bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased Expression of Ifi202, an IFN-Activatable Gene, in B6.Nba2 Lupus Susceptible Mice Inhibits p53-Mediated Apoptosis
Authors: Xin Hong , D’Souza Sanjay , Jørgensen Trine N. , Vaughan Andrew T. , Lengyel Peter , Kotzin Brian L. , Choubey Divaker 
Published: April 2014

Abstract
Increased expression of p202 protein (encoded by the Ifi202 gene) in splenocytes derived from B6.Nba2 mice (congenic for the Nba2 interval derived from the New Zealand Black mice) was correlated with defects in apoptosis of splenic B cells and increased susceptibility to develop systemic lupus erythematosus. We have now investigated the molecular mechanisms by which increased expression of p202 in B6.Nba2 cells contributes to defects in apoptosis. In this study, we report that increased expression of p202 in the B6.Nba2 splenocytes, as compared with cells derived from the parental C57BL/6 (B6) mice, was correlated with increased levels of p53 protein and inhibition of p53-mediated transcription of target genes that encode proapoptotic proteins. Conversely, knockdown of p202 expression in B6.Nba2 cells resulted in stimulation of p53-mediated transcription. We found that p202 bound to p53 in the N-terminal region (aa 44–83) comprising the proline-rich region that is important for p53-mediated apoptosis. Consistent with the binding of p202 to p53, increased expression of p202 in B6.Nba2 mouse embryonic fibroblasts inhibited UV-induced apoptosis. Taken together, our observations support the idea that increased expression of p202 in B6.Nba2 mice increases the susceptibility to develop lupus, in part, by inhibiting p53-mediated apoptosis.
Expression of TCRαβ Partly Rescues Developmental Arrest and Apoptosis of αβ T cells in Bcl11b−/− Mice
Authors: Inoue Jun , Kanefuji Tsutomu , Okazuka Kiyoshi , Watanabe Hisami , Mishima Yukio , Kominami Ryo 
Published: April 2014

Abstract
Bcl11b −/− mice show developmental arrest at the CD44−CD25+ double-negative 3 (DN3) or immature CD8+single-positive stage of αβ T cell. We have performed detailed analysis of sorted subsets of Bcl11b−/− thymocytes, DN3 and CD44−CD25− double-negative 4 (DN4) cells. Surface expression of TCRβ proteins was not detected in DN3 thymocytes and markedly reduced in DN4 thymocytes, whereas expression within the cell was detected in both, suggesting some impairment in processing of TCRβ proteins from the cytoplasm to the cell surface. This lack of expression, resulting in the absence of pre-TCR signaling, could be responsible for the arrest, but the transgenic TCRβ or TCRαβ expression on the cell surface failed to promote transition from the DN3 to CD4+CD8+ double-positive stage of development. This suggests that the pre-TCR signal cannot compensate the deficiency of Bcl11b for development. Bcl11b−/− DN3 thymocytes showed normal DNA rearrangements between Dβ and Jβ segments but limited DNA rearrangements between Vβ and DJβ without effect of distal or proximal positions. Because this impairment may be due to chromatin accessibility, we have examined histone H3 acetylation in Bcl11b−/− DN3 cells using chromatin immunoprecipitation assay. No change was observed in acetylation at the Vβ and Dβ gene locus. Analysis of Bcl11b−/− DN4 thymocytes showed apoptosis, accompanied with lower expression of anti-apoptotic proteins, Bcl-xL and Bcl-2, than wild-type DN4 thymocytes. Interestingly, the transgenic TCRαβ in those cells reduced apoptosis and raised their protein expression without increased cellularity. These results suggest that Bcl11b deficiency affects many different signaling pathways leading to development arrests.
Arginine Transport via Cationic Amino Acid Transporter 2 Plays a Critical Regulatory Role in Classical or Alternative Activation of Macrophages
Authors: Yeramian Andrée , Martin Lorena , Serrat Neus , Arpa Luis , Soler Concepció , Bertran Joan , McLeod Carol , Palacín Manuel , Modolell Manuel , Lloberas Jorge , Celada Antonio 
Published: April 2014

AbstractArginine is processed by macrophages in response to the cytokines to which these cells are exposed. Th1-type cytokines induce NO synthase 2, which metabolizes arginine into nitrites, while the Th2-type cytokines produce arginase, which converts arginine into polyamines and proline. Activation of bone marrow-derived macrophages by these two types of cytokines increases l-arginine transport only through the y+ system. Analysis of the expression of the genes involved in this system showed that Slc7A1, encoding cationic amino acid transporters (CAT)1, is constitutively expressed and is not modified by activating agents, while Slc7A2, encoding CAT2, is induced during both classical and alternative activation. Macrophages from Slc7A2 knockout mice showed a decrease in l-arginine transport in response to the two kinds of cytokines. However, while NO synthase 2 and arginase expression were unmodified in these cells, the catabolism of arginine was impaired by both pathways, producing smaller amounts of nitrites and also of polyamines and proline. In addition, the induction of Slc7A2 expression was independent of the arginine available and of the enzymes that metabolize it. In conclusion, the increased arginine transport mediated by activators is strongly regulated by CAT2 expression, which could limit the function of macrophages.
Targeting Melanoma Cells with Human High Molecular Weight-Melanoma Associated Antigen-Specific Antibodies Elicited by a Peptide Mimotope: Functional Effects
Authors: Luo Wei , Ko Eric , Hsu Jeff Chi-feng , Wang Xinhui , Ferrone Soldano 
Published: April 2014

Abstract
Human high molecular weight-melanoma associated Ag (HMW-MAA) mimics have been shown to elicit HMW-MAA-specific humoral immune responses that appear to be clinically beneficial. This finding has stimulated interest in characterizing the mechanism(s) underlying the ability of the elicited Abs to exert an anti-tumor effect. To address this question, in the present study, we have generated HMW-MAA-specific Abs by sequentially immunizing rabbits with the peptide P763.74, which mimics the HMW-MAA determinant recognized by mAb 763.74, and with HMW-MAA+ melanoma cells. HMW-MAA-specific Abs isolated from immunized rabbits mediated cell-dependent cytotoxicity but did not mediate complement-dependent cytotoxicity of HMW-MAA+ melanoma cells. These Abs also effectively inhibited spreading, migration and Matrigel invasion of HMW-MAA+ melanoma cells. Besides contributing to our understanding of the role of HMW-MAA in the biology of melanoma cells, these results suggest that both immunological and nonimmunological mechanisms underlie the beneficial clinical effects associated with the induction of HMW-MAA-specific Abs in melanoma patients immunized with a HMW-MAA mimic.
The Proteasome Pathway Destabilizes Yersinia Outer Protein E and Represses Its Antihost Cell Activities
Authors: Ruckdeschel Klaus , Pfaffinger Gudrun , Trülzsch Konrad , Zenner Gerhardt , Richter Kathleen , Heesemann Jürgen , Aepfelbacher Martin 
Published: April 2014

Abstract
Pathogenic Yersinia spp. neutralize host defense mechanisms by engaging a type III protein secretion system that translocates several Yersinia outer proteins (Yops) into the host cell. Although the modulation of the cellular responses by individual Yops has been intensively studied, little is known about the fate of the translocated Yops inside the cell. In this study, we investigated involvement of the proteasome, the major nonlysosomal proteolytic system in eukaryotic cells, in Yop destabilization and repression. Our data show that inhibition of the proteasome in Yersinia enterocolitica-infected cells selectively stabilized the level of YopE, but not of YopH or YopP. In addition, YopE was found to be modified by ubiquitination. This suggests that the cytotoxin YopE is physiologically subjected to degradation via the ubiquitin-proteasome pathway inside the host cell. Importantly, the increased levels of YopE upon proteasome inhibition were associated with decreased activity of its cellular target Rac. Thus, the GTPase-down-regulating function of YopE is enhanced when the proteasome is inhibited. The stabilization of YopE by proteasome inhibitor treatment furthermore led to aggravation of the cytotoxic YopE effects on the actin cytoskeleton and on host cell morphology. Together, these data show that the host cell proteasome functions to destabilize and inactivate the Yersinia effector protein YopE. This implies the proteasome as integral part of the cellular host immune response against the immunomodulatory activities of a translocated bacterial virulence protein.
Defective Adhesion in Tumor Infiltrating CD8+ T Cells
Authors: Koneru Mythili , Monu Ngozi , Schaer David , Barletta Justine , Frey Alan B. 
Published: April 2014

Abstract
CD8+ tumor-infiltrating lymphocytes (TIL) are defective in cytolysis due to tumor-induced inhibition of proximal TCR-mediated signaling, a defect that is relieved upon purification and brief culture. We show in this study that frequency of conjugation in vitro of nonlytic TIL with tumor cells is low in comparison with their lytic counterparts, and the strength of interaction and duration of conjugation are also reduced. Previous reports show that p56lck activation is required for TCR-initiated LFA-1 avidity up-regulation, raising the question: is low LFA-1 avidity the basis of reduced TIL conjugation frequency? When stimulated with phorbol ester, nonlytic TIL bind purified ICAM-1 equivalently as lytic TIL, suggesting that LFA-1 can be activated if proximal TCR signaling is bypassed. However, when treated with phorbol ester, the conjugation frequency of nonlytic TIL does not increase. CD2 and CD8 also mediate T cell adhesion to cognate target cells and are both expressed at lower levels in nonlytic TIL in addition to being excluded from the immune synapse formed upon conjugation. Collectively, these results imply that adhesion defects in nonlytic TIL result from a combination of decreased cell surface levels of adhesion molecules, deficient LFA-1 activation, and the failure to recruit essential adhesion receptors to the membrane contact site formed with cognate target cells.
Roles of the Alternative Complement Pathway and C1q during Innate Immunity to Streptococcus pyogenes
Authors: Yuste Jose , Ali Sifot , Sriskandan Shiranee , Hyams Catherine , Botto Marina , Brown Jeremy S. 
Published: April 2014

Abstract
Complement is important for innate immunity to the common bacterial pathogen Streptococcus pyogenes, but the relative importance of the alternative and classical pathways has not been investigated. Using mice and human serum deficient in either C1q, the first component of the classical pathway, or factor B, an important component of the alternative pathway, we have investigated the role of both pathways for innate immunity to S. pyogenes. C3b deposition on four different strains of S. pyogenes was mainly dependent on factor B. As a consequence opsonophagocytosis of S. pyogenes was reduced in serum from factor B-deficient mice, and these mice were very susceptible to S. pyogenes infection. In contrast, C3b deposition was not dependent on C1q for two of the strains investigated, H372 and H305, yet opsonophagocytosis of all four S. pyogenes strains was impaired in serum deficient in C1q. Furthermore, infection in C1q-deficient mice with strain H372 resulted in a rapidly progressive disease associated with large numbers of bacteria in target organs. These results demonstrate the important role of the alternative pathway and C1q for innate immunity to S. pyogenes and suggest that C1q-mediated innate immunity to at least some strains of S. pyogenes may involve mechanisms that are independent of C3b on the bacteria.
CD94/NKG2A Expression Is Associated with Proliferative Potential of CD8 T Cells during Persistent Polyoma Virus Infection
Authors: Byers Anthony M. , Andrews Nicolas P. , Lukacher Aron E. 
Published: April 2014

Abstract
Memory CD8 T cells comprise a critical component of durable immunity because of their capacity to rapidly proliferate and exert effector activity upon Ag rechallenge. During persistent viral infection, memory CD8 T cells repetitively encounter viral Ag and must maintain a delicate balance between limiting viral replication and minimizing immunopathology. In mice infected by polyoma virus, a natural mouse pathogen that establishes long-term persistent infection, the majority of persistence-phase antiviral CD8 T cells express the inhibitory NK cell receptor CD94/NKG2A. In this study, we asked whether CD94/NKG2A expression is associated with Ag-specific recall of polyoma virus-specific CD8 T cells. During the persistent phase of infection, polyoma virus-specific CD8 T cells that express CD94/NKG2A were found to preferentially proliferate; this proliferation was dependent on cognate Ag both in vitro and in vivo. In addition, CD94/NKG2A+ polyoma-specific CD8 T cells have a markedly enhanced capacity to produce IL-2 upon ex vivo Ag stimulation compared with CD94/NKG2A− polyoma-specific CD8 T cells. Importantly, CD94/NKG2A+ anti-polyoma virus CD8 T cells appear to be essential for Ag-specific recall responses in mice persistently infected by polyoma virus. Because of its higher proliferative potential and capacity to produce IL-2, we propose that the CD94/NKG2A+ subpopulation represents a less differentiated state than the CD94/NKG2A− subpopulation. Identification of proliferation-competent subpopulations of memory CD8 T cells should prove valuable in designing therapeutic vaccination strategies for persistent viral infections.
MyD88-Dependent IFN-γ Production by NK Cells Is Key for Control ofLegionella pneumophilaInfection
Authors: Spörri Roman , Joller Nicole , Albers Urs , Hilbi Hubert , Oxenius Annette 
Published: April 2014

AbstractLegionella pneumophila (Lpn) is a ubiquitous Gram-negative bacterium in aquatic systems and an opportunistic intracellular pathogen in immunocompromised humans causing a severe pneumonia known as Legionnaires’ disease. Using a mouse model, we investigated molecular and cellular players in the innate immune response to infection with Lpn. We observed robust levels of inflammatory cytokines in the serum upon intranasal or i.v. infection with live, virulent Lpn, but not with inactivated or avirulent bacteria lacking the Icm/Dot type IV secretion system. Interestingly, Lpn-induced serum cytokines were readily detectable regardless of the capacity of Icm/Dot-proficient Lpn to replicate in host cells and the Lpn permissiveness of the host mice. We found NK cell-derived IFN-γ to be the key cytokine in the resolution of Lpn infection, whereas type I IFNs did not appear to play a major role in our model. Accordingly, NK cell-depleted or IFN-II-R-deficient mice carried severely increased bacterial burdens or failed to control Lpn infection, respectively. Besides the dependence of inflammatory cytokine induction on Lpn virulence, we also demonstrate a strict requirement of MyD88 for this process, suggesting the involvement of TLRs in the recognition of Lpn. However, screening of several TLR-deficient hosts did not reveal a master TLR responsible for the sensing of an Lpn infection, but provided evidence for either redundancy of individual TLRs in Lpn recognition or TLR-independent induction of inflammatory responses.
Immature Human Dendritic Cells Infected with Leishmania infantum Are Resistant to NK-Mediated Cytolysis but Are Efficiently Recognized by NKT Cells
Authors: Campos-Martín Yolanda , Colmenares María , Gozalbo-López Beatriz , López-Núñez Marta , Savage Paul B. , Martínez-Naves Eduardo 
Published: April 2014

Abstract
Dendritic cells (DC) play an important role in innate and adaptive immunity, interacting with T cells, NK, and NKT cells. A critical step in the interaction of the parasitic protozoa Leishmania with their host is the evasion of both innate and adaptive immunity, producing a long-lasting chronic infection. There is growing evidence that these parasites can modify the Ag-presenting and immunoregulatory functions of DCs. The cells and mechanisms involved in innate immune response against Leishmania are still poorly understood. In this study, we investigated how Leishmania infantum infection affects DC interactions with NK and invariant NKT (iNKTs) cells in humans. We found that infected immature DCs (iDCs) do not up-regulate HLA class I molecules. Despite this, iDCs become resistant to killing mediated by autologous NK cells due to the up-regulation of HLA-E expression, which protects target cells from NK-mediated lysis through interaction with the inhibitory receptor CD94/NKG2A. Furthermore, iDCs infected with L. infantum up-regulate CD1d cell surface expression and consequently can be efficiently recognized and killed by iNKT cells that produce IFN-γ. These data suggest that L. infantum could be able to evade NK recognition; in contrast, iNKTs may play an important role in the immune response against Leishmania.
Reevaluation of P-Selectin and α4 Integrin as Targets for the Treatment of Experimental Autoimmune Encephalomyelitis
Authors: Kerfoot Steven M. , Norman M. Ursula , Lapointe Benoit M. , Bonder Claudine S. , Zbytnuik Lori , Kubes Paul 
Published: April 2014

AbstractThere has been a great deal of interest in adhesion molecules as targets for the treatment of multiple sclerosis and other inflammatory diseases. In this study, we systematically evaluate α4 integrin and P-selectin as targets for therapy in murine models of multiple sclerosis–for the first time directly measuring the ability of their blockade to inhibit recruitment and relate this to clinical efficacy. Experimental autoimmune encephalomyelitis was induced in C57BL/6 or SJL/J mice and intravital microscopy was used to quantify leukocyte interactions within the CNS microvasculature. In both strains, pretreatment with blocking Abs to either α4 integrin or P-selectin reduced firm adhesion to a similar extent, but did not block it completely. The combination of the Abs was more effective than either Ab alone, although the degree of improvement was more evident in SJL/J mice. Similarly, dual blockade was much more effective at preventing the subsequent accumulation of fluorescently labeled leukocytes in the tissue in both strains. Despite evidence of blockade of leukocyte recruitment mechanisms, no clinical benefit was observed with anti-adhesion molecule treatments or genetic deletion of P-selectin in the C57BL/6 model, or in a pertussis toxin-modified model in SJL/J mice. In contrast, Abs to α4 integrin resulted in a significant delay in the onset of clinical signs of disease in the standard SJL/J model. Despite evidence of a similar ability to block firm adhesion, Abs to P-selectin had no effect. Importantly, combined blockade of both adhesion molecules resulted in significantly better clinical outcome than anti-α4 integrin alone.
Fas Ligand Is Responsible for CXCR3 Chemokine Induction in CD4+ T Cell-Dependent Liver Damage
Authors: Cruise Michael W. , Lukens John R. , Nguyen Aileen P. , Lassen Matthew G. , Waggoner Stephen N. , Hahn Young S. 
Published: April 2014

Abstract
Immune-mediated hepatic damage has been demonstrated in the pathogenesis of hepatitis C virus (HCV) and other hepatotrophic infections. Fas/Fas ligand (FasL) interaction plays a critical role in immune-mediated hepatic damage. To understand the molecular mechanism(s) of FasL-mediated liver inflammation, we examined the effect of CD4+ T cells expressing high levels of FasL on the initiation of hepatic damage through analysis of chemokine and chemokine receptor expression in HCV core × TCR (DO11.10) double-transgenic mice. In vivo antigenic stimulation triggers a marked influx of core-expressing Ag-specific CD4+ T cells into the liver of the immunized core+ TCR mice but not their core− TCR littermates. Strikingly, the inflammatory process in the liver of core+ TCR mice was accompanied by a dramatic increase in IFN-inducible protein 10 and monokine induced by IFN-γ production. The intrahepatic lymphocytes were primarily CXCR3-positive and anti-CXCR3 Ab treatment abrogates migration of CXCR3+ lymphocytes into the liver and hepatic damage. Importantly, the blockade of Fas/FasL interaction reduces the expression of IFN-inducible protein 10 and monokine induced by IFN-γ and cellular infiltration into the liver. These findings suggest that activated CD4+ T cells with elevated FasL expression are involved in promoting liver inflammation and hepatic damage through the induction of chemokines.
Control of Metastasized Pancreatic Carcinomas in SCID/Beige Mice with Human IL-2/TKD-Activated NK Cells
Authors: Stangl Stefan , Wortmann Andreas , Guertler Ulrich , Multhoff Gabriele 
Published: April 2014

AbstractPancreatic carcinoma, the fifth leading cause of cancer-related mortality, frequently presents the stress-inducible heat shock protein 70 (Hsp70) on the cell membrane. Therefore, we explored an immunological approach exploiting the efficacy of NK cells activated either with low dose IL-2 plus Hsp70-peptide TKDNNLLGRFELSG (TKD; IL-2/TKD) or with IL-2 alone in a xenograft pancreatic carcinoma model. An orthotopic injection of either 2.5 × 106 or 1 × 106 Colo357 cells in SCID/beige mice resulted in rapidly growing primary tumors and the development of hepatic metastases on days 5 and 10, respectively. In line with results of in vitro migration assays, these NK cells also had the capacity to infiltrate pancreatic tumors and liver metastases in tumor-bearing mice. In vitro, a combined treatment of NK cells with IL-2/TKD but neither of the two treatments alone causes a profound increase in the lytic capacity against Hsp70 membrane-positive Colo357 cells. In vivo, a single i.v. injection of these NK cells on day 15 post-tumor inoculation resulted in a significant reduction in tumor weights, a delayed onset of hepatic metastases, and a prolonged life expectancy. In contrast, identically treated T cells and NK cells treated with IL-2 alone were significantly less efficient in controlling pancreatic tumors and metastases. Most importantly, four repeated i.v. infusions of IL-2/TKD-activated NK cells eradicated primary tumors and prevented hepatic metastases. In summary, our mouse data have implicated that NK cells preactivated with IL-2/TKD might provide a novel therapeutic tool for the treatment of aggressive, Hsp70-positive pancreatic carcinoma.
TNF-α Is Necessary for Induction of Coronary Artery Inflammation and Aneurysm Formation in an Animal Model of Kawasaki Disease
Authors: Hui-Yuen Joyce S. , Duong Trang T. , Yeung Rae S. M. 
Published: April 2014

Abstract
Kawasaki disease is the most common cause of multisystem vasculitis in childhood. The resultant coronary artery lesions make Kawasaki disease the leading cause of acquired heart disease in children in the developed world. TNF-α is a pleiotropic inflammatory cytokine elevated during the acute phase of Kawasaki disease. In this study, we report rapid production of TNF-α in the peripheral immune system after disease induction in a murine model of Kawasaki disease. This immune response becomes site directed, with migration to the coronary arteries dependent on TNF-α-mediated events. Production of TNF-α in the heart is coincident with the presence of inflammatory infiltrate at the coronary arteries, which persists during development of aneurysms. More importantly, inflammation and elastin breakdown in the coronary vessels are completely eliminated in the absence of TNF-α effector functions. Mice treated with the TNF-α-blocking agent etanercept, as well as TNFRI knockout mice, are resistant to development of both coronary arteritis and coronary aneurysm formation. Taken together, TNF-α is necessary for the development of coronary artery lesions in an animal model of Kawasaki disease. These findings have important implications for potential new therapeutic interventions in children with Kawasaki disease.