bluuebunny/crossref_metadata_2025_split huggingface dataset:
Absence of TRIF Signaling in Lipopolysaccharide-Stimulated Murine Mast Cells
Authors: Keck Simone , Müller Ines , Fejer György , Savic Iva , Tchaptchet Sandrine , Nielsen Peter J. , Galanos Chris , Huber Michael , Freudenberg Marina A. 
Published: March 2011

Abstract
In macrophages, two signaling pathways, dependent on MyD88 or TIR domain-containing adaptor-inducing IFN-β (TRIF) signaling, emanate from the LPS receptor TLR4/MD-2. In this study, we show that in murine bone marrow-derived mast cells (BMMCs), only the MyD88-dependent pathway is activated by LPS. The TRIF signaling branch leading both to NF-κB activation and enhanced proinflammatory cytokine production, as well as to IRF3 activation and subsequent IFN-β production, is absent in LPS-stimulated BMMCs. IRF3 activation is also absent in peritoneal mast cells from LPS-injected mice. We observed strongly diminished TRAM expression in BMMCs, but overexpression of TRAM only moderately enhanced IL-6 and did not boost IFN-β responses to LPS in these cells. A combination of very low levels of TRAM and TLR4/MD-2 with the known absence of membrane-bound CD14 are expected to contribute to the defective TRIF signaling in mast cells. We also show that, unlike in macrophages, in BMMCs the TRIF-dependent and -independent IFN-αβ responses to other recognized IFN inducers (dsRNA, adenovirus, and B-DNA) are absent. These results show how the response to the same microbial ligand using the same receptor can be regulated in different cell types of the innate immune system.
Testosterone Replacement Effectively Inhibits the Development of Experimental Autoimmune Orchitis in Rats: Evidence for a Direct Role of Testosterone on Regulatory T Cell Expansion
Authors: Fijak Monika , Schneider Eva , Klug Jörg , Bhushan Sudhanshu , Hackstein Holger , Schuler Gerhard , Wygrecka Malgorzata , Gromoll Jörg , Meinhardt Andreas 
Published: March 2011

AbstractDespite the immune-privileged status of the male genital tract, infection and inflammation of the male genital tract are important etiological factors in male infertility. A common observation in clinical and experimental orchitis as well as in systemic infection and inflammation are decreased levels of testosterone. Emerging data point to an immunosuppressive role of testosterone. In our study, we substituted testosterone levels in experimental autoimmune orchitis (EAO) in rat by s.c. testosterone implants. EAO development was reduced to 17% when animals were treated with low-dose testosterone implants (3 cm long, EAO+T3) and to 33% when rats were supplied with high-dose testosterone implants (24 cm, EAO+T24) compared with 80% of animals developing disease in the EAO control group. In the testis, testosterone replacement in EAO animals prevented the accumulation of macrophages and significantly reduced the number of CD4+ T cells with a strong concomitant increase in the number of regulatory T cells (CD4+CD25+Foxp3+) compared with EAO control. In vitro testosterone treatment of naive T cells led to an expansion of the regulatory T cell subset with suppressive activity and ameliorated MCP-1–stimulated chemotaxis of T lymphocytes in a Transwell assay. Moreover, expression of proinflammatory mediators such as MCP-1, TNF-α, and IL-6 in the testis and secretion of Th1 cytokines such as IFN-γ and IL-2 by mononuclear cells isolated from testicular draining lymph nodes were decreased in the EAO+T3 and EAO+T24 groups. Thus, our study shows an immunomodulatory and protective effect of testosterone substitution in the pathogenesis of EAO and suggests androgens as a new factor in the differentiation of regulatory T cells.
The Therapeutic Potential of the Humoral Pattern Recognition Molecule PTX3 in Chronic Lung Infection Caused by Pseudomonas aeruginosa
Authors: Moalli Federica , Paroni Moira , Véliz Rodriguez Tania , Riva Federica , Polentarutti Nadia , Bottazzi Barbara , Valentino Sonia , Mantero Stefano , Nebuloni Manuela , Mantovani Alberto , Bragonzi Alessandra , Garlanda Cecilia 
Published: March 2011

Abstract
Chronic lung infections by Pseudomonas aeruginosa strains are a major cause of morbidity and mortality in cystic fibrosis (CF) patients. Although there is no clear evidence for a primary defect in the immune system of CF patients, the host is generally unable to clear P. aeruginosa from the airways. PTX3 is a soluble pattern recognition receptor that plays nonredundant roles in the innate immune response to fungi, bacteria, and viruses. In particular, PTX3 deficiency is associated with increased susceptibility to P. aeruginosa lung infection. To address the potential therapeutic effect of PTX3 in P. aeruginosa lung infection, we established persistent and progressive infections in mice with the RP73 clinical strain RP73 isolated from a CF patient and treated them with recombinant human PTX3. The results indicated that PTX3 has a potential therapeutic effect in P. aeruginosa chronic lung infection by reducing lung colonization, proinflammatory cytokine levels (CXCL1, CXCL2, CCL2, and IL-1β), and leukocyte recruitment in the airways. In models of acute infections and in in vitro assays, the prophagocytic effect of PTX3 was maintained in C1q-deficient mice and was lost in C3- and Fc common γ-chain–deficient mice, suggesting that facilitated recognition and phagocytosis of pathogens through the interplay between complement and FcγRs are involved in the therapeutic effect mediated by PTX3. These data suggested that PTX3 is a potential therapeutic tool in chronic P. aeruginosa lung infections, such as those seen in CF patients.
MHC Class II Engagement by Its Ligand LAG-3 (CD223) Contributes to Melanoma Resistance to Apoptosis
Authors: Hemon Patrice , Jean-Louis Francette , Ramgolam Kiran , Brignone Chrystelle , Viguier Manuelle , Bachelez Hervé , Triebel Frédéric , Charron Dominique , Aoudjit Fawzi , Al-Daccak Reem , Michel Laurence 
Published: March 2011

Abstract
Melanoma is the most aggressive skin cancer in humans that often expresses MHC class II (MHC II) molecules, which could make these tumors eliminable by the immune system. However, this MHC II expression has been associated with poor prognosis, and there is a lack of immune-mediated eradication. The lymphocyte activation gene-3 (LAG-3) is a natural ligand for MHC II that is substantially expressed on melanoma-infiltrating T cells including those endowed with potent immune-suppressive activity. Based on our previous data showing the signaling capacity of MHC II in melanoma cells, we hypothesized that LAG-3 could contribute to melanoma survival through its MHC II signaling capacity in melanoma cells. In this study, we demonstrate that both soluble LAG-3 and LAG-3–transfected cells can protect MHC II-positive melanoma cells, but not MHC II-negative cells, from FAS-mediated and drug-induced apoptosis. Interaction of LAG-3 with MHC II expressed on melanoma cells upregulates both MAPK/Erk and PI3K/Akt pathways, albeit with different kinetics. Inhibition studies using specific inhibitors of both pathways provided evidence of their involvement in the LAG-3–induced protection from apoptosis. Altogether, our data suggest that the LAG-3–MHC II interaction could be viewed as a bidirectional immune escape pathway in melanoma, with direct consequences shared by both melanoma and immune cells. In the future, compounds that efficiently hinder LAG-3–MHC II interaction might be used as an adjuvant to current therapy for MHC II-positive melanoma.
Host Defense Peptide LL-37 Selectively Reduces Proinflammatory Macrophage Responses
Authors: Brown Kelly L. , Poon Grace F. T. , Birkenhead Darlene , Pena Olga M. , Falsafi Reza , Dahlgren Claes , Karlsson Anna , Bylund Johan , Hancock Robert E. W. , Johnson Pauline 
Published: March 2011

Abstract
The human cathelicidin peptide, LL-37, is a host defense peptide with a wide range of immunomodulatory activities and modest direct antimicrobial properties. LL-37 can exert both pro- and anti-inflammatory effects and can modulate the proinflammatory responses of human peripheral blood monocytes and epithelial cells. In this study, we evaluated the effect of LL-37 on mouse bone marrow-derived macrophages (BMDM) and tissue macrophages in vitro and in vivo. LL-37 dramatically reduced TNF-α and NO levels produced by LPS and IFN-γ–polarized M1-BMDM and slightly reduced reactive oxygen species production by these cells. LL-37 did not affect the ability of IL-4–polarized M2-BMDM to upregulate arginase activity, although it did inhibit LPS-induced TNF-α secretion in these cells. LL-37 did not compromise the ability of M1-polarized BMDM to phagocytose and kill bacteria and did not affect the uptake of apoptotic neutrophils by M2-polarized BMDM. However, LL-37-treated M1-BMDM were more efficient at suppressing tumor growth in vitro. LL-37 significantly reduced LPS-induced TNF-α secretion in ex vivo alveolar macrophages, whereas its effect on peritoneal macrophages was much less dramatic. Effective inhibition of LPS-induced TNF-α secretion by alveolar macrophages also occurred in vivo when LL-37 was administered by intratracheal injection. This demonstrates a selective ability of LL-37 to decrease M1-BMDM, M2-BMDM, and tissue macrophage production of the proinflammatory cytokine TNF-α in response to LPS while leaving other crucial anti-inflammatory M1 and M2 macrophage functions unaltered.
Circulating Human Antibody-Secreting Cells during Vaccinations and Respiratory Viral Infections Are Characterized by High Specificity and Lack of Bystander Effect
Authors: Lee F. Eun-Hyung , Halliley Jessica L. , Walsh Edward E. , Moscatiello Andrew P. , Kmush Brittany L. , Falsey Ann R. , Randall Troy D. , Kaminiski Denise A. , Miller Richard K. , Sanz Iñaki 
Published: March 2011

Abstract
Surges of serum Abs after immunization and infection are highly specific for the offending Ag, and recent studies demonstrate that vaccines induce transient increases in circulating Ab-secreting cells (ASCs). These ASCs are highly enriched but not universally specific for the immunizing Ag, suggesting that a fraction of these ASCs could arise from polyclonal bystander stimulation of preexisting memory cells to unrelated Ags. This model is proposed to explain maintenance of long-lived serological memory in the absence of Ag exposure. To test this model, we measure the ability of respiratory syncytial virus and influenza virus infection or immunizations to influenza virus, tetanus toxoid, hepatitis B Ag, and human papillomavirus to stimulate bystander memory cells specific for other major environmental Ags that represent a large fraction of the preexisting memory B compartment. Bystander or nonspecific ASC responses to respiratory syncytial virus and tetanus could not be detected above the background levels in healthy adults, despite the presence of circulating memory B cells specific for the corresponding Ags. Nonspecific ASC responses in the healthy subjects and cord blood samples were similar. In contrast, both vaccination and infection induce massive expansion of circulating Ag-specific ASCs without significant increases in the frequencies of ASCs against unrelated Ags. Hence, nonspecific stimulation of memory B cells is unlikely to contribute to the mechanisms of long-term serological memory against major human pathogens. Additionally, high specificity of circulating ASCs after antigenic challenge highlights the diagnostic value of interrogating ASCs as an ideal single-time-point diagnostic immune surrogate for serology during acute infection.
A Novel Leukocyte Adhesion Deficiency III Variant: Kindlin-3 Deficiency Results in Integrin- and Nonintegrin-Related Defects in Different Steps of Leukocyte Adhesion
Authors: Robert Philippe , Canault Matthias , Farnarier Catherine , Nurden Alan , Grosdidier Charlotte , Barlogis Vincent , Bongrand Pierre , Pierres Anne , Chambost Hervé , Alessi Marie-Christine 
Published: March 2011

Abstract
Leukocyte adhesion deficiency type III is a recently described condition involving a Glanzmann-type bleeding syndrome and leukocyte adhesion deficiency. This was ascribed to a defect of the FERMT3 gene resulting in abnormal expression of kindlin-3, a protein expressed in hematopoietic cells with a major role in the regulation of integrin activation. In this article, we describe a patient with a new mutation of FERMT3 and lack of kindlin-3 expression in platelets and leukocytes. We assayed quantitatively the first steps of kindlin-3–defective leukocyte adhesion, namely, initial bond formation, bond strengthening, and early spreading. Initial bond formation was readily stimulated with neutrophils stimulated by fMLF, and neutrophils and lymphocytes stimulated by a phorbol ester or Mn2+. In contrast, attachment strengthening was defective in the patient’s lymphocytes treated with PMA or Mn2+, or fMLF-stimulated neutrophils. However, attachment strengthening was normal in patient’s neutrophils treated with phorbol ester or Mn2+. In addition, the patient’s T lymphocytes displayed defective integrin-mediated spreading and a moderate but significant decrease of spreading on anti-CD3–coated surfaces. Patient’s neutrophils displayed a drastic alteration of integrin-mediated spreading after fMLF or PMA stimulation, whereas signaling-independent Mn2+ allowed significant spreading. In conclusion, the consequences of kindlin-3 deficiency on β2 integrin function depend on both cell type and the stimulus used for integrin activation. Our results suggest looking for a possible kindlin-3 involvement in membrane dynamical event independent of integrin-mediated adhesion.
IL-21 Promotes Skin Recruitment of CD4+ Cells and Drives IFN-γ–Dependent Epidermal Hyperplasia
Authors: Sarra Massimiliano , Caruso Roberta , Cupi Maria Laura , Monteleone Ivan , Stolfi Carmine , Campione Elena , Diluvio Laura , Mazzotta Annamaria , Botti Elisabetta , Chimenti Sergio , Costanzo Antonio , MacDonald Thomas T. , Pallone Francesco , Monteleone Giovanni 
Published: March 2011

Abstract
Psoriasis is a chronic inflammatory disorder of the skin characterized by epidermal hyperplasia and infiltration of leukocytes into the dermis and epidermis. T cell-derived cytokines, such as IFN-γ and IL-17A, play a major role in the psoriasis-associated epidermal hyperplasia, even though factors/mechanisms that regulate the production of these cytokines are not fully understood. We have recently shown that IL-21 is synthesized in excess in psoriatic skin lesions and causes epidermal hyperplasia when injected intradermally in mice. Moreover, in the human psoriasis SCID mouse model, neutralization of IL-21 reduces both skin thickening and expression of inflammatory molecules, thus supporting the pathogenic role of IL-21 in psoriasis. However, the basic mechanism by which IL-21 promotes skin pathology remains unknown. In this study, we show that CD4+ cells accumulate early in the dermis of IL-21–treated mice and mediate the development of epidermal hyperplasia. Indeed, IL-21 fails to induce skin damage in RAG1-deficient mice and CD4+ cell-depleted wild-type mice. The majority of CD4+ cells infiltrating the dermis of IL-21–treated mice express IFN-γ and, to a lesser extent, IL-17A. Studies in cytokine knockout mice show that IFN-γ, but not IL-17A, is necessary for IL-21–induced epidermal hyperplasia. Finally, we demonstrate that IFN-γ–producing CD4+ cells infiltrating the human psoriatic plaque express IL-21R, and abrogation of IL-21 signals reduces IFN-γ expression in cultures of psoriatic CD4+ cells. Data indicate that IL-21 induces an IFN-γ–dependent pathogenic response in vivo, thus contributing to elucidate a mechanism by which IL-21 sustains skin-damaging inflammation.
Chronic Exposure to a TLR Ligand Injures Hematopoietic Stem Cells
Authors: Esplin Brandt L. , Shimazu Tomoyuki , Welner Robert S. , Garrett Karla P. , Nie Lei , Zhang Qingzhao , Humphrey Mary Beth , Yang Qi , Borghesi Lisa A. , Kincade Paul W. 
Published: March 2011

Abstract
Hematopoietic stem cells (HSC) can be harmed by disease, chemotherapy, radiation, and normal aging. We show in this study that damage also occurs in mice repeatedly treated with very low doses of LPS. Overall health of the animals was good, and there were relatively minor changes in marrow hematopoietic progenitors. However, HSC were unable to maintain quiescence, and transplantation revealed them to be myeloid skewed. Moreover, HSC from treated mice were not sustained in serial transplants and produced lymphoid progenitors with low levels of the E47 transcription factor. This phenomenon was previously seen in normal aging. Screening identified mAbs that resolve HSC subsets, and relative proportions of these HSC changed with age and/or chronic LPS treatment. For example, minor CD150HiCD48− populations lacking CD86 or CD18 expanded. Simultaneous loss of CD150Lo/−CD48− HSC and gain of the normally rare subsets, in parallel with diminished transplantation potential, would be consistent with age- or TLR-related injury. In contrast, HSC in old mice differed from those in LPS-treated animals with respect to VCAM-1 or CD41 expression and lacked proliferation abnormalities. HSC can be exposed to endogenous and pathogen-derived TLR ligands during persistent low-grade infections. This stimulation might contribute in part to HSC senescence and ultimately compromise immunity.
Lymphotoxin Signal Promotes Thymic Organogenesis by Eliciting RANK Expression in the Embryonic Thymic Stroma
Authors: Mouri Yasuhiro , Yano Masashi , Shinzawa Miho , Shimo Yusuke , Hirota Fumiko , Nishikawa Yumiko , Nii Takuro , Kiyonari Hiroshi , Abe Takaya , Uehara Hisanori , Izumi Keisuke , Tamada Koji , Chen Lieping , Penninger Josef M. , Inoue Jun-ichiro , Akiyama Taishin , Matsumoto Mitsuru 
Published: March 2011

Abstract
It has recently become clear that signals mediated by members of the TNFR superfamily, including lymphotoxin-β receptor (LTβR), receptor activator for NF-κB (RANK), and CD40, play essential roles in organizing the integrity of medullary thymic epithelial cells (mTECs) required for the establishment of self-tolerance. However, details of the mechanism responsible for the unique and cooperative action of individual and multiple TNFR superfamily members during mTEC differentiation still remain enigmatic. In this study, we show that the LTβR signal upregulates expression of RANK in the thymic stroma, thereby promoting accessibility to the RANK ligand necessary for mTEC differentiation. Cooperation between the LTβR and RANK signals for optimal mTEC differentiation was underscored by the exaggerated defect of thymic organogenesis observed in mice doubly deficient for these signals. In contrast, we observed little cooperation between the LTβR and CD40 signals. Thus, the LTβR signal exhibits a novel and unique function in promoting RANK activity for mTEC organization, indicating a link between thymic organogenesis mediated by multiple cytokine signals and the control of autoimmunity.
CXCR3 Deficiency Exacerbates Liver Disease and Abrogates Tolerance in a Mouse Model of Immune-Mediated Hepatitis
Authors: Erhardt Annette , Wegscheid Claudia , Claass Benjamin , Carambia Antonella , Herkel Johannes , Mittrücker Hans-Willi , Panzer Ulf , Tiegs Gisa 
Published: March 2011

Abstract
The chemokine receptor CXCR3 is preferentially expressed by Th1 cells and critically involved in their recruitment to inflamed tissue. In a mouse model of immune-mediated liver injury inducible by Con A, we investigated the role of CXCR3 in acute IFN-γ–mediated hepatitis as well as in tolerance induction, which has been shown to depend on IL-10–producing CD4+CD25+Foxp3+ regulatory T cells (Tregs). Induction of Con A hepatitis resulted in increased intrahepatic expression of the CXCR3 ligands CXCL9, CXCL10, and CXCL11. CXCR3−/− mice developed a more severe liver injury with higher plasma transaminase activities and a more pronounced Th1/Th17 response compared with wild-type (wt) animals upon Con A injection. Moreover, CXCR3−/− mice did not establish tolerance upon Con A restimulation, although Tregs from CXCR3−/− mice were still suppressive in an in vitro suppression assay. Instead, Tregs failed to accumulate in livers of CXCR3−/− mice upon Con A restimulation in contrast to those from wt animals. Con A-tolerant wt mice harbored significantly increased numbers of intrahepatic CXCR3+T-bet+ Tregs that produced IL-10 compared with nontolerant animals. IFN-γ deficiency or anti–IFN-γ Ab treatment demonstrated that conversion to CXCR3+T-bet+ Tregs depended on a Th1 response. Accordingly, in an immunotherapeutic approach, CD4+CD25+Foxp3+ Tregs from Con A-pretreated CXCR3-deficient mice failed to protect against Con A-induced hepatitis, whereas Tregs from Con A-tolerant wt mice allowed CXCR3-deficient mice to recover from Con A hepatitis. In summary, CXCR3+T-bet+IL-10+ Tregs are generated in the liver in dependence of IFN-γ, then disseminated into the organism and specifically migrate into the liver, where they limit immune-mediated liver damage.
A Multifunctional Element in the Mouse Igκ Locus That Specifies Repertoire and Ig Loci Subnuclear Location
Authors: Xiang Yougui , Zhou Xiaorong , Hewitt Susannah L. , Skok Jane A. , Garrard William T. 
Published: March 2011

Abstract
Nonbiased V gene usage for V(D)J joining is essential for providing an optimal immune system, but no cis-acting sequence with this function has been uncovered. We previously identified a recombination silencer and heterochromatin targeting element in the Vκ-Jκ intervening sequence of germline Igκ transgenes, which we termed Sis. We now have generated Sis knockout mice in the endogenous locus. Intriguingly, Sis−/− mice exhibit a skewed Igκ repertoire with markedly decreased distal and enhanced proximal Vκ gene usage for primary rearrangement, which is associated with reduced occupancy of Ikaros and CCCTC-binding factor in the Vκ-Jκ intervening sequence in pre-B cells, proteins believed to be responsible for dampening the recombination of nearby Vκ genes and altering higher-order chromatin looping. Furthermore, monoallelic heterochromatin localization is significantly reduced in Sis−/− mice for Igκ in cis and IgH loci in trans in pre-B cells. Because Sis−/− mice still allelically excluded Igκ and IgH loci and still exhibited IgL isotype exclusion, we concluded that stable localization at pericentromeric heterochromatin is neither necessary nor sufficient for the establishment or maintenance of allelic exclusion. Hence, Sis is a novel multifunctional element that specifies repertoire and heterochromatin localization to Ig genes.