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Sample records for antigen presentation capability

  1. Germinal center B cells regulate their capability to present antigen by modulation of HLA-DO.

    PubMed

    Glazier, Kim S; Hake, Sandra B; Tobin, Helen M; Chadburn, Amy; Schattner, Elaine J; Denzin, Lisa K

    2002-04-15

    Peptide acquisition by MHC class II molecules is catalyzed by HLA-DM (DM). In B cells, HLA-DO (DO) inhibits or modifies the peptide exchange activity of DM. We show here that DO protein levels are modulated during B cell differentiation. Remarkably, germinal center (GC) B cells, which have low levels of DO relative to naive and memory B cells, are shown to have enhanced antigen presentation capabilities. DM protein levels also were somewhat reduced in GC B cells; however, the ratio of DM to DO in GC B cells was substantially increased, resulting in more free DM in GC B cells. We conclude that modulation of DM and DO in distinct stages of B cell differentiation represents a mechanism by which B cells regulate their capacity to function as antigen-presenting cells. Efficient antigen presentation in GC B cells would promote GC B cell-T cell interactions that are essential for B cells to survive positive selection in the GC.

  2. Equine infectious anemia virus-infected dendritic cells retain antigen presentation capability

    SciTech Connect

    Rivera, Julie A.; McGuire, Travis C. . E-mail: mcguiret@vetmed.wsu.edu

    2005-05-10

    To determine if equine monocyte-derived dendritic cells (DC) were susceptible to equine infectious anemia virus (EIAV) infection, ex vivo-generated DC were infected with virus in vitro. EIAV antigen was detected by immunofluorescence 3 days post-infection with maximum antigen being detected on day 4, whereas there was no antigen detected in DC incubated with the same amount of heat-inactivated EIAV. No cytolytic activity was observed after EIAV{sub WSU5} infection of DC. These monocyte-derived DC were more effective than macrophages and B cells in stimulating allogenic T lymphocytes. Both infected macrophages and DC stimulated similar levels of memory CTL responses in mixtures of CD8+ and CD4+ cells as detected with {sup 51}Cr-release assays indicating that EIAV infection of DC did not alter antigen presentation. However, EIAV-infected DC were more effective than infected macrophages when used to stimulate memory CTL in isolated CD8+ cells. The maintenance of antigen processing and presenting function by EIAV-infected DC in vitro suggests that this function is maintained during in vivo infection.

  3. The peripheral blood fibrocyte is a potent antigen-presenting cell capable of priming naive T cells in situ.

    PubMed

    Chesney, J; Bacher, M; Bender, A; Bucala, R

    1997-06-10

    Recent studies have identified a novel population of blood-borne cells, termed fibrocytes, that have a distinct cell surface phenotype (collagen+/CD13(+)/CD34(+)/CD45(+)), rapidly enter sites of tissue injury, and synthesize connective tissue matrix molecules. We found by flow cytometry that purified human fibrocytes express each of the known surface components that are required for antigen presentation, including class II major histocompatability complex molecules (HLA-DP, -DQ, and -DR), the costimulatory molecules CD80 and CD86, and the adhesion molecules CD11a, CD54, and CD58. Human fibrocytes induced antigen-presenting cell-dependent T cell proliferation when cultured with specific antigen and this proliferative activity was significantly higher than that induced by monocytes and nearly as high as that induced by purified dendritic cells. Mouse fibrocytes also were found to express the surface components required for antigen presentation and to function as potent APCs in vitro. Mouse fibrocytes pulsed in vitro with the HIV-proteins p24 or gp120 and delivered to a site of cutaneous injury were found to migrate to proximal lymph nodes and to specifically prime naive T cells. These data suggest that fibrocytes play an early and important role in the initiation of antigen-specific immunity.

  4. Expression of XCR1 Characterizes the Batf3-Dependent Lineage of Dendritic Cells Capable of Antigen Cross-Presentation

    PubMed Central

    Bachem, Annabell; Hartung, Evelyn; Güttler, Steffen; Mora, Ahmed; Zhou, Xuefei; Hegemann, Anika; Plantinga, Maud; Mazzini, Elisa; Stoitzner, Patrizia; Gurka, Stephanie; Henn, Volker; Mages, Hans W.; Kroczek, Richard A.

    2012-01-01

    Cross-presentation of antigen by dendritic cells (DCs) to CD8+ T cells is a fundamentally important mechanism in the defense against pathogens and tumors. Due to the lack of an appropriate lineage marker, cross-presenting DCs in the mouse are provisionally classified as “Batf3-IRF-8-Id2-dependent DCs” or as “CD8+ DCs” in the spleen, and as “CD103+CD11b− DCs” in the periphery. We have now generated a mAb to XCR1, a chemokine receptor which is specifically expressed on CD8+ DCs and a subpopulation of double negative DCs in the spleen. Using this antibody, we have determined that only XCR1+CD8+ (around 80% of CD8+ DCs) and their probable precursors, XCR1+CD8− DCs, efficiently take up cellular material and excel in antigen cross-presentation. In lymph nodes (LNs) and peripheral tissues, XCR1+ DCs largely, but not fully, correspond to CD103+CD11b− DCs. Most importantly, we demonstrate that XCR1+ DCs in the spleen, LNs, and peripheral tissues are dependent on the growth factor Flt3 ligand and are selectively absent in Batf3-deficient animals. These results provide evidence that expression of XCR1 throughout the body defines the Batf3-dependent lineage of DCs with a special capacity to cross-present antigen. XCR1 thus emerges as the first surface marker characterizing a DC lineage in the mouse and potentially also in the human. PMID:22826713

  5. Mouse γδ T cells are capable of expressing MHC class II molecules, and of functioning as antigen-presenting cells⋆

    PubMed Central

    Cheng, Lan; Cui, Yan; Shao, Hui; Han, Gencheng; Zhu, Ling; Huang, Yafei; O'Brien, Rebecca L.; Born, Willi K.; Kaplan, Henry J.; Sun, Deming

    2008-01-01

    Although human and bovine γδ T cells were shown to express MHC class II antigen and function as APCs, attempts to determine if mouse γδ T cells have similar functions remained unsuccessful. We now show that γδ T cells derived from immunized mice also can be induced to express MHC class II and co-stimulatory molecules after activation in vitro, and are capable of antigen presentation. Using highly purified γδ T cells, we found that, unlike human γδ T cells, the expression of MHC class II molecules by mouse γδ T cells is limited to newly activated cells. Highest levels of MHC class II expression were seen on activated γδ T cells that had lost most surface-expressed γδ TCR while exhibiting increased levels of intracellular γδ TCR. In the absence of further stimulation, MHC class II expression gradually declined with the γδ T cells regaining their surface TCR. We also show that cytokine-activated γδ T cells can also express MHC class II antigen and exercise antigen-presenting activity. PMID:18774183

  6. A comparison of the antigen-presenting capabilities of class II MHC-expressing human lung epithelial and endothelial cells.

    PubMed Central

    Cunningham, A C; Zhang, J G; Moy, J V; Ali, S; Kirby, J A

    1997-01-01

    Human lung alveolar epithelial cells constitutively express class II major histocompatibility complex (MHC). Human lung microvascular endothelial and small airway epithelial cells can be induced to express class II MHC by stimulation with the pro-inflammatory cytokine interferon-gamma. The levels of class II MHC on lung epithelial and endothelial cells were comparable to those seen on an Epstein-Barr virus (EBV)-transformed B-cell line. However, the costimulatory molecules B7-1 and B7-2 were not expressed. The ability of the class II MHC expressing human lung parenchymal cells to present alloantigen to CD4+ T lymphocytes was investigated. Freshly isolated human alveolar epithelial cells (type II pneumocytes) and monolayers of interferon-gamma-stimulated small airway epithelial and lung microvascular endothelial cells were co-cultured with allogeneic CD4+ T lymphocytes and proliferation determined by [3H]thymidine incorporation. A clear difference was observed between effects of the epithelial and endothelial cells on CD4+ T-lymphocyte activation. Alveolar and small airway epithelial cells failed to stimulate the proliferation of allogeneic CD4+ T lymphocytes whereas lung microvascular endothelial cells did stimulate proliferation. This difference could not be explained by the levels of class II MHC or the lack of B7-1 and B7-2 solely. Microvascular endothelial cells, and not alveolar or small airway epithelial cells, possess B7-independent costimulatory pathways. PMID:9301537

  7. A nonimmunogenic sarcoma transduced with the cDNA for interferon gamma elicits CD8+ T cells against the wild-type tumor: correlation with antigen presentation capability

    PubMed Central

    1992-01-01

    To be recognized by CD8+ T lymphocytes, target cells must process and present peptide antigens in the context of major histocompatibility complex (MHC) class I molecules. The nonimmunogenic, low class I- expressing, methylcholanthrene (MCA)-induced murine sarcoma cell line, MCA 101, is a poor presenter of endogenously generated viral antigens to specific CD8+ T lymphocytes and cannot be used to generate tumor infiltrating lymphocytes (TIL). Since interferon gamma (IFN-gamma) has been shown to upregulate three sets of molecules important for antigen processing and presentation, we retrovirally transduced wild-type MCA 101 (101.WT) tumor with the mIFN-gamma cDNA to create the 101.NAT cell line. Unlike 101.WT, some clones of retrovirally transduced 101.NAT tumor expressed high levels of class I, and could be used to generate CD8+ TIL. More importantly, these TIL were therapeutic in vivo against established pulmonary metastases from the wild-type tumor. Although not uniformly cytotoxic amongst several separate cultures, these TIL did specifically release cytokines (IFN-gamma and tumor necrosis factor- alpha) in response to 101.WT targets. 101.WT's antigen presentation deficit was also reversed by gene modification with mIFN-gamma cDNA. 101.NAT had a greatly improved capacity to present viral antigens to CD8+ cytotoxic T lymphocytes. These findings show that a nonimmunogenic tumor, incapable of generating a CD8+ T cell immune response, could be gene-modified to generate a therapeutically useful immune response against the wild-type tumor. This strategy may be useful in developing treatments for tumor histologies not thought to be susceptible to T cell-based immunotherapy. PMID:1588273

  8. Antigen presentation by Hodgkin's disease cells.

    PubMed

    Fisher, R I; Cossman, J; Diehl, V; Volkman, D J

    1985-11-01

    The L428 tumor cell line is a long-term tissue culture of Reed-Sternberg cells which was derived from the pleural effusion of a patient with Hodgkin's disease. The L428 cells express all known cell surface antigens, cytochemical staining, and cytologic features of freshly explanted Reed-Sternberg cells. In addition to the previously described HLA-DR cell surface antigens, the L428 cells are now demonstrated to express both DS and SB alloantigens. Thus, the L428 cells express all of the known subclasses of the human immune response genes that are located in the major histocompatibility complex. Furthermore, the L428 cells are capable of presenting soluble antigen to T cells in a genetically restricted fashion. T cell lines were established from normal donors previously immunized with tetanus toxoid. The T cells utilized were incapable of tetanus toxoid-induced proliferation unless antigen-presenting cells were added to the cultures. However, T cells from the two normal donors, which like the L428 cells expressed HLA-DR 5, demonstrated significant proliferative responses when cultured with tetanus toxoid and L428 cells. No proliferative response was observed when the L428 cells were used as antigen-presenting cells for a DR (4,-), DR (2,-) or DR (1,7) T cell line. The tetanus toxoid dose-response curve was similar regardless of whether autologous mononuclear leukocytes or L428 cells were used as antigen-presenting cells. The T cell proliferation induced by soluble antigen was also blocked by anti-HLA-DR antibody. Thus, functionally, Hodgkin's disease may be classified as a tumor of antigen-presenting cells.

  9. Mycobacterium tuberculosis Synergizes with ATP To Induce Release of Microvesicles and Exosomes Containing Major Histocompatibility Complex Class II Molecules Capable of Antigen Presentation ▿ †

    PubMed Central

    Ramachandra, Lakshmi; Qu, Yan; Wang, Ying; Lewis, Colleen J.; Cobb, Brian A.; Takatsu, Kiyoshi; Boom, W. Henry; Dubyak, George R.; Harding, Clifford V.

    2010-01-01

    Major histocompatibility complex class II (MHC-II) molecules are released by murine macrophages upon lipopolysaccharide (LPS) stimulation and ATP signaling through the P2X7 receptor. These studies show that infection of macrophages with Mycobacterium tuberculosis or M. bovis strain BCG enhances MHC-II release in synergy with ATP. Shed MHC-II was contained in two distinct organelles, exosomes and plasma membrane-derived microvesicles, which were both able to present exogenous antigenic peptide to T hybridoma cells. Furthermore, microvesicles from mycobacterium-infected macrophages were able to directly present M. tuberculosis antigen (Ag) 85B(241-256)-I-Ab complexes that were generated by the processing of M. tuberculosis Ag 85B in infected cells to both M. tuberculosis-specific T hybridoma cells and naïve P25 M. tuberculosis T-cell receptor (TCR)-transgenic T cells. In the presence of prefixed macrophages, exosomes from mycobacterium-infected macrophages provided weak stimulation to M. tuberculosis-specific T hybridoma cells but not naïve P25 T cells. Thus, infection with M. tuberculosis primes macrophages for the increased release of exosomes and microvesicles bearing M. tuberculosis peptide-MHC-II complexes that may generate antimicrobial T-cell responses. PMID:20837713

  10. Cyclophosphamide induces bone marrow to yield higher numbers of precursor dendritic cells in vitro capable of functional antigen presentation to T cells in vivo

    PubMed Central

    Salem, Mohamed L.; El-Naggar, Sabry A.; Cole, David J.

    2009-01-01

    We have shown recently that cyclophosphamide (CTX) treatment induced a marked increase in the numbers of immature dendritic cells (DCs) in blood, coinciding with enhanced antigen-specific responses of the adoptively transferred CD8+ T cells. Because this DC expansion was preceded by DC proliferation in bone marrow (BM), we tested whether BM post CTX treatment can generate higher numbers of functional DCs. BM was harvested three days after treatment of C57BL/6 mice with PBS or CTX and cultured with GM-CSF/IL-4 in vitro. Compared with control, BM from CTX-treated mice showed faster generation and yielded higher numbers of DCs with superior activation in response to toll-like receptor (TLR) agonists. Vaccination with peptide-pulsed DCs generated from BM from CTX-treated mice induced comparable adjuvant effects to those induced by control DCs. Taken together, post CTX BM harbors higher numbers of DC precursors capable of differentiating into functional DCs, which be targeted to create host microenvironment riches in activated DCs upon treatment with TLR agonists. PMID:20036354

  11. MiR-381-3p Regulates the Antigen-Presenting Capability of Dendritic Cells and Represses Antituberculosis Cellular Immune Responses by Targeting CD1c.

    PubMed

    Wen, Qian; Zhou, Chaoying; Xiong, Wenjing; Su, Jing; He, Jianchun; Zhang, Shimeng; Du, Xialin; Liu, Sudong; Wang, Juanjuan; Ma, Li

    2016-07-15

    Tuberculosis is still the widest spread infectious disease in the world, and more in-depth studies are needed on the interaction between the pathogen and the host. Due to the highest lipid components in Mycobacterium tuberculosis, the CD1 family that specifically presents antigenic lipids plays important roles in the antituberculosis immunity, especially CD1c, which functions as the intracellular Ag inspector at the full intracellular range. However, downregulation of the CD1c mRNA level has been observed in M. tuberculosis-infected cells, which is consistent with the regulatory mechanism of miRNA on gene expression. In this study, through combinatory analysis of previous miRNA transcriptomic assays and bioinformatic predictions by web-based algorithms, miR-381-3p was predicted to bind the 3'-untranslated region of CD1c gene. In vivo expression of miR-381-3p in dendritic cells (DCs) of TB patients is higher than in DCs of healthy individuals, inversely related to CD1c. Suppression of CD1c expression in bacillus Calmette-Guérin (BCG)-infected DCs was accompanied with upregulation of miR-381-3p, whereas inhibition of miR-381-3p could reverse suppression of CD1c expression and promote T cell responses against BCG infection. Further study indicated that miR-381-3p is also one of the mediators of the immune suppressor IL-10. Collectively, these results demonstrated the mechanism that suppression of CD1c by BCG infection is mediated by miR-381-3p. This finding may provide a novel approach to boost immune responses to M. tuberculosis. Copyright © 2016 by The American Association of Immunologists, Inc.

  12. Intestinal Antigen-Presenting Cells

    PubMed Central

    Flannigan, Kyle L.; Geem, Duke; Harusato, Akihito; Denning, Timothy L.

    2016-01-01

    The microbiota that populate the mammalian intestine are critical for proper host physiology, yet simultaneously pose a potential danger. Intestinal antigen-presenting cells, namely macrophages and dendritic cells (DCs), are integral components of the mucosal innate immune system that maintain co-existence with the microbiota in face of this constant threat. Intestinal macrophages and DCs integrate signals from the microenvironment to orchestrate innate and adaptive immune responses that ultimately lead to durable tolerance of the microbiota. Tolerance is not a default response, however, because macrophages and DCs remain poised to vigorously respond to pathogens that breach the epithelial barrier. In this review, we summarize the salient features of macrophages and DCs in the healthy and inflamed intestine and discuss how signals from the microbiota can influence their function. PMID:25976247

  13. Viewfoils for environmental capabilities presentation

    SciTech Connect

    1992-04-01

    This document contains information about the environmental applications of aerial surveys. It discusses the accuracy, dependability, history, advantages, and sensitivity of aerial surveys. Also included, are a brief overview of in-situ gamma spectroscopy and samples of aerial surveys. This document contains entirely of an outline and viewfoils for the presentation.

  14. Presentation of lipid antigens to T cells.

    PubMed

    Mori, Lucia; De Libero, Gennaro

    2008-04-15

    T cells specific for lipid antigens participate in regulation of the immune response during infections, tumor immunosurveillance, allergy and autoimmune diseases. T cells recognize lipid antigens as complexes formed with CD1 antigen-presenting molecules, thus resembling recognition of MHC-peptide complexes. The biophysical properties of lipids impose unique mechanisms for their delivery, internalization into antigen-presenting cells, membrane trafficking, processing, and loading of CD1 molecules. Each of these steps is controlled at molecular and celular levels and determines lipid immunogenicity. Lipid antigens may derive from microbes and from the cellular metabolism, thus allowing the immune system to survey a large repertoire of immunogenic molecules. Recognition of lipid antigens facilitates the detection of infectious agents and the initiation of responses involved in immunoregulation and autoimmunity. This review focuses on the presentation mechanisms and specific recognition of self and bacterial lipid antigens and discusses the important open issues.

  15. CD1 antigen presentation: how it works.

    PubMed

    Barral, Duarte C; Brenner, Michael B

    2007-12-01

    The classic concept of self-non-self discrimination by the immune system focused on the recognition of fragments from proteins presented by classical MHC molecules. However, the discovery of MHC-class-I-like CD1 antigen-presentation molecules now explains how the immune system also recognizes the abundant and diverse universe of lipid-containing antigens. The CD1 molecules bind and present amphipathic lipid antigens for recognition by T-cell receptors. Here, we outline the recent advances in our understanding of how the processes of CD1 assembly, trafficking, lipid-antigen binding and T-cell activation are achieved and the new insights into how lipid antigens differentially elicit CD1-restricted innate and adaptive T-cell responses.

  16. [Diagnostic capability of carcinoembryonic antigen elevation].

    PubMed

    Cerezo Ruiz, Antonio; Rosa Jiménez, Francisco; Lobón Hernández, José Antonio; Gómez Jiménez, Francisco Javier

    2014-12-01

    There is little information on the oncologic diagnostic accuracy of carcinoembryonic antigen (CEA) levels more than 3-fold above normal. To determine the prevalence of underlying cancer in patients with mild CEA elevation and the mean cost per patient of CEA determination. A retrospective study was carried out in all patients with CEA elevation (3-10 ng/ml) and suspicion of cancer referred to the gastroenterology or internal medicine outpatient units from 2001 to 2007. We studied 100 patients (60 men and 40 women), with a mean age of 67.4 ± 14.2 years and baseline CEA of 5.8 ± 1.7 ng/ml. The most important symptoms and signs were laboratory abnormalities (19 patients [19%]). Cancer was diagnosed in 4 patients (one gastric, 2 lung and one colon). Among patients without malignancies, 49 patients (49%) had no related processes, and 47 (47%) had benign diseases. During follow-up, one laryngeal cancer, one acute myeloid leukemia, and one colon cancer were detected (54.3 ± 24.6 months). We found no differences between baseline CEA levels in patients with and without cancer (6.6 ± 2.4 vs. 5.8 ± 1.7 ng/ml, p = 0.2). The mean cost per patient was 503.6 ± 257.6 €. Cancer was detected in a small proportion (7%) of patients with mild CEA elevation. The study of these patients is directly and indirectly associated with a not inconsiderable cost. Copyright © 2014 Elsevier España, S.L.U. and AEEH y AEG. All rights reserved.

  17. Antigen-Presenting Cells and Antigen Presentation in Tertiary Lymphoid Organs

    PubMed Central

    Hughes, Catherine E.; Benson, Robert A.; Bedaj, Marija; Maffia, Pasquale

    2016-01-01

    Tertiary lymphoid organs (TLOs) form in territorialized niches of peripheral tissues characterized by the presence of antigens; however, little is known about mechanism(s) of antigen handling by ectopic lymphoid structures. In this mini review, we will discuss the role of antigen-presenting cells and mechanisms of antigen presentation in TLOs, summarizing what is currently known about this facet of the formation and function of these tissues as well as identifying questions yet to be addressed. PMID:27872626

  18. Antigen cross-presentation of immune complexes.

    PubMed

    Platzer, Barbara; Stout, Madeleine; Fiebiger, Edda

    2014-01-01

    The ability of dendritic cells (DCs) to cross-present tumor antigens has long been a focus of interest to physicians, as well as basic scientists, that aim to establish efficient cell-based cancer immune therapy. A prerequisite for exploiting this pathway for therapeutic purposes is a better understanding of the mechanisms that underlie the induction of tumor-specific cytotoxic T-lymphocyte (CTL) responses when initiated by DCs via cross-presentation. The ability of humans DC to perform cross-presentation is of utmost interest, as this cell type is a main target for cell-based immunotherapy in humans. The outcome of a cross-presentation event is guided by the nature of the antigen, the form of antigen uptake, and the subpopulation of DCs that performs presentation. Generally, CD8α(+) DCs are considered to be the most potent cross-presenting DCs. This paradigm, however, only applies to soluble antigens. During adaptive immune responses, immune complexes form when antibodies interact with their specific epitopes on soluble antigens. Immunoglobulin G (IgG) immune complexes target Fc-gamma receptors on DCs to shuttle exogenous antigens efficiently into the cross-presentation pathway. This receptor-mediated cross-presentation pathway is a well-described route for the induction of strong CD8(+) T cell responses. IgG-mediated cross-presentation is intriguing because it permits the CD8(-) DCs, which are commonly considered to be weak cross-presenters, to efficiently cross-present. Engaging multiple DC subtypes for cross-presentation might be a superior strategy to boost CTL responses in vivo. We here summarize our current understanding of how DCs use IgG-complexed antigens for the efficient induction of CTL responses. Because of its importance for human cell therapy, we also review the recent advances in the characterization of cross-presentation properties of human DC subsets.

  19. Antigen Cross-Presentation of Immune Complexes

    PubMed Central

    Platzer, Barbara; Stout, Madeleine; Fiebiger, Edda

    2014-01-01

    The ability of dendritic cells (DCs) to cross-present tumor antigens has long been a focus of interest to physicians, as well as basic scientists, that aim to establish efficient cell-based cancer immune therapy. A prerequisite for exploiting this pathway for therapeutic purposes is a better understanding of the mechanisms that underlie the induction of tumor-specific cytotoxic T-lymphocyte (CTL) responses when initiated by DCs via cross-presentation. The ability of humans DC to perform cross-presentation is of utmost interest, as this cell type is a main target for cell-based immunotherapy in humans. The outcome of a cross-presentation event is guided by the nature of the antigen, the form of antigen uptake, and the subpopulation of DCs that performs presentation. Generally, CD8α+ DCs are considered to be the most potent cross-presenting DCs. This paradigm, however, only applies to soluble antigens. During adaptive immune responses, immune complexes form when antibodies interact with their specific epitopes on soluble antigens. Immunoglobulin G (IgG) immune complexes target Fc-gamma receptors on DCs to shuttle exogenous antigens efficiently into the cross-presentation pathway. This receptor-mediated cross-presentation pathway is a well-described route for the induction of strong CD8+ T cell responses. IgG-mediated cross-presentation is intriguing because it permits the CD8− DCs, which are commonly considered to be weak cross-presenters, to efficiently cross-present. Engaging multiple DC subtypes for cross-presentation might be a superior strategy to boost CTL responses in vivo. We here summarize our current understanding of how DCs use IgG-complexed antigens for the efficient induction of CTL responses. Because of its importance for human cell therapy, we also review the recent advances in the characterization of cross-presentation properties of human DC subsets. PMID:24744762

  20. Cyclosporine inhibits macrophage-mediated antigen presentation

    SciTech Connect

    Ziegler, H.K.; Palay, D.; Wentworth, P.; Cluff, C.

    1986-03-01

    The influence of cyclosporine on antigen-specific, macrophage-dependent T cell activation was analyzed in vitro. Murine T cell activation by antigens derived from Listeria monocytogenes was monitored by the production of interleukin-2. Pretreatment (2 hrs., 37/sup 0/C) of macrophages with cyclosporine resulted in a population of macrophages with a markedly diminished capacity to support the activation of T lymphocytes. When cyclosporine-pretreated macrophages were added to cultures of antigen and untreated T cells, the dose of cyclosporine which produced 50% inhibition was 1.5 ..mu..g/ml. Appropriate control experiments indicated that cyclosporine was indeed inhibiting at the macrophage level. The addition of interleukin-1 or indomethacin to the cultures did not alter the inhibitory effect of cyclosporine. Under conditions which produced >90% inhibition of antigen presentation, macrophage surface Ia expression was not altered, and the uptake and catabolism of radiolabelled antigen was normal. Thus, cyclosporine inhibits antigen presentation by a mechanism which appears unrelated to changes in Il-1 elaboration, prostaglandin production, Ia expression, or antigen uptake and catabolism.

  1. Mechanism of antigen presentation after hypertonic loading of soluble antigens

    PubMed Central

    Enders, Georg A

    2002-01-01

    Hypertonic loading of proteins into cells has been used to introduce soluble proteins into the major histocompatibility complex class I pathway of antigen presentation followed by cytotoxic T-lymphocyte (CTL) induction. The precise mechanism for this pathway is not completely understood. The antigen is either processed and presented by/on the same cell or by professional antigen-presenting cells (APC) after taking up the antigen from damaged or apoptotic cells. After loading labelled ovalbumin (OVA), it could be co-precipitated with the proteasome complex, supporting the role of this pathway for antigen processing. The processing speed however, appeared to be slow since intact OVA could be detected inside the cells even after 18 hr. This corresponded well with the processing of OVA by isolated proteasomes. On the other hand, enough peptides for recognition of target cells by CTLs were generated in this reaction. One reason for the low level of processing might be that hypertonic loading may damage the cells and inhibit direct processing. In fact, at least 50% of the cells became positive for Annexin V binding after hypertonic loading which indicates severe membrane alterations usually associated with the progress of apoptosis. Annexin V binds to phosphatidylserine residues which also serve as ligand for CD36 expressed on monocytes and some immature dendritic cells. This may direct the phagocytic pathway to hypertonically loaded cells and thus enable professional APCs to present OVA-peptides. Therefore, in addition to the direct processing of OVA, CTLs can be primed by professional APC after uptake of apoptotic, OVA-loaded cells. PMID:12153514

  2. Antigen Processing and Remodeling of the Endosomal Pathway: Requirements for Antigen Cross-Presentation

    PubMed Central

    Compeer, Ewoud Bernardus; Flinsenberg, Thijs Willem Hendrik; van der Grein, Susanna Geertje; Boes, Marianne

    2012-01-01

    Cross-presentation of endocytosed antigen as peptide/class I major histocompatibility complex complexes plays a central role in the elicitation of CD8+ T cell clones that mediate anti-viral and anti-tumor immune responses. While it has been clear that there are specific subsets of professional antigen presenting cells capable of antigen cross-presentation, identification of mechanisms involved is still ongoing. Especially amongst dendritic cells (DC), there are specialized subsets that are highly proficient at antigen cross-presentation. We here present a focused survey on the cell biological processes in the endosomal pathway that support antigen cross-presentation. This review highlights DC-intrinsic mechanisms that facilitate the cross-presentation of endocytosed antigen, including receptor-mediated uptake, maturation-induced endosomal sorting of membrane proteins, dynamic remodeling of endosomal structures and cell surface-directed endosomal trafficking. We will conclude with the description of pathogen-induced deviation of endosomal processing, and discuss how immune evasion strategies pertaining endosomal trafficking may preclude antigen cross-presentation. PMID:22566920

  3. Antigen processing and remodeling of the endosomal pathway: requirements for antigen cross-presentation.

    PubMed

    Compeer, Ewoud Bernardus; Flinsenberg, Thijs Willem Hendrik; van der Grein, Susanna Geertje; Boes, Marianne

    2012-01-01

    Cross-presentation of endocytosed antigen as peptide/class I major histocompatibility complex complexes plays a central role in the elicitation of CD8(+) T cell clones that mediate anti-viral and anti-tumor immune responses. While it has been clear that there are specific subsets of professional antigen presenting cells capable of antigen cross-presentation, identification of mechanisms involved is still ongoing. Especially amongst dendritic cells (DC), there are specialized subsets that are highly proficient at antigen cross-presentation. We here present a focused survey on the cell biological processes in the endosomal pathway that support antigen cross-presentation. This review highlights DC-intrinsic mechanisms that facilitate the cross-presentation of endocytosed antigen, including receptor-mediated uptake, maturation-induced endosomal sorting of membrane proteins, dynamic remodeling of endosomal structures and cell surface-directed endosomal trafficking. We will conclude with the description of pathogen-induced deviation of endosomal processing, and discuss how immune evasion strategies pertaining endosomal trafficking may preclude antigen cross-presentation.

  4. Antigen Presentation by MHC-Dressed Cells

    PubMed Central

    Nakayama, Masafumi

    2015-01-01

    Professional antigen-presenting cells (APCs) such as conventional dendritic cells (DCs) process protein antigens to MHC-bound peptides and then present the peptide–MHC complexes to T cells. In addition to this canonical antigen presentation pathway, recent studies have revealed that DCs and non-APCs can acquire MHC class I (MHCI) and/or MHC class II (MHCII) from neighboring cells through a process of cell–cell contact-dependent membrane transfer called trogocytosis. These MHC-dressed cells subsequently activate or regulate T cells via the preformed antigen peptide–MHC complexes without requiring any further processing. In addition to trogocytosis, intercellular transfer of MHCI and MHCII can be mediated by secretion of membrane vesicles such as exosomes from APCs, generating MHC-dressed cells. This review focuses on the physiological role of antigen presentation by MHCI- or MHCII-dressed cells, and also discusses differences and similarities between trogocytosis and exosome-mediated transfer of MHC. PMID:25601867

  5. Effect of present technology on airship capabilities

    NASA Technical Reports Server (NTRS)

    Madden, R. T.

    1975-01-01

    The effect is presented of updating past airship designs using current materials and propulsion systems to determine new airship performance and productivity capabilities. New materials and power plants permit reductions in the empty weights and increases in the useful load capabilities of past airship designs. The increased useful load capability results in increased productivity for a given range, i.e., either increased payload at the same operating speed or increased operating speed for the same payload weight or combinations of both. Estimated investment costs and operating costs are presented to indicate the significant cost parameters in estimating transportation costs of payloads in cents per ton mile. Investment costs are presented considering production lots of 1, 10 and 100 units. Operating costs are presented considering flight speeds and ranges.

  6. Methamphetamine inhibits antigen processing, presentation, and phagocytosis.

    PubMed

    Tallóczy, Zsolt; Martinez, Jose; Joset, Danielle; Ray, Yonaton; Gácser, Attila; Toussi, Sima; Mizushima, Noboru; Nosanchuk, Joshua D; Nosanchuk, Josh; Goldstein, Harris; Loike, John; Sulzer, David; Santambrogio, Laura

    2008-02-08

    Methamphetamine (Meth) is abused by over 35 million people worldwide. Chronic Meth abuse may be particularly devastating in individuals who engage in unprotected sex with multiple partners because it is associated with a 2-fold higher risk for obtaining HIV and associated secondary infections. We report the first specific evidence that Meth at pharmacological concentrations exerts a direct immunosuppressive effect on dendritic cells and macrophages. As a weak base, Meth collapses the pH gradient across acidic organelles, including lysosomes and associated autophagic organelles. This in turn inhibits receptor-mediated phagocytosis of antibody-coated particles, MHC class II antigen processing by the endosomal-lysosomal pathway, and antigen presentation to splenic T cells by dendritic cells. More importantly Meth facilitates intracellular replication and inhibits intracellular killing of Candida albicans and Cryptococcus neoformans, two major AIDS-related pathogens. Meth exerts previously unreported direct immunosuppressive effects that contribute to increased risk of infection and exacerbate AIDS pathology.

  7. Methamphetamine Inhibits Antigen Processing, Presentation, and Phagocytosis

    PubMed Central

    Joset, Danielle; Ray, Yonaton; Gácser, Attila; Toussi, Sima; Mizushima, Noboru; Nosanchuk, Josh; Goldstein, Harris; Loike, John; Sulzer, David; Santambrogio, Laura

    2008-01-01

    Methamphetamine (Meth) is abused by over 35 million people worldwide. Chronic Meth abuse may be particularly devastating in individuals who engage in unprotected sex with multiple partners because it is associated with a 2-fold higher risk for obtaining HIV and associated secondary infections. We report the first specific evidence that Meth at pharmacological concentrations exerts a direct immunosuppressive effect on dendritic cells and macrophages. As a weak base, Meth collapses the pH gradient across acidic organelles, including lysosomes and associated autophagic organelles. This in turn inhibits receptor-mediated phagocytosis of antibody-coated particles, MHC class II antigen processing by the endosomal–lysosomal pathway, and antigen presentation to splenic T cells by dendritic cells. More importantly Meth facilitates intracellular replication and inhibits intracellular killing of Candida albicans and Cryptococcus neoformans, two major AIDS-related pathogens. Meth exerts previously unreported direct immunosuppressive effects that contribute to increased risk of infection and exacerbate AIDS pathology. PMID:18282092

  8. Antigen-presenting capacity of rheumatoid synovial fibroblasts.

    PubMed Central

    Boots, A M; Wimmers-Bertens, A J; Rijnders, A W

    1994-01-01

    In normal, healthy joints, synovial fibroblasts do not express major histocompatibility complex (MHC) class II molecules. However, in inflamed joints of rheumatoid arthritis (RA) patients, synovial fibroblasts show an abundant expression of MHC class II. Does this increase in expression have functional consequences for antigen presentation to T cells? To date, the precise role of synovial fibroblasts in antigen presentation has not been documented. Here, we show by three different examples that cultured synovial fibroblasts with interferon-gamma (IFN-gamma)-induced MHC class II expression are capable of processing soluble protein for presentation to CD4+ T cells. First, the antigen-presenting cell (APC) function of synovial fibroblasts was studied in an autologous model. From synovial tissue of a RA patient both a fibroblast cell line and a tetanus toxoid (TT)-specific CD4+ T-cell line were generated. A dose-dependent TT response was observed only when TT was presented by IFN-gamma-pretreated synovial fibroblasts. As more direct evidence for MHC class II-restricted antigen presentation, the response of a Mycobacterium tuberculosis-specific CD4+ T-cell clone isolated from rheumatoid synovial fluid was demonstrated in the presence of synovial fibroblasts. The response was DR4Dw4-restricted and could be inhibited by monoclonal antibody (mAb) to HLA-DR. In addition, the lymphokine secretion pattern of the synovial T-cell clone did not differ qualitatively upon antigen-specific stimulation using peripheral blood mononuclear cells (PBMC) or synovial fibroblasts as APC. In order to provide evidence for intracellular antigen processing we next examined the response of a M. leprae-specific T-cell clone with known epitope specificity. Our data suggest that synovial fibroblasts are not passive bystanders, but can become active participants in the development and maintenance of chronic inflammation. PMID:7927499

  9. Antigen-Presenting Cells in the Skin.

    PubMed

    Kashem, Sakeen W; Haniffa, Muzlifah; Kaplan, Daniel H

    2017-02-06

    Professional antigen-presenting cells (APCs) in the skin include dendritic cells, monocytes, and macrophages. They are highly dynamic, with the capacity to enter skin from the peripheral circulation, patrol within tissue, and migrate through lymphatics to draining lymph nodes. Skin APCs are endowed with antigen sensing, processing, and presenting machinery and play key roles in initiating, modulating, and resolving cutaneous inflammation. Skin APCs are a highly heterogeneous population with functionally specialized subsets that are developmentally imprinted and modulated by local tissue microenvironmental and inflammatory cues. This review explores recent advances that have allowed for a more accurate taxonomy of APC subsets found in both mouse and human skin. It also examines the functional specificity of individual APC subsets and their collaboration with other immune cell types that together promote adaptive T cell and regional cutaneous immune responses during homeostasis, inflammation, and disease. Expected final online publication date for the Annual Review of Immunology Volume 35 is April 26, 2017 . Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  10. Instrument Pointing Capabilities: Past, Present, and Future

    NASA Technical Reports Server (NTRS)

    Blackmore, Lars; Murray, Emmanuell; Scharf, Daniel P.; Aung, Mimi; Bayard, David; Brugarolas, Paul; Hadaegh, Fred; Lee, Allan; Milman, Mark; Sirlin, Sam; hide

    2011-01-01

    This paper surveys the instrument pointing capabilities of past, present and future space telescopes and interferometers. As an important aspect of this survey, we present a taxonomy for "apples-to-apples" comparisons of pointing performances. First, pointing errors are defined relative to either an inertial frame or a celestial target. Pointing error can then be further sub-divided into DC, that is, steady state, and AC components. We refer to the magnitude of the DC error relative to the inertial frame as absolute pointing accuracy, and we refer to the magnitude of the DC error relative to a celestial target as relative pointing accuracy. The magnitude of the AC error is referred to as pointing stability. While an AC/DC partition is not new, we leverage previous work by some of the authors to quantitatively clarify and compare varying definitions of jitter and time window averages. With this taxonomy and for sixteen past, present, and future missions, pointing accuracies and stabilities, both required and achieved, are presented. In addition, we describe the attitude control technologies used to and, for future missions, planned to achieve these pointing performances.

  11. Instrument Pointing Capabilities: Past, Present, and Future

    NASA Technical Reports Server (NTRS)

    Blackmore, Lars; Murray, Emmanuell; Scharf, Daniel P.; Aung, Mimi; Bayard, David; Brugarolas, Paul; Hadaegh, Fred; Lee, Allan; Milman, Mark; Sirlin, Sam; Kang, Bryan

    2011-01-01

    This paper surveys the instrument pointing capabilities of past, present and future space telescopes and interferometers. As an important aspect of this survey, we present a taxonomy for "apples-to-apples" comparisons of pointing performances. First, pointing errors are defined relative to either an inertial frame or a celestial target. Pointing error can then be further sub-divided into DC, that is, steady state, and AC components. We refer to the magnitude of the DC error relative to the inertial frame as absolute pointing accuracy, and we refer to the magnitude of the DC error relative to a celestial target as relative pointing accuracy. The magnitude of the AC error is referred to as pointing stability. While an AC/DC partition is not new, we leverage previous work by some of the authors to quantitatively clarify and compare varying definitions of jitter and time window averages. With this taxonomy and for sixteen past, present, and future missions, pointing accuracies and stabilities, both required and achieved, are presented. In addition, we describe the attitude control technologies used to and, for future missions, planned to achieve these pointing performances.

  12. Antigen Export Reduces Antigen Presentation and Limits T Cell Control of M. tuberculosis.

    PubMed

    Srivastava, Smita; Grace, Patricia S; Ernst, Joel D

    2016-01-13

    Persistence of Mycobacterium tuberculosis results from bacterial strategies that manipulate host adaptive immune responses. Infected dendritic cells (DCs) transport M. tuberculosis to local lymph nodes but activate CD4 T cells poorly, suggesting bacterial manipulation of antigen presentation. However, M. tuberculosis antigens are also exported from infected DCs and taken up and presented by uninfected DCs, possibly overcoming this blockade of antigen presentation by infected cells. Here we show that the first stage of this antigen transfer, antigen export, benefits M. tuberculosis by diverting bacterial proteins from the antigen presentation pathway. Kinesin-2 is required for antigen export and depletion of this microtubule-based motor increases activation of antigen-specific CD4 T cells by infected cells and improves control of intracellular infection. Thus, although antigen transfer enables presentation by bystander cells, it does not compensate for reduced antigen presentation by infected cells and represents a bacterial strategy for CD4 T cell evasion.

  13. From the antigen-presenting cell to the antigen-presenting vesicle: the exosomes.

    PubMed

    Schartz, Noël Emile Célestin; Chaput, Nathalie; André, Fabrice; Zitvogel, Laurence

    2002-08-01

    Exosomes are membrane vesicles of 30 to 100 nm in diameter, of endocytic origin, and are produced and secreted in vitro by living cells of diverse origin. In vivo and in vitro experiments suggest, from their particular proteomic composition, that exosomes are involved in the transfer of tumor antigens to antigen presenting cells, and in the stimulation of a specific immune response. In this review, we provide a molecular characterization of exosomes. The hypotheses accounting for exosome biogenesis will be outlined. Finally, we will describe their bioactivities and discuss their potential relevance and clinical implementation for cancer immunotherapy.

  14. Isolation and In vivo Transfer of Antigen Presenting Cells

    PubMed Central

    Arora, Pooja; Kharkwal, Shalu Sharma; Porcelli, Steven A.

    2016-01-01

    Transfer of antigen presenting cells in vivo is a method used by immunologists to examine the potency of antigen presentation by a selected population of cells. This method is most commonly used to analyze presentation of protein antigens to MHC class I or II restricted T cells, but it can also be used for studies of nonconventional antigens such as CD1-presented lipids. In a recent study focusing on CD1d-restricted glycolipid antigen presentation to Natural Killer T cells, we compared antigen presenting properties of splenic B cells, CD8αPos dendritc cells (DCs) and CD8αNeg DCs (Arora et al., 2014). This protocol describes the detailed method used for isolation of these cell populations, and their transfer into recipient mice to analyze their antigen presenting properties. PMID:27390759

  15. Antigen presentation for priming T cells in central system.

    PubMed

    Dasgupta, Shaoni; Dasgupta, Subhajit

    2017-01-01

    Generation of myelin antigen-specific T cells is a major event in neuroimmune responses that causes demyelination. The antigen-priming of T cells and its location is important in chronic and acute inflammation. In autoimmune multiple sclerosis, the effector T cells are considered to generate in periphery. However, the reasons for chronic relapsing-remitting events are obscure. Considering mechanisms, a feasible aim of research is to investigate the role of antigen-primed T cells in lupus cerebritis. Last thirty years of investigations emphasize the relevance of microglia and infiltrated dendritic cells/macrophages as antigen presenting cells in the central nervous system. The recent approach towards circulating B-lymphocytes is an important area in the context. Here, we analyze the existing findings on antigen presentation in the central nervous system. The aim is to visualize signaling events of myelin antigen presentation to T cells and lead to the strategy of future goals on immunotherapy research.

  16. Antigenically Modified Human Pluripotent Stem Cells Generate Antigen-Presenting Dendritic Cells

    PubMed Central

    Zeng, Jieming; Wu, Chunxiao; Wang, Shu

    2015-01-01

    Human pluripotent stem cells (hPSCs) provide a promising platform to produce dendritic cell (DC) vaccine. To streamline the production process, we investigated a unique antigen-loading strategy that suits this novel platform. Specifically, we stably modified hPSCs using tumour antigen genes in the form of a full-length tumour antigen gene or an artificial tumour antigen epitope-coding minigene. Such antigenically modified hPSCs were able to differentiate into tumour antigen-presenting DCs. Without conventional antigen-loading, DCs derived from the minigene-modified hPSCs were ready to prime a tumour antigen-specific T cell response and further expand these specific T cells in restimulation processes. These expanded tumour antigen-specific T cells were potent effectors with central memory or effector memory phenotype. Thus, we demonstrated that immunocompetent tumour antigen-loaded DCs can be directly generated from antigenically modified hPSCs. Using such strategy, we can completely eliminate the conventional antigen-loading step and significantly simplify the production of DC vaccine from hPSCs. PMID:26471005

  17. MHC structure and function – antigen presentation. Part 1

    PubMed Central

    Goldberg, Anna Carla; Rizzo, Luiz Vicente

    2015-01-01

    The setting for the occurrence of an immune response is that of the need to cope with a vast array of different antigens from both pathogenic and non-pathogenic sources. When the first barriers against infection and innate defense fail, adaptive immune response enters the stage for recognition of the antigens by means of extremely variable molecules, namely immunoglobulins and T-cell receptors. The latter recognize the antigen exposed on cell surfaces, in the form of peptides presented by the HLA molecule. The first part of this review details the central role played by these molecules, establishing the close connection existing between their structure and their antigen presenting function. PMID:25807245

  18. Chemical biology of antigen presentation by MHC molecules.

    PubMed

    van Kasteren, Sander I; Overkleeft, Hermen; Ovaa, Huib; Neefjes, Jacques

    2014-02-01

    MHC class I and MHC class II molecules present peptides to the immune system to drive proper T cell responses. Pharmacological modulation of T-cell responses can offer treatment options for a range of immune-related diseases. Pharmacological downregulation of MHC molecules may find application in treatment of auto-immunity and transplantation rejection while pharmacological activation of antigen presentation would support immune responses to infection and cancer. Since the cell biology of MHC class I and MHC class II antigen presentation is understood in great detail, many potential targets for manipulation have been defined over the years. Here, we discuss how antigen presentation by MHC molecules can be modulated by pharmacological agents and how chemistry can further support the study of antigen presentation in general. The chemical biology of antigen presentation by MHC molecules shows surprising options for immune modulation and the development of future therapies. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. A Role For Mitochondria In Antigen Processing And Presentation.

    PubMed

    Bonifaz, Lc; Cervantes-Silva, Mp; Ontiveros-Dotor, E; López-Villegas, Eo; Sánchez-García, Fj

    2014-09-23

    Immune synapse formation is critical for T lymphocyte activation, and mitochondria have a role in this process, by localizing close to the immune synapse, regulating intracellular calcium concentration, and providing locally required ATP. The interaction between antigen presenting cells (APCs) and T lymphocytes is a two-way signaling process. However, the role of mitochondria in antigen presenting cells during this process remains unknown. For APCs to be able to activate T lymphocytes, they must first engage in an antigen-uptake, -processing, and -presentation process. Here we show that HEL-loaded B lymphocytes, as a type of APCs, undergo a small but significant mitochondrial depolarization by 1-2 h following antigen exposure thus suggesting an increase in their metabolic demands. Inhibition of ATP synthase (oligomycin) or mitochondrial Ca(2+) uniporter (MCU) (Ruthenium red) had no effect on antigen uptake. Therefore, antigen processing and antigen presentation were further analyzed. Oligomycin treatment reduced the amount of specific MHC-peptide complexes but not total MHC II on the cell membrane of B lymphocytes which correlated with a decrease in antigen presentation. However, oligomycin also reduced antigen presentation by B lymphocytes that endogenously express HEL and by B lymphocytes loaded with the HEL48-62 peptide, although to a lesser extent. ATP synthase inhibition and MCU inhibition had a clear inhibitory effect on antigen processing (DQ-OVA). Taking together these results suggest that ATP synthase and MCU are relevant for antigen processing and presentation. Finally, APCs mitochondria were found to re-organize towards the APC-T immune synapse. This article is protected by copyright. All rights reserved.

  20. The Role of Heat Shock Proteins in Antigen Cross Presentation

    PubMed Central

    Murshid, Ayesha; Gong, Jianlin; Calderwood, Stuart K.

    2012-01-01

    Heat shock proteins (HSPs) are molecular chaperones that bind tumor antigens and mediate their uptake into antigen presenting cells. HSP–antigen complexes are then directed toward either the MHC class I pathway through antigen cross presentation or the conventional class II pathway, leading to activation of T cell subsets. Uptake of HSP-chaperoned polypeptides can involve both receptor-mediated and receptor-independent routes, and mechanisms of antigen sorting between the Class I and II pathways after uptake are currently under investigation. The processes involved in internalization of HSP–antigen complexes differ somewhat from the mechanisms previously determined for (unchaperoned) particulate and free soluble antigens. A number of studies show that HSP-facilitated antigen cross presentation requires uptake of the complexes by scavenger receptors (SR) followed by processing in the proteasome, and loading onto MHC class I molecules. In this review we have examined the roles of HSPs and SR in antigen uptake, sorting, processing, cell signaling, and activation of innate and adaptive immunity. PMID:22566944

  1. B cell antigen extraction is regulated by physical properties of antigen-presenting cells

    PubMed Central

    2017-01-01

    Antibody production and affinity maturation are driven by B cell extraction and internalization of antigen from immune synapses. However, the extraction mechanism remains poorly understood. Here we develop DNA-based nanosensors to interrogate two previously proposed mechanisms, enzymatic liberation and mechanical force. Using antigens presented by either artificial substrates or live cells, we show that B cells primarily use force-dependent extraction and resort to enzymatic liberation only if mechanical forces fail to retrieve antigen. The use of mechanical forces renders antigen extraction sensitive to the physical properties of the presenting cells. We show that follicular dendritic cells are stiff cells that promote strong B cell pulling forces and stringent affinity discrimination. In contrast, dendritic cells are soft and promote acquisition of low-affinity antigens through low forces. Thus, the mechanical properties of B cell synapses regulate antigen extraction, suggesting that distinct properties of presenting cells support different stages of B cell responses. PMID:27923880

  2. Cathepsin S activity regulates antigen presentation and immunity.

    PubMed Central

    Riese, R J; Mitchell, R N; Villadangos, J A; Shi, G P; Palmer, J T; Karp, E R; De Sanctis, G T; Ploegh, H L; Chapman, H A

    1998-01-01

    MHC class II molecules display antigenic peptides on cell surfaces for recognition by CD4(+) T cells. Proteolysis is required in this process both for degradation of invariant chain (Ii) from class II-Ii complexes to allow subsequent binding of peptides, and for generation of the antigenic peptides. The cysteine endoprotease, cathepsin S, mediates Ii degradation in human and mouse antigen-presenting cells. Studies described here examine the functional significance of cathepsin S inhibition on antigen presentation and immunity. Specific inhibition of cathepsin S in A20 cells markedly impaired presentation of an ovalbumin epitope by interfering with class II-peptide binding, not by obstructing generation of the antigen. Administration of a cathepsin S inhibitor to mice in vivo selectively inhibited activity of cathepsin S in splenocytes, resulting in accumulation of a class II-associated Ii breakdown product, attenuation of class II-peptide complex formation, and inhibition of antigen presentation. Mice treated with inhibitor had an attenuated antibody response when immunized with ovalbumin but not the T cell-independent antigen TNP-Ficoll. In a mouse model of pulmonary hypersensitivity, treatment with the inhibitor also abrogated a rise in IgE titers and profoundly blocked eosinophilic infiltration in the lung. Thus, inhibition of cathepsin S in vivo alters Ii processing, antigen presentation, and immunity. These data identify selective inhibition of cysteine proteases as a potential therapeutic strategy for asthma and autoimmune disease processes. PMID:9616206

  3. Germinal center reaction: antigen affinity and presentation explain it all.

    PubMed

    Oropallo, Michael A; Cerutti, Andrea

    2014-07-01

    The selection and expansion of B cells undergoing affinity maturation in the germinal center is a hallmark of humoral immunity. A recent paper in Nature provides new insights into the relationships between the affinity of the immunoglobulin receptor for antigen, the ability of B cells to present antigen to T cells, and the processes of selection, mutation, and clonal expansion in the germinal center.

  4. A role for mitochondria in antigen processing and presentation

    PubMed Central

    Bonifaz, Laura C; Cervantes-Silva, Mariana P; Ontiveros-Dotor, Elizabeth; López-Villegas, Edgar O; Sánchez-García, F Javier

    2015-01-01

    Immune synapse formation is critical for T-lymphocyte activation, and mitochondria have a role in this process, by localizing close to the immune synapse, regulating intracellular calcium concentration, and providing locally required ATP. The interaction between antigen-presenting cells (APCs) and T lymphocytes is a two-way signalling process. However, the role of mitochondria in APCs during this process remains unknown. For APCs to be able to activate T lymphocytes, they must first engage in an antigen-uptake, -processing and -presentation process. Here we show that hen egg white lysozyme (HEL) -loaded B lymphocytes, as a type of APC, undergo a small but significant mitochondrial depolarization by 1–2 hr following antigen exposure, suggesting an increase in their metabolic demands. Inhibition of ATP synthase (oligomycin) or mitochondrial Ca2+ uniporter (MCU) (Ruthenium red) had no effect on antigen uptake. Therefore, antigen processing and antigen presentation were further analysed. Oligomycin treatment reduced the amount of specific MHC–peptide complexes but not total MHC II on the cell membrane of B lymphocytes, which correlated with a decrease in antigen presentation. However, oligomycin also reduced antigen presentation by B lymphocytes, which endogenously express HEL and by B lymphocytes loaded with the HEL48–62 peptide, although to a lesser extent. ATP synthase inhibition and MCU inhibition had a clear inhibitory effect on antigen processing (DQ-OVA). Taken together these results suggest that ATP synthase and MCU are relevant for antigen processing and presentation. Finally, APC mitochondria were found to re-organize towards the APC–T immune synapse. PMID:25251370

  5. Modes of Antigen Presentation by Lymph Node Stromal Cells and Their Immunological Implications.

    PubMed

    Hirosue, Sachiko; Dubrot, Juan

    2015-01-01

    Antigen presentation is no longer the exclusive domain of cells of hematopoietic origin. Recent works have demonstrated that lymph node stromal cell (LNSC) populations, such as fibroblastic reticular cells, lymphatic and blood endothelial cells, not only provide a scaffold for lymphocyte interactions but also exhibit active immunomodulatory roles that are critical to mounting and resolving effective immune responses. Importantly, LNSCs possess the ability to present antigens and establish antigen-specific interactions with T cells. One example is the expression of peripheral tissue antigens, which are presented on major histocompatibility complex (MHC)-I molecules with tolerogenic consequences on T cells. Additionally, exogenous antigens, including self and tumor antigens, can be processed and presented on MHC-I complexes, which result in dysfunctional activation of antigen-specific CD8(+) T cells. While MHC-I is widely expressed on cells of both hematopoietic and non-hematopoietic origins, antigen presentation via MHC-II is more precisely regulated. Nevertheless, LNSCs are capable of endogenously expressing, or alternatively, acquiring MHC-II molecules. Transfer of antigen between LNSC and dendritic cells in both directions has been recently suggested to promote tolerogenic roles of LNSCs on the CD4(+) T cell compartment. Thus, antigen presentation by LNSCs is thought to be a mechanism that promotes the maintenance of peripheral tolerance as well as generates a pool of diverse antigen-experienced T cells for protective immunity. This review aims to integrate the current and emerging literature to highlight the importance of LNSCs in immune responses, and emphasize their role in antigen trafficking, retention, and presentation.

  6. The Cellular Redox Environment Alters Antigen Presentation*

    PubMed Central

    Trujillo, Jonathan A.; Croft, Nathan P.; Dudek, Nadine L.; Channappanavar, Rudragouda; Theodossis, Alex; Webb, Andrew I.; Dunstone, Michelle A.; Illing, Patricia T.; Butler, Noah S.; Fett, Craig; Tscharke, David C.; Rossjohn, Jamie; Perlman, Stanley; Purcell, Anthony W.

    2014-01-01

    Cysteine-containing peptides represent an important class of T cell epitopes, yet their prevalence remains underestimated. We have established and interrogated a database of around 70,000 naturally processed MHC-bound peptides and demonstrate that cysteine-containing peptides are presented on the surface of cells in an MHC allomorph-dependent manner and comprise on average 5–10% of the immunopeptidome. A significant proportion of these peptides are oxidatively modified, most commonly through covalent linkage with the antioxidant glutathione. Unlike some of the previously reported cysteine-based modifications, this represents a true physiological alteration of cysteine residues. Furthermore, our results suggest that alterations in the cellular redox state induced by viral infection are communicated to the immune system through the presentation of S-glutathionylated viral peptides, resulting in altered T cell recognition. Our data provide a structural basis for how the glutathione modification alters recognition by virus-specific T cells. Collectively, these results suggest that oxidative stress represents a mechanism for modulating the virus-specific T cell response. PMID:25135637

  7. Self-Antigen Presentation by Dendritic Cells in Autoimmunity

    PubMed Central

    Hopp, Ann-Katrin; Rupp, Anne; Lukacs-Kornek, Veronika

    2014-01-01

    The operation of both central and peripheral tolerance ensures the prevention of autoimmune diseases. The maintenance of peripheral tolerance requires self-antigen presentation by professional antigen presenting cells (APCs). Dendritic cells (DCs) are considered as major APCs involved in this process. The current review discusses the role of DCs in autoimmune diseases, the various factors involved in the induction and maintenance of tolerogenic DC phenotype, and pinpoints their therapeutic capacity as well as potential novel targets for future clinical studies. PMID:24592266

  8. Ceramide Inhibits Antigen Uptake and Presentation by Dendritic Cells

    PubMed Central

    Sallusto, Federica; Nicolò, Chiara; De Maria, Ruggero; Corinti, Silvia; Testi, Roberto

    1996-01-01

    Ceramides are intramembrane diffusible mediators involved in transducing signals originated from a variety of cell surface receptors. Different adaptive and differentiative cellular responses, including apoptotic cell death, use ceramide-mediated pathways as an essential part of the program. Here, we show that human dendritic cells respond to CD40 ligand, as well as to tumor necrosis factor-α and IL-1β, with intracellular ceramide accumulation, as they are induced to differentiate. Dendritic cells down-modulate their capacity to take up soluble antigens in response to exogenously added or endogenously produced ceramides. This is followed by an impairment in presenting soluble antigens to specific T cell clones, while cell viability and the capacity to stimulate allogeneic responses or to present immunogenic peptides is fully preserved. Thus, ceramide-mediated pathways initiated by different cytokines can actively modulate professional antigen-presenting cell function and antigen-specific immune responses. PMID:8976196

  9. Kinetics of Antigen Expression and Epitope Presentation during Virus Infection

    PubMed Central

    Croft, Nathan P.; Smith, Stewart A.; Wong, Yik Chun; Tan, Chor Teck; Dudek, Nadine L.; Flesch, Inge E. A.; Lin, Leon C. W.; Tscharke, David C.; Purcell, Anthony W.

    2013-01-01

    Current knowledge about the dynamics of antigen presentation to T cells during viral infection is very poor despite being of fundamental importance to our understanding of anti-viral immunity. Here we use an advanced mass spectrometry method to simultaneously quantify the presentation of eight vaccinia virus peptide-MHC complexes (epitopes) on infected cells and the amounts of their source antigens at multiple times after infection. The results show a startling 1000-fold range in abundance as well as strikingly different kinetics across the epitopes monitored. The tight correlation between onset of protein expression and epitope display for most antigens provides the strongest support to date that antigen presentation is largely linked to translation and not later degradation of antigens. Finally, we show a complete disconnect between the epitope abundance and immunodominance hierarchy of these eight epitopes. This study highlights the complexity of viral antigen presentation by the host and demonstrates the weakness of simple models that assume total protein levels are directly linked to epitope presentation and immunogenicity. PMID:23382674

  10. Lipid peroxidation causes endosomal antigen release for cross-presentation

    PubMed Central

    Dingjan, Ilse; Verboogen, Daniëlle RJ; Paardekooper, Laurent M; Revelo, Natalia H; Sittig, Simone P; Visser, Linda J; Mollard, Gabriele Fischer von; Henriet, Stefanie SV; Figdor, Carl G; ter Beest, Martin; van den Bogaart, Geert

    2016-01-01

    Dendritic cells (DCs) present foreign antigen in major histocompatibility complex (MHC) class I molecules to cytotoxic T cells in a process called cross-presentation. An important step in this process is the release of antigen from the lumen of endosomes into the cytosol, but the mechanism of this step is still unclear. In this study, we show that reactive oxygen species (ROS) produced by the NADPH-oxidase complex NOX2 cause lipid peroxidation, a membrane disrupting chain-reaction, which in turn results in antigen leakage from endosomes. Antigen leakage and cross-presentation were inhibited by blocking ROS production or scavenging radicals and induced when using a ROS-generating photosensitizer. Endosomal antigen release was impaired in DCs from chronic granulomatous disease (CGD) patients with dysfunctional NOX2. Thus, NOX2 induces antigen release from endosomes for cross-presentation by direct oxidation of endosomal lipids. This constitutes a new cellular function for ROS in regulating immune responses against pathogens and cancer. PMID:26907999

  11. Lipid peroxidation causes endosomal antigen release for cross-presentation.

    PubMed

    Dingjan, Ilse; Verboogen, Daniëlle Rj; Paardekooper, Laurent M; Revelo, Natalia H; Sittig, Simone P; Visser, Linda J; Mollard, Gabriele Fischer von; Henriet, Stefanie Sv; Figdor, Carl G; Ter Beest, Martin; van den Bogaart, Geert

    2016-02-24

    Dendritic cells (DCs) present foreign antigen in major histocompatibility complex (MHC) class I molecules to cytotoxic T cells in a process called cross-presentation. An important step in this process is the release of antigen from the lumen of endosomes into the cytosol, but the mechanism of this step is still unclear. In this study, we show that reactive oxygen species (ROS) produced by the NADPH-oxidase complex NOX2 cause lipid peroxidation, a membrane disrupting chain-reaction, which in turn results in antigen leakage from endosomes. Antigen leakage and cross-presentation were inhibited by blocking ROS production or scavenging radicals and induced when using a ROS-generating photosensitizer. Endosomal antigen release was impaired in DCs from chronic granulomatous disease (CGD) patients with dysfunctional NOX2. Thus, NOX2 induces antigen release from endosomes for cross-presentation by direct oxidation of endosomal lipids. This constitutes a new cellular function for ROS in regulating immune responses against pathogens and cancer.

  12. Central Tolerance to Tissue-specific Antigens Mediated by Direct and Indirect Antigen Presentation

    PubMed Central

    Gallegos, Alena M.; Bevan, Michael J.

    2004-01-01

    Intrathymic expression of tissue-specific antigens (TSAs) by medullary thymic epithelial cells (Mtecs) leads to deletion of autoreactive T cells. However, because Mtecs are known to be poor antigen-presenting cells (APCs) for tolerance to ubiquitous antigens, and very few Mtecs express a given TSA, it was unclear if central tolerance to TSA was induced directly by Mtec antigen presentation or indirectly by thymic bone marrow (BM)-derived cells via cross-presentation. We show that professional BM-derived APCs acquire TSAs from Mtecs and delete autoreactive CD8 and CD4 T cells. Although direct antigen presentation by Mtecs did not delete the CD4 T cell population tested in this study, Mtec presentation efficiently deleted both monoclonal and polyclonal populations of CD8 T cells. For developing CD8 T cells, deletion by BM-derived APC and by Mtec presentation occurred abruptly at the transitional, CD4high CD8low TCRintermediate stage, presumably as the cells transit from the cortex to the medulla. These studies reveal a cooperative relationship between Mtecs and BM-derived cells in thymic elimination of autoreactive T cells. Although Mtecs synthesize TSAs and delete a subset of autoreactive T cells, BM-derived cells extend the range of clonal deletion by cross-presenting antigen captured from Mtecs. PMID:15492126

  13. Viral immune evasion: Lessons in MHC class I antigen presentation.

    PubMed

    van de Weijer, Michael L; Luteijn, Rutger D; Wiertz, Emmanuel J H J

    2015-03-01

    The MHC class I antigen presentation pathway enables cells infected with intracellular pathogens to signal the presence of the invader to the immune system. Cytotoxic T lymphocytes are able to eliminate the infected cells through recognition of pathogen-derived peptides presented by MHC class I molecules at the cell surface. In the course of evolution, many viruses have acquired inhibitors that target essential stages of the MHC class I antigen presentation pathway. Studies on these immune evasion proteins reveal fascinating strategies used by viruses to elude the immune system. Viral immunoevasins also constitute great research tools that facilitate functional studies on the MHC class I antigen presentation pathway, allowing the investigation of less well understood routes, such as TAP-independent antigen presentation and cross-presentation of exogenous proteins. Viral immunoevasins have also helped to unravel more general cellular processes. For instance, basic principles of ER-associated protein degradation via the ubiquitin-proteasome pathway have been resolved using virus-induced degradation of MHC class I as a model. This review highlights how viral immunoevasins have increased our understanding of MHC class I-restricted antigen presentation.

  14. Two genetically identical antigen-presenting cell clones display heterogeneity in antigen processing.

    PubMed Central

    Michalek, M T; Benacerraf, B; Rock, K L

    1989-01-01

    Evidence from various antigen systems suggests that antigen processing can be one factor that determines the repertoire of immunogenic peptides. Thus, processing events may account for some of the disparity between the available and expressed helper T-cell repertoires. In this report, we demonstrate that the immunodominant T-cell determinant in ovalbumin [p323-339; ovalbumin-(323-339) heptadecapeptide] is processed differently by two genetically identical antigen-presenting cell lines, M12 and A20. The ovalbumin-specific T-cell-T-cell hybridomas, DO-11.10 and 3DO-54.8, were used to detect processed antigen. These T-T hybridomas have different fine specificities for the p323-339 determinant. A20 cells presented native ovalbumin well to both T-T hybridomas, whereas M12 cells presented native ovalbumin well to 3DO-54.8 but very inefficiently to DO-11.10. M12 and A20 cells effectively stimulated both T-T hybridomas with the same concentrations of the immunogenic synthetic peptide p323-339. Therefore, M12 cells and DO-11.10 can interact with each other, and both T-T hybridomas have similar sensitivities for the same immunogenic peptide. We conclude that genetically identical antigen-presenting cells can display heterogeneity in the fine processing of an immunodominant T-cell determinant, and synthetic model peptides that represent the minimal stimulatory sequence of a T-cell determinant are not necessarily identical to the structure of in vivo processed antigen. Heterogeneity in antigen processing by individual antigen-presenting cells would serve to increase the repertoire of immunogenic peptides that are presented to T cells. PMID:2470101

  15. Antigen presentation by monocytes and monocyte-derived cells.

    PubMed

    Randolph, Gwendalyn J; Jakubzick, Claudia; Qu, Chunfeng

    2008-02-01

    Monocytes are circulating mononuclear phagocytes with a fundamental capacity to differentiate into macrophages. This differentiation can, in the presence of the right environmental cues, be re-directed instead to dendritic cells (DCs). Recent advances have been made in understanding the role of monocytes and their derivatives in presenting antigen to drive immune responses, and we review this topic herein. We briefly discuss the heterogeneity of monocytes in the blood and subsequently raise the possibility that one of the major monocyte phenotypes in the blood corresponds with a population of 'blood DCs' previously proposed to drive T-independent antibody reactions in the spleen. Then we evaluate the role of monocytes in T-dependent immunity, considering their role in acquiring antigens for presentation before exiting the bloodstream and their ability to differentiate into macrophages versus antigen-presenting DCs. Finally, we review recent literature on the role of monocyte-derived cells in cross-presentation and discuss the possibility that monocyte-derived cells participate critically in processing antigen for cross-priming, even if they do not present that antigen to T cells themselves.

  16. Neutrophils acquire the capacity for antigen presentation to memory CD4(+) T cells in vitro and ex vivo.

    PubMed

    Vono, Maria; Lin, Ang; Norrby-Teglund, Anna; Koup, Richard A; Liang, Frank; Loré, Karin

    2017-04-06

    Neutrophils are critical cells of the innate immune system and rapidly respond to tissue injury and infection. Increasing evidence also indicates that neutrophils have versatile functions in contributing to adaptive immunity by internalizing and transporting antigen and influencing antigen-specific responses. Here, we demonstrate that freshly isolated human neutrophils can function as antigen-presenting cells (APCs) to memory CD4(+) T cells. Neutrophils pulsed with the cognate antigens cytomegalovirus pp65 or influenza hemagglutinin were able to present the antigens to autologous antigen-specific CD4(+) T cells in a major histocompatibility complex class II (MHC-II; HLA-DR)-dependent manner. Although myeloid dendritic cells and monocytes showed superior presenting ability, neutrophils consistently displayed antigen presentation capability. Upregulation of HLA-DR on neutrophils required the presence of the antigen-specific or activated T cells whereas exposure to innate stimuli such as Toll-like receptor ligands was not sufficient. Neutrophils sorted from vaccine-draining lymph nodes from rhesus macaques also showed expression of HLA-DR and were capable of presenting vaccine antigen to autologous antigen-specific memory CD4(+) T cells ex vivo. Altogether, the data demonstrate that neutrophils can adapt a function as APCs and, in combination with their abundance in the immune system, may have a significant role in regulating antigen-specific T-cell responses.

  17. MHC structure and function − antigen presentation. Part 2

    PubMed Central

    Goldberg, Anna Carla; Rizzo, Luiz Vicente

    2015-01-01

    The second part of this review deals with the molecules and processes involved in the processing and presentation of the antigenic fragments to the T-cell receptor. Though the nature of the antigens presented varies, the most significant class of antigens is proteins, processed within the cell to be then recognized in the form of peptides, a mechanism that confers an extraordinary degree of precision to this mode of immune response. The efficiency and accuracy of this system is also the result of the myriad of mechanisms involved in the processing of proteins and production of peptides, in addition to the capture and recycling of alternative sources aiming to generate further diversity in the presentation to T-cells. PMID:25807243

  18. Comparative Analysis of Gingival Tissue Antigen Presentation Pathways in Aging and Periodontitis

    PubMed Central

    Gonzalez, O.A.; Novak, M.J.; Kirakodu, S.; Orraca, L.; Chen, K.C.; Strom-berg, A.; Gonzalez-Martinez, J.; Ebersole, J. L.

    2014-01-01

    Aim Gingival tissues of periodontitis lesions contribute to local elevations in mediators, including both specific T cell and antibody immune responses to oral bacterial antigens. Thus, antigen processing and presentation activities must exist in these tissues to link antigen-presenting cells with adaptive immunity. We hypothesized that alterations in the transcriptome of antigen processing and presentation genes occur in aging gingival tissues and that periodontitis enhances these differences reflecting tissues less capable of immune resistance to oral pathogens. Materials and Methods Rhesus monkeys (n=34) from 3–23 years of age were examined. A buccal gingival sample from healthy or periodontitis sites were obtained, total RNA isolated, and microarray analysis was used to describe the transcriptome. Results The results demonstrated increased transcription of genes related to the MHC class II and negative regulation of NK cells with aging in healthy gingival tissues. In contrast, both adult and aging periodontitis tissues showed decreased transcription of genes for MHC class II antigens, coincident with up-regulation of MHC class I-associated genes. Conclusion These transcriptional changes suggest a response of healthy aging tissues through the class II pathway (i.e., endocytosed antigens) and altered responses in periodontitis that could reflect host-associated self-antigens or targeting cytosolic intra-cellular microbial pathogens. PMID:24304139

  19. HLA class II antigen presentation by prostate cancer cells.

    PubMed

    Younger, A R; Amria, S; Jeffrey, W A; Mahdy, A E M; Goldstein, O G; Norris, J S; Haque, A

    2008-01-01

    Prostate cancer is the second most commonly diagnosed cancer in men. Recent evidence suggests that reduced expression of target protein antigens and human leukocyte antigen (HLA) molecules is the predominant immune escape mechanism of malignant prostate tumor cells. The purpose of this study was to investigate the prospect of antigen specific immunotherapy against prostate cancer via the HLA class II pathway of immune recognition. Here, we show for the first time that prostate cancer cells express HLA class II proteins that are recognized by CD4+ T cells. Prostate tumor cells transduced with class II molecules efficiently presented tumor-associated antigens/peptides to CD4+ T cells. This data suggests that malignant prostate tumors can be targeted via the HLA class II pathway, and that class II-positive tumors could be employed for direct antigen presentation, and CD4+ T-cell mediated tumor immunotherapy.Prostate Cancer and Prostatic Diseases (2008) 11, 334-341; doi:10.1038/sj.pcan.4501021; published online 16 October 2007.

  20. Modulation of Ia and photoreactive antigen on antigen-presenting cells: fun with a photoprobe.

    PubMed

    Thomas, D W; Eades, L; Wilson, C; Solvay, M J

    1985-12-01

    To identify the antigen-specific recognition complex containing elements from T cells and antigen-presenting cells (APC), a photoactivatable antigen system was developed which could potentially crosslink the complex during the specific cellular responses. In this paper we describe the development of this system using murine T-cell hybridomas responding to stimulator cells chemically conjugated with N-hydroxysuccinimidyl 4-azidobenzoate (HSAB) and genetically restricted by I-Ad. In initial experiments it was found that several I-Ad-positive B-cell lines were nonstimulatory when coupled with HSAB, but that I-Ad-positive P388D1 macrophage-like cells were efficient stimulators of HSAB-specific T-cell responses. These results suggested that the relevant HSAB coupled surface structure was not likely I-Ad. To substantiate this point, Ia-positive or Ia-negative P388D1 cells were initially coupled with HSAB and the expression of Ia was modulated by the addition and withdrawal of Con A-stimulated spleen cell supernatant fluid through several days of culture. Under these conditions, efficient stimulation was only observed when Ia was expressed, although the HSAB antigen was continuously present. In other experiments it was found that exposure of HSAB-coupled APC to light selectively eliminated their stimulatory capacity for HSAB-specific T hybridomas, suggesting that the light-induced crosslinking by HSAB directly eliminates the antigenic determinant. This antigen system allows a unique opportunity to manipulate the antigen during specific cellular interactions, and to introduce covalent crosslinking of the specific antigen recognition complex that may allow its isolation and characterization.

  1. Activated Brain Endothelial Cells Cross-Present Malaria Antigen.

    PubMed

    Howland, Shanshan W; Poh, Chek Meng; Rénia, Laurent

    2015-06-01

    In the murine model of cerebral malaria caused by P. berghei ANKA (PbA), parasite-specific CD8+ T cells directly induce pathology and have long been hypothesized to kill brain endothelial cells that have internalized PbA antigen. We previously reported that brain microvessel fragments from infected mice cross-present PbA epitopes, using reporter cells transduced with epitope-specific T cell receptors. Here, we confirm that endothelial cells are the population responsible for cross-presentation in vivo, not pericytes or microglia. PbA antigen cross-presentation by primary brain endothelial cells in vitro confers susceptibility to killing by CD8+ T cells from infected mice. IFNγ stimulation is required for brain endothelial cross-presentation in vivo and in vitro, which occurs by a proteasome- and TAP-dependent mechanism. Parasite strains that do not induce cerebral malaria were phagocytosed and cross-presented less efficiently than PbA in vitro. The main source of antigen appears to be free merozoites, which were avidly phagocytosed. A human brain endothelial cell line also phagocytosed P. falciparum merozoites. Besides being the first demonstration of cross-presentation by brain endothelial cells, our results suggest that interfering with merozoite phagocytosis or antigen processing may be effective strategies for cerebral malaria intervention.

  2. Mice completely lacking immunoproteasomes display major alterations in antigen presentation

    PubMed Central

    Kincaid, Eleanor Z; Che, Jenny W; York, Ian; Escobar, Hernando; Reyes-Vargas, Eduardo; Delgado, Julio C.; Welsh, Raymond M; Karow, Margaret L.; Murphy, Andrew J.; Valenzuela, David M.; Yancopoulos, George D.; Rock, Kenneth L

    2011-01-01

    The importance of immunoproteasomes to antigen presentation has been unclear because animals totally lacking immunoproteasomes have not been previously developed. Here we show that dendritic cells from mice lacking the three immunoproteasome catalytic subunits display defects in presenting multiple major histocompatability (MHC) class I epitopes. During viral infection in vivo, the presentation of a majority of MHC class I epitopes is markedly reduced in immunoproteasome-deficient animals, while presentation of MHC class II peptides is unaffected. By mass spectrometry the repertoire of MHC class I-presented peptides is ~50% different and these differences are sufficient to stimulate robust transplant rejection of wild type cells in mutant mice. These results indicate that immunoproteasomes play a much more important role in antigen presentation than previously thought. PMID:22197977

  3. Nanoscale artificial antigen presenting cells for T cell immunotherapy.

    PubMed

    Perica, Karlo; De León Medero, Andrés; Durai, Malarvizhi; Chiu, Yen Ling; Bieler, Joan Glick; Sibener, Leah; Niemöller, Michaela; Assenmacher, Mario; Richter, Anne; Edidin, Michael; Oelke, Mathias; Schneck, Jonathan

    2014-01-01

    Artificial antigen presenting cells (aAPC), which deliver stimulatory signals to cytotoxic lymphocytes, are a powerful tool for both adoptive and active immunotherapy. Thus far, aAPC have been synthesized by coupling T cell activating proteins such as CD3 or MHC-peptide to micron-sized beads. Nanoscale platforms have different trafficking and biophysical interaction properties and may allow development of new immunotherapeutic strategies. We therefore manufactured aAPC based on two types of nanoscale particle platforms: biocompatible iron-dextran paramagnetic particles (50-100 nm in diameter) and avidin-coated quantum dot nanocrystals (~30 nm). Nanoscale aAPC induced antigen-specific T cell proliferation from mouse splenocytes and human peripheral blood T cells. When injected in vivo, both iron-dextran particles and quantum dot nanocrystals enhanced tumor rejection in a subcutaneous mouse melanoma model. This is the first description of nanoscale aAPC that induce antigen-specific T cell proliferation in vitro and lead to effective T cell stimulation and inhibition of tumor growth in vivo. Artifical antigen presenting cells could revolutionize the field of cancer-directed immunotherapy. This team of investigators have manufactured two types of nanoscale particle platform-based aAPCs and demonstrates that both iron-dextran particles and quantum dot nanocrystals enhance tumor rejection in a melanoma model, providing the first description of nanoscale aAPCs that lead to effective T cell stimulation and inhibition of tumor growth. © 2013.

  4. Advanced Telescopes and Observatories Capability Roadmap Presentation to the NRC

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This viewgraph presentation provides an overview of the NASA Advanced Planning and Integration Office (APIO) roadmap for developing technological capabilities for telescopes and observatories in the following areas: Optics; Wavefront Sensing and Control and Interferometry; Distributed and Advanced Spacecraft; Large Precision Structures; Cryogenic and Thermal Control Systems; Infrastructure.

  5. Tumour immunogenicity, antigen presentation and immunological barriers in cancer immunotherapy

    PubMed Central

    Escors, David

    2014-01-01

    Since the beginning of the 20th century, scientists have tried to stimulate the anti-tumour activities of the immune system to fight against cancer. However, the scientific effort devoted on the development of cancer immunotherapy has not been translated into the expected clinical success. On the contrary, classical anti-neoplastic treatments such as surgery, radiotherapy and chemotherapy are the first line of treatment. Nevertheless, there is compelling evidence on the immunogenicity of cancer cells, and the capacity of the immune system to expand cancer-specific effector cytotoxic T cells. However, the effective activation of anti-cancer T cell responses strongly depends on efficient tumour antigen presentation from professional antigen presenting cells such as dendritic cells (DCs). Several strategies have been used to boost DC antigen presenting functions, but at the end cancer immunotherapy is not as effective as would be expected according to preclinical models. In this review we comment on these discrepancies, focusing our attention on the contribution of regulatory T cells and myeloid-derived suppressor cells to the lack of therapeutic success of DC-based cancer immunotherapy. PMID:24634791

  6. Antigen processing and presentation: evolution from a bird's eye view.

    PubMed

    Kaufman, Jim

    2013-09-01

    Most detailed knowledge of the MHC outside of mammals has come from studies of chickens, originally due to the economic importance of the poultry industry. We have used our discoveries about the chicken MHC to develop a framework for understanding the evolution of the MHC, based on the importance of genomic organisation for gene co-evolution. In humans, MHC class I molecules are polymorphic and determine the specificity of peptide presentation, while the molecules involved in antigen processing are functionally monomorphic. The genes for tapasin, transporters associated with antigen presentation (TAPs) and inducible proteasome components (LMPs) are located in and beyond the class II region, far away from the class I genes in the class I region. In contrast, chickens express only one class I locus at high levels, which can result in strong MHC associations with resistance to particular infectious pathogens. The chicken TAP and tapasin genes are located very close to the class I genes, and have high levels of allelic polymorphism and moderate sequence diversity, co-evolving their specificities to work optimally with the dominantly expressed class I molecule. The salient features of the chicken MHC are found in many if not most non-mammalian species examined, and are likely to represent the ancestral organisation of the MHC. Comparison with the MHC organisation of humans and typical mammals suggests that a large inversion brought the class III region into the middle of the MHC, separating the antigen processing genes from the class I gene, breaking the co-evolutionary relationships and allowing a multigene family of well-expressed class I genes. Such co-evolution in the primordial MHC was likely responsible for the appearance of the antigen presentation pathways and receptor-ligand interactions at the birth of the adaptive immune system. Of course, much further work is required to understand this evolutionary framework in more detail.

  7. Serine Proteases Enhance Immunogenic Antigen Presentation on Lung Cancer Cells.

    PubMed

    Peters, Haley L; Tripathi, Satyendra C; Kerros, Celine; Katayama, Hiroyuki; Garber, Haven R; St John, Lisa S; Federico, Lorenzo; Meraz, Ismail M; Roth, Jack A; Sepesi, Boris; Majidi, Mourad; Ruisaard, Kathryn; Clise-Dwyer, Karen; Roszik, Jason; Gibbons, Don L; Heymach, John V; Swisher, Stephen G; Bernatchez, Chantale; Alatrash, Gheath; Hanash, Samir; Molldrem, Jeffrey J

    2017-03-02

    Immunotherapies targeting immune checkpoints have proven efficacious in reducing the burden of lung cancer in patients; however, the antigenic targets of these reinvigorated T cells remain poorly defined. Lung cancer tumors contain tumor-associated macrophages (TAM) and neutrophils, which release the serine proteases neutrophil elastase (NE) and proteinase 3 (P3) into the tumor microenvironment. NE and P3 shape the antitumor adaptive immune response in breast cancer and melanoma. In this report, we demonstrate that lung cancer cells cross-presented the tumor-associated antigen PR1, derived from NE and P3. Additionally, NE and P3 enhanced the expression of human leukocyte antigen (HLA) class I molecules on lung cancer cells and induced unique, endogenous peptides in the immunopeptidome, as detected with mass spectrometry sequencing. Lung cancer patient tissues with high intratumoral TAMs were enriched for MHC class I genes and T-cell markers, and patients with high TAM and cytotoxic T lymphocyte (CTL) infiltration had improved overall survival. We confirmed the immunogenicity of unique, endogenous peptides with cytotoxicity assays against lung cancer cell lines, using CTLs from healthy donors that had been expanded against select peptides. Finally, CTLs specific for serine proteases-induced endogenous peptides were detected in lung cancer patients using peptide/HLA-A2 tetramers and were elevated in tumor-infiltrating lymphocytes. Thus, serine proteases in the tumor microenvironment of lung cancers promote the presentation of HLA class I immunogenic peptides that are expressed by lung cancer cells, thereby increasing the antigen repertoire that can be targeted in lung cancer. Cancer Immunol Res; 5(4); 1-11. ©2017 AACR.

  8. Presentation Capability of Compound Displays for Pressure and Force

    NASA Astrophysics Data System (ADS)

    Ohka, Masahiro; Kato, Keitaro; Fujiwara, Takehiro; Mitsuya, Yasunaga; Miyaoka, Tetsu

    The authors developed advanced haptic displays capable of stimulating the muscles and tendons of the forearms and tactile receptors in fingers to investigate tactile and force effects on simultaneous presentation. Display A is comprised of a master hand with two sets of tactile display with a 4-by-6 array of stimulus pins driven by micro-actuators and an articulated manipulator. Display B is comprised of an articulated manipulator and an 8-by-8 array type tactile display developed in a previous paper. A series of experiments was performed using the above A and B displays to verify the presentation capability of this display type. In Experiment I, subjects grasped virtual pegs and judged their diameters. In Experiment II, subjects tried to insert the pegs into holes. In Experiment III, the crossed-angle of a comparison texture was adjusted to bring it as close as possible to the standard texture fixed during experiments. Since diameter discrimination and insertion precision of the virtual peg were increased by tactile information, tactile-force presentation was effective for peg-in-hole for relatively large clearance. On the other hand, recognition capability for virtual texture was not enhanced compared to a mouse-mounted tactile display previously developed. While the pressure display is effective for instant of touch and peg rotation representations, rotation tactile imaging is not always effective for texture recognitions.

  9. Antigen presentation by peritoneal macrophages from young adult and old mice

    SciTech Connect

    Perkins, E.H.; Massucci, J.M.; Glover, P.L.

    1982-01-01

    Macrophages perform vital inductive and regulatory functions in immune processes and host defense mechanisms. However, macrophage function during senescence has not been extensively studied. Although antibody response is dramatically reduced in old animals, antigen presentation has never been directly assessed. Therefore, the antigen-presenting capabilities of purified peritoneal macrophages from young adult and old mice were studied by quantitatively measuring their ability to induce antigen specific proliferation of lymph node T lymphocytes. Increasing numbers (10/sup 2/ to 10/sup 5/) of macrophages from nonimmunized young adult (3 to 6 months) or aged (27 to 36 months) animals were cultured in the presence of antigen with a constant number (2 x 10/sup 5/) of column-separated popliteal lymph node cells from young adult mice. The latter had been immunized with the dinitrophenyl conjugate of bovine ..gamma..-globulin in complete Freund's adjuvant by footpad injection. Macrophages from old animals were equal to macrophages from young adult in stimulating T-lymphocyte proliferation, and the kinetics of incorporation was identical with increasing numbers of macrophages from either young adult or old animals. However, greater numbers of resident or induced peritoneal macrophages were always harvested from old animals. Differences in macrophage activity as assessed by different functional parameters may be reconciled by implicating subpopulations of macrophages that perform separate functions, e.g. Ia-positive antigen presenter and Ia-negative scavenger macrophages.

  10. Mesoscale resolution capability of altimetry: Present and future

    NASA Astrophysics Data System (ADS)

    Dufau, Claire; Orsztynowicz, Marion; Dibarboure, Gérald; Morrow, Rosemary; Le Traon, Pierre-Yves

    2016-07-01

    Wavenumber spectra of along-track Sea Surface Height from the most recent satellite radar altimetry missions [Jason-2, Cryosat-2, and SARAL/Altika) are used to determine the size of ocean dynamical features observable with the present altimetry constellation. A global analysis of the along-track 1-D mesoscale resolution capability of the present-day altimeter missions is proposed, based on a joint analysis of the spectral slopes in the mesoscale band and the error levels observed for horizontal wavelengths lower than 20km. The global sea level spectral slope distribution provided by Xu and Fu with Jason-1 data is revisited with more recent altimeter missions, and maps of altimeter error levels are provided and discussed for each mission. Seasonal variations of both spectral slopes and altimeter error levels are also analyzed for Jason-2. SARAL/Altika, with its lower error levels, is shown to detect smaller structures everywhere. All missions show substantial geographical and temporal variations in their mesoscale resolution capabilities, with variations depending mostly on the error level change but also on slight regional changes in the spectral slopes. In western boundary currents where the signal to noise ratio is favorable, the along-track mesoscale resolution is approximately 40 km for SARAL/AltiKa, 45 km for Cryosat-2, and 50 km for Jason-2. Finally, a prediction of the future 2-D mesoscale sea level resolution capability of the Surface Water and Ocean Topography (SWOT) mission is given using a simulated error level.

  11. Presentation of antigen to T lymphocytes by non-immune B-cell hybridoma clones: evidence for specific and non-specific presentation

    NASA Technical Reports Server (NTRS)

    Cohly, H. H.; Morrison, D. R.; Zouhair Atassi, M. Z.

    1989-01-01

    Non-immune SJL (H-2s) spleen cells were fused with non-secreting, non-antigen presenting (H-2d) Balb/c 653-myeloma cells and the hybridomas were cloned by two limiting dilutions. The resulting hybrid B-cell clones were tested for their antigen presentation capability to SJL T-cell lines that were specific for either lysozyme or myoglobin. In proliferative assays, 53% of the antigen presenting B-cell clones presented both myoglobin and lysozyme (general presenters) while the other 47% presented specifically either myoglobin or lysozyme (specific presenters). The ability to selectively present either myoglobin or lysozyme indicates that antigen presentation at the clonal level can be specific or non-specific depending on the particular B-cell clone.

  12. Presentation of antigen to T lymphocytes by non-immune B-cell hybridoma clones: evidence for specific and non-specific presentation

    NASA Technical Reports Server (NTRS)

    Cohly, H. H.; Morrison, D. R.; Zouhair Atassi, M. Z.

    1989-01-01

    Non-immune SJL (H-2s) spleen cells were fused with non-secreting, non-antigen presenting (H-2d) Balb/c 653-myeloma cells and the hybridomas were cloned by two limiting dilutions. The resulting hybrid B-cell clones were tested for their antigen presentation capability to SJL T-cell lines that were specific for either lysozyme or myoglobin. In proliferative assays, 53% of the antigen presenting B-cell clones presented both myoglobin and lysozyme (general presenters) while the other 47% presented specifically either myoglobin or lysozyme (specific presenters). The ability to selectively present either myoglobin or lysozyme indicates that antigen presentation at the clonal level can be specific or non-specific depending on the particular B-cell clone.

  13. Inhibitory effects of thymus-independent type 2 antigens on MHC class II-restricted antigen presentation: comparative analysis of carbohydrate structures and the antigen presenting cell.

    PubMed

    González-Fernández, M; Carrasco-Marín, E; Alvarez-Domínguez, C; Outschoorn, I M; Leyva-Cobián, F

    1997-02-25

    The role of thymus-independent type 2 (TI-2) antigens (polysaccharides) on the MHC-II-restricted processing of protein antigens was studied in vitro. In general, antigen presentation is inhibited when both peritoneal and splenic macrophages (M phi) as well as Küpffer cells (KC) are preincubated with acidic polysaccharides or branched dextrans. However, the inhibitory effect of neutral polysaccharides was minimal when KC were used as antigen presenting cells (APC). Morphological evaluation of the uptake of fluoresceinated polysaccharides clearly correlates with this selective and differential interference. Polysaccharides do not block MHC-I-restricted antigen presentation. Some chemical characteristics shared by different saccharides seem to be specially related to their potential inhibitory abilities: (i) those where two anomeric carbon atoms of two interlinked sugars and (ii) those containing several sulfate groups per disaccharide repeating unit. No polysaccharide being inhibitory in M phi abrogated antigen processing in other APC: lipopolysaccharide-activated B cells, B lymphoma cells, or dendritic cells (DC). Using radiolabeled polysaccharides it was observed that DC and B cells incorporated less radioactivity as a function of time than M phi. Morphological evaluation of these different APC incubated for extended periods of time with inhibitory concentrations of polysaccharides revealed intense cytoplasmic vacuolization in M phi but not in B cells or DC. The large majority of M phi lysosomes containing polysaccharides fail to fuse with incoming endocytic vesicles and delivery of fluid-phase tracers was reduced, suggesting that indigestible carbohydrates reduced the fusion of these loaded lysosomes with endosomes containing recently internalized tracers. It is suggested that the main causes of this antigen presentation blockade are (i) the chemical characteristics of certain carbohydrates and whether the specific enzymatic machinery for their intracellular

  14. Past and Present Large Solid Rocket Motor Test Capabilities

    NASA Technical Reports Server (NTRS)

    Kowalski, Robert R.; Owen, David B., II

    2011-01-01

    A study was performed to identify the current and historical trends in the capability of solid rocket motor testing in the United States. The study focused on test positions capable of testing solid rocket motors of at least 10,000 lbf thrust. Top-level information was collected for two distinct data points plus/minus a few years: 2000 (Y2K) and 2010 (Present). Data was combined from many sources, but primarily focused on data from the Chemical Propulsion Information Analysis Center s Rocket Propulsion Test Facilities Database, and heritage Chemical Propulsion Information Agency/M8 Solid Rocket Motor Static Test Facilities Manual. Data for the Rocket Propulsion Test Facilities Database and heritage M8 Solid Rocket Motor Static Test Facilities Manual is provided to the Chemical Propulsion Information Analysis Center directly from the test facilities. Information for each test cell for each time period was compiled and plotted to produce a graphical display of the changes for the nation, NASA, Department of Defense, and commercial organizations during the past ten years. Major groups of plots include test facility by geographic location, test cells by status/utilization, and test cells by maximum thrust capability. The results are discussed.

  15. The Role of Antigen Presenting Cells in Multiple Sclerosis

    PubMed Central

    Chastain, Emily M. L.; Duncan, D'Anne S.; Rodgers, Jane M.; Miller, Stephen D.

    2010-01-01

    Multiple Sclerosis (MS) is a debilitating T cell-mediated autoimmune disease of the central nervous system (CNS). Animal models of MS, such as experimental autoimmune encephalomyelitis (EAE) and Theiler's murine encephalomyelitis virus-Induced demyelinating disease (TMEV-IDD) have given light to cellular mechanisms involved in the initiation and progression of this organ-specific autoimmune disease. Within the CNS, antigen presenting cells (APC) such as microglia and astrocytes participate as first line defenders against infections or inflammation. However, during chronic inflammation they can participate in perpetuating the self-destructive environment by secretion of inflammatory factors and/or presentation of myelin epitopes to autoreactive T cells. Dendritic cells (DC) are also participants in the presentation of antigen to T cells, even within the CNS. While the APCs alone are not solely responsible for mediating the destruction to the myelin sheath, they are critical players in perpetuating the inflammatory milieu. This review will highlight relevant studies which have provided insight to the roles played by microglia, DCs and astrocytes in the context of CNS autoimmunity. PMID:20637861

  16. Satellite radar altimeters - Present and future oceanographic capabilities

    NASA Technical Reports Server (NTRS)

    Townsend, W. F.; Mcgoogan, J. T.; Walsh, E. J.

    1981-01-01

    Satellite radar altimeters have the ability to provide information related to ocean wave heights, wind speed, and currents. The present investigation has the objective to demonstrate the current capabilities and to indicate ways to increase the information content of the altimeter return through the use of wider bandwidth, higher pulse repetition frequencies (PRF), and multibeam. Altimeters aboard Skylab, Geos-3, and Seasat-1 have provided investigators with valuable experience in translating the radar observables into oceanic parameters. Basically, an altimeter transmits a narrow pulse and measures the time interval until the return energy from the ocean surface is received. That direct measure of the satellite altitude can be interpreted in terms of surface topography. Attention is given to altimeter oceanographic measurements, altimeter return pulse characteristics, satellite pointing and surface slopes, the adaptive tracker for terrain mapping, and a multibeam altimeter.

  17. Phenotypic and functional profiling of mouse intestinal antigen presenting cells

    PubMed Central

    Harusato, Akihito; Flannigan, Kyle L.; Geem, Duke; Denning, Timothy L.

    2015-01-01

    The microbiota that populates the mammalian intestine consists of hundreds of trillions of bacteria that are separated from underlying immune cells by a single layer of epithelial cells. The intestinal immune system effectively tolerates components of the microbiota that provide benefit to the host while remaining poised to eliminate those that are harmful. Antigen presenting cells, especially macrophages and dendritic cells, play important roles in maintaining intestinal homeostasis via their ability to orchestrate appropriate responses to the microbiota. Paramount to elucidating intestinal macrophage- and dendritic cell-mediated functions is the ability to effectively isolate and identify these cells from a complex cellular environment. In this review, we summarize methodology for the isolation and phenotypic characterization of macrophages and DCs from the mouse intestine and discuss how this may be useful for gaining insight into the mechanisms by which mucosal immune tolerance is maintained. PMID:25891794

  18. Antigen presenting cells in situ: their identification and involvement in immunopathology.

    PubMed Central

    Poulter, L W

    1983-01-01

    Macrophages and other dendritic non-lymphoid cells have been shown to be functionally capable of presenting antigen to induce lymphocyte responses. These cells can now be studied in situ and distinguished, one from another, within normal tissues and sites of cellular infiltration. Analysis of the microenvironment within which these cells are found can be made with immunohistological methods using monoclonal antibodies (McAbs) and cytochemical techniques. In some cases McAbs are specific for particular types of antigen presenting cell. Using such reagents, evidence is accumulating that these cells may be intimately involved in the pathogenesis of immunoregulatory disorders. What is now required is a more definitive correlation between functional capacity and cell phenotype established with cells isolated from blood, and from normal and pathological tissues. If this is possible the immunopathologist may be able, not only to analyse complex microenvironments but also directly determine the interactions and mechanisms at play within the diseased tissues. PMID:6352095

  19. Modulation for antigen presentation in tuberculosis by using synthetic peptides.

    PubMed

    Méndez-Samperio, P; Jiménez-Zamudio, L

    1991-01-01

    Competition assay technology has been a very useful tool in the study of parasite antigens and has been inferred but never proven that this approach can be applied to select T-cell epitopes by using another microorganisms. In this study, HLA-restricted T-cell clones specific to synthetic peptides derived from the 65 kDa mycobacterial protein were used to investigate whether these peptides are able to compete with each other at the level of MHC-binding sites in tuberculosis. Fixed APCs were pulsed with suboptimal concentration of stimulator peptide in the presence of various concentrations of competitor peptide. The results showed that two peptides from this protein were able to compete with each other inducing a significant inhibition in the proliferation assays while there was no competition by using a control peptide. The amount of cross-reactivity was influenced by the peptide concentrations. More important was the observation that these peptides were able to bind to the same HLA-class II molecules therefore blocking the binding of each other. The fact that these peptides have not an identical amino acid sequence support the idea that the MHC-peptide interaction must have a broad specificity to be able to bind a large number of peptides. These results demonstrate that it is possible to modulate the antigen presentation by blocking the peptide MHC-class II interaction in tuberculosis and support the idea that this approach facilitates the selection of appropriate T-cell epitopes to be incorporated in a vaccine.

  20. Differential presentation of tumor antigen-derived epitopes by MHC-class I and antigen-positive tumor cells.

    PubMed

    Held, Gerhard; Neumann, Frank; Sturm, Christine; Kaestner, Lars; Dauth, Nina; de Bruijn, Diederik R; Renner, Christoph; Lipp, Peter; Pfreundschuh, Michael

    2008-10-15

    SSX2 is a member of the family of cancer/testis antigens. The SSX2 derived peptide SSX2(103-111) has been shown to be presented to cytotoxic T-lymphocytes (CTL) by Major-Histocompatibility (MHC) Class-I complexes after endogenous processing, more precisely by the allele HLA-A*0201. The HLA-A*0201- and SSX2-positive melanoma cell line SK-Mel-37 but not Me275 had been shown to elicit reactivity in SSX2(103-111) specific cytotoxic T-lymphocytes. To analyze the correlation between SSX2(103-111) presentation and T-cell stimulation, we intended to visualize presentation of SSX2(103-111) in these melanoma cell lines. Fab-antibodies were established from a human phage library with specificity for SSX2(103-111)/HLA-A*0201 complexes (but non-reactive with HLA-A*0201 or SSX2(103-111) alone) and used to visualize the presentation of SSX2(103-111) in the context of HLA-A*0201 by fluorescence microscopy. Presentation of SSX2(103-111) the context of HLA-A*0201 was demonstrated for the majority of SK-Mel-37, but for only a small fraction (<1%) of Me275 as indicated by a clear membrane-staining pattern in fluorescence microscopy. The presentation of SSX2(103-111) on SK-Mel37 and Me275, but not the expression of the SSX2 protein correlated with the capability of these cells to stimulate cells of an SSX2(103-111)-specific T-cell clone. MHC-peptide specific antibodies are a valuable tool for the analysis of antigenic peptides in the context of MHC-I molecules and for the structural definition of immunodominant epitopes.

  1. Carbohydrate-Mediated Targeting of Antigen to Dendritic Cells Leads to Enhanced Presentation of Antigen to T Cells

    PubMed Central

    Adams, Eddie W.; Ratner, Daniel M.; Seeberger, Peter H.; Hacohen, Nir

    2009-01-01

    The unique therapeutic value of dendritic cells (DCs) for the treatment of allergy, autoimmunity and transplant rejection is predicated upon our ability to selectively deliver antigens, drugs or nucleic acids to DCs in vivo. Here we describe a method for delivering whole protein antigens to DCs based on carbohydrate-mediated targeting of DC-expressed lectins. A series of synthetic carbohydrates was chemically-coupled to a model antigen, ovalbumin (OVA), and each conjugate was evaluated for its ability to increase the efficiency of antigen presentation by murine DCs to OVA-specific T cells (CD4+ and CD8+). In vitro data are presented that demonstrate that carbohydrate modification of OVA leads to a 50-fold enhancement of presentation of antigenic peptide to CD4+ T cells. A tenfold enhancement is observed for CD8+ T cells; this indicates that the targeted lectin(s) can mediate cross-presentation of antigens on MHC class I. Our data indicate that the observed enhancements in antigen presentation are unique to OVA that is conjugated to complex oligosaccharides, such as a high-mannose nonasaccharide, but not to monosaccharides. Taken together, our data suggest that a DC targeting strategy that is based upon carbohydrate-lectin interactions is a promising approach for enhancing antigen presentation via class I and class II molecules. PMID:18186095

  2. Presentation of antigen to T lymphocytes by non-immune B-cell hybridoma clones: evidence for specific and non-specific presentation

    NASA Technical Reports Server (NTRS)

    Cohly, H. H.; Morrison, D. R.; Atassi, M. Z.

    1988-01-01

    Non-immune SJL (H-2s) spleen cells were fused with (H-2d) Balb/c 653-myeloma cells and the hybridomas were cloned by two limiting dilutions. The resulting hybrid B- cell clones were tested for their antigen presentation capability to SJL T-cell lines that were specific for either lysozyme or myoglobin. In proliferative assays, 53% of the antigen presenting B-cell clones were able to present both myoglobin and lysozyme (general presenters) while the other 47% presented specifically either myoglobin or lysozyme (specific presenters). The ability to selectively present either myoglobin or lysozyme indicates that antigen presentation at the clonal level can be specific or non-specific depending on the particular B-cell clone.

  3. Presentation of antigen to T lymphocytes by non-immune B-cell hybridoma clones: evidence for specific and non-specific presentation

    NASA Technical Reports Server (NTRS)

    Cohly, H. H.; Morrison, D. R.; Atassi, M. Z.

    1988-01-01

    Non-immune SJL (H-2s) spleen cells were fused with (H-2d) Balb/c 653-myeloma cells and the hybridomas were cloned by two limiting dilutions. The resulting hybrid B- cell clones were tested for their antigen presentation capability to SJL T-cell lines that were specific for either lysozyme or myoglobin. In proliferative assays, 53% of the antigen presenting B-cell clones were able to present both myoglobin and lysozyme (general presenters) while the other 47% presented specifically either myoglobin or lysozyme (specific presenters). The ability to selectively present either myoglobin or lysozyme indicates that antigen presentation at the clonal level can be specific or non-specific depending on the particular B-cell clone.

  4. Localization of splenic cells with antigen-transporting capability in the chicken.

    PubMed

    del Cacho, E; Gallego, M; Arnal, C; Bascuas, J A

    1995-01-01

    The objective of the present study is to investigate the migration pattern of the splenic dendritic cell of the chicken named the ellipsoid-associated cell (EAC) from the site of initial location at the periphery of the ellipsoid to the splenic T- and B-dependent areas. Bovine serum albumin bound to biotin and conjugated to gold particles was used as a histochemically identifiable antigen detected as a peroxidase reaction. The antigen was intravenously injected, and subsequently its pattern of distribution in a time sequence and within the tissue was examined at the light and electron microscopy levels. In addition, an hour prior to sacrifice, the chickens received a single injection of the thymidine analogue 5-bromo-2'-deoxyuridine, in order to quantify the number of DNA synthesizing cells and to establish a relationship between the migrating EAC and the rate of mitosis in the white pulp. The observations showed that between 12 hours and 3 days after the second antigen administration the labeled EAC, which was first located around the ellipsoid, progressively reached further areas with time towards the periarteriolar lymphoid sheaths, where newly formed germinal centers appeared. Furthermore, the rate of cell proliferation within the white pulp was associated with the arrival of the antigen-transporting EAC. The results suggest that migrating EAC have a role as both antigen-transporting cell and antigen-presenting cell in the T- and B-dependent areas, as a result of which migrating EAC is transiently found in periellipsoidal white pulp, then periarteriolar lymphoid sheaths, and finally germinal centers, where it may function as an interdigitating cell or as a follicular dendritic cell, depending on its location. Thus, we conclude that the EACs are precursors of both interdigitating and follicular dendritic cells.

  5. A new TLR2 agonist promotes cross-presentation by mouse and human antigen presenting cells.

    PubMed

    Santone, Melissa; Aprea, Susanna; Wu, Tom Y H; Cooke, Michael P; Mbow, M Lamine; Valiante, Nicholas M; Rush, James S; Dougan, Stephanie; Avalos, Ana; Ploegh, Hidde; De Gregorio, Ennio; Buonsanti, Cecilia; D'Oro, Ugo

    2015-01-01

    Cross-presentation is the process by which professional APCs load peptides from an extracellularly derived protein onto class I MHC molecules to trigger a CD8(+) T cell response. The ability to enhance this process is therefore relevant for the development of antitumor and antiviral vaccines. We investigated a new TLR2-based adjuvant, Small Molecule Immune Potentiator (SMIP) 2.1, for its ability to stimulate cross-presentation. Using OVA as model antigen, we demonstrated that a SMIP2.1-adjuvanted vaccine formulation induced a greater CD8(+) T cell response, in terms of proliferation, cytokine production and cytolytic activity, than a non-adjuvanted vaccine. Moreover, using an OVA-expressing tumor model, we showed that the CTLs induced by the SMIP2.1 formulated vaccine inhibits tumor growth in vivo. Using a BCR transgenic mouse model we found that B cells could cross-present the OVA antigen when stimulated with SMIP2.1. We also used a flow cytometry assay to detect activation of human CD8(+) T cells isolated from human PBMCs of cytomegalovirus-seropositive donors. Stimulation with SMIP2.1 increased the capacity of human APCs, pulsed in vitro with the pp65 CMV protein, to activate CMV-specific CD8(+) T cells. Therefore, vaccination with an exogenous antigen formulated with SMIP2.1 is a successful strategy for the induction of a cytotoxic T cell response along with antibody production.

  6. Isolation of a peptide binding protein and its role in antigen presentation

    SciTech Connect

    Lakey, E.; Pierce, S.K.; Margoliash, E.

    1986-03-05

    A mouse T cell hybrid, TPc9.1, recognizes pigeon cytochrome c (Pc) as processed and presented by histocompatible antigen presenting cells (APC). When paraformaldehyde fixed APC are employed, only a peptide fragment of Pc, Pc 81-104, and not the native Pc, is capable of stimulating TPc9.1 cells. Pc 81-104 appears to associate tightly with the APC surface since paraformaldehyde fixed APC which have been incubated with Pc 81-104 remain stimulatory following extensive washing. When APC are surface labeled with /sup 125/I, solubilized and affinity purified on Pc 81-104-Sepharose 4B columns, two predominant polypeptides of approximately 72 and 74 kd are isolated. Little or no immunoglobulin, Class I or Class II proteins are obtained under these conditions. Antisera from rabbits immunized with the affinity purified material, but not preimmune sera, block the activation of TPc 9.1 cells by Pc as well as Pc 81-104 when presented by live APC. Furthermore, these antisera are even more effective in blocking the activation of TPc9.1 cells by either APC which had been pulsed with Pc and then paraformaldehyde fixed, or by Pc 81-104 when added to paraformaldehyde fixed APC, suggesting that these antisera were not affecting antigen processing. Thus, these peptide binding proteins may play a role in antigen presentation, and they are being further characterized.

  7. Viral Sequestration of Antigen Subverts Cross Presentation to CD8+ T Cells

    PubMed Central

    Tewalt, Eric F.; Grant, Jean M.; Granger, Erica L.; Palmer, Douglas C.; Heuss, Neal D.; Gregerson, Dale S.; Restifo, Nicholas P.; Norbury, Christopher C.

    2009-01-01

    Virus-specific CD8+ T cells (TCD8+) are initially triggered by peptide-MHC Class I complexes on the surface of professional antigen presenting cells (pAPC). Peptide-MHC complexes are produced by two spatially distinct pathways during virus infection. Endogenous antigens synthesized within virus-infected pAPC are presented via the direct-presentation pathway. Many viruses have developed strategies to subvert direct presentation. When direct presentation is blocked, the cross-presentation pathway, in which antigen is transferred from virus-infected cells to uninfected pAPC, is thought to compensate and allow the generation of effector TCD8+. Direct presentation of vaccinia virus (VACV) antigens driven by late promoters does not occur, as an abortive infection of pAPC prevents production of these late antigens. This lack of direct presentation results in a greatly diminished or ablated TCD8+ response to late antigens. We demonstrate that late poxvirus antigens do not enter the cross-presentation pathway, even when identical antigens driven by early promoters access this pathway efficiently. The mechanism mediating this novel means of viral modulation of antigen presentation involves the sequestration of late antigens within virus factories. Early antigens and cellular antigens are cross-presented from virus-infected cells, as are late antigens that are targeted to compartments outside of the virus factories. This virus-mediated blockade specifically targets the cross-presentation pathway, since late antigen that is not cross-presented efficiently enters the MHC Class II presentation pathway. These data are the first to describe an evasion mechanism employed by pathogens to prevent entry into the cross-presentation pathway. In the absence of direct presentation, this evasion mechanism leads to a complete ablation of the TCD8+ response and a potential replicative advantage for the virus. Such mechanisms of viral modulation of antigen presentation must also be taken into

  8. Limited sufficiency of antigen presentation by dendritic cells in models of central nervous system autoimmunity.

    PubMed

    Wu, Gregory F; Shindler, Kenneth S; Allenspach, Eric J; Stephen, Tom L; Thomas, Hannah L; Mikesell, Robert J; Cross, Anne H; Laufer, Terri M

    2011-02-01

    Experimental autoimmune encephalomyelitis (EAE), a model for the human disease multiple sclerosis (MS), is dependent upon the activation and effector functions of autoreactive CD4 T cells. Multiple interactions between CD4 T cells and major histocompatibility class II (MHCII)+ antigen presenting cells (APCs) must occur in both the periphery and central nervous system (CNS) to elicit autoimmunity. The identity of the MHCII+ APCs involved throughout this process remains in question. We investigated which APC in the periphery and CNS mediates disease using transgenic mice with MHCII expression restricted to dendritic cells (DCs). MHCII expression restricted to DCs results in normal susceptibility to peptide-mediated EAE. Indeed, radiation-sensitive bone marrow-derived DCs were sufficient for all APC functions during peptide-induced disease. However, DCs alone were inefficient at promoting disease after immunization with the myelin protein myelin oligodendrocyte glycoprotein (MOG), even in the presence of MHCII-deficient B cells. Consistent with a defect in disease induction following protein immunization, antigen presentation by DCs alone was incapable of mediating spontaneous optic neuritis. These results indicate that DCs are capable of perpetuating CNS-targeted autoimmunity when antigens are readily available, but other APCs are required to efficiently initiate pathogenic cognate CD4 T cell responses.

  9. TAP2-defective RMA-S cells present Sendai virus antigen to cytotoxic T lymphocytes.

    PubMed

    Zhou, X; Glas, R; Momburg, F; Hämmerling, G J; Jondal, M; Ljunggren, H G

    1993-08-01

    The murine antigen-processing-defective mutant cell line RMA-S is leaky in the presentation of certain endogenously synthesized minor histocompatibility and viral antigens to major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocytes (CTL). The viral antigens include influenza virus nucleoprotein, vesicular stomatitis virus (VSV) nucleocapsid and Rauscher murine leukemia virus (MuLV) antigen. Here we demonstrate Sendai virus antigen presentation by the HAM2 (murine TAP2, transporter associated with antigen presentation type 2)-defective RMA-S cell line and compare antigen presentation after restoration of the defect by murine TAP1/2 gene transfection. Kinetic studies revealed that RMA-S cells required 2-3 h longer incubation and approximately 10 times higher doses of Sendai virus to reach the same level of killing as the RMA parental line. After transfection of RMA-S cells with the murine TAP1/2 gene, Sendai virus antigen presentation was restored to levels of the RMA wild-type line with regard to time of virus infection and dose of virus needed for sensitizing target cells. The presentation of Sendai virus antigen in RMA-S cells was sensitive to brefeldin A (BFA), suggesting that the presentation was mediated via the endogenous pathway. Our findings confirmed leakiness of antigen presentation in RMA-S cells and extended it to Sendai virus. The results underscored the role for intact expression of the TAP 1/2 molecules for efficient MHC class I-mediated antigen presentation.

  10. Wheeling and Dealing With Antigen Presentation in Tuberculosis.

    PubMed

    Hudrisier, Denis; Neyrolles, Olivier

    2016-03-01

    In tuberculosis, antigens are transferred from infected to uninfected dendritic cells. Does this favor T lymphocyte response and anti-mycobacterial host defense? In a recent report published in Cell Host & Microbe, Ernst and colleagues show that Mycobacterium tuberculosis seems to have hijacked this mechanism for its own benefit.

  11. Dendritic cell preactivation impairs MHC class II presentation of vaccines and endogenous viral antigens

    PubMed Central

    Young, Louise J.; Wilson, Nicholas S.; Schnorrer, Petra; Mount, Adele; Lundie, Rachel J.; La Gruta, Nicole L.; Crabb, Brendan S.; Belz, Gabrielle T.; Heath, William R.; Villadangos, Jose A.

    2007-01-01

    When dendritic cells (DCs) encounter signals associated with infection or inflammation, they become activated and undergo maturation. Mature DCs are very efficient at presenting antigens captured in association with their activating signal but fail to present subsequently encountered antigens, at least in vitro. Such impairment of MHC class II (MHC II) antigen presentation has generally been thought to be a consequence of down-regulation of endocytosis, so it might be expected that antigens synthesized by the DCs themselves (for instance, viral antigens) would still be presented by mature DCs. Here, we show that DCs matured in vivo could still capture and process soluble antigens, but were unable to present peptides derived from these antigens. Furthermore, presentation of viral antigens synthesized by the DCs themselves was also severely impaired. Indeed, i.v. injection of pathogen mimics, which caused systemic DC activation in vivo, impaired the induction of CD4 T cell responses against subsequently encountered protein antigens. This immunosuppressed state could be reversed by adoptive transfer of DCs loaded exogenously with antigens, demonstrating that impairment of CD4 T cell responses was due to lack of antigen presentation rather than to overt suppression of T cell activation. The biochemical mechanism underlying this phenomenon was the down-regulation of MHC II–peptide complex formation that accompanied DC maturation. These observations have important implications for the design of prophylactic and therapeutic DC vaccines and contribute to the understanding of the mechanisms causing immunosuppression during systemic blood infections. PMID:17978177

  12. Antigen Presenting Properties of a Myeloid Dendritic-Like Cell in Murine Spleen

    PubMed Central

    Hey, Ying-ying; O’Neill, Helen C.

    2016-01-01

    This paper distinguishes a rare subset of myeloid dendritic-like cells found in mouse spleen from conventional (c) dendritic cells (DC) in terms of phenotype, function and gene expression. These cells are tentatively named “L-DC” since they resemble dendritic-like cells produced in longterm cultures of spleen. L-DC can be distinguished on the basis of their unique phenotype as CD11bhiCD11cloMHCII-CD43+Ly6C-Ly6G-Siglec-F- cells. They demonstrate similar ability as cDC to uptake and retain complex antigens like mannan via mannose receptors, but much lower ability to endocytose and retain soluble antigen. While L-DC differ from cDC by their inability to activate CD4+ T cells, they are capable of antigen cross-presentation for activation of CD8+ T cells, although less effectively so than the cDC subsets. In terms of gene expression, CD8- cDC and CD8+ cDC are quite distinct from L-DC. CD8+ cDC are distinguishable from the other two subsets by expression of CD24a, Clec9a, Xcr1 and Tlr11, while CD8- cDC are distinguished by expression of Ccnd1 and H-2Eb2. L-DC are distinct from the two cDC subsets through upregulated expression of Clec4a3, Emr4, Itgam, Csf1r and CD300ld. The L-DC gene profile is quite distinct from that of cDC, confirming a myeloid cell type with distinct antigen presenting properties. PMID:27654936

  13. Antigen Presenting Properties of a Myeloid Dendritic-Like Cell in Murine Spleen.

    PubMed

    Hey, Ying-Ying; O'Neill, Helen C

    This paper distinguishes a rare subset of myeloid dendritic-like cells found in mouse spleen from conventional (c) dendritic cells (DC) in terms of phenotype, function and gene expression. These cells are tentatively named "L-DC" since they resemble dendritic-like cells produced in longterm cultures of spleen. L-DC can be distinguished on the basis of their unique phenotype as CD11bhiCD11cloMHCII-CD43+Ly6C-Ly6G-Siglec-F- cells. They demonstrate similar ability as cDC to uptake and retain complex antigens like mannan via mannose receptors, but much lower ability to endocytose and retain soluble antigen. While L-DC differ from cDC by their inability to activate CD4+ T cells, they are capable of antigen cross-presentation for activation of CD8+ T cells, although less effectively so than the cDC subsets. In terms of gene expression, CD8- cDC and CD8+ cDC are quite distinct from L-DC. CD8+ cDC are distinguishable from the other two subsets by expression of CD24a, Clec9a, Xcr1 and Tlr11, while CD8- cDC are distinguished by expression of Ccnd1 and H-2Eb2. L-DC are distinct from the two cDC subsets through upregulated expression of Clec4a3, Emr4, Itgam, Csf1r and CD300ld. The L-DC gene profile is quite distinct from that of cDC, confirming a myeloid cell type with distinct antigen presenting properties.

  14. Modulation of antigen presentation by autoreactive B cell clones specific for GAD65 from a type I diabetic patient

    PubMed Central

    BANGA, J P; MOORE, J K; DUHINDAN, N; MADEC, A M; VAN ENDERT, P M; ORGIAZZI, J; ENDL, J

    2004-01-01

    We used a GAD65-specific human B–T cell line cognate system in vitro to investigate the modulation of GAD65 presentation by autoantibody, assessed in a proliferation assay. Generally, if the T cell determinant overlaps or resides within the antibody epitope, effects of presentation are blunted while if they are distant can lead to potent presentation. For three different autoreactive B–T cell line cognate pairs, the modulation of GAD65 presentation followed the mode of overlapping or distant epitopes with resultant potent or undetectable presentation. However, other cognate pairs elicited variability in this pattern of presentation. Notably, one B cell line, DPC, whose antibody epitope did not overlap with the T cell determinants, was consistently poor in presenting GAD65. Using the fluorescent dye Alexa Fluor 647 conjugated to GAD65 to study receptor-mediated antigen endocytosis showed that all the antigen-specific B cell clones were efficient in intracellular accumulation of the antigen. Additionally, multicolour immunofluorescence microscopy showed that the internalized GAD65/surface IgG complexes were rapidly targeted to a perinuclear compartment in all GAD-specific B cell clones. This analysis also demonstrated that HLA-DM expression was reduced strongly in DPC compared to the stimulatory B cell clones. Thus the capability of antigen-specific B cells to capture and present antigen to human T cell lines is dependent on the spatial relationship of B and T cell epitopes as well other factors which contribute to the efficiency of presentation. PMID:14678267

  15. Polymer blend particles with defined compositions for targeting antigen to both class I and II antigen presentation pathways.

    PubMed

    Tran, Kenny K; Zhan, Xi; Shen, Hong

    2014-05-01

    Defense against many persistent and difficult-to-treat diseases requires a combination of humoral, CD4(+) , and CD8(+) T-cell responses, which necessitates targeting antigens to both class I and II antigen presentation pathways. In this study, polymer blend particles are developed by mixing two functionally unique polymers, poly(lactide-co-glycolide) (PLGA) and a pH-responsive polymer, poly(dimethylaminoethyl methacrylate-co-propylacrylic acid-co-butyl methacrylate) (DMAEMA-co-PAA-co-BMA). Polymer blend particles are shown to enable the delivery of antigens into both class I and II antigen presentation pathways in vitro. Increasing the ratio of the pH-responsive polymer in blend particles increases the degree of class I antigen presentation, while maintaining high levels of class II antigen presentation. In a mouse model, it is demonstrated that a significantly higher and sustained level of CD4(+) and CD8(+) T-cell responses, and comparable antibody responses, are elicited with polymer blend particles than PLGA particles and a conventional vaccine, Alum. The polymer blend particles offer a potential vaccine delivery platform to generate a combination of humoral and cell-mediated immune responses that insure robust and long-lasting immunity against many infectious diseases and cancers.

  16. Polymer blend particles with defined compositions for targeting antigen to both class I and II antigen presentation pathways

    PubMed Central

    Tran, Kenny K.; Zhan, Xi; Shen, Hong

    2013-01-01

    Defense against many persistent and difficult-to-treat diseases requires a combination of humoral, CD4+ and CD8+ T cell responses, which necessitates targeting antigens to both class I and II antigen presentation pathways. In this study, we developed polymer blend particles by mixing two functionally unique polymers, poly(lactide-co-glycolide) (PLGA) and a pH-responsive polymer, poly(dimethylaminoethyl methacrylate-co-propylacrylic acid-co-butyl methacrylate) (DMAEMA-co-PAA-co-BMA). We showed polymer blend particles enabled the delivery of antigens into both class I and II antigen presentation pathways in vitro. Increasing the ratio of the pH-responsive polymer in blend particles increased the degree of class I antigen presentation, while maintaining high levels of class II antigen presentation. In a mouse model, we demonstrated that a significantly higher and sustained level of CD4+ and CD8+ T cell responses, and comparable antibody responses, were elicited with polymer blend particles than PLGA particles and a conventional vaccine, Alum. The polymer blend particles offer a potential vaccine delivery platform to generate a combination of humoral and cell-mediated immune responses that insure robust and long-lasting immunity against many infectious diseases and cancers. PMID:24124123

  17. Impact of antigen-presenting cells on cytokine profiles of human Th clones established after stimulation with Mycobacterium tuberculosis antigens.

    PubMed Central

    Conradt, P; Kaufmann, S H

    1995-01-01

    Human T cells reactive with mycobacterial antigens are generally considered to correlate with a Th1 cytokine profile. Our data show that, in addition, Th0 and Th2 clones develop in bulk culture with appropriate antigen-presenting cells before cloning. CD4+ blasts activated by mycobacterial antigens were cloned, and their mRNA patterns for the interleukins (IL) IL-2, IL-4, IL-5, IL-6, and IL-10 and gamma interferon were characterized by reverse-transcribed PCR. Nonadherent, nonrosetting, enriched peripheral blood mononuclear cells promoted development of Th0; after further depletion of monocytes and natural killer cells, Th2 clones were also found. Epstein-Barr virus-transformed B cells, with specificity for the stimulating antigen, increased the proportion of Th2 clones. PMID:7729923

  18. A central role for HSC70 in regulating antigen trafficking and MHC class II presentation.

    PubMed

    Deffit, Sarah N; Blum, Janice S

    2015-12-01

    Cells rely on multiple intracellular trafficking pathways to capture antigens for proteolysis. The resulting peptides bind to MHC class II molecules to promote CD4(+) T cell recognition. Endocytosis enhances the capture of extracellular and cell surface bound antigens for processing and presentation, while autophagy pathways shunt cytoplasmic and nuclear antigens for presentation in the context of MHC class II molecules. Understanding how physiological changes and cellular stress alter antigen trafficking and the repertoire of peptides presented by class II molecules remains challenging, yet important in devising novel approaches to boost immune responses to pathogens and tumors. An abundant, constitutively expressed cytoplasmic chaperone, HSC70 plays a central role in modulating antigen transport within cells to control MHC class II presentation during nutrient stress. HSC70 may serve as a molecular switch to modulate endocytic and autophagy pathways, impacting the source of antigens delivered for MHC class II presentation during cellular stress.

  19. Dissecting the Tumor Myeloid Compartment Reveals Rare Activating Antigen Presenting Cells, Critical for T cell Immunity

    PubMed Central

    Broz, Miranda; Binnewies, Mikhail; Boldajipour, Bijan; Nelson, Amanda; Pollock, Joshua; Erle, David; Barczak, Andrea; Rosenblum, Michael; Daud, Adil; Barber, Diane; Amigorena, Sebastian; van’t Veer, Laura J.; Sperling, Anne; Wolf, Denise; Krummel, Matthew F.

    2014-01-01

    SUMMARY It is well understood that antigen-presenting cells (APC) within tumors typically do not maintain cytotoxic T cell (CTL) function, despite engaging them. Across multiple mouse tumor models and human tumor biopsies, we have delineated the intratumoral dendritic-cell (DC) populations as distinct from macrophage populations. Within these, CD103+ DCs are extremely sparse and yet remarkably capable CTL stimulators. These are uniquely dependent upon IRF8, Zbtb46 and Batf3 transcription factors and generated by GM-CSF and Flt3L cytokines. Regressing tumors have higher proportions of these cells, T-cell dependent immune clearance relies upon them, and abundance of their transcripts in human tumors correlates with clinical outcome. This cell type presents opportunities for prognostic and therapeutic approaches across multiple cancer types. PMID:25446897

  20. Direct laser writing of auxetic structures: present capabilities and challenges

    NASA Astrophysics Data System (ADS)

    Hengsbach, Stefan; Díaz Lantada, Andrés

    2014-08-01

    Auxetic materials (or metamaterials) are those with a negative Poisson ratio (NPR) and that display the unexpected property of lateral expansion when stretched, as well as an equal and opposing densification when compressed. Such geometries are being progressively employed in the development of novel products, especially in the fields of intelligent expandable actuators, shape morphing structures and minimally invasive implantable devices. Although several micromanufacturing technologies have already been applied to the development of auxetic geometries and devices, additional precision is needed to take full advantage of their special mechanical properties. In this study we present a very promising approach for the development of auxetic metamaterials and devices based on the use of direct laser writing. The process stands out for its precision and complex three-dimensional (3D) geometries attainable without the need of supporting structures. To our knowledge it represents one of the first examples of the application of this technology to the manufacture of auxetic geometries and mechanical metamaterials, with details even more remarkable than those shown in very recent studies, almost reaching the current limit of this additive manufacturing technology. We have used some special 3D auxetic designs whose remarkable NPR has been previously highlighted.

  1. Characterization of defectiveness in endogenous antigen presentation of novel murine cells established from methylcholanthrene-induced fibrosarcomas.

    PubMed Central

    Kuroda, K; Yamashina, K; Kitatani, N; Kagishima, A; Hamaoka, T; Hosaka, Y

    1995-01-01

    Three cell lines (4A1, 4C2 and 6D1 cells) derived from fibrosarcoma induced by the inoculation of 3-methylcholanthrene into C3H/HeN (H-2k) mice were examined for their ability to present antigens to CD8+ cytotoxic T lymphocytes (CTL). 6D1 and 4C2 cells were deficient in presenting endogenously synthesized influenza virus antigens to CTL, but they were able to present antigens when they were sensitized with a synthetic epitope peptide. The expression of the H-2 Kk gene in 4C2 and 6D1 cells was much reduced and was detectable only with Northern blot hybridization. The expression of two transporter genes (TAP1 and TAP2), examined by Northern hybridization, was also reduced in both cells, and negligible particularly in 4C2 cells. Interferon-gamma (IFN-gamma) treatment of these cells induced expression of Kk, TAP1 and TAP2 genes and rescued the defect of class I-restricted antigen presentation in 4C2 and 6D1 cells. Even after this treatment, however, antigen-presentation capability of 4C2 cells was still much lower than that of normal 4A1 cells. This finding suggests that 4C2 cells might have an additional defective gene(s), whose products are involved in the processing of class I-restricted antigen, besides the Kk and TAP genes, and this may explain the difficulty of 4C2 cells to induce tumour-specific immunity, as described previously. To our knowledge, the 4C2 cell is the first tumour cell postulated to have more than three defective genes involved in class I-restricted antigen presentation. Images Figure 3 Figure 4 Figure 5 Figure 6 PMID:7890298

  2. Quantitative immunophenotypic analysis of antigen-presenting cells involved in ectromelia virus antigen presentation in BALB/c and C57BL/6 mice.

    PubMed

    Szulc-Dąbrowska, Lidia; Gieryńska, Małgorzata; Boratyńska-Jasińska, Anna; Martyniszyn, Lech; Winnicka, Anna; Niemiałtowski, Marek G

    2013-08-01

    During mousepox in resistant (C57BL/6) or susceptible (BALB/c) strains of mice, stimulation of Th1 or Th2 cytokine immune response, respectively, is observed. Because mechanisms of different polarization of T cells remain elusive, in this study, we quantitatively assessed the phenotype of antigen-presenting cells (APCs) involved in ectromelia virus (ECTV) antigen presentation and cluster formation with effector cells in secondary lymphoid organs of BALB/c and C57BL/6 mice. We showed that both strains of mice display similar dynamics and kinetics of viral antigen presentation by CD11c(+) , CD11b(+) , and CD19(+) cells. CD11c(+) and CD11b(+) cells highly participated in viral antigen presentation during all stages of mousepox, whereas CD19(+) cells presented viral peptides later in infection. The main population of dendritic cells (DCs) engaged in ECTV antigen presentation and cell junction formation with effector cells was a population of myeloid CD11b(+) DCs (mDCs). We suggest that, on the one hand, ECTV may differentially affect the functions of APCs depending on the strain of mice. On the other hand, we suggest that some types of APCs, such as mDCs or other DCs subsets, have different abilities to direct the shape of immune response depending on the host resistance to mousepox.

  3. Impaired antigen presentation and potent phagocytic activity identifying tumor-tolerant human monocytes.

    PubMed

    Soares-Schanoski, Alessandra; Jurado, Teresa; Córdoba, Raúl; Siliceo, María; Fresno, Carlos Del; Gómez-Piña, Vanesa; Toledano, Victor; Vallejo-Cremades, Maria T; Alfonso-Iñiguez, Sergio; Carballo-Palos, Arkaitz; Fernández-Ruiz, Irene; Cubillas-Zapata, Carolina; Biswas, Subhra K; Arnalich, Francisco; García-Río, Francisco; López-Collazo, Eduardo

    2012-06-29

    Monocyte exposure to tumor cells induces a transient state in which these cells are refractory to further exposure to cancer. This phenomenon, termed "tumor tolerance", is characterized by a decreased production of proinflammatory cytokines in response to tumors. In the past, we found that this effect comprises IRAK-M up regulation and TLR4 and CD44 activation. Herein we have established a human model of tumor tolerance and have observed a marked down-regulation of MHCII molecules as well as the MHCII master regulator, CIITA, in monocytes/macrophages. These cells combine an impaired capability for antigen presentation with potent phagocytic activity and exhibit an M2-like phenotype. In addition circulating monocytes isolated from Chronic Lymphocytic Leukemia patients exhibited the same profile as tumor tolerant cells after tumor ex vivo exposition.

  4. Mobilizing monocytes to cross-present circulating viral antigen in chronic infection

    PubMed Central

    Gehring, Adam J.; Haniffa, Muzlifah; Kennedy, Patrick T.; Ho, Zi Zong; Boni, Carolina; Shin, Amanda; Banu, Nasirah; Chia, Adeline; Lim, Seng Gee; Ferrari, Carlo; Ginhoux, Florent; Bertoletti, Antonio

    2013-01-01

    Selection of antigens for therapeutic vaccination against chronic viral infections is complicated by pathogen genetic variations. We tested whether antigens present during persistent viral infections could provide a personalized antigenic reservoir for therapeutic T cell expansion in humans. We focused our study on the HBV surface antigen (HBsAg), which is present in microgram quantities in the serum of chronic HBV patients. We demonstrated by quantitative fluorescent microscopy that, out of 6 professional APC populations in the circulation, only CD14 monocytes (MNs) retained an HBsAg depot. Using TCR-redirected CD8+ T cells specific for MHC-I–restricted HBV epitopes, we showed that, despite being constantly exposed to antigen, ex vivo–isolated APCs did not constitutively activate HBV-specific CD8+ T cells. However, differentiation of HBsAg+ CD14 MNs from chronic patients to MN-derived DCs (moDCs) induced cross-presentation of the intracellular reservoir of viral antigen. We exploited this mechanism to cross-present circulating viral antigen and showed that moDCs from chronically infected patients stimulated expansion of autologous HBV-specific T cells. Thus, these data demonstrate that circulating viral antigen produced during chronic infection can serve as a personalized antigenic reservoir to activate virus-specific T cells. PMID:23908113

  5. The Other Function: Class II-Restricted Antigen Presentation by B Cells

    PubMed Central

    Adler, Lital N.; Jiang, Wei; Bhamidipati, Kartik; Millican, Matthew; Macaubas, Claudia; Hung, Shu-chen; Mellins, Elizabeth D.

    2017-01-01

    Mature B lymphocytes (B cells) recognize antigens using their B cell receptor (BCR) and are activated to become antibody-producing cells. In addition, and integral to the development of a high-affinity antibodies, B cells utilize the specialized major histocompatibility complex class II (MHCII) antigen presentation pathway to process BCR-bound and internalized protein antigens and present selected peptides in complex with MHCII to CD4+ T cells. This interaction influences the fate of both types of lymphocytes and shapes immune outcomes. Specific, effective, and optimally timed antigen presentation by B cells requires well-controlled intracellular machinery, often regulated by the combined effects of several molecular events. Here, we delineate and summarize these events in four steps along the antigen presentation pathway: (1) antigen capture and uptake by B cells; (2) intersection of internalized antigen/BCRs complexes with MHCII in peptide-loading compartments; (3) generation and regulation of MHCII/peptide complexes; and (4) exocytic transport for presentation of MHCII/peptide complexes at the surface of B cells. Finally, we discuss modulation of the MHCII presentation pathway across B cell development and maturation to effector cells, with an emphasis on the shaping of the MHCII/peptide repertoire by two key antigen presentation regulators in B cells: HLA-DM and HLA-DO. PMID:28386257

  6. Turning tumour cells into antigen presenting cells: The next step to improve cancer immunotherapy?

    PubMed

    de Charette, Marie; Marabelle, Aurélien; Houot, Roch

    2016-11-01

    Downregulation/loss of the antigen presentation is a major immune escape mechanism in cancer. It allows tumour cells to become 'invisible' and avoid immune attack by antitumour T cells. In tumour harbouring properties of professional antigen presenting cells (i.e. tumour B cells in lymphoma), downregulation/loss of the antigen presentation may also prevent direct priming of naïve T cells by tumour cells. Here, we review treatments that may induce/restore antigen presentation by the tumour cells. These treatments may increase the generation of antitumour T cells and/or their capacity to recognise and eliminate tumour cells. By forcing tumour cells to present their antigens, these treatments may sensitise patients to T cell-based immunotherapies, including checkpoint inhibitors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Enrichment and Expansion with Nanoscale Artificial Antigen Presenting Cells for Adoptive Immunotherapy.

    PubMed

    Perica, Karlo; Bieler, Joan Glick; Schütz, Christian; Varela, Juan Carlos; Douglass, Jacqueline; Skora, Andrew; Chiu, Yen Ling; Oelke, Mathias; Kinzler, Kenneth; Zhou, Shibin; Vogelstein, Bert; Schneck, Jonathan P

    2015-07-28

    Adoptive immunotherapy (AIT) can mediate durable regression of cancer, but widespread adoption of AIT is limited by the cost and complexity of generating tumor-specific T cells. Here we develop an Enrichment + Expansion strategy using paramagnetic, nanoscale artificial antigen presenting cells (aAPC) to rapidly expand tumor-specific T cells from rare naïve precursors and predicted neo-epitope responses. Nano-aAPC are capable of enriching rare tumor-specific T cells in a magnetic column and subsequently activating them to induce proliferation. Enrichment + Expansion resulted in greater than 1000-fold expansion of both mouse and human tumor-specific T cells in 1 week, with nano-aAPC based enrichment conferring a proliferation advantage during both in vitro culture and after adoptive transfer in vivo. Robust T cell responses were seen not only for shared tumor antigens, but also for computationally predicted neo-epitopes. Streamlining the rapid generation of large numbers of tumor-specific T cells in a cost-effective fashion through Enrichment + Expansion can be a powerful tool for immunotherapy.

  8. RNAi screen for kinases and phosphatases that play a role in antigen presentation by dendritic cells.

    PubMed

    Moita, Catarina F; Chora, Ângelo; Hacohen, Nir; Moita, Luis F

    2012-07-01

    Effective CD8(+) T-cell responses against tumor or microbial antigens that are not directly expressed in antigen-presenting cells (APCs) depend on the cross-presentation of these antigens on MHC class I in APCs. To identify signaling molecules that regulate cross-presentation, we used lentiviral-based RNA interference to test the roles of hundreds of kinases and phosphatases in this process. Our study uncovered eight previously unknown genes, consisting of one positive and seven negative regulators of antigen cross-presentation. Depletion of Acvr1c, a type I receptor for TGF-β family of signaling molecules, led to an increase in CD80 and CD86 co-stimulator surface expression and secreted IL-12 in mouse bone marrow-derived DCs, as well as antigen-specific T-cell proliferation.

  9. Targeted delivery of antigen processing inhibitors to antigen presenting cells via mannose receptors

    PubMed Central

    Raiber, Eun-Ang; Tulone, Calogero; Zhang”, Yanjing; Martinez-Pomares, Luisa; Steed, Emily; Sponaas, Anna M.; Langhorne, Jean; Noursadeghi, Mahdad

    2014-01-01

    Improved chemical inhibitors are required to dissect the role of specific antigen processing enzymes and to complement genetic models. In this study we explore the in vitro and in vivo properties of a novel class of targeted inhibitor of aspartic proteinases, in which pepstatin is coupled to mannosylated albumin (MPC6), creating an inhibitor with improved solubility and the potential for selective cell tropism. Using these compounds, we have demonstrated that MPC6 is taken up via mannose receptor facilitated endocytosis, leading to a slow but continuous accumulation of inhibitor within large endocytic vesicles within dendritic cells, and a parallel inhibition of intracellular aspartic proteinase activity. Inhibition of intracellular proteinase activity is associated with reduction in antigen processing activity, but this is epitope specific, preferentially inhibiting processing of T cell epitopes buried within compact proteinase-resistant protein domains. Unexpectedly, we have also demonstrated, using quenched fluorescent substrates, that little or no cleavage of the disulfide linker takes place within dendritic cells, but this does not appear to affect the activity of MPC6 as an inhibitor of cathepsins D and E in vitro and in vivo. Finally, we have shown that MPC6 selectively targets dendritic cells and macrophages in spleen in vivo. Access to non-lymphoid tissues is very limited in the steady state, but is strongly enhanced at local sites of inflammation. The strategy adopted for MPC6 synthesis may therefore represent a more general way to deliver chemical inhibitors to cells of the innate immune system, especially at sites of inflammation. PMID:20349916

  10. All-in-one dual-aptasensor capable of rapidly quantifying carcinoembryonic antigen.

    PubMed

    Khang, Harriet; Cho, Kelly; Chong, Stephanie; Lee, Ji Hoon

    2017-04-15

    Using a dual DNA aptamer (CEA aptamer linked to hemin aptamer), capable of rapidly capturing carcinoembryonic antigen (CEA) and hemin, an all-in-one dual-aptasensor with 1,1'-oxalyldiimidazole (ODI) chemiluminescence detection was developed for the early diagnosis of human cancer. CEA and hemin competitively bound with the dual DNA aptamer while the mixture in a detection cell was incubated for 30min at room temperature. When Amplex Red and H2O2 were added in the detection cell after the incubation, the yield of resorufin formed from the reaction Amplex Red and H2O2 depended on the concentration of HRP-mimicking G-quardruplex DNAzyme formed from the binding interaction between hemin and the dual DNA aptamer. Bright red light was observed with the addition of ODI and H2O2 in the detection cell containing resorufin. Relative CL intensity of all-in-one dual-aptasensor, operated with the competitive reaction of CEA and hemin in the presence of the dual aptamer, was exponentially decreased with the increase of CEA concentration in human serum. The limit of detection (LOD=3σ) of the all-in-one dual-aptasensor which operated with excellent accuracy, precision, and reproducibility was as low as 0.58ng/ml. The good correlation between the easy to use all-in-one dual-aptasensor and conventional enzyme-linked immunosorbent assay (ELISA), operated with time consuming procedures (e.g., long incubations and multiple washings), indicates that the rapid all-in-one dual-aptasensor can be applied as a novel clinical tool for the early diagnosis of breast cancer.

  11. Lipopeptides: a novel antigen repertoire presented by major histocompatibility complex class I molecules.

    PubMed

    Morita, Daisuke; Sugita, Masahiko

    2016-10-01

    Post-translationally modified peptides, such as those containing either phosphorylated or O-glycosylated serine/threonine residues, may be presented to cytotoxic T lymphocytes (CTLs) by MHC class I molecules. Most of these modified peptides are captured in the MHC class I groove in a similar manner to that for unmodified peptides. N-Myristoylated 5-mer lipopeptides have recently been identified as a novel chemical class of MHC class I-presented antigens. The rhesus classical MHC class I allele, Mamu-B*098, was found to be capable of binding N-myristoylated lipopeptides and presenting them to CTLs. A high-resolution X-ray crystallographic analysis of the Mamu-B*098:lipopeptide complex revealed that the myristic group as well as conserved C-terminal serine residue of the lipopeptide ligand functioned as anchors, whereas the short stretch of three amino acid residues located in the middle of the lipopeptides was only exposed externally with the potential to interact directly with specific T-cell receptors. Therefore, the modes of lipopeptide-ligand interactions with MHC class I and with T-cell receptors are novel and fundamentally distinct from that for MHC class I-presented peptides. Another lipopeptide-presenting MHC class I allele has now been identified, leading us to the prediction that MHC class I molecules may be separated on a functional basis into two groups: one presenting long peptides and the other presenting short lipopeptides. Since the N-myristoylation of viral proteins is often linked to pathogenesis, CTLs capable of sensing N-myristoylation may serve to control pathogenic viruses, raising the possibility for the development of a new type of lipopeptide vaccine. © 2016 John Wiley & Sons Ltd.

  12. Regulation of the actin cytoskeleton by Rho kinase controls antigen presentation by CD1d1

    PubMed Central

    Gallo, Richard M.; Khan, Masood A.; Shi, Jianjian; Kapur, Reuben; Wei, Lei; Bailey, Jennifer C.; Liu, Jianyun; Brutkiewicz, Randy R.

    2012-01-01

    CD1d molecules are major histocompatibility complex (MHC) class I-like molecules that present lipid antigens to Natural Killer T (NKT) cells. Although we have previously shown that several different cell signaling molecules can play a role in the control of antigen presentation by CD1d, a defined mechanism by which a cell signaling pathway regulates CD1d function has been unclear. In the current study, we have found that the Rho kinases, ROCK1 and ROCK2, negatively regulate both human and mouse CD1d-mediated antigen presentation. Inhibition of ROCK pharmacologically, through specific ROCK1 and ROCK2 shRNA, or by using dendritic cells generated from ROCK1-deficient mice all resulted in enhanced CD1d-mediated antigen presentation compared to controls. ROCK regulates the actin cytoskeleton by phosphorylating LIM kinase which, in turn, phosphorylates cofilin, prohibiting actin fiber depolymerization. Treatment of antigen presenting cells with the actin filament depolymerizing agent, cytochalasin D, as well as knockdown of LIM kinase by shRNA, resulted in enhanced antigen presentation to NKT cells by CD1d, consistent with our ROCK inhibition data. Therefore, our overall results reveal a model whereby CD1d-mediated antigen presentation is negatively regulated by ROCK via its effects on the actin cytoskeleton. PMID:22798677

  13. The Effect of Superparamagnetic Iron Oxide Nanoparticle Surface Charge on Antigen Cross-Presentation

    NASA Astrophysics Data System (ADS)

    Mou, Yongbin; Xing, Yun; Ren, Hongyan; Cui, Zhihua; Zhang, Yu; Yu, Guangjie; Urba, Walter J.; Hu, Qingang; Hu, Hongming

    2017-01-01

    Magnetic nanoparticles (NPs) of superparamagnetic iron oxide (SPIO) have been explored for different kinds of applications in biomedicine, mechanics, and information. Here, we explored the synthetic SPIO NPs as an adjuvant on antigen cross-presentation ability by enhancing the intracellular delivery of antigens into antigen presenting cells (APCs). Particles with different chemical modifications and surface charges were used to study the mechanism of action of antigen delivery. Specifically, two types of magnetic NPs, γFe2O3/APTS (3-aminopropyltrimethoxysilane) NPs and γFe2O3/DMSA (meso-2, 3-Dimercaptosuccinic acid) NPs, with the same crystal structure, magnetic properties, and size distribution were prepared. Then, the promotion of T-cell activation via dendritic cells (DCs) was compared among different charged antigen coated NPs. Moreover, the activation of the autophagy, cytosolic delivery of the antigens, and antigen degradation mediated by the proteasome and lysosome were measured. Our results indicated that positive charged γFe2O3/APTS NPs, but not negative charged γFe2O3/DMSA NPs, enhanced the cross-presentation ability of DCs. Increased cross-presentation ability induced by γFe2O3/APTS NPs was associated with increased cytosolic antigen delivery. On the contrary, γFe2O3/DMSA NPs was associated with rapid autophagy. Overall, our results suggest that antigen delivered in cytoplasm induced by positive charged particles is beneficial for antigen cross-presentation and T-cell activation. NPs modified with different chemistries exhibit diverse biological properties and differ greatly in their adjuvant potentials. Thus, it should be carefully considered many different effects of NPs to design effective and safe adjuvants.

  14. The Effect of Superparamagnetic Iron Oxide Nanoparticle Surface Charge on Antigen Cross-Presentation.

    PubMed

    Mou, Yongbin; Xing, Yun; Ren, Hongyan; Cui, Zhihua; Zhang, Yu; Yu, Guangjie; Urba, Walter J; Hu, Qingang; Hu, Hongming

    2017-12-01

    Magnetic nanoparticles (NPs) of superparamagnetic iron oxide (SPIO) have been explored for different kinds of applications in biomedicine, mechanics, and information. Here, we explored the synthetic SPIO NPs as an adjuvant on antigen cross-presentation ability by enhancing the intracellular delivery of antigens into antigen presenting cells (APCs). Particles with different chemical modifications and surface charges were used to study the mechanism of action of antigen delivery. Specifically, two types of magnetic NPs, γFe2O3/APTS (3-aminopropyltrimethoxysilane) NPs and γFe2O3/DMSA (meso-2, 3-Dimercaptosuccinic acid) NPs, with the same crystal structure, magnetic properties, and size distribution were prepared. Then, the promotion of T-cell activation via dendritic cells (DCs) was compared among different charged antigen coated NPs. Moreover, the activation of the autophagy, cytosolic delivery of the antigens, and antigen degradation mediated by the proteasome and lysosome were measured. Our results indicated that positive charged γFe2O3/APTS NPs, but not negative charged γFe2O3/DMSA NPs, enhanced the cross-presentation ability of DCs. Increased cross-presentation ability induced by γFe2O3/APTS NPs was associated with increased cytosolic antigen delivery. On the contrary, γFe2O3/DMSA NPs was associated with rapid autophagy. Overall, our results suggest that antigen delivered in cytoplasm induced by positive charged particles is beneficial for antigen cross-presentation and T-cell activation. NPs modified with different chemistries exhibit diverse biological properties and differ greatly in their adjuvant potentials. Thus, it should be carefully considered many different effects of NPs to design effective and safe adjuvants.

  15. Regulation of MHC II and CD1 antigen presentation: from ubiquity to security.

    PubMed

    Gelin, Catherine; Sloma, Ivan; Charron, Dominique; Mooney, Nuala

    2009-02-01

    MHC class II and CD1-mediated antigen presentation on various APCs [B cells, monocytes, and dendritic cells (DC)] are subject to at least three distinct levels of regulation. The first one concerns the expression and structure of the antigen-presenting molecules; the second is based on the extracellular environment and signals of danger detected. However, a third level of regulation, which has been largely overlooked, is determined by lateral associations between antigen-presenting molecules and other proteins, their localization in specialized microdomains within the plasma membrane, and their trafficking pathways. This review focuses on features common to MHC II and CD1 molecules in their ability to activate specific T lymphocytes with the objective of addressing one basic question: What are the mechanisms regulating antigen presentation by MHC II and CD1 molecules within the same cell? Recent studies in immature DC, where MHC II and CD1 are coexpressed, suggest that the invariant chain (Ii) regulates antigen presentation by either protein. Ii could therefore favor MHC II or CD1 antigen presentation and thereby discriminate between antigens.

  16. Enhanced Direct Major Histocompatibility Complex Class I Self-Antigen Presentation Induced by Chlamydia Infection.

    PubMed

    Cram, Erik D; Simmons, Ryan S; Palmer, Amy L; Hildebrand, William H; Rockey, Daniel D; Dolan, Brian P

    2015-11-23

    The direct major histocompatibility complex (MHC) class I antigen presentation pathway ensures intracellular peptides are displayed at the cellular surface for recognition of infected or transformed cells by CD8(+) cytotoxic T lymphocytes. Chlamydia spp. are obligate intracellular bacteria and, as such, should be targeted by CD8(+) T cells. It is likely that Chlamydia spp. have evolved mechanisms to avoid the CD8(+) killer T cell responses by interfering with MHC class I antigen presentation. Using a model system of self-peptide presentation which allows for posttranslational control of the model protein's stability, we tested the ability of various Chlamydia species to alter direct MHC class I antigen presentation. Infection of the JY lymphoblastoid cell line limited the accumulation of a model host protein and increased presentation of the model-protein-derived peptides. Enhanced self-peptide presentation was detected only when presentation was restricted to defective ribosomal products, or DRiPs, and total MHC class I levels remained unaltered. Skewed antigen presentation was dependent on a bacterial synthesized component, as evidenced by reversal of the observed phenotype upon preventing bacterial transcription, translation, and the inhibition of bacterial lipooligosaccharide synthesis. These data suggest that Chlamydia spp. have evolved to alter the host antigen presentation machinery to favor presentation of defective and rapidly degraded forms of self-antigen, possibly as a mechanism to diminish the presentation of peptides derived from bacterial proteins.

  17. Enhanced Direct Major Histocompatibility Complex Class I Self-Antigen Presentation Induced by Chlamydia Infection

    PubMed Central

    Cram, Erik D.; Simmons, Ryan S.; Palmer, Amy L.; Hildebrand, William H.; Rockey, Daniel D.

    2015-01-01

    The direct major histocompatibility complex (MHC) class I antigen presentation pathway ensures intracellular peptides are displayed at the cellular surface for recognition of infected or transformed cells by CD8+ cytotoxic T lymphocytes. Chlamydia spp. are obligate intracellular bacteria and, as such, should be targeted by CD8+ T cells. It is likely that Chlamydia spp. have evolved mechanisms to avoid the CD8+ killer T cell responses by interfering with MHC class I antigen presentation. Using a model system of self-peptide presentation which allows for posttranslational control of the model protein's stability, we tested the ability of various Chlamydia species to alter direct MHC class I antigen presentation. Infection of the JY lymphoblastoid cell line limited the accumulation of a model host protein and increased presentation of the model-protein-derived peptides. Enhanced self-peptide presentation was detected only when presentation was restricted to defective ribosomal products, or DRiPs, and total MHC class I levels remained unaltered. Skewed antigen presentation was dependent on a bacterial synthesized component, as evidenced by reversal of the observed phenotype upon preventing bacterial transcription, translation, and the inhibition of bacterial lipooligosaccharide synthesis. These data suggest that Chlamydia spp. have evolved to alter the host antigen presentation machinery to favor presentation of defective and rapidly degraded forms of self-antigen, possibly as a mechanism to diminish the presentation of peptides derived from bacterial proteins. PMID:26597986

  18. A fully synthetic glycopeptide antitumor vaccine based on multiple antigen presentation on a hyperbranched polymer.

    PubMed

    Glaffig, Markus; Palitzsch, Björn; Hartmann, Sebastian; Schüll, Christoph; Nuhn, Lutz; Gerlitzki, Bastian; Schmitt, Edgar; Frey, Holger; Kunz, Horst

    2014-04-07

    For antitumor vaccines both the selected tumor-associated antigen, as well as the mode of its presentation, affect the immune response. According to the principle of multiple antigen presentation, a tumor-associated MUC1 glycopeptide combined with the immunostimulating T-cell epitope P2 from tetanus toxoid was coupled to a multi-functionalized hyperbranched polyglycerol by "click chemistry". This globular polymeric carrier has a flexible dendrimer-like structure, which allows optimal antigen presentation to the immune system. The resulting fully synthetic vaccine induced strong immune responses in mice and IgG antibodies recognizing human breast-cancer cells.

  19. Synovial fluid antigen-presenting cells unmask peripheral blood T cell responses to bacterial antigens in inflammatory arthritis.

    PubMed Central

    Life, P F; Viner, N J; Bacon, P A; Gaston, J S

    1990-01-01

    We and others have previously shown that synovial fluid (SF) mononuclear cells (MC) from patients with both reactive arthritis and other inflammatory arthritides proliferate in vitro in response to bacteria clinically associated with the triggering of reactive arthritis. In all cases, such SFMC responses are greater than the corresponding peripheral blood (PB) MC responses, often markedly so, and the mechanism for this is unclear. We have investigated this phenomenon by comparing the relative abilities of irradiated non-T cells derived from PB and SF to support autologous T cell responses to ReA-associated bacteria. Seven patients whose SFMC had been shown previously to respond to bacteria were studied. We demonstrate antigen-specific responses of PB T cells to bacteria in the presence of SF non-T cells which are in marked contrast to the minimal responses of either unfractionated PBMC or PB T cells reconstituted with PB non-T cells. We also show that PB, but not SF T cells respond strongly to autologous SF non-T cells in the absence of antigen or mitogen. These findings demonstrate that SF antigen-presenting cells (APC) are potent activators of PB T cells. We conclude that the contrasting responses of SFMC and PBMC to bacterial antigens may be accounted for at least in part by an enhanced ability of SF APC to support T cell proliferative responses. PMID:2311298

  20. Identifying a Small Molecule Blocking Antigen Presentation in Autoimmune Thyroiditis*

    PubMed Central

    Li, Cheuk Wun; Menconi, Francesca; Osman, Roman; Mezei, Mihaly; Jacobson, Eric M.; Concepcion, Erlinda; David, Chella S.; Kastrinsky, David B.; Ohlmeyer, Michael; Tomer, Yaron

    2016-01-01

    We previously showed that an HLA-DR variant containing arginine at position 74 of the DRβ1 chain (DRβ1-Arg74) is the specific HLA class II variant conferring risk for autoimmune thyroid diseases (AITD). We also identified 5 thyroglobulin (Tg) peptides that bound to DRβ1-Arg74. We hypothesized that blocking the binding of these peptides to DRβ1-Arg74 could block the continuous T-cell activation in thyroiditis needed to maintain the autoimmune response to the thyroid. The aim of the current study was to identify small molecules that can block T-cell activation by Tg peptides presented within DRβ1-Arg74 pockets. We screened a large and diverse library of compounds and identified one compound, cepharanthine that was able to block peptide binding to DRβ1-Arg74. We then showed that Tg.2098 is the dominant peptide when inducing experimental autoimmune thyroiditis (EAT) in NOD mice expressing human DRβ1-Arg74. Furthermore, cepharanthine blocked T-cell activation by thyroglobulin peptides, in particular Tg.2098 in mice that were induced with EAT. For the first time we identified a small molecule that can block Tg peptide binding and presentation to T-cells in autoimmune thyroiditis. If confirmed cepharanthine could potentially have a role in treating human AITD. PMID:26703475

  1. Identifying a Small Molecule Blocking Antigen Presentation in Autoimmune Thyroiditis.

    PubMed

    Li, Cheuk Wun; Menconi, Francesca; Osman, Roman; Mezei, Mihaly; Jacobson, Eric M; Concepcion, Erlinda; David, Chella S; Kastrinsky, David B; Ohlmeyer, Michael; Tomer, Yaron

    2016-02-19

    We previously showed that an HLA-DR variant containing arginine at position 74 of the DRβ1 chain (DRβ1-Arg74) is the specific HLA class II variant conferring risk for autoimmune thyroid diseases (AITD). We also identified 5 thyroglobulin (Tg) peptides that bound to DRβ1-Arg74. We hypothesized that blocking the binding of these peptides to DRβ1-Arg74 could block the continuous T-cell activation in thyroiditis needed to maintain the autoimmune response to the thyroid. The aim of the current study was to identify small molecules that can block T-cell activation by Tg peptides presented within DRβ1-Arg74 pockets. We screened a large and diverse library of compounds and identified one compound, cepharanthine that was able to block peptide binding to DRβ1-Arg74. We then showed that Tg.2098 is the dominant peptide when inducing experimental autoimmune thyroiditis (EAT) in NOD mice expressing human DRβ1-Arg74. Furthermore, cepharanthine blocked T-cell activation by thyroglobulin peptides, in particular Tg.2098 in mice that were induced with EAT. For the first time we identified a small molecule that can block Tg peptide binding and presentation to T-cells in autoimmune thyroiditis. If confirmed cepharanthine could potentially have a role in treating human AITD.

  2. Killer Artificial Antigen Presenting Cells (KaAPC) for Efficient In Vitro Depletion of Human Antigen-specific T Cells

    PubMed Central

    Schütz, Christian; Fleck, Martin; Schneck, Jonathan P.; Oelke, Mathias

    2014-01-01

    Current treatment of T cell mediated autoimmune diseases relies mostly on strategies of global immunosuppression, which, in the long term, is accompanied by adverse side effects such as a reduced ability to control infections or malignancies. Therefore, new approaches need to be developed that target only the disease mediating cells and leave the remaining immune system intact. Over the past decade a variety of cell based immunotherapy strategies to modulate T cell mediated immune responses have been developed. Most of these approaches rely on tolerance-inducing antigen presenting cells (APC). However, in addition to being technically difficult and cumbersome, such cell-based approaches are highly sensitive to cytotoxic T cell responses, which limits their therapeutic capacity. Here we present a protocol for the generation of non-cellular killer artificial antigen presenting cells (KaAPC), which allows for the depletion of pathologic T cells while leaving the remaining immune system untouched and functional. KaAPC is an alternative solution to cellular immunotherapy which has potential for treating autoimmune diseases and allograft rejections by regulating undesirable T cell responses in an antigen specific fashion. PMID:25145915

  3. Identification of a peptide binding protein that plays a role in antigen presentation

    SciTech Connect

    Lakey, E.K.; Margoliash, E.; Pierce, S.K.

    1987-03-01

    The helper T-cell response to globular proteins appears, in general, to require intracellular processing of the antigen, such that a peptide fragment containing the T-cell antigenic determinant is released and transported to and held on the surface of an Ia-expressing, antigen-presenting cell. However, the molecular details underlying these phenomena are largely unknown. The means by which antigenic peptides are anchored on the antigen-presenting cell surface was investigated. A cell surface protein is identified that was isolated by it ability to bind to a 24-amino acid peptide fragment of pigeon cytochrome c, residues 81-104, containing the major antigenic determinant for B10.A mouse T cells. This peptide binding protein, purified from (/sup 35/S)methionine-labeled cells, appears as two discrete bands of approx. =72 and 74 kDa after NaDodSO/sub 4//PAGE. The protein can be eluted from the peptide affinity column with equivalent concentrations of either the antigenic pigeon cytochrome c peptide or the corresponding nonantigenic peptide of mouse cytochrome c. However, it does not bind to the native cytochromes c, either of pigeon or mouse, and thus the protein appears to recognize some structure available only in the free peptides. This protein plays a role in antigen presentation. Its expression is not major histocompatibility complex-restricted in that the blocking activity of the antisera can be absorbed on spleen cells from mice of different haplotypes. This peptide binding protein can be isolated from a variety of cell types, including B cells, T cells, and fibroblasts. The anchoring of processed peptides on the cell surface by such a protein may play a role in antigen presentation.

  4. NY-ESO-1 antigen-reactive T cell receptors exhibit diverse therapeutic capability

    PubMed Central

    Sommermeyer, Daniel; Conrad, Heinke; Krönig, Holger; Gelfort, Haike; Bernhard, Helga; Uckert, Wolfgang

    2013-01-01

    The cancer-testis antigen NY-ESO-1 has been used as a target for different immunotherapies like vaccinations and adoptive transfer of antigen-specific cytotoxic T cells, as it is expressed in various tumor types and has limited expression in normal cells. The in vitro generation of T cells with defined antigen specificity by T cell receptor (TCR) gene transfer is an established method to create cells for immunotherapy. However, an extensive characterization of TCR which are candidates for treatment of patients is crucial for successful therapies. The TCR has to be efficiently expressed, their affinity to the desired antigen should be high enough to recognize low amounts of endogenously processed peptides on tumor cells, and the TCR should not be cross-reactive to other antigens. We characterized three NY-ESO-1 antigen-reactive cytotoxic T lymphocyte clones which were generated by different approaches of T cell priming (autologous, allogeneic), and transferred their TCR into donor T cells for more extensive evaluations. Although one TCR most efficiently bound MHC-multimers loaded with NY-ESO-1 peptide, T cells expressing this transgenic TCR were not able to recognize endogenously processed antigen. A second TCR recognized HLA-A2 independent of the bound peptide beside its much stronger recognition of NY-ESO-1 bound to HLA-A2. A third TCR displayed an intermediate but peptide-specific performance in all functional assays and, therefore, is the most promising candidate TCR for further clinical development. Our data indicate that multiple parameters of TCR gene-modified T cells have to be evaluated to identify an optimal TCR candidate for adoptive therapy. PMID:22907642

  5. B lymphocytes as direct antigen-presenting cells for anti-tumor DNA vaccines

    PubMed Central

    Colluru, Viswa Teja; McNeel, Douglas G.

    2016-01-01

    In spite of remarkable preclinical efficacy, DNA vaccination has demonstrated low immunogenicity in humans. While efforts have focused on increasing cross-presentation of DNA-encoded antigens, efforts to increase DNA vaccine immunogenicity by targeting direct presentation have remained mostly unexplored. In these studies, we compared the ability of different APCs to present antigen to T cells after simple co-culture with plasmid DNA. We found that human primary peripheral B lymphocytes, and not monocytes or in vitro derived dendritic cells (DCs), were able to efficiently encode antigen mRNA and expand cognate tumor antigen-specific CD8 T cells ex vivo. Similarly, murine B lymphocytes co-cultured with plasmid DNA, and not DCs, were able to prime antigen-specific T cells in vivo. Moreover, B lymphocyte-mediated presentation of plasmid antigen led to greater Th1-biased immunity and was sufficient to elicit an anti-tumor effect in vivo. Surprisingly, increasing plasmid presentation by B cells, and not cross presentation of peptides by DCs, further augmented traditional plasmid vaccination. Together, these data suggest that targeting plasmid DNA to B lymphocytes, for example through transfer of ex vivo plasmidloaded B cells, may be novel means to achieve greater T cell immunity from DNA vaccines. PMID:27661128

  6. Multiple antigen-presenting system (MAPS) to induce comprehensive B- and T-cell immunity

    PubMed Central

    Zhang, Fan; Lu, Ying-Jie; Malley, Richard

    2013-01-01

    Vaccines are among the most effective approaches to prevent and control many infectious diseases. Because of safety and reproducibility concerns, whole-cell vaccines (WCVs), made from live or killed microorganisms and including hundreds of antigenic components, have been mostly replaced by acellular or subunit vaccines composed of well-defined, purified antigen components. The efficacy of acellular vaccines is inferior to that of WCVs, however, for two major reasons: limited antigen diversity and reduced immunogenicity, especially in a lack of activation of antigen-specific T-cell immunity, which plays an important role in protection against mucosal and intracellular pathogens. Here we present the multiple antigen-presenting system (MAPS), which enables the creation of a macromolecular complex that mimics the properties of WCVs by integrating various antigen components, including polysaccharides and proteins, in the same construct and that induces multipronged immune responses, including antibody, Th1, and Th17 responses. Using antigens from various pathogens (Streptococcus pneumoniae, Salmonella typhi, and Mycobacterium tuberculosis), we demonstrate the versatility of the MAPS system and its feasibility for the design of unique defined-structure subunit vaccines to confer comprehensive protection via multiple immune mechanisms. Moreover, MAPS can serve as a tool for structure-activity analysis of cellular immunogens. PMID:23898212

  7. Skin-Resident Antigen-Presenting Cells: Instruction Manual for Vaccine Development

    PubMed Central

    Fehres, Cynthia M.; Garcia-Vallejo, Juan J.; Unger, Wendy W. J.; van Kooyk, Yvette

    2013-01-01

    The induction of antigen-specific effector T cells is driven by proper antigen presentation and co-stimulation by dendritic cells (DCs). For this reason strategies have been developed to instruct DCs for the induction of CD4+ and CD8+ T cell responses. Since DCs are localized, amongst other locations, in peripheral tissues such as the skin, new vaccines are aiming at targeting antigens to DCs in situ. Optimal skin-DC targeting in combination with adequate adjuvant delivery facilitates DC maturation and migration to draining lymph nodes and enhances antigen cross-presentation and T cell priming. In this review we describe what DC subsets populate the human skin, as well as current vaccination strategies based on targeting strategies and alternative administration for the induction of robust long-lived anti-cancer effector T cells. PMID:23801994

  8. How B cells capture, process and present antigens: a crucial role for cell polarity.

    PubMed

    Yuseff, Maria-Isabel; Pierobon, Paolo; Reversat, Anne; Lennon-Duménil, Ana-Maria

    2013-07-01

    B cells are key components of the adaptive immune response. Their differentiation into either specific memory B cells or antibody-secreting plasma cells is a consequence of activation steps that involve the processing and presentation of antigens. The engagement of B cell receptors by surface-tethered antigens leads to the formation of an immunological synapse that coordinates cell signalling events and that promotes antigen uptake for presentation on MHC class II molecules. In this Review, we discuss membrane trafficking and the associated molecular mechanisms that are involved in antigen extraction and processing at the B cell synapse, and we highlight how B cells use cell polarity to coordinate the complex events that ultimately lead to efficient humoral responses.

  9. Destructive cleavage of antigenic peptides either by the immunoproteasome or by the standard proteasome results in differential antigen presentation.

    PubMed

    Chapiro, Jacques; Claverol, Stéphane; Piette, Fanny; Ma, Wenbin; Stroobant, Vincent; Guillaume, Benoît; Gairin, Jean-Edouard; Morel, Sandra; Burlet-Schiltz, Odile; Monsarrat, Bernard; Boon, Thierry; Van den Eynde, Benoît J

    2006-01-15

    The immunoproteasome (IP) is usually viewed as favoring the production of antigenic peptides presented by MHC class I molecules, mainly because of its higher cleavage activity after hydrophobic residues, referred to as the chymotrypsin-like activity. However, some peptides have been found to be better produced by the standard proteasome. The mechanism of this differential processing has not been described. By studying the processing of three tumor antigenic peptides of clinical interest, we demonstrate that their differential processing mainly results from differences in the efficiency of internal cleavages by the two proteasome types. Peptide gp100(209-217) (ITDQVPSFV) and peptide tyrosinase369-377 (YMDGTMSQV) are destroyed by the IP, which cleaves after an internal hydrophobic residue. Conversely, peptide MAGE-C2(336-344) (ALKDVEERV) is destroyed by the standard proteasome by internal cleavage after an acidic residue, in line with its higher postacidic activity. These results indicate that the IP may destroy some antigenic peptides due to its higher chymotrypsin-like activity, rather than favor their production. They also suggest that the sets of peptides produced by the two proteasome types differ more than expected. Considering that mature dendritic cells mainly contain IPs, our results have implications for the design of immunotherapy strategies.

  10. Angiotensin-converting enzyme affects the presentation of MHC class II antigens.

    PubMed

    Zhao, Tuantuan; Bernstein, Kenneth E; Fang, Jianmin; Shen, Xiao Z

    2017-07-01

    Antigen processing and presentation through the MHC class II pathway is critical for activating T helper cells. Angiotensin-converting enzyme (ACE) is a carboxyl peptidase expressed by antigen-presenting cells. By analysis of ACE null (knockout), wild-type, and ACE-overexpressing (ACE10) mice and the antigen-presenting cells derived from these mice, we found that ACE has a physiological role in the processing of peptides for MHC class II presentation. The efficiency of presenting MHC class II epitopes from ovalbumin (OVA) and hen egg lysosome is markedly affected by cellular ACE levels. Mice overexpressing ACE in myeloid cells have a much more vigorous CD4(+) T-cell and antibody response when immunized with OVA. ACE is present in the endosomal pathway where MHC class II peptide processing and loading occur. The efficiency of MHC class II antigen presentation can be altered by ACE overexpression or ACE pharmacological inhibition. Thus, ACE is a dynamic participant in processing MHC class II peptides. Manipulation of ACE expression by antigen-presenting cells may prove to be a novel strategy to alter the immune response.

  11. Constraints in antigen presentation severely restrict T cell recognition of the allogeneic fetus

    PubMed Central

    Erlebacher, Adrian; Vencato, Daniela; Price, Kelly A.; Zhang, Dorothy; Glimcher, Laurie H.

    2007-01-01

    How the fetus escapes rejection by the maternal immune system remains one of the major unsolved questions in transplantation immunology. Using a system to visualize both CD4+ and CD8+ T cell responses during pregnancy in mice, we find that maternal T cells become aware of the fetal allograft exclusively through “indirect” antigen presentation, meaning that T cell engagement requires the uptake and processing of fetal/placental antigen by maternal APCs. This reliance on a relatively minor allorecognition pathway removes a major threat to fetal survival, since it avoids engaging the large number of T cells that typically drive acute transplant rejection through their ability to directly interact with foreign MHC molecules. Furthermore, CD8+ T cells that indirectly recognize fetal/placental antigen undergo clonal deletion without priming for cytotoxic effector function and cannot induce antigen-specific fetal demise even when artificially activated. Antigen presentation commenced only at mid-gestation, in association with the endovascular invasion of placental trophoblasts and the hematogenous release of placental debris. Our results suggest that limited pathways of antigen presentation, in conjunction with tandem mechanisms of immune evasion, contribute to the unique immunological status of the fetus. The pronounced degree of T cell ignorance of the fetus also has implications for the pathophysiology of immune-mediated early pregnancy loss. PMID:17446933

  12. Y. enterocolitica translocated Yops impair stimulation of T-cells by antigen presenting cells.

    PubMed

    Kramer, Uwe; Wiedig, Carolin A

    2005-09-15

    As T helper cells play a crucial role in the defense of the mouse immune system against Yersinia enterocolitica, an effective subversion strategy for the pathogen would be the inhibition of T-cell activation. In this study, we investigated whether Y. enterocolitica impairs this process on the level of antigen presentation. For this purpose, we used T-cells to measure the antigen presentation capacity of dendritic cells after they had been incubated with different types of Yersinia mutants. We could show that Y. enterocolitica impairs the processing of antigens by dendritic cells, that this effect is dependent on factors translocated by the pathogenicity-plasmid-encoded type III secretion system and that the most important factor appears to be YopP. The YopP effect is partly mediated by the killing of APCs, but in addition to this there appears to be an alternative way of action that results in the inhibition of antigen processing. The YopP effect is not mediated by soluble factors. In contrast to antigen processing, antigen presentation was only weakly affected by pathogenicity plasmid encoded factors in dendritic cells, but obviously in A20.J B-cells.

  13. Ubiquitinated Proteins Isolated From Tumor Cells Are Efficient Substrates for Antigen Cross-Presentation.

    PubMed

    Yu, Guangjie; Moudgil, Tarsem; Cui, Zhihua; Mou, Yongbin; Wang, Lixin; Fox, Bernard A; Hu, Hong-Ming

    2017-03-31

    We have previously shown that inhibition of the proteasome causes defective ribosomal products to be shunted into autophagosomes and subsequently released from tumor cells as defective ribosomal products in Blebs (DRibbles). These DRibbles serve as an excellent source of antigens for cross-priming of tumor-specific T cells. Here, we examine the role of ubiquitinated proteins (Ub-proteins) in this pathway. Using purified Ub-proteins from tumor cells that express endogenous tumor-associated antigen or exogenous viral antigen, we tested the ability of these proteins to stimulate antigen-specific T-cell responses, by activation of monocyte-derived dendritic cells generated from human peripheral blood mononuclear cells. Compared with total cell lysates, we found that purified Ub-proteins from both a gp100-specific melanoma cell line and from a lung cancer cell line expressing cytomegalovirus pp65 antigen produced a significantly higher level of IFN-γ in gp100- or pp65-specific T cells, respectively. In addition, Ub-proteins from an allogeneic tumor cell line could be used to stimulate tumor-infiltrating lymphocytes isolated and expanded from non-small cell lung cancer patients. These results establish that Ub-proteins provide a relevant source of antigens for cross-priming of antitumor immune responses in a variety of settings, including endogenous melanoma and exogenous viral antigen presentation, as well as antigen-specific tumor-infiltrating lymphocytes. Thus, ubiquitin can be used as an affinity tag to enrich for unknown tumor-specific antigens from tumor cell lysates to stimulate tumor-specific T cells ex vivo or to be used as vaccines to target short-lived proteins.

  14. Redirecting soluble antigen for MHC class I cross-presentation during phagocytosis.

    PubMed

    Hari, Aswin; Ganguly, Anutosh; Mu, Libing; Davis, Shevaun P; Stenner, Melanie D; Lam, Raymond; Munro, Fay; Namet, Inana; Alghamdi, Enaam; Fürstenhaupt, Tobias; Dong, Wei; Detampel, Pascal; Shen, Lian Jun; Amrein, Matthias W; Yates, Robin M; Shi, Yan

    2015-02-01

    Peptides presented by MHC class I molecules are mostly derived from proteins synthesized by the antigen-presenting cell itself, while peptides presented by MHC class II molecules are predominantly from materials acquired by endocytosis. External antigens can also be presented by MHC class I molecules in a process referred to as cross-presentation. Here, we report that mouse dendritic cell (DC) engagement to a phagocytic target alters endocytic processing and inhibits the proteolytic activities. During phagocytosis, endosome maturation is delayed, shows less progression toward the lysosome, and the endocytosed soluble antigen is targeted for MHC class I cross-presentation. The antigen processing in these arrested endosomes is under the control of NAPDH oxidase associated ROS. We also show that cathepsin S is responsible for the generation of the MHC class I epitope. Taken together, our results suggest that in addition to solid structure uptake, DC phagocytosis simultaneously modifies the kinetics of endosomal trafficking and maturation. As a consequence, external soluble antigens are targeted into the MHC class I cross-presentation pathway.

  15. In vivo requirement for Atg5 in antigen presentation by dendritic cells.

    PubMed

    Lee, Heung Kyu; Mattei, Lisa M; Steinberg, Benjamin E; Alberts, Philipp; Lee, Yun Hee; Chervonsky, Alexander; Mizushima, Noboru; Grinstein, Sergio; Iwasaki, Akiko

    2010-02-26

    Autophagy is known to be important in presentation of cytosolic antigens on MHC class II (MHC II). However, the role of autophagic process in antigen presentation in vivo is unclear. Mice with dendritic cell (DC)-conditional deletion in Atg5, a key autophagy gene, showed impaired CD4(+) T cell priming after herpes simplex virus infection and succumbed to rapid disease. The most pronounced defect of Atg5(-/-) DCs was the processing and presentation of phagocytosed antigens containing Toll-like receptor stimuli for MHC class II. In contrast, cross-presentation of peptides on MHC I was intact in the absence of Atg5. Although induction of metabolic autophagy did not enhance MHC II presentation, autophagic machinery was required for optimal phagosome-to-lysosome fusion and subsequent processing of antigen for MHC II loading. Thus, our study revealed that DCs utilize autophagic machinery to optimally process and present extracellular microbial antigens for MHC II presentation. Copyright 2010 Elsevier Inc. All rights reserved.

  16. Redirecting soluble antigen for MHC class I cross-presentation during phagocytosis

    PubMed Central

    Hari, Aswin; Ganguly, Anutosh; Mu, Libing; Davis, Shevaun P.; Stenner, Melanie D.; Lam, Raymond; Munro, Fay; Namet, Inana; Alghamdi, Enaam; Fürstenhaupt, Tobias; Dong, Wei; Detampel, Pascal; Shen, Lian Jun; Amrein, Matthias W.; Yates, Robin M.; Shi, Yan

    2014-01-01

    Peptides presented by MHC class I molecules are derived mostly from proteins synthesized by the antigen-presenting cell itself, while peptides presented by MHC class II molecules are derived predominantly from materials acquired by endocytosis. External antigens can also be presented by MHC class I molecules in a process referred to as cross-presentation. We report that mouse dendritic cell engagement of a phagocytic target alters endocytic processing and inhibits their proteolytic activities. During phagocytosis, endosome maturation is delayed, shows less progression towards the lysosome, and the endocytosed soluble antigen is targeted for MHC class I cross-presentation. The antigen processing in these arrested endosomes is under the control of NAPDH oxidase associated ROS. We also show that cathepsin S is responsible for the generation of the MHC class I epitope. Our results suggest that in addition to solid structure uptake, DC phagocytosis simultaneously modifies the kinetics of endosomal trafficking and maturation. As a consequence, external soluble antigens are targeted into the MHC class I cross-presentation pathway. PMID:25378230

  17. Triazole-linked fluorescent bisboronic acid capable of selective recognition of the Lewis Y antigen.

    PubMed

    Wang, Yan'en; Rong, Ruixue; Chen, Hua; Zhu, Mengyuan; Wang, Binghe; Li, Xiaoliu

    2017-05-01

    Cell surface carbohydrates of the Lewis blood group antigens, Lewis X (Le(x)), Lewis Y (Le(y)), Lewis A (Le(a)), and their sialylated derivatives, such as sialy Lewis X (sLe(x)) and sialy Lewis A (sLe(a)), play important roles in various recognition processes. These cell surface carbohydrates have also been associated with the development and progression of many types of cancers. Recently, we synthesized four anthracene-based fluorescent bisboronic acid sensors (compounds 2a-d) linked by 'click' chemistry with tethers of different lengths to match the epitope of various Lewis group of sugars. Among the four compounds, 2a appears to have both high sensitivity and selectivity for Le(y) among other carbohydrate antigens. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Role of metalloproteases in vaccinia virus epitope processing for transporter associated with antigen processing (TAP)-independent human leukocyte antigen (HLA)-B7 class I antigen presentation.

    PubMed

    Lorente, Elena; García, Ruth; Mir, Carmen; Barriga, Alejandro; Lemonnier, François A; Ramos, Manuel; López, Daniel

    2012-03-23

    The transporter associated with antigen processing (TAP) translocates the viral proteolytic peptides generated by the proteasome and other proteases in the cytosol to the endoplasmic reticulum lumen. There, they complex with nascent human leukocyte antigen (HLA) class I molecules, which are subsequently recognized by the CD8(+) lymphocyte cellular response. However, individuals with nonfunctional TAP complexes or tumor or infected cells with blocked TAP molecules are able to present HLA class I ligands generated by TAP-independent processing pathways. Herein, using a TAP-independent polyclonal vaccinia virus-polyspecific CD8(+) T cell line, two conserved vaccinia-derived TAP-independent HLA-B*0702 epitopes were identified. The presentation of these epitopes in normal cells occurs via complex antigen-processing pathways involving the proteasome and/or different subsets of metalloproteinases (amino-, carboxy-, and endoproteases), which were blocked in infected cells with specific chemical inhibitors. These data support the hypothesis that the abundant cellular proteolytic systems contribute to the supply of peptides recognized by the antiviral cellular immune response, thereby facilitating immunosurveillance. These data may explain why TAP-deficient individuals live normal life spans without any increased susceptibility to viral infections.

  19. Role of Metalloproteases in Vaccinia Virus Epitope Processing for Transporter Associated with Antigen Processing (TAP)-independent Human Leukocyte Antigen (HLA)-B7 Class I Antigen Presentation*

    PubMed Central

    Lorente, Elena; García, Ruth; Mir, Carmen; Barriga, Alejandro; Lemonnier, François A.; Ramos, Manuel; López, Daniel

    2012-01-01

    The transporter associated with antigen processing (TAP) translocates the viral proteolytic peptides generated by the proteasome and other proteases in the cytosol to the endoplasmic reticulum lumen. There, they complex with nascent human leukocyte antigen (HLA) class I molecules, which are subsequently recognized by the CD8+ lymphocyte cellular response. However, individuals with nonfunctional TAP complexes or tumor or infected cells with blocked TAP molecules are able to present HLA class I ligands generated by TAP-independent processing pathways. Herein, using a TAP-independent polyclonal vaccinia virus-polyspecific CD8+ T cell line, two conserved vaccinia-derived TAP-independent HLA-B*0702 epitopes were identified. The presentation of these epitopes in normal cells occurs via complex antigen-processing pathways involving the proteasome and/or different subsets of metalloproteinases (amino-, carboxy-, and endoproteases), which were blocked in infected cells with specific chemical inhibitors. These data support the hypothesis that the abundant cellular proteolytic systems contribute to the supply of peptides recognized by the antiviral cellular immune response, thereby facilitating immunosurveillance. These data may explain why TAP-deficient individuals live normal life spans without any increased susceptibility to viral infections. PMID:22298786

  20. MHC-restricted antigen presentation and recognition: constraints on gene, recombinant and peptide vaccines in humans.

    PubMed

    Cunha-Neto, E

    1999-02-01

    The target of any immunization is to activate and expand lymphocyte clones with the desired recognition specificity and the necessary effector functions. In gene, recombinant and peptide vaccines, the immunogen is a single protein or a small assembly of epitopes from antigenic proteins. Since most immune responses against protein and peptide antigens are T-cell dependent, the molecular target of such vaccines is to generate at least 50-100 complexes between MHC molecule and the antigenic peptide per antigen-presenting cell, sensitizing a T cell population of appropriate clonal size and effector characteristics. Thus, the immunobiology of antigen recognition by T cells must be taken into account when designing new generation peptide- or gene-based vaccines. Since T cell recognition is MHC-restricted, and given the wide polymorphism of the different MHC molecules, distinct epitopes may be recognized by different individuals in the population. Therefore, the issue of whether immunization will be effective in inducing a protective immune response, covering the entire target population, becomes an important question. Many pathogens have evolved molecular mechanisms to escape recognition by the immune system by variation of antigenic protein sequences. In this short review, we will discuss the several concepts related to selection of amino acid sequences to be included in DNA and peptide vaccines.

  1. Antigen presentation by non-immune B-cell hybridoma clones: presentation of synthetic antigenic sites reveals clones that exhibit no specificity and clones that present only one epitope

    NASA Technical Reports Server (NTRS)

    Cohly, H. H.; Morrison, D. R.; Atassi, M. Z.

    1989-01-01

    Recently, we reported the preparation and antigen-presenting properties of hybridoma B-cell clones obtained after fusing non-secreting, non-antigen presenting Balb/c 653-myeloma cells with non-immune SJL spleen cells. It was found that antigen presentation at the clonal level can be specific or non-specific, depending on the particular B-cell clone. In the present work, one specific and one general presenter B-cell clones were tested for their epitope presentation ability to SJL T-cells that were specific to lysozyme or myoglobin. B-cell clone A1G12, a general presenter which presented both lysozyme and myoglobin to their respective T-cell lines, was found to present all five myoglobin epitopes while clone A1L16, a lysozyme specific presenter presented only one of the three epitopes of lysozyme. The latter reveals a hitherto unknown submolecular specificity (to a given epitope within a protein) for antigen presenting cells at the clonal level. Therefore, the specificity of T-cell recognition does not only derive from the T-cell but may also be dependent on the epitope specificity of the antigen-presenting B-cell.

  2. Antigen presentation by non-immune B-cell hybridoma clones: presentation of synthetic antigenic sites reveals clones that exhibit no specificity and clones that present only one epitope

    NASA Technical Reports Server (NTRS)

    Cohly, H. H.; Morrison, D. R.; Atassi, M. Z.

    1989-01-01

    Recently, we reported the preparation and antigen-presenting properties of hybridoma B-cell clones obtained after fusing non-secreting, non-antigen presenting Balb/c 653-myeloma cells with non-immune SJL spleen cells. It was found that antigen presentation at the clonal level can be specific or non-specific, depending on the particular B-cell clone. In the present work, one specific and one general presenter B-cell clones were tested for their epitope presentation ability to SJL T-cells that were specific to lysozyme or myoglobin. B-cell clone A1G12, a general presenter which presented both lysozyme and myoglobin to their respective T-cell lines, was found to present all five myoglobin epitopes while clone A1L16, a lysozyme specific presenter presented only one of the three epitopes of lysozyme. The latter reveals a hitherto unknown submolecular specificity (to a given epitope within a protein) for antigen presenting cells at the clonal level. Therefore, the specificity of T-cell recognition does not only derive from the T-cell but may also be dependent on the epitope specificity of the antigen-presenting B-cell.

  3. Exosomes function in antigen presentation during an in vivo Mycobacterium tuberculosis infection

    PubMed Central

    Smith, Victoria L.; Cheng, Yong; Bryant, Barry R.; Schorey, Jeffrey S.

    2017-01-01

    Mycobacterium tuberculosis-infected macrophages and dendritic cells are limited in their ability to present antigen to CD4+ T cells suggesting that other mechanism of antigen presentation are driving the robust T cell response observed during an M. tuberculosis infection. These mechanisms could include antigens present in apoptotic bodies, necrotic debris, exosomes or even release of non-vesicular antigen from infected cells. However, there is limited data to support any of these mechanisms as important in driving T cell activation in vivo. In the present study we use Rab27a-deficient mice which show diminished trafficking of mycobacterial components to exosomes as well as M. tuberculosis strains that express recombinant proteins which traffic or fail to traffic to exosomes. We observed that exosomes released during a mouse M. tuberculosis infection contribute significantly to its T cell response. These finding imply that exosomes function to promote T cell immunity during a bacterial infection and are an important source of extracellular antigen. PMID:28262829

  4. Killer artificial antigen-presenting cells: the synthetic embodiment of a 'guided missile'.

    PubMed

    Schütz, Christian; Oelke, Mathias; Schneck, Jonathan P; Mackensen, Andreas; Fleck, Martin

    2010-07-01

    At present, the treatment of T-cell-dependent autoimmune diseases relies exclusively on strategies leading to nonspecific suppression of the immune systems causing a substantial reduced ability to control concomitant infections or malignancies. Furthermore, long-term treatment with most drugs is accompanied by several serious adverse effects and does not consequently result in cure of the primary immunological malfunction. By contrast, antigen-specific immunotherapy offers the potential to achieve the highest therapeutic efficiency in accordance with minimal adverse effects. Therefore, several studies have been performed utilizing antigen-presenting cells specifically engineered to deplete allo- or antigen-specific T cells ('guided missiles'). Many of these strategies take advantage of the Fas/Fas ligand signaling pathway to efficiently induce antigen-presenting cell-mediated apoptosis in targeted T cells. In this article, we discuss the advantages and shortcomings of a novel non-cell-based 'killer artificial antigen-presenting cell' strategy, developed to overcome obstacles related to current cell-based approaches for the treatment of T-cell-mediated autoimmunity.

  5. Killer artificial antigen-presenting cells: the synthetic embodiment of a ‘guided missile’

    PubMed Central

    Schütz, Christian; Oelke, Mathias; Schneck, Jonathan P; Mackensen, Andreas; Fleck, Martin

    2010-01-01

    At present, the treatment of T-cell-dependent autoimmune diseases relies exclusively on strategies leading to nonspecific suppression of the immune systems causing a substantial reduced ability to control concomitant infections or malignancies. Furthermore, long-term treatment with most drugs is accompanied by several serious adverse effects and does not consequently result in cure of the primary immunological malfunction. By contrast, antigen-specific immunotherapy offers the potential to achieve the highest therapeutic efficiency in accordance with minimal adverse effects. Therefore, several studies have been performed utilizing antigen-presenting cells specifically engineered to deplete allo- or antigen-specific T cells (‘guided missiles’). Many of these strategies take advantage of the Fas/Fas ligand signaling pathway to efficiently induce antigen-presenting cell-mediated apoptosis in targeted T cells. In this article, we discuss the advantages and shortcomings of a novel non-cell-based ‘killer artificial antigen-presenting cell’ strategy, developed to overcome obstacles related to current cell-based approaches for the treatment of T-cell-mediated autoimmunity. PMID:20636007

  6. Exosomes function in antigen presentation during an in vivo Mycobacterium tuberculosis infection.

    PubMed

    Smith, Victoria L; Cheng, Yong; Bryant, Barry R; Schorey, Jeffrey S

    2017-03-06

    Mycobacterium tuberculosis-infected macrophages and dendritic cells are limited in their ability to present antigen to CD4+ T cells suggesting that other mechanism of antigen presentation are driving the robust T cell response observed during an M. tuberculosis infection. These mechanisms could include antigens present in apoptotic bodies, necrotic debris, exosomes or even release of non-vesicular antigen from infected cells. However, there is limited data to support any of these mechanisms as important in driving T cell activation in vivo. In the present study we use Rab27a-deficient mice which show diminished trafficking of mycobacterial components to exosomes as well as M. tuberculosis strains that express recombinant proteins which traffic or fail to traffic to exosomes. We observed that exosomes released during a mouse M. tuberculosis infection contribute significantly to its T cell response. These finding imply that exosomes function to promote T cell immunity during a bacterial infection and are an important source of extracellular antigen.

  7. Intracellular Transport Routes for MHC I and Their Relevance for Antigen Cross-Presentation

    PubMed Central

    Adiko, Aimé Cézaire; Babdor, Joel; Gutiérrez-Martínez, Enric; Guermonprez, Pierre; Saveanu, Loredana

    2015-01-01

    Cross-presentation, in which exogenous antigens are presented via MHC I complexes, is involved both in the generation of anti-infectious and anti-tumoral cytotoxic CD8+ T cells and in the maintenance of immune tolerance. While cross-presentation was described almost four decades ago and while it is now established that some dendritic cell (DC) subsets are better than others in processing and cross-presenting internalized antigens, the involved molecular mechanisms remain only partially understood. Some of the least explored molecular mechanisms in cross-presentation concern the origin of cross-presenting MHC I molecules and the cellular compartments where antigenic peptide loading occurs. This review focuses on MHC I molecules and their intracellular trafficking. We discuss the source of cross-presenting MHC I in DCs as well as the role of the endocytic pathway in their recycling from the cell surface. Next, we describe the importance of the TAP peptide transporter for delivering peptides to MHC I during cross-presentation. Finally, we highlight the impact of innate immunity mechanisms on specific antigen cross-presentation mechanisms in which TLR activation modulates MHC I trafficking and TAP localization. PMID:26191062

  8. Estimation of low frequency antigen presenting cells with a novel RELISPOT assay

    PubMed Central

    Dzutsev, Amiran K.; Belyakov, Igor M.; Isakov, Dmitry V.; Gagnon, Susan J.; Margulies, David H.; Berzofsky, Jay A.

    2008-01-01

    Adequate presentation of self and foreign antigens is a key factor for efficient T-cell immunosurveillance against pathogens and tumors. Cells presenting foreign antigens usually comprise a rare population and are difficult to detect even at the peak of infection. Here we demonstrate a CD8+ T-cell-based approach that allows detection of specific antigen-presenting cells (APC) at a frequency of less than 0.0005%. When T cells are in excess, they form rosettes with rare APCs, which appear as single spots in an IFN-γ ELISPOT assay. Using this RELISPOT (Rosette ELISPOT) method we demonstrate the dynamic interplay between CD8 T cells and professional and non-professional APCs following virus challenge. PMID:18294650

  9. Tumor Antigen Cross-Presentation and the Dendritic Cell: Where it All Begins?

    PubMed Central

    McDonnell, Alison M.; Robinson, Bruce W. S.; Currie, Andrew J.

    2010-01-01

    Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that are critical for the generation of effective cytotoxic T lymphocyte (CTL) responses; however, their function and phenotype are often defective or altered in tumor-bearing hosts, which may limit their capacity to mount an effective tumor-specific CTL response. In particular, the manner in which exogenous tumor antigens are acquired, processed, and cross-presented to CD8 T cells by DCs in tumor-bearing hosts is not well understood, but may have a profound effect on antitumor immunity. In this paper, we have examined the role of DCs in the cross-presentation of tumor antigen in terms of their subset, function, migration, and location with the intention of examining the early processes that contribute to the development of an ineffective anti-tumor immune response. PMID:20976125

  10. Multiplexed immunophenotyping of human antigen-presenting cells in whole blood by polychromatic flow cytometry

    PubMed Central

    Fung, Erik; Esposito, Laura; Todd, John A.; Wicker, Linda S.

    2010-01-01

    We describe two modular protocols for immunostaining and multiparameter flow cytometric analysis of major human antigen-presenting cells (dendritic cells, monocytes, B lymphocytes) in minimally manipulated whole blood. Simultaneous detection of up to eight colors is enabled by careful selection and testing of cell-subset-defining monoclonal antibodies (anchor markers) in the appropriate fluorochrome combinations, to demonstrate the quantification of surface expression levels of molecules involved in chemotaxis (e.g. CX3CR1, CCR2), adhesion (e.g. CD11b, CD62L), antigen presentation (e.g. CD83, CD86, CD209) and immune regulation (e.g. CD101) on circulating antigen-presenting cells. Each immunostaining reaction requires as little as 50–100 μl of peripheral whole blood, no density-gradient separation, and the entire procedure from preparation of reagents to flow cytometry can be completed in <5 h. PMID:20134434

  11. Langerhans cells utilize CD1a and langerin to efficiently present nonpeptide antigens to T cells

    PubMed Central

    Hunger, Robert E.; Sieling, Peter A.; Ochoa, Maria Teresa; Sugaya, Makoto; Burdick, Anne E.; Rea, Thomas H.; Brennan, Patrick J.; Belisle, John T.; Blauvelt, Andrew; Porcelli, Steven A.; Modlin, Robert L.

    2004-01-01

    Langerhans cells (LCs) constitute a subset of DCs that initiate immune responses in skin. Using leprosy as a model, we investigated whether expression of CD1a and langerin, an LC-specific C-type lectin, imparts a specific functional role to LCs. LC-like DCs and freshly isolated epidermal LCs presented nonpeptide antigens of Mycobacterium leprae to T cell clones derived from a leprosy patient in a CD1a-restricted and langerin-dependent manner. LC-like DCs were more efficient at CD1a-restricted antigen presentation than monocyte-derived DCs. LCs in leprosy lesions coexpress CD1a and langerin, placing LCs in position to efficiently present a subset of antigens to T cells as part of the host response to human infectious disease. PMID:14991068

  12. A catalytically inactive mutant of the deubiquitylase YOD-1 enhances antigen cross-presentation

    PubMed Central

    Sehrawat, Sharvan; Koenig, Paul-Albert; Kirak, Oktay; Schlieker, Christian; Fankhauser, Manuel

    2013-01-01

    Antigen presenting cells (APCs) that express a catalytically inactive version of the deubiquitylase YOD1 (YOD1-C160S) present exogenous antigens more efficiently to CD8+ T cells, both in vitro and in vivo. Compared with controls, immunization of YOD1-C160S mice led to greater expansion of specific CD8+ T cells and showed improved control of infection with a recombinant γ-herpes virus, MHV-68, engineered to express SIINFEKL peptide, the ligand for the ovalbumin-specific TCR transgenic OT-I cells. Enhanced expansion of specific CD8+ T cells was likewise observed on infection of YOD1-C160S mice with a recombinant influenza A virus expressing SIINFEKL. YOD1-C160S APCs retained antigen longer than did control APCs. Enhanced cross-presentation by YOD1-C160S APCs was transporter associated with antigen processing (TAP1)–independent but sensitive to inclusion of inhibitors of acidification and of the proteasome. The activity of deubiquitylating enzymes may thus help control antigen-specific CD8+ T-cell responses during immunization. PMID:23243279

  13. Pros and Cons of Antigen-Presenting Cell Targeted Tumor Vaccines.

    PubMed

    Goyvaerts, Cleo; Breckpot, Karine

    2015-01-01

    In therapeutic antitumor vaccination, dendritic cells play the leading role since they decide if, how, when, and where a potent antitumor immune response will take place. Since the disentanglement of the complexity and merit of different antigen-presenting cell subtypes, antitumor immunotherapeutic research started to investigate the potential benefit of targeting these subtypes in situ. This review will discuss which antigen-presenting cell subtypes are at play and how they have been targeted and finally question the true meaning of targeting antitumor-based vaccines.

  14. Pros and Cons of Antigen-Presenting Cell Targeted Tumor Vaccines

    PubMed Central

    Goyvaerts, Cleo; Breckpot, Karine

    2015-01-01

    In therapeutic antitumor vaccination, dendritic cells play the leading role since they decide if, how, when, and where a potent antitumor immune response will take place. Since the disentanglement of the complexity and merit of different antigen-presenting cell subtypes, antitumor immunotherapeutic research started to investigate the potential benefit of targeting these subtypes in situ. This review will discuss which antigen-presenting cell subtypes are at play and how they have been targeted and finally question the true meaning of targeting antitumor-based vaccines. PMID:26583156

  15. Specific antigen targeting to surface IgE and IgG on mouse bone marrow-derived mast cells enhances efficiency of antigen presentation.

    PubMed Central

    Tkaczyk, C; Viguier, M; Boutin, Y; Frandji, P; David, B; Hébert, J; Mécheri, S

    1998-01-01

    The discovery that bone marrow-derived mast cells can express major histocompatibility complex class II molecules and act as antigen-presenting cells prompted us to evaluate this function when antigen is internalized through fluid-phase endocytosis or via specific uptake by using IgG and IgE antibodies. This study was performed using a specific T-cell hybridoma developed against Lol p 1, the major allergen of grass pollen Lolium perenne. Expression of Fc gamma R and Fc epsilon RI by mast cells led us to investigate the influence of IgG- and IgE-targeted antigen on the antigen-presenting function of mast cells. Internalization of Lol p 1 through different specific IgG monoclonal antibodies (mAb) resulted in the activation of Lol p 1-specific T-cell hybridoma at concentrations about 100-fold less than that required for T-cell stimulation by uncomplexed antigen. IgE-complexed Lol p 1, which facilitates trapping of antigen by mast cells, induced an accelerated and more efficient antigen-presenting capacity of mast cells than that obtained with uncomplexed antigen. However, aggregation of anti-dinitrophenyl (DNP) IgE mAb by the irrelevant antigen DNP-human serum albumin did not substantially increase the capacity of mast cells to present Lol p 1 to T cells. This suggests that the mere aggregation of Fc epsilon RI is not sufficient for enhanced antigen presentation mediated by IgE. Tissue distribution and strategic location of mast cells at the mucosal barriers and their capacity to process the antigen through efficient fluid-phase pinocytosis as well as IgG- and IgE-dependent targeting of antigens provide mast cells with a prominent role in immune surveillance. Images Figure 1 PMID:9767412

  16. Efficient major histocompatibility complex class I presentation of exogenous antigen upon phagocytosis by macrophages.

    PubMed Central

    Kovacsovics-Bankowski, M; Clark, K; Benacerraf, B; Rock, K L

    1993-01-01

    Antigens in extracellular fluids can be processed and presented with major histocompatibility complex (MHC) class I molecules by a subset of antigen presenting cells (APCs). Chicken egg ovalbumin (Ova) linked to beads was presented with MHC class I molecules by these cells up to 10(4)-fold more efficiently than soluble Ova. This enhanced presentation was observed with covalently or noncovalently linked Ova and with beads of different compositions. A key parameter in the activity of these conjugates was the size of the beads. The APC that is responsible for this form of presentation is a macrophage. These cells internalize the antigen constructs through phagocytosis, since cytochalasin B inhibited presentation. Processing of the antigen and association with MHC class I molecules appears to occur intracellularly as presentation was observed under conditions where there was no detectable release of peptides into the extracellular fluids. When injected in vivo in C57BL/6 mice, Ova-beads, but not soluble Ova, primed CD4- CD8+ cytotoxic T lymphocytes (CTLs). Similar results were obtained in BALB/c mice immunized with beta-galactosidase-beads. The implications of these findings for development of nonliving vaccines that stimulate CTL immunity are discussed. PMID:8506338

  17. Serum proteases alter the antigenicity of peptides presented by class I major histocompatibility complex molecules.

    PubMed Central

    Falo, L D; Colarusso, L J; Benacerraf, B; Rock, K L

    1992-01-01

    Any effect of serum on the antigenicity of peptides is potentially relevant to their use as immunogens in vivo. Here we demonstrate that serum contains distinct proteases that can increase or decrease the antigenicity of peptides. By using a functional assay, we show that a serum component other than beta 2-microglobulin enhances the presentation of ovalbumin peptides produced by cyanogen bromide cleavage. Three features of this serum activity implicate proteolysis: it is temperature dependent, it results in increased antigenicity in a low molecular weight peptide fraction, and it is inhibited by the protease inhibitor leupeptin. Conversely, presentation of the synthetic peptide OVA-(257-264) is inhibited by serum. This inhibition is unaffected by leupeptin but is blocked by bestatin, a protease inhibitor with distinct substrate specificities. Implications for peptide-based vaccine design and immunotherapy are discussed. PMID:1518868

  18. No Major Role for Insulin-Degrading Enzyme in Antigen Presentation by MHC Molecules

    PubMed Central

    Hsu, Hsiang-Ting; Burgevin, Anne; Guénette, Suzanne; Moser, Anna; van Endert, Peter

    2014-01-01

    Antigen presentation by MHC class I molecules requires degradation of epitope source proteins in the cytosol. Although the preeminent role of the proteasome is clearly established, evidence suggesting a significant role for proteasome-independent generation of class I ligands has been reported repeatedly. However, an enzyme responsible for such a role has not been identified. Recently insulin-degrading enzyme (IDE) was shown to produce an antigenic peptide derived from the tumor antigen MAGE-A3 in an entirely proteasome-independent manner, raising the question of the global impact of IDE in MHC class I antigen processing. Here we report that IDE knockdown in human cell lines, or knockout in two different mouse strains, has no effect on cell surface expression of various MHC class I molecules, including allomorphs such as HLA-A3 and HLA-B27 suggested to be loaded in an at least a partly proteasome-independent manner. Moreover, reduced or absent IDE expression does not affect presentation of five epitopes including epitopes derived from beta amyloid and proinsulin, two preferred IDE substrates. Thus, IDE does not play a major role in MHC class I antigen processing, confirming the dominant and almost exclusive role of the proteasome in cytosolic production of MHC class I ligands. PMID:24516642

  19. Dendritic Cells Are the Major Antigen Presenting Cells in Inflammatory Lesions of Murine Mycoplasma Respiratory Disease

    PubMed Central

    Sun, Xiangle; Jones, Harlan P.; Dobbs, Nicole; Bodhankar, Sheetal; Simecka, Jerry W.

    2013-01-01

    Mycoplasmas cause chronic respiratory diseases in animals and humans, and to date, development of vaccines have been problematic. Using a murine model of mycoplasma pneumonia, lymphocyte responses, specifically T cells, were shown to confer protection as well as promote immunopathology in mycoplasma disease. Because T cells play such a critical role, it is important to define the role of antigen presenting cells (APC) as these cells may influence either exacerbation of mycoplasma disease pathogenesis or enhancement of protective immunity. The roles of APC, such as dendritic cells and/or macrophages, and their ability to modulate adaptive immunity in mycoplasma disease are currently unknown. Therefore, the purpose of this study was to identify individual pulmonary APC populations that may contribute to the activation of T cell responses during mycoplasma disease pathogenesis. The present study indeed demonstrates increasing numbers of CD11c− F4/80+ cells, which contain macrophages, and more mature/activated CD11c+ F4/80− cells, containing DC, in the lungs after infection. CD11c− F4/80+ macrophage-enriched cells and CD11c+ F4/80− dendritic cell-enriched populations showed different patterns of cytokine mRNA expression, supporting the idea that these cells have different impacts on immunity in response to infection. In fact, DC containing CD11c+ F4/80− cell populations from the lungs of infected mice were most capable of stimulating mycoplasma-specific CD4+ Th cell responses in vitro. In vivo, these CD11c+F4/80− cells were co-localized with CD4+ Th cells in inflammatory infiltrates in the lungs of mycoplasma-infected mice. Thus, CD11c+F4/80− dendritic cells appear to be the major APC population responsible for pulmonary T cell stimulation in mycoplasma-infected mice, and these dendritic cells likely contribute to responses impacting disease pathogenesis. PMID:23390557

  20. Estimating Heat and Mass Transfer Processes in Green Roof Systems: Current Modeling Capabilities and Limitations (Presentation)

    SciTech Connect

    Tabares Velasco, P. C.

    2011-04-01

    This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'specialized roofing systems that support vegetation growth on rooftops.'

  1. Suboptimal antigen presentation contributes to virulence of M. tuberculosis in vivo1

    PubMed Central

    Grace, Patricia S.; Ernst, Joel D.

    2015-01-01

    Mycobacterium tuberculosis commonly causes persistent or chronic infection, despite development of antigen-specific CD4 T cell responses. We hypothesized that M. tuberculosis evades elimination by CD4 T cell responses by manipulating MHC class II antigen presentation and CD4 T cell activation, and tested this hypothesis by comparing activation of Ag85B-specific CD4 T cell responses to M. tuberculosis and M. bovis BCG Pasteur in vivo and in vitro. We found that, while M. tuberculosis persists in lungs of immunocompetent mice, M. bovis BCG is cleared, and clearance is T cell dependent. We further discovered that M. tuberculosis-infected macrophages and dendritic cells activate Ag85B-specific CD4 T cells less efficiently and less effectively than do BCG-infected cells, in vivo and in vitro, despite higher production and secretion of Ag85B by M. tuberculosis. During BCG infection, activation of Ag85B-specific CD4 T cells requires fewer infected dendritic cells, and fewer antigen-producing bacteria than during M. tuberculosis infection. When dendritic cells containing equivalent numbers of M. tuberculosis or BCG were transferred to mice, BCG-infected cells activated proliferation of more Ag85B-specific CD4 T cells than did M. tuberculosis-infected cells. Differences in Ag85B-specific CD4 T cell activation were attributable to differential antigen presentation, rather than differential expression of costimulatory or inhibitory molecules. These data indicate that subpoptimal antigen presentation contributes to persistent infection, and that limiting antigen presentation is a virulence property of M. tuberculosis. PMID:26573837

  2. Uptake and presentation of exogenous antigen and presentation of endogenously produced antigen by skin dendritic cells represent equivalent pathways for the priming of cellular immune responses following biolistic DNA immunization.

    PubMed

    Sudowe, Stephan; Dominitzki, Sabine; Montermann, Evelyn; Bros, Matthias; Grabbe, Stephan; Reske-Kunz, Angelika B

    2009-09-01

    Gene gun-mediated biolistic DNA vaccination with beta-galactosidase (betaGal)-encoding plasmid vectors efficiently modulated antigen-induced immune responses in an animal model of type I allergy, including the inhibition of immunoglobulin E (IgE) production. Here we show that CD4(+) as well as CD8(+) T cells from mice biolistically transfected with a plasmid encoding betaGal under the control of the fascin promoter (pFascin-betaGal) are capable of inhibiting betaGal-specific IgE production after adoptive transfer into naïve recipients. Moreover, suppression of IgE production was dependent on interferon (IFN)-gamma. To analyse the modalities of activation of CD4(+) and CD8(+) T cells regarding the localization of antigen synthesis following gene gun-mediated DNA immunization, we used the fascin promoter and the keratin 5 promoter (pK5-betaGal) to direct betaGal production mainly to dendritic cells (DCs) and to keratinocytes, respectively. Gene gun-mediated DNA immunization with each vector induced considerable activation of betaGal-specific CD8(+) cytotoxic T cells. Cytokine production by re-stimulated CD4(+) T cells in draining lymph nodes and immunoglobulin isotype profiles in sera of immunized mice indicated that immunization with pFascin-betaGal induced a T helper type 1 (Th1)-biased immune response, whereas immunization with pK5-betaGal generated a mixed Th1/Th2 immune response. Nevertheless, DNA vaccination with pFascin-betaGal and pK5-betaGal, respectively, efficiently inhibited specific IgE production in the mouse model of type I allergy. In conclusion, our data show that uptake of exogenous antigen produced by keratinocytes and its presentation by untransfected DCs as well as the presentation of antigen synthesized endogenously in DCs represent equivalent pathways for efficient priming of cellular immune responses.

  3. B Cells use Conserved Polarity Cues to Regulate Their Antigen Processing and Presentation Functions

    PubMed Central

    Yuseff, Maria-Isabel; Lennon-Duménil, Ana Maria

    2015-01-01

    The ability of B cells to produce high-affinity antibodies and to establish immunological memory in response to a wide range of pathogenic antigens is an essential part of the adaptive immune response. The initial step that triggers a humoral immune response involves the acquisition of antigens by B cells via their surface immunoglobulin, the B cell receptor (BCR). BCR-engaged antigens are transported into specialized lysosomal compartments where proteolysis and production of MHC class II-peptide complexes occur, a process referred to as antigen processing. Expression of MHC class II complexes at the B cell surface allows them to interact with T cells and to receive their help to become fully activated. In this review, we describe how B cells rely on conserved cell polarity mechanisms to coordinate local proteolytic secretion and mechanical forces at the B cell synapse enabling them to efficiently acquire and present extracellular antigens. We foresee that the mechanisms that dictate B cell activation can be used to tune B cell responses in the context of autoimmune diseases and cancer. PMID:26074919

  4. Unique Transcompartmental Bridge: Antigen-Presenting Cells Sampling across Endothelial and Mucosal Barriers

    PubMed Central

    Allen, Frederick; Tong, Alexander A.; Huang, Alex Y.

    2016-01-01

    Potentially harmful pathogens can gain access to tissues and organ systems through body sites that are in direct contact with the outside environment, such as the skin, the gut, and the airway mucosa. Antigen-presenting cells (APCs) represent a bridge between the innate and adaptive immunity, and their capacity for constant immune surveillance and rapid sampling of incoming pathogens and other potentially harmful antigens is central for mounting an effective and robust protective host response. The classical view is that APCs perform this task efficiently within the tissue to sense invading agents intra-compartmentally. However, recent data based on high resolution imaging support an additional transcompartmental surveillance behavior by APC by reaching across intact physical barriers. In this review, we summarize intravital microscopic evidences of APC to sample antigens transcompartmentally at the gut mucosa and other body sites. PMID:27375624

  5. Asymmetric Cell Division of T Cells Upon Antigen Presentation Utilizes Multiple Conserved Mechanisms

    PubMed Central

    Oliaro, Jane; Van Ham, Vanessa; Sacirbegovic, Faruk; Pasam, Anupama; Bomzon, Ze’ev; Pham, Kim; Ludford-Menting, Mandy J.; Waterhouse, Nigel J.; Bots, Michael; Hawkins, Edwin D.; Watt, Sally V.; Cluse, Leonie A.; Clarke, Chris J.P.; Izon, David J.; Chang, John T.; Thompson, Natalie; Gu, Min; Johnstone, Ricky W.; Smyth, Mark J.; Humbert, Patrick O.; Reiner, Steven L.; Russell, Sarah M.

    2013-01-01

    Asymmetric cell division is a potential means by which cell fate choices during an immune response are orchestrated. Defining the molecular mechanisms that underlie asymmetric division of T cells is paramount for determining the role of this process in the generation of effector and memory T cell subsets. In other cell types, asymmetric cell division is regulated by conserved polarity protein complexes that control the localization of cell fate determinants and spindle orientation during division. We have developed a tractable, in vitro model of naïve CD8+ T cells undergoing initial division while attached to dendritic cells during antigen presentation to investigate whether similar mechanisms might regulate asymmetric division of T cells. Using this system, we show that direct interactions with antigen presenting cells provide the cue for polarization of T cells. Interestingly, the immunological synapse disseminates before division even though the T cells retain contact with the antigen presenting cell. The cue from the antigen presenting cell is translated into polarization of cell fate determinants via the polarity network of the Par3 and Scribble complexes and orientation of the mitotic spindle during division is orchestrated by the Pins/G protein complex. These findings suggest that T cells have selectively adapted a number of evolutionarily conserved mechanisms to generate diversity through asymmetric cell division. PMID:20530266

  6. A large, benign prostatic cyst presented with an extremely high serum prostate-specific antigen level.

    PubMed

    Chen, Han-Kuang; Pemberton, Richard

    2016-01-08

    We report a case of a patient who presented with an extremely high serum prostate specific antigen (PSA) level and underwent radical prostatectomy for presumed prostate cancer. Surprisingly, the whole mount prostatectomy specimen showed only small volume, organ-confined prostate adenocarcinoma and a large, benign intraprostatic cyst, which was thought to be responsible for the PSA elevation. 2016 BMJ Publishing Group Ltd.

  7. Suppression of autophagy and antigen presentation by Mycobacterium tuberculosis PE_PGRS47.

    PubMed

    Saini, Neeraj K; Baena, Andres; Ng, Tony W; Venkataswamy, Manjunatha M; Kennedy, Steven C; Kunnath-Velayudhan, Shajo; Carreño, Leandro J; Xu, Jiayong; Chan, John; Larsen, Michelle H; Jacobs, William R; Porcelli, Steven A

    2016-08-15

    Suppression of major histocompatibility complex (MHC) class II antigen presentation is believed to be among the major mechanisms used by Mycobacterium tuberculosis to escape protective host immune responses. Through a genome-wide screen for the genetic loci of M. tuberculosis that inhibit MHC class II-restricted antigen presentation by mycobacteria-infected dendritic cells, we identified the PE_PGRS47 protein as one of the responsible factors. Targeted disruption of the PE_PGRS47 (Rv2741) gene led to attenuated growth of M. tuberculosis in vitro and in vivo, and a PE_PGRS47 mutant showed enhanced MHC class II-restricted antigen presentation during in vivo infection of mice. Analysis of the effects of deletion or over-expression of PE_PGRS47 implicated this protein in the inhibition of autophagy in infected host phagocytes. Our findings identify PE_PGRS47 as a functionally relevant, non-redundant bacterial factor in the modulation of innate and adaptive immunity by M. tuberculosis, suggesting strategies for improving antigen presentation and the generation of protective immunity during vaccination or infection.

  8. New Design of MHC Class II Tetramers to Accommodate Fundamental Principles of Antigen Presentation

    PubMed Central

    Landais, Elise; Romagnoli, Pablo A.; Corper, Adam L.; Shires, John; Altman, John D.; Wilson, Ian A.; Garcia, K. Christopher; Teyton, Luc

    2009-01-01

    Direct identification and isolation of antigen-specific T cells became possible with the development of “MHC tetramers”, based on fluorescent avidins displaying biotinylated peptide-MHC (pMHC) complexes. This approach, extensively used for MHC class I–restricted T cells, has met very limited success with MHC class II tetramers (pMHCT-2) for the detection of CD4+ specific T cells. In addition, a very large number of these reagents while capable of specifically activating T cells after being coated on solid support, are still unable to stain. In order to try to understand this puzzle and design usable tetramers, we examined each parameter critical for the production of pMHCT-2 using the I-Ad-OVA system as a model. Through this process the geometry of pMHC display by avidin tetramers was examined, as well as the stability of recombinant MHC molecules. However, we discovered that the most important factor limiting the reactivity of pMHCT-2 was the display of peptides. Indeed, long peptides, as presented by MHC class II molecules, can be bound to I-A/HLA-DQ molecules in more than one register as suggested by structural studies. This mode of anchorless peptide binding allows the selection of a broader repertoire on single peptides and should favor anti-infectious immune responses. Thus, beyond the technical improvements that we propose, the redesign of pMHCT-2 will give us the tools to evaluate the real size of the CD4 repertoire and help us in the production and testing of new vaccines. PMID:19923463

  9. Presenting Influenza A M2e Antigen on Recombinant Spores of Bacillus subtilis

    PubMed Central

    Obuchowski, Michał; Nidzworski, Dawid

    2016-01-01

    Effective vaccination against influenza virus infection is a serious problem mainly due to antigenic variability of the virus. Among many of investigated antigens, the extracellular domain of the M2 protein (M2e) features high homology in all strains of influenza A viruses and antibodies against M2e and is protective in animal models; this makes it a potential candidate for generation of a universal influenza vaccine. However, due to the low immunogenicity of the M2e, formulation of a vaccine based on this antigen requires some modification to induce effective immune responses. In this work we evaluated the possible use of Bacillus subtilis spores as a carrier of the Influenza A M2e antigen in mucosal vaccination. A tandem repeat of 4 consensus sequences coding for human—avian—swine—human M2e (M2eH-A-S-H) peptide was fused to spore coat proteins and stably exposed on the spore surface, as demonstrated by the immunostaining of intact, recombinant spores. Oral immunization of mice with recombinant endospores carrying M2eH-A-S-H elicited specific antibody production without the addition of adjuvants. Bacillus subtilis endospores can serve as influenza antigen carriers. Recombinant spores constructed in this work showed low immunogenicity although were able to induce antibody production. The System of influenza antigen administration presented in this work is attractive mainly due to the omitting time-consuming and cost-intensive immunogen production and purification. Therefore modification should be made to increase the immunogenicity of the presented system. PMID:27902762

  10. Regulation of NK-cell function by mucins via antigen-presenting cells.

    PubMed

    Laskarin, G; Redzovic, A; Medancic, S Srsen; Rukavina, D

    2010-12-01

    Decidual antigen-presenting cells including dendritic cells (DCs) and CD14(+) macrophages, as mediators of the first encounter with fetal antigens, appear to be critically involved in the initiation of primary immune response by regulating innate- and adaptive immunity. Interleukin-15, produced by them, permits the proliferation and differentiation of CD3(-)CD16(-)CD94(+)NKG2A(+)CD56(+bright) decidual NK cells that identify trophoblast cells. These cells are able to kill them after Th1 cytokine overstimulation and by increasing the release of preformed cytotoxic mediators. Thus, the local microenvironment is a potent modulator of antigen-presenting cell functions. Tumor associated glycoprotein-72 (TAG-72) and mucine 1 (MUC-1) are glycoproteins secreted by uterine epithelial cells. Our hypothesis is that TAG-72 and MUC-1 are the natural ligands for carbohydrate recognition domains (CRDs) of endocytic mannose receptor (MR or CD206) and DC-specific ICAM non-integrin (DC-SIGN or CD209) expressed on decidual CD14(+) macrophages and CD1a(+) DCs. They might be able to condition antigen-presenting cells to produce distinct profiles of cyto/chemokines with consequential reduction in NK-cell numbers and cytotoxic potential leading to insufficient control over trophoblast growth. This hypothesis could explain the disappearance of MUC-1 beneath the attached embryo during the process of successful implantation when tight regulation of trophoblast invasion is needed. As IL-15 is the earliest and the most important factor in NK-cell proliferation, differentiation, and maturation, we expected primarily an increase of IL-15 expression in antigen-presenting cells concomitant with the disappearance of mucins and the enhancement in NK cells numbers and of cytotoxic potential after their close contact with early pregnancy decidual antigen-presenting cells. If our hypothesis is correct, it would contribute to the understanding of the role of mucins in the redirection of immune response

  11. CLIC1 regulates dendritic cell antigen processing and presentation by modulating phagosome acidification and proteolysis

    PubMed Central

    Salao, Kanin; Jiang, Lele; Li, Hui; Tsai, Vicky W.-W.; Husaini, Yasmin; Curmi, Paul M. G.; Brown, Louise J.; Brown, David A.

    2016-01-01

    ABSTRACT Intracellular chloride channel protein 1 (CLIC1) participates in inflammatory processes by regulating macrophage phagosomal functions such as pH and proteolysis. Here, we sought to determine if CLIC1 can regulate adaptive immunity by actions on dendritic cells (DCs), the key professional antigen presenting cells. To do this, we first generated bone marrow-derived DCs (BMDCs) from germline CLIC1 gene-deleted (CLIC1−/−) and wild-type (CLIC1+/+) mice, then studied them in vitro and in vivo. We found phagocytosis triggered cytoplasmic CLIC1 translocation to the phagosomal membrane where it regulated phagosomal pH and proteolysis. Phagosomes from CLIC1−/− BMDCs displayed impaired acidification and proteolysis, which could be reproduced if CLIC1+/+, but not CLIC1−/− cells, were treated with IAA94, a CLIC family ion channel blocker. CLIC1−/− BMDC displayed reduced in vitro antigen processing and presentation of full-length myelin oligodendrocyte glycoprotein (MOG) and reduced MOG-induced experimental autoimmune encephalomyelitis. These data suggest that CLIC1 regulates DC phagosomal pH to ensure optimal processing of antigen for presentation to antigen-specific T-cells. Further, they indicate that CLIC1 is a novel therapeutic target to help reduce the adaptive immune response in autoimmune diseases. PMID:27113959

  12. Connecting the Dots: Artificial Antigen Presenting Cell-Mediated Modulation of Natural Killer T Cells

    PubMed Central

    Sun, Wenji; Subrahmanyam, Priyanka B.; East, James E.

    2012-01-01

    Natural killer T (NKT) cells constitute an important subset of T cells that can both directly and indirectly mediate antitumor immunity. However, we and others have reported that cancer patients have a reduction in both NKT cell number and function. NKT cells can be stimulated and expanded with α-GalCer and cytokines and these expanded NKT cells retain their phenotype, remain responsive to antigenic stimulation, and display cytotoxic function against tumor cell lines. These data strongly favor the use of ex vivo expanded NKT cells in adoptive immunotherapy. NKT cell based-immunotherapy has been limited by the use of autologous antigen-presenting cells, which can vary substantially in their quantity and quality. A standardized system that relies on artificial antigen-presenting cells (aAPCs) could produce the stimulating effects of dendritic cell (DC) without the pitfalls of allo- or xenogeneic cells. In this review, we discuss the progress that has been made using CD1d-based aAPC and how this acellular antigen presenting system can be used in the future to enhance our understanding of NKT cell biology and to develop NKT cell-specific adoptive immunotherapeutic strategies. PMID:23050947

  13. Relation between Seroreactivity to Low-Molecular-Weight Helicobacter pylori-Specific Antigens and Disease Presentation

    PubMed Central

    Vilaichone, Ratha-Korn; Mahachai, Varocha; Kositchaiwat, Chomsri; Graham, David Y.; Yamaoka, Yoshio

    2003-01-01

    The identification of Helicobacter pylori-strain specific factors that correlate with clinical outcome has remained elusive. We investigated possible relationships between a group of H. pylori antigens and clinical outcome and compared an immunoblot assay kit (HelicoBlot, version 2.1 [HB 2.1]; Genelabs Diagnostics) with an established serological test, the high-molecular-weight cell-associated protein test (HM-CAP). We used sera from 156 Thai patients with different disease presentations, including 43 patients with gastric cancer, 64 patients with gastric ulcer, and 49 patients with nonulcer dyspepsia (NUD). HB 2.1 was compared to HM-CAP as a diagnostic test for H. pylori infection. The seroprevalence of H. pylori was significantly higher among gastric cancer patients than among patients with NUD (93 and 67%, respectively; P < 0.01). Among the H. pylori-seropositive patients, the presence of the antibody to the 37,000-molecular-weight antigen (37K antigen) was inversely related to the presence of gastric cancer (e.g., for gastric cancer patients compared with NUD patients, odds ratio [OR] = 0.28 and 95% confidence interval [CI] = 0.1 to 0.8). The presence of antibody to the 35K antigen was higher in gastric ulcer patients than in NUD patients (OR = 11.5; 95% CI = 2.4 to 54.3). The disease associations of antibodies to the 35K and 37K antigens are consistent with the possibility that these antigens are either indirect markers for H. pylori-related diseases or have specific active or protective roles in H. pylori-related diseases. PMID:14607862

  14. B-Cell Cross-Presentation of Autologous Antigen Precipitates Diabetes

    PubMed Central

    Mariño, Eliana; Tan, Bernice; Binge, Lauren; Mackay, Charles R.; Grey, Shane T.

    2012-01-01

    For autoimmune conditions like type 1 diabetes to progress, self-reactive CD8+ T cells would need to interact with peptide–antigen cross-presented on the surface of antigen-presenting cells in a major histocompatibility complex (MHC) class I-restricted fashion. However, the mechanisms by which autoantigen is cross-presented remain to be identified. In this study, we show cross-presentation of islet-derived autoantigens by B cells. B cells engage self-reactive CD8+ T cells in the pancreatic lymph node, driving their proliferative expansion and differentiation into granzyme B+interferon-γ+lysosomal-associated membrane protein 1+ effector cells. B-cell cross-presentation of insulin required proteolytic cleavage and endosomal localization and was sensitive to inhibitors of protein trafficking. Absent B-cell MHC class I, or B-cell receptor restriction to an irrelevant specificity, blunted the expansion of self-reactive CD8+ T cells, suggesting B-cell antigen capture and presentation are critical in vivo events for CD8 activation. Indeed, the singular loss of B-cell MHC class I subverted the conversion to clinical diabetes in NOD mice, despite the presence of a pool of activated, and B cell–dependent, interleukin-21–expressing Vβ4+CD4+ T cells. Thus, B cells govern the transition from clinically silent insulitis to frank diabetes by cross-presenting autoantigen to self-reactive CD8+ T cells. PMID:22829452

  15. Assessing Preservice Teachers' Presentation Capabilities: Contrasting the Modes of Communication with the Constructed Impression

    ERIC Educational Resources Information Center

    Bower, Matt G.; Moloney, Robyn A.; Cavanagh, Michael S.; Sweller, Naomi

    2013-01-01

    A research-based understanding of how to develop and assess classroom presentation skills is vital for the effective development of pre-service teacher communication capabilities. This paper identifies and compares two different models of assessing pre-service teachers' presentation performance--one based on the Modes of Communication (voice,…

  16. Rational design of nanoparticles towards targeting antigen-presenting cells and improved T cell priming.

    PubMed

    Zupančič, Eva; Curato, Caterina; Paisana, Maria; Rodrigues, Catarina; Porat, Ziv; Viana, Ana S; Afonso, Carlos A M; Pinto, João; Gaspar, Rogério; Moreira, João N; Satchi-Fainaro, Ronit; Jung, Steffen; Florindo, Helena F

    2017-07-28

    Vaccination is a promising strategy to trigger and boost immune responses against cancer or infectious disease. We have designed, synthesized and characterized aliphatic-polyester (poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NP) to investigate how the nature of protein association (adsorbed versus entrapped) and polymer/surfactant concentrations impact on the generation and modulation of antigen-specific immune responses. The ability of the NP formulations to target dendritic cells (DC), be internalized and activate the T cells was characterized and optimized in vitro and in vivo using markers of DC activation and co-stimulatory molecules. Ovalbumin (OVA) was used as a model antigen in combination with the engraftment of CD4(+) and CD8(+) T cells, carrying a transgenic OVA-responding T cell receptor (TCR), to trace and characterize the activation of antigen-specific CD4(+) and CD8(+) lymph node T cells upon NP vaccination. Accordingly, the phenotype and frequency of immune cell stimulation induced by the NP loaded with OVA, isolated or in combination with synthetic unmethylated cytosine-phosphate-guanine (CpG) oligodeoxynucleotide (ODN) motifs, were characterized. DC-NP interactions increased with incubation time, presenting internalization values between 50 and 60% and 30-40%, in vitro and in vivo, respectively. Interestingly, animal immunization with antigen-adsorbed NP up-regulated major histocompatibility complex (MHC) class II (MHCII), while NP entrapping the antigen up-regulated MHCI, suggesting a more efficient cross-presentation. On the other hand, rather surprisingly, the surfactant used in the NP formulation had a major impact on the activation of antigen presenting cells (APC). In fact, DC collected from lymph nodes of animals immunized with NP prepared using poly(vinil alcohol) (PVA), as a surfactant, expressed significantly higher levels of CD86, MHCI and MHCII. In addition, those NP prepared with PVA and co-entrapping OVA and the toll

  17. Effect of antigen/antibody ratio on macrophage uptake, processing, and presentation to T cells of antigen complexed with polyclonal antibodies

    PubMed Central

    1991-01-01

    Activation of a galactosidase-specific murine T hybridoma clone and of a human tetanus toxoid-specific T clone by antigen-presenting cells (APC) was used to evaluate the regulatory function of antibodies complexed with the relevant antigen. Complexed antigen, in fact, is taken up with high efficiency thanks to Fc receptors borne by APC. Antibody/antigen ratio in the complexes proved to be a critical parameter in enhancing antigen presentation. Complexes in moderate antibody excess provided optimal T cell activation independently of the physical state of the complexes (precipitated by a second antibody or solubilized by complement). Complexes in extreme antibody excess, on the contrary, did not yield T cell activation although taken up by APC efficiently. The effect of antibodies at extreme excess was observed with substimulatory dose of antigen (loss of potentiation) and with optimal dose of antigen (loss of stimulation). An excess of specific polyclonal antibodies hampers proteolytic degradation of antigen in vitro, supporting the view that a similar mechanism may operate within the APC that have internalized immune complexes in extreme antibody excess. The possibility that immune complex forming in extreme antibody excess may turn off the T cell response is proposed as a regulatory mechanism. PMID:1985125

  18. Salt bridge residues between I-Ak dimer of dimers alpha-chains modulate antigen presentation.

    PubMed

    Yadati, S; Nydam, T; Demian, D; Wade, T K; Gabriel, J L; Barisas, B G; Wade, W F

    1999-03-15

    Class II dimers of dimers are predicted to have functional significance in antigen presentation. The putative contact amino acids of the I-Ak class II dimer of dimers have been identified by molecular modeling based on the DR1 crystal structure (Nydam et al., Int. Immunol. 10, 1237,1998). We have previously reported the role in antigen presentation of dimer of dimers contact amino acids located in the C-terminal domains of the alpha- and beta-chains of class II. Our calculations show that residues Ealpha89 and Ralpha145 in the alpha2-domain form an inter alpha-chain salt bridge between pairs of alphabeta-heterodimers. Other residues, Qalpha92 and Nalpha115, may be involved in close association in that part of the alpha-chain. We investigated the role of these amino acids on class II expression and antigen presentation. Class II composed of an Ealpha89K substituted alpha-chain paired with a wt beta-chain exhibited inhibited antigen presentation and expression of alpha-chain serologic epitopes. In contrast, mutation of Ralpha145E had less affect on antigen presentation and did not affect I-Ak serologic epitopes. Interchanging charges of the salt bridge residues by expressing both Ralpha145E and Ealpha89K on the same chain obviated the large negative effect of the Ealpha89K mutation on antigen presentation but not on the serologic epitopes. Our results are similar for those reported for mutation of DR3's inter-chain salt bridge with the exception that double mutants did not moderate the DR3 defect. Interestingly, the amino acids differences between I-A and DR change the location of the inter-chain salt bridges. In DR1 these residues are located at positions Ealpha88 and Kalpha111; in I-Ak these residues are located at position Ealpha89 and Ralpha145. Inter alpha-chain salt bridges are thus maintained in various class II molecules by amino acids located in different parts of the alpha2-domain. This conservation of structure suggests that considerable functional

  19. Unidirectional transfer of microRNA-loaded exosomes from T cells to antigen-presenting cells

    PubMed Central

    Mittelbrunn, María; Gutiérrez-Vázquez, Cristina; Villarroya-Beltri, Carolina; González, Susana; Sánchez-Cabo, Fátima; González, Manuel Ángel; Bernad, Antonio; Sánchez-Madrid, Francisco

    2011-01-01

    The immune synapse is an exquisitely evolved means of communication between T cells and antigen-presenting cells (APCs) during antigen recognition. Recent evidence points to the transfer of RNA via exosomes as a novel mode of intercellular communication. Here we show that exosomes of T, B and dendritic immune cells contain microRNA (miRNA) repertoires that differ from those of their parent cells. We investigate whether miRNAs are exchanged during cognate immune interactions, and demonstrate the existence of antigen-driven unidirectional transfer of miRNAs from the T cell to the APC, mediated by the delivery of CD63+ exosomes on immune synapse formation. Inhibition of exosome production by targeting neutral sphingomyelinase-2 impairs transfer of miRNAs to APCs. Moreover, miRNAs transferred during immune synapsis are able to modulate gene expression in recipient cells. Thus, our results support a mechanism of cellular communication involving antigen-dependent, unidirectional intercellular transfer of miRNAs by exosomes during immune synapsis. PMID:21505438

  20. Improved Transgenic Mouse Model for Studying HLA Class I Antigen Presentation

    PubMed Central

    Huang, Man; Zhang, Wei; Guo, Jie; Wei, Xundong; Phiwpan, Krung; Zhang, Jianhua; Zhou, Xuyu

    2016-01-01

    HLA class I (HLA-I) transgenic mice have proven to be useful models for studying human MHC-related immune responses over the last two decades. However, differences in the processing and presentation machinery between humans and mice may have profound effects on HLA-I restricted antigen presentation. In this study, we generated a novel human TAP-LMP (hTAP-LMP) gene cluster transgenic mouse model carrying an intact human TAP complex and two human immunoproteasome LMP subunits, PSMB8/PSMB9. By crossing the hTAP-LMP strain with different HLA-I transgenic mice, we found that the expression levels of human HLA-I molecules, especially the A3 supertype members (e.g., A11 and A33), were remarkably enhanced in corresponding HLA-I/hTAP-LMP transgenic mice. Moreover, we found that humanized processing and presentation machinery increased antigen presentation of HLA-A11-restricted epitopes and promoted the rapid reduction of hepatitis B virus (HBV) infection in HLA-A11/hTAP-LMP mice. Together, our study highlights that HLA-I/hTAP-LMP mice are an improved model for studying antigen presentation of HLA-I molecules and their related CTL responses. PMID:27634283

  1. Fusion of antigen to a dendritic cell targeting chemokine combined with adjuvant yields a malaria DNA vaccine with enhanced protective capabilities.

    PubMed

    Luo, Kun; Zhang, Hong; Zavala, Fidel; Biragyn, Arya; Espinosa, Diego A; Markham, Richard B

    2014-01-01

    Although sterilizing immunity to malaria can be elicited by irradiated sporozoite vaccination, no clinically practical subunit vaccine has been shown to be capable of preventing the approximately 600,000 annual deaths attributed to this infection. DNA vaccines offer several potential advantages for a disease that primarily affects the developing world, but new approaches are needed to improve the immunogenicity of these vaccines. By using a novel, lipid-based adjuvant, Vaxfectin, to attract immune cells to the immunization site, in combination with an antigen-chemokine DNA construct designed to target antigen to immature dendritic cells, we elicited a humoral immune response that provided sterilizing immunity to malaria challenge in a mouse model system. The chemokine, MIP3αCCL20, did not significantly enhance the cellular infiltrate or levels of cytokine or chemokine expression at the immunization site but acted with Vaxfectin to reduce liver stage malaria infection by orders of magnitude compared to vaccine constructs lacking the chemokine component. The levels of protection achieved were equivalent to those observed with irradiated sporozoites, a candidate vaccine undergoing development for further large scale clinical trial. Only vaccination with the combined regimen of adjuvant and chemokine provided 80-100% protection against the development of bloodstream infection. Treating the immunization process as requiring the independent steps of 1) attracting antigen-presenting cells to the site of immunization and 2) specifically directing vaccine antigen to the immature dendritic cells that initiate the adaptive immune response may provide a rational strategy for the development of a clinically applicable malaria DNA vaccine.

  2. Fusion of Antigen to a Dendritic Cell Targeting Chemokine Combined with Adjuvant Yields a Malaria DNA Vaccine with Enhanced Protective Capabilities

    PubMed Central

    Luo, Kun; Zhang, Hong; Zavala, Fidel; Biragyn, Arya; Espinosa, Diego A.; Markham, Richard B.

    2014-01-01

    Although sterilizing immunity to malaria can be elicited by irradiated sporozoite vaccination, no clinically practical subunit vaccine has been shown to be capable of preventing the approximately 600,000 annual deaths attributed to this infection. DNA vaccines offer several potential advantages for a disease that primarily affects the developing world, but new approaches are needed to improve the immunogenicity of these vaccines. By using a novel, lipid-based adjuvant, Vaxfectin, to attract immune cells to the immunization site, in combination with an antigen-chemokine DNA construct designed to target antigen to immature dendritic cells, we elicited a humoral immune response that provided sterilizing immunity to malaria challenge in a mouse model system. The chemokine, MIP3αCCL20, did not significantly enhance the cellular infiltrate or levels of cytokine or chemokine expression at the immunization site but acted with Vaxfectin to reduce liver stage malaria infection by orders of magnitude compared to vaccine constructs lacking the chemokine component. The levels of protection achieved were equivalent to those observed with irradiated sporozoites, a candidate vaccine undergoing development for further large scale clinical trial. Only vaccination with the combined regimen of adjuvant and chemokine provided 80–100% protection against the development of bloodstream infection. Treating the immunization process as requiring the independent steps of 1) attracting antigen-presenting cells to the site of immunization and 2) specifically directing vaccine antigen to the immature dendritic cells that initiate the adaptive immune response may provide a rational strategy for the development of a clinically applicable malaria DNA vaccine. PMID:24599116

  3. Inhibiting DNA methylation activates cancer testis antigens and expression of the antigen processing and presentation machinery in colon and ovarian cancer cells.

    PubMed

    Siebenkäs, Cornelia; Chiappinelli, Katherine B; Guzzetta, Angela A; Sharma, Anup; Jeschke, Jana; Vatapalli, Rajita; Baylin, Stephen B; Ahuja, Nita

    2017-01-01

    Innovative therapies for solid tumors are urgently needed. Recently, therapies that harness the host immune system to fight cancer cells have successfully treated a subset of patients with solid tumors. These responses have been strong and durable but observed in subsets of patients. Work from our group and others has shown that epigenetic therapy, specifically inhibiting the silencing DNA methylation mark, activates immune signaling in tumor cells and can sensitize to immune therapy in murine models. Here we show that colon and ovarian cancer cell lines exhibit lower expression of transcripts involved in antigen processing and presentation to immune cells compared to normal tissues. In addition, treatment with clinically relevant low doses of DNMT inhibitors (that remove DNA methylation) increases expression of both antigen processing and presentation and Cancer Testis Antigens in these cell lines. We confirm that treatment with DNMT inhibitors upregulates expression of the antigen processing and presentation molecules B2M, CALR, CD58, PSMB8, PSMB9 at the RNA and protein level in a wider range of colon and ovarian cancer cell lines and treatment time points than had been described previously. In addition, we show that DNMTi treatment upregulates many Cancer Testis Antigens common to both colon and ovarian cancer. This increase of both antigens and antigen presentation by epigenetic therapy may be one mechanism to sensitize patients to immune therapies.

  4. Stereotactic Radiation Therapy Augments Antigen-Specific PD-1-Mediated Anti-Tumor Immune Responses via Cross-Presentation of Tumor Antigen

    PubMed Central

    Sharabi, Andrew B.; Nirschl, Christopher J.; Kochel, Christina M.; Nirschl, Thomas R.; Francisca, Brian J.; Velarde, Esteban; Deweese, Theodore L.; Drake, Charles G.

    2014-01-01

    The immune-modulating effects of radiation therapy have gained considerable interest recently and there have been multiple reports of synergy between radiation and immunotherapy. However, additional pre-clinical studies are needed to demonstrate the antigen-specific nature of radiation-induced immune responses and elucidate potential mechanisms of synergy with immunotherapy. Here we demonstrate the ability of stereotactic radiotherapy to induce endogenous antigen-specific immune responses when combined with anti-PD-1 checkpoint blockade immunotherapy. Using the small animal radiation research platform (SARRP), image-guided stereotactic radiotherapy delivered to B16-OVA melanoma or 4T1-HA breast carcinoma tumors resulted in the development of antigen-specific T and B cell-mediated immune responses. These immune-stimulating effects of radiotherapy were significantly increased when combined with either anti-PD-1 therapy or regulatory T cell (Treg) depletion, resulting in improved local tumor control. Phenotypic analyses of antigen-specific CD8 T cells revealed that radiotherapy increased the percentage of antigen-experienced T cells and effector memory T cells. Mechanistically we found that radiotherapy up-regulates tumor-associated antigen-MHC complexes, enhances antigen cross-presentation in the draining lymph node, and increased T-cell infiltration into tumors. These findings demonstrate the ability of radiotherapy to prime an endogenous antigen-specific immune response and provide additional mechanistic rationale for combining radiation with PD-1 blockade in the clinic. PMID:25527358

  5. Studying MHC class II presentation of immobilized antigen by B lymphocytes.

    PubMed

    Yuseff, M I; Lennon-Dumenil, A M

    2013-01-01

    The ability of B lymphocytes to capture external antigens (Ag) and present them as peptide fragments, loaded on Major Histocompatibility complex (MHC) class II molecules, to CD4(+) T cells is a crucial part of the adaptive immune response. This allows T-B cooperation, a cellular communication that is required for B cells to develop into germinal centers (GC) and form mature high-affinity antibody producing cells and to further develop B cell memory. MHC class II antigen presentation by B lymphocytes is a multistep process involving (1) Recognition and capture of external Ag by B lymphocytes through their B cell receptor (BCR); (2) Ag processing, which comprises the degradation of Ag in internal compartments within the B cell and loading of the corresponding peptide fragments on MHC class II molecules and (3) Presentation of MHC II-peptide complexes to CD4(+) T cells. Here, we describe how to study MHC class II antigen presentation by B lymphocytes at these three major levels.

  6. Presenting native-like trimeric HIV-1 antigens with self-assembling nanoparticles

    PubMed Central

    He, Linling; de Val, Natalia; Morris, Charles D.; Vora, Nemil; Thinnes, Therese C.; Kong, Leopold; Azadnia, Parisa; Sok, Devin; Zhou, Bin; Burton, Dennis R.; Wilson, Ian A; Nemazee, David; Ward, Andrew B.; Zhu, Jiang

    2016-01-01

    Structures of BG505 SOSIP.664 trimer in complex with broadly neutralizing antibodies (bNAbs) have revealed the critical role of trimeric context for immune recognition of HIV-1. Presentation of trimeric HIV-1 antigens on nanoparticles may thus provide promising vaccine candidates. Here we report the rational design, structural analysis and antigenic evaluation of HIV-1 trimer-presenting nanoparticles. We first demonstrate that both V1V2 and gp120 can be presented in native-like trimeric conformations on nanoparticles. We then design nanoparticles presenting various forms of stabilized gp140 trimer based on ferritin and a large, 60-meric E2p that displays 20 spikes mimicking virus-like particles (VLPs). Particle assembly is confirmed by electron microscopy (EM), while antigenic profiles are generated using representative bNAbs and non-NAbs. Lastly, we demonstrate high-yield gp140 nanoparticle production and robust stimulation of B cells carrying cognate VRC01 receptors by gp120 and gp140 nanoparticles. Together, our study provides an arsenal of multivalent immunogens for HIV-1 vaccine development. PMID:27349934

  7. Delivery of a viral antigen to the class I processing and presentation pathway by Listeria monocytogenes

    PubMed Central

    1994-01-01

    Listeria monocytogenes is a facultative intracellular pathogen that grows in the cytoplasm of infected host cells. We examined the capacity of L. monocytogenes to introduce influenza nucleoprotein (NP) into the class I pathway of antigen presentation both in vitro and in vivo. Recombinant L. monocytogenes secreting a fusion of listeriolysin O and NP (LLO-NP) targeted infected cells for lysis by NP-specific class I- restricted cytotoxic T cells. Antigen presentation occurred in the context of three different class I haplotypes in vitro. A hemolysin- negative L. monocytogenes strain expressing LLO-NP was able to present in a class II-restricted manner. However, it failed to target infected cells for lysis by CD8+ T cells, indicating that hemolysin-dependent bacterial escape from the vacuole is necessary for class I presentation in vitro. Immunization of mice with a recombinant L. monocytogenes strain that stably expressed and secreted LLO-NP induced NP-specific CD8+ cytotoxic T lymphocytes. These studies have implications for the use of L. monocytogenes to deliver potentially any antigen to the class I pathway in vivo. PMID:7964496

  8. Autologous Dendritic Cells Prolong Allograft Survival Through Tmem176b-Dependent Antigen Cross-Presentation

    PubMed Central

    Charnet, P.; Savina, A.; Tilly, G.; Gautreau, L.; Carretero-Iglesia, L.; Beriou, G.; Cebrian, I.; Cens, T.; Hepburn, L.; Chiffoleau, E.; Floto, R. A.; Anegon, I.; Amigorena, S.; Hill, M.; Cuturi, M. C.

    2015-01-01

    The administration of autologous (recipient-derived) tolerogenic dendritic cells (ATDCs) is under clinical evaluation. However, the molecular mechanisms by which these cells prolong graft survival in a donor-specific manner is unknown. Here, we tested mouse ATDCs for their therapeutic potential in a skin transplantation model. ATDC injection in combination with anti-CD3 treatment induced the accumulation of CD8+CD11c+ T cells and significantly prolonged allograft survival. TMEM176B is an intracellular protein expressed in ATDCs and initially identified in allograft tolerance. We show that Tmem176b−/− ATDCs completely failed to trigger both phenomena but recovered their effect when loaded with donor peptides before injection. These results strongly suggested that ATDCs require TMEM176B to cross-present antigens in a tolerogenic fashion. In agreement with this, Tmem176b−/− ATDCs specifically failed to cross-present male antigens or ovalbumin to CD8+ T cells. Finally, we observed that a Tmem176b-dependent cation current controls phagosomal pH, a critical parameter in cross-presentation. Thus, ATDCs require TMEM176B to cross-present donor antigens to induce donor-specific CD8+CD11c+ T cells with regulatory properties and prolong graft survival. PMID:24731243

  9. Antigen-presenting cells in human cutaneous leishmaniasis due to Leishmania major.

    PubMed Central

    ElHassan, A M; Gaafar, A; Theander, T G

    1995-01-01

    In this study biopsies from skin lesions and draining lymph nodes of patients suffering from cutaneous leishmaniasis caused by Leishmania major were examined by immunohistochemistry, and by light and electron microscopy to identify the types of antigen-presenting cells (APC) and their location. APC, identified morphologically and by their expression of specific cell markers, included Langerhans cells, macrophages, follicular dendritic cells, and interdigitating reticulum cells of the paracortex of lymph nodes. These cells expressed MHC class II antigens and contained Leishmania antigen. Since some keratinocytes and endothelial cells also showed these characteristics, they may also act as APC. By examining tissue samples from skin lesions and draining lymph nodes it was possible to follow the probable route of trafficking of various inflammatory cells between the skin lesion and lymph nodes. Leishmania antigen containing Langerhans cells were found in the epidermis, dermis and the regional lymph nodes. We believe these cells translocate from the epidermis to the dermis, where they take up antigen and migrate to the paracortex of the regional lymph nodes. There they are intimately associated with cells of the paracortex, and could be involved in the generation of Leishmania-specific T memory cells. LFA-1-positive T cells of the CD45RO phenotype were found in the skin lesion. Venular endothelium in the skin lesions expressed intercellular adhesion molecule-1 (ICAM-1), which is the ligand for LFA-1. The migration of lymphocytes from the vascular lumen to the site of inflammation is possibly a result of the interaction of these two adhesion molecules. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:7882568

  10. Processing and presentation of an antigen of Mycobacterium avium require access to an acidified compartment with active proteases.

    PubMed Central

    Holsti, M A; Allen, P M

    1996-01-01

    We have generated a murine T-cell hybridoma, 1C9, which recognizes an antigen expressed by a virulent clinical isolate of Mycobacterium avium. Both peritoneal exudate macrophages and bone marrow-derived macrophages infected in vitro with M. avium process and present the antigen to the T-cell hybridoma. Gel filtration chromatography of a sonicate of M. avium followed by T-cell Western blotting (immunoblotting) demonstrated that the antigen recognized by hybridoma 1C9 is approximately 50 kDa. In addition, treatment of macrophages with the lysosomotropic agent chloroquine or with inhibitors of acid proteases inhibits processing and presentation of the antigen. These results indicate that the antigen must encounter an acidic compartment with active proteases for processing and presentation to occur. Our results are discussed in the context of our current understanding of how mycobacterial antigens are processed and presented by infected macrophages to T cells. PMID:8926074

  11. Antigen Presentation, Autoantigens, and Immune Regulation in Multiple Sclerosis and Other Autoimmune Diseases

    PubMed Central

    Riedhammer, Christine; Weissert, Robert

    2015-01-01

    Antigen presentation is in the center of the immune system, both in host defense against pathogens, but also when the system is unbalanced and autoimmune diseases like multiple sclerosis (MS) develop. It is not just by chance that a major histocompatibility complex gene is the major genetic susceptibility locus in MS; a feature that MS shares with other autoimmune diseases. The exact etiology of the disease, however, has not been fully understood yet. T cells are regarded as the major players in the disease, but most probably a complex interplay of altered central and peripheral tolerance mechanisms, T-cell and B-cell functions, characteristics of putative autoantigens, and a possible interference of environmental factors like microorganisms are at work. In this review, new data on all these different aspects of antigen presentation and their role in MS will be discussed, probable autoantigens will be summarized, and comparisons to other autoimmune diseases will be drawn. PMID:26136751

  12. Modulation of Immune Responses by Exosomes Derived from Antigen-Presenting Cells

    PubMed Central

    Shenoda, Botros B.; Ajit, Seena K.

    2016-01-01

    Exosome-mediated signaling is important in mediating the inflammatory response. To exert their biological or pathophysiological functions in the recipient cells, exosomes deliver a diverse array of biomacromolecules including long and short coding and non-coding RNAs, proteins, and lipids. Exosomes secreted by antigen-presenting cells can confer therapeutic benefits by attenuating or stimulating the immune response. Exosomes play a crucial role in carrying and presenting functional major histocompatibility peptide complexes to modulate antigen-specific T cell responses. Exosomes from Dendritic Cells (DCs) can activate T and B cells and have been explored for their immunostimulatory properties in cancer therapy. The immunosuppressive properties of exosomes derived from macrophages and DCs can reduce inflammation in animal models for several inflammatory disorders. This review focuses on the protective role of exosomes in attenuating inflammation or augmenting immune response, emphasizing studies on exosomes derived from DCs and macrophages. PMID:27660518

  13. Ethanol Metabolism Alters Major Histocompatibility Complex Class I-Restricted Antigen Presentation In Liver Cells

    PubMed Central

    Osna, Natalia A.; White, Ronda L.; Thiele, Geoffrey M.; Donohue, Terrence M.

    2009-01-01

    The proteasome is a major enzyme that cleaves proteins for antigen presentation. Cleaved peptides traffic to the cell surface, where they are presented in the context of MHC class I. Recognition of these complexes by cytotoxic T lymphocytes is crucial for elimination of cells bearing “non-self” proteins. Our previous studies revealed that ethanol suppresses proteasome function in ethanol-metabolizing liver cells. We hypothesized that proteasome suppression reduces the hydrolysis of antigenic peptides, thereby decreasing the presentation of the peptide-MHC class I-complexes on the cell surface. To test this, we used the mouse hepatocyte cell line (CYP2E1/ADH-transfected HepB5 cells) or primary mouse hepatocytes, both derived from livers of C57Bl/6 mice, which present the ovalbumin peptide, SIINFEKL, complexed with H2Kb. To induce H2Kb expression, HepB5 cells were treated with interferon gamma (IFNγ) and then exposed to ethanol. In these cells, ethanol metabolism decreased not only proteasome activity, but also hydrolysis of the C-extended peptide, SIINFEKL-TE and the presentation of SIINFEKL-H2Kb complexes measured after the delivery of SIINFEKL-TE to cytoplasm. The suppressive effects of ethanol were, in part, attributed to ethanol-elicited impairment of IFNγ signaling. However, in primary hepatocytes, even in the absence of IFNγ, we observed a similar decline in proteasome activity and antigen presentation after ethanol exposure. We conclude that proteasome function is directly suppressed by ethanol metabolism and indirectly, by preventing the activating effects of IFNγ. Ethanol-elicited reduction in proteasome activity contributes to the suppression of SIINFEKL-H2Kb presentation on the surface of liver cells. Immune response to viral antigens plays a crucial role in the pathogenesis of hepatitis C or B viral infections (HCV and HBV, respectively). Professional antigen-presenting cells (dendritic cells and macrophages) are responsible for priming the

  14. Cationic liposomes promote antigen cross-presentation in dendritic cells by alkalizing the lysosomal pH and limiting the degradation of antigens.

    PubMed

    Gao, Jie; Ochyl, Lukasz J; Yang, Ellen; Moon, James J

    2017-01-01

    Cationic liposomes (CLs) have been widely examined as vaccine delivery nanoparticles since they can form complexes with biomacromolecules, promote delivery of antigens and adjuvant molecules to antigen-presenting cells (APCs), and mediate cellular uptake of vaccine components. CLs are also known to trigger antigen cross-presentation - the process by which APCs internalize extracellular protein antigens, degrade them into minimal CD8(+) T-cell epitopes, and present them in the context of major histocompatibility complex-I (MHC-I). However, the precise mechanisms behind CL-mediated induction of cross-presentation and cross-priming of CD8(+) T-cells remain to be elucidated. In this study, we have developed two distinct CL systems and examined their impact on the lysosomal pH in dendritic cells (DCs), antigen degradation, and presentation of peptide:MHC-I complexes to antigen-specific CD8(+) T-cells. To achieve this, we have used 3β-[N-(N',N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) as the prototypical components of CLs with tertiary amine groups and compared the effect of CLs and anionic liposomes on lysosomal pH, antigen degradation, and cross-presentation by DCs. Our results showed that CLs, but not anionic liposomes, elevated the lysosomal pH in DCs and reduced antigen degradation, thereby promoting cross-presentation and cross-priming of CD8(+) T-cell responses. These studies shed new light on CL-mediated cross-presentation and suggest that intracellular fate of vaccine components and subsequent immunological responses can be controlled by rational design of nanomaterials.

  15. Cationic liposomes promote antigen cross-presentation in dendritic cells by alkalizing the lysosomal pH and limiting the degradation of antigens

    PubMed Central

    Gao, Jie; Ochyl, Lukasz J; Yang, Ellen; Moon, James J

    2017-01-01

    Cationic liposomes (CLs) have been widely examined as vaccine delivery nanoparticles since they can form complexes with biomacromolecules, promote delivery of antigens and adjuvant molecules to antigen-presenting cells (APCs), and mediate cellular uptake of vaccine components. CLs are also known to trigger antigen cross-presentation – the process by which APCs internalize extracellular protein antigens, degrade them into minimal CD8+ T-cell epitopes, and present them in the context of major histocompatibility complex-I (MHC-I). However, the precise mechanisms behind CL-mediated induction of cross-presentation and cross-priming of CD8+ T-cells remain to be elucidated. In this study, we have developed two distinct CL systems and examined their impact on the lysosomal pH in dendritic cells (DCs), antigen degradation, and presentation of peptide:MHC-I complexes to antigen-specific CD8+ T-cells. To achieve this, we have used 3β-[N-(N′,N′-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) as the prototypical components of CLs with tertiary amine groups and compared the effect of CLs and anionic liposomes on lysosomal pH, antigen degradation, and cross-presentation by DCs. Our results showed that CLs, but not anionic liposomes, elevated the lysosomal pH in DCs and reduced antigen degradation, thereby promoting cross-presentation and cross-priming of CD8+ T-cell responses. These studies shed new light on CL-mediated cross-presentation and suggest that intracellular fate of vaccine components and subsequent immunological responses can be controlled by rational design of nanomaterials. PMID:28243087

  16. Measuring antigen presentation in mouse brain endothelial cells ex vivo and in vitro.

    PubMed

    Howland, Shanshan W; Gun, Sin Yee; Claser, Carla; Poh, Chek Meng; Rénia, Laurent

    2015-12-01

    We have recently demonstrated that brain endothelial cells cross-present parasite antigen during mouse experimental cerebral malaria (ECM). Here we describe a 2-d protocol to detect cross-presentation by isolating the brain microvessels and incubating them with a reporter cell line that expresses lacZ upon detection of the relevant peptide-major histocompatibility complex. After X-gal staining, a typical positive result consists of hundreds of blue spots, compared with fewer than 20 spots from a naive brain. The assay is generalizable to other disease contexts by using reporter cells that express appropriate specific T cell receptors. Also described is the protocol for culturing endothelial cells from brain microvessels isolated from naive mice. After 7-10 d, an in vitro cross-presentation assay can be performed by adding interferon-γ, antigen (e.g., Plasmodium berghei-infected red blood cells) and reporter cells in sequence over 3 d. This is useful for comparing different antigen forms or for probing the effects of various interventions.

  17. COMPUTER SUPPORT SYSTEMS FOR ESTIMATING CHEMICAL TOXICITY: PRESENT CAPABILITIES AND FUTURE TRENDS

    EPA Science Inventory

    Computer Support Systems for Estimating Chemical Toxicity: Present Capabilities and Future Trends

    A wide variety of computer-based artificial intelligence (AI) and decision support systems exist currently to aid in the assessment of toxicity for environmental chemicals. T...

  18. COMPUTER SUPPORT SYSTEMS FOR ESTIMATING CHEMICAL TOXICITY: PRESENT CAPABILITIES AND FUTURE TRENDS

    EPA Science Inventory

    Computer Support Systems for Estimating Chemical Toxicity: Present Capabilities and Future Trends

    A wide variety of computer-based artificial intelligence (AI) and decision support systems exist currently to aid in the assessment of toxicity for environmental chemicals. T...

  19. Interferon regulatory factor 8 regulates pathways for antigen presentation in myeloid cells and during tuberculosis.

    PubMed

    Marquis, Jean-François; Kapoustina, Oxana; Langlais, David; Ruddy, Rebecca; Dufour, Catherine Rosa; Kim, Bae-Hoon; MacMicking, John D; Giguère, Vincent; Gros, Philippe

    2011-06-01

    IRF8 (Interferon Regulatory Factor 8) plays an important role in defenses against intracellular pathogens, including several aspects of myeloid cells function. It is required for ontogeny and maturation of macrophages and dendritic cells, for activation of anti-microbial defenses, and for production of the Th1-polarizing cytokine interleukin-12 (IL-12) in response to interferon gamma (IFNγ) and protection against infection with Mycobacterium tuberculosis. The transcriptional programs and cellular pathways that are regulated by IRF8 in response to IFNγ and that are important for defenses against M. tuberculosis are poorly understood. These were investigated by transcript profiling and chromatin immunoprecipitation on microarrays (ChIP-chip). Studies in primary macrophages identified 368 genes that are regulated by IRF8 in response to IFNγ/CpG and that behave as stably segregating expression signatures (eQTLs) in F2 mice fixed for a wild-type or mutant allele at IRF8. A total of 319 IRF8 binding sites were identified on promoters genome-wide (ChIP-chip) in macrophages treated with IFNγ/CpG, defining a functional G/AGAAnTGAAA motif. An analysis of the genes bearing a functional IRF8 binding site, and showing regulation by IFNγ/CpG in macrophages and/or in M. tuberculosis-infected lungs, revealed a striking enrichment for the pathways of antigen processing and presentation, including multiple structural and enzymatic components of the Class I and Class II MHC (major histocompatibility complex) antigen presentation machinery. Also significantly enriched as IRF8 targets are the group of endomembrane- and phagosome-associated small GTPases of the IRG (immunity-related GTPases) and GBP (guanylate binding proteins) families. These results identify IRF8 as a key regulator of early response pathways in myeloid cells, including phagosome maturation, antigen processing, and antigen presentation by myeloid cells.

  20. Surface-Engineering of Red Blood Cells as Artificial Antigen Presenting Cells Promising for Cancer Immunotherapy.

    PubMed

    Sun, Xiaoqi; Han, Xiao; Xu, Ligeng; Gao, Min; Xu, Jun; Yang, Rong; Liu, Zhuang

    2017-09-01

    The development of artificial antigen presenting cells (aAPCs) to mimic the functions of APCs such as dendritic cells (DCs) to stimulate T cells and induce antitumor immune responses has attracted substantial interests in cancer immunotherapy. In this work, a unique red blood cell (RBC)-based aAPC system is designed by engineering antigen peptide-loaded major histocompatibility complex-I and CD28 activation antibody on RBC surface, which are further tethered with interleukin-2 (IL2) as a proliferation and differentiation signal. Such RBC-based aAPC-IL2 (R-aAPC-IL2) can not only provide a flexible cell surface with appropriate biophysical parameters, but also mimic the cytokine paracrine delivery. Similar to the functions of matured DCs, the R-aAPC-IL2 cells can facilitate the proliferation of antigen-specific CD8+ T cells and increase the secretion of inflammatory cytokines. As a proof-of-concept, we treated splenocytes from C57 mice with R-aAPC-IL2 and discovered those splenocytes induced significant cancer-cell-specific lysis, implying that the R-aAPC-IL2 were able to re-educate T cells and induce adoptive immune response. This work thus presents a novel RBC-based aAPC system which can mimic the functions of antigen presenting DCs to activate T cells, promising for applications in adoptive T cell transfer or even in direct activation of circulating T cells for cancer immunotherapy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Dendritic Cells Take up and Present Antigens from Viable and Apoptotic Polymorphonuclear Leukocytes

    PubMed Central

    Alfaro, Carlos; Suarez, Natalia; Oñate, Carmen; Perez-Gracia, Jose L.; Martinez-Forero, Ivan; Hervas-Stubbs, Sandra; Rodriguez, Inmaculada; Perez, Guiomar; Bolaños, Elixabet; Palazon, Asis; de Sanmamed, Miguel Fernandez; Morales-Kastresana, Aizea; Gonzalez, Alvaro; Melero, Ignacio

    2011-01-01

    Dendritic cells (DC) are endowed with the ability to cross-present antigens from other cell types to cognate T cells. DC are poised to meet polymorphonuclear leukocytes (PMNs) as a result of being co-attracted by interleukin-8 (IL-8), for instance as produced by tumor cells or infected tissue. Human monocyte-derived and mouse bone marrow-derived DC can readily internalize viable or UV-irradiated PMNs. Such internalization was abrogated at 4°C and partly inhibited by anti-CD18 mAb. In mice, DC which had internalized PMNs containing electroporated ovalbumin (OVA) protein, were able to cross-present the antigen to CD8 (OT-1) and CD4 (OT-2) TCR-transgenic T cells. Moreover, in humans, tumor cell debris is internalized by PMNs and the tumor-cell material can be subsequently taken up from the immunomagnetically re-isolated PMNs by DC. Importantly, if human neutrophils had endocytosed bacteria, they were able to trigger the maturation program of the DC. Moreover, when mouse PMNs with E. coli in their interior are co-injected in the foot pad with DC, many DC loaded with fluorescent material from the PMNs reach draining lymph nodes. Using CT26 (H-2d) mouse tumor cells, it was observed that if tumor cells are intracellularly loaded with OVA protein and UV-irradiated, they become phagocytic prey of H-2d PMNs. If such PMNs, that cannot present antigens to OT-1 T cells, are immunomagnetically re-isolated and phagocytosed by H-2b DC, such DC productively cross-present OVA antigen determinants to OT-1 T cells. Cross-presentation to adoptively transferred OT-1 lymphocytes at draining lymph nodes also take place when OVA-loaded PMNs (H-2d) are coinjected in the footpad of mice with autologous DC (H-2b). In summary, our results indicate that antigens phagocytosed by short-lived PMNs can be in turn internalized and productively cross-presented by DC. PMID:22206007

  2. Direct binding of a myasthenia gravis related epitope to MHC class II molecules on living murine antigen-presenting cells.

    PubMed Central

    Mozes, E; Dayan, M; Zisman, E; Brocke, S; Licht, A; Pecht, I

    1989-01-01

    MHC gene products present antigenic epitopes to the antigen receptor on T cells. Nevertheless, direct binding of such epitopes to MHC class II proteins on normal living antigen-presenting cells (APCs) has not yet been demonstrated. We have previously shown a significant difference in the ability of T cells of myasthenia gravis (MG) patients to proliferate in response to the synthetic peptide p195-212 of the human acetylcholine receptor (AChR) alpha-subunit in comparison to healthy controls. The observed proliferative responses correlated significantly with HLA-DR5. Moreover, lymph node cells of various mouse strains that were primed with the T cell epitope, p195-212, were found to proliferate to different extents. To investigate these observations further, we designed an assay for direct binding of p195-212 to MHC class II proteins on the surface of freshly prepared splenic adherent cells. Binding of a biotinylated p195-212 was monitored using phycoerythrin-avidin by flow cytometry. Fifteen to sixty per cent of the cells were labeled following incubation with the biotinylated peptide. Binding was observed only to splenic adherent cells derived from mouse strains of which T cells were capable of proliferating in response to p195-212. The binding specificity, in terms of epitope structure and its site of interaction on the cells, was shown by its inhibition with an excess of the unlabeled peptide or with the relevant monoclonal anti-I-A antibodies. These results constitute the first direct evidence for the specific binding of a T cell epitope to live APC. PMID:2480232

  3. ImmunoChip study implicates antigen presentation to T cells in narcolepsy.

    PubMed

    Faraco, Juliette; Lin, Ling; Kornum, Birgitte Rahbek; Kenny, Eimear E; Trynka, Gosia; Einen, Mali; Rico, Tom J; Lichtner, Peter; Dauvilliers, Yves; Arnulf, Isabelle; Lecendreux, Michel; Javidi, Sirous; Geisler, Peter; Mayer, Geert; Pizza, Fabio; Poli, Francesca; Plazzi, Giuseppe; Overeem, Sebastiaan; Lammers, Gert Jan; Kemlink, David; Sonka, Karel; Nevsimalova, Sona; Rouleau, Guy; Desautels, Alex; Montplaisir, Jacques; Frauscher, Birgit; Ehrmann, Laura; Högl, Birgit; Jennum, Poul; Bourgin, Patrice; Peraita-Adrados, Rosa; Iranzo, Alex; Bassetti, Claudio; Chen, Wei-Min; Concannon, Patrick; Thompson, Susan D; Damotte, Vincent; Fontaine, Bertrand; Breban, Maxime; Gieger, Christian; Klopp, Norman; Deloukas, Panos; Wijmenga, Cisca; Hallmayer, Joachim; Onengut-Gumuscu, Suna; Rich, Stephen S; Winkelmann, Juliane; Mignot, Emmanuel

    2013-01-01

    Recent advances in the identification of susceptibility genes and environmental exposures provide broad support for a post-infectious autoimmune basis for narcolepsy/hypocretin (orexin) deficiency. We genotyped loci associated with other autoimmune and inflammatory diseases in 1,886 individuals with hypocretin-deficient narcolepsy and 10,421 controls, all of European ancestry, using a custom genotyping array (ImmunoChip). Three loci located outside the Human Leukocyte Antigen (HLA) region on chromosome 6 were significantly associated with disease risk. In addition to a strong signal in the T cell receptor alpha (TRA@), variants in two additional narcolepsy loci, Cathepsin H (CTSH) and Tumor necrosis factor (ligand) superfamily member 4 (TNFSF4, also called OX40L), attained genome-wide significance. These findings underline the importance of antigen presentation by HLA Class II to T cells in the pathophysiology of this autoimmune disease.

  4. ImmunoChip Study Implicates Antigen Presentation to T Cells in Narcolepsy

    PubMed Central

    Kornum, Birgitte Rahbek; Kenny, Eimear E.; Trynka, Gosia; Einen, Mali; Rico, Tom J.; Lichtner, Peter; Dauvilliers, Yves; Arnulf, Isabelle; Lecendreux, Michel; Javidi, Sirous; Geisler, Peter; Mayer, Geert; Pizza, Fabio; Poli, Francesca; Plazzi, Giuseppe; Overeem, Sebastiaan; Lammers, Gert Jan; Kemlink, David; Sonka, Karel; Nevsimalova, Sona; Rouleau, Guy; Desautels, Alex; Montplaisir, Jacques; Frauscher, Birgit; Ehrmann, Laura; Högl, Birgit; Jennum, Poul; Bourgin, Patrice; Peraita-Adrados, Rosa; Iranzo, Alex; Bassetti, Claudio; Chen, Wei-Min; Concannon, Patrick; Thompson, Susan D.; Damotte, Vincent; Fontaine, Bertrand; Breban, Maxime; Gieger, Christian; Klopp, Norman; Deloukas, Panos; Wijmenga, Cisca; Hallmayer, Joachim; Onengut-Gumuscu, Suna; Rich, Stephen S.; Winkelmann, Juliane; Mignot, Emmanuel

    2013-01-01

    Recent advances in the identification of susceptibility genes and environmental exposures provide broad support for a post-infectious autoimmune basis for narcolepsy/hypocretin (orexin) deficiency. We genotyped loci associated with other autoimmune and inflammatory diseases in 1,886 individuals with hypocretin-deficient narcolepsy and 10,421 controls, all of European ancestry, using a custom genotyping array (ImmunoChip). Three loci located outside the Human Leukocyte Antigen (HLA) region on chromosome 6 were significantly associated with disease risk. In addition to a strong signal in the T cell receptor alpha (TRA@), variants in two additional narcolepsy loci, Cathepsin H (CTSH) and Tumor necrosis factor (ligand) superfamily member 4 (TNFSF4, also called OX40L), attained genome-wide significance. These findings underline the importance of antigen presentation by HLA Class II to T cells in the pathophysiology of this autoimmune disease. PMID:23459209

  5. An Overview of B-1 Cells as Antigen-Presenting Cells

    PubMed Central

    Popi, Ana F.; Longo-Maugéri, Ieda M.; Mariano, Mario

    2016-01-01

    The role of B cells as antigen-presenting cells (APCs) has been extensively studied, mainly in relation to the activation of memory T cells. Considering the B cell subtypes, the role of B-1 cells as APCs is beginning to be explored. Initially, it was described that B-1 cells are activated preferentially by T-independent antigens. However, some reports demonstrated that these cells are also involved in a T-dependent response. The aim of this review is to summarize information about the ability of B-1 cells to play a role as APCs and to briefly discuss the role of the BCR and toll-like receptor signals in this process. Furthermore, some characteristics of B-1 cells, such as natural IgM production and phagocytic ability, could interfere in the participation of these cells in the onset of an adaptive response. PMID:27148259

  6. Understanding the immunogenicity and antigenicity of nanomaterials: Past, present and future.

    PubMed

    Ilinskaya, Anna N; Dobrovolskaia, Marina A

    2016-05-15

    Nanoparticle immunogenicity and antigenicity have been under investigation for many years. During the past decade, significant progress has been made in understanding what makes a nanoparticle immunogenic, how immune cells respond to nanoparticles, what consequences of nanoparticle-specific antibody formation exist and how they challenge the application of nanoparticles for drug delivery. Moreover, it has been recognized that accidental contamination of therapeutic protein formulations with nanosized particulate materials may contribute to the immunogenicity of this type of biotechnology products. While the immunological properties of engineered nanomaterials and their application as vaccine carriers and adjuvants have been given substantial consideration in the current literature, little attention has been paid to nanoparticle immuno- and antigenicity. To fill in this gap, we herein provide an overview of this subject to highlight the current state of the field, review past and present research, and discuss future research directions. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. A Systems Approach to Understand Antigen Presentation and the Immune Response.

    PubMed

    Dudek, Nadine L; Croft, Nathan P; Schittenhelm, Ralf B; Ramarathinam, Sri H; Purcell, Anthony W

    2016-01-01

    The mammalian immune system has evolved to respond to pathogenic, environmental, and cellular changes in order to maintain the health of the host. These responses include the comparatively primitive innate immune response, which represents a rapid and relatively nonspecific reaction to challenge by pathogens and the more complex cellular adaptive immune response. This adaptive response evolves with the pathogenic challenge, involves the cross talk of several cell types, and is highly specific to the pathogen due to the liberation of peptide antigens and their presentation on the surface of affected cells. Together these two forms of immunity provide a surveillance mechanism for the system-wide scrutiny of cellular function, environment, and health. As such the immune system is best understood at a systems biology level, and studies that combine gene expression, protein expression, and liberation of peptides for antigen presentation can be combined to provide a detailed understanding of immunity. This chapter details our experience in identifying peptide antigens and combining this information with more traditional proteomics approaches to understand the generation of immune responses on a holistic level.

  8. Blood coagulation protein fibrinogen promotes autoimmunity and demyelination via chemokine release and antigen presentation

    PubMed Central

    Ryu, Jae Kyu; Petersen, Mark A.; Murray, Sara G.; Baeten, Kim M.; Meyer-Franke, Anke; Chan, Justin P.; Vagena, Eirini; Bedard, Catherine; Machado, Michael R.; Coronado, Pamela E. Rios; Prod'homme, Thomas; Charo, Israel F.; Lassmann, Hans; Degen, Jay L.; Zamvil, Scott S.; Akassoglou, Katerina

    2015-01-01

    Autoimmunity and macrophage recruitment into the central nervous system (CNS) are critical determinants of neuroinflammatory diseases. However, the mechanisms that drive immunological responses targeted to the CNS remain largely unknown. Here we show that fibrinogen, a central blood coagulation protein deposited in the CNS after blood–brain barrier disruption, induces encephalitogenic adaptive immune responses and peripheral macrophage recruitment into the CNS leading to demyelination. Fibrinogen stimulates a unique transcriptional signature in CD11b+ antigen-presenting cells inducing the recruitment and local CNS activation of myelin antigen-specific Th1 cells. Fibrinogen depletion reduces Th1 cells in the multiple sclerosis model, experimental autoimmune encephalomyelitis. Major histocompatibility complex (MHC) II-dependent antigen presentation, CXCL10- and CCL2-mediated recruitment of T cells and macrophages, respectively, are required for fibrinogen-induced encephalomyelitis. Inhibition of the fibrinogen receptor CD11b/CD18 protects from all immune and neuropathologic effects. Our results show that the final product of the coagulation cascade is a key determinant of CNS autoimmunity. PMID:26353940

  9. Pollen-induced antigen presentation by mesenchymal stem cells and T cells from allergic rhinitis.

    PubMed

    Desai, Mauli B; Gavrilova, Tatyana; Liu, Jianjun; Patel, Shyam A; Kartan, Saritha; Greco, Steven J; Capitle, Eugenio; Rameshwar, Pranela

    2013-10-01

    Mesenchymal stem cells (MSCs) are promising cellular suppressor of inflammation. This function of MSCs is partly due to their licensing by inflammatory mediators. In cases with reduced inflammation, MSCs could become immune-enhancer cells. MSCs can suppress the inflammatory response of antigen-challenged lymphocytes from allergic asthma. Although allergic rhinitis (AR) is also an inflammatory response, it is unclear if MSCs can exert similar suppression. This study investigated the immune effects (suppressor vs enhancer) of MSCs on allergen-stimulated lymphocytes from AR subjects (grass or weed allergy). In contrast to subjects with allergic asthma, MSCs caused a significant (P<0.05) increase in the proliferation of antigen-challenged lymphocytes from AR subjects. The increase in lymphocyte proliferation was caused by the MSCs presenting the allergens to CD4(+) T cells (antigen-presenting cells (APCs)). This correlated with increased production of inflammatory cytokines from T cells, and increased expressions of major histocompatibility complex (MHC)-II and CD86 on MSCs. The specificity of APC function was demonstrated in APC assay using MSCs that were knocked down for the master regulator of MHC-II transcription, CIITA. The difference in the effects of MSCs on allergic asthma and AR could not be explained by the sensitivity to the allergen, based on skin tests. Thus, we deduced that the contrasting immune effects of MSCs for antigen-challenged lymphocytes on AR and allergic asthma could be disease specific. It is possible that the enhanced inflammation from asthma might be required to license the MSCs to become suppressor cells. This study underscores the need for robust preclinical studies to effectively translate MSCs for any inflammatory disorder.

  10. Loss of antigen-presenting molecules (MHC class I and TAP-1) in lung cancer.

    PubMed Central

    Korkolopoulou, P.; Kaklamanis, L.; Pezzella, F.; Harris, A. L.; Gatter, K. C.

    1996-01-01

    Presentation of endogenous antigenic peptides to cytotoxic T lymphocytes is mediated by the major histocompatibility complex (MHC) class I molecules. For the stable assembly of MHC class I complex it is necessary that the antigenic peptide is transported by the MHC-encoded transporters TAP-1 and TAP-2 into a pre-Golgi region. T-cell-mediated host-vs-tumour response might therefore depend on the presence of these molecules on tumour cells. The presence of MHC class I antigens and TAP-1 was studied in a series of 93 resection specimens of non-small-cell lung carcinomas (NSCLCs) by immunohistochemical methods using antibodies against the assembled class I molecule, beta 2-microglobulin (beta 2-m), heavy-chain A locus, A2 allele and TAP-1 protein. Eighty-six patients were included in the survival analysis. Total loss of class I molecule was observed in 38% of the cases and was usually accompanied by loss of beta 2-m and of heavy chain A locus. Selective loss of A locus was seen in 8.3% and of A2 allele in 27% of the cases. TAP-1 loss was always combined with beta 2-m and/or heavy chain A locus loss. No correlation was found between the expressional status of any of the above molecules, including the selective A2 allelic loss and histological type, degree of differentiation, tumoral stage, nodal stage and survival. Our findings suggest that loss of antigen-presenting molecules (including both MHC class I alleles and TAP-1) is a frequent event in lung cancer. However, the immunophenotypic profile of MHC class I and TAP-1 seems to be unrelated in vivo to the phenotype, growth or survival of NSCLC. Images Figure 1 PMID:8546899

  11. Nanoengineering approaches to the design of artificial antigen-presenting cells

    PubMed Central

    Sunshine, Joel C; Green, Jordan J

    2014-01-01

    Artificial antigen-presenting cells (aAPCs) have shown great initial promise for ex vivo activation of cytotoxic T cells. The development of aAPCs has focused mainly on the choice of proteins to use for surface presentation to T cells when conjugated to various spherical, microscale particles. We review here biomimetic nanoengineering approaches that have been applied to the development of aAPCs that move beyond initial concepts about aAPC development. This article also discusses key technologies that may be enabling for the development of nano- and micro-scale aAPCs with nanoscale features, and suggests several future directions for the field. PMID:23837856

  12. Biomimetic biodegradable artificial antigen presenting cells synergize with PD-1 blockade to treat melanoma.

    PubMed

    Kosmides, A K; Meyer, R A; Hickey, J W; Aje, K; Cheung, K N; Green, J J; Schneck, J P

    2017-02-01

    Biomimetic materials that target the immune system and generate an anti-tumor responses hold promise in augmenting cancer immunotherapy. These synthetic materials can be engineered and optimized for their biodegradability, physical parameters such as shape and size, and controlled release of immune-modulators. As these new platforms enter the playing field, it is imperative to understand their interaction with existing immunotherapies since single-targeted approaches have limited efficacy. Here, we investigate the synergy between a PLGA-based artificial antigen presenting cell (aAPC) and a checkpoint blockade molecule, anti-PD1 monoclonal antibody (mAb). The combination of antigen-specific aAPC-based activation and anti-PD-1 mAb checkpoint blockade induced the greatest IFN-γ secretion by CD8+ T cells in vitro. Combination treatment also acted synergistically in an in vivo murine melanoma model to result in delayed tumor growth and extended survival, while either treatment alone had no effect. This was shown mechanistically to be due to decreased PD-1 expression and increased antigen-specific proliferation of CD8+ T cells within the tumor microenvironment and spleen. Thus, biomaterial-based therapy can synergize with other immunotherapies and motivates the translation of biomimetic combinatorial treatments.

  13. Killer artificial antigen-presenting cells: a novel strategy to delete specific T cells.

    PubMed

    Schütz, Christian; Fleck, Martin; Mackensen, Andreas; Zoso, Alessia; Halbritter, Dagmar; Schneck, Jonathan P; Oelke, Mathias

    2008-04-01

    Several cell-based immunotherapy strategies have been developed to specifically modulate T cell-mediated immune responses. These methods frequently rely on the utilization of tolerogenic cell-based antigen-presenting cells (APCs). However, APCs are highly sensitive to cytotoxic T-cell responses, thus limiting their therapeutic capacity. Here, we describe a novel bead-based approach to modulate T-cell responses in an antigen-specific fashion. We have generated killer artificial APCs (kappaaAPCs) by coupling an apoptosis-inducing alpha-Fas (CD95) IgM mAb together with HLA-A2 Ig molecules onto beads. These kappaaAPCs deplete targeted antigen-specific T cells in a Fas/Fas ligand (FasL)-dependent fashion. T-cell depletion in cocultures is rapidly initiated (30 minutes), dependent on the amount of kappaaAPCs and independent of activation-induced cell death (AICD). kappaaAPCs represent a novel technology that can control T cell-mediated immune responses, and therefore has potential for use in treatment of autoimmune diseases and allograft rejection.

  14. The dominant role of CD8+ dendritic cells in cross-presentation is not dictated by antigen capture

    PubMed Central

    Schnorrer, Petra; Behrens, Georg M. N.; Wilson, Nicholas S.; Pooley, Joanne L.; Smith, Christopher M.; El-Sukkari, Dima; Davey, Gayle; Kupresanin, Fiona; Li, Ming; Maraskovsky, Eugene; Belz, Gabrielle T.; Carbone, Francis R.; Shortman, Ken; Heath, William R.; Villadangos, Jose A.

    2006-01-01

    Mouse spleens contain three populations of conventional (CD11chigh) dendritic cells (DCs) that play distinct functions. The CD8+ DC are unique in that they can present exogenous antigens on their MHC class I molecules, a process known as cross-presentation. It is unclear whether this special ability is because only the CD8+ DC can capture the antigens used in cross-presentation assays, or because this is the only DC population that possesses specialized machinery for cross-presentation. To solve this important question we examined the splenic DC subsets for their ability to both present via MHC class II molecules and cross-present via MHC class I using four different forms of the model antigen ovalbumin (OVA). These forms include a cell-associated form, a soluble form, OVA expressed in bacteria, or OVA bound to latex beads. With the exception of bacterial antigen, which was poorly cross-presented by all DC, all antigenic forms were cross-presented much more efficiently by the CD8+ DC. This pattern could not be attributed simply to a difference in antigen capture because all DC subsets presented the antigen via MHC class II. Indeed, direct assessments of endocytosis showed that CD8+ and CD8− DC captured comparable amounts of soluble and bead-associated antigen, yet only the CD8+ DC cross-presented these antigenic forms. Our results indicate that cross-presentation requires specialized machinery that is expressed by CD8+ DC but largely absent from CD8− DC. This conclusion has important implications for the design of vaccination strategies based on antigen targeting to DC. PMID:16807294

  15. The activation of the adaptive immune system: cross-talk between antigen-presenting cells, T cells and B cells.

    PubMed

    den Haan, Joke M M; Arens, Ramon; van Zelm, Menno C

    2014-12-01

    The adaptive immune system consists of T and B cells that express clonally distributed antigen receptors. To achieve functional adaptive immune responses, antigen-specific T cell populations are stimulated by professional antigen-presenting cells like dendritic cells (DCs), which provide crucial stimulatory signals for efficient expansion and development of effector functions. Antigen-specific B cells receive costimulatory signals from helper T cells to stimulate affinity maturation and isotype switching. Here we elaborate on the interactions between DCs, T cells and B cells, and on the important signals for efficient induction of adaptive immune responses. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Aptamers directly radiolabeled with technetium-99m as a potential agent capable of identifying carcinoembryonic antigen (CEA) in tumor cells T84.

    PubMed

    Correa, Cristiane Rodrigues; de Barros, André Luís Branco; Ferreira, Carolina de Aguiar; de Goes, Alfredo Miranda; Cardoso, Valbert Nascimento; de Andrade, Antero Silva Ribeiro

    2014-04-15

    Aptamers are small oligonucleotides that are selected to bind with high affinity and specificity to a target molecule. Aptamers are emerging as a new class of molecules for radiopharmaceutical development. In this study a new method to radiolabel aptamers with technetium-99m ((99m)Tc) was developed. Two aptamers (Apt3 and Apt3-amine) selected against the carcinoembryonic antigen (CEA) were used. Labeling was done by the direct method and the developed complex was subjected to quality control tests. Radiochemical purity and stability were monitored by Thin Layer Chromatography. Binding and specificity assays were carried out in the T84 cell line (CEA+) to evaluate tumor affinity and specificity after radiolabeling. Aptamers were successfully labeled with (99m)Tc in high radiochemical yields, showing in vitro stability in presence of plasma and cystein. In binding assays the radiolabeled aptamer Apt3-amine showed the highest affinity to T84 cells. When evaluated with HeLa cells (CEA-), lower uptake was observed, suggesting high specificity for this aptamer. These results suggest that the Apt3-amine aptamer directly labeled with (99m)Tc could be considered a promising agent capable of identifying the carcinoembryonic antigen (CEA) present in tumor cells.

  17. Human Plasmacytoid Dendritic Cells Efficiently Capture HIV-1 Envelope Glycoproteins via CD4 for Antigen Presentation

    PubMed Central

    Sandgren, Kerrie J; Smed-Sörensen, Anna; Forsell, Mattias N; Soldemo, Martina; Adams, William C; Liang, Frank; Perbeck, Leif; Koup, Richard A; Wyatt, Richard T; Hedestam, Gunilla B Karlsson; Loré, Karin

    2013-01-01

    Advances in HIV-1 vaccine clinical trials and preclinical research indicate that the virus envelope glycoproteins (Env) are likely to be an essential component of a prophylactic vaccine. Efficient antigen uptake and presentation by dendritic cells (DCs) is important for strong CD4+ T helper cell responses and the development of effective humoral immune responses. Here, we examined the capacity of distinct primary human DC subsets to internalise and present recombinant Env to CD4+ T cells. Consistent with their specific receptor expression, skin DCs bound and internalised Env via C-type lectin receptors (CLRs) while blood DC subsets, including CD1c+ myeloid DCs (MDCs), CD123+ plasmacytoid DCs (PDCs) and CD141+ DCs exhibited a restricted repertoire of CLRs and relied on CD4 for uptake of Env. Despite a generally poor capacity for antigen uptake compared to MDCs, the high expression of CD4 on PDCs allowed them to bind and internalise Env very efficiently. CD4-mediated uptake delivered Env to EEA1+ endosomes that progressed to Lamp1+ and MHC class II+ lysosomes where internalised Env was degraded rapidly. Finally, all three blood DC subsets were able to internalise an Env-CMV pp65 fusion protein via CD4 and stimulate pp65-specific CD4+ T cells. Thus, in the in vitro systems described here, CD4-mediated uptake of Env is a functional pathway leading to antigen presentation and this may therefore be a mechanism utilised by blood DCs, including PDCs, for generating immune responses to Env-based vaccines. PMID:23729440

  18. Survival and signaling changes in antigen presenting cell subsets after radiation

    NASA Astrophysics Data System (ADS)

    Parker, Jennifer Janell

    Radiation therapy is a widely used cancer treatment that has the potential to influence anti-tumor immune responses. Both myeloablative and non-myeloablative radiation are often used as part of preparatory regimens for hematopoetic stem cell transplantation, in combination with other chemotherapy or immuno-modulatory (e.g. Anti-thymocyte globulin (ATG)) therapies for both cytotoxic and immune modulatory purposes. However, the mechanisms responsible for the effect of radiation on antigen presenting cell (APC) responsiveness and radioresistance are poorly understood. The first studies described in this thesis were designed to identify and characterize early radiation-induced signaling changes in antigen presenting cells and to determine the effects of these signaling changes on APC receptor expression and function. The NFkappaB pathway in antigen presenting cells was chosen for study because it is activated by radiation in a wide range of other cell types and plays a vital role in the maintenance and regulation of the immune system. The effects of therapeutically relevant doses radiation (2 and 20 Gy) were compared at various timepoints in the human monocytic cell line (U937) using phospho-flow cytometry staining methods and cytometric analysis. These studies demonstrated that radiation-induced changes in the phosphorylation state of NFkappaB family members that were p53 independent. However, these changes were dependent upon activation of ATM in response to single or double-stranded breaks in DNA, as shown in experiments using an inhibitor of ATM and ATM siRNA knockdown U937 cells. In addition, studies examining the effect of radiation on co-stimulatory receptors with and without inhibition of the NFkappaB pathway via phospho-flow cytometry revealed that radiation-induced phosphorylation of NEMO promoted the activation and functional maturation of U937 cells. Furthermore, functional studies using both phospho-flow cytometry and/or mixed lymphocyte reactions to

  19. Ly6C+ monocyte efferocytosis and cross-presentation of cell-associated antigens

    PubMed Central

    Larson, S R; Atif, S M; Gibbings, S L; Thomas, S M; Prabagar, M G; Danhorn, T; Leach, S M; Henson, P M; Jakubzick, C V

    2016-01-01

    Recently it was shown that circulating Ly6C+ monocytes traffic from tissue to the draining lymph nodes (LNs) with minimal alteration in their overall phenotype. Furthermore, in the steady state, Ly6C+ monocytes are as abundant as classical dendritic cells (DCs) within the draining LNs, and even more abundant during inflammation. However, little is known about the functional roles of constitutively trafficking Ly6C+ monocytes. In this study we investigated whether Ly6C+ monocytes can efferocytose (acquire dying cells) and cross-present cell-associated antigen, a functional property particularly attributed to Batf3+ DCs. We demonstrated that Ly6C+ monocytes intrinsically efferocytose and cross-present cell-associated antigen to CD8+ T cells. In addition, efferocytosis was enhanced upon direct activation of the Ly6C+ monocytes through its corresponding TLRs, TLR4 and TLR7. However, only ligation of TLR7, and not TLR4, enhanced cross-presentation by Ly6C+ monocytes. Overall, this study outlines two functional roles, among others, that Ly6C+ monocytes have during an adaptive immune response. PMID:26990659

  20. A Lipid Based Antigen Delivery System Efficiently Facilitates MHC Class-I Antigen Presentation in Dendritic Cells to Stimulate CD8(+) T Cells.

    PubMed

    Maji, Mithun; Mazumder, Saumyabrata; Bhattacharya, Souparno; Choudhury, Somsubhra Thakur; Sabur, Abdus; Shadab, Md; Bhattacharya, Pradyot; Ali, Nahid

    2016-06-02

    The most effective strategy for protection against intracellular infections such as Leishmania is vaccination with live parasites. Use of recombinant proteins avoids the risks associated with live vaccines. However, due to low immunogenicity, they fail to trigger T cell responses particularly of CD8(+) cells requisite for persistent immunity. Previously we showed the importance of protein entrapment in cationic liposomes and MPL as adjuvant for elicitation of CD4(+) and CD8(+) T cell responses for long-term protection. In this study we investigated the role of cationic liposomes on maturation and antigen presentation capacity of dendritic cells (DCs). We observed that cationic liposomes were taken up very efficiently by DCs and transported to different cellular sites. DCs activated with liposomal rgp63 led to efficient presentation of antigen to specific CD4(+) and CD8(+) T cells. Furthermore, lymphoid CD8(+) T cells from liposomal rgp63 immunized mice demonstrated better proliferative ability when co-cultured ex vivo with stimulated DCs. Addition of MPL to vaccine enhanced the antigen presentation by DCs and induced more efficient antigen specific CD8(+) T cell responses when compared to free and liposomal antigen. These liposomal formulations presented to CD8(+) T cells through TAP-dependent MHC-I pathway offer new possibilities for a safe subunit vaccine.

  1. A Lipid Based Antigen Delivery System Efficiently Facilitates MHC Class-I Antigen Presentation in Dendritic Cells to Stimulate CD8+ T Cells

    NASA Astrophysics Data System (ADS)

    Maji, Mithun; Mazumder, Saumyabrata; Bhattacharya, Souparno; Choudhury, Somsubhra Thakur; Sabur, Abdus; Shadab, Md.; Bhattacharya, Pradyot; Ali, Nahid

    2016-06-01

    The most effective strategy for protection against intracellular infections such as Leishmania is vaccination with live parasites. Use of recombinant proteins avoids the risks associated with live vaccines. However, due to low immunogenicity, they fail to trigger T cell responses particularly of CD8+ cells requisite for persistent immunity. Previously we showed the importance of protein entrapment in cationic liposomes and MPL as adjuvant for elicitation of CD4+ and CD8+ T cell responses for long-term protection. In this study we investigated the role of cationic liposomes on maturation and antigen presentation capacity of dendritic cells (DCs). We observed that cationic liposomes were taken up very efficiently by DCs and transported to different cellular sites. DCs activated with liposomal rgp63 led to efficient presentation of antigen to specific CD4+ and CD8+ T cells. Furthermore, lymphoid CD8+ T cells from liposomal rgp63 immunized mice demonstrated better proliferative ability when co-cultured ex vivo with stimulated DCs. Addition of MPL to vaccine enhanced the antigen presentation by DCs and induced more efficient antigen specific CD8+ T cell responses when compared to free and liposomal antigen. These liposomal formulations presented to CD8+ T cells through TAP-dependent MHC-I pathway offer new possibilities for a safe subunit vaccine.

  2. MHC I presentation of Toxoplasma gondii immunodominant antigen does not require Sec22b and is regulated by antigen orientation at the vacuole membrane.

    PubMed

    Buaillon, Célia; Guerrero, Nestor A; Cebrian, Ignacio; Blanié, Sophie; Lopez, Jodie; Bassot, Emilie; Vasseur, Virginie; Santi-Rocca, Julien; Blanchard, Nicolas

    2017-07-01

    The intracellular Toxoplasma gondii parasite replicates within a parasitophorous vacuole (PV). T. gondii secretes proteins that remain soluble in the PV space, are inserted into PV membranes or are exported beyond the PV boundary. In addition to supporting T. gondii growth, these proteins can be processed and presented by MHC I for CD8(+) T-cell recognition. Yet it is unclear whether membrane binding influences the processing pathways employed and if topology of membrane antigens impacts their MHC I presentation. Here we report that the MHC I pathways of soluble and membrane-bound antigens differ in their requirement for host ER recruitment. In contrast to the soluble SAG1-OVA model antigen, we find that presentation of the membrane-bound GRA6 is independent from the SNARE Sec22b, a key molecule for transfer of host endoplasmic reticulum components onto the PV. Using parasites modified to secrete a transmembrane antigen with opposite orientations, we further show that MHC I presentation is highly favored when the C-terminal epitope is exposed to the host cell cytosol, which corresponds to GRA6 natural orientation. Our data suggest that the biochemical properties of antigens released by intracellular pathogens critically guide their processing pathway and are valuable parameters to consider for vaccination strategies. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Collective Genetic Interaction Effects and the Role of Antigen-Presenting Cells in Autoimmune Diseases

    PubMed Central

    Woo, Hyung Jun; Yu, Chenggang; Reifman, Jaques

    2017-01-01

    Autoimmune diseases occur when immune cells fail to develop or lose their tolerance toward self and destroy body’s own tissues. Both insufficient negative selection of self-reactive T cells and impaired development of regulatory T cells preventing effector cell activation are believed to contribute to autoimmunity. Genetic predispositions center around the major histocompatibility complex (MHC) class II loci involved in antigen presentation, the key determinant of CD4+ T cell activation. Recent studies suggested that variants in the MHC region also exhibit significant non-additive interaction effects. However, collective interactions involving large numbers of single nucleotide polymorphisms (SNPs) contributing to such effects are yet to be characterized. In addition, relatively little is known about the cell-type-specificity of such interactions in the context of cellular pathways. Here, we analyzed type 1 diabetes (T1D) and rheumatoid arthritis (RA) genome-wide association data sets via large-scale, high-performance computations and inferred collective interaction effects involving MHC SNPs using the discrete discriminant analysis. Despite considerable differences in the details of SNP interactions in T1D and RA data, the enrichment pattern of interacting pairs in reference epigenomes was remarkably similar: statistically significant interactions were epigenetically active in cell-type combinations connecting B cells to T cells and intestinal epithelial cells, with both helper and regulatory T cells showing strong disease-associated interactions with B cells. Our results provide direct genetic evidence pointing to the important roles B cells play as antigen-presenting cells toward CD4+ T cells in the context of central and peripheral tolerance. In addition, they are consistent with recent experimental studies suggesting that the repertoire of B cell-specific self-antigens in the thymus are critical to the effective control of corresponding autoimmune activation

  4. Oxidative bioactivation of abacavir in subcellular fractions of human antigen presenting cells.

    PubMed

    Bell, Catherine C; Santoyo Castelazo, Anahi; Yang, Emma L; Maggs, James L; Jenkins, Rosalind E; Tugwood, Jonathan; O'Neill, Paul M; Naisbitt, Dean J; Park, B Kevin

    2013-07-15

    Human exposure to abacavir, a primary alcohol antiretroviral, is associated with the development of immunological drug reactions in individuals carrying the HLA risk allele B*57:01. Interaction of abacavir with antigen presenting cells results in cell activation through an Hsp70-mediated Toll-like receptor pathway and the provision of T-cell antigenic determinants. Abacavir's electrophilic aldehyde metabolites are potential precursors of neoantigens. Herein, we have used mass spectrometry to study the oxidative metabolism of abacavir in EBV-transformed human B-cells. RNA and protein were isolated from the cells and subjected to transcriptomic and mass spectrometric analyses to identify the redox enzymes expressed. Low levels of isomeric abacavir carboxylic acids were detected in subcellular fractions of EBV-transformed human B-cells incubated with abacavir. Metabolite formation was time-dependent but was not reduced by an inhibitor of Class I alcohol dehydrogenases. Relatively high levels of mRNA were detected for several redox enzymes, including alcohol dehydrogenase 5 (Class III), aldehyde dehydrogenases (ALDH3A2, ALDH6A1, and ALDH9A1), CYP1B1, CYP2R1, CYP7B1, and hydroxysteroid dehydrogenase 10. Over 2600 proteins were identified by mass spectrometry. More than 1000 of these proteins exhibited catalytic activity, and 80 were oxido-reductases. This is the first proteomic inventory of enzymes in antigen presenting cells. However, neither of the hepatic alcohol dehydrogenases of Class I which metabolize abacavir in vitro was expressed at the protein level. Nevertheless the metabolic production of abacavir carboxylic acids by B-cell fractions implies abacavir-treated immune cells might be exposed to the drug's protein-reactive aldehyde metabolites in vivo.

  5. STAT3 promotes CD1d-mediated lipid antigen presentation by regulating a critical gene in glycosphingolipid biosynthesis.

    PubMed

    Iyer, Abhirami K; Liu, Jianyun; Gallo, Richard M; Kaplan, Mark H; Brutkiewicz, Randy R

    2015-11-01

    Cytokines that regulate the immune response signal through the Janus kinase / signal transducer and activation of transcription (JAK/STAT) pathway, but whether this pathway can regulate CD1d-mediated lipid antigen presentation to natural killer T (NKT) cells is unknown. Here, we found that STAT3 promotes antigen presentation by CD1d. Antigen-presenting cells (APCs) in which STAT3 expression was inhibited exhibited markedly reduced endogenous lipid antigen presentation to NKT cells without an impact on exogenous lipid antigen presentation by CD1d. Consistent with this observation, in APCs where STAT3 was knocked down, dramatically decreased levels of UDP glucose ceramide glucosyltransferase (UGCG), an enzyme involved in the first step of glycosphingolipid biosynthesis, were observed. Impaired lipid antigen presentation was reversed by ectopic expression of UGCG in STAT3-silenced CD1d(+) APCs. Hence, by controlling a fundamental step in CD1d-mediated lipid antigen presentation, STAT3 signalling promotes innate immune responses driven by CD1d.

  6. Pseudomonas aeruginosa Cif Protein Enhances the Ubiquitination and Proteasomal Degradation of the Transporter Associated with Antigen Processing (TAP) and Reduces Major Histocompatibility Complex (MHC) Class I Antigen Presentation*

    PubMed Central

    Bomberger, Jennifer M.; Ely, Kenneth H.; Bangia, Naveen; Ye, Siying; Green, Kathy A.; Green, William R.; Enelow, Richard I.; Stanton, Bruce A.

    2014-01-01

    Cif (PA2934), a bacterial virulence factor secreted in outer membrane vesicles by Pseudomonas aeruginosa, increases the ubiquitination and lysosomal degradation of some, but not all, plasma membrane ATP-binding cassette transporters (ABC), including the cystic fibrosis transmembrane conductance regulator and P-glycoprotein. The goal of this study was to determine whether Cif enhances the ubiquitination and degradation of the transporter associated with antigen processing (TAP1 and TAP2), members of the ABC transporter family that play an essential role in antigen presentation and intracellular pathogen clearance. Cif selectively increased the amount of ubiquitinated TAP1 and increased its degradation in the proteasome of human airway epithelial cells. This effect of Cif was mediated by reducing USP10 deubiquitinating activity, resulting in increased polyubiquitination and proteasomal degradation of TAP1. The reduction in TAP1 abundance decreased peptide antigen translocation into the endoplasmic reticulum, an effect that resulted in reduced antigen available to MHC class I molecules for presentation at the plasma membrane of airway epithelial cells and recognition by CD8+ T cells. Cif is the first bacterial factor identified that inhibits TAP function and MHC class I antigen presentation. PMID:24247241

  7. Pseudomonas aeruginosa Cif protein enhances the ubiquitination and proteasomal degradation of the transporter associated with antigen processing (TAP) and reduces major histocompatibility complex (MHC) class I antigen presentation.

    PubMed

    Bomberger, Jennifer M; Ely, Kenneth H; Bangia, Naveen; Ye, Siying; Green, Kathy A; Green, William R; Enelow, Richard I; Stanton, Bruce A

    2014-01-03

    Cif (PA2934), a bacterial virulence factor secreted in outer membrane vesicles by Pseudomonas aeruginosa, increases the ubiquitination and lysosomal degradation of some, but not all, plasma membrane ATP-binding cassette transporters (ABC), including the cystic fibrosis transmembrane conductance regulator and P-glycoprotein. The goal of this study was to determine whether Cif enhances the ubiquitination and degradation of the transporter associated with antigen processing (TAP1 and TAP2), members of the ABC transporter family that play an essential role in antigen presentation and intracellular pathogen clearance. Cif selectively increased the amount of ubiquitinated TAP1 and increased its degradation in the proteasome of human airway epithelial cells. This effect of Cif was mediated by reducing USP10 deubiquitinating activity, resulting in increased polyubiquitination and proteasomal degradation of TAP1. The reduction in TAP1 abundance decreased peptide antigen translocation into the endoplasmic reticulum, an effect that resulted in reduced antigen available to MHC class I molecules for presentation at the plasma membrane of airway epithelial cells and recognition by CD8(+) T cells. Cif is the first bacterial factor identified that inhibits TAP function and MHC class I antigen presentation.

  8. Inhibition of CD1d-mediated antigen presentation by the transforming growth factor-β/Smad signalling pathway.

    PubMed

    Bailey, Jennifer C; Iyer, Abhirami K; Renukaradhya, Gourapura J; Lin, Yinling; Nguyen, Hoa; Brutkiewicz, Randy R

    2014-12-01

    CD1d-mediated lipid antigen presentation activates a subset of innate immune lymphocytes called invariant natural killer T (NKT) cells that, by virtue of their potent cytokine production, bridge the innate and adaptive immune systems. Transforming growth factor (TGF-β) is a known immune modulator that can activate the mitogen-activated protein kinase p38; we have previously shown that p38 is a negative regulator of CD1d-mediated antigen presentation. Several studies implicate a role for TGF-β in the activation of p38. Therefore, we hypothesized that TGF-β would impair antigen presentation by CD1d. Indeed, a dose-dependent decrease in CD1d-mediated antigen presentation and impairment of lipid antigen processing was observed in response to TGF-β treatment. However, it was found that this inhibition was not through p38 activation. Instead, Smads 2, 3 and 4, downstream elements of the TGF-β canonical signalling pathway, contributed to the observed effects. In marked contrast to that observed with CD1d, TGF-β was found to enhance MHC class II-mediated antigen presentation. Overall, these results suggest that the canonical TGF-β/Smad pathway negatively regulates an important arm of the host's innate immune responses - CD1d-mediated lipid antigen presentation to NKT cells.

  9. Self-adjuvanted nanovaccine for cancer immunotherapy: Role of lysosomal rupture-induced ROS in MHC class I antigen presentation.

    PubMed

    Wang, Ce; Li, Ping; Liu, Lanlan; Pan, Hong; Li, Hongchang; Cai, Lintao; Ma, Yifan

    2016-02-01

    MHC class I (MHC I) antigen presentation of exogenous antigens (so called "cross presentation") is a central mechanism of CD8(+) cytotoxic T lymphocyte (CTL) responses essential for successful vaccine-based cancer immunotherapy. The present study constructed amphiphilic pH-sensitive galactosyl dextran-retinal (GDR) nanogels for cancer vaccine delivery, in which dextran was conjugated with all-trans retinal (a metabolite of vitamin A) through a pH-sensitive hydrazone bond, followed by galactosylation to acquire dendritic cell (DC)-targeting ability. Our results showed that pH-sensitive GDR nanogel was a self-adjuvanted vaccine carrier that not only promoted DC maturation through activating retinoic acid receptor (RAR) signaling, but also facilitated antigen uptake and cytosolic antigen release in DCs. Furthermore, pH-sensitive GDR nanogel effectively augmented MHC I antigen presentation and evoked potent anti-cancer immune responses in vivo. More importantly, we first reported that nanoparticle-triggered lysosome rupture could directly induce ROS production in DCs, which was found to be essential for augmenting proteasome activity and downstream MHC I antigen presentation. Hence, DC-targeted pH-sensitive GDR nanogels could be a potent delivery system for cancer vaccine development. Triggering lyososomal rupture in DCs with pH-sensitive nanoparticles might be a plausible strategy to elevate intracellular ROS production for promoting antigen cross presentation, thereby improving cancer vaccine efficacy.

  10. Interleukin 10 (IL-10)-mediated Immunosuppression: MARCH-I INDUCTION REGULATES ANTIGEN PRESENTATION BY MACROPHAGES BUT NOT DENDRITIC CELLS.

    PubMed

    Mittal, Sharad K; Cho, Kyung-Jin; Ishido, Satoshi; Roche, Paul A

    2015-11-06

    Efficient immune responses require regulated antigen presentation to CD4 T cells. IL-10 inhibits the ability of dendritic cells (DCs) and macrophages to stimulate antigen-specific CD4 T cells; however, the mechanisms by which IL-10 suppresses antigen presentation remain poorly understood. We now report that IL-10 stimulates expression of the E3 ubiquitin ligase March-I in activated macrophages, thereby down-regulating MHC-II, CD86, and antigen presentation to CD4 T cells. By contrast, IL-10 does not stimulate March-I expression in DCs, does not suppress MHC-II or CD86 expression on either resting or activated DCs, and does not affect antigen presentation by activated DCs. IL-10 does, however, inhibit the process of DC activation itself, thereby reducing the efficiency of antigen presentation in a March-I-independent manner. Thus, IL-10 suppression of antigen presenting cell function in macrophages is March-I-dependent, whereas in DCs, suppression is March- I-independent. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Antigen Presented by Tumors in Vivo Determines the Nature of CD8+ T Cell Cytotoxicity

    PubMed Central

    Shanker, Anil; Brooks, Alan D.; Jacobsen, Kristen M.; Wine, John W.; Wiltrout, Robert H.; Yagita, Hideo; Sayers, Thomas J.

    2009-01-01

    The biological relevance of the perforin and Fas ligand (FasL) cytolytic pathways of CD8+ T lymphocytes (CTL) for cancer immunotherapy is controversial. We investigated the importance of these pathways in a murine renal cell carcinoma expressing influenza viral hemagglutinin as a defined surrogate antigen (Renca-HA). Following Renca-HA injection, all FasL-dysfunctional FasLgld/gld mice (n = 54) died from Renca-HA tumors by day 62. By contrast, perforin−/− (51%, n = 45) and Faslpr/lpr (55%, n = 51) mice remained tumor-free at day 360. Blocking FasL in vivo inhibited tumor rejection in these mice. Moreover, established Renca-HA tumors were cleared more efficiently by adoptively transferred HA518–526-specific T cell receptor-transgenic CTL utilizing FasL rather than perforin. Strikingly, a range of mouse tumor cells presenting low concentrations of immunogenic peptide were all preferentially lysed by the FasL but not the Pfp-mediated effector pathway of CTL, whereas at higher peptide concentrations the preference in effector pathway usage by CTL was lost. Interestingly, a number of human renal cancer lines were also susceptible to FasL-mediated cytotoxicity. Therefore, the FasL cytolytic pathway may be particularly important for eradicating Fas-sensitive tumors presenting low levels of MHC class-I-associated antigens following adoptive T cell therapy. PMID:19654302

  12. Human γδ T Cells Augment Antigen Presentation in Listeria Monocytogenes Infection

    PubMed Central

    Zhu, Yuli; Wang, Huaishan; Xu, Yi; Hu, Yu; Chen, Hui; Cui, Lianxian; Zhang, Jianmin; He, Wei

    2016-01-01

    Circulating γδ T cells in healthy individuals rapidly respond to bacterial and viral pathogens. Many studies have demonstrated that γδ T cells are activated and expanded by Listeria monocytogenes (L. monocytogenes), a foodborne bacterial pathogen with high fatality rates. However, the roles of γδ T cells during L. monocytogenes infection are not clear. In the present study, we characterized the morphological characteristics of phagocytosis in γδ T cells after L. monocytogenes infection using transmission electron microscopy. Results show activation markers including human leucocyte antigen DR (HLA–DR) and lymph node–homing receptor CCR7 on γδ T cells were upregulated after stimulation via L. monocytogenes. Significant proliferation and differentiation of primary αβ T cells was also observed after coculture of peripheral blood mononuclear cells with γδ T cells anteriorly stimulated by L. monocytogenes. L. monocytogenes infection decreased the percentage of γδ T cells in mouse intraepithelial lymphocytes (IELs) and increased MHC-II expression on the surface of γδ T cells in vivo. Our findings shed light on antigen presentation of γδ T cells during L. monocytogenes infection. PMID:27652377

  13. Interview: glycolipid antigen presentation by CD1d and the therapeutic potential of NKT cell activation.

    PubMed

    Kronenberg, Mitchell

    2007-01-01

    Natural Killer T cells (NKT) are critical determinants of the immune response to cancer, regulation of autioimmune disease, clearance of infectious agents, and the development of artheriosclerotic plaques. In this interview, Mitch Kronenberg discusses his laboratory's efforts to understand the mechanism through which NKT cells are activated by glycolipid antigens. Central to these studies is CD1d--the antigen presenting molecule that presents glycolipids to NKT cells. The advent of CD1d tetramer technology, a technique developed by the Kronenberg lab, is critical for the sorting and identification of subsets of specific glycolipid-reactive T cells. Mitch explains how glycolipid agonists are being used as therapeutic agents to activate NKT cells in cancer patients and how CD1d tetramers can be used to assess the state of the NKT cell population in vivo following glycolipid agonist therapy. Current status of ongoing clinical trials using these agonists are discussed as well as Mitch's prediction for areas in the field of immunology that will have emerging importance in the near future.

  14. Oxidation matters: the ubiquitin proteasome system connects innate immune mechanisms with MHC class I antigen presentation.

    PubMed

    Warnatsch, Annika; Bergann, Theresa; Krüger, Elke

    2013-09-01

    During innate immune responses the delicate balance of protein synthesis, quality control and degradation is severely challenged by production of radicals and/or the massive synthesis of pathogen proteins. The regulated degradation of ubiquitin-tagged proteins by the ubiquitin proteasome system (UPS) represents one major pathway for the maintenance of cellular proteostasis and regulatory processes under these conditions. In addition, MHC class I antigen presentation is strictly dependent on an appropriate peptide supply by the UPS to efficiently prime CD8(+) T cells and to initiate an adaptive immune response. We here discuss recent efforts in defining the link between innate immune mechanisms like cytokine and ROS production, the induction of an efficient adaptive immune response and the specific involvement of the UPS therein. Cytokines and/or infections induce translation and the production of free radicals, which in turn confer oxidative damage to nascent as well as folded proteins. In parallel, the same signaling cascades are able to accelerate the protein turnover by the concomitantly induced ubiquitin conjugation and degradation of such damaged polypeptides by immunoproteasomes. The ability of immunoproteasomes to efficiently degrade such oxidant-damaged ubiquitylated proteins protects cells from accumulating toxic ubiquitin-rich aggregates. At the same time, this innate immune mechanism facilitates a sufficient peptide supply for MHC class I antigen presentation and connects it to initiation of adaptive immunity.

  15. Gatekeeper role of brain antigen-presenting CD11c+ cells in neuroinflammation.

    PubMed

    Paterka, Magdalena; Siffrin, Volker; Voss, Jan O; Werr, Johannes; Hoppmann, Nicola; Gollan, René; Belikan, Patrick; Bruttger, Julia; Birkenstock, Jérôme; Jung, Steffen; Esplugues, Enric; Yogev, Nir; Flavell, Richard A; Bopp, Tobias; Zipp, Frauke

    2016-01-04

    Multiple sclerosis is the most frequent chronic inflammatory disease of the CNS. The entry and survival of pathogenic T cells in the CNS are crucial for the initiation and persistence of autoimmune neuroinflammation. In this respect, contradictory evidence exists on the role of the most potent type of antigen-presenting cells, dendritic cells. Applying intravital two-photon microscopy, we demonstrate the gatekeeper function of CNS professional antigen-presenting CD11c(+) cells, which preferentially interact with Th17 cells. IL-17 expression correlates with expression of GM-CSF by T cells and with accumulation of CNS CD11c(+) cells. These CD11c(+) cells are organized in perivascular clusters, targeted by T cells, and strongly express the inflammatory chemokines Ccl5, Cxcl9, and Cxcl10. Our findings demonstrate a fundamental role of CNS CD11c(+) cells in the attraction of pathogenic T cells into and their survival within the CNS. Depletion of CD11c(+) cells markedly reduced disease severity due to impaired enrichment of pathogenic T cells within the CNS. © 2015 The Authors.

  16. HAM56 and CD68 antigen presenting cells surrounding a sarcoidal granulomatous tattoo

    PubMed Central

    Velez, Ana Maria Abreu; DeJoseph, Louis M.; Howard, Michael S.

    2011-01-01

    Context Tattoos are produced by introducing colorants of various compositions into the skin, either accidentally or for cosmetic purposes. Case Report: A 62-year-old male presented with a cosmetic tattoo and requested a total excision of the lesion. Dermatopathologic analysis of the excised tissue with hematoxylin and eosin examination, as well as immunohistochemistry was performed. H&E staining demonstrated classic histologic features of a tattoo. Utilizing immunohistochemistry, dermal histiocytic antigen presenting cells stained with HAM56 and CD68 antibodies; the staining was present surrounding the tattoo pigment. Conclusions We identified two macrophage markers (HAM56 and CD68) surrounding dermal tattoo pigment. A minimal dermal inflammatory immune was noted to the tattoo pigment. Moreover, the immune response and/or tolerance to tattoos is not well characterized. We suggest that tattoo materials and techniques could be utilized in therapeutic delivery for diseases such recessive dystrophic epidermolysis bullosa, potentially preventing immune rejection of gene therapy agents. PMID:22363088

  17. Systemic activation of antigen-presenting cells via RNA-loaded nanoparticles

    PubMed Central

    Sayour, Elias J.; Pham, Christina; Grippin, Adam; Kemeny, Hanna; Chua, Joshua; Sampson, John H.; Sanchez-Perez, Luis; Flores, Catherine; Mitchell, Duane A.

    2017-01-01

    ABSTRACT While RNA-pulsed dendritic cell (DC) vaccines have shown promise, the advancement of cellular therapeutics is fraught with developmental challenges. To circumvent the challenges of cellular immunotherapeutics, we developed clinically translatable nanoliposomes that can be combined with tumor-derived RNA to generate personalized tumor RNA-nanoparticles (NPs) with considerable scale-up capacity. RNA-NPs bypass MHC restriction, are amenable to central distribution, and can provide near immediate immune induction. We screened commercially available nanoliposomal preparations and identified the cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) as an efficient mRNA courier to antigen-presenting cells (APCs). When administered intravenously, RNA-NPs mediate systemic activation of APCs in reticuloendothelial organs such as the spleen, liver, and bone marrow. RNA-NPs increase percent expression of MHC class I/II, B7 co-stimulatory molecules, and maturation markers on APCs (all vital for T-cell activation). RNA-NPs also increase activation markers on tumor APCs and elicit potent expansion of antigen-specific T-cells superior to peptide vaccines formulated in complete Freund's adjuvant. We demonstrate that both model antigen-encoding and physiologically-relevant tumor-derived RNA-NPs expand potent antitumor T-cell immunity. RNA-NPs were shown to induce antitumor efficacy in a vaccine model and functioned as a suitable alternative to DCs in a stringent cellular immunotherapy model for a radiation/temozolomide resistant invasive murine high-grade glioma. Although cancer vaccines have suffered from weak immunogenicity, we have advanced a RNA-NP formulation that systemically activates host APCs precipitating activated T-cell frequencies necessary to engender antitumor efficacy. RNA-NPs can thus be harnessed as a more feasible and effective immunotherapy to re-program host-immunity. PMID:28197373

  18. A strategy of antigen incorporation into exosomes: comparing cross-presentation levels of antigens delivered by engineered exosomes and by lentiviral virus-like particles.

    PubMed

    Lattanzi, Laura; Federico, Maurizio

    2012-11-26

    Among strategies aimed at developing new nanoparticle-based vaccines, exosomes hold much promise. They are nanovesicles released by basically all eukaryotic cell types originating from intraluminal vesicles which accumulate in multivesicular bodies. Exosomes have immunogenic properties whose strength correlates with the amounts of associated antigens. Engineering antigens to target them in exosomes represents the last frontier in terms of nanoparticle-based vaccines. Here we report a new method to incorporate protein antigens in exosomes relying on the unique properties of a mutant of the HIV-1 Nef protein, Nef(mut). This is a biologically inactive mutant we found incorporating into exosomes at high levels also when fused at its C-terminus with foreign proteins. We compared both biochemical and antigenic properties of Nef(mut) exosomes with those of previously characterized Nef(mut) -based lentiviral virus-like particles (VLPs). We found that exosomes incorporate Nef(mut) and fusion protein derivatives with similar efficiency of VLPs. When an envelope fusion protein was associated with both exosomes and VLPs to favor cross-presentation of associated antigens, Nef(mut) and its derivatives incorporated in exosomes were cross-presented at levels at least similar to what observed when the antigens were delivered by engineered VLPs. This occurred despite exosomes entered target cells with an apparent lower efficiency than VLPs. The unique properties of HIV-1 Nef(mut) in terms of exosome incorporation efficiency, carrier of foreign antigens, and lack of anti-cellular effects open the way toward the development of a flexible, safe, cost-effective exosome-based CD8(+) T cell vaccine platform.

  19. P2X7 Receptor Activation Impairs Exogenous MHC Class I Oligopeptides Presentation in Antigen Presenting Cells

    PubMed Central

    Baroja-Mazo, Alberto; Barberà-Cremades, Maria; Pelegrín, Pablo

    2013-01-01

    Major histocompatibility complex class I (MHC I) on antigen presenting cells (APCs) is a potent molecule to activate CD8+ T cells and initiate immunity. P2X7 receptors (P2X7Rs) are present on the plasma membrane of APCs to sense the extracellular danger signal adenosine-5′-triphosphate (ATP). P2X7R activates the inflammasome and the release of IL-1β in macrophages and other immune cells to initiate the inflammatory response. Here we show that P2X7R stimulation by ATP in APCs decreased the amount of MHC I at the plasma membrane. Specific antagonism or genetic ablation of P2X7R inhibited the effects of ATP on levels of cellular MHC I. Furthermore, P2X7R stimulation was able to inhibit activation of CD8+ T cells via specific MHC I-oligopeptide complexes. Our study suggests that P2X7R activation on APCs is a novel inhibitor of adaptive CD8+ T cell immunity. PMID:23940597

  20. Genetic modulation of antigen presentation by HLA-B27 molecules

    PubMed Central

    1992-01-01

    In studies of antigenic peptide presentation, we have found a healthy volunteer whose lymphoblastoid cells were unable to present three different virus-derived epitopes to cytotoxic T lymphocytes (CTL) despite expressing the correct restricting HLA-B27 molecules on the cell surface. B cell lines were established from other members of the donor's family, including individuals suffering from ankylosing spondylitis and related diseases, and were tested for their ability to function as target cells in the same assay. None of the eight B cell lines that expressed HLA-B27 presented a known peptide epitope to CTL. However, cells from a family member that expressed HLA-B8 could present an epitope peptide restricted by that molecule. The B27 molecule in this family proved to be the B2702 subtype on isoelectric focusing gels, appearing in exactly the same position as B2702 from other cell lines that did present the peptide. To exclude mutations resulting in noncharged amino acid substitutions, cDNA coding for B2702 was cloned from the proband's cell line and sequenced. No coding changes were found. The cloned cDNA was transfected into HLA-A- and B-negative HMy/C1R cells, and the B2702 molecules generated in this environment rendered these cells, after incubation with peptide, susceptible to lysis by peptide-specific CTL. These data are compatible with the presence of a factor(s), possibly HLA linked, interfering with antigen presentation by otherwise normal B2702 molecules in this family. PMID:1370680

  1. Mosaic HIV-1 Gag antigens can be Processed and Presented to human HIV-specific CD8+ T cells

    PubMed Central

    Ndhlovu, Zaza M; Piechocka-Trocha, Alicja; Vine, Seanna; McMullen, Ashley; Koofhethile, Kegakilwe C; Goulder, Phillip JR; Ndung’u, Thumbi; Barouch, Dan H; Walker, Bruce D

    2011-01-01

    Polyvalent “mosaic” HIV immunogens offer a potential solution for generating vaccines that can elicit immune responses against genetically diverse viruses. However, it is unclear whether key T cell epitopes can be processed and presented from these synthetic antigens and recognized by epitope-specific human T cells. Here we tested the ability of mosaic HIV immunogens expressed by recombinant, replication-incompetent adenovirus serotype 26 vectors to process and present major HIV clade B and clade C CD8 T cell epitopes in human cells. A bivalent mosaic vaccine expressing HIV Gag sequences was used to transduce PBMC from 12 HIV-1-infected individuals from the US and 10 HIV-1-infected individuals from South Africa, and intracellular cytokine staining together with tetramer staining was used to assess the ability of mosaic Gag antigens to stimulate pre-existing memory responses compared to natural clade B and C vectors. Mosaic Gag antigens expressed all 8 clade B epitopes tested in 12 US subjects and all 5 clade C epitopes tested in 10 South African subjects. Overall, the magnitude of cytokine production induced by stimulation with mosaic antigens was comparable to clade B and clade C antigens tested, but the mosaic antigens elicited greater cross-clade recognition. Additionally, mosaic antigens also induced HIV-specific CD4 T cell responses. Our studies demonstrate that mosaic antigens express major clade B and clade C viral T cell epitopes in human cells, and support the evaluation of mosaic HIV-1 vaccines in humans. PMID:21576505

  2. Hematopoietic stem cell recipients do not develop post-transplantation immune tolerance to antigens present on minimal residual disease.

    PubMed

    Natzke, Amanda Martinelli; Shaw, Joanne L; McKeller, Morgan R; Emo, Kris Lambert; Mullen, Craig A

    2007-01-01

    The immune environment present after allogeneic hematopoietic stem cell transplantation (HSCT) contributes to the control of leukemia. Our laboratory has demonstrated in a murine model that vaccination of recipients after transplantation with recipient tumor vaccines does not exacerbate graft-versus-host disease but does induce meaningful graft-versus-tumor effects. We previously demonstrated that part of the reason for the lack of graft-versus-host disease from post-transplantation vaccination is due to gradual acquisition of tolerance or unresponsiveness to recipient immunodominant minor histocompatibility antigens that are ubiquitously expressed in the recipient. However, our prior studies have not critically addressed the question of whether a similar process of acquisition of unresponsiveness to or tolerance of antigens present on minimal residual disease also occurs. The present study tested the hypothesis that unresponsiveness to antigens present on minimal residual disease present at the time of HSCT would also occur. The answer to this question would have a significant effect on the potential efficacy of post-transplantation tumor vaccines. In a murine model of major histocompatibility complex matched, minor histocompatibility antigen mismatched HSCT (C3.SW female donors and C57BL/6 female recipients), we tested whether transplant recipients would acquire unresponsiveness to antigens present on small numbers of residual leukemia/lymphoma cells. We employed a male C57BL/6 lymphoid malignancy with an immunoglobulin/c-myc oncogene in these studies using as a model of tumor-restricted antigen the well-characterized male (HY) antigen system present only on the tumor but not present as ubiquitous minor antigens in the recipient. After HSCT, recipients did not mount immune responses to the ubiquitously distributed immunodominant recipient strain H7 minor histocompatibility antigen, but did retain the capacity to mount significant T cell responses to HY antigens

  3. Enhanced antigen-presenting capacity of cultured Langerhans' cells is associated with markedly increased expression of Ia antigen

    SciTech Connect

    Shimada, S.; Caughman, S.W.; Sharrow, S.O.; Stephany, D.; Katz, S.I.

    1987-10-15

    Recent studies indicate that when epidermal Langerhans' cells (LC) are cultured for 2 to 3 days they, in comparison to freshly prepared LC, exhibit markedly enhanced ability to stimulate T cell proliferative responses in oxidative mitogenesis and in the mixed epidermal-leukocyte reaction. In this study, we determined whether cultured LC enhance antigen-specific T cell responses, and whether such enhanced stimulatory capacity correlates with the level of Ia antigen expressed on LC. We used C3H/He (Iak) epidermal cells as stimulators and, as responder cells, both the trinitrophenyl-specific clones D8 and SE4, which were assayed for (/sup 3/H)dThd incorporation, and the pigeon cytochrome c specific hybridoma 2C2, which was assayed for interleukin 2 production. Cultured LC induced 10 to 100 times greater proliferation or interleukin 2 production by responder cells than did freshly prepared LC. The intensity of I-Ak and I-Ek, expressed on cultured LC as assessed by immunofluorescence and flow cytometry, was found to be 10 to 36 times greater on a per cell basis than that on freshly prepared LC. Depletion of LC from fresh epidermal cell suspensions by anti-Iak and complement or treatment with 50 mJ/cm/sup 2/ medium range ultraviolet light or cycloheximide before culture abrogated both the increase in Ia expression and antigen-specific clonal proliferation. The results suggest that when LC are removed from their usual epidermal milieu, they express increased amounts of Ia and become more potent stimulators of T cell responses.

  4. Major Histocompatibility Complex (MHC) Class I and MHC Class II Proteins: Conformational Plasticity in Antigen Presentation

    PubMed Central

    Wieczorek, Marek; Abualrous, Esam T.; Sticht, Jana; Álvaro-Benito, Miguel; Stolzenberg, Sebastian; Noé, Frank; Freund, Christian

    2017-01-01

    Antigen presentation by major histocompatibility complex (MHC) proteins is essential for adaptive immunity. Prior to presentation, peptides need to be generated from proteins that are either produced by the cell’s own translational machinery or that are funneled into the endo-lysosomal vesicular system. The prolonged interaction between a T cell receptor and specific pMHC complexes, after an extensive search process in secondary lymphatic organs, eventually triggers T cells to proliferate and to mount a specific cellular immune response. Once processed, the peptide repertoire presented by MHC proteins largely depends on structural features of the binding groove of each particular MHC allelic variant. Additionally, two peptide editors—tapasin for class I and HLA-DM for class II—contribute to the shaping of the presented peptidome by favoring the binding of high-affinity antigens. Although there is a vast amount of biochemical and structural information, the mechanism of the catalyzed peptide exchange for MHC class I and class II proteins still remains controversial, and it is not well understood why certain MHC allelic variants are more susceptible to peptide editing than others. Recent studies predict a high impact of protein intermediate states on MHC allele-specific peptide presentation, which implies a profound influence of MHC dynamics on the phenomenon of immunodominance and the development of autoimmune diseases. Here, we review the recent literature that describe MHC class I and II dynamics from a theoretical and experimental point of view and we highlight the similarities between MHC class I and class II dynamics despite the distinct functions they fulfill in adaptive immunity. PMID:28367149

  5. Cowpox virus employs a two-pronged strategy to outflank MHCI antigen presentation.

    PubMed

    McCoy, William H; Wang, Xiaoli; Yokoyama, Wayne M; Hansen, Ted H; Fremont, Daved H

    2013-09-01

    Smallpox decimated humanity for thousands of years before being eradicated by vaccination, a success facilitated by the fact that humans are the only host of variola virus. In contrast, other orthopoxviruses such as cowpox virus can infect a variety of mammalian species, although its dominant reservoir appears to be rodents. This difference in host specificity suggests that cowpox may have developed promiscuous immune evasion strategies to facilitate zoonosis. Recent experiments have established that cowpox can disrupt MHCI antigen presentation during viral infection of both human and murine cells, a process enabled by two unique proteins, CPXV012 and CPXV203. While CPXV012 inhibits antigenic peptide transport from the cytosol to the ER, CPXV203 blocks MHCI trafficking to the cell surface by exploiting the KDEL-receptor recycling pathway. Our recent investigations of CPXV203 reveal that it binds a diverse array of classical and non-classical MHCI proteins with dramatically increased affinities at the lower pH of the Golgi relative to the ER, thereby providing mechanistic insight into how it works synergistically with KDEL receptors to block MHCI surface expression. The strategy used by cowpox to both limit peptide supply and disrupt trafficking of fully assembled MHCI acts as a dual-edged sword that effectively disables adaptive immune surveillance of infected cells.

  6. B7 expression and antigen presentation by human brain endothelial cells: requirement for proinflammatory cytokines.

    PubMed

    Prat, A; Biernacki, K; Becher, B; Antel, J P

    2000-02-01

    Interaction between systemic immune cells with cells of the blood-brain barrier is a central step in development of CNS-directed immune responses. Endothelial cells are the first cells of the blood-brain barrier encountered by migrating lymphocytes. To investigate the antigen-presenting capacity of human adult brain endothelial cells (HBECs), we used HBECs derived from surgically resected temporal lobe tissue, cocultured with allogeneic peripheral blood derived CD4+ T lymphocytes. HBECs in response to IFN-gamma, but not under basal culture conditions, expressed HLA-DR, B7.1 and B7.2 antigens. Despite such up-regulation, these IFN-gamma-treated HBECs, in contrast to human microglia and PB monocytes, did not sustain allogeneic CD4+ cell proliferation, supported only low levels of IL-2 and IFN-gamma production, and did not stimulate IL-2 receptor expression. CD4+ T cell proliferation and increased IL-2 receptor expression could be obtained by addition of IL-2. Our data suggests that, although HBECs cannot alone support T cell proliferation and cytokine production, HBECs acting in concert with cytokines derived from a proinflammatory environment could support such a response.

  7. HLA-DO as the Optimizer of Epitope Selection for MHC Class II Antigen Presentation

    PubMed Central

    Poluektov, Yuri O.; Kim, AeRyon; Hartman, Isamu Z.; Sadegh-Nasseri, Scheherazade

    2013-01-01

    Processing of antigens for presentation to helper T cells by MHC class II involves HLA-DM (DM) and HLA-DO (DO) accessory molecules. A mechanistic understanding of DO in this process has been missing. The leading model on its function proposes that DO inhibits the effects of DM. To directly study DO functions, we designed a recombinant soluble DO and expressed it in insect cells. The kinetics of binding and dissociation of several peptides to HLA-DR1 (DR1) molecules in the presence of DM and DO were measured. We found that DO reduced binding of DR1 to some peptides, and enhanced the binding of some other peptides to DR1. Interestingly, these enhancing and reducing effects were observed in the presence, or absence, of DM. We found that peptides that were negatively affected by DO were DM-sensitive, whereas peptides that were enhanced by DO were DM-resistant. The positive and negative effects of DO could only be measured on binding kinetics as peptide dissociation kinetics were not affected by DO. Using Surface Plasmon Resonance, we demonstrate direct binding of DO to a peptide-receptive, but not a closed conformation of DR1. We propose that DO imposes another layer of control on epitope selection during antigen processing. PMID:23951115

  8. A fusion DNA vaccine that targets antigen-presenting cells increases protection from viral challenge

    NASA Astrophysics Data System (ADS)

    Deliyannis, Georgia; Boyle, Jefferey S.; Brady, Jamie L.; Brown, Lorena E.; Lew, Andrew M.

    2000-06-01

    Improving the immunological potency, particularly the Ab response, is a serious hurdle for the protective efficacy and hence broad application of DNA vaccines. We examined the immunogenicity and protective efficacy of a hemagglutinin-based influenza DNA vaccine that was targeted to antigen-presenting cells (APCs) by fusion to CTLA4. The targeted vaccine was shown to induce an accelerated and increased Ab response (as compared with those receiving the nontargeted control) that was predominated by IgG1 and recognized conformationally dependent viral epitopes. Moreover, mice receiving the APC-targeted DNA vaccine had significantly reduced viral titers (100-fold) after a nonlethal virus challenge. The increased protective efficacy was most likely because of increased Ab responses, as cytotoxic T lymphocyte responses were not enhanced. Targeting was demonstrated by direct binding studies of CTLA4 fusion proteins to the cognate ligand (B7; expressed on APCs in vivo). In addition, a targeted protein was detected at 4-fold higher levels in draining lymph nodes within 2-24 h of administration. Therefore, this study demonstrates that targeting DNA-encoded antigen to APCs results in enhanced immunity and strongly suggests that this approach may be useful in improving the protective efficacy of DNA vaccines.

  9. Immunology by numbers: quantitation of antigen presentation completes the quantitative milieu of systems immunology!

    PubMed

    Purcell, Anthony W; Croft, Nathan P; Tscharke, David C

    2016-06-01

    We review approaches to quantitate antigen presentation using a variety of biological and biochemical readouts and highlight the emerging role of mass spectrometry (MS) in defining and quantifying MHC-bound peptides presented at the cell surface. The combination of high mass accuracy in the determination of the molecular weight of the intact peptide of interest and its signature pattern of fragmentation during tandem MS provide an unambiguous and definitive identification. This is in contrast to the potential receptor cross-reactivity towards closely related peptides and variable dose responsiveness seen in biological readouts. In addition, we gaze into the not too distant future where big data approaches in MS can be accommodated to quantify whole immunopeptidomes both in vitro and in vivo.

  10. Mechanism of Action of Probiotic Bacteria on Intestinal and Systemic Immunities and Antigen-Presenting Cells.

    PubMed

    Fong, Fiona Long Yan; Shah, Nagendra P; Kirjavainen, Pirkka; El-Nezami, Hani

    2016-05-03

    Immunomodulation has been shown to be one of the major functions of probiotic bacteria. This review is presented to provide detailed information on the immunomodulatory properties of probiotics in various animal models and clinical practices. Probiotics can regulate helper T (Th) responses and release of cytokines in a strain-specific manner. For example, Lactobacillus rhamnosus GG can induce beneficial Th1 immunomodulatory effect in infants with cow's milk allergy and relieve intestinal inflammation in atopic children by promoting IL-10 generation. Mechanism of action of probiotics on antigen-presenting cells at gastrointestinal tract is also postulated in this review. Probiotic bacterial cells and their soluble factors may activate dendritic cells, macrophages, and to certain extent monocytes via toll-like-receptor recognition and may further provoke specific Th responses. They are speculated to elicit immunomodulatory effects on intestinal and systemic immunities.

  11. Antigen-presenting dendritic cells rescue CD4-depleted CCR2-/- mice from lethal Histoplasma capsulatum infection.

    PubMed

    Szymczak, Wendy A; Deepe, George S

    2010-05-01

    Excessive production of interleukin-4 impairs clearance of the fungal pathogen Histoplasma capsulatum in mice lacking the chemokine receptor CCR2. An increase in the interleukin-4 level is associated with decreased recruitment of dendritic cells to lungs; therefore, we investigated the possibility that these cells influence interleukin-4 production. Adoptive transfer of wild-type or CCR2(-/-) bone marrow-derived dendritic cells loaded with heat-killed yeast cells to infected CCR2(-/-) mice suppressed interleukin-4 transcription. Surprisingly, transfer of cells did not reduce the fungal burden despite the fact that it limited interleukin-4 transcription. Yeast cell-loaded bone marrow-derived dendritic cell-mediated regulation of interleukin-4 transcription was dependent on major histocompatibility complex II antigen presentation to CD4(+) T cells. We previously showed that CD4(+) T cells were a source of interleukin-4 in infected CCR2(-/-) mice, but their contribution to the TH2 phenotype was unclear. Here we demonstrated that these cells were functionally important since elimination of them prior to infection, but not elimination of them at the time of infection, reduced the interleukin-4 level in infected CCR2(-/-) mice. However, the fungal burden was reduced only in CD4-depleted CCR2(-/-) mice that received yeast cell-loaded bone marrow-derived dendritic cells. Taken together, the data indicate that generation of excess interleukin-4 in lungs of H. capsulatum-infected CCR2(-/-) mice is at least partially a consequence of decreased recruitment of dendritic cells capable of antigen presentation. Furthermore, CD4(+) T cells had a deleterious impact on immunity in infected CCR2(-/-) mice.

  12. Antigen-Presenting Dendritic Cells Rescue CD4-Depleted CCR2−/− Mice from Lethal Histoplasma capsulatum Infection▿

    PubMed Central

    Szymczak, Wendy A.; Deepe, George S.

    2010-01-01

    Excessive production of interleukin-4 impairs clearance of the fungal pathogen Histoplasma capsulatum in mice lacking the chemokine receptor CCR2. An increase in the interleukin-4 level is associated with decreased recruitment of dendritic cells to lungs; therefore, we investigated the possibility that these cells influence interleukin-4 production. Adoptive transfer of wild-type or CCR2−/− bone marrow-derived dendritic cells loaded with heat-killed yeast cells to infected CCR2−/− mice suppressed interkeukin-4 transcription. Surprisingly, transfer of cells did not reduce the fungal burden despite the fact that it limited interleukin-4 transcription. Yeast cell-loaded bone marrow-derived dendritic cell-mediated regulation of interleukin-4 transcription was dependent on major histocompatibility complex II antigen presentation to CD4+ T cells. We previously showed that CD4+ T cells were a source of interleukin-4 in infected CCR2−/− mice, but their contribution to the TH2 phenotype was unclear. Here we demonstrated that these cells were functionally important since elimination of them prior to infection, but not elimination of them at the time of infection, reduced the interleukin-4 level in infected CCR2−/− mice. However, the fungal burden was reduced only in CD4-depleted CCR2−/− mice that received yeast cell-loaded bone marrow-derived dendritic cells. Taken together, the data indicate that generation of excess interleukin-4 in lungs of H. capsulatum-infected CCR2−/− mice is at least partially a consequence of decreased recruitment of dendritic cells capable of antigen presentation. Furthermore, CD4+ T cells had a deleterious impact on immunity in infected CCR2−/− mice. PMID:20194586

  13. Processing of some antigens by the standard proteasome but not by the immunoproteasome results in poor presentation by dendritic cells.

    PubMed

    Morel, S; Lévy, F; Burlet-Schiltz, O; Brasseur, F; Probst-Kepper, M; Peitrequin, A L; Monsarrat, B; Van Velthoven, R; Cerottini, J C; Boon, T; Gairin, J E; Van den Eynde, B J

    2000-01-01

    By stimulating human lymphocytes with an autologous renal carcinoma, we obtained CTL recognizing an antigen derived from a novel, ubiquitous protein. The CTL failed to lyse autologous EBV-transformed B cells, even though the latter express the protein. This is due to the presence in these cells of immunoproteasomes, which, unlike standard proteasomes, cannot produce the antigenic peptide. We show that dendritic cells also carry immunoproteasomes and fail to present this antigen. This may explain why the relevant CTL escape thymic deletion and are not regularly activated in the periphery. Lack of cleavage by the immunoproteasome was also observed for melanoma differentiation antigen Melan-A26-35/HLA-A2, currently used for antitumoral vaccination. For immunization with such antigens, proteins should be less suitable than peptides, which do not require proteasome digestion in dendritic cells.

  14. Cross-presentation through langerin and DC-SIGN targeting requires different formulations of glycan-modified antigens.

    PubMed

    Fehres, Cynthia M; Kalay, Hakan; Bruijns, Sven C M; Musaafir, Sara A M; Ambrosini, Martino; van Bloois, Louis; van Vliet, Sandra J; Storm, Gert; Garcia-Vallejo, Juan J; van Kooyk, Yvette

    2015-04-10

    Dendritic cells (DCs) and Langerhans cells (LC) are professional antigen presenting cells (APCs) that initiate humoral and cellular immune responses. Targeted delivery of antigen towards DC- or LC-specific receptors enhances vaccine efficacy. In this study, we compared the efficiency of glycan-based antigen targeting to both the human DC-specific C-type lectin receptor (CLR) DC-SIGN and the LC-specific CLR langerin. Since DC-SIGN and langerin are able to recognize the difucosylated oligosaccharide Lewis Y (Le(Y)), we prepared neoglycoconjugates bearing this glycan epitope to allow targeting of both lectins. Le(Y)-modified liposomes, with an approximate diameter of 200nm, were significantly endocytosed by DC-SIGN(+) DCs and mediated efficient antigen presentation to CD4(+) and CD8(+) T cells. Surprisingly, although langerin bound to Le(Y)-modified liposomes, LCs exposed to Le(Y)-modified liposomes could not endocytose liposomes nor mediate antigen presentation to T cells. However, LCs mediated an enhanced cross-presentation when antigen was delivered through langerin using Le(Y)-modified synthetic long peptides. In contrast, Le(Y)-modified synthetic long peptides were recognized by DC-SIGN, but did not trigger antigen internalization nor antigen cross-presentation. These data demonstrate that langerin and DC-SIGN have different size requirements for antigen uptake. Although using glycans remains an interesting option in the design of anti-cancer vaccines targeting multiple CLRs, aspects such as molecule size and conformation need to be taken in consideration. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Differential capacity of chaperone-rich lysates in cross-presenting human endogenous and exogenous melanoma differentiation antigens.

    PubMed

    Bleifuss, Elke; Bendz, Henriette; Sirch, Birgit; Thompson, Sylvia; Brandl, Anna; Milani, Valeria; Graner, Michael W; Drexler, Ingo; Kuppner, Maria; Katsanis, Emmanuel; Noessner, Elfriede; Issels, Rolf-Dieter

    2008-12-01

    The goal of immune-based tumor therapies is the activation of immune cells reactive against a broad spectrum of tumor-expressed antigens. Vaccines based on chaperone proteins appear promising as these proteins naturally exist as complexes with various protein fragments including those derived from tumor-associated antigens. Multi-chaperone systems are expected to have highest polyvalency as different chaperones can carry distinct sets of antigenic fragments. A free-solution isoelectric focusing (FS-IEF) technique was established to generate chaperone-rich cell lysates (CRCL). Results from murine systems support the contention that CRCL induce superior anti-tumor responses than single chaperone vaccines. We established an in vitro model for human melanoma to evaluate the capacity of CRCL to transfer endogenously expressed tumor antigens to the cross-presentation pathway of dendritic cells (DC) for antigen-specific T cell stimulation. CRCL prepared from human melanoma lines contained the four major chaperone proteins Hsp/Hsc70, Hsp90, Grp94/gp96 and calreticulin. The chaperones within the melanoma cell-derived CRCL were functionally active in that they enhanced cross-presentation of exogenous peptides mixed into the CRCL preparation. Superior activity was observed for Hsp70-rich CRCL obtained from heat-stressed melanoma cells. Despite the presence of active chaperones, melanoma cell-derived CRCL failed to transfer endogenously expressed melanoma-associated antigens to DC for cross-presentation and cytotoxic T cell (CTL) recognition, even after increasing intracellular protein levels of tumor antigen or chaperones. These findings reveal limitations of the CRCL approach regarding cross-presentation of endogenously expressed melanoma-associated antigens. Yet, CRCL may be utilized as vehicles to enhance the delivery of exogenous antigens for DC-mediated cross-presentation and T cell stimulation.

  16. Retention of empty MHC class I molecules by tapasin is essential to reconstitute antigen presentation in invertebrate cells.

    PubMed Central

    Schoenhals, G J; Krishna, R M; Grandea, A G; Spies, T; Peterson, P A; Yang, Y; Früh, K

    1999-01-01

    Presentation of antigen-derived peptides by major histocompatibility complex (MHC) class I molecules is dependent on an endoplasmic reticulum (ER) resident glycoprotein, tapasin, which mediates their interaction with the transporter associated with antigen processing (TAP). Independently of TAP, tapasin was required for the presentation of peptides targeted to the ER by signal sequences in MHC class I-transfected insect cells. Tapasin increased MHC class I peptide loading by retaining empty but not peptide-containing MHC class I molecules in the ER. Upon co-expression of TAP, this retention/release function of tapasin was sufficient to reconstitute MHC class I antigen presentation in insect cells, thus defining the minimal non-housekeeping functions required for MHC class I antigen presentation. PMID:9927434

  17. RelB nuclear translocation regulates B cell MHC molecule, CD40 expression, and antigen-presenting cell function

    PubMed Central

    O'Sullivan, Brendan J.; MacDonald, Kelli P. A.; Pettit, Allison R.; Thomas, Ranjeny

    2000-01-01

    Mice with targeted RelB mutations demonstrated an essential role for RelB in immune responses and in myeloid dendritic cell differentiation. Human studies suggested a more global transcriptional role in antigen presentation. Burkitt lymphoma cell lines were used as a model to examine the role of RelB in antigen presentation. After transient transfection of BJAB with RelB, strong nuclear expression of RelB-p50 heterodimers was associated with increased APC function and expression of CD40 and MHC class I. Antisense RelB in DG75 reduced antigen-presenting capacity and CD40-mediated up-regulation of MHC molecules. The data indicate that RelB transcriptional activity directly affects antigen presentation and CD40 synthesis. Stimulation of RelB transcriptional activity may provide a positive feedback loop for facilitating productive APC/T cell interactions. PMID:11027342

  18. Herpes simplex virus γ34.5 interferes with autophagosome maturation and antigen presentation in dendritic cells.

    PubMed

    Gobeil, Philipe A M; Leib, David A

    2012-10-16

    The cellular autophagy response induced by herpes simplex virus 1 (HSV-1) is countered by the viral γ34.5 protein. γ34.5 modulates autophagy by binding to the host autophagy protein Beclin-1 and through this binding inhibits the formation of autophagosomes in fibroblasts and neurons. In contrast, in this study dendritic cells (DCs) infected with HSV-1 showed an accumulation of autophagosomes and of the long-lived protein p62. No such accumulations were observed in DCs infected with a γ34.5-null virus or a virus lacking the Beclin-binding domain (BBD) of γ34.5. To explore this further, we established stably transduced DC lines to show that γ34.5 expression alone induced autophagosome accumulation yet prevented p62 degradation. In contrast, DCs expressing a BBD-deleted mutant of γ34.5 were unable to modulate autophagy. DCs expressing γ34.5 were less capable of stimulating T-cell activation and proliferation in response to intracellular antigens, demonstrating an immunological consequence of inhibiting autophagy. Taken together, these data show that in DCs, γ34.5 antagonizes the maturation of autophagosomes and T cell activation in a BBD-dependent manner, illustrating a unique interface between HSV and autophagy in antigen-presenting cells. IMPORTANCE Herpes simplex virus 1 (HSV-1) is a highly prevalent pathogen causing widespread morbidity and some mortality. HSV infections are lifelong, and there are no vaccines or antivirals to cure HSV infections. The ability of HSV to modulate host immunity is critical for its virulence. HSV inhibits host autophagy, a pathway with importance in many areas of health and disease. Autophagy is triggered by many microbes, some of which harness autophagy for replication; others evade autophagy or prevent it from occurring. Autophagy is critical for host defense, either by directly degrading the invading pathogen ("xenophagy") or by facilitating antigen presentation to T cells. In this study, we show that HSV manipulates

  19. Expanded Human Blood-Derived γδT Cells Display Potent Antigen-Presentation Functions

    PubMed Central

    Khan, Mohd Wajid A.; Curbishley, Stuart M.; Chen, Hung-Chang; Thomas, Andrew D.; Pircher, Hanspeter; Mavilio, Domenico; Steven, Neil M.; Eberl, Matthias; Moser, Bernhard

    2014-01-01

    Cell-based immunotherapy strategies target tumors directly (via cytolytic effector cells) or aim at mobilizing endogenous anti-tumor immunity. The latter approach includes dendritic cells (DC) most frequently in the form of in vitro cultured peripheral blood monocytes-derived DC. Human blood γδT cells are selective for a single class of non-peptide agonists (“phosphoantigens”) and develop into potent antigen-presenting cells (APC), termed γδT-APC within 1–3 days of in vitro culture. Availability of large numbers of γδT-APC would be advantageous for use as a novel cellular vaccine. We here report optimal γδT cell expansion (>107 cells/ml blood) when peripheral blood mononuclear cells (PBMC) from healthy individuals and melanoma patients were stimulated with zoledronate and then cultured for 14 days in the presence of IL-2 and IL-15, yielding γδT cell cultures of variable purity (77 ± 21 and 56 ± 26%, respectively). They resembled effector memory αβT (TEM) cells and retained full functionality as assessed by in vitro tumor cell killing as well as secretion of pro-inflammatory cytokines (IFNγ, TNFα) and cell proliferation in response to stimulation with phosphoantigens. Importantly, day 14 γδT cells expressed numerous APC-related cell surface markers and, in agreement, displayed potent in vitro APC functions. Day 14 γδT cells from PBMC of patients with cancer were equally effective as their counterparts derived from blood of healthy individuals and triggered potent CD8+ αβT cell responses following processing and cross-presentation of simple (influenza M1) and complex (tuberculin purified protein derivative) protein antigens. Of note, and in clear contrast to peripheral blood γδT cells, the ability of day 14 γδT cells to trigger antigen-specific αβT cell responses did not depend on re-stimulation. We conclude that day 14 γδT cell cultures provide a convenient source of autologous APC for use in immunotherapy of patients

  20. EpsinR, a target for pyrenocine B, role in endogenous MHC-II-restricted antigen presentation.

    PubMed

    Shishido, Tatsuya; Hachisuka, Masami; Ryuzaki, Kai; Miura, Yuko; Tanabe, Atsushi; Tamura, Yasuaki; Kusayanagi, Tomoe; Takeuchi, Toshifumi; Kamisuki, Shinji; Sugawara, Fumio; Sahara, Hiroeki

    2014-11-01

    While the presentation mechanism of antigenic peptides derived from exogenous proteins by MHC class II molecules is well understood, relatively little is known about the presentation mechanism of endogenous MHC class II-restricted antigens. We therefore screened a chemical library of 200 compounds derived from natural products to identify inhibitors of the presentation of endogenous MHC class II-restricted antigens. We found that pyrenocine B, a compound derived from the fungus Pyrenochaeta terrestris, inhibits presentation of endogenous MHC class II-restricted minor histocompatibility antigen IL-4 inducible gene 1 (IL4I1) by primary dendritic cells (DCs). Phage display screening and surface plasmon resonance (SPR) analysis were used to investigate the mechanism of suppressive action by pyrenocine B. EpsinR, a target molecule for pyrenocine B, mediates endosomal trafficking through binding of soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). Lentiviral-mediated short hairpin (sh) RNA downregulation of EpsinR expression in DCs resulted in a decrease in the responsiveness of CD4+ T cells. Our data thus suggest that EpsinR plays a role in antigen presentation, which provides insight into the mechanism of presentation pathway of endogenous MHC class II-restricted antigen.

  1. Identification of Immunogenic Hot Spots within Plum Pox Potyvirus Capsid Protein for Efficient Antigen Presentation

    PubMed Central

    Fernández-Fernández, M. Rosario; Martínez-Torrecuadrada, Jorge L.; Roncal, Fernando; Domínguez, Elvira; García, Juan Antonio

    2002-01-01

    PEPSCAN analysis has been used to characterize the immunogenic regions of the capsid protein (CP) in virions of plum pox potyvirus (PPV). In addition to the well-known highly immunogenic N- and C-terminal domains of CP, regions within the core domain of the protein have also shown high immunogenicity. Moreover, the N terminus of CP is not homogeneously immunogenic, alternatively showing regions frequently recognized by antibodies and others that are not recognized at all. These results have helped us to design efficient antigen presentation vectors based on PPV. As predicted by PEPSCAN analysis, a small displacement of the insertion site in a previously constructed vector, PPV-γ, turned the derived chimeras into efficient immunogens. Vectors expressing foreign peptides at different positions within a highly immunogenic region (amino acids 43 to 52) in the N-terminal domain of CP were the most effective at inducing specific antibody responses against the foreign sequence. PMID:12438590

  2. Tubulin and Actin Interplay at the T Cell and Antigen-Presenting Cell Interface

    PubMed Central

    Martín-Cófreces, Noa Beatriz; Alarcón, Balbino; Sánchez-Madrid, Francisco

    2011-01-01

    T cells reorganize their actin and tubulin-based cytoskeletons to provide a physical basis to the immune synapse. However, growing evidence shows that their roles on T cell activation are more dynamic than merely serving as tracks or scaffold for different molecules. The crosstalk between both skeletons may be important for the formation and movement of the lamella at the immunological synapse by increasing the adhesion of the T cell to the antigen-presenting cells (APC), thus favoring the transport of components toward the plasma membrane and in turn regulating the T-APC intercellular communication. Microtubules and F-actin appear to be essential for the transport of the different signaling microclusters along the membrane, therefore facilitating the propagation of the signal. Finally, they can also be important for regulating the endocytosis, recycling, and degradation of the T cell receptor signaling machinery, thus helping both to sustain the activated state and to switch it off. PMID:22566814

  3. Identification of immunogenic hot spots within plum pox potyvirus capsid protein for efficient antigen presentation.

    PubMed

    Fernández-Fernández, M Rosario; Martínez-Torrecuadrada, Jorge L; Roncal, Fernando; Domínguez, Elvira; García, Juan Antonio

    2002-12-01

    PEPSCAN analysis has been used to characterize the immunogenic regions of the capsid protein (CP) in virions of plum pox potyvirus (PPV). In addition to the well-known highly immunogenic N- and C-terminal domains of CP, regions within the core domain of the protein have also shown high immunogenicity. Moreover, the N terminus of CP is not homogeneously immunogenic, alternatively showing regions frequently recognized by antibodies and others that are not recognized at all. These results have helped us to design efficient antigen presentation vectors based on PPV. As predicted by PEPSCAN analysis, a small displacement of the insertion site in a previously constructed vector, PPV-gamma, turned the derived chimeras into efficient immunogens. Vectors expressing foreign peptides at different positions within a highly immunogenic region (amino acids 43 to 52) in the N-terminal domain of CP were the most effective at inducing specific antibody responses against the foreign sequence.

  4. The role of antigen-presenting cells in filoviral hemorrhagic fever: gaps in current knowledge

    PubMed Central

    Martinez, Osvaldo; Leung, Lawrence W.; Basler, Christopher F.

    2012-01-01

    The filoviruses, ebolavirus (EBOV) and marburgvirus (MARV), are highly lethal zoonotic agents of concern as emerging pathogens and potential bioweapons. Antigen-presenting cells (APCs), particularly macrophages and dendritic cells, are targets of filovirus infection in vivo. Infection of these cell types has been proposed to contribute to the inflammation, activation of coagulation cascades and ineffective immune responses characteristic of filovirus hemorrhagic fever. However, many aspects of filovirus-APC interactions remain to be clarified. Among the unanswered questions: What determines the ability of filoviruses to replicate in different APC subsets? What are the cellular signaling pathways that sense infection and lead to production of copious quantities of cytokines, chemokines and tissue factor? What are the mechanisms by which innate antiviral responses are disabled by these viruses, and how may these mechanisms contribute to inadequate adaptive immunity? A better understanding of these issues will clarify the pathogenesis of filoviral hemorrhagic fever and provide new avenues for development of therapeutics. PMID:22333482

  5. Intestinal Antigen-Presenting Cells: Key Regulators of Immune Homeostasis and Inflammation.

    PubMed

    Flannigan, Kyle L; Geem, Duke; Harusato, Akihito; Denning, Timothy L

    2015-07-01

    The microbiota that populate the mammalian intestine are critical for proper host physiology, yet simultaneously pose a potential danger. Intestinal antigen-presenting cells, namely macrophages and dendritic cells (DCs), are integral components of the mucosal innate immune system that maintain co-existence with the microbiota in face of this constant threat. Intestinal macrophages and DCs integrate signals from the microenvironment to orchestrate innate and adaptive immune responses that ultimately lead to durable tolerance of the microbiota. Tolerance is not a default response, however, because macrophages and DCs remain poised to vigorously respond to pathogens that breach the epithelial barrier. In this review, we summarize the salient features of macrophages and DCs in the healthy and inflamed intestine and discuss how signals from the microbiota can influence their function.

  6. The Basics of Artificial Antigen Presenting Cells in T Cell-Based Cancer Immunotherapies.

    PubMed

    Neal, Lillian R; Bailey, Stefanie R; Wyatt, Megan M; Bowers, Jacob S; Majchrzak, Kinga; Nelson, Michelle H; Haupt, Carl; Paulos, Chrystal M; Varela, Juan C

    2017-01-01

    Adoptive T cell transfer (ACT) can mediate objective responses in patients with advanced malignancies. There have been major advances in this field, including the optimization of the ex vivo generation of tumor-reactive lymphocytes to ample numbers for effective ACT therapy via the use of natural and artificial antigen presenting cells (APCs). Herein we review the basic properties of APCs and how they have been manufactured through the years to augment vaccine and T cell-based cancer therapies. We then discuss how these novel APCs impact the function and memory properties of T cells. Finally, we propose new ways to synthesize aAPCs to augment the therapeutic effectiveness of antitumor T cells for ACT therapy.

  7. Emergence of distinct multi-armed immunoregulatory antigen presenting cells during persistent viral infection

    PubMed Central

    Wilson, Elizabeth B.; Kidani, Yoko; Elsaesser, Heidi; Barnard, Jennifer; Raff, Laura; Karp, Christopher L.; Bensinger, Steven; Brooks, David G.

    2012-01-01

    During persistent viral infection, adaptive immune responses are suppressed by immunoregulatory factors, contributing to viral persistence. Although this suppression is mediated by inhibitory factors, the mechanisms by which virus-specific T cells encounter and integrate immunoregulatory signals during persistent infection are unclear. We show that a distinct population of IL-10-expressing immunoregulatory antigen presenting cells (APC) is amplified during chronic versus acute lymphocytic choriomeningitis virus (LCMV) infection and suppresses T cell responses. Although acute LCMV infection induces the expansion of immunoregulatory APC, they subsequently decline. However, during persistent LCMV infection, immunoregulatory APC are amplified and parallel the viral replication kinetics. Further characterization demonstrates that immunoregulatory APC are molecularly and metabolically distinct, and exhibit increased expression of T cell-interacting molecules and negative regulatory factors that suppress T cell responses. Thus, immunoregulatory APC are amplified during viral persistence and deliver inhibitory signals that suppress antiviral T cell immunity and likely contribute to persistent infection. PMID:22607801

  8. CD169+ MACROPHAGES PRESENT LIPID ANTIGENS TO MEDIATE EARLY ACTIVATION OF INVARIANT NKT CELLS IN LYMPH NODES

    PubMed Central

    Barral, Patricia; Polzella, Paolo; Bruckbauer, Andreas; van Rooijen, Nico; Besra, Gurdyal S.; Cerundolo, Vincenzo; Batista, Facundo D.

    2010-01-01

    Invariant NKT (iNKT) cells are involved in host defence against microbial infections. While it is known that iNKT cells recognize glycolipids presented by CD1d, how and where they encounter antigen in vivo remains unclear. We used multi-photon microscopy to visualize the dynamics and activation of iNKT cells in lymph nodes. Following antigen administration, iNKT cells become confined in a CD1d-dependent manner in close proximity to subcapsular sinus CD169+ macrophages. These macrophages retain, internalize and present lipid antigen, and are required for iNKT cell activation, cytokine production and expansion. Thus, CD169+ macrophages can act as bona fide antigen presenting cells controlling early iNKT cell activation and favouring fast initiation of immune responses. PMID:20228797

  9. CD169(+) macrophages present lipid antigens to mediate early activation of iNKT cells in lymph nodes.

    PubMed

    Barral, Patricia; Polzella, Paolo; Bruckbauer, Andreas; van Rooijen, Nico; Besra, Gurdyal S; Cerundolo, Vincenzo; Batista, Facundo D

    2010-04-01

    Invariant natural killer T cells (iNKT cells) are involved in the host defense against microbial infection. Although it is known that iNKT cells recognize glycolipids presented by CD1d, how and where they encounter antigen in vivo remains unclear. Here we used multiphoton microscopy to visualize the dynamics and activation of iNKT cells in lymph nodes. After antigen administration, iNKT cells became confined in a CD1d-dependent manner in close proximity to subcapsular sinus CD169(+) macrophages. These macrophages retained, internalized and presented lipid antigen and were required for iNKT cell activation, cytokine production and population expansion. Thus, CD169(+) macrophages can act as true antigen-presenting cells controlling early iNKT cell activation and favoring the fast initiation of immune responses.

  10. Expression profile of novel cell surface molecules on different subsets of human peripheral blood antigen-presenting cells

    PubMed Central

    Damasceno, Daniela; Andrés, Martín Pérez; van den Bossche, Wouter BL; Flores-Montero, Juan; de Bruin, Sandra; Teodosio, Cristina; van Dongen, Jacques JM; Orfao, Alberto; Almeida, Julia

    2016-01-01

    Although major steps have been recently made in understanding the role of the distinct subsets of dendritic cells (DC)/antigen-presenting cells (APC), further studies are required to unravel their precise role, including in-depth immunophenotypic characterisation of these cells. Here, we used eight-colour flow cytometry to investigate the reactivity of a panel of 72 monoclonal antibodies (including those clustered in seven new Cluster of Differentiation, CD) on different subsets of APC in peripheral blood (PB) samples from five healthy adults. These experiments were performed in the context of the Tenth International Workshop on Human Leukocyte Differentiation Antigens (HLDA10). Plasmacytoid DC was the only cell population that expressed CD85g and CD195, whereas they lacked all of the other molecules investigated. In contrast, myeloid DC mostly expressed inhibitory C-type lectin receptors (CLRs) and other inhibitory-associated molecules, whereas monocytes expressed both inhibitory and activating CLRs, together with other phagocytosis-associated receptors. Within monocytes, progressively lower levels of expression were generally observed from classical monocytes (cMo) to SLAN− and SLAN+ non-classical monocytes (ncMo) for most of the molecules expressed, except for the CD368 endocytic receptor. This molecule was found to be positive only in cMo, and the CD369 and CD371 modulating/signalling receptors. In addition, the CD101 inhibitory molecule was found to be expressed at higher levels in SLAN+ vs SLAN− ncMo. In summary, the pattern of expression of the different signalling molecules and receptors analysed in this work varies among the distinct subsets of PB APCs, with similar profiles for molecules within each functional group. These findings suggest unique pattern-recognition and signalling capabilities for distinct subpopulations of APCs, and therefore, diverse functional roles. PMID:27766148

  11. Accelerator Mass Spectrometry Detection of Beryllium Ions in the Antigen Processing and Presentation Pathway

    PubMed Central

    Tooker, Brian C.; Brindley, Stephen M.; Chiarappa-Zucca, Marina L.; Turteltaub, Kenneth W.; Newman, Lee S.

    2015-01-01

    Exposure to small amounts of beryllium (Be) can result in beryllium sensitization and progression to Chronic Beryllium Disease (CBD). In CBD, beryllium is presented to Be-responsive T-cells by professional antigen-presenting cells (APC). This presentation drives T-cell proliferation and pro-inflammatory cytokine (IL-2, TNFα, and IFNγ) production and leads to granuloma formation. The mechanism by which beryllium enters an APC and is processed to become part of the beryllium antigen complex has not yet been elucidated. Developing techniques for beryllium detection with enough sensitivity has presented a barrier to further investigation. The objective of this study was to demonstrate that Accelerator Mass Spectrometry (AMS) is sensitive enough to quantify the amount of beryllium presented by APC to stimulate Be-responsive T-cells. To achieve this goal, APC - which may or may not stimulate Be-responsive T-cells - were cultured with Be-ferritin. Then, by utilizing AMS, the amount of beryllium processed for presentation was determined. Further, IFNγ intracellular cytokine assays were performed to demonstrate that Be-ferritin (at levels used in the experiments) could stimulate Be-responsive T-cells when presented by an APC of the correct HLA type (HLA-DP0201). The results indicated that Be-responsive T-cells expressed IFNγ only when APC with the correct HLA type were able to process Be for presentation. Utilizing AMS, it was determined that APC with HLA-DP0201 had membrane fractions containing 0.17-0.59 ng Be and APC with HLA-DP0401 had membrane fractions bearing 0.40-0.45 ng Be. However, HLA-DP0401 APC had 20-times more Be associated with the whole cells (57.68-61.12 ng) then HLA-DP0201 APC (0.90-3.49 ng). As these findings demonstrate, AMS detection of picogram levels of Be processed by APC is possible. Further, regardless of form, Be requires processing by APC to successfully stimulate Be-responsive T-cells to generate IFNγ. PMID:24932923

  12. Accelerator mass spectrometry detection of beryllium ions in the antigen processing and presentation pathway.

    PubMed

    Tooker, Brian C; Brindley, Stephen M; Chiarappa-Zucca, Marina L; Turteltaub, Kenneth W; Newman, Lee S

    2015-01-01

    Exposure to small amounts of beryllium (Be) can result in beryllium sensitization and progression to Chronic Beryllium Disease (CBD). In CBD, beryllium is presented to Be-responsive T-cells by professional antigen-presenting cells (APC). This presentation drives T-cell proliferation and pro-inflammatory cytokine (IL-2, TNFα, and IFNγ) production and leads to granuloma formation. The mechanism by which beryllium enters an APC and is processed to become part of the beryllium antigen complex has not yet been elucidated. Developing techniques for beryllium detection with enough sensitivity has presented a barrier to further investigation. The objective of this study was to demonstrate that Accelerator Mass Spectrometry (AMS) is sensitive enough to quantify the amount of beryllium presented by APC to stimulate Be-responsive T-cells. To achieve this goal, APC - which may or may not stimulate Be-responsive T-cells - were cultured with Be-ferritin. Then, by utilizing AMS, the amount of beryllium processed for presentation was determined. Further, IFNγ intracellular cytokine assays were performed to demonstrate that Be-ferritin (at levels used in the experiments) could stimulate Be-responsive T-cells when presented by an APC of the correct HLA type (HLA-DP0201). The results indicated that Be-responsive T-cells expressed IFNγ only when APC with the correct HLA type were able to process Be for presentation. Utilizing AMS, it was determined that APC with HLA-DP0201 had membrane fractions containing 0.17-0.59 ng Be and APC with HLA-DP0401 had membrane fractions bearing 0.40-0.45 ng Be. However, HLA-DP0401 APC had 20-times more Be associated with the whole cells (57.68-61.12 ng) than HLA-DP0201 APC (0.90-3.49 ng). As these findings demonstrate, AMS detection of picogram levels of Be processed by APC is possible. Further, regardless of form, Be requires processing by APC to successfully stimulate Be-responsive T-cells to generate IFNγ.

  13. Accelerator mass spectrometry detection of beryllium ions in the antigen processing and presentation pathway

    SciTech Connect

    Tooker, Brian C.; Brindley, Stephen M.; Chiarappa-Zucca, Marina L.; Turteltaub, Kenneth W.; Newman, Lee S.

    2014-06-16

    We report that exposure to small amounts of beryllium (Be) can result in beryllium sensitization and progression to Chronic Beryllium Disease (CBD). In CBD, beryllium is presented to Be-responsive T-cells by professional antigen-presenting cells (APC). This presentation drives T-cell proliferation and pro-inflammatory cytokine (IL-2, TNFα, and IFNγ) production and leads to granuloma formation. The mechanism by which beryllium enters an APC and is processed to become part of the beryllium antigen complex has not yet been elucidated. Developing techniques for beryllium detection with enough sensitivity has presented a barrier to further investigation. The objective of this study was to demonstrate that Accelerator Mass Spectrometry (AMS) is sensitive enough to quantify the amount of beryllium presented by APC to stimulate Be-responsive T-cells. To achieve this goal, APC - which may or may not stimulate Be-responsive T-cells - were cultured with Be-ferritin. Then, by utilizing AMS, the amount of beryllium processed for presentation was determined. Further, IFNγ intracellular cytokine assays were performed to demonstrate that Be-ferritin (at levels used in the experiments) could stimulate Be-responsive T-cells when presented by an APC of the correct HLA type (HLA-DP0201). The results indicated that Be-responsive T-cells expressed IFNγ only when APC with the correct HLA type were able to process Be for presentation. Utilizing AMS, we determined that APC with HLA-DP0201 had membrane fractions containing 0.17-0.59 ng Be and APC with HLA-DP0401 had membrane fractions bearing 0.40-0.45 ng Be. However, HLA-DP0401 APC had 20-times more Be associated with the whole cells (57.68-61.12 ng) then HLA-DP0201 APC (0.90-3.49 ng). As these findings demonstrate, AMS detection of picogram levels of Be processed by APC is possible. Further, regardless of form, Be requires processing by APC to successfully stimulate Be-responsive T-cells to generate IFNγ.

  14. Accelerator mass spectrometry detection of beryllium ions in the antigen processing and presentation pathway

    DOE PAGES

    Tooker, Brian C.; Brindley, Stephen M.; Chiarappa-Zucca, Marina L.; ...

    2014-06-16

    We report that exposure to small amounts of beryllium (Be) can result in beryllium sensitization and progression to Chronic Beryllium Disease (CBD). In CBD, beryllium is presented to Be-responsive T-cells by professional antigen-presenting cells (APC). This presentation drives T-cell proliferation and pro-inflammatory cytokine (IL-2, TNFα, and IFNγ) production and leads to granuloma formation. The mechanism by which beryllium enters an APC and is processed to become part of the beryllium antigen complex has not yet been elucidated. Developing techniques for beryllium detection with enough sensitivity has presented a barrier to further investigation. The objective of this study was to demonstratemore » that Accelerator Mass Spectrometry (AMS) is sensitive enough to quantify the amount of beryllium presented by APC to stimulate Be-responsive T-cells. To achieve this goal, APC - which may or may not stimulate Be-responsive T-cells - were cultured with Be-ferritin. Then, by utilizing AMS, the amount of beryllium processed for presentation was determined. Further, IFNγ intracellular cytokine assays were performed to demonstrate that Be-ferritin (at levels used in the experiments) could stimulate Be-responsive T-cells when presented by an APC of the correct HLA type (HLA-DP0201). The results indicated that Be-responsive T-cells expressed IFNγ only when APC with the correct HLA type were able to process Be for presentation. Utilizing AMS, we determined that APC with HLA-DP0201 had membrane fractions containing 0.17-0.59 ng Be and APC with HLA-DP0401 had membrane fractions bearing 0.40-0.45 ng Be. However, HLA-DP0401 APC had 20-times more Be associated with the whole cells (57.68-61.12 ng) then HLA-DP0201 APC (0.90-3.49 ng). As these findings demonstrate, AMS detection of picogram levels of Be processed by APC is possible. Further, regardless of form, Be requires processing by APC to successfully stimulate Be-responsive T-cells to generate IFNγ.« less

  15. Accelerator mass spectrometry detection of beryllium ions in the antigen processing and presentation pathway

    SciTech Connect

    Tooker, Brian C.; Brindley, Stephen M.; Chiarappa-Zucca, Marina L.; Turteltaub, Kenneth W.; Newman, Lee S.

    2014-06-16

    Exposure to small amounts of beryllium (Be) can result in beryllium sensitization and progression to Chronic Beryllium Disease (CBD). In CBD, beryllium is presented to Be-responsive T-cells by professional antigen-presenting cells (APC). This presentation drives T-cell proliferation and pro-inflammatory cytokine (IL-2, TNFα, and IFNγ) production and leads to granuloma formation. The mechanism by which beryllium enters an APC and is processed to become part of the beryllium antigen complex has not yet been elucidated. Developing techniques for beryllium detection with enough sensitivity has presented a barrier to further investigation. The objective of this study was to demonstrate that Accelerator Mass Spectrometry (AMS) is sensitive enough to quantify the amount of beryllium presented by APC to stimulate Be-responsive T-cells. To achieve this goal, APC - which may or may not stimulate Be-responsive T-cells - were cultured with Be-ferritin. Then, by utilizing AMS, the amount of beryllium processed for presentation was determined. Further, IFNγ intracellular cytokine assays were performed to demonstrate that Be-ferritin (at levels used in the experiments) could stimulate Be-responsive T-cells when presented by an APC of the correct HLA type (HLA-DP0201). The results indicated that Be-responsive T-cells expressed IFNγ only when APC with the correct HLA type were able to process Be for presentation. Utilizing AMS, it was determined that APC with HLA-DP0201 had membrane fractions containing 0.17-0.59 ng Be and APC with HLA-DP0401 had membrane fractions bearing 0.40-0.45 ng Be. However, HLA-DP0401 APC had 20-times more Be associated with the whole cells (57.68-61.12 ng) than HLA-DP0201 APC (0.90-3.49 ng). As these findings demonstrate, AMS detection of picogram levels of Be processed by APC is possible. Further, regardless of form, Be requires processing by APC to successfully stimulate Be-responsive T-cells to generate IFNγ.

  16. Accelerator mass spectrometry detection of beryllium ions in the antigen processing and presentation pathway

    DOE PAGES

    Tooker, Brian C.; Brindley, Stephen M.; Chiarappa-Zucca, Marina L.; ...

    2014-06-16

    Exposure to small amounts of beryllium (Be) can result in beryllium sensitization and progression to Chronic Beryllium Disease (CBD). In CBD, beryllium is presented to Be-responsive T-cells by professional antigen-presenting cells (APC). This presentation drives T-cell proliferation and pro-inflammatory cytokine (IL-2, TNFα, and IFNγ) production and leads to granuloma formation. The mechanism by which beryllium enters an APC and is processed to become part of the beryllium antigen complex has not yet been elucidated. Developing techniques for beryllium detection with enough sensitivity has presented a barrier to further investigation. The objective of this study was to demonstrate that Accelerator Massmore » Spectrometry (AMS) is sensitive enough to quantify the amount of beryllium presented by APC to stimulate Be-responsive T-cells. To achieve this goal, APC - which may or may not stimulate Be-responsive T-cells - were cultured with Be-ferritin. Then, by utilizing AMS, the amount of beryllium processed for presentation was determined. Further, IFNγ intracellular cytokine assays were performed to demonstrate that Be-ferritin (at levels used in the experiments) could stimulate Be-responsive T-cells when presented by an APC of the correct HLA type (HLA-DP0201). The results indicated that Be-responsive T-cells expressed IFNγ only when APC with the correct HLA type were able to process Be for presentation. Utilizing AMS, it was determined that APC with HLA-DP0201 had membrane fractions containing 0.17-0.59 ng Be and APC with HLA-DP0401 had membrane fractions bearing 0.40-0.45 ng Be. However, HLA-DP0401 APC had 20-times more Be associated with the whole cells (57.68-61.12 ng) than HLA-DP0201 APC (0.90-3.49 ng). As these findings demonstrate, AMS detection of picogram levels of Be processed by APC is possible. Further, regardless of form, Be requires processing by APC to successfully stimulate Be-responsive T-cells to generate IFNγ.« less

  17. Extracts from presumed "reduced harm" cigarettes induce equivalent or greater toxicity in antigen-presenting cells.

    PubMed

    Vassallo, Robert; Wang, Lei; Hirano, Yoshimi; Walters, Paula; Grill, Diane

    2015-09-01

    The tobacco industry has promoted certain cigarette products with claims that their use may be less harmful to the smoker as they purportedly deliver lower amounts of toxic chemicals compared to conventional cigarettes. This study was designed to compare the relative antigen presenting cellular toxicity of Eclipse, a presumed reduced exposure product (PREP) cigarette, when compared with the reference research 3R4F cigarettes (Kentucky University). Utilizing a murine macrophage cell line, murine bone marrow derived dendritic cells (DCs) and human monocyte-derived DCs incubated with extracts generated from Eclipse and Kentucky reference 3R4F cigarettes, we determined the relative toxic effects of the different cigarette smoke extracts on cellular viability, oxidative stress, T-helper-1 (Th-1) polarizing cytokine production and general gene expression. Eclipse and 3R4F cigarette smoke extracts induced equivalent oxidatively-mediated cellular heme oxygenase-1 (HO-1) protein levels in macrophages and DCs. Cellular viability determination demonstrated greater induction of cell death by apoptosis and necrosis by Eclipse extracts in DCs. The production of the key Th-1 polarizing cytokine interleukin-12 (IL-12) by activated DCs or macrophages was suppressed to an equivalent or greater extent by Eclipse extracts. Microarray studies performed on bone marrow derived murine DCs incubated with Eclispe or 3R4F cigarette extracts showed identical genotoxic profiles. These studies imply that presumed reduced harm Eclipse cigarettes induce equivalent or greater antigen presenting cell dysfunction relative to 3R4F cigarettes and illustrate the importance of independent validation and testing of similar products claimed to be associated with reduced toxicity relative to other cigarettes.

  18. An Evolutionary Analysis of Antigen Processing and Presentation across Different Timescales Reveals Pervasive Selection

    PubMed Central

    Tresoldi, Claudia; Pozzoli, Uberto; De Gioia, Luca; Filippi, Giulia; Riva, Stefania; Menozzi, Giorgia; Colleoni, Marta; Biasin, Mara; Lo Caputo, Sergio; Mazzotta, Francesco; Comi, Giacomo P.; Bresolin, Nereo; Clerici, Mario; Sironi, Manuela

    2014-01-01

    The antigenic repertoire presented by MHC molecules is generated by the antigen processing and presentation (APP) pathway. We analyzed the evolutionary history of 45 genes involved in APP at the inter- and intra-species level. Results showed that 11 genes evolved adaptively in mammals. Several positively selected sites involve positions of fundamental importance to the protein function (e.g. the TAP1 peptide-binding domains, the sugar binding interface of langerin, and the CD1D trafficking signal region). In CYBB, all selected sites cluster in two loops protruding into the endosomal lumen; analysis of missense mutations responsible for chronic granulomatous disease (CGD) showed the action of different selective forces on the very same gene region, as most CGD substitutions involve aminoacid positions that are conserved in all mammals. As for ERAP2, different computational methods indicated that positive selection has driven the recurrent appearance of protein-destabilizing variants during mammalian evolution. Application of a population-genetics phylogenetics approach showed that purifying selection represented a major force acting on some APP components (e.g. immunoproteasome subunits and chaperones) and allowed identification of positive selection events in the human lineage. We also investigated the evolutionary history of APP genes in human populations by developing a new approach that uses several different tests to identify the selection target, and that integrates low-coverage whole-genome sequencing data with Sanger sequencing. This analysis revealed that 9 APP genes underwent local adaptation in human populations. Most positive selection targets are located within noncoding regions with regulatory function in myeloid cells or act as expression quantitative trait loci. Conversely, balancing selection targeted nonsynonymous variants in TAP1 and CD207 (langerin). Finally, we suggest that selected variants in PSMB10 and CD207 contribute to human phenotypes

  19. Identification of a Mouse Cytomegalovirus Gene Selectively Targeting CD86 Expression on Antigen-Presenting Cells

    PubMed Central

    Loewendorf, Andrea; Krüger, Corinna; Borst, Eva Maria; Wagner, Markus; Just, Ursula; Messerle, Martin

    2004-01-01

    We and others have shown that infection of dendritic cells with murine cytomegalovirus (MCMV) leads to severe functional impairment of these antigen-presenting cells (D. M. Andrews, C. E. Andoniou, F. Granucci, P. Ricciardi-Castagnoli, and M. A. Degli-Esposti, Nat. Immunol. 2:1077-1084, 2001; S. Mathys, T. Schroeder, J. Ellwart, U. H. Koszinowski, M. Messerle, and U. Just, J. Infect. Dis. 187:988-999, 2003). Phenotypically, reduced surface expression of costimulatory molecules and major histocompatibility complex molecules was detected. In order to identify the molecular basis for the observed effects, we generated MCMV mutants with large deletions of nonessential genes. The study was facilitated by the finding that a monocyte-macrophage cell line displayed similar phenotypic alterations after MCMV infection. By analyzing the expression of cell surface molecules on infected cells, we identified a mutant virus which is no longer able to downmodulate the expression of the costimulatory molecule CD86. Additional mutants with smaller deletions allowed us to pin down the responsible gene to a certain genomic region. RNA analysis led to the identification of the spliced gene m147.5, encoding a protein with 145 amino acids. Experiments with an m147.5 mutant revealed that the protein affects CD86 expression only, suggesting that additional MCMV genes are responsible for downmodulation of the other surface molecules. Identification of viral gene products interfering with functionally important proteins of antigen-presenting cells will provide the basis to dissect the complex interaction of CMV with these important cells and to evaluate the biological importance of these viral genes in vivo. PMID:15542658

  20. Characterization of antigen-presenting cells from the porcine respiratory system.

    PubMed

    López-Robles, Guadalupe; Silva-Campa, Erika; Burgara-Estrella, Alexel; Hernández, Jesús

    2015-06-01

    Antigen-presenting cells (APCs) are strategically placed in all anatomic sites with high antigen exposure such as the respiratory system. The aim of this study was to evaluate phenotypic and functional properties of APCs from the lung (L-Cs), mediastinal lymph node (LN-Cs) and bronchoalveolar lavage cells (BAL-Cs). The APCs were first analyzed based on forward scatter and side scatter profiles and the selection of MHC-II(high)CD172a(+) cells (referred to as APCs); then the expression of CD1a, CD163, CD206, CD16 and CD11R3 was evaluated in the APCs. The results showed that CD1a, CD163 and CD206 were differentially expressed among L-Cs, LN-Cs and BAL-Cs, suggesting the phenotype MHC-II(high)CD172a(+)CD1a(low/-)CD163(low)CD206(-) for L-Cs and MHC-II(high)CD172a(+)CD1a(+)CD163(low/-)CD206(+) for LN-Cs. BAL-Cs were MHC-II(high)CD172a(+)CD1a(-)CD163(high)CD206(+/-). The functional characteristics of L-Cs and LN-Cs were different from those of BAL-Cs, confirming that L-Cs and LN-Cs resemble specialized APCs. In conclusion, we present the characterization of APCs from L-Cs, LN-Cs and BAL-Cs of the porcine respiratory system.

  1. Spatiotemporally separated antigen uptake by alveolar dendritic cells and airway presentation to T cells in the lung

    PubMed Central

    Thornton, Emily E.; Looney, Mark R.; Bose, Oishee; Sen, Debasish; Sheppard, Dean; Locksley, Richard; Huang, Xiaozhu

    2012-01-01

    Asthma pathogenesis is focused around conducting airways. The reasons for this focus have been unclear because it has not been possible to track the sites and timing of antigen uptake or subsequent antigen presentation to effector T cells. In this study, we use two-photon microscopy of the lung parenchyma and note accumulation of CD11b+ dendritic cells (DCs) around the airway after allergen challenge but very limited access of these airway-adjacent DCs to the contents of the airspace. In contrast, we observed prevalent transepithelial uptake of particulate antigens by alveolar DCs. These distinct sites are temporally linked, as early antigen uptake in alveoli gives rise to DC and antigen retention in the airway-adjacent region. Antigen-specific T cells also accumulate in the airway-adjacent region after allergen challenge and are activated by the accumulated DCs. Thus, we propose that later airway hyperreactivity results from selective retention of allergen-presenting DCs and antigen-specific T cells in airway-adjacent interaction zones, not from variation in the abilities of individual DCs to survey the lung. PMID:22585735

  2. Predominant role for directly transfected dendritic cells in antigen presentation to CD8+ T cells after gene gun immunization.

    PubMed

    Porgador, A; Irvine, K R; Iwasaki, A; Barber, B H; Restifo, N P; Germain, R N

    1998-09-21

    Cutaneous gene (DNA) bombardment results in substantial expression of the encoded antigen in the epidermal layer as well as detectable expression in dendritic cells (DC) in draining lymph nodes (LNs). Under these conditions, two possible modes of DC antigen presentation to naive CD8+ T cells might exist: (a) presentation directly by gene-transfected DC trafficking to local lymph nodes, and (b) cross-presentation by untransfected DC of antigen released from or associated with transfected epidermal cells. The relative contributions of these distinct modes of antigen presentation to priming for cytotoxic T cell (CTL) responses have not been clearly established. Here we show that LN cells directly expressing the DNA-encoded antigen are rare; 24 h after five abdominal skin bombardments, the number of these cells does not exceed 50-100 cells in an individual draining LN. However, over this same time period, the total number of CD11c+ DC increases more than twofold, by an average of 20,000-30,000 DC per major draining node. This augmentation is due to gold bombardment and is independent of the presence of plasmid DNA. Most antigen-bearing cells in the LNs draining the site of DNA delivery appear to be DC and can be depleted by antibodies to an intact surface protein encoded by cotransfected DNA. This finding of predominant antigen presentation by directly transfected cells is also consistent with data from studies on cotransfection with antigen and CD86-encoding DNA, showing that priming of anti-mutant influenza nucleoprotein CTLs with a single immunization is dependent upon coexpression of the DNAs encoding nucleoprotein and B7.2 in the same cells. These observations provide insight into the relative roles of direct gene expression and cross-presentation in CD8+ T cell priming using gene gun immunization, and indicate that augmentation of direct DC gene expression may enhance such priming.

  3. The Toll-like receptor 9 signalling pathway regulates MR1-mediated bacterial antigen presentation in B cells.

    PubMed

    Liu, Jianyun; Brutkiewicz, Randy R

    2017-10-01

    Mucosal-associated invariant T (MAIT) cells are conserved T cells that express a semi-invariant T-cell receptor (Vα7.2 in humans and Vα19 in mice). The development of MAIT cells requires the antigen-presenting MHC-related protein 1 (MR1), as well as commensal bacteria. The mechanisms that regulate the functional expression of MR1 molecules and their loading with bacterial antigen in antigen-presenting cells are largely unknown. We have found that treating B cells with the Toll-like receptor 9 (TLR9) agonist CpG increases MR1 surface expression. Interestingly, activation of TLR9 by CpG-A (but not CpG-B) enhances MR1 surface expression. This is limited to B cells and not other types of cells such as monocytes, T or natural killer cells. Knocking-down TLR9 expression by short hairpin RNA reduces MR1 surface expression and MR1-mediated bacterial antigen presentation. CpG-A triggers early endosomal TLR9 activation, whereas CpG-B is responsible for late endosomal/lysosomal activation of TLR9. Consistently, blocking endoplasmic reticulum to Golgi protein transport, rather than lysosomal acidification, suppressed MR1 antigen presentation. Overall, our results indicate that early endosomal TLR9 activation is important for MR1-mediated bacterial antigen presentation. © 2017 John Wiley & Sons Ltd.

  4. Changes in antigen-presenting cell function in the spleen and lymph nodes of ultraviolet-irradiated mice

    SciTech Connect

    Gurish, M.F.; Lynch, D.H.; Daynes, R.A.

    1982-03-01

    It has been previously reported that mice exposed to ultraviolet (UV) radiation exhibit a decrease in splenic antigen-presenting cell (APC) function. The results presented here confirm this observation and further demonstrate that animals exposed daily to UV for extended periods of time (5 weeks instead of 6 days) no longer exhibit this depressed capability. In spite of the depression in splenic APC activity found in 6-day UV-irradiated mice, lymph node APC function from these same animals was elevated compared with that found in the lymph nodes from normal animals. Lymph node APC activity in animals that were splenectomized prior to the UV irradiation, however, was not enhanced over controls. Treatment of animals with a chemical irritant (turpentine) also caused a depression in splenic APC function without modifying lymph node activity. Collectively, our findings suggest that the observed decrease in splenic APC activity, found after the first week of UV exposures, may be attributable to the migration of splenic APC to peripheral lymphoid tissue which drain the site of epidermal inflammation.

  5. Polymer nanoparticles for cross-presentation of exogenous antigens and enhanced cytotoxic T-lymphocyte immune response

    PubMed Central

    Song, Chanyoung; Noh, Young-Woock; Lim, Yong Taik

    2016-01-01

    Effective induction of an antigen-specific cytotoxic T lymphocyte (CTL) immune response is one of the key goals of cancer immunotherapy. We report the design and fabrication of polyethylenimine (PEI)-coated polymer nanoparticles (NPs) as efficient antigen-delivery carriers that can induce antigen cross-presentation and a strong CTL response. After synthesis of poly(d,l-lactide-co-glycolide) (PLGA) NPs containing ovalbumin (OVA) by the double-emulsion solvent-evaporation method, cationic-charged PLGA NPs were generated by coating them with PEI. In a methyl tetrazolium salt assay, no discernible cytotoxic effect of PEI-coated PLGA (OVA) NPs was observed. The capacity and mechanism of PEI-coated PLGA (OVA) NPs for antigen delivery and cross-presentation on dendritic cells (DCs) were determined by fluorescence microscopy and flow cytometry. PEI-coated PLGA (OVA) NPs were internalized efficiently via phagocytosis or macropinocytosis in DCs and induced efficient cross-presentation of the antigen on MHC class I molecules via both endosome escape and a lysosomal processing mechanism. The DCs treated with PEI-coated PLGA (OVA) NPs induced a release of IL-2 cytokine from OVA-specific CD8-OVA1.3 T cells more efficiently than DCs treated with PLGA (OVA) NPs. Therefore, the PEI-coated PLGA (OVA) NPs can induce antigen cross-presentation and are expected to be used for induction of a strong CTL immune response and for efficient anticancer immunotherapy. PMID:27540289

  6. Modulation of liver tolerance by conventional and nonconventional antigen-presenting cells and regulatory immune cells

    PubMed Central

    Horst, Andrea Kristina; Neumann, Katrin; Diehl, Linda; Tiegs, Gisa

    2016-01-01

    The liver is a tolerogenic organ with exquisite mechanisms of immune regulation that ensure upkeep of local and systemic immune tolerance to self and foreign antigens, but that is also able to mount effective immune responses against pathogens. The immune privilege of liver allografts was recognized first in pigs in spite of major histo-compatibility complex mismatch, and termed the “liver tolerance effect”. Furthermore, liver transplants are spontaneously accepted with only low-dose immunosuppression, and induce tolerance for non-hepatic co-transplanted allografts of the same donor. Although this immunotolerogenic environment is favorable in the setting of organ transplantation, it is detrimental in chronic infectious liver diseases like hepatitis B or C, malaria, schistosomiasis or tumorigenesis, leading to pathogen persistence and weak anti-tumor effects. The liver is a primary site of T-cell activation, but it elicits poor or incomplete activation of T cells, leading to their abortive activation, exhaustion, suppression of their effector function and early death. This is exploited by pathogens and can impair pathogen control and clearance or allow tumor growth. Hepatic priming of T cells is mediated by a number of local conventional and nonconventional antigen-presenting cells (APCs), which promote tolerance by immune deviation, induction of T-cell anergy or apoptosis, and generating and expanding regulatory T cells. This review will focus on the communication between classical and nonclassical APCs and lymphocytes in the liver in tolerance induction and will discuss recent insights into the role of innate lymphocytes in this process. PMID:27041638

  7. Engineered artificial antigen presenting cells facilitate direct and efficient expansion of tumor infiltrating lymphocytes

    PubMed Central

    2011-01-01

    Background Development of a standardized platform for the rapid expansion of tumor-infiltrating lymphocytes (TILs) with anti-tumor function from patients with limited TIL numbers or tumor tissues challenges their clinical application. Methods To facilitate adoptive immunotherapy, we applied genetically-engineered K562 cell-based artificial antigen presenting cells (aAPCs) for the direct and rapid expansion of TILs isolated from primary cancer specimens. Results TILs outgrown in IL-2 undergo rapid, CD28-independent expansion in response to aAPC stimulation that requires provision of exogenous IL-2 cytokine support. aAPCs induce numerical expansion of TILs that is statistically similar to an established rapid expansion method at a 100-fold lower feeder cell to TIL ratio, and greater than those achievable using anti-CD3/CD28 activation beads or extended IL-2 culture. aAPC-expanded TILs undergo numerical expansion of tumor antigen-specific cells, remain amenable to secondary aAPC-based expansion, and have low CD4/CD8 ratios and FOXP3+ CD4+ cell frequencies. TILs can also be expanded directly from fresh enzyme-digested tumor specimens when pulsed with aAPCs. These "young" TILs are tumor-reactive, positively skewed in CD8+ lymphocyte composition, CD28 and CD27 expression, and contain fewer FOXP3+ T cells compared to parallel IL-2 cultures. Conclusion Genetically-enhanced aAPCs represent a standardized, "off-the-shelf" platform for the direct ex vivo expansion of TILs of suitable number, phenotype and function for use in adoptive immunotherapy. PMID:21827675

  8. Interaction of Cowpea mosaic virus (CPMV) nanoparticles with antigen presenting cells in vitro and in vivo.

    PubMed

    Gonzalez, Maria J; Plummer, Emily M; Rae, Chris S; Manchester, Marianne

    2009-11-23

    Plant viruses such as Cowpea mosaic virus (CPMV) are increasingly being developed for applications in nanobiotechnology including vaccine development because of their potential for producing large quantities of antigenic material in plant hosts. In order to improve efficacy of viral nanoparticles in these types of roles, an investigation of the individual cell types that interact with the particles is critical. In particular, it is important to understand the interactions of a potential vaccine with antigen presenting cells (APCs) of the immune system. CPMV was previously shown to interact with vimentin displayed on cell surfaces to mediate cell entry, but the expression of surface vimentin on APCs has not been characterized. The binding and internalization of CPMV by several populations of APCs was investigated both in vitro and in vivo by flow cytometry and fluorescence confocal microscopy. The association of the particles with mouse gastrointestinal epithelium and Peyer's patches was also examined by confocal microscopy. The expression of surface vimentin on APCs was also measured. We found that CPMV is bound and internalized by subsets of several populations of APCs both in vitro and in vivo following intravenous, intraperitoneal, and oral administration, and also by cells isolated from the Peyer's patch following gastrointestinal delivery. Surface vimentin was also expressed on APC populations that could internalize CPMV. These experiments demonstrate that APCs capture CPMV particles in vivo, and that further tuning the interaction with surface vimentin may facilitate increased uptake by APCs and priming of antibody responses. These studies also indicate that CPMV particles likely access the systemic circulation following oral delivery via the Peyer's patch.

  9. Cross-Presentation of Cell-Associated Antigens by Mouse Splenic Dendritic Cell Populations

    PubMed Central

    Thacker, Robert I.; Janssen, Edith M.

    2012-01-01

    Cross-presentation of cell-associated antigens (Ag) plays an important role in the induction of anti-tumor responses, autoimmune diseases, and transplant rejection. While several dendritic cell (DC) populations can induce pro-inflammatory CD8+ T cell responses to cell-associated Ag during infection, in the absence of infection, cross-priming of naïve CD8+ T cells is highly restricted. Comparison of the main splenic DC populations in mice – including the classic, cross-presenting CD8α DC and the recently described merocytic DC (mcDC) – reveals that cross-priming DCs display a distinct phenotype in cell-associated Ag uptake, endosomal/lysosomal trafficking, lysosomal acidification, and Ag persistence compared to non-cross-priming DC populations. Although the CD8α DC and mcDC subsets utilize similar processing pathways to cross-present cell-associated Ag, cross-priming by CD8α DCs is associated with IL-12 production, while the superior priming of the mcDC is critically dependent on type I IFN production. This discussion illustrates how subtle differences in internal processing pathways and their signaling sequelae significantly affect the duration of Ag cross-presentation and cytokine production by DCs, thereby shaping the ensuing CD8+ T cell response. PMID:22566924

  10. Murine epidermal antigen-presenting cells in primary and secondary T-cell proliferative responses to a soluble protein antigen in vitro.

    PubMed Central

    Williams, N A; Hill, T J; Hooper, D C

    1990-01-01

    The capacity of epidermal cells (EC) to present antigen to primed and non-immune T cells was investigated using a culture system that supports antigen-specific primary and secondary proliferative responses. Although both naive and bovine serum albumin (BSA)-immune T cells reacted against BSA in the presence of either splenic or epidermal antigen-presenting cells (APC), important differences were noted in the kinetics and the magnitudes of the various responses. Most conspicuous was the relatively poor primary response supported by EC which evidently elicited very few BSA-immune T-helper cells. Despite this, the primed antigen-specific T cells recovered were phenotypically similar to those resulting from the stronger primary responses induced by spleen cells. In contrast to this disparity in the ability to prime, EC and spleen cells stimulated secondary reactions of comparable magnitude. We therefore consider that, in comparison with splenic APC, EC may require some additional stimulus to acquire the capacity to prime. PMID:2148541

  11. Uptake of biodegradable poly(γ-glutamic acid) nanoparticles and antigen presentation by dendritic cells in vivo.

    PubMed

    Uto, Tomofumi; Toyama, Masaaki; Nishi, Yosuke; Akagi, Takami; Shima, Fumiaki; Akashi, Mitsuru; Baba, Masanori

    2013-01-01

    Poly(γ-glutamic acid) (γ-PGA) nanoparticles (NPs) carrying antigens have been shown to induce potent antigen-specific immune responses. However, in vivo delivery of γ-PGA NPs to dendritic cells (DCs), a key regulator of immune responses, still remains unclear. In this study, γ-PGA NPs were examined for their uptake by DCs and subsequent migration from the skin to the regional lymph nodes (LNs) in mice. After subcutaneous injection of fluorescein 5-isothiocyanate (FITC)-labeled NPs or FITC-ovalbumin (OVA)-carrying NPs (FITC-OVA-NPs), DCs migrated from the skin to the LNs and maturated, resulting in the upregulation of the costimulatory molecules CD80 and CD86 and the chemokine receptor CCR7. However, the migrated DCs were not detected in the spleen. FITC-OVA-NPs were found to be taken up by skin-derived CD103(+) DCs, and the processed antigen peptides were cross-presented by the major histocompatibility complex (MHC) class I molecule of DCs. Furthermore, significant activation of antigen-specific CD8(+) T cells was observed in mice immunized with OVA-carrying NPs (OVA-NPs) but not with OVA alone or OVA with an aluminum adjuvant. The antigen-specific CD8(+) T cells were induced within 7 days after immunization with OVA-NPs. Thus, γ-PGA NPs carrying various antigens may have great potential as an antigen-delivery system and vaccine adjuvant in vivo.

  12. Enhancement of MHC-I antigen presentation via architectural control of pH-responsive, endosomolytic polymer nanoparticles.

    PubMed

    Wilson, John T; Postma, Almar; Keller, Salka; Convertine, Anthony J; Moad, Graeme; Rizzardo, Ezio; Meagher, Laurence; Chiefari, John; Stayton, Patrick S

    2015-03-01

    Protein-based vaccines offer a number of important advantages over organism-based vaccines but generally elicit poor CD8(+) T cell responses. We have previously demonstrated that pH-responsive, endosomolytic polymers can enhance protein antigen delivery to major histocompatibility complex class I (MHC-I) antigen presentation pathways thereby augmenting CD8(+) T cell responses following immunization. Here, we describe a new family of nanocarriers for protein antigen delivery assembled using architecturally distinct pH-responsive polymers. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize linear, hyperbranched, and core-crosslinked copolymers of 2-(N,N-diethylamino)ethyl methacrylate (DEAEMA) and butyl methacrylate (BMA) that were subsequently chain extended with a hydrophilic N,N-dimethylacrylamide (DMA) segment copolymerized with thiol-reactive pyridyl disulfide (PDS) groups. In aqueous solution, polymer chains assembled into 25 nm micellar nanoparticles and enabled efficient and reducible conjugation of a thiolated protein antigen, ovalbumin. Polymers demonstrated pH-dependent membrane-destabilizing activity in an erythrocyte lysis assay, with the hyperbranched and cross-linked polymer architectures exhibiting significantly higher hemolysis at pH ≤ 7.0 than the linear diblock. Antigen delivery with the hyperbranched and cross-linked polymer architecture enhanced in vitro MHC-I antigen presentation relative to free antigen, whereas the linear construct did not have a discernible effect. The hyperbranched system elicited a four- to fivefold increase in MHC-I presentation relative to the cross-linked architecture, demonstrating the superior capacity of the hyperbranched architecture in enhancing MHC-I presentation. This work demonstrates that the architecture of pH-responsive, endosomolytic polymers can have dramatic effects on intracellular antigen delivery, and offers a promising strategy for enhancing CD8(+) T cell

  13. Fcγ receptor antigen targeting potentiates cross-presentation by human blood and lymphoid tissue BDCA-3+ dendritic cells.

    PubMed

    Flinsenberg, Thijs W H; Compeer, Ewoud B; Koning, Dan; Klein, Mark; Amelung, Femke J; van Baarle, Debbie; Boelens, Jaap Jan; Boes, Marianne

    2012-12-20

    The reactivation of human cytomegalovirus (HCMV) poses a serious health threat to immune compromised individuals. As a treatment strategy, dendritic cell (DC) vaccination trials are ongoing. Recent work suggests that BDCA-3(+) (CD141(+)) subset DCs may be particularly effective in DC vaccination trials. BDCA-3(+) DCs had however been mostly characterized for their ability to cross-present antigen from necrotic cells. We here describe our study of human BDCA-3(+) DCs in elicitation of HCMV-specific CD8(+) T-cell clones. We show that Fcgamma-receptor (FcγR) antigen targeting facilitates antigen cross-presentation in several DC subsets, including BDCA-3(+) DCs. FcγR antigen targeting stimulates antigen uptake by BDCA-1(+) rather than BDCA-3(+) DCs. Conversely, BDCA-3(+) DCs and not BDCA-1(+) DCs show improved cross-presentation by FcγR targeting, as measured by induced release of IFNγ and TNF by antigen-specific CD8(+) T cells. FcγR-facilitated cross-presentation requires antigen processing in both an acidic endosomal compartment and by the proteasome, and did not induce substantial DC maturation. FcγRII is the most abundantly expressed FcγR on both BDCA-1(+) and BDCA-3(+) DCs. Furthermore we show that BDCA-3(+) DCs express relatively more stimulatory FcγRIIa than inhibitory FcγRIIb in comparison with BDCA-1(+) DCs. These studies support the exploration of FcγR antigen targeting to BDCA-3(+) DCs for human vaccination purposes.

  14. Ectopic expression of HLA-DO in mouse dendritic cells diminishes MHC class II antigen presentation.

    PubMed

    Fallas, Jennifer L; Tobin, Helen M; Lou, Olivia; Guo, Donglin; Sant'Angelo, Derek B; Denzin, Lisa K

    2004-08-01

    The MHC class II-like molecule HLA-DM (DM) (H-2M in mice) catalyzes the exchange of CLIP for antigenic peptides in the endosomes of APCs. HLA-DO (DO) (H-2O in mice) is another class II-like molecule that is expressed in B cells, but not in other APCs. Studies have shown that DO impairs or modifies the peptide exchange activity of DM. To further evaluate the role of DO in Ag processing and presentation, we generated transgenic mice that expressed the human HLA-DOA and HLA-DOB genes under the control of a dendritic cell (DC)-specific promoter. Our analyses of DCs from these mice showed that as DO levels increased, cell surface levels of A(b)-CLIP also increased while class II-peptide levels decreased. The presentation of some, but not all, exogenous Ags to T cells or T hybridomas was significantly inhibited by DO. Surprisingly, H-2M accumulated in DO-expressing DCs and B cells, suggesting that H-2O/DO prolongs the half-life of H-2M. Overall, our studies showed that DO expression impaired H-2M function, resulting in Ag-specific down-modulation of class II Ag processing and presentation.

  15. Deep reactive ion etching of auxetic structures: present capabilities and challenges

    NASA Astrophysics Data System (ADS)

    Muslija, Alban; Díaz Lantada, Andrés

    2014-08-01

    Auxetic materials (or metamaterials) have negative Poisson ratios (NPR) and display the unexpected properties of lateral expansion when stretched, and equal and opposing densification when compressed. Such auxetic materials are being used more frequently in the development of novel products, especially in the fields of intelligent expandable actuators, shape-morphing structures and minimally invasive implantable devices. Although several micromanufacturing technologies have already been applied to the development of auxetic materials and devices, additional precision is needed to take full advantage of their special mechanical properties. In this study, we present a very promising approach for the development of auxetic materials and devices based on the use of deep reactive ion etching (DRIE). The process stands out for its precision and its potential applications to mass production. To our knowledge, it represents the first time this technology has been applied to the manufacture of auxetic materials with nanometric details. We take into account the present capabilities and challenges linked to the use of DRIE in the development of auxetic materials and auxetic-based devices.

  16. Replication-deficient mutant Herpes Simplex Virus-1 targets professional antigen presenting cells and induces efficient CD4+ T helper responses.

    PubMed

    Fiorentini, Simona; Marconi, Peggy; Avolio, Manuela; Marini, Elena; Garrafa, Emirena; Caracciolo, Sonia; Rossi, Daniele; Bozac, Alexandra; Becker, Pablo D; Gentili, Francesca; Facchetti, Fabio; Guzman, Carlos A; Manservigi, Roberto; Caruso, Arnaldo

    2007-07-01

    Both neutralizing antibodies and cytotoxic T-cells are necessary to control a viral infection. However, vigorous T helper responses are essential for their elicitation and maintenance. Here we show that a recombinant replication-deficient Herpes Simplex Virus (HSV)-1 vector encoding the Human Immunodeficiency Virus (HIV)-1 matrix protein p17 (T0-p17) was capable of infecting professional antigen presenting cells (APCs) in vitro and in vivo. The injection of T0-p17 in the mouse dermis generated a strong p17-specific CD4+ T helper response preceding both p17-specific humoral and effector T cell responses. Moreover, we show that T0-p17 infection did not interfere with the endogenous processing of the transgene encoded antigen, since infected APCs were able to evoke a strong recall response in vitro. Our results demonstrate that replication-deficient HSV vectors can be appealing candidates for the development of vaccines able to trigger T helper responses.

  17. Rab22a controls MHC-I intracellular trafficking and antigen cross-presentation by dendritic cells.

    PubMed

    Cebrian, Ignacio; Croce, Cristina; Guerrero, Néstor A; Blanchard, Nicolas; Mayorga, Luis S

    2016-12-01

    Cross-presentation by MHC class I molecules allows the detection of exogenous antigens by CD8(+) T lymphocytes. This process is crucial to initiate cytotoxic immune responses against many pathogens (i.e., Toxoplasma gondii) and tumors. To achieve efficient cross-presentation, dendritic cells (DCs) have specialized endocytic pathways; however, the molecular effectors involved are poorly understood. In this work, we identify the small GTPase Rab22a as a key regulator of MHC-I trafficking and antigen cross-presentation by DCs. Our results demonstrate that Rab22a is recruited to DC endosomes and phagosomes, as well as to the vacuole containing T. gondii parasites. The silencing of Rab22a expression did not affect the uptake of exogenous antigens or parasite invasion, but it drastically reduced the intracellular pool and the recycling of MHC-I molecules. The knockdown of Rab22a also hampered the cross-presentation of soluble, particulate and T. gondii-associated antigens, but not the endogenous MHC-I antigen presentation through the classical secretory pathway. Our findings provide compelling evidence that Rab22a plays a central role in the MHC-I endocytic trafficking, which is crucial for efficient cross-presentation by DCs.

  18. Mannose receptor-mediated gene delivery into antigen presenting dendritic cells.

    PubMed

    Diebold, Sandra S; Plank, Christian; Cotten, Matt; Wagner, Ernst; Zenke, Martin

    2002-11-01

    Dendritic cells are professional antigen presenting cells and are unique in their ability to prime naïve T cells. Gene modification of dendritic cells is of particular interest for immunotherapy of diseases where the immune system has failed or is aberrantly regulated, such as in cancer or autoimmune disease, respectively. Dendritic cells abundantly express mannose receptor and mannose receptor-related receptors, and receptor-mediated gene transfer via mannose receptor offers a versatile tool for targeted gene delivery into these cells. Accordingly, mannose polyethylenimine DNA transfer complexes were generated and used for gene delivery into dendritic cells. Mannose receptor belongs to the group of scavenger receptors that allow dendritic cells to take up pathogenic material, which is directed for degradation and MHC class II presentation. Therefore, a limiting step of transgene expression by mannose receptor-mediated gene delivery is endosomal degradation of DNA. Several strategies have been explored to overcome this limitation including the addition of endosomolytic components to DNA transfer complexes like adenovirus particles and influenza peptides. Here, we review the current understanding of mannose receptor-mediated gene delivery into dendritic cells and discuss strategies to identify appropriate endosomolytic agents to improve DNA transfer efficacy.

  19. Dynamics of enhancers in myeloid antigen presenting cells upon LPS stimulation

    PubMed Central

    2014-01-01

    Background Recent studies have underscored the role of enhancers in defining cell type-specific transcriptomes. Cell type-specific enhancers are bound by combinations of shared and cell type-specific transcription factors (TFs). However, little is known about combinatorial binding of TFs to enhancers, dynamics of TF binding following stimulation, or the downstream effects on gene expression. Here, we address these questions in two types of myeloid antigen presenting cells (APCs), macrophages and dendritic cells (DCs), before and after stimulation with lipopolysaccharide (LPS), a potent stimulator of the innate immune response. Results We classified enhancers according to the combination of TFs binding them. There were significant correlations between the sets of TFs bound to enhancers prior to stimulation and expression changes of nearby genes after stimulation. Importantly, a set of enhancers pre-bound by PU.1, C/EBPβ, ATF3, IRF4, and JunB was strongly associated with induced genes and binding by stimulus-activated regulators. Our classification suggests that transient loss of ATF3 binding to a subset of these enhancers is important for regulation of early-induced genes. Changes in TF-enhancer binding after stimulation were correlated with binding by additional activated TFs and with the presence of proximally located enhancers. Conclusions The results presented in this study reveal the complexity and dynamics of TF- enhancer binding before and after stimulation in myeloid APCs. PMID:25560382

  20. The first step of peptide selection in antigen presentation by MHC class I molecules

    PubMed Central

    Garstka, Malgorzata A.; Fish, Alexander; Celie, Patrick H. N.; Joosten, Robbie P.; Janssen, George M. C.; Berlin, Ilana; Hoppes, Rieuwert; Stadnik, Magda; Janssen, Lennert; Ovaa, Huib; van Veelen, Peter A.; Perrakis, Anastassis; Neefjes, Jacques

    2015-01-01

    MHC class I molecules present a variable but limited repertoire of antigenic peptides for T-cell recognition. Understanding how peptide selection is achieved requires mechanistic insights into the interactions between the MHC I and candidate peptides. We find that, at first encounter, MHC I H-2Kb considers a wide range of peptides, including those with expanded N termini and unfitting anchor residues. Discrimination occurs in the second step, when noncanonical peptides dissociate with faster exchange rates. This second step exhibits remarkable temperature sensitivity, as illustrated by numerous noncanonical peptides presented by H-2Kb in cells cultured at 26 °C relative to 37 °C. Crystallographic analyses of H-2Kb–peptide complexes suggest that a conformational adaptation of H-2Kb drives the decisive step in peptide selection. We propose that MHC class I molecules consider initially a large peptide pool, subsequently refined by a temperature-sensitive induced-fit mechanism to retain the canonical peptide repertoire. PMID:25605945

  1. Cytosolic aminopeptidases influence MHC class I-mediated antigen presentation in an allele-dependent manner.

    PubMed

    Kim, Eunkyung; Kwak, Heechun; Ahn, Kwangseog

    2009-12-01

    Antigenic peptides presented by MHC class I molecules are generated mainly by the proteasome in the cytosol. Several cytosolic aminopeptidases further trim proteasomal products to form mature epitopes or individual amino acids. However, the distinct function of cytosolic aminopeptidases in MHC class I Ag processing remains to be elucidated. In this study, we show that cytosolic aminopeptidases differentially affect the cell surface expression of MHC class I molecules in an allele-dependent manner in human cells. In HeLa cells, knockdown of puromycin-sensitive aminopeptidase (PSA) by RNA interference inhibited optimal peptide loading of MHC class I molecules, and their cell surface expression was correspondingly reduced. In contrast, depletion of bleomycin hydrolase (BH) enhanced optimal peptide loading and cell surface expression of MHC class I molecules. We did not find evidence on the effect of leucine aminopeptidase knockdown on the MHC class I Ag presentation. Moreover, we demonstrated that PSA and BH influence the peptide loading and surface expression of MHC class I in an allele-specific manner. In the absence of either PSA or BH, the surface expression and peptide-dependent stability of HLA-A68 were reduced, whereas those of HLA-B15 were enhanced. The surface expression and peptide-dependent stability of HLA-A3 were enhanced by BH knockdown, although those of HLA-B8 were increased in PSA-depleted conditions.

  2. Antibody-functionalized peptidic membranes for neutralization of allogeneic skin antigen-presenting cells.

    PubMed

    Wen, Yi; Liu, Wen; Bagia, Christina; Zhang, Shaojuan; Bai, Mingfeng; Janjic, Jelena M; Giannoukakis, Nick; Gawalt, Ellen S; Meng, Wilson S

    2014-11-01

    We report herein application of an in situ material strategy to attenuate allograft T cell responses in a skin transplant mouse model. Functionalized peptidic membranes were used to impede trafficking of donor antigen-presenting cells (dAPCs) from skin allografts in recipient mice. Membranes formed by self-assembling peptides (SAPs) presenting antibodies were found to remain underneath grafted skins for up to 6 days. At the host-graft interface, dAPCs were targeted by using a monoclonal antibody that binds to a class II major histocompatibility complex (MHC) molecule (I-A(d)) expressed exclusively by donor cells. Using a novel cell labeling near-infrared nanoemulsion, we found more dAPCs remained in allografts treated with membranes loaded with anti-I-A(d) antibodies than without. In vitro, dAPCs released from skin explants were found adsorbed preferentially on anti-I-A(d) antibody-loaded membranes. Recipient T cells from these mice produced lower concentrations of interferon-gamma cultured ex vivo with donor cells. Taken together, the data indicate that the strategy has the potential to alter the natural course of rejection immune mechanisms in allogeneic transplant models. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. Human Leukocyte Antigen F Presents Peptides and Regulates Immunity through Interactions with NK Cell Receptors.

    PubMed

    Dulberger, Charles L; McMurtrey, Curtis P; Hölzemer, Angelique; Neu, Karlynn E; Liu, Victor; Steinbach, Adriana M; Garcia-Beltran, Wilfredo F; Sulak, Michael; Jabri, Bana; Lynch, Vincent J; Altfeld, Marcus; Hildebrand, William H; Adams, Erin J

    2017-06-20

    Evidence is mounting that the major histocompatibility complex (MHC) molecule HLA-F (human leukocyte antigen F) regulates the immune system in pregnancy, infection, and autoimmunity by signaling through NK cell receptors (NKRs). We present structural, biochemical, and evolutionary analyses demonstrating that HLA-F presents peptides of unconventional length dictated by a newly arisen mutation (R62W) that has produced an open-ended groove accommodating particularly long peptides. Compared to empty HLA-F open conformers (OCs), HLA-F tetramers bound with human-derived peptides differentially stained leukocytes, suggesting peptide-dependent engagement. Our in vitro studies confirm that NKRs differentiate between peptide-bound and peptide-free HLA-F. The complex structure of peptide-loaded β2m-HLA-F bound to the inhibitory LIR1 revealed similarities to high-affinity recognition of the viral MHC-I mimic UL18 and a docking strategy that relies on contacts with HLA-F as well as β2m, thus precluding binding to HLA-F OCs. These findings provide a biochemical framework to understand how HLA-F could regulate immunity via interactions with NKRs. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. The first step of peptide selection in antigen presentation by MHC class I molecules.

    PubMed

    Garstka, Malgorzata A; Fish, Alexander; Celie, Patrick H N; Joosten, Robbie P; Janssen, George M C; Berlin, Ilana; Hoppes, Rieuwert; Stadnik, Magda; Janssen, Lennert; Ovaa, Huib; van Veelen, Peter A; Perrakis, Anastassis; Neefjes, Jacques

    2015-02-03

    MHC class I molecules present a variable but limited repertoire of antigenic peptides for T-cell recognition. Understanding how peptide selection is achieved requires mechanistic insights into the interactions between the MHC I and candidate peptides. We find that, at first encounter, MHC I H-2K(b) considers a wide range of peptides, including those with expanded N termini and unfitting anchor residues. Discrimination occurs in the second step, when noncanonical peptides dissociate with faster exchange rates. This second step exhibits remarkable temperature sensitivity, as illustrated by numerous noncanonical peptides presented by H-2K(b) in cells cultured at 26 °C relative to 37 °C. Crystallographic analyses of H-2K(b)-peptide complexes suggest that a conformational adaptation of H-2K(b) drives the decisive step in peptide selection. We propose that MHC class I molecules consider initially a large peptide pool, subsequently refined by a temperature-sensitive induced-fit mechanism to retain the canonical peptide repertoire.

  5. Regulation of Hemichannels and Gap Junction Channels by Cytokines in Antigen-Presenting Cells

    PubMed Central

    Shoji, Kenji F.; Aguirre, Adam; Sáez, Juan C.

    2014-01-01

    Autocrine and paracrine signals coordinate responses of several cell types of the immune system that provide efficient protection against different challenges. Antigen-presenting cells (APCs) coordinate activation of this system via homocellular and heterocellular interactions. Cytokines constitute chemical intercellular signals among immune cells and might promote pro- or anti-inflammatory effects. During the last two decades, two membrane pathways for intercellular communication have been demonstrated in cells of the immune system. They are called hemichannels (HCs) and gap junction channels (GJCs) and provide new insights into the mechanisms of the orchestrated response of immune cells. GJCs and HCs are permeable to ions and small molecules, including signaling molecules. The direct intercellular transfer between contacting cells can be mediated by GJCs, whereas the release to or uptake from the extracellular milieu can be mediated by HCs. GJCs and HCs can be constituted by two protein families: connexins (Cxs) or pannexins (Panxs), which are present in almost all APCs, being Cx43 and Panx1 the most ubiquitous members of each protein family. In this review, we focus on the effects of different cytokines on the intercellular communication mediated by HCs and GJCs in APCs and their impact on purinergic signaling. PMID:25301274

  6. Presentation of antigen in immune complexes is boosted by soluble bacterial immunoglobulin binding proteins.

    PubMed

    Léonetti, M; Galon, J; Thai, R; Sautès-Fridman, C; Moine, G; Ménez, A

    1999-04-19

    Using a snake toxin as a proteic antigen (Ag), two murine toxin-specific monoclonal antibodies (mAbs), splenocytes, and two murine Ag-specific T cell hybridomas, we showed that soluble protein A (SpA) from Staphylococcus aureus and protein G from Streptococcus subspecies, two Ig binding proteins (IBPs), not only abolish the capacity of the mAbs to decrease Ag presentation but also increase Ag presentation 20-100-fold. Five lines of evidence suggest that this phenomenon results from binding of an IBP-Ab-Ag complex to B cells possessing IBP receptors. First, we showed that SpA is likely to boost presentation of a free mAb, suggesting that the IBP-boosted presentation of an Ag in an immune complex results from the binding of IBP to the mAb. Second, FACS analyses showed that an Ag-Ab complex is preferentially targeted by SpA to a subpopulation of splenocytes mainly composed of B cells. Third, SpA-dependent boosted presentation of an Ag-Ab complex is further enhanced when splenocytes are enriched in cells containing SpA receptors. Fourth, the boosting effect largely diminishes when splenocytes are depleted of cells containing SpA receptors. Fifth, the boosting effect occurs only when IBP simultaneously contains a Fab and an Fc binding site. Altogether, our data suggest that soluble IBPs can bridge immune complexes to APCs containing IBP receptors, raising the possibility that during an infection process by bacteria secreting these IBPs, Ag-specific T cells may activate IBP receptor-containing B cells by a mechanism of intermolecular help, thus leading to a nonspecific immune response.

  7. CD1d-mediated presentation of endogenous lipid antigens by adipocytes requires microsomal triglyceride transfer protein.

    PubMed

    Rakhshandehroo, Maryam; Gijzel, Sanne M W; Siersbæk, Rasmus; Broekema, Marjoleine F; de Haar, Colin; Schipper, Henk S; Boes, Marianne; Mandrup, Susanne; Kalkhoven, Eric

    2014-08-08

    Obesity-induced adipose tissue (AT) dysfunction results in a chronic low-grade inflammation that predisposes to the development of insulin resistance and type 2 diabetes. During the development of obesity, the AT-resident immune cell profile alters to create a pro-inflammatory state. Very recently, CD1d-restricted invariant (i) natural killer T (NKT) cells, a unique subset of lymphocytes that are reactive to so called lipid antigens, were implicated in AT homeostasis. Interestingly, recent data also suggest that human and mouse adipocytes can present such lipid antigens to iNKT cells in a CD1d-dependent fashion, but little is known about the lipid antigen presentation machinery in adipocytes. Here we show that CD1d, as well as the lipid antigen loading machinery genes pro-saposin (Psap), Niemann Pick type C2 (Npc2), α-galactosidase (Gla), are up-regulated in early adipogenesis, and are transcriptionally controlled by CCAAT/enhancer-binding protein (C/EBP)-β and -δ. Moreover, adipocyte-induced Th1 and Th2 cytokine release by iNKT cells also occurred in the absence of exogenous ligands, suggesting the display of endogenous lipid antigen-D1d complexes by 3T3-L1 adipocytes. Furthermore, we identified microsomal triglyceride transfer protein, which we show is also under the transcriptional regulation of C/EBPβ and -δ, as a novel player in the presentation of endogenous lipid antigens by adipocytes. Overall, our findings indicate that adipocytes can function as non-professional lipid antigen presenting cells, which may present an important aspect of adipocyte-immune cell communication in the regulation of whole body energy metabolism and immune homeostasis.

  8. CD1d-mediated Presentation of Endogenous Lipid Antigens by Adipocytes Requires Microsomal Triglyceride Transfer Protein*

    PubMed Central

    Rakhshandehroo, Maryam; Gijzel, Sanne M. W.; Siersbæk, Rasmus; Broekema, Marjoleine F.; de Haar, Colin; Schipper, Henk S.; Boes, Marianne; Mandrup, Susanne; Kalkhoven, Eric

    2014-01-01

    Obesity-induced adipose tissue (AT) dysfunction results in a chronic low-grade inflammation that predisposes to the development of insulin resistance and type 2 diabetes. During the development of obesity, the AT-resident immune cell profile alters to create a pro-inflammatory state. Very recently, CD1d-restricted invariant (i) natural killer T (NKT) cells, a unique subset of lymphocytes that are reactive to so called lipid antigens, were implicated in AT homeostasis. Interestingly, recent data also suggest that human and mouse adipocytes can present such lipid antigens to iNKT cells in a CD1d-dependent fashion, but little is known about the lipid antigen presentation machinery in adipocytes. Here we show that CD1d, as well as the lipid antigen loading machinery genes pro-saposin (Psap), Niemann Pick type C2 (Npc2), α-galactosidase (Gla), are up-regulated in early adipogenesis, and are transcriptionally controlled by CCAAT/enhancer-binding protein (C/EBP)-β and -δ. Moreover, adipocyte-induced Th1 and Th2 cytokine release by iNKT cells also occurred in the absence of exogenous ligands, suggesting the display of endogenous lipid antigen-D1d complexes by 3T3-L1 adipocytes. Furthermore, we identified microsomal triglyceride transfer protein, which we show is also under the transcriptional regulation of C/EBPβ and –δ, as a novel player in the presentation of endogenous lipid antigens by adipocytes. Overall, our findings indicate that adipocytes can function as non-professional lipid antigen presenting cells, which may present an important aspect of adipocyte-immune cell communication in the regulation of whole body energy metabolism and immune homeostasis. PMID:24966328

  9. Fast whole-brain optical tomography capable of automated slice-collection (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Yuan, Jing; Jiang, Tao; Deng, Lei; Long, Beng; Peng, Jie; Luo, Qingming; Gong, Hui

    2016-03-01

    Acquiring brain-wide composite information of neuroanatomical and molecular phenotyping is crucial to understand brain functions. However, current whole-brain imaging methods based on mechnical sectioning haven't achieved brain-wide acquisition of both neuroanatomical and molecular phenotyping due to the lack of appropriate whole-brain immunostaining of embedded samples. Here, we present a novel strategy of acquiring brain-wide structural and molecular maps in the same brain, combining whole-brain imaging and subsequent immunostaining of automated-collected slices. We developed a whole-brain imaging system capable of automatically imaging and then collecting imaged tissue slices in order. The system contains three parts: structured illumination microscopy for high-throughput optical sectioning, vibratome for high-precision sectioning and slice-collection device for automated collecting of tissue slices. Through our system, we could acquire a whole-brain dataset of agarose-embedded mouse brain at lateral resolution of 0.33 µm with z-interval sampling of 100 µm in 9 h, and automatically collect the imaged slices in sequence. Subsequently, we performed immunohistochemistry of the collected slices in the routine way. We acquired mouse whole-brain imaging datasets of multiple specific types of neurons, proteins and gene expression profiles. We believe our method could accelerate systematic analysis of brain anatomical structure with specific proteins or genes expression information and understanding how the brain processes information and generates behavior.

  10. The Biology and Underlying Mechanisms of Cross-Presentation of Exogenous Antigens on MHC-I Molecules.

    PubMed

    Cruz, Freidrich M; Colbert, Jeff D; Merino, Elena; Kriegsman, Barry A; Rock, Kenneth L

    2017-04-26

    To monitor the health of cells, the immune system tasks antigen-presenting cells with gathering antigens from other cells and bringing them to CD8 T cells in the form of peptides bound to MHC-I molecules. Most cells would be unable to perform this function because they use their MHC-I molecules to exclusively present peptides derived from the cell's own proteins. However, the immune system evolved mechanisms for dendritic cells and some other phagocytes to sample and present antigens from the extracellular milieu on MHC-I through a process called cross-presentation. How this important task is accomplished, its role in health and disease, and its potential for exploitation are the subject of this review.

  11. Antigen Presentation by Dendritic Cells after Immunization with DNA Encoding a Major Histocompatibility Complex Class II–restricted Viral Epitope

    PubMed Central

    Casares, Sofia; Inaba, Kayo; Brumeanu, Teodor-Doru; Steinman, Ralph M.; Bona, Constantin A.

    1997-01-01

    Intramuscular and intracutaneous immunization with naked DNA can vaccinate animals to the encoded proteins, but the underlying mechanisms of antigen presentation are unclear. We used DNA that encodes an A/PR/8/34 influenza peptide for CD4 T cells and that elicits protective antiviral immunity. DNA-transfected, cultured muscle cells released the influenza polypeptide, which then could be presented on the major histocompatibility complex class II molecules of dendritic cells. When DNA was injected into muscles or skin, and antigen-presenting cells were isolated from either the draining lymph nodes or the skin, dendritic, but not B, cells presented antigen to T cells and carried plasmid DNA. We suggest that the uptake of DNA and/or the protein expressed by dendritic cells triggers immune responses to DNA vaccines. PMID:9348305

  12. B cell-mediated antigen presentation is required for the pathogenesis of acute cardiac allograft rejection.

    PubMed

    Noorchashm, Hooman; Reed, Amy J; Rostami, Susan Y; Mozaffari, Raha; Zekavat, Ghazal; Koeberlein, Brigitte; Caton, Andrew J; Naji, Ali

    2006-12-01

    Acute allograft rejection requires the activation of alloreactive CD4 T cells. Despite the capacity of B cells to act as potent APCs capable of activating CD4 T cells in vivo, their role in the progression of acute allograft rejection was unclear. To determine the contribution of B cell APC function in alloimmunity, we engineered mice with a targeted deficiency of MHC class II-mediated Ag presentation confined to the B cell compartment. Cardiac allograft survival was markedly prolonged in these mice as compared to control counterparts (median survival time, >70 vs 9.5 days). Mechanistically, deficient B cell-mediated Ag presentation disrupted both alloantibody production and the progression of CD4 T cell activation following heart transplantation. These findings demonstrate that indirect alloantigen presentation by recipients' B cells plays an important role in the efficient progression of acute vascularized allograft rejection.

  13. Role of Antigen-Presenting Cells in Mediating Tolerance and Autoimmunity

    PubMed Central

    Garza, Kristine M.; Chan, Steven M.; Suri, Rakesh; Nguyen, Linh T.; Odermatt, Bernhard; Schoenberger, Stephen P.; Ohashi, Pamela S.

    2000-01-01

    The mechanisms that determine whether receptor stimulation leads to lymphocyte tolerance versus activation remain poorly understood. We have used rat insulin promoter (RIP)-gp/P14 double-transgenic mice expressing the lymphocytic choriomeningitis virus (LCMV) glycoprotein (gp) on pancreatic β-islet cells together with T cells expressing an LCMV-gp–specific T cell receptor to assess the requirements for the induction of autoimmunity. Our studies have shown that administration of the gp peptide gp33 leads to the activation of P14-transgenic T cells, as measured by the upregulation of activation markers and the induction of effector cytotoxic activity. This treatment also leads to expansion and deletion of P14 T cells. Despite the induction of cytotoxic T lymphocyte activity, peptide administration is not sufficient to induce diabetes. However, the administration of gp peptide together with an activating anti-CD40 antibody rapidly induces diabetes. These findings suggest that the induction of tolerance versus autoimmunity is determined by resting versus activated antigen-presenting cells. PMID:10839816

  14. B7-H1-expressing antigen-presenting cells mediate polarization of protumorigenic Th22 subsets.

    PubMed

    Kuang, Dong-Ming; Xiao, Xiao; Zhao, Qiyi; Chen, Min-Min; Li, Xue-Feng; Liu, Rui-Xian; Wei, Yuan; Ouyang, Fang-Zhu; Chen, Dong-Ping; Wu, Yan; Lao, Xiang-Ming; Deng, Hong; Zheng, Limin

    2014-10-01

    Classical IL-22-producing T helper cells (Th22 cells) mediate inflammatory responses independently of IFN-γ and IL-17; however, nonclassical Th22 cells have been recently identified and coexpress IFN-γ and/or IL-17 along with IL-22. Little is known about how classical and nonclassical Th22 subsets in human diseases are regulated. Here, we used samples of human blood, normal and peritumoral liver, and hepatocellular carcinoma (HCC) to delineate the phenotype, distribution, generation, and functional relevance of various Th22 subsets. Three nonclassical Th22 subsets constituted the majority of all Th22 cells in human liver and HCC tissues, although the classical Th22 subset was predominant in blood. Monocytes activated by TLR2 and TLR4 agonists served as the antigen-presenting cells (APCs) that most efficiently triggered the expansion of nonclassical Th22 subsets from memory T cells and classical Th22 subsets from naive T cells. Moreover, B7-H1-expressing monocytes skewed Th22 polarization away from IFN-γ and toward IL-17 through interaction with programmed death 1 (PD-1), an effect that can create favorable conditions for in vivo aggressive cancer growth and angiogenesis. Our results provide insight into the selective modulation of Th22 subsets and suggest that strategies to influence functional activities of inflammatory cells may benefit anticancer therapy.

  15. Herpes virus oncolytic therapy reverses tumor immune dysfunction and facilitates tumor antigen presentation.

    PubMed

    Benencia, Fabian; Courrèges, Maria C; Fraser, Nigel W; Coukos, George

    2008-08-01

    We have previously shown that intratumor administration of HSV-1716 (an ICP34.5 null mutant) resulted in significant reduction of tumor growth and a significant survival advantage in a murine model of ovarian cancer. Herewith we report that oncolytic HSV-1716 generates vaccination effects in the same model. Upon HSV-1716 infection, mouse ovarian tumor cells showed high levels of expression viral glycoproteins B and D and were highly phagocyted by dendritic cells (DCs). Interestingly, increased phagocytosis of tumor-infected cells by DCs was impaired by heparin, and anti-HSV glycoproteins B and D, indicating that viral infection enhances adhesive interactions between DCs and tumor apoptotic bodies. Moreover, HSV-1716 infected cells expressed high levels of heat shock proteins 70 and GRP94, molecules that have been reported to induce maturation of DCs, increase cross-presentation of antigens and promote antitumor immune response. After phagocytosis of tumor-infected cells, DCs acquired a mature status in vitro and in vivo, upregulated the expression of costimulatory molecule and increased migration towards MIP-3beta. Furthermore, HSV-1716 oncolytic treatment markedly reduced vascular endothelial growth factor (VEGF) levels in tumor-bearing animals thus abrogating tumor immunosuppressive milieu. These mechanisms may account for the highly enhanced antitumoral immune responses observed in HSV-1716 treated animals. Oncolytic treatment induced a significantly higher frequency of tumor-reactive IFNgamma producing cells, and induced a robust tumor infiltration by T cells. These results indicate that oncolytic therapy with HSV-1716 facilitates antitumor immune responses.

  16. Grassystatins A–C from Marine Cyanobacteria, Potent Cathepsin E Inhibitors that Reduce Antigen Presentation

    PubMed Central

    Kwan, Jason C.; Eksioglu, Erika A.; Liu, Chen; Paul, Valerie J.; Luesch, Hendrik

    2009-01-01

    In our efforts to explore marine cyanobacteria as a source of novel bioactive compounds we discovered a statine unit-containing linear decadepsipeptide, grassystatin A (1), which we screened against a diverse set of 59 proteases. We describe the structure determination of 1 and two natural analogs, grassystatins B (2) and C (3), using NMR, MS, and chiral HPLC techniques. Compound 1 selectively inhibited cathepsins D and E with IC50s of 26.5 nM and 886 pM, respectively. Compound 2 showed similar potency and selectivity against cathepsins D and E (IC50s 7.27 nM and 354 pM, respectively), whereas the truncated peptide analog grassystatin C (3), which consists of two fewer residues than 1 and 2, was less potent against both but still selective for cathepsin E. The selectivity of compounds 1–3 for cathepsin E over D (20- to 38-fold) suggests that these natural products may be useful tools to probe cathepsin E function. We investigated the structural basis of this selectivity using molecular docking. We also show that 1 can reduce antigen presentation by dendritic cells, a process thought to rely on cathepsin E. PMID:19715320

  17. HLA Class II Antigen Presentation in Prostate Cancer Cells: A Novel Approach to Prostate Tumor Immunotherapy.

    PubMed

    Doonan, Bently Patrick; Haque, Azizul

    2010-01-01

    Prostate cancer is a deadly disease that is in drastic need of new treatment strategies for late stage and metastatic prostate cancer. Immunotherapy has emerged as a viable option to fill this void. Clinical trials have been conducted that induce tumor clearance through cytotoxic T lymphocyte (CTL) activation, these studies have had mixed outcomes with the overlying problem being the lack of a complete immune response with sustained killing and the formation of tumor specific memory cells. To overcome this, we have outlined the need for activating the HLA class II pathway in inducing a sustained CD8+ T cell response and the development of effective memory. We have also discussed the ability of prostate cancer cells to express stable HLA class II molecules that can be manipulated for tumor antigen (Ag) processing and presentation. This review also sets to outline new directions that exist for the use of class II-restricted Ags/peptides in devising cancer vaccines as well as combined chemoimmunotherapy. A better understanding of these concepts will improve future cancer vaccine studies and further the field of cancer immunobiology.

  18. Nanoparticle-Based Manipulation of Antigen-Presenting Cells for Cancer Immunotherapy.

    PubMed

    Fang, Ronnie H; Kroll, Ashley V; Zhang, Liangfang

    2015-11-04

    Immunotherapeutic approaches for treating cancer overall have been receiving a considerable amount of interest due to the recent approval of several clinical formulations. Among the different modalities, anticancer vaccination acts by training the body to endogenously generate a response against tumor cells. However, despite the large amount of work that has gone into the development of such vaccines, the near absence of clinically approved formulations highlights the many challenges facing those working in the field. The generation of potent endogenous anticancer responses poses unique challenges due to the similarity between cancer cells and normal, healthy cells. As researchers continue to tackle the limited efficacy of vaccine formulations, fresh and novel approaches are being sought after to address many of the underlying problems. Here the application of nanoparticle technology towards the development of anticancer vaccines is discussed. Specifically, there is a focus on the benefits of using such strategies to manipulate antigen presenting cells (APCs), which are essential to the vaccination process, and how nanoparticle-based platforms can be rationally engineered to elicit appropriate downstream immune responses.

  19. HIV-1 Trans Infection of CD4+ T Cells by Professional Antigen Presenting Cells

    PubMed Central

    Rinaldo, Charles R.

    2013-01-01

    Since the 1990s we have known of the fascinating ability of a complex set of professional antigen presenting cells (APCs; dendritic cells, monocytes/macrophages, and B lymphocytes) to mediate HIV-1 trans infection of CD4+ T cells. This results in a burst of virus replication in the T cells that is much greater than that resulting from direct, cis infection of either APC or T cells, or trans infection between T cells. Such APC-to-T cell trans infection first involves a complex set of virus subtype, attachment, entry, and replication patterns that have many similarities among APC, as well as distinct differences related to virus receptors, intracellular trafficking, and productive and nonproductive replication pathways. The end result is that HIV-1 can sequester within the APC for several days and be transmitted via membrane extensions intracellularly and extracellularly to T cells across the virologic synapse. Virus replication requires activated T cells that can develop concurrently with the events of virus transmission. Further research is essential to fill the many gaps in our understanding of these trans infection processes and their role in natural HIV-1 infection. PMID:24278768

  20. The Transcription Factor NFAT Exhibits Signal Memory during Serial T Cell Interactions with Antigen Presenting Cells

    PubMed Central

    Marangoni, Francesco; Murooka, Thomas T.; Manzo, Teresa; Kim, Edward Y.; Carrizosa, Esteban; Elpek, Natalie M.; Mempel, Thorsten R.

    2012-01-01

    Summary Interactions with antigen-presenting cells (APCs) interrupt T cell migration through tissues and trigger signaling pathways that converge on the activation of transcriptional regulators, including NFAT, which control T cell function and differentiation. Both stable and unstable modes of cognate T cell-APC interactions have been observed in vivo, but the functional significance of unstable, serial contacts has remained unclear. Here we used multiphoton intravital microscopy in lymph nodes and tumors to show that while NFAT nuclear import was fast (t1/2 max~1min), nuclear export was slow (t1/2~20min) in T cells. During delayed export, nuclear NFAT constituted a short-term imprint of transient TCR signals and remained transcriptionally active for the T cell tolerance gene Egr2, but not for the effector gene Ifng, which required continuous TCR triggering for expression. This provides a potential mechanistic basis for the observation that a predominance of unstable APC interactions correlates with the induction of T cell tolerance. PMID:23313588

  1. Therapeutic antiviral T cells noncytopathically clear persistently infected microglia after conversion into antigen-presenting cells

    PubMed Central

    Herz, Jasmin; Johnson, Kory R.

    2015-01-01

    Several viruses can infect the mammalian nervous system and induce neurological dysfunction. Adoptive immunotherapy is an approach that involves administration of antiviral T cells and has shown promise in clinical studies for the treatment of peripheral virus infections in humans such as cytomegalovirus (CMV), Epstein-Barr virus (EBV), and adenovirus, among others. In contrast, clearance of neurotropic infections is particularly challenging because the central nervous system (CNS) is relatively intolerant of immunopathological reactions. Therefore, it is essential to develop and mechanistically understand therapies that noncytopathically eradicate pathogens from the CNS. Here, we used mice persistently infected from birth with lymphocytic choriomeningitis virus (LCMV) to demonstrate that therapeutic antiviral T cells can completely purge the persistently infected brain without causing blood–brain barrier breakdown or tissue damage. Mechanistically, this is accomplished through a tailored release of chemoattractants that recruit antiviral T cells, but few pathogenic innate immune cells such as neutrophils and inflammatory monocytes. Upon arrival, T cells enlisted the support of nearly all brain-resident myeloid cells (microglia) by inducing proliferation and converting them into CD11c+ antigen-presenting cells (APCs). Two-photon imaging experiments revealed that antiviral CD8+ and CD4+ T cells interacted directly with CD11c+ microglia and induced STAT1 signaling but did not initiate programmed cell death. We propose that noncytopathic CNS viral clearance can be achieved by therapeutic antiviral T cells reliant on restricted chemoattractant production and interactions with apoptosis-resistant microglia. PMID:26122661

  2. Antigen presenting cell abnormalities in the Cln3(-/-) mouse model of juvenile neuronal ceroid lipofuscinosis.

    PubMed

    Hersrud, Samantha L; Kovács, Attila D; Pearce, David A

    2016-07-01

    Mutations of the CLN3 gene lead to juvenile neuronal ceroid lipofuscinosis (JNCL), an autosomal recessive lysosomal storage disorder that causes progressive neurodegeneration in children and adolescents. There is evidence of immune system involvement in pathology that has been only minimally investigated. We characterized bone marrow stem cell-derived antigen presenting cells (APCs), peritoneal macrophages, and leukocytes from spleen and blood, harvested from the Cln3(-/-) mouse model of JNCL. We detected dramatically elevated CD11c surface levels and increased total CD11c protein in Cln3(-/-) cell samples compared to wild type. This phenotype was specific to APCs and also to a loss of CLN3, as surface levels did not differ from wild type in other leukocyte subtypes nor in cells from two other NCL mouse models. Subcellularly, CD11c was localized to lipid rafts, indicating that perturbation of surface levels is attributable to derangement of raft dynamics, which has previously been shown in Cln3 mutant cells. Interrogation of APC function revealed that Cln3(-/-) cells have increased adhesiveness to CD11c ligands as well as an abnormal secretory pattern that closely mimics what has been previously reported for Cln3 mutant microglia. Our results show that CLN3 deficiency alters APCs, which can be a major contributor to the autoimmune response in JNCL. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Zerumbone modulates CD1d expression and lipid antigen presentation pathway in breast cancer cells.

    PubMed

    Shyanti, Ritis K; Sehrawat, Anuradha; Singh, Shivendra V; Mishra, J P N; Singh, Rana P

    2017-10-01

    Natural Killer T (NKT) cells based cancer immunotherapy is an evolving area of cancer therapy, but tumors escape from this treatment modality by altering CD1d expression and its antigen presentation pathway. Here, we have studied the relation of CD1d expression in various breast cancer cell lines to their viability and progression. We observed a novel phenomenon that CD1d expression level increases with the progressive stage of the cancer. A small molecule, zerumbone (ZER) caused down-regulation of CD1d that was accompanied by breast cancer cell growth in vitro. The growth inhibitory effect of ZER against breast cancer cells was augmented by treatment with anti-CD1d mAb. This effect was mediated by G1-phase cell cycle arrest and apoptosis induction coupled with an increase in mitochondrial membrane depolarization. CD1d expression and cell proliferation were inhibited by both CD1d siRNA and ZER. The α-galactosylceramide, a ligand for CD1d, showed increased CD1d expression as well as cell proliferation which was opposite to the effects of ZER. This study shows that, CD1d overexpression is associated with the progressive stages of breast cancer and ZER could be an adjuvant to potentiate cancer immunotherapy. Copyright © 2017. Published by Elsevier Ltd.

  4. Engineered Hydrogen-Bonded Glycopolymer Capsules and Their Interactions with Antigen Presenting Cells.

    PubMed

    Kempe, Kristian; Xiang, Sue D; Wilson, Paul; Rahim, Md Arifur; Ju, Yi; Whittaker, Michael R; Haddleton, David M; Plebanski, Magdalena; Caruso, Frank; Davis, Thomas P

    2017-02-22

    Hollow glycopolymer microcapsules were fabricated by hydrogen-bonded layer-by-layer (LbL) assembly, and their interactions with a set of antigen presenting cells (APCs), including dendritic cells (DCs), macrophages (MACs), and myeloid derived suppressor cells (MDSCs), were investigated. The glycopolymers were obtained by cascade postpolymerization modifications of poly(oligo(2-ethyl-2-oxazoline methacrylate)-stat-glycidyl methacrylate) involving the modification of the glycidyl groups with propargylamine and the subsequent attachment of mannose azide by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). Multilayer assembly of the hydrogen-bonding pair (glycopolymer/poly(methacrylic acid) (PMA)) onto planar and particulate supports (SiO2 particles, d = 1.16 μm) yielded stable glycopolymer films upon cross-linking by CuAAC. The silica (SiO2) particle templates were removed yielding hollow monodisperse capsules, as demonstrated by fluorescence and scanning electron microscopy. Cellular uptake studies using flow cytometry revealed the preferential uptake of the capsules by DCs when compared to MACs or MDSCs. Mannosylated capsules showed a cytokine independent cis-upregulation of CD80 specifically on DCs and a trans-downregulation of PDL-1 on MDSCs. Thus, the glycopolymer capsules may have potential as vaccine carriers, as they are able to upregulate costimulatory molecules for immune cell stimulation on DCs and at the same time downregulate immune inhibitory receptors on suppressor APC such as MDSCs.

  5. MHC class I antigen presentation and implications for developing a new generation of therapeutic vaccines.

    PubMed

    Comber, Joseph D; Philip, Ramila

    2014-05-01

    Major histocompatibility complex class I (MHC-I) presented peptide epitopes provide a 'window' into the changes occurring in a cell. Conventionally, these peptides are generated by proteolysis of endogenously synthesized proteins in the cytosol, loaded onto MHC-I molecules, and presented on the cell surface for surveillance by CD8(+) T cells. MHC-I restricted processing and presentation alerts the immune system to any infectious or tumorigenic processes unfolding intracellularly and provides potential targets for a cytotoxic T cell response. Therefore, therapeutic vaccines based on MHC-I presented peptide epitopes could, theoretically, induce CD8(+) T cell responses that have tangible clinical impacts on tumor eradication and patient survival. Three major methods have been used to identify MHC-I restricted epitopes for inclusion in peptide-based vaccines for cancer: genetic, motif prediction and, more recently, immunoproteomic analysis. Although the first two methods are capable of identifying T cell stimulatory epitopes, these have significant disadvantages and may not accurately represent epitopes presented by a tumor cell. In contrast, immunoproteomic methods can overcome these disadvantages and identify naturally processed and presented tumor associated epitopes that induce more clinically relevant tumor specific cytotoxic T cell responses. In this review, we discuss the importance of using the naturally presented MHC-I peptide repertoire in formulating peptide vaccines, the recent application of peptide-based vaccines in a variety of cancers, and highlight the pros and cons of the current state of peptide vaccines.

  6. MHC class I antigen presentation and implications for developing a new generation of therapeutic vaccines

    PubMed Central

    Comber, Joseph D.

    2014-01-01

    Major histocompatibility complex class I (MHC-I) presented peptide epitopes provide a ‘window’ into the changes occurring in a cell. Conventionally, these peptides are generated by proteolysis of endogenously synthesized proteins in the cytosol, loaded onto MHC-I molecules, and presented on the cell surface for surveillance by CD8+ T cells. MHC-I restricted processing and presentation alerts the immune system to any infectious or tumorigenic processes unfolding intracellularly and provides potential targets for a cytotoxic T cell response. Therefore, therapeutic vaccines based on MHC-I presented peptide epitopes could, theoretically, induce CD8+ T cell responses that have tangible clinical impacts on tumor eradication and patient survival. Three major methods have been used to identify MHC-I restricted epitopes for inclusion in peptide-based vaccines for cancer: genetic, motif prediction and, more recently, immunoproteomic analysis. Although the first two methods are capable of identifying T cell stimulatory epitopes, these have significant disadvantages and may not accurately represent epitopes presented by a tumor cell. In contrast, immunoproteomic methods can overcome these disadvantages and identify naturally processed and presented tumor associated epitopes that induce more clinically relevant tumor specific cytotoxic T cell responses. In this review, we discuss the importance of using the naturally presented MHC-I peptide repertoire in formulating peptide vaccines, the recent application of peptide-based vaccines in a variety of cancers, and highlight the pros and cons of the current state of peptide vaccines. PMID:24790732

  7. Ligation of the cell surface receptor, CD46, alters T cell polarity and response to antigen presentation

    PubMed Central

    Oliaro, Jane; Pasam, Anupama; Waterhouse, Nigel J.; Browne, Kylie A.; Ludford-Menting, Mandy J.; Trapani, Joseph A.; Russell, Sarah M.

    2006-01-01

    Lymphocyte function in vivo is dictated by multiple external cues, but the integration of different signals is not well understood. Here, we show that competition for the axis of polarization dictates functional outcomes. We investigated the effect of ligation of the immunoregulatory cell surface receptor, CD46, on lymphocyte polarity during antigen presentation and cytotoxic effector function. Ligation of CD46 on human T cells prevented recruitment of the microtubule organizing center, CD3, and perforin to the interface with the antigen-presenting cell and caused a reduction in IFN-γ production. In human NK cells, similar changes in polarity induced by CD46 ligation inhibited the recruitment of the microtubule organizing center and perforin to the interface with target cells and correlated with reduced killing. These data indicate that external signals can alter lymphocyte polarization toward antigen-presenting cells or target cells, inhibiting lymphocyte function. PMID:17116876

  8. Ligation of the cell surface receptor, CD46, alters T cell polarity and response to antigen presentation.

    PubMed

    Oliaro, Jane; Pasam, Anupama; Waterhouse, Nigel J; Browne, Kylie A; Ludford-Menting, Mandy J; Trapani, Joseph A; Russell, Sarah M

    2006-12-05

    Lymphocyte function in vivo is dictated by multiple external cues, but the integration of different signals is not well understood. Here, we show that competition for the axis of polarization dictates functional outcomes. We investigated the effect of ligation of the immunoregulatory cell surface receptor, CD46, on lymphocyte polarity during antigen presentation and cytotoxic effector function. Ligation of CD46 on human T cells prevented recruitment of the microtubule organizing center, CD3, and perforin to the interface with the antigen-presenting cell and caused a reduction in IFN-gamma production. In human NK cells, similar changes in polarity induced by CD46 ligation inhibited the recruitment of the microtubule organizing center and perforin to the interface with target cells and correlated with reduced killing. These data indicate that external signals can alter lymphocyte polarization toward antigen-presenting cells or target cells, inhibiting lymphocyte function.

  9. Effects of messenger RNA structure and other translational control mechanisms on major histocompatibility complex-I mediated antigen presentation

    PubMed Central

    Murat, Pierre; Tellam, Judy

    2015-01-01

    Effective T-cell surveillance of antigen-presenting cells is dependent on the expression of an array of antigenic peptides bound to major histocompatibility complex (MHC) class I (MHC-I) or class II (MHC-II) molecules. Pathogens co-evolving with their hosts exploit crucial translational regulatory mechanisms in order to evade host immune recognition and thereby sustain their infection. Evasion strategies that downregulate viral protein synthesis and thereby restrict antigen presentation to cytotoxic T-cells through the endogenous MHC-I pathway have been implicated in the pathogenesis of viral-associated malignancies. An understanding of the mechanisms by which messenger RNA (mRNA) structure modulates both viral mRNA translation and the antigen processing machinery to escape immune surveillance, will stimulate the development of alternative therapeutic strategies focused on RNA-directed drugs designed to enhance immune responses against infected cells. In this review, we discuss regulatory aspects of the MHC-I pathway and summarize current knowledge of the role attributed by mRNA structure and other translational regulatory mechanisms in immune evasion. In particular we highlight the impact of recently identified G-quadruplex structures within virally encoded transcripts as unique regulatory signals for translational control and antigen presentation. WIREs RNA 2015, 6:157–171. doi: 10.1002/wrna.1262 PMID:25264139

  10. Effects of messenger RNA structure and other translational control mechanisms on major histocompatibility complex-I mediated antigen presentation.

    PubMed

    Murat, Pierre; Tellam, Judy

    2015-01-01

    Effective T-cell surveillance of antigen-presenting cells is dependent on the expression of an array of antigenic peptides bound to major histocompatibility complex (MHC) class I (MHC-I) or class II (MHC-II) molecules. Pathogens co-evolving with their hosts exploit crucial translational regulatory mechanisms in order to evade host immune recognition and thereby sustain their infection. Evasion strategies that downregulate viral protein synthesis and thereby restrict antigen presentation to cytotoxic T-cells through the endogenous MHC-I pathway have been implicated in the pathogenesis of viral-associated malignancies. An understanding of the mechanisms by which messenger RNA (mRNA) structure modulates both viral mRNA translation and the antigen processing machinery to escape immune surveillance, will stimulate the development of alternative therapeutic strategies focused on RNA-directed drugs designed to enhance immune responses against infected cells. In this review, we discuss regulatory aspects of the MHC-I pathway and summarize current knowledge of the role attributed by mRNA structure and other translational regulatory mechanisms in immune evasion. In particular we highlight the impact of recently identified G-quadruplex structures within virally encoded transcripts as unique regulatory signals for translational control and antigen presentation.

  11. Structural reorganization of the antigen-binding groove of human CD1b for presentation of mycobacterial sulfoglycolipids

    PubMed Central

    Garcia-Alles, Luis F.; Collmann, Anthony; Versluis, Cees; Lindner, Buko; Guiard, Julie; Maveyraud, Laurent; Huc, Emilie; Im, Jin S.; Sansano, Sebastiano; Brando, Thérèse; Julien, Sylviane; Prandi, Jacques; Gilleron, Martine; Porcelli, Steven A.; de la Salle, Henri; Heck, Albert J. R.; Mori, Lucia; Puzo, Germain; Mourey, Lionel; De Libero, Gennaro

    2011-01-01

    The mechanisms permitting nonpolymorphic CD1 molecules to present lipid antigens that differ considerably in polar head and aliphatic tails remain elusive. It is also unclear why hydrophobic motifs in the aliphatic tails of some antigens, which presumably embed inside CD1 pockets, contribute to determinants for T-cell recognition. The 1.9-Å crystal structure of an active complex of CD1b and a mycobacterial diacylsulfoglycolipid presented here provides some clues. Upon antigen binding, endogenous spacers of CD1b, which consist of a mixture of diradylglycerols, moved considerably within the lipid-binding groove. Spacer displacement was accompanied by F’ pocket closure and an extensive rearrangement of residues exposed to T-cell receptors. Such structural reorganization resulted in reduction of the A’ pocket capacity and led to incomplete embedding of the methyl-ramified portion of the phthioceranoyl chain of the antigen, explaining why such hydrophobic motifs are critical for T-cell receptor recognition. Mutagenesis experiments supported the functional importance of the observed structural alterations for T-cell stimulation. Overall, our data delineate a complex molecular mechanism combining spacer repositioning and ligand-induced conformational changes that, together with pocket intricacy, endows CD1b with the required molecular plasticity to present a broad range of structurally diverse antigens. PMID:22006319

  12. Human alveolar macrophages present antigen ineffectively due to defective expression of B7 costimulatory cell surface molecules.

    PubMed Central

    Chelen, C J; Fang, Y; Freeman, G J; Secrist, H; Marshall, J D; Hwang, P T; Frankel, L R; DeKruyff, R H; Umetsu, D T

    1995-01-01

    Alveolar macrophages, resident phagocytic cells in the lung that derive from peripheral blood monocytes, are paradoxically ineffective in presenting antigen to T cells. We found that antigen presentation by alveolar macrophages could be restored by the addition of anti-CD28 mAb to cultures of T cells and macrophages, indicating that costimulation by alveolar macrophages via the CD28 pathway was defective. In addition, we found that alveolar macrophages activated with IFN-gamma failed to express B7-1 or B7-2 antigens, which normally ligate CD28 on T cells and provide a costimulatory signal required for the activation of T cells. These observations are the first to demonstrate the inability of a "professional" antigen-presenting cell type to effectively express the costimulatory molecules B7-1 and B7-2. Inasmuch as immune reactions within the lung are inevitably associated with inflammatory injury to pulmonary tissue, these observations suggest that reduced expression of B7-1 and B7-2 by alveolar macrophages may be advantageous, as a critical mechanism involved in the induction of peripheral tolerance to the abundance of antigens to which mucosal tissues are continuously exposed. PMID:7533793

  13. Antigen presentation and cytotoxic T lymphocyte killing studied in individual, living cells.

    PubMed

    Hahn, K; DeBiasio, R; Tishon, A; Lewicki, H; Gairin, J E; LaRocca, G; Taylor, D L; Oldstone, M

    1994-06-01

    Interactions between individual, living fibroblasts and cytotoxic T lymphocyte (CTL) clones were analyzed by using video-enhanced differential interference contrast and fluorescence microscopy in a multimode configuration. Fibroblasts expressing known major histocompatibility complex I alleles (MC57: H-2b; Balb: H-2d) were sensitized for killing by incubating or microinjecting them with peptide fragments of lymphocytic choriomeningitis virus. Previous determination of the CTL clones' specificity for these peptides and MHC-I alleles enabled us to study CTL killing of fibroblasts, and nonlethal CTL interaction with targets due to "mismatches" of the CTL, target, and/or peptide. During viral peptide-specific MHC-restricted CTL killing, distinct morphological alterations were observed (CTL shape changes, movements of granules in CTL cytoplasm, and target cell contraction and blebbing). When no killing occurred, CTL engaged in prolonged, nonrandom movement on the target cells. Alloreactive and virus-specific CTL displayed the same morphology during killing. To study antigen presentation further within individual, living cells, a LCMV glycoprotein peptide (aa 272-286, LSDSSGVENPGGYCL) was covalently labeled with tetramethylrhodamine. In 51Cr release assays, the labeled peptide specifically induced potent CTL killing, but neither labeled nor unlabeled peptide proved toxic for unsensitized targets. Microinjection of the labeled peptide into the cytoplasm of fibroblast cells led to CTL killing of those cells, yet nearby uninjected cells contacted by CTL were not killed, indicating that killing was due to presentation of microinjected peptide rather than binding of extracellular peptide to cell surface MHC. Peptide-injected target cells were killed only when combined with CTL specific for the peptide and for the MHC allele of the injected cell.

  14. A Toll-like receptor 2 agonist-fused antigen enhanced antitumor immunity by increasing antigen presentation and the CD8 memory T cells population

    PubMed Central

    Wu, Chiao-Chieh; Liu, Shih-Jen; Chen, Hsin-Wei; Shen, Kuan-Yin; Leng, Chih-Hsiang

    2016-01-01

    The induction of long-lived effector CD8+ T cells is key to the development of efficient cancer vaccines. In this study, we demonstrated that a Toll-like receptor 2 (TLR2) agonist-fused antigen increased antigen presentation via TLR2 signaling and induced effector memory-like CD8+ T cells against cancer after immunization. The N-terminus of ovalbumin (OVA) was biologically fused with a bacterial lipid moiety TLR2 agonist to produce a recombinant lipidated ovalbumin (rlipo-OVA). We demonstrated that rlipo-OVA activated bone marrow-derived dendritic cells (BM-DCs) maturation and increased antigen presentation by major histocompatibility complex (MHC) class I via TLR2. After immunization, rlipo-OVA skewed the immune response towards T helper (Th) 1 and induced OVA-specific cytotoxic T lymphocyte (CTL) responses. Moreover, immunization with rlipo-OVA induced higher numbers of effector memory (CD44+CD62L−) CD8+ T cells compared with recombinant ovalbumin (rOVA) alone or rOVA mixed with the TLR2 agonist Pam3CSK4. Accordingly, the CD27+CD43+ effector memory CD8+ T cells expressed high levels of the long-lived CD127 marker. The administration of rlipo-OVA could inhibit tumor growth, but the anti-tumor effects were lost after the depletion of CD8 or CD127 cells in vivo. These findings suggested that the TLR2 agonist-fused antigen induced long-lived memory CD8+ T cells for efficient cancer therapy. PMID:27127171

  15. Differential uptake and cross-presentation of soluble and necrotic cell antigen by human DC subsets.

    PubMed

    Chiang, Meng-Chieh; Tullett, Kirsteen M; Lee, Yoke Seng; Idris, Adi; Ding, Yitian; McDonald, Kylie J; Kassianos, Andrew; Leal Rojas, Ingrid M; Jeet, Varinder; Lahoud, Mireille H; Radford, Kristen J

    2016-02-01

    Cross-presentation is the mechanism by which exogenous Ag is processed for recognition by CD8(+) T cells. Murine CD8α(+) DCs are specialized at cross-presenting soluble and cellular Ag, but in humans this process is poorly characterized. In this study, we examined uptake and cross-presentation of soluble and cellular Ag by human blood CD141(+) DCs, the human equivalent of mouse CD8α(+) DCs, and compared them with human monocyte-derived DCs (MoDCs) and blood CD1c(+) DC subsets. MoDCs were superior in their capacity to internalize and cross-present soluble protein whereas CD141(+) DCs were more efficient at ingesting and cross-presenting cellular Ag. Whilst cross-presentation by CD1c(+) DCs and CD141(+) DCs was dependent on the proteasome, and hence cytosolic translocation, cross-presentation by MoDCs was not. Inhibition of endosomal acidification enhanced cross-presentation by CD1c(+) DCs and MoDCs but not by CD141(+) DCs. These data demonstrate that CD1c(+) DCs, CD141(+) DCs, and MoDCs are capable of cross-presentation; however, they do so via different mechanisms. Moreover, they demonstrate that human CD141(+) DCs, like their murine CD8α(+) DC counterparts, are specialized at cross-presenting cellular Ag, most likely mediated by an enhanced capacity to ingest cellular Ag combined with subtle changes in lysosomal pH during Ag processing and use of the cytosolic pathway.

  16. Cell surface phenotype and ultramicroscopic analysis of purified human enterocytes: a possible antigen-presenting cell in the intestine.

    PubMed

    Martín-Villa, J M; Ferre-López, S; López-Suárez, J C; Corell, A; Pérez-Blas, M; Arnaiz-Villena, A

    1997-12-01

    Epithelial cells of the intestine seem to act as antigen-presenting cells to surrounding lymphoid tissue and may be crucial to maintain the pool of peripheral T lymphocytes. The scope of this study was to carry out an immunophenotypic and ultramicroscopic analysis of purified human enterocytes to elucidate their role as antigen-presenting cells, in the immune responses in the gut-associated lymphoid tissue. A method has been developed to obtain purified and viable human enterocyte populations, later labeled with relevant monoclonal antibodies directed to leukocyte antigens and subjected to cytofluorometric analysis. Phenotypic analysis revealed the presence of markers common to "classical" antigen-presenting cells (CD14, CD35, CD39, CD43, CD63 and CD64), reinforcing the idea that enterocytes may act as such. Moreover, several integrins (CD11b, CD11c, CD18, CD41a, CD61 and CD29) were also found. CD25 (IL-2 receptor alpha chain) and CD28, characteristic of T cells, were detected on the surface of these cells; this latter finding rises the possibility that enterocytes could be activated by IL-2 and/or via CD28 through binding to its ligands CD80 or CD86. Finally, the presence of CD21, CD32, CD35 and CD64 that may bind immune complexes via Fc or C3, suggests their participation in the metabolism of immune complexes. Furthermore, the finding of a Birbeck's-like granule in the cytoplasm of the cells, shows that enterocytes contain an ultramicroscopic feature previously thought to be characteristic of Langerhans' cells, an antigen-presenting cell. The phenotype detected on the surface of enterocytes, along with their ultramicroscopic characteristics, suggests that they may play an important role in the immune responses elicited in the gut, presenting antigens to surrounding lymphoid cells, and establishing cognate interactions with them.

  17. Past, Present, and Future Capabilities of the Transonic Dynamics Tunnel from an Aeroelasticity Perspective

    NASA Technical Reports Server (NTRS)

    Cole, Stanley R.; Garcia, Jerry L.

    2000-01-01

    The NASA Langley Transonic Dynamics Tunnel (TDT) has provided a unique capability for aeroelastic testing for forty years. The facility has a rich history of significant contributions to the design of many United States commercial transports, military aircraft, launch vehicles, and spacecraft. The facility has many features that contribute to its uniqueness for aeroelasticity testing, perhaps the most important feature being the use of a heavy gas test medium to achieve higher test densities. Higher test medium densities substantially improve model-building requirements and therefore simplify the fabrication process for building aeroelastically scaled wind tunnel models. Aeroelastic scaling for the heavy gas results in lower model structural frequencies. Lower model frequencies tend to a make aeroelastic testing safer. This paper will describe major developments in the testing capabilities at the TDT throughout its history, the current status of the facility, and planned additions and improvements to its capabilities in the near future.

  18. “Danger” Conditions Increase Sulfamethoxazole-Protein Adduct Formation in Human Antigen-Presenting Cells

    PubMed Central

    Lavergne, S. N.; Wang, H.; Callan, H. E.; Park, B. K.

    2009-01-01

    Antigen-presenting cells (APC) are thought to play an important role in the pathogenesis of drug-induced immune reactions. Various pathological factors can activate APC and therefore influence the immune equilibrium. It is interesting that several diseases have been associated with an increased rate of drug allergy. The aim of this project was to evaluate the impact of such “danger signals” on sulfamethoxazole (SMX) metabolism in human APC (peripheral blood mononuclear cells, Epstein-Barr virus-modified B lymphocytes, monocyte-derived dendritic cells, and two cell lines). APC were incubated with SMX (100 μM–2 mM; 5 min–24 h), in the presence of pathological factors: bacterial endotoxins (lipopolysaccharide and staphylococcal enterotoxin B), flu viral proteins, cytokines [interleukin (IL)-1β, IL-6, IL-10; tumor necrosis factor-α; interferon-γ; and transforming growth factor-β], inflammatory molecules (prostaglandin E2, human serum complement, and activated protein C), oxidants (buthionine sulfoximine and H2O2), and hyperthermia (37.5–39.5°C). Adduct formation was evaluated by enzyme-linked immunosorbent assay and confocal microscopy. SMX-protein adduct formation was time- and concentration-dependent for each cell type tested, in both physiological and danger conditions. A danger environment significantly increased the formation of SMX-protein adducts and significantly shortened the delay for their detection. An additive effect was observed with a combination of danger signals. Dimedone (chemical selectively binding cysteine sulfenic acid) and antioxidants decreased both baseline and danger-enhanced SMX-adduct formation. Various enzyme inhibitors were associated with a significant decrease in SMX-adduct levels, with a pattern varying depending on the cell type and the culture conditions. These results illustrate that danger signals enhance the formation of intracellular SMX-protein adducts in human APC. These findings might be relevant to the

  19. "Danger" conditions increase sulfamethoxazole-protein adduct formation in human antigen-presenting cells.

    PubMed

    Lavergne, S N; Wang, H; Callan, H E; Park, B K; Naisbitt, D J

    2009-11-01

    Antigen-presenting cells (APC) are thought to play an important role in the pathogenesis of drug-induced immune reactions. Various pathological factors can activate APC and therefore influence the immune equilibrium. It is interesting that several diseases have been associated with an increased rate of drug allergy. The aim of this project was to evaluate the impact of such "danger signals" on sulfamethoxazole (SMX) metabolism in human APC (peripheral blood mononuclear cells, Epstein-Barr virus-modified B lymphocytes, monocyte-derived dendritic cells, and two cell lines). APC were incubated with SMX (100 microM-2 mM; 5 min-24 h), in the presence of pathological factors: bacterial endotoxins (lipopolysaccharide and staphylococcal enterotoxin B), flu viral proteins, cytokines [interleukin (IL)-1beta, IL-6, IL-10; tumor necrosis factor-alpha; interferon-gamma; and transforming growth factor-beta], inflammatory molecules (prostaglandin E2, human serum complement, and activated protein C), oxidants (buthionine sulfoximine and H(2)O(2)), and hyperthermia (37.5-39.5 degrees C). Adduct formation was evaluated by enzyme-linked immunosorbent assay and confocal microscopy. SMX-protein adduct formation was time- and concentration-dependent for each cell type tested, in both physiological and danger conditions. A danger environment significantly increased the formation of SMX-protein adducts and significantly shortened the delay for their detection. An additive effect was observed with a combination of danger signals. Dimedone (chemical selectively binding cysteine sulfenic acid) and antioxidants decreased both baseline and danger-enhanced SMX-adduct formation. Various enzyme inhibitors were associated with a significant decrease in SMX-adduct levels, with a pattern varying depending on the cell type and the culture conditions. These results illustrate that danger signals enhance the formation of intracellular SMX-protein adducts in human APC. These findings might be relevant

  20. Association of Polymorphisms in HLA Antigen Presentation-Related Genes with the Outcomes of HCV Infection

    PubMed Central

    Lu, Xiaomei; Xu, Yin; Wang, Jie; Zhang, Yun; Yu, Rongbin; Su, Jing

    2015-01-01

    Antigen-presentation genes play a vital role in the pathogenesis of HCV infection. However, the relationship of variants of these genes with spontaneous outcomes of HCV infection has not been fully investigated. To explore novel loci in the Chinese population, 34 tagging-SNPs in 9 candidate genes were genotyped for their associations with the outcomes of HCV infection. The distributions of different genotypes and haplotypes were compared among 773 HCV-negative controls, 246 subjects with HCV natural clearance, and 218 HCV persistent carriers recruited from hemodialysis patients and intravenous drug users. Our study implicated that TAP2, HLA-DOA, HLA-DOB, and tapasin loci were novel candidate regions for susceptibility to HCV infection and viral clearance in the Chinese population. Logistic regression analyses showed that TAP2 rs1800454 A (OR = 1.48, P = 0.002) and HLA-DOB rs2071469 G (OR = 1.23, P = 0.048) were significantly associated with increased susceptibility to establishment of HCV infection. However, high-risk behavior exposure and age were stronger predictors of HCV infection. Mutation of tapasin rs9277972 T (OR = 1.57, P =0.043) increased the risk of HCV chronicity, and HLA-DOA rs3128935 C (OR = 0.62, P = 0.019) increased the chance of viral resolution. With regards to the effect of rs3128925, interactions were found with high-risk behavior (P = 0.013) and age (P = 0.035). The risk effect of rs3128925 T for persistent HCV infection was higher in injecting drug users (vs. dialysis patients) and in subjects ≥ 40 years old (vs. < 40 years old). PMID:25874709

  1. Prior stimulation of antigen-presenting cells with Lactobacillus regulates excessive antigen-specific cytokine responses in vitro when compared with Bacteroides

    PubMed Central

    Tsuda, Masato; Yanagibashi, Tsutomu; Hachimura, Satoshi; Hirayama, Kazuhiro; Itoh, Kikuji; Takahashi, Kyoko; Kaminogawa, Shuichi

    2007-01-01

    The development of allergy is related to differences in the intestinal microbiota. Therefore, it is suggested that the immune responses induced by different genera of bacteria might be regulated through adaptive as well as innate immunity. In this study, we examined whether antigen-specific immune responses were affected by stimulation with the different genera of intestinal bacteria in vitro. Mesenteric lymph node (MLN) cells isolated from germ-free ovalbumin (OVA)-specific T cell receptor transgenic (OVA-Tg) mice were stimulated with OVA and intestinal bacteria. Cecal contents from conventional mice but not germ-free mice could induce OVA-specific cytokine production. Among the murine intestinal bacteria, Bacteroides acidofaciens (BA) enhanced OVA-specific IFN-γ and IL-10 production while Lactobacillusjohnsonii (LA) increased OVA-specific IL-10 production only. The expression of cell surface molecules and cytokine production by antigen-presenting cells (APCs) from germ-free Balb/c mice were analyzed. BA increased the expression of MHC II and co-stimulatory molecules on APCs compared with LA. BA increased IL-6 and IL-10 production but induced less IL-12p40 than LA. To examine the effects of prior stimulation of APCs by intestinal bacteria on the induction of antigen-specific immune responses, cytokine production was determined following co-culture with OVA, CD4+ T cells from OVA-Tg mice, and APCs which were pre-stimulated with the bacteria or not. APCs pre-stimulated with LA did not enhance OVA-specific cytokine production while BA stimulated OVA-specific IL-10 production. These results suggest that the prior stimulation of intestinal immunocytes by Lactobacillus might regulate excessive antigen-specific cytokine responses via APCs when compared with prior stimulation by Bacteroides. PMID:19002998

  2. Perceptions of Present and Future Capability among a Sample of Rural British Columbia Youth Perceptions

    ERIC Educational Resources Information Center

    Kapil, Meg E.; Shepard, Blythe C.

    2011-01-01

    A cross-sectional survey explored 96 rural adolescents' perceptions of their rural context and how their self-concept is related to perceptions of capability regarding hopes and fears for the future. The youth surveyed, from the Kootenay Boundary region of British Columbia, indicated ambivalence about staying in their communities after leaving…

  3. The proteasome activator 11 S REG (PA28) and class I antigen presentation.

    PubMed Central

    Rechsteiner, M; Realini, C; Ustrell, V

    2000-01-01

    There are two immune responses in vertebrates: humoral immunity is mediated by circulating antibodies, whereas cytotoxic T lymphocytes (CTL) confer cellular immunity. CTL lyse infected cells upon recognition of cell-surface MHC Class I molecules complexed with foreign peptides. The displayed peptides are produced in the cytosol by degradation of host proteins or proteins from intracellular pathogens that might be present. Proteasomes are cylindrical multisubunit proteases that generate many of the peptides eventually transferred to the cell surface for immune surveillance. In mammalian proteasomes, six active sites face a central chamber. As this chamber is sealed off from the enzyme's surface, there must be mechanisms to promote entry of substrates. Two protein complexes have been found to bind the ends of the proteasome and activate it. One of the activators is the 19 S regulatory complex of the 26 S proteasome; the other activator is '11 S REG' [Dubiel, Pratt, Ferrell and Rechsteiner (1992) J. Biol. Chem. 267, 22369-22377] or 'PA28' [Ma, Slaughter and DeMartino (1992) J. Biol. Chem. 267, 10515-10523]. During the past 7 years, our understanding of the structure of REG molecules has increased significantly, but much less is known about their biological functions. There are three REG subunits, namely alpha, beta and gamma. Recombinant REGalpha forms a ring-shaped heptamer of known crystal structure. 11 S REG is a heteroheptamer of alpha and beta subunits. REGgamma is also presumably a heptameric ring, and it is found in the nuclei of the nematode work Caenorhabditis elegans and higher organisms, where it may couple proteasomes to other nuclear components. REGalpha and REGbeta, which are abundant in vertebrate immune tissues, are located mostly in the cytoplasm. Synthesis of REG alpha and beta subunits is induced by interferon-gamma, and this has led to the prevalent hypothesis that REG alpha/beta hetero-oligomers play an important role in Class I antigen

  4. Ex vivo programming of antigen-presenting B lymphocytes: considerations on DNA uptake and cell activation.

    PubMed

    Wheeler, Matthew; Cortez-Gonzalez, Xotchil; Frazzi, Raffaele; Zanetti, Maurizio

    2006-01-01

    Plasmids used in DNA vaccination not only serve as a source of antigen, but also have an important adjuvant effect. This review focuses on recent advancements made in understanding how cells internalize DNA, and how internalized DNA activates immune response pathways. We also comment on the role of B cells in both of these processes.

  5. Antigen presentation by small intestinal epithelial cells uniquely enhances IFN-γ secretion from CD4{sup +} intestinal intraepithelial lymphocytes

    SciTech Connect

    Hatano, Ryo; Yamada, Kiyoshi; Iwamoto, Taku; Maeda, Nana; Emoto, Tetsuro; Shimizu, Makoto; Totsuka, Mamoru

    2013-06-14

    Highlights: •Small intestinal epithelial cells (sIECs). •sIECs are able to induce antigen specific proliferation of CD4{sup +} IELs. •sIECs induce markedly enhanced IFN-γ secretion by CD4{sup +} IELs. •Induction of enhanced IFN-γ secretion by sIECs is uniquely observed in CD4{sup +} IELs. -- Abstract: Small intestinal epithelial cells (sIECs) express major histocompatibility complex class II molecules even in a normal condition, and are known to function as antigen presenting cells (APCs) at least in vitro. These findings raised the possibility that sIECs play an important role in inducing immune responses against luminal antigens, especially those of intestinal intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs). We herein showed that antigenic stimulation with sIECs induced markedly greater secretion of interferon-gamma (IFN-γ) by CD4{sup +} IELs, but not interleukin (IL)-4, IL-10 and IL-17 although the proliferative response was prominently lower than that with T cell-depleted splenic APCs. In contrast, no enhanced IFN-γ secretion by CD4{sup +} LPLs and primed splenic CD4{sup +} T cells was observed when stimulated with sIECs. Taken together, these results suggest that sIECs uniquely activate CD4{sup +} IELs and induce remarkable IFN-γ secretion upon antigenic stimulation in vivo.

  6. Lead enhances CD4{sup +} T cell proliferation indirectly by targeting antigen presenting cells and modulating antigen-specific interactions

    SciTech Connect

    Farrer, David G.; Hueber, Sara M.; McCabe, Michael J. . E-mail: michael_mccabe@urmc.rochester.edu

    2005-09-01

    Although Pb is a well-known immunotoxicant, its mechanism of action is not well understood. Low levels of Pb ({approx}1 {mu}M) markedly enhance the proliferative T cell response in mixed lymphocyte culture (MLC), a process we have termed allo-enhancement. As Pb allo-enhancement occurs whether alloantigen presenting cells (APC) are derived from C57BL/6 or BALB.B10, the allo-reactive T cells involved are likely to be specific for peptide in the context of the IA{sup b} molecule as the IE molecule is null in H-2{sup b} mice. Analysis of T cell division in MLC with Pb treatment indicated that there was no significant difference between Pb and non-Pb-treated cultures until day 4 when the frequency of proliferating T cells was much greater than in non-treated cultures. Our data suggest that this increased proliferation is not coupled with increased IL-2 levels in the media as these were actually decreased with Pb treatment and that Pb-induced enhancement in the allo-proliferative response is only partially dependent upon IL-2. Pb allo-enhancement is abrogated when stimulating allo-APCs are paraformaldehyde-fixed, and T cell proliferation stimulated by concanavalin A is not enhanced with Pb treatment, suggesting that the APC is the proximate target of Pb in allo-MLC. Pb allo-enhancement does not occur when T cells respond to irradiated allo-B cells, alone; however, it is restored when syngeneic CD11c-enriched cells are added. Of the CD11c-enriched splenocytes, the fraction that is adherent after 24 h, consistent with macrophages, appears to be the cell type targeted by Pb. Using T cells from DO11.10 transgenic mice, we determined that the effect of Pb is centered around specific p:MHC interactions and that enhanced costimulation is an unlikely mechanism for Pb allo-enhancement.

  7. Rheumatoid arthritis vaccine therapies: perspectives and lessons from therapeutic ligand epitope antigen presentation system vaccines for models of rheumatoid arthritis.

    PubMed

    Rosenthal, Kenneth S; Mikecz, Katalin; Steiner, Harold L; Glant, Tibor T; Finnegan, Alison; Carambula, Roy E; Zimmerman, Daniel H

    2015-06-01

    The current status of therapeutic vaccines for autoimmune diseases is reviewed with rheumatoid arthritis as the focus. Therapeutic vaccines for autoimmune diseases must regulate or subdue responses to common self-antigens. Ideally, such a vaccine would initiate an antigen-specific modulation of the T-cell immune response that drives the inflammatory disease. Appropriate animal models and types of T helper cells and signature cytokine responses that drive autoimmune disease are also discussed. Interpretation of these animal models must be done cautiously because the means of initiation, autoantigens, and even the signature cytokine and T helper cell (Th1 or Th17) responses that are involved in the disease may differ significantly from those in humans. We describe ligand epitope antigen presentation system vaccine modulation of T-cell autoimmune responses as a strategy for the design of therapeutic vaccines for rheumatoid arthritis, which may also be effective in other autoimmune conditions.

  8. Rheumatoid arthritis vaccine therapies: perspectives and lessons from therapeutic ligand epitope antigen presentation system vaccines for models of rheumatoid arthritis

    PubMed Central

    Rosenthal, Kenneth S.; Mikecz, Katalin; Steiner, Harold L.; Glant, Tibor T.; Finnegan, Alison; Carambula, Roy E.; Zimmerman, Daniel H.

    2016-01-01

    The current status of therapeutic vaccines for autoimmune diseases is reviewed with rheumatoid arthritis as the focus. Therapeutic vaccines for autoimmune diseases must regulate or subdue responses to common self-antigens. Ideally, such a vaccine would initiate an antigen-specific modulation of the T-cell immune response that drives the inflammatory disease. Appropriate animal models and types of T helper cells and signature cytokine responses that drive autoimmune disease are also discussed. Interpretation of these animal models must be done cautiously because the means of initiation, autoantigens, and even the signature cytokine and T helper cell (Th1 or Th17) responses that are involved in the disease may differ significantly from those in humans. We describe ligand epitope antigen presentation system vaccine modulation of T-cell autoimmune responses as a strategy for the design of therapeutic vaccines for rheumatoid arthritis, which may also be effective in other autoimmune conditions. PMID:25787143

  9. Octaarginine-modified liposomes enhance cross-presentation by promoting the C-terminal trimming of antigen peptide.

    PubMed

    Nakamura, Takashi; Ono, Kouhei; Suzuki, Yoshiteru; Moriguchi, Rumiko; Kogure, Kentaro; Harashima, Hideyoshi

    2014-08-04

    Exogenous antigen proteolysis by proteasomes and amino peptidases is essential for the production of mature major histocompatibility complex class I (MHC-I) peptides to induce cross-presentation. We report here that when liposomes are modified with octaarginine (R8-Lip), a type of cell-penetrating peptide, the production of the mature MHC-I peptide is enhanced by promoting the C-terminal trimming of the antigen peptide. The efficiency of cross-presentation of ovalbumin (OVA) using the R8-Lip was dramatically higher than that by octalysine modified liposomes (K8-Lip) in mouse bone-marrow derived dendritic cells (BMDCs), although the physical characters of both liposomes were comparable. In this study, we investigated the mechanism responsible for the enhancement in cross-presentation by R8-Lip. Although the efficiencies of cellular uptake, endosomal escape, proteolysis of OVA and DC maturation between the two systems were essentially the same, an analysis of peptide trimming to SIINFEKL (mature MHC-I peptide of OVA) by using R8-Lip and K8-Lip encapsulating peptides of various length clearly indicates that the use of R8-Lip enhances the efficiency of the C-terminal cleavage of antigen-derived peptides. This finding provides a new strategy for achieving efficient cross-presentation by using R8 peptide and arginine-rich peptides. Moreover, this result may contribute to the development of a new paradigm regarding the machinery associated with antigen peptide production.

  10. Regulation of the polarization of T cells toward antigen-presenting cells by Ras-related GTPase CDC42.

    PubMed Central

    Stowers, L; Yelon, D; Berg, L J; Chant, J

    1995-01-01

    The mechanisms by which cells rapidly polarize in the direction of external signals are not understood. Helper T cells, when contacted by an antigen-presenting cell, polarize their cytoskeletons toward the antigen-presenting cell within minutes. Here we show that, in T cells, the mammalian Ras-related GTPase CDC42 (the homologue of yeast CDC42, a protein involved in budding polarity) can regulate the polarization of both actin and microtubules toward antigen-presenting cells but is not involved in other T-cell signaling processes such as those which culminate in interleukin 2 production. Although T-cell polarization appears dispensable for signaling leading to interleukin 2 production, polarization may direct lymphokine secretion towards the correct antigen-presenting cell in a crowded cellular environment. Inhibitor experiments suggest that phosphatidylinositol 3-kinase is required for cytoskeletal polarization but that calcineurin activity, known to be important for other aspects of signaling, is not. Apparent conservation of CDC42 function between yeast and T cells suggests that this GTPase is a general regulator of cytoskeletal polarity in many cell types. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:7761442

  11. IgE/FcεRI-Mediated Antigen Cross-Presentation by Dendritic Cells Enhances Anti-Tumor Immune Responses.

    PubMed

    Platzer, Barbara; Elpek, Kutlu G; Cremasco, Viviana; Baker, Kristi; Stout, Madeleine M; Schultz, Cornelia; Dehlink, Eleonora; Shade, Kai-Ting C; Anthony, Robert M; Blumberg, Richard S; Turley, Shannon J; Fiebiger, Edda

    2015-03-03

    Epidemiologic studies discovered an inverse association between immunoglobulin E (IgE)-mediated allergies and cancer, implying tumor-protective properties of IgE. However, the underlying immunologic mechanisms remain poorly understood. Antigen cross-presentation by dendritic cells (DCs) is of key importance for anti-tumor immunity because it induces the generation of cytotoxic CD8(+) T lymphocytes (CTLs) with specificity for tumor antigens. We demonstrate that DCs use IgE and FcεRI, the high-affinity IgE receptor, for cross-presentation and priming of CTLs in response to free soluble antigen at low doses. Importantly, IgE/FcεRI-mediated cross-presentation is a distinct receptor-mediated pathway because it does not require MyD88 signals or IL-12 induction in DCs. Using passive immunization with tumor antigen-specific IgE and DC-based vaccination experiments, we demonstrate that IgE-mediated cross-presentation significantly improves anti-tumor immunity and induces memory responses in vivo. Our findings suggest a cellular mechanism for the tumor-protective features of IgE and expand the known physiological functions of this immunoglobulin. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  12. The effect of CpG-ODN on antigen presenting cells of the foal

    PubMed Central

    Flaminio, M Julia BF; Borges, Alexandre S; Nydam, Daryl V; Horohov, David W; Hecker, Rolf; Matychak, Mary Beth

    2007-01-01

    Background Cytosine-phosphate-guanosine oligodeoxynucleotide (CpG-ODN) has been used successfully to induce immune responses against viral and intracellular organisms in mammals. The main objective of this study was to test the effect of CpG-ODN on antigen presenting cells of young foals. Methods Peripheral blood monocytes of foals (n = 7) were isolated in the first day of life and monthly thereafter up to 3 months of life. Adult horse (n = 7) monocytes were isolated and tested once for comparison. Isolated monocytes were stimulated with IL-4 and GM-CSF (to obtain dendritic cells, DC) or not stimulated (to obtain macrophages). Macrophages and DCs were stimulated for 14–16 hours with either CpG-ODN, LPS or not stimulated. The stimulated and non-stimulated cells were tested for cell surface markers (CD86 and MHC class II) using flow cytometry, mRNA expression of cytokines (IL-12, IFNα, IL-10) and TLR-9 using real time quantitative RT-PCR, and for the activation of the transcription factor NF-κB p65 using a chemiluminescence assay. Results The median fluorescence of the MHC class II molecule in non-stimulated foal macrophages and DCs at birth were 12.5 times and 11.2 times inferior, respectively, than adult horse cells (p = 0.009). That difference subsided at 3 months of life (p = 0.3). The expression of the CD86 co-stimulatory molecule was comparable in adult horse and foal macrophages and DCs, independent of treatment. CpG-ODN stimulation induced IL-12p40 (53 times) and IFNα (23 times) mRNA expression in CpG-ODN-treated adult horse DCs (p = 0.078), but not macrophages, in comparison to non-stimulated cells. In contrast, foal APCs did not respond to CpG-ODN stimulation with increased cytokine mRNA expression up to 3 months of age. TLR-9 mRNA expression and NF-kB activation (NF-kB p65) in foal DCs and macrophages were comparable (p > 0.05) to adult horse cells. Conclusion CpG-ODN treatment did not induce specific maturation and cytokine expression in foal

  13. A Ubiquitin Independent Degradation Pathway Utilized by a Hepatitis B Virus Envelope Protein to Limit Antigen Presentation

    PubMed Central

    Liu, Yuanjie; Testa, James S.; Philip, Ramila; Block, Timothy M.; Mehta, Anand S.

    2011-01-01

    Hepatitis B virus envelope glycoproteins Large (L), Middle (M) and Small (S) are targets of the host cellular immune system. The extent to which the host recognizes viral antigens presented by infected cells is believed to play a decisive role in determining if an infection will be resolved or become chronic. As with other antigens, HBV envelope polypeptides must be degraded, presumably by cellular proteasomes, to be presented by the MHC I pathway. We have used M as a model to study this process and determine how ER quality control monitors these foreign polymeric proteins and disposes of them through the ER-associated degradation (ERAD) pathway. Using both wild type and mutant HBV M protein, we found that unlike most ERAD substrates, which require ubiquitination for retrotranslocation and degradation, the HBV M protein, which only contains two lysine residues, can undergo rapid and complete, ubiquitin independent, proteasome dependent degradation. The utilization of this pathway had a functional consequence, since proteins degraded through it, were poorly presented via MHC I. To test the hypothesis that the level of ubiquitination, independent of protein degradation, controls the level of antigen presentation, we inserted two additional lysines into both the wild type and mutant M protein. Amazingly, while the addition of the lysine residues dramatically increased the level of ubiquitination, it did not alter the rate of degradation. However and remarkably, the increased ubiquitination was associated with a dramatic increase in the level of antigen presentation. In conclusion, using the HBV surface protein as a model, we have identified a novel ubiquitin independent degradation pathway and determined that this pathway can have implications for antigen presentation and potentially viral pathogenesis. PMID:21969857

  14. Granuloma cells in chronic inflammation express CD205 (DEC205) antigen and harbor proliferating T lymphocytes: similarity to antigen-presenting cells.

    PubMed

    Ohtani, Haruo

    2013-02-01

    Granulomas are classified as immune or foreign body granulomas. Of these, the immune granulomas, a hallmark of granulomatous inflammation, are closely related to cell-mediated immune responses. The aim of the present study is to characterize immune granuloma cells in 33 patients with granulomatous inflammation focusing on the expression of CD205 (DEC205), a cell surface marker of antigen presenting cells, and their spatial relationship to T cells. CD205 was frequently expressed by immune granuloma cells, in contrast to foreign body granuloma cells that lacked CD205 expression. T cells were not only distributed in a lymphocyte collar around the granuloma, but also present among the granuloma cells (termed 'intra-granuloma T cells'). Intra-granuloma T cells stained positive for Ki-67 (median positivity = 9.4%) by double immunostaining for CD3 and Ki-67. This indicated the presence of proliferative stimuli within the granuloma that could activate the intra-granuloma T cells. The labeling index of Ki-67 in intra-granuloma T cells was significantly higher than that of T cells in the lymphocyte collar (P < 0.0001) or T cells in the T cell zone (paracortex) of chronic tonsillitis or reactive lymphadenitis (P = 0.002). These data indicate a close similarity between immune granulomas and antigen presenting cells.

  15. Transduction of Human Antigen-Presenting Cells with Integrase-Defective Lentiviral Vector Enables Functional Expansion of Primed Antigen-Specific CD8+ T Cells

    PubMed Central

    Bona, Roberta; Michelini, Zuleika; Leone, Pasqualina; Macchia, Iole; Klotman, Mary E.; Salvatore, Mirella

    2010-01-01

    Abstract Nonintegrating lentiviral vectors are being developed as a efficient and safe delivery system for both gene therapy and vaccine purposes. Several reports have demonstrated that a single immunization with integration-defective lentiviral vectors (IDLVs) delivering viral or tumor model antigens in mice was able to elicit broad and long-lasting specific immune responses in the absence of vector integration. At present, no evidence has been reported showing that IDLVs are able to expand preexisting immune responses in the human context. In the present study, we demonstrate that infection of human antigen-presenting cells (APCs), such as monocyte-derived dendritic cells (DCs) and macrophages with IDLVs expressing influenza matrix M1 protein resulted in effective induction of in vitro expansion of M1-primed CD8+ T cells, as evaluated by both pentamer staining and cytokine production. This is the first demonstration that IDLVs represent an efficient delivery system for gene transfer and expression in human APCs, useful for immunotherapeutic applications. PMID:20210625

  16. Messenger RNA Sequence Rather than Protein Sequence Determines the Level of Self-synthesis and Antigen Presentation of the EBV-encoded Antigen, EBNA1

    PubMed Central

    Tellam, Judy T.; Lekieffre, Lea; Zhong, Jie; Lynn, David J.; Khanna, Rajiv

    2012-01-01

    Unique purine-rich mRNA sequences embedded in the coding sequences of a distinct group of gammaherpesvirus maintenance proteins underlie the ability of the latently infected cell to minimize immune recognition. The Epstein-Barr virus nuclear antigen, EBNA1, a well characterized lymphocryptovirus maintenance protein has been shown to inhibit in cis antigen presentation, due in part to a large internal repeat domain encoding glycine and alanine residues (GAr) encoded by a purine-rich mRNA sequence. Recent studies have suggested that it is the purine-rich mRNA sequence of this repeat region rather than the encoded GAr polypeptide that directly inhibits EBNA1 self-synthesis and contributes to immune evasion. To test this hypothesis, we generated a series of EBNA1 internal repeat frameshift constructs and assessed their effects on cis-translation and endogenous antigen presentation. Diverse peptide sequences resulting from alternative repeat reading frames did not alleviate the translational inhibition characteristic of EBNA1 self-synthesis or the ensuing reduced surface presentation of EBNA1-specific peptide-MHC class I complexes. Human cells expressing the EBNA1 frameshift variants were also poorly recognized by antigen-specific T-cells. Furthermore, a comparative analysis of the mRNA sequences of the corresponding repeat regions of different viral maintenance homologues highlights the high degree of identity between the nucleotide sequences despite very little homology in the encoded amino acid sequences. Based on these combined observations, we propose that the cis-translational inhibitory effect of the EBNA1 internal repeat sequence operates mechanistically at the nucleotide level, potentially through RNA secondary structural elements, and is unlikely to be mediated through the GAr polypeptide. The demonstration that the EBNA1 repeat mRNA sequence and not the encoded protein sequence underlies immune evasion in this class of virus suggests a novel approach to

  17. Messenger RNA sequence rather than protein sequence determines the level of self-synthesis and antigen presentation of the EBV-encoded antigen, EBNA1.

    PubMed

    Tellam, Judy T; Lekieffre, Lea; Zhong, Jie; Lynn, David J; Khanna, Rajiv

    2012-12-01

    Unique purine-rich mRNA sequences embedded in the coding sequences of a distinct group of gammaherpesvirus maintenance proteins underlie the ability of the latently infected cell to minimize immune recognition. The Epstein-Barr virus nuclear antigen, EBNA1, a well characterized lymphocryptovirus maintenance protein has been shown to inhibit in cis antigen presentation, due in part to a large internal repeat domain encoding glycine and alanine residues (GAr) encoded by a purine-rich mRNA sequence. Recent studies have suggested that it is the purine-rich mRNA sequence of this repeat region rather than the encoded GAr polypeptide that directly inhibits EBNA1 self-synthesis and contributes to immune evasion. To test this hypothesis, we generated a series of EBNA1 internal repeat frameshift constructs and assessed their effects on cis-translation and endogenous antigen presentation. Diverse peptide sequences resulting from alternative repeat reading frames did not alleviate the translational inhibition characteristic of EBNA1 self-synthesis or the ensuing reduced surface presentation of EBNA1-specific peptide-MHC class I complexes. Human cells expressing the EBNA1 frameshift variants were also poorly recognized by antigen-specific T-cells. Furthermore, a comparative analysis of the mRNA sequences of the corresponding repeat regions of different viral maintenance homologues highlights the high degree of identity between the nucleotide sequences despite very little homology in the encoded amino acid sequences. Based on these combined observations, we propose that the cis-translational inhibitory effect of the EBNA1 internal repeat sequence operates mechanistically at the nucleotide level, potentially through RNA secondary structural elements, and is unlikely to be mediated through the GAr polypeptide. The demonstration that the EBNA1 repeat mRNA sequence and not the encoded protein sequence underlies immune evasion in this class of virus suggests a novel approach to

  18. Innate autoreactive B cells as antigen-presenting cells in the induction of tolerance to conserved keratin polypeptide.

    PubMed

    Fu, Meng; Li, Wei; Tian, Rong; Gao, Jixin; Xing, Ying; Li, Chengxin; Wang, Gang; Li, Chunying; Gao, Tianwen; Han, Hua; Liu, Yufeng

    2013-01-01

    Innate B cells account for a substantial proportion of total B lymphocytes and express autoreactive B cell receptors directed against self-constituents. However, whether innate autoreactive B cells present auto-antigens to T cells, and if so, whether they trigger an autoimmune response, are unclear. In this study, we have characterized splenic keratin-reactive B cells from naïve mice and investigated their roles in keratin antigen presentation. We observed that splenic keratin-reactive B cells expressed germline encoded VH and VK genes based on Igs from anti-keratin hybridomas. Moreover, they frequently utilized gene segment of DFL16.2 and JK2 in the CDR3 regions of heavy and light chain, suggesting that these cells are probably selected on the basis of the specificity of their BCRs. In the presence of keratin antigen, splenic keratin-reactive B cells stimulated significant IL-2 productions from keratin-specific T hybridomas, which were augmented by increasing the concentration of keratin and the numbers of keratin-reactive B cells. By contrast, keratin-reactive B cells failed to stimulate the proliferations of freshly isolated keratin-specific T cells from lymph nodes. The phenotypic analysis of splenic keratin-reactive B cells indicated that low expressions of B7-1 and B7-2 might be the underlying mechanisms for this incomplete function of B cell presentation. Our experiments indicate that splenic keratin-reactive B cells are ineffective in activating freshly isolated T cells from lymph nodes, suggesting a role for innate autoreactive B cells as antigen-presenting cells in tolerance to self-antigens.

  19. Hepatitis B virus-like particles access major histocompatibility class I and II antigen presentation pathways in primary dendritic cells.

    PubMed

    Moffat, Jessica M; Cheong, Wan-Shoo; Villadangos, José A; Mintern, Justine D; Netter, Hans J

    2013-04-26

    Virus-like particles (VLPs) represent high density displays of viral proteins that efficiently trigger immunity. VLPs composed of the small hepatitis B virus envelope protein (HBsAgS) are useful vaccine platforms that induce humoral and cellular immune responses. Notably, however, some studies suggest HBsAgS VLPs impair dendritic cell (DC) function. Here we investigated HBsAgS VLP interaction with DC subsets and antigen access to major histocompatibility complex (MHC) class I and II antigen presentation pathways in primary DCs. HBsAgS VLPs impaired plasmacytoid DC (pDC) interferon alpha (IFNα) production in response to CpG in vitro, but did not alter conventional DC (cDC) or pDC phenotype when administered in vivo. To assess cellular immune responses, HBsAgS VLPs were generated containing the ovalbumin (OVA) model epitopes OVA(257-264) and OVA(323-339) to access MHCI and MHCII antigen presentation pathways, respectively; both in vitro and following immunisation in vivo. HBsAgS VLP-OVA(257-264) elicited CTL responses in vivo that were not enhanced by inclusion of an additional MHCII helper epitope. HBsAgS VLP-OVA(257-264) administered in vivo was cross-presented by CD8(+) DCs, but not CD8(-) DCs. Therefore, HBsAgS VLPs can deliver antigen to both MHCI and MHCII antigen presentation pathways in primary DCs and promote cytotoxic and helper T cell priming despite their suppressive effect on pDCs.

  20. The gene corresponding to the putative Goodpasture antigen is present in Alport's syndrome.

    PubMed Central

    Savige, J A

    1991-01-01

    Alport's syndrome is a heterogeneous group of inherited abnormalities of basement membranes that may result in progressive renal failure, defective hearing and lens abnormalities. The glomerular basement membrane (GBM) characteristically has areas of reduplication, lamellation and attenuation on electron microscopic examination. In the majority of affected males and some females, there is reduced or variable binding of serum from patients with anti-GBM disease (Goodpasture's syndrome) to these basement membranes. These sera contain antibodies directed against the Goodpasture antigen which has been thought to be located in the non-collagenous domain of the alpha3 chain of type IV collagen and is presumed to be important in cross-linking of the collagen molecules. The reduced staining for the Goodpasture antigen suggests that this structure is either absent or masked in Alport's syndrome. We have tested DNA from six unrelated individuals with Alport's syndrome. All had been transplanted for renal failure. The diagnosis of Alport's syndrome was made on the characteristic electron microscopic appearance of the renal basement membranes (n = 4), the presence of sensori-neural deafness (n = 4), a family history of Alport's syndrome (n = 5) and the presence of circulating inhibitable anti-GBM antibody activity post-transplant (n = 2). Oligonucleotides (20mers) corresponding to the 5' and 3' ends of the known 25 amino acid sequence for the putative Goodpasture antigen were used as primers for amplification of genomic DNA. The products were then blotted and probed with an intermediate 19-mer DNA. All Alport's patients contained a 75-bp fragment corresponding to the published peptide sequence for the non-collagenous domain of the alpha 3 chain of type IV collagen, suggesting that a large deletion of this region, the putative Goodpasture antigen, is unlikely to account for the defect in Alport's syndrome. Images Fig. 2 PMID:1864003

  1. The gene corresponding to the putative Goodpasture antigen is present in Alport's syndrome.

    PubMed

    Savige, J A

    1991-08-01

    Alport's syndrome is a heterogeneous group of inherited abnormalities of basement membranes that may result in progressive renal failure, defective hearing and lens abnormalities. The glomerular basement membrane (GBM) characteristically has areas of reduplication, lamellation and attenuation on electron microscopic examination. In the majority of affected males and some females, there is reduced or variable binding of serum from patients with anti-GBM disease (Goodpasture's syndrome) to these basement membranes. These sera contain antibodies directed against the Goodpasture antigen which has been thought to be located in the non-collagenous domain of the alpha3 chain of type IV collagen and is presumed to be important in cross-linking of the collagen molecules. The reduced staining for the Goodpasture antigen suggests that this structure is either absent or masked in Alport's syndrome. We have tested DNA from six unrelated individuals with Alport's syndrome. All had been transplanted for renal failure. The diagnosis of Alport's syndrome was made on the characteristic electron microscopic appearance of the renal basement membranes (n = 4), the presence of sensori-neural deafness (n = 4), a family history of Alport's syndrome (n = 5) and the presence of circulating inhibitable anti-GBM antibody activity post-transplant (n = 2). Oligonucleotides (20mers) corresponding to the 5' and 3' ends of the known 25 amino acid sequence for the putative Goodpasture antigen were used as primers for amplification of genomic DNA. The products were then blotted and probed with an intermediate 19-mer DNA. All Alport's patients contained a 75-bp fragment corresponding to the published peptide sequence for the non-collagenous domain of the alpha 3 chain of type IV collagen, suggesting that a large deletion of this region, the putative Goodpasture antigen, is unlikely to account for the defect in Alport's syndrome.

  2. Detection of rare antigen-presenting cells through T cell-intrinsic meandering motility, mediated by Myo1g.

    PubMed

    Gérard, Audrey; Patino-Lopez, Genaro; Beemiller, Peter; Nambiar, Rajalakshmi; Ben-Aissa, Khadija; Liu, Yin; Totah, Fadi J; Tyska, Matthew J; Shaw, Stephen; Krummel, Matthew F

    2014-07-31

    To mount an immune response, T lymphocytes must successfully search for foreign material bound to the surface of antigen-presenting cells. How T cells optimize their chances of encountering and responding to these antigens is unknown. T cell motility in tissues resembles a random or Levy walk and is regulated in part by external factors including chemokines and lymph-node topology, but motility parameters such as speed and propensity to turn may also be cell intrinsic. Here we found that the unconventional myosin 1g (Myo1g) motor generates membrane tension, enforces cell-intrinsic meandering search, and enhances T-DC interactions during lymph-node surveillance. Increased turning and meandering motility, as opposed to ballistic motility, is enhanced by Myo1g. Myo1g acts as a "turning motor" and generates a form of cellular "flânerie." Modeling and antigen challenges show that these intrinsically programmed elements of motility search are critical for the detection of rare cognate antigen-presenting cells.

  3. Luciferase mRNA Transfection of Antigen Presenting Cells Permits Sensitive Nonradioactive Measurement of Cellular and Humoral Cytotoxicity

    PubMed Central

    Omokoko, Tana A.; Luxemburger, Uli; Bardissi, Shaheer; Simon, Petra; Utsch, Magdalena; Breitkreuz, Andrea; Türeci, Özlem; Sahin, Ugur

    2016-01-01

    Immunotherapy is rapidly evolving as an effective treatment option for many cancers. With the emerging fields of cancer vaccines and adoptive cell transfer therapies, there is an increasing demand for high-throughput in vitro cytotoxicity assays that efficiently analyze immune effector functions. The gold standard 51Cr-release assay is very accurate but has the major disadvantage of being radioactive. We reveal the development of a versatile and nonradioactive firefly luciferase in vitro transcribed (IVT) RNA-based assay. Demonstrating high efficiency, consistency, and excellent target cell viability, our optimized luciferase IVT RNA is used to transfect dividing and nondividing primary antigen presenting cells. Together with the long-lasting expression and minimal background, the direct measurement of intracellular luciferase activity of living cells allows for the monitoring of killing kinetics and displays paramount sensitivity. The ability to cotransfect the IVT RNA of the luciferase reporter and the antigen of interest into the antigen presenting cells and its simple read-out procedure render the assay high-throughput in nature. Results generated were comparable to the 51Cr release and further confirmed the assay's ability to measure antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity. The assay's combined simplicity, practicality, and efficiency tailor it for the analysis of antigen-specific cellular and humoral effector functions during the development of novel immunotherapies. PMID:27057556

  4. B cell antigen presentation is sufficient to drive neuro-inflammation in an animal model of multiple sclerosis1

    PubMed Central

    Parker Harp, Chelsea R.; Archambault, Angela S.; Sim, Julia; Ferris, Stephen T.; Mikesell, Robert J.; Koni, Pandelakis A.; Shimoda, Michiko; Linington, Christopher; Russell, John H.; Wu, Gregory F.

    2015-01-01

    B cells are increasingly regarded as integral to the pathogenesis of multiple sclerosis (MS) in part due to the success of B cell depletion therapy. Multiple B cell-dependent mechanisms contributing to inflammatory demyelination of the central nervous system (CNS) have been explored using experimental autoimmune encephalomyelitis (EAE), a CD4 T cell-dependent animal model for multiple sclerosis (MS). While B cell antigen presentation has been suggested to regulate CNS inflammation during EAE, direct evidence that B cells can independently support antigen-specific autoimmune responses by CD4 T cells in EAE is lacking. Using a newly developed murine model of in vivo conditional expression of MHCII, we previously reported that encephalitogenic CD4 T cells are incapable of inducing EAE when B cells are the sole antigen presenting cell. Herein we find that B cells cooperate with dendritic cells to enhance EAE severity resulting from myelin oligodendrocyte glycoprotein (MOG) immunization. Further, increasing the precursor frequency of MOG-specific B cells, but not addition of soluble MOG-specific antibody, is sufficient to drive EAE in mice expressing MHCII by B cells alone. These data support a model in which expansion of antigen-specific B cells during CNS autoimmunity amplifies cognate interactions between B and CD4 T cells and have the capacity to independently drive neuro-inflammation at later stages of disease. PMID:25895531

  5. Increased endogenous antigen presentation in the periphery enhances susceptibility to inflammation-induced gastric autoimmunity in mice.

    PubMed

    Overall, Sarah A; Bourges, Dorothée; van Driel, Ian R; Gleeson, Paul A

    2017-01-01

    How the immune system maintains peripheral tolerance under inflammatory conditions is poorly understood. Here we assessed the fate of gastritogenic T cells following inflammatory activation in vivo. Self-reactive T cells (A23 T cells) specific for the gastric H(+) /K(+) ATPase α subunit (HKα) were transferred into immunosufficient recipient mice and immunised at a site distant to the stomach with adjuvant containing the cognate HKα peptide antigen. Activation of A23 T cells by immunisation did not impact on either immune tolerance or protection from gastric autoimmunity in wild-type BALB/c mice. However, increased presentation of endogenously derived HKα epitopes by dendritic cells (DCs) in the gastric lymph node of IE-H(+) /K(+) β transgenic mice (IEβ) reduces A23 T-cell tolerance to gastric antigens after inflammatory activation, with subsequent development of gastritis. While HKα-specific A23 T cells from immunised wild-type mice were poorly responsive to in vitro antigen specific activation, A23 T cells from immunised IEβ transgenic mice were readily re-activated, indicating loss of T-cell anergy. These findings show that DCs of gastric lymph nodes can maintain tolerance of pathogenic T cells following inflammatory stimulation and that the density of endogenous antigen presented to self-reactive T cells is critical in the balance between tolerance and autoimmunity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Intestinal antigen-presenting cells in mucosal immune homeostasis: crosstalk between dendritic cells, macrophages and B-cells.

    PubMed

    Mann, Elizabeth R; Li, Xuhang

    2014-08-07

    The intestinal immune system maintains a delicate balance between immunogenicity against invading pathogens and tolerance of the commensal microbiota. Inflammatory bowel disease (IBD) involves a breakdown in tolerance towards the microbiota. Dendritic cells (DC), macrophages (MΦ) and B-cells are known as professional antigen-presenting cells (APC) due to their specialization in presenting processed antigen to T-cells, and in turn shaping types of T-cell responses generated. Intestinal DC are migratory cells, unique in their ability to generate primary T-cell responses in mesenteric lymph nodes or Peyer's patches, whilst MΦ and B-cells contribute to polarization and differentiation of secondary T-cell responses in the gut lamina propria. The antigen-sampling function of gut DC and MΦ enables them to sample bacterial antigens from the gut lumen to determine types of T-cell responses generated. The primary function of intestinal B-cells involves their secretion of large amounts of immunoglobulin A, which in turn contributes to epithelial barrier function and limits immune responses towards to microbiota. Here, we review the role of all three types of APC in intestinal immunity, both in the steady state and in inflammation, and how these cells interact with one another, as well as with the intestinal microenvironment, to shape mucosal immune responses. We describe mechanisms of maintaining intestinal immune tolerance in the steady state but also inappropriate responses of APC to components of the gut microbiota that contribute to pathology in IBD.

  7. Intestinal antigen-presenting cells in mucosal immune homeostasis: Crosstalk between dendritic cells, macrophages and B-cells

    PubMed Central

    Mann, Elizabeth R; Li, Xuhang

    2014-01-01

    The intestinal immune system maintains a delicate balance between immunogenicity against invading pathogens and tolerance of the commensal microbiota. Inflammatory bowel disease (IBD) involves a breakdown in tolerance towards the microbiota. Dendritic cells (DC), macrophages (MΦ) and B-cells are known as professional antigen-presenting cells (APC) due to their specialization in presenting processed antigen to T-cells, and in turn shaping types of T-cell responses generated. Intestinal DC are migratory cells, unique in their ability to generate primary T-cell responses in mesenteric lymph nodes or Peyer’s patches, whilst MΦ and B-cells contribute to polarization and differentiation of secondary T-cell responses in the gut lamina propria. The antigen-sampling function of gut DC and MΦ enables them to sample bacterial antigens from the gut lumen to determine types of T-cell responses generated. The primary function of intestinal B-cells involves their secretion of large amounts of immunoglobulin A, which in turn contributes to epithelial barrier function and limits immune responses towards to microbiota. Here, we review the role of all three types of APC in intestinal immunity, both in the steady state and in inflammation, and how these cells interact with one another, as well as with the intestinal microenvironment, to shape mucosal immune responses. We describe mechanisms of maintaining intestinal immune tolerance in the steady state but also inappropriate responses of APC to components of the gut microbiota that contribute to pathology in IBD. PMID:25110405

  8. Synthesis of protein-loaded hydrogel particles in an aqueous two-phase system for coincident antigen and CpG oligonucleotide delivery to antigen-presenting cells.

    PubMed

    Jain, Siddhartha; Yap, Woon Teck; Irvine, Darrell J

    2005-01-01

    Materials that effectively deliver protein antigens together with activating ligands to antigen-presenting cells are sought for improved nonviral vaccines. To this end, we synthesized protein-loaded poly(ethylene glycol) (PEG)-based hydrogel particles by cross-linking PEG within the polymer-rich phase of an emulsion formed by a poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) triblock copolymer in saturated aqueous salt solution. These particles (500-nm diameter) contained high levels of encapsulated protein (approximately 75% of dry mass), which was selectively released by proteolytic enzymes normally present in the phagosomal/endosomal compartments of dendritic cells (DCs). For co-delivery of cellular activation signals, gel particles were surface-modified by sequential adsorption of poly(l-arginine) and CpG oligonucleotides. DCs pulsed with protein-loaded particles activated naïve T cells in vitro approximately 10-fold more efficiently than DCs incubated with soluble protein. This organic solvent-free strategy for protein encapsulation within submicron-sized hydrophilic particles is attractive for macromolecule delivery to a variety of phagocytic and nonphagocytic cells.

  9. Sialic acid removal from dendritic cells improves antigen cross-presentation and boosts anti-tumor immune responses

    PubMed Central

    Silva, Mariana; Silva, Zélia; Marques, Graça; Ferro, Tiago; Gonçalves, Márcia; Monteiro, Mauro; van Vliet, Sandra J.; Mohr, Elodie; Lino, Andreia C.; Fernandes, Alexandra R.; Lima, Flávia A.; van Kooyk, Yvette; Matos, Teresa; Tadokoro, Carlos E.; Videira, Paula A.

    2016-01-01

    Dendritic cells (DCs) hold promise for anti-cancer immunotherapy. However, clinically, their efficiency is limited and novel strategies to improve DC-mediated anti-tumor responses are needed. Human DCs display high content of sialic acids, which inhibits their maturation and co-stimulation capacity. Here, we aimed to understand whether exogenous desialylation of DCs improves their anti-tumor immunity. Compared to fully sialylated DCs, desialylated human DCs loaded with tumor-antigens showed enhanced ability to induce autologous T cells to proliferate, to secrete Th1 cytokines, and to specifically induce tumor cell apoptosis. Desialylated DCs showed an increased expression of MHC-I and -II, co-stimulatory molecules and an augmented secretion of IL-12. Desialylated HLA-A*02:01 DCs pulsed with gp100 peptides displayed enhanced peptide presentation through MHC-I, resulting in higher activation ofgp100280–288 specific CD8+ cytotoxic T cells. Desialylated murine DCs also exhibited increased MHC and co-stimulatory molecules and higher antigen cross-presentation via MHC-I. These DCs showed higher ability to activate antigen-specific CD4+ and CD8+ T cells, and to specifically induce tumor cell apoptosis. Collectively, our data demonstrates that desialylation improves DCs' ability to elicit T cell-mediated anti-tumor activity, due to increased MHC-I expression and higher antigen presentation via MHC-I. Sialidase treatment of DCs may represent a technology to improve the efficacy of antigen loaded-DC-based vaccines for anti-cancer immunotherapy. PMID:27203391

  10. Sialic acid removal from dendritic cells improves antigen cross-presentation and boosts anti-tumor immune responses.

    PubMed

    Silva, Mariana; Silva, Zélia; Marques, Graça; Ferro, Tiago; Gonçalves, Márcia; Monteiro, Mauro; van Vliet, Sandra J; Mohr, Elodie; Lino, Andreia C; Fernandes, Alexandra R; Lima, Flávia A; van Kooyk, Yvette; Matos, Teresa; Tadokoro, Carlos E; Videira, Paula A

    2016-07-05

    Dendritic cells (DCs) hold promise for anti-cancer immunotherapy. However, clinically, their efficiency is limited and novel strategies to improve DC-mediated anti-tumor responses are needed. Human DCs display high content of sialic acids, which inhibits their maturation and co-stimulation capacity. Here, we aimed to understand whether exogenous desialylation of DCs improves their anti-tumor immunity. Compared to fully sialylated DCs, desialylated human DCs loaded with tumor-antigens showed enhanced ability to induce autologous T cells to proliferate, to secrete Th1 cytokines, and to specifically induce tumor cell apoptosis. Desialylated DCs showed an increased expression of MHC-I and -II, co-stimulatory molecules and an augmented secretion of IL-12. Desialylated HLA-A*02:01 DCs pulsed with gp100 peptides displayed enhanced peptide presentation through MHC-I, resulting in higher activation ofgp100280-288 specific CD8+ cytotoxic T cells. Desialylated murine DCs also exhibited increased MHC and co-stimulatory molecules and higher antigen cross-presentation via MHC-I. These DCs showed higher ability to activate antigen-specific CD4+ and CD8+ T cells, and to specifically induce tumor cell apoptosis. Collectively, our data demonstrates that desialylation improves DCs' ability to elicit T cell-mediated anti-tumor activity, due to increased MHC-I expression and higher antigen presentation via MHC-I. Sialidase treatment of DCs may represent a technology to improve the efficacy of antigen loaded-DC-based vaccines for anti-cancer immunotherapy.

  11. Present capabilities and new developments in antenna modeling with the numerical electromagnetics code NEC

    SciTech Connect

    Burke, G.J.

    1988-04-08

    Computer modeling of antennas, since its start in the late 1960's, has become a powerful and widely used tool for antenna design. Computer codes have been developed based on the Method-of-Moments, Geometrical Theory of Diffraction, or integration of Maxwell's equations. Of such tools, the Numerical Electromagnetics Code-Method of Moments (NEC) has become one of the most widely used codes for modeling resonant sized antennas. There are several reasons for this including the systematic updating and extension of its capabilities, extensive user-oriented documentation and accessibility of its developers for user assistance. The result is that there are estimated to be several hundred users of various versions of NEC world wide. 23 refs., 10 figs.

  12. Effect of oestradiol and pathogen-associated molecular patterns on class II-mediated antigen presentation and immunomodulatory molecule expression in the mouse female reproductive tract

    PubMed Central

    Ochiel, Daniel O; Rossoll, Richard M; Schaefer, Todd M; Wira, Charles R

    2012-01-01

    Cells of the female reproductive tract (FRT) can present antigen to naive and memory T cells. However, the effects of oestrogen, known to modulate immune responses, on antigen presentation in the FRT remain undefined. In the present study, DO11.10 T-cell antigen receptor transgenic mice specific for the class II MHC-restricted ovalbumin (OVA) 323–339 peptide were used to study the effects of oestradiol and pathogen-associated molecular patterns on antigen presentation in the FRT. We report here that oestradiol inhibited antigen presentation of OVA by uterine epithelial cells, uterine stromal cells and vaginal cells to OVA-specific memory T cells. When ovariectomized animals were treated with oestradiol for 1 or 3 days, antigen presentation was decreased by 20–80%. In contrast, incubation with PAMP increased antigen presentation by epithelial cells (Pam3Cys), stromal cells (peptidoglycan, Pam3Cys) and vaginal cells (Pam3Cys). In contrast, CpG inhibited both stromal and vaginal cell antigen presentation. Analysis of mRNA expression by reverse transcription PCR indicated that oestradiol inhibited CD40, CD80 and class II in the uterus and CD40, CD86 and class II in the vagina. Expression in isolated uterine and vaginal cells paralleled that seen in whole tissues. In contrast, oestradiol increased polymeric immunoglobulin receptor mRNA expression in the uterus and decreased it in the vagina. These results indicate that antigen-presenting cells in the uterus and vagina are responsive to oestradiol, which inhibits antigen presentation and co-stimulatory molecule expression. Further, these findings suggest that antigen-presenting cells in the uterus and vagina respond to selected Toll-like receptor agonists with altered antigen presentation. PMID:22043860

  13. In vivo administration of artificial antigen-presenting cells activates low-avidity T cells for treatment of cancer.

    PubMed

    Ugel, Stefano; Zoso, Alessia; De Santo, Carmela; Li, Yu; Marigo, Ilaria; Zanovello, Paola; Scarselli, Elisa; Cipriani, Barbara; Oelke, Mathias; Schneck, Jonathan P; Bronte, Vincenzo

    2009-12-15

    The development of effective antitumor immune responses is normally constrained by low-avidity, tumor-specific CTLs that are unable to eradicate the tumor. Strategies to rescue antitumor activity of low-avidity melanoma-specific CTLs in vivo may improve immunotherapy efficacy. To boost the in vivo effectiveness of low-avidity CTLs, we immunized mice bearing lung melanoma metastases with artificial antigen-presenting cells (aAPC), made by covalently coupling (pep)MHC-Ig dimers and B7.1-Ig molecules to magnetic beads. aAPC treatment induced significant tumor reduction in a mouse telomerase antigen system, and complete tumor eradication in a mouse TRP-2 antigen system, when low-avidity CTLs specific for these antigens were adoptively transferred. In addition, in an in vivo treatment model of subcutaneous melanoma, aAPC injection also augmented the activity of adoptively transferred CTLs and significantly delayed tumor growth. In vivo tumor clearance due to aAPC administration correlated with in situ proliferation of the transferred CTL. In vitro studies showed that aAPC effectively stimulated cytokine release, enhanced CTL-mediated lysis, and TCR downregulation in low-avidity CTLs. Therefore, in vivo aAPC administration represents a potentially novel approach to improve cancer immunotherapy.

  14. Cordyceps militaris Enhances MHC-restricted Antigen Presentation via the Induced Expression of MHC Molecules and Production of Cytokines

    PubMed Central

    Shin, Seulmee; Park, Yoonhee; Kim, Seulah; Oh, Hee-Eun; Ko, Young-Wook; Han, Shinha; Lee, Seungjeong; Lee, Chong-Kil; Cho, Kyunghae

    2010-01-01

    Background Cordyceps militarys water extract (CME) has been reported to exert antitumor and immunomodulatory activities in vivo and in vitro. However, the therapeutic mechanism has not yet been elucidated. In this study, we examined the effects of CME on the antigen presenting function of antigen presenting cells (APCs). Methods Dendritic cells (DCs) were cultured in the presence of CME, and then allowed to phagocytose microspheres containing ovalbumin (OVA). After washing and fixing the efficacy of OVA, peptide presentation by DCs were evaluated using CD8 and CD4 T cells. Also, we confirmed the protein levels of proinflammatory cytokines through western blot analysis. Results CME enhanced both MHC class I and class II-restricted presentation of OVA in DCs. In addition, the expression of both MHC class I and II molecules was enhanced, but there was no changes in the phagocytic activity of exogenous OVA. Furthermore, CME induced the protein levels of iNOS, COX-2, proinflammatory cytokines, and nuclear p65 in a concentration-dependent manner, as determined by western blot. Conclusion These results provide an understanding of the mechanism of the immuno-enhancing activity of CME on the induction of MHC-restricted antigen presentation in relation to their actions on APCs. PMID:20844738

  15. Manufacture of Clinical-Grade CD19-Specific T Cells Stably Expressing Chimeric Antigen Receptor Using Sleeping Beauty System and Artificial Antigen Presenting Cells

    PubMed Central

    Singh, Harjeet; Figliola, Matthew J.; Dawson, Margaret J.; Olivares, Simon; Zhang, Ling; Yang, Ge; Maiti, Sourindra; Manuri, Pallavi; Senyukov, Vladimir; Jena, Bipulendu; Kebriaei, Partow; Champlin, Richard E.; Huls, Helen; Cooper, Laurence J. N.

    2013-01-01

    Adoptive transfer of T cells expressing a CD19-specific chimeric antigen receptor (CAR) is being evaluated in multiple clinical trials. Our current approach to adoptive immunotherapy is based on a second generation CAR (designated CD19RCD28) that signals through a CD28 and CD3-ζ endodomain. T cells are electroporated with DNA plasmids from the Sleeping Beauty (SB) transposon/transposase system to express this CAR. Stable integrants of genetically modified T cells can then be retrieved when co-cultured with designer artificial antigen presenting cells (aAPC) in the presence of interleukin (IL)-2 and 21. Here, we reveal how the platform technologies of SB-mediated transposition and CAR-dependent propagation on aAPC were adapted for human application. Indeed, we have initiated clinical trials in patients with high-risk B-lineage malignancies undergoing autologous and allogeneic hematopoietic stem-cell transplantation (HSCT). We describe the process to manufacture clinical grade CD19-specific T cells derived from healthy donors. Three validation runs were completed in compliance with current good manufacturing practice for Phase I/II trials demonstrating that by 28 days of co-culture on γ-irradiated aAPC ∼1010 T cells were produced of which >95% expressed CAR. These genetically modified and propagated T cells met all quality control testing and release criteria in support of infusion. PMID:23741305

  16. Enhancement of antigen acquisition by dendritic cells and MHC class II-restricted epitope presentation to CD4+ T cells using VP22 DNA vaccine vectors that promote intercellular spreading following initial transfection.

    PubMed

    Mwangi, Waithaka; Brown, Wendy C; Splitter, Gary A; Zhuang, Yan; Kegerreis, Kimberly; Palmer, Guy H

    2005-08-01

    Induction of immune responses against microbial antigens using DNA is an attractive strategy to mimic the immunity induced by live vaccines. Although DNA vaccines are efficacious in murine models, the requirement for multiple immunizations using high doses in outbred animals and humans has hindered deployment. This requirement is, in part, a result of poor vaccine spreading and suboptimal DC transfection efficiency. Incorporation of a signal that directs intercellular spreading of a DNA-encoded antigen is proposed to mimic live vaccine spreading and increase dendritic cell (DC) presentation. Bovine herpes virus 1 tegument protein, BVP22, is capable of trafficking to surrounding cells. To test the hypothesis that BVP22 enhances spreading and antigen presentation to CD4+ T cells, a DNA construct containing BVP22, fused in-frame to a sequence encoding a T cell epitope of Anaplasma marginale, was generated. A construct with reversed BVP22 sequence served as a negative control. Immunocytometric analysis of transfected primary keratinocytes, human embryonic kidney 293, COS-7, and Chinese hamster ovary cells showed that BVP22 enhanced intercellular spreading by > or = 150-fold. Flow cytometric analysis of antigen-presenting cells (APCs) positively selected from cocultures of transfected cells and APCs showed that 5% of test APCs were antigen-positive, compared with 0.6% of control APCs. Antigen-specific CD4+ T cell proliferation demonstrated that BVP22 enhanced DC antigen presentation by > or = 20-fold. This first report of the ability of BVP22 to increase DNA-encoded antigen acquisition by DCs and macrophages, with subsequent enhancement of major histocompatibility complex class II-restricted CD4+ T cell responses, supports incorporating a spreading motif in a DNA vaccine to target CD4+ T cell-dependent immunity in outbred animals.

  17. Increased migration of antigen presenting cells to newly-formed lymphatic vessels in transplanted kidneys by glycol-split heparin.

    PubMed

    Talsma, Ditmer T; Katta, Kirankumar; Boersema, Miriam; Adepu, Saritha; Naggi, Annamaria; Torri, Giangiacomo; Stegeman, Coen; Navis, Gerjan; van Goor, Harry; Hillebrands, Jan-Luuk; Yazdani, Saleh; van den Born, Jacob

    2017-01-01

    Chronic renal transplant dysfunction is characterized by loss of renal function and tissue remodeling, including chronic inflammation and lymph vessel formation. Proteoglycans are known for their chemokine presenting capacity. We hypothesize that interruption of the lymphatic chemokine-proteoglycan interaction interferes with the lymphatic outflow of leukocytes from the renal graft and might decrease the anti-graft allo-immune response. In a rat renal chronic transplant dysfunction model (female Dark-Agouti to male Wistar Furth), chemokines were profiled by qRT-PCR in microdissected tubulo-interstitial tissue. Disruption of lymphatic chemokine-proteoglycan interaction was studied by (non-anticoagulant) heparin-derived polysaccharides in vitro and in renal allografts. The renal allograft function was assessed by rise in plasma creatinine and urea. Within newly-formed lymph vessels of transplanted kidneys, numerous CD45+ leukocytes were found, mainly MHCII+, ED-1-, IDO-, HIS14-, CD103- antigen presenting cells, most likely representing a subset of dendritic cells. Treatment of transplanted rats with regular heparin and two different (non-)anticoagulant heparin derivatives revealed worsening of kidney function only in the glycol-split heparin treated group despite a two-fold reduction of tubulo-interstitial leukocytes (p<0.02). Quantitative digital image analysis however revealed increased numbers of intra-lymphatic antigen-presenting cells only in the glycol-split heparin group (p<0.01). The number of intra-lymphatic leukocytes significantly correlates with plasma creatinine and urea, and inversely with creatinine clearance. Treatment of transplanted rats with glycol-split heparin significantly increases the number of intra-lymphatic antigen presenting cells, by increased renal diffusion of lymphatic chemokines, thereby increasing the activation and recruitment of antigen presenting cells towards the lymph vessel. This effect is unwanted in the transplantation

  18. Increased migration of antigen presenting cells to newly-formed lymphatic vessels in transplanted kidneys by glycol-split heparin

    PubMed Central

    Katta, Kirankumar; Boersema, Miriam; Adepu, Saritha; Naggi, Annamaria; Torri, Giangiacomo; Stegeman, Coen; Navis, Gerjan; van Goor, Harry; Hillebrands, Jan-Luuk; Yazdani, Saleh; van den Born, Jacob

    2017-01-01

    Background Chronic renal transplant dysfunction is characterized by loss of renal function and tissue remodeling, including chronic inflammation and lymph vessel formation. Proteoglycans are known for their chemokine presenting capacity. We hypothesize that interruption of the lymphatic chemokine–proteoglycan interaction interferes with the lymphatic outflow of leukocytes from the renal graft and might decrease the anti-graft allo-immune response. Methods In a rat renal chronic transplant dysfunction model (female Dark-Agouti to male Wistar Furth), chemokines were profiled by qRT-PCR in microdissected tubulo-interstitial tissue. Disruption of lymphatic chemokine–proteoglycan interaction was studied by (non-anticoagulant) heparin-derived polysaccharides in vitro and in renal allografts. The renal allograft function was assessed by rise in plasma creatinine and urea. Results Within newly-formed lymph vessels of transplanted kidneys, numerous CD45+ leukocytes were found, mainly MHCII+, ED-1-, IDO-, HIS14-, CD103- antigen presenting cells, most likely representing a subset of dendritic cells. Treatment of transplanted rats with regular heparin and two different (non-)anticoagulant heparin derivatives revealed worsening of kidney function only in the glycol-split heparin treated group despite a two-fold reduction of tubulo-interstitial leukocytes (p<0.02). Quantitative digital image analysis however revealed increased numbers of intra-lymphatic antigen-presenting cells only in the glycol-split heparin group (p<0.01). The number of intra-lymphatic leukocytes significantly correlates with plasma creatinine and urea, and inversely with creatinine clearance. Conclusions Treatment of transplanted rats with glycol-split heparin significantly increases the number of intra-lymphatic antigen presenting cells, by increased renal diffusion of lymphatic chemokines, thereby increasing the activation and recruitment of antigen presenting cells towards the lymph vessel. This

  19. Changes in the localization of antigen presenting cells and T cells in the utero-vaginal junction after repeated artificial insemination in laying hens.

    PubMed

    Das, Shubash Chandra; Nagasaka, Naohiro; Yoshimura, Yukinori

    2005-10-01

    The goal of our present study was to observe whether the populations of antigen presenting cells (Ia+ cells) and T cell subsets (CD4+ and CD8+ T cells) change in the utero-vaginal junction (UVJ) of Rhode Island Red laying hens that showed dramatic declines in fertility after repeated artificial insemination (AI). Rhode Island Red laying hens were divided into two groups: a virgin group (R-V) and artificial inseminated group (R-AI), which was exposed to weekly AI for a period of 3 mo. Undiluted fresh semen collected from healthy Tosa-Jidori roosters, a native Japanese breed maintained in Kochi Prefecture, was used for AI. The UVJ tissues were processed for frozen sections, and Ia+ cells and CD4+ and CD8+ T cells were identified by immunohistochemistry. The Ia+ cells and CD4+ and CD8+ T cells were observed in the stroma and mucosal epithelium of UVJ in both the R-AI and R-V birds. The frequencies of them in the stroma were significantly higher in R-AI than R-V. The higher frequency of Ia+ cells in the UVJ of R-AI group indicated a greater potential capability for antigen presentation to CD4+ cells. The significant increase in CD8+ and CD4+ T cells in the UVJ of R-AI birds might be the result of a homing process of lymphocytes, which may affect sperm survivability and fertility.

  20. Comparing Proteolytic Fingerprints of Antigen-Presenting Cells during Allergen Processing

    PubMed Central

    Hofer, Heidi; Weidinger, Tamara; Briza, Peter; Asam, Claudia; Wolf, Martin; Twaroch, Teresa E.; Stolz, Frank; Neubauer, Angela; Dall, Elfriede; Hammerl, Peter; Jacquet, Alain; Wallner, Michael

    2017-01-01

    Endolysosomal processing has a critical influence on immunogenicity as well as immune polarization of protein antigens. In industrialized countries, allergies affect around 25% of the population. For the rational design of protein-based allergy therapeutics for immunotherapy, a good knowledge of T cell-reactive regions on allergens is required. Thus, we sought to analyze endolysosomal degradation patterns of inhalant allergens. Four major allergens from ragweed, birch, as well as house dust mites were produced as recombinant proteins. Endolysosomal proteases were purified by differential centrifugation from dendritic cells, macrophages, and B cells, and combined with allergens for proteolytic processing. Thereafter, endolysosomal proteolysis was monitored by protein gel electrophoresis and mass spectrometry. We found that the overall proteolytic activity of specific endolysosomal fractions differed substantially, whereas the degradation patterns of the four model allergens obtained with the different proteases were extremely similar. Moreover, previously identified T cell epitopes were assigned to endolysosomal peptides and indeed showed a good overlap with known T cell epitopes for all four candidate allergens. Thus, we propose that the degradome assay can be used as a predictor to determine antigenic peptides as potential T cell epitopes, which will help in the rational design of protein-based allergy vaccine candidates. PMID:28594355

  1. Self-Antigen Presentation by Keratinocytes in the Inflamed Adult Skin Modulates T-Cell Auto-Reactivity.

    PubMed

    Meister, Michael; Tounsi, Amel; Gaffal, Evelyn; Bald, Tobias; Papatriantafyllou, Maria; Ludwig, Julia; Pougialis, Georg; Bestvater, Felix; Klotz, Luisa; Moldenhauer, Gerhard; Tüting, Thomas; Hämmerling, Günter J; Arnold, Bernd; Oelert, Thilo

    2015-08-01

    Keratinocytes have a pivotal role in the regulation of immune responses, but the impact of antigen presentation by these cells is still poorly understood, particularly in a situation where the antigen will be presented only in adult life. Here, we generated a transgenic mouse model in which keratinocytes exclusively present a myelin basic protein (MBP) peptide covalently linked to the major histocompatibility complex class II β-chain, solely under inflammatory conditions. In these mice, inflammation caused by epicutaneous contact sensitizer treatment resulted in keratinocyte-mediated expansion of MBP-specific CD4(+) T cells in the skin. Moreover, repeated contact sensitizer application preceding a systemic MBP immunization reduced the reactivity of the respective CD4(+) T cells and lowered the symptoms of the resulting experimental autoimmune encephalomyelitis. This downregulation was CD4(+) T-cell-mediated and dependent on the presence of the immune modulator Dickkopf-3. Thus, presentation of a neo self-antigen by keratinocytes in the inflamed, adult skin can modulate CD4(+) T-cell auto-aggression at a distal organ.

  2. A novel system of artificial antigen-presenting cells efficiently stimulates Flu peptide-specific cytotoxic T cells in vitro

    SciTech Connect

    Han, Hui; Peng, Ji-Run; Chen, Peng-Cheng; Gong, Lei; Qiao, Shi-Shi; Wang, Wen-Zhen; Cui, Zhu-Qingqing; Yu, Xin; Wei, Yu-Hua; Leng, Xi-Sheng

    2011-08-05

    Highlights: {yields} Adoptive immunotherapy depends on relevant numbers of cytolytic T lymphocytes. {yields} An ideal artificial APCs system was successfully prepared in vivo. {yields} Controlled release of IL-2 leads to much more T-cell expansion. {yields} This system is better than general cellular APCs on T-cell expansion. -- Abstract: Therapeutic numbers of antigen-specific cytotoxic T lymphocytes (CTLs) are key effectors in successful adoptive immunotherapy. However, efficient and reproducible methods to meet the qualification remain poor. To address this issue, we designed the artificial antigen-presenting cell (aAPC) system based on poly(lactic-co-glycolic acid) (PLGA). A modified emulsion method was used for the preparation of PLGA particles encapsulating interleukin-2 (IL-2). Biotinylated molecular ligands for recognition and co-stimulation of T cells were attached to the particle surface through the binding of avidin-biotin. These formed the aAPC system. The function of aAPCs in the proliferation of specific CTLs against human Flu antigen was detected by enzyme-linked immunospot assay (ELISPOT) and MTT staining methods. Finally, we successfully prepared this suitable aAPC system. The results show that IL-2 is released from aAPCs in a sustained manner over 30 days. This dramatically improves the stimulatory capacity of this system as compared to the effect of exogenous addition of cytokine. In addition, our aAPCs promote the proliferation of Flu antigen-specific CTLs more effectively than the autologous cellular APCs. Here, this aAPC platform is proved to be suitable for expansion of human antigen-specific T cells.

  3. Second-Generation Fuel Cell Stack Durability and Freeze Capability from National FCV Learning Demonstration (Presentation)

    SciTech Connect

    Wipke, K.; Sprik, S.; Kurtz, J.; Ramsden, T.; Garbak, J.

    2009-11-18

    This presentation provides information about the objectives and partners of the National Fuel Cell Vehicle Learning Demonstration, the status of vehicle and station deployment, and results of vehicle and infrastructure analysis.

  4. Probiotic metabolites from Bacillus coagulans GanedenBC30TM support maturation of antigen-presenting cells in vitro

    PubMed Central

    Benson, Kathleen F; Redman, Kimberlee A; Carter, Steve G; Keller, David; Farmer, Sean; Endres, John R; Jensen, Gitte S

    2012-01-01

    AIM: To study the effects of probiotic metabolites on maturation stage of antigen-presenting immune cells. METHODS: Ganeden Bacillus coagulans 30 (GBC30) bacterial cultures in log phase were used to isolate the secreted metabolite (MET) fraction. A second fraction was made to generate a crude cell-wall-enriched fraction, by centrifugation and lysis, followed by washing. A preparation of MET was subjected to size exclusion centrifugation, generating three fractions: < 3 kDa, 3-30 kDa, and 30-200 kDa and activities were tested in comparison to crude MET and cell wall in primary cultures of human peripheral blood mononuclear cell (PBMC) as a source of antigen-presenting mononuclear phagocytes. The maturation status of mononuclear phagocytes was evaluated by staining with monoclonal antibodies towards CD14, CD16, CD80 and CD86 and analyzed by flow cytometry. RESULTS: Treatment of PBMC with MET supported maturation of mononuclear phagocytes toward both macrophage and dendritic cell phenotypes. The biological activity unique to the metabolites included a reduction of CD14+ CD16+ pro-inflammatory cells, and this property was associated with the high molecular weight metabolite fraction. Changes were also seen for the dendritic cell maturation markers CD80 and CD86. On CD14dim cells, an increase in both CD80 and CD86 expression was seen, in contrast to a selective increase in CD86 expression on CD14bright cells. The co-expression of CD80 and CD86 indicates effective antigen presentation to T cells and support of T helper cell differentiation. The selective expression of CD86 in the absence of CD80 points to a role in generating T regulatory cells. CONCLUSION: The data show that a primary mechanism of action of GBC30 metabolites involves support of more mature phenotypes of antigen-presenting cells, important for immunological decision-making. PMID:22563167

  5. Robert Feulgen Prize Lecture 1995. Electronic light microscopy: present capabilities and future prospects.

    PubMed

    Shotton, D M

    1995-08-01

    Electronic light microscopy involves the combination of microscopic techniques with electronic imaging and digital image processing, resulting in dramatic improvements in image quality and ease of quantitative analysis. In this review, after a brief definition of digital images and a discussion of the sampling requirements for the accurate digital recording of optical images, I discuss the three most important imaging modalities in electronic light microscopy--video-enhanced contrast microscopy, digital fluorescence microscopy and confocal scanning microscopy--considering their capabilities, their applications, and recent developments that will increase their potential. Video-enhanced contrast microscopy permits the clear visualisation and real-time dynamic recording of minute objects such as microtubules, vesicles and colloidal gold particles, an order of magnitude smaller than the resolution limit of the light microscope. It has revolutionised the study of cellular motility, and permits the quantitative tracking of organelles and gold-labelled membrane bound proteins. In combination with the technique of optical trapping (optical tweezers), it permits exquisitely sensitive force and distance measurements to be made on motor proteins. Digital fluorescence microscopy enables low-light-level imaging of fluorescently labelled specimens. Recent progress has involved improvements in cameras, fluorescent probes and fluorescent filter sets, particularly multiple bandpass dichroic mirrors, and developments in multiparameter imaging, which is becoming particularly important for in situ hybridisation studies and automated image cytometry, fluorescence ratio imaging, and time-resolved fluorescence. As software improves and small computers become more powerful, computational techniques for out-of-focus blur deconvolution and image restoration are becoming increasingly important. Confocal microscopy permits convenient, high-resolution, non-invasive, blur-free optical

  6. Loss of Proliferation and Antigen Presentation Activity following Internalization of Polydispersed Carbon Nanotubes by Primary Lung Epithelial Cells

    PubMed Central

    Kumari, Mandavi; Sachar, Sumedha; Saxena, Rajiv K.

    2012-01-01

    Interactions between poly-dispersed acid functionalized single walled carbon nanotubes (AF-SWCNTs) and primary lung epithelial (PLE) cells were studied. Peritoneal macrophages (PMs, known phagocytic cells) were used as positive controls in this study. Recovery of live cells from cultures of PLE cells and PMs was significantly reduced in the presence of AF-SWCNTs, in a time and dose dependent manner. Both PLE cells as well as PMs could take up fluorescence tagged AF-SWCNTs in a time dependent manner and this uptake was significantly blocked by cytochalasin D, an agent that blocks the activity of acto-myosin fibers and therefore the phagocytic activity of cells. Confocal microscopic studies confirmed that AF-SWCNTs were internalized by both PLE cells and PMs. Intra-trachially instilled AF-SWCNTs could also be taken up by lung epithelial cells as well as alveolar macrophages. Freshly isolated PLE cells had significant cell division activity and cell cycling studies indicated that treatment with AF-SWCNTs resulted in a marked reduction in S-phase of the cell cycle. In a previously standardized system to study BCG antigen presentation by PLE cells and PMs to sensitized T helper cells, AF-SWCNTs could significantly lower the antigen presentation ability of both cell types. These results show that mouse primary lung epithelial cells can efficiently internalize AF-SWCNTs and the uptake of nanotubes interfered with biological functions of PLE cells including their ability to present BCG antigens to sensitized T helper cells. PMID:22384094

  7. Macrophage migration inhibitory factor protects from nonmelanoma epidermal tumors by regulating the number of antigen-presenting cells in skin.

    PubMed

    Brocks, Tania; Fedorchenko, Oleg; Schliermann, Nicola; Stein, Astrid; Moll, Ute M; Seegobin, Seth; Dewor, Manfred; Hallek, Michael; Marquardt, Yvonne; Fietkau, Katharina; Heise, Ruth; Huth, Sebastian; Pfister, Herbert; Bernhagen, Juergen; Bucala, Richard; Baron, Jens M; Fingerle-Rowson, Guenter

    2017-02-01

    The response of the skin to harmful environmental agents is shaped decisively by the status of the immune system. Keratinocytes constitutively express and secrete the chemokine-like mediator, macrophage migration inhibitory factor (MIF), more strongly than dermal fibroblasts, thereby creating a MIF gradient in skin. By using global and epidermis-restricted Mif-knockout (Mif(-/-) and K14-Cre(+/tg); Mif(fl/fl)) mice, we found that MIF both recruits and maintains antigen-presenting cells in the dermis/epidermis. The reduced presence of antigen-presenting cells in the absence of MIF was associated with accelerated and increased formation of nonmelanoma skin tumors during chemical carcinogenesis. Our results demonstrate that MIF is essential for maintaining innate immunity in skin. Loss of keratinocyte-derived MIF leads to a loss of control of epithelial skin tumor formation in chemical skin carcinogenesis, which highlights an unexpected tumor-suppressive activity of MIF in murine skin.-Brocks, T., Fedorchenko, O., Schliermann, N., Stein, A., Moll, U. M., Seegobin, S., Dewor, M., Hallek, M., Marquardt, Y., Fietkau, K., Heise, R., Huth, S., Pfister, H., Bernhagen, J., Bucala, R., Baron, J. M., Fingerle-Rowson, G. Macrophage migration inhibitory factor protects from nonmelanoma epidermal tumors by regulating the number of antigen-presenting cells in skin. © FASEB.

  8. Loss of proliferation and antigen presentation activity following internalization of polydispersed carbon nanotubes by primary lung epithelial cells.

    PubMed

    Kumari, Mandavi; Sachar, Sumedha; Saxena, Rajiv K

    2012-01-01

    Interactions between poly-dispersed acid functionalized single walled carbon nanotubes (AF-SWCNTs) and primary lung epithelial (PLE) cells were studied. Peritoneal macrophages (PMs, known phagocytic cells) were used as positive controls in this study. Recovery of live cells from cultures of PLE cells and PMs was significantly reduced in the presence of AF-SWCNTs, in a time and dose dependent manner. Both PLE cells as well as PMs could take up fluorescence tagged AF-SWCNTs in a time dependent manner and this uptake was significantly blocked by cytochalasin D, an agent that blocks the activity of acto-myosin fibers and therefore the phagocytic activity of cells. Confocal microscopic studies confirmed that AF-SWCNTs were internalized by both PLE cells and PMs. Intra-trachially instilled AF-SWCNTs could also be taken up by lung epithelial cells as well as alveolar macrophages. Freshly isolated PLE cells had significant cell division activity and cell cycling studies indicated that treatment with AF-SWCNTs resulted in a marked reduction in S-phase of the cell cycle. In a previously standardized system to study BCG antigen presentation by PLE cells and PMs to sensitized T helper cells, AF-SWCNTs could significantly lower the antigen presentation ability of both cell types. These results show that mouse primary lung epithelial cells can efficiently internalize AF-SWCNTs and the uptake of nanotubes interfered with biological functions of PLE cells including their ability to present BCG antigens to sensitized T helper cells.

  9. Usage of Murine T-cell Hybridoma Cells as Responder Cells Reveals Interference of Helicobacter Pylori with Human Dendritic Cell-mediated Antigen Presentation

    PubMed Central

    Fehlings, Michael; Drobbe, Lea; Beigier-Bompadre, Macarena; Viveros, Pablo Renner; Moos, Verena; Schneider, Thomas; Meyer, Thomas F.; Aebischer, Toni; Ignatius, Ralf

    2016-01-01

    Direct effects of Helicobacter pylori (H. pylori) on human CD4+ T-cells hamper disentangling a possible bacterial-mediated interference with major histocompatibility complex class II (MHC-II)-dependent antigen presentation to these cells. To overcome this limitation, we employed a previously described assay, which enables assessing human antigen-processing cell function by using murine T-cell hybridoma cells restricted by human leukocyte antigen (HLA) alleles. HLA-DR1+ monocyte-derived dendritic cells were exposed to H. pylori and pulsed with the antigen 85B from Mycobacterium tuberculosis (M. tuberculosis). Interleukin-2 (IL-2) secretion by AG85Baa97-112-specific hybridoma cells was then evaluated as an integral reporter of cognate antigen presentation. This methodology enabled revealing of interference of H. pylori with the antigen-presenting capacity of human dendritic cells. PMID:27980859

  10. Circulating follicular helper T cells presented distinctively different responses toward bacterial antigens in primary biliary cholangitis.

    PubMed

    Zhou, Zun-Qiang; Tong, Da-Nian; Guan, Jiao; Li, Mei-Fang; Feng, Qi-Ming; Zhou, Min-Jie; Zhang, Zheng-Yun

    2017-10-01

    Primary biliary cholangitis (PBC) is a chronic and progressive cholestatic liver disease with unknown causes. The initiation of PBC is associated with bacterial infections and abnormal immune correlates, such as the presence of self-reactive anti-mitochondrial antibodies and shifted balance of T cell subsets. In particular, the CD4(+)CXCR5(+) follicular helper T (Tfh) cells are highly activated in PBC patients and are significantly associated with PBC severity, but the underlying reasons are unknown. In this study, we found that the circulating CD4(+)CXCR5(+) T cells were enriched with the interferon (IFN)-γ-secreting Th1-subtype and the interleukin (IL)-17-secreting Th17-subtype, but not the IL-4-secreting Th2 subtype. We further demonstrated that a host of microbial motifs, including Pam3CSK4, poly(I:C), LPS, imiquimod, and CpG, could significantly stimulate IFN-γ, IL-17, and/or IL-21 from circulating CD4(+)CXCR5(+) T cells in PBC patients, especially in the presence of monocytes and B cells. Whole bacterial cells of Escherichia coli, Novosphingobium aromaticivorans, and Mycobacterium gordonae, could also potently stimulate IFN-γ, IL-17, and/or IL-21 production from circulating CD4(+)CXCR5(+) T cells. But interestingly, while the whole cell could potently stimulate circulating CD4(+)CXCR5(+) T cells from both healthy controls and PBC patients, the cell protein lysate could only potently stimulate circulating CD4(+)CXCR5(+) T cells from PBC patients, but not those from healthy controls, suggesting that circulating CD4(+)CXCR5(+) T cells in PBC patients had distinctive antigen-specificity from those in healthy individuals. Together, these data demonstrated that bacterial antigen stimulation is a potential source of aberrant Tfh cell activation in PBC patients. Copyright © 2017. Published by Elsevier B.V.

  11. Interference with PD-L1/PD-1 co-stimulation during antigen presentation enhances the multifunctionality of antigen-specific T cells.

    PubMed

    Pen, J J; Keersmaecker, B D; Heirman, C; Corthals, J; Liechtenstein, T; Escors, D; Thielemans, K; Breckpot, K

    2014-03-01

    The release of cytokines by T cells strongly defines their functional activity in vivo. The ability to produce multiple cytokines has been associated with beneficial immune responses in cancer and infectious diseases, while their progressive loss is associated with T-cell exhaustion, senescence and anergy. Consequently, strategies that enhance the multifunctional status of T cells are a key for immunotherapy. Dendritic cells (DCs) are professional antigen presenting cells that regulate T-cell functions by providing positive and negative co-stimulatory signals. A key negative regulator of T-cell activity is provided by binding of programmed death-1 (PD-1) receptor on activated T cells, to its ligand PD-L1, expressed on DCs. We investigated the impact of interfering with PD-L1/PD-1 co-stimulation on the multifunctionality of T cells, by expression of the soluble extracellular part of PD-1 (sPD-1) or PD-L1 (sPD-L1) in human monocyte-derived DCs during antigen presentation. Expression, secretion and binding of these soluble molecules after mRNA electroporation were demonstrated. Modification of DCs with sPD-1 or sPD-L1 mRNA resulted in increased levels of the co-stimulatory molecule CD80 and a distinct cytokine profile, characterized by the secretion of IL-10 and TNF-α, respectively. Co-expression in DCs of sPD-1 and sPD-L1 with influenza virus nuclear protein 1 (Flu NP1) stimulated Flu NP1 memory T cells, with a significantly higher number of multifunctional T cells and increased cytokine secretion, while it did not induce regulatory T cells. These data provide a rationale for the inclusion of interfering sPD-1 or sPD-L1 in DC-based immunotherapeutic strategies.

  12. Epstein-Barr virus latent membrane protein 2A exacerbates experimental autoimmune encephalomyelitis and enhances antigen presentation function

    PubMed Central

    Chang, Rhoda A.; Miller, Stephen D.; Longnecker, Richard

    2012-01-01

    Multiple sclerosis (MS) is an inflammatory, autoimmune disease of the central nervous system. The cause of MS is still unknown but epidemiological and immunological studies have implicated Epstein-Barr virus (EBV), which infects B cells, as a possible etiological agent involved in disease. Of particular interest is EBV latent membrane protein 2A (LMP2A) because previous studies have demonstrated that LMP2A enhances the expansion and differentiation of B cells upon antigen stimulation, revealing a potential contribution of this protein in autoimmunity. Since B cells are thought to contribute to MS, we examined the role of LMP2A in the animal model experimental autoimmune encephalomyelitis (EAE). In this model, transgenic mice in which B cells express LMP2A show increased severity and incidence of disease. This difference was not due to lymphocyte recruitment into the CNS or differences in T cell activation, rather, we show that LMP2A enhances antigen presentation function. PMID:22616025

  13. Direct activation of antigen-presenting cells is required for CD8+ T-cell priming and tumor vaccination

    PubMed Central

    Kratky, Wolfgang; Reis e Sousa, Caetano; Oxenius, Annette; Spörri, Roman

    2011-01-01

    Successful priming of adaptive immune responses is crucially dependent on innate activation signals that convert resting antigen-presenting cells (APCs) into immunogenic ones. APCs expressing the relevant innate pattern recognition receptors can be directly activated by pathogen-associated molecular patterns (PAMPs) to become competent to prime T-cell responses. Alternatively, it has been suggested that APCs could be activated indirectly by proinflammatory mediators synthesized by PAMP-exposed cells. However, data obtained with CD4+ T cells suggest that inflammatory signals often cannot substitute for direct pattern recognition in APC activation for the priming of T helper responses. To test whether the same is true for CD8+ T cells, we studied cytotoxic T lymphocyte development in vitro and in mixed chimeric mice in which coexisting APCs can either present a preprocessed model antigen or directly recognize a given PAMP, but not both. We show that indirectly activated APCs promote antigen-specific proliferation of naïve CD8+ T cells but fail to support their survival and cytotoxic T lymphocyte differentiation. Furthermore, CD8+ T cells primed by indirectly activated APCs are unable to reject tumors. Thus, inflammation cannot substitute for direct recognition of single PAMPs in CD8+ T-cell priming. These findings have important practical implications for vaccine design, indicating that adjuvants must be judiciously chosen to trigger the relevant pattern recognition receptors in APCs. PMID:21987815

  14. The Novel Toll-Like Receptor 2 Agonist SUP3 Enhances Antigen Presentation and T Cell Activation by Dendritic Cells

    PubMed Central

    Guo, Xueheng; Wu, Ning; Shang, Yingli; Liu, Xin; Wu, Tao; Zhou, Yifan; Liu, Xin; Huang, Jiaoyan; Liao, Xuebin; Wu, Li

    2017-01-01

    Dendritic cells (DCs) are highly specialized antigen-presenting cells that play crucial roles in innate and adaptive immunity. Previous studies suggested that Toll-like receptor (TLR) agonists could be used as potential adjuvants, as activation of TLRs can boost DC-induced immune responses. TLR2 agonists have been shown to enhance DC-mediated immune responses. However, classical TLR2 agonists such as Pam3CSK4 are not stable enough in vivo, which limits their clinical applications. In this study, a novel structurally stable TLR2 agonist named SUP3 was designed. Functional analysis showed that SUP3 induced much stronger antitumor response than Pam3CSK4 by promoting cytotoxic T lymphocytes activation in vivo. This effect was achieved through the following mechanisms: SUP3 strongly enhanced the ability of antigen cross-presentation by DCs and subsequent T cell activation. SUP3 upregulated the expression of costimulatory molecules on DCs and increased antigen deposition in draining lymph nodes. More interestingly, SUP3 induced less amount of pro-inflammatory cytokine production in vivo compared to other TLR agonists such as lipopolysaccharide. Taken together, SUP3 could serve as a novel promising immune adjuvant in vaccine development and immune modulations. PMID:28270814

  15. Mycobacterium avium ssp. paratuberculosis recombinant heat shock protein 70 interaction with different bovine antigen-presenting cells.

    PubMed

    Langelaar, M F M; Hope, J C; Rutten, V P M G; Noordhuizen, J P T M; van Eden, W; Koets, A P

    2005-03-01

    Abstract Heat shock proteins (Hsp) can deliver antigen into the major histocompatibility complex class I presentation pathway of antigen-presenting cells (APC), a process called cross priming, thus stimulating antigen-specific CD8+ T-cell reactions. Hsp were shown to elicit proinflammatory responses in APC. Both processes require interaction of Hsp with APC via specific receptors. This study describes the interaction of recombinant Hsp70 (rHsp70) of Mycobacterium avium subspecies paratuberculosis with bovine peripheral blood mononuclear cells that was restricted to CD14+ cells. Characterized monocyte-derived macrophages, monocyte-derived dendritic cells (DC) and BoMac, an immortalized bovine macrophage cell line, were used to investigate the interaction of rHsp70 with different bovine APC. Saturation of immature DC with high concentrations of rHsp70 is demonstrated, and it was found that interaction of rHsp70 with DC was related to the maturation stage of the DC. Involvement of CD91 as a cellular receptor for rHsp70 was demonstrated; however, competition studies with immature DC demonstrated that other receptors exist on bovine APC. These data suggest that rHsp70-based vaccines may be useful for the successful immunization of cattle.

  16. Nuclear Models in FLUKA: Present Capabilities, Open Problems and Future Improvements

    SciTech Connect

    Ballarini, F.

    2004-10-19

    The nuclear reaction models embedded in the FLUKA code cover hadron, ion, photon and neutrino induced nuclear interactions from energies as low as few tens of MeV up to several tens of TeV. A short description of the main physics ingredients in the FLUKA nuclear models is given, with emphasis on the intermediate energy range and on ''exotic'' reactions. The treatment of electromagnetic dissociation as recently implemented in FLUKA is described. Examples of performances are presented for illustrative situations covering some of the most typical FLUKA applications.

  17. Development of a Highly Sensitive Bioluminescent Enzyme Immunoassay for Hepatitis B Virus Surface Antigen Capable of Detecting Divergent Mutants

    PubMed Central

    Takehara, Shizuka; Takahashi, Masaharu

    2013-01-01

    Hepatitis B virus (HBV) infections are sometimes overlooked when using commercial kits to measure hepatitis B virus surface antigen (HBsAg) due to their low sensitivities and reactivities to mutant strains of various genotypes. We developed an ultrasensitive bioluminescent enzyme immunoassay (BLEIA) for HBsAg using firefly luciferase, which is adaptable to a variety of HBsAg mutants, by combining four monoclonal antibodies with a polyclonal antibody against HBsAg. The measurement of seroconversion panels showed trace amounts of HBsAg during the early infection phase by the BLEIA because of its high sensitivity of 5 mIU/ml. The BLEIA detected HBsAg as early as did PCR in five of seven series and from 2.1 to 9.4 days earlier than commercial immunoassay methods. During the late infection phase, the BLEIA successfully detected HBsAg even 40 days after the disappearance of HBV DNA and the emergence of antibodies against HBsAg. The HBsAg BLEIA successfully detected all 13 recombinant HBsAg and 45 types of HBsAg mutants with various mutations within amino acids 90 to 164 in the S gene product. Some specimens had higher values determined by the BLEIA than those by a commercial chemiluminescent immunoassay; this suggests that such discrepancies were caused by the dissociation of preS1/preS2 peptides from the particle surface. With its highly sensitive detection of low-titer HBsAg, including various mutants, the HBsAg BLEIA is considered to be useful for the early diagnosis and prevention of HBV infection because of the shorter window of infection prior to detection, which facilitates early prediction of recurrence in HBV-infected individuals. PMID:23761660

  18. NLRC5 elicits antitumor immunity by enhancing processing and presentation of tumor antigens to CD8+ T lymphocytes

    PubMed Central

    Rodriguez, Galaxia M.; Bobbala, Diwakar; Serrano, Daniel; Mayhue, Marian; Champagne, Audrey; Saucier, Caroline; Steimle, Viktor; Kufer, Thomas A.; Menendez, Alfredo; Ramanathan, Sheela; Ilangumaran, Subburaj

    2016-01-01

    ABSTRACT Cancers can escape immunesurveillance by diminishing the expression of MHC class-I molecules (MHC-I) and components of the antigen-processing machinery (APM). Developing new approaches to reverse these defects could boost the efforts to restore antitumor immunity. Recent studies have shown that the expression of MHC-I and antigen-processing molecules is transcriptionally regulated by NOD-like receptor CARD domain containing 5 (NLRC5). To investigate whether NLRC5 could be used to improve tumor immunogenicity, we established stable lines of B16-F10 melanoma cells expressing NLRC5 (B16-5), the T cell co-stimulatory molecule CD80 (B16-CD80) or both (B16-5/80). Cells harboring NLRC5 constitutively expressed MHC-I and LMP2, LMP7 and TAP1 genes of the APM. The B16-5 cells efficiently presented the melanoma antigenic peptide gp10025–33 to Pmel-1 TCR transgenic CD8+ T cells and induced their proliferation. In the presence of CD80, B16-5 cells stimulated Pmel-1 cells even without the addition of gp100 peptide, indicating that NLRC5 facilitated the processing and presentation of endogenous tumor antigen. Upon subcutaneous implantation, B16-5 cells showed markedly reduced tumor growth in C57BL/6 hosts but not in immunodeficient hosts, indicating that the NLRC5-expressing tumor cells elicited antitumor immunity. Following intravenous injection, B16-5 and B16-5/80 cells formed fewer lung tumor foci compared to control cells. In mice depleted of CD8+ T cells, B16-5 cells formed large subcutaneous and lung tumors. Finally, immunization with irradiated B16-5 cells conferred protection against challenge by parental B16 cells. Collectively, our findings indicate that NLRC5 could be exploited to restore tumor immunogenicity and to stimulate protective antitumor immunity. PMID:27471621

  19. Prolonged antigen presentation by immune complex-binding dendritic cells programs the proliferative capacity of memory CD8 T cells.

    PubMed

    León, Beatriz; Ballesteros-Tato, André; Randall, Troy D; Lund, Frances E

    2014-07-28

    The commitment of naive CD8 T cells to effector or memory cell fates can occur after a single day of antigenic stimulation even though virus-derived antigens (Ags) are still presented by DCs long after acute infection is resolved. However, the effects of extended Ag presentation on CD8 T cells are undefined and the mechanisms that regulate prolonged Ag presentation are unknown. We showed that the sustained presentation of two different epitopes from influenza virus by DCs prevented the premature contraction of the primary virus-specific CD8 T cell response. Although prolonged Ag presentation did not alter the number of memory CD8 T cells that developed, it was essential for programming the capacity of these cells to proliferate, produce cytokines, and protect the host after secondary challenge. Importantly, prolonged Ag presentation by DCs was dependent on virus-specific, isotype-switched antibodies (Abs) that facilitated the capture and cross-presentation of viral Ags by FcγR-expressing DCs. Collectively, our results demonstrate that B cells and Abs can regulate the quality and functionality of a subset of antiviral CD8 T cell memory responses and do so by promoting sustained Ag presentation by DCs during the contraction phase of the primary T cell response.

  20. Anti-TNF monoclonal antibodies prevent haemorrhage-induced suppression of Kupffer cell antigen presentation and MHC class II antigen expression.

    PubMed Central

    Ertel, W; Morrison, M H; Ayala, A; Perrin, M M; Chaudry, I H

    1991-01-01

    Kupffer cells (KC), by virtue of their ability to present antigen (AP) and express major histocompatibility complex (MHC) class II antigen (Ia), play a pivotal role in the host defence system against invading micro-organisms. Although haemorrhagic shock depresses the above KC functions, it is not known whether increased KC tumour necrosis factor (TNF) production and elevated TNF plasma levels following haemorrhage are responsible for it. To study this, C3H/HeN mice were pretreated intraperitoneally with either anti-murine TNF antibody (anti-TNF Ab) or saline. Twenty hours later mice were bled and maintained at a mean blood pressure of 35 mmHg for 60 min followed by adequate fluid resuscitation. Two and 24 hr later, plasma was collected and KC were isolated. AP was measured by co-culturing KC with the D10.G4.1 Th cell clone. Ia expression was determined by direct immunofluorescence. Interleukin (IL)-1, IL-6 and TNF levels in KC supernatants and plasma were measured with bioassays or ELISA. Haemorrhage increased circulating TNF levels by 215% at 2 hr and by 76% at 24 hr (P less than 0.05), which was prevented by pretreatment with anti-TNF Ab. Haemorrhage-induced increase of circulating IL-6 was abolished (P less than 0.05) at 2 hr but not at 24 hr in the anti-TNF Ab group. The suppression of KC AP (P less than 0.05) and Ia expression (P less than 0.05) due to haemorrhage was attenuated (P less than 0.05) in anti-TNF Ab-treated mice at 2 and 24 hr and KC IL-1 and TNF synthesis was further (P less than 0.01) increased. These results indicate that TNF plays a critical role in the initiation and regulation of KC AP, Ia expression, and cytokine production following haemorrhage. PMID:1748476

  1. Lithography-based ceramic manufacture (LCM) of auxetic structures: present capabilities and challenges

    NASA Astrophysics Data System (ADS)

    Díaz Lantada, Andrés; de Blas Romero, Adrián; Schwentenwein, Martin; Jellinek, Christopher; Homa, Johannes

    2016-05-01

    Auxetic metamaterials are known for having a negative Poisson’s ratio (NPR) and for displaying the unexpected properties of lateral expansion when stretched and densification when compressed. Even though a wide set of micro-manufacturing resources have been used for the development of auxetic metamaterials and related devices, additional precision and an extension to other families of materials is needed for their industrial expansion. In addition, their manufacture using ceramic materials is still challenging. In this study we present a very promising approach for the development of auxetic metamaterials and devices based on the use of lithography-based ceramic manufacturing. The process stands out for its precision and complex three-dimensional geometries attainable, without the need of supporting structures, and for enabling the manufacture of ceramic auxetics with their geometry controlled from the design stage with micrometric precision. To our knowledge it represents the first example of application of this technology to the manufacture of auxetic geometries using ceramic materials. We have used a special three-dimensional auxetic design whose remarkable NPR has been previously highlighted.

  2. Nonspecific Presentation of a Multiloculated Prostatic Abscess After Transurethral Prostatic Biopsy for Elevated Prostate-specific Antigen Level

    PubMed Central

    Gandhi, Nilay M.; Lin, Joseph; Schaeffer, Edward

    2014-01-01

    Prostate postbiopsy infectious complications typically present in the form of prostatitis and uncommonly urosepsis. Prostatic abscesses are generally found after multiple bouts of prostatitis and are associated with a clinically septic picture requiring intensive care unit admission and resuscitation. We report the case of a 65-year-old man who presented with prostatic abscess in the setting of nonspecific urinary symptoms after transrectal ultrasonography–guided prostate biopsy. At 4-month follow-up, he is currently free of disease with undetectable prostate-specific antigen level and negative imaging. PMID:26958487

  3. Modulation of human natural killer T cell ligands on TLR-mediated antigen-presenting cell activation.

    PubMed

    Salio, Mariolina; Speak, Anneliese O; Shepherd, Dawn; Polzella, Paolo; Illarionov, Petr A; Veerapen, Natacha; Besra, Gurdyal S; Platt, Frances M; Cerundolo, Vincenzo

    2007-12-18

    Invariant natural killer T (iNKT) cells are a subset of nonconventional T cells recognizing endogenous and/or exogenous glycolipid antigens in the context of CD1d molecules. It remains unclear whether innate stimuli can modify the profile of endogenous lipids recognized by iNKT cells on the surface of antigen-presenting cells (APCs). We report that activation of human APCs by Toll-like receptor ligands (TLR-L) modulates the lipid biosynthetic pathway, resulting in enhanced recognition of CD1d-associated lipids by iNKT cells, as defined by IFN-gamma secretion. APC-derived soluble factors further increase CD1d-restricted iNKT cell activation. Finally, using soluble tetrameric iNKT T cell receptors (TCR) as a staining reagent, we demonstrate specific up-regulation of CD1d-bound ligand(s) on TLR-mediated APC maturation. The ability of innate stimuli to modulate the lipid profile of APCs resulting in iNKT cell activation and APC maturation underscores the role of iNKT cells in assisting priming of antigen-specific immune responses.

  4. Modulation of human natural killer T cell ligands on TLR-mediated antigen-presenting cell activation

    PubMed Central

    Salio, Mariolina; Speak, Anneliese O.; Shepherd, Dawn; Polzella, Paolo; Illarionov, Petr A.; Veerapen, Natacha; Besra, Gurdyal S.; Platt, Frances M.; Cerundolo, Vincenzo

    2007-01-01

    Invariant natural killer T (iNKT) cells are a subset of nonconventional T cells recognizing endogenous and/or exogenous glycolipid antigens in the context of CD1d molecules. It remains unclear whether innate stimuli can modify the profile of endogenous lipids recognized by iNKT cells on the surface of antigen-presenting cells (APCs). We report that activation of human APCs by Toll-like receptor ligands (TLR-L) modulates the lipid biosynthetic pathway, resulting in enhanced recognition of CD1d-associated lipids by iNKT cells, as defined by IFN-γ secretion. APC-derived soluble factors further increase CD1d-restricted iNKT cell activation. Finally, using soluble tetrameric iNKT T cell receptors (TCR) as a staining reagent, we demonstrate specific up-regulation of CD1d-bound ligand(s) on TLR-mediated APC maturation. The ability of innate stimuli to modulate the lipid profile of APCs resulting in iNKT cell activation and APC maturation underscores the role of iNKT cells in assisting priming of antigen-specific immune responses. PMID:18077358

  5. Circulating immune complexes of Hodgkin's disease contain an antigen that is present in Hodgkin and Reed-Sternberg cells.

    PubMed

    Bepler, G; Zhen, Q Y; Havemann, K

    1985-01-01

    Circulating immune complexes (CIC), isolated from the serum of a patient with Hodgkin's disease (HD) and from control serum (CS) of healthy adults, were used to generate heterologous antisera in rabbits. The antiserum directed against CIC from HD (AS-HD) and the antiserum directed against CIC from CS (AS-CS) were used to identify immunoglobulins, complement factors and alpha2-macroglobulin as immune complex components. After adsorbing both antisera with normal human sera, we found that the adsorbed AS-HD was immunoreactive with radio-labelled CIC from HD serum but not with radiolabelled CIC from CS. Sera of patients with different diseases and sera of healthy adults were assessed for the occurrence of this Hodgkin immune complex-associated antigen (HIC-Ag). The HIC-Ag was present in 37% (12/33) of sera from patients with HD, 8% (8/101) of sera from patients with nonmalignant diseases, and 0% (0/6) of sera from healthy adults. This antigen was equally distributed among HD patients with and without symptoms, but its occurrence correlated with an advanced clinical stage of the disease. Using the adsorbed AS-HD in the immunoperoxidase technique, we identified the HIC-Ag as a cytoplasmic antigen in Hodgkin and Reed-Sternberg cells; whereas, the adsorbed AS-CS did not reveal any staining. These data indicate the presence of an HIC-Ag in the sera of patients with HD and suggest that the adsorbed AS-HD might be useful for isolation and characterization of this antigen for future use as a tumour marker.

  6. Processing and MHC class II presentation of exogenous soluble antigen involving a proteasome-dependent cytosolic pathway in CD40-activated B cells.

    PubMed

    Becker, Hans Jiro; Kondo, Eisei; Shimabukuro-Vornhagen, Alexander; Theurich, Sebastian; von Bergwelt-Baildon, Michael S

    2016-08-01

    Activated B cells have the capacity to present antigen and induce immune responses as potent antigen-presenting cells (APCs). As in other APCs, antigen presentation by B cells involves antigen internalization, antigen processing, and peptide loading onto MHC molecules. However, while the mechanism of antigen processing has been studied extensively in other APCs, this pathway remains elusive in B cells. The aim of this study was to investigate the MHC class II processing pathway in CD40-activated B cells (CD40Bs), as a model for activated, antigen-presenting B cells. Using CMV pp65 as a model antigen, we evaluated processing and presentation of the CD4 + T-cell epitope 509-523 (K509) by human CD40Bs in ELISPOT assays. As expected, stimulation of specific CD4 + T-cell clones was attenuated after pretreatment of CD40Bs with inhibitors of classic class II pathway components. However, proteasome inhibitors such as epoxomicin limited antigen presentation as well. This suggests that the antigen is processed in a non-classical, cytosolic MHC class II pathway. Further experiments with truncated protein variants revealed involvement of the proteasome in processing of the N and C extensions of the epitope. Access to the cytosol was shown to be size dependent. Epoxomicin sensitivity exclusively in CD40B cells, but not in dendritic cells, suggests a novel processing mechanism unique to this APC. Our data suggest that B cells process antigen using a distinct, non-classical class II pathway.

  7. Influence of Endosomal Escape and Degradation of α-Galactosylceramide Loaded Liposomes on CD1d Antigen Presentation.

    PubMed

    Nakamura, Takashi; Kuroi, Moeka; Harashima, Hideyoshi

    2015-08-03

    Alpha-galactosylceramide (GC), a lipid antigen present on CD1d molecules, is a unique adjuvant that enables a strong antitumor effect to be induced via activation of natural killer T cells. We previously reported that a liposomal formulation of GC significantly enhanced GC presentation via CD1d and antitumor immunity. However, the influence of the intracellular fate of liposomes controlled by the lipid composition on GC presentation using GC-loaded liposomes (GC-Lip) remains unclear. In this study, we prepared a GC-Lip formulation by incorporating dioleoyl-phosphatidylethanolamine (DOPE)/cholesterol, egg phosphatidylcholine (EPC)/cholesterol, and distearoyl phosphocholine (DSPC)/cholesterol, and investigated the relationship between the intracellular trafficking of GC-Lip and GC presentation in antigen-presenting cells. When GC-Lip was prepared using DOPE, a fusogenic lipid, the endosomal escape of liposomes was enhanced, resulting in a decrease in GC presentation of CD1d, compared to the EPC based GC-Lip (EPC/GC-Lip). The stability of liposomes in endosomes/lysosomes had no influence on GC presentation. The DSPC based GC-Lip (DSPC/GC-Lip) induced GC presentation without any detectable degradation in liposomal structure, although the EPC/GC-Lip induced GC presentation with degradation of liposomal structure. The efficiency of GC presentation between EPC/GC-Lip and DSPC/GC-Lip was comparable. These GC presentations that were independent of the degradation of liposomes were dominated by saposins, sphingolipid activator proteins. Our findings reveal that GC presentation on CD1d from the fluid liposomes involves the action of saposins, regardless of whether liposome degradation occurs. This insight can be of use in terms of developing GC-Lip formulation for efficient GC presentation.

  8. Kinetics of adeno-associated virus serotype 2 (AAV2) and AAV8 capsid antigen presentation in vivo are identical.

    PubMed

    He, Yi; Weinberg, Marc S; Hirsch, Matt; Johnson, Mark C; Tisch, Roland; Samulski, R Jude; Li, Chengwen

    2013-05-01

    Adeno-associated viral (AAV) vectors 2 and 8 have been used in clinical trials for patients with hemophilia, and data suggest that the capsid-specific CD8⁺ T cell response has had a negative impact on therapeutic success. To date the pattern of capsid cross-presentation from AAV2 and AAV8 transduction in vivo has not been elucidated. Previously, we have demonstrated that an engineered AAV2 virus carrying the immune-dominant SIINFEKL peptide in the capsid backbone was indistinguishable from wild type with respect to titer, tropism, and the ability to induce capsid-specific CD8⁺ T cell responses in vivo. In this study, we used the same strategy to engineer an AAV8 vector and demonstrated that antigen from SIINFEKL peptide-integrated AAV8 capsid was effectively presented via either plasmid transfection or AAV8 transduction in vitro. The tissue tropism and transgene expression kinetics of the engineered AAV8 vector in vivo were identical to that of wild-type AAV8. Animal studies show that capsid antigen presentation from AAV transduction was dose dependent, and more importantly, the proliferation of capsid-specific CD8⁺ T cells had similar kinetics (detectable before 30 days and undetectable after 40 days) for both AAV2 and AAV8 vectors. Elucidation of the kinetics of capsid antigen presentation from AAV transduction by various serotypes provides new insight into the potential impact CD8⁺ T cells can have during clinical trials and may help with rational design of effective strategies to prevent capsid-specific CD8⁺ T cell-mediated elimination of AAV-transduced target cells.

  9. Reassessing the role of HLA-DRB3 T cell responses: Evidence for significant expression and complementary antigen presentation

    PubMed Central

    Faner, Rosa; James, Eddie; Huston, Laurie; Pujol-Borrel, Ricardo; Kwok, William W; Juan, Manel

    2010-01-01

    Summary In humans, several HLA-DRB loci (DRB1/3/4/5) encode diverse beta-chains which pair with alpha-chains to form DR molecules on the surface of APC. While DRB1 and DRB5 have been extensively studied, the role of DRB3/4 products of DR52/DR53 haplotypes has been largely neglected. To clarify the relative expression of DRB3, we quantified DRB3 mRNA levels in comparison with DRB1 mRNA from the same haplotype in both B cells and monocytes, observing quantitatively significant DRB3 synthesis. In CD19+ cells, DRB1*03/11/13 was 3.5-fold more abundant than DRB3, but in CD14+ this difference was only 2-fold. Monocytes also had lower overall levels of DR mRNA compared to B cells, which was confirmed by cell surface staining of DRB1 and DRB3. To evaluate the functional role of DRB3, tetramer-guided epitope mapping was used to detect T-cells against tetanus toxin and several influenza antigens presented by DRB3*0101/0202 or DRB1*03/11/13. None of the epitopes discovered were shared among any of the DR molecules. Quantitative assessment of DRB3-TT specific T-cells revealed that they are present at similar frequencies as those observed for DRB1. These results suggest that DRB3 plays a significant role in antigen-presentation with different epitopic preferences to DRB1. Therefore, DRB3, like DRB5, serves to extend and complement the peptide repertoire of DRB1 in antigen presentation. PMID:19830726

  10. Reassessing the role of HLA-DRB3 T-cell responses: evidence for significant expression and complementary antigen presentation.

    PubMed

    Faner, Rosa; James, Eddie; Huston, Laurie; Pujol-Borrel, Ricardo; Kwok, William W; Juan, Manel

    2010-01-01

    In humans, several HLA-DRB loci (DRB1/3/4/5) encode diverse beta-chains that pair with alpha-chains to form DR molecules on the surface of APC. While DRB1 and DRB5 have been extensively studied, the role of DRB3/4 products of DR52/DR53 haplotypes has been largely neglected. To clarify the relative expression of DRB3, we quantified DRB3 mRNA levels in comparison with DRB1 mRNA from the same haplotype in both B cells and monocytes, observing quantitatively significant DRB3 synthesis. In CD19+ cells, DRB1*03/11/13 was 3.5-fold more abundant than DRB3, but in CD14+ this difference was only two-fold. Monocytes also had lower overall levels of DR mRNA compared with B cells, which was confirmed by cell surface staining of DRB1 and DRB3. To evaluate the functional role of DRB3, tetramer-guided epitope mapping was used to detect T cells against tetanus toxin and several influenza antigens presented by DRB3*0101/0202 or DRB1*03/11/13. None of the epitopes discovered were shared among any of the DR molecules. Quantitative assessment of DRB3-tetanus toxin specific T cells revealed that they are present at similar frequencies as those observed for DRB1. These results suggest that DRB3 plays a significant role in antigen presentation with different epitopic preferences to DRB1. Therefore, DRB3, like DRB5, serves to extend and complement the peptide repertoire of DRB1 in antigen presentation.

  11. Type II and III Receptors for Immunoglobulin G (IgG) Control the Presentation of Different T Cell Epitopes from Single IgG-complexed Antigens

    PubMed Central

    Amigorena, Sebastian; Lankar, Danielle; Briken, Volker; Gapin, Laurent; Viguier, Mireille; Bonnerot, Christian

    1998-01-01

    T cell receptors on CD4+ lymphocytes recognize antigen-derived peptides presented by major histocompatibility complex (MHC) class II molecules. A very limited set of peptides among those that may potentially bind MHC class II is actually presented to T lymphocytes. We here examine the role of two receptors mediating antigen internalization by antigen presenting cells, type IIb2 and type III receptors for IgG (FcγRIIb2 and FcγRIII, respectively), in the selection of peptides for presentation to T lymphocytes. B lymphoma cells expressing recombinant FcγRIIb2 or FcγRIII were used to assess the presentation of several epitopes from two different antigens. 4 out of the 11 epitopes tested were efficiently presented after antigen internalization through FcγRIIb2 and FcγRIII. In contrast, the 7 other epitopes were efficiently presented only when antigens were internalized through FcγRIII, but not through FcγRIIb2. The capacity to present these latter epitopes was transferred to a tail-less FcγRIIb2 by addition of the FcγRIII-associated γ chain cytoplasmic tail. Mutation of a single leucine residue at position 35 of the γ chain cytoplasmic tail resulted in the selective loss of presentation of these epitopes. Therefore, the nature of the receptor that mediates internalization determines the selection of epitopes presented to T lymphocytes within single protein antigens. PMID:9463401

  12. Brucella suis prevents human dendritic cell maturation and antigen presentation through regulation of tumor necrosis factor alpha secretion.

    PubMed

    Billard, Elisabeth; Dornand, Jacques; Gross, Antoine

    2007-10-01

    Brucella is a facultative intracellular pathogen and the etiological agent of brucellosis. In some cases, human brucellosis results in a persistent infection that may reactivate years after the initial exposure. The mechanisms by which the parasite evades clearance by the immune response to chronically infect its host are unknown. We recently demonstrated that dendritic cells (DCs), which are critical components of adaptive immunity, are highly susceptible to Brucella infection and are a preferential niche for the development of the bacteria. Here, we report that in contrast to several intracellular bacteria, Brucella prevented the infected DCs from engaging in their maturation process and impaired their capacities to present antigen to naïve T cells and to secrete interleukin-12. Moreover, Brucella-infected DCs failed to release tumor necrosis factor alpha (TNF-alpha), a defect involving the bacterial protein Omp25. Exogenous TNF-alpha addition to Brucella-infected DCs restored cell maturation and allowed them to present antigens. Two avirulent mutants of B. suis, B. suis bvrR and B. suis omp25 mutants, which do not express the Omp25 protein, triggered TNF-alpha production upon DC invasion. Cells infected with these mutants subsequently matured and acquired the ability to present antigens, two properties which were dramatically impaired by addition of anti-TNF-alpha antibodies. In light of these data, we propose a model in which virulent Brucella alters the maturation and functions of DCs through Omp25-dependent control of TNF-alpha production. This model defines a specific evasion strategy of the bacteria by which they can escape the immune response to chronically infect their host.

  13. Dendritic cell directed CTLA-4 engagement during pancreatic β-cell antigen presentation delays type 1 diabetes1

    PubMed Central

    Karumuthil-Melethil, Subha; Perez, Nicolas; Li, Ruobing; Prabhakar, Bellur S.; Holterman, Mark J.; Vasu, Chenthamarakshan

    2010-01-01

    The levels of expression of alternatively spliced variants of CTLA-4 and insufficient CTLA-4 signaling have been implicated in type 1 diabetes (T1D). Hence, we hypothesized that increasing CTLA-4 specific ligand strength on autoantigen presenting dendritic cells (DCs) can enhance ligation of CTLA-4 on T cells and lead to modulation of autoreactive T cell response. In this study, we show that DC directed enhanced CTLA-4 engagement upon pancreatic β-cell antigen presentation results in the suppression of autoreactive T cell response in non-obese diabetic (NOD) mice. The T cells from pre-diabetic NOD mice treated with an agonistic anti-CTLA-4-Ab coated DCs showed significantly less proliferative response, and enhanced IL-10 and TGF-β1 production upon exposure to β-cell antigens. Furthermore, these mice showed increased frequency of Foxp3+ and IL-10+ T cells, less severe insulitis, and a significant delay in the onset of hyperglycemia compared to mice treated with a control-Ab coated DCs. Further analyses showed that diabetogenic T cell function was modulated primarily through the induction of Foxp3 and IL-10 expression upon antigen presentation by anti-CTLA-4-Ab coated DCs. The induction of Foxp3 and IL-10 expression appeared to be a consequence of increased TGF-β1 production by T cells activated using anti-CTLA-4 Ab coated DCs and this effect could be enhanced by the addition of exogenous IL-2 or TGF-β1. Collectively, this study demonstrates the potential of DC directed CTLA-4 engagement approach not only in treating autoimmunity in T1D, but also in altering diabetogenic T cell function ex vivo for therapy. PMID:20483724

  14. High-density lipoprotein affects antigen presentation by interfering with lipid raft: a promising anti-atherogenic strategy.

    PubMed

    Wang, S-H; Yuan, S-G; Peng, D-Q; Zhao, S-P

    2010-05-01

    Atherosclerosis is a chronic inflammatory disease. Immunomodulation of atherosclerosis emerges as a promising approach to prevention and treatment of this widely prevalent disease. The function of high-density lipoprotein (HDL) to promote reverse cholesterol transport may explain the ability of its protection against atherosclerosis. Findings that HDL and apolipoprotein A-I (apoA-I) inhibited the ability of antigen presenting cells (APCs) to stimulate T cells might be attributed to lipid raft, a cholesterol-rich microdomain exhibiting functional properties depending largely upon its lipid composition. Thus, modulating cholesterol in lipid raft may provide a promising anti-atherogenic strategy.

  15. The consequences of the intracellular retention of pathogen-derived T-cell-independent antigens on protein presentation to T cells.

    PubMed

    Leyva-Cobián, F; Outschoorn, I M; Carrasco-Marín, E; Alvarez-Domínguez, C

    1997-10-01

    Intracellular pathogens can be considered as particulate antigens chemically composed of a complex mixture of T-cell-dependent antigens (TD) (peptides and proteins) and T-cell-independent antigens (TI) (glycolipids and complex polysaccharides). A large range of saccharides (from oligosaccharides to complex polysaccharides) derived from pathogenic microorganisms are being isolated and characterized. They are currently implicated in signaling systems and concomitant host-parasite relationships. However, there are not many structure-function relationships described for these pathogens. This is particularly true of polysaccharides. In this report we have reviewed the role of defined TI antigens in the processing and presentation of defined TD antigens to specific T cells by antigen-presenting cells (APC). We also considered the importance of some of the chemical characteristics shared by different carbohydrates implicated in the inhibition of antigen presentation. These findings are discussed in relation to the clear immunopathological consequences of long retention periods of complex carbohydrate molecules derived from intracellular parasites inside certain APC and the absence of antigen presentation impairment in physiological situations such as the removal of senescent or damaged red blood cells by splenic macrophages or intracellular accumulation of carbohydrates in colostrum and milk macrophages during lactation.

  16. Recent advances in Major Histocompatibility Complex (MHC) class I antigen presentation: Plastic MHC molecules and TAPBPR-mediated quality control

    PubMed Central

    van Hateren, Andy; Bailey, Alistair; Elliott, Tim

    2017-01-01

    We have known since the late 1980s that the function of classical major histocompatibility complex (MHC) class I molecules is to bind peptides and display them at the cell surface to cytotoxic T cells. Recognition by these sentinels of the immune system can lead to the destruction of the presenting cell, thus protecting the host from pathogens and cancer. Classical MHC class I molecules (MHC I hereafter) are co-dominantly expressed, polygenic, and exceptionally polymorphic and have significant sequence diversity. Thus, in most species, there are many different MHC I allotypes expressed, each with different peptide-binding specificity, which can have a dramatic effect on disease outcome. Although MHC allotypes vary in their primary sequence, they share common tertiary and quaternary structures. Here, we review the evidence that, despite this commonality, polymorphic amino acid differences between allotypes alter the ability of MHC I molecules to change shape (that is, their conformational plasticity). We discuss how the peptide loading co-factor tapasin might modify this plasticity to augment peptide loading. Lastly, we consider recent findings concerning the functions of the non-classical MHC I molecule HLA-E as well as the tapasin-related protein TAPBPR (transporter associated with antigen presentation binding protein-related), which has been shown to act as a second quality-control stage in MHC I antigen presentation. PMID:28299193

  17. Microbe-specific unconventional T-cells induce human neutrophil differentiation into antigen cross-presenting cells

    PubMed Central

    Liuzzi, Anna Rita; Tyler, Christopher J.; Khan, Mohd Wajid A.; Szakmany, Tamas; Hall, Judith E.; Moser, Bernhard; Eberl, Matthias

    2014-01-01

    The early immune response to microbes is dominated by the recruitment of neutrophils whose primary function is to clear invading pathogens. However, there is emerging evidence that neutrophils play additional effector and regulatory roles. The present study demonstrates that human neutrophils assume antigen cross-presenting functions, and suggests a plausible scenario for the local generation of APC-like neutrophils through the mobilization of unconventional T-cells in response to microbial metabolites. Vγ9/Vδ2 T-cells and MAIT cells are abundant in blood, inflamed tissues and mucosal barriers. Here, both human cell types responded rapidly to neutrophils after phagocytosis of Gram-positive and Gram-negative bacteria producing the corresponding ligands, and in turn mediated the differentiation of neutrophils into APCs for both CD4+ and CD8+ T-cells through secretion of GM-CSF, IFN-γ and TNF-α. In patients with acute sepsis, circulating neutrophils displayed a similar APC-like phenotype and readily processed soluble proteins for cross-presentation of antigenic peptides to CD8+ T-cells, at a time when peripheral Vγ9/Vδ2 T-cells were highly activated. Our findings indicate that unconventional T-cells represent key controllers of neutrophil-driven innate and adaptive responses to a broad range of pathogens. PMID:25165152

  18. Recruitment of bone marrow CD11b+Gr-1+ cells by polymeric nanoparticles for antigen cross-presentation

    PubMed Central

    Yang, Ya-Wun; Luo, Wen-Hui

    2017-01-01

    The objective of this study was to investigate the function of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) on the activation of antigen-specific CD8+ T cell responses via the CD11b+Gr−1+ myeloid subpopulations in murine bone marrow (BM). PLGA NPs containing ovalbumin (OVA) were fabricated by the double-emulsion method. The CD11b+Gr-1lowLy-6Chigh and CD11b+Gr-1highLy-6Clow subsets from mice bone marrow were sorted and treated with the PLGA/OVA NPs, followed by co-culture with the carboxyfluorescein succinimidyl ester (CFSE)-labelled OT-I CD8+ cells. Co-culture of OT-I CD8+ T cells with PLGA/OVA NPs-primed CD11b+Gr-1+ subsets upregulated the expression of IL-2, TNF-α, INF-γ, granzyme B, and perforin, resulting in proliferation of CD8+ T cells and differentiation into effector cytotoxic T lymphocytes (CTLs). In vivo proliferation of CFSE-labelled OT-I CD8+ cells in response to OVA was also obtained in the animals immunized with PLGA/OVA NPs. The results presented in this study demonstrate the ability of polymeric NPs to recruit two CD11b+Gr−1+ myeloid subsets for effective presentation of exogenous antigen to OT-I CD8+ T cells in the context of major histocompatibility complex (MHC) class I, leading to an induction of antigen-specific cell proliferation and differentiation into effector cells. PMID:28317931

  19. Recruitment of bone marrow CD11b+Gr-1+ cells by polymeric nanoparticles for antigen cross-presentation

    NASA Astrophysics Data System (ADS)

    Yang, Ya-Wun; Luo, Wen-Hui

    2017-03-01

    The objective of this study was to investigate the function of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) on the activation of antigen-specific CD8+ T cell responses via the CD11b+Gr-1+ myeloid subpopulations in murine bone marrow (BM). PLGA NPs containing ovalbumin (OVA) were fabricated by the double-emulsion method. The CD11b+Gr-1lowLy-6Chigh and CD11b+Gr-1highLy-6Clow subsets from mice bone marrow were sorted and treated with the PLGA/OVA NPs, followed by co-culture with the carboxyfluorescein succinimidyl ester (CFSE)-labelled OT-I CD8+ cells. Co-culture of OT-I CD8+ T cells with PLGA/OVA NPs-primed CD11b+Gr-1+ subsets upregulated the expression of IL-2, TNF-α, INF-γ, granzyme B, and perforin, resulting in proliferation of CD8+ T cells and differentiation into effector cytotoxic T lymphocytes (CTLs). In vivo proliferation of CFSE-labelled OT-I CD8+ cells in response to OVA was also obtained in the animals immunized with PLGA/OVA NPs. The results presented in this study demonstrate the ability of polymeric NPs to recruit two CD11b+Gr-1+ myeloid subsets for effective presentation of exogenous antigen to OT-I CD8+ T cells in the context of major histocompatibility complex (MHC) class I, leading to an induction of antigen-specific cell proliferation and differentiation into effector cells.

  20. Corruption of dendritic cell antigen presentation during acute GVHD leads to regulatory T-cell failure and chronic GVHD.

    PubMed

    Leveque-El Mouttie, Lucie; Koyama, Motoko; Le Texier, Laetitia; Markey, Kate A; Cheong, Melody; Kuns, Rachel D; Lineburg, Katie E; Teal, Bianca E; Alexander, Kylie A; Clouston, Andrew D; Blazar, Bruce R; Hill, Geoffrey R; MacDonald, Kelli P A

    2016-08-11

    Chronic graft-versus-host disease (cGVHD) is a major cause of late mortality following allogeneic bone marrow transplantation (BMT) and is characterized by tissue fibrosis manifesting as scleroderma and bronchiolitis obliterans. The development of acute GVHD (aGVHD) is a powerful clinical predictor of subsequent cGVHD, suggesting that aGVHD may invoke the immunologic pathways responsible for cGVHD. In preclinical models in which sclerodermatous cGVHD develops after a preceding period of mild aGVHD, we show that antigen presentation within major histocompatibility complex (MHC) class II of donor dendritic cells (DCs) is markedly impaired early after BMT. This is associated with a failure of regulatory T-cell (Treg) homeostasis and cGVHD. Donor DC-restricted deletion of MHC class II phenocopied this Treg deficiency and cGVHD. Moreover, specific depletion of donor Tregs after BMT also induced cGVHD, whereas adoptive transfer of Tregs ameliorated it. These data demonstrate that the defect in Treg homeostasis seen in cGVHD is a causative lesion and is downstream of defective antigen presentation within MHC class II that is induced by aGVHD.

  1. Membrane-bound heat shock proteins facilitate the uptake of dying cells and cross-presentation of cellular antigen.

    PubMed

    Zhu, Haiyan; Fang, Xiaoyun; Zhang, Dongmei; Wu, Weicheng; Shao, Miaomiao; Wang, Lan; Gu, Jianxin

    2016-01-01

    Heat shock proteins (HSPs) were originally identified as stress-responsive proteins and serve as molecular chaperones in different intracellular compartments. Translocation of HSPs to the cell surface and release of HSPs into the extracellular space have been observed during the apoptotic process and in response to a variety of cellular stress. Here, we report that UV irradiation and cisplatin treatment rapidly induce the expression of membrane-bound Hsp60, Hsp70, and Hsp90 upstream the phosphatidylserine exposure. Membrane-bound Hsp60, Hsp70 and Hsp90 could promote the release of IL-6 and IL-1β as well as DC maturation by the evaluation of CD80 and CD86 expression. On the other hand, Hsp60, Hsp70 and Hsp90 on cells could facilitate the uptake of dying cells by bone marrow-derived dendritic cells. Lectin-like oxidized LDL receptor-1 (LOX-1), as a common receptor for Hsp60, Hsp70, and Hsp90, is response for their recognition and mediates the uptake of dying cells. Furthermore, membrane-bound Hsp60, Hsp70 and Hsp90 could promote the cross-presentation of OVA antigen from E.G7 cells and inhibition of the uptake of dying cells by LOX-1 decreases the cross-presentation of cellular antigen. Therefore, the rapid exposure of HSPs on dying cells at the early stage allows for the recognition by and confers an activation signal to the immune system.

  2. Synthesis of Dideoxymycobactin Antigens Presented by CD1a Reveals T Cell Fine Specificity for Natural Lipopeptide Structures*

    PubMed Central

    Young, David C.; Kasmar, Anne; Moraski, Garrett; Cheng, Tan-Yun; Walz, Andrew J.; Hu, Jingdan; Xu, Yanping; Endres, Gregory W.; Uzieblo, Adam; Zajonc, Dirk; Costello, Catherine E.; Miller, Marvin J.; Moody, D. Branch

    2009-01-01

    Mycobacterium tuberculosis survival in cells requires mycobactin siderophores. Recently, the search for lipid antigens presented by the CD1a antigen-presenting protein led to the discovery of a mycobactin-like compound, dideoxymycobactin (DDM). Here we synthesize DDMs using solution phase and solid phase peptide synthesis chemistry. Comparison of synthetic standards to natural mycobacterial mycobactins by nuclear magnetic resonance and mass spectrometry allowed identification of an unexpected α-methyl serine unit in natural DDM. This finding further distinguishes these pre-siderophores as foreign compounds distinct from conventional peptides, and we provide evidence that this chemical variation influences the T cell response. One synthetic DDM recapitulated natural structures and potently stimulated T cells, making it suitable for patient studies of CD1a in infectious disease. DDM analogs differing in the stereochemistry of their butyrate or oxazoline moieties were not recognized by human T cells. Therefore, we conclude that T cells show precise specificity for both arms of the peptide, which are predicted to lie at the CD1a-T cell receptor interface. PMID:19605355

  3. KIM-1-/TIM-1-mediated phagocytosis links ATG5-/ULK1-dependent clearance of apoptotic cells to antigen presentation

    PubMed Central

    Brooks, Craig R; Yeung, Melissa Y; Brooks, Yang S; Chen, Hui; Ichimura, Takaharu; Henderson, Joel M; Bonventre, Joseph V

    2015-01-01

    Phagocytosis of apoptotic cells by both professional and semi-professional phagocytes is required for resolution of organ damage and maintenance of immune tolerance. KIM-1/TIM-1 is a phosphatidylserine receptor that is expressed on epithelial cells and can transform the cells into phagocytes. Here, we demonstrate that KIM-1 phosphorylation and association with p85 results in encapsulation of phagosomes by lipidated LC3 in multi-membrane organelles. KIM-1-mediated phagocytosis is not associated with increased ROS production, and NOX inhibition does not block LC3 lipidation. Autophagy gene expression is required for efficient clearance of apoptotic cells and phagosome maturation. KIM-1-mediated phagocytosis leads to pro-tolerogenic antigen presentation, which suppresses CD4 T-cell proliferation and increases the percentage of regulatory T cells in an autophagy gene-dependent manner. Taken together, these data reveal a novel mechanism of epithelial biology linking phagocytosis, autophagy and antigen presentation to regulation of the inflammatory response. PMID:26282792

  4. Saposins modulate human invariant Natural Killer T cells self-reactivity and facilitate lipid exchange with CD1d molecules during antigen presentation

    PubMed Central

    Salio, Mariolina; Ghadbane, Hemza; Dushek, Omer; Shepherd, Dawn; Cypen, Jeremy; Gileadi, Uzi; Aichinger, Michael C.; Napolitani, Giorgio; Qi, Xiaoyang; van der Merwe, P. Anton; Wojno, Justyna; Veerapen, Natacha; Cox, Liam R.; Besra, Gurdyal S.; Yuan, Weiming; Cresswell, Peter; Cerundolo, Vincenzo

    2013-01-01

    Lipid transfer proteins, such as molecules of the saposin family, facilitate extraction of lipids from biological membranes for their loading onto CD1d molecules. Although it has been shown that prosaposin-deficient mice fail to positively select invariant natural killer T (iNKT) cells, it remains unclear whether saposins can facilitate loading of endogenous iNKT cell agonists in the periphery during inflammatory responses. In addition, it is unclear whether saposins, in addition to loading, also promote dissociation of lipids bound to CD1d molecules. To address these questions, we used a combination of cellular assays and demonstrated that saposins influence CD1d-restricted presentation to human iNKT cells not only of exogenous lipids but also of endogenous ligands, such as the self-glycosphingolipid β-glucopyranosylceramide, up-regulated by antigen-presenting cells following bacterial infection. Furthermore, we demonstrated that in human myeloid cells CD1d-loading of endogenous lipids after bacterial infection, but not at steady state, requires trafficking of CD1d molecules through an endo-lysosomal compartment. Finally, using BIAcore assays we demonstrated that lipid-loaded saposin B increases the off-rate of lipids bound to CD1d molecules, providing important insights into the mechanisms by which it acts as a “lipid editor,” capable of fine-tuning loading and unloading of CD1d molecules. These results have important implications in understanding how to optimize lipid-loading onto antigen-presenting cells, to better harness iNKT cells central role at the interface between innate and adaptive immunity. PMID:24248359

  5. The immunogenicity of L1210 lymphoma clones correlates with their ability to function as antigen-presenting cells.

    PubMed

    Cycon, Kelly A; Clements, James L; Holtz, Renae; Fuji, Hiroshi; Murphy, Shawn P

    2009-09-01

    Major histocompatibility complex class II (MHCII) antigen expression is directly correlated with immunogenicity, and inversely correlated with tumorigenicity, in clones of the L1210 murine B lymphoma. Moreover, loss of MHCII expression on human diffuse large B-cell lymphoma is associated with dramatic decreases in patient survival. Thus, the role that MHCII antigens play in the progression of B-cell lymphomas is clinically important. In this study, we investigated the basis for the immunogenicity of MHCII(+) L1210 clones. Immunogenic, but not tumorigenic L1210 clones stimulated the proliferation of naïve T cells and their interleukin (IL)-2 production, which indicates that the immunogenic clones can function as antigen-presenting cells (APCs). However, subclonal variants of the immunogenic L1210 clones, which form tumours slowly in mice, could not activate T cells. The costimulatory molecules B7-1, B7-2 and CD40 were expressed on the immunogenic L1210 clones, but not the tumorigenic clones. Importantly, the tumour-forming subclonal variants expressed MHCII and B7-1, but lacked B7-2 and CD40. These results suggest that MHCII and B7-1 expression on L1210 cells is insufficient to activate naïve T cells, and, furthermore, loss of B7-2 and/or CD40 expression contributes to the decreased immunogenicity of L1210 subclones. Blocking B7-1 or B7-2 function on immunogenic L1210 cells reduced their capacity to activate naïve T cells. Furthermore, incubation of immunogenic L1210 cells with CD40 antibodies significantly enhanced APC function. Therefore, the immunogenicity of L1210 cells directly correlates (i) with their ability to stimulate naïve T cells, and (ii) with the concomitant expression of MHCII, B7-1, B7-2, and CD40.

  6. The immunodominant Eimeria acervulina sporozoite antigen previously described as p160/p240 is a 19-kilodalton antigen present in several Eimeria species.

    PubMed

    Laurent, F; Bourdieu, C; Kazanji, M; Yvoré, P; Péry, P

    1994-01-01

    A lambda Zap II cDNA expression library, constructed from Eimeria acervulina (PAPa46 strain) sporulated oocyst stage, was screened with sera raised to E. acervulina or Eimeria tenella oocysts in order to isolate clones coding for antigens common to the two species. Most of the clones isolated were derived from the same gene. Antisera raised to a recombinant glutathione-S-transferase fusion protein 1P reacted with an antigen of 19 kDa in immunoblot of E. acervulina sporulated and unsporulated oocysts. Immunofluorescence of E. acervulina sporozoites indicated that the antigen is located in the cytoplasm. The anti-1P antisera reacted on immunoblots of E. tenella with a 19-kDa antigen and by immunofluorescence on E. tenella, Eimeria maxima and Eimeria falciformis sporozoites, indicating that the antigen is conserved in Eimeria species. DNA sequencing indicated that the sequence was almost identical to that of clone cSZ1 previously described by Jenkins et al. using E. acervulina strain #12. The 1P insert hybridized to a 1150-nt mRNA from E. acervulina PAPa46 strain and strain #12, a size consistent with the observed molecular weight of the protein.

  7. IgE-Mediated Enhancement of CD4+ T Cell Responses in Mice Requires Antigen Presentation by CD11c+ Cells and Not by B Cells

    PubMed Central

    Henningsson, Frida; Ding, Zhoujie; Dahlin, Joakim S.; Linkevicius, Marius; Carlsson, Fredrik; Grönvik, Kjell-Olov; Hallgren, Jenny; Heyman, Birgitta

    2011-01-01

    IgE antibodies, administered to mice together with their specific antigen, enhance antibody and CD4+ T cell responses to this antigen. The effect is dependent on the low affinity receptor for IgE, CD23, and the receptor must be expressed on B cells. In vitro, IgE-antigen complexes are endocytosed via CD23 on B cells, which subsequently present the antigen to CD4+ T cells. This mechanism has been suggested to explain also IgE-mediated enhancement of immune responses in vivo. We recently found that CD23+ B cells capture IgE-antigen complexes in peripheral blood and rapidly transport them to B cell follicles in the spleen. This provides an alternative explanation for the requirement for CD23+ B cells. The aim of the present study was to determine whether B-cell mediated antigen presentation of IgE-antigen complexes explains the enhancing effect of IgE on immune responses in vivo. The ability of spleen cells, taken from mice 1–4 h after immunization with IgE-antigen, to present antigen to specific CD4+ T cells was analyzed. Antigen presentation was intact when spleens were depleted of CD19+ cells (i.e., primarily B cells) but was severely impaired after depletion of CD11c+ cells (i.e., primarily dendritic cells). In agreement with this, the ability of IgE to enhance proliferation of CD4+ T cells was abolished in CD11c-DTR mice conditionally depleted of CD11c+ cells. Finally, the lack of IgE-mediated enhancemen of CD4+ T cell responses in CD23-/- mice could be rescued by transfer of MHC-II-compatible as well as by MHC-II-incompatible CD23+ B cells. These findings argue against the idea that IgE-mediated enhancement of specific CD4+ T cell responses in vivo is caused by increased antigen presentation by B cells. A model where CD23+ B cells act as antigen transporting cells, delivering antigen to CD11c+ cells for presentation to T cells is consistent with available experimental data. PMID:21765910

  8. HIV Protease Inhibitor-Induced Cathepsin Modulation Alters Antigen Processing and Cross-Presentation.

    PubMed

    Kourjian, Georgio; Rucevic, Marijana; Berberich, Matthew J; Dinter, Jens; Wambua, Daniel; Boucau, Julie; Le Gall, Sylvie

    2016-05-01

    Immune recognition by T cells relies on the presentation of pathogen-derived peptides by infected cells, but the persistence of chronic infections calls for new approaches to modulate immune recognition. Ag cross-presentation, the process by which pathogen Ags are internalized, degraded, and presented by MHC class I, is crucial to prime CD8 T cell responses. The original degradation of Ags is performed by pH-dependent endolysosomal cathepsins. In this article, we show that HIV protease inhibitors (PIs) prescribed to HIV-infected persons variably modulate cathepsin activities in human APCs, dendritic cells and macrophages, and CD4 T cells, three cell subsets infected by HIV. Two HIV PIs acted in two complementary ways on cathepsin hydrolytic activities: directly on cathepsins and indirectly on their regulators by inhibiting Akt kinase activities, reducing NADPH oxidase 2 activation, and lowering phagolysosomal reactive oxygen species production and pH, which led to enhanced cathepsin activities. HIV PIs modified endolysosomal degradation and epitope production of proteins from HIV and other pathogens in a sequence-dependent manner. They altered cross-presentation of Ags by dendritic cells to epitope-specific T cells and T cell-mediated killing. HIV PI-induced modulation of Ag processing partly changed the MHC self-peptidome displayed by primary human cells. This first identification, to our knowledge, of prescription drugs modifying the regulation of cathepsin activities and the MHC-peptidome may provide an alternate therapeutic approach to modulate immune recognition in immune disease beyond HIV.

  9. A comparison of Ki-67 antigen presentation in acute generalized exanthematous pustulosis and pustular psoriasis.

    PubMed

    Chang, Shyue-Luen; Hu, Sindy; Hung, Shuen-Iu; Huang, Yau-Li; Hsiao, Wen-chin; Chung, Wen-Hung

    2010-09-01

    Ki-67 is an established marker of cell proliferation. It is highly expressed in psoriasis and correlated with the clinical severity of psoriasis. Higher number of Ki-67 positive keratinocytes has been observed in pustular psoriasis (PP) as compared with psoriasis vulgaris. As for Acute generalized exanthematous pustulosis (AGEP), a distinct disease entity but similar in many aspects of clinicopathologic features to PP, Ki-67 immunostaining presentation has never been investigated before. This study aimed to compare Ki-67 immunostaining presentation between PP and AGEP. By immunohistochemical staining, we compared Ki-67 immunostaining presentation on skin lesions of five patients of AGEP and five age-matched patients of PP. Ki-67 positive keratinocytes were counted and mean values were determined to compare between PP and AGEP. An augmented presence of Ki-67 positive keratinocytes was found in both AGEP and PP and they distributed not only in basal cell layer but in middle or even upper part of epidermis. Statistical analysis using Mann-Whitney U test showed no difference of epidermal proliferation rate between the two groups (P = 0.222). The results showed there was no difference of Ki-67 immunostaining presentation between AGEP and PP. Besides, we found marked increase of Ki-67-positive proliferating keratinocytes in AGEP and suggested that epidermal hyperproliferation may also play an important role in the formation of AGEP. We also discussed the possible pathophysiology of AGEP, possible epidermal architecture changes in AGEP and PP, and found the similarity in pathophysiology of AGEP and PP.

  10. Dysregulated luminal bacterial antigen-specific T-cell responses and antigen-presenting cell function in HLA-B27 transgenic rats with chronic colitis

    PubMed Central

    Qian, Bi-Feng; Tonkonogy, Susan L; Hoentjen, Frank; Dieleman, Levinus A; Sartor, R Balfour

    2005-01-01

    HLA-B27/β2 microglobulin transgenic (TG) rats spontaneously develop T-cell-mediated colitis when colonized with normal commensal bacteria, but remain disease-free under germ-free conditions. We investigated regulation of in vitro T-cell responses to enteric bacterial components. Bacterial lysates prepared from the caecal contents of specific pathogen-free (SPF) rats stimulated interferon-γ (IFN-γ) production by TG but not non-TG mesenteric lymph node (MLN) cells. In contrast, essentially equivalent amounts of interleukin-10 (IL-10) were produced by TG and non-TG cells. However, when cells from MLNs of non-TG rats were cocultured with TG MLN cells, no suppression of IFN-γ production was noted. Both non-TG and TG antigen-presenting cells (APC) pulsed with caecal bacterial lysate were able to induce IFN-γ production by TG CD4+ cells, although non-TG APC were more efficient than TG APC. Interestingly, the addition of exogenous IL-10 inhibited non-TG APC but not TG APC stimulation of IFN-γ production by cocultured TG CD4+ lymphocytes. Conversely, in the presence of exogenous IFN-γ, production of IL-10 was significantly lower in the supernatants of TG compared to non-TG APC cultures. We conclude that commensal luminal bacterial components induce exaggerated in vitro IFN-γ responses in HLA-B27 TG T cells, which may in turn inhibit the production of regulatory molecules, such as IL-10. Alterations in the production of IFN-γ, and in responses to this cytokine, as well as possible resistance of TG cells to suppressive regulation could together contribute to the development of chronic colitis in TG rats. PMID:16108823

  11. Assessment of the present NASA optical metrology capabilities and recommendations for establishing an in-house NASA Optical Metrology Group

    NASA Technical Reports Server (NTRS)

    Parks, Robert E.

    1991-01-01

    An investigation into when it was first recognized that there was a deficiency in NASA optical metrology oversight capability, why this deficiency existed unnoticed for so long, and a proposal for correcting the problem is presented. It is explained why this optical metrology oversight is so critical to program success and at the same time, why it is difficult to establish due to the nature of the technology. The solution proposed is the establishment of an Optics Metrology Group within the NASA/MSFC Optics Branch with a line of authority from NASA S & MA.

  12. Mung bean (Vigna radiata (L.)) coat extract modulates macrophage functions to enhance antigen presentation: A proteomic study.

    PubMed

    Hashiguchi, Akiko; Hitachi, Keisuke; Zhu, Wei; Tian, Jingkui; Tsuchida, Kunihiro; Komatsu, Setsuko

    2017-05-24

    The immunomodulatory effect of mung bean is mainly attributed to antioxidant properties of flavonoids; however, the precise machinery for biological effect on animal cells remains uncertain. To understand the physiological change produced by mung bean consumption, proteomic and metabolomic techniques were used. In vitro assay confirmed the importance of synergistic interaction among multiple flavonoids by IL-6 expression. Proteomic analysis detected that the abundance of 190 proteins was changed in lipopolysaccharide-stimulated RAW264.7 cells by treatment with coat extract. Pathway mapping revealed that a range of proteins were regulated including an interferon-responsive antiviral enzyme (2'-5'-oligoadenylate synthetase), antigen processing factors (immunoglobulin heavy chain-binding protein and protein disulfide-isomerase), and proteins related to proteasomal degradation. Major histocompatibility complex pathway was activated. These results suggest that mung bean consumption enhances immune response toward a Th2-promoting polarization. This study highlighted the immunomodulation of RAW264.7 cells in response to treatment with mung bean seed coat extract, using gel-free proteomic technique. The mechanism of immunomodulation by mung bean has not been described until today except for a report which identified HMGB1 suppression as a pathway underlying the protective effect against sepsis. This study suggested that the mung bean is involved in the regulation of antigen processing and presentation, and thus shifts immune response from acute febrile illness to specific/systemic and long-lasting immunity to protect the host. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Seoul virus suppresses NF-κB-mediated inflammatory responses of antigen presenting cells from Norway rats

    PubMed Central

    Au, Rebecca Y.; Jedlicka, Anne E.; Li, Wei; Pekosz, Andrew; Klein, Sabra L.

    2010-01-01

    Hantavirus infection reduces antiviral defenses, increases regulatory responses, and causes persistent infection in rodent hosts. To address whether hantaviruses alter the maturation and functional activity of antigen presenting cells (APCs), rat bone marrow-derived dendritic cells (BMDCs) and macrophages (BMDMs) were generated and infected with Seoul virus (SEOV) or stimulated with TLR ligands. SEOV infected both DCs and macrophages, but copies of viral RNA, viral antigen, and infectious virus titers were higher in macrophages. The expression of MHCII and CD80, production of IL-6, IL-10, and TNF-α, and expression of Ifnβ were attenuated in SEOV-infected APCs. Stimulation of APCs with poly I:C prior to SEOV infection increased the expression of activation markers and production of inflammatory cytokines and suppressed SEOV replication. Infection of APCs with SEOV suppressed LPS-induced activation and innate immune responses. Hantaviruses reduce the innate immune response potential of APCs derived from a natural host, which may influence persistence of these zoonotic viruses in the environment. PMID:20170933

  14. Presentation of peptides from Bacillus anthracis protective antigen on Tobacco Mosaic Virus as an epitope targeted anthrax vaccine.

    PubMed

    McComb, Ryan C; Ho, Chi-Lee; Bradley, Kenneth A; Grill, Laurence K; Martchenko, Mikhail

    2015-11-27

    The current anthrax vaccine requires improvements for rapidly invoking longer-lasting neutralizing antibody responses with fewer doses from a well-defined formulation. Designing antigens that target neutralizing antibody epitopes of anthrax protective antigen, a component of anthrax toxin, may offer a solution for achieving a vaccine that can induce strong and long lasting antibody responses with fewer boosters. Here we report implementation of a strategy for developing epitope focused virus nanoparticle vaccines against anthrax by using immunogenic virus particles to present peptides derived from anthrax toxin previously identified in (1) neutralizing antibody epitope mapping studies, (2) toxin crystal structure analyses to identify functional regions, and (3) toxin mutational analyses. We successfully expressed two of three peptide epitopes from anthrax toxin that, in previous reports, bound antibodies that were partially neutralizing against toxin activity, discovered cross-reactivity between vaccine constructs and toxin specific antibodies raised in goats against native toxin and showed that antibodies induced by our vaccine constructs also cross-react with native toxin. While protection against intoxication in cellular and animal studies were not as effective as in previous studies, partial toxin neutralization was observed in animals, demonstrating the feasibility of using plant-virus nanoparticles as a platform for epitope defined anthrax vaccines. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. The Role of XCR1 and its Ligand XCL1 in Antigen Cross-Presentation by Murine and Human Dendritic Cells

    PubMed Central

    Kroczek, Richard A.; Henn, Volker

    2012-01-01

    Recently, the chemokine receptor XCR1 has been found to be exclusively expressed on a subset of dendritic cell (DC) known to be involved in antigen cross-presentation. This review aims to summarize the known biology of the XCR1 receptor and its chemokine ligand XCL1, both in the mouse and the human. Further, any involvement of this receptor–ligand pair in antigen uptake, cross-presentation, and induction of innate and adaptive cytotoxic immunity is explored. The concept of antigen delivery to DC via the XCR1 receptor is discussed as a vaccination strategy for selective induction of cytotoxic immunity against certain pathogens or tumors. PMID:22566900

  16. Antigen recognition. V. Requirement for histocompatibility between antigen-presenting cell and B cell in the response to a thymus- dependent antigen, and lack of allogeneic restriction between T and B cells

    PubMed Central

    1981-01-01

    The restrictions imposed by the major histocompatibility complex on T-B- antigen-presenting cell (APC) interactions were studied with an in vivo adoptive transfer system, using mutually tolerant T and B cells taken from one-way fetal liver chimeras. It was found that the B cells and adoptive recipient (which provides APC function) have to share determinants encoded by the left-hand end of the H-2 complex for cooperation, whereas there is apparently no such requirement for T-B cell syngeneicity. Suppression arising from allogeneic effects between the host and the transferred T or B cells was excluded by the use of tolerant as well as normal adoptive recipients; both were functionally equivalent. We conclude that under experimental conditions, unrestricted helper T cell function and concurrent APC-B cell genetic restriction can be demonstrated in vivo. PMID:7276826

  17. Ionizing radiation affects human MART-1 melanoma antigen processing and presentation by dendritic cells.

    PubMed

    Liao, Yu-Pei; Wang, Chun-Chieh; Butterfield, Lisa H; Economou, James S; Ribas, Antoni; Meng, Wilson S; Iwamoto, Keisuke S; McBride, William H

    2004-08-15

    Radiation is generally considered to be an immunosuppressive agent that acts by killing radiosensitive lymphocytes. In this study, we demonstrate the noncytotoxic effects of ionizing radiation on MHC class I Ag presentation by bone marrow-derived dendritic cells (DCs) that have divergent consequences depending upon whether peptides are endogenously processed and loaded onto MHC class I molecules or are added exogenously. The endogenous pathway was examined using C57BL/6 murine DCs transduced with adenovirus to express the human melanoma/melanocyte Ag recognized by T cells (AdVMART1). Prior irradiation abrogated the ability of AdVMART1-transduced DCs to induce MART-1-specific T cell responses following their injection into mice. The ability of these same DCs to generate protective immunity against B16 melanoma, which expresses murine MART-1, was also abrogated by radiation. Failure of AdVMART1-transduced DCs to generate antitumor immunity following irradiation was not due to cytotoxicity or to radiation-induced block in DC maturation or loss in expression of MHC class I or costimulatory molecules. Expression of some of these molecules was affected, but because irradiation actually enhanced the ability of DCs to generate lymphocyte responses to the peptide MART-1(27-35) that is immunodominant in the context of HLA-A2.1, they were unlikely to be critical. The increase in lymphocyte reactivity generated by irradiated DCs pulsed with MART-1(27-35) also protected mice against growth of B16-A2/K(b) tumors in HLA-A2.1/K(b) transgenic mice. Taken together, these results suggest that radiation modulates MHC class I-mediated antitumor immunity by functionally affecting DC Ag presentation pathways.

  18. B cell antigen presentation is sufficient to drive neuroinflammation in an animal model of multiple sclerosis.

    PubMed

    Parker Harp, Chelsea R; Archambault, Angela S; Sim, Julia; Ferris, Stephen T; Mikesell, Robert J; Koni, Pandelakis A; Shimoda, Michiko; Linington, Christopher; Russell, John H; Wu, Gregory F

    2015-06-01

    B cells are increasingly regarded as integral to the pathogenesis of multiple sclerosis, in part as a result of the success of B cell-depletion therapy. Multiple B cell-dependent mechanisms contributing to inflammatory demyelination of the CNS have been explored using experimental autoimmune encephalomyelitis (EAE), a CD4 T cell-dependent animal model for multiple sclerosis. Although B cell Ag presentation was suggested to regulate CNS inflammation during EAE, direct evidence that B cells can independently support Ag-specific autoimmune responses by CD4 T cells in EAE is lacking. Using a newly developed murine model of in vivo conditional expression of MHC class II, we reported previously that encephalitogenic CD4 T cells are incapable of inducing EAE when B cells are the sole APC. In this study, we find that B cells cooperate with dendritic cells to enhance EAE severity resulting from myelin oligodendrocyte glycoprotein (MOG) immunization. Further, increasing the precursor frequency of MOG-specific B cells, but not the addition of soluble MOG-specific Ab, is sufficient to drive EAE in mice expressing MHCII by B cells alone. These data support a model in which expansion of Ag-specific B cells during CNS autoimmunity amplifies cognate interactions between B and CD4 T cells and have the capacity to independently drive neuroinflammation at later stages of disease.

  19. Recognition of Salmonella by Dectin-1 induces presentation of peptide antigen to type B T cells

    PubMed Central

    Jackson, Nicola; Compton, Evan; Trowsdale, John; Kelly, Adrian P

    2014-01-01

    Type B T cells recognize peptide–MHC class II (pMHCII) isoforms that are structurally distinct from those recognized by conventional type A T cells. These alternative type B conformers result from peptide loading in the absence of HLA-DM. Type A conformers are more stable than type B pMHCII conformers but bind the same peptide in the same register. Here, we show that interaction of Salmonella Typhimurium with bone marrow derived dendritic cells (BMDCs) isolated from C3H/HeNCr1 mice results in enhanced presentation of peptide Ag to type B T cells. The effect could be mimicked by purified PAMPs, the most potent of which were curdlan and zymosan, β-(1,3)-glucan-containing polymers that are recognized by Dectin-1. Blocking of Dectin-1 with Ab and laminarin inhibited the induction of the type B T-cell response by BMDCs, confirming its role as a PRR for S. Typhimurium. Splenic DCs (sDCs) expressed Dectin-1 but were refractive to the induction of type B responses by S. Typhimurium and curdlan. Type B T cells have been shown to escape thymic tolerance and to transfer pathology in an autoimmune disease model. The induction of type B responses by gram-negative bacteria provides a mechanism by which autoreactive T cells may be produced during infection. PMID:24458430

  20. Asymmetric cell division of T cells upon antigen presentation uses multiple conserved mechanisms.

    PubMed

    Oliaro, Jane; Van Ham, Vanessa; Sacirbegovic, Faruk; Pasam, Anupama; Bomzon, Ze'ev; Pham, Kim; Ludford-Menting, Mandy J; Waterhouse, Nigel J; Bots, Michael; Hawkins, Edwin D; Watt, Sally V; Cluse, Leonie A; Clarke, Chris J P; Izon, David J; Chang, John T; Thompson, Natalie; Gu, Min; Johnstone, Ricky W; Smyth, Mark J; Humbert, Patrick O; Reiner, Steven L; Russell, Sarah M

    2010-07-01

    Asymmetric cell division is a potential means by which cell fate choices during an immune response are orchestrated. Defining the molecular mechanisms that underlie asymmetric division of T cells is paramount for determining the role of this process in the generation of effector and memory T cell subsets. In other cell types, asymmetric cell division is regulated by conserved polarity protein complexes that control the localization of cell fate determinants and spindle orientation during division. We have developed a tractable, in vitro model of naive CD8(+) T cells undergoing initial division while attached to dendritic cells during Ag presentation to investigate whether similar mechanisms might regulate asymmetric division of T cells. Using this system, we show that direct interactions with APCs provide the cue for polarization of T cells. Interestingly, the immunological synapse disseminates before division even though the T cells retain contact with the APC. The cue from the APC is translated into polarization of cell fate determinants via the polarity network of the Par3 and Scribble complexes, and orientation of the mitotic spindle during division is orchestrated by the partner of inscuteable/G protein complex. These findings suggest that T cells have selectively adapted a number of evolutionarily conserved mechanisms to generate diversity through asymmetric cell division.

  1. Identification of a prostate-specific membrane antigen-derived peptide capable of eliciting both cellular and humoral immune responses in HLA-A24+ prostate cancer patients.

    PubMed

    Kobayashi, Kazuhiko; Noguchi, Masanori; Itoh, Kyogo; Harada, Mamoru

    2003-07-01

    We tried to identify prostate-specific membrane antigen (PSMA)-derived peptides capable of eliciting both cellular and humoral immune responses in peripheral blood mononuclear cells (PBMCs) and plasma of HLA-A24(+) prostate cancer patients, respectively. For cellular response, peptide-specific and prostate cancer-reactive responses of in vitro-stimulated PBMCs were examined with regard to interferon (IFN)-gamma production and cytotoxicity against both a parental HLA-A24(-) prostate cancer cell line (PC-93) and an HLA-A24-expressing transfectant cell line (PC93-A24). For humoral response, patients' plasma was tested for reactivity to the peptides by means of an enzyme-linked immunosorbent assay (ELISA). Among 13 PSMA peptides, PSMA 624-632 peptide induced peptide-specific and tumor-reactive cytotoxic T lymphocytes (CTLs) most effectively. The PSMA 624-632 peptide-stimulated PBMCs from either healthy donors or