bluuebunny/crossref_metadata_2025_split huggingface dataset:
HSP110-HER2/neu Chaperone Complex Vaccine Induces Protective Immunity Against Spontaneous Mammary Tumors in HER-2/neu Transgenic Mice
Authors: Manjili Masoud H. , Wang Xiang-Yang , Chen Xing , Martin Thomas , Repasky Elizabeth A. , Henderson Robert , Subjeck John R. 
Published: April 2014

Abstract
Heat shock proteins (HSPs) are shown to be strong immunoadjuvants, eliciting both innate and adaptive immune responses against cancers. HSP110 is related in sequence to HSP70 and is ∼4-fold more efficient in binding to and stabilizing denatured protein substrates compared with HSP70. In the present study we evaluated the ability of a heat shock complex of HSP110 with the intracellular domain (ICD) of human HER-2/neu to elicit effective antitumor immune responses and to inhibit spontaneous mammary tumors in FVB-neu (FVBN202) transgenic mice. The HSP110-ICD complex was capable of breaking tolerance against the rat neu protein and inhibiting spontaneous mammary tumor development. This vaccine induced ICD-specific IFN-γ and IL-4 production. Depletion studies revealed that CD8+ T cells were involved in protection against challenge with mouse mammary tumors, whereas CD4+ T cells revealed partial protection. Increased IgG2a Ab titer in the sera of tumor-free animals after vaccination and elevated CD4+ CD25+ regulatory T cells in the PBL of tumor-bearing animals suggested that IFN-γ-producing Th1 cells may be responsible for partial protection of CD4+ T cells against the mammary tumor challenge, whereas CD4+CD25+ regulatory T cells (Th2 cells) may suppress the antitumor immune responses. Together, these results suggest that HSP110-ICD complex can elicit effective IFN-γ-producing T cells against spontaneous mammary tumors and that up-regulation of CD4+ CD25+ regulatory T cells may prevent complete eradication of the tumor following immunotherapy.
Functional Segregation of the TCR and Antigen-MHC Complexes on the Surface of CTL
Authors: Mekala Divya J. , Geiger Terrence L. 
Published: April 2014

AbstractAs CTL adhere to and lyze their targets, they extract cognate Ag-MHC and represent this on their own cell surface. Whether such self-presented cognate Ag stimulate the TCR of a CTL is uncertain. To analyze this, we examined TCR capping in response to self-presented Ag. We found that OVA peptide-specific OT-1 CTL that were pulsed with cognate peptide Ag did not cap their TCR, implying that the autologously presented MHC-Ag complex does not normally stimulate the TCR. However, this functional separation of the TCR and its ligand on the cell surface was not absolute. Treatment of Ag-pulsed OT-1 CTL with agents that alter cell surface charge, including trypsin, papain, tunicamycin, neuraminidase, and polybrene, allowed Ag-specific TCR capping. The TCR capped together with the restricting MHC molecule on the surface of the cell, implying an interaction between the TCR and cell-associated Ag. Further, the treated CTL underwent a time- and dose-dependent suicidal death that was both Fas- and perforin-dependent. Therefore, our results indicate that the association of the TCR with its MHC-peptide ligand on the surface of a CTL is normally proscribed by biophysical properties of the plasma membrane. Overcoming this restriction allows TCR stimulation and induces CTL effector functions and cell suicide.
T Cell-Specific Disruption of Arylhydrocarbon Receptor Nuclear Translocator (Arnt) Gene Causes Resistance to 2,3,7,8-Tetrachlorodibenzo-p-dioxin-Induced Thymic Involution
Authors: Tomita Shuhei , Jiang Hou-Bo , Ueno Tomoo , Takagi Satoshi , Tohi Keiko , Maekawa Shin-ichi , Miyatake Akira , Furukawa Aizo , Gonzalez Frank J. , Takeda Junji , Ichikawa Yoshiyuki , Takahama Yousuke 
Published: April 2014

AbstractThe arylhydrocarbon receptor nuclear translocator (ARNT) is a member of the basic helix-loop-helix, PER-ARNT-SIM family of heterodimeric transcription factors, and serves as a dimerization partner for arylhydrocarbon receptor (AHR) and hypoxia-inducible factor-1α. To assess the function of ARNT in T cells, we disrupted the Arnt gene specifically in T cells of mice by conditional gene targeting using T cell-specific p56lck-Cre (Lck-Cre) transgenic Arnt-floxed mice. Thus generated, T cell-specific Arnt-disrupted mice (Lck-Cre;Arntflox/Δ transgenic mice) exhibited complete loss of the expression of ARNT protein only in T cells, and were viable and appeared normal. The Arnt-disrupted T cells in the thymus were phenotypically and histologically normal. The Arnt-deficient T cells in the spleen were capable of responding to TCR stimulation in vitro. However, unlike normal mice in which exposure to the environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an AHR ligand, resulted in thymic involution, the thymus of Lck-Cre;Arntflox/Δ mice were resistant to TCDD treatment in vivo. In contrast, benzo(a)pyrene, another AHR ligand, still caused thymic involution in Lck-Cre;Arntflox/Δ mice. Finally, fetal thymus organ culture using Lck-Cre;Arntflox/Δ and K5-Cre;Arntflox/Δ (epithelial cell-specific Arnt-disrupted mice) showed that thymocytes rather than thymic epithelial cells are predominantly responsible for TCDD-induced thymic atrophy. Our results indicate that ARNT in T lineage cells is essential for TCDD-mediated thymic involution.
Enhanced Effector and Memory CTL Responses Generated by Incorporation of Receptor Activator of NF-κB (RANK)/RANK Ligand Costimulatory Molecules into Dendritic Cell Immunogens Expressing a Human Tumor-Specific Antigen
Authors: Wiethe Carsten , Dittmar Kurt , Doan Tracy , Lindenmaier Werner , Tindle Robert 
Published: April 2014

AbstractThe outcome of dendritic cell (DC) presentation of Ag to T cells via the TCR/MHC synapse is determined by second signaling through CD80/86 and, importantly, by ligation of costimulatory ligands and receptors located at the DC and T cell surfaces. Downstream signaling triggered by costimulatory molecule ligation results in reciprocal DC and T cell activation and survival, which predisposes to enhanced T cell-mediated immune responses. In this study, we used adenoviral vectors to express a model tumor Ag (the E7 oncoprotein of human papillomavirus 16) with or without coexpression of receptor activator of NF-κB (RANK)/RANK ligand (RANKL) or CD40/CD40L costimulatory molecules, and used these transgenic DCs to immunize mice for the generation of E7-directed CD8+ T cell responses. We show that coexpression of RANK/RANKL, but not CD40/CD40L, in E7-expressing DCs augmented E7-specific IFN-γ-secreting effector and memory T cells and E7-specific CTLs. These responses were also augmented by coexpression of T cell costimulatory molecules (RANKL and CD40L) or DC costimulatory molecules (RANK and CD40) in the E7-expressing DC immunogens. Augmentation of CTL responses correlated with up-regulation of CD80 and CD86 expression in DCs transduced with costimulatory molecules, suggesting a mechanism for enhanced T cell activation/survival. These results have generic implications for improved tumor Ag-expressing DC vaccines, and specific implications for a DC-based vaccine approach for human papillomavirus 16-associated cervical carcinoma.
Lysosomal Localization of Murine CD1d Mediated by AP-3 Is Necessary for NK T Cell Development
Authors: Cernadas Manuela , Sugita Masahiko , van der Wel Nicole , Cao Xiaochun , Gumperz Jenny E. , Maltsev Sergei , Besra Gurdyal S. , Behar Samuel M. , Peters Peter J. , Brenner Michael B. 
Published: April 2014

AbstractThe presentation of lipid and glycolipid Ags to T cells is mediated through CD1 molecules. In the mouse and rat only a single isoform, CD1d, performs these functions, while humans and all other mammals studied have members of both group I (CD1a, -b, and -c) and group II (CD1d) isoforms. Murine CD1d contains a cytoplasmic tyrosine-based sorting motif that is similar to motifs recognized by adaptor protein complexes that sort transmembrane proteins. Here we show that the adaptor protein complex, AP-3, directly interacts with murine CD1d and controls its targeting to lysosomes. AP-3 deficiency results in a redistribution of CD1d from lysosomes to the cell surface of thymocytes, B cell-depleted splenocytes, and dendritic cells. The altered trafficking of CD1d in AP-3-deficient mice results in a significant reduction of NK1.1+TCR-β+ and CD1d tetramer-positive cells, consistent with a defect in CD1d self-Ag presentation and thymocyte-positive selection. The AP-3 complex has recently been shown to associate with the human CD1b isoform, which has an intracellular distribution pattern similar to that of murine CD1d. We propose that lysosomal sampling may be so critical for efficient host defense that mice have evolved mechanisms to target their single CD1 isoform to lysosomes for sampling lipid Ags. Here we show the dominant mechanism for this trafficking is mediated by AP-3.
Blockade of B7-H1 Suppresses the Development of Chronic Intestinal Inflammation
Authors: Kanai Takanori , Totsuka Teruji , Uraushihara Koji , Makita Shin , Nakamura Tetsuya , Koganei Kazutaka , Fukushima Tsuneo , Akiba Hisaya , Yagita Hideo , Okumura Ko , Machida Utako , Iwai Hideyuki , Azuma Miyuki , Chen Lieping , Watanabe Mamoru 
Published: April 2014

Abstract
A newly identified costimulatory molecule, programmed death-1 (PD-1), provides a negative signal that is essential for immune homeostasis. However, it has been suggested that its ligands, B7-H1 (PD-L1) and B7-dendritic cells (B7-DC; PD-L2), could also costimulate T cell proliferation and cytokine secretion. Here we demonstrate the involvement of PD-1/B7-H1 and B7-DC interaction in the development of colitis. We first examined the expression profiles of PD-1 and its ligands in both human inflammatory bowel disease and a murine chronic colitis model induced by adoptive transfer of CD4+CD45RBhigh T cells to SCID mice. Second, we assessed the therapeutic potential of neutralizing anti-B7-H1 and/or B7-DC mAbs using this colitis model. We found significantly increased expression of PD-1 on T cells and of B7-H1 on T, B, and macrophage/DCs in inflamed colon from both inflammatory bowel disease patients and colitic mice. Unexpectedly, the administration of anti-B7-H1, but not anti-B7-DC, mAb after transfer of CD4+CD45RBhigh T cells suppressed wasting disease with colitis, abrogated leukocyte infiltration, and reduced the production of IFN-γ, IL-2, and TNF-α, but not IL-4 or IL-10, by lamina propria CD4+ T cells. These data suggest that the interaction of PD-1/B7-H1, but not PD-1/B7-DC, might be involved in intestinal mucosal inflammation and also show a possible role of interaction between B7-H1 and an as yet unidentified receptor for B7-H1 in inducing T cell activation.
Ex Vivo Analysis of Thymic CD4 T Cells in Nonobese Diabetic Mice with Tetramers Generated from I-Ag7/Class II-Associated Invariant Chain Peptide Precursors
Authors: Jang Mei-Huei , Seth Nilufer P. , Wucherpfennig Kai W. 
Published: April 2014

Abstract
The MHC determines susceptibility and resistance to type 1 diabetes in humans and nonobese diabetic (NOD) mice. To investigate how a disease-associated MHC molecule shapes the T cell repertoire in NOD mice, we generated a series of tetramers from I-Ag7/class II-associated invariant chain peptide precursors by peptide exchange. No CD4 T cell populations could be identified for two glutamic acid decarboxylase 65 peptides, but tetramers with a peptide mimetic recognized by the BDC-2.5 and other islet-specific T cell clones labeled a distinct population in the thymus of young NOD mice. Tetramer-positive cells were identified in the immature CD4+CD8low population that arises during positive selection, and in larger numbers in the more mature CD4+CD8− population. Tetramer labeling was specific based on the use of multiple control tetramers, including one with a single amino acid analog peptide in which a critical TCR contact residue was substituted. The T cell population was already present in the thymus of 2-wk-old NOD mice before the typical onset of insulitis and was detected in B10 mice congenic for the NOD MHC locus, but not B10 control mice. These results demonstrate that a T cell population can expand in the thymus of NOD mice to levels that are at least two to three orders of magnitude higher than estimated for a given specificity in the naive T cell pool. Based on these data, we propose a model in which I-Ag7 confers susceptibility to type 1 diabetes by biasing positive selection in the thymus and later presenting peptides from islet autoantigens to such T cells in the periphery.
IFN-γ-Induced MHC Class II Expression: Transactivation of Class II Transactivator Promoter IV by IFN Regulatory Factor-1 is Regulated by Protein Kinase C-α
Authors: Giroux Mélanie , Schmidt Manuel , Descoteaux Albert 
Published: April 2014

AbstractPrevious studies based on pharmacological evidence suggested a requirement for protein kinase C (PKC) activity in the regulation of IFN-γ-induced MHC class II (MHC-II) expression. In the present study, we investigated the molecular mechanisms by which PKC-α modulates IFN-γ-induced MHC-II expression in the mouse macrophage cell line RAW 264.7. Overexpression of a dominant-negative (DN) mutant of PKC-α inhibited the expression of IFN-γ-induced MHC-II but had no effect on IFN-γ-induced STAT1 nuclear translocation and DNA binding activity, as well as on the expression of inducible NO synthase, IFN consensus sequence binding protein, MHC class I, IFN regulatory factor (IRF)-1, and IFN-γ-inducible protein-10. Further analysis showed that IFN-γ-induced expression of the MHC class II transactivator (CIITA), a transcriptional coactivator essential for MHC-II expression, was inhibited in DN PKC-α-overexpressing cells. Studies with reporter constructs containing the promoter IV region of CIITA revealed that overexpression of a constitutively active mutant of PKC-α enhanced IRF-1, but not IRF-2, transcriptional activity. Furthermore, characterization of IRF-1 from both normal and DN PKC-α-overexpressing cells revealed differences in IRF-1 posttranslational modifications. Collectively, our data suggest a novel regulatory mechanism for IFN-γ-induced MHC-II expression, whereby PKC regulates CIITA expression by selectively modulating the transcriptional activity of IRF-1.
Phosphatidylcholine-Specific Phospholipase C Activity Is Necessary for the Activation of STAT6
Authors: Zamorano Jose , Rivas Maria Dolores , Garcia-Trinidad Antonio , Qu Cheng-Kui , Keegan Achsah D. 
Published: April 2014

AbstractIt is well established that Janus kinase (JAK) tyrosine kinases play a key role in the activation of STAT6 by IL-4. In this study, we investigated additional molecules involved in this process. We previously found that IL-4 and TNF-α cooperate in the activation of STAT6 and NF-κB, suggesting that these transcription factors are regulated by common intracellular signaling pathways. To test this hypothesis, we analyzed the effect of known inhibitors of NF-κB on the activation of STAT6. We discovered that inhibitors of phosphatidylcholine-specific phospholipase C (PC-PLC), but not other lipases, blocked the activation of STAT6 by IL-4. The activation of PC-PLC seems to be an early event in IL-4 signaling, because its inhibition abrogated JAK activation and STAT6 tyrosine phosphorylation. Interestingly, we found that the effects of pervanadate and sodium orthovanadate on STAT6 activation correspond to their effect on PC-PLC. Thus, pervanadate by itself activated PC-PLC, JAK, and STAT6, whereas sodium orthovanadate suppressed PC-PLC, JAK, and STAT6 activation by IL-4. We further found that PC-PLC activation is necessary but not sufficient to promote STAT6 activation, and therefore, additional intracellular pathways regulated by IL-4 and pervanadate may collaborate with PC-PLC to signal STAT6 activation. It has been reported that IL-4 signals PC-PLC activation; in this study, we provide evidence that this phospholipase plays a key role in IL-4 signaling.
Dual Phosphorylation of Phosphoinositide 3-Kinase Adaptor Grb2-Associated Binder 2 Is Responsible for Superoxide Formation Synergistically Stimulated by Fcγ and Formyl-Methionyl-Leucyl-Phenylalanine Receptors in Differentiated THP-1 Cells
Authors: Momose Haruka , Kurosu Hiroshi , Tsujimoto Noriko , Kontani Kenji , Tsujita Kyoko , Nishina Hiroshi , Katada Toshiaki 
Published: April 2014

Abstract
The class Ia phosphoinositide (PI) 3-kinase consisting of p110 catalytic and p85 regulatory subunits is activated by Tyr kinase-linked membrane receptors such as FcγRII through the association of p85 with the phosphorylated receptors or adaptors. The heterodimeric PI 3-kinase is also activated by G protein-coupled chemotactic fMLP receptors, and activation of the lipid kinase plays an important role in various immune responses, including superoxide formation in neutrophils. Although fMLP-induced superoxide formation is markedly enhanced in FcγRII-primed neutrophils, the molecular mechanisms remain poorly characterized. In this study, we identified two Tyr-phosphorylated proteins, c-Cbl (Casitas B-lineage lymphoma) and Grb2-associated binder 2 (Gab2), as PI 3-kinase adaptors that are Tyr phosphorylated upon the stimulation of FcγRII in differentiated neutrophil-like THP-1 cells. Interestingly, Gab2 was, but c-Cbl was not, further Ser/Thr phosphorylated by fMLP. Thus, the adaptor Gab2 appeared to be dually phosphorylated at the Ser/Thr and Tyr residues through the two different types of membrane receptors. The Ser/Thr phosphorylation of Gab2 required the activation of extracellular signal-regulated kinase, and fMLP receptor stimulation indeed activated extracellular signal-regulated kinase in the cells. Enhanced superoxide formation in response to Fcγ and fMLP was markedly attenuated when the Gab2 Ser/Thr phosphorylation was inhibited. These results show the importance of the dual phosphorylation of PI 3-kinase adaptor Gab2 for the enhanced superoxide formation in neutrophil-type cells.
Deficient Anti-Listerial Immunity in the Absence of Perforin Can Be Restored by Increasing Memory CD8+ T Cell Numbers
Authors: Messingham Kelly A. Nordyke , Badovinac Vladimir P. , Harty John T. 
Published: April 2014

AbstractCompared with wild-type (WT) mice, Listeria monocytogenes (LM)-vaccinated perforin-deficient (PKO) mice have elevated levels of CD8+ T cell memory, but exhibit reduced levels of protection against virulent LM. In this study, Ag-specific CD8+ T cells from LM-vaccinated WT and PKO mice were used in adoptive transfer assays to determine the contribution of perforin-dependent cytolysis in protective immunity to LM. Perforin deficiency resulted in an ∼5-fold reduction in the per-cell protective capacity of Ag-specific memory CD8+ T cells that was not caused by differences in memory cell quality as measured by CD62L/CD27 expression, TCR repertoire use, functional avidity, differences in expansion of Ag-specific cells upon infection, or maintenance of memory levels over time. However, perforin-deficient CD8+ T cells exhibited reduced in vivo cytotoxic function compared to WT CD8+ T cells. Consistent with the existence of perforin-independent effector pathways, double-vaccinated PKO mice were as resistant to challenge with LM as single-vaccinated WT mice. Thus, increasing the number of memory CD8+ T cells can overcome diminished per-cell protective immunity in the absence of perforin.
Functional Characterization of Class Ia- and Non-Class Ia-RestrictedChlamydia-Reactive CD8+ T Cell Responses in Humans
Authors: Gervassi Ana L. , Probst Peter , Stamm Walter E. , Marrazzo Jeanne , Grabstein Kenneth H. , Alderson Mark R. 
Published: April 2014

AbstractCD8+ T cells are a key immune component for the eradication of many intracellular pathogens. This study aims to characterize the human CD8+ T cell response to naturally processed chlamydial Ags in individuals exposed to the intracellular pathogen Chlamydia trachomatis. By using C. trachomatis-infected autologous dendritic cells (DCs) as stimulators, Chlamydia-reactive CD8+ T cell responses were detected in all 10 individuals tested. The majority of the Chlamydia-reactive CD8+ T cells were non-MHC class Ia restricted in all three of the individuals tested. From one donor, three non-class Ia-restricted and two class Ia-restricted Chlamydia-specific CD8+ T cells were cloned and characterized further. All five T cell clones secreted IFN-γ in response to autologous DCs infected with viable Chlamydia, but not with DCs pulsed with inactivated chlamydial elementary bodies. MHC class Ia-restricted and non-class Ia-restricted responses were inhibited by DC treatment with a proteasomal inhibitor and an endoplasmic reticulum-Golgi transport inhibitor, suggesting that these T cells recognize a peptide Ag translocated to the host cell cytosol during infection that is processed via the classical class Ia Ag-processing pathway. Even though both restricted and nonrestricted CD8+ T cells produced IFN-γ in response to Chlamydia-infected fibroblasts, only the non-class Ia-restricted cells were lytic for these targets. The class Ia-restricted CTLs, however, were capable of cytolysis as measured by redirected killing. Collectively, these data demonstrate that both class Ia-restricted and non-classically restricted CD8+ T cells are elicited in C. trachomatis-exposed individuals. Their role in host immunity remains to be elucidated.
A Dominant Role of Toll-Like Receptor 4 in the Signaling of Apoptosis in Bacteria-Faced Macrophages
Authors: Haase Rudolf , Kirschning Carsten J. , Sing Andreas , Schröttner Percy , Fukase Koichi , Kusumoto Shoichi , Wagner Hermann , Heesemann Jürgen , Ruckdeschel Klaus 
Published: April 2014

AbstractConserved bacterial components potently activate host immune cells through transmembrane Toll-like receptors (TLRs), which trigger a protective immune response but also may signal apoptosis. In this study, we investigated the roles of TLR2 and TLR4 as inducers of apoptosis in Yersinia enterocolitica-infected macrophages. Yersiniae suppress activation of the antiapoptotic NF-κB signaling pathway in host cells by inhibiting inhibitory κB kinase-β. This leads to macrophage apoptosis under infection conditions. Experiments with mouse macrophages deficient for TLR2, TLR4, or both receptors showed that, although yersiniae could activate signaling through both TLR2 and TLR4, loss of TLR4 solely diminished Yersinia-induced apoptosis. This suggests implication of TLR4, but not of TLR2, as a proapoptotic signal transducer in Yersinia-conferred cell death. In the same manner, agonist-specific activation of TLR4 efficiently mediated macrophage apoptosis in the presence of the proteasome inhibitor MG-132, an effect that was less pronounced for activation through TLR2. Furthermore, the extended stimulation of overexpressed TLR4 elicited cellular death in epithelial cells. A dominant-negative mutant of Fas-associated death domain protein could suppress TLR4-mediated cell death, which indicates that TLR4 may signal apoptosis through a Fas-associated death domain protein-dependent pathway. Together, these data show that TLR4 could act as a potent inducer of apoptosis in macrophages that encounter a bacterial pathogen.