The antigen presenting cells instruct plasma cell differentiation.

Science.gov (United States)

Xu, Wei; Banchereau, Jacques

2014-01-06

The professional antigen presenting cells (APCs), including many subsets of dendritic cells and macrophages, not only mediate prompt but non-specific response against microbes, but also bridge the antigen-specific adaptive immune response through antigen presentation. In the latter, typically activated B cells acquire cognate signals from T helper cells in the germinal center of lymphoid follicles to differentiate into plasma cells (PCs), which generate protective antibodies. Recent advances have revealed that many APC subsets provide not only "signal 1" (the antigen), but also "signal 2" to directly instruct the differentiation process of PCs in a T-cell-independent manner. Herein, the different signals provided by these APC subsets to direct B cell proliferation, survival, class switching, and terminal differentiation are discussed. We furthermore propose that the next generation of vaccines for boosting antibody response could be designed by targeting APCs.

Can resting B cells present antigen to T cells

International Nuclear Information System (INIS)

Ashwell, J.D.; DeFranco, A.L.; Paul, W.E.; Schwartz, R.H.

1985-01-01

Antigen stimulation of T lymphocytes can occur only in the presence of an antigen-presenting cell (APC). An ever-increasing number of cell types have been found to act as APCs; these include macrophages, splenic and lymph node dendritic cells, and Langerhans cells of the skin. Although activated B lymphocytes and B cell lymphomas are known to serve as APCs, it has been generally believed that resting B cells cannot perform this function. However, in recent studies the authors have found that resting B cells can indeed present soluble antigen to T cell clones as well as to antigen-primed T cells. The previous difficulty in demonstrating this activity can be explained by the finding that, in contrast to macrophages and dendritic cells, the antigen-presenting ability of resting B cells is very radiosensitive. Macrophages are usually irradiated with 2000-3300 rads to prevent them from incorporating [ 3 H]thymidine in the T cell proliferation assay. Resting B cells, however, begin to lose presenting function at 1500 rads and have completely lost this activity at 3300 rads. It was also possible to distinguish two distinct T cell clonal phenotypes when resting B cells were used as APCs on the basis of two different assays (T cell proliferation, and B cell proliferation resulting from T cell activation). The majority of T cell clones tested were capable of both proliferating themselves and inducing the proliferation of B cells. Some T cells clones, however, could not proliferate in the presence of antigen and B cell APCs, although they were very good at inducing the proliferation of B cells

Antigen specific T-cell responses against tumor antigens are controlled by regulatory T cells in patients with prostate cancer.

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Hadaschik, Boris; Su, Yun; Huter, Eva; Ge, Yingzi; Hohenfellner, Markus; Beckhove, Philipp

2012-04-01

Immunotherapy is a promising approach in an effort to control castration resistant prostate cancer. We characterized tumor antigen reactive T cells in patients with prostate cancer and analyzed the suppression of antitumor responses by regulatory T cells. Peripheral blood samples were collected from 57 patients with histologically confirmed prostate cancer, 8 patients with benign prostatic hyperplasia and 16 healthy donors. Peripheral blood mononuclear cells were isolated and antigen specific interferon-γ secretion of isolated T cells was analyzed by enzyme-linked immunospot assay. T cells were functionally characterized and T-cell responses before and after regulatory T-cell depletion were compared. As test tumor antigens, a panel of 11 long synthetic peptides derived from a total of 8 tumor antigens was used, including prostate specific antigen and prostatic acid phosphatase. In patients with prostate cancer we noted a 74.5% effector T-cell response rate compared with only 25% in patients with benign prostatic hyperplasia and 31% in healthy donors. In most patients 2 or 3 tumor antigens were recognized. Comparing various disease stages there was a clear increase in the immune response against prostate specific antigens from intermediate to high risk tumors and castration resistant disease. Regulatory T-cell depletion led to a significant boost in effector T-cell responses against prostate specific antigen and prostatic acid phosphatase. Tumor specific effector T cells were detected in most patients with prostate cancer, especially those with castration resistant prostate cancer. Since effector T-cell responses against prostate specific antigens strongly increased after regulatory T-cell depletion, our results indicate that immunotherapy efficacy could be enhanced by decreasing regulatory T cells. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Facts on the fragmentation of antigens in presenting cells, on the association of antigen fragments with MHC molecules in cell-free systems, and speculation on the cell biology of antigen processing

DEFF Research Database (Denmark)

Werdelin, O; Mouritsen, S; Petersen, B L

1988-01-01

The processing of a protein antigen is a multi-step event taking place in antigen-presenting cells. Processing is a prerequisite for the recognition of most antigens by T lymphocytes. The antigen is ingested by endocytosis, transported to an acid cellular compartment and subjected to proteolytic...... fragmentation. Some of the antigen fragments bind to MHC class II molecules and are transported to the surface of the antigen-presenting cell where the actual presentation to T lymphocytes occurs. The nature of the processed antigen, how and where it is derived and subsequently becomes associated with MHC...... molecules are the questions discussed in this review. To us, the entire concept of processing has appeal not only because it explains some hitherto well-established, but poorly understood, phenomena such as the fact that T lymphocytes focus their attention entirely upon antigens on other cells. It has...

Antigen presentation by resting B cells. Radiosensitivity of the antigen-presentation function and two distinct pathways of T cell activation

International Nuclear Information System (INIS)

Ashwell, J.D.; DeFranco, A.L.; Paul, W.E.; Schwartz, R.H.

1984-01-01

In this report we have examined the ability of small resting B cells to act as antigen-presenting cells (APC) to antigen-specific MHC-restricted T cells as assessed by either T cell proliferation or T cell-dependent B cell stimulation. We found that 10 of 14 in vitro antigen-specific MHC-restricted T cell clones and lines and three of four T cell hybridomas could be induced to either proliferate or secrete IL-2 in the presence of lightly irradiated (1,000 rads) purified B cells and the appropriate foreign antigen. All T cell lines and hybridomas were stimulated to proliferate or make IL-2 by macrophage- and dendritic cell-enriched populations and all T cells tested except one hybridoma caused B cell activation when stimulated with B cells as APC. Furthermore, lightly irradiated, highly purified syngeneic B cells were as potent a source of APC for inducing B cell activation as were low density dendritic and macrophage-enriched cells. Lymph node T cells freshly taken from antigen-primed animals were also found to proliferate when cultured with purified B cells and the appropriate antigen. This APC function was easily measured when the cells were irradiated with 1,000 rads, but was greatly diminished or absent when they were irradiated with 3,300 rads. In addition, this radiosensitivity allowed us to easily distinguish B cell antigen presentation from presentation by the dendritic cell and macrophage, as the latter was resistant to 3,300 rads. Finally, one T cell clone that failed to proliferate when B cells were used as APC was able to recruit allogeneic B cells to proliferate in the presence of syngeneic B cells and the appropriate antigen. This result suggests that there are at least two distinct pathways of activation in T cells, one that leads to T cell proliferation and one that leads to the secretion of B cell recruitment factor(s)

Characterization of Antigen-Specific B Cells Using Nominal Antigen-Coated Flow-Beads

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Akl, Ahmed; Lepetit, Maud; Crochette, Romain; Giral, Magali; Lepourry, Julie; Pallier, Annaick; Castagnet, Stéphanie; Dugast, Emilie; Guillot-Gueguen, Cécile; Jacq-Foucher, Marylène; Saulquin, Xavier; Cesbron, Anne; Laplaud, David; Nicot, Arnaud; Brouard, Sophie; Soulillou, Jean-Paul

2013-01-01

In order to characterize the reactivity of B cells against nominal antigens, a method based on the coupling of antigens onto the surface of fluorescent core polystyrene beads was developed. We first demonstrate that murine B cells with a human MOG-specific BCR are able to interact with MOG-coated beads and do not recognize beads coated with human albumin or pp65. B cells purified from human healthy volunteer blood or immunized individuals were tested for their ability to interact with various nominal antigens, including viral, vaccine, self and alloantigens, chosen for their usefulness in studying a variety of pathological processes. A substantial amount of B cells binding self-antigen MOG-coated beads can be detected in normal blood. Furthermore, greater frequencies of B cell against anti-Tetanic Toxin or anti-EBNA1 were observed in primed individuals. This method can reveal increased frequencies of anti-HLA committed B cells in patients with circulating anti-HLA antibodies compared to unsensitized patients and normal individuals. Of interest, those specific CD19 cells were preferentially identified within CD27−IgD+ (i-e naïve) subset. These observations suggest that a broad range of medical situations could benefit from a tool that allows the detection, the quantification and the characterization of antigen-specific blood B cells. PMID:24386360

Presentation of lipid antigens to T cells.

Science.gov (United States)

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.

Characterization of antigen association with accessory cells: specific removal of processed antigens from the cell surface by phospholipases

International Nuclear Information System (INIS)

Falo, L.D. Jr.; Haber, S.I.; Herrmann, S.; Benacerraf, B.; Rock, K.L.

1987-01-01

To characterize the basis for the cell surface association of processed antigen with the antigen-presenting cell (APC) the authors analyzed its sensitivity to enzymatic digestion. Antigen-exposed APC that are treated with phospholipase and then immediately fixed lose their ability to stimulate antigen-plus-Ia-specific T-T hybridomas. This effect is seen with highly purified phospholipase A 2 and phospholipase C. In addition it is observed with three distinct antigens - ovalbumin, bovine insulin, and poly(LGlu 56 LLys 35 LPhe 9 )[(GluLysPhe)/sub n/]. The effect of phospholipases is highly specific. Identically treated APC are equivalent to control in their ability to stimulate alloreactive hybridomas specific for precisely the same Ia molecule that is corecognized by antigen-plus-Ia-specific hybrids. Furthermore, the antigen-presenting function of enzyme-treated, fixed APC can be reconstituted by the addition of exogenous in vitro processed or processing independent antigens. In parallel studies 125 I-labeled avidin was shown to specifically bind to APC that were previously exposed and allowed to process biotin-insulin. Biotin-insulin-exposed APC that are pretreated with phospholipase bind significantly less 125 I-labeled avidin than do untreated, exposed APC. Identical enzyme treatment does not reduce the binding of avidin to a biotinylated antibody already bound to class II major histocompatibility complex molecules of APC. These studies demonstrate that phospholipase effectively removes processed cell surface antigen

Antigen-specific T cell activation independently of the MHC: chimeric antigen receptor (CAR-redirected T cells.

Directory of Open Access Journals (Sweden)

Hinrich eAbken

2013-11-01

Full Text Available Adoptive T cell therapy has recently shown powerful in initiating a lasting anti-tumor response with spectacular therapeutic success in some cases. Specific T cell therapy, however, is limited since a number of cancer cells are not recognized by T cells due to various mechanisms including the limited availability of tumor-specific T cells and deficiencies in antigen processing or major histocompatibility complex (MHC expression of cancer cells. To make adoptive cell therapy applicable for the broad variety of cancer entities, patient's T cells are engineered ex vivo with pre-defined specificity by a recombinant chimeric antigen receptor (CAR which consists in the extracellular part of an antibody-derived domain for binding with a tumor-associated antigen and in the intracellular part of a TCR-derived signaling moiety for T cell activation. The specificity of CAR mediated T cell recognition is defined by the antibody domain, is independent of MHC presentation and can be extended to any target for which an antibody is available. We discuss the advantages and limitations of MHC-independent T cell targeting by an engineered CAR and review most significant progress recently made in early stage clinical trials to treat cancer.

Harnessing Dendritic Cells for Tumor Antigen Presentation

Energy Technology Data Exchange (ETDEWEB)

Nierkens, Stefan [Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Geert Grooteplein 28, Nijmegen 6525 GA (Netherlands); Janssen, Edith M., E-mail: edith.janssen@cchmc.org [Division of Molecular Immunology, Cincinnati Children' s Hospital Research Foundation, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH 45229 (United States)

2011-04-26

Dendritic cells (DC) are professional antigen presenting cells that are crucial for the induction of anti-tumor T cell responses. As a consequence, research has focused on the harnessing of DCs for therapeutic interventions. Although current strategies employing ex vivo-generated and tumor-antigen loaded DCs have been proven feasible, there are still many obstacles to overcome in order to improve clinical trial successes and offset the cost and complexity of customized cell therapy. This review focuses on one of these obstacles and a pivotal step for the priming of tumor-specific CD8{sup +} and CD4{sup +} T cells; the in vitro loading of DCs with tumor antigens.

Nucleolin down-regulation is involved in ADP-induced cell cycle arrest in S phase and cell apoptosis in vascular endothelial cells.

Directory of Open Access Journals (Sweden)

Wenmeng Wang

Full Text Available High concentration of extracellular ADP has been reported to induce cell apoptosis, but the molecular mechanisms remain not fully elucidated. In this study, we found by serendipity that ADP treatment of human umbilical vein endothelial cells (HUVEC and human aortic endothelial cells (HAEC down-regulated the protein level of nucleolin in a dose- and time-dependent manner. ADP treatment did not decrease the transcript level of nucloelin, suggesting that ADP might induce nucleolin protein degradation. HUVEC and HAEC expressed ADP receptor P2Y13 receptor, but did not express P2Y1 or P2Y12 receptors. However, P2Y1, 12, 13 receptor antagonists MRS2179, PSB0739, MRS2211 did not inhibit ADP-induced down-regulation of nucleolin. Moreover, MRS2211 itself down-regulated nucleolin protein level. In addition, 2-MeSADP, an agonist for P2Y1, 12 and 13 receptors, did not down-regulate nucleolin protein. These results suggested that ADP-induced nucleolin down-regulation was not due to the activation of P2Y1, 12, or 13 receptors. We also found that ADP treatment induced cell cycle arrest in S phase, cell apoptosis and cell proliferation inhibition via nucleolin down-regulation. The over-expression of nucleolin by gene transfer partly reversed ADP-induced cell cycle arrest, cell apoptosis and cell proliferation inhibition. Furthermore, ADP sensitized HUVEC to cisplatin-induced cell death by the down-regulation of Bcl-2 expression. Taken together, we found, for the first time to our knowledge, a novel mechanism by which ADP regulates cell proliferation by induction of cell cycle arrest and cell apoptosis via targeting nucelolin.

Transgenic Expression of IL15 Improves Antiglioma Activity of IL13Rα2-CAR T Cells but Results in Antigen Loss Variants.

Science.gov (United States)

Krenciute, Giedre; Prinzing, Brooke L; Yi, Zhongzhen; Wu, Meng-Fen; Liu, Hao; Dotti, Gianpietro; Balyasnikova, Irina V; Gottschalk, Stephen

2017-07-01

Glioblastoma (GBM) is the most aggressive primary brain tumor in adults and is virtually incurable with conventional therapies. Immunotherapy with T cells expressing GBM-specific chimeric antigen receptors (CAR) is an attractive approach to improve outcomes. Although CAR T cells targeting GBM antigens, such as IL13 receptor subunit α2 (IL13Rα2), HER2, and EGFR variant III (EGFRvIII), have had antitumor activity in preclinical models, early-phase clinical testing has demonstrated limited antiglioma activity. Transgenic expression of IL15 is an appealing strategy to enhance CAR T-cell effector function. We tested this approach in our IL13Rα2-positive glioma model in which limited IL13Rα2-CAR T-cell persistence results in recurrence of antigen-positive gliomas. T cells were genetically modified with retroviral vectors encoding IL13Rα2-CARs or IL15 (IL13Rα2-CAR.IL15 T cells). IL13Rα2-CAR.IL15 T cells recognized glioma cells in an antigen-dependent fashion, had greater proliferative capacity, and produced more cytokines after repeated stimulations in comparison with IL13Rα2-CAR T cells. No autonomous IL13Rα2-CAR.IL15 T-cell proliferation was observed; however, IL15 expression increased IL13Rα2-CAR T-cell viability in the absence of exogenous cytokines or antigen. In vivo , IL13Rα2-CAR.IL15 T cells persisted longer and had greater antiglioma activity than IL13Rα2-CAR T cells, resulting in a survival advantage. Gliomas recurring after 40 days after T-cell injection had downregulated IL13Rα2 expression, indicating that antigen loss variants occur in the setting of improved T-cell persistence. Thus, CAR T cells for GBM should not only be genetically modified to improve their proliferation and persistence, but also to target multiple antigens. Summary: Glioblastoma responds imperfectly to immunotherapy. Transgenic expression of IL15 in T cells expressing CARs improved their proliferative capacity, persistence, and cytokine production. The emergence of antigen

Cell-permeable nanobodies for targeted immunolabelling and antigen manipulation in living cells.

Science.gov (United States)

Herce, Henry D; Schumacher, Dominik; Schneider, Anselm F L; Ludwig, Anne K; Mann, Florian A; Fillies, Marion; Kasper, Marc-André; Reinke, Stefan; Krause, Eberhard; Leonhardt, Heinrich; Cardoso, M Cristina; Hackenberger, Christian P R

2017-08-01

Functional antibody delivery in living cells would enable the labelling and manipulation of intracellular antigens, which constitutes a long-thought goal in cell biology and medicine. Here we present a modular strategy to create functional cell-permeable nanobodies capable of targeted labelling and manipulation of intracellular antigens in living cells. The cell-permeable nanobodies are formed by the site-specific attachment of intracellularly stable (or cleavable) cyclic arginine-rich cell-penetrating peptides to camelid-derived single-chain VHH antibody fragments. We used this strategy for the non-endocytic delivery of two recombinant nanobodies into living cells, which enabled the relocalization of the polymerase clamp PCNA (proliferating cell nuclear antigen) and tumour suppressor p53 to the nucleolus, and thereby allowed the detection of protein-protein interactions that involve these two proteins in living cells. Furthermore, cell-permeable nanobodies permitted the co-transport of therapeutically relevant proteins, such as Mecp2, into the cells. This technology constitutes a major step in the labelling, delivery and targeted manipulation of intracellular antigens. Ultimately, this approach opens the door towards immunostaining in living cells and the expansion of immunotherapies to intracellular antigen targets.

Cell-permeable nanobodies for targeted immunolabelling and antigen manipulation in living cells

Science.gov (United States)

Herce, Henry D.; Schumacher, Dominik; Schneider, Anselm F. L.; Ludwig, Anne K.; Mann, Florian A.; Fillies, Marion; Kasper, Marc-André; Reinke, Stefan; Krause, Eberhard; Leonhardt, Heinrich; Cardoso, M. Cristina; Hackenberger, Christian P. R.

2017-08-01

Functional antibody delivery in living cells would enable the labelling and manipulation of intracellular antigens, which constitutes a long-thought goal in cell biology and medicine. Here we present a modular strategy to create functional cell-permeable nanobodies capable of targeted labelling and manipulation of intracellular antigens in living cells. The cell-permeable nanobodies are formed by the site-specific attachment of intracellularly stable (or cleavable) cyclic arginine-rich cell-penetrating peptides to camelid-derived single-chain VHH antibody fragments. We used this strategy for the non-endocytic delivery of two recombinant nanobodies into living cells, which enabled the relocalization of the polymerase clamp PCNA (proliferating cell nuclear antigen) and tumour suppressor p53 to the nucleolus, and thereby allowed the detection of protein-protein interactions that involve these two proteins in living cells. Furthermore, cell-permeable nanobodies permitted the co-transport of therapeutically relevant proteins, such as Mecp2, into the cells. This technology constitutes a major step in the labelling, delivery and targeted manipulation of intracellular antigens. Ultimately, this approach opens the door towards immunostaining in living cells and the expansion of immunotherapies to intracellular antigen targets.

Comparison of antigen-specific T-cell responses of tuberculosis patients using complex or single antigens of Mycobacterium tuberculosis

DEFF Research Database (Denmark)

Mustafa, A S; Amoudy, H A; Wiker, H G

1998-01-01

GroES, rPstS, rGroEL and rDnaK) antigens of Mycobacterium tuberculosis. The responses of PBMC to these defined antigens were compared with the corresponding results obtained with complex antigens, such as whole-cell M. tuberculosis, M. tuberculosis culture filtrate (MT-CF) and cell wall antigens, as well...... as the vaccine strain, Mycobacterium bovis bacillus Calmette-Guerin (BCG). In addition, M. tuberculosis and MT-CF-induced T-cell lines were tested in the same assays against the panel of purified and complex antigens. The compiled data from PBMC and T-cell lines tested for antigen-induced proliferation and IFN...

Mature IgM-expressing plasma cells sense antigen and develop competence for cytokine production upon antigenic challenge

Science.gov (United States)

Blanc, Pascal; Moro-Sibilot, Ludovic; Barthly, Lucas; Jagot, Ferdinand; This, Sébastien; de Bernard, Simon; Buffat, Laurent; Dussurgey, Sébastien; Colisson, Renaud; Hobeika, Elias; Fest, Thierry; Taillardet, Morgan; Thaunat, Olivier; Sicard, Antoine; Mondière, Paul; Genestier, Laurent; Nutt, Stephen L.; Defrance, Thierry

2016-01-01

Dogma holds that plasma cells, as opposed to B cells, cannot bind antigen because they have switched from expression of membrane-bound immunoglobulins (Ig) that constitute the B-cell receptor (BCR) to production of the secreted form of immunoglobulins. Here we compare the phenotypical and functional attributes of plasma cells generated by the T-cell-dependent and T-cell-independent forms of the hapten NP. We show that the nature of the secreted Ig isotype, rather than the chemical structure of the immunizing antigen, defines two functionally distinct populations of plasma cells. Fully mature IgM-expressing plasma cells resident in the bone marrow retain expression of a functional BCR, whereas their IgG+ counterparts do not. Antigen boost modifies the gene expression profile of IgM+ plasma cells and initiates a cytokine production program, characterized by upregulation of CCL5 and IL-10. Our results demonstrate that IgM-expressing plasma cells can sense antigen and acquire competence for cytokine production upon antigenic challenge. PMID:27924814

Plastic downregulation of the transcriptional repressor BCL6 during maturation of human dendritic cells

International Nuclear Information System (INIS)

Pantano, Serafino; Jarrossay, David; Saccani, Simona; Bosisio, Daniela; Natoli, Gioacchino

2006-01-01

Dendritic cell (DC) maturation links peripheral events initiated by the encounter with pathogens to the activation and expansion of antigen-specific T lymphocytes in secondary lymphoid organs. Here, we describe an as yet unrecognized modulator of human DC maturation, the transcriptional repressor BCL6. We found that both myeloid and plasmacytoid DCs constitutively express BCL6, which is rapidly downregulated following maturation triggered by selected stimuli. Both in unstimulated and maturing DCs, control of BCL6 protein levels reflects the convergence of several mechanisms regulating BCL6 stability, mRNA transcription and nuclear export. By regulating the induction of several genes implicated in the immune response, including inflammatory cytokines, chemokines and survival genes, BCL6 may represent a pivotal modulator of the afferent branch of the immune response

Radioimmunoassay for tumor antigen of human cervical squamous cell carcinoma

International Nuclear Information System (INIS)

Kato, H.; Torigoe, T.

1977-01-01

A heterologous antiserum for human cervical squamous cell carcinoma was prepared and specificity determined by Ouchterlony immunodiffusion and immunofluorescence studies. With this antiserum, a tumor antigen was purified from human cervical squamous cell carcinoma tissue. The specificities of the antigen and the antiserum were then re-examined by a radioimmunoassay method using 125 I-labeled purified antigen. Although normal cervical tissue extract showed a moderate cross-reactivity in the radioimmunoassay, the circulating antigen activity could not be detected in normal women or in several patients with other carcinomas, whereas 27 of 35 patients with cervical squamous cell carcinoma showed detectable serum antigen activity. All patients with advanced stages of cervical squamous cell carcinoma showed detectable antigen levels. These results indicate that there is a quantitative abnormality, at least, of this tumor antigen in patients with cervical squamous cell carcinoma and that the radioimmunoassay for the antigen is a potentially useful tool in clinical care

Downregulation of HDAC9 inhibits cell proliferation and tumor formation by inducing cell cycle arrest in retinoblastoma

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yiting; Wu, Dan; Xia, Fengjie; Xian, Hongyu; Zhu, Xinyue [Medical School of Nanjing University, Department of Ophthalmology, Jinling Hospital, Nanjing, 210002 (China); Cui, Hongjuan, E-mail: hcui@swu.edu.cn [State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems Biology, Southwest University, Chongqing, 400716 (China); Huang, Zhenping, E-mail: huangzhenping19633@163.com [Medical School of Nanjing University, Department of Ophthalmology, Jinling Hospital, Nanjing, 210002 (China)

2016-04-29

Histone deacetylase 9 (HDAC9) is a member of class II HDACs, which regulates a wide variety of normal and abnormal physiological functions. Recently, HDAC9 has been found to be overexpressed in some types of human cancers. However, the role of HDAC9 in retinoblastoma remains unclear. In this study, we found that HDAC9 was commonly expressed in retinoblastoma tissues and HDAC9 was overexpressed in prognostically poor retinoblastoma patients. Through knocking down HDAC9 in Y79 and WERI-Rb-1 cells, the expression level of HDAC9 was found to be positively related to cell proliferation in vitro. Further investigation indicated that knockdown HDAC9 could significantly induce cell cycle arrest at G1 phase in retinoblastoma cells. Western blot assay showed downregulation of HDAC9 could significantly decrease cyclin E2 and CDK2 expression. Lastly, xenograft study in nude mice showed that downregulation of HDAC9 inhibited tumor growth and development in vivo. Therefore, our results suggest that HDAC9 could serve as a novel potential therapeutic target in the treatment of retinoblastoma. - Highlights: • High expression of HDAC9 correlates with poor patient prognosis. • Downregulation of HDAC9 inhibits cell proliferation in retinoblastoma cells. • Downregulation of HDAC9 induces cell cycle arrest at G1 phase in retinoblastoma cells. • Downregulation of HDAC9 suppresses tumor growth in nude mice.

Splenic B cells and antigen-specific B cells process anti-Ig in a similar manner

International Nuclear Information System (INIS)

Myers, C.D.; Vitetta, E.S.

1989-01-01

B lymphocytes can process and present antigen to T cells. However, the fate of native antigen after its binding to specific B cells, i.e., the intracellular events involved in the processing and recycling of the antigenic fragments to the cell surface for antigen presentation, are not well understood. In the present study, we demonstrate that murine B cells degrade anti-Ig molecules bound to their surface and release acid soluble fragments into the supernatant. We also demonstrate that the kinetics of this process are identical for anti-mu, anti-delta, and anti-light chain antibodies, indicating that both surface IgM and surface IgD are equally effective in binding antigen and directing its processing. We also describe the effects of azide, chloroquine, and irradiation on this process. To extend these studies to the processing of specifically bound antigen, we demonstrate that highly purified trinitrophenyl antigen-binding cells degrade anti-Ig molecules with the same kinetics as unpurified splenic B cells. Thus, this purified population provides a suitable model system for the analysis of antigen degradation by antigen-specific cells

TCR Down-Regulation Controls Virus-Specific CD8+ T Cell Responses

DEFF Research Database (Denmark)

Bonefeld, Charlotte Menné; Haks, Mariëlle; Nielsen, Bodil

2008-01-01

The CD3gamma di-leucine-based motif plays a central role in TCR down-regulation. However, little is understood about the role of the CD3gamma di-leucine-based motif in physiological T cell responses. In this study, we show that the expansion in numbers of virus-specific CD8(+) T cells is impaired...... in mice with a mutated CD3gamma di-leucine-based motif. The CD3gamma mutation did not impair early TCR signaling, nor did it compromise recruitment or proliferation of virus-specific T cells, but it increased the apoptosis rate of the activated T cells by increasing down-regulation of the antiapoptotic...... molecule Bcl-2. This resulted in a 2-fold reduction in the clonal expansion of virus-specific CD8(+) T cells during the acute phase of vesicular stomatitis virus and lymphocytic choriomeningitis virus infections. These results identify an important role of CD3gamma-mediated TCR down-regulation in virus...

CELLISA: reporter cell-based immunization and screening of hybridomas specific for cell surface antigens.

Science.gov (United States)

Chen, Peter; Mesci, Aruz; Carlyle, James R

2011-01-01

Monoclonal antibodies (mAbs) specific for cell surface antigens are an invaluable tool to study immune receptor expression and function. Here, we outline a generalized reporter cell-based approach to the generation and high-throughput screening of mAbs specific for cell surface antigens. Termed CELLISA, this technology hinges upon the capture of hybridoma supernatants in mAb arrays that facilitate ligation of an antigen of interest displayed on BWZ reporter cells in the form of a CD3ζ-fusion chimeric antigen receptor (zCAR); in turn, specific mAb-mediated cross-linking of zCAR on BWZ cells results in the production of β-galactosidase enzyme (β-gal), which can be assayed colorimetrically. Importantly, the BWZ reporter cells bearing the zCAR of interest may be used for immunization as well as screening. In addition, serial immunizations employing additional zCAR- or native antigen-bearing cell lines can be used to increase the frequency of the desired antigen-specific hybridomas. Finally, the use of a cohort of epitope-tagged zCAR (e.g., zCAR(FLAG)) variants allows visualization of the cell surface antigen prior to immunization, and coimmunization using these variants can be used to enhance the immunogenicity of the target antigen. Employing the CELLISA strategy, we herein describe the generation of mAb directed against an uncharacterized natural killer cell receptor protein.

Leukomogenic factors downregulate heparanase expression in acute myeloid leukemia cells

International Nuclear Information System (INIS)

Eshel, Rinat; Ben-Zaken, Olga; Vainas, Oded; Nadir, Yona; Minucci, Saverio; Polliack, Aaron; Naparstek, Ella; Vlodavsky, Israel; Katz, Ben-Zion

2005-01-01

Heparanase is a heparan sulfate-degrading endoglycosidase expressed by mature monocytes and myeloid cells, but not by immature hematopoietic progenitors. Heparanase gene expression is upregulated during differentiation of immature myeloid cells. PML-RARα and PLZF-RARα fusion gene products associated with acute promyelocytic leukemia abrogate myeloid differentiation and heparanase expression. AML-Eto, a translocation product associated with AML FAB M2, also downregulates heparanase gene expression. The common mechanism that underlines the activity of these three fusion gene products involves the recruitment of histone deacetylase complexes to specific locations within the DNA. We found that retinoic acid that dissociates PML-RARα from the DNA, and which is used to treat acute promyelocytic leukemia patients, restores heparanase expression to normal levels in an acute promyelocytic leukemia cell line. The retinoic acid effects were also observed in primary acute promyelocytic leukemia cells and in a retinoic acid-treated acute promyelocytic leukemia patient. Histone deacetylase inhibitor reverses the downregulation of heparanase expression induced by the AML-Eto fusion gene product in M2 type AML. In summary, we have characterized a link between leukomogenic factors and the downregulation of heparanase in myeloid leukemic cells

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

Science.gov (United States)

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.

Adoptive cancer immunotherapy using DNA-demethylated T helper cells as antigen-presenting cells

DEFF Research Database (Denmark)

Kirkin, Alexei F.; Dzhandzhugazyan, Karine N.; Guldberg, Per

2018-01-01

In cancer cells, cancer/testis (CT) antigens become epigenetically derepressed through DNA demethylation and constitute attractive targets for cancer immunotherapy. Here we report that activated CD4+ T helper cells treated with a DNA-demethylating agent express a broad repertoire of endogenous CT...... antigens and can be used as antigen-presenting cells to generate autologous cytotoxic T lymphocytes (CTLs) and natural killer cells. In vitro, activated CTLs induce HLA-restricted lysis of tumor cells of different histological types, as well as cells expressing single CT antigens. In a phase 1 trial of 25...... patients with recurrent glioblastoma multiforme, cytotoxic lymphocytes homed to the tumor, with tumor regression ongoing in three patients for 14, 22, and 27 months, respectively. No treatment-related adverse effects were observed. This proof-of-principle study shows that tumor-reactive effector cells can...

Comparison of antigen-specific T-cell responses of tuberculosis patients using complex or single antigens of Mycobacterium tuberculosis

DEFF Research Database (Denmark)

Mustafa, A S; Amoudy, H A; Wiker, H G

1998-01-01

We have screened peripheral blood mononuclear cells (PBMC) from tuberculosis (TB) patients for proliferative reactivity and interferon-gamma (IFN-gamma) secretion against a panel of purified recombinant (r) and natural (n) culture filtrate (rESAT-6, nMPT59, nMPT64 and nMPB70) and somatic-derived (r......GroES, rPstS, rGroEL and rDnaK) antigens of Mycobacterium tuberculosis. The responses of PBMC to these defined antigens were compared with the corresponding results obtained with complex antigens, such as whole-cell M. tuberculosis, M. tuberculosis culture filtrate (MT-CF) and cell wall antigens, as well...... as the vaccine strain, Mycobacterium bovis bacillus Calmette-Guerin (BCG). In addition, M. tuberculosis and MT-CF-induced T-cell lines were tested in the same assays against the panel of purified and complex antigens. The compiled data from PBMC and T-cell lines tested for antigen-induced proliferation and IFN...

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

Science.gov (United States)

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.

Identification of a novel dendritic cell surface antigen defined by carbohydrate specific CD24 antibody cross-reactivity.

Science.gov (United States)

Williams, L A; McLellan, A D; Summers, K L; Sorg, R V; Fearnley, D B; Hart, D N

1996-01-01

Dendritic cells (DC) are characterized as leucocytes that lack mature lineage specific markers and stimulate naive T-lymphocyte proliferation in vitro and in vivo. The mouse heat stable antigen (HSA) participates in T lymphocyte co-stimulation and is expressed by DC isolated from thymus, skin and spleen. The human HSA homologue, CD24, is predominantly expressed by B lymphocytes and granulocytes, but its expression on DC has not been studied in detail. CD24 clearly participates in B-lymphocyte signalling but co-stimulatory activity for T lymphocytes has not yet been described. We have examined the expression of CD24 on human peripheral blood DC populations isolated directly or following in vitro culture. The CD24 antigen was absent from blood DC however, cross-reactive sialylated carbohydrate epitopes were detected on DC with some CD24 monoclonal antibodies (mAb). These CD24 mAb define a protein surface antigen, which is expressed by an immature or resting subpopulation of peripheral blood DC and is down-regulated following activation differentiation in vitro. PMID:8911149

Specificity of antigens on UV radiation-induced antigenic tumor cell variants measured in vitro and in vivo

International Nuclear Information System (INIS)

Hostetler, L.W.; Romerdahl, C.A.; Kripke, M.L.

1989-01-01

The purpose of this study was to determine whether antigenic variants cross-react immunologically with the parental tumor and whether the UVR-associated antigen unique to UVR-induced tumors is also present on the variants. Antigenic (regressor) variants and nonimmunogenic (progressor) clones derived from UV-irradiated cultures of the C3H K1735 melanoma and SF19 spontaneous fibrosarcoma cell lines were used to address these questions. In an in vivo immunization and challenge assay, the antigenic variants did not induce cross-protection among themselves, but each induced immunity against the immunizing variant, the parent tumor cells, and nonimmunogenic clones derived from UV-irradiated parent cultures. Therefore, the variants can be used to induce in mice a protective immunity that prevents the growth of the parent tumor and nonimmunogenic clones, but not other antigenic variants. In contrast, immunization with cells of the parental tumor or the nonimmunogenic clones induced no protective immunity against challenge with any of the cell lines. Utilizing the K1735 melanoma-derived cell lines in vitro, T-helper (Th) cells isolated from tumor-immunized mice were tested for cross-reactivity by their ability to collaborate with trinitrophenyl-primed B-cells in the presence of trinitrophenyl-conjugated tumor cells. Also, the cross-reactivity of cytotoxic T-lymphocytes from tumor-immunized mice was assessed by a 4-h 51Cr-release assay. Antigenic variants induced cytotoxic T-lymphocytes and Th activity that was higher than that induced by the parent tumor and nonimmunogenic clones from the UVR-exposed parent tumor and cross-reacted with the parental tumor cells and nonimmunogenic clones, but not with other antigenic variants

Nuclear localization of Merkel cell polyomavirus large T antigen in Merkel cell carcinoma

International Nuclear Information System (INIS)

Nakamura, Tomoyuki; Sato, Yuko; Watanabe, Daisuke; Ito, Hideki; Shimonohara, Nozomi; Tsuji, Takahiro; Nakajima, Noriko; Suzuki, Yoshio; Matsuo, Koma; Nakagawa, Hidemi; Sata, Tetsutaro; Katano, Harutaka

2010-01-01

To clarify whether mutations in the large T gene encoded by Merkel cell polyomavirus affect the expression and function of large T antigen in Merkel cell carcinoma cases, we investigated the expression of large T antigen in vitro and in vivo. Immunohistochemistry using a rabbit polyclonal antibody revealed that large T antigen was expressed in the nuclei of Merkel cell carcinoma cells with Merkel cell polyomavirus infection. Deletion mutant analyses identified an Arg-Lys-Arg-Lys sequence (amino acids 277-280) as a nuclear localization signal in large T antigen. Sequence analyses revealed that there were no mutations in the nuclear localization signal in any of the eleven Merkel cell polyomavirus strains examined. Furthermore, stop codons were not observed in the upstream of the nuclear localization signal in any of the Merkel cell carcinoma cases examined. These data suggest that the nuclear localization signal is highly conserved and functional in Merkel cell carcinoma cases.

Effector CD4+ T cells recognize intravascular antigen presented by patrolling monocytes.

Science.gov (United States)

Westhorpe, Clare L V; Norman, M Ursula; Hall, Pam; Snelgrove, Sarah L; Finsterbusch, Michaela; Li, Anqi; Lo, Camden; Tan, Zhe Hao; Li, Songhui; Nilsson, Susan K; Kitching, A Richard; Hickey, Michael J

2018-02-21

Although effector CD4 + T cells readily respond to antigen outside the vasculature, how they respond to intravascular antigens is unknown. Here we show the process of intravascular antigen recognition using intravital multiphoton microscopy of glomeruli. CD4 + T cells undergo intravascular migration within uninflamed glomeruli. Similarly, while MHCII is not expressed by intrinsic glomerular cells, intravascular MHCII-expressing immune cells patrol glomerular capillaries, interacting with CD4 + T cells. Following intravascular deposition of antigen in glomeruli, effector CD4 + T-cell responses, including NFAT1 nuclear translocation and decreased migration, are consistent with antigen recognition. Of the MHCII + immune cells adherent in glomerular capillaries, only monocytes are retained for prolonged durations. These cells can also induce T-cell proliferation in vitro. Moreover, monocyte depletion reduces CD4 + T-cell-dependent glomerular inflammation. These findings indicate that MHCII + monocytes patrolling the glomerular microvasculature can present intravascular antigen to CD4 + T cells within glomerular capillaries, leading to antigen-dependent inflammation.

Antigen Availability Shapes T Cell Differentiation and Function during Tuberculosis.

Science.gov (United States)

Moguche, Albanus O; Musvosvi, Munyaradzi; Penn-Nicholson, Adam; Plumlee, Courtney R; Mearns, Helen; Geldenhuys, Hennie; Smit, Erica; Abrahams, Deborah; Rozot, Virginie; Dintwe, One; Hoff, Søren T; Kromann, Ingrid; Ruhwald, Morten; Bang, Peter; Larson, Ryan P; Shafiani, Shahin; Ma, Shuyi; Sherman, David R; Sette, Alessandro; Lindestam Arlehamn, Cecilia S; McKinney, Denise M; Maecker, Holden; Hanekom, Willem A; Hatherill, Mark; Andersen, Peter; Scriba, Thomas J; Urdahl, Kevin B

2017-06-14

CD4 T cells are critical for protective immunity against Mycobacterium tuberculosis (Mtb), the cause of tuberculosis (TB). Yet to date, TB vaccine candidates that boost antigen-specific CD4 T cells have conferred little or no protection. Here we examined CD4 T cell responses to two leading TB vaccine antigens, ESAT-6 and Ag85B, in Mtb-infected mice and in vaccinated humans with and without underlying Mtb infection. In both species, Mtb infection drove ESAT-6-specific T cells to be more differentiated than Ag85B-specific T cells. The ability of each T cell population to control Mtb in the lungs of mice was restricted for opposite reasons: Ag85B-specific T cells were limited by reduced antigen expression during persistent infection, whereas ESAT-6-specific T cells became functionally exhausted due to chronic antigenic stimulation. Our findings suggest that different vaccination strategies will be required to optimize protection mediated by T cells recognizing antigens expressed at distinct stages of Mtb infection. Copyright © 2017 Elsevier Inc. All rights reserved.

Ascaris Suum Infection Downregulates Inflammatory Pathways in the Pig Intestine In Vivo and in Human Dendritic Cells In Vitro

DEFF Research Database (Denmark)

Midttun, Helene L. E.; Acevedo, Nathalie; Skallerup, Per

2018-01-01

similar transcriptional pathways in human dendritic cells (DCs) in vitro. DCs exposed to ABF secreted minimal amounts of cytokines and had impaired production of cyclooxygengase-2, altered glucose metabolism, and reduced capacity to induce interferon-gamma production in T cells. Our in vivo and in vitro......Ascaris suum is a helminth parasite of pigs closely related to its human counterpart, A. lumbricoides, which infects almost 1 billion people. Ascaris is thought to modulate host immune and inflammatory responses, which may drive immune hyporesponsiveness during chronic infections. Using...... transcriptomic analysis, we show here that pigs with a chronic A. suum infection have a substantial suppression of inflammatory pathways in the intestinal mucosa, with a broad downregulation of genes encoding cytokines and antigen-processing and costimulatory molecules. A. suum body fluid (ABF) suppressed...

Antigen-specific cytotoxic T cell and antigen-specific proliferating T cell clones can be induced to cytolytic activity by monoclonal antibodies against T3

NARCIS (Netherlands)

Spits, H.; Yssel, H.; Leeuwenberg, J.; de Vries, J. E.

1985-01-01

T3 is a human differentiation antigen expressed exclusively on mature T cells. In this study it is shown that anti-T3 monoclonal antibodies, in addition to their capacity to induce T cells to proliferate, are able to induce antigen-specific cytotoxic T lymphocyte clones to mediate antigen

Downregulation of IL-12 and a novel negative feedback system mediated by CD25+CD4+ T cells

International Nuclear Information System (INIS)

Sato, Kojiro; Tateishi, Shoko; Kubo, Kanae; Mimura, Toshihide; Yamamoto, Kazuhiko; Kanda, Hiroko

2005-01-01

CD25 + CD4 + regulatory T cells suppress immune responses and are believed to play roles in preventing autoimmune diseases. However, the mechanism(s) underlying the suppression and the regulation of their homeostasis remain to be elucidated. Here we show that these regulatory T cells downregulated CD25 - CD4 + T-cell-mediated production of IL-12 from antigen-presenting cells, which can act as a growth factor for CD25 - CD4 + T cells. We further found that CD25 + CD4 + T cells, despite their well-documented 'anergic' nature, proliferate significantly in vitro only when CD25 - CD4 + T cells are present. Notably, this proliferation was strongly dependent on IL-2 and relatively independent of IL-12. Thus, CD25 + CD4 + T cells suppress CD25 - CD4 + T-cell responses, at least in part, by inhibiting IL-12 production while they themselves can undergo proliferation with the mediation of CD25 - CD4 + T cells in vitro. These results offer a novel negative feedback system involving a tripartite interaction among CD25 + CD4 + and CD25 - CD4 + T cells, and APCs that may contribute to the termination of immune responses

Analysis of antigen-specific B-cell memory directly ex vivo.

Science.gov (United States)

McHeyzer-Williams, Louise J; McHeyzer-Williams, Michael G

2004-01-01

Helper T-cell-regulated B-cell memory develops in response to initial antigen priming as a cellular product of the germinal center (GC) reaction. On antigen recall, memory response precursors expand rapidly with exaggerated differentiation into plasma cells to produce the high-titer, high-affinity antibody(Ab) that typifies the memory B-cell response in vivo. We have devised a high-resolution flow cytometric strategy to quantify the emergence and maintenance of antigen-specific memory B cells directly ex vivo. Extended cell surface phenotype establishes a level of cellular diversity not previously appreciated for the memory B-cell compartment. Using an "exclusion transfer" strategy, we ascertain the capacity of two distinct memory B-cell populations to transfer antigen-specific memory into naive adoptive hosts. Finally, we sequence expressed messenger ribonucleic acid (mRNA) from single cells within the population to estimate the level of somatic hypermutation as the best molecular indicator of B-cell memory. In this chapter, we describe the methods used in each of these four sections that serve to provide high-resolution quantification of antigen-specific B-cell memory responses directly ex vivo.

Microfluidic squeezing for intracellular antigen loading in polyclonal B-cells as cellular vaccines

Science.gov (United States)

Lee Szeto, Gregory; van Egeren, Debra; Worku, Hermoon; Sharei, Armon; Alejandro, Brian; Park, Clara; Frew, Kirubel; Brefo, Mavis; Mao, Shirley; Heimann, Megan; Langer, Robert; Jensen, Klavs; Irvine, Darrell J.

2015-05-01

B-cells are promising candidate autologous antigen-presenting cells (APCs) to prime antigen-specific T-cells both in vitro and in vivo. However to date, a significant barrier to utilizing B-cells as APCs is their low capacity for non-specific antigen uptake compared to “professional” APCs such as dendritic cells. Here we utilize a microfluidic device that employs many parallel channels to pass single cells through narrow constrictions in high throughput. This microscale “cell squeezing” process creates transient pores in the plasma membrane, enabling intracellular delivery of whole proteins from the surrounding medium into B-cells via mechano-poration. We demonstrate that both resting and activated B-cells process and present antigens delivered via mechano-poration exclusively to antigen-specific CD8+T-cells, and not CD4+T-cells. Squeezed B-cells primed and expanded large numbers of effector CD8+T-cells in vitro that produced effector cytokines critical to cytolytic function, including granzyme B and interferon-γ. Finally, antigen-loaded B-cells were also able to prime antigen-specific CD8+T-cells in vivo when adoptively transferred into mice. Altogether, these data demonstrate crucial proof-of-concept for mechano-poration as an enabling technology for B-cell antigen loading, priming of antigen-specific CD8+T-cells, and decoupling of antigen uptake from B-cell activation.

Chloroquine inhibits accessory cell presentation of soluble natural and synthetic protein antigens

DEFF Research Database (Denmark)

Buus, S; Werdelin, O

1984-01-01

We have studied the in vitro effect of the lysosomotrophic agent, chloroquine, on the presentation of soluble protein antigens by guinea pig accessory cells. Chloroquine inhibited the capacity of antigen-pulsed accessory cells to stimulate proliferation in appropriately primed T cells. The effect...... was time- and dose-dependent. A brief treatment solely of the accessory cells with the drug compromised their ability to stimulate primed T cells in a subsequent culture provided the accessory cells were treated with chloroquine before their exposure to the antigen. These results suggest that chloroquine...... acts on an early event in the antigen handling by accessory cells. Chloroquine is a well known inhibitor of lysosomal proteolysis, and it is likely that its effect on antigen presentation is caused by an inhibition of antigen degradation....

A sub-population of circulating porcine gammadelta T cells can act as professional antigen presenting cells.

Science.gov (United States)

Takamatsu, H-H; Denyer, M S; Wileman, T E

2002-09-10

A sub-population of circulating porcine gammadelta T cells express cell surface antigens associated with antigen presenting cells (APCs), and are able to take up soluble antigen very effectively. Functional antigen presentation by gammadelta T cells to memory helper T cells was studied by inbred pig lymphocytes immunised with ovalbumin (OVA). After removing all conventional APCs from the peripheral blood of immunised pigs, the remaining lymphocytes still proliferated when stimulated with OVA. When gammadelta T cells were further depleted, OVA specific proliferation was abolished, but reconstitution with gammadelta T cells restored proliferation. The proliferation was blocked by monoclonal antibodies (mAb) against MHC class II or CD4, and by pre-treatment of gammadelta T cells with chloroquine. These results indicate that a sub-population of circulating porcine gammadelta T cells act as APCs and present antigen via MHC class II.

Effective antigen presentation to helper T cells by human eosinophils.

Science.gov (United States)

Farhan, Ruhaifah K; Vickers, Mark A; Ghaemmaghami, Amir M; Hall, Andrew M; Barker, Robert N; Walsh, Garry M

2016-12-01

Although eosinophils are inflammatory cells, there is increasing attention on their immunomodulatory roles. For example, murine eosinophils can present antigen to CD4 + T helper (Th) cells, but it remains unclear whether human eosinophils also have this ability. This study determined whether human eosinophils present a range of antigens, including allergens, to activate Th cells, and characterized their expression of MHC class II and co-stimulatory molecules required for effective presentation. Human peripheral blood eosinophils purified from non-allergic donors were pulsed with the antigens house dust mite extract (HDM), Timothy Grass extract (TG) or Mycobacterium tuberculosis purified protein derivative (PPD), before co-culture with autologous CD4 + Th cells. Proliferative and cytokine responses were measured, with eosinophil expression of HLA-DR/DP/DQ and the co-stimulatory molecules CD40, CD80 and CD86 determined by flow cytometry. Eosinophils pulsed with HDM, TG or PPD drove Th cell proliferation, with the response strength dependent on antigen concentration. The cytokine responses varied with donor and antigen, and were not biased towards any particular Th subset, often including combinations of pro- and anti-inflammatory cytokines. Eosinophils up-regulated surface expression of HLA-DR/DP/DQ, CD80, CD86 and CD40 in culture, increases that were sustained over 5 days when incubated with antigens, including HDM, or the major allergens it contains, Der p I or Der p II. Human eosinophils can, therefore, act as effective antigen-presenting cells to stimulate varied Th cell responses against a panel of antigens including HDM, TG or PPD, an ability that may help to determine the development of allergic disease. © 2016 John Wiley & Sons Ltd.

Kefiran suppresses antigen-induced mast cell activation.

Science.gov (United States)

Furuno, Tadahide; Nakanishi, Mamoru

2012-01-01

Kefir is a traditional fermented milk beverage produced by kefir grains in the Caucasian countries. Kefiran produced by Lactobacillus kefiranofaciens in kefir grains is an exopolysaccharide having a repeating structure with glucose and galactose residues in the chain sequence and has been suggested to exert many health-promoting effects such as immunomodulatory, hypotensive, hypocholesterolemic activities. Here we investigated the effects of kefiran on mast cell activation induced by antigen. Pretreatment with kefiran significantly inhibited antigen-induced Ca(2+) mobilization, degranulation, and tumor necrosis factor-α production in bone marrow-derived mast cells (BMMCs) in a dose-dependent manner. The phosphorylation of Akt, glycogen synthase kinase 3β, and extracellular signal-regulated kinases (ERKs) after antigen stimulation was also suppressed by pretreatment of BMMCs with kefiran. These findings indicate that kefiran suppresses mast cell degranulation and cytokine production by inhibiting the Akt and ERKs pathways, suggesting an anti-inflammatory effect for kefiran.

Detection of Avian Antigen-Specific T Cells Induced by Viral Vaccines

DEFF Research Database (Denmark)

Dalgaard, Tina Sørensen; Norup, Liselotte Rothmann; Juul-Madsen, Helle Risdahl

2016-01-01

Live attenuated viral vaccines are widely used in commercial poultry production, but the development of new effective inactivated/subunit vaccines is needed. Studies of avian antigen-specific T cells are primarily based on analyses ex vivo after activating the cells with recall antigen. There is ......Live attenuated viral vaccines are widely used in commercial poultry production, but the development of new effective inactivated/subunit vaccines is needed. Studies of avian antigen-specific T cells are primarily based on analyses ex vivo after activating the cells with recall antigen...

Chimeric antigen receptor-modified T cells for acute lymphoid leukemia.

Science.gov (United States)

Grupp, Stephan A; Kalos, Michael; Barrett, David; Aplenc, Richard; Porter, David L; Rheingold, Susan R; Teachey, David T; Chew, Anne; Hauck, Bernd; Wright, J Fraser; Milone, Michael C; Levine, Bruce L; June, Carl H

2013-04-18

Chimeric antigen receptor-modified T cells with specificity for CD19 have shown promise in the treatment of chronic lymphocytic leukemia (CLL). It remains to be established whether chimeric antigen receptor T cells have clinical activity in acute lymphoblastic leukemia (ALL). Two children with relapsed and refractory pre-B-cell ALL received infusions of T cells transduced with anti-CD19 antibody and a T-cell signaling molecule (CTL019 chimeric antigen receptor T cells), at a dose of 1.4×10(6) to 1.2×10(7) CTL019 cells per kilogram of body weight. In both patients, CTL019 T cells expanded to a level that was more than 1000 times as high as the initial engraftment level, and the cells were identified in bone marrow. In addition, the chimeric antigen receptor T cells were observed in the cerebrospinal fluid (CSF), where they persisted at high levels for at least 6 months. Eight grade 3 or 4 adverse events were noted. The cytokine-release syndrome and B-cell aplasia developed in both patients. In one child, the cytokine-release syndrome was severe; cytokine blockade with etanercept and tocilizumab was effective in reversing the syndrome and did not prevent expansion of chimeric antigen receptor T cells or reduce antileukemic efficacy. Complete remission was observed in both patients and is ongoing in one patient at 11 months after treatment. The other patient had a relapse, with blast cells that no longer expressed CD19, approximately 2 months after treatment. Chimeric antigen receptor-modified T cells are capable of killing even aggressive, treatment-refractory acute leukemia cells in vivo. The emergence of tumor cells that no longer express the target indicates a need to target other molecules in addition to CD19 in some patients with ALL.

Merkel cell polyomavirus in Merkel cell carcinogenesis: small T antigen-mediates c-Jun phosphorylation.

Science.gov (United States)

Wu, Julie H; Simonette, Rebecca A; Nguyen, Harrison P; Rady, Peter L; Tyring, Stephen K

2016-06-01

Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine skin cancer associated with the Merkel cell polyomavirus (MCPyV). The MCPyV genome, which is clonally integrated in the majority of MCCs, encodes the regulatory small T (sT) antigen. Previously, reports have established MCPyV sT antigen as a potent oncogene capable of inducing cell transformation. In the current study, we demonstrate a distinct role for c-Jun hyperactivation in MCPyV sT antigen pathogenesis. As MCPyV sT antigen's association with aggressive cancer growth has been previously established, this finding may represent a potential therapeutic target for the treatment of MCCs.

Downregulation of HIF-1a sensitizes U251 glioma cells to the temozolomide (TMZ) treatment

Energy Technology Data Exchange (ETDEWEB)

Tang, Jun-Hai [Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037 (China); Ma, Zhi-Xiong [National Institute of Biological Sciences, Beijing 102206 (China); Huang, Guo-Hao; Xu, Qing-Fu; Xiang, Yan [Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037 (China); Li, Ningning; Sidlauskas, Kastytis [Division of Neuropathology and Department of Neurodegenerative Disease, Institute of Neurology, University College London, London WC1N 3BG (United Kingdom); Zhang, Eric Erquan [National Institute of Biological Sciences, Beijing 102206 (China); Lv, Sheng-Qing, E-mail: lvsq0518@hotmail.com [Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037 (China)

2016-05-01

Purpose: The aim of this study was to investigate the effect of downregulation of HIF-1α gene on human U251 glioma cells and examine the consequent changes of TMZ induced effects and explore the molecular mechanisms. Methods: U251 cell line stably expressing HIF-1α shRNA was acquired via lentiviral vector transfection. The mRNA and protein expression alterations of genes involved in our study were determined respectively by qRT-PCR and Western blot. Cell proliferation was measured by MTT assay and colony formation assay, cell invasion/migration capacity was determined by transwell invasion assay/wound healing assay, and cell apoptosis was detected by flow cytometry. Results: We successfully established a U251 cell line with highly efficient HIF-1α knockdown. HIF-1a downregulation sensitized U251 cells to TMZ treatment and enhanced the proliferation-inhibiting, invasion/migration-suppressing, apoptosis-inducing and differentiation-promoting effects exerted by TMZ. The related molecular mechanisms demonstrated that expression of O{sup 6}-methylguanine DNA methyltransferase gene (MGMT) and genes of Notch1 pathway were significantly upregulated by TMZ treatment. However, this upregulation was abrogated by HIF-1α knockdown. We further confirmed important regulatory roles of HIF-1α in the expression of MGMT and activation of Notch1 pathways. Conclusion: HIF-1α downregulation sensitizes U251 glioma cells to the temozolomide treatment via inhibiting MGMT expression and Notch1 pathway activation. - Highlights: • TMZ caused more significant proliferation inhibition and apoptosis in U251 cells after downregulating HIF-1α. • Under TMZ treatment, HIF-1 downregulated U251 cells exhibited weaker mobility and more differentiated state. • TMZ caused MGMT over-expression and Notch1 pathway activation, which could be abrogated by HIF-1α downregulation.

Carbohydrates as T-cell antigens with implications in health and disease.

Science.gov (United States)

Sun, Lina; Middleton, Dustin R; Wantuch, Paeton L; Ozdilek, Ahmet; Avci, Fikri Y

2016-10-01

Glycosylation is arguably the most ubiquitous post-translational modification on proteins in microbial and mammalian cells. During the past few years, there has been intensive research demonstrating that carbohydrates, either in pure forms or in conjunction with proteins or lipids, evoke and modulate adaptive immune responses. We now know that carbohydrates can be directly recognized by T cells or participate in T-cell stimulation as components of T-cell epitopes. T-cell recognition of carbohydrate antigens takes place via their presentation by major histocompatibility complex pathways on antigen-presenting cells. In this review, we summarize studies on carbohydrates as T-cell antigens modulating adaptive immune responses. Through discussion of glycan-containing antigens, such as glycoproteins, glycolipids, zwitterionic polysaccharides and carbohydrate-based glycoconjugate vaccines, we will illustrate the key molecular and cellular interactions between carbohydrate antigens and T cells and the implications of these interactions in health and disease. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

TGF-β1 downregulates StAR expression and decreases progesterone production through Smad3 and ERK1/2 signaling pathways in human granulosa cells.

Science.gov (United States)

Fang, Lanlan; Chang, Hsun-Ming; Cheng, Jung-Chien; Leung, Peter C K; Sun, Ying-Pu

2014-11-01

Regulation of progesterone production in granulosa cells is important for normal reproductive functions. Steroidogenic acute regulatory protein (StAR) is recognized as the key regulatory protein involved in the rate-limiting step of steroidogenesis. TGF-β1 protein is detected in human follicular fluid, and TGF-β1 and its receptors are expressed in human granulosa cells. However, the functional role of TGF-β1 in the regulation of StAR expression and progesterone production in human granulosa cells remains unknown. Our objective was to investigate the effects of TGF-β1 on StAR expression and progesterone production in human granulosa cells. SVOG cells are human granulosa cells that were obtained from women undergoing in vitro fertilization and immortalized with SV40 large T antigen. SVOG cells were used to investigate the effects of TGF-β1 on StAR expression and progesterone production at an academic research center. Levels of mRNA and protein were examined by RT-qPCR and western blotting, respectively. The accumulation levels of progesterone were measured by enzyme-linked immunosorbent assay (ELISA). TGF-β1 treatment downregulated StAR expression and decreased progesterone production. The suppressive effects of TGF-β1 on StAR expression and progesterone production were abolished by the inhibition of TGF-β type I receptor. In addition, treatment with TGF-β1 activated the Smad2/3 and ERK1/2 signaling pathways. The inhibition of the Smad3 and ERK1/2 signaling pathways attenuated the TGF-β1-induced downregulation of StAR expression and progesterone production. TGF-β1 downregulated StAR expression and decreased progesterone production by activating the Smad3 and ERK1/2 signaling pathways in human granulosa cells.

Antigen dynamics of follicular dendritic cells

NARCIS (Netherlands)

Heesters, B.A.

2015-01-01

Stromal-derived follicular dendritic cells (FDCs) are a major depot for antigen that are essential for formation of germinal centers, the site where memory and effector B cells differentiate and high-affinity antibody production takes place. Historically, FDCs have been characterized as ‘accessory’

TCR down-regulation controls T cell homeostasis

DEFF Research Database (Denmark)

Boding, Lasse; Bonefeld, Charlotte Menné; Nielsen, Bodil L

2009-01-01

TCR and cytokine receptor signaling play key roles in the complex homeostatic mechanisms that maintain a relative stable number of T cells throughout life. Despite the homeostatic mechanisms, a slow decline in naive T cells is typically observed with age. The CD3gamma di-leucine-based motif...... controls TCR down-regulation and plays a central role in fine-tuning TCR expression and signaling in T cells. In this study, we show that the age-associated decline of naive T cells is strongly accelerated in CD3gammaLLAA knock-in mice homozygous for a double leucine to alanine mutation in the CD3gamma di......-leucine-based motif, whereas the number of memory T cells is unaffected by the mutation. This results in premature T cell population senescence with a severe dominance of memory T cells and very few naive T cells in middle-aged to old CD3gamma mutant mice. The reduced number of naive T cells in CD3gamma mutant mice...

Autoantibodies in autoimmune thyroid disease promote immune complex formation with self antigens and increase B cell and CD4+ T cell proliferation in response to self antigens

DEFF Research Database (Denmark)

Nielsen, Claus Henrik; Hegedüs, Laszlo; Leslie, Robert Graham Quinton

2004-01-01

's thyroiditis (HT), Graves' disease (GD) and healthy controls were incubated with human thyroglobulin (Tg) before adding normal peripheral blood mononuclear cells. The deposition of immunoglobulins and C3 fragments on B cells was then assessed. Inclusion of Tg in serum from HT patients promoted B cell capture......B cells are centrally involved as antigen-presenting cells in certain autoimmune diseases. To establish whether autoantibodies form immune complexes (IC) with self-antigens in autoimmune thyroid disease (AITD) and promote B cell uptake of self-antigen, sera from patients with Hashimoto...

Autoantibodies in autoimmune thyroid disease promote immune complex formation with self antigens and increase B cell and CD4+ T cell proliferation in response to self antigens

DEFF Research Database (Denmark)

Nielsen, Claus Henrik; Hegedüs, Laszlo; Leslie, Robert Graham Quinton

2004-01-01

B cells are centrally involved as antigen-presenting cells in certain autoimmune diseases. To establish whether autoantibodies form immune complexes (IC) with self-antigens in autoimmune thyroid disease (AITD) and promote B cell uptake of self-antigen, sera from patients with Hashimoto......'s thyroiditis (HT), Graves' disease (GD) and healthy controls were incubated with human thyroglobulin (Tg) before adding normal peripheral blood mononuclear cells. The deposition of immunoglobulins and C3 fragments on B cells was then assessed. Inclusion of Tg in serum from HT patients promoted B cell capture...

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

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

2017-06-01

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.

Stabilization of Transfected Cells Expressing Low-Incidence Blood Group Antigens: Novel Methods Facilitating Their Use as Reagent-Cells.

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Cecilia González

Full Text Available The identification of erythrocyte antibodies in the serum of patients rely on panels of human red blood cells (RBCs, which coexpress many antigens and are not easily available for low-incidence blood group phenotypes. These problems have been addressed by generating cell lines expressing unique blood group antigens, which may be used as an alternative to human RBCs. However, the use of cell lines implies several drawbacks, like the requirement of cell culture facilities and the high cost of cryopreservation. The application of cell stabilization methods could facilitate their use as reagent cells in clinical laboratories.We generated stably-transfected cells expressing low-incidence blood group antigens (Dia and Lua. High-expresser clones were used to assess the effect of TransFix® treatment and lyophilization as cell preservation methods. Cells were kept at 4°C and cell morphology, membrane permeability and antigenic properties were evaluated at several time-points after treatment.TransFix® addition to cell suspensions allows cell stabilization and proper antigen detection for at least 120 days, despite an increase in membrane permeability and a reduction in antigen expression levels. Lyophilized cells showed minor morphological changes and antigen expression levels were rather conserved at days 1, 15 and 120, indicating a high stability of the freeze-dried product. These stabilized cells have been proved to react specifically with human sera containing alloantibodies.Both stabilization methods allow long-term preservation of the transfected cells antigenic properties and may facilitate their distribution and use as reagent-cells expressing low-incidence antigens, overcoming the limited availability of such rare RBCs.

Ligation of major histocompatibility complex class I antigens (MHC-I) prevents apoptosis induced by Fas or SAPK/JNK activation in T-lymphoma cells

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Lamberth, K; Claesson, M H

2001-01-01

Early apoptosis in Jurkat T-lymphoma cells was induced by agonistic anti-Fas Ab or by anisomycin which activates the stress kinases SAPK/JNK. Apoptosis was inhibited by ligation of major histocompatibility complex class I antigens (MHC-I). MHC-I ligation induced upregulation of the anti-apoptotic......Early apoptosis in Jurkat T-lymphoma cells was induced by agonistic anti-Fas Ab or by anisomycin which activates the stress kinases SAPK/JNK. Apoptosis was inhibited by ligation of major histocompatibility complex class I antigens (MHC-I). MHC-I ligation induced upregulation of the anti......-apoptotic Bcl-2 protein and stabilized the mitochondrial membrane potential (Deltapsim). MHC-I ligation also prevented downregulation of Bcl-2 and destabilization of Deltapsim induced by anti-Fas Ab treatment or anisomycin exposure. Studies on three different Jurkat cell mutants deficient for src p56(lck), ZAP......-70 kinase, or TCR/CD3 gamma-chain showed that the cells undergo apoptosis after Fas ligation. Anisomycin exposure induced apoptosis in the src p56(lck)-deficient cell line but not in the two other mutant cell lines. Simultaneous cross-linking of MHC-I and Fas ligation inhibited apoptosis in the ZAP...

Limited transplantation of antigen-expressing hematopoietic stem cells induces long-lasting cytotoxic T cell responses.

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Warren L Denning

2011-02-01

Full Text Available Harnessing the ability of cytotoxic T lymphocytes (CTLs to recognize and eradicate tumor or pathogen-infected cells is a critical goal of modern immune-based therapies. Although multiple immunization strategies efficiently induce high levels of antigen-specific CTLs, the initial increase is typically followed by a rapid contraction phase resulting in a sharp decline in the frequency of functional CTLs. We describe a novel approach to immunotherapy based on a transplantation of low numbers of antigen-expressing hematopoietic stem cells (HSCs following nonmyeloablative or partially myeloablative conditioning. Continuous antigen presentation by a limited number of differentiated transgenic hematopoietic cells results in an induction and prolonged maintenance of fully functional effector T cell responses in a mouse model. Recipient animals display high levels of antigen-specific CTLs four months following transplantation in contrast to dendritic cell-immunized animals in which the response typically declines at 4-6 weeks post-immunization. Majority of HSC-induced antigen-specific CD8+ T cells display central memory phenotype, efficiently kill target cells in vivo, and protect recipients against tumor growth in a preventive setting. Furthermore, we confirm previously published observation that high level engraftment of antigen-expressing HSCs following myeloablative conditioning results in tolerance and an absence of specific cytotoxic activity in vivo. In conclusion, the data presented here supports potential application of immunization by limited transplantation of antigen-expressing HSCs for the prevention and treatment of cancer and therapeutic immunization of chronic infectious diseases such as HIV-1/AIDS.

Effect of radiation on the expression of tumor-associated antigens of human lung adenocarcinoma cells

International Nuclear Information System (INIS)

Hareyama, Masato

1988-01-01

We studied the effects of irradiation on the expression of a tumor-associated antigen (YH206 antigen) of cultured human lung adenocarcinoma A549 cells by using enzyme-linked immunosorbent assay (ELISA) and flow cytometry. YH206 antigen is preferentially expressed on adenocarcinoma cells. Irradiation of A549 cells remarkably increased the expression of YH206 antigen on the cell surface and the level of the antigen in the culture supernatant as well as in the cell lysate, whereas it significantly affected the expression of HLA (MHC-class I) antigen on the same cells. The expression of HLA antigen on the cell was also increased after treatment of the cells with interferon-γ. In an additional experiment, cells were stained simultaneously for surface antigens (fluorescein coupled antibodies) and for DNA content (propidium iodide), and then dual parameter measurements were performed by flow cytometry to analyse the relationship between antigen levels and the cell cycle. YH206 antigen and HLA antigen increased more in the S and G 2 /M phases of the cell cycle than in G 0 /G 1 . The expression of YH206 antigen was enhanced in the S and G 2 /M phases by irradiation, whereas the expression of HLA antigen was enhanced in each phase of the cell cycle with irradiation or IFN. These results suggest that irradiation plays a key role in the change of the expression of certain tumor-associated antigens. (author)

Cell surface expression level variation between two common Human Leukocyte Antigen alleles, HLA-A2 and HLA-B8, is dependent on the structure of the C terminal part of the alpha 2 and the alpha 3 domains

DEFF Research Database (Denmark)

Dellgren, Christoffer; Nehlin, Jan O; Barington, Torben

2015-01-01

Constitutive cell surface expression of Human Leukocyte Antigen (HLA) class I antigens vary extremely from tissue to tissue and individual antigens may differ widely in expression levels. Down-regulation of class I expression is a known immune evasive mechanism used by cancer cells and viruses....... Moreover, recent observations suggest that even minor differences in expression levels may influence the course of viral infections and the frequency of complications to stem cell transplantation. We have shown that some human multipotent stem cells have high expression of HLA-A while HLA-B is only weakly...... expressed, and demonstrate here that this is also the case for the human embryonic kidney cell line HEK293T. Using quantitative flow cytometry and quantitative polymerase chain reaction we found expression levels of endogenous HLA-A3 (median 71,204 molecules per cell) 9.2-fold higher than the expression of...

Effect of antigen on localization of immunologically specific B cells

International Nuclear Information System (INIS)

Ponzio, N.M.; Chapman, J.M.; Thorbecke, G.J.

1976-01-01

Studies were conducted to demonstrate homing of memory B cells to sites of antigen localization in lymph nodes, using functional criteria to detect local presence of memory cells at varying intervals after intravenous injection. Cell suspensions were prepared from spleens of donor mice injected with complete Freund's adjuvant. Recipient mice were injected with Escherichia coli endotoxin and immune or normal spleen cells and were gamma-irradiated. Results indicated that passively transferred unilateral B cell memory was established. The development over a period of several days of this difference between left and right lymph nodes suggests that recirculating memory B cells are being progressively selected by antigen in the lymph node, rather than that this difference is due to a specific exit of cells from the circulation towards the antigen

Shedding of leukemia-associated P24 antigen by lymphoblastoid cell lines.

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Komada, Y; Ochiai, H; Shimizu, K; Azuma, E; Kamiya, H; Sakurai, M

1987-12-01

We report the development of a unique enzyme-linked immunosorbent assay (ELISA) which makes possible the detection of leukemia-associated P24 antigen, utilizing its ability to bind the Ricinus communis agglutinin (RCA1) and a monoclonal antibody, SJ-9A4 simultaneously. Using the RCA1/SJ-9A4-ELISA, P24 antigen, as few as 50 X 10(3) cells from a common acute lymphoblastic leukemia (C-ALL) cell line could be detected. The presence of D-galactose gave complete and specific inhibition of P24 antigen binding to RCA1. Matched concentrations of D-glucose and D-sucrose had no effect on binding. The release of the P24 antigen into the culture medium by a C-ALL cell line maintained at 37 degrees C could be detected; however, no P24 antigen was present in the culture medium when the cells were maintained at 4 degrees C. Sequential analysis of the culture medium for soluble P24 antigen revealed that release of the P24 antigen associated with cell growth. Molecular sieve chromatography of concentrated culture medium indicated that shed P24 antigen was eluted in the macromolecule fraction. P24 antigen was detected in the cerebrospinal fluid (CSF) of four patients with P24 positive ALL at the time of relapse of the central nervous system (CNS) and was undetectable while in complete remission. The CSF from three patients with P24 negative ALL and three patients with aseptic meningitis had no detectable activity.

Impact of aging on antigen presentation cell function of dendritic cells.

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Wong, Christine; Goldstein, Daniel R

2013-08-01

Older people exhibit increased mortality to infections and cancer as compared to younger people, indicating that aging impairs immunity. Dendritic cells (DCs) are key for bridging the innate and adaptive arms of the immune system by priming antigen specific T cells. Discerning how aging impacts DC function to initiate adaptive immune responses is of great biomedical importance as this could lead to the development of novel therapeutics to enhance immunity with aging. This review details reports indicating that aging impairs the antigen presenting function of DCs but highlights other studies indicating preserved DC function with aging. How aging impacts antigen presentation by DCs is complex and without a clear unifying biological underpinning. Copyright © 2013 Elsevier Ltd. All rights reserved.

[The Effect of TALENs-mediated Downregulation Expression of Nanog on Malignant Behavior of Cervical Cancer HeLa Cells].

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Yu, Ai-qing; Li, Cheng-lin; Yang, Yi; Yan, Shi-rong

2016-01-01

To study the effect of downregulation expression of Nanog on malignant behavior of cervical cancer HeLa cells. Gene editing tool TALENs was employed to induce downregulation expression of Nanog, and Nanog mutation was evaluated by sequencing. RT-PCR and Western blot was used to detect the mRNA and protein expression level, respectively. Colony-formation assay, Transwell invasion assay, and chemotherapy sensibility assay was carried out to assess the capacity of colony-formation, invasion, and chemoresistance, respectively. TALENs successfully induced Nanog mutation and downregulated Nanog expression. Nanog mRNA and protein expression of Nanog-mutated monoclonal HeLa cells downregulated 3 times compared to thoses of wild-type HeLa cells (P HeLa cells were observed when compared to those of wild-type HeLa cells (P HeLa cells. Importantly, downregulation or silencing of Nanog is promising to be a novel strategy for the treatment of cervical carcinoma.

Ezrin dephosphorylation/downregulation contributes to ursolic acid-mediated cell death in human leukemia cells

International Nuclear Information System (INIS)

Li, G; Zhou, T; Liu, L; Chen, J; Zhao, Z; Peng, Y; Li, P; Gao, N

2013-01-01

Ezrin links the actin filaments with the cell membrane and has a functional role in the apoptotic process. It appears clear that ezrin is directly associated with Fas, leading to activation of caspase cascade and cell death. However, the exact role of ezrin in ursolic acid (UA)-induced apoptosis remains unclear. In this study, we show for the first time that UA induces apoptosis in both transformed and primary leukemia cells through dephosphorylation/downregulation of ezrin, association and polarized colocalization of Fas and ezrin, as well as formation of death-inducing signaling complex. These events are dependent on Rho-ROCK1 signaling pathway. Knockdown of ezrin enhanced cell death mediated by UA, whereas overexpression of ezrin attenuated UA-induced apoptosis. Our in vivo study also showed that UA-mediated inhibition of tumor growth of mouse leukemia xenograft model is in association with the dephosphorylation/downregulation of ezrin. Such findings suggest that the cytoskeletal protein ezrin may represent an attractive target for UA-mediated lethality in human leukemia cells

Dynamic imaging of experimental Leishmania donovani-induced hepatic granulomas detects Kupffer cell-restricted antigen presentation to antigen-specific CD8 T cells.

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Lynette Beattie

2010-03-01

Full Text Available Kupffer cells (KCs represent the major phagocytic population within the liver and provide an intracellular niche for the survival of a number of important human pathogens. Although KCs have been extensively studied in vitro, little is known of their in vivo response to infection and their capacity to directly interact with antigen-specific CD8(+ T cells. Here, using a combination of approaches including whole mount and thin section confocal microscopy, adoptive cell transfer and intra-vital 2-photon microscopy, we demonstrate that KCs represent the only detectable population of mononuclear phagocytes within granulomas induced by Leishmania donovani infection that are capable of presenting parasite-derived peptide to effector CD8(+ T cells. This restriction of antigen presentation to KCs within the Leishmania granuloma has important implications for the identification of new candidate vaccine antigens and for the design of novel immuno-therapeutic interventions.

Detection of proliferating cell nuclear antigens and interleukin-2 beta receptor molecules on mitogen- and antigen-stimulated lymphocytes.

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Hesketh, J; Dobbelaere, D; Griffin, J F; Buchan, G

1993-01-01

The expression of interleukin-2 receptors (IL-2R) and proliferating cell nuclear antigens (PCNA) were compared for their usefulness as markers of lymphocyte activation. Heterologous polyclonal (anti-bovine IL-2R) and monoclonal (anti-human PCNA) antibodies were used to detect the expression of these molecules on activated deer lymphocytes. Both molecules were co-expressed on blast cells which had been activated with mitogen [concanavalin A (Con A)]. There was detectable up-regulation of IL-2R expression in response to antigen [Mycobacterium bovis-derived purified protein derivative (PPD)] stimulation while PCNA expression mimicked lymphocyte transformation (LT) reactivity. PCNA expression was found to more accurately reflect both antigen- and mitogen-activated lymphocyte activation, as estimated by LT activity. The expression of PCNA was used to identify antigen reactive cells from animals exposed to M. bovis. A very low percentage (1.1 +/- 0.4%) of peripheral blood lymphocytes from non-infected animals could be stimulated to express PCNA by in vitro culture with antigen (PPD). Within the infected group both diseased and healthy, 'in-contact', animals expressed significantly higher levels of PCNA upon antigen stimulation. PMID:8104884

EVIR: chimeric receptors that enhance dendritic cell cross-dressing with tumor antigens.

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Squadrito, Mario Leonardo; Cianciaruso, Chiara; Hansen, Sarah K; De Palma, Michele

2018-03-01

We describe a lentivirus-encoded chimeric receptor, termed extracellular vesicle (EV)-internalizing receptor (EVIR), which enables the selective uptake of cancer-cell-derived EVs by dendritic cells (DCs). The EVIR enhances DC presentation of EV-associated tumor antigens to CD8 + T cells primarily through MHCI recycling and cross-dressing. EVIRs should facilitate exploring the mechanisms and implications of horizontal transfer of tumor antigens to antigen-presenting cells.

High hydrostatic pressure affects antigenic pool in tumor cells: Implication for dendritic cell-based cancer immunotherapy.

Science.gov (United States)

Urbanova, Linda; Hradilova, Nada; Moserova, Irena; Vosahlikova, Sarka; Sadilkova, Lenka; Hensler, Michal; Spisek, Radek; Adkins, Irena

2017-07-01

High hydrostatic pressure (HHP) can be used to generate dendritic cell (DC)-based active immunotherapy for prostate, lung and ovarian cancer. We showed here that HHP treatment of selected human cancer cell lines leads to a degradation of tumor antigens which depends on the magnitude of HHP applied and on the cancer cell line origin. Whereas prostate or ovarian cell lines displayed little protein antigen degradation with HHP treatment up to 300MPa after 2h, tumor antigens are hardly detected in lung cancer cell line after treatment with HHP 250MPa at the same time. On the other hand, quick reduction of tumor antigen-coding mRNA was observed at HHP 200MPa immediately after treatment in all cell lines tested. To optimize the DC-based active cellular therapy protocol for HHP-sensitive cell lines the immunogenicity of HHP-treated lung cancer cells at 150, 200 and 250MPa was compared. Lung cancer cells treated with HHP 150MPa display characteristics of immunogenic cell death, however cells are not efficiently phagocytosed by DC. Despite induction of the highest number of antigen-specific CD8 + T cells, 150 MPa-treated lung cancer cells survive in high numbers. This excludes their use in DC vaccine manufacturing. HHP of 200MPa treatment of lung cancer cells ensures the optimal ratio of efficient immunogenic killing and delivery of protein antigens in DC. These results represent an important pre-clinical data for generation of immunogenic killed lung cancer cells in ongoing NSCLC Phase I/II clinical trial using DC-based active cellular immunotherapy (DCVAC/LuCa). Copyright © 2017 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

Chimeric antigen receptor T-cell therapy for solid tumors

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Kheng Newick

2016-01-01

Full Text Available Chimeric antigen receptor (CAR T cells are engineered constructs composed of synthetic receptors that direct T cells to surface antigens for subsequent elimination. Many CAR constructs are also manufactured with elements that augment T-cell persistence and activity. To date, CAR T cells have demonstrated tremendous success in eradicating hematological malignancies (e.g., CD19 CARs in leukemias. This success is not yet extrapolated to solid tumors, and the reasons for this are being actively investigated. Here in this mini-review, we discuss some of the key hurdles encountered by CAR T cells in the solid tumor microenvironment.

Pattern of distribution of blood group antigens on human epidermal cells during maturation

DEFF Research Database (Denmark)

Dabelsteen, Erik; Buschard, Karsten; Hakomori, Sen-Itiroh

1984-01-01

The distribution in human epidermis of A, B, and H blood group antigens and of a precursor carbohydrate chain, N-acetyl-lactosamine, was examined using immunofluorescence staining techniques. The material included tissue from 10 blood group A, 4 blood group B, and 9 blood group O persons. Murine...... on the lower spinous cells whereas H antigen was seen predominantly on upper spinous cells or on the granular cells. Epithelia from blood group A or B persons demonstrated A or B antigens, respectively, but only if the tissue sections were trypsinized before staining. In such cases A or B antigens were found...... monoclonal antibodies were used to identify H antigen (type 2 chain) and N-acetyl-lactosamine. Human antisera were used to identify A and B antigens. In all groups N-acetyl-lactosamine and H antigen were found on the cell membranes of the spinous cell layer. N-acetyl-lactosamine was present mainly...

Downregulation of the expression of HDGF attenuates malignant biological behaviors of hilar cholangiocarcinoma cells.

Science.gov (United States)

Liu, Yanfeng; Sun, Jingxian; Yang, Guangyun; Liu, Zhaojian; Guo, Sen; Zhao, Rui; Xu, Kesen; Wu, Xiaopeng; Zhang, Zhaoyang

2015-09-01

Hepatoma-derived growth factor (HDGF) has been reported to be a potential predictive and prognostic marker for several types of cancer and important in malignant biological behaviors. However, its role in human hilar cholangiocarcinoma remains to be elucidated. Our previous study demonstrated that high expression levels of HDGF in hilar cholangiocarcinoma tissues correlates with tumor progression and patient outcome. The present study aimed to elucidate the detailed functions of the HDGF protein. This was performed by downregulating the protein expression of HDGF in the FRH0201 hilar cholangiocarcinoma cell line by RNA interference (RNAi) in vitro, and revealed that downregulation of the HDGF protein significantly inhibited the malignant biological behavior of the FRH0201 cells. In addition, further investigation revealed that downregulation of the protein expression of HDGF significantly decreased the secretion of vascular endothelial growth factor, which may be the mechanism partially responsible for the inhibition of malignant biological behaviors. These findings demonstrated that HDGF is important in promoting malignant biological behaviors, including proliferation, migration and invasion of hilar cholangiocarcinoma FRH0201 cells. Inhibition of the expression of HDGF downregulated the malignant biological behaviors, suggesting that downregulation of the protein expression of HDGF by RNAi may be a novel therapeutic approach to inhibit the progression of hilar cholangiocarcinoma.

Cytotoxic T lymphocyte recognition of HLA-A/B antigens introduced into EL4 cells by cell-liposome fusion.

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Engelhard, V H; Powers, G A; Moore, L C; Holterman, M J; Correa-Freire, M C

1984-01-01

HLA-A2 and -B7 antigens were introduced into EL4 (H-2b) cells by cell-liposome fusion and were used as targets or stimulators for cytotoxic T lymphocytes (CTL) generated in C57B1/6 (H-2b) mice. It was found that such EL4-HLA cells were not recognized by CTL that had been raised against either a human cell line bearing these HLA antigens or the purified HLA-A2 and -B7 antigens reconstituted into liposomes. In addition, EL4-HLA cells were not capable of inducing CTL that could recognize a human cell line bearing HLA-A2 and -B7 antigens. Instead, EL4-HLA cells induced CTL that specifically lysed EL4-HLA cells and not human cells expressing HLA-A2 and -B7. CTL recognition required the presence of HLA antigens on the EL4 cell surface and was inhibited by antibodies against either H-2b or HLA-A/B. Monoclonal antibody binding studies showed that the expected polymorphic determinants of the HLA-A2 and -B7 antigens were still present on EL4-HLA cells. However, the specificity of CTL or their precursors that are capable of recognizing HLA-A2 or -B7 was altered after these antigens became associated with the EL4 surface. Possible explanations for these results are discussed.

CARbodies: Human Antibodies Against Cell Surface Tumor Antigens Selected From Repertoires Displayed on T Cell Chimeric Antigen Receptors

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Vanesa Alonso-Camino

2013-01-01

Full Text Available A human single-chain variable fragment (scFv antibody library was expressed on the surface of human T cells after transduction with lentiviral vectors (LVs. The repertoire was fused to a first-generation T cell receptor ζ (TCRζ-based chimeric antigen receptor (CAR. We used this library to isolate antibodies termed CARbodies that recognize antigens expressed on the tumor cell surface in a proof-of-principle system. After three rounds of activation-selection there was a clear repertoire restriction, with the emergence dominant clones. The CARbodies were purified from bacterial cultures as soluble and active proteins. Furthermore, to validate its potential application for adoptive cell therapy, human T cells were transduced with a LV encoding a second-generation costimulatory CAR (CARv2 bearing the selected CARbodies. Transduced human primary T cells expressed significant levels of the CARbodies-based CARv2 fusion protein on the cell surface, and importantly could be specifically activated, after stimulation with tumor cells. This approach is a promising tool for the generation of antibodies fully adapted to the display format (CAR and the selection context (cell synapse, which could extend the scope of current adoptive cell therapy strategies with CAR-redirected T cells.

Pu-erh Tea Inhibits Tumor Cell Growth by Down-Regulating Mutant p53

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Zhao, Lanjun; Jia, Shuting; Tang, Wenru; Sheng, Jun; Luo, Ying

2011-01-01

Pu-erh tea is a kind of fermented tea with the incorporation of microorganisms’ metabolites. Unlike green tea, the chemical characteristics and bioactivities of Pu-erh tea are still not well understood. Using water extracts of Pu-erh tea, we analyzed the tumor cell growth inhibition activities on several genetically engineered mouse tumor cell lines. We found that at the concentration that did not affect wild type mouse embryo fibroblasts (MEFs) growth, Pu-erh tea extracts could inhibit tumor cell growth by down-regulated S phase and cause G1 or G2 arrest. Further study showed that Pu-erh tea extracts down-regulated the expression of mutant p53 in tumor cells at the protein level as well as mRNA level. The same concentration of Pu-erh tea solution did not cause p53 stabilization or activation of its downstream pathways in wild type cells. We also found that Pu-erh tea treatment could slightly down-regulate both HSP70 and HSP90 protein levels in tumor cells. These data revealed the action of Pu-erh tea on tumor cells and provided the possible mechanism for Pu-erh tea action, which explained its selectivity in inhibiting tumor cells without affecting wild type cells. Our data sheds light on the application of Pu-erh tea as an anti-tumor agent with low side effects. PMID:22174618

Antibody-antigen-adjuvant conjugates enable co-delivery of antigen and adjuvant to dendritic cells in cis but only have partial targeting specificity.

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Martin Kreutz

Full Text Available Antibody-antigen conjugates, which promote antigen-presentation by dendritic cells (DC by means of targeted delivery of antigen to particular DC subsets, represent a powerful vaccination approach. To ensure immunity rather than tolerance induction the co-administration of a suitable adjuvant is paramount. However, co-administration of unlinked adjuvant cannot ensure that all cells targeted by the antibody conjugates are appropriately activated. Furthermore, antigen-presenting cells (APC that do not present the desired antigen are equally strongly activated and could prime undesired responses against self-antigens. We, therefore, were interested in exploring targeted co-delivery of antigen and adjuvant in cis in form of antibody-antigen-adjuvant conjugates for the induction of anti-tumour immunity. In this study, we report on the assembly and characterization of conjugates consisting of DEC205-specific antibody, the model antigen ovalbumin (OVA and CpG oligodeoxynucleotides (ODN. We show that such conjugates are more potent at inducing cytotoxic T lymphocyte (CTL responses than control conjugates mixed with soluble CpG. However, our study also reveals that the nucleic acid moiety of such antibody-antigen-adjuvant conjugates alters their binding and uptake and allows delivery of the antigen and the adjuvant to cells partially independently of DEC205. Nevertheless, antibody-antigen-adjuvant conjugates are superior to antibody-free antigen-adjuvant conjugates in priming CTL responses and efficiently induce anti-tumour immunity in the murine B16 pseudo-metastasis model. A better understanding of the role of the antibody moiety is required to inform future conjugate vaccination strategies for efficient induction of anti-tumour responses.

Intestinal Epithelial Cells Modulate Antigen-Presenting Cell Responses to Bacterial DNA

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Campeau, J. L.; Salim, S. Y.; Albert, E. J.; Hotte, N.

2012-01-01

Intestinal epithelial cells and antigen-presenting cells orchestrate mucosal innate immunity. This study investigated the role of bacterial DNA in modulating epithelial and bone marrow-derived antigen-presenting cells (BM-APCs) and subsequent T-lymphocyte responses. Murine MODE-K epithelial cells and BM-APCs were treated with DNA from either Bifidobacterium breve or Salmonella enterica serovar Dublin directly and under coculture conditions with CD4+ T cells. Apical stimulation of MODE-K cells with S. Dublin DNA enhanced secretion of cytokines from underlying BM-APCs and induced interleukin-17 (IL-17) and gamma interferon (IFN-γ) secretion from CD4+ T cells. Bacterial DNA isolated from either strain induced maturation and increased cytokine secretion from BM-APCs. Conditioned medium from S. Dublin-treated MODE-K cells elicited an increase in cytokine secretion similar to that seen for S. Dublin DNA. Treatment of conditioned medium from MODE-K cells with RNase and protease prevented the S. Dublin-induced increased cytokine secretion. Oral feeding of mice with B. breve DNA resulted in enhanced levels of colonic IL-10 and transforming growth factor β (TGFβ) compared with what was seen for mice treated with S. Dublin DNA. In contrast, feeding mice with S. Dublin DNA increased levels of colonic IL-17 and IL-12p70. T cells from S. Dublin DNA-treated mice secreted high levels of IL-12 and IFN-γ compared to controls and B. breve DNA-treated mice. These results demonstrate that intestinal epithelial cells are able to modulate subsequent antigen-presenting and T-cell responses to bacterial DNA with pathogenic but not commensal bacterial DNA inducing effector CD4+ T lymphocytes. PMID:22615241

Conventional CD4+ T cells present bacterial antigens to induce cytotoxic and memory CD8+ T cell responses.

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Cruz-Adalia, Aránzazu; Ramirez-Santiago, Guillermo; Osuna-Pérez, Jesús; Torres-Torresano, Mónica; Zorita, Virgina; Martínez-Riaño, Ana; Boccasavia, Viola; Borroto, Aldo; Martínez Del Hoyo, Gloria; González-Granado, José María; Alarcón, Balbino; Sánchez-Madrid, Francisco; Veiga, Esteban

2017-11-17

Bacterial phagocytosis and antigen cross-presentation to activate CD8 + T cells are principal functions of professional antigen presenting cells. However, conventional CD4 + T cells also capture and kill bacteria from infected dendritic cells in a process termed transphagocytosis (also known as transinfection). Here, we show that transphagocytic T cells present bacterial antigens to naive CD8 + T cells, which proliferate and become cytotoxic in response. CD4 + T-cell-mediated antigen presentation also occurs in vivo in the course of infection, and induces the generation of central memory CD8 + T cells with low PD-1 expression. Moreover, transphagocytic CD4 + T cells induce protective anti-tumour immune responses by priming CD8 + T cells, highlighting the potential of CD4 + T cells as a tool for cancer immunotherapy.

Effects of low dose X-ray irradiation on antigen presentation and IL-12 secretion in human dendritic cells in vitro

International Nuclear Information System (INIS)

Yan Peng; Jiang Qisheng; Li Fengsheng; He Rui; Wang Cuilan; Li Xiao

2012-01-01

Objective: To explore the effects of low dose X-ray irradiation on the ability of antigen presentation and IL-12 secretion in human dendritic cells that had been cultured for different time in vitro. Methods: The human peripheral blood mononuclear cells (PBMC) were collected and differentiated to dendritic cells (DCs) by rhGM-CSF and rhIL-4 treatment in vitro. The DCs were divided into 3 groups, group A: DCs were cultured for 2 d and then irradiated with 0.05, 0.1, 0.2 and 0.5 Gy X-rays; group B: DCs were cultured for 6 d and then irradiated as above; group C:DCs were cultured without irradiation.At 8 d of cell culture, the DCs were applied to activate T cells and CCK-8 was used to detect MLR (mixed lymphocyte reaction), and the antigen presentation ability of DCs was evaluated. MTT assay was also used to test the cell-killing effect of the activated T-cells on A549 cells. IL-12 in the culture medium of DCs was detected by ELISA. Results: After irradiation with 0.2 and 0.5 Gy X-rays, the antigen presentation ability of DCs was decreased in group A (t=2.79 and 3.71, P<0.05), but significantly increased in group B (t=3.60 and 3.11, P<0.05). The ability of the T cell activation was detected and the proliferation of A549 cells was slightly inhibited by the DCs in group A (t=2.89 and 2.91, P<0.05), but was obviously inhibited by the DCs in group B (t=2.91 and 2.82, P<0.05). Meanwhile,the level of IL-12 was dramatically decreased in group A (t=4.44 and 6.93, P<0.05), but was increased in group B (t=3.51 and 4.12, P<0.05). Conclusions: The abilities of antigen presentation and proliferation inhibition of DCs could be down-regulated by low dose (<0.5 Gy) of X-ray irradiation at the early stage of DCs, but was up-regulated at the late stage of DCs culture. (authors)

Strategy for eliciting antigen-specific CD8+ T cell-mediated immune response against a cryptic CTL epitope of merkel cell polyomavirus large T antigen

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Gomez Bianca P

2012-10-01

Full Text Available Abstract Background Merkel cell carcinoma (MCC is a relatively new addition to the expanding category of oncovirus-induced cancers. Although still comparably rare, the number of cases has risen dramatically in recent years. Further complicating this trend is that MCC is an extremely aggressive neoplasm with poor patient prognosis and limited treatment options for advanced disease. The causative agent of MCC has been identified as the merkel cell polyomavirus (MCPyV. The MCPyV-encoded large T (LT antigen is an oncoprotein that is theorized to be essential for virus-mediated tumorigenesis and is therefore, an excellent MCC antigen for the generation of antitumor immune responses. As a foreign antigen, the LT oncoprotein avoids the obstacle of immune tolerance, which normally impedes the development of antitumor immunity. Ergo, it is an excellent target for anti-MCC immunotherapy. Since tumor-specific CD8+ T cells lead to better prognosis for MCC and numerous other cancers, we have generated a DNA vaccine that is capable of eliciting LT-specific CD8+ T cells. The DNA vaccine (pcDNA3-CRT/LT encodes the LT antigen linked to a damage-associated molecular pattern, calreticulin (CRT, as it has been demonstrated that the linkage of CRT to antigens promotes the induction of antigen-specific CD8+ T cells. Results The present study shows that DNA vaccine-induced generation of LT-specific CD8+ T cells is augmented by linking CRT to the LT antigen. This is relevant since the therapeutic effects of the pcDNA3-CRT/LT DNA vaccine is mediated by LT-specific CD8+ T cells. Mice vaccinated with the DNA vaccine produced demonstrably more LT-specific CD8+ T cells. The DNA vaccine was also able to confer LT-specific CD8+ T cell-mediated protective and therapeutic effects to prolong the survival of mice with LT-expressing tumors. In the interest of determining the LT epitope which most MCC-specific CD8+ T cells recognize, we identified the amino acid sequence of the

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

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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

Impact of MUC1 mucin downregulation in the phenotypic characteristics of MKN45 gastric carcinoma cell line.

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Natália R Costa

Full Text Available BACKGROUND: Gastric carcinoma is the second leading cause of cancer-associated death worldwide. The high mortality associated with this disease is in part due to limited knowledge about gastric carcinogenesis and a lack of available therapeutic and prevention strategies. MUC1 is a high molecular weight transmembrane mucin protein expressed at the apical surface of most glandular epithelial cells and a major component of the mucus layer above gastric mucosa. Overexpression of MUC1 is found in approximately 95% of human adenocarcinomas, where it is associated with oncogenic activity. The role of MUC1 in gastric cancer progression remains to be clarified. METHODOLOGY: We downregulated MUC1 expression in a gastric carcinoma cell line by RNA interference and studied the effects on cellular proliferation (MTT assay, apoptosis (TUNEL assay, migration (migration assay, invasion (invasion assay and aggregation (aggregation assay. Global gene expression was evaluated by microarray analysis to identify alterations that are regulated by MUC1 expression. In vivo assays were also performed in mice, in order to study the tumorigenicity of cells with and without MUC1 downregulation in MKN45 gastric carcinoma cell line. RESULTS: Downregulation of MUC1 expression increased proliferation and apoptosis as compared to controls, whereas cell-cell aggregation was decreased. No significant differences were found in terms of migration and invasion between the downregulated clones and the controls. Expression of TCN1, KLK6, ADAM29, LGAL4, TSPAN8 and SHPS-1 was found to be significantly different between MUC1 downregulated clones and the control cells. In vivo assays have shown that mice injected with MUC1 downregulated cells develop smaller tumours when compared to mice injected with the control cells. CONCLUSIONS: These results indicate that MUC1 downregulation alters the phenotype and tumorigenicity of MKN45 gastric carcinoma cells and also the expression of several

A population dynamics analysis of the interaction between adaptive regulatory T cells and antigen presenting cells.

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David Fouchet

Full Text Available BACKGROUND: Regulatory T cells are central actors in the maintenance of tolerance of self-antigens or allergens and in the regulation of the intensity of the immune response during infections by pathogens. An understanding of the network of the interaction between regulatory T cells, antigen presenting cells and effector T cells is starting to emerge. Dynamical systems analysis can help to understand the dynamical properties of an interaction network and can shed light on the different tasks that can be accomplished by a network. METHODOLOGY AND PRINCIPAL FINDINGS: We used a mathematical model to describe a interaction network of adaptive regulatory T cells, in which mature precursor T cells may differentiate into either adaptive regulatory T cells or effector T cells, depending on the activation state of the cell by which the antigen was presented. Using an equilibrium analysis of the mathematical model we show that, for some parameters, the network has two stable equilibrium states: one in which effector T cells are strongly regulated by regulatory T cells and another in which effector T cells are not regulated because the regulatory T cell population is vanishingly small. We then simulate different types of perturbations, such as the introduction of an antigen into a virgin system, and look at the state into which the system falls. We find that whether or not the interaction network switches from the regulated (tolerant state to the unregulated state depends on the strength of the antigenic stimulus and the state from which the network has been perturbed. CONCLUSION/SIGNIFICANCE: Our findings suggest that the interaction network studied in this paper plays an essential part in generating and maintaining tolerance against allergens and self-antigens.

Immune responses of dendritic cells after acquiring antigen from apoptotic hepatocholangioma cells caused by γ-ray

International Nuclear Information System (INIS)

Wu Gang; Gu Hongguang; Han Benli; Pei Xuetao

2002-01-01

Objective: To investigate the induction of cytotoxic T lymphocytes (CTLs) in antitumor responsiveness and therapeutic effects after dendritic cells (DCs) acquired antigen from apoptotic hepatocholangioma cells. Methods: DCs from blood mononuclear cells that maintain the characteristics of immaturity-anti-gen-capturing and-processing capacity were established in vitro by using granulocyte/macrophage colony-stimulating factor (GM-CSF) and interleukin-4. Then, apoptosis in hepatocholangioma cells was induced with γ-radiation. The experimental groups included (1) co-culture of DCs, and apoptotic cancer cells and T cells; (2) co-culture of DCs necrotic cancer cells and T cells; (3) co-culture of DCs-cultured cancer cell and T cells. These cells were co-cultured for 7 days. DCs and T cell were enriched separately. Finally, antitumor response test was carried out. Results: These cells had typical dendritic morphology, expressed high levels of CD1a, B7 and acquired antigen from apoptotic cells caused by γ-rays and induced an increased T cell-stimulatory capacity in MLR. Conclusions: DCs obtained from blood mononuclear cells using GM-CSF and IL-4 and DCs can efficiently present antigen driven from apoptotic cells caused by γ-rays and induce T cells increasing obviously. It can probably become an effective approach of DC transduction with antigen

Downregulation of hPMC2 imparts chemotherapeutic sensitivity to alkylating agents in breast cancer cells.

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Krishnamurthy, Nirmala; Liu, Lili; Xiong, Xiahui; Zhang, Junran; Montano, Monica M

2015-01-01

Triple negative breast cancer cell lines have been reported to be resistant to the cyotoxic effects of temozolomide (TMZ). We have shown previously that a novel protein, human homolog of Xenopus gene which Prevents Mitotic Catastrophe (hPMC2) has a role in the repair of estrogen-induced abasic sites. Our present study provides evidence that downregulation of hPMC2 in MDA-MB-231 and MDA-MB-468 breast cancer cells treated with temozolomide (TMZ) decreases cell survival. This increased sensitivity to TMZ is associated with an increase in number of apurinic/apyrimidinic (AP) sites in the DNA. We also show that treatment with another alkylating agent, BCNU, results in an increase in AP sites and decrease in cell survival. Quantification of western blot analyses and immunofluorescence experiments reveal that treatment of hPMC2 downregulated cells with TMZ results in an increase in γ-H2AX levels, suggesting an increase in double strand DNA breaks. The enhancement of DNA double strand breaks in TMZ treated cells upon downregulation of hPCM2 is also revealed by the comet assay. Overall, we provide evidence that downregulation of hPMC2 in breast cancer cells increases cytotoxicity of alkylating agents, representing a novel mechanism of treatment for breast cancer. Our data thus has important clinical implications in the management of breast cancer and brings forth potentially new therapeutic strategies.

Antigen-specific murine T cell clones produce soluble interleukin 2 receptor on stimulation with specific antigens

International Nuclear Information System (INIS)

Wagner, D.K.; York-Jolley, J.; Malek, T.R.; Berzofsky, J.A.; Nelson, D.L.

1986-01-01

In this study, monoclonal antibodies were used to the murine IL 2 receptor (IL 2R) termed 3C7 and 7D4, which bind to different epitopes on the murine IL 2R, to develop an ELISA to measure soluble murine IL 2R. Surprisingly, stimulated murine spleen cells not only expressed cell-associated IL 2R, but also produced a considerable level of cellfree IL 2R in the culture supernatant fluid. To assess the fine specificity of this response, myoglobin-immune murine T cell clones were stimulated with appropriate or inappropriate antigen and syngeneic or allogeneic presenting cells. Proliferation, measured by [ 3 H] thymidine incorporation, and levels of soluble IL 2R were determined at day 4. The production of soluble IL2R displayed the same epitope fine specificity, genetic restriction, and antigen dose-response as the proliferative response. Indeed, in some cases there was sharper discrimination of epitope specificity and genetic restriction with the soluble IL 2R levels. There was also reproducible clone-to-clone variation in the amount of soluble receptor produced in response to antigen among 12 T cell clones and lines tested. In time course experiments, proliferation was greatest at day 3, whereas soluble IL 2R levels continued to rise in subsequent days. To the authors' knowledge, this is the first demonstration of release of secretion of soluble IL 2R by murine T cells, and the first demonstration of the fine specificity and genetic restriction of the induction of soluble IL 2R by specific antigen

The Genome-Wide Analysis of Carcinoembryonic Antigen Signaling by Colorectal Cancer Cells Using RNA Sequencing.

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Olga Bajenova

Full Text Available Сarcinoembryonic antigen (CEA, CEACAM5, CD66 is a promoter of metastasis in epithelial cancers that is widely used as a prognostic clinical marker of metastasis. The aim of this study is to identify the network of genes that are associated with CEA-induced colorectal cancer liver metastasis. We compared the genome-wide transcriptomic profiles of CEA positive (MIP101 clone 8 and CEA negative (MIP 101 colorectal cancer cell lines with different metastatic potential in vivo. The CEA-producing cells displayed quantitative changes in the level of expression for 100 genes (over-expressed or down-regulated. They were confirmed by quantitative RT-PCR. The KEGG pathway analysis identified 4 significantly enriched pathways: cytokine-cytokine receptor interaction, MAPK signaling pathway, TGF-beta signaling pathway and pyrimidine metabolism. Our results suggest that CEA production by colorectal cancer cells triggers colorectal cancer progression by inducing the epithelial- mesenchymal transition, increasing tumor cell invasiveness into the surrounding tissues and suppressing stress and apoptotic signaling. The novel gene expression distinctions establish the relationships between the existing cancer markers and implicate new potential biomarkers for colorectal cancer hepatic metastasis.

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

International Nuclear Information System (INIS)

Rivera, Julie A.; McGuire, Travis C.

2005-01-01

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 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 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

Chimeric Antigen Receptor-Engineered T Cells in Tumor Immunotherapy: From Bench to Beside

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Peng WANG

2017-06-01

Full Text Available Chimeric antigen receptor-engineered T cells (CAR-T cells, a classification of cultured T cells after modification of gene engineering technology, can recognize specific tumor antigens in a major histocompatibility complex (MHC-independent manner, consequently leading to the activation of antitumor function. The recent studies have confirmed that a variety of tumor-associated antigens (TAAs can act as target antigens for CAR-T cells. Nowadays, CAR T-cell therapy, one of the most potential tumor immunotherapies, has made great breakthroughs in hematological malignancies and promising outcomes in solid tumors. In this article, the biological characteristics and antitumor mechanism of CAR-T cells, and their application in tumor treatment were mainly reviewed.

Antigen-Specific Polyclonal Cytotoxic T Lymphocytes Induced by Fusions of Dendritic Cells and Tumor Cells

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Shigeo Koido

2010-01-01

Full Text Available The aim of cancer vaccines is induction of tumor-specific cytotoxic T lymphocytes (CTLs that can reduce the tumor mass. Dendritic cells (DCs are potent antigen-presenting cells and play a central role in the initiation and regulation of primary immune responses. Thus, DCs-based vaccination represents a potentially powerful strategy for induction of antigen-specific CTLs. Fusions of DCs and whole tumor cells represent an alternative approach to deliver, process, and subsequently present a broad spectrum of antigens, including those known and unidentified, in the context of costimulatory molecules. Once DCs/tumor fusions have been infused back into patient, they migrate to secondary lymphoid organs, where the generation of antigen-specific polyclonal CTL responses occurs. We will discuss perspectives for future development of DCs/tumor fusions for CTL induction.

Viral sequestration of antigen subverts cross presentation to CD8(+ T cells.

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Eric F Tewalt

2009-05-01

Full Text Available Virus-specific CD8(+ T cells (T(CD8+ 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 T(CD8+. 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 T(CD8+ 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 T(CD8+ response and a potential replicative advantage for the virus. Such mechanisms of viral modulation of antigen presentation

Pooled protein immunization for identification of cell surface antigens in Streptococcus sanguinis.

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Xiuchun Ge

2010-07-01

Full Text Available Available bacterial genomes provide opportunities for screening vaccines by reverse vaccinology. Efficient identification of surface antigens is required to reduce time and animal cost in this technology. We developed an approach to identify surface antigens rapidly in Streptococcus sanguinis, a common infective endocarditis causative species.We applied bioinformatics for antigen prediction and pooled antigens for immunization. Forty-seven surface-exposed proteins including 28 lipoproteins and 19 cell wall-anchored proteins were chosen based on computer algorithms and comparative genomic analyses. Eight proteins among these candidates and 2 other proteins were pooled together to immunize rabbits. The antiserum reacted strongly with each protein and with S. sanguinis whole cells. Affinity chromatography was used to purify the antibodies to 9 of the antigen pool components. Competitive ELISA and FACS results indicated that these 9 proteins were exposed on S. sanguinis cell surfaces. The purified antibodies had demonstrable opsonic activity.The results indicate that immunization with pooled proteins, in combination with affinity purification, and comprehensive immunological assays may facilitate cell surface antigen identification to combat infectious diseases.

Pooled protein immunization for identification of cell surface antigens in Streptococcus sanguinis.

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Ge, Xiuchun; Kitten, Todd; Munro, Cindy L; Conrad, Daniel H; Xu, Ping

2010-07-26

Available bacterial genomes provide opportunities for screening vaccines by reverse vaccinology. Efficient identification of surface antigens is required to reduce time and animal cost in this technology. We developed an approach to identify surface antigens rapidly in Streptococcus sanguinis, a common infective endocarditis causative species. We applied bioinformatics for antigen prediction and pooled antigens for immunization. Forty-seven surface-exposed proteins including 28 lipoproteins and 19 cell wall-anchored proteins were chosen based on computer algorithms and comparative genomic analyses. Eight proteins among these candidates and 2 other proteins were pooled together to immunize rabbits. The antiserum reacted strongly with each protein and with S. sanguinis whole cells. Affinity chromatography was used to purify the antibodies to 9 of the antigen pool components. Competitive ELISA and FACS results indicated that these 9 proteins were exposed on S. sanguinis cell surfaces. The purified antibodies had demonstrable opsonic activity. The results indicate that immunization with pooled proteins, in combination with affinity purification, and comprehensive immunological assays may facilitate cell surface antigen identification to combat infectious diseases.

Down-regulation of Rab5 decreases characteristics associated with maintenance of cell transformation

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Silva, Patricio; Soto, Nicolás; Díaz, Jorge; Mendoza, Pablo; Díaz, Natalia; Quest, Andrew F.G.; Torres, Vicente A.

2015-01-01

The early endosomal protein Rab5 is highly expressed in tumor samples, although a causal relationship between Rab5 expression and cell transformation has not been established. Here, we report the functional effects of targeting endogenous Rab5 with specific shRNA sequences in different tumor cell lines. Rab5 down-regulation in B16-F10 cells decreased tumor formation by subcutaneous injection into C57/BL6 mice. Accordingly, Rab5 targeting in B16-F10 and A549, but not MDA-MB-231 cells was followed by decreased cell proliferation, increased apoptosis and decreased anchorage-independent growth. These findings suggest that Rab5 expression is required to maintain characteristics associated with cell transformation. - Highlights: • Rab5 is important to the maintenance of cell transformation characteristics. • Down-regulation of Rab5 decreases cell proliferation and increases apoptosis in different cancer cells. • Rab5 is required for anchorage-independent growth and tumorigenicity in-vivo

Lym-1 Chimeric Antigen Receptor T Cells Exhibit Potent Anti-Tumor Effects against B-Cell Lymphoma

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Long Zheng

2017-12-01

Full Text Available T cells expressing chimeric antigen receptors (CARs recognizing CD19 epitopes have produced remarkable anti-tumor effects in patients with B-cell malignancies. However, cancer cells lacking recognized epitopes can emerge, leading to relapse and death. Thus, CAR T cells targeting different epitopes on different antigens could improve immunotherapy. The Lym-1 antibody targets a conformational epitope of Human Leukocyte Antigen-antigen D Related (HLA-DR on the surface of human B-cell lymphomas. Lym-1 CAR T cells were thus generated for evaluation of cytotoxic activity towards lymphoma cells in vitro and in vivo. Human T cells from healthy donors were transduced to express a Lym-1 CAR, and assessed for epitope-driven function in culture and towards Raji xenografts in NOD-scidIL2Rgammanull (NSG mice. Lym-1 CAR T cells exhibited epitope-driven activation and lytic function against human B-cell lymphoma cell lines in culture and mediated complete regression of Raji/Luciferase-Green fluorescent protein (Raji/Luc-GFP in NSG mice with similar or better reactivity than CD19 CAR T cells. Lym-1 CAR transduction of T cells is a promising immunotherapy for patients with Lym-1 epitope positive B-cell malignancies.

Isolation and characterization of NIH 3T3 cells expressing polyomavirus small T antigen

International Nuclear Information System (INIS)

Noda, T.; Satake, M.; Robins, T.; Ito, Y.

1986-01-01

The polyomavirus small T-antigen gene, together with the polyomavirus promoter, was inserted into retrovirus vector pGV16 which contains the Moloney sarcoma virus long terminal repeat and neomycin resistance gene driven by the simian virus 40 promoter. This expression vector, pGVST, was packaged into retrovirus particles by transfection of PSI2 cells which harbor packaging-defective murine retrovirus genome. NIH 3T3 cells were infected by this replication-defective retrovirus containing pGVST. Of the 15 G418-resistant cell clones, 8 express small T antigen at various levels as revealed by immunoprecipitation. A cellular protein with an apparent molecular weight of about 32,000 coprecipitates with small T antigen. Immunofluorescent staining shows that small T antigen is mainly present in the nuclei. Morphologically, cells expressing small T antigen are indistinguishable from parental NIH 3T3 cells and have a microfilament pattern similar to that in parental NIH 3T3 cells. Cells expressing small T antigen form a flat monolayer but continue to grow beyond the saturation density observed for parental NIH 3T3 cells and eventually come off the culture plate as a result of overconfluency. There is some correlation between the level of expression of small T antigen and the growth rate of the cells. Small T-antigen-expressing cells form small colonies in soft agar. However, the proportion of cells which form these small colonies is rather small. A clone of these cells tested did not form tumors in nude mice within 3 months after inoculation of 10 6 cells per animal. Thus, present studies establish that the small T antigen of polyomavirus is a second nucleus-localized transforming gene product of the virus (the first one being large T antigen) and by itself has a function which is to stimulate the growth of NIH 3T3 cells beyond their saturation density in monolayer culture

A novel dendritic cell-based direct ex vivo assay for detection and enumeration of circulating antigen-specific human T cells.

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Carrio, Roberto; Zhang, Ge; Drake, Donald R; Schanen, Brian C

2018-05-07

Although a variety of assays have been used to examine T cell responses in vitro, standardized ex vivo detection of antigen-specific CD4 + T cells from human circulatory PBMCs remains constrained by low-dimensional characterization outputs and the need for polyclonal, mitogen-induced expansion methods to generate detectable response signals. To overcome these limitations, we developed a novel methodology utilizing antigen-pulsed autologous human dendritic target cells in a rapid and sensitive assay to accurately enumerate antigen-specific CD4 + T cell precursor frequency by multiparametric flow cytometry. With this approach, we demonstrate the ability to reproducibly quantitate poly-functional T cell responses following both primary and recall antigenic stimulation. Furthermore, this approach enables more comprehensive phenotypic profiling of circulating antigen-specific CD4 + T cells, providing valuable insights into the pre-existing polarization of antigen-specific T cells in humans. Combined, this approach permits sensitive and detailed ex vivo detection of antigen-specific CD4 + T cells delivering an important tool for advancing vaccine, immune-oncology and other therapeutic studies.

TCR down-regulation controls virus-specific CD8+ T cell responses

DEFF Research Database (Denmark)

Bonefeld, Charlotte Menné; Haks, Mariëlle; Nielsen, Bodil

2008-01-01

in mice with a mutated CD3gamma di-leucine-based motif. The CD3gamma mutation did not impair early TCR signaling, nor did it compromise recruitment or proliferation of virus-specific T cells, but it increased the apoptosis rate of the activated T cells by increasing down-regulation of the antiapoptotic...

Kaposi's sarcoma-associated herpesvirus latency-associated nuclear antigen prolongs the life span of primary human umbilical vein endothelial cells.

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Watanabe, Takahiro; Sugaya, Makoto; Atkins, April M; Aquilino, Elisabeth A; Yang, Aparche; Borris, Debra L; Brady, John; Blauvelt, Andrew

2003-06-01

Tumor spindle cells in all clinical types of Kaposi's sarcoma (KS) are infected with Kaposi's sarcoma-associated herpesvirus (KSHV). Although KSHV contains more than 80 genes, only a few are expressed in tumor spindle cells, including latency-associated nuclear antigen (LANA) and k-cyclin (kCYC). To assess the oncogenic potential of LANA and kCYC, primary human umbilical vein endothelial cells (HUVEC) and murine NIH 3T3 cells were stably transduced by using recombinant retroviruses expressing these genes or the known viral oncogene simian virus 40 large T antigen (LTAg). Interestingly, LANA-transduced HUVEC proliferated faster and demonstrated a greatly prolonged life span (mean +/- standard deviation, 38.3 +/- 11.0 passages) than untransduced cells and vector-transduced cells (<20 passages). By contrast, kCYC-transduced HUVEC did not proliferate faster or live longer than control cells. LANA- and kCYC-transduced HUVEC, but not LTAg-transduced HUVEC, retained the ability to form normal vessel-like structures in an in vitro model of angiogenesis. In cellular assays of transformation, LANA- and kCYC-transduced NIH 3T3 cells demonstrated minimal or no anchorage-independent growth in soft agar and no tumorigenicity when injected into nude mice, unlike LTAg-transduced NIH 3T3 cells. Lastly, gene expression profiling revealed down-regulation, or silencing, of a number of genes within LANA-transduced HUVEC. Taken together, these results suggest that KSHV LANA is capable of inducing prolonged life span, but not transformation, in primary human cells. These findings may explain why LANA-expressing spindle cells proliferate within KS tumors, yet most often do not demonstrate biologic characteristics of transformation or true malignant conversion.

Invariant NKT cells are required for airway inflammation induced by environmental antigens.

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Wingender, Gerhard; Rogers, Paul; Batzer, Glenda; Lee, Myung Steve; Bai, Dong; Pei, Bo; Khurana, Archana; Kronenberg, Mitchell; Horner, Anthony A

2011-06-06

Invariant NKT cells (iNKT cells) are a unique subset of T lymphocytes that rapidly carry out effector functions. In this study, we report that a majority of sterile house dust extracts (HDEs) tested contained antigens capable of activating mouse and human iNKT cells. HDEs had adjuvant-like properties in an ovalbumin (OVA)-induced asthma model, which were dependent on Vα14i NKT cells, as vaccinated animals deficient for iNKT cells displayed significantly attenuated immune responses and airway inflammation. Furthermore, the administration of HDEs together with OVA mutually augmented the synthesis of cytokines by Vα14i NKT cells and by conventional CD4(+) T cells in the lung, demonstrating a profound immune response synergy for both Th2 cytokines and IL-17A. These data demonstrate that iNKT cell antigens are far more widely dispersed in the environment than previously anticipated. Furthermore, as the antigenic activity in different houses varied greatly, they further suggest that iNKT cell responses to ambient antigens, particular to certain environments, might promote sensitization to conventional respiratory allergens.

A critical examination of the numerology of antigen-binding cells: evidence for multiple receptor specificities on single cells.

Science.gov (United States)

Miller, A

1977-01-01

The data available from other laboratories as well as our own on the frequency of cells recognizing major histocompatibility antigens or conventional protein and hapten antigens is critically evaluated. The frequency of specific binding for a large number of antigens is sufficiently high to support the idea that at least part of the antigen-binding cell population must have multiple specificities. Our results suggest that these multiple specific cells result from single cells synthesizing and displaying as many as 50-100 species of receptor, each at a frequency of 10(4) per cell. A model involving gene expansion of constant-region genes is suggested and some auxilliary evidence consistent with such C-gene expansion is presented.

Axotomy induces MHC class I antigen expression on rat nerve cells

DEFF Research Database (Denmark)

Maehlen, J; Schröder, H D; Klareskog, L

1988-01-01

Immunomorphological staining demonstrates that class I major histocompatibility complex (MHC)-coded antigen expression can be selectively induced on otherwise class I-negative rat nerve cells by peripheral axotomy. Induction of class I as well as class II antigen expression was simultaneously seen...... on non-neural cells in the immediate vicinity of the injured nerve cells. As nerve regeneration after axotomy includes growth of new nerve cell processes and formation of new nerve cell contacts, the present findings raise the question of a role for MHC-coded molecules in cell-cell interactions during...... nerve cell growth....

Immunoregulatory adherent cells in human tuberculosis: radiation-sensitive antigen-specific suppression by monocytes

Energy Technology Data Exchange (ETDEWEB)

Kleinhenz, M.E.; Ellner, J.J.

1985-07-01

In human tuberculosis, adherent mononuclear cells (AMC) selectively depress in vitro responses to the mycobacterial antigen tuberculin purified protein derivative (PPD). The phenotype of this antigen-specific adherent suppressor cell was characterized by examining the functional activity of adherent cells after selective depletion of sheep erythrocyte-rosetting T cells or OKM1-reactive monocytes. Adherent cell suppression was studied in the (/sup 3/H)thymidine-incorporation microculture assay by using T cells rigorously depleted of T cells with surface receptors for the Fc portion of IgG (T gamma cells) as antigen-responsive cells. PPD-induced (/sup 3/H)thymidine incorporation by these non gamma T cells was uniformly reduced (mean, 42% +/- 10% (SD)) when autologous AMC were added to non gamma T cells at a ratio of 1:2. Antigen-specific suppression by AMC was not altered by depletion of sheep erythrocyte-rosetting T cells or treatment with indomethacin. However, AMC treated with OKM1 and complement or gamma irradiation (1,500 rads) no longer suppressed tuberculin responses in vitro. These studies identify the antigen-specific adherent suppressor cell in tuberculosis as an OKM1-reactive, non-erythrocyte-rosetting monocyte. The radiosensitivity of this monocyte immunoregulatory function may facilitate its further definition.

Immunoregulatory adherent cells in human tuberculosis: radiation-sensitive antigen-specific suppression by monocytes

International Nuclear Information System (INIS)

Kleinhenz, M.E.; Ellner, J.J.

1985-01-01

In human tuberculosis, adherent mononuclear cells (AMC) selectively depress in vitro responses to the mycobacterial antigen tuberculin purified protein derivative (PPD). The phenotype of this antigen-specific adherent suppressor cell was characterized by examining the functional activity of adherent cells after selective depletion of sheep erythrocyte-rosetting T cells or OKM1-reactive monocytes. Adherent cell suppression was studied in the [ 3 H]thymidine-incorporation microculture assay by using T cells rigorously depleted of T cells with surface receptors for the Fc portion of IgG (T gamma cells) as antigen-responsive cells. PPD-induced [ 3 H]thymidine incorporation by these non gamma T cells was uniformly reduced (mean, 42% +/- 10% [SD]) when autologous AMC were added to non gamma T cells at a ratio of 1:2. Antigen-specific suppression by AMC was not altered by depletion of sheep erythrocyte-rosetting T cells or treatment with indomethacin. However, AMC treated with OKM1 and complement or gamma irradiation (1,500 rads) no longer suppressed tuberculin responses in vitro. These studies identify the antigen-specific adherent suppressor cell in tuberculosis as an OKM1-reactive, non-erythrocyte-rosetting monocyte. The radiosensitivity of this monocyte immunoregulatory function may facilitate its further definition

Chimeric antigen receptor T cells: a novel therapy for solid tumors

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Shengnan Yu

2017-03-01

Full Text Available Abstract The chimeric antigen receptor T (CAR-T cell therapy is a newly developed adoptive antitumor treatment. Theoretically, CAR-T cells can specifically localize and eliminate tumor cells by interacting with the tumor-associated antigens (TAAs expressing on tumor cell surface. Current studies demonstrated that various TAAs could act as target antigens for CAR-T cells, for instance, the type III variant epidermal growth factor receptor (EGFRvIII was considered as an ideal target for its aberrant expression on the cell surface of several tumor types. CAR-T cell therapy has achieved gratifying breakthrough in hematological malignancies and promising outcome in solid tumor as showed in various clinical trials. The third generation of CAR-T demonstrates increased antitumor cytotoxicity and persistence through modification of CAR structure. In this review, we summarized the preclinical and clinical progress of CAR-T cells targeting EGFR, human epidermal growth factor receptor 2 (HER2, and mesothelin (MSLN, as well as the challenges for CAR-T cell therapy.

Simultaneous targeting of prostate stem cell antigen and prostate-specific membrane antigen improves the killing of prostate cancer cells using a novel modular T cell-retargeting system.

Science.gov (United States)

Arndt, Claudia; Feldmann, Anja; Koristka, Stefanie; Cartellieri, Marc; Dimmel, Maria; Ehninger, Armin; Ehninger, Gerhard; Bachmann, Michael

2014-09-01

Recently, we described a novel modular platform technology in which T cell-recruitment and tumor-targeting domains of conventional bispecific antibodies are split to independent components, a universal effector module (EM) and replaceable monospecific/monovalent target modules (TMs) that form highly efficient T cell-retargeting complexes. Theoretically, our unique strategy should allow us to simultaneously retarget T cells to different tumor antigens by combining the EM with two or more different monovalent/monospecific TMs or even with bivalent/bispecific TMs, thereby overcoming limitations of a monospecific treatment such as the selection of target-negative tumor escape variants. In order to advance our recently introduced prostate stem cell antigen (PSCA)-specific modular system for a dual-targeting of prostate cancer cells, two additional TMs were constructed: a monovalent/monospecific TM directed against the prostate-specific membrane antigen (PSMA) and a bivalent/bispecific TM (bsTM) with specificity for PSMA and PSCA. The functionality of the novel dual-targeting strategies was analyzed by performing T cell activation and chromium release assays. Similar to the PSCA-specific modular system, the novel PSMA-specific modular system mediates an efficient target-dependent and -specific tumor cell lysis at low E:T ratios and picomolar Ab concentrations. Moreover, by combination of the EM with either the bispecific TM directed to PSMA and PSCA or both monospecifc TMs directed to either PSCA or PSMA, dual-specific targeting complexes were formed which allowed us to kill potential escape variants expressing only one or the other target antigen. Overall, the novel modular system represents a promising tool for multiple tumor targeting. © 2014 Wiley Periodicals, Inc.

The Missing Link in Epstein-Barr Virus Immune Evasion: the BDLF3 Gene Induces Ubiquitination and Downregulation of Major Histocompatibility Complex Class I (MHC-I) and MHC-II.

Science.gov (United States)

Quinn, Laura L; Williams, Luke R; White, Claire; Forrest, Calum; Zuo, Jianmin; Rowe, Martin

2016-01-01

The ability of Epstein-Barr virus (EBV) to spread and persist in human populations relies on a balance between host immune responses and EBV immune evasion. CD8(+) cells specific for EBV late lytic cycle antigens show poor recognition of target cells compared to immediate early and early antigen-specific CD8(+) cells. This phenomenon is due in part to the early EBV protein BILF1, whose immunosuppressive activity increases with lytic cycle progression. However, published data suggest the existence of a hitherto unidentified immune evasion protein further enhancing protection against late EBV antigen-specific CD8(+) cells. We have now identified the late lytic BDLF3 gene as the missing link accounting for efficient evasion during the late lytic cycle. Interestingly, BDLF3 also contributes to evasion of CD4(+) cell responses to EBV. We report that BDLF3 downregulates expression of surface major histocompatibility complex (MHC) class I and class II molecules in the absence of any effect upon other surface molecules screened, including CD54 (ICAM-1) and CD71 (transferrin receptor). BDLF3 both enhanced internalization of surface MHC molecules and reduced the rate of their appearance at the cell surface. The reduced expression of surface MHC molecules correlated with functional protection against CD8(+) and CD4(+) T cell recognition. The molecular mechanism was identified as BDLF3-induced ubiquitination of MHC molecules and their subsequent downregulation in a proteasome-dependent manner. Immune evasion is a necessary feature of viruses that establish lifelong persistent infections in the face of strong immune responses. EBV is an important human pathogen whose immune evasion mechanisms are only partly understood. Of the EBV immune evasion mechanisms identified to date, none could explain why CD8(+) T cell responses to late lytic cycle genes are so infrequent and, when present, recognize lytically infected target cells so poorly relative to CD8(+) T cells specific for

Cancer antigens are expressed in a carcinogen-transformed Bloom syndrome B-lymphoblastoid cell line

International Nuclear Information System (INIS)

Shiraishi, Yukimasa; Soma, Hiroaki

1988-01-01

The authors have cloned malignant cells carrying specific antigens associated with ovarian cancer (OVC) and malignant lymphoma (ML) from BS-SHI-4M cells, a line derived from a 1-methyl-3-nitro-1-nitrosoguanidine-treated B-lymphoblastoid cell line isolated from a patient with Bloom syndrome. Since BS-SHI-4M cells react with sera from various individual cancer patients at relatively low frequencies (2-9%), as detected by an indirect immunofluorescence technique, cell clones that specifically react with sera from patients with OVC and ML were separated by the panning method in which polystyrene dishes were coated with sera from OVC and ML patients and cells with the corresponding antigens bound to the dishes. Subsequent cloning by limiting dilution provided cell clones highly enriched for OVC- and ML-associated antigens. Karyotype analyses revealed that cell clones with OVC and ML antigens had common marker chromosomes. Interestingly, in cell clones with a strong OVC antigen response, the distal part of the Y chromosome (Yq11) was missing in 100% of the cells. Therefore the cell line BS-SHI-4M appears to be a reservoir of cell clones each of which carries a specific tumor antigen and thus provides a potential tool for rapid serological diagnosis of cancer

Docking of B-cell epitope antigen to specific hepatitis B antibody

Indian Academy of Sciences (India)

The interaction of pres1 region of hepatitis B virus B-cell epitope antigen with specific hepatitis B neutralizing monoclonal antibody was examined by docking study. We modelled the 3D complex structure of B-cell epitope antigen residues CTTPAQGNSMFPSCCCTKPTDGNCY by homology modelling and docked it with the ...

Classical dendritic cells are required for dietary antigen-mediated peripheral regulatory T cell and tolerance induction

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Esterházy, Daria; Loschko, Jakob; London, Mariya; Jove, Veronica; Oliveira, Thiago Y.; Mucida, Daniel

2016-01-01

Oral tolerance prevents pathological inflammatory responses towards innocuous foreign antigens via peripheral regulatory T cells (pTreg cells). However, whether a particular subset of antigen-presenting cells (APCs) is required during dietary antigen exposure to instruct naïve CD4+ T cells to differentiate into pTreg cells has not been defined. Using myeloid lineage-specific APC depletion in mice, we found that monocyte-derived APCs are dispensable, while classical dendritic cells (cDCs) are critical for pTreg cell induction and oral tolerance. CD11b− cDCs from the gut-draining lymph nodes efficiently induced pTreg cells, and conversely, loss of IRF8-dependent CD11b− cDCs impaired their polarization, although oral tolerance remained intact. These data reveal the hierarchy of cDC subsets in pTreg cell induction and their redundancy during oral tolerance development. PMID:27019226

Large, but not small, antigens require time- and temperature-dependent processing in accessory cells before they can be recognized by T cells

DEFF Research Database (Denmark)

Buus, S; Werdelin, O

1986-01-01

We have studied if antigens of different size and structure all require processing in antigen-presenting cells of guinea-pigs before they can be recognized by T cells. The method of mild paraformaldehyde fixation was used to stop antigen-processing in the antigen-presenting cells. As a measure...... of antigen presentation we used the proliferative response of appropriately primed T cells during a co-culture with the paraformaldehyde-fixed and antigen-exposed presenting cells. We demonstrate that the large synthetic polypeptide antigen, dinitrophenyl-poly-L-lysine, requires processing. After an initial......-dependent and consequently energy-requiring. Processing is strongly inhibited by the lysosomotrophic drug, chloroquine, suggesting a lysosomal involvement in antigen processing. The existence of a minor, non-lysosomal pathway is suggested, since small amounts of antigen were processed even at 10 degrees C, at which...

Challenges and prospects of chimeric antigen receptor T cell therapy in solid tumors.

Science.gov (United States)

Jindal, Vishal; Arora, Ena; Gupta, Sorab

2018-05-05

Chimeric antigen receptor (CAR) T cell therapy is a novel and innovative immunotherapy. CAR-T cells are genetically engineered T cells, carrying MHC independent specific antigen receptor and co-stimulatory molecule which can activate an immune response to a cancer specific antigen. This therapy showed great results in hematological malignancies but were unable to prove their worth in solid tumors. Likely reasons for their failure are lack of antigens, poor trafficking, and hostile tumor microenvironment. Excessive amount of research is going on to improve the efficacy of CAR T cell therapy in solid tumors. In this article, we will discuss the challenges faced in improving the outcome of CAR T cell therapy in solid tumors and various strategies adopted to curb them.

Mycobacterium leprae downregulates the expression of PHEX in Schwann cells and osteoblasts

Directory of Open Access Journals (Sweden)

Sandra R Boiça Silva

2010-08-01

Full Text Available Neuropathy and bone deformities, lifelong sequelae of leprosy that persist after treatment, result in significant impairment to patients and compromise their social rehabilitation. Phosphate-regulating gene with homologies to endopeptidase on the X chromosome (PHEX is a Zn-metalloendopeptidase, which is abundantly expressed in osteoblasts and many other cell types, such as Schwann cells, and has been implicated in phosphate metabolism and X-linked rickets. Here, we demonstrate that Mycobacterium leprae stimulation downregulates PHEX transcription and protein expression in a human schwannoma cell line (ST88-14 and human osteoblast lineage. Modulation of PHEX expression was observed to a lesser extent in cells stimulated with other species of mycobacteria, but was not observed in cultures treated with latex beads or with the facultative intracellular bacterium Salmonella typhimurium. Direct downregulation of PHEX by M. leprae could be involved in the bone resorption observed in leprosy patients. This is the first report to describe PHEX modulation by an infectious agent.

Down-regulation of endothelin binding sites in rat vascular smooth muscle cells

International Nuclear Information System (INIS)

Roubert, P.; Gillard, V.; Plas, P.; Chabrier, P.E.; Braquet, P.

1990-01-01

In cultured rat aortic smooth muscle cells, [ 125 I]endothelin (ET-1) bound to an apparent single class of high affinity recognition sites with a dissociation constant of 1.84 +/- 0.29 nmol/L and a maximum binding of 62 +/- 10.5 fmol/10(6) cells. The binding was not affected by calcium antagonists or vasoactive substances, including angiotensin II, arginine vasopressin, atrial natriuretic factor and bradykinin. Exposure of the cells to ET-1 (0.01 nmol/L to 10 nmol/L) resulted in an apparent dose-dependent reduction of the number of endothelin binding sites with no significant modification of its binding affinity. The time course of the down-regulation of ET-1 binding sites showed that this effect was present after 30 min incubation and persisted after 18 h. This indicates that down-regulation of ET-1 binding sites can modulate the activity of ET-1 and suggests a rapid internalization of ET-1 in vascular cells

Precision cancer immunotherapy: optimizing dendritic cell-based strategies to induce tumor antigen-specific T-cell responses against individual patient tumors.

Science.gov (United States)

Osada, Takuya; Nagaoka, Koji; Takahara, Masashi; Yang, Xiao Yi; Liu, Cong-Xiao; Guo, Hongtao; Roy Choudhury, Kingshuk; Hobeika, Amy; Hartman, Zachary; Morse, Michael A; Lyerly, H Kim

2015-05-01

Most dendritic cell (DC)-based vaccines have loaded the DC with defined antigens, but loading with autologos tumor-derived antigens would generate DCs that activate personalized tumor-specific T-cell responses. We hypothesized that DC matured with an optimized combination of reagents and loaded with tumor-derived antigens using a clinically feasible electroporation strategy would induce potent antitumor immunity. We first studied the effects on DC maturation and antigen presentation of the addition of picibanil (OK432) to a combination of zoledronic acid, tumor necrosis factor-α, and prostaglandin E2. Using DC matured with the optimized combination, we tested 2 clinically feasible sources of autologous antigen for electroloading, total tumor mRNA or total tumor lysate, to determine which stimulated more potent antigen-specific T cells in vitro and activated more potent antitumor immunity in vivo. The combination of tumor necrosis factor-α/prostaglandin E2/zoledronic acid/OK432 generated DC with high expression of maturation markers and antigen-specific T-cell stimulatory function in vitro. Mature DC electroloaded with tumor-derived mRNA [mRNA electroporated dendritic cell (EPDC)] induced greater expansion of antigen-specific T cells in vitro than DC electroloaded with tumor lysate (lysate EPDC). In a therapeutic model of MC38-carcinoembryonic antigen colon cancer-bearing mice, vaccination with mRNA EPDC induced the most efficient anti-carcinoembryonic antigen cellular immune response, which significantly suppressed tumor growth. In conclusion, mature DC electroloaded with tumor-derived mRNA are a potent cancer vaccine, especially useful when specific tumor antigens for vaccination have not been identified, allowing autologous tumor, and if unavailable, allogeneic cell lines to be used as an unbiased source of antigen. Our data support clinical testing of this strategy.

Downregulation of tropomyosin-1 in squamous cell carcinoma of esophagus, the role of Ras signaling and methylation.

Science.gov (United States)

Zare, Maryam; Jazii, Ferdous Rastgar; Soheili, Zahra-Soheila; Moghanibashi, Mohamad-Mehdi

2012-10-01

Tropomyosins (TMs) are a family of cytoskeletal proteins that bind to and stabilize actin microfilaments. Non-muscle cells express multiple isoforms of TMs including three high molecular weight (HMW) isoforms: TM1, TM2, and TM3. While reports have indicated downregulation of TMs in transformed cells and several human cancers, nevertheless, little is known about the underlying mechanism of TMs suppression. In present study the expression of HMW TMs was investigated in squamous cell carcinoma of esophagus (SCCE), relative to primary cell cultures of normal esophagus by western blotting and real-time RT-PCR. Our results showed that TM1, TM2, and TM3 were significantly downregulated in cell line of SCCE. Moreover, mRNA level of TPM1 and TPM2 were markedly decreased by 93% and 96%, in tumor cell line relative to esophagus normal epithelial cells. Therefore, downregulation of TMs could play an important role in tumorigenesis of esophageal cancer. To asses the mechanism of TM downregulation in esophageal cancer, the role of Ras dependent signaling and promoter hypermethylation were investigated. We found that inhibition of two Ras effectory downstream pathways; MEK/ERK and PI3K/Akt leads to significant increased expression of TM1 protein and both TPM1 and TPM2 mRNAs. In addition, methyltransferase inhibition significantly upregulated TM1, suggesting the prominent contribution of promoter hypermethylation in TM1 downregulation in esophageal cancer. These data indicate that downregulation of HMW TMs occurs basically in SCCE and the activation of MEK/ERK and PI3K/Akt pathways as well as the epigenetic mechanism of promoter hypermethylation play important role in TM1 suppression in SCCE. Copyright © 2011 Wiley Periodicals, Inc.

Cancer Patient T Cells Genetically Targeted to Prostate-Specific Membrane Antigen Specifically Lyse Prostate Cancer Cells and Release Cytokines in Response to Prostate-Specific Membrane Antigen

Directory of Open Access Journals (Sweden)

Michael C. Gong

1999-06-01

Full Text Available The expression of immunoglobulin-based artificial receptors in normal T lymphocytes provides a means to target lymphocytes to cell surface antigens independently of major histocompatibility complex restriction. Such artificial receptors have been previously shown to confer antigen-specific tumoricidal properties in murine T cells. We constructed a novel ζ chain fusion receptor specific for prostate-specific membrane antigen (PSMA termed Pz-1. PSMA is a cell-surface glycoprotein expressed on prostate cancer cells and the neovascular endothelium of multiple carcinomas. We show that primary T cells harvested from five of five patients with different stages of prostate cancer and transduced with the Pz-1 receptor readily lyse prostate cancer cells. Having established a culture system using fibroblasts that express PSMA, we next show that T cells expressing the Pz-1 receptor release cytokines in response to cell-bound PSMA. Furthermore, we show that the cytokine release is greatly augmented by B7.1-mediated costimulation. Thus, our findings support the feasibility of adoptive cell therapy by using genetically engineered T cells in prostate cancer patients and suggest that both CD4+ and CD8+ T lymphocyte functions can be synergistically targeted against tumor cells.

Pros and Cons of Antigen-Presenting Cell Targeted Tumor Vaccines

Directory of Open Access Journals (Sweden)

Cleo Goyvaerts

2015-01-01

Full Text Available 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.

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

Directory of Open Access Journals (Sweden)

Gao J

2017-02-01

Full Text Available Jie Gao,1–3 Lukasz J Ochyl,1,3 Ellen Yang,4 James J Moon1,3,5 1Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, USA; 2Department of Pharmaceutical Sciences, School of Pharmacy, Second Military Medical University, Shanghai, People’s Republic of China; 3Biointerfaces Institute, 4Department of Chemistry, 5Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA Abstract: 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

Production of prostate-specific antigen by a breast cancer cell line, Sk-Br-3

International Nuclear Information System (INIS)

Kamali Sarvestani, E.; Ghaderi, A.

2002-01-01

Prostate-specific antigen is a 33-KDa serine protease that is produced predominantly by prostate epithelium. However, it has been shown that about 30-40% of female breast tumors produce prostate-specific antigen and its production is associated with the presence of estrogen and progesterone receptors. We have now developed a new tissue culture system to study prostate-specific antigen production in breast cancer and its association with prognostic factors such as progesterone receptor and c-erbB-2. For this purpose we investigated the ability of prostate-specific antigen production in five different cell lines, including two breast cancer cell lines, Sk-Br-3 and MDA-MB-453. The prostate-specific antigen in tissue culture supernatant and cytoplasm of the Sk-Br-3 cell line was detected by western blotting and immunoperoxidase, respectively. Furthermore, we found lower expression of c-erbB-2 in Sk-Br-3 than non-prostate-specific antigen producer breast cancer cell line, MDA-MB-453. Progesterone receptor was expressed by both prostate-specific antigen-positive and -negative cell lines and only the intensity of staining and the number of positive cells in Sk-Br-3 population was higher than MDA-MB-453. According to our findings prostate-specific antigen can be considered as a good prognostic factor in breast cancer and we suggest that these two cell lines are a good in vitro model to study the relationship of different breast cancer prognostic factors and their regulations

Down-regulation of lipoprotein lipase increases glucose uptake in L6 muscle cells

Energy Technology Data Exchange (ETDEWEB)

Lopez, Veronica; Saraff, Kumuda [Department of Chemistry and Biochemistry, California State University Northridge, Northridge, CA 91330-8262 (United States); Medh, Jheem D., E-mail: jheem.medh@csun.edu [Department of Chemistry and Biochemistry, California State University Northridge, Northridge, CA 91330-8262 (United States)

2009-11-06

Thiazolidinediones (TZDs) are synthetic hypoglycemic agents used to treat type 2 diabetes. TZDs target the peroxisome proliferator activated receptor-gamma (PPAR-{gamma}) and improve systemic insulin sensitivity. The contributions of specific tissues to TZD action, or the downstream effects of PPAR-{gamma} activation, are not very clear. We have used a rat skeletal muscle cell line (L6 cells) to demonstrate that TZDs directly target PPAR-{gamma} in muscle cells. TZD treatment resulted in a significant repression of lipoprotein lipase (LPL) expression in L6 cells. This repression correlated with an increase in glucose uptake. Down-regulation of LPL message and protein levels using siRNA resulted in a similar increase in insulin-dependent glucose uptake. Thus, LPL down-regulation improved insulin sensitivity independent of TZDs. This finding provides a novel method for the management of insulin resistance.

Downregulation of proapoptotic Bim augments IL-2-independent T-cell transformation by human T-cell leukemia virus type-1 Tax

International Nuclear Information System (INIS)

Higuchi, Masaya; Takahashi, Masahiko; Tanaka, Yuetsu; Fujii, Masahiro

2014-01-01

Human T-cell leukemia virus type 1 (HTLV-1), an etiological agent of adult T-cell leukemia, immortalizes and transforms primary human T cells in vitro in both an interleukin (IL)-2-dependent and IL-2-independent manner. Expression of the HTLV-1 oncoprotein Tax transforms the growth of the mouse T-cell line CTLL-2 from being IL-2-dependent to IL-2-independent. Withdrawal of IL-2 from normal activated T cells induces apoptosis, which is mediated through the inducible expression of several proapoptotic proteins, including Bim. In this study, we found that Tax protects IL-2-depleted T cells against Bim-induced apoptosis. Withdrawal of IL-2 from CTLL-2 cells induced a prominent increase in the level of Bim protein in CTLL-2 cells, but not in Tax-transformed CTLL-2 cells. This inhibition of Bim in Tax-transformed CTLL-2 cells was mediated by two mechanisms: downregulation of Bim mRNA and posttranscriptional reduction of Bim protein. Transient expression of Tax in CTLL-2 cells also inhibited IL-2 depletion–induced expression of Bim, however, this decrease in Bim protein expression was not due to downregulation of Bim mRNA, thus indicating that Bim mRNA downregulation in Tax-transformed CTLL-2 occurs only after long-term expression of Tax. Transient expression of Tax in CTLL-2 cells also induced Erk activation, however, this was not involved in the reduction of Bim protein. Knockdown of Bim expression in CTLL-2 cells augmented Tax-induced IL-2-independent transformation. HTLV-1 infection of human T cells also reduced their levels of Bim protein, and restoring Bim expression in HTLV-1-infected cells reduced their proliferation by inducing apoptosis. Taken together, these results indicate that Tax-induced downregulation of Bim in HTLV-1-infected T cells promotes their IL-2-independent growth, thereby supporting the persistence of HTLV-1 infection in vivo

Downregulation of proapoptotic Bim augments IL-2-independent T-cell transformation by human T-cell leukemia virus type-1 Tax.

Science.gov (United States)

Higuchi, Masaya; Takahashi, Masahiko; Tanaka, Yuetsu; Fujii, Masahiro

2014-12-01

Human T-cell leukemia virus type 1 (HTLV-1), an etiological agent of adult T-cell leukemia, immortalizes and transforms primary human T cells in vitro in both an interleukin (IL)-2-dependent and IL-2-independent manner. Expression of the HTLV-1 oncoprotein Tax transforms the growth of the mouse T-cell line CTLL-2 from being IL-2-dependent to IL-2-independent. Withdrawal of IL-2 from normal activated T cells induces apoptosis, which is mediated through the inducible expression of several proapoptotic proteins, including Bim. In this study, we found that Tax protects IL-2-depleted T cells against Bim-induced apoptosis. Withdrawal of IL-2 from CTLL-2 cells induced a prominent increase in the level of Bim protein in CTLL-2 cells, but not in Tax-transformed CTLL-2 cells. This inhibition of Bim in Tax-transformed CTLL-2 cells was mediated by two mechanisms: downregulation of Bim mRNA and posttranscriptional reduction of Bim protein. Transient expression of Tax in CTLL-2 cells also inhibited IL-2 depletion-induced expression of Bim, however, this decrease in Bim protein expression was not due to downregulation of Bim mRNA, thus indicating that Bim mRNA downregulation in Tax-transformed CTLL-2 occurs only after long-term expression of Tax. Transient expression of Tax in CTLL-2 cells also induced Erk activation, however, this was not involved in the reduction of Bim protein. Knockdown of Bim expression in CTLL-2 cells augmented Tax-induced IL-2-independent transformation. HTLV-1 infection of human T cells also reduced their levels of Bim protein, and restoring Bim expression in HTLV-1-infected cells reduced their proliferation by inducing apoptosis. Taken together, these results indicate that Tax-induced downregulation of Bim in HTLV-1-infected T cells promotes their IL-2-independent growth, thereby supporting the persistence of HTLV-1 infection in vivo. © 2014 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

CD8(+)NKT-like cells regulate the immune response by killing antigen-bearing DCs.

Science.gov (United States)

Wang, Chao; Liu, Xi; Li, Zhengyuan; Chai, Yijie; Jiang, Yunfeng; Wang, Qian; Ji, Yewei; Zhu, Zhongli; Wan, Ying; Yuan, Zhenglong; Chang, Zhijie; Zhang, Minghui

2015-09-15

CD1d-dependent NKT cells have been extensively studied; however, the function of CD8(+)NKT-like cells, which are CD1d-independent T cells with NK markers, remains unknown. Here, we report that CD1d-independent CD8(+)NKT-like cells, which express both T cell markers (TCRβ and CD3) and NK cell receptors (NK1.1, CD49b and NKG2D), are activated and significantly expanded in mice immunized with GFP-expressing dendritic cells. Distinct from CD1d-dependent NKT cells, CD8(+)NKT-like cells possess a diverse repertoire of TCRs and secrete high levels of IFN-gamma but not IL-4. CD8(+)NKT-like cell development is normal in CD1d(-/-) mice, which suggests that CD8(+)NKT-like cells undergo a unique development pathway that differs from iNKT cells. Further functional analyses show that CD8(+)NKT-like cells suppress T-cell responses through elimination of dendritic cells in an antigen-specific manner. Adoptive transfer of antigen-specific CD8(+)NKT-like cells into RIP-OVA mice prevented subsequent development of diabetes in the animals induced by activated OT-I CD8 T cells. Our study suggests that CD8(+)NKT-like cells can function as antigen-specific suppressive cells to regulate the immune response through killing antigen-bearing DCs. Antigen-specific down regulation may provide an active and precise method for constraining an excessive immune response and avoiding bypass suppression of necessary immune responses to other antigens.

CD8+NKT-like cells regulate the immune response by killing antigen-bearing DCs

Science.gov (United States)

Wang, Chao; Liu, Xi; Li, Zhengyuan; Chai, Yijie; Jiang, Yunfeng; Wang, Qian; Ji, Yewei; Zhu, Zhongli; Wan, Ying; Yuan, Zhenglong; Chang, Zhijie; Zhang, Minghui

2015-01-01

CD1d-dependent NKT cells have been extensively studied; however, the function of CD8+NKT-like cells, which are CD1d-independent T cells with NK markers, remains unknown. Here, we report that CD1d-independent CD8+NKT-like cells, which express both T cell markers (TCRβ and CD3) and NK cell receptors (NK1.1, CD49b and NKG2D), are activated and significantly expanded in mice immunized with GFP-expressing dendritic cells. Distinct from CD1d-dependent NKT cells, CD8+NKT-like cells possess a diverse repertoire of TCRs and secrete high levels of IFN-gamma but not IL-4. CD8+NKT-like cell development is normal in CD1d−/− mice, which suggests that CD8+NKT-like cells undergo a unique development pathway that differs from iNKT cells. Further functional analyses show that CD8+NKT-like cells suppress T-cell responses through elimination of dendritic cells in an antigen-specific manner. Adoptive transfer of antigen-specific CD8+NKT-like cells into RIP-OVA mice prevented subsequent development of diabetes in the animals induced by activated OT-I CD8 T cells. Our study suggests that CD8+NKT-like cells can function as antigen-specific suppressive cells to regulate the immune response through killing antigen-bearing DCs. Antigen-specific down regulation may provide an active and precise method for constraining an excessive immune response and avoiding bypass suppression of necessary immune responses to other antigens. PMID:26369936

Abscisic acid ameliorates experimental IBD by downregulating cellular adhesion molecule expression and suppressing immune cell infiltration.

Science.gov (United States)

Guri, Amir J; Hontecillas, Raquel; Bassaganya-Riera, Josep

2010-12-01

Abscisic acid (ABA) has shown effectiveness in ameliorating inflammation in obesity, diabetes and cardiovascular disease models. The objective of this study was to determine whether ABA prevents or ameliorates experimental inflammatory bowel disease (IBD). C57BL/6J mice were fed diets with or without ABA (100mg/kg) for 35 days prior to challenge with 2.5% dextran sodium sulfate (DSS). The severity of clinical disease was assessed daily. Colonic mucosal lesions were evaluated by histopathology, and cellular adhesion molecular and inflammatory markers were assayed by real-time quantitative PCR. Flow cytometry was used to quantify leukocyte populations in the blood, spleen, and mesenteric lymph nodes (MLN). The effect of ABA on cytotoxic T-lymphocyte antigen 4 (CTLA-4) expression in splenocytes was also investigated. ABA significantly ameliorated disease activity, colitis and reduced colonic leukocyte infiltration and inflammation. These improvements were associated with downregulation in vascular cell adhesion marker-1 (VCAM-1), E-selectin, and mucosal addressin adhesion marker-1 (MAdCAM-1) expression. ABA also increased CD4(+) and CD8(+) T-lymphocytes in blood and MLN and regulatory T cells in blood. In vitro, ABA increased CTLA-4 expression through a PPAR γ-dependent mechanism. We conclude that ABA ameliorates gut inflammation by modulating T cell distribution and adhesion molecule expression. Copyright © 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Adult T-cell leukemia-associated antigen (ATLA): detection of a glycoprotein in cell- and virus-free supernatant.

Science.gov (United States)

Yamamoto, N; Schneider, J; Hinuma, Y; Hunsmann, G

1982-01-01

A glycoprotein of an apparent molecular mass of 46,000, gp 46, was enriched by affinity chromatography from the virus- and cell-free culture medium of adult T-cell leukemia virus (ATLV) infected cells. gp 46 was specifically precipitated with sera from patients with adult T-cell leukemia associated antigen (ATLA). Thus, gp 46 is a novel component of the ATLA antigen complex.

Evidence against suppressor cell involvement in naturally acquired tolerance of a minor histocompatibility antigen

International Nuclear Information System (INIS)

Johnson, L.L.

1991-01-01

The hypothesis was investigated that suppressor cells may be responsible for maintenance of immunologic tolerance of a minor H3 antigen in mice that express the antigen naturally. Lymphoid cell populations from B6.C-H-24c (HW54) mice, a congenic-resistant strain histoincompatible with H-24b-expressing C57BL/6 (B6) mice only with respect to the H-24 locus, were examined in cell-transfer experiments to see if they contained naturally arising H-24c-specific suppressor cells. The H-24 antigen was chosen for these studies because, unlike most other minor and major histocompatibility (H) antigens, it is not detectable on mature lymphoid cells by any of several functional criteria. Thus transfer of HW54 lymphoid cells to B6 hosts could be done without the complication of inducing hyporesponsiveness de novo in the host, as occurs with other minor H antigens that are expressed on lymphocytes. B6 hosts were given HW54 skin grafts along with HW54 lymphoid cells to assess their tolerance of the H-24c-encoded antigen. The hosts were either (1) normal, nonimmune B6 mice; (2) B6 mice rendered immunodeficient by thymectomy and irradiation (TxB) and repopulated with H-24c-immune B6 lymphocytes; or (3) TxB B6 hosts repopulated with nonimmune B6 lymphocytes. In each case it was found that the additionally infused HW54 lymphoid cells did not suppress the ability of these hosts to reject HW54 skin grafts. In other words, HW54 lymphoid cells appear not to possess suppressive activity specific for the H-24c antigen that might maintain antigen-specific natural tolerance. Additional experiments were performed to determine whether HW54 lymphoid cells can inhibit the ability of sublethally irradiated B6 mice to regain the capacity to reject HW54 skin

Ligation of major histocompatibility complex class I antigens (MHC-I) prevents apoptosis induced by Fas or SAPK/JNK activation in T-lymphoma cells

DEFF Research Database (Denmark)

Lamberth, K; Claesson, M H

2001-01-01

Early apoptosis in Jurkat T-lymphoma cells was induced by agonistic anti-Fas Ab or by anisomycin which activates the stress kinases SAPK/JNK. Apoptosis was inhibited by ligation of major histocompatibility complex class I antigens (MHC-I). MHC-I ligation induced upregulation of the anti......-apoptotic Bcl-2 protein and stabilized the mitochondrial membrane potential (Deltapsim). MHC-I ligation also prevented downregulation of Bcl-2 and destabilization of Deltapsim induced by anti-Fas Ab treatment or anisomycin exposure. Studies on three different Jurkat cell mutants deficient for src p56(lck), ZAP......-70 kinase, or TCR/CD3 gamma-chain showed that the cells undergo apoptosis after Fas ligation. Anisomycin exposure induced apoptosis in the src p56(lck)-deficient cell line but not in the two other mutant cell lines. Simultaneous cross-linking of MHC-I and Fas ligation inhibited apoptosis in the ZAP...

Multinuclear giant cell formation is enhanced by down-regulation of Wnt signaling in gastric cancer cell line, AGS

International Nuclear Information System (INIS)

Kim, Shi-Mun; Kim, Rockki; Ryu, Jae-Hyun; Jho, Eek-Hoon; Song, Ki-Joon; Jang, Shyh-Ing; Kee, Sun-Ho

2005-01-01

AGS cells, which were derived from malignant gastric adenocarcinoma tissue, lack E-cadherin-mediated cell adhesion but have a high level of nuclear β-catenin, which suggests altered Wnt signal. In addition, approximately 5% of AGS cells form multinuclear giant cells in the routine culture conditions, while taxol treatment causes most AGS cells to become giant cells. The observation of reduced nuclear β-catenin levels in giant cells induced by taxol treatment prompted us to investigate the relationship between Wnt signaling and giant cell formation. After overnight serum starvation, the shape of AGS cells became flattened, and this morphological change was accompanied by decrease in Myc expression and an increase in the giant cell population. Lithium chloride treatment, which inhibits GSK3β activity, reversed these serum starvation effects, which suggests an inverse relationship between Wnt signaling and giant cell formation. Furthermore, the down-regulation of Wnt signaling caused by the over-expression of ICAT, E-cadherin, and Axin enhanced giant cell formation. Therefore, down-regulation of Wnt signaling may be related to giant cell formation, which is considered to be a survival mechanism against induced cell death

microRNA-188 is downregulated in oral squamous cell carcinoma and inhibits proliferation and invasion by targeting SIX1.

Science.gov (United States)

Wang, Lili; Liu, Hongchen

2016-03-01

microRNA-188 expression is downregulated in several tumors. However, its function and mechanism in human oral squamous cell carcinoma (OSCC) remains obscure. The present study aims to identify the expression pattern, biological roles, and potential mechanism by which miR-188 dysregulation is associated with oral squamous cell carcinoma. Significant downregulation of miR-188 was observed in OSCC tissues compared with paired normal tissues. In vitro, gain-of-function, loss-of-function experiments were performed to examine the impact of miR-188 on cancer cell proliferation, invasion, and cell cycle progression. Transfection of miR-188 mimics suppressed Detroit 562 cell proliferation, cell cycle progression and invasion, with downregulation of cyclin D1, MMP9, and p-ERK. Transfection of miR-188 inhibitor in FaDu cell line with high endogenous expression exhibited the opposite effects. Using fluorescence reporter assays, we confirmed that SIX1 was a direct target of miR-188 in OSCC cells. Transfection of miR-188 mimics downregulated SIX1 expression. SIX1 siRNA treatment abrogated miR-188 inhibitor-induced cyclin D1 and MMP9 upregulation. In addition, we found that SIX1 was overexpressed in 32 of 80 OSCC tissues. In conclusion, this study indicates that miR-188 downregulation might be associated with oral squamous cell carcinoma progression. miR-188 suppresses proliferation and invasion by targeting SIX1 in oral squamous cell carcinoma cells.

Mel-18 negatively regulates stem cell-like properties through downregulation of miR-21 in gastric cancer.

Science.gov (United States)

Wang, Xiao-Feng; Zhang, Xiao-Wei; Hua, Rui-Xi; Du, Yi-Qun; Huang, Ming-Zhu; Liu, Yong; Cheng, Yu Fang; Guo, Wei-Jian

2016-09-27

Mel-18, a polycomb group protein, has been reported to act as a tumor suppressor and be down-regulated in several human cancers including gastric cancer. It was also found that Mel-18 negatively regulates self-renewal of hematopoietic stem cells and breast cancer stem cells (CSCs). This study aimed to clarify its role in gastric CSCs and explore the mechanisms. We found that low-expression of Mel-18 was correlated with poor prognosis and negatively correlated with overexpression of stem cell markers Oct4, Sox2, and Gli1 in 101 gastric cancer tissues. Mel-18 was down-regulated in cultured spheroid cells, which possess CSCs, and overexpression of Mel-18 inhibits cells sphere-forming ability and tumor growth in vivo. Besides, Mel-18 was lower-expressed in ovary metastatic lesions compared with that in primary lesions of gastric cancer, and Mel-18 overexpression inhibited the migration ability of gastric cancer cells. Interestingly, overexpression of Mel-18 resulted in down-regulation of miR-21 in gastric cancer cells and the expression of Mel-18 was negatively correlated with the expression of miR-21 in gastric cancer tissues. Furthermore, miR-21 overexpression partially restored sphere-forming ability, migration potential and chemo-resistance in Mel-18 overexpressing gastric cancer cells. These results suggests Mel-18 negatively regulates stem cell-like properties through downregulation of miR-21 in gastric cancer cells.

Studies on antigenic competition. Efforts to identify the cellular basis of competition using a cell transfer system

International Nuclear Information System (INIS)

McArthur, W.P.; Siskind, G.W.; Thorbecke, G.J.

1974-01-01

Antigenic competition was studied in a cell transfer system. The effect of reconstituting lethally irradiated mice with various numbers of thymus or bone marrow cells on the extent of antigenic competition was evaluated. Brucella or burro erythrocytes both caused inhibition of the immune response (Plaque-forming cell) to sheep erythrocytes when given two days prior to the test antigen. Varying the dose of thymus cells, or of bone marrow cells did not alter the degree of competition. Competition was observed even when the competing antigen was injected with bone marrow cells alone two days before the test antigen and thymus cells. The results suggest that mechanisms other than T-cell activation alone must be considered as operative in some models of antigenic competition

Allopurinol reduces antigen-specific and polyclonal activation of human T cells

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Damián ePérez-Mazliah

2012-09-01

Full Text Available Allopurinol is the most popular commercially available xanthine oxidase inhibitor and it is widely used for treatment of symptomatic hyperuricaemia, or gout. Although, several anti-inflammatory actions of allopurinol have been demonstrated in vivo and in vitro, there have been few studies on the action of allopurinol on T cells. In the current study, we have assessed the effect of allopurinol on antigen-specific and mitogen-driven activation and cytokine production in human T cells. Allopurinol markedly decreased the frequency of IFN-γ and IL-2-producing T cells, either after polyclonal or antigen-specific stimulation with Herpes Simplex virus 1, Influenza virus, tetanus toxoid and Trypanosoma cruzi-derived antigens. Allopurinol attenuated CD69 upregulation after CD3 and CD28 engagement and significantly reduced the levels of spontaneous and mitogen-induced intracellular reactive oxygen species in T cells. The diminished T cell activation and cytokine production in the presence of allopurinol support a direct action of allopurinol on human T cells, offering a potential pharmacological tool for the management of cell-mediated inflammatory diseases.

Despite disorganized synapse structure, Th2 cells maintain directional delivery of CD40L to antigen-presenting B cells.

Science.gov (United States)

Gardell, Jennifer L; Parker, David C

2017-01-01

Upon recognition of peptide displayed on MHC molecules, Th1 and Th2 cells form distinct immunological synapse structures. Th1 cells have a bull's eye synapse structure with TCR/ MHC-peptide interactions occurring central to a ring of adhesion molecules, while Th2 cells have a multifocal synapse with small clusters of TCR/MHC interactions throughout the area of T cell/antigen-presenting cell interaction. In this study, we investigated whether this structural difference in the immunological synapse affects delivery of T cell help. The immunological synapse is thought to ensure antigen-specific delivery of cytolytic granules and killing of target cells by NK cells and cytolytic T cells. In helper T cells, it has been proposed that the immunological synapse may direct delivery of other effector molecules including cytokines. CD40 ligand (CD40L) is a membrane-bound cytokine essential for antigen-specific T cell help for B cells in the antibody response. We incubated Th1 and Th2 cells overnight with a mixture of antigen-presenting and bystander B cells, and the delivery of CD40L to B cells and subsequent B cell responses were compared. Despite distinct immunological synapse structures, Th1 and Th2 cell do not differ in their ability to deliver CD40L and T cell help in an antigen-specific fashion, or in their susceptibility to inhibition of help by a blocking anti-CD40L antibody.

Co-delivery of PLGA encapsulated invariant NKT cell agonist with antigenic protein induce strong T cell-mediated antitumor immune responses

NARCIS (Netherlands)

Dolen, Y.; Kreutz, M.; Gileadi, U.; Tel, J.; Vasaturo, A.; Dinther, E.A.W. van; Hout-Kuijer, M.A. van; Cerundolo, V.; Figdor, C.G.

2016-01-01

Antitumor immunity can be enhanced by the coordinated release and delivery of antigens and immune-stimulating agents to antigen-presenting cells via biodegradable vaccine carriers. So far, encapsulation of TLR ligands and tumor-associated antigens augmented cytotoxic T cell (CTLs) responses. Here,

Blockade of CD7 expression in T cells for effective chimeric antigen receptor targeting of T-cell malignancies.

Science.gov (United States)

Png, Yi Tian; Vinanica, Natasha; Kamiya, Takahiro; Shimasaki, Noriko; Coustan-Smith, Elaine; Campana, Dario

2017-11-28

Effective immunotherapies for T-cell malignancies are lacking. We devised a novel approach based on chimeric antigen receptor (CAR)-redirected T lymphocytes. We selected CD7 as a target because of its consistent expression in T-cell acute lymphoblastic leukemia (T-ALL), including the most aggressive subtype, early T-cell precursor (ETP)-ALL. In 49 diagnostic T-ALL samples (including 14 ETP-ALL samples), median CD7 expression was >99%; CD7 expression remained high at relapse (n = 14), and during chemotherapy (n = 54). We targeted CD7 with a second-generation CAR (anti-CD7-41BB-CD3ζ), but CAR expression in T lymphocytes caused fratricide due to the presence of CD7 in the T cells themselves. To downregulate CD7 and control fratricide, we applied a new method (protein expression blocker [PEBL]), based on an anti-CD7 single-chain variable fragment coupled with an intracellular retention domain. Transduction of anti-CD7 PEBL resulted in virtually instantaneous abrogation of surface CD7 expression in all transduced T cells; 2.0% ± 1.7% were CD7 + vs 98.1% ± 1.5% of mock-transduced T cells (n = 5; P < .0001). PEBL expression did not impair T-cell proliferation, interferon-γ and tumor necrosis factor-α secretion, or cytotoxicity, and eliminated CAR-mediated fratricide. PEBL-CAR T cells were highly cytotoxic against CD7 + leukemic cells in vitro and were consistently more potent than CD7 + T cells spared by fratricide. They also showed strong anti-leukemic activity in cell line- and patient-derived T-ALL xenografts. The strategy described in this study fits well with existing clinical-grade cell manufacturing processes and can be rapidly implemented for the treatment of patients with high-risk T-cell malignancies.

Immunofluorescent staining of nuclear antigen in lymphoid cells transformed by Herpesvirus papio (HVP).

Science.gov (United States)

Schmitz, H

1981-01-01

An improved fixation method for antigen detection in lymphoblastoid cells is described. Herpesvirus papio nuclear antigen (HUPNA) could be stained in several transformed lymphoid cell lines by anti-complement immunofluorescence (ACIF). Antibody to HUPNA was detected in many human sera containing antibodies to Epstein-Barr virus capsid and nuclear antigen (EBNA). Rheumatoid arthritis sera showed a high incidence of both anti-EBNA and anti-HUPNA antibodies.

The leukocyte common antigen (CD45) on human pre-B leukemia cells: variant glycoprotein form expression during the cell exposure to phorbol ester is blocked by a nonselective protein kinase inhibitor H7

International Nuclear Information System (INIS)

Duraj, J.; Sedlak, J.; Chorvath, B.; Rauko, P.

1997-01-01

The human pre-B acute lymphoblastic leukemia cell line REH6 was utilized for characterization of CD45 glycoprotein by monoclonal antibodies (mAb) recognizing four distinct CD45 antigen specificities, i.e. nonrestricted CD45, restricted, CD45RA, CD45RB and CD45R0. Immunoprecipitation revealed two antigen specificities on REH6 cells of m.w. 220 kDa and 190 kDa, both presenting wide range of isoelectric point pI∼6.0-7.5. Nonrestricted CD45 epitopes were not affected by the sialyl acid cleavage with sodium meta-periodate or neuraminidase, but were sensitive to both, tunicamycin, the N-glycosylation inhibitor and monensin, an inhibitor of protein transport through the Golgi compartment. O-sialoglycoprotein endopeptidase from Pasteurella haemolytica A1 partially cleaved CD45RA and CD45RB epitopes, while nonrestricted CD45 determinants were not affected by this enzyme. Limited proteolysis of this antigen resulted in the appearance of 160-180 kDa peptide domains which retained CD45 epitopes. Further, the treatment of cells with phorbol myristate acetate (PMA) induced marked down-regulation of 220 and 190 kDa isoforms and the appearance of new 210, 180 and 170 kDa variant glycoprotein forms which were not found on parental cells. This PMA effect was not accompanied by the programmed cell death and was markedly blocked by a nonselective protein kinase (PK) inhibitor iso-quinoline sulfonamide H7. Modulation of CD45 by phorbol esters might serve as an in vitro model for an additional insight into the function of CD45 in hematopoietic cells. (author)

Downregulation of MMP1 in MDS-derived mesenchymal stromal cells reduces the capacity to restrict MDS cell proliferation.

Science.gov (United States)

Zhao, Sida; Zhao, Youshan; Guo, Juan; Fei, Chengming; Zheng, Qingqing; Li, Xiao; Chang, Chunkang

2017-03-06

The role of mesenchymal stromal cells (MSCs) in the pathogenesis of myelodysplastic syndromes (MDS) has been increasingly addressed, but has yet to be clearly elucidated. In this investigation, we found that MDS cells proliferated to a greater extent on MDS-derived MSCs compared to normal MSCs. Matrix metalloproteinase 1(MMP1), which was downregulated in MDS-MSCs, was identified as an inhibitory factor of MDS cell proliferation, given that treatment with an MMP1 inhibitor or knock-down of MMP1 in normal MSCs resulted in increased MDS cell proliferation. Further investigations indicated that MMP1 induced apoptosis of MDS cells by interacting with PAR1 and further activating the p38 MAPK pathway. Inhibition of either PAR1 or p38 MAPK can reverse the apoptosis-inducing effect of MMP1. Taken together, these data indicate that downregulation of MMP1 in MSCs of MDS patients may contribute to the reduced capacity of MSCs to restrict MDS cell proliferation, which may account for the malignant proliferation of MDS cells.

Sperm associated antigen 9 plays an important role in bladder transitional cell carcinoma.

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Deepika Kanojia

Full Text Available BACKGROUND: Majority of bladder cancer deaths are caused due to transitional cell carcinoma (TCC which is the most prevalent and chemoresistant malignancy of urinary bladder. Therefore, we analyzed the role of Sperm associated antigen 9 (SPAG9 in bladder TCC. METHODOLOGY AND FINDINGS: We examined SPAG9 expression and humoral response in 125 bladder TCC patients. Four bladder cancer cell lines were assessed for SPAG9 expression. In addition, we investigated the effect of SPAG9 ablation on cellular proliferation, cell cycle, migration and invasion in UM-UC-3 bladder cancer cells by employing gene silencing approach. Our SPAG9 gene and protein expression analysis revealed SPAG9 expression in 81% of bladder TCC tissue specimens. High SPAG9 expression (>60% SPAG9 positive cells was found to be significantly associated with superficial non-muscle invasive stage (P = 0.042 and low grade tumors (P = 0.002 suggesting SPAG9 putative role in early spread and tumorigenesis. Humoral response against SPAG9 was observed in 95% of patients found positive for SPAG9 expression. All four bladder cancer cell lines revealed SPAG9 expression. In addition, SPAG9 gene silencing in UM-UC-3 cells resulted in induction of G0-G1 arrest characterized by up-regulation of p16 and p21 and consequent down-regulation of cyclin E, cyclin D and cyclin B, CDK4 and CDK1. Further, SPAG9 gene silencing also resulted in reduction in cellular growth, and migration and invasion ability of cancer cells in vitro. CONCLUSIONS: Collectively, our data in clinical specimens indicated that SPAG9 is potential biomarker and therapeutic target for bladder TCC.

Antibody-antigen-adjuvant conjugates enable co-delivery of antigen and adjuvant to dendritic cells in cis but only have partial targeting specificity

NARCIS (Netherlands)

Kreutz, M.; Giquel, B.; Hu, Q.; Abuknesha, R.; Uematsu, S.; Akira, S.; Nestle, F.O.; Diebold, S.S.

2012-01-01

Antibody-antigen conjugates, which promote antigen-presentation by dendritic cells (DC) by means of targeted delivery of antigen to particular DC subsets, represent a powerful vaccination approach. To ensure immunity rather than tolerance induction the co-administration of a suitable adjuvant is

Cell Wall-Associated Protein Antigens of Streptococcus salivarius: Purification, Properties, and Function in Adherence

OpenAIRE

Weerkamp, Anton H.; Jacobs, Ton

1982-01-01

Three cell wall-associated protein antigens (antigens b, c, and d) were isolated from mutanolysin-solubilized cell walls of Streptococcus salivarius HB and purified to apparent homogeneity by a combination of ion-exchange chromatography, gel filtration, and immunoadsorption chromatography. Antigens b and c were also isolated from culture supernatants. Antigen b consisted of more than 80% protein and had an apparent molecular weight as determined by sodium dodecyl sulfate-polyacrylamide gel el...

Expression of cathepsins B, L, S, and D by gastric epithelial cells implicates them as antigen presenting cells in local immune responses.

Science.gov (United States)

Barrera, C; Ye, G; Espejo, R; Gunasena, S; Almanza, R; Leary, J; Crowe, S; Ernst, P; Reyes, V E

2001-10-01

Helicobacter pylori infection is linked to chronic gastritis, peptic ulcer and gastric carcinoma. During H. pylori infection, class II MHC expression by the gastric epithelium increases, as does the number of local CD4(+) T cells, which appear to be important in the associated pathogenesis. These observations suggested that the epithelium might present antigens to T cells. Thus, we sought to determine whether gastric epithelial cells process antigens to establish their function as local antigen presenting cells (APC). We examined a panel of gastric epithelial cell lines for expression of the antigen processing cathepsins B (CB), L (CL), S (CS), and D (CD). The mRNA for these enzymes were detected by RT-PCR and the enzymes in the gastric epithelial cells were identified by various independent methods. We corroborated the expression of CB and CD on gastric epithelial cells from human biopsy samples. The functions of these proteases were confirmed by assessing their ability to digest ovalbumin, a conventional dietary antigen, and proteins from H. pylori. In summary, multiple lines of evidence suggest gastric epithelial cells process antigens for presentation to CD4(+) T cells. To our knowledge, these are the first studies to document the antigen processing capacity of human gastric epithelial cells.

Do ABO blood group antigens hamper the therapeutic efficacy of mesenchymal stromal cells?

Science.gov (United States)

Moll, Guido; Hult, Annika; von Bahr, Lena; Alm, Jessica J; Heldring, Nina; Hamad, Osama A; Stenbeck-Funke, Lillemor; Larsson, Stella; Teramura, Yuji; Roelofs, Helene; Nilsson, Bo; Fibbe, Willem E; Olsson, Martin L; Le Blanc, Katarina

2014-01-01

Investigation into predictors for treatment outcome is essential to improve the clinical efficacy of therapeutic multipotent mesenchymal stromal cells (MSCs). We therefore studied the possible harmful impact of immunogenic ABO blood groups antigens - genetically governed antigenic determinants - at all given steps of MSC-therapy, from cell isolation and preparation for clinical use, to final recipient outcome. We found that clinical MSCs do not inherently express or upregulate ABO blood group antigens after inflammatory challenge or in vitro differentiation. Although antigen adsorption from standard culture supplements was minimal, MSCs adsorbed small quantities of ABO antigen from fresh human AB plasma (ABP), dependent on antigen concentration and adsorption time. Compared to cells washed in non-immunogenic human serum albumin (HSA), MSCs washed with ABP elicited stronger blood responses after exposure to blood from healthy O donors in vitro, containing high titers of ABO antibodies. Clinical evaluation of hematopoietic stem cell transplant (HSCT) recipients found only very low titers of anti-A/B agglutination in these strongly immunocompromised patients at the time of MSC treatment. Patient analysis revealed a trend for lower clinical response in blood group O recipients treated with ABP-exposed MSC products, but not with HSA-exposed products. We conclude, that clinical grade MSCs are ABO-neutral, but the ABP used for washing and infusion of MSCs can contaminate the cells with immunogenic ABO substance and should therefore be substituted by non-immunogenic HSA, particularly when cells are given to immunocompentent individuals.

Cord blood stem cell-mediated induction of apoptosis in glioma downregulates X-linked inhibitor of apoptosis protein (XIAP.

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Venkata Ramesh Dasari

2010-07-01

Full Text Available XIAP (X-linked inhibitor of apoptosis protein is one of the most important members of the apoptosis inhibitor family. XIAP is upregulated in various malignancies, including human glioblastoma. It promotes invasion, metastasis, growth and survival of malignant cells. We hypothesized that downregulation of XIAP by human umbilical cord blood mesenchymal stem cells (hUCBSC in glioma cells would cause them to undergo apoptotic death.We observed the effect of hUCBSC on two malignant glioma cell lines (SNB19 and U251 and two glioma xenograft cell lines (4910 and 5310. In co-cultures of glioma cells with hUCBSC, proliferation of glioma cells was significantly inhibited. This is associated with increased cytotoxicity of glioma cells, which led to glioma cell death. Stem cells induced apoptosis in glioma cells, which was evaluated by TUNEL assay, FACS analyses and immunoblotting. The induction of apoptosis is associated with inhibition of XIAP in co-cultures of hUCBSC. Similar results were obtained by the treatment of glioma cells with shRNA to downregulate XIAP (siXIAP. Downregulation of XIAP resulted in activation of caspase-3 and caspase-9 to trigger apoptosis in glioma cells. Apoptosis is characterized by the loss of mitochondrial membrane potential and upregulation of mitochondrial apoptotic proteins Bax and Bad. Cell death of glioma cells was marked by downregulation of Akt and phospho-Akt molecules. We observed similar results under in vivo conditions in U251- and 5310-injected nude mice brains, which were treated with hUCBSC. Under in vivo conditions, Smac/DIABLO was found to be colocalized in the nucleus, showing that hUCBSC induced apoptosis is mediated by inhibition of XIAP and activation of Smac/DIABLO.Our results indicate that downregulation of XIAP by hUCBSC treatment induces apoptosis, which led to the death of the glioma cells and xenograft cells. This study demonstrates the therapeutic potential of XIAP and hUCBSC to treat malignant

The androgen receptor controls expression of the cancer-associated sTn antigen and cell adhesion through induction of ST6GalNAc1 in prostate cancer

Science.gov (United States)

Munkley, Jennifer; Oltean, Sebastian; Vodák, Daniel; Wilson, Brian T.; Livermore, Karen E.; Zhou, Yan; Star, Eleanor; Floros, Vasileios I.; Johannessen, Bjarne; Knight, Bridget; McCullagh, Paul; McGrath, John; Crundwell, Malcolm; Skotheim, Rolf I.; Robson, Craig N.; Leung, Hing Y.; Harries, Lorna W.; Rajan, Prabhakar; Mills, Ian G.; Elliott, David J.

2015-01-01

Patterns of glycosylation are important in cancer, but the molecular mechanisms that drive changes are often poorly understood. The androgen receptor drives prostate cancer (PCa) development and progression to lethal metastatic castration-resistant disease. Here we used RNA-Seq coupled with bioinformatic analyses of androgen-receptor (AR) binding sites and clinical PCa expression array data to identify ST6GalNAc1 as a direct and rapidly activated target gene of the AR in PCa cells. ST6GalNAc1 encodes a sialytransferase that catalyses formation of the cancer-associated sialyl-Tn antigen (sTn), which we find is also induced by androgen exposure. Androgens induce expression of a novel splice variant of the ST6GalNAc1 protein in PCa cells. This splice variant encodes a shorter protein isoform that is still fully functional as a sialyltransferase and able to induce expression of the sTn-antigen. Surprisingly, given its high expression in tumours, stable expression of ST6GalNAc1 in PCa cells reduced formation of stable tumours in mice, reduced cell adhesion and induced a switch towards a more mesenchymal-like cell phenotype in vitro. ST6GalNAc1 has a dynamic expression pattern in clinical datasets, being significantly up-regulated in primary prostate carcinoma but relatively down-regulated in established metastatic tissue. ST6GalNAc1 is frequently upregulated concurrently with another important glycosylation enzyme GCNT1 previously associated with prostate cancer progression and implicated in Sialyl Lewis X antigen synthesis. Together our data establishes an androgen-dependent mechanism for sTn antigen expression in PCa, and are consistent with a general role for the androgen receptor in driving important coordinate changes to the glycoproteome during PCa progression. PMID:26452038

Application of Adoptive T-Cell Therapy Using Tumor Antigen-Specific T-Cell Receptor Gene Transfer for the Treatment of Human Leukemia

Directory of Open Access Journals (Sweden)

Toshiki Ochi

2010-01-01

Full Text Available The last decade has seen great strides in the field of cancer immunotherapy, especially the treatment of melanoma. Beginning with the identification of cancer antigens, followed by the clinical application of anti-cancer peptide vaccination, it has now been proven that adoptive T-cell therapy (ACT using cancer antigen-specific T cells is the most effective option. Despite the apparent clinical efficacy of ACT, the timely preparation of a sufficient number of cancer antigen-specific T cells for each patient has been recognized as its biggest limitation. Currently, therefore, attention is being focused on ACT with engineered T cells produced using cancer antigen-specific T-cell receptor (TCR gene transfer. With regard to human leukemia, ACT using engineered T cells bearing the leukemia antigen-specific TCR gene still remains in its infancy. However, several reports have provided preclinical data on TCR gene transfer using Wilms' tumor gene product 1 (WT1, and also preclinical and clinical data on TCR gene transfer involving minor histocompatibility antigen, both of which have been suggested to provide additional clinical benefit. In this review, we examine the current status of anti-leukemia ACT with engineered T cells carrying the leukemia antigen-specific TCR gene, and discuss the existing barriers to progress in this area.

Whole tumor antigen vaccination using dendritic cells: Comparison of RNA electroporation and pulsing with UV-irradiated tumor cells

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Benencia Fabian

2008-04-01

Full Text Available Abstract Because of the lack of full characterization of tumor associated antigens for solid tumors, whole antigen use is a convenient approach to tumor vaccination. Tumor RNA and apoptotic tumor cells have been used as a source of whole tumor antigen to prepare dendritic cell (DC based tumor vaccines, but their efficacy has not been directly compared. Here we compare directly RNA electroporation and pulsing of DCs with whole tumor cells killed by ultraviolet (UV B radiation using a convenient tumor model expressing human papilloma virus (HPV E6 and E7 oncogenes. Although both approaches led to DCs presenting tumor antigen, electroporation with tumor cell total RNA induced a significantly higher frequency of tumor-reactive IFN-gamma secreting T cells, and E7-specific CD8+ lymphocytes compared to pulsing with UV-irradiated tumor cells. DCs electroporated with tumor cell RNA induced a larger tumor infiltration by T cells and produced a significantly stronger delay in tumor growth compared to DCs pulsed with UV-irradiated tumor cells. We conclude that electroporation with whole tumor cell RNA and pulsing with UV-irradiated tumor cells are both effective in eliciting antitumor immune response, but RNA electroporation results in more potent tumor vaccination under the examined experimental conditions.

Age-Associated Decline in Thymic B Cell Expression of Aire and Aire-Dependent Self-Antigens

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Sergio Cepeda

2018-01-01

Full Text Available Although autoimmune disorders are a significant source of morbidity and mortality in older individuals, the mechanisms governing age-associated increases in susceptibility remain incompletely understood. Central T cell tolerance is mediated through presentation of self-antigens by cells constituting the thymic microenvironment, including epithelial cells, dendritic cells, and B cells. Medullary thymic epithelial cells (mTECs and B cells express distinct cohorts of self-antigens, including tissue-restricted self-antigens (TRAs, such that developing T cells are tolerized to antigens from peripheral tissues. We find that expression of the TRA transcriptional regulator Aire, as well as Aire-dependent genes, declines with age in thymic B cells in mice and humans and that cell-intrinsic and cell-extrinsic mechanisms contribute to the diminished capacity of peripheral B cells to express Aire within the thymus. Our findings indicate that aging may diminish the ability of thymic B cells to tolerize T cells, revealing a potential mechanistic link between aging and autoimmunity.

Skin-Resident T Cells Drive Dermal Dendritic Cell Migration in Response to Tissue Self-Antigen.

Science.gov (United States)

Ali, Niwa; Zirak, Bahar; Truong, Hong-An; Maurano, Megan M; Gratz, Iris K; Abbas, Abul K; Rosenblum, Michael D

2018-05-01

Migratory dendritic cell (DC) subsets deliver tissue Ags to draining lymph nodes (DLNs) to either initiate or inhibit T cell-mediated immune responses. The signals mediating DC migration in response to tissue self-antigen are largely unknown. Using a mouse model of inducible skin-specific self-antigen expression, we demonstrate that CD103 + dermal DCs (DDCs) rapidly migrate from skin to skin DLN (SDLNs) within the first 48 h after Ag expression. This window of time was characterized by the preferential activation of tissue-resident Ag-specific effector T cells (Teffs), with no concurrent activation of Ag-specific Teffs in SDLNs. Using genetic deletion and adoptive transfer approaches, we show that activation of skin-resident Teffs is required to drive CD103 + DDC migration in response to tissue self-antigen and this Batf3-dependent DC population is necessary to mount a fulminant autoimmune response in skin. Conversely, activation of Ag-specific Teffs in SDLNs played no role in DDC migration. Our studies reveal a crucial role for skin-resident T cell-derived signals, originating at the site of self-antigen expression, to drive DDC migration during the elicitation phase of an autoimmune response. Copyright © 2018 by The American Association of Immunologists, Inc.

Interleukins 1alpha and 1beta secreted by some melanoma cell lines strongly reduce expression of MITF-M and melanocyte differentiation antigens.

Science.gov (United States)

Kholmanskikh, Olga; van Baren, Nicolas; Brasseur, Francis; Ottaviani, Sabrina; Vanacker, Julie; Arts, Nathalie; van der Bruggen, Pierre; Coulie, Pierre; De Plaen, Etienne

2010-10-01

We report that melanoma cell lines expressing the interleukin-1 receptor exhibit 4- to 10-fold lower levels of mRNA of microphthalmia-associated transcription factor (MITF-M) when treated with interleukin-1beta. This effect is NF-kappaB and JNK-dependent. MITF-M regulates the expression of melanocyte differentiation genes such as MLANA, tyrosinase and gp100, which encode antigens recognized on melanoma cells by autologous cytolytic T lymphocytes. Accordingly, treating some melanoma cells with IL-1beta reduced by 40-100% their ability to activate such antimelanoma cytolytic T lymphocytes. Finally, we observed large amounts of biologically active IL-1alpha or IL-1beta secreted by two melanoma cell lines that did not express MITF-M, suggesting an autocrine MITF-M downregulation. We estimate that approximately 13% of melanoma cell lines are MITF-M-negative and secrete IL-1 cytokines. These results indicate that the repression of melanocyte-differentiation genes by IL-1 produced by stromal cells or by tumor cells themselves may represent an additional mechanism of melanoma immune escape.

Antigen-Specific lgA B Memory Cell Responses to Shigella Antigens Elicited in Volunteers Immunized with Live Attenuated Shigella flexneri 2a Oral Vaccine Candidates

Science.gov (United States)

2011-01-01

167. [10] E.V. Oaks, T.L. Hale, S.B. Formal, Serum immune response to Shigella protein antigens in rhesus monkeys and humans infected with Shigella ...cell responses to Shigella antigens elicited in volunteers immunized with live attenuated Shigella flexneri 2a oral vaccine candidates J.K. Simona,b... Shigella ;. B cell memory; Immunoglobulin lgA; Mucosal immunity Abstract We studied the induction of antigen-specific lgA memory B cells (BM) in

The perivascular phagocyte of the mouse pineal gland: An antigen-presenting cell

DEFF Research Database (Denmark)

Møller, Morten; Rath, Martin F; Klein, David C

2006-01-01

The perivascular space of the rat pineal gland is known to contain phagocytic cells that are immunoreactive for leukocyte antigens, and thus they appear to belong to the macrophage/microglial cell line. These cells also contain MHC class II proteins. We investigated this cell type in the pineal g...... for MHC class II protein and for CD68, a marker of monocytes/phagocytes. This study verifies that perivascular phagocytes with antigen-presenting properties are present in the mouse pineal gland....

Expression of the Gastrin-Releasing Peptide Receptor, the Prostate Stem Cell Antigen and the Prostate-Specific Membrane Antigen in Lymph Node and Bone Metastases of Prostate Cancer

NARCIS (Netherlands)

Ananias, Hildo J. K.; van den Heuvel, Marius C.; Helfrich, Wijnand; de Jong, Igle J.

2009-01-01

OBJECTIVE. Cell membrane antigens like the gastrin-releasing peptide receptor (GRPR), the prostate stem cell antigen (PSCA), and the prostate-specific membrane antigen (PSMA), expressed in prostate cancer, are attractive targets for new therapeutic and diagnostic applications. Therefore, we

Rapid desensitization induces internalization of antigen-specific IgE on mouse mast cells.

Science.gov (United States)

Oka, Tatsuya; Rios, Eon J; Tsai, Mindy; Kalesnikoff, Janet; Galli, Stephen J

2013-10-01

Rapid desensitization transiently prevents severe allergic reactions, allowing administration of life-saving therapies in previously sensitized patients. However, the mechanisms underlying successful rapid desensitization are not fully understood. We sought to investigate whether the mast cell (MC) is an important target of rapid desensitization in mice sensitized to exhibit IgE-dependent passive systemic anaphylaxis in vivo and to investigate the antigen specificity and underlying mechanisms of rapid desensitization in our mouse model. C57BL/6 mice (in vivo) or primary isolated C57BL/6 mouse peritoneal mast cells (PMCs; in vitro) were passively sensitized with antigen-specific anti-2,4-dinitrophenyl IgE, anti-ovalbumin IgE, or both. MCs were exposed over a short period of time to increasing amounts of antigen (2,4-dinitrophenyl-human serum albumin or ovalbumin) in the presence of extracellular calcium in vitro or by means of intravenous administration to sensitized mice in vivo before challenging the mice with or exposing the PMCs to optimal amounts of specific or irrelevant antigen. Rapidly exposing mice or PMCs to progressively increasing amounts of specific antigen inhibited the development of antigen-induced hypothermia in sensitized mice in vivo and inhibited antigen-induced PMC degranulation and prostaglandin D2 synthesis in vitro. Such MC hyporesponsiveness was induced antigen-specifically and was associated with a significant reduction in antigen-specific IgE levels on MC surfaces. Rapidly exposing MCs to progressively increasing amounts of antigen can both enhance the internalization of antigen-specific IgE on the MC surface and also desensitize these cells in an antigen-specific manner in vivo and in vitro. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Downregulation of miR-497 promotes tumor growth and angiogenesis by targeting HDGF in non-small cell lung cancer

International Nuclear Information System (INIS)

Zhao, Wen-yan; Wang, Yan; An, Zhong-jun; Shi, Chang-guo; Zhu, Guang-ai; Wang, Bin; Lu, Ming-yan; Pan, Chang-kun; Chen, Peng

2013-01-01

Highlights: •MiR-497 is down-regulated in NSCLC cells and tissues. •MiR-497 inhibits NSCLC cell growth in vitro. •HDGF is a target gene of miR-497. •MiR-497 inhibits NSCLC cell growth by downregulating HDGF. •miR-497 inhibits tumor growth and angiogenesis in vivo. -- Abstract: MicroRNAs (miRNAs) play important roles in the development of various cancers. MiRNA-497 functions as a tumor-suppressor that is downregulated in several malignancies; however, its role in non-small cell lung cancer (NSCLC) has not been examined in detail. Here, we showed that miR-497 is downregulated in NSCLC tumors and cell lines and its ectopic expression significantly inhibits cell proliferation and colony formation. Integrated analysis identified HDGF as a downstream target of miR-497, and the downregulation of HDGF by miR-497 overexpression confirmed their association. Rescue experiments showed that the inhibitory effect of miR-497 on cell proliferation and colony formation is predominantly mediated by the modulation of HDGF levels. Furthermore, tumor samples from NSCLC patients showed an inverse relationship between miR-497 and HDGF levels, and ectopic expression of miR-497 significantly inhibited tumor growth and angiogenesis in a SCID mouse xenograft model. Our results suggest that miR-497 may serve as a biomarker in NSCLC, and the modulation of its activity may represent a novel therapeutic strategy for the treatment of NSCLC patients

Human Parvovirus B19 Induced Apoptotic Bodies Contain Altered Self-Antigens that are Phagocytosed by Antigen Presenting Cells

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Thammasri, Kanoktip; Rauhamäki, Sanna; Wang, Liping; Filippou, Artemis; Kivovich, Violetta; Marjomäki, Varpu; Naides, Stanley J.; Gilbert, Leona

2013-01-01

Human parvovirus B19 (B19V) from the erythrovirus genus is known to be a pathogenic virus in humans. Prevalence of B19V infection has been reported worldwide in all seasons, with a high incidence in the spring. B19V is responsible for erythema infectiosum (fifth disease) commonly seen in children. Its other clinical presentations include arthralgia, arthritis, transient aplastic crisis, chronic anemia, congenital anemia, and hydrops fetalis. In addition, B19V infection has been reported to trigger autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. However, the mechanisms of B19V participation in autoimmunity are not fully understood. B19V induced chronic disease and persistent infection suggests B19V can serve as a model for viral host interactions and the role of viruses in the pathogenesis of autoimmune diseases. Here we investigate the involvement of B19V in the breakdown of immune tolerance. Previously, we demonstrated that the non-structural protein 1 (NS 1) of B19V induces apoptosis in non-permissive cells lines and that this protein can cleave host DNA as well as form NS1-DNA adducts. Here we provide evidence that through programmed cell death, apoptotic bodies (ApoBods) are generated by B19V NS1 expression in a non-permissive cell line. Characterization of purified ApoBods identified potential self-antigens within them. In particular, signature self-antigens such as Smith, ApoH, DNA, histone H4 and phosphatidylserine associated with autoimmunity were present in these ApoBods. In addition, when purified ApoBods were introduced to differentiated macrophages, recognition, engulfment and uptake occurred. This suggests that B19V can produce a source of self-antigens for immune cell processing. The results support our hypothesis that B19V NS1-DNA adducts, and nucleosomal and lysosomal antigens present in ApoBods created in non-permissive cell lines, are a source of self-antigens. PMID:23776709

MYCN: from oncoprotein to tumor-associated antigen

International Nuclear Information System (INIS)

Pistoia, Vito; Morandi, Fabio; Pezzolo, Annalisa; Raffaghello, Lizzia; Prigione, Ignazia

2012-01-01

MYCN is a well-known oncogene over-expressed in different human malignancies including neuroblastoma (NB), rhabdomyosarcoma, medulloblastoma, astrocytoma, Wilms’ tumor, and small cell lung cancer. In the case of NB, MYCN amplification is an established biomarker of poor-prognosis. MYCN belongs to a family of transcription factors (the most important of which is C-MYC) that show a high degree of homology. Down-regulation of MYC protein expression leads to tumor regression in animal models, indicating that MYC proteins represent interesting therapeutic targets. Pre-requisites for a candidate tumor-associated antigen (TAA) to be targeted by immunotherapeutic approaches are the following, (i) expression should be tumor-restricted, (ii) the putative TAA should be up-regulated in cancer cells, and (iii) protein should be processed into immunogenic peptides capable of associating to major histocompatibility complex molecules with high affinity. Indeed, the MYCN protein is not expressed in human adult tissues and up-regulated variably in NB cells, and MYCN peptides capable of associating to HLA-A1 or HLA-A2 molecules with high affinity have been identified. Thus the MYCN protein qualifies as putative TAA in NB. Additional issues that determine the feasibility of targeting a putative TAA with cytotoxic T lymphocytes (CTLs) and will be here discussed are the following, (i) the inadequacy of tumor cells per se to act as antigen-presenting cells witnessed, in the case of NB cells, by the low to absent expression of HLA class I molecules, the lack of co-stimulatory molecules and multiple defects in the HLA class I related antigen processing machinery, and (ii) the immune evasion mechanisms operated by cancer cells to fool the host immune system, such as up-regulation of soluble immunosuppressive molecules (e.g., soluble MICA and HLA-G in the case of NB) or generation of immunosuppressive cells in the tumor microenvironment. A final issue that deserves consideration is the

MYCN: From Oncoprotein To Tumor-Associated Antigen

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Vito ePistoia

2012-11-01

Full Text Available MYCN is a well known oncogene overexpressed in different human malignancies including neuroblastoma, rhabdomyosarcoma, medulloblastoma, astrocytoma, Wilms’ tumor and small cell lung cancer. In the case of neuroblastoma (NB, MYCN amplification is an established biomarker of poor prognosis. MYCN belongs to a family of transcription factors (the most important of which is CMYC that show a high degree of homology. Downregulation of MYC protein expression leads to tumor regression in animal models, indicating that MYC proteins represent interesting therapeutic targets.Pre-requisites for a candidate tumor-associated antigen (TAA to be targeted by immunotherapeutic approaches are the following, i expression should be tumor-restricted, ii the putative TAA should be up-regulated in cancer cells and iii protein should be processed into immunogenic peptides capable of associating to MHC molecules with high affinity. Indeed, the MYCN protein is not expressed in human adult tissues and upregulated variably in NB cells, and MYCN peptides capable of associating to HLA-A1 or –A2 molecules with high affinity have been identified. Thus the MYCN protein qualifies as putative TAA in NB.Additional issues that determine the feasibility of targeting a putative TAA with cytotoxic T lymphocytes (CTL and will be here discussed are the following, i the inadequacy of tumor cells per se to act as antigen-presenting cells witnessed, in the case of NB cells, by the low to absent expression of HLA- class I molecules, the lack of costimulatory molecules and multiple defects in the HLA class I related antigen processing machinery, and ii the immune evasion mechanisms operated by cancer cells to fool the host immune system, such as up-regulation of soluble immunosuppressive molecules (e.g. soluble MICA and HLA-G in the case of NB or generation of immunosuppressive cells in the tumor microenvironment. A final issue that deserves consideration is the strategy used to generate

MYCN: from oncoprotein to tumor-associated antigen

Energy Technology Data Exchange (ETDEWEB)

Pistoia, Vito; Morandi, Fabio; Pezzolo, Annalisa; Raffaghello, Lizzia; Prigione, Ignazia, E-mail: vitopistoia@ospedale-gaslini.ge.it [Laboratory of Oncology, Translational Research and Laboratory Medicine, G. Gaslini Institute, Genoa (Italy)

2012-11-16

MYCN is a well-known oncogene over-expressed in different human malignancies including neuroblastoma (NB), rhabdomyosarcoma, medulloblastoma, astrocytoma, Wilms’ tumor, and small cell lung cancer. In the case of NB, MYCN amplification is an established biomarker of poor-prognosis. MYCN belongs to a family of transcription factors (the most important of which is C-MYC) that show a high degree of homology. Down-regulation of MYC protein expression leads to tumor regression in animal models, indicating that MYC proteins represent interesting therapeutic targets. Pre-requisites for a candidate tumor-associated antigen (TAA) to be targeted by immunotherapeutic approaches are the following, (i) expression should be tumor-restricted, (ii) the putative TAA should be up-regulated in cancer cells, and (iii) protein should be processed into immunogenic peptides capable of associating to major histocompatibility complex molecules with high affinity. Indeed, the MYCN protein is not expressed in human adult tissues and up-regulated variably in NB cells, and MYCN peptides capable of associating to HLA-A1 or HLA-A2 molecules with high affinity have been identified. Thus the MYCN protein qualifies as putative TAA in NB. Additional issues that determine the feasibility of targeting a putative TAA with cytotoxic T lymphocytes (CTLs) and will be here discussed are the following, (i) the inadequacy of tumor cells per se to act as antigen-presenting cells witnessed, in the case of NB cells, by the low to absent expression of HLA class I molecules, the lack of co-stimulatory molecules and multiple defects in the HLA class I related antigen processing machinery, and (ii) the immune evasion mechanisms operated by cancer cells to fool the host immune system, such as up-regulation of soluble immunosuppressive molecules (e.g., soluble MICA and HLA-G in the case of NB) or generation of immunosuppressive cells in the tumor microenvironment. A final issue that deserves consideration is the

Antigen-Specific Th17 Cells Are Primed by Distinct and Complementary Dendritic Cell Subsets in Oropharyngeal Candidiasis.

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Kerstin Trautwein-Weidner

2015-10-01

Full Text Available Candida spp. can cause severe and chronic mucocutaneous and systemic infections in immunocompromised individuals. Protection from mucocutaneous candidiasis depends on T helper cells, in particular those secreting IL-17. The events regulating T cell activation and differentiation toward effector fates in response to fungal invasion in different tissues are poorly understood. Here we generated a Candida-specific TCR transgenic mouse reactive to a novel endogenous antigen that is conserved in multiple distant species of Candida, including the clinically highly relevant C. albicans and C. glabrata. Using TCR transgenic T cells in combination with an experimental model of oropharyngeal candidiasis (OPC we investigated antigen presentation and Th17 priming by different subsets of dendritic cells (DCs present in the infected oral mucosa. Candida-derived endogenous antigen accesses the draining lymph nodes and is directly presented by migratory DCs. Tissue-resident Flt3L-dependent DCs and CCR2-dependent monocyte-derived DCs collaborate in antigen presentation and T cell priming during OPC. In contrast, Langerhans cells, which are also present in the oral mucosa and have been shown to prime Th17 cells in the skin, are not required for induction of the Candida-specific T cell response upon oral challenge. This highlights the functional compartmentalization of specific DC subsets in different tissues. These data provide important new insights to our understanding of tissue-specific antifungal immunity.

Cell surface antigens of radiation leukemia virus-induced BALB/c leukemias defined by syngeneic cytotoxic T lymphocytes

International Nuclear Information System (INIS)

Kaneko, Yukio; Oettgen, H.F.; Obata, Yuichi; Nakayama, Eiichi.

1989-01-01

Two cell surface antigens of mouse leukemias were defined by BALB/c cytotoxic T lymphocytes (CTL) generated against syngeneic radiation leukemia virus (RadLV)-induced leukemia, BALBRV1 or BALBRVD. Hyperimmunization of BALB/c mice with irradiated leukemias followed by in vitro sensitization of primed spleen cells resulted in the generation of CTL with high killing activity. The specificity of CTL was examined by direct cytotoxicity assays and competitive inhibition assays. A shared cell surface antigen, designated as BALBRV1 antigen, was detected by BALB/c anti-BALBRV1 CTL. BALBRV1 antigen was expressed not only on RadLV-induced BALB/c leukemias except for BALBRVD, but also on spontaneous or X-ray-induced BALB/c leukemias, chemically-induced leukemias with the H-2 d haplotype and some chemically-induced BALB/c sarcomas. In contrast, a unique cell surface antigen, designated as BALBRVD antigen, was detected by BALB/c anti-BALBRVD CTL. BALBRVD antigen was expressed only on BALBRVD, but not on thirty-nine normal lymphoid or tumor cells. These two antigens could be distinguished from those previously defined on Friend, Moloney, Rauscher or Gross murine leukemia virus (MuLV) leukemias, or MuLV-related antigens. Both cytotoxic responses were blocked by antisera against H-2K d , but not H-2D d . The relationship of BALBRV1 antigen and BALBRVD antigen to endogenous MuLV is discussed with regard to the antigenic distribution on tumor cell lines. (author)

Down-Regulation of Desmosomes in Cultured Cells: The Roles of PKC, Microtubules and Lysosomal/Proteasomal Degradation

Science.gov (United States)

McHarg, Selina; Hopkins, Gemma; Lim, Lusiana; Garrod, David

2014-01-01

Desmosomes are intercellular adhesive junctions of major importance for tissue integrity. To allow cell motility and migration they are down-regulated in epidermal wound healing. Electron microscopy indicates that whole desmosomes are internalised by cells in tissues, but the mechanism of down-regulation is unclear. In this paper we provide an overview of the internalisation of half-desmosomes by cultured cells induced by calcium chelation. Our results show that: (i) half desmosome internalisation is dependent on conventional PKC isoforms; (ii) microtubules transport internalised half desmosomes to the region of the centrosome by a kinesin-dependent mechanism; (iii) desmosomal proteins remain colocalised after internalisation and are not recycled to the cell surface; (iv) internalised desmosomes are degraded by the combined action of lysosomes and proteasomes. We also confirm that half desmosome internalisation is dependent upon the actin cytoskeleton. These results suggest that half desmosomes are not disassembled and recycled during or after internalisation but instead are transported to the centrosomal region where they are degraded. These findings may have significance for the down-regulation of desmosomes in wounds. PMID:25291180

Antigen presenting cells costimulatory signaling during pre-implantation pregnancy 

Directory of Open Access Journals (Sweden)

Anna Sławek

2012-09-01

Full Text Available  Success of pregnancy depends on many factors. Three phenomena inducing immune tolerance against semi-allogeneic conceptus may play a crucial role in the pre-implantation period of pregnancy: influence of sex hormones in sex cycle, presence of oocyte or embryo and the presence of semen in the female reproductive tract. On the other hand dendritic cells are the most effective antigen-presenting cells in regulation of immune phenomena and also are considered as potent participants in inducing immune tolerance in the pregnancy. They communicate with T cells in cell contact-dependent manner or via cytokines. During cell-cell contacts, costimulatory molecules play a key role and their expression is often dependent on cytokines milieu. Both costimulatory molecules and cytokines influence generation of T regulatory cells. Interactions of these molecules are closely related. In this paper we would like to pay attention to the importance of antigen presenting cells costimulatory potency in immune regulation during a pre-implantation period of pregnancy.

A novel and effective cancer immunotherapy mouse model using antigen-specific B cells selected in vitro.

Directory of Open Access Journals (Sweden)

Tatsuya Moutai

Full Text Available Immunotherapies such as adoptive transfer of T cells or natural killer cells, or monoclonal antibody (MoAb treatment have recently been recognized as effective means to treat cancer patients. However, adoptive transfer of B cells or plasma cells producing tumor-specific antibodies has not been applied as a therapy because long-term culture and selective expansion of antigen-specific B cells has been technically very difficult. Here, we describe a novel cancer immunotherapy that uses B-cell adoptive transfer. We demonstrate that germinal-center-like B cells (iGB cells induced in vitro from mouse naïve B cells become plasma cells and produce IgG antibodies for more than a month in the bone marrow of non-irradiated recipient mice. When transferred into mice, iGB cells producing antibody against a surrogate tumor antigen suppressed lung metastasis and growth of mouse melanoma cells expressing the same antigen and prolonged survival of the recipients. In addition, we have developed a novel culture system called FAIS to selectively expand antigen-specific iGB cells utilizing the fact that iGB cells are sensitive to Fas-induced cell death unless their antigen receptors are ligated by membrane-bound antigens. The selected iGB cells efficiently suppressed lung metastasis of melanoma cells in the adoptive immunotherapy model. As human blood B cells can be propagated as iGB cells using culture conditions similar to the mouse iGB cell cultures, our data suggest that it will be possible to treat cancer-bearing patients by the adoptive transfer of cancer-antigen-specific iGB cells selected in vitro. This new adoptive immunotherapy should be an alternative to the laborious development of MoAb drugs against cancers for which no effective treatments currently exist.

Paired Expression Analysis of Tumor Cell Surface Antigens

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Rimas J. Orentas

2017-08-01

Full Text Available Adoptive immunotherapy with antibody-based therapy or with T cells transduced to express chimeric antigen receptors (CARs is useful to the extent that the cell surface membrane protein being targeted is not expressed on normal tissues. The most successful CAR-based (anti-CD19 or antibody-based therapy (anti-CD20 in hematologic malignancies has the side effect of eliminating the normal B cell compartment. Targeting solid tumors may not provide a similar expendable marker. Beyond antibody to Her2/NEU and EGFR, very few antibody-based and no CAR-based therapies have seen broad clinical application for solid tumors. To expand the way in which the surfaceome of solid tumors can be analyzed, we created an algorithm that defines the pairwise relative overexpression of surface antigens. This enables the development of specific immunotherapies that require the expression of two discrete antigens on the surface of the tumor target. This dyad analysis was facilitated by employing the Hotelling’s T-squared test (Hotelling–Lawley multivariate analysis of variance for two independent variables in comparison to a third constant entity (i.e., gene expression levels in normal tissues. We also present a unique consensus scoring mechanism for identifying transcripts that encode cell surface proteins. The unique application of our bioinformatics processing pipeline and statistical tools allowed us to compare the expression of two membrane protein targets as a pair, and to propose a new strategy based on implementing immunotherapies that require both antigens to be expressed on the tumor cell surface to trigger therapeutic effector mechanisms. Specifically, we found that, for MYCN amplified neuroblastoma, pairwise expression of ACVR2B or anaplastic lymphoma kinase (ALK with GFRA3, GFRA2, Cadherin 24, or with one another provided the strongest hits. For MYCN, non-amplified stage 4 neuroblastoma, neurotrophic tyrosine kinase 1, or ALK paired with GFRA2, GFRA3, SSK

Prostate tumor-derived exosomes down-regulate NKG2D expression on natural killer cells and CD8+ T cells: mechanism of immune evasion.

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Marie Lundholm

Full Text Available Tumor-derived exosomes, which are nanometer-sized extracellular vesicles of endosomal origin, have emerged as promoters of tumor immune evasion but their role in prostate cancer (PC progression is poorly understood. In this study, we investigated the ability of prostate tumor-derived exosomes to downregulate NKG2D expression on natural killer (NK and CD8+ T cells. NKG2D is an activating cytotoxicity receptor whose aberrant loss in cancer plays an important role in immune suppression. Using flow cytometry, we found that exosomes produced by human PC cells express ligands for NKG2D on their surface. The NKG2D ligand-expressing prostate tumor-derived exosomes selectively induced downregulation of NKG2D on NK and CD8+ T cells in a dose-dependent manner, leading to impaired cytotoxic function in vitro. Consistent with these findings, patients with castration-resistant PC (CRPC showed a significant decrease in surface NKG2D expression on circulating NK and CD8+ T cells compared to healthy individuals. Tumor-derived exosomes are likely involved in this NKG2D downregulation, since incubation of healthy lymphocytes with exosomes isolated from serum or plasma of CRPC patients triggered downregulation of NKG2D expression in effector lymphocytes. These data suggest prostate tumor-derived exosomes as down-regulators of the NKG2D-mediated cytotoxic response in PC patients, thus promoting immune suppression and tumor escape.

Effect of radiation on the expression of tumor-associated antigens of human lung adenocarcinoma cells. Immunological study using monoclonal antibodies

Energy Technology Data Exchange (ETDEWEB)

Hareyama, Masato

1988-12-01

We studied the effects of irradiation on the expression of a tumor-associated antigen (YH206 antigen) of cultured human lung adenocarcinoma A549 cells by using enzyme-linked immunosorbent assay (ELISA) and flow cytometry. YH206 antigen is preferentially expressed on adenocarcinoma cells. Irradiation of A549 cells remarkably increased the expression of YH206 antigen on the cell surface and the level of the antigen in the culture supernatant as well as in the cell lysate, whereas it significantly affected the expression of HLA (MHC-class I) antigen on the same cells. The expression of HLA antigen on the cell was also increased after treatment of the cells with interferon-..gamma... In an additional experiment, cells were stained simultaneously for surface antigens (fluorescein coupled antibodies) and for DNA content (propidium iodide), and then dual parameter measurements were performed by flow cytometry to analyse the relationship between antigen levels and the cell cycle. YH206 antigen and HLA antigen increased more in the S and G/sub 2//M phases of the cell cycle than in G/sub 0//G/sub 1/. The expression of YH206 antigen was enhanced in the S and G/sub 2//M phases by irradiation, whereas the expression of HLA antigen was enhanced in each phase of the cell cycle with irradiation or IFN. These results suggest that irradiation plays a key role in the change of the expression of certain tumor-associated antigens.

Downregulation of Connective Tissue Growth Factor by Three-Dimensional Matrix Enhances Ovarian Carcinoma Cell Invasion

Science.gov (United States)

Barbolina, Maria V.; Adley, Brian P.; Kelly, David L.; Shepard, Jaclyn; Fought, Angela J.; Scholtens, Denise; Penzes, Peter; Shea, Lonnie D.; Sharon Stack, M

2010-01-01

Epithelial ovarian carcinoma (EOC) is a leading cause of death from gynecologic malignancy, due mainly to the prevalence of undetected metastatic disease. The process of cell invasion during intra-peritoneal anchoring of metastatic lesions requires concerted regulation of many processes, including modulation of adhesion to the extracellular matrix and localized invasion. Exploratory cDNA microarray analysis of early response genes (altered after 4 hours of 3-dimensional collagen culture) coupled with confirmatory real-time RT-PCR, multiple three-dimensional cell culture matrices, Western blot, immunostaining, adhesion, migration, and invasion assays were used to identify modulators of adhesion pertinent to EOC progression and metastasis. cDNA microarray analysis indicated a dramatic downregulation of connective tissue growth factor (CTGF) in EOC cells placed in invasion-mimicking conditions (3-dimensional type I collagen). Examination of human EOC specimens revealed that CTGF expression was absent in 46% of the tested samples (n=41), but was present in 100% of normal ovarian epithelium samples (n=7). Reduced CTGF expression occurs in many types of cells and may be a general phenomenon displayed by cells encountering a 3D environment. CTGF levels were inversely correlated with invasion such that downregulation of CTGF increased, while its upregulation reduced, collagen invasion. Cells adhered preferentially to a surface comprised of both collagen I and CTGF relative to either component alone using α6β1 and α3β1 integrins. Together these data suggest that downregulation of CTGF in EOC cells may be important for cell invasion through modulation of cell-matrix adhesion. PMID:19382180

In Vitro Evidence of the Presence of Mesenchymal Stromal Cells in Cervical Cancer and Their Role in Protecting Cancer Cells from Cytotoxic T Cell Activity

Science.gov (United States)

Montesinos, Juan J.; Mora-García, María de L.; Mayani, Héctor; Flores-Figueroa, Eugenia; García-Rocha, Rosario; Fajardo-Orduña, Guadalupe R.; Castro-Manrreza, Marta E.; Weiss-Steider, Benny

2013-01-01

Mesenchymal stromal cells (MSCs) have been isolated from different tumors and it has been suggested that they support tumor growth through immunosuppression processes that favor tumor cell evasion from the immune system. To date, however, the presence of MSCs in cervical cancer (CeCa) and their possible role in tumor growth remains unknown. Herein we report on the presence of MSCs in cervical tissue, both in normal conditions (NCx-MSCs) and in CeCa (CeCa-MSCs), and described several biological properties of such cells. Our study showed similar patterns of cell surface antigen expression, but distinct differentiation potentials, when we compared both cervical MSC populations to MSCs from normal bone marrow (BM-MSCs, the gold standard). Interestingly, CeCa-MSCs were negative for the presence of human papiloma virus, indicating that these cells are not infected by such a viral agent. Also, interestingly, and in contrast to NCx-MSCs, CeCa-MSCs induced significant downregulation of surface HLA class I molecules (HLA-A*0201) on CaSki cells and other CeCa cell lines. We further observed that CeCa-MSCs inhibited antigen-specific T cell recognition of CaSki cells by cytotoxic T lymphocytes (CTLs). HLA class I downregulation on CeCa cells correlated with the production of IL-10 in cell cocultures. Importantly, this cytokine strongly suppressed recognition of CeCa cells by CTLs. In summary, this study demonstrates the presence of MSCs in CeCa and suggests that tumor-derived MSCs may provide immune protection to tumor cells by inducing downregulation of HLA class I molecules. This mechanism may have important implications in tumor growth. PMID:23656504

Chimeric Antigen Receptor-Engineered T Cells for Immunotherapy of Cancer

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Marc Cartellieri

2010-01-01

Full Text Available CD4+ and CD8+ T lymphocytes are powerful components of adaptive immunity, which essentially contribute to the elimination of tumors. Due to their cytotoxic capacity, T cells emerged as attractive candidates for specific immunotherapy of cancer. A promising approach is the genetic modification of T cells with chimeric antigen receptors (CARs. First generation CARs consist of a binding moiety specifically recognizing a tumor cell surface antigen and a lymphocyte activating signaling chain. The CAR-mediated recognition induces cytokine production and tumor-directed cytotoxicity of T cells. Second and third generation CARs include signal sequences from various costimulatory molecules resulting in enhanced T-cell persistence and sustained antitumor reaction. Clinical trials revealed that the adoptive transfer of T cells engineered with first generation CARs represents a feasible concept for the induction of clinical responses in some tumor patients. However, further improvement is required, which may be achieved by second or third generation CAR-engrafted T cells.

Human Invariant Natural Killer T Cells Respond to Antigen-Presenting Cells Exposed to Lipids from Olea europaea Pollen.

Science.gov (United States)

Abos Gracia, Beatriz; López Relaño, Juan; Revilla, Ana; Castro, Lourdes; Villalba, Mayte; Martín Adrados, Beatriz; Regueiro, Jose Ramon; Fernández-Malavé, Edgar; Martínez Naves, Eduardo; Gómez Del Moral, Manuel

2017-01-01

Allergic sensitization might be influenced by the lipids present in allergens, which can be recognized by natural killer T (NKT) cells on antigen-presenting cells (APCs). The aim of this study was to analyze the effect of olive pollen lipids in human APCs, including monocytes as well as monocyte-derived macrophages (Mϕ) and dendritic cells (DCs). Lipids were extracted from olive (Olea europaea) pollen grains. Invariant (i)NKT cells, monocytes, Mϕ, and DCs were obtained from buffy coats of healthy blood donors, and their cell phenotype was determined by flow cytometry. iNKT cytotoxicity was measured using a lactate dehydrogenase assay. Gene expression of CD1A and CD1D was performed by RT-PCR, and the production of IL-6, IL-10, IL-12, and TNF-α cytokines by monocytes, Mϕ, and DCs was measured by ELISA. Our results showed that monocytes and monocyte-derived Mϕ treated with olive pollen lipids strongly activate iNKT cells. We observed several phenotypic modifications in the APCs upon exposure to pollen-derived lipids. Both Mϕ and monocytes treated with olive pollen lipids showed an increase in CD1D gene expression, whereas upregulation of cell surface CD1d protein occurred only in Mϕ. Furthermore, DCs differentiated in the presence of human serum enhance their surface CD1d expression when exposed to olive pollen lipids. Finally, olive pollen lipids were able to stimulate the production of IL-6 but downregulated the production of lipopolysaccharide- induced IL-10 by Mϕ. Olive pollen lipids alter the phenotype of monocytes, Mϕ, and DCs, resulting in the activation of NKT cells, which have the potential to influence allergic immune responses. © 2017 S. Karger AG, Basel.

Modeled microgravity suppressed invasion and migration of human glioblastoma U87 cells through downregulating store-operated calcium entry

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Shi, Zi-xuan [Department of Traditional Chinese Medicine, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Rao, Wei [Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Wang, Huan [Department of Dermatology, Tangdu Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Wang, Nan-ding [Department of Cardiology, Xi' an Traditional Chinese Medicine Hospital, Xi' an, 710032 (China); Si, Jing-Wen; Zhao, Jiao; Li, Jun-chang [Department of Traditional Chinese Medicine, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Wang, Zong-ren, E-mail: zongren@fmmu.edu.cn [Department of Traditional Chinese Medicine, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China)

2015-02-13

Glioblastoma is the most common brain tumor and is characterized with robust invasion and migration potential resulting in poor prognosis. Previous investigations have demonstrated that modeled microgravity (MMG) could decline the cell proliferation and attenuate the metastasis potential in several cell lines. In this study, we studied the effects of MMG on the invasion and migration potentials of glioblastoma in human glioblastoma U87 cells. We found that MMG stimulation significantly attenuated the invasion and migration potentials, decreased thapsigargin (TG) induced store-operated calcium entry (SOCE) and downregulated the expression of Orai1 in U87 cells. Inhibition of SOCE by 2-APB or stromal interaction molecule 1 (STIM1) downregulation both mimicked the effects of MMG on the invasion and migration potentials in U87 cells. Furthermore, upregulation of Orai1 significantly weakened the effects of MMG on the invasion and migration potentials in U87 cells. Therefore, these findings indicated that MMG stimulation inhibited the invasion and migration potentials of U87 cells by downregulating the expression of Orai1 and sequentially decreasing the SOCE, suggesting that MMG might be a new potential therapeutic strategy in glioblastoma treatment in the future. - Highlights: • Modeled microgravity (MMG) suppressed migration and invasion in U87 cells. • MMG downregulated the SOCE and the expression of Orai1. • SOCE inhibition mimicked the effects of MMG on migration and invasion potentials. • Restoration of SOCE diminished the effects of MMG on migration and invasion.

Modeled microgravity suppressed invasion and migration of human glioblastoma U87 cells through downregulating store-operated calcium entry

International Nuclear Information System (INIS)

Shi, Zi-xuan; Rao, Wei; Wang, Huan; Wang, Nan-ding; Si, Jing-Wen; Zhao, Jiao; Li, Jun-chang; Wang, Zong-ren

2015-01-01

Glioblastoma is the most common brain tumor and is characterized with robust invasion and migration potential resulting in poor prognosis. Previous investigations have demonstrated that modeled microgravity (MMG) could decline the cell proliferation and attenuate the metastasis potential in several cell lines. In this study, we studied the effects of MMG on the invasion and migration potentials of glioblastoma in human glioblastoma U87 cells. We found that MMG stimulation significantly attenuated the invasion and migration potentials, decreased thapsigargin (TG) induced store-operated calcium entry (SOCE) and downregulated the expression of Orai1 in U87 cells. Inhibition of SOCE by 2-APB or stromal interaction molecule 1 (STIM1) downregulation both mimicked the effects of MMG on the invasion and migration potentials in U87 cells. Furthermore, upregulation of Orai1 significantly weakened the effects of MMG on the invasion and migration potentials in U87 cells. Therefore, these findings indicated that MMG stimulation inhibited the invasion and migration potentials of U87 cells by downregulating the expression of Orai1 and sequentially decreasing the SOCE, suggesting that MMG might be a new potential therapeutic strategy in glioblastoma treatment in the future. - Highlights: • Modeled microgravity (MMG) suppressed migration and invasion in U87 cells. • MMG downregulated the SOCE and the expression of Orai1. • SOCE inhibition mimicked the effects of MMG on migration and invasion potentials. • Restoration of SOCE diminished the effects of MMG on migration and invasion

Dichotomy of the human T cell response to Leishmania antigens. I. Th1-like response to Leishmania major promastigote antigens in individuals recovered from cutaneous leishmaniasis

DEFF Research Database (Denmark)

Kemp, M; Hey, A S; Kurtzhals, J A

1994-01-01

of skin lesions, and in Danes without known exposure to Leishmania parasites. Proliferation and production of interferon-gamma (IFN-gamma) and IL-4 in antigen-stimulated cultures was measured. Lymphocytes from individuals with a history of CL proliferated vigorously and produced IFN-gamma after...... the unexposed Danes were not activated by gp63. The cells from Danish donors produced either IFN-gamma or IL-4, but not both cytokines after incubation with the crude preparation of L. major antigens. The data show that the T cell response to Leishmania antigens in humans who have had uncomplicated CL...... stimulation with either a crude preparation of L. major antigens or the major surface protease gp63. These cultures produced no or only little IL-4. Also cells from leishmanin skin test-positive donors with no history of CL produced IFN-gamma and no IL-4 in response to L. major antigens. Cells from...

Flow Cytometric Analysis of T, B, and NK Cells Antigens in Patients with Mycosis Fungoides

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Serkan Yazıcı

2015-01-01

Full Text Available We retrospectively analyzed the clinicopathological correlation and prognostic value of cell surface antigens expressed by peripheral blood mononuclear cells in patients with mycosis fungoides (MF. 121 consecutive MF patients were included in this study. All patients had peripheral blood flow cytometry as part of their first visit. TNMB and histopathological staging of the cases were retrospectively performed in accordance with International Society for Cutaneous Lymphomas/European Organization of Research and Treatment of Cancer (ISCL/EORTC criteria at the time of flow cytometry sampling. To determine prognostic value of cell surface antigens, cases were divided into two groups as stable and progressive disease. 17 flow cytometric analyses of 17 parapsoriasis (PP and 11 analyses of 11 benign erythrodermic patients were included as control groups. Fluorescent labeled monoclonal antibodies were used to detect cell surface antigens: T cells (CD3+, CD4+, CD8+, TCRαβ+, TCRγδ+, CD7+, CD4+CD7+, CD4+CD7−, and CD71+, B cells (HLA-DR+, CD19+, and HLA-DR+CD19+, NKT cells (CD3+CD16+CD56+, and NK cells (CD3−CD16+CD56+. The mean value of all cell surface antigens was not statistically significant between parapsoriasis and MF groups. Along with an increase in cases of MF stage statistically significant difference was found between the mean values of cell surface antigens. Flow cytometric analysis of peripheral blood cell surface antigens in patients with mycosis fungoides may contribute to predicting disease stage and progression.

Dissection and manipulation of antigen-specific T cell responses

NARCIS (Netherlands)

Schepers, Koen

2006-01-01

T cells recognize pathogen-derived antigens and are crucial for fighting pathogens such as viruses and bacteria. In addition, T cells are able to recognize and attack certain types of tumors, in particular virally induced tumors. In this thesis we aimed 1) to obtain more insight into

Robust and Accurate Discrimination of Self/Non-Self Antigen Presentations by Regulatory T Cell Suppression.

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Chikara Furusawa

Full Text Available The immune response by T cells usually discriminates self and non-self antigens, even though the negative selection of self-reactive T cells is imperfect and a certain fraction of T cells can respond to self-antigens. In this study, we construct a simple mathematical model of T cell populations to analyze how such self/non-self discrimination is possible. The results demonstrate that the control of the immune response by regulatory T cells enables a robust and accurate discrimination of self and non-self antigens, even when there is a significant overlap between the affinity distribution of T cells to self and non-self antigens. Here, the number of regulatory T cells in the system acts as a global variable controlling the T cell population dynamics. The present study provides a basis for the development of a quantitative theory for self and non-self discrimination in the immune system and a possible strategy for its experimental verification.

Robust and Accurate Discrimination of Self/Non-Self Antigen Presentations by Regulatory T Cell Suppression.

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Furusawa, Chikara; Yamaguchi, Tomoyuki

The immune response by T cells usually discriminates self and non-self antigens, even though the negative selection of self-reactive T cells is imperfect and a certain fraction of T cells can respond to self-antigens. In this study, we construct a simple mathematical model of T cell populations to analyze how such self/non-self discrimination is possible. The results demonstrate that the control of the immune response by regulatory T cells enables a robust and accurate discrimination of self and non-self antigens, even when there is a significant overlap between the affinity distribution of T cells to self and non-self antigens. Here, the number of regulatory T cells in the system acts as a global variable controlling the T cell population dynamics. The present study provides a basis for the development of a quantitative theory for self and non-self discrimination in the immune system and a possible strategy for its experimental verification.

Downregulation of tight junction-associated MARVEL protein marvelD3 during epithelial-mesenchymal transition in human pancreatic cancer cells.

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Kojima, Takashi; Takasawa, Akira; Kyuno, Daisuke; Ito, Tatsuya; Yamaguchi, Hiroshi; Hirata, Koichi; Tsujiwaki, Mitsuhiro; Murata, Masaki; Tanaka, Satoshi; Sawada, Norimasa

2011-10-01

The novel tight junction protein marvelD3 contains a conserved MARVEL (MAL and related proteins for vesicle trafficking and membrane link) domain like occludin and tricellulin. However, little is yet known about the detailed role and regulation of marvelD3 in normal epithelial cells and cancer cells, including pancreatic cancer. In the present study, we investigated marvelD3 expression in well and poorly differentiated human pancreatic cancer cell lines and normal pancreatic duct epithelial cells in which the hTERT gene was introduced into human pancreatic duct epithelial cells in primary culture, and the changes of marvelD3 during Snail-induced epithelial-mesenchymal transition (EMT) under hypoxia, TGF-β treatment and knockdown of FOXA2 in well differentiated pancreatic cancer HPAC cells. MarvelD3 was transcriptionally downregulated in poorly differentiated pancreatic cancer cells and during Snail-induced EMT of pancreatic cancer cells in which Snail was highly expressed and the fence function downregulated, whereas it was maintained in well differentiated human pancreatic cancer cells and normal pancreatic duct epithelial cells. Depletion of marvelD3 by siRNAs in HPAC cells resulted in downregulation of barrier functions indicated as a decrease in transepithelial electric resistance and an increase of permeability to fluorescent dextran tracers, whereas it did not affect fence function of tight junctions. In conclusion, marvelD3 is transcriptionally downregulated in Snail-induced EMT during the progression for the pancreatic cancer. Copyright © 2011 Elsevier Inc. All rights reserved.

Functional antigen binding by the defective B cells of CBA/N mice.

Science.gov (United States)

Snippe, H; Merchant, B; Lizzio, E F; Inman, J K

1982-01-01

CBA/N mice have an X-linked B cell defect which prevents them from responding to nonmitogenic thymic independent (TI-2) antigens such as dinitrophenylated DNP-Ficoll (1,2). The F1 male progeny of CBA/N female mice express the same defect. Spleen cell suspensions from such defective mice (CBA/N X C3H/HeN F1 males) could not respond to DNP-Ficoll following in vitro immunization and subsequent transfer into irradiated, syngeneic, F1 male recipients as expected. In contrast, normal CBA/N X C3H/HeN F1 female spleen cells could respond and effect a "rescue"; they mounted strong plaque-forming cell responses 7 days after in vitro exposure to DNP-Ficoll and subsequent transfer into irradiated F1 male recipients. Defective F1 male spleen cells, however, could bind significant quantities of 125I-DNP-Ficoll after in vitro exposure. Extensive washing of these spleen cells could not reverse this binding. Such DNP-Ficoll-exposed and washed F1 male spleen cells could, after transfer, aid normal untreated F1 female cells in their rescue function. The defective F1 male spleen cells could convey immunogenic quantities of DNP-Ficoll to the "rescuing" F1 female cells. Mitomycin treatment of F1 male cells did not interfere with their conveyor function. Goat anti-mouse mu serum impeded the passive antigen conveyor function of defective F1 male cells as did prior exposure to high concentrations of free DNP hapten. Our data support the view that the B cell defect of CBA/N X C3H/HeN F1 male mice does not relate to antigen binding, but rather to an inability to be effectively triggered by certain cell-bound polymeric antigens.

Lactogenic differentiation of HC11 cells is not accompanied by downregulation of AP-2 transcription factor genes

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Schorle Hubert

2008-06-01

Full Text Available Abstract Background During pregnancy the mammary epithelium undergoes a complex developmental process which culminates in the generation of the milk-secreting epithelium. Secretory epithelial cells display lactogenic differentiation which is characterized by the expression of milk protein genes, such as beta-casein or whey acidic protein (WAP. Transcription factors AP-2alpha and AP-2gamma are downregulated during lactation, and their overexpression in transgenic mice impaired the secretory differentiation of the mammary epithelium, resulting in lactation failure. To explore whether the downregulation of AP-2alpha and AP-2gamma is of functional significance for lactogenic differentiation, we analyzed the expression of the AP-2 family members during the lactogenic differentiation of HC11 mammary epithelial cells in vitro. Differentiation of HC11 cells was induced following established protocols by applying the lactogenic hormones prolactin, dexamethasone and insulin. Findings HC11 cells express all AP-2 family members except AP-2delta. Using RT-PCR we could not detect a downregulation of any of these genes during the lactogenic differentiation of HC11 cells in vitro. This finding was confirmed for AP-2alpha and AP-2gamma using Northern analysis. Differentiating HC11 cells displayed lower expression levels of milk protein genes than mammary glands of mid-pregnant or lactating mice. Conclusion The extent of lactogenic differentiation of HC11 cells in vitro is limited compared to mammary epithelium undergoing secretory differentiation in vivo. Downregulation of AP-2 transcription factor genes is not required for lactogenic differentiation of HC11 cells but may functionally be involved in aspects of lactogenic differentiation in vivo that are not reflected by the HC11 system.

Distinction of the memory B cell response to cognate antigen versus bystander inflammatory signals.

Science.gov (United States)

Benson, Micah J; Elgueta, Raul; Schpero, William; Molloy, Michael; Zhang, Weijun; Usherwood, Edward; Noelle, Randolph J

2009-08-31

The hypothesis that bystander inflammatory signals promote memory B cell (B(MEM)) self-renewal and differentiation in an antigen-independent manner is critically evaluated herein. To comprehensively address this hypothesis, a detailed analysis is presented examining the response profiles of B-2 lineage B220(+)IgG(+) B(MEM) toward cognate protein antigen in comparison to bystander inflammatory signals. After in vivo antigen encounter, quiescent B(MEM) clonally expand. Surprisingly, proliferating B(MEM) do not acquire germinal center (GC) B cell markers before generating daughter B(MEM) and differentiating into plasma cells or form structurally identifiable GCs. In striking contrast to cognate antigen, inflammatory stimuli, including Toll-like receptor agonists or bystander T cell activation, fail to induce even low levels of B(MEM) proliferation or differentiation in vivo. Under the extreme conditions of adjuvanted protein vaccination or acute viral infection, no detectable bystander proliferation or differentiation of B(MEM) occurred. The absence of a B(MEM) response to nonspecific inflammatory signals clearly shows that B(MEM) proliferation and differentiation is a process tightly controlled by the availability of cognate antigen.

Cholesterol Down-Regulates BK Channels Stably Expressed in HEK 293 Cells

Science.gov (United States)

Deng, Xiu-Ling; Sun, Hai-Ying; Li, Gui-Rong

2013-01-01

Cholesterol is one of the major lipid components of the plasma membrane in mammalian cells and is involved in the regulation of a number of ion channels. The present study investigates how large conductance Ca2+-activated K+ (BK) channels are regulated by membrane cholesterol in BK-HEK 293 cells expressing both the α-subunit hKCa1.1 and the auxiliary β1-subunit or in hKCa1.1-HEK 293 cells expressing only the α-subunit hKCa1.1 using approaches of electrophysiology, molecular biology, and immunocytochemistry. Membrane cholesterol was depleted in these cells with methyl-β-cyclodextrin (MβCD), and enriched with cholesterol-saturated MβCD (MβCD-cholesterol) or low-density lipoprotein (LDL). We found that BK current density was decreased by cholesterol enrichment in BK-HEK 293 cells, with a reduced expression of KCa1.1 protein, but not the β1-subunit protein. This effect was fully countered by the proteasome inhibitor lactacystin or the lysosome function inhibitor bafilomycin A1. Interestingly, in hKCa1.1-HEK 293 cells, the current density was not affected by cholesterol enrichment, but directly decreased by MβCD, suggesting that the down-regulation of BK channels by cholesterol depends on the auxiliary β1-subunit. The reduced KCa1.1 channel protein expression was also observed in cultured human coronary artery smooth muscle cells with cholesterol enrichment using MβCD-cholesterol or LDL. These results demonstrate the novel information that cholesterol down-regulates BK channels by reducing KCa1.1 protein expression via increasing the channel protein degradation, and the effect is dependent on the auxiliary β1-subunit. PMID:24260325

Exosomes derived from tumor cells genetically modified to express Mycobacterium tuberculosis antigen: a novel vaccine for cancer therapy.

Science.gov (United States)

Koyama, Yoshiyuki; Ito, Tomoko; Hasegawa, Aya; Eriguchi, Masazumi; Inaba, Toshio; Ushigusa, Takahiro; Sugiura, Kikuya

2016-11-01

To examine the potential of exosomes derived from the tumor cells, which had been genetically modified to express a Mycobacterium tuberculosis antigen, as a cancer vaccine aimed at overcoming the weak immunogenicity of tumor antigens. We transfected B16 melanoma cells with a plasmid encoding the M. tuberculosis antigen, early secretory antigenic target-6 (ESAT-6). The secreted exosomes bearing both tumor-associated antigens and the pathogenic antigen (or their epitopes) were collected. When the exosomes were injected into foot pads of mice, they significantly (p exosomes significantly suppressed (p exosomes derived from the non-transfected B16 cells showed no effect on tumor growth, although both exosomes should have similar tumor antigens. Exosomes bearing both tumor antigens and the M. tuberculosis antigen (or their epitopes) have a high potential as a candidate for cancer vaccine to overcome the immune escape by tumor cells.

Enhanced Dendritic Cell-Mediated Antigen-Specific CD4+ T Cell Responses: IFN-Gamma Aids TLR Stimulation

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Kuo-Ching Sheng

2013-01-01

Full Text Available Phenotypic maturation and T cell stimulation are two functional attributes of DCs critical for immune induction. The combination of antigens, including those from cancer, with Toll-like receptor (TLR ligands induces far superior cellular immune responses compared to antigen alone. In this study, IFN-gamma treatment of bone marrow-derived DC, followed by incubation with the TLR2, TLR4, or TLR9 agonists, enhanced DC activation compared to TLR ligation alone. Most notably, the upregulation of CD40 with LPS stimulation and CD86 with CpG stimulation was observed in in vitro cultures. Similarly, IFN-gamma coinjected with TLR ligands was able to promote DC activation in vivo, with DCs migrating from the site of immunization to the popliteal lymph nodes demonstrating increased expression of CD80 and CD86. The heightened DC activation translated to a drastic increase in T cell stimulatory capacity in both antigen independent and antigen dependent fashions. This is the first time that IFN-gamma has been shown to have a combined effect with TLR ligation to enhance DC activation and function. The results demonstrate the novel use of IFN-gamma together with TLR agonists to enhance antigen-specific T cell responses, for applications in the development of enhanced vaccines and drug targets against diseases including cancer.

The Hsc/Hsp70 co-chaperone network controls antigen aggregation and presentation during maturation of professional antigen presenting cells.

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Nadja Kettern

Full Text Available The maturation of mouse macrophages and dendritic cells involves the transient deposition of ubiquitylated proteins in the form of dendritic cell aggresome-like induced structures (DALIS. Transient DALIS formation was used here as a paradigm to study how mammalian cells influence the formation and disassembly of protein aggregates through alterations of their proteostasis machinery. Co-chaperones that modulate the interplay of Hsc70 and Hsp70 with the ubiquitin-proteasome system (UPS and the autophagosome-lysosome pathway emerged as key regulators of this process. The chaperone-associated ubiquitin ligase CHIP and the ubiquitin-domain protein BAG-1 are essential for DALIS formation in mouse macrophages and bone-marrow derived dendritic cells (BMDCs. CHIP also cooperates with BAG-3 and the autophagic ubiquitin adaptor p62 in the clearance of DALIS through chaperone-assisted selective autophagy (CASA. On the other hand, the co-chaperone HspBP1 inhibits the activity of CHIP and thereby attenuates antigen sequestration. Through a modulation of DALIS formation CHIP, BAG-1 and HspBP1 alter MHC class I mediated antigen presentation in mouse BMDCs. Our data show that the Hsc/Hsp70 co-chaperone network controls transient protein aggregation during maturation of professional antigen presenting cells and in this way regulates the immune response. Similar mechanisms may modulate the formation of aggresomes and aggresome-like induced structures (ALIS in other mammalian cell types.

Antisense downregulation of mutant huntingtin in a cell model

DEFF Research Database (Denmark)

Hasholt, L.; Abell, K.; Norremolle, A.

2003-01-01

or by addition to the culture medium. Results Expression of the fusion protein containing the mutant huntingtin fragment resulted in diffuse green fluorescence in the cytoplasm and formation of aggregates in some of the NT2 cells and NT2-N neurons. We obtained antisense sequence-specific inhibition of expression...... of the fusion protein and/or suppression of the aggregate formation in both cell types. In the NT2 cells the antisense effect was dependent on the way of administration of the oligo. Conclusions The PS-antisense oligo is effective in downregulation of mutant huntingtin, and the reduction of aggregate formation...... is a sensitive biological marker. The findings suggest that antisense knockdown of huntingtin could be a useful strategy for treatment of HD, and could also be suitable for studies of the normal and pathological function of huntingtin in different cellular model systems....

Survival and antigenic profile of irradiated malarial sporozoites in infected liver cells

International Nuclear Information System (INIS)

Suhrbier, A.; Winger, L.A.; Castellano, E.; Sinden, R.E.

1990-01-01

Exoerythrocytic (EE) stages of Plasmodium berghei derived from irradiated sporozoites were cultured in vitro in HepG2 cells. They synthesized several antigens, predominantly but not exclusively those expressed by normal early erythrocytic schizonts. After invasion, over half the intracellular sporozoites, both normal and irradiated, appeared to die. After 24 h, in marked contrast to the normal parasites, EE parasites derived from irradiated sporozoites continued to break open, shedding their antigens into the cytoplasm of the infected host cells. Increasing radiation dosage, which has previously been shown to reduce the ability of irradiated sporozoites to protect animals, correlated with reduced de novo antigen synthesis by EE parasites derived from irradiated sporozoites

mRNA-binding protein TIA-1 reduces cytokine expression in human endometrial stromal cells and is down-regulated in ectopic endometrium.

Science.gov (United States)

Karalok, Hakan Mete; Aydin, Ebru; Saglam, Ozlen; Torun, Aysenur; Guzeloglu-Kayisli, Ozlem; Lalioti, Maria D; Kristiansson, Helena; Duke, Cindy M P; Choe, Gina; Flannery, Clare; Kallen, Caleb B; Seli, Emre

2014-12-01

Cytokines and growth factors play important roles in endometrial function and the pathogenesis of endometriosis. mRNAs encoding cytokines and growth factors undergo rapid turnover; primarily mediated by adenosine- and uridine-rich elements (AREs) located in their 3'-untranslated regions. T-cell intracellular antigen (TIA-1), an mRNA-binding protein, binds to AREs in target transcripts, leading to decreased gene expression. The purpose of this article was to determine whether TIA-1 plays a role in the regulation of endometrial cytokine and growth factor expression during the normal menstrual cycle and whether TIA-1 expression is altered in women with endometriosis. Eutopic endometrial tissue obtained from women without endometriosis (n = 30) and eutopic and ectopic endometrial tissues from women with endometriosis (n = 17) were immunostained for TIA-1. Staining intensities were evaluated by histological scores (HSCOREs). The regulation of endometrial TIA-1 expression by immune factors and steroid hormones was studied by treating primary cultured human endometrial stromal cells (HESCs) with vehicle, lipopolysaccharide, TNF-α, IL-6, estradiol, or progesterone, followed by protein blot analyses. HESCs were engineered to over- or underexpress TIA-1 to test whether TIA-1 regulates IL-6 or TNF-α expression in these cells. We found that TIA-1 is expressed in endometrial stromal and glandular cells throughout the menstrual cycle and that this expression is significantly higher in the perimenstrual phase. In women with endometriosis, TIA-1 expression in eutopic and ectopic endometrium was reduced compared with TIA-1 expression in eutopic endometrium of unaffected control women. Lipopolysaccharide and TNF-α increased TIA-1 expression in HESCs in vitro, whereas IL-6 or steroid hormones had no effect. In HESCs, down-regulation of TIA-1 resulted in elevated IL-6 and TNF-α expression, whereas TIA-1 overexpression resulted in decreased IL-6 and TNF-α expression. Endometrial

Highly efficient gene transfer using a retroviral vector into murine T cells for preclinical chimeric antigen receptor-expressing T cell therapy

International Nuclear Information System (INIS)

Kusabuka, Hotaka; Fujiwara, Kento; Tokunaga, Yusuke; Hirobe, Sachiko; Nakagawa, Shinsaku; Okada, Naoki

2016-01-01

Adoptive immunotherapy using chimeric antigen receptor-expressing T (CAR-T) cells has attracted attention as an efficacious strategy for cancer treatment. To prove the efficacy and safety of CAR-T cell therapy, the elucidation of immunological mechanisms underlying it in mice is required. Although a retroviral vector (Rv) is mainly used for the introduction of CAR to murine T cells, gene transduction efficiency is generally less than 50%. The low transduction efficiency causes poor precision in the functional analysis of CAR-T cells. We attempted to improve the Rv gene transduction protocol to more efficiently generate functional CAR-T cells by optimizing the period of pre-cultivation and antibody stimulation. In the improved protocol, gene transduction efficiency to murine T cells was more than 90%. In addition, almost all of the prepared murine T cells expressed CAR after puromycin selection. These CAR-T cells had antigen-specific cytotoxic activity and secreted multiple cytokines by antigen stimulation. We believe that our optimized gene transduction protocol for murine T cells contributes to the advancement of T cell biology and development of immunotherapy using genetically engineered T cells. - Highlights: • We established highly efficient gene transduction protocols for murine T cells. • CD8"+ CAR-T cells had antigen-specific cytotoxic activity. • CD4"+ CAR-T cells secreted multiple cytokines by antigen stimulation. • This finding can contribute to the development of T-cell biology and immunotherapy.

Highly efficient gene transfer using a retroviral vector into murine T cells for preclinical chimeric antigen receptor-expressing T cell therapy

Energy Technology Data Exchange (ETDEWEB)

Kusabuka, Hotaka; Fujiwara, Kento; Tokunaga, Yusuke; Hirobe, Sachiko; Nakagawa, Shinsaku, E-mail: nakagawa@phs.osaka-u.ac.jp; Okada, Naoki, E-mail: okada@phs.osaka-u.ac.jp

2016-04-22

Adoptive immunotherapy using chimeric antigen receptor-expressing T (CAR-T) cells has attracted attention as an efficacious strategy for cancer treatment. To prove the efficacy and safety of CAR-T cell therapy, the elucidation of immunological mechanisms underlying it in mice is required. Although a retroviral vector (Rv) is mainly used for the introduction of CAR to murine T cells, gene transduction efficiency is generally less than 50%. The low transduction efficiency causes poor precision in the functional analysis of CAR-T cells. We attempted to improve the Rv gene transduction protocol to more efficiently generate functional CAR-T cells by optimizing the period of pre-cultivation and antibody stimulation. In the improved protocol, gene transduction efficiency to murine T cells was more than 90%. In addition, almost all of the prepared murine T cells expressed CAR after puromycin selection. These CAR-T cells had antigen-specific cytotoxic activity and secreted multiple cytokines by antigen stimulation. We believe that our optimized gene transduction protocol for murine T cells contributes to the advancement of T cell biology and development of immunotherapy using genetically engineered T cells. - Highlights: • We established highly efficient gene transduction protocols for murine T cells. • CD8{sup +} CAR-T cells had antigen-specific cytotoxic activity. • CD4{sup +} CAR-T cells secreted multiple cytokines by antigen stimulation. • This finding can contribute to the development of T-cell biology and immunotherapy.

Downregulation of miR-210 expression inhibits proliferation, induces apoptosis and enhances radiosensitivity in hypoxic human hepatoma cells in vitro

International Nuclear Information System (INIS)

Yang, Wei; Sun, Ting; Cao, Jianping; Liu, Fenju; Tian, Ye; Zhu, Wei

2012-01-01

Hypoxia is a common feature of solid tumors and an important contributor to tumor radioresistance. miR-210 is the most consistently and robustly induced microRNA under hypoxia in different types of tumor cells and normal cells. In the present study, to explore the feasibility of miR-210 as an effective therapeutic target, lentiviral-mediated anti-sense miR-210 gene transfer technique was employed to downregulate miR-210 expression in hypoxic human hepatoma SMMC-7721, HepG2 and HuH7 cells, and phenotypic changes of which were analyzed. Hypoxia led to an increased hypoxia inducible factor-1α (HIF-1α) and miR-210 expression and cell arrest in the G 0 /G 1 phase in all cell lines. miR-210 downregulation significantly suppressed cell viability, induced cell arrest in the G 0 /G 1 phase, increased apoptotic rate and enhanced radiosensitivity in hypoxic human hepatoma cells. Moreover, apoptosis-inducing factor, mitochondrion-associated, 3 (AIFM3) was identified as a direct target gene of miR-210. AIFM3 downregulation by siRNA attenuated radiation induced apoptosis in miR-210 downregulated hypoxic human hepatoma cells. Taken together, these data suggest that miR-210 might be a potential therapeutic target and specific inhibition of miR-210 expression in combination with radiotherapy might be expected to exert strong anti-tumor effect on hypoxic human hepatoma cells. -- Highlights: ► miR-210 downregulation radiosensitized hypoxic hepatoma. ► AIFM3 was identified as a direct target gene of miR-210. ► miR-210 might be a therapeutic target to hypoxic hepatoma.

Transgene IL-6 Enhances DC-Stimulated CTL Responses by Counteracting CD4+25+Foxp3+ Regulatory T Cell Suppression via IL-6-Induced Foxp3 Downregulation

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Kalpana Kalyanasundaram Bhanumathy

2014-03-01

Full Text Available Dendritic cells (DCs, the most potent antigen-presenting cells have been extensively applied in clinical trials for evaluation of antitumor immunity. However, the efficacy of DC-mediated cancer vaccines is still limited as they are unable to sufficiently break the immune tolerance. In this study, we constructed a recombinant adenoviral vector (AdVIL-6 expressing IL-6, and generated IL-6 transgene-engineered DC vaccine (DCOVA/IL-6 by transfection of murine bone marrow-derived ovalbumin (OVA-pulsed DCs (DCOVA with AdVIL-6. We then assessed DCOVA/IL-6-stimulated cytotoxic T-lymphocyte (CTL responses and antitumor immunity in OVA-specific animal tumor model. We demonstrate that DCOVA/IL-6 vaccine up-regulates expression of DC maturation markers, secretes transgene-encoded IL-6, and more efficiently stimulates OVA-specific CTL responses and therapeutic immunity against OVA-expressing B16 melanoma BL6-10OVA in vivo than the control DCOVA/Null vaccine. Moreover, DCOVA/IL-6-stimulated CTL responses were relatively maintained in mice with transfer of CD4+25+Foxp3+ Tr-cells, but significantly reduced when treated with anti-IL-6 antibody. In addition, we demonstrate that IL-6 down-regulates Foxp3-expression of CD4+25+Foxp3+ Tr-cells in vitro. Taken together, our results demonstrate that AdV-mediated IL-6 transgene-engineered DC vaccine stimulates potent CTL responses and antitumor immunity by counteracting CD4+25+ Tr immunosuppression via IL-6-induced Foxp3 down-regulation. Thus, IL-6 may be a good candidate for engineering DCs for cancer immunotherapy.

Proliferating Cell Nuclear Antigen (PCNA) Regulates Primordial Follicle Assembly by Promoting Apoptosis of Oocytes in Fetal and Neonatal Mouse Ovaries

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Zhang, Yuanwei; Jiang, Xiaohua; Zhang, Huan; Ma, Tieliang; Zheng, Wei; Sun, Rui; Shen, Wei; Sha, Jiahao; Cooke, Howard J.; Shi, Qinghua

2011-01-01

Primordial follicles, providing all the oocytes available to a female throughout her reproductive life, assemble in perinatal ovaries with individual oocytes surrounded by granulosa cells. In mammals including the mouse, most oocytes die by apoptosis during primordial follicle assembly, but factors that regulate oocyte death remain largely unknown. Proliferating cell nuclear antigen (PCNA), a key regulator in many essential cellular processes, was shown to be differentially expressed during these processes in mouse ovaries using 2D-PAGE and MALDI-TOF/TOF methodology. A V-shaped expression pattern of PCNA in both oocytes and somatic cells was observed during the development of fetal and neonatal mouse ovaries, decreasing from 13.5 to 18.5 dpc and increasing from 18.5 dpc to 5 dpp. This was closely correlated with the meiotic prophase I progression from pre-leptotene to pachytene and from pachytene to diplotene when primordial follicles started to assemble. Inhibition of the increase of PCNA expression by RNA interference in cultured 18.5 dpc mouse ovaries strikingly reduced the apoptosis of oocytes, accompanied by down-regulation of known pro-apoptotic genes, e.g. Bax, caspase-3, and TNFα and TNFR2, and up-regulation of Bcl-2, a known anti-apoptotic gene. Moreover, reduced expression of PCNA was observed to significantly increase primordial follicle assembly, but these primordial follicles contained fewer guanulosa cells. Similar results were obtained after down-regulation by RNA interference of Ing1b, a PCNA-binding protein in the UV-induced apoptosis regulation. Thus, our results demonstrate that PCNA regulates primordial follicle assembly by promoting apoptosis of oocytes in fetal and neonatal mouse ovaries. PMID:21253613

Proliferating cell nuclear antigen (PCNA regulates primordial follicle assembly by promoting apoptosis of oocytes in fetal and neonatal mouse ovaries.

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Bo Xu

Full Text Available Primordial follicles, providing all the oocytes available to a female throughout her reproductive life, assemble in perinatal ovaries with individual oocytes surrounded by granulosa cells. In mammals including the mouse, most oocytes die by apoptosis during primordial follicle assembly, but factors that regulate oocyte death remain largely unknown. Proliferating cell nuclear antigen (PCNA, a key regulator in many essential cellular processes, was shown to be differentially expressed during these processes in mouse ovaries using 2D-PAGE and MALDI-TOF/TOF methodology. A V-shaped expression pattern of PCNA in both oocytes and somatic cells was observed during the development of fetal and neonatal mouse ovaries, decreasing from 13.5 to 18.5 dpc and increasing from 18.5 dpc to 5 dpp. This was closely correlated with the meiotic prophase I progression from pre-leptotene to pachytene and from pachytene to diplotene when primordial follicles started to assemble. Inhibition of the increase of PCNA expression by RNA interference in cultured 18.5 dpc mouse ovaries strikingly reduced the apoptosis of oocytes, accompanied by down-regulation of known pro-apoptotic genes, e.g. Bax, caspase-3, and TNFα and TNFR2, and up-regulation of Bcl-2, a known anti-apoptotic gene. Moreover, reduced expression of PCNA was observed to significantly increase primordial follicle assembly, but these primordial follicles contained fewer granulosa cells. Similar results were obtained after down-regulation by RNA interference of Ing1b, a PCNA-binding protein in the UV-induced apoptosis regulation. Thus, our results demonstrate that PCNA regulates primordial follicle assembly by promoting apoptosis of oocytes in fetal and neonatal mouse ovaries.

Modulation of antigen presenting cell functions during chronic HPV infection

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Abate Assefa Bashaw

2017-12-01

Full Text Available High-risk human papillomaviruses (HR-HPV infect basal keratinocytes, where in some individuals they evade host immune responses and persist. Persistent HR-HPV infection of the cervix causes precancerous neoplasia that can eventuate in cervical cancer. Dendritic cells (DCs are efficient in priming/cross-priming antigen-specific T cells and generating antiviral and antitumor cytotoxic CD8+ T cells. However, HR-HPV have adopted various immunosuppressive strategies, with modulation of DC function crucial to escape from the host adaptive immune response. HPV E6 and E7 oncoproteins alter recruitment and localization of epidermal DCs, while soluble regulatory factors derived from HPV-induced hyperplastic epithelium change DC development and influence initiation of specific cellular immune responses. This review focuses on current evidence for HR-HPV manipulation of antigen presentation in dendritic cells and escape from host immunity.

77 FR 3482 - Prospective Grant of Exclusive License: Development of T Cell Receptors and Chimeric Antigen...

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2012-01-24

... Exclusive License: Development of T Cell Receptors and Chimeric Antigen Receptors Into Therapeutics for.... 61/473,409 entitled ``Anti-epidermal growth factor receptor variant III chimeric antigen receptors... EGFRvIII chimeric antigen (CARs) and methods of using these engineered T cells to treat and/or prevent...

Antigen-specific T8+ human clone of cells with a nonspecific augmenting function on the T4 cell-B cell helper interaction

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Brines, R.D.; Sia, D.Y.; Lehner, T.

1987-01-01

The authors isolated a T8 + T3 + Ia + clone of cells from the peripheral blood mononuclear cells of a healthy subject. The clone was expanded and maintained with autologous feed cells, interleukin 2, and a streptococcal antigen. The T8 + clone of cells responded specifically to the streptococcal antigen, in the absence of accessory cells,and released a soluble factor. Both the cloned cells and the corresponding soluble factor expressed augmenting helper but not suppressor activity. The augmenting helper activity for B cell antibody synthesis was demonstrable only in the presence of autologous T 4 cells. Radioimmunoassay was used to measure antibodies. Although stimulation of the T8 + cloned cells was antigen-specific, the resulting soluble factor elicited nonspecific antibody synthesis in the presence of T4 and B cells. The T8 + cloned cell-derived factor was adsorbed by B cells but not by T4 cells. Preliminary studies suggest that the factor has the properties of a B cell growth factor. They suggest that the T8 + population consists of functionally heterogeneous cell subsets, some that have suppressor function and others that augment the T4 + helper-inducer activity in B cell antibody synthesis

Prolonged antigen presentation is required for optimal CD8+ T cell responses against malaria liver stage parasites.

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Ian A Cockburn

2010-05-01

Full Text Available Immunization with irradiated sporozoites is currently the most effective vaccination strategy against liver stages of malaria parasites, yet the mechanisms underpinning the success of this approach are unknown. Here we show that the complete development of protective CD8+ T cell responses requires prolonged antigen presentation. Using TCR transgenic cells specific for the malaria circumsporozoite protein, a leading vaccine candidate, we found that sporozoite antigen persists for over 8 weeks after immunization--a remarkable finding since irradiated sporozoites are incapable of replication and do not differentiate beyond early liver stages. Persisting antigen was detected in lymphoid organs and depends on the presence of CD11c+ cells. Prolonged antigen presentation enhanced the magnitude of the CD8+ T cell response in a number of ways. Firstly, reducing the time primed CD8+ T cells were exposed to antigen in vivo severely reduced the final size of the developing memory population. Secondly, fully developed memory cells expanded in previously immunized mice but not when transferred to naïve animals. Finally, persisting antigen was able to prime naïve cells, including recent thymic emigrants, to become functional effector cells capable of eliminating parasites in the liver. Together these data show that the optimal development of protective CD8+ T cell immunity against malaria liver stages is dependent upon the prolonged presentation of sporozoite-derived antigen.

Semi-allogeneic dendritic cells can induce antigen-specific T-cell activation, which is not enhanced by concurrent alloreactivity.

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Wells, James W; Cowled, Chris J; Darling, David; Guinn, Barbara-Ann; Farzaneh, Farzin; Noble, Alistair; Galea-Lauri, Joanna

2007-12-01

Alloreactive T-cell responses are known to result in the production of large amounts of proinflammatory cytokines capable of activating and maturing dendritic cells (DC). However, it is unclear whether these allogeneic responses could also act as an adjuvant for concurrent antigen-specific responses. To examine effects of simultaneous alloreactive and antigen-specific T-cell responses induced by semi-allogeneic DC. Semi-allogeneic DC were generated from the F(1) progeny of inbred strains of mice (C57BL/6 and C3H, or C57BL/6 and DBA). We directly primed antigen-specific CD8(+) and CD4(+) T-cells from OT-I and OT-II mice, respectively, in the absence of allogeneic responses, in vitro, and in the presence or absence of alloreactivity in vivo. In vitro, semi-allogeneic DC cross-presented ovalbumin (OVA) to naïve CD8(+) OT-I transgenic T-cells, primed naïve CD4(+) OT-II transgenic T-cells and could stimulate strong alloreactive T-cell proliferation in a primary mixed lymphocyte reaction (MLR). In vivo, semi-allogeneic DC migrated efficiently to regional lymph nodes but did not survive there as long as autologous DC. In addition, they were not able to induce cytotoxic T-lymphocyte (CTL) activity to a target peptide, and only weakly stimulated adoptively transferred OT-II cells. The CD4(+) response was unchanged in allo-tolerized mice, indicating that alloreactive T-cell responses could not provide help for concurrently activated antigen-specific responses. In an EL4 tumour-treatment model, vaccination with semi-allogeneic DC/EL4 fusion hybrids, but not allogeneic DC/EL4 hybrids, significantly increased mouse survival. Expression of self-Major histocompatibility complex (MHC) by semi-allogeneic DC can cause the induction of antigen-specific immunity, however, concurrently activated allogeneic bystander responses do not provide helper or adjuvant effects.

Three-day dendritic cells for vaccine development: Antigen uptake, processing and presentation

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Schendel Dolores J

2010-09-01

Full Text Available Abstract Background Antigen-loaded dendritic cells (DC are capable of priming naïve T cells and therefore represent an attractive adjuvant for vaccine development in anti-tumor immunotherapy. Numerous protocols have been described to date using different maturation cocktails and time periods for the induction of mature DC (mDC in vitro. For clinical application, the use of mDC that can be generated in only three days saves on the costs of cytokines needed for large scale vaccine cell production and provides a method to produce cells within a standard work-week schedule in a GMP facility. Methods In this study, we addressed the properties of antigen uptake, processing and presentation by monocyte-derived DC prepared in three days (3d mDC compared with conventional DC prepared in seven days (7d mDC, which represent the most common form of DC used for vaccines to date. Results Although they showed a reduced capacity for spontaneous antigen uptake, 3d mDC displayed higher capacity for stimulation of T cells after loading with an extended synthetic peptide that requires processing for MHC binding, indicating they were more efficient at antigen processing than 7d DC. We found, however, that 3d DC were less efficient at expressing protein after introduction of in vitro transcribed (ivtRNA by electroporation, based on published procedures. This deficit was overcome by altering electroporation parameters, which led to improved protein expression and capacity for T cell stimulation using low amounts of ivtRNA. Conclusions This new procedure allows 3d mDC to replace 7d mDC for use in DC-based vaccines that utilize long peptides, proteins or ivtRNA as sources of specific antigen.

The human E48 antigen, highly homologous to the murine Ly-6 antigen ThB, is a GPI-anchored molecule apparently involved in keratinocyte cell-cell adhesion

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Brakenhoff, R H; Gerretsen, M; Knippels, E M; van Dijk, M.; van Essen, H; Weghuis, D O; Sinke, R J; Snow, G B; van Dongen, G A

The E48 antigen, a putative human homologue of the 20-kD protein present in desmosomal preparations of bovine muzzle, and formerly called desmoglein III (dg4), is a promising target antigen for antibody-based therapy of squamous cell carcinoma in man. To anticipate the effect of high antibody dose

Regional Delivery of Chimeric Antigen Receptor (CAR) T-Cells for Cancer Therapy.

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Sridhar, Praveen; Petrocca, Fabio

2017-07-18

Chimeric Antigen Receptor (CAR) T-cells are T-cells with recombinant receptors targeted to tumor antigens. CAR-T cell therapy has emerged as a mode of immunotherapy and is now being extensively explored in hematologic cancer. In contrast, CAR-T cell use in solid tumors has been hampered by multiple obstacles. Several approaches have been taken to circumvent these obstacles, including the regional delivery of CAR-T cells. Regional CAR-T cell delivery can theoretically compensate for poor T-cell trafficking and tumor antigen specificity while avoiding systemic toxicity associated with intravenous delivery. We reviewed completed clinical trials for the treatment of glioblastoma and metastatic colorectal cancer and examined the data in these studies for safety, efficacy, and potential advantages that regional delivery may confer over systemic delivery. Our appraisal of the available literature revealed that regional delivery of CAR-T cells in both glioblastoma and hepatic colorectal metastases was generally well tolerated and efficacious in select instances. We propose that the regional delivery of CAR-T cells is an area of potential growth in the solid tumor immunotherapy, and look towards future clinical trials in head and neck cancer, mesothelioma, and peritoneal carcinomatosis as the use of this technique expands.

Regional Delivery of Chimeric Antigen Receptor (CAR T-Cells for Cancer Therapy

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Praveen Sridhar

2017-07-01

Full Text Available Chimeric Antigen Receptor (CAR T-cells are T-cells with recombinant receptors targeted to tumor antigens. CAR-T cell therapy has emerged as a mode of immunotherapy and is now being extensively explored in hematologic cancer. In contrast, CAR-T cell use in solid tumors has been hampered by multiple obstacles. Several approaches have been taken to circumvent these obstacles, including the regional delivery of CAR-T cells. Regional CAR-T cell delivery can theoretically compensate for poor T-cell trafficking and tumor antigen specificity while avoiding systemic toxicity associated with intravenous delivery. We reviewed completed clinical trials for the treatment of glioblastoma and metastatic colorectal cancer and examined the data in these studies for safety, efficacy, and potential advantages that regional delivery may confer over systemic delivery. Our appraisal of the available literature revealed that regional delivery of CAR-T cells in both glioblastoma and hepatic colorectal metastases was generally well tolerated and efficacious in select instances. We propose that the regional delivery of CAR-T cells is an area of potential growth in the solid tumor immunotherapy, and look towards future clinical trials in head and neck cancer, mesothelioma, and peritoneal carcinomatosis as the use of this technique expands.

Antigen presentation and MHC class II expression by human esophageal epithelial cells: role in eosinophilic esophagitis.

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Mulder, Daniel J; Pooni, Aman; Mak, Nanette; Hurlbut, David J; Basta, Sameh; Justinich, Christopher J

2011-02-01

Professional antigen-presenting cells (APCs) play a crucial role in initiating immune responses. Under pathological conditions, epithelial cells at mucosal surfaces act as nonprofessional APCs, thereby regulating immune responses at the site of exposure. Epithelial cells in the esophagus may contribute to the pathogenesis of eosinophilic esophagitis (EoE) by presenting antigens on the major histocompatibility complex (MHC) class II. Our goal was to demonstrate the ability of esophageal epithelial cells to process and present antigens on the MHC class II system and to investigate the contribution of epithelial cell antigen presentation to EoE. Immunohistochemistry detected HLA-DR, CD80, and CD86 expression and enzyme-linked immunosorbent assay detected interferon-γ (IFNγ) in esophageal biopsies. Antigen presentation was studied using the human esophageal epithelial cell line HET-1A by reverse transcriptase-PCR, flow cytometry, and confocal microscopy. T helper cell lymphocyte proliferation was assessed by flow cytometry and IL-2 secretion. IFNγ and MHC class II were increased in mucosa of patients with EoE. IFNγ increased mRNA of HLA-DP, HLA-DQ, HLA-DR, and CIITA in HET-1A cells. HET-1A engulfed cell debris and processed ovalbumin. HET-1A cells expressed HLA-DR after IFNγ treatment. HET-1A stimulated T helper cell activation. In this study, we demonstrated the ability of esophageal epithelial cells to act as nonprofessional APCs in the presence of IFNγ. Esophageal epithelial cell antigen presentation may contribute to the pathophysiology of eosinophilic esophagitis. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Oral dendritic cells mediate antigen-specific tolerance by stimulating TH1 and regulatory CD4+ T cells.

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Mascarell, Laurent; Lombardi, Vincent; Louise, Anne; Saint-Lu, Nathalie; Chabre, Henri; Moussu, Hélène; Betbeder, Didier; Balazuc, Anne-Marie; Van Overtvelt, Laurence; Moingeon, Philippe

2008-09-01

A detailed characterization of oral antigen-presenting cells is critical to improve second-generation sublingual allergy vaccines. To characterize oral dendritic cells (DCs) within lingual and buccal tissues from BALB/c mice with respect to their surface phenotype, distribution, and capacity to polarize CD4(+) T-cell responses. In situ analysis of oral DCs was performed by immunohistology. Purified DCs were tested in vitro for their capacity to capture, process, and present the ovalbumin antigen to naive CD4(+) T cells. In vivo priming of ovalbumin-specific T cells adoptively transferred to BALB/c mice was analyzed by cytofluorometry in cervical lymph nodes after sublingual administration of mucoadhesive ovalbumin. Three subsets of oral DCs with a distinct tissue distribution were identified: (1) a minor subset of CD207(+) Langerhans cells located in the mucosa itself, (2) a major subpopulation of CD11b(+)CD11c(-) and CD11b(+)CD11c(+) myeloid DCs at the mucosal/submucosal interface, and (3) B220(+)120G8(+) plasmacytoid DCs found in submucosal tissues. Purified myeloid and plasmacytoid oral DCs capture and process the antigen efficiently and are programmed to elicit IFN-gamma and/or IL-10 production together with a suppressive function in naive CD4(+) T cells. Targeting the ovalbumin antigen to oral DCs in vivo by using mucoadhesive particles establishes tolerance in the absence of cell depletion through the stimulation of IFN-gamma and IL-10-producing CD4(+) regulatory T cells in cervical lymph nodes. The oral immune system is composed of various subsets of tolerogenic DCs organized in a compartmentalized manner and programmed to induce T(H)1/regulatory T-cell responses.

Shedding of CD9 antigen into cerebrospinal fluid by acute lymphoblastic leukemia cells.

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Komada, Y; Ochiai, H; Shimizu, K; Azuma, E; Kamiya, H; Sakurai, M

1990-07-01

The accurate identification of small numbers of leukemic cells in the cerebrospinal fluid (CSF) presents a diagnostic problem in the treatment of acute lymphoblastic leukemia (ALL). We demonstrated that soluble CD9 antigen was shed into CSF obtained from children with ALL, using enzyme-linked immunosorbent assay (ELISA), which used the activity of CD9 antigen to bind the Ricinus communis agglutinin (RCA1) and a monoclonal antibody, SJ-9A4, simultaneously. Using RCA1/SJ-9A4 ELISA, CD9 antigen was detectable in CSF but not in plasma from 12 cases of CD9+ ALL in central nervous system (CNS) relapse. However, CD9 antigen was not released into CSF from 11 cases of CD9- ALL with CNS involvement, 136 cases of CD9+ ALL in complete remission (CR), 29 cases of CD9- ALL in CR, or 21 cases of aseptic meningitis. Interestingly, the levels of CD9 antigen were elevated in CSF from 7 of 10 CD9+ ALL patients without cytologically proven CNS involvement at diagnosis, with subsequent return to undetectable levels after initial induction chemotherapy was begun. In addition, sequential analysis of CSF from a 5-year-old boy with CD9+ ALL in CNS relapse showed that levels of CD9 antigen correlated well with the number of leukemic cells in CSF. Serial quantitative analysis of CD9 antigen in CSF could be useful to detect the proliferation of residual leukemic cells before the clinical manifestation.

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

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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.

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

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Ewoud Bernardus Compeer

2012-03-01

Full Text Available The cross-presentation of endocytosed antigen as peptide/class I MHC 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 (APC capable of antigen cross-presentation, description 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 highlight DC-intrinsic mechanisms that facilitate the cross-presentation of endocytosed antigen, including receptor-mediated uptake, recycling and maturation including the sorting of membrane proteins, dynamic remodeling of endosomal structures and cell-surface directed endosomal trafficking. We will conclude with description of pathogen-induced deviation of endosomal processing, and discuss how immune evasion strategies pertaining endosomal trafficking may preclude antigen cross-presentation.

Down-regulation of Transducin-Like Enhancer of Split protein 4 in hepatocellular carcinoma promotes cell proliferation and epithelial-Mesenchymal-Transition

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Wu, Xiao-cai; Xiao, Cui-cui; Li, Hua [Department of Hepatic Surgery, 3rd Affiliated Hospital of Sun Yat-sen University, Guangzhou (China); Guangdong Provincial Key Laboratory of Liver Disease Research, Guangzhou (China); Tai, Yan; Zhang, Qi [Guangdong Provincial Key Laboratory of Liver Disease Research, Guangzhou (China); Yang, Yang, E-mail: yysysu2@163.com [Department of Hepatic Surgery, 3rd Affiliated Hospital of Sun Yat-sen University, Guangzhou (China)

2016-08-19

Background: Transducin-Like Enhancer of Split protein 4 (TLE4) has been reported to be involved in some subsets of acute myeloid leukemia and colorectal cancer. In the present study, we aimed to explore the role of TLE4 in tumorigenesis and cancer progression in hepatocellular carcinoma (HCC). Methods: The expression pattern of TLE4 in HCC was determined by Western-blot and qRT-PCR, gain-of-function and loss-of-function was used to explore the biological role of TLE4 in HCC cells. A xenograft model was established to confirm its effects on proliferation. Results: The protein expression levels of TLE4 were significantly down-regulated in HCC tissues compared to matched adjacent normal liver tissues. In vitro, down-regulation of TLE4 in Huh7 or SMMC-7721 promoted cell proliferation and ectopical expression of TLE4 in Hep3B or Bel-7404 suppressed cell proliferation. In addition, the cell colony formation ability was enhanced after down-regulation of TLE4 expression in Huh-7 but suppressed after over-expression in Hep3B. Furthermore, down-regulation of TLE4 increased the cell invasion ability, as well as increased the expression level of Vimentin and decreased that of E-cadherin, indicating a phenotype of epithelial-mesenchymal transition (EMT) in HCC cells. On the contrary, ectopical expression of TLE4 in HCC cells decreased the cell invasion ability and inhibited EMT. In vivo, compared to control group, xenograft tumor volumes were significantly decreased in TLE4 overexpression group. Conclusions: These results demonstrated that TLE4 might play important regulatory roles in cellular proliferation and EMT process in HCC. - Highlights: • TLE4 is significantly down-regulated in HCC samples. • Down regulated of TLE4 in HCC cells promotes cell proliferation. • Down regulated of TLE4 in HCC cells promotes epithelial-to-mesenchymal transition.

Protein antigenic structures recognized by T cells: potential applications to vaccine design.

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Berzofsky, J A; Cease, K B; Cornette, J L; Spouge, J L; Margalit, H; Berkower, I J; Good, M F; Miller, L H; DeLisi, C

1987-08-01

In summary, our results using the model protein antigen myoglobin indicated, in concordance with others, that helper T lymphocytes recognize a limited number of immunodominant antigenic sites of any given protein. Such immunodominant sites are the focus of a polyclonal response of a number of different T cells specific for distinct but overlapping epitopes. Therefore, the immunodominance does not depend on the fine specificity of any given clone of T cells, but rather on other factors, either intrinsic or extrinsic to the structure of the antigen. A major extrinsic factor is the MHC of the responding individual, probably due to a requirement for the immunodominant peptides to bind to the MHC of presenting cells in that individual. In looking for intrinsic factors, we noted that both immunodominant sites of myoglobin were amphipathic helices, i.e., helices having hydrophilic and hydrophobic residues on opposite sides. Studies with synthetic peptides indicated that residues on the hydrophilic side were necessary for T-cell recognition. However, unfolding of the native protein was shown to be the apparent goal of processing of antigen, presumably to expose something not already exposed on the native molecule, such as the hydrophobic sides of these helices. We propose that such exposure is necessary to interact with something on the presenting cell, such as MHC or membrane, where we have demonstrated the presence of antigenic peptides by blocking of presentation of biotinylated peptide with avidin. The membrane may serve as a short-term memory of peptides from antigens encountered by the presenting cell, for dynamic sampling by MHC molecules to be available for presentation to T cells. These ideas, together with the knowledge that T-cell recognition required only short peptides and therefore had to be based only on primary or secondary structure, not tertiary folding of the native protein, led us to propose that T-cell immunodominant epitopes may tend to be amphipathic

3-Bromopyruvate induces apoptosis in breast cancer cells by downregulating Mcl-1 through the PI3K/Akt signaling pathway.

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Liu, Zhe; Zhang, Yuan-Yuan; Zhang, Qian-Wen; Zhao, Su-Rong; Wu, Cheng-Zhu; Cheng, Xiu; Jiang, Chen-Chen; Jiang, Zhi-Wen; Liu, Hao

2014-04-01

The hexokinase inhibitor 3-bromopyruvate (3-BrPA) can inhibit glycolysis in tumor cells to reduce ATP production, resulting in apoptosis. However, as 3-BrPA is an alkylating agent, its cytotoxic action may be induced by other molecular mechanisms. The results presented here reveal that 3-BrPA-induced apoptosis is caspase independent. Further, 3-BrPA induces the generation of reactive oxygen species in MDA-MB-231 cells, leading to mitochondria-mediated apoptosis. These results suggest that caspase-independent apoptosis may be induced by the generation of reactive oxygen species. In this study, we also demonstrated that 3-BrPA induces apoptosis through the downregulation of myeloid cell leukemia-1 (Mcl-1) in MDA-MB-231 breast cancer cells. The results of Mcl-1 knockdown indicate that Mcl-1 plays an important role in 3-BrPA-induced apoptosis. Further, the upregulation of Mcl-1 expression in 3-BrPA-treated MDA-MB-231 cells significantly increases cell viability. In addition, 3-BrPA treatment resulted in the downregulation of p-Akt, suggesting that 3-BrPA may downregulate Mcl-1 through the phosphoinositide-3-kinase/Akt pathway. These findings indicate that 3-BrPA induces apoptosis in breast cancer cells by downregulating Mcl-1 through the phosphoinositide-3-kinase/Akt signaling pathway.

Effects of radiation on the expression of antigens on the membranes of human adenocarcinoma cells

International Nuclear Information System (INIS)

Hareyama, Masato; Imai, Kozo; Oouchi, Atsushi; Shidou, Mitsuo; Takahashi, Hiroki; Koshiba, Hirohumi; Yachi, Akira; Morita, Kazuo

1992-01-01

We have investigated the effects of irradiation on the membranes of tumor cells. X-ray irradiation caused remarkable increases in the expression of tumor-associated antigens (YH206, CEA) and c-erbB-2 protein by flow cytometry, whereas IFN had no obvious effect on the expression of tumor-associated antigens and c-erbB-2 protein. On the other hand, the expression of MHC Class I and ICAM-1 antigen on the membrane by flow cytometry was enhanced by both irradiation and IFN. In addition, the irradiated cells, when analyzed using a CEA specific probe, showed remarkable increases in the CEA mRNA compared to IFN-treated cells. It is possible that enhancement of the expression of tumor-associated antigens and c-erbB-2 protein, together with the enhancement of that of MHC-Class I and ICAM-1, would help cytotoxic killer cells recognize the tumor cells. (author)

Cisplatin and ultra-violet-C synergistically down-regulate receptor tyrosine kinases in human colorectal cancer cells

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Kawaguchi Junji

2012-07-01

Full Text Available Abstract Background Platinum-containing anti-cancer drugs such as cisplatin are widely used for patients with various types of cancers, however, resistance to cisplatin is observed in some cases. Whereas we have recently reported that high dose UV-C (200 J/m² induces colorectal cancer cell proliferation by desensitization of EGFR, which leads oncogenic signaling in these cells, in this study we investigated the combination effect of low dose cisplatin (10 μM and low dose UV-C (10 J/m² on cell growth and apoptosis in several human colorectal cancer cells, SW480, DLD-1, HT29 and HCT116. Results The combination inhibited cell cycle and colony formation, while either cisplatin or UV-C alone had little effect. The combination also induced apoptosis in these cells. In addition, the combination caused the downregulation of EGFR and HER2. Moreover, UV-C alone caused the transient internalization of the EGFR, but with time EGFR recycled back to the cell surface, while cisplatin did not affect its localization. Surprisingly, the combination caused persistent internalization of the EGFR, which results in the lasting downregulation of the EGFR. Conclusions The combination of low dose cisplatin and low dose UV-C synergistically exerted anti-cancer effect by down-regulating RTK, such as EGFR and HER2. These findings may provide a novel strategy for the treatment of patients with colorectal cancer.

Healthy human T-Cell Responses to Aspergillus fumigatus antigens.

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Neelkamal Chaudhary

2010-02-01

Full Text Available Aspergillus fumigatus is associated with both invasive and allergic pulmonary diseases, in different hosts. The organism is inhaled as a spore, which, if not cleared from the airway, germinates into hyphal morphotypes that are responsible for tissue invasion and resultant inflammation. Hyphae secrete multiple products that function as antigens, evoking both a protective (T(H1-T(H17 and destructive allergic (T(H2 immunity. How Aspergillus allergens (Asp f proteins participate in the development of allergic sensitization is unknown.To determine whether Asp f proteins are strictly associated with T(H2 responses, or represent soluble hyphal products recognized by healthy hosts, human T cell responses to crude and recombinant products were characterized by ELISPOT. While responses (number of spots producing IFN-gamma, IL-4 or IL-17 to crude hyphal antigen preparations were weak, responses to recombinant Asp f proteins were higher. Recombinant allergens stimulated cells to produce IFN-gamma more so than IL-4 or IL-17. Volunteers exhibited a diverse CD4+ and CD8+ T cell antigen recognition profile, with prominent CD4 T(H1-responses to Asp f3 (a putative peroxismal membrane protein, Asp f9/16 (cell wall glucanase, Asp f11 (cyclophilin type peptidyl-prolyl isomerase and Asp f22 (enolase. Strong IFN-gamma responses were reproduced in most subjects tested over 6 month intervals.Products secreted after conidial germination into hyphae are differentially recognized by protective T cells in healthy, non-atopic individuals. Defining the specificity of the human T cell repertoire, and identifying factors that govern early responses may allow for development of novel diagnostics and therapeutics for both invasive and allergic Aspergillus diseases.

Lignans isolated from Campylotropis hirtella (Franch.) Schindl. decreased prostate specific antigen and androgen receptor expression in LNCaP cells.

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Han, Hui-Ying; Wang, Xiang-Hong; Wang, Nai-Li; Ling, Ming-Tat; Wong, Yong-Chuan; Yao, Xin-Sheng

2008-08-27

Accumulating epidemiological data suggest that Asian men have lower incidences of prostate cancer and benign prostate hyperplasia (BPH) compared with American and European populations and may have benefited from their higher intake of phytoestrogens in their diet. However, how these phytochemicals affect prostatic diseases is still unclear. In this study, we isolated six lignans from a plant, Campylotropis hirtella (Franch.) Schindl., which has been used as a folk medicine for treatment of BPH in China, through bioassay guided fractionation. They were dehydrodiconiferyl alcohol (C1), 4-[(-6-hydroxy-2,3-dihydro-1-benzofuran-3-yl)methyl]-5-methoxybenzene-1,3-diol (C2), erythro-guaiacylglycerol-beta-O-4'-coniferyl ether (C3), threo-guaiacylglycerol-beta-O-4'-coniferyl ether (C4), secoisolariciresinol (C5), and prupaside (C6), where C2 was identified as a new lignan analog. Their IC50 values for inhibition of prostate specific antigen (PSA) secretion were 19, 45, 110, 128, 137, and 186 microM, respectively, from C1 to C6 in LNCaP cells. Further study showed that C1-5 down-regulated cellular PSA expression and C1-4 also decreased androgen receptor (AR) expression in LNCaP cells. Furthermore, we investigated the proapoptotic effect of C1 on LNCaP cells. The active forms of caspase 3 associated with the specific proteolysis of poly (ADP-ribose) polymerase (PARP) were detected, and the antiapoptotic protein Bcl-2 was down-regulated after the treatment with C1. These results collectively indicated that these lignans may have chemopreventive or therapeutic actions for prostate cancer through suppressing AR signaling pathway and inducing apoptosis.

Dendritic cells take up and present antigens from viable and apoptotic polymorphonuclear leukocytes.

Directory of Open Access Journals (Sweden)

Carlos Alfaro

Full Text Available 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-2(d 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-2(d PMNs. If such PMNs, that cannot present antigens to OT-1 T cells, are immunomagnetically re-isolated and phagocytosed by H-2(b 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-2(d are coinjected in the footpad of mice with autologous DC (H-2(b. In summary, our results indicate that antigens phagocytosed by short-lived PMNs can be in turn internalized and productively cross-presented by DC.

Downregulation of miR-210 expression inhibits proliferation, induces apoptosis and enhances radiosensitivity in hypoxic human hepatoma cells in vitro

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Yang, Wei, E-mail: detachedy@yahoo.com.cn [Department of Radiobiology, School of Radiological Medicine and Protection, Soochow University, Suzhou (China); Sun, Ting [Brain and Nerve Research Laboratory, The First Affiliated Hospital, Soochow University, Suzhou (China); Cao, Jianping; Liu, Fenju [Department of Radiobiology, School of Radiological Medicine and Protection, Soochow University, Suzhou (China); Tian, Ye [Department of Radiotherapy and Oncology, The Second Affiliated Hospital, Soochow University, Suzhou (China); Zhu, Wei [Department of Radiobiology, School of Radiological Medicine and Protection, Soochow University, Suzhou (China)

2012-05-01

Hypoxia is a common feature of solid tumors and an important contributor to tumor radioresistance. miR-210 is the most consistently and robustly induced microRNA under hypoxia in different types of tumor cells and normal cells. In the present study, to explore the feasibility of miR-210 as an effective therapeutic target, lentiviral-mediated anti-sense miR-210 gene transfer technique was employed to downregulate miR-210 expression in hypoxic human hepatoma SMMC-7721, HepG2 and HuH7 cells, and phenotypic changes of which were analyzed. Hypoxia led to an increased hypoxia inducible factor-1{alpha} (HIF-1{alpha}) and miR-210 expression and cell arrest in the G{sub 0}/G{sub 1} phase in all cell lines. miR-210 downregulation significantly suppressed cell viability, induced cell arrest in the G{sub 0}/G{sub 1} phase, increased apoptotic rate and enhanced radiosensitivity in hypoxic human hepatoma cells. Moreover, apoptosis-inducing factor, mitochondrion-associated, 3 (AIFM3) was identified as a direct target gene of miR-210. AIFM3 downregulation by siRNA attenuated radiation induced apoptosis in miR-210 downregulated hypoxic human hepatoma cells. Taken together, these data suggest that miR-210 might be a potential therapeutic target and specific inhibition of miR-210 expression in combination with radiotherapy might be expected to exert strong anti-tumor effect on hypoxic human hepatoma cells. -- Highlights: Black-Right-Pointing-Pointer miR-210 downregulation radiosensitized hypoxic hepatoma. Black-Right-Pointing-Pointer AIFM3 was identified as a direct target gene of miR-210. Black-Right-Pointing-Pointer miR-210 might be a therapeutic target to hypoxic hepatoma.

Epigenetic down-regulated DDX10 promotes cell proliferation through Akt/NF-κB pathway in ovarian cancer

International Nuclear Information System (INIS)

Gai, Muhuizi; Bo, Qifang; Qi, Lixia

2016-01-01

Ovarian cancer contributes to the majority of ovarian cancer, while the molecular mechanisms remain elusive. Recently, some DEAD box protein 1 has been reported play a tumor suppressor role in ovarian cancer progression. However, the functions of DEAD box protein (DDX) members in ovarian cancer development remain largely unknown. In current study, we retrieved GEO databases and surprisingly found that DDX10 is significantly down-regulated in ovarian cancer tissues compared with normal ovary. These findings suggest that DDX10 might also play a suppressive role in ovarian cancer. We then validated the down-regulated expression pattern of DDX10 in fresh ovarian cancer tissues. Furthermore, both loss- and gain-functions assays reveal that the down-regulated DDX10 could promote ovarian cancer proliferation in vitro and the xenograft subcutaneous tumor formation assays confirmed these findings in vivo. In addition, we found that DDX10 is epigenetic silenced by miR-155-5p in ovarian cancer. Moreover, we further preliminary illustrated that down-regulated DDX10 promotes ovarian cancer cell proliferation through Akt/NF-κB pathway. Taken together, in current study, we found a novel tumor suppressor, DDX10, is epigenetic silenced by miR-155-5p in ovarian cancer, and the down-regulated expression pattern of DDX10 promotes ovarian cancer proliferation through Akt/NF-κB pathway. Our findings shed the light that DDX families might be a novel for ovarian cancer treatment. - Highlights: • A novel DEAD box protein, DDX10 is significantly down-regulated in ovarian cancer tissues. • Down-regulated DDX10 promotes ovarian cancer cell proliferation and growth both in vitro and in vivo. • miR-155-5p is highly expressed in ovarian cancer tissues and epigenetically targets DDX10. • DDX10 and miR-155-5p regulates Akt/p65 axis in ovarian cancer cells.

Epigenetic down-regulated DDX10 promotes cell proliferation through Akt/NF-κB pathway in ovarian cancer

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Gai, Muhuizi; Bo, Qifang; Qi, Lixia, E-mail: lixiaqi_dph@sina.com

2016-01-22

Ovarian cancer contributes to the majority of ovarian cancer, while the molecular mechanisms remain elusive. Recently, some DEAD box protein 1 has been reported play a tumor suppressor role in ovarian cancer progression. However, the functions of DEAD box protein (DDX) members in ovarian cancer development remain largely unknown. In current study, we retrieved GEO databases and surprisingly found that DDX10 is significantly down-regulated in ovarian cancer tissues compared with normal ovary. These findings suggest that DDX10 might also play a suppressive role in ovarian cancer. We then validated the down-regulated expression pattern of DDX10 in fresh ovarian cancer tissues. Furthermore, both loss- and gain-functions assays reveal that the down-regulated DDX10 could promote ovarian cancer proliferation in vitro and the xenograft subcutaneous tumor formation assays confirmed these findings in vivo. In addition, we found that DDX10 is epigenetic silenced by miR-155-5p in ovarian cancer. Moreover, we further preliminary illustrated that down-regulated DDX10 promotes ovarian cancer cell proliferation through Akt/NF-κB pathway. Taken together, in current study, we found a novel tumor suppressor, DDX10, is epigenetic silenced by miR-155-5p in ovarian cancer, and the down-regulated expression pattern of DDX10 promotes ovarian cancer proliferation through Akt/NF-κB pathway. Our findings shed the light that DDX families might be a novel for ovarian cancer treatment. - Highlights: • A novel DEAD box protein, DDX10 is significantly down-regulated in ovarian cancer tissues. • Down-regulated DDX10 promotes ovarian cancer cell proliferation and growth both in vitro and in vivo. • miR-155-5p is highly expressed in ovarian cancer tissues and epigenetically targets DDX10. • DDX10 and miR-155-5p regulates Akt/p65 axis in ovarian cancer cells.

Granulocytes: New Members of the Antigen-Presenting Cell Family

Directory of Open Access Journals (Sweden)

Ang Lin

2017-12-01

Full Text Available Granulocytes, the most abundant types of leukocytes, are the first line of defense against pathogen invasion. However, the plasticity and diversity of granulocytes have been increasingly revealed, especially with regard to their versatile functions in orchestrating adaptive immune responses. A substantial body of recent evidence demonstrates that granulocytes can acquire the function as antigen-presenting cells under pathological or inflammatory conditions. In addition, they can acquire surface expression of MHC class II and costimulatory molecules as well as T cell stimulatory behavior when cultured with selected cytokines. The classic view of granulocytes as terminally differentiated, short-lived phagocytes is therefore changing to phenotypically and functionally heterogeneous cells that are engaged in cross-talk with other leukocyte populations and provide an additional link between innate and adaptive immunity. In this brief review, we summarize the current knowledge on the antigen-presenting capacity of granulocyte subsets (neutrophils, eosinophils, and basophils. Underlying mechanisms, relevant physiological significance and potential controversies are also discussed.

Elutriated lymphocytes for manufacturing chimeric antigen receptor T cells

OpenAIRE

Stroncek, David F.; Lee, Daniel W.; Ren, Jiaqiang; Sabatino, Marianna; Highfill, Steven; Khuu, Hanh; Shah, Nirali N.; Kaplan, Rosandra N.; Fry, Terry J.; Mackall, Crystal L.

2017-01-01

Background Clinical trials of Chimeric Antigen Receptor (CAR) T cells manufactured from autologous peripheral blood mononuclear cell (PBMC) concentrates for the treatment of hematologic malignancies have been promising, but CAR T cell yields have been variable. This variability is due in part to the contamination of the PBMC concentrates with monocytes and granulocytes. Methods Counter-flow elutriation allows for the closed system separation of lymphocytes from monocytes and granulocytes. We ...

Redirecting T cells to eradicate B-cell acute lymphoblastic leukemia: bispecific T-cell engagers and chimeric antigen receptors.

Science.gov (United States)

Aldoss, I; Bargou, R C; Nagorsen, D; Friberg, G R; Baeuerle, P A; Forman, S J

2017-04-01

Recent advances in antibody technology to harness T cells for cancer immunotherapy, particularly in the difficult-to-treat setting of relapsed/refractory acute lymphoblastic leukemia (r/r ALL), have led to innovative methods for directing cytotoxic T cells to specific surface antigens on cancer cells. One approach involves administration of soluble bispecific (or dual-affinity) antibody-based constructs that temporarily bridge T cells and cancer cells. Another approach infuses ex vivo-engineered T cells that express a surface plasma membrane-inserted antibody construct called a chimeric antigen receptor (CAR). Both bispecific antibodies and CARs circumvent natural target cell recognition by creating a physical connection between cytotoxic T cells and target cancer cells to activate a cytolysis signaling pathway; this connection allows essentially all cytotoxic T cells in a patient to be engaged because typical tumor cell resistance mechanisms (such as T-cell receptor specificity, antigen processing and presentation, and major histocompatibility complex context) are bypassed. Both the bispecific T-cell engager (BiTE) antibody construct blinatumomab and CD19-CARs are immunotherapies that have yielded encouraging remission rates in CD19-positive r/r ALL, suggesting that they might serve as definitive treatments or bridging therapies to allogeneic hematopoietic cell transplantation. With the introduction of these immunotherapies, new challenges arise related to unique toxicities and distinctive pathways of resistance. An increasing body of knowledge is being accumulated on how to predict, prevent, and manage such toxicities, which will help to better stratify patient risk and tailor treatments to minimize severe adverse events. A deeper understanding of the precise mechanisms of action and immune resistance, interaction with other novel agents in potential combinations, and optimization in the manufacturing process will help to advance immunotherapy outcomes in the r

Insulin-like growth factor I reduces lipid oxidation and foam cell formation via downregulation of 12/15-lipoxygenase.

Science.gov (United States)

Sukhanov, Sergiy; Snarski, Patricia; Vaughn, Charlotte; Lobelle-Rich, Patricia; Kim, Catherine; Higashi, Yusuke; Shai, Shaw-Yung; Delafontaine, Patrice

2015-02-01

We have shown that insulin-like growth factor I (IGF-1) infusion in Apoe(-/-) mice decreased atherosclerotic plaque size and plaque macrophage and lipid content suggesting that IGF-1 suppressed formation of macrophage-derived foam cells. Since 12/15-lipoxygenase (12/15-LOX) plays an important role in OxLDL and foam cell formation, we hypothesized that IGF-1 downregulates 12/15-LOX, thereby suppressing lipid oxidation and foam cell formation. We found that IGF-1 decreased 12/15-LOX plaque immunopositivity and serum OxLDL levels in Apoe(-/-) mice. IGF-1 reduced 12/15-LOX protein and mRNA levels in cultured THP-1 macrophages and IGF-1 also decreased expression of STAT6 transcription factor. IGF-1 reduction in macrophage 12/15-LOX was mediated in part via a PI3 kinase- and STAT6-dependent transcriptional mechanism. IGF-1 suppressed THP-1 macrophage ability to oxidize lipids and form foam cells. IGF-1 downregulated 12/15-LOX in human blood-derived primary macrophages and IGF-1 decreased LDL oxidation induced by these cells. IGF-1 reduced LDL oxidation and formation of foam cells by wild type murine peritoneal macrophages, however these effects were completely blocked in 12/15-LOX-null macrophages suggesting that the ability of IGF-1 to reduce LDL oxidation and foam cells formation is dependent on its ability to downregulate 12/15-LOX. Overall our data demonstrate that IGF-1 reduces lipid oxidation and foam cell formation via downregulation of 12/15-LOX and this mechanism may play a major role in the anti-atherosclerotic effects of IGF-1. Published by Elsevier Ireland Ltd.

Insulin-like Growth Factor I Reduces Lipid Oxidation and Foam Cell Formation via Downregulation of 12/15-lipoxygenase

Science.gov (United States)

Sukhanov, Sergiy; Snarski, Patricia; Vaughn, Charlotte; Lobelle-Rich, Patricia; Kim, Catherine; Higashi, Yusuke; Shai, Shaw-Yung; Delafontaine, Patrice

2014-01-01

Objective We have shown that insulin-like growth factor I (IGF-1) infusion in Apoe−/− mice decreased atherosclerotic plaque size and plaque macrophage and lipid content suggesting that IGF-1 suppressed formation of macrophage-derived foam cells. Since 12/15-lipoxygenase (12/15-LOX) plays an important role in OxLDL and foam cell formation, we hypothesized that IGF-1 downregulates 12/15-LOX, thereby suppressing lipid oxidation and foam cell formation. Approach and Results We found that IGF-1 decreased 12/15-LOX plaque immunopositivity and serum OxLDL levels in Apoe−/− mice. IGF-1 reduced 12/15-LOX protein and mRNA levels in cultured THP-1 macrophages and IGF-1 also decreased expression of STAT6 transcription factor. IGF-1 reduction in macrophage 12/15-LOX was mediated in part via a PI3 kinase- and STAT6-dependent transcriptional mechanism. IGF-1 suppressed THP-1 macrophage ability to oxidize lipids and form foam cells. IGF-1 downregulated 12/15-LOX in human blood-derived primary macrophages and IGF-1 decreased LDL oxidation induced by these cells. IGF-1 reduced LDL oxidation and formation of foam cells by wild type murine peritoneal macrophages, however these effects were completely blocked in 12/15-LOX-null macrophages suggesting that the ability of IGF-1 to reduce LDL oxidation and foam cells formation is dependent on its ability to downregulate 12/15-LOX. Conclusions Overall our data demonstrate that IGF-1 reduces lipid oxidation and foam cell formation via downregulation of 12/15-LOX and this mechanism may play a major role in the anti-atherosclerotic effects of IGF-1. PMID:25549319

Memory control by the B cell antigen receptor.

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Engels, Niklas; Wienands, Jürgen

2018-05-01

The generation of memory B cells (MBCs) that have undergone immunoglobulin class switching from IgM, which dominates primary antibody responses, to other immunoglobulin isoforms is a hallmark of immune memory. Hence, humoral immunological memory is characterized by the presence of serum immunoglobulins of IgG subtypes known as the γ-globulin fraction of blood plasma proteins. These antibodies reflect the antigen experience of B lymphocytes and their repeated triggering. In fact, efficient protection against a previously encountered pathogen is critically linked to the production of pathogen-specific IgG molecules even in those cases where the primary immune response required cellular immunity, for example, T cell-mediated clearance of intracellular pathogens such as viruses. Besides IgG, also IgA and IgE can provide humoral immunity depending on the microbe's nature and infection route. The molecular mechanisms underlying the preponderance of switched immunoglobulin isotypes during memory antibody responses are a matter of active and controversial debate. Here, we summarize the phenotypic characteristics of distinct MBC subpopulations and discuss the decisive roles of different B cell antigen receptor isotypes for the functional traits of class-switched B cell populations. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Generation and characterization of antigenic variants induced by exposure of tumor cells to UV radiation in vitro

International Nuclear Information System (INIS)

Hostetler, L.L.W.

1988-01-01

Antigenic changes present in nonantigenic tumor cells exposed to UV radiation (UV) in vitro were investigated by addressing the following questions: (1) Are antigenic variants (AV) produced that are rejected in normal but not immunosuppressed mice? (2) Does generation of AV depend upon intrinsic properties of the cells exposed or result from the action of UV? (3) Is antigenic modification induced by UV due to increased histocompatibility antigen expression? (4) Do AV crossreact immunologically with parental tumor or with other AV? and (5) Is the UV-associated common antigen expressed on UV-induced tumors present on UV-irradiated tumor cells? AV were generated at different frequencies following in vitro UV irradiation of a spontaneous murine fibrosarcoma, a murine melanoma, and two melanoma clones. Immunological experiments demonstrated that the AV and parental cells shared a determinant that was susceptible to immune recognition, but incapable of inducing immunity. In contrast, the AV were noncrossreactive, suggesting that variant-specific antigens were also expressed. Finally, the AV were recognized by UV-induced suppressor cells, indicating that the UV-associated common antigen expressed by UV-induced tumors was also present

Down-regulation of human endogenous retrovirus type K (HERV-K) viral env RNA in pancreatic cancer cells decreases cell proliferation and tumor growth

Science.gov (United States)

Li, Ming; Radvanyi, Laszlo; Yin, Bingnan; Li, Jia; Chivukula, Raghavender; Lin, Kevin; Lu, Yue; Shen, JianJun; Chang, David Z.; Li, Donghui; Johanning, Gary L.; Wang-Johanning, Feng

2017-01-01

Purpose We investigated the role of the human endogenous retrovirus type K (HERV-K) envelope (env) gene in pancreatic cancer (PC). Experimental Design shRNA was employed to knockdown (KD) the expression of HERV-K in PC cells. Results HERV-K env expression was detected in seven PC cell lines and in 80% of PC patient biopsies, but not in two normal pancreatic cell lines or uninvolved normal tissues. A new HERV-K splice variant was discovered in several PC cell lines. RT activity and virus-like particles were observed in culture media supernatant obtained from Panc-1 and Panc-2 cells. HERV-K viral RNA levels and anti-HERV-K antibody titers were significantly higher in PC patient sera (N=106) than in normal donor sera (N=40). Importantly, the in vitro and in vivo growth rates of three PC cell lines were significantly reduced after HERV-K KD by shRNA targeting HERV-K env, and there was reduced metastasis to lung after treatment. RNA-seq results revealed changes in gene expression after HERV-K env KD, including RAS and TP53. Furthermore, downregulation of HERV-K Env protein expression by shRNA also resulted in decreased expression of RAS, p-ERK, p-RSK, and p-AKT in several PC cells or tumors. Conclusion These results demonstrate that HERV-K influences signal transduction via the RAS-ERK-RSK pathway in PC. Our data highlight the potentially important role of HERV-K in tumorigenesis and progression of PC, and indicate that HERV-K viral proteins may be attractive biomarkers and/or tumor-associated antigens, as well as potentially useful targets for detection, diagnosis and immunotherapy of PC. PMID:28679769

Antigen entrapped in the escheriosomes leads to the generation of CD4(+) helper and CD8(+) cytotoxic T cell response.

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Syed, Faisal M; Khan, Masood A; Nasti, Tahseen H; Ahmad, Nadeem; Mohammad, Owais

2003-06-02

In previous study, we demonstrated the potential of Escherichia coli (E. coli) lipid liposomes (escheriosomes) to undergo membrane-membrane fusion with cytoplasmic membrane of the target cells including professional antigen presenting cells. Our present study demonstrates that antigen encapsulated in escheriosomes could be successfully delivered simultaneously to the cytosolic as well as endosomal processing pathways of antigen presenting cells, leading to the generation of both CD4(+) T-helper and CD8(+) cytotoxic T cell response. In contrast, encapsulation of same antigen in egg phosphatidyl-choline (egg PC) liposomes, just like antigen-incomplete Freund's adjuvant (IFA) complex, has inefficient access to the cytosolic pathway of MHC I-dependent antigen presentation and failed to generate antigen-specific CD8(+) cytotoxic T cell response. However, both egg PC liposomes as well as escheriosomes-encapsulated antigen elicited strong humoral immune response in immunized animals but antibody titre was significantly higher in the group of animals immunized with escheriosomes-encapsulated antigen. These results imply usage of liposome-based adjuvant as potential candidate vaccine capable of eliciting both cell-mediated as well as humoral immune responses. Furthermore, antigen entrapped in escheriosomes stimulates antigen-specific CD4(+) T cell proliferation and also enhances the level of IL-2, IFN-gamma and IL-4 in the immunized animals.

Cell-mediated immune response of synovial fluid lymphocytes to ureaplasma antigen in Reiter's syndrome

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Pavlica Ljiljana

2003-01-01

Full Text Available INTRODUCTION Reiter's syndrome (RS is an seronegative arthritis that occurs after urogenital or enteric infection which in addition with occular and/or mucocutaneous manifestations presents complete form of disease. According to previous understanding arthritis in the RS is the reactive one, which means that it is impossible to isolate its causative agent. However, there are the more and more authors suggesting that arthritis in the urogenital form of disease is caused by the infective agent in the affected joint. This suggestion is based on numerous studies on the presence of Chlmaydia trachomatis and Ureaplasma urealyticum in the inflamed joint by using new diagnostic methods in molecular biology published in the recent literature [1-3]. Besides, numerous studies of the humoral and cell-mediated immune response to "triggering" bacteria in the affected joint have supported previous suggestions [4-7]. Aim of the study was to determine whether synovial fluid T-cells specifically recognize the "triggering" bacteria presumably responsible for the Reiter's syndrome. METHOD The 3H-thymidine uptake procedure for measuring lymphocyte responses was applied to lymphocytes derived concurrently from synovial fluid (SF and from peripheral blood (PB [8]. Ureaplasma antigen and mitogen PHA stimulated lymphocytes in 24 RS patients (24 PB samples, 9 SF samples and the results were compared with those found in 10 patients with rheumatoid arthritis (RA (10 PB samples, 5 SF samples. Preparation of ureaplasma antigen. Ureaplasma was cultured on cell-free liquid medium [9]. Sample of 8 ml was heat-inactivated for 15 minutes at 601C and permanently stirred with magnetic mixer. The sample was centrifuged at 2000 x g for 40 minutes and than deposits carefully carried to other sterile glass tubes (Corex and recentrifuged at 9000 x g for 30 minutes. The deposit was washed 3 times in sterile 0.9% NaCl, and final sediment was resuspended in 1.2 ml sterile 0.9% Na

Molecular effects of bioactive fraction of Curcuma mangga (DLBS4847) as a downregulator of 5α-reductase activity pathways in prostatic epithelial cells

International Nuclear Information System (INIS)

Karsono, Agung Heru; Tandrasasmita, Olivia Mayasari; Tjandrawinata, Raymond R

2014-01-01

DLBS4847 is a standardized bioactive fraction of Curcuma mangga. In this study, we used prostate cancer (PC)-3 as the cell line to study the effects of DLBS4847 on prostatic cell viability, as well as related molecular changes associated with the decreased cell number. The observation revealed that DLBS4847 inhibited the growth of PC3 cells through downregulation of the 5α-reductase (5AR) pathway. At the transcription level, 5AR1 and androgen-receptor gene expressions were downregulated in a dose-dependent manner. Furthermore, 5AR-1 and dihydrotestosterone expression were also downregulated at the protein level. A microarray study was also performed to see the effects of DLBS4847 on differential gene expressions in prostate cancer 3 cells. Among others, DLBS4847 downregulated genes related to prostate growth and hypertrophy. Our results suggested that DLBS4847 could potentially become an alternative treatment for prostate disorders, such as benign prostatic hyperplasia. In this regard, DLBS4847 exerts its growth inhibition partially through downregulation of the 5AR pathway

Mechanical Stress Downregulates MHC Class I Expression on Human Cancer Cell Membrane

DEFF Research Database (Denmark)

La Rocca, Rosanna; Tallerico, Rossana; Hassan, Almosawy Talib

2014-01-01

In our body, cells are continuously exposed to physical forces that can regulate different cell functions such as cell proliferation, differentiation and death. In this work, we employed two different strategies to mechanically stress cancer cells. The cancer and healthy cell populations were...... treated either with mechanical stress delivered by a micropump (fabricated by deep X-ray nanolithography) or by ultrasound wave stimuli. A specific down-regulation of Major Histocompatibility Complex (MHC) class I molecules expression on cancer cell membrane compared to different kinds of healthy cells...... between 700–1800 cm-1, indicated a relative concentration variation of MHC class I. PCA analysis was also performed to distinguish control and stressed cells within different cell lines. These mechanical induced phenotypic changes increase the tumor immunogenicity, as revealed by the related increased...

A novel system of artificial antigen-presenting cells efficiently stimulates Flu peptide-specific cytotoxic T cells in vitro

International Nuclear Information System (INIS)

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

2011-01-01

Highlights: → Adoptive immunotherapy depends on relevant numbers of cytolytic T lymphocytes. → An ideal artificial APCs system was successfully prepared in vivo. → Controlled release of IL-2 leads to much more T-cell expansion. → 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.

A novel system of artificial antigen-presenting cells efficiently stimulates Flu peptide-specific cytotoxic T cells in vitro

Energy Technology Data Exchange (ETDEWEB)

Han, Hui [Department of Hepatobiliary Surgery, Peking University People' s Hospital, Beijing 100044 (China); Peng, Ji-Run, E-mail: pengjr@medmail.com.cn [Department of Hepatobiliary Surgery, Peking University People' s Hospital, Beijing 100044 (China); Chen, Peng-Cheng; Gong, Lei [Department of Hepatobiliary Surgery, Peking University People' s Hospital, Beijing 100044 (China); Qiao, Shi-Shi [Department of Hepatobiliary Surgery, The First Affiliated Hospital, Zhengzhou University, Zhengzhou 450052 (China); Wang, Wen-Zhen; Cui, Zhu-Qingqing; Yu, Xin; Wei, Yu-Hua [Department of Hepatobiliary Surgery, Peking University People' s Hospital, Beijing 100044 (China); Leng, Xi-Sheng, E-mail: lengxs2003@yahoo.com.cn [Department of Hepatobiliary Surgery, Peking University People' s Hospital, Beijing 100044 (China)

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.

Antigen-Addicted T Cell Reserves Trickle Charge the Frontline Killers.

Science.gov (United States)

Kalia, Vandana; Sarkar, Surojit

2016-07-19

Highly active killer T cells mediate a stable standoff during controlled persistent infections. In this issue of Immunity, Robey and colleagues describe a unique antigen-addicted T cell population bearing characteristics of both effector and memory CD8(+) T cells that provides a continuous supply of potent killer T cells to curb Toxoplasma gondii growth during latency. Copyright © 2016 Elsevier Inc. All rights reserved.

Modification of T-cell antigenic properties of tetanus toxoid by SDS-PAGE separation. Implications for T-cell blotting

DEFF Research Database (Denmark)

Christensen, C B; Theander, T G

1997-01-01

Using Tetanus Toxoid (TT) as a model antigen the T-cell Blotting method was evaluated. Peripheral blood mononuclear cell (PBMC) cultures were stimulated by blotted nitrocellulose-bound TT or soluble TT. SDS-Poly-Acrylamide-Gel-Electrophoresis separated TT only induced proliferation in 20% of the ......Using Tetanus Toxoid (TT) as a model antigen the T-cell Blotting method was evaluated. Peripheral blood mononuclear cell (PBMC) cultures were stimulated by blotted nitrocellulose-bound TT or soluble TT. SDS-Poly-Acrylamide-Gel-Electrophoresis separated TT only induced proliferation in 20......% of the PBMC cultures whereas proliferation was induced in 79% of the same cultures offered similar treated TT (except for the PAGE separation). When T-cell blotting was performed with TT separated in a SDS-agarose matrix, proliferation was induced in 80% of donors responding to soluble TT. The results show...... that SDS-PAGE alters the ability of TT to induce T-cell proliferation, possibly due to unpolymerized acrylamide binding to proteins during SDS-PAGE. The use of SDS-PAGE T-cell blotting in the screening for T-cell antigens must therefore be reconsidered. We suggest the use of SDS-Agarose Gel Electrophoresis...

Manufacture of clinical-grade CD19-specific T cells stably expressing chimeric antigen receptor using Sleeping Beauty system and artificial antigen presenting cells.

Directory of Open Access Journals (Sweden)

Harjeet Singh

Full Text Available 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 ∼10(10 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.

Suppressor cells in transplantation tolerance. III. The role of antigen in the maintenance of transplantation tolerance

International Nuclear Information System (INIS)

Tutschka, P.J.; Hess, A.D.; Beschorner, W.E.; Santos, G.W.

1982-01-01

Suppressor cells, which in an alloantigen-specific manner inhibit proliferation of donor cells to host antigens in a mixed lymphocyte culture and adoptively transfer the suppression of graft-versus-host disease (GVHD), undergo a gradual clonal reduction in long-term, allogeneic, histoincompatible rat radiation chimeras until they can no longer be measured in an in vitro suppressor cell assay. When lymphohematopoietic cells from these chimeras are transferred into lethally irradiated secondary recipients of original donor strain, the suppressor cells, now in a target antigen-free environment, undergo a further clonal reduction. After parking for 120 days, the chimeric cells are specifically tolerant to original host antigens, but cannot adoptively transfer suppression of GVHD. When chimeric cells, parked for 120 days in secondary recipients of original donor strain, are stimulated with original host-type antigen repeatedly during or once at the end of the parking period, the suppressor cell clone is expanded, suppressor cells can be identified in vitro, and suppression of GVHD can adoptively be transferred to tertiary recipients

Leukemia-associated antigens in man.

Science.gov (United States)

Brown, G; Capellaro, D; Greaves, M

1975-12-01

Rabbit antisera raised against acute lymphoblastic leukemia (ALL) cells were used to distinguish ALL from other leukemias, to identify rare leukemia cells in the bone marrow of patients in remission, and to define human leukemia-associated antigens. Antibody binding was studied with the use of immunofluorescence reagents and the analytic capacity of the Fluorescence Activated Cell Sorter-1 (FACS-1). The results indicated that most non-T-cell ALL have three leukemia-associated antigens on their surface which are absent from normal lymphoid cells: 1) an antigen shared with myelocytes, myeloblastic leukemia cells, and fetal liver (hematopoietic) cells; 2) an antigen shared with a subset of intermediate normoblasts in normal bone marrow and fetal liver; and 3) an antigen found thus far only on non-T-cell ALL and in some acute undifferentiated leukemias, which we therefore regard as a strong candidate for a leukemia-specific antigen. These antigens are absent from a subgroup of ALL patients in which the lymphoblasta express T-cell surface markers. Preliminary studies on the bone marrow samples of patients in remission indicated that rare leukemia cells were present in some samples. The implications of these findings with respect to the heterogeneity and cell origin(s) of ALL, its diagnosis, and its potential monitoring during treatment were discussed.

Reduced response to Epstein–Barr virus antigens by T-cells in systemic lupus erythematosus patients

Science.gov (United States)

Draborg, Anette Holck; Jacobsen, Søren; Westergaard, Marie; Mortensen, Shila; Larsen, Janni Lisander; Houen, Gunnar; Duus, Karen

2014-01-01

Objective Epstein–Barr virus (EBV) has for long been associated with systemic lupus erythematosus (SLE). In this study, we investigated the levels of latent and lytic antigen EBV-specific T-cells and antibodies in SLE patients. Methods T cells were analyzed by flow cytometry and antibodies were analyzed by enzyme-linked immunosorbent assay. Results SLE patients showed a significantly reduced number of activated (CD69) T-cells upon ex vivo stimulation with EBV nuclear antigen (EBNA) 1 or EBV early antigen diffuse (EBV-EA/D) in whole blood samples compared with healthy controls. Also, a reduced number of T-cells from SLE patients were found to produce interferon-γ upon stimulation with these antigens. Importantly, responses to a superantigen were normal in SLE patients. Compared with healthy controls, SLE patients had fewer EBV-specific T-cells but higher titres of antibodies against EBV. Furthermore, an inverse correlation was revealed between the number of lytic antigen EBV-specific T-cells and disease activity of the SLE patients, with high-activity SLE patients having fewer T-cells than low-activity SLE patients. Conclusions These results indicate a limited or a defective EBV-specific T-cell response in SLE patients, which may suggest poor control of EBV infection in SLE with an immune reaction shift towards a humoral response in an attempt to control viral reactivation. A role for decreased control of EBV as a contributing agent in the development or exacerbation of SLE is proposed. PMID:25396062

How to train your T cell: genetically engineered chimeric antigen receptor T cells versus bispecific T-cell engagers to target CD19 in B acute lymphoblastic leukemia.

Science.gov (United States)

Ruella, Marco; Gill, Saar

2015-06-01

Antigen-specific T cell-based immunotherapy is getting its day in the sun. The contemporaneous development of two potent CD19-specific immunotherapeutic modalities for the treatment of B-cell malignancies provides exciting opportunities for patients, physicians and scientists alike. Patients with relapsed, refractory or poor-risk B-cell acute lymphoblastic leukemia (ALL) previously had few therapeutic options and now have two potential new lifelines. Physicians will have the choice between two powerful modalities and indeed could potentially enroll some patients on trials exploring both modalities if needed. For scientists interested in tumor immunology, the advent of chimeric antigen receptor T-cell therapy and of bispecific T-cell engagers (BiTEs) provides unprecedented opportunities to explore the promise and limitations of antigen-specific T-cell therapy in the context of human leukemia. In this article, we compare chimeric antigen receptor T cells and BiTEs targeting CD19 in B-cell ALL in the setting of the available clinical literature.

Adsorption of multimeric T cell antigens on carbon nanotubes

DEFF Research Database (Denmark)

Fadel, Tarek R; Li, Nan; Shah, Smith

2013-01-01

Antigen-specific activation of cytotoxic T cells can be enhanced up to three-fold more than soluble controls when using functionalized bundled carbon nanotube substrates ((b) CNTs). To overcome the denaturing effects of direct adsorption on (b) CNTs, a simple but robust method is demonstrated...... to stabilize the T cell stimulus on carbon nanotube substrates through non-covalent attachment of the linker neutravidin....

[Expression changes of major outer membrane protein antigens in Leptospira interrogans during infection and its mechanism].

Science.gov (United States)

Zheng, Linli; Ge, Yumei; Hu, Weilin; Yan, Jie

2013-03-01

To determine expression changes of major outer membrane protein(OMP) antigens of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Lai strain Lai during infection of human macrophages and its mechanism. OmpR encoding genes and OmpR-related histidine kinase (HK) encoding gene of L.interrogans strain Lai and their functional domains were predicted using bioinformatics technique. mRNA level changes of the leptospiral major OMP-encoding genes before and after infection of human THP-1 macrophages were detected by real-time fluorescence quantitative RT-PCR. Effects of the OmpR-encoding genes and HK-encoding gene on the expression of leptospiral OMPs during infection were determined by HK-peptide antiserum block assay and closantel inhibitive assays. The bioinformatics analysis indicated that LB015 and LB333 were referred to OmpR-encoding genes of the spirochete, while LB014 might act as a OmpR-related HK-encoding gene. After the spirochete infecting THP-1 cells, mRNA levels of leptospiral lipL21, lipL32 and lipL41 genes were rapidly and persistently down-regulated (P Expression levels of L.interrogans strain Lai major OMP antigens present notable changes during infection of human macrophages. There is a group of OmpR-and HK-encoding genes which may play a major role in down-regulation of expression levels of partial OMP antigens during infection.

Improved Activation toward Primary Colorectal Cancer Cells by Antigen-Specific Targeting Autologous Cytokine-Induced Killer Cells

Directory of Open Access Journals (Sweden)

Claudia Schlimper

2012-01-01

Full Text Available Adoptive therapy of malignant diseases with cytokine-induced killer (CIK cells showed promise in a number of trials; the activation of CIK cells from cancer patients towards their autologous cancer cells still needs to be improved. Here, we generated CIK cells ex vivo from blood lymphocytes of colorectal cancer patients and engineered those cells with a chimeric antigen receptor (CAR with an antibody-defined specificity for carcinoembryonic antigen (CEA. CIK cells thereby gained a new specificity as defined by the CAR and showed increase in activation towards CEA+ colon carcinoma cells, but less in presence of CEA− cells, indicated by increased secretion of proinflammatory cytokines. Redirected CIK activation was superior by CAR-mediated CD28-CD3ζ than CD3ζ signaling only. CAR-engineered CIK cells from colon carcinoma patients showed improved activation against their autologous, primary carcinoma cells from biopsies resulting in more efficient tumour cell lysis. We assume that adoptive therapy with CAR-modified CIK cells shows improved selectivity in targeting autologous tumour lesions.

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

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Botros B. Shenoda

2016-01-01

Full Text Available 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.

Epigenetic modulation of cancer-germline antigen gene expression in tumorigenic human mesenchymal stem cells: implications for cancer therapy

DEFF Research Database (Denmark)

Gjerstorff, Morten; Burns, Jorge S; Nielsen, Ole

2009-01-01

Cancer-germline antigens are promising targets for cancer immunotherapy, but whether such therapies will also eliminate the primary tumor stem cell population remains undetermined. We previously showed that long-term cultures of telomerized adult human bone marrow mesenchymal stem cells can...... spontaneously evolve into tumor-initiating, mesenchymal stem cells (hMSC-TERT20), which have characteristics of clinical sarcoma cells. In this study, we used the hMSC-TERT20 tumor stem cell model to investigate the potential of cancer-germline antigens to serve as tumor stem cell targets. We found...... of cancer-germline antigens in hMSC-TERT20 cells, while their expression levels in primary human mesenchymal stem cells remained unaffected. The expression pattern of cancer-germline antigens in tumorigenic mesenchymal stem cells and sarcomas, plus their susceptibility to enhancement by epigenetic...

Downregulated TIPE2 is associated with poor prognosis and promotes cell proliferation in non-small cell lung cancer

International Nuclear Information System (INIS)

Li, Yuexia; Li, Xiaohui; Liu, Gang; Sun, Rongqing; Wang, Lirui; Wang, Jing; Wang, Hongmin

2015-01-01

Highlights: • TIPE2 is down-regulated in NSCLC tissues. • TIPE2 inhibits NSCLC cell proliferation, colony formation and invasion. • TIPE2 reduces the anti-apoptotic Bcl-XL protein and mesenchymal marker N-cadherin expression. - Abstract: The present study aims to investigate the expression pattern of TIPE2 protein and its clinical significance in human non-small cell lung cancer (NSCLC). We investigated the expression levels of TIPE2 in 96 NSCLC tumor samples by immunohistochemistry and then analyzed its clinical significance. Furthermore, the role of TIPE2 on the biological properties of the NSCLC cell line H1299 and A549 was experimentally tested in vitro and in vivo. We found that the expression level of TIPE2 was significantly higher in normal lung tissues compared with NSCLC tissues (P < 0.001), and TIPE2 downregulation was significantly correlated with advanced TNM stage (P = 0.006). TIPE2 expression was lower in lung cancer cell lines than normal bronchial cell line HBE. Transfection of TIPE2 plasmid was performed in H1299 and A549 cells. TIPE2 overexpression inhibited lung cancer cell proliferation, colony formation and cell invasive in vitro, and prevented lung tumor growth in vivo. In addition, TIPE2 transfection reduced the anti-apoptotic Bcl-XL protein and mesenchymal marker N-cadherin expression. Taken together, our results demonstrate that TIPE2 might serve as a tumor suppressor in NSCLC progression

Downregulated TIPE2 is associated with poor prognosis and promotes cell proliferation in non-small cell lung cancer

Energy Technology Data Exchange (ETDEWEB)

Li, Yuexia [Intensive Care Unit, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052 (China); Li, Xiaohui [Department of Cardiovascular Surgery, Henan Provincial People’s Hospital, Zhengzhou, Henan 450003 (China); Liu, Gang; Sun, Rongqing; Wang, Lirui [Intensive Care Unit, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052 (China); Wang, Jing, E-mail: jing_wang1980@163.com [Department of Respiratory Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052 (China); Wang, Hongmin, E-mail: hmwangzz@126.com [Department of Respiratory Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052 (China)

2015-01-30

Highlights: • TIPE2 is down-regulated in NSCLC tissues. • TIPE2 inhibits NSCLC cell proliferation, colony formation and invasion. • TIPE2 reduces the anti-apoptotic Bcl-XL protein and mesenchymal marker N-cadherin expression. - Abstract: The present study aims to investigate the expression pattern of TIPE2 protein and its clinical significance in human non-small cell lung cancer (NSCLC). We investigated the expression levels of TIPE2 in 96 NSCLC tumor samples by immunohistochemistry and then analyzed its clinical significance. Furthermore, the role of TIPE2 on the biological properties of the NSCLC cell line H1299 and A549 was experimentally tested in vitro and in vivo. We found that the expression level of TIPE2 was significantly higher in normal lung tissues compared with NSCLC tissues (P < 0.001), and TIPE2 downregulation was significantly correlated with advanced TNM stage (P = 0.006). TIPE2 expression was lower in lung cancer cell lines than normal bronchial cell line HBE. Transfection of TIPE2 plasmid was performed in H1299 and A549 cells. TIPE2 overexpression inhibited lung cancer cell proliferation, colony formation and cell invasive in vitro, and prevented lung tumor growth in vivo. In addition, TIPE2 transfection reduced the anti-apoptotic Bcl-XL protein and mesenchymal marker N-cadherin expression. Taken together, our results demonstrate that TIPE2 might serve as a tumor suppressor in NSCLC progression.

T cells targeting a neuronal paraneoplastic antigen mediate tumor rejection and trigger CNS autoimmunity with humoral activation.

Science.gov (United States)

Blachère, Nathalie E; Orange, Dana E; Santomasso, Bianca D; Doerner, Jessica; Foo, Patricia K; Herre, Margaret; Fak, John; Monette, Sébastien; Gantman, Emily C; Frank, Mayu O; Darnell, Robert B

2014-11-01

Paraneoplastic neurologic diseases (PND) involving immune responses directed toward intracellular antigens are poorly understood. Here, we examine immunity to the PND antigen Nova2, which is expressed exclusively in central nervous system (CNS) neurons. We hypothesized that ectopic expression of neuronal antigen in the periphery could incite PND. In our C57BL/6 mouse model, CNS antigen expression limits antigen-specific CD4+ and CD8+ T-cell expansion. Chimera experiments demonstrate that this tolerance is mediated by antigen expression in nonhematopoietic cells. CNS antigen expression does not limit tumor rejection by adoptively transferred transgenic T cells but does limit the generation of a memory population that can be expanded upon secondary challenge in vivo. Despite mediating cancer rejection, adoptively transferred transgenic T cells do not lead to paraneoplastic neuronal targeting. Preliminary experiments suggest an additional requirement for humoral activation to induce CNS autoimmunity. This work provides evidence that the requirements for cancer immunity and neuronal autoimmunity are uncoupled. Since humoral immunity was not required for tumor rejection, B-cell targeting therapy, such as rituximab, may be a rational treatment option for PND that does not hamper tumor immunity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stem Cell Antigen-1 in Skeletal Muscle Function

OpenAIRE

Bernstein, Harold S.; Samad, Tahmina; Cholsiripunlert, Sompob; Khalifian, Saami; Gong, Wenhui; Ritner, Carissa; Aurigui, Julian; Ling, Vivian; Wilschut, Karlijn J.; Bennett, Stephen; Hoffman, Julien; Oishi, Peter

2013-01-01

Stem cell antigen-1 (Sca-1) is a member of the Ly-6 multigene family encoding highly homologous, glycosyl-phosphatidylinositol-anchored membrane proteins. Sca-1 is expressed on muscle-derived stem cells and myogenic precursors recruited to sites of muscle injury. We previously reported that inhibition of Sca-1 expression stimulated myoblast proliferation in vitro and regulated the tempo of muscle repair in vivo. Despite its function in myoblast expansion during muscle repair, a role for Sca-1...

Tumor-Derived Microvesicles Modulate Antigen Cross-Processing via Reactive Oxygen Species-Mediated Alkalinization of Phagosomal Compartment in Dendritic Cells

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Federico Battisti

2017-09-01

Full Text Available Dendritic cells (DCs are the only antigen-presenting cells able to prime naïve T cells and cross-prime antigen-specific CD8+ T cells. Their functionality is a requirement for the induction and maintenance of long-lasting cancer immunity. Albeit intensively investigated, the in vivo mechanisms underlying efficient antigen cross-processing and presentation are not fully understood. Several pieces of evidence indicate that antigen transfer to DCs mediated by microvesicles (MVs enhances antigen immunogenicity. This mechanism is also relevant for cross-presentation of those tumor-associated glycoproteins such as MUC1 that are blocked in HLA class II compartment when internalized by DCs as soluble molecules. Here, we present pieces of evidence that the internalization of tumor-derived MVs modulates antigen-processing machinery of DCs. Employing MVs derived from ovarian cancer ascites fluid and established tumor cell lines, we show that MV uptake modifies DC phagosomal microenvironment, triggering reactive oxygen species (ROS accumulation and early alkalinization. Indeed, tumor MVs carry radical species and the MV uptake by DCs counteracts the chemically mediated acidification of the phagosomal compartment. Further pieces of evidence suggest that efficacious antigen cross-priming of the MUC1 antigen carried by the tumor MVs results from the early signaling induced by MV internalization and the function of the antigen-processing machinery of DCs. These results strongly support the hypothesis that tumor-derived MVs impact antigen immunogenicity by tuning the antigen-processing machinery of DCs, besides being carrier of tumor antigens. Furthermore, these findings have important implications for the exploitation of MVs as antigenic cell-free immunogen for DC-based therapeutic strategies.

Role of antigen in migration patterns of T cell subsets arising from gut-associated lymphoid tissue

International Nuclear Information System (INIS)

Dunkley, M.L.; Husband, A.J.

1989-01-01

Studies of the migration of antigen-specific regulatory T cell subsets responding to gut immunization were undertaken to clarify their migratory potential and the role of antigen in their localization. In initial experiments, lymphocytes collected from the thoracic duct of rats after immunization of Peyer's patches (PP) with keyhole limpet hemocyanin (KLH), were enriched for T helper (Th) cells and labelled with the fluorochrome H33342. In other experiments, a higher frequency of antigen-specific T cells was achieved by short-term culture of the enriched Th cells in the presence of KLH and the blast cells labelled with 3H-thymidine. The distribution of both populations was determined after injection into immunized and unimmunized syngeneic recipients. Whereas the uncultured population (predominantly small Th cells) localized almost exclusively in follicular lymphoid tissues, the cells expanded by secondary culture (predominantly Th blasts) appeared in the gut lamina propria (LP) initially, then in PP and mesenteric lymph nodes. The Th blasts in the LP were almost always seen in close proximity to the gut epithelium. However, the migration of neither population appeared to be influenced significantly by antigen, in contrast to previous findings with regard to IgA-committed B cells. The initial subepithelial location of Th blasts in the gut LP and their subsequent appearance in PP may provide a mechanism by which antigen presented by epithelial cells could influence B cell differentiation in PP through modulation of signals expressed by these T cells

Role of antigen in migration patterns of T cell subsets arising from gut-associated lymphoid tissue

Energy Technology Data Exchange (ETDEWEB)

Dunkley, M.L.; Husband, A.J. (Univ. of Newcastle, N.S.W. (Australia))

1989-07-01

Studies of the migration of antigen-specific regulatory T cell subsets responding to gut immunization were undertaken to clarify their migratory potential and the role of antigen in their localization. In initial experiments, lymphocytes collected from the thoracic duct of rats after immunization of Peyer's patches (PP) with keyhole limpet hemocyanin (KLH), were enriched for T helper (Th) cells and labelled with the fluorochrome H33342. In other experiments, a higher frequency of antigen-specific T cells was achieved by short-term culture of the enriched Th cells in the presence of KLH and the blast cells labelled with 3H-thymidine. The distribution of both populations was determined after injection into immunized and unimmunized syngeneic recipients. Whereas the uncultured population (predominantly small Th cells) localized almost exclusively in follicular lymphoid tissues, the cells expanded by secondary culture (predominantly Th blasts) appeared in the gut lamina propria (LP) initially, then in PP and mesenteric lymph nodes. The Th blasts in the LP were almost always seen in close proximity to the gut epithelium. However, the migration of neither population appeared to be influenced significantly by antigen, in contrast to previous findings with regard to IgA-committed B cells. The initial subepithelial location of Th blasts in the gut LP and their subsequent appearance in PP may provide a mechanism by which antigen presented by epithelial cells could influence B cell differentiation in PP through modulation of signals expressed by these T cells.

Kinetics of antigen specific and non-specific polyclonal B-cell responses during lethal Plasmodium yoelii malaria

Directory of Open Access Journals (Sweden)

Laurence Rolland

1992-06-01

Full Text Available In order to study the kinetics and composition of the polyclonal B-cell activation associated to malaria infection, antigen-specific and non-specific B-cell responses were evaluated in the spleens of mice infected with Plasmodium yoelii 17 XL or injected with lysed erythrocytes or plasma from P. yoelii infected mice or with P. falciparum culture supernatants. Spleen/body weigth ratio, numbers of nucleated spleen cells and Immunoglobulin-containing and Immunoglobulin-secreting cells increased progressively during the course of infection,in parallel to the parasitemia. A different pattern of kinetics was observed when anti-sheep red blood cell and anti-trinitrophenylated-sheep red blood cell plaque forming cells response were studied: maximum values were observed at early stages of infection, whereas the number of total Immunoglobulin-containing and Immunoglobulin-secreting cells were not yet altered. Conversely, at the end of infection, when these latter values reached their maximum, the anti-sheep red blood cell and anti-trinitrophenylated-sheep red blood cell specific responses were normal or even infranormal. In mice injected with Plasmodium-derived material, a higher increase in antigen-specific PFC was observed, as compared to the increase of Immunoglobulin-containing and Immunoglobulin-secreting cell numbers. This suggested a "preferential" (antigen-plus mitogen-induced stimulation of antigen-specific cells rather than a generalized non-specific (mitogen-induced triggering of B-lymphocytes. On the basis of these and previous results, it is suggested that polyclonal B-cell activation that takes place during the course of infection appears as a result of successive waves of antigen-specific B-cell activation.

A robust and scalable TCR-based reporter cell assay to measure HIV-1 Nef-mediated T cell immune evasion.

Science.gov (United States)

Anmole, Gursev; Kuang, Xiaomei T; Toyoda, Mako; Martin, Eric; Shahid, Aniqa; Le, Anh Q; Markle, Tristan; Baraki, Bemuluyigza; Jones, R Brad; Ostrowski, Mario A; Ueno, Takamasa; Brumme, Zabrina L; Brockman, Mark A

2015-11-01

HIV-1 evades cytotoxic T cell responses through Nef-mediated downregulation of HLA class I molecules from the infected cell surface. Methods to quantify the impact of Nef on T cell recognition typically employ patient-derived T cell clones; however, these assays are limited by the cost and effort required to isolate and maintain primary cell lines. The variable activity of different T cell clones and the limited number of cells generated by re-stimulation can also hinder assay reproducibility and scalability. Here, we describe a heterologous T cell receptor reporter assay and use it to study immune evasion by Nef. Induction of NFAT-driven luciferase following co-culture with peptide-pulsed or virus-infected target cells serves as a rapid, quantitative and antigen-specific measure of T cell recognition of its cognate peptide/HLA complex. We demonstrate that Nef-mediated downregulation of HLA on target cells correlates inversely with T cell receptor-dependent luminescent signal generated by effector cells. This method provides a robust, flexible and scalable platform that is suitable for studies to measure Nef function in the context of different viral peptide/HLA antigens, to assess the function of patient-derived Nef alleles, or to screen small molecule libraries to identify novel Nef inhibitors. Copyright © 2015 Elsevier B.V. All rights reserved.

T cells expressing VHH-directed oligoclonal chimeric HER2 antigen receptors

DEFF Research Database (Denmark)

Jamnani, Fatemeh Rahimi; Rahbarizadeh, Fatemeh; Shokrgozar, Mohammad Ali

2014-01-01

Adoptive cell therapy with engineered T cells expressing chimeric antigen receptors (CARs) originated from antibodies is a promising strategy in cancer immunotherapy. Several unsuccessful trials, however, highlight the need for alternative conventional binding domains and the better combination...

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces Fas-dependent activation-induced cell death in superantigen-primed T cells

Energy Technology Data Exchange (ETDEWEB)

Camacho, Iris A; Nagarkatti, Mitzi [Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298 (United States); Nagarkatti, Prakash S [Department of Pharmacology and Toxicology, PO Box 980613, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298-0613 (United States)

2002-10-01

Immune response against a foreign antigen is characterized by a growth phase, in which antigen-specific T cells clonally expand, followed by a decline phase in which the activated T cells undergo apoptosis, a process termed activation-induced cell death (AICD). In the current study, we have investigated the phase at which 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) acts to downregulate the antigen-specific T cell response. To this end, C57BL/6 +/+ mice were injected with staphylococcal enterotoxin A (SEA) into the footpads (10 {mu}g/footpad), and simultaneously treated with TCDD (10 or 50 {mu}g/kg intraperitoneally). At various time points, the draining lymph node (LN) cells were analyzed for SEA-activated T cells. The data demonstrated that in C57BL/6 +/+ mice, TCDD treatment did not alter the growth phase but facilitated the decline phase of SEA-reactive T cells. TCDD caused a significant decrease in the percentage and absolute numbers of CD4{sup +} and CD8{sup +} SEA-responsive T cells expressing V{beta}3{sup +} and V{beta}11{sup +} but did not affect SEA-nonresponsive V{beta}8{sup +} T cells. Upon in vitro culture, TCDD-exposed SEA-immunized LN cells exhibited increased levels of apoptosis when compared with the vehicle controls. When Fas-deficient (C57BL/6 lpr/lpr) or Fas ligand defective (C57BL/6 gld/gld) mice were treated with TCDD, they failed to exhibit a decrease in percentage and cellularity of SEA-reactive T cells, thereby suggesting a role of Fas-Fas ligand interactions in the TCDD-induced downregulation of SEA-reactive T cell response. The resistance to TCDD-induced decrease in T cell responsiveness to SEA seen in Fas- and FasL-mutant mice was neither due to decreased aryl hydrocabon receptor (AhR) expression nor to altered T cell responsiveness to SEA. The current study demonstrates that TCDD does not prevent T cell activation, but prematurely induces Fas-based AICD, which may contribute to the deletion of antigen-primed T cells. (orig.)

Equine peripheral blood mononuclear cells proliferate in response to tetanus toxoid antigen.

Science.gov (United States)

McKelvie, J; Little, S; Foster, A P; Cunningham, F M; Hamblin, A

1998-01-01

It has been reported that equine peripheral blood mononuclear cells (PBMNs) do not proliferate in response to tetanus toxoid (TT) (Frayne and Stokes 1995, Research in Veterinary Science 59, 79-81). Here we demonstrate that lymphocyte proliferation responses to TT, which are characteristic of a recall antigen, may be achieved under certain culture conditions. Given that TT vaccination is routinely applied to many horses, TT is a suitable antigen for the investigation of cellular immune responses by peripheral blood mononuclear cells in the horse.

[Impact of siRNA-mediated down-regulation of CD147 on human breast cancer cells].

Science.gov (United States)

Li, Zhenqian; Li, Daoming; Li, Jiangwei; Huang, Pei; Qin, Hui

2015-10-01

To investigate the influence of siRNA-mediated down-regulation of CD147 on growth, proliferation and movement of human breast cancer cell line MDA-MB-231. The protein expression of CD147, MMP-2 and TIMP-2 of the MDA-MB-231 cells were analyzed by ABC. Lentiviral expression vector of CD147 gene was constructed and transfected into MDA-MB-231 cells. RT-PCR and Western blot were used to detect the mRNA and protein level changes of CD147 genes to identify the optimal time point, followed by detection of changes of mRNA and protein expression of MMP-2 and TIMP-2 genes. CCK-8 reagent method and cell scratch test were used to detect the proliferation and migration change of MDA-MB-231 cells. The nude mouse model of breast cancer by hypodermic injection with MDA-MB-231 cells was established to document the effect of CD147 siRNA on the tumor transplants. After transfection of lentiviral expression vector of CD147 gene, protein of CD147, MMP-2 and TIMP-2 were weakly or negative expressed, significantly weaker than those of control group (P CD147 and MMP-2 were 96.03% ± 0.84% and 96.03% ± 0.84%, respectively. Both CD147 mRNA and MMP-2 mRNA expression were down-regulated (P 0.05). No less than 2 days after transfection, cell growth of MDA-MB-231 cell line was found significantly inhibited (P CD147 led to reduction of volume and mass of nude mouses. The growth of the carcinoma transplant was inhibited upon siRNA-mediated down-regulation of CD147 (P CD147 may alter the MMP-2/TIMP-2 balance in MDA-MB-231 cells. CD147 gene silencing inhibits the proliferation and migration of MDA-MB-231 cells and the growth of carcinoma transplants in nude mice.

Epstein-Barr virus nuclear antigen 2 specifically induces expression of the B-cell activation antigen CD23

International Nuclear Information System (INIS)

Wang, F.; Gregory, C.D.; Rowe, M.; Rickinson, A.B.; Wang, D.; Birkenbach, M.; Kikutani, H.; Kishimoto, T.; Kieff, E.

1987-01-01

Epstein-Barr virus (EBV) infection of EBV-negative Burkitt lymphoma (BL) cells includes some changes similar to those seen in normal B lymphocytes that have been growth transformed by EBV. The role of individual EBV genes in this process was evaluated by introducing each of the viral genes that are normally expressed in EBV growth-transformed and latently infected lymphoblasts into an EBV-negative BL cell line, using recombinant retrovirus-mediated transfer. Clones of cells were derived that stably express the EBV nuclear antigen 1 (EBNA-1), EBNA-2, EBNA-3, EBNA-leader protein, or EBV latent membrane protein (LMP). These were compared with control clones infected with the retrovirus vector. All 10 clones converted to EBNA-2 expression differed from control clones or clones expressing other EBV proteins by growth in tight clumps and by markedly increased expression of one particular surface marker of B-cell activation, CD23. Other activation antigens were unaffected by EBNA-2 expression, as were markers already expressed on the parent BL cell line. The results indicate that EBNA-2 is a specific direct or indirect trans-activator of CD23. This establishes a link between an EBV gene and cell gene expression. Since CD23 has been implicated in the transduction of B-cell growth signals, its specific induction by EBNA-2 could be important in EBV induction of B-lymphocyte transformation

The actin cytoskeleton modulates the activation of iNKT cells by segregating CD1d nanoclusters on antigen-presenting cells

Science.gov (United States)

Torreno-Pina, Juan A.; Manzo, Carlo; Salio, Mariolina; Aichinger, Michael C.; Oddone, Anna; Lakadamyali, Melike; Shepherd, Dawn; Besra, Gurdyal S.; Cerundolo, Vincenzo

2016-01-01

Invariant natural killer T (iNKT) cells recognize endogenous and exogenous lipid antigens presented in the context of CD1d molecules. The ability of iNKT cells to recognize endogenous antigens represents a distinct immune recognition strategy, which underscores the constitutive memory phenotype of iNKT cells and their activation during inflammatory conditions. However, the mechanisms regulating such “tonic” activation of iNKT cells remain unclear. Here, we show that the spatiotemporal distribution of CD1d molecules on the surface of antigen-presenting cells (APCs) modulates activation of iNKT cells. By using superresolution microscopy, we show that CD1d molecules form nanoclusters at the cell surface of APCs, and their size and density are constrained by the actin cytoskeleton. Dual-color single-particle tracking revealed that diffusing CD1d nanoclusters are actively arrested by the actin cytoskeleton, preventing their further coalescence. Formation of larger nanoclusters occurs in the absence of interactions between CD1d cytosolic tail and the actin cytoskeleton and correlates with enhanced iNKT cell activation. Importantly and consistently with iNKT cell activation during inflammatory conditions, exposure of APCs to the Toll-like receptor 7/8 agonist R848 increases nanocluster density and iNKT cell activation. Overall, these results define a previously unidentified mechanism that modulates iNKT cell autoreactivity based on the tight control by the APC cytoskeleton of the sizes and densities of endogenous antigen-loaded CD1d nanoclusters. PMID:26798067

Correlation between activation of PPAR¿ and resistin downregulation in a mouse adipocyte cell line by a series of thiazolidinediones.

NARCIS (Netherlands)

Sotiriou, A.; Blaauw, R.H.; Meijer, C.; Gijsbers, L.H.; Burg, van der B.; Vervoort, J.; Rietjens, I.M.C.M.

2013-01-01

The present study shows significant correlations between the EC50 for PPAR¿ activation in a reporter gene cell line and resistin downregulation in mouse adipocytes, and between the IC50 for resistin downregulation and the already published minimum effective dose for antihyperglycemic activity in a

Antigen Requirements for Efficient Priming of CD8+ T Cells by Leishmania major-Infected Dendritic Cells

Science.gov (United States)

Bertholet, Sylvie; Debrabant, Alain; Afrin, Farhat; Caler, Elisabeth; Mendez, Susana; Tabbara, Khaled S.; Belkaid, Yasmine; Sacks, David L.

2005-01-01

CD4+ and CD8+ T-cell responses have been shown to be critical for the development and maintenance of acquired resistance to infections with the protozoan parasite Leishmania major. Monitoring the development of immunodominant or clonally restricted T-cell subsets in response to infection has been difficult, however, due to the paucity of known epitopes. We have analyzed the potential of L. major transgenic parasites, expressing the model antigen ovalbumin (OVA), to be presented by antigen-presenting cells to OVA-specific OT-II CD4+ or OT-I CD8+ T cells. Truncated OVA was expressed in L. major as part of a secreted or nonsecreted chimeric protein with L. donovani 3′ nucleotidase (NT-OVA). Dendritic cells (DC) but not macrophages infected with L. major that secreted NT-OVA could prime OT-I T cells to proliferate and release gamma interferon. A diminished T-cell response was observed when DC were infected with parasites expressing nonsecreted NT-OVA or with heat-killed parasites. Inoculation of mice with transgenic parasites elicited the proliferation of adoptively transferred OT-I T cells and their recruitment to the site of infection in the skin. Together, these results demonstrate the possibility of targeting heterologous antigens to specific cellular compartments in L. major and suggest that proteins secreted or released by L. major in infected DC are a major source of peptides for the generation of parasite-specific CD8+ T cells. The ability of L. major transgenic parasites to activate OT-I CD8+ T cells in vivo will permit the analysis of parasite-driven T-cell expansion, differentiation, and recruitment at the clonal level. PMID:16177338

T cell recognition of breast cancer antigens

DEFF Research Database (Denmark)

Petersen, Nadia Viborg; Andersen, Sofie Ramskov; Andersen, Rikke Sick

Recent studies are encouraging research of breast cancer immunogenicity to evaluate the applicability ofimmunotherapy as a treatment strategy. The epitope landscape in breast cancer is minimally described, thus it is necessary to identify T cell targets to develop immune mediated therapies.......This project investigates four proteins commonly upregulated in breast cancer and thus probable tumor associated antigens (TAAs). Aromatase, prolactin, NEK3, and PIAS3 contribute to increase growth, survival, and motility of malignant cells. Aspiring to uncover novel epitopes for cytotoxic T cells, a reverse...... recognition utilizing DNA barcode labeled MHC multimers to screen peripheral blood lymphocytes from breast cancer patients and healthy donor samples. Signif-icantly more TAA specific T cell responses were detected in breast cancer patients than healthy donors for both HLA-A*0201 (P

Mucosal-Associated Invariant T Cells: New Insights into Antigen Recognition and Activation

Directory of Open Access Journals (Sweden)

Xingxing Xiao

2017-11-01

Full Text Available Mucosal-associated invariant T (MAIT cells, a novel subpopulation of innate-like T cells that express an invariant T cell receptor (TCRα chain and a diverse TCRβ chain, can recognize a distinct set of small molecules, vitamin B metabolites, derived from some bacteria, fungi but not viruses, in the context of an evolutionarily conserved major histocompatibility complex-related molecule 1 (MR1. This implies that MAIT cells may play unique and important roles in host immunity. Although viral antigens are not recognized by this limited TCR repertoire, MAIT cells are known to be activated in a TCR-independent mechanism during some viral infections, such as hepatitis C virus and influenza virus. In this article, we will review recent works in MAIT cell antigen recognition, activation and the role MAIT cells may play in the process of bacterial and viral infections and pathogenesis of non-infectious diseases.

Co-stimulatory signaling determines tumor antigen sensitivity and persistence of CAR T cells targeting PSCA+ metastatic prostate cancer.

Science.gov (United States)

Priceman, Saul J; Gerdts, Ethan A; Tilakawardane, Dileshni; Kennewick, Kelly T; Murad, John P; Park, Anthony K; Jeang, Brook; Yamaguchi, Yukiko; Yang, Xin; Urak, Ryan; Weng, Lihong; Chang, Wen-Chung; Wright, Sarah; Pal, Sumanta; Reiter, Robert E; Wu, Anna M; Brown, Christine E; Forman, Stephen J

2018-01-01

Advancing chimeric antigen receptor (CAR)-engineered adoptive T cells for the treatment of solid cancers is a major focus in the field of immunotherapy, given impressive recent clinical responses in hematological malignancies. Prostate cancer may be amenable to T cell-based immunotherapy since several tumor antigens, including prostate stem-cell antigen (PSCA), are widely over-expressed in metastatic disease. While antigen selectivity of CARs for solid cancers is crucial, it is problematic due to the absence of truly restricted tumor antigen expression and potential safety concerns with "on-target off-tumor" activity. Here, we show that the intracellular co-stimulatory signaling domain can determine a CAR's sensitivity for tumor antigen expression. A 4-1BB intracellular co-stimulatory signaling domain in PSCA-CARs confers improved selectivity for higher tumor antigen density, reduced T cell exhaustion phenotype, and equivalent tumor killing ability compared to PSCA-CARs containing the CD28 co-stimulatory signaling domain. PSCA-CARs exhibit robust in vivo anti-tumor activity in patient-derived bone-metastatic prostate cancer xenograft models, and 4-1BB-containing CARs show superior T cell persistence and control of disease compared with CD28-containing CARs. Our study demonstrates the importance of co-stimulation in defining an optimal CAR T cell, and also highlights the significance of clinically relevant models in developing solid cancer CAR T cell therapies.

Co-stimulatory signaling determines tumor antigen sensitivity and persistence of CAR T cells targeting PSCA+ metastatic prostate cancer

Science.gov (United States)

Priceman, Saul J.; Gerdts, Ethan A.; Tilakawardane, Dileshni; Kennewick, Kelly T.; Murad, John P.; Park, Anthony K.; Jeang, Brook; Yamaguchi, Yukiko; Urak, Ryan; Weng, Lihong; Chang, Wen-Chung; Wright, Sarah; Pal, Sumanta; Reiter, Robert E.; Brown, Christine E.; Forman, Stephen J.

2018-01-01

ABSTRACT Advancing chimeric antigen receptor (CAR)-engineered adoptive T cells for the treatment of solid cancers is a major focus in the field of immunotherapy, given impressive recent clinical responses in hematological malignancies. Prostate cancer may be amenable to T cell-based immunotherapy since several tumor antigens, including prostate stem-cell antigen (PSCA), are widely over-expressed in metastatic disease. While antigen selectivity of CARs for solid cancers is crucial, it is problematic due to the absence of truly restricted tumor antigen expression and potential safety concerns with “on-target off-tumor” activity. Here, we show that the intracellular co-stimulatory signaling domain can determine a CAR's sensitivity for tumor antigen expression. A 4-1BB intracellular co-stimulatory signaling domain in PSCA-CARs confers improved selectivity for higher tumor antigen density, reduced T cell exhaustion phenotype, and equivalent tumor killing ability compared to PSCA-CARs containing the CD28 co-stimulatory signaling domain. PSCA-CARs exhibit robust in vivo anti-tumor activity in patient-derived bone-metastatic prostate cancer xenograft models, and 4-1BB-containing CARs show superior T cell persistence and control of disease compared with CD28-containing CARs. Our study demonstrates the importance of co-stimulation in defining an optimal CAR T cell, and also highlights the significance of clinically relevant models in developing solid cancer CAR T cell therapies. PMID:29308300

Antigen storage compartments in mature dendritic cells facilitate prolonged cytotoxic T lymphocyte cross-priming capacity.

Science.gov (United States)

van Montfoort, Nadine; Camps, Marcel G; Khan, Selina; Filippov, Dmitri V; Weterings, Jimmy J; Griffith, Janice M; Geuze, Hans J; van Hall, Thorbald; Verbeek, J Sjef; Melief, Cornelis J; Ossendorp, Ferry

2009-04-21

Dendritic cells (DCs) are crucial for priming of naive CD8(+) T lymphocytes to exogenous antigens, so-called "cross-priming." We report that exogenous protein antigen can be conserved for several days in mature DCs, coinciding with strong cytotoxic T lymphocyte cross-priming potency in vivo. After MHC class I peptide elution, protein antigen-derived peptide presentation is efficiently restored, indicating the presence of an intracellular antigen depot. We characterized this depot as a lysosome-like organelle, distinct from MHC class II compartments and recently described early endosomal compartments that allow acute antigen presentation in MHC class I. The storage compartments we report here facilitate continuous supply of MHC class I ligands. This mechanism ensures sustained cross-presentation by DCs, despite the short-lived expression of MHC class I-peptide complexes at the cell surface.

Targeting Antigens to Dec-205 on Dendritic Cells Induces Immune Protection in Experimental Colitis in Mice

Science.gov (United States)

Wadwa, Munisch; Klopfleisch, Robert; Buer, Jan; Westendorf, Astrid M.

2016-01-01

The endocytotic c-type lectin receptor DEC-205 is highly expressed on immature dendritic cells. In previous studies, it was shown that antigen-targeting to DEC-205 is a useful tool for the induction of antigen-specific Foxp3+ regulatory T cells and thereby can prevent inflammatory processes. However, whether this approach is sufficient to mediate tolerance in mucosal tissues like the gut is unknown. In this study, we established a new mouse model in which the adoptive transfer of naive hemagglutinin (HA)-specific CD4+Foxp3– T cells into VILLIN-HA transgenic mice leads to severe colitis. To analyze if antigen-targeting to DEC-205 could protect against inflammation of the gut, VILLIN-HA transgenic mice were injected with an antibody–antigen complex consisting of the immunogenic HA110–120 peptide coupled to an α-DEC-205 antibody (DEC-HA) before adoptive T cell transfer. DEC-HA-treated mice showed significantly less signs of intestinal inflammation as was demonstrated by reduced loss of body weight and histopathology in the gut. Strikingly, abrogated intestinal inflammation was mediated via the conversion of naive HA-specific CD4+Foxp3– T cells into HA-specific CD4+Foxp3+ regulatory T cells. In this study, we provide evidence that antigen-targeting to DEC-205 can be utilized for the induction of tolerance in mucosal organs that are confronted with large numbers of exogenous antigens. PMID:27141310

FcepsilonRI-alpha siRNA inhibits the antigen-induced activation of mast cells.

Science.gov (United States)

Safaralizadeh, Reza; Soheili, Zahra-Soheila; Deezagi, Abdolkhaleg; Pourpak, Zahra; Samiei, Shahram; Moin, Mostafa

2009-12-01

FcepsilonRI, The high affinity receptor for IgE plays a critical role in triggering the allergic reactions. It is responsible for inducing mast cell degranulation and deliberation of allergy mediators when it is aggregated by allergen and IgE complexes. FcepsilonRI on the mast cells consists of three subunits; alpha chain directly binds IgE, beta chain and dimmer of gamma chains together mediate intracellular signaling. Cross-linking of IgE-bound FcepsilonRI on the surface of mast cells and basophils by the multivalent antigen induces release of chemical mediators. The present in vitro study was designed to investigate the effect of synthetic FcepsilonRI-alpha siRNA on the antigen-induced activation of MC/9 cells. MC/9 cells which are murine mast cells were transfected by FcepsilonRI-alpha siRNA and negative control siRNA. After 6 h, anti-DNP (Dinitrophenyl) IgE was used for the cells sensitization. Then the cells were challenged with Dinitrophenyl-Human Serum Albumin (DNP-HSA) for mast cell degranulation induction before collection of supernatants. The amount of mRNA and protein expression was measured by Real Time PCR and western blot analysis, respectively. Determination of the expression rate of FcepsilonRI-alpha on cell surface was achieved by flow cytometry. ELISA and spectrophotometry methods were used subsequently for measuring the effects of FcepsilonRI-alpha siRNA on antigen-induced histamine and beta-hexosaminidase release. FcepsilonRI-alpha siRNA treated cells showed significant decrease in FcepsilonRI-alpha mRNA and protein expression in comparison to control cells. FcepsilonRI-mediated mast cell release of beta-hexosaminidase and histamine were also inhibited. In this study it was shown that FcepsilonRI-alpha siRNA could suppress FcepsilonRI-alpha expression and inhibited degranulation and histamine release in antigen-stimulated MC/9 cells. In conclusion, knock-down of FcepsilonRI-alpha by siRNA could be a promising method for inhibition of the mast

CD4+ T cell-mediated rejection of MHC class II-positive tumor cells is dependent on antigen secretion and indirect presentation on host APCs.

Science.gov (United States)

Haabeth, Ole Audun Werner; Fauskanger, Marte; Manzke, Melanie; Lundin, Katrin U; Corthay, Alexandre; Bogen, Bjarne; Tveita, Anders Aune

2018-05-11

Tumor-specific CD4+ T cells have been shown to mediate efficient anti-tumor immune responses against cancer. Such responses can occur through direct binding to MHC class II (MHC II)-expressing tumor cells or indirectly via activation of professional antigen-presenting cells (APC) that take up and present the tumor antigen. We have previously shown that CD4+ T cells reactive against an epitope within the Ig light chain variable region of a murine B cell lymphoma can reject established tumors. Given the presence of MHC II molecules at the surface of lymphoma cells, we investigated whether MHC II-restricted antigen presentation on tumor cells alone was required for rejection. Variants of the A20 B lymphoma cell line that either secreted or intracellularly retained different versions of the tumor-specific antigen revealed that antigen secretion by the MHC II-expressing tumor cells was essential both for the priming and effector phase of CD4+ T cell-driven anti-tumor immune responses. Consistent with this, genetic ablation of MHC II in tumor cells, both in the case of B lymphoma and B16 melanoma, did not preclude rejection of tumors by tumor antigen-specific CD4+ T cells in vivo. These findings demonstrate that MHC class II expression on tumor cells themselves is not required for CD4+ T cell-mediated rejection, and that indirect display on host APC is sufficient for effective tumor elimination. These results support the importance of tumor-infiltrating APC as mediators of tumor cell killing by CD4+ T cells. Copyright ©2018, American Association for Cancer Research.

Robust and Accurate Discrimination of Self/Non-Self Antigen Presentations by Regulatory T Cell Suppression

OpenAIRE

Furusawa, Chikara; Yamaguchi, Tomoyuki

2016-01-01

The immune response by T cells usually discriminates self and non-self antigens, even though the negative selection of self-reactive T cells is imperfect and a certain fraction of T cells can respond to self-antigens. In this study, we construct a simple mathematical model of T cell populations to analyze how such self/non-self discrimination is possible. The results demonstrate that the control of the immune response by regulatory T cells enables a robust and accurate discrimination of self ...

Bone marrow-derived thymic antigen-presenting cells determine self-recognition of Ia-restricted T lymphocytes

International Nuclear Information System (INIS)

Longo, D.L.; Kruisbeek, A.M.; Davis, M.L.; Matis, L.A.

1985-01-01

The authors previously have demonstrated that in radiation-induced bone marrow chimeras, T-cell self-Ia restriction specificity appeared to correlate with the phenotype of the bone marrow-derived antigen-presenting (or dendritic) cell in the thymus during T-cell development. However, these correlations were necessarily indirect because of the difficulty in assaying thymic function directly by adult thymus transplant, which has in the past been uniformly unsuccessful. They now report success in obtaining functional T cells from nude mice grafted with adult thymuses reduced in size by treatment of the thymus donor with anti-thymocyte globulin and cortisone. When (B10 Scn X B10.D2)F1 nude mice (I-Ab,d) are given parental B10.D2 (I-Ad) thymus grafts subcutaneously, their T cells are restricted to antigen recognition in association with I-Ad gene products but not I-Ab gene products. Furthermore, thymuses from (B10 X B10.D2)F1 (I-Ab,d)----B10 (I-Ab) chimeras transplanted 6 months or longer after radiation (a time at which antigen-presenting cell function is of donor bone marrow phenotype) into (B10 X B10.D2)F1 nude mice generate T cells restricted to antigen recognition in association with both I-Ad and I-Ab gene products. Thymuses from totally allogeneic bone marrow chimeras appear to generate T cells of bone marrow donor and thymic host restriction specificity. Thus, when thymus donors are radiation-induced bone marrow chimeras, the T-cell I-region restriction of the nude mice recipients is determined at least in part by the phenotype of the bone marrow-derived thymic antigen presenting cells or dendritic cells in the chimeric thymus

Antigen-presenting cells transfected with Hsp65 messenger RNA fail to treat experimental tuberculosis

Energy Technology Data Exchange (ETDEWEB)

Rocha, C.D.; Trombone, A.P.F.; Lorenzi, J.C.C.; Almeida, L.P.; Gembre, A.F.; Padilha, E. [Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Ramos, S.G. [Departamento de Patologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Silva, C.L.; Coelho-Castelo, A.A.M. [Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

2012-09-21

In the last several years, the use of dendritic cells has been studied as a therapeutic strategy against tumors. Dendritic cells can be pulsed with peptides or full-length protein, or they can be transfected with DNA or RNA. However, comparative studies suggest that transfecting dendritic cells with messenger RNA (mRNA) is superior to other antigen-loading techniques in generating immunocompetent dendritic cells. In the present study, we evaluated a new therapeutic strategy to fight tuberculosis using dendritic cells and macrophages transfected with Hsp65 mRNA. First, we demonstrated that antigen-presenting cells transfected with Hsp65 mRNA exhibit a higher level of expression of co-stimulatory molecules, suggesting that Hsp65 mRNA has immunostimulatory properties. We also demonstrated that spleen cells obtained from animals immunized with mock and Hsp65 mRNA-transfected dendritic cells were able to generate a mixed Th1/Th2 response with production not only of IFN-γ but also of IL-5 and IL-10. In contrast, cells recovered from mice immunized with Hsp65 mRNA-transfected macrophages were able to produce only IL-5. When mice were infected with Mycobacterium tuberculosis and treated with antigen-presenting cells transfected with Hsp65 mRNA (therapeutic immunization), we did not detect any decrease in the lung bacterial load or any preservation of the lung parenchyma, indicating the inability of transfected cells to confer curative effects against tuberculosis. In spite of the lack of therapeutic efficacy, this study reports for the first time the use of antigen-presenting cells transfected with mRNA in experimental tuberculosis.

Phenotype of Antigen Unexperienced TH Cells in the Inflamed Central Nervous System in Experimental Autoimmune Encephalomyelitis.

Science.gov (United States)

Franck, Sophia; Paterka, Magdalena; Birkenstock, Jerome; Zipp, Frauke; Siffrin, Volker; Witsch, Esther

2017-06-01

Multiple sclerosis is a chronic, disseminated inflammation of the central nervous system which is thought to be driven by autoimmune T cells. Genetic association studies in multiple sclerosis and a large number of studies in the animal model of the disease support a role for effector/memory T helper cells. However, the mechanisms underlying relapses, remission and chronic progression in multiple sclerosis or the animal model experimental autoimmune encephalomyelitis, are not clear. In particular, there is only scarce information on the role of central nervous system-invading naive T helper cells in these processes. By applying two-photon laser scanning microscopy we could show in vivo that antigen unexperienced T helper cells migrated into the deep parenchyma of the inflamed central nervous system in experimental autoimmune encephalomyelitis, independent of their antigen specificity. Using flow cytometric analyses of central nervous system-derived lymphocytes we found that only antigen-specific, formerly naive T helper cells became activated during inflammation of the central nervous system encountering their corresponding antigen.

Molecular signatures distinguishing active from latent tuberculosis in peripheral blood mononuclear cells, after in vitro antigenic stimulation with purified protein derivative of tuberculin (PPD) or Candida: a preliminary report.

Science.gov (United States)

Stern, Joel N H; Keskin, Derin B; Romero, Viviana; Zuniga, Joaquin; Encinales, Liliana; Li, Changlin; Awad, Carlos; Yunis, Edmond J

2009-01-01

Purified protein derivative (PPD) or tuberculin skin testing is used to identify infected individuals with Mycobacterium tuberculosis (Mtb) and to assess cell-mediated immunity to Mtb. In the present study, we compared PBMC cultures in the presence of tuberculin or Candida antigens using cytokine bead arrays and RNA microarrays. Measurements of different cytokines and chemokines in supernatants of PMBC cultures in the presence of PPD showed increased levels of interferon (IFN)-gamma in active tuberculosis infection (ATBI) and latent TB infected (LTBI) compared to controls, and increased levels of TNF-alpha in ATBI compared with LTBI. Also, we found increase of IL-6 in cultures of PPD positive and controls but not in the cultures with Candida. We also report the molecular signature of tuberculosis infection, in ATBI patients, the following genes were found to be up-regulated and absent in LTBI individuals: two kinases (JAK3 and p38MAPK), four interleukins (IL-7, IL-2, IL-6, and IFNbeta1), a chemokine (HCC-4) a chemokine receptor (CxCR5), two interleukin receptors (IL-1R2 and IL-18R1), and three additional ones (TRAF5, Smad2, CIITA, and NOS2A). By contrast, IL-17 and IGFBP3 were significantly up-regulated in LTBI. And, STAT4, GATA3, Fra-1, and ICOS were down-regulated in ATBI but absent in LTBI. Conversely, TLR-10, IL-15, DORA, and IKK-beta were down-regulated in LTBI but not in ATBI. Interestingly, the majority of the up-regulated genes found in ATBI were found in cultures stimulated with tuberculin (PPD) or Candida antigens, suggesting that these pathogens stimulate similar immunological pathways. We believe that the molecular signature distinguishing active from latent tuberculosis infection may require using cytokine bead arrays along with RNA microarrays testing cell cultures at different times following in vitro proliferation assays using several bacterial antigens and PPD.

Crystallization and X-ray diffraction studies of crustacean proliferating cell nuclear antigen

International Nuclear Information System (INIS)

Carrasco-Miranda, Jesus S.; Cardona-Felix, Cesar S.; Lopez-Zavala, Alonso A.; Re Vega, Enrique de la; De la Mora, Eugenio; Rudiño-Piñera, Enrique; Sotelo-Mundo, Rogerio R.; Brieba, Luis G.

2012-01-01

Proliferating cell nuclear antigen from Litopenaeus vannamei was recombinantly expressed, purified and crystallized. Diffraction data were obtained and processed to 3 Å. Proliferating cell nuclear antigen (PCNA), a member of the sliding clamp family of proteins, interacts specifically with DNA replication and repair proteins through a small peptide motif called the PCNA-interacting protein or PIP box. PCNA is recognized as one of the key proteins involved in DNA metabolism. In the present study, the recombinant PCNA from Litopenaeus vannamei (LvPCNA) was heterologously overexpressed and purified using metal ion-affinity chromatography. Crystals suitable for diffraction grew overnight using the hanging-drop vapour-diffusion method. LvPCNA crystals belong to space group C2 with unit-cell parameters a = 144.6, b = 83.4, c = 74.3 Å, β = 117.6°. One data set was processed to 3 Å resolution, with an overall R meas of 0.09 and a completeness of 93.3%. Initial phases were obtained by molecular replacement using a homology model of LvPCNA as the search model. Refinement and structural analysis are underway. This report is the first successful crystallographic analysis of a marine crustacean decapod shrimp (L. vannamei) proliferating cell nuclear antigen

Sensitization of multidrug-resistant human cancer cells to Hsp90 inhibitors by down-regulation of SIRT1

Science.gov (United States)

Kim, Hak-Bong; Lee, Su-Hoon; Um, Jee-Hyun; Oh, Won Keun; Kim, Dong-Wan; Kang, Chi-Dug; Kim, Sun-Hee

2015-01-01

The effectiveness of Hsp90 inhibitors as anticancer agents was limited in multidrug-resistant (MDR) human cancer cells due to induction of heat shock proteins (Hsps) such as Hsp70/Hsp27 and P-glycoprotein (P-gp)-mediated efflux. In the present study, we showed that resistance to Hsp90 inhibitors of MDR human cancer cells could be overcome with SIRT1 inhibition. SIRT1 knock-down or SIRT1 inhibitors (amurensin G and EX527) effectively suppressed the resistance to Hsp90 inhibitors (17-AAG and AUY922) in several MDR variants of human lymphoblastic leukemia and human breast cancer cell lines. SIRT1 inhibition down-regulated the expression of heat shock factor 1 (HSF1) and subsequently Hsps and facilitated Hsp90 multichaperone complex disruption via hyperacetylation of Hsp90/Hsp70. These findings were followed by acceleration of ubiquitin ligase CHIP-mediated mutant p53 (mut p53) degradation and subsequent down-regulation of P-gp in 17-AAG-treated MDR cancer cells expressing P-gp and mut p53 after inhibition of SIRT1. Therefore, combined treatment with Hsp90 inhibitor and SIRT1 inhibitor could be a more effective therapeutic approach for Hsp90 inhibitor-resistant MDR cells via down-regulation of HSF1/Hsps, mut p53 and P-gp. PMID:26416354

Neonatal colonisation expands a specific intestinal antigen-presenting cell subset prior to CD4 T-cell expansion, without altering T-cell repertoire.

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Charlotte F Inman

Full Text Available Interactions between the early-life colonising intestinal microbiota and the developing immune system are critical in determining the nature of immune responses in later life. Studies in neonatal animals in which this interaction can be examined are central to understanding the mechanisms by which the microbiota impacts on immune development and to developing therapies based on manipulation of the microbiome. The inbred piglet model represents a system that is comparable to human neonates and allows for control of the impact of maternal factors. Here we show that colonisation with a defined microbiota produces expansion of mucosal plasma cells and of T-lymphocytes without altering the repertoire of alpha beta T-cells in the intestine. Importantly, this is preceded by microbially-induced expansion of a signal regulatory protein α-positive (SIRPα(+ antigen-presenting cell subset, whilst SIRPα(-CD11R1(+ antigen-presenting cells (APCs are unaffected by colonisation. The central role of intestinal APCs in the induction and maintenance of mucosal immunity implicates SIRPα(+ antigen-presenting cells as orchestrators of early-life mucosal immune development.

Relative Efficacy of Uptake and Presentation of Mycobacterium bovis BCG Antigens by Type I Mouse Lung Epithelial Cells and Peritoneal Macrophages ▿

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Kumari, Mandavi; Saxena, Rajiv K.

2011-01-01

Flow cytometric studies indicated that both peritoneal macrophages (PMs) and primary lung epithelial (PLE) cells isolated from mouse lungs could take up fluorescence-tagged Mycobacterium bovis BCG. BCG uptake in both cases was significantly inhibited by cytochalasin D, indicating active internalization of BCG by these cells. Confocal microscopy data further confirmed that BCG was internalized by PLE cells. BCG sonicate antigen (sBCG) had marked toxicity toward PMs but was relatively nontoxic to PLE cells. Accordingly, BCG sonicate antigen induced a significantly higher apoptotic and necrotic response in PMs compared to that in PLE cells. Both PMs and PLE cells exposed to BCG antigens and fixed thereafter could efficiently present antigens to purified BCG-sensitized T helper cells, as assessed by the release of interleukin-2 (IL-2) and gamma interferon (IFN-γ). If, however, PLE cells were fixed before exposure to BCG, antigen presentation was abrogated, indicating that the PLE cells may in some way process the BCG antigen. A comparison of efficacies of BCG-pulsed PLE cells and PMs to present antigen at various antigen-presenting cell (APC)/T cell ratios indicated that PMs had only marginally greater APC function than that of PLE cells. Staining with specific monoclonal antibodies indicated that the cultured PLE cells used for antigen presentation essentially comprised type I epithelial cells. Our results suggest that type I lung epithelial cells may present BCG antigens to sensitized T helper cells and that their performance as APCs is comparable with that of PMs. PMID:21646448

B cell antigen receptor signaling and internalization are mutually exclusive events.

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Ping Hou

2006-07-01

Full Text Available Engagement of the B cell antigen receptor initiates two concurrent processes, signaling and receptor internalization. While both are required for normal humoral immune responses, the relationship between these two processes is unknown. Herein, we demonstrate that following receptor ligation, a small subpopulation of B cell antigen receptors are inductively phosphorylated and selectively retained at the cell surface where they can serve as scaffolds for the assembly of signaling molecules. In contrast, the larger population of non-phosphorylated receptors is rapidly endocytosed. Each receptor can undergo only one of two mutually exclusive fates because the tyrosine-based motifs that mediate signaling when phosphorylated mediate internalization when not phosphorylated. Mathematical modeling indicates that the observed competition between receptor phosphorylation and internalization enhances signaling responses to low avidity ligands.

In vitro stimulation of rabbit T lymphocytes by cells expressing herpes simplex antigens.

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Kapoor, A K; Ling, N R; Nash, A A; Bachan, A; Wildy, P

1982-04-01

Lymphocyte stimulation responses to herpes antigens were studied using virus-infected X-irradiated cells. Rabbits were immunized with herpes simplex virus type 1 (strain HFEM) grown in RK 13 cells. For in vitro stimulation assay BHK21 cells were X-irradiated (15 000 rad) and infected with a high m.o.i. of a temperature-sensitive (ts) mutant (N102) of HFEM strain at the non-permissive temperature (38.5 degrees C) of virus. Virus antigens were expressed on the infected cells and there was no leakage of infectious virus into the medium at 38.5 degrees C. T lymphocytes from rabbits immunized with herpes simplex virus were specifically activated by herpesvirus-infected X-irradiated cells; lymph node cells from rabbits immunized with RK13 cells and from non-immune rabbits showed no proliferative response.

Estradiol-induced vaginal mucus inhibits antigen penetration and CD8(+) T cell priming in response to intravaginal immunization.

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Seavey, Matthew M; Mosmann, Tim R

2009-04-14

Although vaginal immunization has been explored as a strategy to induce mucosal immunity in the female reproductive tract, this site displays unique immunological features that probably evolved to inhibit anti-paternal T cell responses after insemination to allow successful pregnancy. We previously demonstrated that estradiol, which induces an estrus-like state, prevented CD8(+) T cell priming during intravaginal immunization of mice. We now show that estradiol prevented antigen loading of vaginal antigen presenting cells (APCs) after intravaginal immunization. Histological examination confirmed that estradiol prevented penetration of peptide antigen into the vaginal wall. Removal of the estradiol-induced mucus barrier by mucinase partially restored antigen loading of vaginal APC and CD8(+) T cell proliferation in vivo. The estradiol-induced mucus barrier may thus prevent exposure to antigens delivered intravaginally, supplementing additional estradiol-dependent mechanism(s) that inhibit CD8(+) T cell priming after insemination or vaginal vaccination.

Estradiol-induced vaginal mucus inhibits antigen penetration and CD8+ T cell priming in response to intravaginal immunization

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Seavey, Matthew M.; Mosmann, Tim R.

2010-01-01

Although vaginal immunization has been explored as a strategy to induce mucosal immunity in the female reproductive tract, this site displays unique immunological features that probably evolved to inhibit anti-paternal T cell responses after insemination to allow successful pregnancy. We previously demonstrated that estradiol, which induces an estrus-like state, prevented CD8+ T cell priming during intravaginal immunization of mice. We now show that estradiol prevented antigen loading of vaginal antigen presenting cells (APC) after intravaginal immunization. Histological examination confirmed that estradiol prevented penetration of peptide antigen into the vaginal wall. Removal of the estradiol-induced mucus barrier by mucinase partially restored antigen loading of vaginal APC and CD8+ T cell proliferation in vivo. The estradiol-induced mucus barrier may thus prevent exposure to antigens delivered intravaginally, supplementing additional estradiol-dependent mechanism(s) that inhibit CD8+ T cell priming after insemination or vaginal vaccination. PMID:19428849

Endothelial cells present antigens in vivo

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Tellides George

2004-03-01

Full Text Available Abstract Background Immune recognition of vascular endothelial cells (EC has been implicated in allograft rejection, protection against pathogens, and lymphocyte recruitment. However, EC pervade nearly all tissues and predominate in none, complicating any direct test of immune recognition. Here, we examined antigen presentation by EC in vivo by testing immune responses against E. coli β-galactosidase (β-gal in two lines of transgenic mice that express β-gal exclusively in their EC. TIE2-lacZ mice express β-gal in all EC and VWF-lacZ mice express β-gal in heart and brain microvascular EC. Results Transgenic and congenic wild type FVB mice immunized with β-gal expression vector DNA or β-gal protein generated high titer, high affinity antisera containing comparable levels of antigen-specific IgG1 and IgG2a isotypes, suggesting equivalent activation of T helper cell subsets. The immunized transgenic mice remained healthy, their EC continued to express β-gal, and their blood vessels showed no histological abnormalities. In response to β-gal in vitro, CD4+ and CD8+ T cells from immunized transgenic and FVB mice proliferated, expressed CD25, and secreted IFN-γ. Infection with recombinant vaccinia virus encoding β-gal raised equivalent responses in transgenic and FVB mice. Hearts transplanted from transgenic mice into FVB mice continued to beat and the graft EC continued to express β-gal. These results suggested immunological ignorance of the transgene encoded EC protein. However, skin transplanted from TIE2-lacZ onto FVB mice lost β-gal+ EC and the hosts developed β-gal-specific antisera, demonstrating activation of host immune effector mechanisms. In contrast, skin grafted from TIE2-lacZ onto VWF-lacZ mice retained β-gal+ EC and no antisera developed, suggesting a tolerant host immune system. Conclusion Resting, β-gal+ EC in transgenic mice tolerize specific lymphocytes that would otherwise respond against β-gal expressed by EC within

Identification of the soluble HVP-associated antigen of the lymphoblastoid cell line established from lymphomatous baboon (Papio hamadryas).

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Voevodin, A F; Lapin, B A; Agrba, V Z; Timanovskaya, V V

1978-01-01

A new technique (indirect double immunodiffusion) for detection of EBV-associated soluble antigen and corresponding antibodies has been developed. This technique includes three steps: 1) simple double immunodiffusion with extracts of Raji cells (or other EBV-genome positive cells) and human sera containing antibodies against EBV-associated soluble antigen; 2) extensive washing and treatment with anti-human globulin; 3) extensive washing and treatment with tannic acid. Using this test it was shown that the soluble antigen indistinguishable from EBV-associated soluble antigen was present in KMPG-1 cells producing HVP.

Evaluation of accessory cell heterogeneity. III. Role of dendritic cells in the in vitro activation of the antibody response to soluble antigens.

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Erb, P; Ramila, G; Sklenar, I; Kennedy, M; Sunshine, G H

1985-05-01

Dendritic cells and macrophages obtained from spleen and peritoneal exudate were tested as accessory cells for the activation of lymphokine production by T cells, for supporting T-B cooperation and for the induction of antigen-specific T helper cells. Dendritic cells as well as macrophages were able to activate T cells for interleukin-2 secretion and functioned as accessory cells in T-B cooperation, but only macrophages induced T helper cells, which cooperate with B cells by a linked recognition interaction, to soluble antigens. Dendritic cell- and antigen-activated T cells also did not help B cells in the presence of Con A supernatants which contained various T cell- and B cell-stimulatory factors. The failure of dendritic cells to differentiate memory into functional T helper cells, but their efficient accessory cell function in T-B cooperation, where functional T helper cells are already present, can be best explained by a differential accessory cell requirement for T helper cell activation dependent on the differentiation stage of the T helper cell.

Use of immunoradiometric analysis to determine Rickettsia antigens in cell cultures and chick embryos

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Prozorovskiy, S.V.; Alekseeva, N.V.; Knyazeva, E.N.; Ignatovich, V.F.; Barkhatova, O.T.

1984-02-01

A modification of an immunoradiometric analysis to determine Rickettsia antigens in various biological substrates was studied, using rickettsious diagnostricums, egg and cell cultures of Rickettsia. The method was highly sensitive for the determination of minimal quantities of antigens in these substrates. The method appears to be promising for studies related to the detection of microorganisms and their antigens. 5 references.

Downregulation of NEDD9 by apigenin suppresses migration, invasion, and metastasis of colorectal cancer cells

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Dai, Jin; Van Wie, Peter G.; Fai, Leonard Yenwong; Kim, Donghern; Wang, Lei; Poyil, Pratheeshkumar; Luo, Jia; Zhang, Zhuo

2016-01-01

Apigenin is a natural flavonoid which possesses multiple anti-cancer properties such as anti-proliferation, anti-inflammation, and anti-metastasis in many types of cancers including colorectal cancer. Neural precursor cell expressed developmentally downregulated 9 (NEDD9) is a multi-domain scaffolding protein of the Cas family which has been shown to correlate with cancer metastasis and progression. The present study investigates the role of NEDD9 in apigenin-inhibited cell migration, invasion, and metastasis of colorectal adenocarcinoma DLD1 and SW480 cells. The results show that knockdown of NEDD9 inhibited cell migration, invasion, and metastasis and that overexpression of NEDD9 promoted cell migration and invasion of DLD1 cells and SW4890 cells. Apigenin treatment attenuated NEDD9 expression at protein level, resulting in reduced phosphorylations of FAK, Src, and Akt, leading to inhibition on cell migration, invasion, and metastasis of both DLD1 and SW480 cells. The present study has demonstrated that apigenin inhibits cell migration, invasion, and metastasis through NEDD9/Src/Akt cascade in colorectal cancer cells. NEDD9 may function as a biomarker for evaluation of cancer aggressiveness and for selection of therapeutic drugs against cancer progression. - Highlights: • Apigenin inhibits migration, invasion, and metastasis of colorectal cancer cells. • Apigenin downregulates NEDD9. • Apigenin decreases phosphorylations of FAK, Src, and Akt. • Apigenin inhibits cell migration, invasion, and metastasis through NEDD9/Src/Akt.

Downregulation of NEDD9 by apigenin suppresses migration, invasion, and metastasis of colorectal cancer cells

Energy Technology Data Exchange (ETDEWEB)

Dai, Jin; Van Wie, Peter G.; Fai, Leonard Yenwong; Kim, Donghern [Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40536 (United States); Wang, Lei; Poyil, Pratheeshkumar [Center for Research on Environmental Disease, University of Kentucky, Lexington, KY 40536 (United States); Luo, Jia [Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY 40536 (United States); Zhang, Zhuo, E-mail: Zhuo.Zhang@uky.edu [Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40536 (United States)

2016-11-15

Apigenin is a natural flavonoid which possesses multiple anti-cancer properties such as anti-proliferation, anti-inflammation, and anti-metastasis in many types of cancers including colorectal cancer. Neural precursor cell expressed developmentally downregulated 9 (NEDD9) is a multi-domain scaffolding protein of the Cas family which has been shown to correlate with cancer metastasis and progression. The present study investigates the role of NEDD9 in apigenin-inhibited cell migration, invasion, and metastasis of colorectal adenocarcinoma DLD1 and SW480 cells. The results show that knockdown of NEDD9 inhibited cell migration, invasion, and metastasis and that overexpression of NEDD9 promoted cell migration and invasion of DLD1 cells and SW4890 cells. Apigenin treatment attenuated NEDD9 expression at protein level, resulting in reduced phosphorylations of FAK, Src, and Akt, leading to inhibition on cell migration, invasion, and metastasis of both DLD1 and SW480 cells. The present study has demonstrated that apigenin inhibits cell migration, invasion, and metastasis through NEDD9/Src/Akt cascade in colorectal cancer cells. NEDD9 may function as a biomarker for evaluation of cancer aggressiveness and for selection of therapeutic drugs against cancer progression. - Highlights: • Apigenin inhibits migration, invasion, and metastasis of colorectal cancer cells. • Apigenin downregulates NEDD9. • Apigenin decreases phosphorylations of FAK, Src, and Akt. • Apigenin inhibits cell migration, invasion, and metastasis through NEDD9/Src/Akt.

Adoptive Immunotherapy for Hematological Malignancies Using T Cells Gene-Modified to Express Tumor Antigen-Specific Receptors

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