays different stages, including localized, early disseminated, and persistent infection, all of which are associated with profound inflammatory reactions in the host. Induction of proinflammatory cytokines by B. burgdorferi is mainly mediated by outer surface proteins interacting with TLR-2/TLR-1 heterodimers. In this study, we show that TNF-α induction by Borrelia lysate was impaired in heterozygous TLR-2 knockout mice, while reactivity to lipoteichoic acid, another TLR-2 ligand signaling via TLR-2/TLR-6 heterodimers, was unaffected. Blood from individuals heterozygous for the TLR-2 polymorphism Arg753Gln was tested for cytokine release upon stimulation with Borrelia lysate, and induction of TNF-α and IFN-γ was significantly lower as compared with individuals not exhibiting this variation. Overexpression of TLR-2 carrying the Arg753Gln polymorphism in HEK 293 cells led to a significantly stronger impairment of activation by TLR-2/TLR-1 ligands as compared with TLR-2/TLR-6 ligands. To study whether heterozygosity for the Arg753Gln variant of TLR-2 influenced susceptibility for LD, we analyzed 155 patients for this polymorphism. The Arg753Gln variant occurs at a significantly lower frequency in LD patients as compared with matched controls (5.8 vs 13.5%, odds ratio 0.393, 95% confidence interval 0.17–0.89, p = 0.033), with an even more pronounced difference when late stage disease was observed (2.3 vs 12.5%, odds ratio 0.163, 95% confidence interval 0.04–0.76, p = 0.018). These data suggest that Arg753Gln may protect from the development of late stage LD due to a reduced signaling via TLR-2/TLR-1.
Immune Regulation of Protease-Activated Receptor-1 Expression in Murine Small Intestine during Nippostrongylus brasiliensis Infection
Authors: Zhao Aiping , Morimoto Motoko , Dawson Harry , Elfrey Justin E. , Madden Kathleen B. , Gause William C. , Min Booki , Finkelman Fred D. , Urban Joseph F. , Shea-Donohue Terez
Published: April 2014

Infection with gastrointestinal nematodes exerts profound effects on both immune and physiological responses of the host. Helminth infection induces a hypercontractility of intestinal smooth muscle that is dependent on the Th2 cytokines, IL-4 and IL-13, and may contribute to worm expulsion. Protease-activated receptors (PARs) are expressed throughout the gut, and activation of PAR-1 was observed in asthma, a Th2-driven pathology. In the current study we investigated the physiologic and immunologic regulation of PAR-1 in the murine small intestine, specifically 1) the effect of PAR-1 agonists on small intestinal smooth muscle contractility, 2) the effects of Nippostrongylus brasiliensis infection on PAR-1 responses, 3) the roles of IL-13 and IL-4 in N. brasiliensis infection-induced alterations in PAR-1 responses, and 4) the STAT6 dependence of these responses. We demonstrate that PAR-1 activation induces contraction of murine intestinal smooth muscle that is enhanced during helminth infection. This hypercontractility is associated with an elevated expression of PAR-1 mRNA and protein. N. brasiliensis-induced changes in PAR-1 function and expression were seen in IL-4-deficient mice, but not in IL-13- or STAT6-deficient mice, indicating the dependence of IL-13 on the STAT6 signaling pathway independent of IL-4.
Identification of High and Low Responders to Lipopolysaccharide in Normal Subjects: An Unbiased Approach to Identify Modulators of Innate Immunity
Authors: Wurfel Mark M. , Park William Y. , Radella Frank , Ruzinski John , Sandstrom Andrew , Strout Jeanna , Bumgarner Roger E. , Martin Thomas R.
Published: April 2014

LPS stimulates a vigorous inflammatory response from circulating leukocytes that varies greatly from individual to individual. The goal of this study was to use an unbiased approach to identify differences in gene expression that may account for the high degree of interindividual variability in inflammatory responses to LPS in the normal human population. We measured LPS-induced cytokine production ex vivo in whole blood from 102 healthy human subjects and identified individuals who consistently showed either very high or very low responses to LPS (denoted lpshigh and lpslow, respectively). Comparison of gene expression profiles between the lpshigh and lpslow individuals revealed 80 genes that were differentially expressed in the presence of LPS and 21 genes that were differentially expressed in the absence of LPS (p < 0.005, ANOVA). Expression of a subset of these genes was confirmed using real-time RT-PCR. Functional relevance for one gene confirmed to be expressed at a higher level in lpshigh, adipophilin, was inferred when reduction in adipophilin mRNA by small interfering RNA in the human monocyte-like cell line THP-1 resulted in a modest but significant reduction in LPS-induced MCP-1 mRNA expression. These data illustrate a novel approach to the identification of factors that determine interindividual variability in innate immune inflammatory responses and identify adipophilin as a novel potential regulator of LPS-induced MCP-1 production in human monocytes.
Matrix Metalloproteinase-8 Deficiency Promotes Granulocytic Allergen-Induced Airway Inflammation
Authors: Gueders Maud M. , Balbin Milagros , Rocks Natacha , Foidart Jean-Michel , Gosset Philippe , Louis Renaud , Shapiro Steven , Lopez-Otin Carlos , Noël Agnes , Cataldo Didier D.
Published: April 2014

Matrix metalloproteinases (MMPs) are involved in inflammatory reaction, including asthma-related airway inflammation. MMP-8, mainly produced by neutrophils, has recently been reported to be increased in the bronchoalveolar lavage fluid (BALF) from asthmatic patients. To evaluate the role of MMP-8 in asthma, we measured MMP-8 expression in lung tissue in an OVA-sensitized mouse model of asthma and addressed the effect of MMP-8 deletion on allergen-induced bronchial inflammation. MMP-8 production was increased in lungs from C57BL/6 mice exposed to allergens. After allergen exposure, MMP-8−/− mice developed an airway inflammation characterized by an increased neutrophilic inflammation in BALF and an increased neutrophilic and eosinophilic infiltration in the airway walls. MMP-8 deficiency was associated with increased levels of IL-4 and anti-OVA IgE and IgG1 in BALF and serum, respectively. Although allergen exposure induced an enhancement of LPS-induced CXC chemokine, KC, and MIP-2 levels in BALF and lung parenchyma, no difference was observed between the two genotypes. Inflammatory cell apoptosis was reduced in the lungs from MMP-8−/− mice. For the first time, our study evidences an important role of MMP-8 in the control of neutrophilic and eosinophilic infiltration during allergen-induced lung inflammation, and demonstrates that the anti-inflammatory effect of MMP-8 is partly due to a regulation of inflammatory cell apoptosis.
Prostaglandin E2 Stimulates Granulocyte Colony-Stimulating Factor Production via the Prostanoid EP2 Receptor in Mouse Peritoneal Neutrophils
Authors: Sugimoto Yukihiko , Fukada Yoko , Mori Daisuke , Tanaka Satoshi , Yamane Hana , Okuno Yasushi , Deai Katsuya , Tsuchiya Soken , Tsujimoto Gozoh , Ichikawa Atsushi
Published: April 2014

G-CSF is a hemopoietic growth factor involved in granulocytic differentiation of progenitor cells. In this study, we investigated the effects of PGE2 on G-CSF production in murine peritoneal neutrophils in vitro and in vivo. PGE2 augmented LPS-primed G-CSF release from peritoneal neutrophils. This augmentation was mimicked by a type E prostanoid receptor (EP)2-selective agonist but not by other EP-specific agonists. Indeed, the effect of PGE2 on G-CSF release was abolished in neutrophils isolated from EP2-deficient mice. PGE2 and an EP2 agonist have the ability to stimulate G-CSF gene expression even in the absence of LPS. In the casein-induced peritonitis model, the appearance of G-CSF in the casein-injected peritoneal cavity associated well with the timing of neutrophil infiltration as well as PGE2 levels in exudates, with a peak value at 6 h postinjection. Inhibition of endogenous PG synthesis by indomethacin resulted in a marked decrease in G-CSF content and neutrophil number in the peritoneal cavity. Moreover, EP2-deficient mice exhibited a strikingly reduced G-CSF content in peritoneal exudates with comparable responses in neutrophil migration and local PGE2 production at 6 h postinjection. These results suggest that the PGE2-EP2 system contributes to the local production of G-CSF during acute inflammation.
Mobilization of Human Lymphoid Progenitors after Treatment with Granulocyte Colony-Stimulating Factor
Authors: Imamura Rie , Miyamoto Toshihiro , Yoshimoto Goichi , Kamezaki Kenjiro , Ishikawa Fumihiko , Henzan Hideho , Kato Koji , Takase Ken , Numata Akihiko , Nagafuji Koji , Okamura Takashi , Sata Michio , Harada Mine , Inaba Shoichi
Published: April 2014

Hemopoietic stem and progenitor cells ordinarily residing within bone marrow are released into the circulation following G-CSF administration. Such mobilization has a great clinical impact on hemopoietic stem cell transplantation. Underlying mechanisms are incompletely understood, but may involve G-CSF-induced modulation of chemokines, adhesion molecules, and proteolytic enzymes. We studied G-CSF-induced mobilization of CD34+CD10+CD19−Lin− and CD34+CD10+CD19+Lin− cells (early B and pro-B cells, respectively). These mobilized lymphoid populations could differentiate only into B/NK cells or B cells equivalent to their marrow counterparts. Mobilized lymphoid progenitors expressed lymphoid- but not myeloid-related genes including the G-CSF receptor gene, and displayed the same pattern of Ig rearrangement status as their bone marrow counterparts. Decreased expression of VLA-4 and CXCR-4 on mobilized lymphoid progenitors as well as multipotent and myeloid progenitors indicated lineage-independent involvement of these molecules in G-CSF-induced mobilization. The results suggest that by acting through multiple trans-acting signals, G-CSF can mobilize not only myeloid-committed populations but a variety of resident marrow cell populations including lymphoid progenitors.
Nuclear Autoantigen Translocation and Autoantibody Opsonization Lead to Increased Dendritic Cell Phagocytosis and Presentation of Nuclear Antigens: A Novel Pathogenic Pathway for Autoimmunity?
Authors: Frisoni Lorenza , Mcphie Lenese , Colonna Lucrezia , Sriram Uma , Monestier Marc , Gallucci Stefania , Caricchio Roberto
Published: April 2014

Autoreactivity in lupus requires the delivery of autoantigens to APCs in a proinflammatory context. It has been proposed that apoptotic cells are a source of lupus autoantigens and targets for autoantibodies. Using a histone H2B-GFP fusion protein as traceable Ag, we show here that lupus autoantibodies, directed against nuclear autoantigens, can opsonize apoptotic cells, enhance their uptake through induction of proinflammatory FcγR-mediated phagocytosis, and augment Ag-specific T cell proliferation by increasing Ag loading. Apoptotic blebs and bodies seemed to be a preferred target of DC phagocytosis, via both “eat-me signals” and FcγR-mediated mechanisms; furthermore, inhibition of nuclear Ag redistribution, by blockade of chromatin fragmentation, could stop binding and opsonization of apoptotic cells by autoantibodies, and inhibited Fcγ-R-mediated enhancement of phagocytosis. Our results suggest that DC uptake of opsonized histones and other nuclear Ags from apoptotic cells is a novel pathway for the presentation of nuclear Ags in a highly inflammatory context. Blockade of chromatin fragmentation in lupus is a potential therapeutic approach, which could theoretically limit DC access to autoantigens delivered in proinflammatory context, while leaving available for tolerization those delivered in a noninflammatory context.
Human Bronchial Epithelium Controls TH2 Responses by TH1-Induced, Nitric Oxide-Mediated STAT5 Dephosphorylation: Implications for the Pathogenesis of Asthma
Authors: Eriksson Urs , Egermann Ulrich , Bihl Michel P. , Gambazzi Franco , Tamm Michael , Holt Patrick G. , Bingisser Roland M.
Published: April 2014

Increased levels of NO in exhaled air in association with increased NO synthetase (NOS)2 expression in bronchial epithelial are hallmark features of asthma. It has been suggested that NO contributes to asthma pathogenesis by selective down-regulation of TH1 responses. We demonstrate, however, that NO can reversibly limit in vitro expansion of both human TH1 and TH2 CD4+ T cells. Mechanistically, NO induces cGMP-mediated reversible STAT5 dephosphorylation and therefore interferes with the IL-2R activation cascade. Human bronchial epithelial cells (HBEC) up-regulate NOS2 after stimulation with IFN-γ secreted by TH1 CD4+ T cells and release NO, which inhibits both TH1 and TH2 cell proliferation. This reversible T cell growth arrest depends on NO because T cell proliferation is completely restored after in vitro blocking of NOS2 on HBEC. HBEC thus drive the effector end of a TH1-controlled feedback loop, which protects airway mucosal tissues at the potential lesional site in asthma from overwhelming CD4+ TH2 (and potentially TH1) responses following allergen exposure. Variations in the efficiency of this feedback loop provides a plausible mechanism to explain why only a subset of atopics sensitized to ubiquitous aeroallergens progress to expression of clinically relevant levels of airways inflammation.
Activation of Thymic Regeneration in Mice and Humans following Androgen Blockade
Authors: Sutherland Jayne S. , Goldberg Gabrielle L. , Hammett Maree V. , Uldrich Adam P. , Berzins Stuart P. , Heng Tracy S. , Blazar Bruce R. , Millar Jeremy L. , Malin Mark A. , Chidgey Ann P. , Boyd Richard L.
Published: April 2014

The thymus undergoes age-related atrophy, coincident with increased circulating sex steroids from puberty. The impact of thymic atrophy is most profound in clinical conditions that cause a severe loss in peripheral T cells with the ability to regenerate adequate numbers of naive CD4+ T cells indirectly correlating with patient age. The present study demonstrates that androgen ablation results in the complete regeneration of the aged male mouse thymus, restoration of peripheral T cell phenotype and function and enhanced thymus regeneration following bone marrow transplantation. Importantly, this technique is also applicable to humans, with analysis of elderly males undergoing sex steroid ablation therapy for prostatic carcinoma, demonstrating an increase in circulating T cell numbers, particularly naive (TREC+) T cells. Collectively these studies represent a fundamentally new approach to treating immunodeficiency states in humans.
Islet-Specific Expression of CXCL10 Causes Spontaneous Islet Infiltration and Accelerates Diabetes Development
Authors: Rhode Antje , Pauza Mary E. , Barral Ana Maria , Rodrigo Evelyn , Oldstone Michael B. A. , von Herrath Matthias G. , Christen Urs
Published: April 2014

During inflammation, chemokines are conductors of lymphocyte trafficking. The chemokine CXCL10 is expressed early after virus infection. In a virus-induced mouse model for type 1 diabetes, CXCL10 blockade abrogated disease by interfering with trafficking of autoaggressive lymphocytes to the pancreas. We have generated transgenic rat insulin promotor (RIP)-CXCL10 mice expressing CXCL10 in the β cells of the islets of Langerhans to evaluate how bystander inflammation influences autoimmunity. RIP-CXCL10 mice have islet infiltrations by mononuclear cells and limited impairment of β cell function, but not spontaneous diabetes. RIP-CXCL10 mice crossed to RIP-nucleoprotein (NP) mice expressing the NP of the lymphocytic choriomeningitis virus in the β cells had massively accelerated type 1 diabetes after lymphocytic choriomeningitis virus infection. Mechanistically, we found a drastic increase in NP-specific, autoaggressive CD8 T cells in the pancreas after infection. In situ staining with H-2Db(NP396) tetramers revealed islet infiltration by NP-specific CD8 T cells in RIP-NP-CXCL10 mice early after infection. Our results indicate that CXCL10 expression accelerates the autoimmune process by enhancing the migration of Ag-specific lymphocytes to their target site.
OX40 and Bcl-xL Promote the Persistence of CD8 T Cells to Recall Tumor-Associated Antigen
Authors: Song Aihua , Tang Xiaohong , Harms Kate Marie , Croft Michael
Published: April 2014

The molecular signals that allow primed CD8 T cells to persist and be effective are particularly important during cancer growth. With response to tumor-expressed Ag following adoptive T cell transfer, we show that CD8 effector cells deficient in OX40, a TNFR family member, could not mediate short-term tumor suppression. OX40 was required at two critical stages. The first was during CD8 priming in vitro, in which APC-transmitted OX40 signals endowed the ability to survive when adoptively transferred in vivo before tumor Ag encounter. The second was during the in vivo recall response of primed CD8 T cells, the stage in which OX40 contributed to the further survival and accumulation of T cells at the tumor site. The lack of OX40 costimulation was associated with reduced levels of Bcl-xL, and retroviral expression of Bcl-xL in tumor-reactive CD8 T cells conferred greatly enhanced tumor protection following adoptive transfer. These data demonstrate that OX40 and Bcl-xL can control survival of primed CD8 T cells and provide new insights into both regulation of CD8 immunity and control of tumors.
The IκB Protein Bcl-3 Negatively Regulates Transcription of the IL-10 Gene in Macrophages
Authors: Riemann Marc , Endres Robert , Liptay Susanne , Pfeffer Klaus , Schmid Roland M.
Published: April 2014

NF-κB/Rel transcription factors, implicated in inflammatory and immune responses against pathogens, are regulated by IκB proteins. The physiological and molecular function of the IκB family member Bcl-3 is understood only poorly. In this study, the role of Bcl-3 in an innate immune response was examined by gene targeting. We demonstrate that Bcl-3−/− mice are highly susceptible to Listeria monocytogenes infection. This correlates with diminished production of IL-12 p70 and IFN-γ in vivo, which is mainly due to elevated synthesis of IL-10. Isolated peritoneal macrophages from Bcl-3−/− mice also produce elevated amounts of IL-10, which inhibit IL-12 p70 synthesis in an autocrine fashion. Thus, these data establish Bcl-3 as an inhibitor of IL-10 expression in macrophages. Furthermore, we show that Bcl-3 is not implicated in IL-10 mRNA stabilization but regulates the initiation of IL-10 transcription. Taken together, our results show that an essential function of Bcl-3 during an innate immune response against bacteria is to inhibit transcription of the IL-10 gene in macrophages.
T Cell Epitope-Containing Peptides of the Major Dog Allergen Can f 1 as Candidates for Allergen Immunotherapy
Authors: Immonen Anu , Farci Sandrine , Taivainen Antti , Partanen Jukka , Pouvelle-Moratille Sandra , Närvänen Ale , Kinnunen Tuure , Saarelainen Soili , Rytkönen-Nissinen Marja , Maillere Bernard , Virtanen Tuomas
Published: April 2014

One prerequisite for developing peptide-based allergen immunotherapy is knowing the T cell epitopes of an allergen. In this study, human T cell reactivity against the major dog allergen Can f 1 was investigated to determine peptides suitable for immunotherapy. Seven T cell epitope regions (A–G) were found in Can f 1 with specific T cell lines and clones. The localization of the epitope regions shows similarities with those of the epitopes found in Bos d 2 and Rat n 1. On average, individuals recognized three epitopes in Can f 1. Our results suggest that seven 16-mer peptides (p15–30, p33–48, p49–64, p73–88, p107–122, p123–138, and p141–156), each from one of the epitope regions, show widespread T cell reactivity in the population studied, and they bind efficiently to seven HLA-DRB1 molecules (DRB1*0101, DRB1*0301, DRB1*0401, DRB1*0701, DRB1*1101, DRB1*1301, and DRB1*1501) predominant in Caucasian populations. Therefore, these peptides are potential candidates for immunotherapy of dog allergy.
Ionic Binding of C3 to the Human Pathogen Moraxella catarrhalis Is a Unique Mechanism for Combating Innate Immunity
Authors: Nordström Therése , Blom Anna M. , Tan Thuan Tong , Forsgren Arne , Riesbeck Kristian
Published: April 2014

Moraxella catarrhalis ubiquitous surface proteins A1 and A2 (UspA1/A2) interfere with the classical pathway of the complement system by binding C4b-binding protein. In this study we demonstrate that M. catarrhalis UspA1 and A2 noncovalently and in a dose-dependent manner bind both the third component of complement (C3) from EDTA-treated serum and methylamine-treated C3. In contrast, related Moraxella subspecies (n = 13) or other human pathogenic bacteria (n = 13) do not bind C3 or methylamine-treated C3. Experiments with recombinant proteins and M. catarrhalis mutants devoid of UspA1/A2 revealed that UspA1/A2 exert their actions by absorbing and neutralizing C3 from serum and restrain complement activation. UspA2 was responsible for most of the effect, and the Moraxella mutant lacking UspA2 was more sensitive to the lytic effect of human serum compared with the wild type. Interestingly, among the large number of bacteria analyzed, only M. catarrhalis has this unique ability to interfere with the innate immune system of complement by binding C3.
Human T Cells Constitutively Express IL-15 That Promotes Ex Vivo T Cell Homeostatic Proliferation through Autocrine/Juxtacrine Loops
Authors: Miranda-Carús María-Eugenia , Benito-Miguel Marta , Llamas Miguel A. , Balsa Alejandro , Martín-Mola Emilio
Published: April 2014

Homeostatic proliferation of T cells in vivo is responsible for the maintainance of the T cell pool, and IL-15 is a pivotal cytokine implicated in this process. Known cell sources providing physiologically active IL-15 are monocytes/macrophages, dendritic cells, and stromal cells. T lymphocyte expression of functionally active IL-15 and its possible role in T cell biology have not been investigated. In this study, we demonstrate that human T cells constitutively express IL-15 that acts through autocrine/juxtacrine loops to promote ex vivo homeostatic T cell proliferation.
Fusion to Listeriolysin O and Delivery by Listeria monocytogenes Enhances the Immunogenicity of HER-2/neu and Reveals Subdominant Epitopes in the FVB/N Mouse
Authors: Singh Reshma , Dominiecki Mary E. , Jaffee Elizabeth M. , Paterson Yvonne
Published: April 2014

Five overlapping fragments of rat HER-2/neu have been expressed in recombinant Listeria monocytogenes. Each fragment of HER-2/neu is secreted as a fusion protein with a truncated, nonhemolytic form of listeriolysin O (LLO). Lm-LLO-EC1, Lm-LLO-EC2, and Lm-LLO-EC3 overlap the extracellular domain of HER-2/neu, whereas Lm-LLO-IC1 and Lm-LLO-IC2 span the intracellular domain. All five strains controlled the growth of established NT-2 tumors, a rat HER-2/neu-expressing tumor line derived from a spontaneously arising mammary tumor in a FVB/N HER-2/neu-transgenic mouse. The antitumor effect of each of these vaccine constructs was abrogated by the in vivo depletion of CD8+ T cells, although only one known epitope has been defined previously and is present in Lm-LLO-EC2. Anti-HER-2/neu CTL responses were generated by each of the rLm vaccine constructs. With the use of a panel of 3T3 cell lines expressing overlapping fragments of HER-2/neu, regions of HER-2/neu with potential CD8+ T cell epitopes have been defined. DNA vaccines expressing either a fragment or full-length HER-2/neu were constructed in LLO-fused and non-LLO-fused forms. CTL analysis of the DNA vaccines revealed a broadening in the regions of HER-2/neu recognizable as targets when the target Ag is fused to LLO. These studies show the efficacy of L. monocytogenes-based HER-2/neu vaccines in a murine model of breast cancer and also that the immunogenicity of self-Ags can be increased by fusion to LLO and delivery by L. monocytogenes revealing subdominant epitopes.
Inhibition of Natural Type I IFN-Producing and Dendritic Cell Development by a Small Molecule Receptor Tyrosine Kinase Inhibitor with Flt3 Affinity
Authors: Tussiwand Roxane , Onai Nobuyuki , Mazzucchelli Luca , Manz Markus G.
Published: April 2014

In vivo steady-state type I natural IFN-producing and dendritic cell (DC) development is largely dependent on Flt3 signaling. Natural IFN-producing and DC progenitors and their respective downstream cell populations express the flt3 receptor, and Flt3 ligand (Flt3L)−/− mice have reduced while Flt3L-injected mice develop markedly increased numbers of both cell types. In the present study, we show that SU11657, a small multitargeted receptor tyrosine kinase inhibitor with Flt3 affinity, suppressed in vitro natural IFN-producing and DC development in Flt3L-supplemented mouse whole bone marrow cell cultures in a dose-dependant manner, while DC development in GM-CSF-supplemented cultures was not affected. In vivo SU11657 application led to a significant decrease of both natural IFN-producing and DCs, comparable to the reduction observed in Flt3L−/− mice. Conversely, Flt3L plasma levels increased massively in inhibitor-treated animals, likely via a regulatory feedback loop, without being able to compensate for pharmacological Flt3 inhibition. No obvious toxicity was observed, and hemopoietic progenitor cell and stem cell function remained intact as assessed by myeloid colony-forming unit activity and in vivo bone marrow repopulation assays. Furthermore, upon treatment discontinuation, IFN-producing and DCs recovered to normal levels, proving that treatment effects were transient. Given the importance of IFN-producing and DCs in regulation of immune responses, these findings might lead to new pharmacological strategies in prevention and treatment of autoimmune diseases and complications of organ or blood cell transplantation.