bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exosomes as Potent Cell-Free Peptide-Based Vaccine. I. Dendritic Cell-Derived Exosomes Transfer Functional MHC Class I/Peptide Complexes to Dendritic Cells
Authors: André Fabrice , Chaput Nathalie , Schartz Nöel E. C. , Flament Caroline , Aubert Nathalie , Bernard Jacky , Lemonnier François , Raposo Graça , Escudier Bernard , Hsu Di-Hwei , Tursz Thomas , Amigorena Sebastian , Angevin Eric , Zitvogel Laurence 
Published: April 2014

Abstract
Current immunization protocols in cancer patients involve CTL-defined tumor peptides. Mature dendritic cells (DC) are the most potent APCs for the priming of naive CD8+ T cells, eventually leading to tumor eradication. Because DC can secrete MHC class I-bearing exosomes, we addressed whether exosomes pulsed with synthetic peptides could subserve the DC function consisting in MHC class I-restricted, peptide-specific CTL priming in vitro and in vivo. The priming of CTL restricted by HLA-A2 molecules and specific for melanoma peptides was performed: 1) using in vitro stimulations of total blood lymphocytes with autologous DC pulsed with GMP-manufactured autologous exosomes in a series of normal volunteers; 2) in HLA-A2 transgenic mice (HHD2) using exosomes harboring functional HLA-A2/Mart1 peptide complexes. In this study, we show that: 1) DC release abundant MHC class I/peptide complexes transferred within exosomes to other naive DC for efficient CD8+ T cell priming in vitro; 2) exosomes require nature’s adjuvants (mature DC) to efficiently promote the differentiation of melanoma-specific effector T lymphocytes producing IFN-γ (Tc1) effector lymphocytes in HLA-A2 transgenic mice (HHD2). These data imply that exosomes might be a transfer mechanism of functional MHC class I/peptide complexes to DC for efficient CTL activation in vivo.
Exosomes as Potent Cell-Free Peptide-Based Vaccine. II. Exosomes in CpG Adjuvants Efficiently Prime Naive Tc1 Lymphocytes Leading to Tumor Rejection
Authors: Chaput Nathalie , Schartz Nöel E. C. , André Fabrice , Taïeb Julien , Novault Sophie , Bonnaventure Pierre , Aubert Nathalie , Bernard Jacky , Lemonnier François , Merad Miriam , Adema Gosse , Adams Malcolm , Ferrantini Maria , Carpentier Antoine F. , Escudier Bernard , Tursz Thomas , Angevin Eric , Zitvogel Laurence 
Published: April 2014

Abstract
Ideal vaccines should be stable, safe, molecularly defined, and out-of-shelf reagents efficient at triggering effector and memory Ag-specific T cell-based immune responses. Dendritic cell-derived exosomes could be considered as novel peptide-based vaccines because exosomes harbor a discrete set of proteins, bear functional MHC class I and II molecules that can be loaded with synthetic peptides of choice, and are stable reagents that were safely used in pioneering phase I studies. However, we showed in part I that exosomes are efficient to promote primary MHC class I-restricted effector CD8+ T cell responses only when transferred onto mature DC in vivo. In this work, we bring evidence that among the clinically available reagents, Toll-like receptor 3 and 9 ligands are elective adjuvants capable of triggering efficient MHC-restricted CD8+ T cell responses when combined to exosomes. Exosome immunogenicity across species allowed to verify the efficacy of good manufactory procedures-manufactured human exosomes admixed with CpG oligonucleotides in prophylactic and therapeutic settings of melanoma in HLA-A2 transgenic mice. CpG adjuvants appear to be ideal adjuvants for exosome-based cancer vaccines.
Novel Regulatory Mechanisms of CD40-Induced Prostanoid Synthesis by IL-4 and IL-10 in Human Monocytes
Authors: Inoue Yasushi , Otsuka Takeshi , Niiro Hiroaki , Nagano Shuji , Arinobu Yojirou , Ogami Eiichi , Akahoshi Mitsuteru , Miyake Katsuhisa , Ninomiya Ichiro , Shimizu Sakiko , Nakashima Hitoshi , Harada Mine 
Published: April 2014

AbstractInterleukins IL-4 and IL-10 are considered to be central regulators for the limitation and eventual termination of inflammatory responses in vivo, based on their potent anti-inflammatory effects toward LPS-stimulated monocytes/macrophages and neutrophils. However, their role in T cell-dependent inflammatory responses has not been fully elucidated. In this study, we investigated the effects of both cytokines on the production of PGE2, a key molecule of various inflammatory conditions, in CD40-stimulated human peripheral blood monocytes. CD40 ligation of monocytes induced the synthesis of a significant amount of PGE2 via inducible expression of the cyclooxygenase (COX)-2 gene. Both IL-10 and IL-4 significantly inhibited PGE2 production and COX-2 expression in CD40-stimulated monocytes. Using specific inhibitors for extracellular signal-related kinase (ERK) and p38 mitogen-activated protein kinase (MAPK), we found that both kinase pathways are involved in CD40-induced COX-2 expression. CD40 ligation also resulted in the activation of NF-κB. Additional experiments exhibited that CD40 clearly induced the activation of the upstream kinases MAPK/ERK kinase 1/2, MAPK kinase 3/6, and I-κB in monocytes. IL-10 significantly inhibited CD40-induced activation of the ERK, p38 MAPK, and NF-κB pathways; however, inhibition by IL-4 was limited to the ERK pathway in monocytes. Neither IL-10 nor IL-4 affected the recruitment of TNFR-associated factors 2 and 3 to CD40 in monocytes. Collectively, IL-10 and IL-4 use novel regulatory mechanisms for CD40-induced prostanoid synthesis in monocytes, thus suggesting a potential role for these cytokines in regulating T cell-induced inflammatory responses, including autoimmune diseases.
Reduced Ig Class Switch in Aged Mice Correlates with Decreased E47 and Activation-Induced Cytidine Deaminase
Authors: Frasca Daniela , Van der Put Elaine , Riley Richard L. , Blomberg Bonnie B. 
Published: April 2014

Abstract
The capacity to class switch the IgH chain is critical to the effectiveness of humoral immune responses. We show that in vitro-stimulated splenic B cells from senescent mice are deficient in production of multiple class switch isotypes (IgG1, G2a, G3, and E), class switch recombination (CSR), and induction of the E2A-encoded transcription factor E47. E47 has previously been shown to be required for CSR, at least in part via expression of the activation-induced cytidine deaminase. Our studies show that impaired induction of E47, and subsequently activation-induced cytidine deaminase, contribute to poor CSR and production of secondary isotypes in senescence.
Dependency of Direct Pathway CD4+ T Cells on CD40-CD154 Costimulation Is Determined by Nature and Microenvironment of Primary Contact with Alloantigen
Authors: van Maurik Andre , de St. Groth Barbara Fazekas , Wood Kathryn J. , Jones Nick D. 
Published: April 2014

Abstract
Blockade of the CD40-CD154 costimulatory pathway can inhibit CD4+ T cell-mediated alloimmune responses. The aim of this study was to define the in vivo requirement for CD40-CD154 costimulation by CD4+ T cells that respond to alloantigen following direct recognition. We used TCR-transgenic CD4+ T cells that are reactive to the MHC class II alloantigen, H2As. An experimental in vivo model was established that allowed direct comparison of the fate of a trace population of H2As-reactive CD4+ T cells when challenged with different forms of H2As+ alloantigen under conditions of CD40-CD154 costimulation blockade. In this study, we demonstrate that an i.v. infusion of H2As+ leukocytes in combination with anti-CD154 therapy rapidly deletes H2As-reactive CD4+ T cells. In contrast, following transplantation of an H2As+ cardiac allograft, H2As-reactive CD4+ T cell responses were unaffected by blocking CD40-CD154 interactions. Consistent with these findings, combined treatment with donor leukocytes and anti-CD154 therapy was found to be more effective in prolonging the survival of cardiac allografts compared with CD154 mAb treatment alone. The dominant mechanism by which donor leukocyte infusion and anti-CD154 therapy facilitate allograft acceptance is deletion of donor-reactive direct pathway T cells. No evidence for the generation of regulatory cells by this combined therapy was found. Taken together, these results clearly demonstrate that naive alloreactive CD4+ T cells have distinct requirements for CD40-CD154 costimulation depending on the form and microenvironment of primary alloantigen contact.
A Novel Role for an Insect Apolipoprotein (Apolipophorin III) in β-1,3-Glucan Pattern Recognition and Cellular Encapsulation Reactions
Authors: Whitten Miranda M. A. , Tew Ian F. , Lee Bok L. , Ratcliffe Norman A. 
Published: April 2014

Abstract
Lipoproteins and molecules for pattern recognition are centrally important in the innate immune response of both vertebrates and invertebrates. Mammalian apolipoproteins such as apolipoprotein E (apoE) are involved in LPS detoxification, phagocytosis, and possibly pattern recognition. The multifunctional insect protein, apolipophorin III (apoLp-III), is homologous to apoE. In this study we describe novel roles for apoLp-III in pattern recognition and multicellular encapsulation reactions in the innate immune response, which may be of direct relevance to mammalian systems. It is known that apoLp-III stimulates antimicrobial peptide production in insect blood, enhances phagocytosis by insect blood cells (hemocytes), and binds and detoxifies LPS and lipoteichoic acid. In the present study we show that apoLp-III from the greater wax moth, Galleria mellonella, also binds to fungal conidia and β-1,3-glucan and therefore may act as a pattern recognition molecule for multiple microbial and parasitic invaders. This protein also stimulates increases in cellular encapsulation of nonself particles by the blood cells and exerts shorter term, time-dependent, modulatory effects on cell attachment and spreading. All these responses are dose dependent, occur within physiological levels, and, with the notable exception of β-glucan binding, are only observed with the lipid-associated form of apoLp-III. Preliminary studies also established a beneficial role for apoLp-III in the in vivo response to an entomopathogenic fungus. These data suggest a wide range of immune functions for a multiple specificity pattern recognition molecule and may provide a useful model for identifying further potential roles for homologous proteins in mammalian immunology, particularly in terms of fungal infections, pneumoconiosis, and granulomatous reactions.
Extremely Rapid and Intense Induction of Apoptosis in Human Eosinophils by Anti-CD30 Antibody Treatment In Vitro
Authors: Matsumoto Kenji , Terakawa Maki , Miura Kenju , Fukuda Shuhei , Nakajima Toshiharu , Saito Hirohisa 
Published: April 2014

Abstract
Apoptosis is an important cellular mechanism for controlling cell viability and proliferation. With respect to eosinophils, cytokines prolong their survival, whereas corticosteroids reduce their survival in vitro. CD30, a member of the TNFR family, is expressed on the surface of many cell types, including Hodgkin’s lymphoma cells. CD30 is capable of inducing apoptosis after Ab treatment in some cell lines. To determine whether this surface structure is involved in apoptosis of human eosinophils, we examined its expression and the effect of anti-CD30 Ab treatment on the viability of eosinophils. Purified human eosinophils expressed low, but consistently detectable, levels of CD30. Immobilized, but not soluble, forms of anti-CD30 Abs (HRS-4 and Ber-H8) or recombinant mouse CD30 ligand exhibited an extremely rapid and intense survival-reducing effect on the eosinophils in the presence of exogenous IL-5; this effect was both concentration and time dependent. Furthermore, high concentrations of IL-5 could not reverse the reduced survival rates. After treatment with anti-CD30 Ab, gel electrophoresis of DNA extracted from the eosinophils demonstrated changes consistent with apoptosis. The immobilized F(ab′)2 of the anti-CD30 Ab failed to induce eosinophil apoptosis. The addition of anti-CD18 Ab also completely abrogated the induction of eosinophil apoptosis. Further examination using specific signal transduction inhibitors suggested the involvement of p38, mitogen-activated protein kinase kinase 1/2, and specific tyrosine kinase, but not NF-κB, in the induction of CD30-mediated eosinophil apoptosis. These data demonstrate that CD30 can modify eosinophil survival by causing an extremely rapid and intense induction of apoptosis through a tightly regulated intracellular signaling pathway.
The Cytoplasmic Domain of Igα Is Necessary and Sufficient to Support Efficient Early B Cell Development
Authors: Pike Kelly A. , Iacampo Sandra , Friedmann Jennifer E. , Ratcliffe Michael J. H. 
Published: April 2014

Abstract
The B cell receptor complex (BcR) is essential for normal B lymphocyte function, and surface BcR expression is a crucial checkpoint in B cell development. However, functional requirements for chains of the BcR during development remain controversial. We have used retroviral gene transfer to introduce components of the BcR into chicken B cell precursors during embryonic development. A chimeric heterodimer, in which the cytoplasmic domains of chicken Igα and Igβ are expressed by fusion with the extracellular and transmembrane domains of murine CD8α and CD8β, respectively, targeted the cytoplasmic domains of the BcR to the cell surface in the absence of extracellular BcR domains. Expression of this chimeric heterodimer supported all early stages of embryo B cell development: bursal colonization, clonal expansion, and induction of repertoire diversification by gene conversion. Expression of the cytoplasmic domain of Igα, in the absence of the cytoplasmic domain of Igβ, was not only necessary, but sufficient to support B cell development as efficiently as the endogenous BcR. In contrast, expression of the cytoplasmic domain of Igβ in the absence of the cytoplasmic domain of Igα failed to support B cell development. The ability of the cytoplasmic domain of Igα to support early B cell development required a functional Igα immunoreceptor tyrosine-based activation motif. These results support a model in which expression of surface IgM following productive V(D)J recombination in developing B cell precursors serves to chaperone the cytoplasmic domain of Igα to the B cell surface, thereby initiating subsequent stages of development.
HIV-Infected Langerhans Cells Preferentially Transmit Virus to Proliferating Autologous CD4+ Memory T Cells Located within Langerhans Cell-T Cell Clusters
Authors: Sugaya Makoto , Loré Karin , Koup Richard A. , Douek Daniel C. , Blauvelt Andrew 
Published: April 2014

Abstract
Langerhans cells (LC) are likely initial targets for HIV following sexual exposure to virus and provide an efficient means for HIV to gain access to lymph node T cells. The purpose of this study was to examine the nature of the CD4+ T cell that becomes infected by HIV-infected LC. We infected human LC within tissue explants ex vivo and then, 3 days later, cocultured HIV-infected LC with different subsets of autologous CD4+ T cells. Using multicolor flow cytometric analyses of LC-CD4+ T cell cocultures, we documented that HIV-infected LC preferentially infected memory (as compared with naive) CD4+ T cells. Proliferating and HIV-infected CD4+ memory T cells were more frequently detected in conjugates of LC and autologous CD4+ T cells, suggesting that T cells become activated and preferentially get infected through cluster formation with infected LC, rather than getting infected with free virus produced by single HIV-infected LC or T cells. p24+ Memory CD4+ T cells proliferated well in the absence of superantigen; by contrast, p24+ T cells did not divide or divided only once in the presence of staphylococcal enterotoxin B, suggesting that virus production was rapid and induced apoptosis in these cells before significant proliferation could occur. These results highlight that close interactions between dendritic cells, in this case epidermal LC, and T cells are important for optimal HIV replication within specific subsets of CD4+ T cells. Disrupting cluster formation between LC and memory CD4+ T cells may be a novel strategy to interfere with sexual transmission of HIV.
WSX-1 and Glycoprotein 130 Constitute a Signal-Transducing Receptor for IL-27
Authors: Pflanz Stefan , Hibbert Linda , Mattson Jeanine , Rosales Rency , Vaisberg Elena , Bazan J. Fernando , Phillips Joseph H. , McClanahan Terrill K. , de Waal Malefyt Rene , Kastelein Robert A. 
Published: April 2014

AbstractThe recently discovered cytokine IL-27 belongs to the IL-6/IL-12 family of cytokines and induced proliferation of naive CD4+ T cells and the generation of a Th1-type adaptive immune response. Although binding of IL-27 to the cytokine receptor WSX-1 was demonstrated, this interaction proved insufficient to mediate cellular effects. Hence, IL-27 was believed to form a heteromeric signaling receptor complex with WSX-1 and another, yet to be identified, cytokine receptor subunit. In this study, we describe that WSX-1 together with gp130 constitutes a functional signal-transducing receptor for IL-27. We show that neither of the two subunits itself is sufficient to mediate IL-27-induced signal transduction, but that the combination of both is required for this event. Expression analysis of WSX-1 and gp130 by quantitative PCR suggests that IL-27 might have a variety of cellular targets besides naive CD4+ T cells: we demonstrate gene induction of a subset of inflammatory cytokines in primary human mast cells and monocytes in response to IL-27 stimulation. Thus, IL-27 not only contributes to the development of an adaptive immune response through its action on CD4+ T cells, it also directly acts on cells of the innate immune system.
Antigen Nonspecific Suppression of T Cell Responses by Activated Stimulation-Refractory CD4+ T Cells
Authors: Duthoit Christine T. , Nguyen Phuong , Geiger Terrence L. 
Published: April 2014

Abstract
Several classes of anergic T cells are capable of suppressing naive T cell proliferation and thereby limiting immune responses. Activated T cells, although not anergic, are transiently refractory to restimulation with Ag. We examine in this study whether activated refractory murine T cells can also suppress naive T cell responses. We find that they can, and that they exhibit many of the suppressive properties of anergic T cells. The activated cells strongly diminish Ag-mediated T cell proliferation, an activity that correlates with their refractory period. Suppression is independent of APC numbers and requires cell contact or proximity. Naive T cells stimulated in the presence of activated refractory cells up-regulate CD25 and CD69, but fail to produce IL-2. The addition of IL-2 to culture medium, however, does not prevent the suppression, which is therefore not solely due to the absence of this growth factor. Persistence of the suppressor cells is also not essential. T cells stimulated in their presence and then isolated from them and cultured do not divide. The suppressive cells, however, do not confer a refractory or anergic state on the target T lymphocytes, which can fully respond to antigenic stimulation if removed from the suppressors. Our results therefore provide evidence that activated T cells act as transient suppressor cells, severely constraining bystander T cell stimulation and thereby restricting their response. These results have potentially broad implications for the development and regulation of immune responses.
The Impact of Thymic Antigen Diversity on the Size of the Selected T Cell Repertoire
Authors: Faro Jose , Velasco Santiago , González-Fernández África , Bandeira Antonio 
Published: April 2014

Abstract
The TCR repertoire of a normal animal is shaped in the thymus by ligand-specific positive- and negative-selection events. These processes are believed to be determined at the single-cell level primarily by the affinity of the TCR-ligand interactions. The relationships among all the variables involved are still unknown due to the complexity of the interactions and the lack of quantitative analysis of those parameters. In this study, we developed a quantitative model of thymic selection that provides estimates of the fractions of positively and negatively selected thymocytes in the cortex and in the medulla, as well as upper-bound ranges for the number of selecting ligands required for the generation of a normal diverse TCR repertoire. Fitting the model to current estimates of positive- and negative-selected thymocytes leads to specific predictions. The results indicate the following: 1) the bulk of thymocyte death takes place in the cortex, and it is due to neglect; 2) the probability of a thymocyte to be negatively selected in the cortex is at least 10-fold lower than in the medulla; 3) &lt;60 ligands are involved in cortical positive selection; and 4) negative selection in the medulla is constrained by a large diversity of selecting ligands on medullary APCs.
Human Cytomegalovirus Proteins pp65 and Immediate Early Protein 1 Are Common Targets for CD8+ T Cell Responses in Children with Congenital or Postnatal Human Cytomegalovirus Infection
Authors: Gibson Laura , Piccinini Giampiero , Lilleri Daniele , Revello Maria Grazia , Wang Zhongde , Markel Susan , Diamond Don J. , Luzuriaga Katherine 
Published: April 2014

Abstract
Recombinant modified vaccinia Ankara- and peptide-based IFN-γ ELISPOT assays were used to detect and measure human CMV (HCMV)-specific CD8+ T cell responses to the pp65 (UL83) and immediate early protein 1 (IE1; UL123) gene products in 16 HCMV-infected infants and children. Age at study ranged from birth to 2 years. HCMV-specific CD8+ T cells were detected in 14 (88%) of 16 children at frequencies ranging from 60 to &gt;2000 spots/million PBMC. Responses were detected as early as 1 day of age in infants with documented congenital infection. Nine children responded to both pp65 and IE1, whereas responses to pp65 or IE1 alone were detected in three and two children, respectively. Regardless of the specificity of initial responses, IE1-specific responses predominated by 1 year of age. Changes in HCMV epitopes targeted by the CD8+ T cell responses were observed over time; epitopes commonly recognized by HLA-A2+ adults with latent HCMV infection did not fully account for responses detected in early childhood. Finally, the detection of HCMV-specific CD8+ T cell responses was temporally associated with a decrease in peripheral blood HCMV load. Taken altogether, these data demonstrate that the fetus and young infant can generate virus-specific CD8+ T cell responses. Changes observed in the protein and epitope-specificity of HCMV-specific CD8+ T cells over time are consistent with those observed after other primary viral infections. The temporal association between the detection of HCMV-specific CD8+ T cell responses and the reduction in blood HCMV load supports the importance of CD8+ T cells in controlling primary HCMV viremia.