bluuebunny/crossref_metadata_2025_split huggingface dataset:
CD22 Ligand Binding Regulates Normal and Malignant B Lymphocyte Survival In Vivo
Authors: Haas Karen M. , Sen Suman , Sanford Isaac G. , Miller Ann S. , Poe Jonathan C. , Tedder Thomas F. 
Published: April 2014

Abstract
The CD22 extracellular domain regulates B lymphocyte function by interacting with α2,6-linked sialic acid-bearing ligands. To understand how CD22 ligand interactions affect B cell function in vivo, mouse anti-mouse CD22 mAbs were generated that inhibit CD22 ligand binding to varying degrees. Remarkably, mAbs which blocked CD22 ligand binding accelerated mature B cell turnover by 2- to 4-fold in blood, spleen, and lymph nodes. CD22 ligand-blocking mAbs also inhibited the survival of adoptively transferred normal (73–88%) and malignant (90%) B cells in vivo. Moreover, mAbs that bound CD22 ligand binding domains induced significant CD22 internalization, depleted marginal zone B cells (82–99%), and reduced mature recirculating B cell numbers by 75–85%. The CD22 mAb effects were independent of complement and FcRs, and the CD22 mAbs had minimal effects in CD22AA mice that express mutated CD22 that is not capable of ligand binding. These data demonstrate that inhibition of CD22 ligand binding can disrupt normal and malignant B cell survival in vivo and suggest a novel mechanism of action for therapeutics targeting CD22 ligand binding domains.
Early Immunization Induces Persistent Tumor-Infiltrating CD8+ T Cells against an Immunodominant Epitope and Promotes Lifelong Control of Pancreatic Tumor Progression in SV40 Tumor Antigen Transgenic Mice
Authors: Otahal Pavel , Schell Todd D. , Hutchinson Sandra C. , Knowles Barbara B. , Tevethia Satvir S. 
Published: April 2014

AbstractThe ability to recruit the host’s CD8+ T lymphocytes (TCD8) against cancer is often limited by the development of peripheral tolerance toward the dominant tumor-associated Ags. Because multiple epitopes derived from a given tumor Ag (T Ag) can be targeted by TCD8, vaccine approaches should be directed toward those TCD8 that are more likely to survive under conditions of persistent Ag expression. In this study, we investigated the effect of peripheral tolerance on the endogenous TCD8 response toward two epitopes, designated epitopes I and IV, from the SV40 large T Ag. Using rat insulin promoter (RIP) 1-Tag4 transgenic mice that express T Ag from the RIP and develop pancreatic insulinomas, we demonstrate that epitope IV- but not epitope I-specific TCD8 are maintained long term in tumor-bearing RIP1-Tag4 mice. Even large numbers of TCR-transgenic T cells specific for epitope I were rapidly eliminated from RIP1-Tag4 mice after adoptive transfer and recognition of the endogenous T Ag. Importantly, immunization of RIP1-Tag4 mice at 5 wk of age against epitope IV resulted in complete protection from tumor progression over a 2-year period despite continued expression of T Ag in the pancreas. This extensive control of tumor progression was associated with the persistence of functional epitope IV-specific TCD8 within the pancreas for the lifetime of the mice without the development of diabetes. This study indicates that an equilibrium is reached in which immune surveillance for spontaneous cancer can be achieved for the lifespan of the host while maintaining normal organ function.
MHC Class I-Like MILL Molecules Are β2-Microglobulin-Associated, GPI-Anchored Glycoproteins That Do Not Require TAP for Cell Surface Expression
Authors: Kajikawa Mizuho , Baba Tomohisa , Tomaru Utano , Watanabe Yutaka , Koganei Satoru , Tsuji-Kawahara Sachiyo , Matsumoto Naoki , Yamamoto Kazuo , Miyazawa Masaaki , Maenaka Katsumi , Ishizu Akihiro , Kasahara Masanori 
Published: April 2014

Abstract
MILL (MHC class I-like located near the leukocyte receptor complex) is a family of MHC class I-like molecules encoded outside the MHC, which displays the highest sequence similarity to human MICA/B molecules among known class I molecules. In the present study, we show that the two members of the mouse MILL family, MILL1 and MILL2, are GPI-anchored glycoproteins associated with β2-microglobulin (β2m) and that cell surface expression of MILL1 or MILL2 does not require functional TAP molecules. MILL1 and MILL2 molecules expressed in bacteria could be refolded in the presence of β2m, without adding any peptides. Hence, neither MILL1 nor MILL2 is likely to be involved in the presentation of peptides. Immunohistochemical analysis revealed that MILL1 is expressed in a subpopulation of thymic medullary epithelial cells and a restricted region of inner root sheaths in hair follicles. The present study provides additional evidence that MILL is a class I family distinct from MICA/B.
Mutational Analysis of the Mechanism of Negative Regulation by Src Homology 2 Domain-Containing Protein Tyrosine Phosphatase Substrate-1 of Phagocytosis in Macrophages
Authors: Ikeda Hiroshi , Okazawa Hideki , Ohnishi Hiroshi , Murata Yoji , Oldenborg Per-Arne , Matozaki Takashi 
Published: April 2014

AbstractSrc homology 2 domain-containing protein tyrosine phosphatase substrate-1 (SHPS-1) is a transmembrane protein predominantly expressed in macrophages. The binding of CD47 on RBCs to SHPS-1 on macrophages is implicated in inhibition of phagocytosis of the former cells by the latter. We have now shown that forced expression in mouse RAW264.7 macrophages of a mutant version (SHPS-1-4F) of mouse SHPS-1, in which four tyrosine phosphorylation sites are replaced by phenylalanine, markedly promoted FcγR-mediated phagocytosis of mouse RBCs or SRBCs. Forced expression of another mutant form (SHPS-1-ΔCyto) of mouse SHPS-1, which lacks most of the cytoplasmic region, did not promote such phagocytosis. Similarly, forced expression of a rat version of SHPS-1-4F, but not that of rat wild-type SHPS-1 or SHPS-1-ΔCyto, in RAW264.7 cells enhanced FcγR-mediated phagocytosis of RBCs. Tyrosine phosphorylation of endogenous SHPS-1 as well as its association with Src homology 2 domain-containing protein tyrosine phosphatase-1 were not markedly inhibited by expression of SHPS-1-4F. Furthermore, the attachment of IgG-opsonized RBCs to RAW264.7 cells was markedly increased by expression of SHPS-1-4F, and this effect did not appear to be mediated by the interaction between CD47 and SHPS-1. These data suggest that inhibition by SHPS-1 of phagocytosis in macrophages is mediated, at least in part, in a manner independent of the transinteraction between CD47 and SHPS-1. In addition, the cytoplasmic region as well as tyrosine phosphorylation sites in this region of SHPS-1 appear indispensable for this inhibitory action of SHPS-1. Moreover, SHPS-1 may regulate the attachment of RBCs to macrophages by an as yet unidentified mechanism.
HLA-B44 Polymorphisms at Position 116 of the Heavy Chain Influence TAP Complex Binding via an Effect on Peptide Occupancy
Authors: Thammavongsa Vilasack , Raghuraman Gayatri , Filzen Tracy M. , Collins Kathleen L. , Raghavan Malini 
Published: April 2014

Abstract
A single residue polymorphism distinguishes HLA-B*4402(D116) from HLA-B*4405(Y116), which was suggested to allow HLA-B*4405 to acquire peptides without binding to tapasin-TAP complexes. We show that HLA-B*4405 is not inherently unable to associate with tapasin-TAP complexes. Under conditions of peptide deficiency, both allotypes bound efficiently to TAP and tapasin, and furthermore, random nonamer peptides conferred higher thermostability to HLA-B*4405 than to HLA-B*4402. Correspondingly, under conditions of peptide sufficiency, more rapid peptide-loading, dissociation from TAP complexes, and endoplasmic reticulum exit were observed for HLA-B*4405, whereas HLA-B*4402 showed greater endoplasmic reticulum retention and enhanced tapasin-TAP binding. Together, these studies suggest that position 116 HLA polymorphisms influence peptide occupancy, which in turn determines binding to tapasin and TAP. Relative to HLA-B*4405, inefficient peptide loading of HLA-B*4402 is likely to underlie its stronger tapasin dependence for cell surface expression and thermostability, and its enhanced susceptibility to pathogen interference strategies.
Not Lipoteichoic Acid but Lipoproteins Appear to Be the Dominant Immunobiologically Active Compounds in Staphylococcus aureus
Authors: Hashimoto Masahito , Tawaratsumida Kazuki , Kariya Hiroyuki , Kiyohara Ai , Suda Yasuo , Krikae Fumiko , Kirikae Teruo , Götz Friedrich 
Published: April 2014

Abstract
Lipoteichoic acid (LTA) derived from Staphylococcus aureus is reported to be a ligand of TLR2. However, we previously demonstrated that LTA fraction prepared from bacterial cells contains lipoproteins, which activate cells via TLR2. In this study, we investigated the immunobiological activity of LTA fraction obtained from S. aureus wild-type strain, lipoprotein diacylglycerol transferase deletion (Δlgt) mutant, which lacks palmitate-labeled lipoproteins, and its complemented strain and evaluated the activity of LTA molecule. LTA fraction was prepared by butanol extraction of the bacteria followed by hydrophobic interaction chromatography. Although all LTA fractions activated cells through TLR2, the LTA from Δlgt mutant was 100-fold less potent than those of wild-type and complemented strains. However, no significant structural difference in LTA was observed in NMR spectra. Further, alanylation of LTA molecule showed no effect in immunobiological activity. These results showed that not LTA molecule but lipoproteins are dominant immunobiologically active TLR2 ligand in S. aureus.
Molecular Analysis of NTB-A Signaling: A Role for EAT-2 in NTB-A-Mediated Activation of Human NK Cells
Authors: Eissmann Philipp , Watzl Carsten 
Published: April 2014

Abstract
Engagement of NTB-A on human NK cells by homophilic interaction with NTB-A-expressing target cells can trigger NK cell cytotoxicity, cytokine production, and proliferation. To better understand how NTB-A can activate NK cells, we analyzed the molecular mechanisms of NTB-A signaling. We show that NTB-A is tyrosine phosphorylated in unstimulated human NK cells and associates with SLAM-associated protein (SAP) and EAT-2. This phosphorylation of NTB-A is mediated by Src family kinases and is most likely a result of the homophilic interaction of NTB-A among neighboring NK cells. Stimulation of NK cells by NTB-A-positive targets results in increased NTB-A phosphorylation. The cytoplasmic tail of NTB-A contains three tyrosines, two of which are embedded within an immunoreceptor tyrosine-based switch motif. We generated a NTB-A-negative NK cell line, in which we expressed different mutants of NTB-A. Functional studies showed that the second tyrosine is sufficient and essential for NTB-A-mediated cytotoxicity. EAT-2, but not SAP, is recruited to this second tyrosine, indicating that SAP may be dispensable for this NTB-A function. To further investigate this, we silenced SAP expression in NK cell lines. Functional analysis of these cells showed that NTB-A can mediate NK cell cytotoxicity in the absence of SAP, probably via EAT-2. In contrast, NTB-A-mediated IFN-γ production was greatly reduced in the absence of SAP, demonstrating that cytokine production and cytotoxicity are differentially dependent on SAP and possibly EAT-2.
Murine Vβ3+ and Vβ7+ T Cell Subsets Are Specific Targets for the HERV-K18 Env Superantigen
Authors: Tai Albert K. , Lin Miao , Chang Francesca , Chen Gang , Hsiao Francis , Sutkowski Natalie , Huber Brigitte T. 
Published: April 2014

Abstract
Superantigens are a class of proteins that are derived from microorganisms and have the unique characteristic of stimulating T cells in a TCR Vβ-specific manner, causing massive T cell proliferation and immune deregulation. For this reason, superantigens have been implicated in the development of multiple diseases. We have previously identified and cloned an EBV-associated superantigen, human endogenous retrovirus (HERV)-K18 envelope protein (Env). This superantigen is transactivated upon IFN-α treatment and EBV infection and stimulates human Vβ13+ T cells. Due to the limited scope of work that can be conducted with human samples and the complexity of HERVs in general, we set out to study the physiological effects of HERV-K18 Env in a murine model. In this report, we demonstrate the superantigen activity of HERV-K18 Env in mice and describe the generation of HERV-K18 transgenics, using a bacterial artificial chromosome as transgenes that allow the faithful reproduction of the expression pattern of this human provirus. From our in vitro and in vivo results we conclude that HERV-K18 Env stimulates Vβ3+ and Vβ7+ T cells in mice. The definition of the murine Vβ specificity and the establishment of a transgenic model will permit the investigation of the role of this superantigen in the life cycle of EBV and its implicated diseases.
Type I IFNs Stimulate Nitric Oxide Production and Resistance to Trypanosoma cruzi Infection
Authors: Costa Vlaudia M. A. , Torres Karen C. L. , Mendonça Ronaldo Z. , Gresser Ion , Gollob Kenneth J. , Abrahamsohn Ises A. 
Published: April 2014

Abstract
The participation of type I IFNs (IFN-I) in NO production and resistance to Trypanosoma cruzi infection was investigated. Adherent cells obtained from the peritoneal cavity of mice infected by the i.p. route produced NO and IFN-I. Synthesis of NO by these cells was partially inhibited by treatment with anti-IFN-αβ or anti-TNF-α Abs. Compared with susceptible BALB/c mice, peritoneal cells from parasite-infected resistant C57BL/6 mice produced more NO (2-fold), IFN-I (10-fold), and TNF-α (3.5-fold). Later in the infection, IFN-I levels measured in spleen cell (SC) cultures from 8-day infected mice were greater in C57BL/6 than in infected BALB/c mice, and treatment of the cultures with anti-IFN-αβ Ab reduced NO production. IFN-γ or IL-10 production by SCs was not different between the two mouse strains; IL-4 was not detectable. Treatment of C57BL/6 mice with IFN-I reduced parasitemia levels in the acute phase of infection. Mice deprived of the IFN-αβR gene developed 3-fold higher parasitemia levels in the acute phase in comparison with control 129Sv mice. Production of NO by peritoneal macrophages and SCs was reduced in mice that lacked signaling by IFN-αβ, whereas parasitism of macrophages was heavier than in control wild-type mice. We conclude that IFN-I costimulate NO synthesis early in T. cruzi infection, which contributes to a better control of the parasitemia in resistant mice.
Exhaustion of Type I Interferon Response following an Acute Viral Infection
Authors: Alsharifi Mohammed , Regner Matthias , Blanden Robert , Lobigs Mario , Lee Eva , Koskinen Aulikki , Müllbacher Arno 
Published: April 2014

AbstractViral infections often cause a period of heightened susceptibility to a secondary infection but the cause of this phenomenon is unknown. We found that a primary viral infection in mice rapidly triggers an IFN-I-dependent partial activation state in the majority of B and T lymphocytes, which reverts to a resting phenotype within 5 days. When a secondary infection with an unrelated virus occurred 5 to 9 days after the primary infection, no recurrence of marked activation of lymphocytes was observed. This was not due to an inherent inability of the previously activated cells to undergo renewed partial activation, because they responded when challenged with virus after transfer into “naive” recipients. Instead, the failure to respond optimally resided in the original host’s incapacity to mount an IFN-I response to the secondary infection during this time period. Thus, transient immunosuppression through exhaustion of IFN-I production during an acute viral infection creates a time period of enhanced susceptibility to secondary infection.
The Roles of Bacteria and TLR4 in Rat and Murine Models of Necrotizing Enterocolitis
Authors: Jilling Tamas , Simon Dyan , Lu Jing , Meng Fan Jing , Li Dan , Schy Robert , Thomson Richard B. , Soliman Antoine , Arditi Moshe , Caplan Michael S. 
Published: April 2014

Abstract
Bacteria are thought to contribute to the pathogenesis of necrotizing enterocolitis (NEC), but it is unknown whether their interaction with the epithelium can participate in the initiation of mucosal injury or they can act only following translocation across a damaged intestinal barrier. Our aims were to determine whether bacteria and intestinal epithelial TLR4 play roles in a well-established neonatal rat model and a novel neonatal murine model of NEC. Neonatal rats, C57BL/6J, C3HeB/FeJ (TLR4 wild type), and C3H/HeJ (TLR4 mutant) mice were delivered by Cesarean section and were subjected to formula feeding and cold asphyxia stress or were delivered naturally and were mother-fed. NEC incidence was evaluated by histological scoring, and gene expression was quantified using quantitative real-time PCR from cDNA generated from intestinal total RNA or from RNA obtained by laser capture microdissection. Spontaneous feeding catheter colonization or supplementation of cultured bacterial isolates to formula increased the incidence of experimental NEC. During the first 72 h of life, i.e., the time frame of NEC development in this model, intestinal TLR4 mRNA gradually decreases in mother-fed but increases in formula feeding and cold asphyxia stress, correlating with induced inducible NO synthase. TLR4, inducible NO synthase, and inflammatory cytokine induction occurred in the intestinal epithelium but not in the submucosa. NEC incidence was diminished in C3H/HeJ mice, compared with C3HeB/FeJ mice. In summary, bacteria and TLR4 play significant roles in experimental NEC, likely via an interaction of intraluminal bacteria and aberrantly overexpressed TLR4 in enterocytes.
EBV Can Protect Latently Infected B Cell Lymphomas from Death Receptor-Induced Apoptosis
Authors: Snow Andrew L. , Lambert Stacie L. , Natkunam Yasodha , Esquivel Carlos O. , Krams Sheri M. , Martinez Olivia M. 
Published: April 2014

Abstract
The relationship between EBV infection and sensitivity to death receptor (DR)-induced apoptosis is poorly understood. Using EBV− and EBV+ BJAB cells, we provide the first evidence that EBV can protect latently infected B cell lymphomas from apoptosis triggered through Fas or TRAIL receptors. Caspase 8 activation was impaired and cellular FLIP recruitment was enriched in death-inducing signaling complexes formed in EBV-infected BJAB cells relative to parent BJAB cells. Furthermore, latent membrane protein 1 expression alone could reduce caspase activation and confer partial resistance to DR apoptosis in BJAB cells. This protective effect was dependent on C-terminal activating region 2-driven NF-κB activation, which in turn up-regulated cellular FLIP expression in latent membrane protein 1+ BJAB cells. Thus, the ability of latent EBV to block DR apoptosis may help to ensure the survival of host cells during B cell differentiation, and contribute to the development of B cell lymphomas, especially in immunocompromised individuals.
Characterization of theHistoplasma capsulatum-Induced Granuloma
Authors: Heninger Erika , Hogan Laura H. , Karman Jozsef , Macvilay Sinarack , Hill Bjork , Woods Jon P. , Sandor Matyas 
Published: April 2014

AbstractRising rates of Histoplasma capsulatum infection are an emerging problem among the rapidly growing population of immune-compromised individuals. Although there is a growing understanding of systemic immunity against Histoplasma, little is known about the local granulomatous response, which is an important component in the control of infection. The focus of this article is the characterization of Histoplasma-induced granulomas. Five days after i.p. infection, infected macrophage appear in the liver and lung; however, no granulomas are apparent. Two days later, well-formed sarcoid granulomas are abundant in the lung and liver of infected mice, which contain all visible Histoplasma. Granulomas are dominated by macrophage and lymphocytes. Most of the Histoplasma and most of the apoptotic cells are found in the center of the lesions. We isolated liver granulomas at multiple time points after infection and analyzed the cellular composition, TCR gene usage, and cytokine production of granuloma-infiltrating cells. The lesions contain both CD4+ and CD8+ T cell subsets, and T cells are the primary source of IFN-γ and IL-17. The main source of local TNF-α is macrophage. Chemokines are produced by both infiltrating macrophage and lymphocytes. Dendritic cells are present in granulomas; however, T cell expansion seems to occur systemically because TCR usage is very heterogeneous even at the level of individual lesions. This study is the first direct examination of host cellular responses in the Histoplasma-induced granuloma representing the specific interface between host and pathogen. Our studies will allow further analysis of key elements of host Histoplasma interactions at the site of chronic infection.
Immune Interactions with CD4+ T Cells Promote the Development of Functional Osteoclasts from Murine CD11c+ Dendritic Cells
Authors: Alnaeeli Mawadda , Penninger Josef M. , Teng Yen-Tung Andy 
Published: April 2014

Abstract
Dendritic cells (DC) are innate immune effectors and are critically involved in regulating T cell immunity. Osteoclasts (OC) are bone-resorbing cells derived from the monocyte/macrophage lineage in response to receptor activator of NF-κB ligand (RANKL). DC and T cells form aggregates in the inflammatory infiltrates at active disease sites in human and in experimental rheumatoid arthritis and periodontitis. We investigated whether DC interactions with T cells in the bone environment can support the development of functional OC. In the present study, we demonstrate that upon proper activation by microbial or protein Ags (namely Actinobacillus actinomycetemcomitans, bovine insulin, and outer membrane protein-1) and during immune interactions with CD4+ T cells in vitro, murine BM-derived and splenic CD11c+ DC (CD11b−F4/80−Ly-6C−CD31−) develop into TRAP+CT-R+cathepsin-k+ functional OC in a RANKL/RANK-dependent manner. Rescue and blocking experiments using CD11c+ DC derived from Csf-1−/−op/op mice show that M-CSF is required “before” developing such osteoclastogenic potential upstream of RANKL/RANK signaling, suggesting that immature CD11c+ DC can indeed act like OC precursors. In addition, these CD11c+ DC-derived OC are capable of inducing bone loss after adoptive transfer in vivo. These data suggest a direct contribution of DC during immune interactions with CD4+ T cells to inflammation-induced osteoclastogenesis. Therefore, our findings not only provide further evidence for DC plasticity, but also extend the current paradigm of osteoimmunology.
Specific Contribution of p19ARF to Nitric Oxide-Dependent Apoptosis
Authors: Zeini Miriam , Través Paqui G. , López-Fontal Raquel , Pantoja Cristina , Matheu Ander , Serrano Manuel , Boscá Lisardo , Hortelano Sonsoles 
Published: April 2014

Abstract
NO is an important bioactive molecule involved in a variety of physio- and pathological processes, including apoptosis induction. The proapoptotic activity of NO involves the rise in the tumor suppressor p53 and the accumulation and targeting of proapoptotic members of the Bcl-2 family, in particular Bax and the release of cytochrome c from the mitochondria. However, the exact mechanism by which NO induces p53 activation has not been fully elucidated. In this study, we describe that NO induces p19ARF through a transcriptional mechanism. This up-regulation of p19ARF activates p53, leading to apoptosis. The importance of p19ARF on NO-dependent apoptosis was revealed by the finding that various cell types from alternate reading frame-knockout mice exhibit a diminished response to NO-mediated apoptosis when compared with normal mice. Moreover, the biological relevance of alternative reading frame to p53 apoptosis was confirmed in in vivo models of apoptosis. Together, these results demonstrate that NO-dependent apoptosis requires, in part, the activation of p19ARF.