bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ikaros Null Mice Display Defects in T Cell Selection and CD4 versus CD8 Lineage Decisions
Authors: Urban Julie A. , Winandy Susan 
Published: April 2014

Abstract
Previous evidence suggested that the hemopoietic-specific nuclear factor Ikaros regulates TCR signaling thresholds in mature T cells. In this study, we test the hypothesis that Ikaros also sets TCR signaling thresholds to regulate selection events and CD4 vs CD8 lineage determination in developing thymocytes. Ikaros null mice were crossed to three lines of TCR-transgenic mice, and positive selection, negative selection, and CD4 vs CD8 lineage decisions were analyzed. Mice expressing a polyclonal repertoire or a MHC class II-restricted TCR transgene exhibited enhanced positive selection toward the CD4 lineage. Moreover, in the absence of Ikaros, CD4 development can occur with decreased thresholds of TCR signaling. In addition, CD4 single-positive thymocytes were detected in MHC class I-restricted TCR-transgenic Ikaros null mice. To assess the role of Ikaros in negative selection, we analyzed deletion of T cells induced by conventional Ag or by endogenous superantigen. Surprisingly, negative selection was impaired in Ikaros null thymocytes despite evidence of high levels of TCR signal and no intrinsic defect in apoptosis ex vivo. To our knowledge, these data identify Ikaros as the first nuclear factor that plays a critical role in regulating negative selection as well as CD4 vs CD8 lineage decisions during positive selection.
Aged Mice Develop Protective Antitumor Immune Responses with Appropriate Costimulation
Authors: Lustgarten Joseph , Dominguez Ana Lucia , Thoman Marilyn 
Published: April 2014

Abstract
There is a clear decrease in CD8+ T cell effector function with aging, a loss once thought to be intrinsic to the CD8+ T cells. Recent studies suggest, however, that this decline may be a consequence of altered stimulatory signals within the aged lymphoid microenvironment. In this study, we compared the immune responses of young and old mice against the BM-185 pre-B cell lymphoma expressing enhanced GFP (EGFP) as a surrogate tumor Ag. Young animals develop protective immune responses when immunized with BM-185-EGFP, but aged mice do not and ultimately succumb to the tumor. However, expression of CD80 (B7.1) on the BM-185-EGFP (BM-185-EGFP-CD80) results in rejection of the tumor by both young and old animals. Additionally, injection of BM-185-EGFP-CD80 cells in young mice promotes the development of long-lasting memory responses capable of rejecting BM-185 wild-type tumors. Aged animals similarly injected did not develop antitumor memory responses. Interestingly, old animals immunized with the BM-185-EGFP-CD80 cells plus injections of the agonist anti-OX40 mAb did develop long-lasting memory responses capable of rejecting the BM-185 wild-type tumors with the same vigor as the young animals. We show that old mice have the capacity to develop strong antitumor responses and protective memory responses as long as they are provided with efficient costimulation. These results have important implications for the development of vaccination strategies in the elderly, indicating that the aged T cell repertoire can be exploited for the induction of tumor immunity.
An IL-4Rα Allelic Variant, I50, Acts as a Gain-of-Function Variant Relative to V50 for Stat6, But Not Th2 Differentiation
Authors: Stephenson Linda , Johns Mary H. , Woodward Emily , Mora Ana L. , Boothby Mark 
Published: April 2014

Abstract
Signaling through the IL-4R α-chain (IL-4Rα) is crucial for the development of Th2 cells, central effectors in atopic disease. Alleles of the IL-4Rα have been identified that have been variably associated with increased incidence of allergic disease, but there is little direct evidence that any variant is sufficient to alter a target that determines allergic pathophysiology or susceptibility. Variants of IL-4Rα encoding isoleucine instead of valine at position 50 (I50 vs V50, respectively) can signal increased Stat6-dependent transcriptional activity, whether in an I50, Q551 or I50, R551 haplotype. Strikingly, signaling through these receptors did not increase the efficiency of Th2 development or the IL-4 mediated repression of Th1 development or a target gene, IL-18Rα. Further, IL-4-induced proliferation was similar for Th2 cells independent of the variant expressed. Together these findings indicate that IL-4Rα variants that exhibit gain-of-function with respect to Stat6 do not act directly through alterations in Th2/Th1 induction after Ag exposure. The data further suggest that for such variants, any mechanistic involvement is based on a role in cellular targets of Th2 cytokines.
A Profound Alteration of Blood TCRB Repertoire Allows Prediction of Cerebral Malaria
Authors: Collette Alexis , Bagot Sébastien , Ferrandiz Maria E. , Cazenave Pierre-André , Six Adrien , Pied Sylviane 
Published: April 2014

Abstract
Cerebral malaria (CM) is one of the severe complications of Plasmodium infection. In murine models of CM, Tαβ cells have been implicated in the neuropathogenesis. To obtain insights into the TCRB repertoire during CM, we used high throughput CDR3 spectratyping and set up new methods and software tools to analyze data. We compared PBL and spleen repertoires of mice infected with Plasmodium berghei ANKA that developed CM (CM+) or not (CM−) to evidence modifications of the TCRB repertoire associated with neuropathology. Using distinct statistical multivariate methods, the PBL repertoires of CM+ mice were found to be specifically altered. This alteration is partly due to recurrently expanded T cell clones. Strikingly, alteration of the PBL repertoire can be used to distinguish between CM+ and CM−. This study provides the first ex vivo demonstration of modifications of Tαβ cell compartment during CM. Finally, our original approach for deciphering lymphocyte repertoires can be transposed to various pathological conditions.
Superoxide Production at Phagosomal Cup/Phagosome through βI Protein Kinase C during FcγR-Mediated Phagocytosis in Microglia
Authors: Ueyama Takehiko , Lennartz Michelle R. , Noda Yukiko , Kobayashi Toshihiro , Shirai Yasuhito , Rikitake Kyoko , Yamasaki Tomoko , Hayashi Shigeto , Sakai Norio , Seguchi Harumichi , Sawada Makoto , Sumimoto Hideki , Saito Naoaki 
Published: April 2014

Abstract
Protein kinase C (PKC) plays a prominent role in immune signaling. To elucidate the signal transduction in a respiratory burst and isoform-specific function of PKC during FcγR-mediated phagocytosis, we used live, digital fluorescence imaging of mouse microglial cells expressing GFP-tagged molecules. βI PKC, εPKC, and diacylglycerol kinase (DGK) β dynamically and transiently accumulated around IgG-opsonized beads (BIgG). Moreover, the accumulation of p47phox, an essential cytosolic component of NADPH oxidase and a substrate for βI PKC, at the phagosomal cup/phagosome was apparent during BIgG ingestion. Superoxide (O2−) production was profoundly inhibited by Gö6976, a cPKC inhibitor, and dramatically increased by the DGK inhibitor, R59949. Ultrastructural analysis revealed that BIgG induced O2− production at the phagosome but not at the intracellular granules. We conclude that activation/accumulation of βI PKC is involved in O2− production, and that O2− production is primarily initiated at the phagosomal cup/phagosome. This study also suggests that DGKβ plays a prominent role in regulation of O2− production during FcγR-mediated phagocytosis.
Activation of CD8 T Cells by Mycobacterial Vaccination Protects against Pulmonary Tuberculosis in the Absence of CD4 T Cells
Authors: Wang Jun , Santosuosso Michael , Ngai Patricia , Zganiacz Anna , Xing Zhou 
Published: April 2014

Abstract
We have investigated whether both primary CD8 T cell activation and CD8 T cell-mediated protection from Mycobacterium tuberculosis challenge could occur in mycobacterial-vaccinated CD4 T cell-deficient (CD4KO) mice. Different from wild-type C57BL/6 mice, s.c. vaccination with bacillus Calmette-Guérin (BCG) in CD4KO mice failed to provide protection from secondary M. tuberculosis challenge at 3 wk postvaccination. However, similar to C57BL/6 mice, CD4KO mice were well protected from M. tuberculosis at weeks 6 and 12 postvaccination. This protection was mediated by CD8 T cells. The maintenance of protective effector/memory CD8 T cells in CD4KO mice did not require the continuous presence of live BCG vaccine. As in C57BL/6 mice, similar levels of primary activation of CD8 T cells in CD4KO mice occurred in the draining lymph nodes at 3 wk after BCG vaccination, but different from C57BL/6 mice, the distribution of these cells to the spleen and lungs of CD4KO mice was delayed, which coincided with delayed acquisition of protection in CD4KO mice. Our results suggest that both the primary and secondary activation of CD8 T cells is CD4 T cell independent and that the maintenance of these CD8 T cells is also independent of CD4 T cells and no longer requires the presence of live mycobacteria. However, the lack of CD4 T cells may result in delayed distribution of activated CD8 T cells from draining lymph nodes to distant organs and consequently a delayed acquisition of immune protection. Our findings hold implications in rational design of tuberculosis vaccination strategies for humans with impaired CD4 T cell function.
Novel and Promiscuous CTL Epitopes in Conserved Regions of Gag Targeted by Individuals with Early Subtype C HIV Type 1 Infection from Southern Africa
Authors: Masemola Agatha M. , Mashishi Tumelo N. , Khoury Greg , Bredell Helba , Paximadis Maria , Mathebula Tiyani , Barkhan Debra , Puren Adrian , Vardas Efthyia , Colvin Mark , Zijenah Lynn , Katzenstein David , Musonda Rosemary , Allen Susan , Kumwenda Newton , Taha Taha , Gray Glenda , McIntyre James , Karim Salim Abdool , Sheppard Haynes W. , Gray Clive M. ,   HIVNET 028 Study Team
Published: April 2014

AbstractCharacterization of optimal CTL epitopes in Gag can provide crucial information for evaluation of candidate vaccines in populations at the epicenter of the HIV-1 epidemic. We screened 38 individuals with recent subtype C HIV-1 infection using overlapping consensus C Gag peptides and hypothesized that unique HLA-restricting alleles in the southern African population would determine novel epitope identity. Seventy-four percent of individuals recognized at least one Gag peptide pool. Ten epitopic regions were identified across p17, p24, and p2p7p1p6, and greater than two-thirds of targeted regions were directed at: TGTEELRSLYNTVATLY (p17, 35%); GPKEPFRDYVDRFFKTLRAEQATQDV (p24, 19%); and RGGKLDKWEKIRLRPGGKKHYMLKHL (p17, 15%). After alignment of these epitopic regions with consensus M and a consensus subtype C sequence from the cohort, it was evident that the regions targeted were highly conserved. Fine epitope mapping revealed that five of nine identified optimal Gag epitopes were novel: HLVWASREL, LVWASRELERF, LYNTVATLY, PFRDYVDRFF, and TLRAEQATQD, and were restricted by unique HLA-Cw*08, HLA-A*30/B*57, HLA-A*29/B*44, and HLA-Cw*03 alleles, respectively. Notably, three of the mapped epitopes were restricted by more than one HLA allele. Although these epitopes were novel and restricted by unique HLA, they overlapped or were embedded within previously described CTL epitopes from subtype B HIV-1 infection. These data emphasize the promiscuous nature of epitope binding and support our hypothesis that HLA diversity between populations can shape fine epitope identity, but may not represent a constraint for universal recognition of Gag in highly conserved domains.
Lipoproteins, Not Lipopolysaccharide, Are the Key Mediators of the Proinflammatory Response Elicited by Heat-Killed Brucella abortus
Authors: Giambartolomei Guillermo H. , Zwerdling Astrid , Cassataro Juliana , Bruno Laura , Fossati Carlos A. , Philipp Mario T. 
Published: April 2014

Abstract
Inflammation is a hallmark of brucellosis. Although Brucella abortus, one of the disease’s etiologic agents, possesses cytokine-stimulatory properties, the mechanism by which this bacterium triggers a proinflammatory response is not known. We examined the mechanism whereby heat-killed B. abortus (HKBA), as well as its LPS, induces production of inflammatory cytokines in monocytes/macrophages. Polymyxin B, a specific inhibitor of LPS activity, did not inhibit the production of TNF-α- and IL-6-induced HKBA in the human monocytic cell line THP-1. HKBA induced the production of these cytokines in peritoneal macrophages of both C3H/HeJ and C3H/HeN mice, whereas B. abortus LPS only stimulated cells from C3H/HeN mice. Anti-TLR2 Ab, but not anti-TLR4 Ab, blocked HKBA-mediated TNF-α and IL-6 production in THP-1 cells. Because bacterial lipoproteins, a TLR2 ligand, have potent inherent stimulatory properties, we investigated the capacity of two B. abortus lipoproteins, outer membrane protein 19 (Omp19) and Omp16, to elicit a proinflammatory response. Lipidated (L)-Omp16 and L-Omp19, but not their unlipidated forms, induced the secretion of TNF-α, IL-6, IL-10, and IL-12 in a time- and dose-dependent fashion. Preincubation of THP-1 cells with anti-TLR2 Ab blocked L-Omp19-mediated TNF-α and IL-6 production. Together, these results entail a mechanism whereby B. abortus can stimulate cells from the innate immune system and induce cytokine-mediated inflammation in brucellosis. We submit that LPS is not the cause of inflammation in brucellosis; rather, lipoproteins of this organism trigger the production of proinflammatory cytokines, and TLR2 is involved in this process.
Stimulus-Dependent Requirement for Granulocyte-Macrophage Colony-Stimulating Factor in Inflammation
Authors: Cook Andrew D. , Braine Emma L. , Hamilton John A. 
Published: April 2014

AbstractData from several inflammation/autoimmunity models indicate that GM-CSF can be a key inflammatory mediator. Convenient models in readily accessible tissues are needed to enable the GM-CSF-dependent cellular responses to be elaborated. In this study, we show that, in contrast to the response to the commonly used i.p. irritant, thioglycolate medium, an Ag-specific methylated BSA-induced peritonitis in GM-CSF−/− mice was severely compromised. The reduced response in the latter peritonitis model was characterized by fewer neutrophils and macrophages, as well as by deficiencies in the properties of the remaining macrophages, namely size and granularity, phagocytosis, allogeneic T cell triggering, and proinflammatory cytokine production. B1 lymphocytes were more evident in the GM-CSF−/− Ag-specific exudates, indicating perhaps that GM-CSF can act on a common macrophage-B1 lymphocyte precursor in the inflamed peritoneum. We propose that these findings contribute to our understanding of how GM-CSF acts as a proinflammatory cytokine in many chronic inflammatory/autoimmune diseases. Of general significance, the findings also indicate that the nature of the stimulus is quite critical in determining whether a particular inflammatory mediator, such as GM-CSF, plays a role in an ensuing inflammatory reaction.
The Role of the Th2 CC Chemokine Ligand CCL17 in Pulmonary Fibrosis
Authors: Belperio John A. , Dy Maria , Murray Lynne , Burdick Marie D. , Xue Ying Y. , Strieter Robert M. , Keane Michael P. 
Published: April 2014

Abstract
Increasing evidence suggests that the development of pulmonary fibrosis is a Th2-mediated process. We hypothesized that the CC chemokines that are associated with a Th2 profile (CCL17 and CCL22) have an important role in the development of pulmonary fibrosis. We measured CCL17 and CCL22 during the pathogenesis of bleomycin-induced pulmonary fibrosis. We found that both CCL17 and CCL22 were significantly elevated through day 20 as compared with control mice. Peak expression of CCL22 preceded the peak levels of CCL17, as measured by real-time quantitative PCR. CCR4 is the receptor for CCL17 and CCL22 therefore, to further characterize the role of CCL17 and CCL22, we measured CCR4 mRNA in lung tissue of bleomycin-treated mice by real-time quantitative PCR. CCR4 was significantly elevated in bleomycin-treated mice as compared with control mice. Immunolocalization demonstrated that CCR4 was expressed predominantly on macrophages. Neutralization of CCL17, but not CCL22, led to a reduction in pulmonary fibrosis. Immunolocalization of bleomycin-treated lung tissue and human idiopathic pulmonary fibrosis tissue specimens showed that epithelial cells expressed CCL17. These findings demonstrate a central role for Th2 chemokines and the macrophage in the pathogenesis of pulmonary fibrosis and are further support for the role of a Th2 phenotype in the pathogenesis of pulmonary fibrosis.
Dual Mode of Action of a Human Anti-Epidermal Growth Factor Receptor Monoclonal Antibody for Cancer Therapy
Authors: Bleeker Wim K. , Lammerts van Bueren Jeroen J. , van Ojik Heidi H. , Gerritsen Arnout F. , Pluyter Marielle , Houtkamp Mischa , Halk Ed , Goldstein Joel , Schuurman Janine , van Dijk Marc A. , van de Winkel Jan G. J. , Parren Paul W. H. I. 
Published: April 2014

Abstract
Epidermal growth factor receptor (EGF-R) overexpression is common in a large number of solid tumors and represents a negative prognostic indicator. Overexpression of EGF-R is strongly tumor associated, and this tyrosine kinase type receptor is considered an attractive target for Ab therapy. In this study, we describe the evaluation of mAb 2F8, a high avidity human mAb (IgG1κ) directed against EGF-R, developed using human Ig transgenic mice. mAb 2F8 effectively blocked binding of EGF and TGF-α to the EGF-R. At saturating concentrations, 2F8 completely blocked EGF-R signaling and inhibited the in vitro proliferation of EGF-R-overexpressing A431 cells. At much lower concentrations, associated with low receptor occupancy, 2F8 induced efficient Ab-dependent cell-mediated cytotoxicity (ADCC) in vitro. In vivo studies showed potent antitumor effects in models with A431 tumor xenografts in athymic mice. Ex vivo analysis of the EGF-R status in tumor xenografts in 2F8-treated mice revealed that there are two therapeutic mechanisms. First, blocking of EGF-R signaling, which is most effective at complete receptor saturation and therefore requires a relatively high Ab dose. Second, at very low 2F8 receptor occupancy, we observed potent antitumor effects in mice, which are likely based on the engagement of immune effector mechanisms, in particular ADCC. Taken together, our findings indicate that ADCC represents an important effector mechanism of this Ab, which is effective at relatively low dose.
Induction of Immunological Tolerance/Hyporesponsiveness in Baboons with a Nondepleting CD4 Antibody
Authors: Winsor-Hines Dawn , Merrill Christopher , O’Mahony Mark , Rao Patricia E. , Cobbold Stephen P. , Waldmann Herman , Ringler Douglas J. , Ponath Paul D. 
Published: April 2014

Abstract
Tolerance induction with anti-CD4 Abs is well established in rodent transplant and autoimmune disease models, but has yet to be demonstrated in non-human primates or in clinical studies. In retrospect, failure of anti-CD4 Abs to induce tolerance in primates may be technical, a consequence of insufficient dosing and Ab properties influencing immunogenicity and cell depletion. To circumvent these possible limitations, we constructed a novel anti-CD4 mAb, TRX1, humanized to reduce immunogenicity and Fc-modified to prevent cell depletion. Using equine immune globulin (equine Ig) as a model Ag, we examined the tolerance-inducing capacity of TRX1 in baboons. During the induction phase, TRX1 inhibited the humoral response to equine Ig in a dose-dependent manner, with complete suppression of response at the highest dose tested (40 mg/kg). Upon challenge, anti-equine Ig responses were generated in baboons treated with 1 and 10 mg/kg doses of TRX1 and in control animals. In higher dosing cohorts (20 and 40 mg/kg), however, the immune response to equine Ig was modulated in seven of nine animals, including complete unresponsiveness to Ag challenges in two animals. Five of nine were hyporesponsive to equine Ig, generating titers 50- to 250-fold lower than control groups. Repeated challenge resulted in titers falling to baseline or near baseline, with two of five hyporesponsive animals becoming unresponsive to Ag. All animals responded to neoantigen immunization, indicating that the modified response to equine Ig was Ag specific. These studies demonstrate that anti-CD4 Ab-mediated, Ag-specific tolerance can be achieved in baboons without long term immune suppression.
A Critical Role for FcγRIIB in the Induction of Rheumatoid Factors
Authors: Moll Thomas , Nitschke Lars , Carroll Michael , Ravetch Jeffrey V. , Izui Shozo 
Published: April 2014

AbstractRheumatoid factors (RF) are autoantibodies with specificity for the Fc portion of IgG, and IgG-containing immune complexes are likely to be the major source of RF autoantigens. Therefore, the activation of RF-producing B cells could be controlled specifically through recognition of IgG immune complexes by the low-affinity IgG FcR, FcγRIIB, a potent negative regulator of the BCR. To test this possibility, we determined the development of RF in C57BL/6 (B6) mice lacking FcγRIIB, in relation to the H2 haplotype, complement C3, and the Y-linked autoimmune acceleration (Yaa) mutation. FcγRIIB-null B6 mice displayed substantial anti-IgG2a RF activities in their sera, in addition to anti-DNA autoantibodies. Their RF and anti-DNA responses were linked to the H2b haplotype, but were suppressed almost completely by the H2d haplotype. Strikingly, the absence of C3 failed to modulate RF production, but strongly inhibited anti-DNA production. Furthermore, we observed that partial FcγRIIB deficiency (i.e., heterozygous level of FcγRIIB expression) was sufficient to induce the production of RF and anti-DNA autoantibodies in the presence of the Yaa mutation. In contrast to FcγRIIB, the deficiency in another BCR negative regulator, CD22, was unable to promote RF and anti-DNA autoimmune responses in B6 mice. Our results indicate that RF autoimmune responses are critically controlled by FcγRIIB, together with the H2b and Yaa gene, while C3 regulates positively and specifically anti-DNA, but not RF autoimmune responses.
Secreted Immunomodulatory Viral Proteins as Novel Biotherapeutics
Authors: Lucas Alexandra , McFadden Grant 
Published: April 2014

AbstractMany viruses have learned to evade or subvert the host antiviral immune responses by encoding and expressing immunomodulatory proteins that protect the virus from attack by elements of the innate and acquired immune systems. Some of these viral anti-immune regulators are expressed as secreted proteins that engage specific host immune targets in the extracellular environment, where they exhibit potent anti-immune properties. We review here viral immunomodulatory proteins that have been tested as anti-inflammatory reagents in animal models of disease caused by excessive inflammation or hyperactivated immune pathways. The potential for such viral molecules for the development of novel drugs to treat immune-based or inflammatory disorders is discussed.