bluuebunny/crossref_metadata_2025 huggingface dataset:
A Causative Relationship Exists Between Eosinophils and the Development of Allergic Pulmonary Pathologies in the Mouse
Authors: Shen HuaHao H. , Ochkur Sergei I. , McGarry Michael P. , Crosby Jeffrey R. , Hines Edie M. , Borchers Michael T. , Wang Huiying , Biechelle Travis L. , O’Neill Katie R. , Ansay Tracy L. , Colbert Dana C. , Cormier Stephania A. , Justice J. Paul , Lee Nancy. A. , Lee James J.
Published: April 2014

Asthma and mouse models of allergic respiratory inflammation are invariably associated with a pulmonary eosinophilia; however, this association has remained correlative. In this report, a causative relationship between eosinophils and allergen-provoked pathologies was established using eosinophil adoptive transfer. Eosinophils were transferred directly into the lungs of either naive or OVA-treated IL-5−/− mice. This strategy resulted in a pulmonary eosinophilia equivalent to that observed in OVA-treated wild-type animals. A concomitant consequence of this eosinophil transfer was an increase in Th2 bronchoalveolar lavage cytokine levels and the restoration of intracellular epithelial mucus in OVA-treated IL-5−/− mice equivalent to OVA-treated wild-type levels. Moreover, the transfer also resulted in the development of airway hyperresponsiveness. These pulmonary changes did not occur when eosinophils were transferred into naive IL-5−/− mice, eliminating nonspecific consequences of the eosinophil transfer as a possible explanation. Significantly, administration of OVA-treated IL-5−/− mice with GK1.5 (anti-CD4) Abs abolished the increases in mucus accumulation and airway hyperresponsiveness following adoptive transfer of eosinophils. Thus, CD4+ T cell-mediated inflammatory signals as well as signals derived from eosinophils are each necessary, yet alone insufficient, for the development of allergic pulmonary pathology. These data support an expanded view of T cell and eosinophil activities and suggest that eosinophil effector functions impinge directly on lung function.
IL-4 Down-Regulates Anaphylatoxin Receptors in Monocytes and Dendritic Cells and Impairs Anaphylatoxin-Induced Migration In Vivo
Authors: Soruri Afsaneh , Kiafard Ziba , Dettmer Claudia , Riggert Joachim , Köhl Jörg , Zwirner Jörg
Published: April 2014

Anaphylatoxins mobilize leukocytes to the sites of inflammation. In the present study we investigated the impact of GM-CSF, IL-4, and IFN-γ on anaphylatoxin receptor expression in monocytes and dendritic cells (DC). IL-4 was identified as the strongest down-regulator of the receptors for C5a and C3a in monocytes and monocyte-derived DC (MoDC). To study the impact of IL-4 on anaphylatoxin-induced chemotaxis, an in vivo migration model was established. For this purpose, human monocytes and MoDC were injected i.v. into SCID mice that at the same time received anaphylatoxins into the peritoneal cavity. A peritoneal influx of human monocytes could be demonstrated by 4 h after injections of C5a and C3a. In line with receptor down-regulation, IL-4 treatment inhibited in vivo mobilization of human monocytes and MoDC in response to C5a and C3a. In addition to its effects on human cells, IL-4 reduced C5a receptors in murine bone marrow-derived DC and impaired recruitment of labeled bone marrow-derived DC in syngeneic BALB/c mice to i.p. injected C5a. Overall, these data suggest that inhibition of a rapid anaphylatoxin-induced mobilization of monocytes and DC to inflamed tissues represents an important anti-inflammatory activity of the Th2 cytokine IL-4.
Redundancy of a Functional Melanocortin 1 Receptor in the Anti-inflammatory Actions of Melanocortin Peptides: Studies in the Recessive Yellow (e/e) Mouse Suggest an Important Role for Melanocortin 3 Receptor
Authors: Getting Stephen J. , Christian Helen C. , Lam Connie W. , Gavins Felicity N. E. , Flower Roderick J. , Schiöth Helgi B. , Perretti Mauro
Published: April 2014

The issue of which melanocortin receptor (MC-R) is responsible for the anti-inflammatory effects of melanocortin peptides is still a matter of debate. Here we have addressed this aspect using a dual pharmacological and genetic approach, taking advantage of the recent characterization of more selective agonists/antagonists at MC1 and MC3-R as well as of the existence of a naturally defective MC1-R mouse strain, the recessive yellow (e/e) mouse. RT-PCR and ultrastructural analyses showed the presence of MC3-R mRNA and protein in peritoneal macrophages (Mφ) collected from recessive yellow (e/e) mice and wild-type mice. This receptor was functional as Mφ incubation (30 min) with melanocortin peptides led to accumulation of cAMP, an effect abrogated by the MC3/4-R antagonist SHU9119, but not by the selective MC4-R antagonist HS024. In vitro Mφ activation, determined as release of the CXC chemokine KC and IL-1β, was inhibited by the more selective MC3-R agonist γ2-melanocyte stimulating hormone but not by the selective MC1-R agonist MS05. Systemic treatment of mice with a panel of melanocortin peptides inhibited IL-1β release and PMN accumulation elicited by urate crystals in the murine peritoneal cavity. MS05 failed to inhibit any of the inflammatory parameters either in wild-type or recessive yellow (e/e) mice. SHU9119 prevented the inhibitory actions of γ2-melanocyte stimulating hormone both in vitro and in vivo while HS024 was inactive in vivo. In conclusion, agonism at MC3-R expressed on peritoneal Mφ leads to inhibition of experimental nonimmune peritonitis in both wild-type and recessive yellow (e/e) mice.
CTLA-4 Blockade Enhances the Therapeutic Effect of an Attenuated Poxvirus Vaccine Targeting p53 in an Established Murine Tumor Model
Authors: Espenschied Jonathan , Lamont Jeffrey , Longmate Jeff , Pendas Solange , Wang Zhongde , Diamond Don J. , Ellenhorn Joshua D. I.
Published: April 2014

p53 is overexpressed by half of all cancers, and is an attractive target for a vaccine approach to immunotherapy. p53 overexpression is frequently the result of point mutations, which leaves the majority of the protein in its wild-type form. Therefore, the majority of p53 sequence is wild type, making it a self-protein for which tolerance plays a role in limiting immune responses. To overcome tolerance to p53, we have expressed wild-type murine p53 in the nonpathogenic attenuated poxvirus, modified vaccinia virus Ankara (recombinant modified vaccinia virus Ankara expressing wild-type murine p53 (rMVAp53)). Mice immunized with rMVAp53 vaccine developed vigorous p53-specific CTL responses. rMVAp53 vaccine was evaluated for its ability to inhibit the outgrowth of the syngeneic murine sarcoma Meth A, which overexpresses mutant p53. Mice were inoculated with a lethal dose (5 × 105 cells injected s.c.) of Meth A tumor cells and vaccinated by i.p. injection 3 days later with 5 × 107 PFU of rMVAp53. The majority of mice remained tumor free and resistant to rechallenge with Meth A tumor cells. We wished to determine whether rMVAp53 immunization could effect the rejection of an established, palpable Meth A tumor. In subsequent experiments, mice were injected with 106 Meth A tumor cells, and treated 6 days later with anti-CTLA-4 Ab (9H10) and rMVAp53. The majority of treated mice had complete tumor regression along with lasting tumor immunity. In vivo Ab depletion confirmed that the antitumor effect was primarily CD8 and to a lesser extent CD4 dependent. These experiments demonstrate the potential of a novel cell-free vaccine targeting p53 in malignancy.
Accumulation of B Lymphocytes with a Naive, Resting Phenotype in a Subset of Hepatitis C Patients
Authors: Ni Jianhua , Hembrador Edgardo , Di Bisceglie Adrian M. , Jacobson Ira M. , Talal Andrew H. , Butera David , Rice Charles M. , Chambers Thomas J. , Dustin Lynn B.
Published: April 2014

Chronic infection with hepatitis C virus (HCV) is associated with disturbances of B lymphocyte activation and function: autoantibody production, mixed cryoglobulinemia, and B cell lymphomas. It has been proposed that these abnormalities reflect chronic antigenic stimulation or aberrant signaling through the B cell coreceptor, the latter mediated by binding of the HCV E2 glycoprotein to CD81. To test this hypothesis, we measured expression of activation and differentiation markers on peripheral blood B cells from patients with chronic HCV infection. Thirty-six HCV patients with and without mixed cryoglobulinemia were compared with 18 healthy control volunteers and 17 sustained virologic responders who had cleared HCV infection. Ten of the 36 HCV patient samples showed increased B cell frequencies; B cell frequency was higher in patients with more severe hepatic fibrosis. However, these samples lacked evidence of Ag-driven activation or proliferation. The expanded cells were low in the activation markers CD25, CD69, CD71, CD80, and CD86. Proliferation of circulating B cells was unchanged in HCV patients. These cells did not express the differentiation marker CD27, suggesting that they were not enriched in memory B cells. Furthermore, the expanded B cells expressed both IgD and IgM, suggesting that they were antigenically naive. Together, these results indicate that B cell expansion in the peripheral blood of HCV patients is not associated with Ag-mediated activation and differentiation. Instead, factors other than antigenic stimulation may promote the accumulation of peripheral blood B cells with a naive phenotype in a subset of HCV patients.
Cutting Edge: Cure of Colitis by CD4+CD25+ Regulatory T Cells
Authors: Mottet Christian , Uhlig Holm H. , Powrie Fiona
Published: April 2014

CD4+CD25+ regulatory T cells have been shown to prevent T cell-mediated immune pathology; however, their ability to ameliorate established inflammation has not been tested. Using the CD4+CD45RBhigh T cell transfer model of inflammatory bowel disease, we show that CD4+CD25+ but not CD4+CD25−CD45RBlow T cells are able to cure intestinal inflammation. Transfer of CD4+CD25+ T cells into mice with colitis led to resolution of the lamina propria infiltrate in the intestine and reappearance of normal intestinal architecture. CD4+CD25+ T cells were found to proliferate in the mesenteric lymph nodes and inflamed colon. They were located between clusters of CD11c+ cells and pathogenic T cells and found to be in contact with both cell types. These studies suggest that manipulation of CD4+CD25+ T cells may be beneficial in the treatment of chronic inflammatory diseases.
Strategic Compartmentalization of Toll-Like Receptor 4 in the Mouse Gut
Authors: Ortega-Cava Cesar F. , Ishihara Shunji , Rumi Mohammad A. K. , Kawashima Kousaku , Ishimura Norihisa , Kazumori Hideaki , Udagawa Jun , Kadowaki Yasunori , Kinoshita Yoshikazu
Published: April 2014

Pattern recognition receptors (PRRs), which include the Toll-like receptors (TLRs), are involved in the innate immune response to infection. TLR4 is a model for the TLR family and is the main LPS receptor. We wanted to determine the expression of TLR4 and compare it with that of TLR2 and CD14 along the gastrointestinal mucosa of normal and colitic BALB/c mice. Colitis was induced with 2.5% dextran sodium sulfate (DSS). Mucosa from seven segments of the digestive tract (stomach, small intestine in three parts, and colon in three parts) was isolated by two different methods. Mucosal TLR4, CD14, TLR2, MyD88, and IL-1β mRNA were semiquantified by Northern blotting. TLR4 protein was determined by Western blotting. TLR4/MD-2 complex and CD14 were evaluated by immunohistochemistry. PRR genes were constitutively expressed and were especially stronger in colon. TLR4 and CD14 mRNA were increased in the distal colon, but TLR2 mRNA was expressed more strongly in the proximal colon, and MyD88 had a uniform expression throughout the gut. Accordingly, TLR4 and CD14 protein levels were higher in the distal colon. TLR4/MD-2 and CD14 were localized at crypt bottom epithelial cells. TLR4/MD2, but not CD14, was found in mucosal mononuclear cells. Finally, DSS-induced inflammation was localized in the distal colon. All genes studied were up-regulated during DSS-induced inflammation, but the normal colon-stressed gut distribution was preserved. Our findings demonstrate that TLR4, CD14, and TLR2 are expressed in a compartmentalized manner in the mouse gut and provide novel information about the in vivo localization of PRRs.
A Fractal Clonotype Distribution in the CD8+ Memory T Cell Repertoire Could Optimize Potential for Immune Responses
Authors: Naumov Yuri N. , Naumova Elena N. , Hogan Kevin T. , Selin Liisa K. , Gorski Jack
Published: April 2014

The nature of CD8+ T cell memory is still incompletely understood. We have previously reported that the response to an HLA-A2-restricted influenza-derived peptide results in a complex T cell repertoire. In this study we extend this analysis and describe the repertoire with more rigor. In one individual we defined 141 distinct T cell clonotypes on the basis of the unique DNA sequence of the third complementarity-determining region of the TCR β-chain. The frequency distribution of the clonotypes is not what is expected of a normal distribution but is characterized by a large low-frequency tail. The existence of a complex population indicates a mechanism for maintaining a large number of Ag-specific clonotypes at a low frequency in the memory pool. Ranking the clonotypes allowed us to describe the population in terms of a power law-like distribution with a parameter of decay of ∼1.6. If the repertoire is divided into subsets, such as clonotypes that use BJ2.7 or those whose third complementarity-determining region encodes the amino acid sequence IRSS, the clonotype frequencies could also be described by a power law-like distribution. This indicates a self similarity to the repertoire in which smaller pieces are slightly altered copies of the larger piece. The power law-like description is stable with time and was observed in a second individual. The distribution of clonotypes in the repertoire could be mapped onto a polygonal spiral using a recursive algorithm. Self similarity, power laws, and recursive mapping algorithms are associated with fractal systems. Thus, Ag-specific memory CD8 T cell repertoires can be considered as fractal, which could indicate optimized flexibility and robustness.
IL-1 Receptor-Associated Kinase 4 Is Essential for IL-18-Mediated NK and Th1 Cell Responses
Authors: Suzuki Nobutaka , Chen Nien-Jung , Millar Douglas G. , Suzuki Shinobu , Horacek Thomas , Hara Hiromitsu , Bouchard Denis , Nakanishi Kenji , Penninger Josef M. , Ohashi Pamela S. , Yeh Wen-Chen
Published: April 2014

IL-18 is an important cytokine for both innate and adaptive immunity. NK T cells and Th1 cells depend on IL-18 for their divergent functions. The IL-18R, IL-1R, and mammalian Toll-like receptors (TLRs) share homologous intracellular domains known as the TLR/IL-1R/plant R domain. Previously, we reported that IL-1R-associated kinase (IRAK)-4 plays a critical role in IL-1R and TLR signaling cascades and is essential for the innate immune response. Because TLR/IL-1R/plant R-containing receptors mediate signal transduction in a similar fashion, we investigated the role of IRAK-4 in IL-18R signaling. In this study, we show that IL-18-induced responses such as NK cell activity, Th1 IFN-γ production, and Th1 cell proliferation are severely impaired in IRAK-4-deficient mice. IRAK-4−/− Th1 cells also do not exhibit NF-κB activation or IκB degradation in response to IL-18. Moreover, AP-1 activation which is triggered by c-Jun N-terminal kinase activation is also completely inhibited in IRAK-4−/− Th1 cells. These results suggest that IRAK-4 is an essential component of the IL-18 signaling cascade.
Soluble Fibrinogen-Like Protein 2/Fibroleukin Exhibits Immunosuppressive Properties: Suppressing T Cell Proliferation and Inhibiting Maturation of Bone Marrow-Derived Dendritic Cells
Authors: Chan Camie W. Y. , Kay Lyndsey S. , Khadaroo Rachel G. , Chan Matthew W. C. , Lakatoo Sophia , Young Kevin J. , Zhang Li , Gorczynski Reginald M. , Cattral Mark , Rotstein Ori , Levy Gary A.
Published: April 2014

Fibrinogen-like protein 2 (fgl2)/fibroleukin is a member of the fibrinogen-related protein superfamily. In addition to its established role in triggering thrombosis, it is known to be secreted by T cells. The soluble fgl2 (sfgl2) protein generated in a baculovirus expression system bound to both T cells and bone marrow-derived dendritic cells (DC) in a specific manner. sfgl2 exhibited immunomodulatory properties capable of inhibiting T cell proliferation stimulated by alloantigens, anti-CD3/anti-CD28 mAbs, and Con A in a dose-dependent manner; however, it had no inhibitory effects on CTL activity. The time- and dose-dependent inhibitory effect of sfgl2 on alloreactive T cell proliferation could be neutralized by a mAb against mouse fgl2. Polarization toward a Th2 cytokine profile with decreased production of IL-2 and IFN-γ and increased production of IL-4 and IL-10 was observed in sfgl2-treated allogeneic cultures. Exposure of immature DC to sfgl2 abrogated the expression of CD80high and MHC class IIhigh molecules and markedly inhibited NF-κB nuclear translocation, thus inhibiting their maturation. sFgl2-treated DC had an impaired ability to stimulate allogeneic T cell proliferation. Maximal inhibition of proliferation was observed when allogeneic T cells were cultured with sfgl2-treated DC and sfgl2 protein was added in the culture. These data provide the first evidence to demonstrate that sfgl2 exerts immunosuppressive effects on T cell proliferation and DC maturation.
Regulation of Activin A Expression in Mast Cells and Asthma: Its Effect on the Proliferation of Human Airway Smooth Muscle Cells
Authors: Cho Seong H. , Yao Zhengbin , Wang Shen-Wu , Alban Rodrigo F. , Barbers Richard G. , French Samuel W. , Oh Chad K.
Published: April 2014

Activin A, a homodimeric protein (βAβA) and a member of the TGF-β superfamily, is involved in the inflammatory repair process. Using cDNA microarray analysis, we discovered strong induction of the activin βA gene in human mast cells (MC) on stimulation with PMA and calcium ionophore (A23187). Activin βA mRNA was also highly induced in primary cultured murine bone marrow MC (BMMC) after stimulation by IgE receptor cross-linking. Secretion of activin A was evident in human mast cell-1 line cells 3 h after stimulation and progressively increased over time. Activin A was present in the cytoplasm of activated but not unstimulated murine bone marrow MC as demonstrated by immunofluorescence studies, suggesting that secretion of activin A by MC was due to de novo synthesis rather than secretion of preformed protein. Activin A also colocalized with human lung MC from patients with asthma by double-immunofluorescence staining. Furthermore, secretion of activin A was significantly increased in the airway of wild-type mice after OVA sensitization followed by intranasal challenge. Secretion of activin A, however, was greatly reduced in MC-deficient WBB6F1-W/Wv mice as compared with wild-type mice, indicating that MC are an important contributor of activin A in the airways of a murine asthma model. Additionally, activin A promoted the proliferation of human airway smooth muscle cells. Taken together, these data suggest that MC-derived activin A may play an important role in the process of airway remodeling by promoting the proliferation of airway smooth muscle.
Expression of the NF-κB Target Gene X-Ray-Inducible Immediate Early Response Factor-1 Short Enhances TNF-α-Induced Hepatocyte Apoptosis by Inhibiting Akt Activation
Authors: Osawa Yosuke , Nagaki Masahito , Banno Yoshiko , Brenner David A. , Nozawa Yoshinori , Moriwaki Hisataka , Nakashima Shigeru
Published: April 2014

Using a cDNA microarray analysis, we identified x-ray-inducible immediate early response factor-1 (IEX-1) as a proapoptotic gene which was induced by TNF-α and also depend on NF-κB activation in Hc human hepatocytes. In these cells only the original form of IEX-1, termed IEX-1S, but not its longer transcript IEX-1L, was expressed. Overexpression of IEX-1S resulted in promotion of TNF-α-induced apoptosis in Hc cells expressing a mutant form of IκB. This proapoptotic action can be explained by its inhibitory findings on survival signals; inhibition of TNF-α-induced activation and expression of phosphatidylinositol 3-kinase (PI3K)/Akt, and also blockage of expression of Mcl-1, an antiapoptotic Bcl-2 family member which is located downstream of Akt, was inhibited by IEX-1S. LY 294002, an inhibitor of PI3K, increased IEX-1S expression induced by TNF-α and accelerated TNF-α-induced apoptosis in IκB-treated Hc cells. Overexpression of the dominant-negative Akt enhanced, but the constitutively active Akt suppressed, TNF-α-induced IEX-1S expression, suggesting that PI3K/Akt negatively regulated IEX-1S expression. These results demonstrate that NF-κB-dependent recruitment of IEX-1S may play a proapoptotic role in TNF-α-stimulated hepatocytes through blockage of the PI3K/Akt pathway. Moreover, the reciprocal cross-talk between IEX-1S and PI3K/Akt may closely be involved in the regulation of TNF-α-induced hepatocyte apoptosis.
Distinct Requirements for IL-7 in Development of TCRγδ Cells During Fetal and Adult Life
Authors: Laky Karen , Lewis Julia M. , Tigelaar Robert E. , Puddington Lynn
Published: April 2014

TCRγδ-transgenic IL-7−/− mice were generated to determine whether T cells containing productively rearranged TCRγδ genes have additional requirements for IL-7 within the thymus or peripheral lymphoid tissues. Differences in developmental requirements for IL-7 by TCRγδ cells were noted and were linked to derivation from fetal- vs adult-type precursors in the thymus. Although TCRγδ cells are absent from IL-7−/− mice, TCRγδ cells were restored to the thymus and periphery by expression of TCRγδ transgenes. Endogenous TCRγ chains were expressed by IL-7+/− but not IL-7−/− TCRγδ-transgenic mice, providing direct support for findings that IL-7 is necessary for rearrangement and expression of TCRγ genes. The number of TCRγδ thymocytes was 10-fold reduced in TCRγδ-transgenic IL-7−/− embryos; however, adult TCRγδ-transgenic IL-7−/− or IL-7+/− mice had similar numbers of fetal thymus-derived TCRγδ cells in their skin. Thus, fetal TCRγδ cells required IL-7 for TCR rearrangement, but not for proliferation or survival in the periphery. In contrast, the numbers of TCRγδ cells in other tissues of TCRγδ-transgenic IL-7−/− mice were not completely restored. Moreover, coincident with the transition from the first to second wave of T cell precursors maturing in neonatal thymus, thymus cellularity of TCRγδ-transgenic IL-7−/− mice dropped significantly. These data indicated that in addition to TCRVγ gene rearrangement, TCRγδ cells differentiating from late fetal liver or adult bone marrow precursors have additional requirements for IL-7. BrdU incorporation studies indicated that although IL-7 was not required for TCRγδ cell proliferation, it was required to prolong the life span of mature TCRγδ cells.
Regulation of T Cell Activation and Tolerance by Phospholipase Cγ-1-Dependent Integrin Avidity Modulation
Authors: Wells Andrew D. , Liu Qing-Hua , Hondowicz Brian , Zhang Jidong , Turka Laurence A. , Freedman Bruce D.
Published: April 2014

Ag receptor engagement without costimulation induces a tolerant state in CD4+ T cells termed anergy. Anergic CD4+ T cells are primarily characterized by the inability to produce IL-2, but the biochemical basis for this functional defect is not completely understood. We demonstrate that primary CD4+ T cells anergized by costimulatory blockade exhibit impaired TCR-coupled phospholipase C (PLC)γ-1 activation. This defect is associated with the marked reduction of multiple downstream signaling events required for IL-2 transcription, including mobilization of intracellular Ca2+ and activation of the mitogen-activated protein kinase cascade. We also found that primary anergic CD4+ T cells fail entirely to modulate their integrin binding avidity in response to TCR stimulation. Integrin avidity modulation is required for full T cell activation and effector function, and as we show in this study, is completely dependent upon PLCγ-1 activity. Finally, analogs that mimic the actions of diacylglycerol and inositol 1,4,5-triphosphate, the immediate products of PLCγ-1 activity, restored integrin avidity modulation and IL-2 production by anergic T cells. Thus, deficient coupling of PLCγ-1 to the TCR appears to be a central biochemical defect that could potentially account for the failure of multiple functional responses in primary anergic CD4+ T cells.
Communication Between NF-κB and Sp1 Controls Histone Acetylation Within the Proximal Promoter of the Monocyte Chemoattractant Protein 1 Gene
Authors: Boekhoudt Gunther H. , Guo Zhu , Beresford Guy W. , Boss Jeremy M.
Published: April 2014

The induction of the monocyte chemoattractant protein 1 gene (MCP-1) by TNF occurs through an NF-κB-dependent distal regulatory region and an Sp1-dependent proximal regulatory region that are separated by 2.2 kb of sequence. To investigate how these regions coordinate activation of MCP-1 in response to TNF, experiments were performed to examine the role of coactivators, changes in local chromatin structure, and the acetylation of histones at the MCP-1 regulatory regions. An E1a-sensitive coactivator was found to be required for expression. In vivo nuclease sensitivity assays identified changes in response to TNF at both the proximal and distal regions that were dependent on the p65 subunit of NF-κB and Sp1. Chromatin immunoprecipitations used to analyze factor assembly and histone acetylation at the distal and proximal regions showed that Sp1 binding to and histone acetylation of the proximal region was dependent on NF-κB p65. Conversely, Sp1 assembly at the proximal region was required for p65 binding to and acetylation of the distal region, suggesting communication between the two regions during gene activation. These data and the NF-κB p65-dependent histone acetylation of a middle region sequence suggest a potential order for the assembly, acetylation and accessibility of the MCP-1 regulatory regions in response to TNF.
Analysis of the TCR β Variable Gene Repertoire in Chimpanzees: Identification of Functional Homologs to Human Pseudogenes
Authors: Meyer-Olson Dirk , Brady Kristen W. , Blackard Jason T. , Allen Todd M. , Islam Sabina , Shoukry Naglaa H. , Hartman Kelly , Walker Christopher M. , Kalams Spyros A.
Published: April 2014

Chimpanzees are used for a variety of disease models such as hepatitis C virus (HCV) infection, where Ag-specific T cells are thought to be critical for resolution of infection. The variable segments of the TCR αβ genes are polymorphic and contain putative binding sites for MHC class I and II molecules. In this study, we performed a comprehensive analysis of genes that comprise the TCR β variable gene (TCRBV) repertoire of the common chimpanzee Pan troglodytes. We identified 42 P. troglodytes TCRBV sequences representative of 25 known human TCRBV families. BV5, BV6, and BV7 are multigene TCRBV families in humans and homologs of most family members were found in the chimpanzee TCRBV repertoire. Some of the chimpanzee TCRBV sequences were identical with their human counterparts at the amino acid level. Notably four successfully rearranged TCRBV sequences in the chimpanzees corresponded to human pseudogenes. One of these TCR sequences was used by a cell line directed against a viral CTL epitope in an HCV-infected animal indicating the functionality of this V region in the context of immune defense against pathogens. These data indicate that some TCRBV genes maintained in the chimpanzee have been lost in humans within a brief evolutionary time frame despite remarkable conservation of the chimpanzee and human TCRBV repertoires. Our results predict that the diversity of TCR clonotypes responding to pathogens like HCV will be very similar in both species and will facilitate a molecular dissection of the immune response in chimpanzee models of human diseases.
Threonine Phosphorylation Sites in the β2 and β7 Leukocyte Integrin Polypeptides
Authors: Hilden Tiina J. , Valmu Leena , Kärkkäinen Satu , Gahmberg Carl G.
Published: April 2014

The cytoplasmic domains of integrins play a key role in a variety of integrin-mediated events including adhesion, migration, and signaling. The molecular mechanisms that enhance integrin function are still incompletely understood. Because protein kinases are known to be involved in the signaling and the activation of integrins, the role of phosphorylation has been studied by several groups. The β2 leukocyte integrin subunit has previously been shown to become phosphorylated in leukocytes on cytoplasmic serine and functionally important threonine residues. We have now mapped the phosphorylated threonine residues in activated T cells. After phorbol ester stimulation, all three threonine residues (758–760) of the threonine triplet became phosphorylated but only two at a time. CD3 stimulation leads to a strong threonine phosphorylation of the β2 integrin, but differed from phorbol ester activation in that phosphorylation occurred only on threonine 758. The other leukocyte-specific integrin, β7, has also been shown to need the cytoplasmic domain and leukocyte-specific signal transduction elements for integrin activation. Cell activation with phorbol ester, and interestingly, through the TCR-CD3 complex, caused β7 integrin binding to VCAM-1. Additionally, cell activation led to increased phosphorylation of the β7 subunit, and phosphoamino acid analysis revealed that threonine residues became phosphorylated after cell activation. Sequence analysis by manual radiosequencing by Edman degradation established that threonine phosphorylation occurred in the same threonine triplet as in β2 phosphorylation.
Regulation of MHC Class I Transport in Human Dendritic Cells and the Dendritic-Like Cell Line KG-1
Authors: Ackerman Anne L. , Cresswell Peter
Published: April 2014

Dendritic cells (DCs) progress through distinct maturational phases; immature DCs capture Ag while mature DCs are optimized for Ag presentation. Proper control of immunity requires regulated compartmentalization of MHC class II molecules. We report that DCs also regulate MHC class I trafficking throughout maturation. Although mature human DCs express high levels of surface MHC class I, immature DCs exhibit lower surface levels while retaining MHC class I-peptide complexes in the Golgi. A cell line, KG-1, behaves similarly. We confirm the similarity of KG-1 to DCs by demonstrating its capacity to present exogenous Ags in an MHC class I-restricted fashion to CD8+ T cell hybridomas, a phenomenon called cross-presentation. Biochemical characterization of MHC class I trafficking throughout maturation showed that, in early KG-1 dendritic-like cells, surface arrival of MHC class I-peptide complexes is delayed by their retention in the Golgi. In mature dendritic-like cells, these complexes relocate to the surface and their stability increases, concomitant with up-regulation of costimulatory molecules. Maturation induces qualitative changes in the MHC class I-associated peptide repertoire demonstrated by increased thermostability. The differential processing of MHC class I throughout maturation may prevent premature immune activation while promoting T cell responses in lymph nodes to Ags acquired at sites of inflammation.
The FcRγ Subunit and Syk Kinase Replace the CD3ζ-Chain and ZAP-70 Kinase in the TCR Signaling Complex of Human Effector CD4 T Cells
Authors: Krishnan Sandeep , Warke Vishal G. , Nambiar Madhusoodana P. , Tsokos George C. , Farber Donna L.
Published: April 2014

The TCR-mediated signals required to activate resting T cells have been well characterized; however, it is not known how TCR-coupled signals are transduced in differentiated effector T cells that coordinate ongoing immune responses. Here we demonstrate that human effector CD4 T cells up-regulate the expression of the CD3ζ-related FcRγ signaling subunit that becomes part of an altered TCR/CD3 signaling complex containing CD3ε, but not CD3ζ. The TCR/CD3/FcRγ complex in effector cells recruits and activates the Syk, but not the ZAP-70, tyrosine kinase. This physiologic switch in TCR signaling occurs exclusively in effector, and not naive or memory T cells, suggesting a potential target for manipulation of effector responses in autoimmune, malignant, and infectious diseases.
Genetically Resistant Mice Lacking MyD88-Adapter Protein Display a High Susceptibility to Leishmania major Infection Associated with a Polarized Th2 Response
Authors: Muraille Eric , De Trez Carl , Brait Maryse , De Baetselier Patrick , Leo Oberdan , Carlier Yves
Published: April 2014

Host resistance to the intracellular protozoan Leishmania major is highly dependent on IL-12 production by APCs. Genetically resistant C57BL/6 mice develop IL-12-mediated Th1 immune response dominated by IFN-γ and exhibit only small cutaneous lesions that resolve spontaneously. In contrast, because of several genetic differences, BALB/c mice develop an IL-4-mediated Th2 immune response and a chronic mutilating disease. Myeloid differentiation marker 88 (MyD88) is an adaptator protein that links the IL-1/Toll-like receptor family to IL-1R-associated protein kinase. Toll-like receptors recognize pathogen associated molecular patterns and are crucially implicated in the induction of IL-12 secretion by APC. The role of MyD88 protein in the development of protective immune response against parasites is largely unknown. Following inoculation of L. major, MyD88−/− C57BL/6 mice presented large footpad lesions containing numerous infected cells and frequent mutilations. In response to soluble Leishmania Ag, cells from lesion-draining lymph node showed a typical Th2 profile, similar to infected BALB/c mice. IL-12p40 plasma level collapses in infected MyD88−/− mice compared with infected wild-type C57BL/6 mice. Importantly, administration of exogenous IL-12 rescues L. major-infected MyD88−/− mice, demonstrating that the susceptibility of these mice is a direct consequence of IL-12 deficiency. In conclusion, MyD88-dependent pathways appear essential for the development of the protective IL-12-mediated Th1 response against the Leishmania major parasite. In absence of MyD88 protein, infected mice develop a nonprotective Th2 response.
Decreased Stimulation of CD4+ T Cell Proliferation and IL-2 Production by Highly Enriched Populations of HIV-Infected Dendritic Cells
Authors: Kawamura Tatsuyoshi , Gatanaga Hiroyuki , Borris Debra L. , Connors Mark , Mitsuya Hiroaki , Blauvelt Andrew
Published: April 2014

APC infection and dysfunction may contribute to the immunopathogenesis of HIV disease. In this study, we examined immunologic function of highly enriched populations of HIV-infected monocyte-derived dendritic cells (DC). Compared with uninfected DC, HIV-infected DC markedly down-regulated surface expression of CD4. HIV p24+ DC were then enriched by negative selection of CD4+HIV p24− DC and assessed for cytokine secretion and immunologic function. Although enriched populations of HIV-infected DC secreted increased IL-12p70 and decreased IL-10, these cells were poor stimulators of allogeneic CD4+ T cell proliferation and IL-2 production. Interestingly, HIV-infected DC secreted HIV gp120 and the addition of soluble (s) CD4 (a known ligand for HIV gp120) to DC-CD4+ T cell cocultures restored T cell proliferation in a dose-dependent manner. By contrast, addition of antiretroviral drugs did not affect CD4+ T cell proliferation. Furthermore, recombinant HIV gp120 inhibited proliferation in uninfected cocultures of allogeneic DC and CD4+ T cells, an effect that was also reversed by addition of sCD4. In summary, we show that HIV gp120 produced by DC infected by HIV in vitro impairs normal CD4+ T cell function and that sCD4 completely reverses HIV gp120-mediated immunosuppression. We hypothesize that HIV-infected DC may contribute to impaired CD4+ T cell-mediated immune responses in vivo and that agents that block this particular immunosuppression may be potential immune adjuvants in HIV-infected individuals.
Persistence of Lesions in Suppressor of Cytokine Signaling-1-Deficient Mice Infected with Leishmania major
Authors: Bullen Denise V. R. , Baldwin Tracey M. , Curtis Joan M. , Alexander Warren S. , Handman Emanuela
Published: April 2014

To investigate the role of the cytokine IFN-γ and its negative regulator, the suppressor of cytokine signaling-1 (SOCS1) in the progression of cutaneous leishmaniasis, we infected mice lacking a single copy of the gene encoding SOCS1 (SOCS1+/−), mice lacking both copies of IFN-γ (IFN-γ−/−), or mice lacking copies of both SOCS1 and IFN-γ (SOCS1−/− IFN-γ−/−), with a moderate dose of 103 or 104 of the most virulent stage of parasites, metacyclic promastigotes. Surprisingly, SOCS1+/− mice developed larger lesions than wild-type mice, although the parasite load in the draining lymph node was not significantly altered. These mice also developed apparently normal Th1 responses, as indicated by elevated levels of IFN-γ and low levels of IL-4 and IL-10. The persistence of lesions and the enlargement of draining lymph nodes despite a normal Th1 response and control of parasitemia indicate that there may be a dissociation of the inflammatory pathology and clearance of parasites in SOCS1+/− mice. We also investigated the role of the related suppressor of cytokine signaling, SOCS2, which has been implicated in the development of Th1 immunity. The progression of disease in SOCS2−/− mice did not differ from that in C57BL/6 control mice, suggesting that it is not involved in the host response to Leishmania major infection and supporting the specific role of SOCS1. These results suggest that SOCS1 plays an important role in the regulation of appropriate inflammatory responses during the resolution of L. major infection.
Transient Neutrophil Infiltration After Allergen Challenge Is Dependent on Specific Antibodies and FcγIII Receptors
Authors: Taube Christian , Dakhama Azzeddine , Rha Yeong-Ho , Takeda Katsuyuki , Joetham Anthony , Park Jung-Won , Balhorn Annette , Takai Toshiyuki , Poch Katie R. , Nick Jerry A. , Gelfand Erwin W.
Published: April 2014

Following allergen challenge of sensitized mice, neutrophils are the first inflammatory cells found in bronchoalveolar lavage (BAL) fluid. To determine the underlying mechanism for their accumulation, mice were sensitized to OVA on days 0 and 14, and received, on day 28, a single intranasal challenge (s.i.n.) with either OVA or ragweed. Eight hours after the s.i.n., BAL fluid was obtained. BALB/c mice sensitized and challenged with OVA showed significantly higher total cell counts and numbers of neutrophils in BAL fluid compared to the OVA-sensitized and ragweed-challenged or nonsensitized mice. Levels of neutrophil chemokines in BAL fluid supernatants were markedly elevated in the sensitized and OVA-challenged mice; FcεRI-deficient mice showed comparable numbers of neutrophils and neutrophil chemokines in BAL fluid after s.i.n. But in sensitized mice lacking the Fc common γ-chain and B cell-deficient mice, the number of neutrophils and levels of neutrophil chemokines in BAL fluid were significantly lower. Further, mice lacking the FcγRIII did not develop this early neutrophil influx. Neutrophil infiltration could be induced in naive mice following intranasal instillation of allergen combined with allergen-specific IgG1. In addition, macrophages from sensitized mice were stimulated with allergen and activated to produce neutrophil chemokines. These results demonstrate that neutrophil influx after allergen challenge requires prior sensitization, is allergen-specific, is mediated through FcγRIII, and is dependent on the presence of Ab.
A Peptide Derived from the Parasite Receptor, Complement C2 Receptor Inhibitor Trispanning, Suppresses Immune Complex-Mediated Inflammation in Mice
Authors: Inal Jameel M. , Schneider Brigitte , Armanini Marta , Schifferli Jürg A.
Published: April 2014

Complement C2 receptor inhibitor trispanning (CRIT) is a Schistosoma protein that binds the human complement protein, C2. We recently showed that peptides based on the ligand binding region of CRIT inhibit the classical pathway (CP) of complement activation in human serum, using hemolytic assays and so speculated that on the parasite surface CRIT has the function of evading human complement. We now show that in vitro the C2-binding 11-aa C terminus of the first extracellular domain of CRIT, a 1.3-kDa peptide termed CRIT-H17, inhibits CP activation in a species-specific manner, inhibiting mouse and rat complement but not that from guinea pig. Hitherto, the ability of CRIT to regulate complement in vivo has not been assessed. In this study we show that by inhibiting the CP, CRIT-H17 is able to reduce immune complex-mediated inflammation (dermal reversed passive Arthus reaction) in BALB/c mice. Upon intradermal injection of CRIT-H17, and similarly with recombinant soluble complement receptor type 1, there was a 41% reduction in edema and hemorrhage, a 72% reduction in neutrophil influx, and a reduced C3 deposition. Furthermore, when H17 was administered i.v. at a 1 mg/kg dose, inflammation was reduced by 31%. We propose that CRIT-H17 is a potential therapeutic agent against CP complement-mediated inflammatory tissue destruction.
Essential Role of Fcγ Receptors in Anti-Type II Collagen Antibody-Induced Arthritis
Authors: Kagari Takashi , Tanaka Daisuke , Doi Hiromi , Shimozato Takaichi
Published: April 2014

Anti-type II collagen (anti-CII) Ab is a well-known autoantibody observed in patients with rheumatoid arthritis. Injection of anti-CII Ab and LPS induces arthritis in mice in which anti-CII Ab as well as inflammatory cytokines, IL-1β and TNF-α, play critical roles. We investigated the involvement of IgG FcRs (FcγRs) in this arthritis model. BALB/c mice injected with the F(ab′)2 of anti-CII Ab showed no signs of arthritis. Arthritis development was not observed in FcRγ−/− mice and was partially suppressed in FcγRIII−/− mice despite the binding of anti-CII Ab and C3 to cartilage surface. Surprisingly, BALB/c mice lacking FcγRIIB, which is known as an inhibitory FcγR, developed arthritis with no exacerbation in arthritis score compared with wild-type (WT) mice, and only slight exacerbation was observed in the histopathological analysis. In contrast, aged FcγRIIB−/− BALB/c mice developed arthritis without LPS injection, suggesting an augmented susceptibility to arthritis in aged FcγRIIB−/− mice. No significant difference was observed among BALB/c-WT, -FcRγ−/−, and -FcγRIIB−/− mice on cytokine production induced by anti-CII Ab and LPS injection. Severe arthritis developed in BALB/c-WT and -FcγRIIB−/− mice, but not in BALB/c-FcRγ−/− mice, after the injection of anti-CII Ab and inflammatory cytokines. These results suggest that the reason behind the nondevelopment of arthritis in FcRγ−/− BALB/c mice is not due to a disorder in transient cytokine production, but to an irregularity downstream of cytokine production.
L-Selectin or ICAM-1 Deficiency Reduces an Immediate-Type Hypersensitivity Response by Preventing Mast Cell Recruitment in Repeated Elicitation of Contact Hypersensitivity
Authors: Shimada Yuka , Hasegawa Minoru , Kaburagi Yuko , Hamaguchi Yasuhito , Komura Kazuhiro , Saito Eriko , Takehara Kazuhiko , Steeber Douglas A. , Tedder Thomas F. , Sato Shinichi
Published: April 2014

Repeated Ag exposure results in a shift in the time course of contact hypersensitivity (CH) from a typical delayed-type to an immediate-type response followed by a late phase reaction. Chronic CH responses are clinically relevant to human skin allergic diseases, such as atopic dermatitis, that are usually caused by repeated stimulation with environmental Ags. Chronic inflammatory responses result in part from infiltrating leukocytes. To determine the role of leukocyte adhesion molecules in chronic inflammation, chronic CH responses were assessed in mice lacking L-selectin, ICAM-1, or both adhesion molecules. Following repeated hapten sensitization for 24 days at 2-day intervals, wild-type littermates developed an immediate-type response at 30 min after elicitation, followed by a late phase reaction. By contrast, loss of ICAM-1, L-selectin, or both, eliminated the immediate-type response and inhibited the late phase reaction. Similar results were obtained when wild-type littermates repeatedly exposed to hapten for 22 days were treated with mAbs to L-selectin and/or ICAM-1 before the elicitation on day 24. The lack of an immediate-type response on day 24 paralleled a lack of mast cell accumulation after 30 min of elicitation and decreased serum IgE production. Repeated Ag exposure in wild-type littermates resulted in increased levels of serum L-selectin, a finding also observed in atopic dermatitis patients. The current study demonstrates that L-selectin and ICAM-1 cooperatively regulate the induction of the immediate-type response by mediating mast cell accumulation into inflammatory sites and suggests that L-selectin and ICAM-1 are potential therapeutic targets for regulating human allergic reactions.
Neutrophil Restraint by Green Tea: Inhibition of Inflammation, Associated Angiogenesis, and Pulmonary Fibrosis
Authors: Donà Massimo , Dell’Aica Isabella , Calabrese Fiorella , Benelli Roberto , Morini Monica , Albini Adriana , Garbisa Spiridione
Published: April 2014

Neutrophils play an essential role in host defense and inflammation, but the latter may trigger and sustain the pathogenesis of a range of acute and chronic diseases. Green tea has been claimed to exert anti-inflammatory properties through unknown molecular mechanisms. We have previously shown that the most abundant catechin of green tea, (−)epigallocatechin-3-gallate (EGCG), strongly inhibits neutrophil elastase. Here we show that 1) micromolar EGCG represses reactive oxygen species activity and inhibits apoptosis of activated neutrophils, and 2) dramatically inhibits chemokine-induced neutrophil chemotaxis in vitro; 3) both oral EGCG and green tea extract block neutrophil-mediated angiogenesis in vivo in an inflammatory angiogenesis model, and 4) oral administration of green tea extract enhances resolution in a pulmonary inflammation model, significantly reducing consequent fibrosis. These results provide molecular and cellular insights into the claimed beneficial properties of green tea and indicate that EGCG is a potent anti-inflammatory compound with therapeutic potential.
T Cell Immunity to Herpes Simplex Viruses in Seronegative Subjects: Silent Infection or Acquired Immunity?
Authors: Posavad Christine M. , Wald Anna , Hosken Nancy , Huang Meei Li , Koelle David M. , Ashley Rhoda L. , Corey Lawrence
Published: April 2014

During the course of investigating T cell responses to HSV among volunteers entering trials of investigational genital herpes vaccines, 6 of the 24 immunocompetent subjects with no prior history of oral/labial or genital herpes possessed HSV-specific T cell immunity but, by multiple determinants of even the most sensitive serological assays, remained seronegative to HSV-1 and -2. Of these six immune seronegative (IS; HSV-seronegative with HSV-specific T cell responses) subjects, two had transient HSV-specific T cell responses, while four had CD4+ and CD8+ T cell responses directed at HSV that persisted for up to 4 years. CD4+ T cell clones were isolated that recognized and had high binding affinities to epitopes in HSV-2 tegument proteins. All six IS subjects had potential sexual exposure to an HSV-2-infected sexual partner. Oral and genital mucosal secretions were sampled and tested for the presence of infectious HSV and HSV DNA. No evidence of HSV was detected in >1500 samples obtained from these IS subjects. The identification of persistent T cell responses to HSV in seronegative subjects is a novel finding in the herpesvirus field and suggests either undetected infection or acquired immunity in the absence of infection. Understanding the basis of these acquired immune responses may be critical in developing effective vaccines for genital herpes.