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Sample records for bystander cells restricts

  1. Fiber mediated receptor masking in non-infected bystander cells restricts adenovirus cell killing effect but promotes adenovirus host co-existence.

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    Johan Rebetz

    Full Text Available The basic concept of conditionally replicating adenoviruses (CRAD as oncolytic agents is that progenies generated from each round of infection will disperse, infect and kill new cancer cells. However, CRAD has only inhibited, but not eradicated tumor growth in xenograft tumor therapy, and CRAD therapy has had only marginal clinical benefit to cancer patients. Here, we found that CRAD propagation and cancer cell survival co-existed for long periods of time when infection was initiated at low multiplicity of infection (MOI, and cancer cell killing was inefficient and slow compared to the assumed cell killing effect upon infection at high MOI. Excessive production of fiber molecules from initial CRAD infection of only 1 to 2% cancer cells and their release prior to the viral particle itself caused a tropism-specific receptor masking in both infected and non-infected bystander cells. Consequently, the non-infected bystander cells were inefficiently bound and infected by CRAD progenies. Further, fiber overproduction with concomitant restriction of adenovirus spread was observed in xenograft cancer therapy models. Besides the CAR-binding Ad4, Ad5, and Ad37, infection with CD46-binding Ad35 and Ad11 also caused receptor masking. Fiber overproduction and its resulting receptor masking thus play a key role in limiting CRAD functionality, but potentially promote adenovirus and host cell co-existence. These findings also give important clues for understanding mechanisms underlying the natural infection course of various adenoviruses.

  2. Bystander T cells in human immune responses to dengue antigens

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    Suwannasaen Duangchan

    2010-09-01

    Full Text Available Abstract Background Previous studies of T cell activation in dengue infection have focused on restriction of specific T cell receptors (TCRs and classical MHC molecules. However, bystander T cell activation, which is TCR independent, occurs via cytokines in other viral infections, both in vitro and in vivo, and enables T cells to bypass certain control checkpoints. Moreover, clinical and pathological evidence has pointed to cytokines as the mediators of dengue disease severity. Therefore, we investigated bystander T cell induction by dengue viral antigen. Results Whole blood samples from 55 Thai schoolchildren aged 13-14 years were assayed for in vitro interferon-gamma (IFN-γ induction in response to inactivated dengue serotype 2 antigen (Den2. The contribution of TCR-dependent and independent pathways was tested by treatment with cyclosporin A (CsA, which inhibits TCR-dependent activation of T cells. ELISA results revealed that approximately 72% of IFN-γ production occurred via the TCR-dependent pathway. The major IFN-γ sources were natural killer (NK (mean ± SE = 55.2 ± 3.3, CD4+T (24.5 ± 3.3 and CD8+T cells (17.9 ± 1.5, respectively, as demonstrated by four-color flow cytometry. Interestingly, in addition to these cells, we found CsA-resistant IFN-γ producing T cells (CD4+T = 26.9 ± 3.6% and CD8+T = 20.3 ± 2.1% implying the existence of activated bystander T cells in response to dengue antigen in vitro. These bystander CD4+ and CD8+T cells had similar kinetics to NK cells, appeared after 12 h and were inhibited by anti-IL-12 neutralization indicating cytokine involvement. Conclusions This study described immune cell profiles and highlighted bystander T cell activation in response to dengue viral antigens of healthy people in an endemic area. Further studies on bystander T cell activation in dengue viral infection may reveal the immune mechanisms that protect or enhance pathogenesis of secondary dengue infection.

  3. Radiation-induced bystander effects enhanced by elevated sodium chloride through sensitizing cells to bystander factors

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    Zhu Lingyan; Han Wei; Chen Shaopeng; Zhao Ye; Jiang Erkang; Bao Lingzhi; Pei Bei; Yang Gen; Zhao Guoping; Wang Jun; Xu An [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, Anhui (China); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, Anhui (China)], E-mail: ljw@ipp.ac.cn

    2008-09-26

    Radiation-induced bystander effects (RIBE) have been demonstrated to occur widely in various cell lines. However, very little data is available on the genotoxic effects of RIBE combined with other factor(s). We reported previously that with a low dose of {alpha}-particle irradiation, the fraction of {gamma}-H2AX foci-positive cells in non-irradiated bystander cells was significantly increased under elevated NaCl culture conditions. In this study, we further investigated the functional role of NaCl in the enhancement of RIBE using a specially designed co-culture system and micronucleus (MN) test. It was shown that the MN frequency was not increased significantly by elevated NaCl (9.0 g/L) alone or by medium exposure. However, with 1.0 cGy {alpha}-particle irradiation, the induced MN frequency increased significantly in both irradiated and non-irradiated bystander regions. Additional studies showed that elevated NaCl made the non-irradiated bystander cells more vulnerable to bystander factors. Furthermore, it was found that the induced MN frequency in cells both in irradiated and non-irradiated bystander regions was weakened when the hypertonic medium was changed to normotonic medium for 2 h before irradiation. Such observations were quite similar to the co-effect of NaCl and hydrogen peroxide (H{sub 2}O{sub 2}), indicating that elevated NaCl might sensitize non-irradiated cells to bystander factors-induced oxidative stress.

  4. Radioprotection of targeted and bystander cells by methylproamine

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    Burdak-Rothkamm, Susanne [Queen' s University Belfast, Centre for Cancer Research and Cell Biology, Belfast (United Kingdom); Oxford University Hospitals, Cellular Pathology, Oxford (United Kingdom); Smith, Andrea; Lobachevsky, Pavel; Martin, Roger [Peter MacCallum Cancer Centre, Molecular Radiation Biology Laboratory, Melbourne (Australia); University of Melbourne, The Sir Peter MacCallum Department of Oncology, Melbourne (Australia); Prise, Kevin M. [Queen' s University Belfast, Centre for Cancer Research and Cell Biology, Belfast (United Kingdom)

    2014-09-23

    Radioprotective agents are of interest for application in radiotherapy for cancer and in public health medicine in the context of accidental radiation exposure. Methylproamine is the lead compound of a class of radioprotectors which act as DNA binding anti-oxidants, enabling the repair of transient radiation-induced oxidative DNA lesions. This study tested methylproamine for the radioprotection of both directly targeted and bystander cells. T98G glioma cells were treated with 15 μM methylproamine and exposed to {sup 137}Cs γ-ray/X-ray irradiation and He{sup 2+} microbeam irradiation. Radioprotection of directly targeted cells and bystander cells was measured by clonogenic survival or γH2AX assay. Radioprotection of directly targeted T98G cells by methylproamine was observed for {sup 137}Cs γ-rays and X-rays but not for He{sup 2+} charged particle irradiation. The effect of methylproamine on the bystander cell population was tested for both X-ray irradiation and He{sup 2+} ion microbeam irradiation. The X-ray bystander experiments were carried out by medium transfer from irradiated to non-irradiated cultures and three experimental designs were tested. Radioprotection was only observed when recipient cells were pretreated with the drug prior to exposure to the conditioned medium. In microbeam bystander experiments targeted and nontargeted cells were co-cultured with continuous methylproamine treatment during irradiation and postradiation incubation; radioprotection of bystander cells was observed. Methylproamine protected targeted cells from DNA damage caused by γ-ray or X-ray radiation but not He{sup 2+} ion radiation. Protection of bystander cells was independent of the type of radiation which the donor population received. (orig.) [German] Radioprotektive Agenzien sind sowohl in der Strahlentherapie von Krebserkrankungen als auch im Strahlenschutz im Zusammenhang mit akzidenteller Exposition von Bedeutung. Methylproamine ist die Leitsubstanz einer Klasse von

  5. Role of ATM in bystander signaling between human monocytes and lung adenocarcinoma cells.

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    Ghosh, Somnath; Ghosh, Anu; Krishna, Malini

    2015-12-01

    The response of a cell or tissue to ionizing radiation is mediated by direct damage to cellular components and indirect damage mediated by radiolysis of water. Radiation affects both irradiated cells and the surrounding cells and tissues. The radiation-induced bystander effect is defined by the presence of biological effects in cells that were not themselves in the field of irradiation. To establish the contribution of the bystander effect in the survival of the neighboring cells, lung carcinoma A549 cells were exposed to gamma-irradiation, 2Gy. The medium from the irradiated cells was transferred to non-irradiated A549 cells. Irradiated A549 cells as well as non-irradiated A549 cells cultured in the presence of medium from irradiated cells showed decrease in survival and increase in γ-H2AX and p-ATM foci, indicating a bystander effect. Bystander signaling was also observed between different cell types. Phorbol-12-myristate-13-acetate (PMA)-stimulated and gamma-irradiated U937 (human monocyte) cells induced a bystander response in non-irradiated A549 (lung carcinoma) cells as shown by decreased survival and increased γ-H2AX and p-ATM foci. Non-stimulated and/or irradiated U937 cells did not induce such effects in non-irradiated A549 cells. Since ATM protein was activated in irradiated cells as well as bystander cells, it was of interest to understand its role in bystander effect. Suppression of ATM with siRNA in A549 cells completely inhibited bystander effect in bystander A549 cells. On the other hand suppression of ATM with siRNA in PMA stimulated U937 cells caused only a partial inhibition of bystander effect in bystander A549 cells. These results indicate that apart from ATM, some additional factor may be involved in bystander effect between different cell types.

  6. Rescue effects in radiobiology: Unirradiated bystander cells assist irradiated cells through intercellular signal feedback

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    Chen, S. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhao, Y. [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Han, W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Chiu, S.K. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Zhu, L. [Office of Admission and Careers Advisory Service, Shenzhen University, Shenzhen 518060 (China); Wu, L. [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, K.N., E-mail: peter.yu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2011-01-10

    Mammalian cells respond to ionization radiation by sending out extracellular signals to affect non-irradiated neighboring cells, which is referred to as radiation induced bystander effect. In the present paper, we described a phenomenon entitled the 'rescue effects', where the bystander cells rescued the irradiated cells through intercellular signal feedback. The effect was observed in both human primary fibroblast (NHLF) and cancer cells (HeLa) using two-cell co-culture systems. After co-culturing irradiated cells with unirradiated bystander cells for 24 h, the numbers of 53BP1 foci, corresponding to the number of DNA double-strand breaks in the irradiated cells were less than those in the irradiated cells that were not co-cultured with the bystander cells (0.78 {+-} 0.04 foci/cell vs. 0.90 {+-} 0.04 foci/cell) at a statistically significant level. Similarly, both micronucleus formation and extent of apoptosis in the irradiated cells were different at statistically significant levels if they were co-cultured with the bystander cells. Furthermore, it was found that unirradiated normal cells would also reduce the micronucleus formation in irradiated cancer cells. These results suggested that the rescue effects could participate in repairing the radiation-induced DNA damages through a media-mediated signaling feedback, thereby mitigating the cytotoxicity and genotoxicity of ionizing radiation.

  7. Proteome analysis of proliferative response of bystander cells adjacent to cells exposed to ionizing radiation.

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    Gerashchenko, Bogdan I; Yamagata, Akira; Oofusa, Ken; Yoshizato, Katsutoshi; de Toledo, Sonia M; Howell, Roger W

    2007-06-01

    Recently (Cytometry 2003, 56A, 71-80), we reported that direct cell-to-cell contact is required for stimulating proliferation of bystander rat liver cells (WB-F344) cocultured with irradiated cells, and neither functional gap junction intercellular communication nor long-range extracellular factors appear to be involved in this proliferative bystander response (PBR). The molecular basis for this response is unknown. Confluent monolayers of WB-F344 cells were exposed to 5-Gray (Gy) of gamma-rays. Irradiated cells were mixed with unirradiated cells and co-cultured for 24 h. Cells were harvested and protein expression was examined using 2-DE. Protein expression was also determined in cultures of unirradiated and 5-Gy irradiated cells. Proteins were identified by MS. Nucleophosmin (NPM)-1, a multifunctional nucleolar protein, was more highly expressed in bystander cells than in either unirradiated or 5-Gy irradiated cells. Enolase-alpha, a glycolytic enzyme, was present in acidic and basic variants in unirradiated cells. In bystander and 5-Gy irradiated cells, the basic variant was weakly expressed, whereas the acidic variant was overwhelmingly present. These data indicate that the presence of irradiated cells can affect NPM-1 and enolase-alpha in adjacent bystander cells. These proteins appear to participate in molecular events related to the PBR and suggest that this response may involve cellular defense, proliferation, and metabolism.

  8. Bystander deixis

    DEFF Research Database (Denmark)

    Rijkhoff, Jan

    1998-01-01

    Romani and several other languages across the globe. The second part is concerned with the contextual factors that must have a place in a discourse model that wants to be able to handle linguistic manifestations of bystander deixis. Due the fact that Romani has typically been used for in...... have borrowed extensively from the Romani lexicon. It will appear that bystander deixis is a universally attested phenomenon which is not restricted to situations in which speakers wish to communicate without being understood by others....

  9. Autophagy promotes radiation-induced senescence but inhibits bystander effects in human breast cancer cells.

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    Huang, Yao-Huei; Yang, Pei-Ming; Chuah, Qiu-Yu; Lee, Yi-Jang; Hsieh, Yi-Fen; Peng, Chih-Wen; Chiu, Shu-Jun

    2014-07-01

    Ionizing radiation induces cellular senescence to suppress cancer cell proliferation. However, it also induces deleterious bystander effects in the unirradiated neighboring cells through the release of senescence-associated secretory phenotypes (SASPs) that promote tumor progression. Although autophagy has been reported to promote senescence, its role is still unclear. We previously showed that radiation induces senescence in PTTG1-depleted cancer cells. In this study, we found that autophagy was required for the radiation-induced senescence in PTTG1-depleted breast cancer cells. Inhibition of autophagy caused the cells to switch from radiation-induced senescence to apoptosis. Senescent cancer cells exerted bystander effects by promoting the invasion and migration of unirradiated cells through the release of CSF2 and the subsequently activation of the JAK2-STAT3 and AKT pathways. However, the radiation-induced bystander effects were correlated with the inhibition of endogenous autophagy in bystander cells, which also resulted from the activation of the CSF2-JAK2 pathway. The induction of autophagy by rapamycin reduced the radiation-induced bystander effects. This study reveals, for the first time, the dual role of autophagy in radiation-induced senescence and bystander effects.

  10. Bystander Host Cell Killing Effects of Clostridium perfringens Enterotoxin

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    Archana Shrestha

    2016-12-01

    Full Text Available Clostridium perfringens enterotoxin (CPE binds to claudin receptors, e.g., claudin-4, and then forms a pore that triggers cell death. Pure cultures of host cells that do not express claudin receptors, e.g., fibroblasts, are unaffected by pathophysiologically relevant CPE concentrations in vitro. However, both CPE-insensitive and CPE-sensitive host cells are present in vivo. Therefore, this study tested whether CPE treatment might affect fibroblasts when cocultured with CPE-sensitive claudin-4 fibroblast transfectants or Caco-2 cells. Under these conditions, immunofluorescence microscopy detected increased death of fibroblasts. This cytotoxic effect involved release of a toxic factor from the dying CPE-sensitive cells, since it could be reproduced using culture supernatants from CPE-treated sensitive cells. Supernatants from CPE-treated sensitive cells, particularly Caco-2 cells, were found to contain high levels of membrane vesicles, often containing a CPE species. However, most cytotoxic activity remained in those supernatants even after membrane vesicle depletion, and CPE was not detected in fibroblasts treated with supernatants from CPE-treated sensitive cells. Instead, characterization studies suggest that a major cytotoxic factor present in supernatants from CPE-treated sensitive cells may be a 10- to 30-kDa host serine protease or require the action of that host serine protease. Induction of caspase-3-mediated apoptosis was found to be important for triggering release of the cytotoxic factor(s from CPE-treated sensitive host cells. Furthermore, the cytotoxic factor(s in these supernatants was shown to induce a caspase-3-mediated killing of fibroblasts. This bystander killing effect due to release of cytotoxic factors from CPE-treated sensitive cells could contribute to CPE-mediated disease.

  11. Target irradiation induced bystander effects between stem-like and non stem-like cancer cells

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    Liu, Yu [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Kobayashi, Alisa [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Maeda, Takeshi [Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Fu, Qibin [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Oikawa, Masakazu [Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Yang, Gen, E-mail: gen.yang@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Konishi, Teruaki, E-mail: tkonishi@nirs.go.jp [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Uchihori, Yukio [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); and others

    2015-03-15

    Highlights: • Existence of radiation induced bystander effects (RIBE) between cancer stem-like cells (CSCs) and non stem-like cancer cells (NSCCs) in human fibrosarcoma HT1080 cells. • Existence of significant difference in generation and response of bystander signals between CSCs and NSCCs. • CSCs are significantly less sensitive to NO scavenger than that of NSCCs in terms of DNA double strand breaks induced by RIBE. - Abstract: Tumors are heterogeneous in nature and consist of multiple cell types. Among them, cancer stem-like cells (CSCs) are suggested to be the principal cause of tumor metastasis, resistance and recurrence. Therefore, understanding the behavior of CSCs in direct and indirect irradiations is crucial for clinical radiotherapy. Here, the CSCs and their counterpart non stem-like cancer cells (NSCCs) in human HT1080 fibrosarcoma cell line were sorted and labeled, then the two cell subtypes were mixed together and chosen separately to be irradiated via a proton microbeam. The radiation-induced bystander effect (RIBE) between the CSCs and NSCCs was measured by imaging 53BP1 foci, a widely used indicator for DNA double strand break (DSB). CSCs were found to be less active than NSCCs in both the generation and the response of bystander signals. Moreover, the nitric oxide (NO) scavenger c-PTIO can effectively alleviate the bystander effect in bystander NSCCs but not in bystander CSCs, indicating a difference of the two cell subtypes in NO signal response. To our knowledge, this is the first report shedding light on the RIBE between CSCs and NSCCs, which might contribute to a further understanding of the out-of-field effect in cancer radiotherapy.

  12. An extracellular DNA mediated bystander effect produced from low dose irradiated endothelial cells

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    Ermakov, Aleksei V., E-mail: avePlato@mail.ru [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Konkova, Marina S.; Kostyuk, Svetlana V.; Smirnova, Tatiana D.; Malinovskaya, Elena M.; Efremova, Liudmila V.; Veiko, Natalya N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation)

    2011-07-01

    The human umbilical vein endothelial cells culture was exposed to X-ray radiation in a low dose of 10 cGy. The fragments of extracellular genomic DNA (ecDNA{sup R}) were isolated from the culture medium after the short-term incubation. A culture medium of unirradiated endothelial cells was then supplemented with ecDNA{sup R}, followed by analysing the cells along the series of parameters (bystander effect). The exposed cells and bystander endotheliocytes showed similar response to low doses: approximation of the 1q12 loci of chromosome 1 and their transposition into the cellular nucleus, change in shape of the endotheliocytic nucleus, activation of the nucleolus organizing regions (NORs), actin polymerization, and an elevated level of DNA double-stranded breaks. Following blockade of TLR9 receptors with oligonucleotide-inhibitor or chloroquine in the bystander cells these effects - except of activation of NORs - on exposure to ecDNA{sup R} disappeared, with no bystander response thus observed. The presence of the radiation-induced apoptosis in the bystander effect being studied suggests a possibility for radiation-modified ecDNA fragments (i.e., stress signaling factors) to be released into the culture medium, whereas inhibition of TLR9 suggests the binding these ligands to the recipient cells. A similar DNA-signaling pathway in the bystander effect we previously described for human lymphocytes. Integrity of data makes it possible to suppose that a similar signaling mechanism which we demonstrated for lymphocytes (humoral system) might also be mediated in a monolayer culture of cells (cellular tissue) after the development of the bystander effect in them and transfer of stress signaling factors (ecDNA{sup R}) through the culture medium.

  13. The different radiation response and radiation-induced bystander effects in colorectal carcinoma cells differing in p53 status

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    Widel, Maria, E-mail: maria.widel@polsl.pl [Biosystems Group, Institute of Automatic Control, Silesian University of Technology, 16 Akademicka Street, 44-100 Gliwice (Poland); Lalik, Anna; Krzywon, Aleksandra [Biosystems Group, Institute of Automatic Control, Silesian University of Technology, 16 Akademicka Street, 44-100 Gliwice (Poland); Poleszczuk, Jan [College of Inter-faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, 93 Zwirki i Wigury Street, 02-089 Warsaw (Poland); Department of Integrated Mathematical Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida (United States); Fujarewicz, Krzysztof; Rzeszowska-Wolny, Joanna [Biosystems Group, Institute of Automatic Control, Silesian University of Technology, 16 Akademicka Street, 44-100 Gliwice (Poland)

    2015-08-15

    Highlights: • We tested radiation response and bystander effect on HCT116p53+/+ and p53−/− cells. • The p53+/+ cells developed premature senescence in exposed and bystander neighbors. • Directly exposed and bystander p53−/− cells died profoundly through apoptosis. • Interleukins 6 and 8 were differently generated by both cell lines. • NFκB path was activated mainly in p53+/+ hit cells, in p53 −/− in bystanders only. - Abstract: Radiation-induced bystander effect, appearing as different biological changes in cells that are not directly exposed to ionizing radiation but are under the influence of molecular signals secreted by irradiated neighbors, have recently attracted considerable interest due to their possible implication for radiotherapy. However, various cells present diverse radiosensitivity and bystander responses that depend, inter alia, on genetic status including TP53, the gene controlling the cell cycle, DNA repair and apoptosis. Here we compared the ionizing radiation and bystander responses of human colorectal carcinoma HCT116 cells with wild type or knockout TP53 using a transwell co-culture system. The viability of exposed to X-rays (0–8 Gy) and bystander cells of both lines showed a roughly comparable decline with increasing dose. The frequency of micronuclei was also comparable at lower doses but at higher increased considerably, especially in bystander TP53-/- cells. Moreover, the TP53-/- cells showed a significantly elevated frequency of apoptosis, while TP53+/+ counterparts expressed high level of senescence. The cross-matched experiments where irradiated cells of one line were co-cultured with non-irradiated cells of opposite line show that both cell lines were also able to induce bystander effects in their counterparts, however different endpoints revealed with different strength. Potential mediators of bystander effects, IL-6 and IL-8, were also generated differently in both lines. The knockout cells secreted IL-6 at

  14. Neutron exposures in human cells: bystander effect and relative biological effectiveness.

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    Isheeta Seth

    Full Text Available Bystander effects have been observed repeatedly in mammalian cells following photon and alpha particle irradiation. However, few studies have been performed to investigate bystander effects arising from neutron irradiation. Here we asked whether neutrons also induce a bystander effect in two normal human lymphoblastoid cell lines. These cells were exposed to fast neutrons produced by targeting a near-monoenergetic 50.5 MeV proton beam at a Be target (17 MeV average neutron energy, and irradiated-cell conditioned media (ICCM was transferred to unirradiated cells. The cytokinesis-block micronucleus assay was used to quantify genetic damage in radiation-naïve cells exposed to ICCM from cultures that received 0 (control, 0.5, 1, 1.5, 2, 3 or 4 Gy neutrons. Cells grown in ICCM from irradiated cells showed no significant increase in the frequencies of micronuclei or nucleoplasmic bridges compared to cells grown in ICCM from sham irradiated cells for either cell line. However, the neutron beam has a photon dose-contamination of 5%, which may modulate a neutron-induced bystander effect. To determine whether these low doses of contaminating photons can induce a bystander effect, cells were irradiated with cobalt-60 at doses equivalent to the percent contamination for each neutron dose. No significant increase in the frequencies of micronuclei or bridges was observed at these doses of photons for either cell line when cultured in ICCM. As expected, high doses of photons induced a clear bystander effect in both cell lines for micronuclei and bridges (p<0.0001. These data indicate that neutrons do not induce a bystander effect in these cells. Finally, neutrons had a relative biological effectiveness of 2.0 ± 0.13 for micronuclei and 5.8 ± 2.9 for bridges compared to cobalt-60. These results may be relevant to radiation therapy with fast neutrons and for regulatory agencies setting standards for neutron radiation protection and safety.

  15. Bystander responses in low dose irradiated cells treated with plasma from gamma irradiated blood

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    Acheva, A; Georgieva, R; Rupova, I; Boteva, R [Laboratory Molecular Radiobiology and Epidemiology, National Centre of Radiobiology and Radiation Protection, 132 Kliment Ohridski blvd, Sofia 1756 (Bulgaria); Lyng, F [Radiation and Environmental Science Center, Dublin Institute of Technology, Kevin st, Dublin 8 (Ireland)], E-mail: anjin_a@mail.bg

    2008-02-01

    There are two specific low-dose radiation-induced responses that have been the focus of radiobiologists' interest in recent years. These are the bystander effect in non-irradiated cells and the adaptive response to a challenge dose after prior low dose irradiation. In the present study we have investigated if plasma from irradiated blood can act as a 'challenge dose' on low dose irradiated reporter epithelial cells (HaCaT cell line). The main aim was to evaluate the overall effect of low dose irradiation (0.05 Gy) of reporter cells and the influence of bystander factors in plasma from 0.5 Gy gamma irradiated blood on these cells. The effects were estimated by clonogenic survival of the reporter cells. We also investigated the involvement of reactive oxygen species (ROS) as potential factors involved in the bystander signaling. Calcium fluxes and mitochondrial membrane potential (MMP) depolarization were also examined as a marker for initiation of apoptosis in the reporter cells. The results show that there are large individual differences in the production of bystander effects and adaptive responses between different donors. These may be due to the specific composition of the donor plasma. The observed effects generally could be divided into two groups: adaptive responses and additive effects. ROS appeared to be involved in the responses of the low dose pretreated reporter cells. In all cases there was a significant decrease in MMP which may be an early event in the apoptotic process. Calcium signaling also appeared to be involved in triggering apoptosis in the low dose pretreated reporter cells. The heterogeneity of the bystander responses makes them difficult to be modulated for medical uses. Specific plasma characteristics that cause these large differences in the responses would need to be identified to make them useful for radiotherapy.

  16. Cell damage from radiation-induced bystander effects for different cell densities simulated by a mathematical model via cellular automata

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    Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein, E-mail: spm@cdtn.b, E-mail: amsantos@cdtn.b, E-mail: seg@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nunes, Maria Eugenia S., E-mail: mariaeugenia@iceb.ufop.b [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

    2011-07-01

    During recent years, there has been a shift from an approach focused entirely on DNA as the main target of ionizing radiation to a vision that considers complex signaling pathways in cells and among cells within tissues. Several newly recognized responses were classified as the so-called non-target responses in which the biological effects are not directly related to the amount of energy deposited in the DNA of cells that were traversed by radiation. In 1992 the bystander effect was described referring to a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. In this work, we have developed a mathematical model via cellular automata, to quantify cell death induced by the bystander effect. The model is based on experiments with irradiated cells conditioned medium which suggests that irradiated cells secrete molecules in the medium that are capable of damaging other cells. The computational model consists of two-dimensional cellular automata which is able to simulate the transmission of bystander signals via extrinsic route and via Gap junctions. The model has been validated by experimental results in the literature. The time evolution of the effect and the dose-response curves were obtained in good accordance to them. Simulations were conducted for different values of bystander and irradiated cell densities with constant dose. From this work, we have obtained a relationship between cell density and effect. (author)

  17. The crosstalk between α-irradiated Beas-2B cells and its bystander U937 cells through MAPK and NF-κB signaling pathways

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    Fu, Jiamei; Yuan, Dexiao; Xiao, Linlin; Tu, Wenzhi; Dong, Chen; Liu, Weili; Shao, Chunlin, E-mail: clshao@shmu.edu.cn

    2016-01-15

    Highlights: • α-irradiated Beas-2B cells induced bystander effects in macrophage U937 cells. • The neighboring macrophages enhanced the damage of α-irradiated Beas-2B cells. • MAPK and NF-κB pathways were activated in U937 cells after cell co-culture. • NF-κB and MAPK pathways participated in the bilateral bystander responses. - Abstract: Although accumulated evidence suggests that α-particle irradiation induced bystander effect may relevant to lung injury and cancer risk assessment, the exact mechanisms are not yet elucidated. In the present study, a cell co-culture system was used to investigate the interaction between α-particle irradiated human bronchial epithelial cells (Beas-2B) and its bystander macrophage U937 cells. It was found that the cell co-culture amplified the detrimental effects of α-irradiation including cell viability decrease and apoptosis promotion on both irradiated cells and bystander cells in a feedback loop which was closely relevant to the activation of MAPK and NF-κB pathways in the bystander U937 cells. When these two pathways in U937 cells were disturbed by special pharmacological inhibitors before cell co-culture, it was found that a NF-κB inhibitor of BAY 11-7082 further enhanced the proliferation inhibition and apoptosis induction in bystander U937 cells, but MAPK inhibitors of SP600125 and SB203580 protected cells from viability loss and apoptosis and U0126 presented more beneficial effect on cell protection. For α-irradiated epithelial cells, the activation of NF-κB and MAPK pathways in U937 cells participated in detrimental cellular responses since the above inhibitors could largely attenuate cell viability loss and apoptosis of irradiated cells. Our results demonstrated that there are bilateral bystander responses between irradiated lung epithelial cells and macrophages through MAPK and NF-κB signaling pathways, which accounts for the enhancement of α-irradiation induced damage.

  18. Diffusible Factors Secreted by Glioblastoma and Medulloblastoma Cells Induce Oxidative Stress in Bystander Neural Stem Progenitors.

    Science.gov (United States)

    Sharma, Neha; Colangelo, Nicholas W; de Toledo, Sonia M; Azzam, Edouard I

    2016-08-01

    Harmful effects that alter the homeostasis of neural stem or progenitor cells (NSPs) can affect regenerative processes in the central nervous system. We investigated the effect of soluble factors secreted by control or (137)Cs-γ-irradiated glioblastoma or medulloblastoma cells on redox-modulated endpoints in recipient human NSPs. Growth medium harvested from the nonirradiated brain tumor cells, following 24 h of growth, induced prominent oxidative stress in recipient NSPs as judged by overall increases in mitochondrial superoxide radical levels (p p21(Waf1) and p27(Kip1), and perturbations in cell cycle progression (p cells to radiation only slightly altered the induced oxidative changes in the bystander NSPs, except for medium from irradiated medulloblastoma cells that was more potent at inducing apoptosis in the NSPs than medium from nonirradiated cells (p cells is often used to support the growth of stem cells.

  19. A role for TRAIL/TRAIL-R2 in radiation-induced apoptosis and radiation-induced bystander response of human neural stem cells.

    Science.gov (United States)

    Ivanov, Vladimir N; Hei, Tom K

    2014-03-01

    Adult neurons, which are terminally differentiated cells, demonstrate substantial radioresistance. In contrast, human neural stem cells (NSC), which have a significant proliferative capacity, are highly sensitive to ionizing radiation. Cranial irradiation that is widely used for treatment of brain tumors may induce death of NSC and further cause substantial cognitive deficits such as impairing learning and memory. The main goal of our study was to determine a mechanism of NSC radiosensitivity. We observed a constitutive high-level expression of TRAIL-R2 in human NSC. On the other hand, ionizing radiation through generation of reactive oxygen species targeted cell signaling pathways and dramatically changed the pattern of gene expression, including upregulation of TRAIL. A significant increase of endogenous expression and secretion of TRAIL could induce autocrine/paracrine stimulation of the TRAIL-R2-mediated signaling cascade with activation of caspase-3-driven apoptosis. Furthermore, paracrine stimulation could initiate bystander response of non-targeted NSC that is driven by death ligands produced by directly irradiated NSC. Experiments with media transfer from directly irradiated NSC to non-targeted (bystander) NSC confirmed a role of secreted TRAIL for induction of a death signaling cascade in non-targeted NSC. Subsequently, TRAIL production through elimination of bystander TRAIL-R-positive NSC might substantially restrict a final yield of differentiating young neurons. Radiation-induced TRAIL-mediated apoptosis could be partially suppressed by anti-TRAIL antibody added to the cell media. Interestingly, direct gamma-irradiation of SK-N-SH human neuroblastoma cells using clinical doses (2-5 Gy) resulted in low levels of apoptosis in cancer cells that was accompanied however by induction of a strong bystander response in non-targeted NSC. Numerous protective mechanisms were involved in the maintenance of radioresistance of neuroblastoma cells, including

  20. Lack of evidence for low-LET radiation induced bystander response in normal human fibroblasts and colon carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Marianne B.; Goetz, Wilfried; Baulch, Janet E.; Pyles, Dinah N.; Dziegielewski, J.; Yovino, Susannah; Snyder, Andrew R.; de Toledo, S. M.; Azzam, Edouard I.; Morgan, William F.

    2010-02-01

    The conventional paradigm in radiation biology has been that DNA is the primary target for energy deposition following exposure to ionizing radiation. However, studies focusing on the non-target effects of radiation, i.e. effects occurring in cells not directly exposed to radiation, imply that the target of exposure is larger than what has traditionally been assumed and could have significant implications for radiation health risks. We have conducted an extensive study of the low-LET bystander effect including multiple cell lines and endpoints and various radiation sources and exposure scenarios. In no instance do we see evidence of a low-LET induced bystander effect. However, direct comparison for alpha particle exposure showed a statistically significant media transfer bystander effect for high-LET but not for low-LET radiation. From our results it is evident that there are many confounding factors mitigating bystander responses as reported in the literature and for the cell lines we studied that there is a LET dependence for the observed responses. Our observations reflect the inherent variability in biological systems and the difficulties in extrapolating from in vitro models to radiation risks in humans.

  1. Increased frequency of spontaneous neoplastic transformation in progeny of bystander cells from cultures exposed to densely ionizing radiation.

    Directory of Open Access Journals (Sweden)

    Manuela Buonanno

    Full Text Available An increased risk of carcinogenesis caused by exposure to space radiation during prolonged space travel is a limiting factor for human space exploration. Typically, astronauts are exposed to low fluences of ionizing particles that target only a few cells in a tissue at any one time. The propagation of stressful effects from irradiated to neighboring bystander cells and their transmission to progeny cells would be of importance in estimates of the health risks of exposure to space radiation. With relevance to the risk of carcinogenesis, we investigated, in model C3H 10T½ mouse embryo fibroblasts (MEFs, modulation of the spontaneous frequency of neoplastic transformation in the progeny of bystander MEFs that had been in co-culture 10 population doublings earlier with MEFs exposed to moderate doses of densely ionizing iron ions (1 GeV/nucleon or sparsely ionizing protons (1 GeV. An increase (P<0.05 in neoplastic transformation frequency, likely mediated by intercellular communication through gap junctions, was observed in the progeny of bystander cells that had been in co-culture with cells irradiated with iron ions, but not with protons.

  2. Small CD4 Mimetics Prevent HIV-1 Uninfected Bystander CD4+ T Cell Killing Mediated by Antibody-dependent Cell-mediated Cytotoxicity

    Directory of Open Access Journals (Sweden)

    Jonathan Richard

    2016-01-01

    Full Text Available Human immunodeficiency virus type 1 (HIV-1 infection causes a progressive depletion of CD4+ T cells. Despite its importance for HIV-1 pathogenesis, the precise mechanisms underlying CD4+ T-cell depletion remain incompletely understood. Here we make the surprising observation that antibody-dependent cell-mediated cytotoxicity (ADCC mediates the death of uninfected bystander CD4+ T cells in cultures of HIV-1-infected cells. While HIV-1-infected cells are protected from ADCC by the action of the viral Vpu and Nef proteins, uninfected bystander CD4+T cells bind gp120 shed from productively infected cells and are efficiently recognized by ADCC-mediating antibodies. Thus, gp120 shedding represents a viral mechanism to divert ADCC responses towards uninfected bystander CD4+ T cells. Importantly, CD4-mimetic molecules redirect ADCC responses from uninfected bystander cells to HIV-1-infected cells; therefore, CD4-mimetic compounds might have therapeutic utility in new strategies aimed at specifically eliminating HIV-1-infected cells.

  3. DNA damaging bystander signalling from stem cells, cancer cells and fibroblasts after Cr(VI) exposure and its dependence on telomerase

    Energy Technology Data Exchange (ETDEWEB)

    Cogan, Nicola [Bristol Implant Research Centre, University of Bristol, Bristol, BS10 5NB (United Kingdom); Baird, Duncan M. [Department of Pathology School of Medicine, Cardiff University, Henry Wellcome Building for Biomedical Research in Wales, Heath Park, Cardiff, CF14 4XN (United Kingdom); Phillips, Ryan [Bristol Implant Research Centre, University of Bristol, Bristol, BS10 5NB (United Kingdom); Crompton, Lucy A.; Caldwell, Maeve A. [Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, BS1 3NY (United Kingdom); Rubio, Miguel A. [Center of Regenerative Medicine in Barcelona, CMRB Dr. Aiguader, 88, 7th Floor, 08003 Barcelona (Spain); Newson, Roger [Radiation and Environmental Science Centre, Focas Institute, Dublin Institute of Technology, Dublin 2 (Ireland); Lyng, Fiona [National Heart and Lung Institute, Imperial College London, London, SW7 2AZ (United Kingdom); Case, C. Patrick, E-mail: c.p.case@bristol.ac.uk [Bristol Implant Research Centre, University of Bristol, Bristol, BS10 5NB (United Kingdom)

    2010-01-05

    The bystander effect is a feature of low dose radiation exposure and is characterized by a signaling process from irradiated cells to non irradiated cells, which causes DNA and chromosome damage in these 'nearest neighbour' cells. Here we show that a low and short dose of Cr(VI) can induce stem cells, cancer cells and fibroblasts to chronically secrete bystander signals, which cause DNA damage in neighboring cells. The Cr(VI) induced bystander signaling depended on the telomerase status of either cell. Telomerase negative fibroblasts were able to receive DNA damaging signals from telomerase positive or negative fibroblasts or telomerase positive cancer cells. However telomerase positive fibroblasts were resistant to signals from Cr(VI) exposed telomerase positive fibroblasts or cancer cells. Human embryonic stem cells, with positive Oct4 staining as a marker of pluripotency, showed no significant increase of DNA damage from adjacent Cr and mitomycin C exposed fibroblasts whilst those cells that were negatively stained did. This selectivity of DNA damaging bystander signaling could be an important consideration in developing therapies against cancer and in the safety and effectiveness of tissue engineering and transplantation using stem cells.

  4. Experimental verification for in vitro technique confirmation of bystander effect induced by gamma radiation in CHO-K1 cell line; Verificacao experimental para confirmacao da tecnica in vitro do efeito bystander induzido por radiacao gama na linhagem celular CHO-K1

    Energy Technology Data Exchange (ETDEWEB)

    Viana, P.H.L.; Goes, A.M.; Gomes, D.A., E-mail: pedroleroybio@hotmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento Bioquimica e Imunologia. Lab. de Imunologia Celular e Molecular; Grynberg, S.E., E-mail: seg@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-08-15

    The bystander effect refers to biological responses detected in cells not directly irradiated but influenced, somehow, by signals transmitted from neighboring irradiated cells. These biological responses include sister chromatid exchange, mutations, micronucleus formation, chromosomal aberrations, carcinogenesis, apoptosis and necrosis. Although its existence is unquestionable, the mechanisms involved on triggering the bystander effect are not yet completely elucidated. Previous studies have shown that the bystander effect depends on a large variety of parameters including the radiation dose, the dose rate, the type of radiation and type of cells or tissue. This study aims to confirm the technique previously used in the literature in human cell lines for the bystander effect verification. The results suggest that the working conditions adopted by the group show technical efficiency and enables the reproduction of the bystander effect. (author)

  5. Signaling factors and pathways of α-particle irradiation induced bilateral bystander responses between Beas-2B and U937 cells

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiamei; Wang, Juan; Wang, Xiangdong; Wang, Ping; Xu, Jinping; Zhou, Cuiping; Bai, Yang; Shao, Chunlin, E-mail: clshao@shmu.edu.cn

    2016-07-15

    Highlights: • Radiation damage of Beas-2B cells was enhanced by macrophage-mediated bilateral bystander responses. • Expressions of TNF-α and IL-8 in the α-irradiated Beas-2B cells were dependent on ERK and p38 pathways. • The neighboring U937 cells further increased the generation of TNF-α and IL-8 in the α-irradiated Beas-2B cells. • NF-κB dependent upregulation of TNF-α and IL-8 was induced in the bystander U937 cells. - Abstract: Although radiation induced bystander effects (RIBE) have been investigated for decades for their potential health risk, the underlying gene regulation is still largely unclear, especially the roles of immune system and inflammatory response in RIBE. In the present study, macrophage U937 cells and epithelial Beas-2B cells were co-cultured to disclose the cascades of bystander signaling factors and intercellular communications. After α-particle irradiation, both ERK and p38 pathways were activated in Beas-2B cells and were associated with the autocrine and paracrine signaling of TNF-α and IL-8, resulting in direct damage to the irradiated cells. Similar upregulation of TNF-α and IL-8 was induced in the bystander U937 cells after co-culture with α-irradiated Beas-2B cells. This upregulation was dependent on the activation of NF-κB pathway and was responsible for the enhanced damage of α-irradiated Beas-2B cells. Interestingly, the increased expressions of TNF-α and IL-8 mRNAs in the bystander U937 cells were clearly relayed on the activated ERK and p38 pathways in the irradiated Beas-2B cells, and the upregulation of TNF-α and IL-8 mRNAs in co-cultured Beas-2B cells was also partly due to the activated NF-κB pathway in the bystander U937 cells. With the pretreatment of U0126 (MEK1/2 inhibitor), SB203580 (p38 inhibitor) or BAY 11-7082 (NF-κB inhibitor), the aggravated damage in the α-irradiated Beas-2B cells could be largely alleviated. Our results disclosed novel signaling cascades of macrophage-mediated bilateral

  6. Coexpressed Catalase Protects Chimeric Antigen Receptor-Redirected T Cells as well as Bystander Cells from Oxidative Stress-Induced Loss of Antitumor Activity.

    Science.gov (United States)

    Ligtenberg, Maarten A; Mougiakakos, Dimitrios; Mukhopadhyay, Madhura; Witt, Kristina; Lladser, Alvaro; Chmielewski, Markus; Riet, Tobias; Abken, Hinrich; Kiessling, Rolf

    2016-01-15

    Treatment of cancer patients by adoptive T cell therapy has yielded promising results. In solid tumors, however, T cells encounter a hostile environment, in particular with increased inflammatory activity as a hallmark of the tumor milieu that goes along with abundant reactive oxygen species (ROS) that substantially impair antitumor activity. We present a strategy to render antitumor T cells more resilient toward ROS by coexpressing catalase along with a tumor specific chimeric Ag receptor (CAR) to increase their antioxidative capacity by metabolizing H2O2. In fact, T cells engineered with a bicistronic vector that concurrently expresses catalase, along with the CAR coexpressing catalase (CAR-CAT), performed superior over CAR T cells as they showed increased levels of intracellular catalase and had a reduced oxidative state with less ROS accumulation in both the basal state and upon activation while maintaining their antitumor activity despite high H2O2 levels. Moreover, CAR-CAT T cells exerted a substantial bystander protection of nontransfected immune effector cells as measured by CD3ζ chain expression in bystander T cells even in the presence of high H2O2 concentrations. Bystander NK cells, otherwise ROS sensitive, efficiently eliminate their K562 target cells under H2O2-induced oxidative stress when admixed with CAR-CAT T cells. This approach represents a novel means for protecting tumor-infiltrating cells from tumor-associated oxidative stress-mediated repression.

  7. Bystander effects elicited by single-cell photo-oxidative blue-light stimulation in retinal pigment epithelium cell networks

    Science.gov (United States)

    Ishii, Masaaki; Rohrer, Bärbel

    2017-01-01

    Bystander effect’ refers to the induction of biological effects in cells not directly targeted. The retinal pigment epithelium consists of hexagonal cells, forming a monolayer interconnected by gap junctions (GJs). Oxidative stress initiated in an individual cell by photostimulation (488 nm) triggered changes in reactive oxygen species (ROS), Ca2+ and mitochondrial membrane potential (ψm). The Ca2+ signal was transmitted to neighboring cells slowly and non-uniformly; the ROS signal spread fast and radially. Increased Ca2+ levels were associated with a loss in ψm. GJ blockers prevented the spreading of the Ca2+, but not the ROS-related signal. The GJ-mediated Ca2+ wave was associated with cell death by 24 h, requiring endoplasmic reticulum–mitochondria Ca2+ transfer. Ensuing cell death was correlated with baseline Ca2+ levels, and baseline Ca2+ levels were correlated with pigmentation. Hence, local oxidative stress in a donor cell can trigger changes in certain connected recipient cells, a signal that required GJ communication and an ROS-Ca2+ dual-hit. Finally, damage apparently occurred in susceptible cells, which correlated with baseline Ca2+ levels. PMID:28179989

  8. The engineered thymidylate kinase (TMPK)/AZT enzyme-prodrug axis offers efficient bystander cell killing for suicide gene therapy of cancer.

    Science.gov (United States)

    Sato, Takeya; Neschadim, Anton; Lavie, Arnon; Yanagisawa, Teruyuki; Medin, Jeffrey A

    2013-01-01

    We previously described a novel suicide (or 'cell fate control') gene therapy enzyme/prodrug system based on an engineered variant of human thymidylate kinase (TMPK) that potentiates azidothymidine (AZT) activation. Delivery of a suicide gene sequence into tumors by lentiviral transduction embodies a cancer gene therapy that could employ bystander cell killing as a mechanism driving significant tumor regression in vivo. Here we present evidence of a significant bystander cell killing in vitro and in vivo mediated by the TMPK/AZT suicide gene axis that is reliant on the formation of functional gap-junctional intercellular communications (GJICs). Potentiation of AZT activation by the engineered TMPK expressed in the human prostate cancer cell line, PC-3, resulted in effective bystander killing of PC-3 cells lacking TMPK expression--an effect that could be blocked by the GJIC inhibitor, carbenoxolone. Although GJICs are mainly formed by connexins, a new family of GJIC molecules designated pannexins has been recently identified. PC-3 cells expressed both connexin43 (Cx43) and Pannexin1 (Panx1), but Panx1 expression predominated at the plasma membrane, whereas Cx43 expression was primarily localized to the cytosol. The contribution of bystander effects to the reduction of solid tumor xenografts established by the PC-3 cell line was evaluated in an animal model. We demonstrate the contribution of bystander cell killing to tumor regression in a xenograft model relying on the delivery of expression of the TMPK suicide gene into tumors via direct intratumoral injection of recombinant therapeutic lentivirus. Taken together, our data underscore that the TMPK/AZT enzyme-prodrug axis can be effectively utilized in suicide gene therapy of solid tumors, wherein significant tumor regression can be achieved via bystander effects mediated by GJICs.

  9. The engineered thymidylate kinase (TMPK/AZT enzyme-prodrug axis offers efficient bystander cell killing for suicide gene therapy of cancer.

    Directory of Open Access Journals (Sweden)

    Takeya Sato

    Full Text Available We previously described a novel suicide (or 'cell fate control' gene therapy enzyme/prodrug system based on an engineered variant of human thymidylate kinase (TMPK that potentiates azidothymidine (AZT activation. Delivery of a suicide gene sequence into tumors by lentiviral transduction embodies a cancer gene therapy that could employ bystander cell killing as a mechanism driving significant tumor regression in vivo. Here we present evidence of a significant bystander cell killing in vitro and in vivo mediated by the TMPK/AZT suicide gene axis that is reliant on the formation of functional gap-junctional intercellular communications (GJICs. Potentiation of AZT activation by the engineered TMPK expressed in the human prostate cancer cell line, PC-3, resulted in effective bystander killing of PC-3 cells lacking TMPK expression--an effect that could be blocked by the GJIC inhibitor, carbenoxolone. Although GJICs are mainly formed by connexins, a new family of GJIC molecules designated pannexins has been recently identified. PC-3 cells expressed both connexin43 (Cx43 and Pannexin1 (Panx1, but Panx1 expression predominated at the plasma membrane, whereas Cx43 expression was primarily localized to the cytosol. The contribution of bystander effects to the reduction of solid tumor xenografts established by the PC-3 cell line was evaluated in an animal model. We demonstrate the contribution of bystander cell killing to tumor regression in a xenograft model relying on the delivery of expression of the TMPK suicide gene into tumors via direct intratumoral injection of recombinant therapeutic lentivirus. Taken together, our data underscore that the TMPK/AZT enzyme-prodrug axis can be effectively utilized in suicide gene therapy of solid tumors, wherein significant tumor regression can be achieved via bystander effects mediated by GJICs.

  10. Homeostatic 'bystander' proliferation of human peripheral blood B cells in response to polyclonal T-cell stimulation in vitro.

    Science.gov (United States)

    Jasiulewicz, Aleksandra; Lisowska, Katarzyna A; Pietruczuk, Krzysztof; Frąckowiak, Joanna; Fulop, Tamas; Witkowski, Jacek M

    2015-11-01

    The mechanisms of maintenance of adequate numbers of B lymphocytes and of protective levels of immunoglobulins in the absence of antigenic (re)stimulation remain not fully understood. Meanwhile, our results presented here show that both peripheral blood naive and memory B cells can be activated strongly and non-specifically (in a mitogen-like fashion) in 5-day in vitro cultures of anti-CD3- or concanavalin A (Con A)-stimulated peripheral blood mononuclear cells of healthy people. This polyclonal, bystander activation of the B cells includes multiple divisions of most of them (assessed here by the flow cytometric technique of dividing cell tracking) and significant antibody [immunoglobulin M (IgM) and IgG] secretion. Observed proliferation of the CD19(+) B cells depends on contact with stimulated T helper (Th) cells (via CD40-CD40L interaction) and on the response of B cells to secreted interleukins IL-5, IL-10 and IL-4, and is correlated with the levels of these Th-derived molecules, while it does not involve the ligation of the BCR/CD19 complex. We suggest that the effect might reflect the situation occurring in vivo as the homeostatic proliferation of otherwise non-stimulated, peripheral B lymphocytes, providing an always ready pool for efficient antibody production to any new (or cognate) antigen challenge.

  11. Low doses of alpha particles do not induce sister chromatid exchanges in bystander Chinese hamster cells defective in homologous recombination

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, H; Wilson, P F; Chen, D J; Thompson, L H; Bedford, J S; Little, J B

    2007-10-26

    We reported previously that the homologous recombinational repair (HRR)-deficient Chinese hamster mutant cell line irs3 (deficient in the Rad51 paralog Rad51C) showed only a 50% spontaneous frequency of sister chromatid exchange (SCE) as compared to parental wild-type V79 cells. Furthermore, when irradiated with very low doses of alpha particles, SCEs were not induced in irs3 cells, as compared to a prominent bystander effect observed in V79 cells (Nagasawa et al., Radiat. Res. 164, 141-147, 2005). In the present study, we examined additional Chinese hamster cell lines deficient in the Rad51 paralogs Rad51C, Rad51D, Xrcc2, and Xrcc3 as well as another essential HRR protein, Brca2. Spontaneous SCE frequencies in non-irradiated wild-type cell lines CHO, AA8 and V79 were 0.33 SCE/chromosome, whereas two Rad51C-deficient cell lines showed only 0.16 SCE/chromosome. Spontaneous SCE frequencies in cell lines defective in Rad51D, Xrcc2, Xrcc3, and Brca2 ranged from 0.23-0.33 SCE/chromosome, 0-30% lower than wild-type cells. SCEs were induced significantly 20-50% above spontaneous levels in wild-type cells exposed to a mean dose of 1.3 mGy of alpha particles (<1% of nuclei traversed by an alpha particle). However, induction of SCEs above spontaneous levels was minimal or absent after {alpha}-particle irradiation in all of the HRR-deficient cell lines. These data suggest that Brca2 and the Rad51 paralogs contribute to DNA damage repair processes induced in bystander cells (presumably oxidative damage repair in S-phase cells) following irradiation with very low doses of alpha particles.

  12. Surface-assembled poly(I:C) on PEGylated PLGA microspheres as vaccine adjuvant: APC activation and bystander cell stimulation.

    Science.gov (United States)

    Hafner, Annina M; Corthésy, Blaise; Textor, Marcus; Merkle, Hans P

    2016-11-30

    Biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres are potential vehicles to deliver antigens for vaccination. Because they lack the full capacity to activate professional antigen presenting cells (APCs), combination with an immunostimulatory adjuvant may be considered. A candidate is the synthetic TLR3 ligand polyriboinosinic acid-polyribocytidylic acid, poly(I:C), which drives cell-mediated immunity. However, poly(I:C) has also been linked to the pathogenesis of autoimmunity, as affected by widespread stimulation of non-hematopoietic bystander cells. To address this aspect, we propose to minimize the poly(I:C) dose as well as to control the stimulation of non-immune bystander cells by poly(I:C). To facilitate the maturation of APCs with minimal poly(I:C) doses, we surface-assembled poly(I:C) onto PLGA microspheres. The microspheres' surface was further modified by poly(ethylene glycol) (PEG) coronas with varying PEG-densities. PLGA microspheres loaded with tetanus toxoid (tt) as model antigen were manufactured by microextrusion-based solvent extraction. The negatively charged PLGA(tt) microspheres were coated with polycationic poly(l-lysine) (PLL) polymers, either PLL itself or PEG-grafted PLL (PLL-g-PEG) with varying grafting ratios (g=2.2 and g=10.1). Stable surface assembly of poly(I:C) was achieved by subsequent incubation of polymer-coated PLGA microspheres with aqueous poly(I:C) solutions. We evaluated the immunostimulatory potential of such PLGA(tt) microsphere formulations on monocyte-derived dendritic cells (MoDCs) as well as human foreskin fibroblasts (HFFs) as model for non-hematopoietic bystander cells. Formulations with surface-assembled poly(I:C) readily activated MoDCs with respect to the expression of maturation-related surface markers, proinflammatory cytokine secretion and directed migration. When surface-assembled, poly(I:C) enhanced its immunostimulatory activity by more than one order of magnitude as compared to free poly

  13. Bystander Effects of Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Little, John B. [Harvard T.H. Chan School of Public Health, Boston, MA (United States). Dept. of Genetics and Complex Diseases

    2017-01-17

    The objectives of this grant renewal are to provide administrative support and travel funds to allow the continued participation of the principal investigator (Dr. John B. Little) as an advisor to research initiated by several research fellows from his laboratory. The actual research will be carried out under the direction of Dr. Hatsumi Nagasawa with the collaboration of Dr. Joel Bedford at the Colorado State University, and by Drs. Edouard Azzam and Sonia de Toledo at the University of Medicine and Dentistry of New Jersey. Dr. Little will advise on the planning of experiments and development of experimental protocols, the analysis of data, and the preparation of manuscripts for publication. The Specific Aims for several of the planned experiments include: 1) to extend studies of the role of recombinational repair in the bystander effect by examining other genes in this pathway and cell lines deficient in excision repair; 2) to continue studies to determine the nature of the damage signal transmitted to bystander cells including the expression of several connexins in the bystander response, and the extent to which the enhanced oxidative metabolism observed in bystander cells may relate to the nature of the transmitted bystander signal; 3) to utilize a genome-wide approach to examine the genetic basis for the hypersensitivity to ionization we have observed in unaffected parents of patients with hereditary retinoblastoma, as well as from a group of a apparently normal individuals that show similar radiosensitivity; 4) to complete studies concerning the induction of high frequencies of cells with massive chromosome damage in clonal derivatives of p53 and p21 knockout mouse cell lines; in particular to examine the role of telomere changes in this phenomenon. Overall, the results of these studies should enhance our understanding of the risk of low dose exposures to ionizing radiation, including human populations to residential radon as well as occupational exposures.

  14. Novel mechanism for the radiation-induced bystander effect: Nitric oxide and ethylene determine the response in sponge cells

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Werner E.G. [Institut fuer Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universitaet, Duesbergweg 6, D-55099 Mainz (Germany)]. E-mail: wmueller@uni-mainz.de; Ushijima, Hiroshi [Department of Developmental Medical Sciences, Institute of International Health, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-0033 (Japan); Batel, Renato [Center for Marine Research, ' Ruder Boskovic' Institute, HR-52210 Rovinj (Croatia); Krasko, Anatoli [Institut fuer Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universitaet, Duesbergweg 6, D-55099 Mainz (Germany); Borejko, Alexandra [Institut fuer Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universitaet, Duesbergweg 6, D-55099 Mainz (Germany); Mueller, Isabel M. [Institut fuer Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universitaet, Duesbergweg 6, D-55099 Mainz (Germany); Schroeder, Heinz-C. [Institut fuer Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universitaet, Duesbergweg 6, D-55099 Mainz (Germany)

    2006-05-11

    Until now the bystander effect had only been described in vertebrates. In the present study the existence of this effect has been demonstrated for the phylogenetically oldest metazoan phylum, the Porifera. We used the demosponge Suberites domuncula for the experiments in the two-chamber-system. The lower dish contained irradiated 'donor' cells (single cells) and the upper dish the primmorphs ('recipient' primmorphs). The 'donor' cells were treated with UV-B light (40 mJ/cm{sup 2}) and 100 {mu}M hydrogen peroxide (H{sub 2}O{sub 2}), factors that exist also in the natural marine aquatic environment of sponges; these factors caused a high level of DNA strand breaks followed by a reduced viability of the cells. If these cells were added to the 'recipient' primmorphs these 3D-cell cultures started to undergo apoptosis. This effect could be abolished by the NO-specific scavenger PTIO and ethylene. The conclusion that NO is synthesized by the UV-B/H{sub 2}O{sub 2}-treated cells was supported analytically. The cDNA encoding the enzyme dimethylarginine dimethylaminohydrolase (DDAH) was isolated from the 'donor' cells. High levels of DDAH transcripts were measured in UV-B/H{sub 2}O{sub 2}-treated 'donor' cells while after ethylene treatment the steady-state level of expression drops drastically. We conclude that in the absence of ethylene the concentration of the physiological inhibitor for the NO synthase ADMA is low, due to the high level of DDAH. In consequence, high amounts of NO are released from 'donor' cells which cause apoptosis in 'recipient' primmorphs. In contrast, ethylene reduces the DDAH expression with the consequence of higher levels of ADMA which prevent the formation of larger amounts of NO. This study describes the radiation-induced bystander effect also for the most basal metazoans and demonstrates that this effect is controlled by the two gasses NO and ethylene.

  15. Bystander effect-induced mutagenicity in HPRT locus of CHO cells following BNCT neutron irradiation: Characteristics of point mutations by sequence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kinashi, Yuko [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka (Japan)], E-mail: kinashi@rri.kyoto-u.ac.jp; Suzuki, Minoru; Masunaga, Shinichiro; Ono, Koji [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka (Japan)

    2009-07-15

    To investigate bystander mutagenic effects induced by alpha particles during boron neutron capture therapy (BNCT), we mixed cells that were electroporated with borocaptate sodium (BSH), which led to the accumulation of {sup 10}B inside the cells, with cells that did not contain the boron compound. BSH-containing cells were irradiated with {alpha} particles produced by the {sup 10}B(n,{alpha}){sup 7}Li reaction, whereas cells without boron were only affected by the {sup 1}H(n,{gamma}){sup 2}H and {sup 14}N(n,{rho}){sup 14}C reactions. The frequency of mutations induced in the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus was examined in Chinese hamster ovary (CHO) cells irradiated with neutrons (Kyoto University Research Reactor: 5 MW). Neutron irradiation of 1:1 mixtures of cells with and without BSH resulted in a survival fraction of 0.1, and the cells that did not contain BSH made up 99.4% of the surviving cell population. Using multiplex polymerase chain reactions (PCRs), molecular structural analysis indicated that most of the mutations induced by the bystander effect were point mutations and that the frequencies of total and partial deletions induced by the bystander effect were lower than those resulting from the {alpha} particles produced by the {sup 10}B(n,{alpha}){sup 7}Li reaction or the neutron beam from the {sup 1}H(n,{gamma}){sup 2}H and {sup 14}N(n,{rho}){sup 14}C reactions. The types of point mutations induced by the BNCT bystander effect were analyzed by cloning and sequencing methods. These mutations were comprised of 65.5% base substitutions, 27.5% deletions, and 7.0% insertions. Sequence analysis of base substitutions showed that transversions and transitions occurred in 64.7% and 35.3% of cases, respectively. G:C{yields}T:A transversion induced by 8-oxo-guanine in DNA occurred in 5.9% of base substitution mutants in the BNCT bystander group. The characteristic mutations seen in this group, induced by BNCT {alpha} particles

  16. Monitoring G protein-coupled receptor and β-arrestin trafficking in live cells using enhanced bystander BRET

    Science.gov (United States)

    Namkung, Yoon; Le Gouill, Christian; Lukashova, Viktoria; Kobayashi, Hiroyuki; Hogue, Mireille; Khoury, Etienne; Song, Mideum; Bouvier, Michel; Laporte, Stéphane A.

    2016-01-01

    Endocytosis and intracellular trafficking of receptors are pivotal to maintain physiological functions and drug action; however, robust quantitative approaches are lacking to study such processes in live cells. Here we present new bioluminescence resonance energy transfer (BRET) sensors to quantitatively monitor G protein-coupled receptors (GPCRs) and β-arrestin trafficking. These sensors are based on bystander BRET and use the naturally interacting chromophores luciferase (RLuc) and green fluorescent protein (rGFP) from Renilla. The versatility and robustness of this approach are exemplified by anchoring rGFP at the plasma membrane or in endosomes to generate high dynamic spectrometric BRET signals on ligand-promoted recruitment or sequestration of RLuc-tagged proteins to, or from, specific cell compartments, as well as sensitive subcellular BRET imaging for protein translocation visualization. These sensors are scalable to high-throughput formats and allow quantitative pharmacological studies of GPCR trafficking in real time, in live cells, revealing ligand-dependent biased trafficking of receptor/β-arrestin complexes. PMID:27397672

  17. Cytokine profile of conditioned medium from human tumor cell lines after acute and fractionated doses of gamma radiation and its effect on survival of bystander tumor cells.

    Science.gov (United States)

    Desai, Sejal; Kumar, Amit; Laskar, S; Pandey, B N

    2013-01-01

    Cytokines are known to play pivotal roles in cancer initiation, progression and pathogenesis. Accumulating evidences suggest differences in basal and stress-induced cytokine profiles of cancers with diverse origin. However, a comprehensive investigation characterising the cytokine profile of various tumor types after acute and fractionated doses of gamma-irradiation, and its effect on survival of bystander cells is not well known in literature. In the present study, we have evaluated the cytokine secretion profile of human tumor cell lines (HT1080, U373MG, HT29, A549 and MCF-7) either before (basal) or after acute (2, 6 Gy) and fractionated doses (3×2 Gy) of gamma-irradiation in culture medium obtained from these cells by multiplex bead array/ELISA. Moreover, clonogenic assays were performed to evaluate the effect of conditioned medium (CM) on the survival and growth of respective cells. Based on the screening of 28 analytes, our results showed that the basal profiles of these cell lines varied considerably in terms of the number and magnitude of secreted factors, which was minimum in MCF-7. Interestingly, TNF-α, IL-1β, PDGF-AA, TGF-β1, fractalkine, IL-8, VEGF and GCSF were found in CM of all the cell lines. However, secretion of certain cytokines was cell line-specific. Moreover, CM caused increase in clonogenic survival of respective tumor cells (in the order HT1080>U373MG>HT29>A549>MCF-7), which was correlated with the levels of IL-1β, IL-6, IL-8, GMCSF and VEGF in their CM. After irradiation, the levels of most of the cytokines increased markedly in a dose dependent manner. The fold change in cytokine levels was lower in irradiated conditioned medium (ICM) of tumor cells collected after fractionated than respective acute dose, except in MCF-7. Interestingly, amongst these cell lines, the radiation-induced fold increase in cytokine levels was maximum in ICM of A549 cells. Moreover, bystander A549 cells treated with respective ICM showed dose dependent

  18. Low Dose Studies with Focused X-Rays in cell and Tissue Models: Mechanisms of Bystander and Genomic Instability Responses

    Energy Technology Data Exchange (ETDEWEB)

    Kathy Held; Kevin Prise; Barry Michael; Melvyn Folkard

    2002-12-14

    the biological ha sis of the relationship between high- and low-dose exposures. The targeting approach also allows us to study very clearly a newly recognized effect of radiation, the ''bystander effect'', which appears to dominate some low-dose responses and therefore may have a significant role in low-dose risk mechanisms. Our project also addresses the concept that the background of naturally occurring oxidative damage that takes place continually in cells due to byproducts of metabolism may play a role in low-dose radiation risk. This project therefore also examines how cells are damaged by treatments that modify the levels of oxidative damage, either alone or in combination with low-dose irradiation. In this project, we have used human and rodent cell lines and each set of experiments has been carried out on a single cell type. However, low-dose research has to extend into tissues because signaling between cells of different types is likely to influence the responses. Our studies have therefore also included microbeam experiments using a model tissue system that consists of an explant of a small piece of pig ureter grown in culture. The structure of this tissue is similar to that of epithelium and therefore it relates to the tissues in which carcinoma arises. Our studies have been able to measure bystander-induced changes in the cells growing out from the tissue fragment after it has been targeted with a few radiation tracks to mimic a low-dose exposure.

  19. Low Dose Studies with Focused X-rays in Cell and Tissue Models: Mechanisms of Bystander and Genomic Instability Responses

    Energy Technology Data Exchange (ETDEWEB)

    Barry D. Michael; Kathryn Held; Kevin Prise

    2002-12-19

    study the biological basis of the relationship between high- and low-dose exposures. The targeting approach also allows us to study very clearly a newly recognized effect of radiation, the ''bystander effect'', which appears to dominate some low-dose responses and therefore may have a significant role in low-dose risk mechanisms. Our project also addresses the concept that the background of naturally occurring oxidative damage that takes place continually in cells due to byproducts of metabolism may play a role in treatments that modify the levels of oxidative damage, either alone or in combination with low-dose irradiation. In this project, we have used human and rodent cell lines and each set of experiments has been carried out on a single cell type. However, low-dose research has to extend into tissues because signaling between cells of different types is likely to influence the responses. Our studies have therefore also included microbeam experiments using a model tissue system that consists of an explant of a small piece of pig ureter grown in culture. The structure of this tissue is similar to that of epithelium and there it relates to the tissues in which carcinoma arises. Our studies have been able to measure bystander-induced changes in the cells growing out from the tissue fragment after it has been targeted with a few radiation tracks to mimic a low-dose exposure.

  20. Regulatory T-cells in chronic lymphocytic leukemia: actor or innocent bystander?

    Science.gov (United States)

    D’Arena, Giovanni; Simeon, Vittorio; D’Auria, Fiorella; Statuto, Teodora; Sanzo, Paola Di; Martino, Laura De; Marandino, Aurelio; Sangiorgio, Michele; Musto, Pellegrino; Feo, Vincenzo De

    2013-01-01

    Regulatory T (Treg) cells are now under extensive investigation in chronic lymphocytic leukemia (CLL). This small subset of T-cells has been, in fact, considered to be involved in the pathogenesis and progression of CLL. However, whether Treg dysregulation in CLL plays a key role or it rather represents a simple epiphenomenon is still matter of debate. In the former case, Treg cells could be appealing for targeting therapies. Finally, Treg cells have also been proposed as a prognostic indicator of the disease clinical course. PMID:23358515

  1. Mitochondrial mutagenesis induced by tumor-specific radiation bystander effects.

    LENUS (Irish Health Repository)

    Gorman, Sheeona

    2012-02-01

    The radiation bystander effect is a cellular process whereby cells not directly exposed to radiation display cellular alterations similar to directly irradiated cells. Cellular targets including mitochondria have been postulated to play a significant role in this process. In this study, we utilized the Random Mutation Capture assay to quantify the levels of random mutations and deletions in the mitochondrial genome of bystander cells. A significant increase in the frequency of random mitochondrial mutations was found at 24 h in bystander cells exposed to conditioned media from irradiated tumor explants (p = 0.018). CG:TA mutations were the most abundant lesion induced. A transient increase in the frequency of random mitochondrial deletions was also detected in bystander cells exposed to conditioned media from tumor but not normal tissue at 24 h (p = 0.028). The increase in both point mutations and deletions was transient and not detected at 72 h. To further investigate mitochondrial dysfunction, mitochondrial membrane potential and reactive oxygen species were assessed in these bystander cells. There was a significant reduction in mitochondrial membrane potential and this was positively associated with the frequency of random point mutation and deletions in bystander cells treated with conditioned media from tumor tissue (r = 0.71, p = 0.02). This study has shown that mitochondrial genome alterations are an acute consequence of the radiation bystander effect secondary to mitochondrial dysfunction and suggests that this cannot be solely attributable to changes in ROS levels alone.

  2. Genomic instability in liver cells caused by an LPS-induced bystander-like effect.

    Directory of Open Access Journals (Sweden)

    Igor Kovalchuk

    Full Text Available Bacterial infection has been linked to carcinogenesis, however, there is lack of knowledge of molecular mechanisms that associate infection with the development of cancer. We analyzed possible effects of the consumption of heat-killed E. coli O157:H7 cells or its cellular components, DNA, RNA, protein or lipopolysaccharides (LPS on gene expression in naïve liver cells. Four week old mice were provided water supplemented with whole heat-killed bacteria or bacterial components for a two week period. One group of animals was sacrificed immediately, whereas another group was allowed to consume uncontaminated tap water for an additional two weeks, and liver samples were collected, post mortem. Liver cells responded to exposure of whole heat-killed bacteria and LPS with alteration in γH2AX levels and levels of proteins involved in proliferation, DNA methylation (MeCP2, DNMT1, DNMT3A and 3B or DNA repair (APE1 and KU70 as well as with changes in the expression of genes involved in stress response, cell cycle control and bile acid biosynthesis. Other bacterial components analysed in this study did not lead to any significant changes in the tested molecular parameters. This study suggests that lipopolysaccharides are a major component of Gram-negative bacteria that induce molecular changes within naïve cells of the host.

  3. Real-time Molecular Study of Bystander Effects of Low dose Low LET radiation Using Living Cell Imaging and Nanoparticale Optics

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, Mohan [UT Health Science Center at San Antonio; Xu, Nancy R [Old Dominion University; Mohan, Sumathy [UT Health Science Center at San Antonio

    2013-06-03

    In this study two novel approaches are proposed to investigate precisely the low dose low LET radiation damage and its effect on bystander cells in real time. First, a flow shear model system, which would provide us a near in vivo situation where endothelial cells in the presence of extra cellular matrix experiencing continuous flow shear stress, will be used. Endothelial cells on matri-gel (simulated extra cellular matrix) will be subjected to physiological flow shear (that occurs in normal blood vessels). Second, a unique tool (Single nano particle/single live cell/single molecule microscopy and spectroscopy; Figure A) will be used to track the molecular trafficking by single live cell imaging. Single molecule chemical microscopy allows one to single out and study rare events that otherwise might be lost in assembled average measurement, and monitor many target single molecules simultaneously in real-time. Multi color single novel metal nanoparticle probes allow one to prepare multicolor probes (Figure B) to monitor many single components (events) simultaneously and perform multi-complex analysis in real-time. These nano-particles resist to photo bleaching and hence serve as probes for unlimited timeframe of analysis. Single live cell microscopy allows one to image many single cells simultaneously in real-time. With the combination of these unique tools, we will be able to study under near-physiological conditions the cellular and sub-cellular responses (even subtle changes at one molecule level) to low and very low doses of low LET radiation in real time (milli-second or nano-second) at sub-10 nanometer spatial resolution. This would allow us to precisely identify, at least in part, the molecular mediators that are responsible of radiation damage in the irradiated cells and the mediators that are responsible for initiating the signaling in the neighboring cells. Endothelial cells subjected to flow shear (2 dynes/cm2 or 16 dynes/cm2) and exposed to 0.1, 1 and 10

  4. Intranasal delivery of cholera toxin induces th17-dominated T-cell response to bystander antigens.

    Directory of Open Access Journals (Sweden)

    Jee-Boong Lee

    Full Text Available Cholera toxin (CT is a potent vaccine adjuvant, which promotes mucosal immunity to protein antigen given by nasal route. It has been suggested that CT promotes T helper type 2 (Th2 response and suppresses Th1 response. We here report the induction of Th17-dominated responses in mice by intranasal delivery of CT. This dramatic Th17-driving effect of CT, which was dependent on the B subunit, was observed even in Th1 or Th2-favored conditions of respiratory virus infection. These dominating Th17 responses resulted in the significant neutrophil accumulation in the lungs of mice given CT. Both in vitro and in vivo treatment of CT induced strongly augmented IL-6 production, and Th17-driving ability of CT was completely abolished in IL-6 knockout mice, indicating a role of this cytokine in the Th17-dominated T-cell responses by CT. These data demonstrate a novel Th17-driving activity of CT, and help understand the mechanisms of CT adjuvanticity to demarcate T helper responses.

  5. Radiation-induced bystander effects in vivo are sex specific

    Energy Technology Data Exchange (ETDEWEB)

    Koturbash, Igor; Kutanzi, Kristy; Hendrickson, Karl; Rodriguez-Juarez, Rocio; Kogosov, Dmitry [Department of Biological Sciences, University of Lethbridge, Alberta T1K 3M4 (Canada); Kovalchuk, Olga [Department of Biological Sciences, University of Lethbridge, Alberta T1K 3M4 (Canada)], E-mail: olga.kovalchuk@uleth.ca

    2008-07-03

    Ionizing radiation (IR) effects span beyond the area of direct exposure and can be observed in neighboring and distant naive cells and organs. This phenomenon is termed a 'bystander effect'. IR effects in directly exposed tissue in vivo are epigenetically mediated and distinct in males and females. Yet, IR-induced bystander effects have never been explored in a sex-specificity domain. We used an in vivo mouse model, whereby the bystander effects are studied in spleen of male and female animals subjected to head exposure when the rest of the body is protected by a medical-grade lead shield. We analyzed the induction of DNA damage and alterations in global DNA methylation. Molecular parameters were correlated with cellular proliferation and apoptosis levels. The changes observed in bystander organs are compared to the changes in unexposed animals and animals exposed to predicted and measured scatter doses. We have found the selective induction of DNA damage levels, global DNA methylation, cell proliferation and apoptosis in exposed and bystander spleen tissue of male and female mice. Sex differences were significantly diminished in animals subjected to a surgical removal of gonads. These data constitute the first evidence of sex differences in radiation-induced bystander effects in mouse spleen in vivo. We show the role of sex hormones in spleen bystander responses and discuss implications of the observed changes.

  6. Microbeam facility extension for single-cell irradiation experiments. Investigations about bystander effect and reactive oxygen species impact

    Energy Technology Data Exchange (ETDEWEB)

    Hanot, M.; Khodja, H.; Daudin, L.; Hoarau, J.; Carriere, M.; Gouget, B. [CEA Saclay, Lab. Pierre Sue (LPS), CEA-CNRS UMR9956, 91 - Gif-sur-Yvette (France)

    2006-07-01

    The LPS microbeam facility is based on a KN3750 Van de Graaff accelerator devoted to microbeam analysis [1]. It is equipped with two horizontal microbeam lines used in various fields such as material science, geological science, nuclear material science and biology. Since two years, a single ion hit device is being developed at the LPS. The setup is dedicated to the study of ionizing radiation effects on living cells by performing single ion irradiation at controlled doses and locations. This study will complete current researches conducted on uranium chemical toxicity on renal an d osteoblastic cells. After ingestion, most uranium is excreted from the body within a few days except small fraction that is absorbed into the blood-stream (0.2 to 5%) and then deposit and preferentially in kidneys and bones, where it can remain for many years. Uranium is a heavy metal and a primarily alpha emitter. It can lead to bone cancer as a result of the ionizing radiation associated with the radioactive decay products. The study of the response to an exposure to alpha particles will permit to distinguish radiotoxicity and chemical toxicity of uranium bone cells with a special emphasis or the bystander effect at low dose.All the beam lines at the LPS nuclear microprobe are horizontal and under vacuum. A dedicated deflecting magnet was inserted in one of the two available beam lines of the facility. The ion beam is extracted to air using a 100 nm thick silicon nitride membrane, thin enough to induce negligible effects on the ions in terms of energy loss and spatial resolution. By this way, we believe that we minimize the experimental setup impact on the living cells easing the detection of low irradiation dose impact. The atmosphere around the samples is also important to guaranty low stressed cell culture conditions. A temperature, hygrometry and CO{sub 2} controlled atmosphere device will be implanted in the future. The irradiation microbeam is produced using a fused silica

  7. CD30 on extracellular vesicles from malignant Hodgkin cells supports damaging of CD30 ligand-expressing bystander cells with Brentuximab-Vedotin, in vitro.

    Science.gov (United States)

    Hansen, Hinrich P; Trad, Ahmad; Dams, Maria; Zigrino, Paola; Moss, Marcia; Tator, Maximilian; Schön, Gisela; Grenzi, Patricia C; Bachurski, Daniel; Aquino, Bruno; Dürkop, Horst; Reiners, Katrin S; von Bergwelt-Baildon, Michael; Hallek, Michael; Grötzinger, Joachim; Engert, Andreas; Paes Leme, Adriana F; Pogge von Strandmann, Elke

    2016-05-24

    The goal of targeted immunotherapy in cancer is to damage both malignant and tumor-supporting cells of the microenvironment but spare unaffected tissue. The malignant cells in classical Hodgkin lymphoma (cHL) selectively express CD30. They release this receptor on extracellular vesicles (EVs) for the tumor-supporting communication with CD30 ligand (CD30L)-positive bystander cells. Here, we investigated how CD30-positive EVs influence the efficacy of the CD30 antibody drug conjugate (ADC) Brentuximab Vedotin (SGN-35). The malignant cells and the EVs expressed the active sheddase ADAM10. ADAM10 cleaved and released the CD30 ectodomain (sCD30), causing a gradual depletion of SGN-35 binding sites on EVs and creating a soluble competitor of the ADC therapy. In a 3D semi-solid tumor microenvironment model, the EVs were retained in the matrix whereas sCD30 penetrated readily into the surrounding culture medium. This resulted in a lowered ratio of EV-associated CD30 (CD30EV) to sCD30 in the surrounding medium in comparison to non-embedded cultures. A low percentage of CD30EV was also detected in the plasma of cHL patients, supporting the clinical relevance of the model. The adherence of CD30EV but not sCD30 to CD30-/CD30L+ mast cells and eosinophils allowed the indirect binding of SGN-35. Moreover, SGN-35 damaged CD30-negative cells, provided they were loaded with CD30+ EVs.

  8. Bystanders Are the Key to Stopping Bullying

    Science.gov (United States)

    Padgett, Sharon; Notar, Charles E.

    2013-01-01

    Bullying is the dominance over another. Bullying occurs when there is an audience. Peer bystanders provide an audience 85% of instances of bullying. If you remove the audience bullying should stop. The article is a review of literature (2002-2013) on the role of bystanders; importance of bystanders; why bystanders behave as they do; resources to…

  9. Susceptibility to bystander DNA damage is influenced by replication and transcriptional activity.

    Science.gov (United States)

    Dickey, Jennifer S; Baird, Brandon J; Redon, Christophe E; Avdoshina, Valeriya; Palchik, Guillermo; Wu, Junfang; Kondratyev, Alexei; Bonner, William M; Martin, Olga A

    2012-11-01

    Direct cellular DNA damage may lead to genome destabilization in unexposed, bystander, cells sharing the same milieu with directly damaged cells by means of the bystander effect. One proposed mechanism involves double strand break (DSB) formation in S phase cells at sites of single strand lesions in the DNA of replication complexes, which has a more open structure compared with neighboring DNA. The DNA in transcription complexes also has a more open structure, and hence may be susceptible to bystander DSB formation from single strand lesions. To examine whether transcription predisposes non-replicating cells to bystander effect-induced DNA DSBs, we examined two types of primary cells that exhibit high levels of transcription in the absence of replication, rat neurons and human lymphocytes. We found that non-replicating bystander cells with high transcription rates exhibited substantial levels of DNA DSBs, as monitored by γ-H2AX foci formation. Additionally, as reported in proliferating cells, TGF-β and NO were found to mimic bystander effects in cell populations lacking DNA synthesis. These results indicate that cell vulnerability to bystander DSB damage may result from transcription as well as replication. The findings offer insights into which tissues may be vulnerable to bystander genomic destabilization in vivo.

  10. Tetherin restricts productive HIV-1 cell-to-cell transmission.

    Directory of Open Access Journals (Sweden)

    Nicoletta Casartelli

    Full Text Available The IFN-inducible antiviral protein tetherin (or BST-2/CD317/HM1.24 impairs release of mature HIV-1 particles from infected cells. HIV-1 Vpu antagonizes the effect of tetherin. The fate of virions trapped at the cell surface remains poorly understood. Here, we asked whether tetherin impairs HIV cell-to-cell transmission, a major means of viral spread. Tetherin-positive or -negative cells, infected with wild-type or DeltaVpu HIV, were used as donor cells and cocultivated with target lymphocytes. We show that tetherin inhibits productive cell-to-cell transmission of DeltaVpu to targets and impairs that of WT HIV. Tetherin accumulates with Gag at the contact zone between infected and target cells, but does not prevent the formation of virological synapses. In the presence of tetherin, viruses are then mostly transferred to targets as abnormally large patches. These viral aggregates do not efficiently promote infection after transfer, because they accumulate at the surface of target cells and are impaired in their fusion capacities. Tetherin, by imprinting virions in donor cells, is the first example of a surface restriction factor limiting viral cell-to-cell spread.

  11. Critical role of gap junction communication, calcium and nitric oxide signaling in bystander responses to focal photodynamic injury.

    Science.gov (United States)

    Calì, Bianca; Ceolin, Stefano; Ceriani, Federico; Bortolozzi, Mario; Agnellini, Andrielly H R; Zorzi, Veronica; Predonzani, Andrea; Bronte, Vincenzo; Molon, Barbara; Mammano, Fabio

    2015-04-30

    Ionizing and nonionizing radiation affect not only directly targeted cells but also surrounding "bystander" cells. The underlying mechanisms and therapeutic role of bystander responses remain incompletely defined. Here we show that photosentizer activation in a single cell triggers apoptosis in bystander cancer cells, which are electrically coupled by gap junction channels and support the propagation of a Ca2+ wave initiated in the irradiated cell. The latter also acts as source of nitric oxide (NO) that diffuses to bystander cells, in which NO levels are further increased by a mechanism compatible with Ca(2+)-dependent enzymatic production. We detected similar signals in tumors grown in dorsal skinfold chambers applied to live mice. Pharmacological blockade of connexin channels significantly reduced the extent of apoptosis in bystander cells, consistent with a critical role played by intercellular communication, Ca2+ and NO in the bystander effects triggered by photodynamic therapy.

  12. Involvement of MAPK proteins in bystander effects induced by chemicals and ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Asur, Rajalakshmi [Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Suite 1370, Detroit, MI 48202-3917 (United States); Balasubramaniam, Mamtha [Research Institute - Biostatistics, William Beaumont Hospital, 3911 W. Thirteen Mile Road, Royal Oak, MI 48073 (United States); Marples, Brian [Department of Radiation Oncology, William Beaumont Hospital, 3811 W. Thirteen Mile Road, Royal Oak, MI 48073 (United States); Thomas, Robert A. [Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Suite 1370, Detroit, MI 48202-3917 (United States); Tucker, James D., E-mail: jtucker@biology.biosci.wayne.edu [Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Suite 1370, Detroit, MI 48202-3917 (United States)

    2010-04-01

    Many studies have examined bystander effects induced by ionizing radiation, however few have evaluated the ability of chemicals to induce similar effects. We previously reported the ability of two chemicals, mitomycin C (MMC) and phleomycin (PHL) to induce bystander effects in normal human lymphoblastoid cell lines. The focus of the current study was to determine the involvement of the MAPK proteins in bystander effects induced by physical and chemical DNA damaging agents and to evaluate the effects of MAPK inhibition on bystander-induced caspase 3/7 activation. The phosphorylation levels of the MAPK proteins ERK1/2, JNK, and p38, were measured from 1 to 24 h following direct or bystander exposure to MMC, PHL or radiation. We observed transient phosphorylation, at early time points, of all 3 proteins in bystander cells. We also evaluated the effect of MAPK inhibition on bystander-induced caspase 3/7 activity to determine the role of MAPK proteins in bystander-induced apoptosis. We observed bystander-induced activation of caspase 3/7 in bystander cells. Inhibition of MAPK proteins resulted in a decrease in caspase 3/7 activity at the early time points, and the caspase activity increased (in the case of ERK inhibition) or returned to basal levels (in the case of JNK or p38 inhibition) between 12 and 24 h. PHL is considered to be a radiomimetic agent, however in the present study PHL behaved more like a chemical and not like radiation in terms of MAPK phosphorylation. These results point to the involvement of MAPK proteins in the bystander effect induced by radiation and chemicals and provide additional evidence that this response is not limited to radiation but is a generalized stress response in cells.

  13. Novel mathematical models for cell-mediated cytotoxicity assays without applying enzyme kinetics but with combinations and probability: bystanders in bulk effector cells influence results of cell-mediated cytotoxicity assays.

    Science.gov (United States)

    Takayanagi, Toshiaki

    2011-07-01

    Cell-mediated cytotoxicity assays are widely implemented to evaluate cell-mediated cytotoxic activity, and some assays are analyzed using the analogy of enzyme kinetics. In the analogy, the effector cell is regarded as the enzyme, the target cell as the substrate, the effector cell-target cell conjugate as the enzyme-substrate complex and the dead target cell as the product. However, the assumptions analogous to those of enzyme kinetics are not always true in cell-mediated cytotoxicity assays, and the parameter analogous to the Michaelis-Menten constant is not constant but is dependent on the number of effector cells. Therefore I present novel mathematical models for cell-mediated cytotoxicity assays without applying enzyme kinetics. I instead use combinations and probability, because analysis of cell-mediated cytotoxicity assays by applying enzyme kinetics seems controversial. With my original models, I demonstrate simulations of the data in previously published papers. The results are exhibited in the same forms as the corresponding data. Comparing the simulation results with the published data, the results seem to agree well with the data. From simulations of cytotoxic assays with bulk effector cells, it appears that bystanders in bulk effector cells increase both the cytotoxic activity and the motility of effector cells.

  14. A role for bioelectric effects in the induction of bystander signals by ionizing radiation?

    Science.gov (United States)

    Mothersill, C; Moran, G; McNeill, F; Gow, M D; Denbeigh, J; Prestwich, W; Seymour, C B

    2007-04-03

    The induction of "bystander effects" i.e. effects in cells which have not received an ionizing radiation track, is now accepted but the mechanisms are not completely clear. Bystander effects following high and low LET radiation exposure are accepted but mechanisms are still not understood. There is some evidence for a physical component to the signal. This paper tests the hypothesis that bioelectric or biomagnetic phenomena are involved. Human immortalized skin keratinocytes and primary explants of mouse bladder and fish skin, were exposed directly to ionizing radiation or treated in a variety of bystander protocols. Exposure of cells was conducted by shielding one group of flasks using lead, to reduce the dose below the threshold of 2mGy (60)Cobalt gamma rays established for the bystander effect. The endpoint for the bystander effect in the reporter system used was reduction in cloning efficiency (RCE). The magnitude of the RCE was similar in shielded and unshielded flasks. When cells were placed in a Faraday cage the magnitude of the RCE was less but not eliminated. The results suggest that liquid media or cell-cell contact transmission of bystander factors may be only part of the bystander mechanism. Bioelectric or bio magnetic fields may have a role to play. To test this further, cells were placed in a Magnetic Resonance Imaging (MRI) machine for 10 min using a typical head scan protocol. This treatment also induced a bystander response. Apart from the obvious clinical relevance, the MRI results further suggest that bystander effects may be produced by non-ionizing exposures. It is concluded that bioelectric or magnetic effects may be involved in producing bystander signaling cascades commonly seen following ionizing radiation exposure.

  15. Bystander effect induced by UV radiation; why should we be interested?

    Science.gov (United States)

    Widel, Maria

    2012-11-14

    The bystander effect, whose essence is an interaction of cells directly subjected to radiation with adjacent non-subjected cells, via molecular signals, is an important component of ionizing radiation action. However, knowledge of the bystander effect in the case of ultraviolet (UV) radiation is quite limited. Reactive oxygen and nitrogen species generated by UV in exposed cells induce bystander effects in non-exposed cells, such as reduction in clonogenic cell survival and delayed cell death, oxidative DNA damage and gene mutations, induction of micronuclei, lipid peroxidation and apoptosis. Although the bystander effect after UV radiation has been recognized in cell culture systems, its occurrence in vivo has not been studied. However, solar UV radiation, which is the main source of UV in the environment, may induce in human dermal tissue an inflammatory response and immune suppression, events which can be considered as bystander effects of UV radiation. The oxidative damage to DNA, genomic instability and the inflammatory response may lead to carcinogenesis. UV radiation is considered one of the important etiologic factors for skin cancers, basal- and squamous-cell carcinomas and malignant melanoma. Based on the mechanisms of actions it seems that the UV-induced bystander effect can have some impact on skin damage (carcinogenesis?), and probably on cells of other tissues. The paper reviews the existing data about the UV-induced bystander effect and discusses a possible implication of this phenomenon for health risk. 

  16. Caffeine Markedly Enhanced Radiation-Induced Bystander Effects

    Institute of Scientific and Technical Information of China (English)

    JIANG Erkang; WU Lijun

    2009-01-01

    A bstract In this paper it is shown that incubation with 2 mM caffeine enhanced significantly the MN (micronucleus) formation in both the 1 cGy a-particle irradiated and non-irradiated by- stander regions. Moreover, caffeine treatment made the non-irradiated bystander cells more sensi- tive to damage signals. Treated by c-PTIO(2-(4-carboxy-phenyl)-4,4,5,5-tetramethyl-imidazoline- 1-oxyl-3-oxide), a nitric oxide (NO) scavenger, the MN frequencies were effectively inhibited, showing that nitric oxide might be very important in mediating the enhanced damage. These results indicated that caffeine enhanced the low dose a-particle radiation-induced damage in ir- radiated and non-irradiated bystander regions, and therefore it is important to investigate the relationship between the radiosensitizer and radiation-induced bystander effects (RIBE).

  17. Lack of Bystander Effects From High LET Radiation For Early Cytogenetic Endpoints.

    Energy Technology Data Exchange (ETDEWEB)

    Groesser, Torsten; Cooper, Brian; Rydberg, Bjorn

    2008-05-07

    The aim of this work was to study radiation-induced bystander effects for early cytogenetic end points in various cell lines using the medium transfer technique after exposure to high- and low-LET radiation. Cells were exposed to 20 MeV/ nucleon nitrogen ions, 968 MeV/nucleon iron ions, or 575 MeV/nucleon iron ions followed by transfer of the conditioned medium from the irradiated cells to unirradiated test cells. The effects studied included DNA double-strand break induction, {gamma}-H2AX focus formation, induction of chromatid breaks in prematurely condensed chromosomes, and micronucleus formation using DNA repair-proficient and -deficient hamster and human cell lines (xrs6, V79, SW48, MO59K and MO59J). Cell survival was also measured in SW48 bystander cells using X rays. Although it was occasionally possible to detect an increase in chromatid break levels using nitrogen ions and to see a higher number of {gamma}-H2AX foci using nitrogen and iron ions in xrs6 bystander cells in single experiments, the results were not reproducible. After we pooled all the data, we could not verify a significant bystander effect for any of these end points. Also, we did not detect a significant bystander effect for DSB induction or micronucleus formation in these cell lines or for clonogenic survival in SW48 cells. The data suggest that DNA damage and cytogenetic changes are not induced in bystander cells. In contrast, data in the literature show pronounced bystander effects in a variety of cell lines, including clonogenic survival in SW48 cells and induction of chromatid breaks and micronuclei in hamster cells. To reconcile these conflicting data, it is possible that the epigenetic status of the specific cell line or the precise culture conditions and medium supplements, such as serum, may be critical for inducing bystander effects.

  18. Moral Disengagement Among Bystanders to School Bullying

    DEFF Research Database (Denmark)

    Obermann, Marie-Louise

    2011-01-01

    This study examined the use of moral disengagement among children indirectly involved in bullying (bystanders). A sample of Danish adolescents (N = 660, M age 12.6 years) were divided into four groups depending on their bystander status: (a) outsiders, who did not experience bullying among...... their peers; (b) defenders, who were likely to help the victims in bullying episodes; (c) guilty bystanders, who did nothing to help bullied peers but felt guilty about it; and (d) unconcerned bystanders, who witnessed peers being bullied, without feeling responsible. Results indicated that, besides from...... active personal involvement in bullying others, being an unconcerned bystander to bullying also associates with moral disengagement. Unconcerned bystanders had significantly higher moral disengagement than guilty bystanders and defenders. Outsiders also showed significant higher disengagement than...

  19. Polysaccharide-specific memory B cells generated by conjugate vaccines in humans conform to the CD27+IgG+ isotype-switched memory B Cell phenotype and require contact-dependent signals from bystander T cells activated by bacterial proteins to differentiate into plasma cells.

    Science.gov (United States)

    Clarke, Edward T; Williams, Neil A; Findlow, Jamie; Borrow, Ray; Heyderman, Robert S; Finn, Adam

    2013-12-15

    The polysaccharides (PS) surrounding encapsulated bacteria are generally unable to activate T cells and hence do not induce B cell memory (BMEM). PS conjugate vaccines recruit CD4(+) T cells via a carrier protein, such as tetanus toxoid (TT), resulting in the induction of PS-specific BMEM. However, the requirement for T cells in the subsequent activation of the BMEM at the time of bacterial encounter is poorly understood, despite having critical implications for protection. We demonstrate that the PS-specific BMEM induced in humans by a meningococcal serogroup C PS (Men C)-TT conjugate vaccine conform to the isotype-switched (IgG(+)CD27(+)) rather than the IgM memory (IgM(+)CD27(+)) phenotype. Both Men C and TT-specific BMEM require CD4(+) T cells to differentiate into plasma cells. However, noncognate bystander T cells provide such signals to PS-specific BMEM with comparable effect to the cognate T cells available to TT-specific BMEM. The interaction between the two populations is contact-dependent and is mediated in part through CD40. Meningococci drive the differentiation of the Men C-specific BMEM through the activation of bystander T cells by bacterial proteins, although these signals are enhanced by T cell-independent innate signals. An effect of the TT-specific T cells activated by the vaccine on unrelated BMEM in vivo is also demonstrated. These data highlight that any protection conferred by PS-specific BMEM at the time of bacterial encounter will depend on the effectiveness with which bacterial proteins are able to activate bystander T cells. Priming for T cell memory against bacterial proteins through their inclusion in vaccine preparations must continue to be pursued.

  20. Effects of Low-Dose Alpha-Particle Irradiation in Human Cells: The Role of Induced Genes and the Bystander Effect. Final Technical Report (9/15/1998-5/31/2005)

    Energy Technology Data Exchange (ETDEWEB)

    Little, John B.

    2013-09-17

    This grant was designed to examine the cellular and molecular mechanisms for the bystander effect of radiation (initially described in this laboratory) whereby damage signals are passed from irradiated to non-irradiated cells in a population. These signals induce genetic effects including DNA damage, mutations and chromosomal aberrations in the nonirradiated cells. Experiments were carried out in cultured mammalian cells, primarily human diploid cells, irradiated with alpha particles. This research resulted in 17 publications in the refereed literature and is described in the Progress Report where it is keyed to the publication list. This project was initiated at the Harvard School of Public Health (HSPH) and continued in collaboration with students/fellows at Colorado State University (CSU) and the New Jersey Medical School (NJMS).

  1. Fate restriction and multipotency in retinal stem cells.

    Science.gov (United States)

    Centanin, Lázaro; Hoeckendorf, Burkhard; Wittbrodt, Joachim

    2011-12-02

    Stem cells have the capacity to both self-renew and generate postmitotic cells. Long-term tracking of individual clones in their natural environment constitutes the ultimate way to validate postembryonic stem cells. We identify retinal stem cells (RSCs) using the spatiotemporal organization of the fish retina and follow the complete offspring of a single cell during the postnatal life. RSCs generate two tissues of the adult fish retina, the neural retina (NR) and the retinal-pigmented epithelium (RPE). Despite their common embryonic origin and tight coordination during continuous organ growth, we prove that NR and RPE are maintained by dedicated RSCs that contribute in a fate-restricted manner to either one or the other tissue. We show that in the NR, RSCs are multipotent and generate all neuron types and glia. The clonal origin of these different cell types from a multipotent NSC has far-reaching implications for cell type and tissue homeostasis.

  2. The key role of miR-21-regulated SOD2 in the medium-mediated bystander responses in human fibroblasts induced by α-irradiated keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Wenqian; Yin, Xiaoming; Wang, Longxiao; Wang, Jingdong; Zhu, Wei; Cao, Jianping [School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China); Yang, Hongying, E-mail: yanghongying@suda.edu.cn [School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China); Institute of Radiotherapy & Oncology, Soochow University (China)

    2015-10-15

    Highlights: • After co-culture with α-irradiated HaCaT cells, WS1 cells displayed oxidative stress and DNA damage. • Increased miR-21 expression in bystander cells was critical to the occurrence of RIBEs. • SOD2 of bystander cells played an important role in bystander responses. • miR-21 mediated bystander effects through its regulation on SOD2. - Abstract: Radiation-induced bystander effect (RIBE) is well accepted in the radiation research field by now, but the underlying molecular mechanisms for better understanding this phenomenon caused by intercellular communication and intracellular signal transduction are still incomplete. Although our previous study has demonstrated an important role of miR-21 of unirradiated bystander cells in RIBEs, the direct evidence for the hypothesis that RIBE is epigenetically regulated is still limited and how miR-21 mediates RIBEs is unknown. Reactive oxygen species (ROS) have been demonstrated to be involved in RIBEs, however, the roles of anti-oxidative stress system of cells in RIBEs are unclear. Using transwell insert co-culture system, we investigated medium-mediated bystander responses in WS1 human fibroblasts after co-culture with HaCaT keratinocytes traversed by α-particles. Results showed that the ROS levels in unirradiated bystander WS1 cells were significantly elevated after 30 min of co-culture, and 53BP1 foci, a surrogate marker of DNA damage, were obviously induced after 3 h of co-culture. This indicates the occurrence of oxidative stress and DNA damage in bystander WS1 cells after co-culture with irradiated keratinocytes. Furthermore, the expression of miR-21 was increased in bystander WS1 cells, downregulation of miR-21 eliminated the bystander responses, overexpression of miR-21 alone could induce bystander-like oxidative stress and DNA damage in WS1 cells. These data indicate an important mediating role of miR-21 in RIBEs. In addition, MnSOD or SOD2 in WS1 cells was involved in the bystander effects

  3. Reciprocal bystander effect between α-irradiated macrophage and hepatocyte is mediated by cAMP through a membrane signaling pathway.

    Science.gov (United States)

    He, Mingyuan; Dong, Chen; Xie, Yuexia; Li, Jitao; Yuan, Dexiao; Bai, Yang; Shao, Chunlin

    2014-01-01

    Irradiated cells can induce biological effects on vicinal non-irradiated bystander cells, meanwhile the bystander cells may rescue the irradiated cells through a feedback signal stress. To elucidate the nature of this reciprocal effect, we examined the interaction between α-irradiated human macrophage cells U937 and its bystander HL-7702 hepatocyte cells using a cell co-culture system. Results showed that after 6h of cell co-culture, mitochondria depolarization corresponding to apoptosis was significantly induced in the HL-7702 cells, but the formation of micronuclei in the irradiated U937 cells was markedly decreased compared to that without cell co-culture treatment. This reciprocal effect was not observed when the cell membrane signaling pathway was blocked by filipin that inhibited cAMP transmission from bystander cells to irradiated cells. After treatment of cells with exogenous cAMP, forskolin (an activator of cAMP) or KH-7 (an inhibitor of cAMP), respectively, it was confirmed that cAMP communication from bystander cells to targeted cells could mitigate radiation damage in U739 cells, and this cAMP insufficiency in the bystander cells contributed to the enhancement of bystander apoptosis. Moreover, the bystander apoptosis in HL-7702 cells was aggravated by cAMP inhibition but it could not be evoked when p53 of HL-7702 cells was knocked down no matter of forskolin and KH-7 treatment. In conclusion, this study disclosed that cAMP could be released from bystander HL-7702 cells and compensated to α-irradiated U937 cells through a membrane signaling pathway and this cAMP communication played a profound role in regulating the reciprocal bystander effects.

  4. Critical role of gap junction communication, calcium and nitric oxide signaling in bystander responses to focal photodynamic injury

    OpenAIRE

    Calì, Bianca; Ceolin, Stefano; Ceriani, Federico; Bortolozzi, Mario; Agnellini, Andrielly H.R.; Zorzi, Veronica; Predonzani, Andrea; Bronte, Vincenzo; Molon, Barbara; Mammano, Fabio

    2015-01-01

    Ionizing and nonionizing radiation affect not only directly targeted cells but also surrounding “bystander” cells. The underlying mechanisms and therapeutic role of bystander responses remain incompletely defined. Here we show that photosentizer activation in a single cell triggers apoptosis in bystander cancer cells, which are electrically coupled by gap junction channels and support the propagation of a Ca2+ wave initiated in the irradiated cell. The latter also acts as source of nitric oxi...

  5. Critical role of gap junction communication, calcium and nitric oxide signaling in bystander responses to focal photodynamic injury

    OpenAIRE

    Cali, B.; Ceolin, S.; Ceriani, F.; Bortolozzi, M.; Agnellini, A.H.R.; Zorzi, V.; Predonzani, A.; BRONTE, V; Molon, B.; Mammano, F.

    2015-01-01

    Ionizing and nonionizing radiation affect not only directly targeted cells but also\\ud surrounding “bystander” cells. The underlying mechanisms and therapeutic role of\\ud bystander responses remain incompletely deined. Here we show that photosentizer\\ud activation in a single cell triggers apoptosis in bystander cancer cells, which are\\ud electrically coupled by gap junction channels and support the propagation of a Ca2+\\ud wave initiated in the irradiated cell. The latter also acts as source...

  6. Restrictive versus liberal transfusion strategy for red blood cell transfusion

    DEFF Research Database (Denmark)

    Holst, Lars B; Petersen, Marie W; Haase, Nicolai;

    2015-01-01

    OBJECTIVE: To compare the benefit and harm of restrictive versus liberal transfusion strategies to guide red blood cell transfusions. DESIGN: Systematic review with meta-analyses and trial sequential analyses of randomised clinical trials. DATA SOURCES: Cochrane central register of controlled...... trials, SilverPlatter Medline (1950 to date), SilverPlatter Embase (1980 to date), and Science Citation Index Expanded (1900 to present). Reference lists of identified trials and other systematic reviews were assessed, and authors and experts in transfusion were contacted to identify additional trials....... TRIAL SELECTION: Published and unpublished randomised clinical trials that evaluated a restrictive compared with a liberal transfusion strategy in adults or children, irrespective of language, blinding procedure, publication status, or sample size. DATA EXTRACTION: Two authors independently screened...

  7. Moral Disengagement among Bystanders to School Bullying

    Science.gov (United States)

    Obermann, Marie-Louise

    2011-01-01

    This study examined the use of moral disengagement among children indirectly involved in bullying (bystanders). A sample of Danish adolescents (N = 660, M age 12.6 years) were divided into four groups depending on their bystander status: (a) outsiders, who did not experience bullying among their peers; (b) defenders, who were likely to help the…

  8. Cell entry of lymphocytic choriomeningitis virus is restricted in myotubes.

    Science.gov (United States)

    Iwasaki, Masaharu; Urata, Shuzo; Cho, Yoshitake; Ngo, Nhi; de la Torre, Juan C

    2014-06-01

    In mice persistently infected since birth with the prototypic arenavirus lymphocytic choriomeningitis viurs, viral antigen and RNA are readily detected in most organs and cell types but remarkably absent in skeletal muscle. Here we report that mouse C2C12 myoblasts that are readily infected by LCMV, become highly refractory to LCMV infection upon their differentiation into myotubes. Myotube's resistance to LCMV was not due to an intracellular restriction of virus replication but rather an impaired cell entry mediated by the LCMV surface glycoprotein. Our findings provide an explanation for the observation that in LCMV carrier mice myotubes, which are constantly exposed to blood-containing virus, remain free of viral antigen and RNA despite myotubes express high levels of the LCMV receptor alpha dystroglycan and do not pose an intracellular blockade to LCMV multiplication.

  9. Vincristine-induced bystander effect in human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Testi, Serena; Azzarà, Alessia; Giovannini, Caterina; Lombardi, Sara [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Piaggi, Simona [Dipartimento di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, Pisa University, Via Savi 10, 56126 Pisa (Italy); Facioni, Maria Sole [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Scarpato, Roberto, E-mail: roberto.scarpato@unipi.it [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Research Center of Nutraceuticals and Food for Health, University of Pisa, Pisa (Italy)

    2016-07-15

    Highlights: • We studied whether or not vincristine induced a bystander response in human lymphocytes. • Vincristine significantly increased MN frequencies in mononucleated recipient cells. • ROS or soluble proteins (IL-32 and TGF-β) may account for the observed response. - Abstract: Bystander effect is a known radiobiological effect, widely described using ionizing radiations and which, more recently, has also been related to chemical mutagens. In this study, we aimed to assess whether or not a bystander response can be induced in cultured human peripheral lymphocytes by vincristine, a chemotherapeutic mutagen acting as spindle poison, and by mitomycin-C, an alkylating agent already known to induce this response in human lymphoblastoid cells. Designing a modified ad hoc protocol for the cytokinesis blocked micronucleus (MN) assay, we detected the presence of a dose-dependent bystander response in untreated cultures receiving the conditioned medium (CM) from mitomycin-C (MMC) or vincristine (VCR) treated cultures. In the case of MMC, MN frequencies, expressed as micronucleated binucleates, were: 13.5 ± 1.41 at 6 μM, 22 ± 2.12 at 12 μM or 28.25 ± 5.13 at 15 μM vs. a control value of 4.75 ± 1.59. MN levels for VCR, expressed as micronucleated mononucleates were: 2.75 ± 0.88 at 0.0 μM, 27.25 ± 2.30 at 0.4 μM, 46.25 ± 1.94 at 0.8 μM, 98.25 ± 7.25 at 1.6 μM. To verify that no mutagen residual was transferred to recipient cultures together with the CM, we evaluated MN levels in cultures receiving the medium immediately after three washings following the chemical treatment (unconditioned medium). We further confirmed these results using a cell-mixing approach where untreated lymphocytes were co-cultured with donor cells treated with an effect-inducing dose of MMC or VCR. A distinct production pattern of both reactive oxygen species and soluble mediator proteins by treated cells may account for the differences observed in the manifestation of the

  10. Bystander Effects During Synchrotron Imaging Procedures?

    Science.gov (United States)

    Schültke, Elisabeth; Bewer, Brian; Wysokinski, Tomasz; Chapman, Dean; Nikkhah, Guido

    2010-07-01

    Using monochromatic beam and synchrotron phase-contrast technique at the biomedical beamline of the Italian synchrotron facility Elettra (SYRMEP), we have shown in a small animal model of malignant brain tumor that it is possible to obtain high-resolution images of very small tumors when they have developed from implanted tumor cells loaded with colloidal gold nanoparticles (GNP). All previous experiments were conducted in post-mortem samples. We have now designed a cell culture experiment to investigate the effects of synchrotron radiation with an energy and dose profile similar to that expected in our first in vivo imaging studies according to the protocol developed at SYRMEP. Materials and Methods: Culture flasks containing either gold-loaded or naïve C6 glioma cells were exposed to a dose of 0.5 Gy at 24 keV. The irradiated medium was aspirated and replaced with fresh growth medium. Twenty-four hours later this non-irradiated medium exposed to irradiated cells was aspirated, then added to non-irradiated C6 cells in order to investigate whether bystander effects are seen under the conditions of our image acquisition protocol. The irradiated medium was added to a number of other non-irradiated cell cultures. Cell counts were followed until 72 hrs after irradiation. Western blots were conducted with H2AX antibodies. This experiment was one of the first biomedical experiments conducted at BMIT, the new biomedical imaging and therapy beamline of the Canadian Light Source. Results: No significant differences in proliferation were seen between cells that were directly irradiated, exposed to irradiated medium or exposed to the non-irradiated 24-hr-medium from the irradiated cells. However, there was a tendency towards a higher number of double strand breaks in previously irradiated cells when they were exposed to non-irradiated medium that had been in contact with irradiated cells for 24 hrs.

  11. Caspase-3-independent pathways proceeding in bystander effect of HSV-tk/GCV system

    Science.gov (United States)

    Lin, Juqiang; Ma, Yan; Zeng, Shaoqun; Zhang, Zhihong

    2008-02-01

    HSV-tk/GCV system, which is the virus-directed enzyme/prodrug therapy of herpes simplex virus (HSV) thymidine kinase (tk) gene / the anti-viral reagent ganciclovir (GCV), is one of the promising approaches in the rapidly growing area of gene therapy. As gene therapy of cancer such as suicide gene therapy has entered the clinic, another therapy effect which is called 'bystander effect' was reported. Bystander effect can lead to killing of non-transduced tumor cells in the immediate vicinity of GCV-treated HSV-TK-positive cells. Now the magnitude of 'bystander effect' is an essential factor for this anti-tumor approach in vivo. However, the mechanism which HSV-tk/ACV brings "bystander effect" is poorly understood. In this study, we monitor the activation of caspase-3 in HSV-tk/GCV system by a FRET probe CD3, a FRET-based indicator for activity of caspase3, which is composed of an enhanced cyan fluorescent protein, a caspase-sensitive linker, and a red fluorescent protein from Discosoma with efficient maturation property. Through application of CD3 we have visualized the activation of caspase-3 in tk gene positive human adenoid cystic carcinoma (ACC-M) cells but not in bystander effect of HSV-tk/GCV system induced by GCV. This finding provides needed information for understanding the mechanisms by which suicide gene approaches actually kill cancer cells, and may prove to be helpful for the clinical treatment of cancers.

  12. Radiation and chemotherapy bystander effects induce early genomic instability events: telomere shortening and bridge formation coupled with mitochondrial dysfunction.

    LENUS (Irish Health Repository)

    Gorman, Sheeona

    2012-02-01

    The bridge breakage fusion cycle is a chromosomal instability mechanism responsible for genomic changes. Radiation bystander effects induce genomic instability; however, the mechanism driving this instability is unknown. We examined if radiation and chemotherapy bystander effects induce early genomic instability events such as telomere shortening and bridge formation using a human colon cancer explant model. We assessed telomere lengths, bridge formations, mitochondrial membrane potential and levels of reactive oxygen species in bystander cells exposed to medium from irradiated and chemotherapy-treated explant tissues. Bystander cells exposed to media from 2Gy, 5Gy, FOLFOX treated tumor and matching normal tissue showed a significant reduction in telomere lengths (all p values <0.018) and an increase in bridge formations (all p values <0.017) compared to bystander cells treated with media from unirradiated tissue (0Gy) at 24h. There was no significant difference between 2Gy and 5Gy treatments, or between effects elicited by tumor versus matched normal tissue. Bystander cells exposed to media from 2Gy irradiated tumor tissue showed significant depolarisation of the mitochondrial membrane potential (p=0.012) and an increase in reactive oxygen species levels. We also used bystander cells overexpressing a mitochondrial antioxidant manganese superoxide dismutase (MnSOD) to examine if this antioxidant could rescue the mitochondrial changes and subsequently influence nuclear instability events. In MnSOD cells, ROS levels were reduced (p=0.02) and mitochondrial membrane potential increased (p=0.04). These events were coupled with a decrease in percentage of cells with anaphase bridges and a decrease in the number of cells undergoing telomere length shortening (p values 0.01 and 0.028 respectively). We demonstrate that radiation and chemotherapy bystander responses induce early genomic instability coupled with defects in mitochondrial function. Restoring mitochondrial

  13. Radiation and chemotherapy bystander effects induce early genomic instability events: Telomere shortening and bridge formation coupled with mitochondrial dysfunction

    Energy Technology Data Exchange (ETDEWEB)

    Gorman, Sheeona; Tosetto, Miriam [Centre for Colorectal Disease, St. Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); Lyng, Fiona; Howe, Orla [Radiation and Environmental Science Centre, Dublin Institute of Technology and St. Luke' s Hospital, Dublin (Ireland); Sheahan, Kieran; O' Donoghue, Diarmuid; Hyland, John; Mulcahy, Hugh [Centre for Colorectal Disease, St. Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); O' Sullivan, Jacintha, E-mail: jacintha.osullivan@ucd.ie [Centre for Colorectal Disease, St. Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland)

    2009-10-02

    The bridge breakage fusion cycle is a chromosomal instability mechanism responsible for genomic changes. Radiation bystander effects induce genomic instability; however, the mechanism driving this instability is unknown. We examined if radiation and chemotherapy bystander effects induce early genomic instability events such as telomere shortening and bridge formation using a human colon cancer explant model. We assessed telomere lengths, bridge formations, mitochondrial membrane potential and levels of reactive oxygen species in bystander cells exposed to medium from irradiated and chemotherapy-treated explant tissues. Bystander cells exposed to media from 2 Gy, 5 Gy, FOLFOX treated tumor and matching normal tissue showed a significant reduction in telomere lengths (all p values <0.018) and an increase in bridge formations (all p values <0.017) compared to bystander cells treated with media from unirradiated tissue (0 Gy) at 24 h. There was no significant difference between 2 Gy and 5 Gy treatments, or between effects elicited by tumor versus matched normal tissue. Bystander cells exposed to media from 2 Gy irradiated tumor tissue showed significant depolarisation of the mitochondrial membrane potential (p = 0.012) and an increase in reactive oxygen species levels. We also used bystander cells overexpressing a mitochondrial antioxidant manganese superoxide dismutase (MnSOD) to examine if this antioxidant could rescue the mitochondrial changes and subsequently influence nuclear instability events. In MnSOD cells, ROS levels were reduced (p = 0.02) and mitochondrial membrane potential increased (p = 0.04). These events were coupled with a decrease in percentage of cells with anaphase bridges and a decrease in the number of cells undergoing telomere length shortening (p values 0.01 and 0.028 respectively). We demonstrate that radiation and chemotherapy bystander responses induce early genomic instability coupled with defects in mitochondrial function. Restoring

  14. Reciprocal bystander effect between α-irradiated macrophage and hepatocyte is mediated by cAMP through a membrane signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    He, Mingyuan [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China); Department of Radiation Oncology, China–Japan Union Hospital of Jilin University, Changchun 130033 (China); Dong, Chen; Xie, Yuexia; Li, Jitao; Yuan, Dexiao; Bai, Yang [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China); Shao, Chunlin, E-mail: clshao@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China)

    2014-05-15

    Highlights: • α-Irradiation induced reciprocal effects between macrophage and hepatocyte cells. • cAMP played a protective role in regulating the reverse bystander effect. • cAMP communication contributed to the reciprocal effects via membrane signaling. • p53 was required for cAMP-regulated bystander effect in the recipient cells. - Abstract: Irradiated cells can induce biological effects on vicinal non-irradiated bystander cells, meanwhile the bystander cells may rescue the irradiated cells through a feedback signal stress. To elucidate the nature of this reciprocal effect, we examined the interaction between α-irradiated human macrophage cells U937 and its bystander HL-7702 hepatocyte cells using a cell co-culture system. Results showed that after 6 h of cell co-culture, mitochondria depolarization corresponding to apoptosis was significantly induced in the HL-7702 cells, but the formation of micronuclei in the irradiated U937 cells was markedly decreased compared to that without cell co-culture treatment. This reciprocal effect was not observed when the cell membrane signaling pathway was blocked by filipin that inhibited cAMP transmission from bystander cells to irradiated cells. After treatment of cells with exogenous cAMP, forskolin (an activator of cAMP) or KH-7 (an inhibitor of cAMP), respectively, it was confirmed that cAMP communication from bystander cells to targeted cells could mitigate radiation damage in U739 cells, and this cAMP insufficiency in the bystander cells contributed to the enhancement of bystander apoptosis. Moreover, the bystander apoptosis in HL-7702 cells was aggravated by cAMP inhibition but it could not be evoked when p53 of HL-7702 cells was knocked down no matter of forskolin and KH-7 treatment. In conclusion, this study disclosed that cAMP could be released from bystander HL-7702 cells and compensated to α-irradiated U937 cells through a membrane signaling pathway and this cAMP communication played a profound role in

  15. Fv-1 locus restriction of mouse retroviruses in glucocorticoid-treated cells

    Energy Technology Data Exchange (ETDEWEB)

    Tennant, R.W.; Jones, S.C.; Otten, J.A.; Yang, W.K.; Brown, A.

    1978-08-01

    Treatment of mouse embryo cells with hydrocortisone (10/sup -6/M) or dexamethasone (10/sup -4/ to 10/sup -6/M) increases virus synthesis whether the cells are permissive or restrictive at the Fv-1 locus. However, the number of cells infected was not increased in either permissive or restrictive cells by treatment with either glucocorticoid, and the two-hit titration pattern in restrictive cells remained unaltered. Therefore, the enhancement of virus replication by the glucocorticoids is independent of Fv-1 restriction and appears to occur after the Fv-1 locus-sensitive step in virus synthesis.

  16. Restriction of human adenovirus replication in Chinese hamster cell lines and their hybrids with human cells.

    Science.gov (United States)

    Radna, R L; Foellmer, B; Feldman, L A; Francke, U; Ozer, H L

    1987-11-01

    We have found that the replication of human adenovirus (Ad2) is restricted in multiple Chinese hamster cell lines including CHO and V79. The major site of restriction involves differential accumulation of late viral proteins as demonstrated by immunofluorescence assay and polyacrylamide gel electrophoresis with and without prior immunoprecipitation. Synthesis of fiber and penton base are markedly reduced, whereas others, such as the 100K polypeptide, are synthesized efficiently. This pattern of restriction is similar to that previously reported for Ad2 infection of several monkey cell lines; however, the restriction is more marked in the Chinese hamster cell lines. The restriction is most likely due to a deficient cellular function since stable cell hybrids between V79 or CHO and human cells are permissive for virus replication. By analysis of a series of hybrids with reduced numbers of human chromosomes, fiber synthesis was correlated with the presence of the short arm of human chromosome 3. More hybrids showed restoration of fiber synthesis than production of progeny virus, suggesting that more than one unlinked function is required for the latter.

  17. Development of a mathematical model to study the radiation-induced bystander effect

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein, E-mail: spm@cdtn.b, E-mail: amsantos@cdtn.b, E-mail: seg@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nunes, Maria Eugenia S., E-mail: mariaeugenia@iceb.ufop.b [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

    2011-07-01

    Living organisms are composed of millions of cells that together perform tasks of great complexity. Although every cell has an internal structure that obeys the laws of chemistry and biochemistry, it is the interactions between cells that generate a range of different phenomena. Until the 1990s it was believed that the DNA was the single molecule affected by radiation, the so-called theory of the single target. But some observations began to challenge this theory; in 1992 the bystander effect was described by Nagasawa and Little. This effect is responsible for a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. Understanding the bystander effect may have important consequences for therapy and studies of low-dose risk. In this work, we have developed a computational model to study the bystander effect. This computational model is a two-dimensional cellular automata, consisting of two overlapping networks, where the first represents the cell culture, and the second one, the medium in which cells are embedded. The computational model allows the establishment of curves to describe the behavior of the effect for different levels of signals released in the irradiated medium by the irradiated cells or by the bystander cells when a second order effect is considered. The percentage of cell survival obtained from the mathematical model showed to be in good agreement with experimental data available in the literature. (author)

  18. 放线菌素D对仓鼠成纤维细胞V79靶细胞和旁观者细胞活力和染色体畸变的影响%Effect of actinomycin D on cell viability and chromosome aberration in hamster fibroblast V79 target and bystander cells

    Institute of Scientific and Technical Information of China (English)

    靳翠红; 巫生文; 逯晓波; 刘秋芳; 蔡原; 肖云

    2012-01-01

    目的:观察放线菌素D (actinomycinD,ACTD)对中国仓鼠成纤维细胞V79靶细胞和旁观者细胞的细胞活力和染色体畸变的影响,以确定ACTD能否诱导旁观者效应的发生.方法:用不同剂量ACTD(0、0.25、0.5、1.0、2.0、4.0和8.0 mg/L处理V79靶细胞1h,并选择其中4 mg/L ACTD作用1h开始计时,分别在第4、8、12和24h时取靶细胞去细胞培养液(conditioned medium,CM),培养正常细胞24h后,进行旁观者效应的观察.用MTT法测定靶细胞和旁观者细胞活力;并对靶细胞和旁观者细胞进行染色体畸变分析.结果:随着ACTD剂量的增加,靶细胞的活力下降,存在明显的剂量-效应关系(P<0.05).4 mg/L ACTD作用1h时细胞活力接近50%且稳定.旁观者细胞活力在用4-12 h CM培养时逐渐增加(P<0.05),用24h CM时又下降(P<0.05),4h CM诱导旁观者细胞损伤的作用最强.靶细胞的染色体畸变率随ACTD剂量的增加而增高,具有剂量-效应关系(P<.05).旁观者细胞染色体畸变以4hCM诱导的作用最强,随着加入CM时段的延后,损伤逐渐减轻(P<0.05),在24hCM又趋严重(P<0.05);旁观者细胞与靶细胞染色体畸变类型相似,以断裂为主,伴有少量环形染色体、碎片和双着丝粒染色体.结论:ACTD可以诱导旁观者效应的发生,染色体畸变在靶细胞和旁观者细胞均以断裂为主.%OBJECTIVE: To observe the effect of actinomycin D (ACTD) and conditioned medium on cell viability and chromosome aberration in hamster fibroblast V79 cells to determine whether actinomycin D could induce bystander effect. METHODS: V79 cells were treated with ACTD for 1 h at different doses (0, 0.25, 0.5, 1.0, 2.0, 4.0 and 8.0 mg/L). The 4 mg/L ACTD-conditioned medium(CM) was collected at 4, 8, 12 and 24 h after treatment for 1 h to culture bystander cells to observe the bystander effect. Cell viability was evaluated by MTT assay; chromosome damage was detected using the conventional analysis of

  19. Protective Bystander Effects Simulated with the State-Vector Model

    OpenAIRE

    Schöllnberger, Helmut; Peter M. Eckl

    2007-01-01

    Apoptosis induced in non-hit bystander cells is an important biological mechanism which operates after exposure to low doses of low-LET radiation. This process was implemented into a deterministic multistage model for in vitro neoplastic transformation: the State-Vector Model (SVM). The new model is tested on two data sets that show a reduction of the transformation frequency below the spontaneous level after exposure of the human hybrid cell line CGL1 to low doses of γ-radiation. Stronger pr...

  20. Endogenous APOBEC3B restricts LINE-1 retrotransposition in transformed cells and human embryonic stem cells.

    Science.gov (United States)

    Wissing, Silke; Montano, Mauricio; Garcia-Perez, Jose Luis; Moran, John V; Greene, Warner C

    2011-10-21

    Members of the APOBEC3 (A3) family of cytidine deaminase enzymes act as host defense mechanisms limiting both infections by exogenous retroviruses and mobilization of endogenous retrotransposons. Previous studies revealed that the overexpression of some A3 proteins could restrict engineered human Long INterspersed Element-1 (LINE-1 or L1) retrotransposition in HeLa cells. However, whether endogenous A3 proteins play a role in restricting L1 retrotransposition remains largely unexplored. Here, we show that HeLa cells express endogenous A3B and A3C, whereas human embryonic stem cells (hESCs) express A3B, A3C, A3DE, A3F, and A3G. To study the relative contribution of endogenous A3 proteins in restricting L1 retrotransposition, we first generated small hairpin RNAs (shRNAs) to suppress endogenous A3 mRNA expression, and then assessed L1 mobility using a cell-based L1 retrotransposition assay. We demonstrate that in both HeLa and hESCs, shRNA-based knockdown of A3B promotes a ∼2-3.7-fold increase in the retrotransposition efficiency of an engineered human L1. Knockdown of the other A3s produced no significant increase in L1 activity. Thus, A3B appears to restrict engineered L1 retrotransposition in a broad range of cell types, including pluripotent cells.

  1. Differential effects of p53 on bystander phenotypes induced by gamma ray and high LET heavy ion radiation

    Science.gov (United States)

    He, Mingyuan; Dong, Chen; Konishi, Teruaki; Tu, Wenzhi; Liu, Weili; Shiomi, Naoko; Kobayashi, Alisa; Uchihori, Yukio; Furusawa, Yoshiya; Hei, Tom K.; Dang, Bingrong; Shao, Chunlin

    2014-04-01

    High LET particle irradiation has several potential advantages over γ-rays such as p53-independent response. The purpose of this work is to disclose the effect of p53 on the bystander effect induced by different LET irradiations and underlying mechanism. Lymphocyte cells of TK6 (wild type p53) and HMy2.CIR (mutated p53) were exposed to either low or high LET irradiation, then their mitochondrial dysfunction and ROS generation were detected. The micronuclei (MN) induction in HL-7702 hepatocytes co-cultured with irradiated lymphocytes was also measured. It was found that the mitochondrial dysfunction, p66Shc activation, and intracellular ROS were enhanced in TK6 but not in HMy2.CIR cells after γ-ray irradiation, but all of them were increased in both cell lines after carbon and iron irradiation. Consistently, the bystander effect of MN formation in HL-7702 cells was only triggered by γ-irradiated TK6 cells but not by γ-irradiated HMy2.CIR cells. But this bystander effect was induced by both lymphocyte cell lines after heavy ion irradiation. PFT-μ, an inhibitor of p53, only partly inhibited ROS generation and bystander effect induced by 30 keV/μm carbon-irradiated TK6 cells but failed to suppress the bystander effect induced by the TK6 cells irradiated with either 70 keV/μm carbon or 180 keV/μm iron. The mitochondrial inhibitors of rotenone and oligomycin eliminated heavy ion induced ROS generation in TK6 and HMy2.CIR cells and hence diminished the bystander effect on HL-7702 cells. These results clearly demonstrate that the bystander effect is p53-dependent for low LET irradiation, but it is p53-independent for high LET irradiation which may be because of p53-independent ROS generation due to mitochondrial dysfunction.

  2. Improved Anticancer Photothermal Therapy Using the Bystander Effect Enhanced by Antiarrhythmic Peptide Conjugated Dopamine-Modified Reduced Graphene Oxide Nanocomposite.

    Science.gov (United States)

    Yu, Jiantao; Lin, Yu-Hsin; Yang, Lingyan; Huang, Chih-Ching; Chen, Liliang; Wang, Wen-Cheng; Chen, Guan-Wen; Yan, Junyan; Sawettanun, Saranta; Lin, Chia-Hua

    2017-01-01

    Despite tremendous efforts toward developing novel near-infrared (NIR)-absorbing nanomaterials, improvement in therapeutic efficiency remains a formidable challenge in photothermal cancer therapy. This study aims to synthesize a specific peptide conjugated polydopamine-modified reduced graphene oxide (pDA/rGO) nanocomposite that promotes the bystander effect to facilitate cancer treatment using NIR-activated photothermal therapy. To prepare a nanoplatform capable of promoting the bystander effect in cancer cells, we immobilized antiarrhythmic peptide 10 (AAP10) on the surface of dopamine-modified rGO (AAP10-pDA/rGO). Our AAP10-pDA/rGO could promote the bystander effect by increasing the expression of connexin 43 protein in MCF-7 breast-cancer cells. Because of its tremendous ability to absorb NIR absorption, AAP10-pDA/rGO offers a high photothermal effect under NIR irradiation. This leads to a massive death of MCF-7 cells via the bystander effect. Using tumor-bearing mice as the model, it is found that NIR radiation effectively ablates breast tumor in the presence of AAP10-pDA/rGO and inhibits tumor growth by ≈100%. Therefore, this research integrates the bystander and photothermal effects into a single nanoplatform in order to facilitate an efficient photothermal therapy. Furthermore, our AAP10-pDA/rGO, which exhibits both hyperthermia and the bystander effect, can prevent breast-cancer recurrence and, therefore, has great potential for future clinical and research applications.

  3. Radiation-induced bystander effect in healthy G{sub 0} human lymphocytes: Biological and clinical significance

    Energy Technology Data Exchange (ETDEWEB)

    Belloni, Paola; Latini, Paolo [Department of Agrobiology and Agrochemistry, University of Tuscia, Via San Camillo De Lellis, I-01100 Viterbo (Italy); Palitti, Fabrizio, E-mail: palitti@unitus.it [Department of Agrobiology and Agrochemistry, University of Tuscia, Via San Camillo De Lellis, I-01100 Viterbo (Italy)

    2011-08-01

    To study the bystander effects, G{sub 0} human peripheral blood lymphocytes were X-irradiated with 0.1, 0.5 and 3 Gy. After 24 h, cell-free conditioned media from irradiated cultures were transferred to unexposed lymphocytes. Following 48 h of medium transfer, viability, induction of apoptosis, telomere shortening, reactive oxygen species (ROS) levels and micronuclei (after stimulation) were analyzed. A statistically significant decrement in cell viability, concomitant with the loss of mitochondrial membrane potential, telomere shortening, increases in hydrogen peroxide (H{sub 2}O{sub 2}) and superoxide anion (O{sub 2}{sup -}) with depletion of intracellular glutathione (GSH) level, and higher frequencies of micronuclei, were observed in bystander lymphocytes incubated with medium from 0.5 and 3 Gy irradiated samples, compared to lymphocytes unexposed. Furthermore, no statistically significant difference between the response to 0.5 and 3 Gy of irradiation in bystander lymphocytes, was found. However, when lymphocytes were irradiated with 0.1 Gy, no bystander effect with regard to viability, apoptosis, telomere length, and micronuclei was observed, although a high production of ROS level persisted. Radiation in the presence of the radical scavenger dimethyl sulfoxide (DMSO) suppressed oxidative stress induced by 3 Gy of X-rays with the effective elimination of bystander effects, suggesting a correlation between ROS and bystander signal formation in irradiated cells. The data propose that bystander effect might be mostly due to the reactions of radiation induced free radicals on DNA, with the existence of a threshold at which the bystander signal is not operative (0.1 Gy dose of X-rays). Our results may have clinical implications for health risk associated with radiation exposure.

  4. Studies of Bystander Effects in 3-D Tissue Systems Using a Low-LET Microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, David J.

    2009-07-17

    It is now accepted that biological effects may occur in cells that were not themselves traversed by ionizing radiation but are close to those that were. Little is known about the mechanism underlying such a bystander effect, although cell-to-cell communication is thought to be important. Previous work demonstrated a significant bystander effect for clonogenic survival and oncogenic transformation in C3H 10T(1/2) cells. Additional studies were undertaken to assess the importance of the degree of cell-to-cell contact at the time of irradiation on the magnitude of this bystander effect by varying the cell density. When 10% of cells were exposed to a range of 2-12 alpha particles, a significantly greater number of cells were inactivated when cells were irradiated at high density than at low density. In addition, the oncogenic transformation frequency was significantly higher in high-density cultures. These results suggest that when a cell is hit by radiation, the transmission of the bystander signal through cell-to-cell contact is an important mediator of the effect, implicating the involvement of intracellular communication through gap junctions. Additional studies to address the relationship between the bystander effect and the adaptive response were undertaken. A novel apparatus, where targeted and non-targeted cells were grown in close proximity, was used to investigate these. It was further examined whether a bystander effect or an adaptive response could be induced by a factor(s) present in the supernatants of cells exposed to a high or low dose of X-rays, respectively. When non-hit cells were co-cultured for 24 h with cells irradiated with 5 Gy alpha-particles, a significant increase in both cell killing and oncogenic transformation frequency was observed. If these cells were treated with 2 cGy X-rays 5 h before co-culture with irradiated cells, approximately 95% of the bystander effect was cancelled out. A 2.5-fold decrease in the oncogenic transformation

  5. Sulfasalazine unveils a contact-independent HSV-TK/ganciclovir gene therapy bystander effect in malignant gliomas.

    Science.gov (United States)

    Robe, Pierre A; Nguyen-Khac, Minh-Tuan; Lambert, Frederic; Lechanteur, Chantal; Jolois, Olivier; Ernst-Gengoux, Patricia; Rogister, Bernard; Bours, Vincent

    2007-01-01

    The efficacy of HSV-TK/ganciclovir-based gene therapy on malignant gliomas largely relies on the amplitude of the bystander effect. In these experiments, the anti-inflammatory drug Sulfasalazine increased the HSV-TK/ganciclovir bystander effect in C6, 9L and LN18 cells but not in U87 glioma cells. Using bi-compartmental culture devices and conditioned medium transfer experiments, we showed that in C6, 9L and LN18 cells but not in U87 cells, Sulfasalazine also unveiled a new, contact-independent mechanism of HSV-TK/ganciclovir bystander effect. Upon treatment with ganciclovir, human LN18-TK but not U87-TK cells synthetized and released TNF-alpha in the culture medium. Sulfasalazine sensitized glioma cells to the toxic effect of TNF-alpha and enhanced its secretion in LN18-TK cells in response to GCV treatment. The caspase-8 inhibitor Z-IETD-FMK and a blocking antibody to TNF-alpha both inhibited the contact-independent bystander effect in LN18 cells. Taken together, these results suggest that TNF-alpha mediates the contact-independent bystander effect in LN18 cells. The treatment with GCV and/or Sulfasalazine of tumor xenografts consisting of a mix of 98% C6 and 2% C6-TK cells shows that Sulfasalazine is also a potent adjunct to the in vivo treatment of gliomas.

  6. Studies of Bystander Effects in 3-D Tissue Systems Using a Low-LET Microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, David J.

    2009-07-17

    It is now accepted that biological effects may occur in cells that were not themselves traversed by ionizing radiation but are close to those that were. Little is known about the mechanism underlying such a bystander effect, although cell-to-cell communication is thought to be important. Previous work demonstrated a significant bystander effect for clonogenic survival and oncogenic transformation in C3H 10T(1/2) cells. Additional studies were undertaken to assess the importance of the degree of cell-to-cell contact at the time of irradiation on the magnitude of this bystander effect by varying the cell density. When 10% of cells were exposed to a range of 2-12 alpha particles, a significantly greater number of cells were inactivated when cells were irradiated at high density than at low density. In addition, the oncogenic transformation frequency was significantly higher in high-density cultures. These results suggest that when a cell is hit by radiation, the transmission of the bystander signal through cell-to-cell contact is an important mediator of the effect, implicating the involvement of intracellular communication through gap junctions. Additional studies to address the relationship between the bystander effect and the adaptive response were undertaken. A novel apparatus, where targeted and non-targeted cells were grown in close proximity, was used to investigate these. It was further examined whether a bystander effect or an adaptive response could be induced by a factor(s) present in the supernatants of cells exposed to a high or low dose of X-rays, respectively. When non-hit cells were co-cultured for 24 h with cells irradiated with 5 Gy alpha-particles, a significant increase in both cell killing and oncogenic transformation frequency was observed. If these cells were treated with 2 cGy X-rays 5 h before co-culture with irradiated cells, approximately 95% of the bystander effect was cancelled out. A 2.5-fold decrease in the oncogenic transformation

  7. Infection-induced bystander-apoptosis of monocytes is TNF-alpha-mediated.

    Directory of Open Access Journals (Sweden)

    Stephan Dreschers

    Full Text Available Phagocytosis induced cell death (PICD is crucial for controlling phagocyte effector cells, such as monocytes, at sites of infection, and essentially contributes to termination of inflammation. Here we tested the hypothesis, that during PICD bystander apoptosis of non-phagocyting monocytes occurs, that apoptosis induction is mediated via tumor necrosis factor-alpha (TNF-α and that TNF-α secretion and -signalling is causal. Monocytes were infected with Escherichia coli (E. coli, expressing green fluorescent protein (GFP, or a pH-sensitive Eos-fluorescent protein (EOS-FP. Monocyte phenotype, phagocytic activity, apoptosis, TNF-receptor (TNFR-1, -2-expression and TNF-α production were analyzed. Apoptosis occured in phagocyting and non-phagocyting, bystander monocytes. Bacterial transport to the phagolysosome was no prerequisite for apoptosis induction, and desensitized monocytes from PICD, as confirmed by EOS-FP expressing E. coli. Co-cultivation with non-infected carboxyfluorescein-succinimidyl-ester- (CFSE- labelled monocytes resulted in significant apoptotic cell death of non-infected bystander monocytes. This process required protein de-novo synthesis and still occurred in a diminished way in the absence of cell-cell contact. E. coli induced a robust TNF-α production, leading to TNF-mediated apoptosis in monocytes. Neutralization with an anti-TNF-α antibody reduced monocyte bystander apoptosis significantly. In contrast to TNFR2, the pro-apoptotic TNFR1 was down-regulated on the monocyte surface, internalized 30 min. p.i. and led to apoptosis predominantly in monocytes without phagocyting bacteria by themselves. Our results suggest, that apoptosis of bystander monocytes occurs after infection with E. coli via internalization of TNFR1, and indicate a relevant role for TNF-α. Modifying monocyte apoptosis in sepsis may be a future therapeutic option.

  8. Restricted 12p Amplification and RAS Mutation in Human Germ Cell Tumors of the Adult Testis

    Science.gov (United States)

    Roelofs, Helene; Mostert, Marijke C.; Pompe, Kirsten; Zafarana, Gaetano; van Oorschot, Monique; van Gurp, Ruud J. H. L. M.; Gillis, Ad J. M.; Stoop, Hans; Beverloo, Berna; Oosterhuis, J. Wolter; Bokemeyer, Carsten; Looijenga, Leendert H. J.

    2000-01-01

    Human testicular germ-cell tumors of young adults (TGCTs), both seminomas and nonseminomas, are characterized by 12p overrepresentation, mostly as isochromosomes, of which the biological and clinical significance is still unclear. A limited number of TGCTs has been identified with an additional high-level amplification of a restricted region of 12p including the K-RAS proto-oncogene. Here we show that the incidence of these restricted 12p amplifications is ∼8% in primary TGCTs. Within a single cell formation of i(12p) and restricted 12p amplification is mutually exclusive. The borders of the amplicons cluster in short regions, and the amplicon was never found in the adjacent carcinoma in situ cells. Seminomas with the restricted 12p amplification virtually lacked apoptosis and the tumor cells showed prolonged in vitro survival like seminoma cells with a mutated RAS gene. However, no differences in proliferation index between these different groups of seminomas were found. Although patients with a seminoma containing a homogeneous restricted 12p amplification presented at a significantly younger age than those lacking it, the presence of a restricted 12p amplification/RAS mutation did not predict the stage of the disease at clinical presentation and the treatment response of primary seminomas. In 55 primary and metastatic tumors from 44 different patients who failed cisplatinum-based chemotherapy, the restricted 12p amplification and RAS mutations had the same incidence as in the consecutive series of responding patients. These data support the model that gain of 12p in TGCTs is related to invasive growth. It allows tumor cells, in particular those showing characteristics of early germ cells (ie, the seminoma cells), to survive outside their specific microenvironment. Overexpression of certain genes on 12p probably inhibits apoptosis in these tumor cells. However, the copy numbers of the restricted amplification of 12p and K-RAS mutations do not predict response

  9. Chimpanzees' Bystander Reactions to Infanticide: An Evolutionary Precursor of Social Norms?

    Science.gov (United States)

    von Rohr, Claudia Rudolf; van Schaik, Carel P; Kissling, Alexandra; Burkart, Judith M

    2015-06-01

    Social norms-generalized expectations about how others should behave in a given context-implicitly guide human social life. However, their existence becomes explicit when they are violated because norm violations provoke negative reactions, even from personally uninvolved bystanders. To explore the evolutionary origin of human social norms, we presented chimpanzees with videos depicting a putative norm violation: unfamiliar conspecifics engaging in infanticidal attacks on an infant chimpanzee. The chimpanzees looked far longer at infanticide scenes than at control videos showing nut cracking, hunting a colobus monkey, or displays and aggression among adult males. Furthermore, several alternative explanations for this looking pattern could be ruled out. However, infanticide scenes did not generally elicit higher arousal. We propose that chimpanzees as uninvolved bystanders may detect norm violations but may restrict emotional reactions to such situations to in-group contexts. We discuss the implications for the evolution of human morality.

  10. N-cadherin-mediated cell adhesion restricts cell proliferation in the dorsal neural tube.

    Science.gov (United States)

    Chalasani, Kavita; Brewster, Rachel M

    2011-05-01

    Neural progenitors are organized as a pseudostratified epithelium held together by adherens junctions (AJs), multiprotein complexes composed of cadherins and α- and β-catenin. Catenins are known to control neural progenitor division; however, it is not known whether they function in this capacity as cadherin binding partners, as there is little evidence that cadherins themselves regulate neural proliferation. We show here that zebrafish N-cadherin (N-cad) restricts cell proliferation in the dorsal region of the neural tube by regulating cell-cycle length. We further reveal that N-cad couples cell-cycle exit and differentiation, as a fraction of neurons are mitotic in N-cad mutants. Enhanced proliferation in N-cad mutants is mediated by ligand-independent activation of Hedgehog (Hh) signaling, possibly caused by defective ciliogenesis. Furthermore, depletion of Hh signaling results in the loss of junctional markers. We therefore propose that N-cad restricts the response of dorsal neural progenitors to Hh and that Hh signaling limits the range of its own activity by promoting AJ assembly. Taken together, these observations emphasize a key role for N-cad-mediated adhesion in controlling neural progenitor proliferation. In addition, these findings are the first to demonstrate a requirement for cadherins in synchronizing cell-cycle exit and differentiation and a reciprocal interaction between AJs and Hh signaling.

  11. Brief report: The bystander effect in cyberbullying incidents.

    Science.gov (United States)

    Machackova, Hana; Dedkova, Lenka; Mezulanikova, Katerina

    2015-08-01

    This study examined the bystander effect in cyberbullying. Using self-reported data from 257 Czech respondents who had witnessed a cyberbullying attack, we tested whether provided help decreased with increased number of other bystanders. We controlled for several individual and contextual factors, including empathy, social self-efficacy, empathic response to victimization, and relationship to the victim. Results showed that participants tend to help the victims more in incidents with only one or two other bystanders. We also found that, as in the "offline" realm, bystander effect is not linear: no significant differences were found between incidents with a moderate number (3-10) and a larger number of total bystanders. Our findings, thus, provide support for the presence of the bystander effect in cyberbullying.

  12. CD1-Restricted T Cells at the Crossroad of Innate and Adaptive Immunity

    Science.gov (United States)

    Pereira, Catia S.

    2016-01-01

    Lipid-specific T cells comprise a group of T cells that recognize lipids bound to the MHC class I-like CD1 molecules. There are four isoforms of CD1 that are expressed at the surface of antigen presenting cells and therefore capable of presenting lipid antigens: CD1a, CD1b, CD1c, and CD1d. Each one of these isoforms has distinct structural features and cellular localizations, which promotes binding to a broad range of different types of lipids. Lipid antigens originate from either self-tissues or foreign sources, such as bacteria, fungus, or plants and their recognition by CD1-restricted T cells has important implications in infection but also in cancer and autoimmunity. In this review, we describe the characteristics of CD1 molecules and CD1-restricted lipid-specific T cells, highlighting the innate-like and adaptive-like features of different CD1-restricted T cell subtypes. PMID:28070524

  13. Restriction of Rift Valley Fever Virus Virulence in Mosquito Cells

    Directory of Open Access Journals (Sweden)

    Sonja R. Gerrard

    2010-02-01

    Full Text Available Arboviruses are maintained in a natural cycle that requires blood-sucking arthropod and vertebrate hosts. Arboviruses are believed to persistently infect their arthropod host without overt pathology and cause acute infection with viremia in their vertebrate host. We have focused on elucidating how a specific arbovirus, Rift Valley fever (RVF virus, causes cytopathic effect in cells derived from vertebrates and non-cytopathic infection in cells derived from arthropods. We demonstrate that the vertebrate virulence factor, NSs, is functional in arthropod cells but is expressed at significantly lower levels in infected arthropod versus infected vertebrate cells.

  14. The Role of DNA Methylation Changes in Radiation-Induced Bystander Effects in cranial irradiated Mice

    Science.gov (United States)

    Zhang, Meng; Sun, Yeqing; Xue, Bei; Wang, Xinwen; Wang, Jiawen

    2016-07-01

    Heavy-ion radiation could lead to bystander effect in neighboring non-hit cells by signals released from directly-irradiated cells. The exact mechanisms of radiation-induced bystander effect in distant organ remain obscure, yet accumulating evidence points to the role of DNA methylation changes in bystander effect. To identify the molecular mechanism that underlies bystander effects of heavy-ion radiation, the male Balb/c and C57BL mice were cranial exposed to 40, 200, 2000mGy dose of carbon heavy-ion radiation, while the rest of the animal body was shielded. The γH2AX foci as the DNA damage biomarker in directly irradiation organ ear and the distant organ liver were detected on 0, 1, 2, 6, 12 and 24h after radiation, respectively. Methylation-sensitive amplifcation polymorphism (MSAP) was used to monitor the level of polymorphic genomic DNA methylation changed with dose and time effects. The results show that cranial irradiated mice could induce the γH2AX foci and genomic DNA methylation changes significantly in both the directly irradiation organ ear and the distant organ liver. The percent of DNA methylation changes were time-dependent and tissue-specific. Demethylation polymorphism rate were highest separately at 1 h in 200 mGy and 6 h in 2000 mGy after irradiation in ear. The global DNA methylation changes tended to occur in the CG sites. We also found that the numbers of γH2AX foci and the genomic methylation changes of heavy-ion radiation-induced bystander effect in liver could be obvious 1 h after radiation and achieved the maximum at 6 h, while the changes could recover gradually at 12 h. The results suggest that mice head exposed to heavy-ion radiation can induce damage and methylation pattern changed in both directly radiation organ ear and distant organ liver. Moreover, our findings are important to understand the molecular mechanism of radiation induced bystander effects in vivo. Keywords: Heavy-ion radiation; Bystander effect; DNA methylation; γH2

  15. Neutron induced bystander effect among zebrafish embryos

    Science.gov (United States)

    Ng, C. Y. P.; Kong, E. Y.; Kobayashi, A.; Suya, N.; Uchihori, Y.; Cheng, S. H.; Konishi, T.; Yu, K. N.

    2015-12-01

    The present paper reported the first-ever observation of neutron induced bystander effect (NIBE) using zebrafish (Danio rerio) embryos as the in vivo model. The neutron exposure in the present work was provided by the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility at the National Institute of Radiological Sciences (NIRS), Chiba, Japan. Two different strategies were employed to induce NIBE, namely, through directly partnering and through medium transfer. Both results agreed with a neutron-dose window (20-50 mGy) which could induce NIBE. The lower dose limit corresponded to the threshold amount of neutron-induced damages to trigger significant bystander signals, while the upper limit corresponded to the onset of gamma-ray hormesis which could mitigate the neutron-induced damages and thereby suppress the bystander signals. Failures to observe NIBE in previous studies were due to using neutron doses outside the dose-window. Strategies to enhance the chance of observing NIBE included (1) use of a mono-energetic high-energy (e.g., between 100 keV and 2 MeV) neutron source, and (2) use of a neutron source with a small gamma-ray contamination. It appeared that the NASBEE facility used in the present study fulfilled both conditions, and was thus ideal for triggering NIBE.

  16. Auxin regulates SNARE-dependent vacuolar morphology restricting cell size.

    Science.gov (United States)

    Löfke, Christian; Dünser, Kai; Scheuring, David; Kleine-Vehn, Jürgen

    2015-03-05

    The control of cellular growth is central to multicellular patterning. In plants, the encapsulating cell wall literally binds neighbouring cells to each other and limits cellular sliding/migration. In contrast to its developmental importance, growth regulation is poorly understood in plants. Here, we reveal that the phytohormone auxin impacts on the shape of the biggest plant organelle, the vacuole. TIR1/AFBs-dependent auxin signalling posttranslationally controls the protein abundance of vacuolar SNARE components. Genetic and pharmacological interference with the auxin effect on vacuolar SNAREs interrelates with auxin-resistant vacuolar morphogenesis and cell size regulation. Vacuolar SNARE VTI11 is strictly required for auxin-reliant vacuolar morphogenesis and loss of function renders cells largely insensitive to auxin-dependent growth inhibition. Our data suggests that the adaptation of SNARE-dependent vacuolar morphogenesis allows auxin to limit cellular expansion, contributing to root organ growth rates.

  17. Complement-Opsonized HIV-1 Overcomes Restriction in Dendritic Cells.

    Directory of Open Access Journals (Sweden)

    Wilfried Posch

    2015-06-01

    Full Text Available DCs express intrinsic cellular defense mechanisms to specifically inhibit HIV-1 replication. Thus, DCs are productively infected only at very low levels with HIV-1, and this non-permissiveness of DCs is suggested to go along with viral evasion. We now illustrate that complement-opsonized HIV-1 (HIV-C efficiently bypasses SAMHD1 restriction and productively infects DCs including BDCA-1 DCs. Efficient DC infection by HIV-C was also observed using single-cycle HIV-C, and correlated with a remarkable elevated SAMHD1 T592 phosphorylation but not SAMHD1 degradation. If SAMHD1 phosphorylation was blocked using a CDK2-inhibitor HIV-C-induced DC infection was also significantly abrogated. Additionally, we found a higher maturation and co-stimulatory potential, aberrant type I interferon expression and signaling as well as a stronger induction of cellular immune responses in HIV-C-treated DCs. Collectively, our data highlight a novel protective mechanism mediated by complement opsonization of HIV to effectively promote DC immune functions, which might be in the future exploited to tackle HIV infection.

  18. Endothelial progenitor cells display clonal restriction in multiple myeloma

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    Dai Kezhi

    2006-06-01

    Full Text Available Abstract Background In multiple myeloma (MM, increased neoangiogenesis contributes to tumor growth and disease progression. Increased levels of endothelial progenitor cells (EPCs contribute to neoangiogenesis in MM, and, importantly, covary with disease activity and response to treatment. In order to understand the mechanisms responsible for increased EPC levels and neoangiogenic function in MM, we investigated whether these cells were clonal by determining X-chromosome inactivation (XCI patterns in female patients by a human androgen receptor assay (HUMARA. In addition, EPCs and bone marrow cells were studied for the presence of clonotypic immunoglobulin heavy-chain (IGH gene rearrangement, which indicates clonality in B cells; thus, its presence in EPCs would indicate a close genetic link between tumor cells in MM and endothelial cells that provide tumor neovascularization. Methods A total of twenty-three consecutive patients who had not received chemotherapy were studied. Screening in 18 patients found that 11 displayed allelic AR in peripheral blood mononuclear cells, and these patients were further studied for XCI patterns in EPCs and hair root cells by HUMARA. In 2 patients whose EPCs were clonal by HUMARA, and in an additional 5 new patients, EPCs were studied for IGH gene rearrangement using PCR with family-specific primers for IGH variable genes (VH. Results In 11 patients, analysis of EPCs by HUMARA revealed significant skewing (≥ 77% expression of a single allele in 64% (n = 7. In 4 of these patients, XCI skewing was extreme (≥ 90% expression of a single allele. In contrast, XCI in hair root cells was random. Furthermore, PCR amplification with VH primers resulted in amplification of the same product in EPCs and bone marrow cells in 71% (n = 5 of 7 patients, while no IGH rearrangement was found in EPCs from healthy controls. In addition, in patients with XCI skewing in EPCs, advanced age was associated with poorer clinical status

  19. High expression of CD26 accurately identifies human bacteria-reactive MR1-restricted MAIT cells.

    Science.gov (United States)

    Sharma, Prabhat K; Wong, Emily B; Napier, Ruth J; Bishai, William R; Ndung'u, Thumbi; Kasprowicz, Victoria O; Lewinsohn, Deborah A; Lewinsohn, David M; Gold, Marielle C

    2015-07-01

    Mucosa-associated invariant T (MAIT) cells express the semi-invariant T-cell receptor TRAV1-2 and detect a range of bacteria and fungi through the MHC-like molecule MR1. However, knowledge of the function and phenotype of bacteria-reactive MR1-restricted TRAV1-2(+) MAIT cells from human blood is limited. We broadly characterized the function of MR1-restricted MAIT cells in response to bacteria-infected targets and defined a phenotypic panel to identify these cells in the circulation. We demonstrated that bacteria-reactive MR1-restricted T cells shared effector functions of cytolytic effector CD8(+) T cells. By analysing an extensive panel of phenotypic markers, we determined that CD26 and CD161 were most strongly associated with these T cells. Using FACS to sort phenotypically defined CD8(+) subsets we demonstrated that high expression of CD26 on CD8(+)  TRAV1-2(+) cells identified with high specificity and sensitivity, bacteria-reactive MR1-restricted T cells from human blood. CD161(hi) was also specific for but lacked sensitivity in identifying all bacteria-reactive MR1-restricted T cells, some of which were CD161(dim) . Using cell surface expression of CD8, TRAV1-2, and CD26(hi) in the absence of stimulation we confirm that bacteria-reactive T cells are lacking in the blood of individuals with active tuberculosis and are restored in the blood of individuals undergoing treatment for tuberculosis.

  20. Calorie restriction-mediated replicative lifespan extension in yeast is non-cell autonomous.

    Directory of Open Access Journals (Sweden)

    Szu-Chieh Mei

    2015-01-01

    Full Text Available In laboratory yeast strains with Sir2 and Fob1 function, wild-type NAD+ salvage is required for calorie restriction (CR to extend replicative lifespan. CR does not significantly alter steady state levels of intracellular NAD+ metabolites. However, levels of Sir2 and Pnc1, two enzymes that sequentially convert NAD+ to nicotinic acid (NA, are up-regulated during CR. To test whether factors such as NA might be exported by glucose-restricted mother cells to survive later generations, we developed a replicative longevity paradigm in which mother cells are moved after 15 generations on defined media. The experiment reveals that CR mother cells lose the longevity benefit of CR when evacuated from their local environment to fresh CR media. Addition of NA or nicotinamide riboside (NR allows a moved mother to maintain replicative longevity despite the move. Moreover, conditioned medium from CR-treated cells transmits the longevity benefit of CR to moved mother cells. Evidence suggests the existence of a longevity factor that is dialyzable but is neither NA nor NR, and indicates that Sir2 is not required for the longevity factor to be produced or to act. Data indicate that the benefit of glucose-restriction is transmitted from cell to cell in budding yeast, suggesting that glucose restriction may benefit neighboring cells and not only an individual cell.

  1. Sleep restriction by forced activity reduces hippocampal cell proliferation

    NARCIS (Netherlands)

    Roman, Viktor; Van der Borght, K; Leemburg, SA; Van der Zee, EA; Meerlo, P

    2005-01-01

    Mounting evidence suggests that sleep loss negatively affects learning and memory processes through disruption of hippocampal function. In the present study, we examined whether sleep loss alters the generation, differentiation, and survival of new cells in the dentate gyrus. Rats were sleep restric

  2. Vasodilator-stimulated phosphoprotein restricts cell-to-cell spread of Shigella flexneri at the cell periphery.

    Science.gov (United States)

    Lee, Soo Young; Gertler, Frank B; Goldberg, Marcia B

    2015-11-01

    Shigella spp. are intracellular bacterial pathogens that cause diarrhoeal disease in humans. Shigella utilize the host actin cytoskeleton to enter cells, move through the cytoplasm of cells and pass into adjacent cells. Ena/VASP family proteins are highly conserved proteins that participate in actin-dependent dynamic cellular processes. We tested whether Ena/VASP family members VASP (vasodilator-stimulated phosphoprotein), Mena (mammalian-enabled) or EVL (Ena-VASP-like) contribute to Shigella flexneri spread through cell monolayers. VASP and EVL restricted cell-to-cell spread without significantly altering actin-based motility, whereas Mena had no effect on these processes. Phosphorylation of VASP on Ser153, Ser235 and Thr274 regulated its subcellular distribution and function. VASP derivatives that lack the Ena/VASP homology 1 (EVH1) domain or contain a phosphoablative mutation of Ser153 were defective in restricting S. flexneri spread, indicating that the EVH1 domain and phosphorylation on Ser153 are required for this process. The EVH1 domain and Ser153 of VASP were required for VASP localization to focal adhesions, and localization of VASP to focal adhesions and/or the leading edge was required for restriction of spread. The contribution of the EVH1 domain was from both the donor and the recipient cell, whereas the contribution of Ser153 phosphorylation was only from the donor cell. Thus, unlike host proteins characterized in Shigella pathogenesis that promote bacterial spread, VASP and EVL function to limit it. The ability of VASP and EVL to limit spread highlights the critical role of focal adhesion complexes and/or the leading edge in bacterial passage between cells.

  3. Measuring Bystander Attitudes and Behavior to Prevent Sexual Violence

    Science.gov (United States)

    McMahon, Sarah; Allen, Christopher T.; Postmus, Judy L.; McMahon, Sheila M.; Peterson, N. Andrew; Lowe Hoffman, Melanie

    2014-01-01

    Objective: The purpose of this study is to further investigate the factor structure and strength of the Bystander Attitude Scale-Revised and Bystander Behavior Scale-Revised (BAS-R and BBS-R). Participants: First-year students (N = 4,054) at a large public university in the Northeast completed a survey in 2010 as part of a larger longitudinal…

  4. The Bystander in Commercial Life : Obliged by Beneficence or Rescue

    NARCIS (Netherlands)

    Dubbink, Wim

    2016-01-01

    Liberalist thinking argues that moral agents have a right (or duty) to pursue an ordinary life. It also insists that moral agent can be bystanders. A bystander is involved with morally bad states of affairs in the sense that they are bound by moral duty, but for a non-blameworthy reason. A common vi

  5. The lonely bystander: ostracism leads to less helping in virtual bystander situations

    NARCIS (Netherlands)

    Bommel, van Marco; Prooijen, van Jan-Willem; Elffers, Henk; Lange, van Paul A.M.

    2016-01-01

    People are less likely to help when they have been ostracized, or when they are in the presence of bystanders. In the current manuscript we test both these influences simultaneously. We postulated two opposing hypotheses: first, helping decreases after ostracism, even when intervention is already le

  6. Caloric restriction suppresses apoptotic cell death in the mammalian cochlea and leads to prevention of presbycusis.

    Science.gov (United States)

    Someya, Shinichi; Yamasoba, Tatsuya; Weindruch, Richard; Prolla, Tomas A; Tanokura, Masaru

    2007-10-01

    Presbycusis is characterized by an age-related progressive decline of auditory function, and arises mainly from the degeneration of hair cells or spiral ganglion (SG) cells in the cochlea. Here we show that caloric restriction suppresses apoptotic cell death in the mouse cochlea and prevents late onset of presbycusis. Calorie restricted (CR) mice, which maintained body weight at the same level as that of young control (YC) mice, retained normal hearing and showed no cochlear degeneration. CR mice also showed a significant reduction in the number of TUNEL-positive cells and cleaved caspase-3-positive cells relative to middle-age control (MC) mice. Microarray analysis revealed that CR down-regulated the expression of 24 apoptotic genes, including Bak and Bim. Taken together, our findings suggest that loss of critical cells through apoptosis is an important mechanism of presbycusis in mammals, and that CR can retard this process by suppressing apoptosis in the inner ear tissue.

  7. Adenoviral delivery of pan-caspase inhibitor p35 enhances bystander killing by P450 gene-directed enzyme prodrug therapy using cyclophosphamide+

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    Doloff Joshua C

    2010-09-01

    Full Text Available Abstract Background Cytochrome P450-based suicide gene therapy for cancer using prodrugs such as cyclophosphamide (CPA increases anti-tumor activity, both directly and via a bystander killing mechanism. Bystander cell killing is essential for the clinical success of this treatment strategy, given the difficulty of achieving 100% efficient gene delivery in vivo using current technologies. Previous studies have shown that the pan-caspase inhibitor p35 significantly increases CPA-induced bystander killing by tumor cells that stably express P450 enzyme CYP2B6 (Schwartz et al, (2002 Cancer Res. 62: 6928-37. Methods To further develop this approach, we constructed and characterized a replication-defective adenovirus, Adeno-2B6/p35, which expresses p35 in combination with CYP2B6 and its electron transfer partner, P450 reductase. Results The expression of p35 in Adeno-2B6/p35-infected tumor cells inhibited caspase activation, delaying the death of the CYP2B6 "factory" cells that produce active CPA metabolites, and increased bystander tumor cell killing compared to that achieved in the absence of p35. Tumor cells infected with Adeno-2B6/p35 were readily killed by cisplatin and doxorubicin, indicating that p35 expression is not associated with acquisition of general drug resistance. Finally, p35 did not inhibit viral release when the replication-competent adenovirus ONYX-017 was used as a helper virus to facilitate co-replication and spread of Adeno-2B6/p35 and further increase CPA-induced bystander cell killing. Conclusions The introduction of p35 into gene therapeutic regimens constitutes an effective approach to increase bystander killing by cytochrome P450 gene therapy. This strategy may also be used to enhance other bystander cytotoxic therapies, including those involving the production of tumor cell toxic protein products.

  8. Apoptosis is signalled early by low doses of ionising radiation in a radiation-induced bystander effect

    Energy Technology Data Exchange (ETDEWEB)

    Furlong, Hayley, E-mail: hayley.furlong@dit.ie [DIT Centre for Radiation and Environmental Science, Focas Research Institute, Dublin Institute of Technology, Kevin St, Dublin 8 (Ireland); School of Biological Sciences, College of Sciences and Health, Dublin Institute of Technology, Kevin St, Dublin 8 (Ireland); Mothersill, Carmel [Medical Physics and Applied Radiation Sciences, Nuclear Research Building, 1280 Hamilton, Ontario L8S 4K1 (Canada); Lyng, Fiona M. [DIT Centre for Radiation and Environmental Science, Focas Research Institute, Dublin Institute of Technology, Kevin St, Dublin 8 (Ireland); Howe, Orla [DIT Centre for Radiation and Environmental Science, Focas Research Institute, Dublin Institute of Technology, Kevin St, Dublin 8 (Ireland); School of Biological Sciences, College of Sciences and Health, Dublin Institute of Technology, Kevin St, Dublin 8 (Ireland)

    2013-01-15

    Highlights: ► Molecular mechanisms involved in the production of a radiation induced bystander effect are not well known. ► We investigate gene expression changes in apoptotic genes in both direct and bystander responses. ► We demonstrate initiation of the apoptotic cascade in a bystander response. ► Lower doses reveal a specific but differential response related to apoptosis compared to higher doses. - Abstract: It is known that ionising radiation (IR) induces a complex signalling apoptotic cascade post-exposure to low doses ultimately to remove damaged cells from a population, specifically via the intrinsic pathway. Therefore, it was hypothesised that bystander reporter cells may initiate a similar apoptotic response if exposed to low doses of IR (0.05 Gy and 0.5 Gy) and compared to directly irradiated cells. Key apoptotic genes were selected according to their role in the apoptotic cascade; tumour suppressor gene TP53, pro-apoptotic Bax and anti-apoptotic Bcl2, pro-apoptotic JNK and anti-apoptotic ERK, initiator caspase 2 and 9 and effector caspase 3, 6 and 7. The data generated consolidated the role of apoptosis following direct IR exposure for all doses and time points as pro-apoptotic genes such as Bax and JNK as well as initiator caspase 7 and effector caspase 3 and 9 were up-regulated. However, the gene expression profile for the bystander response was quite different and more complex in comparison to the direct response. The 0.05 Gy dose point had a more significant apoptosis gene expression profile compared to the 0.5 Gy dose point and genes were not always expressed within 1 h but were sometimes expressed 24 h later. The bystander data clearly demonstrates initiation of the apoptotic cascade by the up-regulation of TP53, Bax, Bcl-2, initiator caspase 2 and effector caspase 6. The effector caspases 3 and 7 of the bystander samples demonstrated down-regulation in their gene expression levels at 0.05 Gy and 0.5 Gy at both time points therefore not

  9. The Bystander-Effect: A Meta-Analytic Review on Bystander Intervention in Dangerous and Non-Dangerous Emergencies

    Science.gov (United States)

    Fischer, Peter; Krueger, Joachim I.; Greitemeyer, Tobias; Vogrincic, Claudia; Kastenmuller, Andreas; Frey, Dieter; Heene, Moritz; Wicher, Magdalena; Kainbacher, Martina

    2011-01-01

    Research on bystander intervention has produced a great number of studies showing that the presence of other people in a critical situation reduces the likelihood that an individual will help. As the last systematic review of bystander research was published in 1981 and was not a quantitative meta-analysis in the modern sense, the present…

  10. The Significance of the Bystander Effect: Modeling, Experiments, and More Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, David J.

    2009-07-22

    Non-targeted (bystander) effects of ionizing radiation are caused by intercellular signaling; they include production of DNA damage and alterations in cell fate (i.e. apoptosis, differentiation, senescence or proliferation). Biophysical models capable of quantifying these effects may improve cancer risk estimation at radiation doses below the epidemiological detection threshold. Understanding the spatial patterns of bystander responses is important, because it provides estimates of how many bystander cells are affected per irradiated cell. In a first approach to modeling of bystander spatial effects in a three-dimensional artificial tissue, we assumed the following: (1) The bystander phenomenon results from signaling molecules (S) that rapidly propagate from irradiated cells and decrease in concentration (exponentially in the case of planar symmetry) as distance increases. (2) These signals can convert cells to a long-lived epigenetically activated state, e.g. a state of oxidative stress; cells in this state are more prone to DNA damage and behavior alterations than normal and therefore exhibit an increased response (R) for many end points (e.g. apoptosis, differentiation, micronucleation). These assumptions were implemented by a mathematical formalism and computational algorithms. The model adequately described data on bystander responses in the 3D system using a small number of adjustable parameters. Mathematical models of radiation carcinogenesis are important for understanding mechanisms and for interpreting or extrapolating risk. There are two classes of such models: (1) long-term formalisms that track pre-malignant cell numbers throughout an entire lifetime but treat initial radiation dose-response simplistically and (2) short-term formalisms that provide a detailed initial dose-response even for complicated radiation protocols, but address its modulation during the subsequent cancer latency period only indirectly. We argue that integrating short- and long

  11. Enteropathogenic Escherichia coli: foe or innocent bystander?

    Science.gov (United States)

    Hu, J; Torres, A G

    2015-08-01

    Enteropathogenic Escherichia coli (EPEC) remain one the most important pathogens infecting children and they are one of the main causes of persistent diarrhoea worldwide. Historically, typical EPEC (tEPEC), defined as those isolates with the attaching and effacement (A/E) genotype (eae(+)), which possess bfpA(+) and lack the stx(-) genes are found strongly associated with diarrhoeal cases. However, occurrence of atypical EPEC (aEPEC; eae(+)bfpA(-)stx(-)) in diarrhoeal and asymptomatic hosts has made investigators question the role of these pathogens in human disease. Current epidemiological data are helping to answer the question of whether EPEC is mainly a foe or an innocent bystander during infection.

  12. What is the role of the bystander response in radionuclide therapies?

    Directory of Open Access Journals (Sweden)

    Darren eBrady

    2013-08-01

    Full Text Available Radionuclide therapy for cancer is undergoing a renaissance, with a wide range of radionuclide and clinical delivery systems currently under investigation. Dosimetry at the cellular and subcellular level is complex with inhomogeneity and incomplete targeting of all cells such that some tumour cells will receive little or no direct radiation energy. There is now sufficient preclinical evidence of a bystander response which can modulate the biology of these unirradiated cells with current research demonstrating both protective and inhibitory responses. Dependence upon fraction of irradiated cells has also been found has and the presence of functional gap junctions appears to be import for several bystander responses. The selection of either high or low LET radionuclides may be critical. While low LET radionuclides appear to have a bystander response proportional to dose, the dose-response from high LET radionuclides are more complex. In media transfer experiments a U shaped response curve has been demonstrated for high LET treatments. However this U shaped response has not been seen with co-culture experiments and its relevance remains uncertain. For high LET treatments there is a suggestion that dose rate effects may also be important with inhibitory effects noted with 125I labelling study and a stimulatory seen with 123I labelling in one study.

  13. MR1-restricted mucosal-associated invariant T cells and their activation during infectious diseases

    Directory of Open Access Journals (Sweden)

    Lauren J. Howson

    2015-06-01

    Full Text Available MR1-restricted MAIT cells recognize vitamin B metabolites, which are generated by a broad range of bacteria, from Escherichia coli to Mycobacterium tuberculosis and BCG. MAIT cells have been described as innate sensors of infection as they accumulate early in infected tissues. MAIT cells maintain an activated phenotype throughout the course of infections, secrete inflammatory cytokines and have the potential to directly kill infected cells, playing an important role in shaping the host response. In this review, we will discuss the current knowledge regarding the molecular mechanisms that underline MAIT cells activation in sterile and non-sterile inflammatory conditions.

  14. Effects of melatonin or maternal nutrient restriction on vascularity and cell proliferation in the ovine placenta

    Science.gov (United States)

    Previously we reported increased umbilical artery blood flow in ewes supplemented with melatonin from mid- to late-pregnancy, while maternal nutrient restriction decreased uterine artery blood flow. To further unravel these responses, this study was designed to assess placental cell proliferation an...

  15. Severe cell reduction in the future brain cortex in human growth-restricted fetuses and infants

    DEFF Research Database (Denmark)

    Samuelsen, Grethe B; Pakkenberg, Bente; Bogdanović, Nenad;

    2007-01-01

    OBJECTIVE: The objective of the study was to test the hypothesis that the total number of cells in the cortical part of the cerebral wall is the same in intrauterine growth-restricted (IUGR) fetuses, compared with normally grown fetuses. STUDY DESIGN: The total cell number in the cerebral wall...... with controls. The daily increase in brain cells in the future cortex was only half of that of the controls. In the 3 other developmental zones, no significant differences in cell numbers could be demonstrated. CONCLUSIONS: IUGR in humans is associated with a severe reduction in cortical growth...

  16. Exposures involving perturbations of the EM field have non-linear effects on radiation response and can alter the expression of radiation induced bystander effects

    Science.gov (United States)

    Mothersill, Carmel; Seymour, Colin

    2012-07-01

    Our recent data suggest there is a physical component to the bystander signal induced by radiation exposure and that alternative medicine techniques such as Reiki and acupuncture or exposures to weak EM fields alter the response of cells to direct irradiation and either altered bystander signal production or altered the response of cells receiving bystander signals. Our proposed mechanism to explain these findings is that perturbation of electromagnetic (EM) fields is central to the induction of low radiation dose responses especially non-targeted bystander effects. In this presentation we review the alternative medicine data and other data sets from our laboratory which test our hypothesis that perturbation of bio-fields will modulate radiation response in the low dose region. The other data sets include exposure to MRI, shielding using lead and or Faraday cages, the use of physical barriers to bystander signal transmission and the use of membrane channel blockers. The data taken together strongly suggest that EM field perturbation can modulate low dose response and that in fact the EM field rather than the targeted deposition of ionizing energy in the DNA may be the key determinant of dose response in a cell or organism The results also lead us to suspect that at least when chemical transmission is blocked, bystander signals can be transmitted by other means. Our recent experiments suggest light signals and volatiles are not likely. We conclude that alternative medicine and other techniques involving electromagnetic perturbations can modify the response of cells to low doses of ionizing radiation and can induce bystander effects similar to those seen in medium transfer experiments. In addition to the obvious implications for mechanistic studies of low dose effects, this could perhaps provide a novel target to exploit in space radiation protection and in optimizing therapeutic gain during radiotherapy.

  17. Marketing defibrillation training programs and bystander intervention support.

    Science.gov (United States)

    Sneath, Julie Z; Lacey, Russell

    2009-01-01

    This exploratory study identifies perceptions of and participation in resuscitation training programs, and bystanders' willingness to resuscitate cardiac arrest victims. While most of the study's participants greatly appreciate the importance of saving someone's life, many indicated that they did not feel comfortable assuming this role. The findings also demonstrate there is a relationship between type of victim and bystanders' willingness to intervene. Yet, bystander intervention discomfort can be overcome with cardiopulmonary resuscitation and defibrillation training, particularly when the victim is a coworker or stranger. Further implications of these findings are discussed and modifications to public access defibrillation (PAD) training programs' strategy and communications are proposed.

  18. Genome modifications in plant cells by custom-made restriction enzymes.

    Science.gov (United States)

    Tzfira, Tzvi; Weinthal, Dan; Marton, Ira; Zeevi, Vardit; Zuker, Amir; Vainstein, Alexander

    2012-05-01

    Genome editing, i.e. the ability to mutagenize, insert, delete and replace sequences, in living cells is a powerful and highly desirable method that could potentially revolutionize plant basic research and applied biotechnology. Indeed, various research groups from academia and industry are in a race to devise methods and develop tools that will enable not only site-specific mutagenesis but also controlled foreign DNA integration and replacement of native and transgene sequences by foreign DNA, in living plant cells. In recent years, much of the progress seen in gene targeting in plant cells has been attributed to the development of zinc finger nucleases and other novel restriction enzymes for use as molecular DNA scissors. The induction of double-strand breaks at specific genomic locations by zinc finger nucleases and other novel restriction enzymes results in a wide variety of genetic changes, which range from gene addition to the replacement, deletion and site-specific mutagenesis of endogenous and heterologous genes in living plant cells. In this review, we discuss the principles and tools for restriction enzyme-mediated gene targeting in plant cells, as well as their current and prospective use for gene targeting in model and crop plants.

  19. CD1d-restricted peripheral T cell lymphoma in mice and humans

    Science.gov (United States)

    Bachy, Emmanuel; Urb, Mirjam; Chandra, Shilpi; Robinot, Rémy; Bricard, Gabriel; de Bernard, Simon; Traverse-Glehen, Alexandra; Gazzo, Sophie; Blond, Olivier; Khurana, Archana; Baseggio, Lucile; Heavican, Tayla; Ffrench, Martine; Crispatzu, Giuliano; Mondière, Paul; Schrader, Alexandra; Taillardet, Morgan; Thaunat, Olivier; Martin, Nadine; Dalle, Stéphane; Le Garff-Tavernier, Magali; Salles, Gilles; Lachuer, Joel; Hermine, Olivier; Asnafi, Vahid; Roussel, Mikael; Lamy, Thierry; Herling, Marco; Iqbal, Javeed; Buffat, Laurent; Marche, Patrice N.; Gaulard, Philippe; Kronenberg, Mitchell; Defrance, Thierry

    2016-01-01

    Peripheral T cell lymphomas (PTCLs) are a heterogeneous entity of neoplasms with poor prognosis, lack of effective therapies, and a largely unknown pathophysiology. Identifying the mechanism of lymphomagenesis and cell-of-origin from which PTCLs arise is crucial for the development of efficient treatment strategies. In addition to the well-described thymic lymphomas, we found that p53-deficient mice also developed mature PTCLs that did not originate from conventional T cells but from CD1d-restricted NKT cells. PTCLs showed phenotypic features of activated NKT cells, such as PD-1 up-regulation and loss of NK1.1 expression. Injections of heat-killed Streptococcus pneumonia, known to express glycolipid antigens activating NKT cells, increased the incidence of these PTCLs, whereas Escherichia coli injection did not. Gene expression profile analyses indicated a significant down-regulation of genes in the TCR signaling pathway in PTCL, a common feature of chronically activated T cells. Targeting TCR signaling pathway in lymphoma cells, either with cyclosporine A or anti-CD1d blocking antibody, prolonged mice survival. Importantly, we identified human CD1d-restricted lymphoma cells within Vδ1 TCR-expressing PTCL. These results define a new subtype of PTCL and pave the way for the development of blocking anti-CD1d antibody for therapeutic purposes in humans. PMID:27069116

  20. From Agrobacterium to viral vectors: genome modification of plant cells by rare cutting restriction enzymes.

    Science.gov (United States)

    Marton, Ira; Honig, Arik; Omid, Ayelet; De Costa, Noam; Marhevka, Elena; Cohen, Barry; Zuker, Amir; Vainstein, Alexander

    2013-01-01

    Researchers and biotechnologists require methods to accurately modify the genome of higher eukaryotic cells. Such modifications include, but are not limited to, site-specific mutagenesis, site-specific insertion of foreign DNA, and replacement and deletion of native sequences. Accurate genome modifications in plant species have been rather limited, with only a handful of plant species and genes being modified through the use of early genome-editing techniques. The development of rare-cutting restriction enzymes as a tool for the induction of site-specific genomic double-strand breaks and their introduction as a reliable tool for genome modification in animals, animal cells and human cell lines have paved the way for the adaptation of rare-cutting restriction enzymes to genome editing in plant cells. Indeed, the number of plant species and genes which have been successfully edited using zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and engineered homing endonucleases is on the rise. In our review, we discuss the basics of rare-cutting restriction enzyme-mediated genome-editing technology with an emphasis on its application in plant species.

  1. A20 restricts wnt signaling in intestinal epithelial cells and suppresses colon carcinogenesis.

    Directory of Open Access Journals (Sweden)

    Ling Shao

    Full Text Available Colon carcinogenesis consists of a multistep process during which a series of genetic and epigenetic adaptations occur that lead to malignant transformation. Here, we have studied the role of A20 (also known as TNFAIP3, a ubiquitin-editing enzyme that restricts NFκB and cell death signaling, in intestinal homeostasis and tumorigenesis. We have found that A20 expression is consistently reduced in human colonic adenomas than in normal colonic tissues. To further investigate A20's potential roles in regulating colon carcinogenesis, we have generated mice lacking A20 specifically in intestinal epithelial cells and interbred these with mice harboring a mutation in the adenomatous polyposis coli gene (APC(min. While A20(FL/FL villin-Cre mice exhibit uninflamed intestines without polyps, A20(FL/FL villin-Cre APC(min/+ mice contain far greater numbers and larger colonic polyps than control APC(min mice. We find that A20 binds to the β-catenin destruction complex and restricts canonical wnt signaling by supporting ubiquitination and degradation of β-catenin in intestinal epithelial cells. Moreover, acute deletion of A20 from intestinal epithelial cells in vivo leads to enhanced expression of the β-catenin dependent genes cyclinD1 and c-myc, known promoters of colon cancer. Taken together, these findings demonstrate new roles for A20 in restricting β-catenin signaling and preventing colon tumorigenesis.

  2. Glial-restricted precursors as potential candidates for ALS cell-replacement therapy.

    Science.gov (United States)

    Kruminis-Kaszkiel, Ewa; Wojtkiewicz, Joanna; Maksymowicz, Wojciech

    2014-01-01

    Amyotrophic lateral sclerosis is a multifactorial progressive neurodegenerative disorder leading to severe disability and death within 3-5 years after diagnosis. The main mechanisms underlying the disease progression are poorly known but according to the current knowledge, neuroinflammation is a key player in motor neurons damage. Astrocytes constitute an important cell population involved in neuroinflammatory reaction. Many studies confirmed their striking connection with motor neuron pathology and therefore they might be a target for the treatment of ALS. Cell-based therapy appears to be a promising strategy. Since direct replacement or restoring of motor neurons using various stem cells is challenging, enrichment of healthy donor-derived astrocytes appears to be a more realistic and beneficial approach. The effects of astrocytes have been examined using transplantation of glial-restricted precursors (GRPs) that represent one of the earliest precursors within the oligodendrocytic and astrocytic cell lineage. In this review, we focused on evidence-based data on astrocyte replacement transplantation therapy using GRPs in animal models of motor neuron diseases. The efficacy of GRPs engrafting is very encouraging. Furthermore, the lesson learned from application of lineage-restricted precursors in spinal cord injury (SCI) indicates that differentiation of GRPs into astrocytes before transplantation might be more advantageous in the context of axon regeneration. To sum up, the studies of glial-restricted precursors have made a step forward to ALS research and might bring breakthroughs to the field of ALS therapy in the future.

  3. Evidence for a critical role of gene occlusion in cell fate restriction

    Institute of Scientific and Technical Information of China (English)

    Jedidiah Gaetz; Wei-Hua Yu; Andy Peng Xiang; Bruce T Lahn; Kayla L Clift; Croydon J Fernandes; Frank Fuxiang Mao; Jae Hyun Lee; Li Zhang; Samuel W Baker; Timothy J Looney; Kara M Foshay

    2012-01-01

    The progressive restriction of cell fate during lineage differentiation is a poorly understood phenomenon despite its ubiquity in multicellular organisms.We recently used a cell fusion assay to define a mode of epigenetic silencing that we termed "occlusion",wherein affected genes are silenced by cis-acting chromatin mechanisms irrespective of whether trans-acting transcriptional activators are present.We hypothesized that occlusion of lineage-inappropriate genes could contribute to cell fate restriction.Here,we test this hypothesis by introducing bacterial artificial chromosomes (BACs),which are devoid of chromatin modifications necessary for occlusion,into mouse fibroblasts.We found that BAC transgenes corresponding to occluded endogenous genes are expressed in most eases,whereas BAC transgenes corresponding to silent but non-occluded endogenous genes are not expressed.This indicates that the cellular milieu in trans supports the expression of most occluded genes in fibroblasts,and that the silent state of these genes is solely the consequence of occlusion in cis.For the BAC corresponding to the occluded myogenic master regulator Myf5,expression of the Myf5 transgene on the BAC triggered fibroblasts to acquire a muscle-like phenotype.These results provide compelling evidence for a critical role of gene occlusion in cell fate restriction.

  4. RESTRICTION ENDONUCLEASE ANALYSIS OF MITOCHONDRIAL DNA FROM HUMAN LUNG ADENOCARCINOMA CELL LINE SPC-A-1

    Institute of Scientific and Technical Information of China (English)

    HU Yide; QIAN Guisheng; CHEN Weizhong; LI Shuping; WANG Guansong; MAO Baoling

    1999-01-01

    Objective: To understand the role of mitochondrial DNA (mtDNA) in carcinogenesis. Methods: single-step method was used to isolate the mtDNA from human lung adenocarcinoma cell line SPC-A-1. The mtDNA was analyzed by restriction fragment length polymorphism (RFLP) with 11 kinds of restriction endonuclease, which were Pvu Ⅱ, Xho Ⅰ, Pst Ⅰ, EcoR Ⅰ,BstE Ⅱ, Hind Ⅲ, Hpa Ⅰ, Bcl Ⅰ, EcoR Ⅴ, Sca Ⅰ and Xba Ⅰ.Restriction map of mtDNA from SPC-A-1 cell was obtained by the single and double-digestion method.Results: It was found that no variation at 32 restrictionsites could be detected in the coding region of mtDNA from SPC-A-1 cell line. But a new site was found at nucleotide 16276 (EcoR Ⅴ) within the noncoding region.Conclusion: These results indicate that the primary structure of gene coding region of mtDNA isolated from SPC-A-1 cell is highly stable. While the major variation of nucleotide is probably located in the noncoding region.

  5. Modulation of modeled microgravity on radiation-induced bystander effects in Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ting [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Sun, Qiao [Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); Xu, Wei; Li, Fanghua [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Li, Huasheng; Lu, Jinying [Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); Wu, Lijun; Wu, Yuejin [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Liu, Min [Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); Bian, Po [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China)

    2015-03-15

    Highlights: • The effects of microgravity on the radiation-induced bystander effects (RIBE) were definitely demonstrated. • The effects of microgravity on RIBE might be divergent for different biological events. • The microgravity mainly modified the generation or transport of bystander signals at early stage. - Abstract: Both space radiation and microgravity have been demonstrated to have inevitable impact on living organisms during space flights and should be considered as important factors for estimating the potential health risk for astronauts. Therefore, the question whether radiation effects could be modulated by microgravity is an important aspect in such risk evaluation. Space particles at low dose and fluence rate, directly affect only a fraction of cells in the whole organism, which implement radiation-induced bystander effects (RIBE) in cellular response to space radiation exposure. The fact that all of the RIBE experiments are carried out in a normal gravity condition bring forward the need for evidence regarding the effect of microgravity on RIBE. In the present study, a two-dimensional rotation clinostat was adopted to demonstrate RIBE in microgravity conditions, in which the RIBE was assayed using an experimental system of root-localized irradiation of Arabidopsis thaliana (A. thaliana) plants. The results showed that the modeled microgravity inhibited significantly the RIBE-mediated up-regulation of expression of the AtRAD54 and AtRAD51 genes, generation of reactive oxygen species (ROS) and transcriptional activation of multicopy P35S:GUS, but made no difference to the induction of homologous recombination by RIBE, showing divergent responses of RIBE to the microgravity conditions. The time course of interaction between the modeled microgravity and RIBE was further investigated, and the results showed that the microgravity mainly modulated the processes of the generation or translocation of the bystander signal(s) in roots.

  6. Thymic anlage is colonized by progenitors restricted to T, NK, and dendritic cell lineages.

    Science.gov (United States)

    Masuda, Kyoko; Itoi, Manami; Amagai, Takashi; Minato, Nagahiro; Katsura, Yoshimoto; Kawamoto, Hiroshi

    2005-03-01

    It remains controversial whether the thymus-colonizing progenitors are committed to the T cell lineage. A major problem that has impeded the characterization of thymic immigrants has been that the earliest intrathymic progenitors thus far identified do not necessarily represent the genuine thymic immigrants, because their developmental potential should have been influenced by contact with the thymic microenvironment. In the present study, we examined the developmental potential of the ontogenically earliest thymic progenitors of day 11 murine fetus. These cells reside in the surrounding mesenchymal region and have not encountered thymic epithelial components. Flow cytometric and immunohistochemical analyses demonstrated that these cells are exclusively Lin(-)c-kit(+)IL-7R(+). Limiting dilution analyses disclosed that the progenitors with T cell potential were abundant, while those with B cell potential were virtually absent in the region of day 11 thymic anlage. Clonal analyses reveled that they are restricted to T, NK, and dendritic cell lineages. Each progenitor was capable of forming a large number of precursors that may clonally accommodate highly diverse TCRbeta chains. These results provide direct evidence that the progenitors restricted to the T/NK/dendritic cell lineage selectively immigrate into the thymus.

  7. Photon hormesis deactivates alpha-particle induced bystander effects between zebrafish embryos

    Science.gov (United States)

    Ng, C. Y. P.; Cheng, S. H.; Yu, K. N.

    2017-04-01

    In the present work, we studied the effects of low-dose X-ray photons on the alpha-particle induced bystander effects between embryos of the zebrafish, Danio rerio. The effects on the naive whole embryos were studied through quantification of apoptotic signals (amounts of cells undergoing apoptosis) at 24 h post fertilization (hpf) using vital dye acridine orange staining, followed by counting the stained cells under a fluorescent microscope. We report data showing that embryos at 5 hpf subjected to a 4.4 mGy alpha-particle irradiation could release a stress signal into the medium, which could induce bystander effect in partnered naive embryos sharing the same medium. We also report that the bystander effect was deactivated when the irradiated embryos were subjected to a concomitant irradiation of 10 or 14 mGy of X-rays, but no such deactivation was achieved if the concomitant X-ray dose dropped to 2.5 or 5 mGy. In the present study, the significant drop in the amount of apoptotic signals on the embryos having received 4.4 mGy alpha particles together X-rays irradiation from 2.5 or 5 mGy to 10 or 14 mGy, together with the deactivation of RIBE with concomitant irradiation of 10 or 14 mGy of X-rays supported the participation of photon hormesis with an onset dose between 5 and 10 mGy, which might lead to removal of aberrant cells through early apoptosis or induction of high-fidelity DNA repair. As we found that photons and alpha particles could have opposite biological effects when these were simultaneously irradiated onto living organisms, these ionizing radiations could be viewed as two different environmental stressors, and the resultant effects could be regarded as multiple stressor effects. The present work presented the first study on a multiple stressor effect which occurred on bystander organisms. In other words, this was a non-targeted multiple stressor effect. The photon hormesis could also explain some failed attempts to observe neutron-induced bystander

  8. Radiation-induced genomic instability and bystander effects: implications for radiation protection; Instabilite genomique et effet ''bystander'' induit par les rayonnements ionisants: implications pour la radioprotection

    Energy Technology Data Exchange (ETDEWEB)

    Little, J.B. [Harvard School of Public Health, Lab. of Radiobiology, Boston, MA (United States)

    2002-09-01

    Evidence has emerged over the past decade for the existence of two cellular phenomenons which challenge the standard paradigms for the induction of biological effects by ionizing radiation. In both cases, important genetic changes arise in cells that in themselves receive no radiation exposure. In the first, radiation induces a type of transmissible genomic instability in cells that leads to a persistent enhancement in the rate at which genetic alterations including mutations and chromosomal aberrations arise in the descendants of the original irradiated cell after many generations of replication. In the bystander effect, damage signals are transmitted from irradiated to non-irradiated cells in the population, leading to the occurrence of biologic effects in these 'bystander' cells. In this review, our current knowledge concerning these two phenomena is described and their potential impact on the estimation of risks of low level radiation exposure discussed. (author)

  9. Demonstration of a novel HIV-1 restriction phenotype from a human T cell line.

    Directory of Open Access Journals (Sweden)

    Yanxing Han

    Full Text Available BACKGROUND: Although retroviruses may invade host cells, a productive infection can be established only after the virus counteracts inhibition from different types of host restriction factors. Fv1, APOBEC3G/F, TRIM5alpha, ZAP, and CD317 inhibit the replication of different retroviruses by interfering with viral uncoating, reverse transcription, nuclear import, RNA stability, and release. In humans, although APOBEC3G/3F and CD317 block HIV-1 replication, their antiviral activities are neutralized by viral proteins Vif and Vpu. So far, no human gene has been found to effectively block wild type HIV-1 replication under natural condition. Thus, identification of such a gene product would be of great medical importance for the development of HIV therapies. METHOD AND FINDINGS: In this study, we discovered a new type of host restriction against the wild type HIV-1 from a CD4/CXCR4 double-positive human T cell line. We identified a CEM-derived cell line (CEM.NKR that is highly resistant to productive HIV-1 infection. Viral production was reduced by at least 1000-fold when compared to the other permissive human T cell lines such as H9, A3.01, and CEM-T4. Importantly, this resistance was evident at extremely high multiplicity of infection. Further analyses demonstrated that HIV-1 could finish the first round of replication in CEM.NKR cells, but the released virions were poorly infectious. These virions could enter the target cells, but failed to initiate reverse transcription. Notably, this restriction phenotype was also present in CEM.NKR and 293T heterokaryons. CONCLUSIONS: These results clearly indicate that CEM.NKR cells express a HIV inhibitory gene(s. Further characterization of this novel gene product(s will reveal a new antiretroviral mechanism that directly inactivates wild type HIV-1.

  10. Distinct cell stress responses induced by ATP restriction in quiescent human fibroblasts

    Directory of Open Access Journals (Sweden)

    Nirupama Yalamanchili

    2016-10-01

    Full Text Available Quiescence is the prevailing state of many cell types under homeostatic conditions. Yet, surprisingly little is known about how quiescent cells respond to energetic and metabolic challenges. To better understand compensatory responses of quiescent cells to metabolic stress, we established, in human primary dermal fibroblasts, an experimental ‘energy restriction’ model. Quiescence was achieved by short-term culture in serum-deprived media and ATP supply restricted using a combination of glucose transport inhibitors and mitochondrial uncouplers. In aggregate, these measures led to markedly reduced intracellular ATP levels while not compromising cell viability over the observation period of 48 h. Analysis of the transcription factor landscape induced by this treatment revealed alterations in several signal transduction nodes beyond the expected biosynthetic adaptations. These included increased abundance of NF-κB regulated transcription factors and altered transcription factor subsets regulated by Akt and p53. The observed changes in gene regulation and corresponding alterations in key signaling nodes are likely to contribute to cell survival at intracellular ATP concentrations substantially below those achieved by growth factor deprivation alone. This experimental model provides a benchmark for the investigation of cell survival pathways and related molecular targets that are associated with restricted energy supply associated with biological aging and metabolic diseases.

  11. SirT1 knockdown potentiates radiation-induced bystander effect through promoting c-Myc activity and thus facilitating ROS accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yuexia [Institute of Radiation Medicine, Fudan University, Shanghai (China); Central Laboratory, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai (China); Tu, Wenzhi; Zhang, Jianghong; He, Mingyuan; Ye, Shuang; Dong, Chen [Institute of Radiation Medicine, Fudan University, Shanghai (China); Shao, Chunlin, E-mail: clshao@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, Shanghai (China)

    2015-02-15

    Highlights: • γ-Irradiation induced bystander effects between hepatoma cells and hepatocyte cells. • SirT1 played a protective role in regulating this bystander effect. • SirT1 contributed to the protective effects via elimination the accumulation of ROS. • The activity of c-Myc is critical for maintaining the protective role of SirT1. - Abstract: Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the bystander signaling processes, especially under hypoxic condition, are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 and SK-Hep-1 cells under either normoxia or hypoxia. This bystander response was dramatically diminished or enhanced when the SirT1 gene of irradiated hepatoma cells was overexpressed or knocked down, respectively, especially under hypoxia. Meanwhile, SirT1 knockdown promoted transcriptional activity for c-Myc and facilitated ROS accumulation. But both of the increased bystander responses and ROS generation due to SirT1-knockdown were almost completely suppressed by c-Myc interference. Moreover, ROS scavenger effectively abolished the RIBE triggered by irradiated hepatoma cells even with SirT1 depletion. These findings provide new insights that SirT1 has a profound role in regulating RIBE where a c-Myc-dependent release of ROS may be involved.

  12. Identification of genes that are essential to restrict genome duplication to once per cell division

    Science.gov (United States)

    Vassilev, Alex; Lee, Chrissie Y.; Vassilev, Boris; Zhu, Wenge; Ormanoglu, Pinar; Martin, Scott E.; DePamphilis, Melvin L.

    2016-01-01

    Nuclear genome duplication is normally restricted to once per cell division, but aberrant events that allow excess DNA replication (EDR) promote genomic instability and aneuploidy, both of which are characteristics of cancer development. Here we provide the first comprehensive identification of genes that are essential to restrict genome duplication to once per cell division. An siRNA library of 21,584 human genes was screened for those that prevent EDR in cancer cells with undetectable chromosomal instability. Candidates were validated by testing multiple siRNAs and chemical inhibitors on both TP53+ and TP53- cells to reveal the relevance of this ubiquitous tumor suppressor to preventing EDR, and in the presence of an apoptosis inhibitor to reveal the full extent of EDR. The results revealed 42 genes that prevented either DNA re-replication or unscheduled endoreplication. All of them participate in one or more of eight cell cycle events. Seventeen of them have not been identified previously in this capacity. Remarkably, 14 of the 42 genes have been shown to prevent aneuploidy in mice. Moreover, suppressing a gene that prevents EDR increased the ability of the chemotherapeutic drug Paclitaxel to induce EDR, suggesting new opportunities for synthetic lethalities in the treatment of human cancers. PMID:27144335

  13. CD8+ T cells specific for the islet autoantigen IGRP are restricted in their T cell receptor chain usage

    Science.gov (United States)

    Fuchs, Yannick F.; Eugster, Anne; Dietz, Sevina; Sebelefsky, Christian; Kühn, Denise; Wilhelm, Carmen; Lindner, Annett; Gavrisan, Anita; Knoop, Jan; Dahl, Andreas; Ziegler, Anette-G.; Bonifacio, Ezio

    2017-01-01

    CD8+ T cells directed against beta cell autoantigens are considered relevant for the pathogenesis of type 1 diabetes. Using single cell T cell receptor sequencing of CD8+ T cells specific for the IGRP265-273 epitope, we examined whether there was expansion of clonotypes and sharing of T cell receptor chains in autoreactive CD8+ T cell repertoires. HLA-A*0201 positive type 1 diabetes patients (n = 19) and controls (n = 18) were analysed. TCR α- and β-chain sequences of 418 patient-derived IGRP265-273-multimer+ CD8+ T cells representing 48 clonotypes were obtained. Expanded populations of IGRP265-273-specific CD8+ T cells with dominant clonotypes that had TCR α-chains shared across patients were observed. The SGGSNYKLTF motif corresponding to TRAJ53 was contained in 384 (91.9%) cells, and in 20 (41.7%) patient-derived clonotypes. TRAJ53 together with TRAV29/DV5 was found in 15 (31.3%) clonotypes. Using next generation TCR α-chain sequencing, we found enrichment of one of these TCR α-chains in the memory CD8+ T cells of patients as compared to healthy controls. CD8+ T cell clones bearing the enriched motifs mediated antigen-specific target cell lysis. We provide the first evidence for restriction of T cell receptor motifs in the alpha chain of human CD8+ T cells with specificity to a beta cell antigen. PMID:28300170

  14. Increased iron export by ferroportin induces restriction of HIV-1 infection in sickle cell disease

    Science.gov (United States)

    Kumari, Namita; Ammosova, Tatiana; Diaz, Sharmin; Lin, Xionghao; Niu, Xiaomei; Ivanov, Andrey; Jerebtsova, Marina; Dhawan, Subhash; Oneal, Patricia; Nekhai, Sergei

    2017-01-01

    The low incidence of HIV-1 infection in patients with sickle cell disease (SCD) and inhibition of HIV-1 replication in vitro under the conditions of low intracellular iron or heme treatment suggests a potential restriction of HIV-1 infection in SCD. We investigated HIV-1 ex vivo infection of SCD peripheral blood mononuclear cells (PBMCs) and found that HIV-1 replication was inhibited at the level of reverse transcription (RT) and transcription. We observed increased expression of heme and iron-regulated genes, previously shown to inhibit HIV-1, including ferroportin, IKBα, HO-1, p21, and SAM domain and HD domain-containing protein 1 (SAMHD1). HIV-1 inhibition was less pronounced in hepcidin-treated SCD PBMCs and more pronounced in the iron or iron chelators treated, suggesting a key role of iron metabolism. In SCD PBMCs, labile iron levels were reduced and protein levels of ferroportin, HIF-1α, IKBα, and HO-1 were increased. Hemin treatment induced ferroportin expression and inhibited HIV-1 in THP-1 cells, mimicking the HIV-1 inhibition in SCD PBMCs, especially as hepcidin similarly prevented HIV-1 inhibition. In THP-1 cells with knocked down ferroportin, IKBα, or HO-1 genes but not HIF-1α or p21, HIV-1 was not inhibited by hemin. Activity of SAMHD1-regulatory CDK2 was decreased, and SAMHD1 phosphorylation was reduced in SCD PBMCs and hemin-treated THP-1 cells, suggesting SAMHD1-mediated HIV-1 restriction in SCD. Our findings point to ferroportin as a trigger of HIV-1 restriction in SCD settings, linking reduced intracellular iron levels to the inhibition of CDK2 activity, reduction of SAMHD1 phosphorylation, increased IKBα expression, and inhibition of HIV-1 RT and transcription.

  15. TNFAIP3 promotes survival of CD4 T cells by restricting MTOR and promoting autophagy.

    Science.gov (United States)

    Matsuzawa, Yu; Oshima, Shigeru; Takahara, Masahiro; Maeyashiki, Chiaki; Nemoto, Yasuhiro; Kobayashi, Masanori; Nibe, Yoichi; Nozaki, Kengo; Nagaishi, Takashi; Okamoto, Ryuichi; Tsuchiya, Kiichiro; Nakamura, Tetsuya; Ma, Averil; Watanabe, Mamoru

    2015-01-01

    Autophagy plays important roles in metabolism, differentiation, and survival in T cells. TNFAIP3/A20 is a ubiquitin-editing enzyme that is thought to be a negative regulator of autophagy in cell lines. However, the role of TNFAIP3 in autophagy remains unclear. To determine whether TNFAIP3 regulates autophagy in CD4 T cells, we first analyzed Tnfaip3-deficient naïve CD4 T cells in vitro. We demonstrated that Tnfaip3-deficient CD4 T cells exhibited reduced MAP1LC3/LC3 (microtubule-associated protein 1 light chain 3) puncta formation, increased mitochondrial content, and exaggerated reactive oxygen species (ROS) production. These results indicate that TNFAIP3 promotes autophagy after T cell receptor (TCR) stimulation in CD4 T cells. We then investigated the mechanism by which TNFAIP3 promotes autophagy signaling. We found that TNFAIP3 bound to the MTOR (mechanistic target of rapamycin) complex and that Tnfaip3-deficient cells displayed enhanced ubiquitination of the MTOR complex and MTOR activity. To confirm the effects of enhanced MTOR activity in Tnfaip3-deficient cells, we analyzed cell survival following treatment with Torin1, an MTOR inhibitor. Tnfaip3-deficient CD4 T cells exhibited fewer cell numbers than the control cells in vitro and in vivo. In addition, the impaired survival of Tnfaip3-deficient cells was ameliorated with Torin1 treatment in vitro and in vivo. The effect of Torin1 was abolished by Atg5 deficiency. Thus, enhanced MTOR activity regulates the survival of Tnfaip3-deficient CD4 T cells. Taken together, our findings illustrate that TNFAIP3 restricts MTOR signaling and promotes autophagy, providing new insight into the manner in which MTOR and autophagy regulate survival in CD4 T cells.

  16. Exogenous DNA internalisation by sperm cells is improved by combining lipofection and restriction enzyme mediated integration.

    Science.gov (United States)

    Churchil, R R; Gupta, J; Singh, A; Sharma, D

    2011-06-01

    1. Three types of exogenous DNA inserts, i.e. complete linearised pVIVO2-GFP/LacZ vector (9620 bp), the LacZ gene (5317 bp) and the GFP gene (2152 bp) were used to transfect chicken spermatozoa through simple incubation of sperm cells with insert. 2. PCR assay, Dot Blot hybridisation and Southern hybridisation showed the successful internalisation of exogenous DNA by chicken sperm cells. 3. Lipofection and Restriction Enzyme Mediated Integration (REMI) were used to improve the rate of internalisation of exogenous DNA by sperm cells. 4. Results from dot blot as well as Southern hybridisation were semi-quantified and improved exogenous DNA uptake by sperm cells through lipofection and REMI. Stronger signals were observed from hybridisation of LacZ as well as GFP specific probe with the DNA from lipofected exogenous DNA transfected sperm DNA in comparison with those transfected with nude exogenous DNA.

  17. Monitoring of bystander effect of herpes simplex virus thymidine kinase/acyclovir system using fluorescence resonance energy transfer technique.

    Science.gov (United States)

    Xiong, Tao; Li, Yongjun; Ni, Fenge; Zhang, Feng

    2012-02-01

    Cytotoxic gene therapy mediated by gene transfer of the herpes simplex virus thymidine kinase (HSV-tk) gene followed by acyclovir (ACV) treatment has been reported to inhibit malignant tumor growth in a variety of studies. The magnitude of "bystander effect" is an essential factor for this anti-tumor approach in vivo. However, the mechanism by which HSV-tk/ACV brings "bystander effect" is poorly understood. In this report, the plasmid CD3 (ECFP-CRS-DsRed) and TK-GFP were transferred to the human adenoid cystic carcinoma line ACC-M cell line. The CD3-expressing cells apoptosis was monitored using fluorescence resonance energy transfer (FRET) technique. First, CD3 and TK-GFP co-expressing ACC-M cells apoptosis was monitored using FRET technique. The apoptosis was induced by ACV and initiated by caspase3. The FRET efficient was remarkably decreased and then disappeared during cellular apoptosis, which indicated that the TK-GFP expressing ACC-M cells apoptosis, induced by ACV, was via a caspase3-dependent pathway. Secondly, CD3 and TK-GFP mixed expressing ACC-M cells apoptosis, induced by ACV, were monitored using FRET technique. The apoptotic phenomena appeared in the CD3-expressing ACC-M cells. The results show that HSV-tk/ACV system killed ACC-M cells using its bystander effect. These results confirm that HSV-tk/ACV system is potential for cancer gene therapy.

  18. Recursive mentalizing and common knowledge in the bystander effect.

    Science.gov (United States)

    Thomas, Kyle A; De Freitas, Julian; DeScioli, Peter; Pinker, Steven

    2016-05-01

    The more potential helpers there are, the less likely any individual is to help. A traditional explanation for this bystander effect is that responsibility diffuses across the multiple bystanders, diluting the responsibility of each. We investigate an alternative, which combines the volunteer's dilemma (each bystander is best off if another responds) with recursive theory of mind (each infers what the others know about what he knows) to predict that actors will strategically shirk when they think others feel compelled to help. In 3 experiments, participants responded to a (fictional) person who needed help from at least 1 volunteer. Participants were in groups of 2 or 5 and had varying information about whether other group members knew that help was needed. As predicted, people's decision to help zigzagged with the depth of their asymmetric, recursive knowledge (e.g., "John knows that Michael knows that John knows help is needed"), and replicated the classic bystander effect when they had common knowledge (everyone knowing what everyone knows). The results demonstrate that the bystander effect may result not from a mere diffusion of responsibility but specifically from actors' strategic computations.

  19. Factors that restrict the intestinal cell permeation of cyclic prodrugs of an opioid peptide (DADLE)

    DEFF Research Database (Denmark)

    Ouyang, Hui; Chen, Weiqing; Andersen, Thomas E;

    2009-01-01

    inactive or substantially less active than PSC-833 in increasing the P(B) values of these prodrugs. These data suggest that, while P-gp plays a role, other factors (e.g., substrate activity for other efflux transporters and/or for metabolic enzymes) may contribute to restricting the permeation of AOA......The objective of this study was to elucidate the role of P-glycoprotein (P-gp) in restricting the intestinal mucosal permeation of cyclic prodrugs (AOA-DADLE, CA-DADLE, and OMCA-DADLE) of the opioid peptide DADLE (H-Tyr-D-Ala-Gly-Phe-D-Leu-OH). In the Caco-2 cell model, the high P......(app,BL-to-AP)/P(app,AP-to-BL) ratios of AOA-DADLE, CA-DADLE, and OMCA-DADLE (71-117) were significantly decreased by including known P-gp inhibitors, GF-12098, cyclosporine (CyA), or PSC-833, in the incubation media, suggesting that P-gp is restricting the AP-to-BL permeation of these cyclic prodrugs. In the in situ perfused rat...

  20. EphrinB3 restricts endogenous neural stem cell migration after traumatic brain injury.

    Science.gov (United States)

    Dixon, Kirsty J; Mier, Jose; Gajavelli, Shyam; Turbic, Alisa; Bullock, Ross; Turnley, Ann M; Liebl, Daniel J

    2016-11-01

    Traumatic brain injury (TBI) leads to a series of pathological events that can have profound influences on motor, sensory and cognitive functions. Conversely, TBI can also stimulate neural stem/progenitor cell proliferation leading to increased numbers of neuroblasts migrating outside their restrictive neurogenic zone to areas of damage in support of tissue integrity. Unfortunately, the factors that regulate migration are poorly understood. Here, we examine whether ephrinB3 functions to restrict neuroblasts from migrating outside the subventricular zone (SVZ) and rostral migratory stream (RMS). We have previously shown that ephrinB3 is expressed in tissues surrounding these regions, including the overlying corpus callosum (CC), and is reduced after controlled cortical impact (CCI) injury. Our current study takes advantage of ephrinB3 knockout mice to examine the influences of ephrinB3 on neuroblast migration into CC and cortex tissues after CCI injury. Both injury and/or ephrinB3 deficiency led to increased neuroblast numbers and enhanced migration outside the SVZ/RMS zones. Application of soluble ephrinB3-Fc molecules reduced neuroblast migration into the CC after injury and limited neuroblast chain migration in cultured SVZ explants. Our findings suggest that ephrinB3 expression in tissues surrounding neurogenic regions functions to restrict neuroblast migration outside the RMS by limiting chain migration.

  1. Multiple tissue-specific isoforms of sulfatide activate CD1d-restricted type II NKT cells

    DEFF Research Database (Denmark)

    Blomqvist, Maria; Rhost, Sara; Teneberg, Susann;

    2009-01-01

    The glycosphingolipid sulfatide (SO(3)-3Galbeta1Cer) is a demonstrated ligand for a subset of CD1d-restricted NKT cells, which could regulate experimental autoimmune encephalomyelitis, a murine model for multiple sclerosis, as well as tumor immunity and experimental hepatitis. Native sulfatide...... is a mixture of sulfatide isoforms, i.e. sulfatide molecules with different long-chain bases and fatty acid chain lengths and saturation. Here, we demonstrate that sulfatide-specific CD1d-restricted murine NKT hybridomas recognized several different sulfatide isoforms. These included the physiologically...... isoforms by a CD1d-restricted NKT-cell clone, and suggest that sulfatide, a major component of the myelin sheet and pancreatic beta-cells, is one of several natural ligands for type II CD1d-restricted NKT cells....

  2. DMPD: TLR3 in antiviral immunity: key player or bystander? [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16027039 TLR3 in antiviral immunity: key player or bystander? Schroder M, Bowie AG.... Trends Immunol. 2005 Sep;26(9):462-8. (.png) (.svg) (.html) (.csml) Show TLR3 in antiviral immunity: key pl...ayer or bystander? PubmedID 16027039 Title TLR3 in antiviral immunity: key player or bystander? Authors Schr

  3. Promoting Prosocial Behaviors to Prevent Dating Violence among College Students: Evaluation of a Bystander Intervention

    Science.gov (United States)

    Borsky, Amanda E.

    2014-01-01

    The objective of this dissertation was to evaluate a bystander behavior program at the Jefferson College of Health Sciences (JCHS) in Roanoke, Virginia. Specifically, this dissertation examined the: (1) preliminary measurement properties of a newly developed bystander behavior intention scale; (2) impact of the bystander intervention at JCHS; and…

  4. Cell-type-restricted anti-cytokine therapy: TNF inhibition from one pathogenic source.

    Science.gov (United States)

    Efimov, Grigory A; Kruglov, Andrei A; Khlopchatnikova, Zoya V; Rozov, Fedor N; Mokhonov, Vladislav V; Rose-John, Stefan; Scheller, Jürgen; Gordon, Siamon; Stacey, Martin; Drutskaya, Marina S; Tillib, Sergei V; Nedospasov, Sergei A

    2016-03-15

    Overexpression of TNF contributes to pathogenesis of multiple autoimmune diseases, accounting for a remarkable success of anti-TNF therapy. TNF is produced by a variety of cell types, and it can play either a beneficial or a deleterious role. In particular, in autoimmunity pathogenic TNF may be derived from restricted cellular sources. In this study we evaluated the feasibility of cell-type-restricted TNF inhibition in vivo. To this end, we engineered MYSTI (Myeloid-Specific TNF Inhibitor)--a recombinant bispecific antibody that binds to the F4/80 surface molecule on myeloid cells and to human TNF (hTNF). In macrophage cultures derived from TNF humanized mice MYSTI could capture the secreted hTNF, limiting its bioavailability. Additionally, as evaluated in TNF humanized mice, MYSTI was superior to an otherwise analogous systemic TNF inhibitor in protecting mice from lethal LPS/D-Galactosamine-induced hepatotoxicity. Our results suggest a novel and more specific approach to inhibiting TNF in pathologies primarily driven by macrophage-derived TNF.

  5. The VP1u Receptor Restricts Parvovirus B19 Uptake to Permissive Erythroid Cells

    Science.gov (United States)

    Leisi, Remo; Von Nordheim, Marcus; Ros, Carlos; Kempf, Christoph

    2016-01-01

    Parvovirus B19 (B19V) is a small non-enveloped virus and known as the causative agent for the mild childhood disease erythema infectiosum. B19V has an extraordinary narrow tissue tropism, showing only productive infection in erythroid precursor cells in the bone marrow. We recently found that the viral protein 1 unique region (VP1u) contains an N-terminal receptor-binding domain (RBD), which mediates the uptake of the virus into cells of the erythroid lineage. To further investigate the role of the RBD in connection with a B19V-unrelated capsid, we chemically coupled the VP1u of B19V to the bacteriophage MS2 capsid and tested the internalization capacity of the bioconjugate on permissive cells. In comparison, we studied the cellular uptake and infection of B19V along the erythroid differentiation. The results showed that the MS2-VP1u bioconjugate mimicked the specific internalization of the native B19V into erythroid precursor cells, which further coincides with the restricted infection profile. The successful mimicry of B19V uptake demonstrates that the RBD in the VP1u is sufficient for the endocytosis of the viral capsid. Furthermore, the recombinant VP1u competed with B19V uptake into permissive cells, thus excluding a significant alternative uptake mechanism by other receptors. Strikingly, the VP1u receptor appeared to be expressed only on erythropoietin-dependent erythroid differentiation stages that also provide the necessary intracellular factors for a productive infection. Taken together, these findings suggest that the VP1u binds to a yet-unknown erythroid-specific cellular receptor and thus restricts the virus entry to permissive cells. PMID:27690083

  6. Workplace mobbing: How the victim's coping behavior influences bystander responses.

    Science.gov (United States)

    Mulder, Roelie; Bos, Arjan E R; Pouwelse, Mieneke; van Dam, Karen

    2017-01-01

    Victims of workplace mobbing show diverse coping behavior. We investigated the impact of this behavior on bystander cognitions, emotions, and helping toward the victim, integrating coping literature with attribution theory. Adult part-time university students (N = 161) working at various organizations participated in a study with a 3(Coping: approach/avoidance/neutral) × 2(Gender Victim: male/female) × 2(Gender Bystander: male/female) design. Victims showing approach (vs. avoidance) coping were considered to be more self-reliant and less responsible for the continuation of the mobbing, and they elicited less anger. Continuation responsibility and self-reliance mediated the relationship between the victim's coping behavior and bystanders' helping intentions. Female (vs. male) participants reported more sympathy for the victim and greater willingness to help, and female (vs. male) victims elicited less anger. Theoretical and practical implications of the findings are discussed.

  7. Cross-talk between cd1d-restricted nkt cells and γδ cells in t regulatory cell response

    Directory of Open Access Journals (Sweden)

    Huber Sally A

    2011-01-01

    Full Text Available Abstract CD1d is a non-classical major histocompatibility class 1-like molecule which primarily presents either microbial or endogenous glycolipid antigens to T cells involved in innate immunity. Natural killer T (NKT cells and a subpopulation of γδ T cells expressing the Vγ4 T cell receptor (TCR recognize CD1d. NKT and Vγ4 T cells function in the innate immune response via rapid activation subsequent to infection and secrete large quantities of cytokines that both help control infection and modulate the developing adaptive immune response. T regulatory cells represent one cell population impacted by both NKT and Vγ4 T cells. This review discusses the evidence that NKT cells promote T regulatory cell activation both through direct interaction of NKT cell and dendritic cells and through NKT cell secretion of large amounts of TGFβ, IL-10 and IL-2. Recent studies have shown that CD1d-restricted Vγ4 T cells, in contrast to NKT cells, selectively kill T regulatory cells through a caspase-dependent mechanism. Vγ4 T cell elimination of the T regulatory cell population allows activation of autoimmune CD8+ effector cells leading to severe cardiac injury in a coxsackievirus B3 (CVB3 myocarditis model in mice. CD1d-restricted immunity can therefore lead to either immunosuppression or autoimmunity depending upon the type of innate effector dominating during the infection.

  8. MHC CLASS-II-RESTRICTED T-CELL HYBRIDOMAS RECOGNIZING THE NUCLEOCAPSID PROTEIN OF AVIAN CORONAVIUS IBV

    NARCIS (Netherlands)

    BOOTS, AMH; VANLIEROP, MJ; KUSTERS, JG; VANKOOTEN, PJS; VANDERZELIST, BAM; HENSEN, EJ; Boots, Annemieke

    1991-01-01

    Mice were immunized with purified infectious bronchitis virus (IBV), strain M41. Spleen cells, expanded in vitro by stimulation with M41, were immortalized by fusion to obtain T-cell hybridomas, and two major histocompatability complex (MHC) class II (I-E)-restricted T-cell hybridomas were selected

  9. Conflicts targeting epigenetic systems and their resolution by cell death: novel concepts for methyl-specific and other restriction systems.

    Science.gov (United States)

    Ishikawa, Ken; Fukuda, Eri; Kobayashi, Ichizo

    2010-12-01

    Epigenetic modification of genomic DNA by methylation is important for defining the epigenome and the transcriptome in eukaryotes as well as in prokaryotes. In prokaryotes, the DNA methyltransferase genes often vary, are mobile, and are paired with the gene for a restriction enzyme. Decrease in a certain epigenetic methylation may lead to chromosome cleavage by the partner restriction enzyme, leading to eventual cell death. Thus, the pairing of a DNA methyltransferase and a restriction enzyme forces an epigenetic state to be maintained within the genome. Although restriction enzymes were originally discovered for their ability to attack invading DNAs, it may be understood because such DNAs show deviation from this epigenetic status. DNAs with epigenetic methylation, by a methyltransferase linked or unlinked with a restriction enzyme, can also be the target of DNases, such as McrBC of Escherichia coli, which was discovered because of its methyl-specific restriction. McrBC responds to specific genome methylation systems by killing the host bacterial cell through chromosome cleavage. Evolutionary and genomic analysis of McrBC homologues revealed their mobility and wide distribution in prokaryotes similar to restriction-modification systems. These findings support the hypothesis that this family of methyl-specific DNases evolved as mobile elements competing with specific genome methylation systems through host killing. These restriction systems clearly demonstrate the presence of conflicts between epigenetic systems.

  10. Endocytosis restricts Arabidopsis KNOLLE syntaxin to the cell division plane during late cytokinesis.

    Science.gov (United States)

    Boutté, Yohann; Frescatada-Rosa, Márcia; Men, Shuzhen; Chow, Cheung-Ming; Ebine, Kazuo; Gustavsson, Anna; Johansson, Lenore; Ueda, Takashi; Moore, Ian; Jürgens, Gerd; Grebe, Markus

    2010-02-03

    Cytokinesis represents the final stage of eukaryotic cell division during which the cytoplasm becomes partitioned between daughter cells. The process differs to some extent between animal and plant cells, but proteins of the syntaxin family mediate membrane fusion in the plane of cell division in diverse organisms. How syntaxin localization is kept in check remains elusive. Here, we report that localization of the Arabidopsis KNOLLE syntaxin in the plane of cell division is maintained by sterol-dependent endocytosis involving a clathrin- and DYNAMIN-RELATED PROTEIN1A-dependent mechanism. On genetic or pharmacological interference with endocytosis, KNOLLE mis-localizes to lateral plasma membranes after cell-plate fusion. Fluorescence-loss-in-photo-bleaching and fluorescence-recovery-after-photo-bleaching experiments reveal lateral diffusion of GFP-KNOLLE from the plane of division to lateral membranes. In an endocytosis-defective sterol biosynthesis mutant displaying lateral KNOLLE diffusion, KNOLLE secretory trafficking remains unaffected. Thus, restriction of lateral diffusion by endocytosis may serve to maintain specificity of syntaxin localization during late cytokinesis.

  11. Cementum attachment protein manifestation is restricted to the mineralized tissue forming cells of the periodontium

    Energy Technology Data Exchange (ETDEWEB)

    Bar-Kana, I.; Pitaru, S. [Tel Aviv Univ., Dept. of Oral Biology, Goldschleger School of dental Medicine (Israel); Savion, N. [Tel Aviv Univ., Goldschleger Eye Research Inst. (Israel); Narayanan, A.S. [Univ. of Washington, Dept. of Pathology, Faculty of Medicine (United States)

    1998-08-01

    The mechanisms that regulate cementogenesis are mainly unknown. A specific cementum attachment protein (CAP) has been recently partially characterized and found to be more efficient in supporting the attachment of alveolar bone cells (ABC) and periodontal ligament cells (PLC) than that of gingival fibroblasts (GF). The purpose of this study was to determine the capacity of human periodontal-derived cells to bind an express CAP and to relate these properties to their capacity to express alkaline phosphatase (AlP) and form mineralized tissue (MTF). ABC, PLC and GF were tested. Human stromal bone marrow cells (SBMC) and a cementoma-derived cell line (CC) served as controls. CAP binding was determined using {sup 125}I-CAP. The amount of MTF was assessed by alizarin red staining and image analysis determination of the amount of red-stained material. AlP and CAP expression were examined by histochemistry and immuno-chemistry, respectively. The highest expression of CAP was observed in CC, followed by PLC and ABC in decreasing order, whereas SBMC and GF did not express CAP, SBMC manifested the highest CAP binding capacity followed by CC, ABC, PLC and GF. MTF and AlP manifestation were greatest in SBMC, followed by ABC, PLC and CC. Collectively, the results indicate that CAP binding and secretion are not linked and that CAP manifestation is restricted to periodontal derived cell lineages with the potential of forming mineralized tissues. (au) 39 refs.

  12. Fibrocyte-like cells from intrauterine growth restriction placentas have a reduced ability to stimulate angiogenesis.

    Science.gov (United States)

    Riddell, Meghan R; Winkler-Lowen, Bonnie; Jiang, Yanyan; Guilbert, Larry J; Davidge, Sandra T

    2013-09-01

    Intrauterine growth restriction (IUGR) is a common complication of pregnancy whereby the fetus fails to achieve its genetic growth potential. Malformation of the placental vasculature is observed in IUGR and may be due to the development of the placenta in a chronically hypoxic environment. Recently, we identified that the predominant stromal cells in the angiogenic zones of the placenta are fibrocyte-like cells. The conditioned medium from fibrocyte-like cells (FcCM) has been shown to stimulate angiogenesis in vitro. Thus, we hypothesized that FcCM from IUGR cells would have a reduced ability to stimulate angiogenesis and that chronic hypoxia would decrease the ability of both normal and IUGR fibrocyte-like cells to stimulate angiogenesis. IUGR FcCM had a reduced ability to stimulate endothelial tubule-like structure formation and an increased ability to stimulate endothelial migration compared with normal FcCM. However, normal and IUGR FcCM produced in chronic hypoxia did not alter endothelial proliferation, migration, or tubule-like structure formation. IUGR FcCM was found to have reduced levels of the pro-angiogenic cytokine IL-8 and increased levels of the anti-angiogenic factors activin-A and pigment epithelium-derived growth factor. Thus, alterations in the ability of IUGR fibrocyte-like cells to stimulate angiogenesis may contribute to the development of vascular malformation in IUGR, but in vitro these changes cannot be attributed to a chronically hypoxic environment.

  13. Radiation-induced bystander effects and adaptive responses--the Yin and Yang of low dose radiobiology?

    Energy Technology Data Exchange (ETDEWEB)

    Mothersill, Carmel [Medical Physics and Applied Radiation Sciences Unit, McMaster University, Hamilton, Ont., L8S 4K1 (Canada)]. E-mail: mothers@mcmaster.ca; Seymour, Colin [Medical Physics and Applied Radiation Sciences Unit, McMaster University, Hamilton, Ont., L8S 4K1 (Canada)]. E-mail: seymouc@mcmaster.ca

    2004-12-02

    Our current knowledge of the mechanisms underlying the induction of bystander effects by low doses of high or low LET ionizing radiation is reviewed. The question of what actually constitutes a protective effect is discussed in the context of adaptive (often referred to as hormetic or protective) responses. Finally the review considers critically, how bystander effects may be related to observed adaptive responses or other seemingly protective effects of low doses exposures. Bystander effects induce responses at the tissue level, which are similar to generalized stress responses. Most of the work involving low LET radiation exposure discussed in the existing literature measures a death response. Since many cell populations carry damaged cells without being exposed to radiation (so-called 'background damage'), it is possible that low doses exposures cause removal of cells carrying potentially problematic lesions, prior to exposure to radiation. This mechanism could lead to the production of 'U-shaped' or hormetic dose-response curves. The level of adverse, adaptive or apparently beneficial response will be related to the background damage carried by the original cell population, the level of organization at which damage or harm are scored and the precise definition of 'harm'. This model may be important when attempting to predict the consequences of mixed exposures involving low doses of radiation and other environmental stressors.

  14. Escargot Restricts Niche Cell to Stem Cell Conversion in the Drosophila Testis

    Directory of Open Access Journals (Sweden)

    Justin Voog

    2014-05-01

    Full Text Available Stem cells reside within specialized microenvironments, or niches, that control many aspects of stem cell behavior. Somatic hub cells in the Drosophila testis regulate the behavior of cyst stem cells (CySCs and germline stem cells (GSCs and are a primary component of the testis stem cell niche. The shutoff (shof mutation, characterized by premature loss of GSCs and CySCs, was mapped to a locus encoding the evolutionarily conserved transcription factor Escargot (Esg. Hub cells depleted of Esg acquire CySC characteristics and differentiate as cyst cells, resulting in complete loss of hub cells and eventually CySCs and GSCs, similar to the shof mutant phenotype. We identified Esg-interacting proteins and demonstrate an interaction between Esg and the corepressor C-terminal binding protein (CtBP, which was also required for maintenance of hub cell fate. Our results indicate that niche cells can acquire stem cell properties upon removal of a single transcription factor in vivo.

  15. Restricted maternal nutrition alters myogenic regulatory factor expression in satellite cells of ovine offspring.

    Science.gov (United States)

    Raja, J S; Hoffman, M L; Govoni, K E; Zinn, S A; Reed, S A

    2016-07-01

    Poor maternal nutrition inhibits muscle development and postnatal muscle growth. Satellite cells are myogenic precursor cells that contribute to postnatal muscle growth, and their activity can be evaluated by the expression of several transcription factors. Paired-box (Pax)7 is expressed in quiescent and active satellite cells. MyoD is expressed in activated and proliferating satellite cells and myogenin is expressed in terminally differentiating cells. Disruption in the expression pattern or timing of expression of myogenic regulatory factors negatively affects muscle development and growth. We hypothesized that poor maternal nutrition during gestation would alter the in vitro temporal expression of MyoD and myogenin in satellite cells from offspring at birth and 3 months of age. Ewes were fed 100% or 60% of NRC requirements from day 31±1.3 of gestation. Lambs from control-fed (CON) or restricted-fed (RES) ewes were euthanized within 24 h of birth (birth; n=5) or were fed a control diet until 3 months of age (n=5). Satellite cells isolated from the semitendinosus muscle were used for gene expression analysis or cultured for 24, 48 or 72 h and immunostained for Pax7, MyoD or myogenin. Fusion index was calculated from a subset of cells allowed to differentiate. Compared with CON, temporal expression of MyoD and myogenin was altered in cultured satellite cells isolated from RES lambs at birth. The percent of cells expressing MyoD was greater in RES than CON (P=0.03) after 24 h in culture. After 48 h of culture, there was a greater percent of cells expressing myogenin in RES compared with CON (P0.05). In satellite cells from RES lambs at 3 months of age, the percent of cells expressing MyoD and myogenin were greater than CON after 72 h in culture (Psatellite cells of the offspring, which may reduce the pool of myoblasts, decrease myoblast fusion and contribute to the poor postnatal muscle growth previously observed in these animals.

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

    Science.gov (United States)

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

    2009-01-01

    immune response. HCV infection impairs the functioning of these cells (1, 2). However, when clonal expansion of cytotoxic T-lymphocytes (CTLs) is established, the next important restriction for elimination of infected cells is the availability of peptide-MHC class I complexes, which are recognized by CTLs on the surface of target cells (hepatocytes). PMID:19195028

  17. Mechanism of bystander-blaming: defensive attribution, counterfactual thinking, and gender.

    Science.gov (United States)

    Levy, Inna; Ben-David, Sarah

    2015-01-01

    Contemporary victimology recognizes that an understanding of the mechanism of blaming requires a comprehensive approach that includes the victim, the offender, and the bystander. However, most of the existing research on blaming focuses on the victim and the offender, ignoring the issue of bystander-blaming. This study highlights the bystander and investigates bystander-blaming by exploring some theoretical explanations, including counterfactual thinking, defensive attribution, and gender differences. The study included 363 young male and female participants, who read vignettes describing the behavior of the victim and the bystander in a rape scenario and answered questions regarding bystander-blaming. The results show that both counterfactual thinking and defensive attribution play a role in bystander-blaming. This article addresses the theoretical and practical implications of these findings.

  18. The influence of restricted feeding on glucagon-like peptide-1 (GLP-1)-containing cells in the chicken small intestine.

    Science.gov (United States)

    Monir, M M; Hiramatsu, K; Yamasaki, A; Nishimura, K; Watanabe, T

    2014-04-01

    The influence of restricted feeding on the distribution of glucagon-like peptide-1 (GLP-1)-containing endocrine cells in the chicken small intestine was investigated using immunohistochemical and morphometrical techniques. This study demonstrated that the restricted feeding had an influence on the activity of GLP-1-immunoreactive cells in the chicken small intestine. There were differences in the localization and the frequency of occurrence of GLP-1-immunoreactive cells in the small intestine between control and restricted groups, especially 25% feed supply group provided with 25% of the intake during the adapting period. GLP-1-immunoreactive cells in the control chickens were mainly located in epithelium from crypts to the lower part of intestinal villi. Those in restricted groups, however, tended to be located from crypts to the middle part of intestinal villi. The frequency of occurrence of GLP-1-immunoreactive cells was lowest in the control group, medium in 50% feed supply group and highest in 25% feed supply group at each intestinal region examined in this study, that is, increased with the advancement of restricting the amount of feed supply. These data show that the quantity of food intake is one of signals that have an influence on the secretion of GLP-1 from L cells in the chicken small intestine.

  19. SirT1 knockdown potentiates radiation-induced bystander effect through promoting c-Myc activity and thus facilitating ROS accumulation.

    Science.gov (United States)

    Xie, Yuexia; Tu, Wenzhi; Zhang, Jianghong; He, Mingyuan; Ye, Shuang; Dong, Chen; Shao, Chunlin

    2015-02-01

    Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the bystander signaling processes, especially under hypoxic condition, are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 and SK-Hep-1 cells under either normoxia or hypoxia. This bystander response was dramatically diminished or enhanced when the SirT1 gene of irradiated hepatoma cells was overexpressed or knocked down, respectively, especially under hypoxia. Meanwhile, SirT1 knockdown promoted transcriptional activity for c-Myc and facilitated ROS accumulation. But both of the increased bystander responses and ROS generation due to SirT1-knockdown were almost completely suppressed by c-Myc interference. Moreover, ROS scavenger effectively abolished the RIBE triggered by irradiated hepatoma cells even with SirT1 depletion. These findings provide new insights that SirT1 has a profound role in regulating RIBE where a c-Myc-dependent release of ROS may be involved.

  20. Wolbachia restricts insect-specific flavivirus infection in Aedes aegypti cells

    Science.gov (United States)

    Sreenu, Vatipally B.; Mottram, Timothy; McFarlane, Melanie

    2016-01-01

    Mosquito-borne viruses are known to cause disease in humans and livestock and are often difficult to control due to the lack of specific antivirals and vaccines. The Wolbachia endosymbiont has been widely studied for its ability to restrict positive-strand RNA virus infection in mosquitoes, although little is known about the precise antiviral mechanism. In recent years, a variety of insect-specific viruses have been discovered in mosquitoes and an interaction with mosquito-borne viruses has been reported for some of them; however, nothing is known about the effect of Wolbachia on insect-specific virus infection in mosquitoes. Here, we show that transinfection of the Drosophila-derived wMelPop Wolbachia strain into Aedes aegypti-derived cells resulted in inhibition and even clearance of the persistent cell-fusing agent flavivirus infection in these cells. This broadens the antiviral activity of Wolbachia from acute infections to persistent infections and from arboviruses to mosquito-specific viruses. In contrast, no effect on the Phasi Charoen-like bunyavirus persistent infection in these cells was observed, suggesting a difference in Wolbachia inhibition between positive- and negative-strand RNA viruses. PMID:27692043

  1. Caloric restriction promotes cell survival in a mouse model of normal tension glaucoma

    Science.gov (United States)

    Guo, Xiaoli; Kimura, Atsuko; Azuchi, Yuriko; Akiyama, Goichi; Noro, Takahiko; Harada, Chikako; Namekata, Kazuhiko; Harada, Takayuki

    2016-01-01

    Glaucoma is characterized by progressive degeneration of retinal ganglion cells (RGCs) and their axons. We previously reported that loss of glutamate transporters (EAAC1 or GLAST) in mice leads to RGC degeneration that is similar to normal tension glaucoma and these animal models are useful in examining potential therapeutic strategies. Caloric restriction has been reported to increase longevity and has potential benefits in injury and disease. Here we investigated the effects of every-other-day fasting (EODF), a form of caloric restriction, on glaucomatous pathology in EAAC1−/− mice. EODF suppressed RGC death and retinal degeneration without altering intraocular pressure. Moreover, visual impairment was ameliorated with EODF, indicating the functional significance of the neuroprotective effect of EODF. Several mechanisms associated with this neuroprotection were explored. We found that EODF upregulated blood β-hydroxybutyrate levels and increased histone acetylation in the retina. Furthermore, it elevated retinal mRNA expression levels of neurotrophic factors and catalase, whereas it decreased oxidative stress levels in the retina. Our findings suggest that EODF, a safe, non-invasive, and low-cost treatment, may be available for glaucoma therapy. PMID:27669894

  2. HLA-A*0201-restricted CD8+ T-cell epitopes identified in dengue viruses

    Directory of Open Access Journals (Sweden)

    Duan Zhi-Liang

    2012-11-01

    -specific HLA-A*0201-restricted CD8+ T-cell epitopes (NS4a140-148 and NS2a144–152 and one cross-reactive HLA-A*0201-restricted CD8+ T-cell epitopes which is similar to a previously identified epitope were identified in D1V-D4V. Combining prediction algorithms and HLA transgenic mice is an effective strategy to identify HLA-restricted epitopes. Serotype-specific epitopes would be used to determine the protective role of serotype-specific CD8+ T cells, while cross-reactive epitopes may provide assistance in exploring the role of serotype cross-reactive CD8+ T cells in the immunopathogenesis of DHF/DSS.

  3. Incoming College Students' Bystander Behaviors to Prevent Sexual Violence

    Science.gov (United States)

    McMahon, Sarah; Banyard, Victoria L.; McMahon, Sheila M.

    2015-01-01

    Evaluations of bystander intervention education programs demonstrate that this approach results in students' increased willingness to intervene in prosocial ways to prevent sexual violence (e.g., Moynihan, Banyard, Arnold, Eckstein, & Stapleton, 2010). These programs often focus on first-year college students, though theories and research on…

  4. A Qualitative Exploration of Cyber-Bystanders and Moral Engagement

    Science.gov (United States)

    Price, Deborah; Green, Deborah; Spears, Barbara; Scrimgeour, Margaret; Barnes, Alan; Geer, Ruth; Johnson, Bruce

    2014-01-01

    Studies have found that moral disengagement plays a significant role in the continuation of bullying situations (Bonanno, 2005); however, the moral stance of cyber-bystanders--those who witness online bullying--is not yet clear. While research into traditional face-to-face bullying reported that peers would probably or certainly intervene to…

  5. MHC class-I-restricted CD8 T cells play a protective role during primary Salmonella infection.

    Science.gov (United States)

    Lee, Seung-Joo; Dunmire, Samantha; McSorley, Stephen J

    2012-12-17

    Protective immunity against Salmonella infection is known to require CD4 Th1 cells and B cells, but the role of MHC class-I-restricted CD8 T cells is less clear. Previous studies have suggested that CD8 T cells participate in secondary, but not primary, bacterial clearance. However, these studies have used experimental models that are difficult to interpret and do not clearly isolate the role of MHC class-I-restricted CD8 T cells from other cell populations. Here, we examined the role of class-I-restricted T cells in protection against Salmonella infection using mice lacking all classical MHC class-Ia molecules, perforin, or granzyme B. Immunized K(b)D(b)-, perforin-, granzyme B-, or perforin/granzyme B-deficient mice were able to resolve secondary infection with virulent Salmonella, demonstrating that class-I-restricted CTLs are not required for acquired immunity. However, during primary infection with attenuated bacteria, bacterial clearance was delayed in each of these mouse strains when compared to wild-type mice. Taken together, these data demonstrate that CD8 T cells are not required for acquired immunity to Salmonella, but can play a protective role in resolving primary infection with attenuated bacteria.

  6. 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

    2017-01-01

    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. PMID:28262842

  7. MR1-restricted MAIT cells display ligand discrimination and pathogen selectivity through distinct T cell receptor usage.

    Science.gov (United States)

    Gold, Marielle C; McLaren, James E; Reistetter, Joseph A; Smyk-Pearson, Sue; Ladell, Kristin; Swarbrick, Gwendolyn M; Yu, Yik Y L; Hansen, Ted H; Lund, Ole; Nielsen, Morten; Gerritsen, Bram; Kesmir, Can; Miles, John J; Lewinsohn, Deborah A; Price, David A; Lewinsohn, David M

    2014-07-28

    Mucosal-associated invariant T (MAIT) cells express a semi-invariant T cell receptor (TCR) that detects microbial metabolites presented by the nonpolymorphic major histocompatibility complex (MHC)-like molecule MR1. The highly conserved nature of MR1 in conjunction with biased MAIT TCRα chain usage is widely thought to indicate limited ligand presentation and discrimination within a pattern-like recognition system. Here, we evaluated the TCR repertoire of MAIT cells responsive to three classes of microbes. Substantial diversity and heterogeneity were apparent across the functional MAIT cell repertoire as a whole, especially for TCRβ chain sequences. Moreover, different pathogen-specific responses were characterized by distinct TCR usage, both between and within individuals, suggesting that MAIT cell adaptation was a direct consequence of exposure to various exogenous MR1-restricted epitopes. In line with this interpretation, MAIT cell clones with distinct TCRs responded differentially to a riboflavin metabolite. These results suggest that MAIT cells can discriminate between pathogen-derived ligands in a clonotype-dependent manner, providing a basis for adaptive memory via recruitment of specific repertoires shaped by microbial exposure.

  8. Cbl enforces Vav1 dependence and a restricted pathway of T cell development.

    Directory of Open Access Journals (Sweden)

    Jeffrey Chiang

    Full Text Available Extensive studies of pre-TCR- and TCR-dependent signaling have led to characterization of a pathway deemed essential for efficient T cell development, and comprised of a cascade of sequential events involving phosphorylation of Lck and ZAP-70, followed by phosphorylation of LAT and SLP-76, and subsequent additional downstream events. Of interest, however, reports from our lab as well as others have indicated that the requirements for ZAP-70, LAT, and SLP-76 are partially reversed by inactivation of c-Cbl (Cbl, an E3 ubiquitin ligase that targets multiple molecules for ubiquitination and degradation. Analysis of signaling events in these Cbl knockout models, including the recently reported analysis of SLP-76 transgenes defective in interaction with Vav1, suggested that activation of Vav1 might be a critical event in alternative pathways of T cell development. To extend the analysis of signaling requirements for thymic development, we have therefore assessed the effect of Cbl inactivation on the T cell developmental defects that occur in Vav1-deficient mice. The defects in Vav1-deficient thymic development, including a marked defect in DN3-DN4 transition, were completely reversed by Cbl inactivation, accompanied by enhanced phosphorylation of PLC-γ1 and ERKs in response to pre-TCR/TCR cross-linking of Vav1⁻/⁻Cbl⁻/⁻ DP thymocytes. Taken together, these results suggest a substantially modified paradigm for pre-TCR/TCR signaling and T cell development. The observed consensus pathways of T cell development, including requirements for ZAP-70, LAT, SLP-76, and Vav1, appear to reflect the restriction by Cbl of an otherwise much broader set of molecular pathways capable of mediating T cell development.

  9. A dual inhibitory mechanism sufficient to maintain cell cycle restricted CENP-A assembly

    Science.gov (United States)

    Stankovic, Ana; Guo, Lucie Y.; Mata, João F.; Bodor, Dani L.; Cao, Xing-Jun; Bailey, Aaron O.; Shabanowitz, Jeffrey; Hunt, Donald F.; Garcia, Benjamin A.; Black, Ben E.; Jansen, Lars E.T

    2017-01-01

    Summary Chromatin featuring the H3 variant CENP-A at the centromere is critical for its mitotic function and epigenetic maintenance. Assembly of centromeric chromatin is restricted to G1 phase through inhibitory action of Cdk1/2 kinases in other phases of the cell cycle. Here, we identify the two key targets sufficient to maintain cell cycle control of CENP-A assembly. We uncovered a single phosphorylation site in the licensing factor M18BP1 and a cyclin A binding site in the CENP-A chaperone, HJURP, mediating specific inhibitory phosphorylation. Simultaneous expression of mutant proteins lacking these residues, results in complete uncoupling from the cell cycle. Consequently, CENP-A assembly is fully recapitulated under high Cdk activities, indistinguishable from G1 assembly. We find that Cdk-mediated inhibition is exerted by sequestering active factors away from the centromere. Finally, we show that displacement of M18BP1 from the centromere is critical for the assembly mechanism of CENP-A. PMID:28017591

  10. 腺病毒介导的KDR-HSV-tk系统对血管内皮细胞的杀伤作用及旁观者效应%The killing and bystander effect of KDR-HSV-tk system mediated by adenovirus on vascular endothelial cells

    Institute of Scientific and Technical Information of China (English)

    朱欠元; 曾友根; 张愈延; 李宝金

    2015-01-01

    目的:研究腺病毒介导的KDR-HSV-tk系统对血管内皮细胞的杀伤作用及旁杀效应。方法体外构建受 KDR启动子和巨细胞病毒( CMV)启动子调控并可表达HSV-tk基因的AdKDR-HSV-tk和AdCMV-HSV-tk,经293细胞包装、扩增后,分别感染表达KDR的人脐静脉血管内皮细胞(HUVEC)和不表达KDR的人鼻咽癌细胞CNE-2,建立HUVEC/tk及CNE-2/tk,观察丙氧鸟苷(GCV)处理后 HUVEC 杀伤率及旁观者效应。结果受感染的HUVEC和CNE-2细胞中均有绿色荧光蛋白的表达。在感染复数( MOI)为100的条件下,GCV浓度由0增至50 mg/L 时含 AdKDR-HSV-tk的HUVEC和CNE-2细胞存活率从100%分别降至(23.1±3.9)%和(69.8±3.1)%(P<0.01);感染AdCMV-HSV-tk的HUVEC和 CNE-2细胞存活率从100%分别降至(13.9±2.9)%和(15.7±5.2)%(P<0.05);HUVEC/tk细胞对GCV的敏感性明显高于亲代HUVEC细胞, HUVEC+HUVEC/tk混合细胞的生存率随HUVEC/tk比例的增加而下降,说明AdKDR-HSV-tk/GCV系统不但能杀伤转染tk基因的HUVEC,也能杀伤未导入转染tk基因的HUVEC细胞,存在明显的旁观者效应。结论腺病毒介导的KDR-HSV-tk/GCV系统对血管内皮细胞具有特异的杀伤作用及旁观者效应,为抗肿瘤血管靶向治疗奠定了基础。%Objective To study the killing and bystander effect of KDR-HSV-tk system study of adenovirus mediated vascular endo-thelial cells.Methods AdKDR-HSV-tk and AdCMV-HSV-tk controlled by KDR promoter and cytomegalovirus (CMV) promoter were con-structed in vitro,and infected human umbilical vein endothelial cells (HUVEC) expressing KDR and human nasopharyngeal carcinoma cell line CNE-2 without KDR to establish HUVEC/tk and CNE-2/tk respectively .The killing rate and bystander effect were observed after ganci-clovir(GCV) treatment.Results The infected HUVEC and CNE-2 cells were

  11. Interdisciplinary Evaluation of Broadly-Reactive HLA Class II Restricted Epitopes Eliciting HIV-Specific CD4+T Cell Responses

    DEFF Research Database (Denmark)

    Buggert, M.; Norström, M.; Lundegaard, Claus

    2011-01-01

    , the functional and immunodominant discrepancies of CD4+ T cell responses targeting promiscuous MHC II restricted HIV epitopes remains poorly defined. Thus, utilization of interdisciplinary approaches might aid revealing broadly- reactive peptides eliciting CD4 + T cell responses. Methods: We utilized the novel...... bioinformatic prediction program NetMHCIIpan to select 64 optimized MHC II restricted epitopes located in the HIV Gag, Pol, Env, Nef and Tat regions. The epitopes were selected to cover the global diversity of the virus (multiple subtypes) and the human immune system(diverse MHC II types). Optimized...

  12. Tombusvirus-yeast interactions identify conserved cell-intrinsic viral restriction factors

    Directory of Open Access Journals (Sweden)

    Zsuzsanna eSasvari

    2014-08-01

    Full Text Available To combat viral infections, plants possess innate and adaptive immune pathways, such as RNA silencing, R gene and recessive gene-mediated resistance mechanisms. However, it is likely that additional cell-intrinsic restriction factors (CIRF are also involved in limiting plant virus replication. This review discusses novel CIRFs with antiviral functions, many of them RNA-binding proteins or affecting the RNA binding activities of viral replication proteins. The CIRFs against tombusviruses have been identified in yeast (Saccharomyces cerevisiae, which is developed as an advanced model organism. Grouping of the identified CIRFs based on their known cellular functions and subcellular localization in yeast reveals that TBSV replication is limited by a wide variety of host gene functions. Yeast proteins with the highest connectivity in the network map include the well-characterized Xrn1p 5’-3’ exoribonuclease, Act1p actin protein and Cse4p centromere protein. The protein network map also reveals an important interplay between the pro-viral Hsp70 cellular chaperone and the antiviral co-chaperones, and possibly key roles for the ribosomal or ribosome-associated factors. We discuss the antiviral functions of selected CIRFs, such as the RNA binding nucleolin, ribonucleases, WW-domain proteins, single- and multi-domain cyclophilins, TPR-domain co-chaperones and cellular ion pumps. These restriction factors frequently target the RNA-binding region in the viral replication proteins, thus interfering with the recruitment of the viral RNA for replication and the assembly of the membrane-bound viral replicase. Although many of the characterized CIRFs act directly against TBSV, we propose that the TPR-domain co-chaperones function as guardians of the cellular Hsp70 chaperone system, which is subverted efficiently by TBSV for viral replicase assembly in the absence of the TPR-domain co-chaperones.

  13. Cultured corneas show dendritic spread and restrict herpes simplex virus infection that is not observed with cultured corneal cells

    Science.gov (United States)

    Thakkar, Neel; Jaishankar, Dinesh; Agelidis, Alex; Yadavalli, Tejabhiram; Mangano, Kyle; Patel, Shrey; Tekin, Sati Zeynep; Shukla, Deepak

    2017-01-01

    Herpes simplex virus-1 (HSV-1) causes life-long morbidities in humans. While fever blisters are more common, occasionally the cornea is infected resulting in vision loss. A very intriguing aspect of HSV-1 corneal infection is that the virus spread is normally restricted to only a small fraction of cells on the corneal surface that connect with each other in a dendritic fashion. Here, to develop a comprehensive understanding of the susceptibility of human corneal epithelial (HCE) cells to HSV-1 infection, we infected HCE cells at three different dosages of HSV-1 and measured the outcomes in terms of viral entry, gene and protein expression, viral replication and cytokine induction. In cultured cells, infectivity and cytokine induction were observed even at the minimum viral dosage tested, while a more pronounced dose-restricted infectivity was seen in ex vivo cultures of porcine corneas. Use of fluorescent HSV-1 virions demonstrated a pattern of viral spread ex vivo that mimics clinical findings. We conclude that HCE cell cultures are highly susceptible to infection whereas the cultured corneas demonstrate a higher ability to restrict the infection even in the absence of systemic immune system. The restriction is helped in part by local interferon response and the unique cellular architecture of the cornea. PMID:28198435

  14. Self-protective function of post-conflict bystander affiliation in mandrills.

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    Gabriele Schino

    Full Text Available BACKGROUND: Affiliative interactions exchanged between victims of aggression and individuals not involved in the original aggression (bystanders have been observed in various species. Three hypothetical functions have been proposed for these interactions: consolation, self-protection and substitute reconciliation, but data to test them are scanty. METHODOLOGY/PRINCIPAL FINDINGS: We conducted post-conflict and matched control observations on a captive group of mandrills (Mandrillus sphinx. We found that victims often redirected aggression to bystanders, that they received most affiliation from those bystanders that were frequently the target of redirection, and that bystander affiliation reduced the likelihood of redirection. Bystander affiliation did not reduce the victim's distress (as measured by its scratching rates and was not received primarily from kin/friends. Finally, bystander affiliation did not reduce the likelihood of renewed aggression from the original aggressor. CONCLUSIONS/SIGNIFICANCE: These results provide support for the self-protection hypothesis but not for the consolation and substitute reconciliation hypotheses.

  15. Bystander intervention and fear of crime: evidence from two Chinese communities.

    Science.gov (United States)

    Zhong, Lena Y

    2010-04-01

    From the perspective of prosocial behavior, bystander intervention is conditioned by situational factors; from an informal social control perspective, bystander intervention has been demonstrated to be associated with level of crime and violence at the community level. By drawing on findings in two contrasting communities within a Chinese city, this study investigates the effects of fear of crime and type of community on bystander intervention. It shows that fear of crime and type of community have robust and consistent effects on bystander intervention, controlling for demographic characteristics including sex, age, and education. The implications of the findings are discussed in terms of bystander intervention as both prosocial behavior and informal social control. The findings also question the usefulness of simply casting bystander nonintervention as corrupted morality in China.

  16. Characterisation of a bystander effect induced in human tissue explant cultures by low LET radiation

    Energy Technology Data Exchange (ETDEWEB)

    Motersill, C.; O' Malley, K.; Seymour, C.B

    2002-07-01

    The existence of a bystander effect following both alpha and gamma irradiation of many cell lines is not now in dispute. The significance of this effect for cancer risk assessment and radiotherapy treatment planning requires demonstration of its relevance in vivo. The problem in demonstrating the existence of the effect in vivo is that other systemic effects may mask or confound the effect being investigated and it is practically impossible to attribute an effect in a particular cell to a signal produced in another irradiated cell. To approach this problem, an assay has been developed where fragments of human tissue can be irradiated ex vivo and the media harvested and added to unirradiated, clonogenic cells which have a well characterised and stable response to the bystander signal. The variation in the production of a signal from patient to patient can thus be assessed. The results of a study using tissue from over 100 patients attending Beaumont and St Vincent's Hospitals in Dublin for investigation of urological disorders including follow-up after treatment for transitional cell carcinoma (TCC) and resection of suspect prostatic lesions, are now available. Blood samples from the prostate group were also obtained. The results show that there is variation in the effect of the signal produced by irradiated tissue from different patients. This holds for bladder, prostate and blood. Gender, smoking status and the existence of a malignancy influence the expression of the signal by normal tissue. Male gender, smoking and a pre-existing malignancy all reduce the amount or effect of the signal produced into medium when the tissue is exposed. The effects of exposure to medium containing the signal are transmitted to distant progeny of the exposed cell population. The results may be important not only for understanding radiation risk mechanisms for protection but also for radiotherapy treatment planning where they may open new avenues for development of drugs for

  17. Efficacious early antiviral activity of HIV Gag- and Pol-specific HLA-B 2705-restricted CD8+ T cells

    DEFF Research Database (Denmark)

    Payne, Rebecca P; Kløverpris, Henrik; Sacha, Jonah B;

    2010-01-01

    control of HIV, we first characterized the CD8(+) T-cell responses of nine highly active antiretroviral therapy (HAART)-naïve B 2705-positive subjects. Unexpectedly, we observed a strong response to an HLA-B 2705-restricted Pol epitope, KRKGGIGGY (KY9), in 8/9 subjects. The magnitude of the KY9 response...

  18. Dietary restriction improves repopulation but impairs lymphoid differentiation capacity of hematopoietic stem cells in early aging.

    Science.gov (United States)

    Tang, Duozhuang; Tao, Si; Chen, Zhiyang; Koliesnik, Ievgen Oleksandrovich; Calmes, Philip Gerald; Hoerr, Verena; Han, Bing; Gebert, Nadja; Zörnig, Martin; Löffler, Bettina; Morita, Yohei; Rudolph, Karl Lenhard

    2016-04-01

    Dietary restriction (DR) improves health, delays tissue aging, and elongates survival in flies and worms. However, studies on laboratory mice and nonhuman primates revealed ambiguous effects of DR on lifespan despite improvements in health parameters. In this study, we analyzed consequences of adult-onset DR (24 h to 1 yr) on hematopoietic stem cell (HSC) function. DR ameliorated HSC aging phenotypes, such as the increase in number of HSCs and the skewing toward myeloid-biased HSCs during aging. Furthermore, DR increased HSC quiescence and improved the maintenance of the repopulation capacity of HSCs during aging. In contrast to these beneficial effects, DR strongly impaired HSC differentiation into lymphoid lineages and particularly inhibited the proliferation of lymphoid progenitors, resulting in decreased production of peripheral B lymphocytes and impaired immune function. The study shows that DR-dependent suppression of growth factors and interleukins mediates these divergent effects caused by DR. Supplementation of insulin-like growth factor 1 partially reverted the DR-induced quiescence of HSCs, whereas IL-6/IL-7 substitutions rescued the impairment of B lymphopoiesis exposed to DR. Together, these findings delineate positive and negative effects of long-term DR on HSC functionality involving distinct stress and growth signaling pathways.

  19. Cancer suicide gene therapy with TK.007: superior killing efficiency and bystander effect.

    Science.gov (United States)

    Preuss, Ellen; Muik, Alexander; Weber, Kristoffer; Otte, Jürgen; von Laer, Dorothee; Fehse, Boris

    2011-11-01

    Suicide gene therapy is a promising concept in oncology. We have recently introduced a novel suicide gene, TK.007, which was shown to excel established herpes simplex virus thymidine kinase (HSVtk) variants when used for donor-lymphocyte modification in adoptive immunotherapy models. Here, the potential of TK.007 in killing cancer cells was studied. Initially, we transduced tumour cell lines derived from different neoplasias (glioblastoma, melanoma, lung cancer, colon cancer) with lentiviral LeGO vectors encoding TK.007 or the splice-corrected (sc)HSVtk together with an eGFP/Neo-marker. Based on direct in vitro comparison, we found that TK.007 facilitates more efficient tumour cell killing at significantly lower ganciclovir doses in all tumour cell lines tested. Also, using different readout systems, we found a significantly stronger bystander effect of TK.007 as compared to scHSVtk. Importantly, in vitro data were confirmed in vivo using a subcutaneous G62 glioblastoma model in NOD/SCID mice. In mice transplanted with scHSVtk-positive tumours, treatment with low (10 mg/kg) or standard (50 mg/kg) ganciclovir doses resulted only in short-term growth inhibition or transient tumour remission, respectively. In striking contrast, in the TK.007 group, all animals achieved continuous complete remission after both standard and low-dose ganciclovir. Finally, a substantial bystander effect for TK.007 was also confirmed with the G62 model in vivo, where significantly prolonged survival for mice bearing tumours containing only 10% or 50% TK.007-expressing cells was observed. In summary, our data indicate strongly improved anti-tumour activity of TK.007 as compared to conventional HSVtk. We therefore suppose that TK.007 is an excellent candidate for cancer suicide gene therapy.

  20. Nicotine overrides DNA damage-induced G1/S restriction in lung cells.

    Directory of Open Access Journals (Sweden)

    Takashi Nishioka

    Full Text Available As an addictive substance, nicotine has been suggested to facilitate pro-survival activities (such as anchorage-independent growth or angiogenesis and the establishment of drug resistance to anticancer therapy. Tobacco smoking consists of a variety of carcinogens [such as benzopyrene (BP and nitrosamine derivatives] that are able to cause DNA double strand breaks. However, the effect of nicotine on DNA damage-induced checkpoint response induced by genotoxins remains unknown. In this study, we investigated the events occurred during G(1 arrest induced by γ-radiation or BP in nicotine-treated murine or human lung epithelial cells. DNA synthesis was rapidly inhibited after exposure to γ-radiation or BP treatment, accompanied with the activation of DNA damage checkpoint. When these cells were co-treated with nicotine, the growth restriction was compromised, manifested by upregulation of cyclin D and A, and attenuation of Chk2 phosphorylation. Knockdown of cyclin D or Chk2 by the siRNAs blocked nicotine-mediated effect on DNA damage checkpoint activation. However, nicotine treatment appeared to play no role in nocodazole-induced mitotic checkpoint activation. Overall, our study presented a novel observation, in which nicotine is able to override DNA damage checkpoint activated by tobacco-related carcinogen BP or γ-irradiation. The results not only indicates the potentially important role of nicotine in facilitating the establishment of genetic instability to promote lung tumorigenesis, but also warrants a dismal prognosis for cancer patients who are smokers, heavily exposed second-hand smokers or nicotine users.

  1. Direct ex vivo detection of HLA-DR3-restricted cytomegalovirus- and Mycobacterium tuberculosis-specific CD4+ T cells.

    Science.gov (United States)

    Bronke, Corine; Palmer, Nanette M; Westerlaken, Geertje H A; Toebes, Mireille; van Schijndel, Gijs M W; Purwaha, Veenu; van Meijgaarden, Krista E; Schumacher, Ton N M; van Baarle, Debbie; Tesselaar, Kiki; Geluk, Annemieke

    2005-09-01

    In order to detect epitope-specific CD4+ T cells in mycobacterial or viral infections in the context of human class II major histocompatibility complex protein human leukocyte antigen (HLA)-DR3, two HLA-DR3 tetrameric molecules were successfully produced. One contained an immunodominant HLA-DR3-restricted T-cell epitope derived from the 65-kDa heat-shock protein of Mycobacterium tuberculosis, peptide 1-13. For the other tetramer, we used an HLA-DR3-restricted T-cell epitope derived from cytomegalovirus (CMV) pp65 lower matrix protein, peptide 510-522, which induced high levels of interferon (IFN)-gamma-producing CD4+ T cells in three of four HLA-DR3-positive CMV-seropositive individuals up to 0.84% of CD4+ T cells by intracellular cytokine staining. In peripheral blood mononuclear cells from M. tuberculosis-exposed, Mycobacterium bovis bacille Calmette-Guérin (BCG)-vaccinated, or CMV-seropositive individuals, we were able to directly detect with both tetramers epitope-specific T cells up to 0.62% and 0.45% of the CD4+ T-cell population reactive to M. tuberculosis and CMV, respectively. After a 6-day culture with peptide p510-522, the frequency of CMV-specific tetramer-binding T cells was expanded up to 9.90% tetramer+ CFSElow (5,6-carboxyfluorescein diacetate succinimidyl ester) cells within the CD4+ T-cell population, further confirming the specificity of the tetrameric molecules. Thus, HLA-DR3/peptide tetrameric molecules can be used to investigate HLA-DR3-restricted antigen-specific CD4+ T cells in clinical disease or after vaccination.

  2. A model for cell wall dissolution in mating yeast cells: polarized secretion and restricted diffusion of cell wall remodeling enzymes induces local dissolution.

    Directory of Open Access Journals (Sweden)

    Lori B Huberman

    Full Text Available Mating of the budding yeast, Saccharomyces cerevisiae, occurs when two haploid cells of opposite mating types signal using reciprocal pheromones and receptors, grow towards each other, and fuse to form a single diploid cell. To fuse, both cells dissolve their cell walls at the point of contact. This event must be carefully controlled because the osmotic pressure differential between the cytoplasm and extracellular environment causes cells with unprotected plasma membranes to lyse. If the cell wall-degrading enzymes diffuse through the cell wall, their concentration would rise when two cells touched each other, such as when two pheromone-stimulated cells adhere to each other via mating agglutinins. At the surfaces that touch, the enzymes must diffuse laterally through the wall before they can escape into the medium, increasing the time the enzymes spend in the cell wall, and thus raising their concentration at the point of attachment and restricting cell wall dissolution to points where cells touch each other. We tested this hypothesis by studying pheromone treated cells confined between two solid, impermeable surfaces. This confinement increases the frequency of pheromone-induced cell death, and this effect is diminished by reducing the osmotic pressure difference across the cell wall or by deleting putative cell wall glucanases and other genes necessary for efficient cell wall fusion. Our results support the model that pheromone-induced cell death is the result of a contact-driven increase in the local concentration of cell wall remodeling enzymes and suggest that this process plays an important role in regulating cell wall dissolution and fusion in mating cells.

  3. A model for cell wall dissolution in mating yeast cells: polarized secretion and restricted diffusion of cell wall remodeling enzymes induces local dissolution.

    Science.gov (United States)

    Huberman, Lori B; Murray, Andrew W

    2014-01-01

    Mating of the budding yeast, Saccharomyces cerevisiae, occurs when two haploid cells of opposite mating types signal using reciprocal pheromones and receptors, grow towards each other, and fuse to form a single diploid cell. To fuse, both cells dissolve their cell walls at the point of contact. This event must be carefully controlled because the osmotic pressure differential between the cytoplasm and extracellular environment causes cells with unprotected plasma membranes to lyse. If the cell wall-degrading enzymes diffuse through the cell wall, their concentration would rise when two cells touched each other, such as when two pheromone-stimulated cells adhere to each other via mating agglutinins. At the surfaces that touch, the enzymes must diffuse laterally through the wall before they can escape into the medium, increasing the time the enzymes spend in the cell wall, and thus raising their concentration at the point of attachment and restricting cell wall dissolution to points where cells touch each other. We tested this hypothesis by studying pheromone treated cells confined between two solid, impermeable surfaces. This confinement increases the frequency of pheromone-induced cell death, and this effect is diminished by reducing the osmotic pressure difference across the cell wall or by deleting putative cell wall glucanases and other genes necessary for efficient cell wall fusion. Our results support the model that pheromone-induced cell death is the result of a contact-driven increase in the local concentration of cell wall remodeling enzymes and suggest that this process plays an important role in regulating cell wall dissolution and fusion in mating cells.

  4. A GM-CSF and CD40L bystander vaccine is effective in a murine breast cancer model

    Directory of Open Access Journals (Sweden)

    Soliman H

    2015-12-01

    Full Text Available Hatem Soliman,1 Melanie Mediavilla-Varela,2 Scott J Antonia,3 1Department of Women's Oncology and Experimental Therapeutics, 2Department of Immunology, 3Department of Thoracic Oncology, Moffitt Cancer Center, Tampa, FL, USA Background: There is increasing interest in using cancer vaccines to treat breast cancer patients in the adjuvant setting to prevent recurrence in high risk situations or in combination with other immunomodulators in the advanced setting. Current peptide vaccines are limited by immunologic compatibility issues, and engineered autologous cellular vaccines are difficult to produce on a large scale. Using standardized bystander cell lines modified to secrete immune stimulating adjuvant substances can greatly enhance the ability to produce immunogenic cellular vaccines using unmodified autologous cells or allogeneic medical grade tumor cell lines as targets. We investigated the efficacy of a cellular vaccine using B78H1 bystander cell lines engineered to secrete granulocyte macrophage-colony stimulating factor and CD40 ligand (BCG in a murine model of breast cancer. Methods: Five-week-old female BALB/c mice were injected orthotopically in the mammary fat pad with 4T1 tumor cells. Treatment consisted of irradiated 4T1 ± BCG cells given subcutaneously every 4 days and was repeated three times per mouse when tumors became palpable. Tumors were measured two to three times per week for 25 days. The vaccine's activity was confirmed in a second experiment using Lewis lung carcinoma (LLC cells in C57BL/6 mice to exclude a model specific effect. Interferon-γ (IFN-γ and interleukin-2 (IL-2 enzyme-linked immunospots (ELISPOTS were performed on splenic lymphocytes incubated with 4T1 lysates along with immunohistochemistry for CD3 on tumor sections. Results: Tumor growth was significantly inhibited in the 4T1-BCG and LLC-BCG treatment groups when compared to 4T1 and LLC treatment groups. There were higher levels of IL-2 and IFN

  5. Alpha-particle-induced bystander effects between zebrafish embryos in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Yum, E.H.W.; Choi, V.W.Y.; Nikezic, D. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Li, V.W.T.; Cheng, S.H. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2009-10-15

    Dechorionaed embryos of the zebrafish, Danio rerio, at 1.5 h post-fertilization (hpf) were irradiated with alpha particles from an {sup 241}Am source. Thin polyallyldiglycol carbonate (PADC) films with a thickness of 16 mum were used as support substrates for holding the embryos and recorded alpha-particle hit positions, and thus enabled calculation of the dose absorbed by the embryos. The irradiated embryos were subsequently incubated with naive (unirradiated) embryos in such a way that the irradiated and naive embryos were spatially separated but the medium was shared. Acridine orange was used to perform in vital staining to show cell deaths in the naive embryos at 24 hpf. Our results gave evidence in supporting the existence of alpha-particle-induced bystander effects between zebrafish embryos in vivo, and a general positive correlation between the cell death signals in the naive embryos and the alpha-particle dose absorbed by the irradiated embryos.

  6. The dendritic cell subtype-restricted C-type lectin Clec9A is a target for vaccine enhancement

    OpenAIRE

    Caminschi, Irina; Proietto, Anna I.; Ahmet, Fatma; Kitsoulis, Susie; Shin Teh, Joo; Lo, Jennifer C. Y.; Rizzitelli, Alexandra; Wu, Li; Vremec, David; van Dommelen, Serani L.H.; Campbell, Ian K.; Maraskovsky, Eugene; Braley, Hal; Davey, Gayle M.; Mottram, Patricia

    2008-01-01

    A novel dendritic cell (DC)–restricted molecule, Clec9A, was identified by gene expression profiling of mouse DC subtypes. Based on sequence similarity, a human ortholog was identified. Clec9A encodes a type II membrane protein with a single extracellular C-type lectin domain. Both the mouse Clec9A and human CLEC9A were cloned and expressed, and monoclonal antibodies (mAbs) against each were generated. Surface staining revealed that Clec9A was selective for mouse DCs and was restricted to the...

  7. Hiding Lipid Presentation: Viral Interference with CD1d-Restricted Invariant Natural Killer T (iNKT Cell Activation

    Directory of Open Access Journals (Sweden)

    Maaike E. Ressing

    2012-10-01

    Full Text Available The immune system plays a major role in protecting the host against viral infection. Rapid initial protection is conveyed by innate immune cells, while adaptive immunity (including T lymphocytes requires several days to develop, yet provides high specificity and long-lasting memory. Invariant natural killer T (iNKT cells are an unusual subset of T lymphocytes, expressing a semi-invariant T cell receptor together with markers of the innate NK cell lineage. Activated iNKT cells can exert direct cytolysis and can rapidly release a variety of immune-polarizing cytokines, thereby regulating the ensuing adaptive immune response. iNKT cells recognize lipids in the context of the antigen-presenting molecule CD1d. Intriguingly, CD1d-restricted iNKT cells appear to play a critical role in anti-viral defense: increased susceptibility to disseminated viral infections is observed both in patients with iNKT cell deficiency as well as in CD1d- and iNKT cell-deficient mice. Moreover, viruses have recently been found to use sophisticated strategies to withstand iNKT cell-mediated elimination. This review focuses on CD1d-restricted lipid presentation and the strategies viruses deploy to subvert this pathway.

  8. Antenatal taurine reduces cerebral cell apoptosis in fetal rats with intrauterine growth restriction*

    Institute of Scientific and Technical Information of China (English)

    Jing Liu; Xiaofeng Wang; Ying Liu; Na Yang; Jing Xu; Xiaotun Ren

    2013-01-01

    From pregnancy to parturition, Sprague-Dawley rats were daily administered a low protein diet to establish a model of intrauterine growth restriction. From the 12th day of pregnancy, 300 mg/kg rine was daily added to food until spontaneous delivery occurred. Brain tissues from normal neo-natal rats at 6 hours after delivery, neonatal rats with intrauterine growth restriction, and neonatal rats with intrauterine growth restriction undergoing taurine supplement were obtained for further experiments. The terminal deoxyribonucleotidyl transferase (TdT)-mediated biotin-16-dUTP nick-end labeling assay revealed that the number of apoptotic cel s in the brain tissue of neonatal rats with intrauterine growth restriction significantly increased. Taurine supplement in pregnant rats reduced cel apoptosis in brain tissue from neonatal rats with intrauterine growth restriction. nohistochemical staining revealed that taurine supplement increased glial cel line-derived neuro-trophic factor expression and decreased caspase-3 expression in the cerebral cortex of intrauterine growth-restricted fetal rats. These results indicate that taurine supplement reduces cel apoptosis through the glial cel line-derived neurotrophic factor-caspase-3 signaling pathway, resulting in a protective effect on the intrauterine growth-restricted fetal rat brain.

  9. Requirement of cAMP signaling for Schwann cell differentiation restricts the onset of myelination.

    Science.gov (United States)

    Bacallao, Ketty; Monje, Paula V

    2015-01-01

    Isolated Schwann cells (SCs) respond to cAMP elevation by adopting a differentiated post-mitotic state that exhibits high levels of Krox-20, a transcriptional enhancer of myelination, and mature SC markers such as the myelin lipid galactocerebroside (O1). To address how cAMP controls myelination, we performed a series of cell culture experiments which compared the differentiating responses of isolated and axon-related SCs to cAMP analogs and ascorbate, a known inducer of axon ensheathment, basal lamina formation and myelination. In axon-related SCs, cAMP induced the expression of Krox-20 and O1 without a concomitant increase in the expression of myelin basic protein (MBP) and without promoting axon ensheathment, collagen synthesis or basal lamina assembly. When cAMP was provided together with ascorbate, a dramatic enhancement of MBP expression occurred, indicating that cAMP primes SCs to form myelin only under conditions supportive of basal lamina formation. Experiments using a combination of cell permeable cAMP analogs and type-selective adenylyl cyclase (AC) agonists and antagonists revealed that selective transmembrane AC (tmAC) activation with forskolin was not sufficient for full SC differentiation and that the attainment of an O1 positive state also relied on the activity of the soluble AC (sAC), a bicarbonate sensor that is insensitive to forskolin and GPCR activation. Pharmacological and immunological evidence indicated that SCs expressed sAC and that sAC activity was required for morphological differentiation and the expression of myelin markers such as O1 and protein zero. To conclude, our data indicates that cAMP did not directly drive myelination but rather the transition into an O1 positive state, which is perhaps the most critical cAMP-dependent rate limiting step for the onset of myelination. The temporally restricted role of cAMP in inducing differentiation independently of basal lamina formation provides a clear example of the uncoupling of signals

  10. Requirement of cAMP signaling for Schwann cell differentiation restricts the onset of myelination.

    Directory of Open Access Journals (Sweden)

    Ketty Bacallao

    Full Text Available Isolated Schwann cells (SCs respond to cAMP elevation by adopting a differentiated post-mitotic state that exhibits high levels of Krox-20, a transcriptional enhancer of myelination, and mature SC markers such as the myelin lipid galactocerebroside (O1. To address how cAMP controls myelination, we performed a series of cell culture experiments which compared the differentiating responses of isolated and axon-related SCs to cAMP analogs and ascorbate, a known inducer of axon ensheathment, basal lamina formation and myelination. In axon-related SCs, cAMP induced the expression of Krox-20 and O1 without a concomitant increase in the expression of myelin basic protein (MBP and without promoting axon ensheathment, collagen synthesis or basal lamina assembly. When cAMP was provided together with ascorbate, a dramatic enhancement of MBP expression occurred, indicating that cAMP primes SCs to form myelin only under conditions supportive of basal lamina formation. Experiments using a combination of cell permeable cAMP analogs and type-selective adenylyl cyclase (AC agonists and antagonists revealed that selective transmembrane AC (tmAC activation with forskolin was not sufficient for full SC differentiation and that the attainment of an O1 positive state also relied on the activity of the soluble AC (sAC, a bicarbonate sensor that is insensitive to forskolin and GPCR activation. Pharmacological and immunological evidence indicated that SCs expressed sAC and that sAC activity was required for morphological differentiation and the expression of myelin markers such as O1 and protein zero. To conclude, our data indicates that cAMP did not directly drive myelination but rather the transition into an O1 positive state, which is perhaps the most critical cAMP-dependent rate limiting step for the onset of myelination. The temporally restricted role of cAMP in inducing differentiation independently of basal lamina formation provides a clear example of the

  11. MicroRNA inhibition fine-tunes and provides robustness to the restriction point switch of the cell cycle

    Science.gov (United States)

    del Rosario, Ricardo C. H.; Damasco, Joseph Ray Clarence G.; Aguda, Baltazar D.

    2016-01-01

    The restriction point marks a switch in G1 from growth factor-dependent to growth factor-independent progression of the cell cycle. The proper regulation of this switch is important for normal cell processes; aberrations could result in a number of diseases such as cancer, neurodegenerative disorders, stroke and myocardial infarction. To further understand the regulation of the restriction point, we extended a mathematical model of the Rb-E2F pathway to include members of the microRNA cluster miR-17-92. Our mathematical analysis shows that microRNAs play an essential role in fine-tuning and providing robustness to the switch. We also demonstrate how microRNA regulation can steer cells in or out of cancer states. PMID:27610602

  12. Transcriptional Reprogramming of Mature CD4+ T helper Cells generates distinct MHC class II-restricted Cytotoxic T Lymphocytes

    Science.gov (United States)

    Mucida, Daniel; Husain, Mohammad Mushtaq; Muroi, Sawako; van Wijk, Femke; Shinnakasu, Ryo; Naoe, Yoshinori; Reis, Bernardo Sgarbi; Huang, Yujun; Lambolez, Florence; Docherty, Michael; Attinger, Antoine; Shui, Jr-Wen; Kim, Gisen; Lena, Christopher J.; Sakaguchi, Shinya; Miyamoto, Chizuko; Wang, Peng; Atarashi, Koji; Park, Yunji; Nakayama, Toshinori; Honda, Kenya; Ellmeier, Wilfried; Kronenberg, Mitchell; Taniuchi, Ichiro; Cheroutre, Hilde

    2013-01-01

    TCRαβ thymocytes differentiate to either CD8αβ cytotoxic T lymphocytes or CD4+ T helper cells. This functional dichotomy is controlled by key transcription factors, including the T helper master regulator, ThPOK, which suppresses the cytolytic program in MHC class II-restricted CD4+ thymocytes. ThPOK continues to repress CD8-lineage genes in mature CD4+ T cells, even as they differentiate to T helper effector subsets. Here we show that the T helper-fate was not fixed and that mature antigen-stimulated CD4+ T cells could terminate Thpok expression and reactivate CD8-lineage genes. This unexpected plasticity resulted in the post-thymic termination of the T helper-program and the functional differentiation of distinct MHC class II-restricted CD4+ cytotoxic T lymphocytes. PMID:23334788

  13. Do Sexual Assault Bystander Interventions Change Men's Intentions? Applying the Theory of Normative Social Behavior to Predicting Bystander Outcomes.

    Science.gov (United States)

    Mabry, Amanda; Turner, Monique Mitchell

    2016-01-01

    The high prevalence of sexual assault on college campuses has led to the implementation of health communication programs to prevent sexual assault. A few novel programs focus on primary prevention by targeting social norms related to gender and masculinity among men through bystander intervention. Guided by the theory of normative social behavior, this study sought to examine the relative effect of campaigns communicating positive versus negative injunctive norms and the interaction between exposure to such campaign messages and perceived descriptive norms and relevant cognitive moderators (e.g., outcome expectations, injunctive norms, group identity, ego involvement) among men. A 2 (high/low descriptive norms) × 2 (high/low moderator) × 3 (public service announcement) independent groups quasi-experimental design (N = 332) was used. Results indicated that messages communicating positive injunctive norms were most effective among men who were least likely to engage in bystander intervention. Furthermore, descriptive norms played a significant role in behavioral intentions, such that those with stronger norms were more likely to report intentions to engage in bystander behaviors in the future. Similarly, the moderators of aspiration, injunctive norms, social approval, and ego involvement had a significant positive effect on behavioral intentions. These findings have important implications for future message design strategy and audience segmentation.

  14. Junín virus infection of human hematopoietic progenitors impairs in vitro proplatelet formation and platelet release via a bystander effect involving type I IFN signaling.

    Science.gov (United States)

    Pozner, Roberto G; Ure, Agustín E; Jaquenod de Giusti, Carolina; D'Atri, Lina P; Italiano, Joseph E; Torres, Oscar; Romanowski, Victor; Schattner, Mirta; Gómez, Ricardo M

    2010-04-15

    Argentine hemorrhagic fever (AHF) is an endemo-epidemic disease caused by Junín virus (JUNV), a member of the arenaviridae family. Although a recently introduced live attenuated vaccine has proven to be effective, AHF remains a potentially lethal infection. Like in other viral hemorrhagic fevers (VHF), AHF patients present with fever and hemorrhagic complications. Although the causes of the bleeding are poorly understood, impaired hemostasis, endothelial cell dysfunction and low platelet counts have been described. Thrombocytopenia is a common feature in VHF syndromes, and it is a major sign for its diagnosis. However, the underlying pathogenic mechanism has not yet been elucidated. We hypothesized that thrombocytopenia results from a viral-triggered alteration of the megakaryo/thrombopoiesis process. Therefore, we evaluated the impact of JUNV on megakaryopoiesis using an in vitro model of human CD34+ cells stimulated with thrombopoietin. Our results showed that CD34+ cells are infected with JUNV in a restricted fashion. Infection was transferrin receptor 1 (TfR1)-dependent and the surface expression of TfR1 was higher in infected cultures, suggesting a novel arenaviral dissemination strategy in hematopoietic progenitor cells. Although proliferation, survival, and commitment in JUNV-infected cultures were normal, viral infection impaired thrombopoiesis by decreasing in vitro proplatelet formation, platelet release, and P-selectin externalization via a bystander effect. The decrease in platelet release was also TfR1-dependent, mimicked by poly(I:C), and type I interferon (IFN alpha/beta) was implicated as a key paracrine mediator. Among the relevant molecules studied, only the transcription factor NF-E2 showed a moderate decrease in expression in megakaryocytes from either infected cultures or after type I IFN treatment. Moreover, type I IFN-treated megakaryocytes presented ultrastructural abnormalities resembling the reported thrombocytopenic NF-E2(-/-) mouse

  15. A hybrid approach for predicting promiscuous MHC class I restricted T cell epitopes

    Indian Academy of Sciences (India)

    Manoj Bhasin; G P S Raghava

    2007-01-01

    In the present study, a systematic attempt has been made to develop an accurate method for predicting MHC class I restricted T cell epitopes for a large number of MHC class I alleles. Initially, a quantitative matrix (QM)-based method was developed for 47 MHC class I alleles having at least 15 binders. A secondary artificial neural network (ANN)-based method was developed for 30 out of 47 MHC alleles having a minimum of 40 binders. Combination of these ANN- and QM-based prediction methods for 30 alleles improved the accuracy of prediction by 6% compared to each individual method. Average accuracy of hybrid method for 30 MHC alleles is 92.8%. This method also allows prediction of binders for 20 additional alleles using QM that has been reported in the literature, thus allowing prediction for 67 MHC class I alleles. The performance of the method was evaluated using jack-knife validation test. The performance of the methods was also evaluated on blind or independent data. Comparison of our method with existing MHC binder prediction methods for alleles studied by both methods shows that our method is superior to other existing methods. This method also identifies proteasomal cleavage sites in antigen sequences by implementing the matrices described earlier. Thus, the method that we discover allows the identification of MHC class I binders (peptides binding with many MHC alleles) having proteasomal cleavage site at C-terminus. The user-friendly result display format (HTML-II) can assist in locating the promiscuous MHC binding regions from antigen sequence. The method is available on the web at www.imtech.res.in/raghava/nhlapred and its mirror site is available at http://bioinformatics.uams.edu/mirror/nhlapred/.

  16. Factors that restrict intestinal cell permeation of cyclic prodrugs of an opioid peptide (DADLE)

    DEFF Research Database (Denmark)

    Ouyang, Hui; Chen, Weiqing; Andersen, Thomas E;

    2009-01-01

    The objective of this study was to determine the relative importance of metabolism by cytochrome P450 (CYP) enzymes versus efflux by P-glycoprotein (P-gp) in restricting the intestinal mucosal permeation of cyclic prodrugs (AOA-DADLE, CA-DADLE, OMCA-DADLE) of the opioid peptide DADLE (H......-gp), not metabolic enzymes (e.g., CYP 3A, esterases), restrict the permeation of peptide prodrugs across the rat intestinal mucosa....

  17. Identification of MHC class II restricted T-cell-mediated reactivity against MHC class I binding Mycobacterium tuberculosis peptides.

    Science.gov (United States)

    Wang, Mingjun; Tang, Sheila T; Stryhn, Anette; Justesen, Sune; Larsen, Mette V; Dziegiel, Morten H; Lewinsohn, David M; Buus, Søren; Lund, Ole; Claesson, Mogens H

    2011-04-01

    Major histocompatibility complex (MHC) class I restricted cytotoxic T lymphocytes (CTL) are known to play an important role in the control of Mycobacterium tuberculosis infection so identification of CTL epitopes from M. tuberculosis is of importance for the development of effective peptide-based vaccines. In the present work, bioinformatics technology was employed to predict binding motifs of 9mer peptides derived from M. tuberculosis for the 12 HLA-I supertypes. Subsequently, the predicted peptides were synthesized and assayed for binding to HLA-I molecules in a biochemically based system. The antigenicity of a total of 157 peptides with measured affinity for HLA-I molecules of K(D) ≤ 500 nM were evaluated using peripheral blood T cells from strongly purified protein derivative reactive healthy donors. Of the 157 peptides, eight peptides (5%) were found to induce T-cell responses. As judged from blocking with HLA class I and II subtype antibodies in the ELISPOT assay culture, none of the eight antigenic peptides induced HLA class I restricted CD8(+) T-cell responses. Instead all responses were blocked by pan-HLA class II and anti-HLA-DR antibodies. In addition, CD4(+) T-cell depletion before the 10 days of expansion, resulted in total loss of reactivity in the ELISPOT culture for most peptide specificities. FACS analyses with intracellular interferon-γ staining of T cells expanded in the presence of M. tuberculosis peptides confirmed that the responsive cells were indeed CD4(+). In conclusion, T-cell immunity against HLA-I binding 9mer M. tuberculosis-derived peptides might in many cases turn out to be mediated by CD4(+) T cells and restricted by HLA-II molecules. The use of 9mer peptides recognized by both CD8(+) and CD4(+) T cells might be of importance for the development of future M. tuberculosis peptide-based vaccines.

  18. Bystander activation of CD8+ T lymphocytes during experimental mycobacterial infection.

    Science.gov (United States)

    Gilbertson, Brad; Germano, Susie; Steele, Pauline; Turner, Steven; Fazekas de St Groth, Barbara; Cheers, Christina

    2004-12-01

    Infection of C57BL/6 mice with Mycobacterium avium leads to the activation of both CD4+ and CD8+ gamma interferon (IFN-gamma)-producing T cells, although the CD8+ cells play no role in protection against infection. Using transfer of different lines of transgenic T cells with T-cell receptors (TCRs) which recognize irrelevant antigens, we show here that transferred CD8+ T cells from two of the three lines were activated to the same degree as the host cells, suggesting that the majority of the IFN-gamma-producing CD8+ T cells of the host represented bystander activation. The third line, specific for the male HY antigen, showed no activation. Activation required the participation of the CD28 coreceptor on T cells and was unaffected by the removal of CD44(hi) (memory phenotype) T cells. The transferred CD8+ T cells proliferated in vivo, although this was not essential for IFN-gamma production. Taken together, these data are highly reminiscent of homeostatic proliferation of TCR transgenic T cells upon transfer to lymphopenic hosts, and suggest low-affinity stimulation through the TCR, possibly by self peptides. The findings are discussed in relation to homeostatic proliferation and their significance in the possible induction of autoimmune disease.

  19. Restricted TET2 Expression in Germinal Center Type B Cells Promotes Stringent Epstein-Barr Virus Latency.

    Science.gov (United States)

    Wille, Coral K; Li, Yangguang; Rui, Lixin; Johannsen, Eric C; Kenney, Shannon C

    2017-03-01

    Epstein-Barr virus (EBV) latently infects normal B cells and contributes to the development of certain human lymphomas. Newly infected B cells support a highly transforming form (type III) of viral latency; however, long-term EBV infection in immunocompetent hosts is limited to B cells with a more restricted form of latency (type I) in which most viral gene expression is silenced by promoter DNA methylation. How EBV converts latency type is unclear, although it is known that type I latency is associated with a germinal center (GC) B cell phenotype, and type III latency with an activated B cell (ABC) phenotype. In this study, we have examined whether expression of TET2, a cellular enzyme that initiates DNA demethylation by converting 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC), regulates EBV latency type in B cells. We found that TET2 expression is inhibited in normal GC cells and GC type lymphomas. In contrast, TET2 is expressed in normal naive B cells and ABC type lymphomas. We also demonstrate that GC type cell lines have increased 5mC levels and reduced 5hmC levels in comparison to those of ABC type lines. Finally, we show that TET2 promotes the ability of the EBV transcription factor EBNA2 to convert EBV-infected cells from type I to type III latency. These findings demonstrate that TET2 expression is repressed in GC cells independent of EBV infection and suggest that TET2 promotes type III EBV latency in B cells with an ABC or naive phenotype by enhancing EBNA2 activation of methylated EBV promoters.IMPORTANCE EBV establishes several different types of viral latency in B cells. However, cellular factors that determine whether EBV enters the highly transforming type III latency, versus the more restricted type I latency, have not been well characterized. Here we show that TET2, a cellular enzyme that initiates DNA demethylation by converting 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC), regulates EBV latency type in B cells by

  20. Non-major histocompatibility complex-restricted cytotoxic activity of blood mononuclear cells stimulated with secreted mycobacterial proteins and other mycobacterial antigens

    DEFF Research Database (Denmark)

    Ravn, P; Pedersen, B K

    1994-01-01

    Several observations indicate that non-major histocompatibility complex (MHC)-restricted cytotoxicity, mediated for example by natural killer cells and lymphokine-activated killer cells, may serve as an important antimicrobial defense mechanism. The purpose of the present study was to investigate...... the influences of different mycobacterial antigens on non-MHC-restricted cytotoxicity and further to investigate the ways by which various lymphocyte subpopulations contribute to the development of this cytotoxicity. Non-MHC-restricted cytotoxicity was induced following stimulation of mononuclear cells...... the influence of CD4+ cells on the development of non-MHC-restricted cytotoxicity, blood mononuclear cells were depleted of CD4+ cells before antigen stimulation. When mononuclear cells were incubated with purified protein derivative or short-term culture filtrate in the absence of CD4+ cells, cytotoxic...

  1. Individual Motivations and Characteristics Associated with Bystander Intervention during Bullying Episodes among Children and Youth

    Science.gov (United States)

    Cappadocia, M. Catherine; Pepler, Debra; Cummings, Joanne G.; Craig, Wendy

    2012-01-01

    The aim of the current study was to explore bystander experiences during bullying episodes among children and youth attending a residential summer camp by investigating rates of witnessing and intervention, as well as individual motivations and characteristics associated with bystander intervention. The majority of children had witnessed bullying…

  2. What Would You Do? Strategies for Bystander Intervention to Prevent Sexual Violence by College Students

    Science.gov (United States)

    McMahon, Sarah; Hoffman, Melanie Lowe; McMahon, Sheila M.; Zucker, Sharon; Koenick, Ruth Anne

    2013-01-01

    Bystander education is an increasingly utilized strategy for addressing sexual assault prevention and intervention on U.S. college campuses. Given the paramount importance of peers among college students, what types of pro-social bystander interventions do students themselves deem feasible in the campus context? Drawing on self-reports from…

  3. Conceptualizing the Engaging Bystander Approach to Sexual Violence Prevention on College Campuses

    Science.gov (United States)

    McMahon, Sarah; Postmus, Judy L.; Koenick, Ruth Anne

    2011-01-01

    Bystander intervention offers promise as a sexual violence prevention tool for student affairs administrators on college campuses, but the conceptualization and definition of the approach is in its infancy and needs further development. In an effort to emphasize the potential role of bystanders in the primary prevention of sexual violence, we put…

  4. On Standby? A Comparison of Online and Offline Witnesses to Bullying and Their Bystander Behaviour

    Science.gov (United States)

    Quirk, Roslynn; Campbell, Marilyn

    2015-01-01

    Given their ubiquitous presence as witnesses to school-yard bullying, the role of the "bystander" has been studied extensively. The prevalence and behaviour of bystanders to "cyberbullying," however, is less understood. In an anonymous, school-based questionnaire, 716 secondary school students from South-East Queensland…

  5. Therapeutic Vaccination Using Cationic Liposome-Adjuvanted HIV Type 1 Peptides Representing HLA-Supertype-Restricted Subdominant T Cell Epitopes

    DEFF Research Database (Denmark)

    Román, Victor Raúl Gómez; Jensen, Kristoffer Jarlov; Jensen, Sanne Skov;

    2013-01-01

    We have designed a therapeutic HIV-1 vaccine concept based on peptides together with the adjuvant CAF01. Peptides represented 15 HLA-supertype-restricted subdominant and conserved CD8 T cell epitopes and three CD4 T-helper cell epitopes. In this phase I clinical trial, safety and immunogenicity...... were assessed in untreated HIV-1-infected individuals in Guinea-Bissau, West Africa. Twenty-three HIV-1-infected individuals were randomized to receive placebo (n=5) or vaccine (n=18). Safety was appraised by clinical follow-up combined with monitoring of biochemistry, hematology, CD4 T cell counts......, and HIV-1 viral loads. T cell immunogenicity was monitored longitudinally by interferon (IFN)-γ ELISpot. New vaccine-specific T cell responses were induced in 6/14 vaccinees for whom ELISpot data were valid. CD4 T cell counts and viral loads were stable. The study shows that therapeutic immunization...

  6. Cancer mediates effector T cell dysfunction by targeting microRNAs and EZH2 via glycolysis restriction

    Science.gov (United States)

    Zhao, Ende; Maj, Tomasz; Kryczek, Ilona; Li, Wei; Wu, Ke; Zhao, Lili; Wei, Shuang; Crespo, Joel; Wan, Shanshan; Vatan, Linda; Szeliga, Wojciech; Shao, Irene; Wang, Yin; Liu, Yan; Varambally, Sooryanarayana; Chinnaiyan, Arul M.; Welling, Theodore H.; Marquez, Victor E.; Kotarski, Jan; Wang, Hongbo; Wang, Zehua; Zhang, Yi; Liu, Rebecca; Wang, Guobin; Zou, Weiping

    2015-01-01

    Aerobic glycolysis regulates T cell function. However, if and how primary cancer alters T cell glycolytic metabolism and affects tumor immunity remains a question in cancer patients. Here we report that ovarian cancers imposed glucose restriction on T cells and dampened their function via maintaining high expression of microRNA101 and microRNA26a, which constrained expression of the methyltransferase EZH2. EZH2 activated the Notch pathway by suppressing Notch repressors, Numb and Fbxw7, via H3K27me3, and consequently stimulated T cell polyfunctional cytokine expression and promoted their survival via Bcl-2 signaling. Moreover, human shRNA-knockdown-EZH2-deficient T cells elicited poor anti-tumor immunity. EZH2+CD8+ T cells were associated with improved cancer patient survival. Together, the data unveil a novel metabolic target and mechanism of cancer immune evasion. PMID:26523864

  7. DNA methylation restricts lineage-specific functions of transcription factor Gata4 during embryonic stem cell differentiation.

    Directory of Open Access Journals (Sweden)

    Masaaki Oda

    2013-06-01

    Full Text Available DNA methylation changes dynamically during development and is essential for embryogenesis in mammals. However, how DNA methylation affects developmental gene expression and cell differentiation remains elusive. During embryogenesis, many key transcription factors are used repeatedly, triggering different outcomes depending on the cell type and developmental stage. Here, we report that DNA methylation modulates transcription-factor output in the context of cell differentiation. Using a drug-inducible Gata4 system and a mouse embryonic stem (ES cell model of mesoderm differentiation, we examined the cellular response to Gata4 in ES and mesoderm cells. The activation of Gata4 in ES cells is known to drive their differentiation to endoderm. We show that the differentiation of wild-type ES cells into mesoderm blocks their Gata4-induced endoderm differentiation, while mesoderm cells derived from ES cells that are deficient in the DNA methyltransferases Dnmt3a and Dnmt3b can retain their response to Gata4, allowing lineage conversion from mesoderm cells to endoderm. Transcriptome analysis of the cells' response to Gata4 over time revealed groups of endoderm and mesoderm developmental genes whose expression was induced by Gata4 only when DNA methylation was lost, suggesting that DNA methylation restricts the ability of these genes to respond to Gata4, rather than controlling their transcription per se. Gata4-binding-site profiles and DNA methylation analyses suggested that DNA methylation modulates the Gata4 response through diverse mechanisms. Our data indicate that epigenetic regulation by DNA methylation functions as a heritable safeguard to prevent transcription factors from activating inappropriate downstream genes, thereby contributing to the restriction of the differentiation potential of somatic cells.

  8. Glucose restriction induces cell death in parental but not in homeodomain-interacting protein kinase 2-depleted RKO colon cancer cells: molecular mechanisms and implications for tumor therapy.

    Science.gov (United States)

    Garufi, A; Ricci, A; Trisciuoglio, D; Iorio, E; Carpinelli, G; Pistritto, G; Cirone, M; D'Orazi, G

    2013-05-23

    Tumor cell tolerance to nutrient deprivation can be an important factor for tumor progression, and may depend on deregulation of both oncogenes and oncosuppressor proteins. Homeodomain-interacting protein kinase 2 (HIPK2) is an oncosuppressor that, following its activation by several cellular stress, induces cancer cell death via p53-dependent or -independent pathways. Here, we used genetically matched human RKO colon cancer cells harboring wt-HIPK2 (HIPK2(+/+)) or stable HIPK2 siRNA interference (siHIPK2) to investigate in vitro whether HIPK2 influenced cell death in glucose restriction. We found that glucose starvation induced cell death, mainly due to c-Jun NH2-terminal kinase activation, in HIPK2(+/+)cells compared with siHIPK2 cells that did not die. (1)H-nuclear magnetic resonance quantitative metabolic analyses showed a marked glycolytic activation in siHIPK2 cells. However, treatment with glycolysis inhibitor 2-deoxy-D-glucose induced cell death only in HIPK2(+/+) cells but not in siHIPK2 cells. Similarly, siGlut-1 interference did not re-establish siHIPK2 cell death under glucose restriction, whereas marked cell death was reached only after zinc supplementation, a condition known to reactivate misfolded p53 and inhibit the pseudohypoxic phenotype in this setting. Further siHIPK2 cell death was reached with zinc in combination with autophagy inhibitor. We propose that the metabolic changes acquired by cells after HIPK2 silencing may contribute to induce resistance to cell death in glucose restriction condition, and therefore be directly relevant for tumor progression. Moreover, elimination of such a tolerance might serve as a new strategy for cancer therapy.

  9. An immunoinformatic approach for identification of Trypanosoma cruzi HLA-A2-restricted CD8+ T cell epitopes

    Science.gov (United States)

    Eickhoff, Christopher S; Van Aartsen, Daniel; Terry, Frances E; Meymandi, Sheba K; Traina, Mahmoud M; Hernandez, Salvador; Martin, William D; Moise, Leonard; De Groot, Annie S; Hoft, Daniel F

    2015-01-01

    Chagas disease is a major neglected tropical disease caused by persistent chronic infection with the protozoan parasite Trypanosoma cruzi. An estimated 8 million people are infected with T. cruzi, however only 2 drugs are approved for treatment and no vaccines are available. Thus there is an urgent need to develop vaccines and new drugs to prevent and treat Chagas disease. In this work, we identify T cell targets relevant for human infection with T. cruzi. The trans-sialidase (TS) gene family is a large family of homologous genes within the T. cruzi genome encoding over 1,400 members. There are 12 highly conserved TS gene family members which encode enzymatically active TS (functional TS; F-TS), while the remaining TS family genes are less conserved, enzymatically inactive and have been hypothesized to be involved in immune evasion (non-functional TS; NF-TS). We utilized immunoinformatic tools to identify HLA-A2-restricted CD8+ T cell epitopes conserved within F-TS family members and NF-TS gene family members. We also utilized a whole-genome approach to identify T cell epitopes present within genes which have previously been shown to be expressed in life stages relevant for human infection (Non-TS genes). Thirty immunogenic HLA-A2-restricted CD8+ T cell epitopes were identified using IFN-γ ELISPOT assays after vaccination of humanized HLA-A2 transgenic mice with mature dendritic cells pulsed with F-TS, NF-TS, and Non-TS peptide pools. The immunogenic HLA-A2-restricted T cell epitopes identified in this work may serve as potential components of an epitope-based T cell targeted vaccine for Chagas disease. PMID:26107442

  10. Measurement of the bystander intervention model for bullying and sexual harassment.

    Science.gov (United States)

    Nickerson, Amanda B; Aloe, Ariel M; Livingston, Jennifer A; Feeley, Thomas Hugh

    2014-06-01

    Although peer bystanders can exacerbate or prevent bullying and sexual harassment, research has been hindered by the absence of a validated assessment tool to measure the process and sequential steps of the bystander intervention model. A measure was developed based on the five steps of Latané and Darley's (1970) bystander intervention model applied to bullying and sexual harassment. Confirmatory factor analysis with a sample of 562 secondary school students confirmed the five-factor structure of the measure. Structural equation modeling revealed that all the steps were influenced by the previous step in the model, as the theory proposed. In addition, the bystander intervention measure was positively correlated with empathy, attitudes toward bullying and sexual harassment, and awareness of bullying and sexual harassment facts. This measure can be used for future research and to inform intervention efforts related to the process of bystander intervention for bullying and sexual harassment.

  11. Adolescent bystanders' perspectives of aggression in the online versus school environments.

    Science.gov (United States)

    Patterson, Lisa J; Allan, Alfred; Cross, Donna

    2016-06-01

    Researchers' understanding of bystanders' perspectives in the cyber-environment fails to take young people's perceptions into account and remains imperfect. Interventions encouraging adolescents to help targets of cyber-aggression are therefore typically based upon traditional school-based aggression research. Twenty-four in-depth interviews with Australian 13-16 year-olds revealed two themes that reflect how young bystanders perceive differences between aggression online and at school. The physical presence theme suggests that young bystanders struggle to determine online intentions in the absence of body language, leading to hesitancy in reactions and furthermore make it easier for them to ignore online transgressions and avoid becoming involved. The authority theme indicates young bystanders perceive that, compared to the school environment, the online environment lacks clearly established rules, authority figures and formal reporting mechanisms. These differences indicate that unique strategies should be developed to encourage young bystanders to intervene in cyber-aggression situations.

  12. Liver irradiation causes distal bystander effects in the rat brain and affects animal behaviour.

    Science.gov (United States)

    Kovalchuk, Anna; Mychasiuk, Richelle; Muhammad, Arif; Hossain, Shakhawat; Ilnytskyy, Slava; Ghose, Abhijit; Kirkby, Charles; Ghasroddashti, Esmaeel; Kovalchuk, Olga; Kolb, Bryan

    2016-01-26

    Radiation therapy can not only produce effects on targeted organs, but can also influence shielded bystander organs, such as the brain in targeted liver irradiation. The brain is sensitive to radiation exposure, and irradiation causes significant neuro-cognitive deficits, including deficits in attention, concentration, memory, and executive and visuospatial functions. The mechanisms of their occurrence are not understood, although they may be related to the bystander effects.We analyzed the induction, mechanisms, and behavioural repercussions of bystander effects in the brain upon liver irradiation in a well-established rat model.Here, we show for the first time that bystander effects occur in the prefrontal cortex and hippocampus regions upon liver irradiation, where they manifest as altered gene expression and somewhat increased levels of γH2AX. We also report that bystander effects in the brain are associated with neuroanatomical and behavioural changes, and are more pronounced in females than in males.

  13. Dietary Restriction reduces hippocampal neurogenesis and granule cell neuron density without affecting the density of mossy fibers.

    Science.gov (United States)

    Staples, Miranda C; Fannon-Pavlich, McKenzie J; Mysore, Karthik K; Dutta, Rahul R; Ongjoco, Alexandria T; Quach, Leon W; Kharidia, Khush M; Somkuwar, Sucharita S; Mandyam, Chitra D

    2017-03-08

    The hippocampal formation undergoes significant morphological and functional changes after prolonged caloric and dietary restriction (DR). In this study we tested whether prolonged DR results in deleterious alterations in hippocampal neurogenesis, density of granule cell neurons and mossy fibers, all of which support plasticity in the dentate gyrus. Young adult animals either experienced free access to food (control condition), or every-other-day feeding regimen (DR condition) for 3 months. The number of Ki-67 cells and 28-day old 5-bromo-2'-deoxyuridine (BrdU) cells were quantified in the dorsal and ventral dentate gyrus to determine the effect of DR on cellular proliferation and survival of neural progenitor cells in the anatomically defined regions of the dentate gyrus. The density of granule cell neurons and synaptoporin were also quantified to determine the effect of DR on granule cell neurons and mossy fiber projections in the dentate gyrus. Our results show that DR increases cellular proliferation and concurrently reduces survival of newly born neurons in the ventral dentate gyrus without effecting the number of cells in the dorsal dentate gyrus. DR reduced density of granule cell neurons in the dorsal dentate gyrus. These alterations in the number of granule cell neurons did not affect mossy fiber density in DR animals, which was visualized as no differences in synaptoporin expression. Our findings demonstrate that granule cell neurons in the dentate gyrus are vulnerable to chronic DR and that the reorganization of granule cells in the dentate gyrus subregions is not producing concomitant alterations in dentate gyrus neuronal circuitry with this type of dietary restriction.

  14. Nuclear translocation of Cyclin B1 marks the restriction point for terminal cell cycle exit in G2 phase.

    Science.gov (United States)

    Müllers, Erik; Silva Cascales, Helena; Jaiswal, Himjyot; Saurin, Adrian T; Lindqvist, Arne

    2014-01-01

    Upon DNA damage, cell cycle progression is temporally blocked to avoid propagation of mutations. While transformed cells largely maintain the competence to recover from a cell cycle arrest, untransformed cells past the G1/S transition lose mitotic inducers, and thus the ability to resume cell division. This permanent cell cycle exit depends on p21, p53, and APC/C(Cdh1). However, when and how permanent cell cycle exit occurs remains unclear. Here, we have investigated the cell cycle response to DNA damage in single cells that express Cyclin B1 fused to eYFP at the endogenous locus. We find that upon DNA damage Cyclin B1-eYFP continues to accumulate up to a threshold level, which is reached only in G2 phase. Above this threshold, a p21 and p53-dependent nuclear translocation required for APC/C(Cdh1)-mediated Cyclin B1-eYFP degradation is initiated. Thus, cell cycle exit is decoupled from activation of the DNA damage response in a manner that correlates to Cyclin B1 levels, suggesting that G2 activities directly feed into the decision for cell cycle exit. Once Cyclin B1-eYFP nuclear translocation occurs, checkpoint inhibition can no longer promote mitotic entry or re-expression of mitotic inducers, suggesting that nuclear translocation of Cyclin B1 marks the restriction point for permanent cell cycle exit in G2 phase.

  15. Personal distress and the influence of bystanders on responding to an emergency.

    Science.gov (United States)

    Hortensius, Ruud; Schutter, Dennis J L G; de Gelder, Beatrice

    2016-08-01

    Spontaneous helping behavior during an emergency is influenced by the personality of the onlooker and by social situational factors such as the presence of bystanders. Here, we sought to determine the influences of sympathy, an other-oriented response, and personal distress, a self-oriented response, on the effect of bystanders during an emergency. In four experiments, we investigated whether trait levels of sympathy and personal distress predicted responses to an emergency in the presence of bystanders by using behavioral measures and single-pulse transcranial magnetic stimulation. Sympathy and personal distress were expected to be associated with faster responses to an emergency without bystanders present, but only personal distress would predict slower responses to an emergency with bystanders present. The results of a cued reaction time task showed that people who reported higher levels of personal distress and sympathy responded faster to an emergency without bystanders (Exp. 1). In contrast to our predictions, perspective taking but not personal distress was associated with slower reaction times as the number of bystanders increased during an emergency (Exp. 2). However, the decrease in motor corticospinal excitability, a direct physiological measure of action preparation, with the increase in the number of bystanders was solely predicted by personal distress (Exp. 3). Incorporating cognitive load manipulations during the observation of an emergency suggested that personal distress is linked to an effect of bystanders on reflexive responding to an emergency (Exp. 4). Taken together, these results indicate that the presence of bystanders during an emergency reduces action preparation in people with a disposition to experience personal distress.

  16. Secretion of IFN-γ but Not IL-17 by CD1d-Restricted NKT Cells Enhances Rejection of Skin Grafts Expressing Epithelial Cell-Derived Antigen

    OpenAIRE

    Mattarollo, Stephen R; Yong, Michelle; Tan, Lieven; Frazer, Ian H; Leggatt, Graham R

    2010-01-01

    NKT cells are key regulators of autoimmunity, tumor immune surveillance, and the immune response to pathogens. The role of NKT cells in regulating adaptive immunity to cutaneous Ags is largely unknown. This study explores the role of CD1d-restricted NKT cells in cross-priming of CD8 effector T cells to OVA expressed in epithelial keratinocytes (K5mOVA transgenic mouse). In a skin grafting model, we show that NKT cells enhance the rejection of K5mOVA skin grafts by promoting generation of OVA-...

  17. LACHESIS restricts gametic cell fate in the female gametophyte of Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Rita Gross-Hardt

    2007-03-01

    Full Text Available In flowering plants, the egg and sperm cells form within haploid gametophytes. The female gametophyte of Arabidopsis consists of two gametic cells, the egg cell and the central cell, which are flanked by five accessory cells. Both gametic and accessory cells are vital for fertilization; however, the mechanisms that underlie the formation of accessory versus gametic cell fate are unknown. In a screen for regulators of egg cell fate, we isolated the lachesis (lis mutant which forms supernumerary egg cells. In lis mutants, accessory cells differentiate gametic cell fate, indicating that LIS is involved in a mechanism that prevents accessory cells from adopting gametic cell fate. The temporal and spatial pattern of LIS expression suggests that this mechanism is generated in gametic cells. LIS is homologous to the yeast splicing factor PRP4, indicating that components of the splice apparatus participate in cell fate decisions.

  18. HIPPO pathway members restrict SOX2 to the inner cell mass where it promotes ICM fates in the mouse blastocyst.

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    Eryn Wicklow

    2014-10-01

    Full Text Available Pluripotent epiblast (EPI cells, present in the inner cell mass (ICM of the mouse blastocyst, are progenitors of both embryonic stem (ES cells and the fetus. Discovering how pluripotency genes regulate cell fate decisions in the blastocyst provides a valuable way to understand how pluripotency is normally established. EPI cells are specified by two consecutive cell fate decisions. The first decision segregates ICM from trophectoderm (TE, an extraembryonic cell type. The second decision subdivides ICM into EPI and primitive endoderm (PE, another extraembryonic cell type. Here, we investigate the roles and regulation of the pluripotency gene Sox2 during blastocyst formation. First, we investigate the regulation of Sox2 patterning and show that SOX2 is restricted to ICM progenitors prior to blastocyst formation by members of the HIPPO pathway, independent of CDX2, the TE transcription factor that restricts Oct4 and Nanog to the ICM. Second, we investigate the requirement for Sox2 in cell fate specification during blastocyst formation. We show that neither maternal (M nor zygotic (Z Sox2 is required for blastocyst formation, nor for initial expression of the pluripotency genes Oct4 or Nanog in the ICM. Rather, Z Sox2 initially promotes development of the primitive endoderm (PE non cell-autonomously via FGF4, and then later maintains expression of pluripotency genes in the ICM. The significance of these observations is that 1 ICM and TE genes are spatially patterned in parallel prior to blastocyst formation and 2 both the roles and regulation of Sox2 in the blastocyst are unique compared to other pluripotency factors such as Oct4 or Nanog.

  19. Identification and characterization of H-2d restricted CD4+ T cell epitopes on Lpp20 of Helicobacter pylori

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    Li Yan

    2012-12-01

    Full Text Available Abstract Background Previous investigation has demonstrated that CD4+ T cells play a crucial role in effective immunity against Helicobacter pylori (H.pylori infection. It has been well proved that Lpp20 is one of major protective antigens that induce immune responses after H.pylori invades host. Therefore it is valuable to identify CD4+ T cell epitopes on Lpp20, which is uncharacterized. Methods Putative epitopes of H-2d restricted CD4+ T cell on Lpp20 of H.pylori were predicted by the SYFPEITHI algorithm and then eight hypothetical epitope peptides were synthesized. After BALB/c mice were primed with recombinant Lpp20, splenic CD4+ T cells were isolated and stimulated with synthesized peptides to measure T cell proliferation and MHC restriction. Cytokine profile was determined by ELISA and real-time PCR. Two identified epitopes were used to immunize mice to investigate CD4+ T cell response by flow cytometry. Results Two of eight peptides were able to stimulate CD4+ T cell proliferation and were mapped to residues 83-97aa and 58-72aa on Lpp20 respectively. These two peptides additively stimulated Th1 cells to secrete IFN-γ. The percentage of CD4+ T cell from mice immunized with two identified epitopes respectively was higher than the control group. Conclusion The identification and characterization of two CD4+ T cell epitopes of Lpp20 helps understand the protective immunity of Lpp20 in H.pylori infection and design effective epitope vaccines against H.pylori.

  20. Non-major histocompatibility complex-restricted cytotoxic activity of blood mononuclear cells stimulated with secreted mycobacterial proteins and other mycobacterial antigens

    DEFF Research Database (Denmark)

    Ravn, P; Pedersen, B K

    1994-01-01

    Several observations indicate that non-major histocompatibility complex (MHC)-restricted cytotoxicity, mediated for example by natural killer cells and lymphokine-activated killer cells, may serve as an important antimicrobial defense mechanism. The purpose of the present study was to investigate...... the influences of different mycobacterial antigens on non-MHC-restricted cytotoxicity and further to investigate the ways by which various lymphocyte subpopulations contribute to the development of this cytotoxicity. Non-MHC-restricted cytotoxicity was induced following stimulation of mononuclear cells......+ cells proliferated and expressed interleukin-2 receptors following stimulation with mycobacterial antigens. Depletion studies after antigen stimulation showed that the cytotoxic effector cells were CD16+ CD56+ and CD4-; the CD4+ cells alone did not mediate non-MHC-restricted cytotoxicity. To evaluate...

  1. Pharmacokinetics and the bystander effect in CD::UPRT/5-FC bi-gene therapy of glioma

    Institute of Scientific and Technical Information of China (English)

    SHI De-zhi; HU Wei-xing; LI Li-xin; CHEN Gong; WEI Dong; GU Pei-yuan

    2009-01-01

    Background Cytosine deaminase (CD) converts 5-fluorocytosine (5-FC) to 5-fluorouracil (5-FU) in CD/5-FC gene therapy, 5-FU will be mostly converted into nontoxic β-alanine without uracil phosphoribosyltransferase (UPRT). UPRT catalyzes the conversion of 5-FU to 5-fluorouridine monophosphate, which directly kills CD::UPRT-expressing ceils and surrounding cells via the bystander effect. But the pharmacokinetics and the bystander effect of CD::UPRT/5-FC has not been verified in vivo and in vitro. Before the CD::UPRT/5-FC bi-gene therapy system is used in clinical trial, it is essential to monitor the transgene expression and function in vivo. Thus, we developed a preclinical tumor model to investigate the feasibility of using 19F-magnetic resonance spectroscopy (19F-MRS) and optical imaging to measure non-invasive CD and UPRT expression and its bystander effect.Methods C6 and C6-CD::UPRT cells were cultured with 5-FC. The medium, cells and their mixture were analyzed by 19F-MRS. Rats with intracranial xenografted encephalic C6-CD::UPRT glioma were injected intraperitoneally with 5-FC and their 19F-MRS spectra recorded. Then the pharmacokinetics of 5-FC was proved. Mixtures of C6 and C6-CD::UPRT cells at different ratios were cultured with 5-FC and the cytotoxic efficacy and survival rate of cells recorded. To determine the mechanism of the bystander effect, the culture media from cell comprising 25% and 75% C6-CD::UPRT cells were examined by19F-MRS. A comparative study of mean was performed using analysis of variance (ANOVA). Results 19F-MRS on samples from C6-CD::UPRT cells cultured with 5-FC showed three broad resonance signals corresponding to 5-FC, 5-FU and fluorinated nucleotides (F-Nuctd). For the C6 mixture, only the 5-FC peak was detected. In vivo serial 19F-MRS spectra showed a strong 5-FC peak and a weak 5-FU peak at 20 minutes after 5-FC injection. The 5-FU concentration reached a maximum at about 50 minutes. The F-Nuctd signal appeared after about I hour

  2. The extended family of CD1d-restricted T cells: sifting through a mixed bag of TCRs, antigens and functions

    Directory of Open Access Journals (Sweden)

    Elodie eMacho-Fernandez

    2015-07-01

    Full Text Available Natural killer T (NKT cells comprise a family of specialized T cells that recognize lipid antigens presented by CD1d. Based on their T cell receptor (TCR usage and antigen-specificities, CD1d-restricted NKT cells have been divided into two main subsets: type I NKT cells that use a canonical invariant TCR α-chain and recognize α-galactosylceramide (α-GalCer, and type II NKT cells that use a more diverse αβ TCR repertoire and do not recognize α-GalCer. In addition, α-GalCer-reactive NKT cells that use non-canonical αβ TCRs and CD1d-restricted T cells that use γδ or δ/αβ TCRs have recently been identified, revealing further diversity among CD1d-restricted T cells. Importantly, in addition to their distinct antigen specificities, functional differences are beginning to emerge between the different members of the CD1d-restricted T cell family. In this review, while using type I NKT cells as comparison, we will focus on type II NKT cells and the other non-invariant CD1d-restricted T cell subsets, and discuss our current understanding of the antigens they recognize, the formation of stimulatory CD1d/antigen complexes, the modes of TCR-mediated antigen recognition, and the mechanisms and consequences of their activation that underlie their function in antimicrobial responses, antitumor immunity, and autoimmunity.

  3. A novel lymphoid progenitor cell population (LSK(low)) is restricted by p18(INK4c).

    Science.gov (United States)

    Dong, Fang; Hao, Sha; Ma, Shihui; Cheng, Hui; Wang, Yajie; Zhou, Wen; Yuan, Weiping; Ema, Hideo; Cheng, Tao

    2016-09-01

    The cyclin-dependent kinase inhibitor CDKN2C (p18(INK4c)) restrains self-renewal in hematopoietic stem cells (HSCs) and participates in the development and maturation of lymphoid cells. Deficiency in p18 predisposes mice and humans to hematopoietic lymphoid malignancies such as T-cell leukemia and multiple myeloma. However, the mechanism by which p18 regulates differentiation from HSCs to lymphoid cells is poorly understood. In this study, we found that a progenitor population characterized by its expression of surface markers, Lin(-) Sca-1(+) c-Kit(low) (LSK(low)), was markedly expanded in the bone marrow of p18 knock-out (p18(-/-)) mice. This novel population possessed lymphoid differentiation potential, but not myeloid differentiation potential, both in vitro and in vivo. Whereas LSK(low) cells and common lymphoid progenitors (CLPs) overlapped functionally in generating lymphoid cells, they were distinct cell populations, because they had different gene expression profiles. Unlike CLPs, LSK(low) cells did not express the interleukin-7 receptor. LSK(low) cells were derived from HSCs and were independent of the p18-deleted microenvironment. This cell population may represent a previously unappreciated transitional stage from HSCs to lymphoid progenitors that is strictly restricted by p18 under physiological conditions. Likewise, LSK(low) might serve as a new cellular target of lymphoid malignances in the absence of p18.

  4. Anti-liver cancer activity of TNF-related apoptosis-inducing ligand gene and its bystander effects

    Institute of Scientific and Technical Information of China (English)

    Chao He; Wei-Feng Lao; Xiao-Tong Hu; Xiang-Ming Xu; Jing Xu; Bing-Liang Fang

    2004-01-01

    AIM: To observe the anti-liver cancer activity of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene and its bystander effects on hepatocellular carcinoma (HCC) cell line SMMC7721.METHODS: Full-length cDNA of human TRAIL was transferred into SMMC7721 cells with a binary adenoviral vector system.Polymerase-chain reaction following reverse transcription (RT-PCR) was used to determine the expression of TRAIL gene. Effects of the transfected gene on proliferation of SMMC7721 cells were measured by MTT assay. Its influence on apoptosis was demonstrated by fluorescence-activated cell sorting (FACS). The bystander effect was observed by co-culturing the SMNC7721 cells with and without the transfected TRAIL gene at different ratios, and the culture medium supernatant from the transfected cells was also examined for its influence on SMMC7721 cells.RESULTS: The growth-inhibition rate and apoptotic cell fraction in the cells transfected with the TRAIL gene, Bax gene or only LacZ gene were 91.2%, 48.0%, 28.8% and 29.1%, 12.5%, 6.6%, respectively. The growth-inhibition rate of transfection with these three sequences in normal human fibroblasts was 6.1%, 45.5% and 7.6%, respectively,indicating a discriminative inhibition of TRAIL transfection on the cancer cells. In the co-culturing test, addition of the transfected TRAIL to SMMC7721 cells in proportions of 5%,25%, 50%, 75% and 100%, resulted in a growth-inhibition of 15.9%, 67%, 80.2%, 86.4% and 87.7%, respectively.We failed to observe a significant growth-inhibition effect of the culture medium supernatant on SMMC7721 cells.CONCLUSION: TRAIL gene transferred by a binary adenoviral vector system can inhibit proliferation of SMMC7721 cells and induce their apoptosis. A bystander effect was observed,which seemed not to be mediated by soluble factors.

  5. GABA agonist promoted formation of low affinity GABA receptors on cerebellar granule cells is restricted to early development

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, G H; Schousboe, A;

    1988-01-01

    The ability of the GABA receptor agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP) to promote formation of low affinity GABA receptors on cerebellar granule cells was tested using primary cultures of these neurons. Granule cells were exposed to THIP (150 microM) for 6 hr after......, respectively, 4, 7, 10 and 14 days in culture. It was found that THIP treatment of 4- and 7-day-old cultures led to formation of low affinity GABA receptors, whereas such receptors could not be detected after THIP treatment in the older cultures (10 and 14 days) in spite of the fact that these cultured granule...... cells expressed a high density of high affinity GABA receptors. It is concluded that the ability of THIP to promote formation of low affinity GABA receptors on cerebellar granule cells is restricted to an early developmental period....

  6. The development of bystander intentions and social-moral reasoning about intergroup verbal aggression.

    Science.gov (United States)

    Palmer, Sally B; Rutland, Adam; Cameron, Lindsey

    2015-11-01

    A developmental intergroup approach was taken to examine the development of prosocial bystander intentions among children and adolescents. Participants as bystanders (N = 260) aged 8-10 and 13-15 years were presented with scenarios of direct aggression between individuals from different social groups (i.e., intergroup verbal aggression). These situations involved either an ingroup aggressor and an outgroup victim or an outgroup aggressor and an ingroup victim. This study focussed on the role of intergroup factors (group membership, ingroup identification, group norms, and social-moral reasoning) in the development of prosocial bystander intentions. Findings showed that prosocial bystander intentions declined with age. This effect was partially mediated by the ingroup norm to intervene and perceived severity of the verbal aggression. However, a moderated mediation analysis showed that only when the victim was an ingroup member and the aggressor an outgroup member did participants become more likely with age to report prosocial bystander intentions due to increased ingroup identification. Results also showed that younger children focussed on moral concerns and adolescents focussed more on psychological concerns when reasoning about their bystander intention. These novel findings help explain the developmental decline in prosocial bystander intentions from middle childhood into early adolescence when observing direct intergroup aggression.

  7. Risk Factors Associated with Peer Victimization and Bystander Behaviors among Adolescent Students

    Science.gov (United States)

    Huang, Zepeng; Liu, Zhenni; Liu, Xiangxiang; Lv, Laiwen; Zhang, Yan; Ou, Limin; Li, Liping

    2016-01-01

    Despite the prevalence of the phenomena of peer victimization and bystander behaviors, little data has generated to describe their relationships and risk factors. In this paper, a self-administered survey using a cross-sectional cluster-random sampling method in a sample of 5450 participants (2734 girls and 2716 boys) between 4th and 11th grades was conducted at six schools (two primary schools and four middle schools) located in Shantou, China. Self-reported peer victimization, bystander behaviors and information regarding parents’ risky behaviors and individual behavioral factors were collected. Multinomial logistic regression analysis was applied to evaluate risk factors affecting peer victimization and bystander behaviors. The results indicated that urban participants were more likely to become bullying victims but less likely to become passive bystanders. Contrarily, bullying victimization was related to the increasing of passive bystander behaviors. Father drinking and mother smoking as independent factors were risk factors for peer victimization. Participants who were smoking or drinking had a tendency to be involved in both peer victimization and passive bystander behaviors. This study suggested that bystander behaviors, victims’ and parents’ educations play a more important role in peer victimization than previously thought. PMID:27472354

  8. Prosocial Bystander Behavior in Bullying Dynamics: Assessing the Impact of Social Capital.

    Science.gov (United States)

    Evans, Caroline B R; Smokowski, Paul R

    2015-12-01

    Individuals who observe a bullying event, but are not directly involved as a bully or victim, are referred to as bystanders. Prosocial bystanders are those individuals who actively intervene in bullying dynamics to support the victim and this prosocial behavior often ends the bullying. The current study examines how social capital in the form of social support, community engagement, mental health functioning, and positive school experiences and characteristics is associated with the likelihood of engaging in prosocial bystander behavior in a large sample (N = 5752; 51.03% female) of racially/ethnically diverse rural youth. It was hypothesized that social capital would be associated with an increased likelihood of engaging in prosocial bystander behavior. Following multiple imputation, an ordered logistic regression with robust standard errors was run. The hypothesis was partially supported and results indicated that social capital in the form of friend and teacher support, ethnic identity, religious orientation, and future optimism were significantly associated with an increased likelihood of engaging in prosocial bystander behavior. Contrary to the hypothesis, a decreased rate of self-esteem was significantly associated with an increased likelihood of engaging in prosocial bystander behavior. The findings highlight the importance of positive social relationships and community engagement in increasing prosocial bystander behavior and ultimately decreasing school bullying. Implications were discussed.

  9. Distinct glucose lowering and beta cell protective effects of vanadium and food restriction in streptozotocin-diabetes.

    Science.gov (United States)

    Cam, M C; Rodrigues, B; McNeill, J H

    1999-11-01

    Vanadium is an oral insulin-mimetic agent that diminishes hyperglycemia, improves beta-cell insulin store and secretory function, and can reverse the diabetic state chronically after withdrawal from treatment. As food restriction has been reported to enhance insulin sensitivity and reduce insulin demand, we assessed the contribution of a reduced food intake to the glucose lowering and beta-cell protective effects of vanadium. Streptozotocin (STZ)-diabetic rats were untreated (D) or administered vanadyl sulfate in the drinking water (DT) at one week prior to and for 5 weeks following the administration of STZ. An additional group was pair-fed (DP) with an equal amount of food as that consumed by the DT group. Shortly after the induction of diabetes, hyperglycemic D rats demonstrated a significant rise in plasma insulin to levels that initially exceeded that of the controls. This was followed by a steady reduction over several weeks, suggesting a gradual depletion of functional beta-cells. Both vanadium treatment and pair-feeding abolished the insulin hypersecretory response following STZ administration. Glucose lowering was enhanced in DT animals when administered higher concentrations of vanadium, despite no further reduction in food intake, and all DT animals (10/10) were normoglycemic by 5 weeks. Mean pancreatic insulin content in DT rats was improved fourfold and was associated with a greater number of granulated beta-cells. Conversely, food restriction only modestly improved glycemia and the pancreatic insulin store and, unlike DT, DP rats remained highly glucose-intolerant. At 5 weeks of diabetes, fed circulating glucose and insulin levels were strongly correlated (P=0.0002) in the D and DP groups, supporting the notion that glucose lowering with food restriction is dependent on improved plasma insulin levels. A separate correlation was observed in DT animals within a lower range of plasma insulin, suggesting that vanadium, unlike food restriction, reduced

  10. All-trans retinoic acid enhances bystander effect of suicide gene therapy in the treatment of breast cancer.

    Science.gov (United States)

    Kong, Heng; Liu, Xia; Yang, Liucheng; Qi, Ke; Zhang, Haoyun; Zhang, Jingwen; Huang, Zonghai; Wang, Hongxian

    2016-03-01

    All-trans retinoic acid (ATRA) has been shown to enhance the expression of connexin 43 (Cx43) and the bystander effect (BSE) in suicide gene therapy. These in turn improve effects of suicide gene therapies for several tumor types. However, whether ATRA can improve BSE remains unclear in suicide gene therapy for breast cancer. In the present study, MCF-7, human breast cancer cells were treated with ATRA in combination with a VEGFP-TK/CD gene suicide system developed by our group. We found that this combination enhances the efficiency of cell killing and apoptosis of breast cancer by strengthening the BSE in vitro. ATRA also promotes gap junction intercellular communication (GJIC) in MCF-7 cells by upregulation of the connexin 43 mRNA and protein in MCF-7 cells. These results indicate that enhancement of GJIC by ATRA in suicide gene system might serve as an attractive and cost-effective strategy of therapy for breast cancer cells.

  11. T-cell responses associated with neonatal alloimmune thrombocytopenia: isolation of HPA-1a-specific, HLA-DRB3*0101-restricted CD4+ T cells.

    Science.gov (United States)

    Ahlen, Maria Therese; Husebekk, Anne; Killie, Mette Kjaer; Skogen, Bjørn; Stuge, Tor B

    2009-04-16

    T-cell responses have been implicated in the development of HPA-1a-induced neonatal alloimmune thrombocytopenia (NAIT). However, HPA-1a-specific T cells have neither been isolated nor characterized. Here, we aimed to determine whether HPA-1a-specific T cells could be isolated from HPA-1a-immunized women. In the present study, peripheral blood mononuclear cells (PBMCs) from an HPA-1a-alloimmunized woman were cultured for weeks in the presence of HPA-1a peptide, labeled with CFSE, and assayed for antigen-specific proliferation. Individual proliferating cells were isolated by fluorescence-activated cell sorting and expanded in culture. Antigen specificity and HLA restriction were determined by cytokine secretion (enzyme-linked immunospot [ELISPOT]) and proliferation assays. Several CD3(+)CD4(+) T-cell clones were isolated that proliferated and secreted cytokines in response to HPA-1a peptide. Two of these clones have been established in long-term culture in our laboratory. Both of these recognize synthetic as well as naturally processed HPA-1a antigen, and the recognition is restricted by the MHC molecule HLA-DRB3*0101 that is strongly associated with NAIT. These HPA-1a-specific T-cell clones represent unambiguous evidence for the association of T-cell responses with NAIT, and they will serve as unique tools to elucidate the cellular immune response that may result in NAIT.

  12. Restricted mobility of specific functional groups reduces anti-cancer drug activity in healthy cells

    DEFF Research Database (Denmark)

    Longo Martins, Murillo; Ignazzi, Rosanna; Eckert, Juergen;

    2016-01-01

    The most common cancer treatments currently available are radio- and chemo-therapy. These therapies have, however, drawbacks, such as, the reduction in quality of life and the low efficiency of radiotherapy in cases of multiple metastases. To lessen these effects, we have encapsulated an anti...... with reduced clearance rate and toxicity. X-rays and neutrons were used to investigate the carrier structure, as well as to assess the drug mobility within the bio-nanocomposite. From these unique data we show that partial mobility restriction of active groups of the drug molecule suggests why this carrier...

  13. The effect of aging and caloric restriction on murine CD8+ T cell chemokine receptor gene expression

    Directory of Open Access Journals (Sweden)

    Mo RuRan

    2007-11-01

    Full Text Available Abstract Background The mechanism explaining the increased disease susceptibility in aging is not well understood. CD8+ T cells are crucial in anti-viral and anti-tumor responses. Although the chemokine system plays a critical role in CD8+ T cell function, very little is known about the relationship between aging and the T cell chemokine system. Results In this study we have examined the effect of aging on murine CD8+ T cell chemokine receptor gene expression. Freshly isolated splenic CD8+ T cells from old C57BL/6 mice were found to have higher CCR1, CCR2, CCR4, CCR5 and CXCR5, and lower CCR7 gene expression compared to their younger cohort. Anti-CD3/anti-CD28 stimulation elicited a similar robust chemokine receptor response from young and old CD8+ T cells. Western blot analyses confirmed elevated protein level of CCR4 and CCR5 in aged CD8+ T cells. Increases in T cell CCR1 and CCR5 expression also correlate to increased in vitro chemotaxis response to macrophage-inflammatory protein-1 α(MIP-1α. Finally, caloric restriction selectively prevents the loss of CD8+ T cell CCR7 gene expression in aging to the level that is seen in young CD8+ T cells. Conclusion These findings are consistent with the notion that aging exists in a state of low grade pro-inflammatory environment. In addition, our results provide a potential mechanism for the reported aging-associated impaired T cell lymphoid homing and allograft response, and reduced survival in sepsis.

  14. T cells detect intracellular DNA but fail to induce type I IFN responses: implications for restriction of HIV replication.

    Directory of Open Access Journals (Sweden)

    Randi K Berg

    Full Text Available HIV infects key cell types of the immune system, most notably macrophages and CD4+ T cells. Whereas macrophages represent an important viral reservoir, activated CD4+ T cells are the most permissive cell types supporting high levels of viral replication. In recent years, it has been appreciated that the innate immune system plays an important role in controlling HIV replication, e.g. via interferon (IFN-inducible restriction factors. Moreover, innate immune responses are involved in driving chronic immune activation and the pathogenesis of progressive immunodeficiency. Several pattern recognition receptors detecting HIV have been reported, including Toll-like receptor 7 and Retinoic-inducible gene-I, which detects viral RNA. Here we report that human primary T cells fail to induce strong IFN responses, despite the fact that this cell type does express key molecules involved in DNA signaling pathways. We demonstrate that the DNA sensor IFI16 migrates to sites of foreign DNA localization in the cytoplasm and recruits the signaling molecules stimulator of IFN genes and Tank-binding kinase, but this does not result in expression of IFN and IFN-stimulated genes. Importantly, we show that cytosolic DNA fails to affect HIV replication. However, exogenous treatment of activated T cells with type I IFN has the capacity to induce expression of IFN-stimulated genes and suppress HIV replication. Our data suggest the existence of an impaired DNA signaling machinery in T cells, which may prevent this cell type from activating cell-autonomous anti-HIV responses. This phenomenon could contribute to the high permissiveness of CD4+ T cells for HIV-1.

  15. Identification and localization of minimal MHC-restricted CD8+ T cell epitopes within the Plasmodium falciparum AMA1 protein

    Directory of Open Access Journals (Sweden)

    Sedegah Martha

    2010-08-01

    Full Text Available Abstract Background Plasmodium falciparum apical membrane antigen-1 (AMA1 is a leading malaria vaccine candidate antigen that is expressed by sporozoite, liver and blood stage parasites. Since CD8+ T cell responses have been implicated in protection against pre-erythrocytic stage malaria, this study was designed to identify MHC class I-restricted epitopes within AMA1. Methods A recombinant adenovirus serotype 5 vector expressing P. falciparum AMA1 was highly immunogenic when administered to healthy, malaria-naive adult volunteers as determined by IFN-γ ELISpot responses to peptide pools containing overlapping 15-mer peptides spanning full-length AMA1. Computerized algorithms (NetMHC software were used to predict minimal MHC-restricted 8-10-mer epitope sequences within AMA1 15-mer peptides active in ELISpot. A subset of epitopes was synthesized and tested for induction of CD8+ T cell IFN-γ responses by ELISpot depletion and ICS assays. A 3-dimensional model combining Domains I + II of P. falciparum AMA1 and Domain III of P. vivax AMA1 was used to map these epitopes. Results Fourteen 8-10-mer epitopes were predicted to bind to HLA supertypes A01 (3 epitopes, A02 (4 epitopes, B08 (2 epitopes and B44 (5 epitopes. Nine of the 14 predicted epitopes were recognized in ELISpot or ELISpot and ICS assays by one or more volunteers. Depletion of T cell subsets confirmed that these epitopes were CD8+ T cell-dependent. A mixture of the 14 minimal epitopes was capable of recalling CD8+ T cell IFN-γ responses from PBMC of immunized volunteers. Thirteen of the 14 predicted epitopes were polymorphic and the majority localized to the more conserved front surface of the AMA1 model structure. Conclusions This study predicted 14 and confirmed nine MHC class I-restricted CD8+ T cell epitopes on AMA1 recognized in the context of seven HLA alleles. These HLA alleles belong to four HLA supertypes that have a phenotypic frequency between 23% - 100% in different human

  16. Bystanders' Behavior in Cyberbullying Episodes: Active and Passive Patterns in the Context of Personal-Socio-Emotional Factors.

    Science.gov (United States)

    Olenik-Shemesh, Dorit; Heiman, Tali; Eden, Sigal

    2017-01-01

    The present study explored bystanders' behavior in cyberbullying (CB) episodes among children and youth, focusing on active and passive behavior patterns. The study examined prevalence and characteristics of bystanders' behavior following CB episodes, and their active-passive intervention patterns in relation to personal (age, gender) and socio-emotional (self-efficacy, social support, sense of loneliness) factors. Of the 1,094 participants (ages 9-18), 497 (46.4%) reported they were bystanders to CB episodes. Of the bystanders, 55.4% were identified as having a passive pattern of behavior-they did not provide any help to cyber-victims, whereas 44.6% were identified as having an active pattern-helping the cyber-victim. In line with the "bystanders' effect," only 35.6% of the bystanders offered direct help to cyber-victims after witnessing CB. When studying the personal-socio-emotional differences between active and passive bystanders, it was found that the "active bystanders" are more often girls, older, have more social support from significant others, and have lower levels of emotional loneliness than bystanders in the passive group. Differences within the passive and active patterns were studied as well. A logistic regression revealed the unique contribution of each predictor to the probability of being an active bystander. It was found that gender and age predicted the probability of being an active bystander: Girls are more likely than boys, and older bystanders are more likely than younger ones, to choose an active pattern and provide help to cyber-victims. In addition, implications for CB prevention and intervention involvement programs to encourage bystanders to help cyber-victims are discussed.

  17. The microRNA bantam regulates a developmental transition in epithelial cells that restricts sensory dendrite growth.

    Science.gov (United States)

    Jiang, Nan; Soba, Peter; Parker, Edward; Kim, Charles C; Parrish, Jay Z

    2014-07-01

    As animals grow, many early born structures grow by cell expansion rather than cell addition; thus growth of distinct structures must be coordinated to maintain proportionality. This phenomenon is particularly widespread in the nervous system, with dendrite arbors of many neurons expanding in concert with their substrate to sustain connectivity and maintain receptive field coverage as animals grow. After rapidly growing to establish body wall coverage, dendrites of Drosophila class IV dendrite arborization (C4da) neurons grow synchronously with their substrate, the body wall epithelium, providing a system to study how proportionality is maintained during animal growth. Here, we show that the microRNA bantam (ban) ensures coordinated growth of C4da dendrites and the epithelium through regulation of epithelial endoreplication, a modified cell cycle that entails genome amplification without cell division. In Drosophila larvae, epithelial endoreplication leads to progressive changes in dendrite-extracellular matrix (ECM) and dendrite-epithelium contacts, coupling dendrite/substrate expansion and restricting dendrite growth beyond established boundaries. Moreover, changes in epithelial expression of cell adhesion molecules, including the beta-integrin myospheroid (mys), accompany this developmental transition. Finally, endoreplication and the accompanying changes in epithelial mys expression are required to constrain late-stage dendrite growth and structural plasticity. Hence, modulating epithelium-ECM attachment probably influences substrate permissivity for dendrite growth and contributes to the dendrite-substrate coupling that ensures proportional expansion of the two cell types.

  18. Development of a diverse human T-cell repertoire despite stringent restriction of hematopoietic clonality in the thymus.

    Science.gov (United States)

    Brugman, Martijn H; Wiekmeijer, Anna-Sophia; van Eggermond, Marja; Wolvers-Tettero, Ingrid; Langerak, Anton W; de Haas, Edwin F E; Bystrykh, Leonid V; van Rood, Jon J; de Haan, Gerald; Fibbe, Willem E; Staal, Frank J T

    2015-11-03

    The fate and numbers of hematopoietic stem cells (HSC) and their progeny that seed the thymus constitute a fundamental question with important clinical implications. HSC transplantation is often complicated by limited T-cell reconstitution, especially when HSC from umbilical cord blood are used. Attempts to improve immune reconstitution have until now been unsuccessful, underscoring the need for better insight into thymic reconstitution. Here we made use of the NOD-SCID-IL-2Rγ(-/-) xenograft model and lentiviral cellular barcoding of human HSCs to study T-cell development in the thymus at a clonal level. Barcoded HSCs showed robust (>80% human chimerism) and reproducible myeloid and lymphoid engraftment, with T cells arising 12 wk after transplantation. A very limited number of HSC clones (thymus, with further restriction of the number of clones during subsequent development. Nevertheless, T-cell receptor rearrangements were polyclonal and showed a diverse repertoire, demonstrating that a multitude of T-lymphocyte clones can develop from a single HSC clone. Our data imply that intrathymic clonal fitness is important during T-cell development. As a consequence, immune incompetence after HSC transplantation is not related to the transplantation of limited numbers of HSC but to intrathymic events.

  19. Successful transplantation of human hepatic stem cells with restricted localization to liver using hyaluronan grafts.

    Science.gov (United States)

    Turner, Rachael A; Wauthier, Eliane; Lozoya, Oswaldo; McClelland, Randall; Bowsher, James E; Barbier, Claire; Prestwich, Glenn; Hsu, Edward; Gerber, David A; Reid, Lola M

    2013-02-01

    Cell therapies are potential alternatives to organ transplantation for liver failure or dysfunction but are compromised by inefficient engraftment, cell dispersal to ectopic sites, and emboli formation. Grafting strategies have been devised for transplantation of human hepatic stem cells (hHpSCs) embedded into a mix of soluble signals and extracellular matrix biomaterials (hyaluronans, type III collagen, laminin) found in stem cell niches. The hHpSCs maintain a stable stem cell phenotype under the graft conditions. The grafts were transplanted into the livers of immunocompromised murine hosts with and without carbon tetrachloride treatment to assess the effects of quiescent versus injured liver conditions. Grafted cells remained localized to the livers, resulting in a larger bolus of engrafted cells in the host livers under quiescent conditions and with potential for more rapid expansion under injured liver conditions. By contrast, transplantation by direct injection or via a vascular route resulted in inefficient engraftment and cell dispersal to ectopic sites. Transplantation by grafting is proposed as a preferred strategy for cell therapies for solid organs such as the liver.

  20. Heart rate modulation in bystanding geese watching social and non-social events

    NARCIS (Netherlands)

    Wascher, Claudia A. F.; Scheiber, Isabella B. R.; Kotrschal, Kurt

    2008-01-01

    Simply observing other individuals interacting has been shown to affect subsequent behaviour and also hormones in 'bystander' individuals. However, immediate physiological responses of an observer have been hardly investigated. Here we present results on individuals' heart rate (HR) responses during

  1. Effects of manipulated aggressive 'interactions' on bystanding male fighting fish, Betta splendens

    DEFF Research Database (Denmark)

    Peake, Thomas More; Matos, Ricardo Jorge; McGregor, Peter Kenneth

    2006-01-01

    Aggressive interactions between animals often take place in a social environment. Third parties not involved in those interactions, bystanders, have the opportunity to extract information from such interactions and such information may direct their future behaviour towards the interactants. Studi...

  2. Morbidity among bystanders of bullying behavior at school: concepts, concerns, and clinical/research issues.

    Science.gov (United States)

    Rivers, Ian

    2011-11-04

    The role of the bystander is not one that is easily understood in the anti-bullying literature. Roles within the unofficial hierarchy of the school-yard and playground overlap considerably, and each role has its own social dynamic that brings with it a shifting behavioral landscape that affects every student. In this article, the mental health correlates of three categories of bystander are explored: the co-victim, the isolate, and the confederate. Each category of bystander has its own characterizations and mental health correlates. Reports of post-traumatic stress, internalized hostility, substance use, and suicide ideation are discussed with reference to studies involving witnesses of family abuse, community and school violence as well as bullying. It is argued that bystanders are the key to challenging bullying in schools, and their mental health and well-being is pivotal to the effectiveness of anti-bullying interventions.

  3. P44/WDR77 restricts the sensitivity of proliferating cells to TGFβ signaling

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Pengfei [Department of Breast and Thyroid Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Road, Wuhan, Hubei 430022 (China); Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 (United States); Gao, Shen [Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 (United States); Gu, Zhongping [Department of Thoracic Surgery, Tangdu Hospital, Fourth Military Medical University, Xi’an 710038 (China); Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 (United States); Huang, Tao [Department of Breast and Thyroid Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Road, Wuhan, Hubei 430022 (China); Wang, Zhengxin, E-mail: zhenwang@mdanderson.org [Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 (United States)

    2014-07-18

    Highlights: • P44/WDR77 causes proliferating cells to become non-responsive to TGFβ signaling. • P44/WDR77 down-regulates TβRII and TβR2 expression. • P44/WDR77 down-regulated TGFβ signaling correlates with lung tumorigenesis. - Abstract: We previously reported that a novel WD-40 domain-containing protein, p44/WDR77, drives quiescent epithelial cells to re-enter the cell cycle and plays an essential role for growth of lung and prostate cancer cells. Transforming growth factor beta (TGFβ) signaling is important in the maintenance of non-transformed cells in the quiescent or slowly cycling stage. However, both non-transformed proliferating cells and human cancer cells are non-responsive to endogenous TGFβ signaling. The mechanism by which proliferating cells become refractory to TGFβ inhibition is not well established. Here, we found that silencing p44/WDR77 increased cellular sensitivity to TGFβ signaling and that this was inversely correlated with decreased cell proliferation. Smad2 or 3 phosphorylation, TGFβ-mediated transcription, and TGFβ2 and TGFβ receptor type II (TβRII) expression were dramatically induced by silencing of p44/WDR77. These data support the hypothesis that p44/WDR77 down-regulates the expression of the TGFβ ligand and its receptor, thereby leading to a cellular non-response to TGFβ signaling. Finally, we found that p44/WDR77 expression was correlated with cell proliferation and decreased TGFβ signaling during lung tumorigenesis. Together, these results suggest that p44/WDR77 expression causes the non-sensitivity of proliferating cells to TGFβ signaling, thereby contributing to cellular proliferation during lung tumorigenesis.

  4. Giant cell tumor of the tendon sheath restricting joint movement in the thumb: A case study and review of literature

    Directory of Open Access Journals (Sweden)

    Muzaffer Durmus

    2015-04-01

    Full Text Available Giant cell tumors of the tendon sheath are the second most common type of subcutaneous benign tumors found in the hand. These tumors are slow growing soft tissue mases that develop over a long period of time and can occur at any age. Although such lesions are usually painless, there is a possibility of recurrence of the tumor. Patients should seek postoperative management in order to prevent any possibility of recurrence. In view of the current literature, we present a case involving a patient suffering from a multifocal giant cell tumor of the tendon sheath that restricted movement of the interphalangeal joints of the thumb. [Hand Microsurg 2015; 4(1.000: 16-19

  5. A bHLH-Based Feedback Loop Restricts Vascular Cell Proliferation in Plants

    NARCIS (Netherlands)

    Vera-Sirera, Francisco; Rybel, de B.P.M.; Urbez, Cristina; Kouklas, Evangelos; Pesquera, Marta; Alvarez-Mahecha, Juan Camilo; Minguet, Eugenio; Tuominen, Hanneke; Carbonell, Juan; Borst, J.W.; Weijers, D.; Blazquez, Miguel

    2015-01-01

    Control of tissue dimensions in multicellular organisms requires the precise quantitative regulation of mitotic activity. In plants, where cells are immobile,
    tissue size is achieved through control of both cell division orientation and mitotic rate. The bHLH transcription factor heterodimer for

  6. Delineation of Several DR-Restricted Tetanus Toxin T Cell Epitopes

    NARCIS (Netherlands)

    Demotz, Stephane; Lanzavecchia, Antonio; Eisel, Ulrich; Niemann, Heiner; Widmann, Christian; Corradin, Giampietro

    1989-01-01

    We have characterized five human T cell clones specific for tetanus toxin. The combination of different techniques allowed us to precisely map two T cell epitopes within fragments 830-843 and 1273-1284 of tetanus toxin, as formally demonstrated by the use of corresponding synthetic peptides. The thr

  7. Confocal restricted-height imaging of suspension cells (CRISC) in a PDMS microdevice during apoptosis

    NARCIS (Netherlands)

    Munoz-Pinedo, Cristina; Green, Douglas R.; Berg, van den Albert

    2005-01-01

    We have monitored and imaged cell death induced in human leukemic U937 cells over time using three-color confocal imaging. Three different apoptotic inducers, anti-Fas, TNF- and Etoposide were used. Individual cascaded events such as loss of mitochondrial transmembrane potential, exposure of phospha

  8. The Effect of a Class-wide Training on Prosocial Bystander Behaviors

    OpenAIRE

    Barnes, Charity Deanne

    2015-01-01

    The purpose of this study was to decrease school bullying by implementing a class-wide intervention that targets bystanders. Hypotheses include that an intervention will increase prosocial bystander behaviors that will result in reduced rates of bullying and improved positive peer responses. Ross and Horner’s Positive Behavior Supports bullying prevention program was modified to increase incentives for students who defend others from bullying. A multiple baseline design across three general e...

  9. Confocal restricted-height imaging of suspension cells (CRISC) in a PDMS microdevice during apoptosis.

    Science.gov (United States)

    Muñoz-Pinedo, Cristina; Green, Douglas R; van den Berg, Albert

    2005-06-01

    We have monitored and imaged cell death induced in human leukemic U937 cells over time using three-color confocal imaging. Three different apoptotic inducers, anti-Fas, TNF-alpha and Etoposide were used. Individual cascaded events such as loss of mitochondrial transmembrane potential, exposure of phosphatidyl-serine, membrane blebbing and permeabilization of the cell membrane have been observed in real time with different individual cells. From the results, an interesting heterogeneicity in the apoptotic phenotype has been observed. The CRISC method is easy to use and provides biologist with a powerful additional tool to study in real-time processes of several hours of duration such as apoptosis. We predict that the period of cell viability obtained after protein coating of the PDMS devices (>80 h) will also allow monitoring of other biological processes of longer duration or long onset time, such as mitosis, phagocytosis and differentiation.

  10. Restrictions in cell cycle progression of adult vestibular supporting cells in response to ectopic cyclin D1 expression.

    Directory of Open Access Journals (Sweden)

    Heidi Loponen

    Full Text Available Sensory hair cells and supporting cells of the mammalian inner ear are quiescent cells, which do not regenerate. In contrast, non-mammalian supporting cells have the ability to re-enter the cell cycle and produce replacement hair cells. Earlier studies have demonstrated cyclin D1 expression in the developing mouse supporting cells and its downregulation along maturation. In explant cultures of the mouse utricle, we have here focused on the cell cycle control mechanisms and proliferative potential of adult supporting cells. These cells were forced into the cell cycle through adenoviral-mediated cyclin D1 overexpression. Ectopic cyclin D1 triggered robust cell cycle re-entry of supporting cells, accompanied by changes in p27(Kip1 and p21(Cip1 expressions. Main part of cell cycle reactivated supporting cells were DNA damaged and arrested at the G2/M boundary. Only small numbers of mitotic supporting cells and rare cells with signs of two successive replications were found. Ectopic cyclin D1-triggered cell cycle reactivation did not lead to hyperplasia of the sensory epithelium. In addition, a part of ectopic cyclin D1 was sequestered in the cytoplasm, reflecting its ineffective nuclear import. Combined, our data reveal intrinsic barriers that limit proliferative capacity of utricular supporting cells.

  11. Bacterial CD1d-restricted glycolipids induce IL-10 production by human regulatory T cells upon cross-talk with invariant NKT cells.

    Science.gov (United States)

    Venken, Koen; Decruy, Tine; Aspeslagh, Sandrine; Van Calenbergh, Serge; Lambrecht, Bart N; Elewaut, Dirk

    2013-09-01

    Invariant NKT (iNKT) cells and CD4(+)CD25(+)FOXP3(+) regulatory T cells (Tregs) are important immune regulatory T cells with Ag reactivity to glycolipids and peptides, respectively. However, the functional interplay between these cells in humans is poorly understood. We show that Tregs suppress iNKT cell proliferation induced by CD1d-restricted glycolipids, including bacterial-derived diacylglycerols, as well as by innate-like activation. Inhibition was related to the potency of iNKT agonists, making diacylglycerol iNKT responses very prone to suppression. Cytokine production by iNKT cells was differentially modulated by Tregs because IL-4 production was reduced more profoundly compared with IFN-γ. A compelling observation was the significant production of IL-10 by Tregs after cell contact with iNKT cells, in particular in the presence of bacterial diacylglycerols. These iNKT-primed Tregs showed increased FOXP3 expression and superior suppressive function. Suppression of iNKT cell responses, but not conventional T cell responses, was IL-10 dependent, suggesting that there is a clear difference in mechanism between the Treg-mediated inhibition of these cell types. Our data highlight a physiologically relevant interaction between human iNKT and Tregs upon pathogen-derived glycolipid recognition that has a significant impact on the design of iNKT cell-based therapeutics.

  12. Lipid raft association restricts CD44-ezrin interaction and promotion of breast cancer cell migration.

    LENUS (Irish Health Repository)

    Donatello, Simona

    2012-12-01

    Cancer cell migration is an early event in metastasis, the main cause of breast cancer-related deaths. Cholesterol-enriched membrane domains called lipid rafts influence the function of many molecules, including the raft-associated protein CD44. We describe a novel mechanism whereby rafts regulate interactions between CD44 and its binding partner ezrin in migrating breast cancer cells. Specifically, in nonmigrating cells, CD44 and ezrin localized to different membranous compartments: CD44 predominantly in rafts, and ezrin in nonraft compartments. After the induction of migration (either nonspecific or CD44-driven), CD44 affiliation with lipid rafts was decreased. This was accompanied by increased coprecipitation of CD44 and active (threonine-phosphorylated) ezrin-radixin-moesin (ERM) proteins in nonraft compartments and increased colocalization of CD44 with the nonraft protein, transferrin receptor. Pharmacological raft disruption using methyl-β-cyclodextrin also increased CD44-ezrin coprecipitation and colocalization, further suggesting that CD44 interacts with ezrin outside rafts during migration. Conversely, promoting CD44 retention inside lipid rafts by pharmacological inhibition of depalmitoylation virtually abolished CD44-ezrin interactions. However, transient single or double knockdown of flotillin-1 or caveolin-1 was not sufficient to increase cell migration over a short time course, suggesting complex crosstalk mechanisms. We propose a new model for CD44-dependent breast cancer cell migration, where CD44 must relocalize outside lipid rafts to drive cell migration. This could have implications for rafts as pharmacological targets to down-regulate cancer cell migration.

  13. Bystanders' responses to offline bullying and cyberbullying: The role of empathy and normative beliefs about aggression.

    Science.gov (United States)

    Machackova, Hana; Pfetsch, Jan

    2016-04-01

    Cyberbullying often takes place with the virtual presence or knowledge of bystanders. While we have some evidence about the determinants of bystanders' responses to offline bullying, we lack empirical studies concerning the variables that influence bystanders' responses to cyberbullying. The current study examines bystanders' responses to offline bullying and cyberbullying incidents. Two types of responses were captured: support toward the victims and the reinforcement of bullies' actions. Using data from 321 German adolescents (ages 12-18; M = 14.99; 44% girls), the association between bystanders' responses and normative beliefs about verbal aggression and cyberaggression, and affective and cognitive empathy, were tested in a path model. Both types of normative beliefs positively predicted the reinforcement of bullies, and normative belief about verbal aggression also predicted support for the victims of offline bullying. Both types of empathy predicted support in offline bullying, but only affective empathy predicted support in cyberbullying. There was no link between affective or cognitive empathy to the reinforcement of bullies. Moreover, bystanders' tendencies to respond supportively to the victim or to reinforce the bully were rather consistent in both cyber- and offline bullying, but there was no link between support and reinforcement. The findings are discussed with regard to implications for prevention and intervention efforts.

  14. Determinants of self-reported bystander behavior in cyberbullying incidents amongst adolescents.

    Science.gov (United States)

    DeSmet, Ann; Veldeman, Charlene; Poels, Karolien; Bastiaensens, Sara; Van Cleemput, Katrien; Vandebosch, Heidi; De Bourdeaudhuij, Ilse

    2014-04-01

    This study explores behavioral determinants of self-reported cyberbullying bystander behavior from a behavioral change theoretical perspective, to provide levers for interventions. Nine focus groups were conducted with 61 young adolescents (aged 12-16 years, 52% girls). Assertive defending, reporting to others, providing advice, and seeking support were the most mentioned behaviors. Self-reported bystander behavior heavily depended on contextual factors, and should not be considered a fixed participant role. Bystanders preferred to handle cyberbullying offline and in person, and comforting the victim was considered more feasible than facing the bully. Most prevailing behavioral determinants to defend or support the victim were low moral disengagement, that the victim is an ingroup member, and that the bystander is popular. Youngsters felt they received little encouragement from their environment to perform positive bystanding behavior, since peers have a high acceptance for not defending and perceived parental support for defending behavior is largely lacking. These results suggest multilevel models for cyberbullying research, and interventions are needed. With much previous research into cyberbullying insufficiently founded in theoretical models, the employed framework of the Integrative Model and Social Cognitive Theory may inspire future studies into bystander behavior.

  15. Identification of a dengue virus-specific HLA-A*0201-restricted CD8+ T cell epitope.

    Science.gov (United States)

    Wen, Jinsheng; Duan, Zhiliang; Jiang, Lifang

    2010-04-01

    In this study, a combination of epitope-prediction programs and in vitro assays was used to identify dengue virus (DENV)-specific CD8(+) T cell epitopes. Peripheral blood mononuclear cells (PBMCs) isolated from patients who recovered from dengue fever were stimulated with candidate epitope peptides derived from DENV, which were predicted by using SYFPEITHI and RANKpep epitope-prediction programs. The IFN-gamma ELISpot results and the results of intracellular staining of IFN-gamma showed that peptides NS4b_40 (TLYAVATTI), E_256 (QEGAMHTAL), NS3_205 (LPAIVREAI), NS5_210 (SRNSTHEMY), and NS3_207 (AIVREAIKR) could induce the recall response of CD8(+) T cells. Furthermore, the results of the MHC-peptide complex stabilization assay revealed that peptide NS4b_40 (TLYAVATTI) has a high affinity for HLA-A*0201 molecules. The IFN-gamma ELISpot results and staining of intracellular IFN-gamma confirmed that this peptide could induce high-level CD8(+) T cell response in HLA-A*0201 positive PBMCs. Peptide NS4b_40 (TLYAVATTI) was identified as a novel DENV-specific HLA-A*0201-restricted CD8(+) T cell epitope.

  16. A conserved chromatin architecture marks and maintains the restricted germ cell lineage in worms and flies.

    Science.gov (United States)

    Schaner, Christine E; Deshpande, Girish; Schedl, Paul D; Kelly, William G

    2003-11-01

    In C. elegans, mRNA production is initially repressed in the embryonic germline by a protein unique to C. elegans germ cells, PIE-1. PIE-1 is degraded upon the birth of the germ cell precursors, Z2 and Z3. We have identified a chromatin-based mechanism that succeeds PIE-1 repression in these cells. A subset of nucleosomal histone modifications, methylated lysine 4 on histone H3 (H3meK4) and acetylated lysine 8 on histone H4 (H4acetylK8), are globally lost and the DNA appears more condensed. This coincides with PIE-1 degradation and requires that germline identity is not disrupted. Drosophila pole cell chromatin also lacks H3meK4, indicating that a unique chromatin architecture is a conserved feature of embryonic germ cells. Regulation of the germline-specific chromatin architecture requires functional nanos activity in both organisms. These results indicate that genome-wide repression via a nanos-regulated, germ cell-specific chromatin organization is a conserved feature of germline maintenance during embryogenesis.

  17. A1 demonstrates restricted tissue distribution during embryonic development and functions to protect against cell death.

    Science.gov (United States)

    Carrió, R.; López-Hoyos, M.; Jimeno, J.; Benedict, M. A.; Merino, R.; Benito, A.; Fernández-Luna, J. L.; Núñez, G.; García-Porrero, J. A.; Merino, J.

    1996-01-01

    Members of the bcl-2 gene family are essential regulators of cell survival in a wide range of biological processes. A1, a member of the family, is known to be expressed in certain adult tissues. However, the precise tissue distribution and function of A1 remains poorly understood. We show here that A1 is expressed in multiple tissues during murine embryonic development. In the embryo, A1 was detected first at embryonic day 11.5 in liver, brain, and limbs. At day 13.5 of gestation, A1 expression was observed in the central nervous system, liver, perichondrium, and digital zones of developing limbs in a pattern different from that of bcl-X. In the central nervous system of 15.5-day embryos, A1 was expressed at high levels in the ventricular zone and cortical plate of brain cortex. Significantly, the interdigital zones of limbs and the intermediate region of the developing brain cortex, two sites associated with extensive cell death, were devoid of A1 and bcl-X. The expression of A1 was retained in many adult tissues. To assess the ability of A1 to modulate cell death, stable transfectants expressing different amounts of A1 protein were generated in K562 cells. Expression of A1 was associated with retardation of apoptotic cell death induced by actinomycin D and cycloheximide as well as by okadaic acid. Confocal microscopy showed that the A1 protein was localized to the cytoplasm in a pattern similar to that of Bcl-2. These results demonstrate that the expression of A1 is wider than previously reported in adult tissues. Furthermore, its distribution in multiple tissues of the embryo suggests that A1 plays a role in the regulation of physiological cell death during embryonic development. Images Figure 1 Figure 2 Figure 3 Figure 5 PMID:8952545

  18. Ablation of STAT3 in the B Cell Compartment Restricts Gammaherpesvirus Latency In Vivo

    Science.gov (United States)

    Reddy, Sandeep Steven; Foreman, Hui-Chen Chang; Sioux, Thubten Ozula; Park, Gee Ho; Poli, Valeria; Reich, Nancy C.

    2016-01-01

    ABSTRACT A challenging property of gammaherpesviruses is their ability to establish lifelong persistence. The establishment of latency in B cells is thought to involve active virus engagement of host signaling pathways. Pathogenic effects of these viruses during latency or following reactivation can be devastating to the host. Many cancers, including those associated with members of the gammaherpesvirus family, Kaposi’s sarcoma-associated herpesvirus and Epstein-Barr virus, express elevated levels of active host signal transducer and activator of transcription-3 (STAT3). STAT3 is activated by tyrosine phosphorylation in response to many cytokines and can orchestrate effector responses that include proliferation, inflammation, metastasis, and developmental programming. However, the contribution of STAT3 to gammaherpesvirus pathogenesis remains to be completely understood. This is the first study to have identified STAT3 as a critical host determinant of the ability of gammaherpesvirus to establish long-term latency in an animal model of disease. Following an acute infection, murine gammaherpesvirus 68 (MHV68) established latency in resident B cells, but establishment of latency was dramatically reduced in animals with a B cell-specific STAT3 deletion. The lack of STAT3 in B cells did not impair germinal center responses for immunoglobulin (Ig) class switching in the spleen and did not reduce either total or virus-specific IgG titers. Although ablation of STAT3 in B cells did not have a global effect on these assays of B cell function, it had long-term consequences for the viral load of the host, since virus latency was reduced at 6 to 8 weeks postinfection. Our findings establish host STAT3 as a mediator of gammaherpesvirus persistence. PMID:27486189

  19. Drosophila Pez acts in Hippo signaling to restrict intestinal stem cell proliferation

    DEFF Research Database (Denmark)

    Poernbacher, Ingrid; Baumgartner, Roland; Marada, Suresh K;

    2012-01-01

    The conserved Hippo signaling pathway acts in growth control and is fundamental to animal development and oncogenesis. Hippo signaling has also been implicated in adult midgut homeostasis in Drosophila. Regulated divisions of intestinal stem cells (ISCs), giving rise to an ISC and an enteroblast...... (EB) that differentiates into an enterocyte (EC) or an enteroendocrine (EE) cell, enable rapid tissue turnover in response to intestinal stress. The damage-related increase in ISC proliferation requires deactivation of the Hippo pathway and consequential activation of the transcriptional coactivator...

  20. Dietary restriction and fasting arrest B and T cell development and increase mature B and T cell numbers in bone marrow.

    Science.gov (United States)

    Shushimita, Shushimita; de Bruijn, Marjolein J W; de Bruin, Ron W F; IJzermans, Jan N M; Hendriks, Rudi W; Dor, Frank J M F

    2014-01-01

    Dietary restriction (DR) delays ageing and extends life span. Both long- and short-term DR, as well as short-term fasting provide robust protection against many "neuronal and surgery related damaging phenomena" such as Parkinson's disease and ischemia-reperfusion injury. The exact mechanism behind this phenomenon has not yet been elucidated. Its anti-inflammatory actions prompted us to thoroughly investigate the consequences of DR and fasting on B and T cell compartments in primary and secondary lymphoid organs of male C57Bl/6 mice. In BM we found that DR and fasting cause a decrease in the total B cell population and arrest early B cell development, while increasing the number of recirculating mature B cells. In the fasting group, a significant reduction in peripheral B cell counts was observed in both spleen and mesenteric lymph nodes (mLN). Thymopoiesis was arrested significantly at double negative DN2 stage due to fasting, whereas DR resulted in a partial arrest of thymocyte development at the DN4 stage. Mature CD3(+) T cell populations were increased in BM and decreased in both spleen and mLN. Thus, DR arrests B cell development in the BM but increases the number of recirculating mature B cells. DR also arrests maturation of T cells in thymus, resulting in depletion of mature T cells from spleen and mLN while recruiting them to the BM. The functional relevance in relation to protection against organ damage needs to be determined.

  1. Dietary restriction and fasting arrest B and T cell development and increase mature B and T cell numbers in bone marrow.

    Directory of Open Access Journals (Sweden)

    Shushimita Shushimita

    Full Text Available Dietary restriction (DR delays ageing and extends life span. Both long- and short-term DR, as well as short-term fasting provide robust protection against many "neuronal and surgery related damaging phenomena" such as Parkinson's disease and ischemia-reperfusion injury. The exact mechanism behind this phenomenon has not yet been elucidated. Its anti-inflammatory actions prompted us to thoroughly investigate the consequences of DR and fasting on B and T cell compartments in primary and secondary lymphoid organs of male C57Bl/6 mice. In BM we found that DR and fasting cause a decrease in the total B cell population and arrest early B cell development, while increasing the number of recirculating mature B cells. In the fasting group, a significant reduction in peripheral B cell counts was observed in both spleen and mesenteric lymph nodes (mLN. Thymopoiesis was arrested significantly at double negative DN2 stage due to fasting, whereas DR resulted in a partial arrest of thymocyte development at the DN4 stage. Mature CD3(+ T cell populations were increased in BM and decreased in both spleen and mLN. Thus, DR arrests B cell development in the BM but increases the number of recirculating mature B cells. DR also arrests maturation of T cells in thymus, resulting in depletion of mature T cells from spleen and mLN while recruiting them to the BM. The functional relevance in relation to protection against organ damage needs to be determined.

  2. A multidirectional non-cell autonomous control and a genetic interaction restricting tobacco etch virus susceptibility in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Suresh Gopalan

    Full Text Available BACKGROUND: Viruses constitute a major class of pathogens that infect a variety of hosts. Understanding the intricacies of signaling during host-virus interactions should aid in designing disease prevention strategies and in understanding mechanistic aspects of host and pathogen signaling machinery. METHODOLOGY/PRINCIPAL FINDINGS: An Arabidopsis mutant, B149, impaired in susceptibility to Tobacco etch virus (TEV, a positive strand RNA virus of picoRNA family, was identified using a high-throughput genetic screen and a counterselection scheme. The defects include initiation of infection foci, rate of cell-to-cell movement and long distance movement. CONCLUSIONS/SIGNIFICANCE: The defect in infectivity is conferred by a recessive locus. Molecular genetic analysis and complementation analysis with three alleles of a previously published mutant lsp1 (loss of susceptibility to potyviruses indicate a genetic interaction conferring haploinsufficiency between the B149 locus and certain alleles of lsp1 resulting in impaired host susceptibility. The pattern of restriction of TEV foci on leaves at or near the boundaries of certain cell types and leaf boundaries suggest dysregulation of a multidirectional non-cell autonomous regulatory mechanism. Understanding the nature of this multidirectional signal and the molecular genetic mechanism conferring it should potentially reveal a novel arsenal in the cellular machinery.

  3. Variability: The common factor linking low dose-induced genomic instability, adaptation and bystander effects

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Jeffrey L. [Department of Radiation Oncology, University of Washington Medical Center, 1959 NE Pacific, Box 356069, Seattle, WA 98195-6069 (United States)]. E-mail: jschwart@u.washington.edu

    2007-03-01

    The characteristics of low dose radiation-induced genomic instability, adaptive responses, and bystander effects were compared in order to probe possible underlying mechanisms, and develop models for predicting response to in vivo low dose radiation exposures. While there are some features that are common to all three (e.g., absence of a true dose-response, the multiple endpoints affected by each), other characteristics appear to distinguish one from the other (e.g., TP53 involvement, LET response, influence of DNA repair). Each of the responses is also highly variable; not all cell and tissue models show the same response and there is much interindividual variation in response. Most of these studies have employed in vitro cell culture or tissue explant models, and understanding underlying mechanisms and the biological significance of these low dose-responses will require study of tissue-specific in vivo endpoints. The in vitro studies strongly suggest that modeling low dose radiation effects will be a complex process, and will likely require separate study of each of these low dose phenomena. Knowledge of instability responses, for example, may not aid in predicting other low dose effects in the same tissue.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. ERG promotes the maintenance of hematopoietic stem cells by restricting their differentiation

    DEFF Research Database (Denmark)

    Knudsen, Kasper Jermiin; Rehn, Matilda Carolina; Hasemann, Marie Sigurd;

    2015-01-01

    The balance between self-renewal and differentiation is crucial for the maintenance of hematopoietic stem cells (HSCs). Whereas numerous gene regulatory factors have been shown to control HSC self-renewal or drive their differentiation, we have relatively few insights into transcription factors...

  6. Extra-Low-Frequency Magnetic Fields alter Cancer Cells through Metabolic Restriction

    CERN Document Server

    Li, Ying

    2012-01-01

    Background: Biological effects of extra-low-frequency (ELF) magnetic fields (MF) have lacked a credible mechanism of interaction between MFs and living material. Objectives: Examine the effect of ELF-MFs on cancer cells. Methods: Five cancer cell lines were exposed to ELF-MFs within the range of 0.025 to 5 microT, and the cells were examined for karyotype changes after 6 days. Results: All cancer cells lines lost chromosomes from MF exposure, with a mostly flat dose-response. Constant MF exposures for three weeks allow a rising return to the baseline, unperturbed karyotypes. From this point, small MF increases or decreases are again capable of inducing karyotype contractions. Our data suggests that the karyotype contractions are caused by MF interference with mitochondria's ATP synthase (ATPS), compensated by the action of AMP-activated Protein Kinase (AMPK). The effects of MFs are similar to those of the ATPS inhibitor oligomycin. They are amplified by metformin, an AMPK stimulator, and attenuated by resisti...

  7. XIAP Restricts TNF- and RIP3-Dependent Cell Death and Inflammasome Activation

    DEFF Research Database (Denmark)

    Yabal, Monica; Müller, Nicole; Adler, Heiko;

    2014-01-01

    X-linked inhibitor of apoptosis protein (XIAP) has been identified as a potent regulator of innate immune responses, and loss-of-function mutations in XIAP cause the development of the X-linked lymphoproliferative syndrome type 2 (XLP-2) in humans. Using gene-targeted mice, we show that loss...... but proceeds independently of caspase-1/caspase-11 or caspase-8 function. Loss of XIAP results in aberrantly elevated ubiquitylation of RIP1 outside of TNFR complex I. Virally infected Xiap(-/-) mice present with symptoms reminiscent of XLP-2. Our data show that XIAP controls RIP3-dependent cell death and IL-1...... of XIAP or deletion of its RING domain lead to excessive cell death and IL-1β secretion from dendritic cells triggered by diverse Toll-like receptor stimuli. Aberrant IL-1β secretion is TNF dependent and requires RIP3 but is independent of cIAP1/cIAP2. The observed cell death also requires TNF and RIP3...

  8. Temporal restriction of pancreatic branching competence during embryogenesis is mirrored in differentiating embryonic stem cells.

    Science.gov (United States)

    Lim, Sue Mei; Li, Xueling; Schiesser, Jacqueline; Holland, Andrew M; Elefanty, Andrew G; Stanley, Edouard G; Micallef, Suzanne J

    2012-07-01

    To develop methods for the generation of insulin-producing β-cells for the treatment of diabetes, we have used GFP-tagged embryonic stem cells (ESCs) to elucidate the process of pancreas development. Using the reporter Pdx1(GFP/w) ESC line, we have previously described a serum-free differentiation protocol in which Pdx1-GFP(+) cells formed GFP bright (GFP(br)) epithelial buds that resembled those present in the developing mouse pancreas. In this study we extend these findings to demonstrate that these cells can undergo a process of branching morphogenesis, similar to that seen during pancreatic development of the mid-gestation embryo. These partially disaggregated embryoid bodies containing GFP(br) buds initially form epithelial ring-like structures when cultured in Matrigel. After several days in culture, these rings undergo a process of proliferation and form a ramified network of epithelial branches. Comparative analysis of explanted dissociated pancreatic buds from E13.5 Pdx1(GFP/w) embryos and ESC-derived GFP(br) buds reveal a similar process of proliferation and branching, with both embryonic Pdx1(GFP/w) branching pancreatic epithelium and ESC-derived GFP(br) branching organoids expressing markers representing epithelial (EpCAM and E-Cadherin), ductal (Mucin1), exocrine (Amylase and Carboxypeptidase 1A), and endocrine cell types (Glucagon and Somatostatin). ESC-derived branching structures also expressed a suite of genes indicative of ongoing pancreatic differentiation, paralleling gene expression within similar structures derived from the E13.5 fetal pancreas. In summary, differentiating mouse ESCs can generate pancreatic material that has significant similarity to the fetal pancreatic anlagen, providing an in vitro platform for investigating the cellular and molecular mechanisms underpinning pancreatic development.

  9. Gap Junction Communication and the Propagation of Bystander Effects Induced by Microbeam Irradiation in Human Fibroblast Cultures: The Impact of Radiation Quality

    Science.gov (United States)

    Autsavapromporn, Narongchai; Suzuki, Masao; Funayama, Tomoo; Usami, Noriko; Plante, Ianik; Yokota, Yuichiro; Mutou, Yasuko; Ikeda, Hiroko; Kobayashi, Katsumi; Kobayashi, Yasuhiko; Uchihori, Yukio; Hei, Tom K.; Azzam, Edouard I.; Murakami, Takeshi

    2014-01-01

    Understanding the mechanisms underlying the bystander effects of low doses/low fluences of low- or high-linear energy transfer (LET) radiation is relevant to radiotherapy and radiation protection. Here, we investigated the role of gap-junction intercellular communication (GJIC) in the propagation of stressful effects in confluent normal human fibroblast cultures wherein only 0.036–0.144% of cells in the population were traversed by primary radiation tracks. Confluent cells were exposed to graded doses from monochromatic 5.35 keV X ray (LET ~6 keV/μm), 18.3 MeV/u carbon ion (LET ~103 keV/μm), 13 MeV/u neon ion (LET ~380 keV/μm) or 11.5 MeV/u argon ion (LET ~1,260 keV/μm) microbeams in the presence or absence of 18-α-glycyrrhetinic acid (AGA), an inhibitor of GJIC. After 4 h incubation at 37°C, the cells were subcultured and assayed for micronucleus (MN) formation. Micronuclei were induced in a greater fraction of cells than expected based on the fraction of cells targeted by primary radiation, and the effect occurred in a dose-dependent manner with any of the radiation sources. Interestingly, MN formation for the heavy-ion microbeam irradiation in the absence of AGA was higher than in its presence at high mean absorbed doses. In contrast, there were no significant differences in cell cultures exposed to X-ray microbeam irradiation in presence or absence of AGA. This showed that the inhibition of GJIC depressed the enhancement of MN formation in bystander cells from cultures exposed to high-LET radiation but not low-LET radiation. Bystander cells recipient of growth medium harvested from 5.35 keV X-irradiated cultures experienced stress manifested in the form of excess micronucleus formation. Together, the results support the involvement of both junctional communication and secreted factor(s) in the propagation of radiation-induced stress to bystander cells. They highlight the important role of radiation quality and dose in the observed effects. PMID:23987132

  10. Restricted Airspace

    Data.gov (United States)

    Federal Laboratory Consortium — Redstone Technical Test Center has restricted airspace up to 30,000 feet ASL. Airspace encompasses R-2104 (Redstone). Airspace is used extensively for airborne/UAV...

  11. Condensin II subunit dCAP-D3 restricts retrotransposon mobilization in Drosophila somatic cells.

    Directory of Open Access Journals (Sweden)

    Andrew T Schuster

    2013-10-01

    Full Text Available Retrotransposon sequences are positioned throughout the genome of almost every eukaryote that has been sequenced. As mobilization of these elements can have detrimental effects on the transcriptional regulation and stability of an organism's genome, most organisms have evolved mechanisms to repress their movement. Here, we identify a novel role for the Drosophila melanogaster Condensin II subunit, dCAP-D3 in preventing the mobilization of retrotransposons located in somatic cell euchromatin. dCAP-D3 regulates transcription of euchromatic gene clusters which contain or are proximal to retrotransposon sequence. ChIP experiments demonstrate that dCAP-D3 binds to these loci and is important for maintaining a repressed chromatin structure within the boundaries of the retrotransposon and for repressing retrotransposon transcription. We show that dCAP-D3 prevents accumulation of double stranded DNA breaks within retrotransposon sequence, and decreased dCAP-D3 levels leads to a precise loss of retrotransposon sequence at some dCAP-D3 regulated gene clusters and a gain of sequence elsewhere in the genome. Homologous chromosomes exhibit high levels of pairing in Drosophila somatic cells, and our FISH analyses demonstrate that retrotransposon-containing euchromatic loci are regions which are actually less paired than euchromatic regions devoid of retrotransposon sequences. Decreased dCAP-D3 expression increases pairing of homologous retrotransposon-containing loci in tissue culture cells. We propose that the combined effects of dCAP-D3 deficiency on double strand break levels, chromatin structure, transcription and pairing at retrotransposon-containing loci may lead to 1 higher levels of homologous recombination between repeats flanking retrotransposons in dCAP-D3 deficient cells and 2 increased retrotransposition. These findings identify a novel role for the anti-pairing activities of dCAP-D3/Condensin II and uncover a new way in which dCAP-D3/Condensin

  12. Isolation of a T-cell clone showing HLA-DRB1*0405-restricted cytotoxicity for hematopoietic cells in a patient with aplastic anemia.

    Science.gov (United States)

    Nakao, S; Takami, A; Takamatsu, H; Zeng, W; Sugimori, N; Yamazaki, H; Miura, Y; Ueda, M; Shiobara, S; Yoshioka, T; Kaneshige, T; Yasukawa, M; Matsuda, T

    1997-05-15

    The existence of T cells capable of inhibiting in vitro hematopoiesis has been shown in aplastic anemia (AA), although whether such inhibition is mediated by a specific immune reaction involving an HLA allele remained unknown. We isolated a CD4+ Vbeta21+ T-cell clone that was most dominant among Vbeta21+ T cells in the bone marrow (BM) of an AA patient whose HLA-DRB1 alleles included 1501 and 0405. The T-cell clone named NT4.2 lysed an autologous Epstein-Barr virus-transformed lymphoblastoid cell line (LCL) and phytohemagglutinin-stimulated lymphocytes (PHA-blasts) as well as allogeneic LCLs sharing HLA-DRB1*0405. Cytotoxicity against LCL cells and PHA-blasts by NT4.2 was blocked by anti-HLA-DR monoclonal antibody (MoAb) or anti-CD3 MoAb. NT4.2 also lysed autologous BM mononuclear cells enriched with CD34+ cells that had been cultured for one week in the presence of colony-stimulating factors as well as allogeneic CD34+ cells of a normal individual carrying HLA-DRB1*0405, cultured in the same way. Moreover, NT4.2 strongly inhibited colony formation by hematopoietic progenitor cells derived from cultured CD34+ cells sharing HLA-DRB1*0405. These results indicate that the AA patient has T cells capable of killing hematopoietic cells in an HLA-DRB1*0405-restricted manner and that such cytotoxic T cells may contribute to the pathogenesis of AA.

  13. Bystander Sexual Violence Prevention Program: Outcomes for High- and Low-Risk University Men.

    Science.gov (United States)

    Elias-Lambert, Nada; Black, Beverly M

    2015-05-05

    This research reports the findings of an evaluation of a peer-facilitated, bystander sexual violence prevention program to determine its effectiveness at changing attitudes and behaviors related to sexual violence with university males who are at low- and high-risk of using sexually coercive behavior. Bystander interventions focus on men and women as bystanders to change social norms in a peer culture that supports abusive behaviors. Few studies have examined the effectiveness of these interventions with high-risk populations, which is the focus of this study. A bystander sexual violence prevention program was presented to 142 fraternity members. A quasi-experimental design utilizing pre-, post-, and follow-up surveys was used to compare the effectiveness of this prevention program with university males who are at low- and high-risk of using sexually coercive behavior in intervention and comparison groups. Participants' risk status was measured prior to the intervention using the Modified-Sexual Experiences Survey. The measures evaluated changes in attitudes (rape myth acceptance and bystander attitudes) and behaviors (sexually coercive behaviors, sexually coercive behavioral intentions, and bystander behaviors). Data analyses included Repeated-Measures Analysis of Covariances. The findings suggest that a bystander sexual violence prevention program has a positive impact on attitudes and behaviors related to sexual violence among fraternity members, however, the program had less impact on high-risk males. The results of this study will expand our ability to design programs that can have an impact on reducing sexual violence on campus by ensuring the programs are having the desired impact on the target audience.

  14. Ion beam induced luminescence: Relevance to radiation induced bystander effects

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S.B., E-mail: ahmad.rabilal@gmail.com [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); McNeill, F.E., E-mail: fmcneill@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Byun, S.H., E-mail: soohyun@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Prestwich, W.V., E-mail: prestwic@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Seymour, C., E-mail: seymouc@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Mothersill, C.E., E-mail: mothers@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada)

    2012-10-01

    The aim of this work is quantify the light emitted as a result of charged particle interaction in materials which may be of relevance to radiation induced 'bystander effects' studies. We have developed a system which employs single photon counting to measure the light emitted from samples irradiated under vacuum by a charged particle beam. The system uses a fast photomultiplier tube with a peak cathode response at 420 nm. It has been tested in a proof-of-principle experiment using polystyrene targets. Light output, as a result of irradiation, was measured. The luminescence yield appears to have a non-linear behavior with the incident ion fluence: it rises exponentially to an asymptotic value. The target was irradiated with beam energies varying from 1 to 2 MeV and showed saturation at or before an incident fluence rate of 3 Multiplication-Sign 10{sup 13} H{sup +}/cm{sup 2} s. The average saturation value for the photon output was found to be 40 Multiplication-Sign 10{sup 6} cps. Some measurements were performed using filters to study the emission at specific wavelengths. In the case of filtered light measurements, the photon output was found to saturate at 28 Multiplication-Sign 10{sup 3}, 10 Multiplication-Sign 10{sup 6}, and 35 Multiplication-Sign 10{sup 6} cps for wavelengths of 280 {+-} 5 nm, 320 {+-} 5 nm and 340 {+-} 5 nm respectively. The light output reaches a maximum value because of damage induced in the polymer. Our measurements indicate a 'damage cross section' of the order of 10{sup -14} cm{sup 2}. The average radiant intensity was found to increase at wavelengths of 280 and 320 nm when the proton energy was increased. This was not found to occur at 340 nm. In conclusion, the light emission at specific wavelengths was found to depend upon the incident proton fluence and the proton energy. The wavelengths of the emitted light measured in this study have significance for the understanding of radiation induced bystander effects.

  15. Sculpting MHC class II-restricted self and non-self peptidome by the class I Ag-processing machinery and its impact on Th-cell responses.

    Science.gov (United States)

    Spencer, Charles T; Dragovic, Srdjan M; Conant, Stephanie B; Gray, Jennifer J; Zheng, Mu; Samir, Parimal; Niu, Xinnan; Moutaftsi, Magdalini; Van Kaer, Luc; Sette, Alessandro; Link, Andrew J; Joyce, Sebastian

    2013-05-01

    It is generally assumed that the MHC class I antigen (Ag)-processing (CAP) machinery - which supplies peptides for presentation by class I molecules - plays no role in class II-restricted presentation of cytoplasmic Ags. In striking contrast to this assumption, we previously reported that proteasome inhibition, TAP deficiency or ERAAP deficiency led to dramatically altered T helper (Th)-cell responses to allograft (HY) and microbial (Listeria monocytogenes) Ags. Herein, we tested whether altered Ag processing and presentation, altered CD4(+) T-cell repertoire, or both underlay the above finding. We found that TAP deficiency and ERAAP deficiency dramatically altered the quality of class II-associated self peptides suggesting that the CAP machinery impacts class II-restricted Ag processing and presentation. Consistent with altered self peptidomes, the CD4(+) T-cell receptor repertoire of mice deficient in the CAP machinery substantially differed from that of WT animals resulting in altered CD4(+) T-cell Ag recognition patterns. These data suggest that TAP and ERAAP sculpt the class II-restricted peptidome, impacting the CD4(+) T-cell repertoire, and ultimately altering Th-cell responses. Together with our previous findings, these data suggest multiple CAP machinery components sequester or degrade MHC class II-restricted epitopes that would otherwise be capable of eliciting functional Th-cell responses.

  16. Restricted mobility of specific functional groups reduces anti-cancer drug activity in healthy cells

    DEFF Research Database (Denmark)

    Longo Martins, Murillo; Ignazzi, Rosanna; Eckert, Juergen

    2016-01-01

    The most common cancer treatments currently available are radio- and chemo-therapy. These therapies have, however, drawbacks, such as, the reduction in quality of life and the low efficiency of radiotherapy in cases of multiple metastases. To lessen these effects, we have encapsulated an anti-cancer...... drug into a biocompatible matrix. In-vitro assays indicate that this bio-nanocomposite is able to interact and cause morphological changes in cancer cells. Meanwhile, no alterations were observed in monocytes and fibroblasts, indicating that this system might carry the drug in living organisms...

  17. MR1-restricted MAIT cells display ligand discrimination and pathogen selectivity through distinct T cell receptor usage

    DEFF Research Database (Denmark)

    Gold, Marielle C.; McLaren, James E.; Reistetter, Joseph A.

    2015-01-01

    Mucosal-associated invariant T (MAIT) cells express a semi-invariant T cell receptor (TCR) that detects microbial metabolites presented by the nonpolymorphic major histocompatibility complex (MHC)-like molecule MR1. The highly conserved nature of MR1 in conjunction with biased MAIT TCRα chain usage...... is widely thought to indicate limited ligand presentation and discrimination within a pattern-like recognition system. Here, we evaluated the TCR repertoire of MAIT cells responsive to three classes of microbes. Substantial diversity and heterogeneity were apparent across the functional MAIT cell repertoire...... with this interpretation, MAIT cell clones with distinct TCRs responded differentially to a riboflavin metabolite. These results suggest that MAIT cells can discriminate between pathogen-derived ligands in a clonotype-dependent manner, providing a basis for adaptive memory via recruitment of specific repertoires shaped...

  18. MR1-restricted MAIT cells display ligand discrimination and pathogen selectivity through distinct T cell receptor usage

    DEFF Research Database (Denmark)

    Gold, Marielle C.; McLaren, James E.; Reistetter, Joseph A.

    2014-01-01

    Mucosal-associated invariant T (MAIT) cells express a semi-invariant T cell receptor (TCR) that detects microbial metabolites presented by the nonpolymorphic major histocompatibility complex (MHC)-like molecule MR1. The highly conserved nature of MR1 in conjunction with biased MAIT TCRα chain usage...... is widely thought to indicate limited ligand presentation and discrimination within a pattern-like recognition system. Here, we evaluated the TCR repertoire of MAIT cells responsive to three classes of microbes. Substantial diversity and heterogeneity were apparent across the functional MAIT cell repertoire...... with this interpretation, MAIT cell clones with distinct TCRs responded differentially to a riboflavin metabolite. These results suggest that MAIT cells can discriminate between pathogen-derived ligands in a clonotype-dependent manner, providing a basis for adaptive memory via recruitment of specific repertoires shaped...

  19. Peptide Immunization Elicits Polyomavirus-Specific MHC Class Ib-Restricted CD8 T Cells in MHC Class Ia Allogeneic Mice

    Science.gov (United States)

    Hofstetter, Amelia R.; Evavold, Brian D.

    2013-01-01

    Abstract Unlike the polymorphic MHC class Ia molecules, MHC class Ib molecules are oligomorphic or nonpolymorphic. We recently discovered a protective CD8 T cell response to mouse polyomavirus (MPyV) in H-2b haplotype mice that is restricted by H2-Q9, a member of the Qa-2 MHC class Ib family. Here, we demonstrate that immunization with a peptide corresponding to a virus capsid-derived peptide presented by Q9 also elicits MHC class Ib-restricted MPyV-specific CD8 T cells in mice of H-2s and H-2g7 strains. These findings support the concept that immunization with a single MHC class Ib-restricted peptide can expand CD8 T cells in MHC class Ia allogeneic hosts. PMID:23374150

  20. Oxygen restriction increases the infective potential of Listeria monocytogenes in vitro in Caco-2 cells and in vivo in guinea pigs

    DEFF Research Database (Denmark)

    Andersen, Jens Bo; Roldgaard, Bent; Christensen, Bjarke Bak

    2007-01-01

    : Infection of Caco-2 cells revealed that Listeria cultivated under oxygen-restricted conditions were approximately 100 fold more invasive than similar cultures grown without oxygen restriction. This was observed for exponentially growing bacteria, as well as for stationary-phase cultures. Oral dosage......Background: Listeria monocytogenes has been implicated in several food borne outbreaks as well as sporadic cases of disease. Increased understanding of the biology of this organism is important in the prevention of food borne listeriosis. The infectivity of Listeria monocytogenes ScottA, cultivated...... with and without oxygen restriction, was compared in vitro and in vivo. Fluorescent protein labels were applied to allow certain identification of Listeria cells from untagged bacteria in in vivo samples, and to distinguish between cells grown under different conditions in mixed infection experiments. Results...

  1. Controlled meal frequency without caloric restriction alters peripheral blood mononuclear cell cytokine production

    Directory of Open Access Journals (Sweden)

    Longo Dan L

    2011-03-01

    Full Text Available Abstract Background Intermittent fasting (IF improves healthy lifespan in animals by a mechanism involving reduced oxidative damage and increased resistance to stress. However, no studies have evaluated the impact of controlled meal frequency on immune responses in human subjects. Objective A study was conducted to establish the effects of controlled diets with different meal frequencies, but similar daily energy intakes, on cytokine production in healthy male and female subjects. Design In a crossover study design with an intervening washout period, healthy normal weight middle-age male and female subjects (n = 15 were maintained for 2 months on controlled on-site one meal per day (OMD or three meals per day (TMD isocaloric diets. Serum samples and peripheral blood mononuclear cells (PBMCs culture supernatants from subjects were analyzed for the presence of inflammatory markers using a multiplex assay. Results There were no significant differences in the inflammatory markers in the serum of subjects on the OMD or TMD diets. There was an increase in the capacity of PBMCs to produce cytokines in subjects during the first month on the OMD or TMD diets. Lower levels of TNF-α, IL-17, MCP-1 and MIP-1β were produced by PBMCs from subjects on the OMD versus TMD diet. Conclusions PBMCs of subjects on controlled diets exhibit hypersensitivities to cellular stimulation suggesting that stress associated with altered eating behavior might affect cytokine production by immune cells upon stimulation. Moreover, stimulated PBMCs derived from healthy individuals on a reduced meal frequency diet respond with a reduced capability to produce cytokines.

  2. Exosomes in human semen restrict HIV-1 transmission by vaginal cells and block intravaginal replication of LP-BM5 murine AIDS virus complex.

    Science.gov (United States)

    Madison, Marisa N; Jones, Philip H; Okeoma, Chioma M

    2015-08-01

    Exosomes are membranous extracellular nanovesicles secreted by diverse cell types. Exosomes from healthy human semen have been shown to inhibit HIV-1 replication and to impair progeny virus infectivity. In this study, we examined the ability of healthy human semen exosomes to restrict HIV-1 and LP-BM5 murine AIDS virus transmission in three different model systems. We show that vaginal cells internalize exosomes with concomitant transfer of functional mRNA. Semen exosomes blocked the spread of HIV-1 from vaginal epithelial cells to target cells in our cell-to-cell infection model and suppressed transmission of HIV-1 across the vaginal epithelial barrier in our trans-well model. Our in vivo model shows that human semen exosomes restrict intravaginal transmission and propagation of murine AIDS virus. Our study highlights an antiretroviral role for semen exosomes that may be harnessed for the development of novel therapeutic strategies to combat HIV-1 transmission.

  3. A novel HIV-1 restriction factor that is biologically distinct from APOBEC3 cytidine deaminases in a human T cell line CEM.NKR

    Directory of Open Access Journals (Sweden)

    Zhou Tao

    2009-04-01

    Full Text Available Abstract Background Isolation of novel retroviral restriction factors will open new avenues for anti-HIV/AIDS treatment. Although HIV-1 replication is restricted by APOBEC3G/APOBEC3F, TRIM5α, and CD317, none defend HIV-1 infection under natural conditions. Previously, we demonstrated a host factor from the human T cell line CEM.NKR that potently restricted wild-type HIV-1 replication. Interestingly, this restriction resembled the APOBEC3G/APOBEC3F pattern in that viral replication was inhibited from the second round of replication cycle at a post-entry step. Results Here, we further characterized this factor and found it distinguishable from the known anti-HIV APOBEC3 proteins. Although CEM.NKR cells expressed both APOBEC3G and APOBEC3F, their levels were at least 10 or 4-fold lower than those in H9 cells, and importantly, Vif effectively neutralized their activity. Among eight subclones isolated from CEM.NKR cells, one was relatively permissive, four were semi-permissive, and three were completely non-permissive for HIV-1 replication. When the levels of APOBEC3 expression were determined, all these clones retained similar low levels of APOBEC3DE, APOBEC3F, APOBEC3G and APOBEC3H expression, and no APOBEC3B expression was detected. Since the vif from SIVmac can effectively neutralize APOBEC3B and APOBEC3H, recombinant HIV-1 expressing this SIV gene were created. However, these viruses still failed to replicate in CEM.NKR cells. We also confirmed that HIV-1 restriction in CEM.NKR was not due to a loss of calnexin expression. Conclusion Taken together, these results not only demonstrate that all these aforementioned anti-HIV APOBEC3 proteins do not contribute to this HIV-1 restriction, but also shed light on a novel and potent HIV-1 inhibitor in CEM.NKR cells.

  4. Macrophage-tumour cell interactions: identification of MUC1 on breast cancer cells as a potential counter-receptor for the macrophage-restricted receptor, sialoadhesin.

    Science.gov (United States)

    Nath, D; Hartnell, A; Happerfield, L; Miles, D W; Burchell, J; Taylor-Papadimitriou, J; Crocker, P R

    1999-10-01

    In many carcinomas, infiltrating macrophages are commonly found closely associated with tumour cells but little is known concerning the nature or significance of adhesion molecules involved in these cellular interactions. Here we demonstrate in primary human breast cancers that sialoadhesin (Sn), a macrophage-restricted adhesion molecule, is frequently expressed on infiltrating cells that often make close contact with breast carcinoma cells. To determine whether Sn could act as a specific receptor for ligands on breast cancer cell lines, binding assays were performed with a recombinant form of the protein fused to the Fc portion of human immunoglobulin G1 (IgG1) (Sn-Fc). Sn-Fc was found to bind specifically and in a sialic acid-dependent manner to the breast cancer cell lines MCF-7, T47.D and BT-20 both in solid- and solution-phase binding assays. To investigate the nature of the sialoglycoproteins recognized by Sn on breast cancer cells, MCF-7 cells were labelled with [6-3H]glucosamine. Following precipitation with Sn-Fc, a major band of approximately 240000 MW was revealed, which was shown in reprecipitation and Western blotting experiments to be the epithelial mucin, MUC1.

  5. Peripheral blood-derived bovine dendritic cells promote IgG1-restricted B cell responses in vitro.

    Science.gov (United States)

    Bajer, Anna A; Garcia-Tapia, David; Jordan, Kimberly R; Haas, Karen M; Werling, Dirk; Howard, Chris J; Estes, D Mark

    2003-01-01

    Regulation of humoral responses involves multiple cell types including the requirements for cognate interactions between T and B cells to drive CD40-dependent responses to T-dependent antigens. A third cell type has also been shown to play an essential role, the dendritic cell (DC). We demonstrate that bovine peripheral blood-derived (PB)-DC are similar in function to features described for human interstitial DC including the production of signature type 2 cytokines [interleukin (IL)-13, IL-10]. PB-DC express moderate-to-high costimulatory molecule expression, and major histocompatibility complex class II is negative for CD14 expression and has low or no expression of CD11c. Consistent with the interstitial phenotype is the ability of PB-DC to influence B cell activation and differentiation via direct expression of CD40L and type 2 cytokines. Collectively, these results suggest that direct B cell-DC interactions may promote an immunoglobulin-isotype expression pattern consistent with type 2 responses, independent of direct T cell involvement.

  6. Restrictive Palivizumab Use Does Not Lead to Increased Morbidity and Mortality in Pediatric Hematopoietic Stem Cell Transplantation Patients.

    Science.gov (United States)

    Teusink-Cross, Ashley; Davies, Stella M; Danziger-Isakov, Lara; El-Bietar, Javier; Grimley, Michael S

    2016-10-01

    Respiratory syncytial virus (RSV) is a common cause of infection in immunocompromised patients and can lead to significant morbidity and mortality in pediatric hematopoietic stem cell transplantation (HSCT) patients and patients with a primary immune deficiency (PID). Palivizumab is a humanized monoclonal antibody that targets the F glycoprotein on the surface of the RSV virus, preventing RSV replication. Palivizumab was initially licensed for the prevention of RSV infections in children at high risk of severe disease. Since licensure, the American Academy of Pediatrics (AAP) has issued guidelines to help ensure appropriate use of palivizumab in pediatric patients. In the 2014 edition of the guidelines, the AAP recognizes that severe and fatal disease secondary to RSV can be seen in patients receiving chemotherapy or patients who are immunocompromised because of other conditions. However, they recognize that no large clinical trials exist to support the use of palivizumab, and efficacy and safety data in this population are limited. Despite this, the AAP recommends considering prophylaxis for children younger than 24 months who are profoundly immunocompromised during the RSV season. Because of the high cost of palivizumab, the uncertainty of its efficacy as prophylaxis in hospitalized pediatric HSCT and PID patients, and secondary to recent data from our center that suggested immunocompromised patients diagnosed with RSV did not have worse outcomes, we implemented very restrictive criteria for the use of palivizumab in the 2015 to 2016 RSV season in our pediatric HSCT population. Despite these strict criteria, there was no change in the number of patients developing RSV during this season compared with previous seasons, and there was no change in RSV course in those patients developing RSV compared with previous seasons. Restricted use also resulted in a significant dose and cost savings. Based on our experience, we recommend only administering prophylaxis

  7. Propranolol Restricts the Mobility of Single EGF-Receptors on the Cell Surface before Their Internalization

    Science.gov (United States)

    Otero, Carolina; Linke, Max; Sanchez, Paula; González, Alfonso; Schaap, Iwan A. T.

    2013-01-01

    The epidermal growth factor receptor is involved in morphogenesis, proliferation and cell migration. Its up-regulation during tumorigenesis makes this receptor an interesting therapeutic target. In the absence of the ligand, the inhibition of phosphatidic acid phosphohydrolase activity by propranolol treatment leads to internalization of empty/inactive receptors. The molecular events involved in this endocytosis remain unknown. Here, we quantified the effects of propranolol on the mobility of single quantum-dot labelled receptors before the actual internalization took place. The single receptors showed a clear stop-and-go motion; their diffusive tracks were continuously interrupted by sub-second stalling events, presumably caused by transient clustering. In the presence of propranolol we found that: i) the diffusion rate reduced by 22 %, which indicates an increase in drag of the receptor. Atomic force microscopy measurements did not show an increase of the effective membrane tension, such that clustering of the receptor remains the likely mechanism for its reduced mobility. ii) The receptor got frequently stalled for longer periods of multiple seconds, which may signal the first step of the internalization process. PMID:24349439

  8. Booze, Bars, and Bystander Behavior: People Who Consumed Alcohol Help Faster in the Presence of Others.

    Science.gov (United States)

    van Bommel, Marco; van Prooijen, Jan-Willem; Elffers, Henk; Van Lange, Paul A M

    2016-01-01

    People help each other less often and less quickly when bystanders are present. In this paper, we propose that alcohol consumption could attenuate or reverse this so-called bystander effect. Alcohol impairs people cognitively and perceptually, leading them to think less about the presence of others and behave less inhibited. Moreover, alcohol makes people more prone to see the benefits of helping and not the costs. To provide an initial test of these lines of reasoning, we invited visitors of bars in Amsterdam to join our study at a secluded spot at the bar. We manipulated bystander presence, and at the end of the study, we measured alcohol consumption. When participants took their seats, the experimenter dropped some items. We measured how many items were picked up and how quickly participants engaged in helping. Results revealed that alcohol did not influence the bystander effect in terms of the amount of help given. But importantly, it did influence the bystander effect in terms of response times: people who consumed alcohol actually came to aid faster in the presence of others.

  9. Booze, Bars, and Bystander Behavior: People who Consumed Alcohol Help Faster in the Presence of Others.

    Directory of Open Access Journals (Sweden)

    Marco eVan Bommel

    2016-02-01

    Full Text Available People help each other less often and less quickly when bystanders are present. In this paper, we propose that alcohol consumption could attenuate or reverse this so-called bystander effect. Alcohol impairs people cognitively and perceptually, leading them to think less about the presence of others and behave less inhibited. Moreover, alcohol makes people more prone to see the benefits of helping and not the costs. To provide an initial test of these lines of reasoning, we invited visitors of bars in Amsterdam to join our study at a secluded spot at the bar. We manipulated bystander presence, and at the end of the study, we measured alcohol consumption. When participants took their seats, the experimenter dropped some items. We measured how many items were picked up and how quickly participants engaged in helping. Results revealed that alcohol did not influence the bystander effect in terms of the amount of help given. But importantly, it did influence the bystander effect in terms of response times: People who consumed alcohol actually came to aid faster in the presence of others.

  10. Oxygen restriction increases the infective potential of Listeria monocytogenes in vitro in Caco-2 cells and in vivo in guinea pigs

    Directory of Open Access Journals (Sweden)

    Licht Tine

    2007-06-01

    Full Text Available Abstract Background Listeria monocytogenes has been implicated in several food borne outbreaks as well as sporadic cases of disease. Increased understanding of the biology of this organism is important in the prevention of food borne listeriosis. The infectivity of Listeria monocytogenes ScottA, cultivated with and without oxygen restriction, was compared in vitro and in vivo. Fluorescent protein labels were applied to allow certain identification of Listeria cells from untagged bacteria in in vivo samples, and to distinguish between cells grown under different conditions in mixed infection experiments. Results Infection of Caco-2 cells revealed that Listeria cultivated under oxygen-restricted conditions were approximately 100 fold more invasive than similar cultures grown without oxygen restriction. This was observed for exponentially growing bacteria, as well as for stationary-phase cultures. Oral dosage of guinea pigs with Listeria resulted in a significantly higher prevalence (p Listeria in fecal samples was observed after dosage with oxygen-restricted bacteria. These differences were seen after challenge with single Listeria cultures, as well as with a mixture of two cultures grown with and without oxygen restriction. Conclusion Our results show for the first time that the environmental conditions to which L. monocytogenes is exposed prior to ingestion are decisive for its in vivo infective potential in the gastrointestinal tract after passage of the gastric barrier. This is highly relevant for safety assessment of this organism in food.

  11. A Longitudinal Study of the Associations between Moral Disengagement and Active Defending versus Passive Bystanding during Bullying Situations

    Science.gov (United States)

    Doramajian, Caroline; Bukowski, William M.

    2015-01-01

    This study investigated the prospective association between moral disengagement and bystander behaviors in bullying situations, including both defending and passive bystanding. A diverse sample of Canadian school children (N = 130; 68 boys and 62 girls; mean age = 11.36 years) participated in a three-wave longitudinal study over a 4-month period.…

  12. H2-M3-restricted CD8+ T cells induced by peptide-pulsed dendritic cells confer protection against Mycobacterium tuberculosis.

    Science.gov (United States)

    Doi, Takehiko; Yamada, Hisakata; Yajima, Toshiki; Wajjwalku, Worawidh; Hara, Toshiro; Yoshikai, Yasunobu

    2007-03-15

    One of the oligopolymorphic MHC class Ib molecules, H2-M3, presents N-formylated peptides derived from bacteria. In this study, we tested the ability of an H2-M3-binding peptide, TB2, to induce protection in C57BL/6 mice against Mycobacterium tuberculosis. Immunization with bone marrow-derived dendritic cell (BMDC) pulsed with TB2 or a MHC class Ia-binding peptide, MPT64(190-198) elicited an expansion of Ag-specific CD8+ T cells in the spleen and the lung. The number of TB2-specific CD8+ T cells reached a peak on day 6, contracted with kinetics similar to MPT64(190-198)-specific CD8+ T cells and was maintained at an appreciable level for at least 60 days. The TB2-specific CD8+ T cells produced less effector cytokines but have stronger cytotoxic activity than MPT64(190-198)-specific CD8+ T cells. Mice immunized with TB2-pulsed BMDC as well as those with MPT64(190-198)-pulsed BMDC showed significant protection against an intratracheal challenge with M. tuberculosis H37Rv. However, histopathology of the lung in mice immunized with TB2-pulsed BMDC was different from mice immunized with MPT64(190-198)-pulsed BMDC. Our results suggest that immunization with BMDC pulsed with MHC class Ib-restricted peptides would be a useful vaccination strategy against M. tuberculosis.

  13. Tetherin does not significantly restrict dendritic cell-mediated HIV-1 transmission and its expression is upregulated by newly synthesized HIV-1 Nef

    Directory of Open Access Journals (Sweden)

    Wu Li

    2011-04-01

    Full Text Available Abstract Background Dendritic cells (DCs are among the first cells to encounter HIV-1 and play important roles in viral transmission and pathogenesis. Immature DCs allow productive HIV-1 replication and long-term viral dissemination. The pro-inflammatory factor lipopolysaccharide (LPS induces DC maturation and enhances the efficiency of DC-mediated HIV-1 transmission. Type I interferon (IFN partially inhibits HIV-1 replication and cell-cell transmission in CD4+ T cells and macrophages. Tetherin is a type I IFN-inducible restriction factor that blocks HIV-1 release and modulates CD4+ T cell-mediated cell-to-cell transmission of HIV-1. However, the role of type I IFN and tetherin in HIV-1 infection of DCs and DC-mediated viral transmission remains unknown. Results We demonstrated that IFN-alpha (IFNα-induced mature DCs restricted HIV-1 replication and trans-infection of CD4+ T cells. Tetherin expression in monocyte-derived immature DCs was undetectable or very low. High levels of tetherin were transiently expressed in LPS- and IFNα-induced mature DCs, while HIV-1 localized into distinct patches in these DCs. Knockdown of induced tetherin in LPS- or IFNα-matured DCs modestly enhanced HIV-1 transmission to CD4+ T cells, but had no significant effect on wild-type HIV-1 replication in mature DCs. Intriguingly, we found that HIV-1 replication in immature DCs induced significant tetherin expression in a Nef-dependent manner. Conclusions The restriction of HIV-1 replication and transmission in IFNα-induced mature DCs indicates a potent anti-HIV-1 response; however, high levels of tetherin induced in mature DCs cannot significantly restrict wild-type HIV-1 release and DC-mediated HIV-1 transmission. Nef-dependent tetherin induction in HIV-1-infected immature DCs suggests an innate immune response of DCs to HIV-1 infection.

  14. Caloric Restriction reduces inflammation and improves T cell-mediated immune response in obese mice but concomitant consumption of curcumin/piperine adds no further benefit

    Science.gov (United States)

    Obesity is associated with low-grade inflammation and impaired immune response. Caloric restriction (CR) has been shown to inhibit inflammatory response and enhance cell-mediated immune function. Curcumin, the bioactive phenolic component of turmeric spice, is proposed to have anti-obesity and anti-...

  15. Identification of a cross-reactive HLA-DRB1*0301-restricted CD4 T cell response directed against cholesterol-binding cytolysins from two different pathogens.

    Science.gov (United States)

    Paschen, Annette; Song, Mingxia; Schenk, Simone; Janda, Jozef; Nguyen, Xuan Duc; Osen, Wolfram; Schadendorf, Dirk; Geginat, Gernot

    2006-07-01

    Cholesterol-binding cytolysins constitute an evolutionarily conserved family of pore-forming proteins expressed by different gram-positive pathogens. Listeriolysin O, one well-characterized member of the cytolysin family, is also known to induce specific CD4 and CD8 T cell responses upon infection of mice with Listeria monocytogenes. Here we describe an HLA-DRB1*0301-restricted listeriolysin O-derived T cell epitope that is conserved among several members of the cytolysin family. An HLA-DRB1*0301-restricted CD4+ T cell line, established from spleen lymphocytes of L. monocytogenes-infected HLA-DRB1*0301-transgenic mice, cross-reacted with a homologous peptide from perfringolysin O, a cytolysin expressed by Clostridium perfringens. Ex vivo analysis of infected mice revealed an even broader cross-reaction of T cells with homologous peptides derived from perfringolysin O, streptolysin O, and cereolysin O. Interestingly, a cross-reactive memory CD4+ T cell response against the homologous peptides derived from listeriolysin O and perfringolysin O could also be detected in the blood from healthy HLA-DRB1*0301+ human donors. Remarkably, this response was even present in donors who did not exhibit a memory T cell reactivity against a second, non-conserved HLA-DRB1*0301-restricted LLO-derived CD4 T cell epitope, suggesting that cytolysin-producing bacteria other than L. monocytogenes can stimulate a cross-reactive cytolysin-specific immunity.

  16. Completion of hepatitis C virus replication cycle in heterokaryons excludes dominant restrictions in human non-liver and mouse liver cell lines.

    Directory of Open Access Journals (Sweden)

    Anne Frentzen

    2011-04-01

    Full Text Available Hepatitis C virus (HCV is hepatotropic and only infects humans and chimpanzees. Consequently, an immunocompetent small animal model is lacking. The restricted tropism of HCV likely reflects specific host factor requirements. We investigated if dominant restriction factors expressed in non-liver or non-human cell lines inhibit HCV propagation thus rendering these cells non-permissive. To this end we explored if HCV completes its replication cycle in heterokaryons between human liver cell lines and non-permissive cell lines from human non-liver or mouse liver origin. Despite functional viral pattern recognition pathways and responsiveness to interferon, virus production was observed in all fused cells and was only ablated when cells were treated with exogenous interferon. These results exclude that constitutive or virus-induced expression of dominant restriction factors prevents propagation of HCV in these cell types, which has important implications for HCV tissue and species tropism. In turn, these data strongly advocate transgenic approaches of crucial human HCV cofactors to establish an immunocompetent small animal model.

  17. Cell type-restricted activity of hnRNPM promotes breast cancer metastasis via regulating alternative splicing.

    Science.gov (United States)

    Xu, Yilin; Gao, Xin D; Lee, Jae-Hyung; Huang, Huilin; Tan, Haiyan; Ahn, Jaegyoon; Reinke, Lauren M; Peter, Marcus E; Feng, Yue; Gius, David; Siziopikou, Kalliopi P; Peng, Junmin; Xiao, Xinshu; Cheng, Chonghui

    2014-06-01

    Tumor metastasis remains the major cause of cancer-related death, but its molecular basis is still not well understood. Here we uncovered a splicing-mediated pathway that is essential for breast cancer metastasis. We show that the RNA-binding protein heterogeneous nuclear ribonucleoprotein M (hnRNPM) promotes breast cancer metastasis by activating the switch of alternative splicing that occurs during epithelial-mesenchymal transition (EMT). Genome-wide deep sequencing analysis suggests that hnRNPM potentiates TGFβ signaling and identifies CD44 as a key downstream target of hnRNPM. hnRNPM ablation prevents TGFβ-induced EMT and inhibits breast cancer metastasis in mice, whereas enforced expression of the specific CD44 standard (CD44s) splice isoform overrides the loss of hnRNPM and permits EMT and metastasis. Mechanistically, we demonstrate that the ubiquitously expressed hnRNPM acts in a mesenchymal-specific manner to precisely control CD44 splice isoform switching during EMT. This restricted cell-type activity of hnRNPM is achieved by competition with ESRP1, an epithelial splicing regulator that binds to the same cis-regulatory RNA elements as hnRNPM and is repressed during EMT. Importantly, hnRNPM is associated with aggressive breast cancer and correlates with increased CD44s in patient specimens. These findings demonstrate a novel molecular mechanism through which tumor metastasis is endowed by the hnRNPM-mediated splicing program.

  18. A model of the radiation-induced bystander effect based on an analogy with ferromagnets. Application to modelling tissue response in a uniform field

    Science.gov (United States)

    Vassiliev, O. N.

    2014-12-01

    We propose a model of the radiation-induced bystander effect based on an analogy with magnetic systems. The main benefit of this approach is that it allowed us to apply powerful methods of statistical mechanics. The model exploits the similarity between how spin-spin interactions result in correlations of spin states in ferromagnets, and how signalling from a damaged cell reduces chances of survival of neighbour cells, resulting in correlated cell states. At the root of the model is a classical Hamiltonian, similar to that of an Ising ferromagnet with long-range interactions. The formalism is developed in the framework of the Mean Field Theory. It is applied to modelling tissue response in a uniform radiation field. In this case the results are remarkably simple and at the same time nontrivial. They include cell survival curves, expressions for the tumour control probability and effects of fractionation. The model extends beyond of what is normally considered as bystander effects. It offers an insight into low-dose hypersensitivity and into mechanisms behind threshold doses for deterministic effects.

  19. A novel HLA-B18 restricted CD8+ T cell epitope is efficiently cross-presented by dendritic cells from soluble tumor antigen.

    Directory of Open Access Journals (Sweden)

    Rona Y Zhao

    Full Text Available NY-ESO-1 has been a major target of many immunotherapy trials because it is expressed by various cancers and is highly immunogenic. In this study, we have identified a novel HLA-B*1801-restricted CD8(+ T cell epitope, NY-ESO-1(88-96 (LEFYLAMPF and compared its direct- and cross-presentation to that of the reported NY-ESO-1(157-165 epitope restricted to HLA-A*0201. Although both epitopes were readily cross-presented by DCs exposed to various forms of full-length NY-ESO-1 antigen, remarkably NY-ESO-1(88-96 is much more efficiently cross-presented from the soluble form, than NY-ESO-1(157-165. On the other hand, NY-ESO-1(157-165 is efficiently presented by NY-ESO-1-expressing tumor cells and its presentation was not enhanced by IFN-γ treatment, which induced immunoproteasome as demonstrated by Western blots and functionally a decreased presentation of Melan A(26-35; whereas NY-ESO-1(88-96 was very inefficiently presented by the same tumor cell lines, except for one that expressed high level of immunoproteasome. It was only presented when the tumor cells were first IFN-γ treated, followed by infection with recombinant vaccinia virus encoding NY-ESO-1, which dramatically increased NY-ESO-1 expression. These data indicate that the presentation of NY-ESO-1(88-96 is immunoproteasome dependent. Furthermore, a survey was conducted on multiple samples collected from HLA-B18(+ melanoma patients. Surprisingly, all the detectable responses to NY-ESO-1(88-96 from patients, including those who received NY-ESO-1 ISCOMATRIX™ vaccine were induced spontaneously. Taken together, these results imply that some epitopes can be inefficiently presented by tumor cells although the corresponding CD8(+ T cell responses are efficiently primed in vivo by DCs cross-presenting these epitopes. The potential implications for cancer vaccine strategies are further discussed.

  20. Identification of conserved subdominant HIV Type 1 CD8(+) T Cell epitopes restricted within common HLA Supertypes for therapeutic HIV Type 1 vaccines

    DEFF Research Database (Denmark)

    Karlsson, Ingrid; Kløverpris, Henrik; Jensen, Kristoffer Jarlov;

    2012-01-01

    The high HIV-1 prevalence, up to 4.6% in Guinea-Bissau, West Africa, makes it a relevant location for testing of therapeutic vaccines. With the aim of performing a clinical study in Guinea-Bissau, after first testing the vaccine for safety in Denmark, Europe, we here describe the design...... of a universal epitope peptide-based T cell vaccine with relevance for any geographic locations. The two major obstacles when designing such a vaccine are the high diversities of the HIV-1 genome and of the human major histocompatibility complex (MHC) class I. We selected 15 CD8-restricted epitopes predicted......-specific, HLA-restricted T cell specificities using peptide-MHC class I tetramer labeling of CD8(+) T cells from HIV-1-infected individuals. The selected vaccine epitopes are infrequently targeted in HIV-1-infected individuals from both locations. Moreover, we HLA-typed HIV-1-infected individuals...

  1. Development of a T cell receptor targeting an HLA-A*0201 restricted epitope from the cancer-testis antigen SSX2 for adoptive immunotherapy of cancer.

    Directory of Open Access Journals (Sweden)

    Daniel Abate-Daga

    Full Text Available The clinical success of adoptive immunotherapy of cancer relies on the selection of target antigens that are highly expressed in tumor cells but absent in essential normal tissues. A group of genes that encode the cancer/testis or cancer germline antigens have been proposed as ideal targets for immunotherapy due to their high expression in multiple cancer types and their restricted expression in immunoprivileged normal tissues. In the present work we report the isolation and characterization of human T cell receptors (TCRs with specificity for synovial sarcoma X breakpoint 2 (SSX2, a cancer/testis antigen expressed in melanoma, prostate cancer, lymphoma, multiple myeloma and pancreatic cancer, among other tumors. We isolated seven HLA-A2 restricted T cell receptors from natural T cell clones derived from tumor-infiltrated lymph nodes of two SSX2-seropositive melanoma patients, and selected four TCRs for cloning into retroviral vectors. Peripheral blood lymphocytes (PBL transduced with three of four SSX2 TCRs showed SSX241-49 (KASEKIFYV peptide specific reactivity, tumor cell recognition and tetramer binding. One of these, TCR-5, exhibited tetramer binding in both CD4 and CD8 cells and was selected for further studies. Antigen-specific and HLA-A*0201-restricted interferon-γ release, cell lysis and lymphocyte proliferation was observed following culture of TCR engineered human PBL with relevant tumor cell lines. Codon optimization was found to increase TCR-5 expression in transduced T cells, and this construct has been selected for development of clinical grade viral vector producing cells. The tumor-specific pattern of expression of SSX2, along with the potent and selective activity of TCR-5, makes this TCR an attractive candidate for potential TCR gene therapy to treat multiple cancer histologies.

  2. Association of bystander cardiopulmonary resuscitation and survival according to ambulance response-times after out-of-hospital cardiac arrest

    DEFF Research Database (Denmark)

    Rajan, Shahzleen; Wissenberg, Mads; Folke, Fredrik;

    2016-01-01

    chances decreased both for patients with bystander CPR and those without. However, the contrast between the survival chances of patients with vs. without bystander CPR increased over time: within 5 minutes, 30-day survival was 14.5% (95% CI: 12.8-16.4) vs. 6.3% (95% CI: 5.1-7.6), corresponding to 2.......3 times higher chances of survival associated with bystander CPR; within 10 minutes, 30-day survival chances were 6.7% (95% CI: 5.4-8.1) vs. 2.2% (95% CI: 1.5-3.1), corresponding to 3.0 times higher chances of 30-day survival associated with bystander CPR. The contrast in 30-day survival became...... statistically insignificant when response time exceeded 13 minutes (bystander CPR vs. no bystander CPR: 3.7% [95% CI: 2.2-5.4] vs. 1.5% [95% CI: 0.6-2.7]) but 30-day survival was still 2.5 times higher associated with bystander CPR. Based on the model and Danish OHCA Statistics, an additional of 233 patients...

  3. Raising a Red Flag on Dating Violence: Evaluation of a Low-Resource, College-Based Bystander Behavior Intervention Program.

    Science.gov (United States)

    Borsky, Amanda E; McDonnell, Karen; Turner, Monique Mitchell; Rimal, Rajiv

    2016-03-09

    Encouraging bystanders to intervene safely and effectively in situations that could escalate to violence-known as bystander behavior programs-is a growing yet largely untested strategy to prevent dating violence. Using a quasi-experimental design, we evaluate a low-resource, low-intensity intervention aimed at preventing dating violence among college students. The integrated behavioral model (IBM) was used to guide the evaluation. We also assess which IBM variables were most strongly associated with bystander behaviors. Participants were drawn from two Virginia colleges that predominantly train females in the health profession sciences. The intervention group (n = 329) participated in a university-wide bystander behavior intervention consisting of a 30-min presentation on dating violence at new-student orientation and a week-long "red flag" social marketing campaign on campus to raise awareness of dating violence. Controlling for changes at the comparison university, results showed an increase in bystander behaviors, such as encouraging a friend who may be in an abusive relationship to get help, after the intervention and adjusting for potential confounders (increase of 1.41 bystander behaviors, p = .04). However, no significant changes were found for bystander intentions, self-efficacy, social norms, or attitudes related to dating violence from pre- to post-intervention. Self-efficacy had a direct relationship with bystander behaviors. Results suggest that low-resource interventions have a modest effect on increasing bystander behaviors. However, higher resource interventions likely are needed for a larger impact, especially among students who already demonstrate strong baseline intentions to intervene and prevent dating violence.

  4. Vulnerable Children in Varying Classroom Contexts Bystanders' Behaviors Moderate the Effects of Risk Factors on Victimization

    NARCIS (Netherlands)

    Kärnä, A.; Voeten, M.J.M.; Poskiparta, E.H.; Salmivalli, C.

    2010-01-01

    We examined whether the bystanders' behaviors in bullying situations influence vulnerable students' risk for victimization. The sample consisted of 6,980 primary school children from Grades 3-5, who were nested within 378 classrooms in 77 schools. These students filled out Internet-based questionnai

  5. Vulnerable Children in Varying Classroom Contexts: Bystanders' Behaviors Moderate the Effects of Risk Factors on Victimization

    Science.gov (United States)

    Karna, Antti; Voeten, Marinus; Poskiparta, Elisa; Salmivalli, Christina

    2010-01-01

    We examined whether the bystanders' behaviors in bullying situations influence vulnerable students' risk for victimization. The sample consisted of 6,980 primary school children from Grades 3-5, who were nested within 378 classrooms in 77 schools. These students filled out Internet-based questionnaires in their schools' computer labs. The results…

  6. Bystander Intervention, Bullying, and Victimization: A Multilevel Analysis of New Zealand High Schools

    Science.gov (United States)

    Denny, Simon; Peterson, Elizabeth R.; Stuart, Jaimee; Utter, Jennifer; Bullen, Pat; Fleming, Theresa; Ameratunga, Shanthi; Clark, Terryann; Milfont, Taciano

    2015-01-01

    This study examines the association between schools and student bullying behaviors and victimization among a nationally representative sample (N = 9,107) of New Zealand high school students. In particular, the study sought to explore the role of characteristics of schools and school culture with respect to bystander behavior, while controlling for…

  7. BYSTANDERS, ADAPTIVE RESPONSES AND GENOMIC INSTABILITY - POTENTIAL MODIFIERS OF LOW-DOSE CANCER RESPONSES.

    Science.gov (United States)

    Bystanders, Adaptive Responses and Genomic Instability -Potential Modifiers ofLow-DoseCancer Responses.There has been a concerted effort in the field of radiation biology to better understand cellularresponses that could have an impact on the estin1ation of cancer...

  8. Tell the Teacher or Tell the Bully Off: Children's Strategy Production for Bystanders to Bullying

    Science.gov (United States)

    Rock, Patrick F.; Baird, Jodie A.

    2012-01-01

    Although children's reticence to intervene as bystanders to bullying is well established, the reasons for their inaction remain unclear. One possibility is that they are incapable of generating appropriate response strategies in these situations. This study examined the number and type of strategies children (N = 104, 6-11 years) could generate…

  9. R.U. Ready?: Peer Education and Bystander Intervention Sexual Assault Programming

    Science.gov (United States)

    Schweer, Jen Luettel; Heather, Katie; Kay, Kathryn; Stewart, K. Leigh; Kovach, Laura

    2012-01-01

    R.U. Ready? at Georgetown University is an annual sexual assault awareness event that incorporates peer education and resources with opportunities for students, staff, and faculty to dialogue about providing bystander intervention throughout the campus community. Beyond dialogue, participants learn about student activism and the resources and…

  10. Acting in solidarity : Testing an extended dual pathway model of collective action by bystander group members

    NARCIS (Netherlands)

    Saab, Rim; Tausch, Nicole; Spears, Russell; Cheung, Wing-Yee

    2015-01-01

    We examined predictors of collective action among bystander group members in solidarity with a disadvantaged group by extending the dual pathway model of collective action, which proposes one efficacy-based and one emotion-based path to collective action (Van Zomeren, Spears, Fischer, & Leach, 2004)

  11. A Bystander Bullying Psychoeducation Program with Middle School Students: A Preliminary Report

    Science.gov (United States)

    Midgett, Aida; Doumas, Diana; Sears, Dara; Lundquist, Amanda; Hausheer, Robin

    2015-01-01

    This study evaluated the effectiveness of a brief, stand-alone bystander bullying psychoeducation program for middle school students. The purpose of the program was to train students to take action as peer advocates. Pre- and post-tests indicated that after completing the 90-minute psychoeducation program, students reported an increase in their…

  12. A Meta-Analysis of School-Based Bullying Prevention Programs' Effects on Bystander Intervention Behavior

    Science.gov (United States)

    Polanin, Joshua R.; Espelage, Dorothy L.; Pigott, Therese D.

    2012-01-01

    This meta-analysis synthesized bullying prevention programs' effectiveness at increasing bystander intervention in bullying situations. Evidence from 12 school-based programs, involving 12,874 students, indicated that overall the programs were successful (Hedges's g = 0.20, 95% confidence interval [CI] = 0.11 to 0.29, p = 0.001), with larger…

  13. The role of bystanders during rescue and resuscitation of drowning victims

    NARCIS (Netherlands)

    Venema, Allart M.; Groothoff, Johan W.; Bierens, Joost J. L. M.

    2010-01-01

    Background: Bystanders make a critical difference in the survival of drowning victims. Little information on their role before arrival of the Emergency Medical Services (EMS) is available in the scientific literature. In a descriptive study, this role is investigated. Methods and results: We studied

  14. Reducing Sexual Violence on Campus: The Role of Student Leaders as Empowered Bystanders

    Science.gov (United States)

    Banyard, Victoria L.; Moynihan, Mary M.; Crossman, Maria T.

    2009-01-01

    Sexual violence is a widespread problem for college communities. Students, faculty, and staff are increasingly involved in prevention efforts. To date, however, evaluation of sexual violence prevention programs has shown mixed results. One promising new practice teaches segments of college communities to be engaged, positive bystanders. It aims to…

  15. Using Role-Taking and Behavioral Mimicking in Games to Increase Awareness on the Bystander Effect

    DEFF Research Database (Denmark)

    Soegaard Andersen, Josephine; Schoenau-Fog, Henrik

    2015-01-01

    with behavioral mimicking. The game concept should include a relatable (preferably player modifiable) avatar, so the player can relate and adhere to the empathy and intent to help. Since the bystander effect takes place in groups where deindividuation also is common, this should require a behavioral change...

  16. Using a Multimedia Social Marketing Campaign to Increase Active Bystanders on the College Campus

    Science.gov (United States)

    Potter, Sharyn J.

    2012-01-01

    Objective: To evaluate the campus-wide administration of the Know Your Power bystander-oriented social marketing campaign. Participants: Undergraduate students at a public college were invited to participate in a public awareness survey before and after the 6-week campaign administration in February and March 2009. Methods: Pretest and posttests…

  17. Bystander Behavior in Bullying Situations: Basic Moral Sensitivity, Moral Disengagement and Defender Self-Efficacy

    Science.gov (United States)

    Thornberg, Robert; Jungert, Tomas

    2013-01-01

    The aim of the present study was to investigate how basic moral sensitivity in bullying, moral disengagement in bullying and defender self-efficacy were related to different bystander behaviors in bullying. Therefore, we examined pathways that linked students' basic moral sensitivity, moral disengagement, and defender self-efficacy to different…

  18. Bystander Motivation in Bullying Incidents: To Intervene or Not to Intervene?

    Directory of Open Access Journals (Sweden)

    Robert Thornberg

    2012-08-01

    Full Text Available Introduction: This research sought to extend knowledge about bystanders in bullying situations with a focus on the motivations that lead them to different responses. The 2 primary goals of this study were to investigate the reasons for children’s decisions to help or not to help a victim when witnessing bullying, and to generate a grounded theory (or conceptual framework of bystander motivation in bullying situations.Methods: Thirty students ranging in age from 9 to 15 years (M=11.9; SD=1.7 from an elementary and middle school in the southeastern United States participated in this study. Open- ended, semistructured interviews were used, and sessions ranged from 30 to 45 minutes. We conducted qualitative methodology and analyses to gain an in-depth understanding of children’s perspectives and concerns when witnessing bullying.Results: A key finding was a conceptual framework of bystander motivation to intervene in bullying situations suggesting that deciding whether to help or not help the victim in a bullying situation depends on how bystanders define and evaluate the situation, the social context, and their own agency. Qualitative analysis revealed 5 themes related to bystander motives and included: interpretation of harm in the bullying situation, emotional reactions, social evaluating, moral evaluating, and intervention self-efficacy.Conclusion: Given the themes that emerged surrounding bystanders’ motives to intervene or abstain from intervening, respondents reported 3 key elements that need to be confirmed in future research and that may have implications for future work on bullying prevention. These included: first, the potential importance of clear communication to children that adults expect bystanders to intervene when witnessing bullying; second, the potential of direct education about how bystanders can interveneto increase children’s self-efficacy as defenders of those who are victims of bullying; and third, the assumption

  19. Bystander effects in UV-induced genomic instability: Antioxidants inhibit delayed mutagenesis induced by ultraviolet A and B radiation

    Directory of Open Access Journals (Sweden)

    Dahle Jostein

    2005-01-01

    glutathione. Previously, we have shown that ultraviolet induced delayed mutations may be induced via a bystander effect and that this effect is 5-fold higher for UVB radiation than for UVA radiation. Therefore, we propose that the antioxidants inhibit an ultraviolet radiation-induced bystander effect and that the effect is transmitted via the medium and via an internal transfer between cells, like gap junctional intercellular communication, for UVB radiation and only by the latter mechanism for UVA radiation.

  20. Differential in vivo clearance and response to secondary heterologous infections by H2(b)-restricted dengue virus-specific CD8+ T cells.

    Science.gov (United States)

    Beaumier, Coreen M; Jaiswal, Smita; West, Kim Y; Friberg, Heather; Mathew, Anuja; Rothman, Alan L

    2010-10-01

    Cytotoxic T lymphocytes (CTL) are hypothesized to play a role in clearance during primary dengue virus (DENV) infections, and contribute to immunopathology during secondary heterologous infections in humans. We previously reported skewed T-cell responses to secondary DENV infection in BALB/c (H-2(d)) mice, reproducing characteristics of human DENV infection. To set the stage for using widely available transgenic and knockout mice, we extended these studies to identify DENV-specific T-cell responses in C57BL/6 (H-2(b)) mice. We identified dominant CD8+ T-cell responses to H-2D(b)-restricted epitopes on the DENV NS4a (aa 249-265) and NS5 (aa 521-537) proteins. High frequencies of IFN-γ- and TNF-α-producing T cells directed at both epitopes were detected following primary infection with all four DENV serotypes, and were augmented by secondary DENV infections. In vivo cytotoxicity assays demonstrated rapid clearance of target cells pulsed with the NS4a peptide; in contrast, NS5 peptide-pulsed target cells were poorly cleared in vivo. These data characterize two H-2(b)-restricted T-cell epitopes displaying divergent in vivo function. These results should facilitate further studies of the in vivo effects of DENV-specific T cells, including the use of genetically modified mouse strains.

  1. In vitro and in vivo analyses of a genetically—restricted antigen specific factor from mixed cell cultures of macrophage,T and B lymphocytes

    Institute of Scientific and Technical Information of China (English)

    CHAURMW; LAUASK

    1990-01-01

    An immunostimulatory factor was identified to be secreted by antigen-pulsed macrophages.This factor was able to induce the generation of antigen specific T helper lymphocytes in vitro as well as in vivo.Further in vitro experiments testing for the genetic restriction of this factor indicated that it is a geneticallyrestricted antigen specific factor (ASF).The Cunningham plaque assay was used to quantify the generation of T helper lymphocytes by measuring the number of plaque forming cells after sequential incubations of antigen-qulsed macrophages with T lymphocytes,and then spleen cells,and finally the TNP-coated sheep red blood cells.

  2. MHC-I-restricted epitopes conserved among variola and other related orthopoxviruses are recognized by T cells 30 years after vaccination

    DEFF Research Database (Denmark)

    Tang, Sheila Tuyet; Wang, M.; Lamberth, K.;

    2008-01-01

    It is many years since the general population has been vaccinated against smallpox virus. Here, we report that human leukocyte antigen (HLA) class I restricted T cell epitopes can be recognized more than 30 years after vaccination. Using bioinformatic methods, we predicted 177 potential cytotoxic...... to a better understanding of poxvirus immunity and may aid in the development of new improved vaccines and diagnostic tools.......It is many years since the general population has been vaccinated against smallpox virus. Here, we report that human leukocyte antigen (HLA) class I restricted T cell epitopes can be recognized more than 30 years after vaccination. Using bioinformatic methods, we predicted 177 potential cytotoxic T...... lymphocyte epitopes. Eight epitopes were confirmed to stimulate IFN-gamma release by T cells in smallpox-vaccinated subjects. The epitopes were restricted by five supertypes (HLA-A1, -A2, -A24 -A26 and -B44). Significant T cell responses were detected against 8 of 45 peptides with an HLA class I affinity...

  3. Multifunctional cytomegalovirus (CMV)-specific CD8(+) T cells are not restricted by telomere-related senescence in young or old adults.

    Science.gov (United States)

    Riddell, Natalie E; Griffiths, Stephen J; Rivino, Laura; King, David C B; Teo, Guo H; Henson, Sian M; Cantisan, Sara; Solana, Rafael; Kemeny, David M; MacAry, Paul A; Larbi, Anis; Akbar, Arne N

    2015-04-01

    Antigen-specific multifunctional T cells that secrete interferon-γ, interleukin-2 and tumour necrosis factor-α simultaneously after activation are important for the control of many infections. It is unclear if these CD8(+) T cells are at an early or late stage of differentiation and whether telomere erosion restricts their replicative capacity. We developed a multi-parameter flow cytometric method for investigating the relationship between differentiation (CD45RA and CD27 surface phenotype), function (cytokine production) and replicative capacity (telomere length) in individual cytomegalovirus (CMV) antigen-specific CD8(+) T cells. This involves surface and intracellular cell staining coupled to fluorescence in situ hybridization to detect telomeres (flow-FISH). The end-stage/senescent CD8(+)  CD45RA(+)  CD27(-) T-cell subset increases significantly during ageing and this is exaggerated in CMV immune-responsive subjects. However, these end-stage cells do not have the shortest telomeres, implicating additional non-telomere-related mechanisms in inducing their senescence. The telomere lengths in total and CMV (NLV)-specific CD8(+) T cells in all four subsets defined by CD45RA and CD27 expression were significantly shorter in old compared with young individuals in both a Caucasian and an Asian cohort. Following stimulation by anti-CD3 or NLV peptide, similar proportions of triple-cytokine-producing cells are found in CD8(+) T cells at all stages of differentiation in both age groups. Furthermore, these multi-functional cells had intermediate telomere lengths compared with cells producing only one or two cytokines after activation. Therefore, global and CMV (NLV)-specific CD8(+) T cells that secrete interferon-γ, interleukin-2 and tumour necrosis factor-α are at an intermediate stage of differentiation and are not restricted by excessive telomere erosion.

  4. Investigation of Abscopal and Bystander Effects in Immunocompromised Mice After Exposure to Pencilbeam and Microbeam Synchrotron Radiation.

    Science.gov (United States)

    Fernandez-Palomo, Cristian; Schültke, Elisabeth; Bräuer-Krisch, Elke; Laissue, Jean Albert; Blattmann, Hans; Seymour, Colin; Mothersill, Carmel

    2016-08-01

    Out-of-field effects are of considerable interest in radiotherapy. The mechanisms are poorly understood but are thought to involve signaling processes, which induce responses in non-targeted cells and tissues. The immune response is thought to play a role. The goal of this research was to study the induction of abscopal effects in the bladders of NU-Foxn1 mice after irradiating their brains using Pencil Beam (PB) or microbeam (MRT) irradiation at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Athymic nude mice injected with F98 glioma cells into their right cerebral hemisphere 7 d earlier were treated with either MRT or PB. After recovery times of 2, 12, and 48 h, the urinary bladders were extracted and cultured as tissue explants for 24 h. The growth medium containing the potential signaling factors was harvested, filtered, and transferred to HaCaT reporter cells to assess their clonogenic survival and calcium signaling potential. The results show that in the tumor-free mice, both treatment modalities produce strong bystander/abscopal signals using the clonogenic reporter assay; however, the calcium data do not support a calcium channel mediated mechanism. The presence of a tumor reduces or reverses the effect. PB produced significantly stronger effects in the bladders of tumor-bearing animals. The authors conclude that immunocompromised mice produce signals, which can alter the response of unirradiated reporter cells; however, a novel mechanism appears to be involved.

  5. MHC class II restricted innate-like double negative T cells contribute to optimal primary and secondary immunity to Leishmania major.

    Directory of Open Access Journals (Sweden)

    Zhirong Mou

    2014-09-01

    Full Text Available Although it is generally believed that CD4(+ T cells play important roles in anti-Leishmania immunity, some studies suggest that they may be dispensable, and that MHC II-restricted CD3(+CD4(-CD8(- (double negative, DN T cells may be more important in regulating primary anti-Leishmania immunity. In addition, while there are reports of increased numbers of DN T cells in Leishmania-infected patients, dogs and mice, concrete evidence implicating these cells in secondary anti-Leishmania immunity has not yet been documented. Here, we report that DN T cells extensively proliferate and produce effector cytokines (IFN-γ, TNF and IL-17 and granzyme B (GrzB in the draining lymph nodes and spleens of mice following primary and secondary L. major infections. DN T cells from healed mice display functional characteristics of protective anti-Leishmania memory-like cells: rapid and extensive proliferation and effector cytokines production following L. major challenge in vitro and in vivo. DN T cells express predominantly (> 95% alpha-beta T cell receptor (αβ TCR, are Leishmania-specific, restricted mostly by MHC class II molecules and display transcriptional profile of innate-like genes. Using in vivo depletion and adoptive transfer studies, we show that DN T cells contribute to optimal primary and secondary anti-Leishmania immunity in mice. These results directly identify DN T cells as important players in effective and protective primary and secondary anti-L. major immunity in experimental cutaneous leishmaniasis.

  6. Calorie restriction and stroke

    Directory of Open Access Journals (Sweden)

    Manzanero Silvia

    2011-09-01

    Full Text Available Abstract Stroke, a major cause of disability and mortality in the elderly, occurs when a cerebral blood vessel is occluded or ruptured, resulting in ischemic damage and death of brain cells. The injury mechanism involves metabolic and oxidative stress, excitotoxicity, apoptosis and inflammatory processes, including activation of glial cells and infiltration of leukocytes. In animal models, dietary energy restriction, by daily calorie reduction (CR or intermittent fasting (IF, extends lifespan and decreases the development of age-related diseases. Dietary energy restriction may also benefit neurons, as suggested by experimental evidence showing that CR and IF protect neurons against degeneration in animal models. Recent findings by our group and others suggest the possibility that dietary energy restriction may protect against stroke induced brain injury, in part by inducing the expression of neurotrophic factors, such as brain-derived neurotrophic factor (BDNF and basic fibroblast growth factor (bFGF; protein chaperones, including heat shock protein 70 (Hsp70 and glucose regulated protein 78 (GRP78; antioxidant enzymes, such as superoxide dismutases (SOD and heme oxygenase-1 (HO-1, silent information regulator T1 (SIRT1, uncoupling proteins and anti-inflammatory cytokines. This article discusses the protective mechanisms activated by dietary energy restriction in ischemic stroke.

  7. Human HLA-A*02:01/CHM1+ allo-restricted T cell receptor transgenic CD8+ T cells specifically inhibit Ewing sarcoma growth in vitro and in vivo.

    Science.gov (United States)

    Blaeschke, Franziska; Thiel, Uwe; Kirschner, Andreas; Thiede, Melanie; Rubio, Rebeca Alba; Schirmer, David; Kirchner, Thomas; Richter, Günther H S; Mall, Sabine; Klar, Richard; Riddell, Stanley; Busch, Dirk H; Krackhardt, Angela; Grunewald, Thomas G P; Burdach, Stefan

    2016-07-12

    The endochondral bone protein Chondromodulin-I (CHM1) provides oncogene addiction in Ewing sarcoma (ES). We pre-clinically tested the targetability of CHM1 by TCR transgenic, allo-restricted, peptide specific T cells to treat ES. We previously generated allo-restricted wildtype CD8+ T cells directed against the ES specific antigen CHM1319 causing specific responses against ES. However, utilization of these cells in current therapy protocols is hampered due to high complexity in production, relatively low cell numbers, and rapid T cell exhaustion.In order to provide off-the-shelf products in the future, we successfully generated HLA-A*02:01-restricted T cell receptor (TCR) transgenic T cells directed against CHM1319 by retroviral transduction.After short-term expansion a 100% purified CHM1319-TCR-transgenic T cell population expressed a CD62L+/CD45RO and CD62L+/CD45RA+ phenotype. These cells displayed specific in vitro IFNg and granzyme B release in co-culture with HLA-A*02:01+ ES cell lines expressing CHM1. When co-injected with ES cells in Rag2-/-É£c-/- mice, CHM1-specific TCR-transgenic T cells significantly inhibited the formation of lung and liver metastases in contrast to control mice. Lungs and livers of representative mice displayed CD8+ T cell infiltration in the presence (control group treated with unspecific T cells) and in the absence (study group) of metastatic disease, respectively. Furthermore, mice receiving unspecific T cells showed signs of graft-versus-host-disease in contrast to all mice, receiving CHM1319-TCR-transgenic T cells.CHM1319 specific TCR-transgenic T cells were successfully generated causing anti-ES responses in vitro and in vivo. In the future, CHM1319-TCR-transgenic T cells may control minimal residual disease rendering donor lymphocyte infusions more efficacious and less toxic.

  8. Regions of High Out-Of-Hospital Cardiac Arrest Incidence and Low Bystander CPR Rates in Victoria, Australia

    Science.gov (United States)

    Straney, Lahn D.; Bray, Janet E.; Beck, Ben; Finn, Judith; Bernard, Stephen; Dyson, Kylie; Lijovic, Marijana; Smith, Karen

    2015-01-01

    Background Out-of-hospital cardiac arrest (OHCA) remains a major public health issue and research has shown that large regional variation in outcomes exists. Of the interventions associated with survival, the provision of bystander CPR is one of the most important modifiable factors. The aim of this study is to identify census areas with high incidence of OHCA and low rates of bystander CPR in Victoria, Australia Methods We conducted an observational study using prospectively collected population-based OHCA data from the state of Victoria in Australia. Using ArcGIS (ArcMap 10.0), we linked the location of the arrest using the dispatch coordinates (longitude and latitude) to Victorian Local Government Areas (LGAs). We used Bayesian hierarchical models with random effects on each LGA to provide shrunken estimates of the rates of bystander CPR and the incidence rates. Results Over the study period there were 31,019 adult OHCA attended, of which 21,436 (69.1%) cases were of presumed cardiac etiology. Significant variation in the incidence of OHCA among LGAs was observed. There was a 3 fold difference in the incidence rate between the lowest and highest LGAs, ranging from 38.5 to 115.1 cases per 100,000 person-years. The overall rate of bystander CPR for bystander witnessed OHCAs was 62.4%, with the rate increasing from 56.4% in 2008–2010 to 68.6% in 2010–2013. There was a 25.1% absolute difference in bystander CPR rates between the highest and lowest LGAs. Conclusion Significant regional variation in OHCA incidence and bystander CPR rates exists throughout Victoria. Regions with high incidence and low bystander CPR participation can be identified and would make suitable targets for interventions to improve CPR participation rates. PMID:26447844

  9. Regions of High Out-Of-Hospital Cardiac Arrest Incidence and Low Bystander CPR Rates in Victoria, Australia.

    Directory of Open Access Journals (Sweden)

    Lahn D Straney

    Full Text Available Out-of-hospital cardiac arrest (OHCA remains a major public health issue and research has shown that large regional variation in outcomes exists. Of the interventions associated with survival, the provision of bystander CPR is one of the most important modifiable factors. The aim of this study is to identify census areas with high incidence of OHCA and low rates of bystander CPR in Victoria, Australia.We conducted an observational study using prospectively collected population-based OHCA data from the state of Victoria in Australia. Using ArcGIS (ArcMap 10.0, we linked the location of the arrest using the dispatch coordinates (longitude and latitude to Victorian Local Government Areas (LGAs. We used Bayesian hierarchical models with random effects on each LGA to provide shrunken estimates of the rates of bystander CPR and the incidence rates.Over the study period there were 31,019 adult OHCA attended, of which 21,436 (69.1% cases were of presumed cardiac etiology. Significant variation in the incidence of OHCA among LGAs was observed. There was a 3 fold difference in the incidence rate between the lowest and highest LGAs, ranging from 38.5 to 115.1 cases per 100,000 person-years. The overall rate of bystander CPR for bystander witnessed OHCAs was 62.4%, with the rate increasing from 56.4% in 2008-2010 to 68.6% in 2010-2013. There was a 25.1% absolute difference in bystander CPR rates between the highest and lowest LGAs.Significant regional variation in OHCA incidence and bystander CPR rates exists throughout Victoria. Regions with high incidence and low bystander CPR participation can be identified and would make suitable targets for interventions to improve CPR participation rates.

  10. Bystander Action in Situations of Dating and Sexual Aggression: A Mixed Methodological Study of High School Youth.

    Science.gov (United States)

    Edwards, Katie M; Rodenhizer-Stämpfli, Kara Anne; Eckstein, Robert P

    2015-12-01

    Bystander action is a critical component of dating and sexual aggression prevention; however, little is known about barriers and facilitators of bystander action among high school youth and in what situations youth are willing to engage in bystander action. The current study examined bystander action in situations of dating and sexual aggression using a mixed methodological design. Participants included primarily Caucasian (83.0%, n = 181) male (54.6%, n = 119) and female (44.5%, n = 97) high school youth (N = 218). Most (93.6%) students had the opportunity to take action during the past year in situations of dating or sexual aggression; being female and histories of dating and sexual aggression related to bystander action. Thematic analysis of the focus group data identified barriers (e.g., the aggression not meeting a certain threshold, anticipated negative consequences) to bystander action, as well as insight on promising forms of action (e.g., verbally telling the perpetrator to stop, getting a teacher); problematic intervention methods (e.g., threatening or using physical violence to stop the perpetrator) were also noted. Implications for programming are discussed.

  11. Cost-effective screening methods for various single gene defects in single cells using high magnesium and total ionic strength and restriction enzymes.

    Science.gov (United States)

    Tsai, Y H

    2000-12-01

    A reliable cost-effective protocol for the diagnosis of various defective genes in single blastomeres from preimplantation embryos has been established. Single cells were lysed in alkali buffer followed by neutralization and addition of a solution containing a high concentration of sulfhydryl reducing agents and MgCl(2) in relatively high ionic strength (0.45) (solution M) with or without restriction enzyme(s). The reaction mixture was incubated at 37 degrees C for 15 min followed by heat denaturation at 95 degrees C for 10 min. Respective polymerase chain reaction (PCR) mixture was then added to amplify each designated DNA region. The treatment of neutralized single cell lysate with adequate restriction enzyme(s) which do not cleave the target DNA sequences but shortens the genomic template DNA strands. This may facilitate primer-template annealing. The subsequent heat denaturation of the cell lysate in solution M indeed gave better signals of amplified DNA fragments on polyacrylamide gels. Defects in Tay Sachs exons 11 and 12, CF-DeltaF508 and CF-N1303K, and genomic sequences of ZFX/ZFY were successfully detected on gels after one-step PCR amplification, especially those cell lysates treated with restriction enzymes. In conclusion, a cost-effective one-step PCR method for amplifying various specific genomic regions containing a single gene defect in single cells has been established. This protocol may be applied to genetic screening for many single defective genes of biopsied single blastomeres from preimplantation in vitro fertilization (IVF) embryos.

  12. Peptide-loaded dendritic cells prime and activate MHC-class I-restricted T cells more efficiently than protein-loaded cross-presenting DC

    DEFF Research Database (Denmark)

    Met, Ozcan; Buus, Søren; Claesson, Mogens H

    2003-01-01

    -pulsed DC. Moreover, SIINFEKL-loaded DC were up to 50 times more efficient than DC-pulsed with OVA-protein for generation of an H-2K(b)-restricted response. Immunization of mice with SIINFEKL-loaded DC resulted in a much stronger H-2K(b)-restricted response than immunization with OVA-pulsed DC. These data...

  13. Endogenous origins of HIV-1 G-to-A hypermutation and restriction in the nonpermissive T cell line CEM2n.

    Directory of Open Access Journals (Sweden)

    Eric W Refsland

    Full Text Available The DNA deaminase APOBEC3G converts cytosines to uracils in retroviral cDNA, which are immortalized as genomic strand G-to-A hypermutations by reverse transcription. A single round of APOBEC3G-dependent mutagenesis can be catastrophic, but evidence suggests that sublethal levels contribute to viral genetic diversity and the associated problems of drug resistance and immune escape. APOBEC3G exhibits an intrinsic preference for the second cytosine in a 5'CC dinucleotide motif leading to 5'GG-to-AG mutations. However, an additional hypermutation signature is commonly observed in proviral sequences from HIV-1 infected patients, 5'GA-to-AA, and it has been attributed controversially to one or more of the six other APOBEC3 deaminases. An unambiguous resolution of this problem has been difficult to achieve, in part due to dominant effects of protein over-expression. Here, we employ gene targeting to dissect the endogenous APOBEC3 contribution to Vif-deficient HIV-1 restriction and hypermutation in a nonpermissive T cell line CEM2n. We report that APOBEC3G-null cells, as predicted from previous studies, lose the capacity to inflict 5'GG-to-AG mutations. In contrast, APOBEC3F-null cells produced viruses with near-normal mutational patterns. Systematic knockdown of other APOBEC3 genes in an APOBEC3F-null background revealed a significant contribution from APOBEC3D in promoting 5'GA-to-AA hypermutations. Furthermore, Vif-deficient HIV-1 restriction was strong in parental CEM2n and APOBEC3D-knockdown cells, partially alleviated in APOBEC3G- or APOBEC3F-null cells, further alleviated in APOBEC3F-null/APOBEC3D-knockdown cells, and alleviated to the greatest extent in APOBEC3F-null/APOBEC3G-knockdown cells revealing clear redundancy in the HIV-1 restriction mechanism. We conclude that endogenous levels of APOBEC3D, APOBEC3F, and APOBEC3G combine to restrict Vif-deficient HIV-1 and cause the hallmark dinucleotide hypermutation patterns in CEM2n. Primary T

  14. A novel lineage transcription factor based analysis reveals differences in T helper cell subpopulation development in infected and intrauterine growth restricted (IUGR) piglets.

    Science.gov (United States)

    Ebner, F; Rausch, S; Scharek-Tedin, L; Pieper, R; Burwinkel, M; Zentek, J; Hartmann, S

    2014-10-01

    Research in mouse and human clearly identified subsets of T helper (Th) cells based on nuclear expression of specific lineage transcription factors. In swine, however, transcription factor based detection of functional subpopulations of porcine Th cells by flow cytometry is so far limited to regulatory T cells via Foxp3. T-bet and GATA-3 are the transcription factors that regulate commitment to Th1 or Th2 cells, respectively. In this study we prove GATA-3 and T-bet expression in porcine CD4(+) cells polarized in vitro. Importantly, GATA-3 and T-bet expressing cells were detectable in pigs infected with pathogens associated with Th2 and Th1 immune responses. Increased frequencies of GATA-3 positive CD4(+) cells are found in vivo in pigs experimentally infected with the nematode Trichuris suis, whereas porcine reproductive and respiratory syndrome virus (PRRSV) infection elicited T-bet positive CD4(+) T cells. Analysing the immune status of pre-weaning piglets with intrauterine growth restriction (IUGR) we found an increased expression of Foxp3, T-bet and GATA-3 in CD4(+) and CD4(+)CD8(+) double-positive T cells in systemic and intestinal compartments of IUGR piglets. Hence, we established the detection of porcine Th1 and Th2 cells via T-bet and GATA-3 and show that the porcine lineage transcription factors are differentially regulated very early in life depending on the developmental status.

  15. B-cell responses to pregnancy-restricted and -unrestricted Plasmodium falciparum erythrocyte membrane protein 1 antigens in Ghanaian women naturally exposed to malaria parasites

    DEFF Research Database (Denmark)

    Ampomah, Paulina; Stevenson, Liz; Ofori, Michael F;

    2014-01-01

    -linked immunosorbent assay (ELISA) and memory B-cell frequencies by enzyme-linked immunosorbent spot (ELISPOT) assay in a cohort of P. falciparum-exposed nonpregnant Ghanaian women. The antigens used were a VAR2CSA-type PfEMP1 (IT4VAR04) with expression restricted to parasites infecting the placenta, as well as two...... immunity probably reflect the clonal antigenic variation and allelic polymorphism of PfEMP1. However, it is likely that other immune-evasive mechanisms are also involved, such as interference with formation and maintenance of immunological memory. We measured PfEMP1-specific antibody levels by enzyme...... commonly recognized PfEMP1 proteins (HB3VAR06 and IT4VAR60) implicated in rosetting and not pregnancy restricted. This enabled, for the first time, a direct comparison in the same individuals of immune responses specific for a clinically important parasite antigen expressed only during well-defined periods...

  16. Induction of an antitumor response using dendritic cells transfected with DNA constructs encoding the HLA-A*02:01-restricted epitopes of tumor-associated antigens in culture of mononuclear cells of breast cancer patients.

    Science.gov (United States)

    Sennikov, Sergey Vital'evich; Shevchenko, Julia Alexandrovna; Kurilin, Vasilii Vasil'evich; Khantakova, Julia Nikolaevna; Lopatnikova, Julia Anatol'evna; Gavrilova, Elena Vasil'evna; Maksyutov, Rinat Amirovich; Bakulina, Anastasiya Yur'evna; Sidorov, Sergey Vasil'evich; Khristin, Alexander Alexandrovich; Maksyutov, Amir Zakievich

    2016-02-01

    Advances in oncoimmunology related to the definition of the basic mechanisms of the formation of antitumor immune response, as well as the opening of tumor-associated antigens recognized by immune cells, allowed to start developing ways to influence the effector cells of the immune system to generate effective antitumor cytotoxic response. We investigated the possibility to stimulate an antitumor response in a culture of mononuclear cells of breast cancer patients by dendritic cells transfected with HLA-A*02:01-restricted DNA constructs. We isolated dendritic cells from peripheral blood monocytes and delivered our constructs to these cells by magnetic transfection. Additionally, a series of experiments with loading of dendritic cells with autologous tumor cell lysate antigens was conducted. We have shown that dendritic cells transfected with the HLA-A*02:01-restricted DNA constructs are effective in inducing an antitumor response in a culture of mononuclear cells of breast cancer patients. Dendritic cells transfected with DNA constructor dendritic cells loaded with lysate antigens revealed a comparable stimulated cytotoxic response of mononuclear cells to these two ways of antigen delivery. We conclude that using DNA constructs in conjunction with patient stratification by HLA type allows the application of transfected DCs as an effective method to stimulate antitumor immunity in vitro.

  17. Early-age feed restriction affects viability and gene expression of satellite cells isolated from the gastrocnemius muscle of broiler chicks

    Directory of Open Access Journals (Sweden)

    Li Yue

    2012-11-01

    Full Text Available Abstract Background Muscle growth depends on the fusion of proliferate satellite cells to existing myofibers. We reported previously that 0–14 day intermittent feeding led to persistent retardation in myofiber hypertrophy. However, how satellite cells respond to such nutritional insult has not been adequately elucidated. Results One-day-old broiler chicks were allocated to control (Con, ad libitum feeding, intermittent feeding (IF, feed provided on alternate days and re-feeding (RF, 2 days ad libitum feeding after 12 days of intermittent feeding groups. Chickens were killed on Day 15 and satellite cells were isolated. When cultured, satellite cells from the IF group demonstrated significant retardation in proliferation and differentiation potential, while RF partly restored the proliferation rate and differentiation potential of the satellite cells. Significant up-regulation of insulin like growth factor I receptor (IGF-IR (P0.05 and thyroid hormone receptor α (TRα (P0.05, and down-regulation of growth hormone receptor (GHR (P0.01 and IGF-I (P0.01 mRNA expression was observed in freshly isolated IF satellite cells when compared with Con cells. In RF cells, the mRNA expression of IGF-I was higher (P0.05 and of TRα was lower (P0.01 than in IF cells, suggesting that RF restored the mRNA expression of TRα and IGF-I, but not of GHR and IGF-IR. The Bax/Bcl-2 ratio tended to increase in the IF group, which was reversed in the RF group (P0.05, indicating that RF reduced the pro-apoptotic influence of IF. Moreover, no significant effect of T3 was detected on cell survival in IF cells compared with Con (PP0.05 cells. Conclusions These data suggest that early-age feed restriction inhibits the proliferation and differentiation of satellite cells, induces changes in mRNA expression of the GH/IGF-I and thyroid hormone receptors in satellite cells, as well as blunted sensitivity of satellite cells to T3, and that RF partially reverses these effects. Thus

  18. Oxidative stress as a significant factor for development of an adaptive response in irradiated and nonirradiated human lymphocytes after inducing the bystander effect by low-dose X-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ermakov, Aleksei V., E-mail: avePlato@mail.ru [Research Centre for Medical Genetics, Russian Academy of Medical Science, ul. Moskvorechye, 1, Moscow 115478 (Russian Federation); Konkova, Marina S.; Kostyuk, Svetlana V.; Egolina, Natalya A.; Efremova, Liudmila V.; Veiko, Natalya N. [Research Centre for Medical Genetics, Russian Academy of Medical Science, ul. Moskvorechye, 1, Moscow 115478 (Russian Federation)

    2009-10-02

    X-radiation (10 cGy) was shown to induce in human lymphocytes transposition of homologous chromosomes loci from the membrane towards the centre of the nucleus and activation of the chromosomal nucleolus-forming regions (NFRs). These effects are transmitted by means of extracellular DNA (ecDNA) fragments to nonirradiated cells (the so-called bystander effect, BE). We demonstrated that in the development of the BE an important role is played by oxidative stress (which is brought about by low radiation doses and ecDNA fragments of the culture medium of the irradiated cells), by an enzyme of apoptosis called caspase-3, and by DNA-binding receptors of the bystander cells, presumably TLR9. Proposed herein is a scheme of the development of an adaptive response and the BE on exposure to radiation. Ionizing radiation induces apoptosis of the radiosensitive fraction of cells due to the development of the 'primary' oxidative stress (OS). DNA fragments of apoptotic cells are released into the intercellular space and interact with the DNA-binding receptors of the bystander cells. This interaction activates in lymphocytes signalling pathways associated with synthesis of the reactive oxygen species and nitrogen species, i.e., induces secondary oxidative stress accompanied by apoptosis of part of the cells, etc. Hence, single exposure to radiation may be followed by relatively long-lasting in the cellular population oxidative stress contributing to the development of an adaptive response. We thus believe that ecDNA of irradiated apoptotic lymphocytes is a significant factor of stress-signalling.

  19. The effect of victims' responses to overt bullying on same-sex peer bystander reactions.

    Science.gov (United States)

    Sokol, Nicole; Bussey, Kay; Rapee, Ronald M

    2015-10-01

    This study investigated the impact of victims' responses to overt bullying on peer bystanders' attitudes and reactions. Fifth- and seventh-grade students (N = 206; M(age) = 11.13 and 13.18 years, respectively) completed online questionnaires about gender-consistent videotaped hypothetical bullying scenarios in which the victims' responses (angry, sad, confident, ignoring) were experimentally manipulated. Victims' responses significantly influenced bystanders' attitudes towards the victim, perceptions of the victimization, emotional reactions, and behavioral intentions. In general, angry victims elicited more negative reactions, sad victims elicited greater intentions to act, while incidents involving confident victims were perceived as less serious. Several variations depending on the bullying type and students' grade, gender, and personal experiences with bullying were evident. Implications for individual-level and peer-level anti-bullying interventions are discussed.

  20. Bystanders matter: associations between reinforcing, defending, and the frequency of bullying behavior in classrooms.

    Science.gov (United States)

    Salmivalli, Christina; Voeten, Marinus; Poskiparta, Elisa

    2011-01-01

    This study investigated whether the bystanders' behaviors (reinforcing the bully vs. defending the victim) in bullying situations are related to the frequency of bullying in a classroom. The sample consisted of 6,764 primary school children from Grades 3 to 5 (9-11 years of age), who were nested within 385 classrooms in 77 schools. The students filled out Internet-based questionnaires in their schools' computer labs. The results from multilevel models showed that defending the victim was negatively associated with the frequency of bullying in a classroom, whereas the effect of reinforcing the bully was positive and strong. The results suggest that bystander responses influence the frequency of bullying, which makes them suitable targets for antibullying interventions.

  1. The Presence of HLA-E-Restricted, CMV-Specific CD8+ T Cells in the Blood of Lung Transplant Recipients Correlates with Chronic Allograft Rejection.

    Directory of Open Access Journals (Sweden)

    Lucy C Sullivan

    Full Text Available The human cytomegalovirus (CMV immune evasion protein, UL40, shares an identical peptide sequence with that found in the leader sequence of many human leukocyte antigen (HLA-C alleles and when complexed with HLA-E, can modulate NK cell functions via interactions with the CD94-NKG2 receptors. However the UL40-derived sequence can also be immunogenic, eliciting robust CD8+ T cell responses. In the setting of solid organ transplantation these T cells may not only be involved in antiviral immunity but also can potentially contribute to allograft rejection when the UL40 epitope is also present in allograft-encoded HLA. Here we assessed 15 bilateral lung transplant recipients for the presence of HLA-E-restricted UL40 specific T cells by tetramer staining of peripheral blood mononuclear cells (PBMC. UL40-specific T cells were observed in 7 patients post-transplant however the magnitude of the response varied significantly between patients. Moreover, unlike healthy CMV seropositive individuals, longitudinal analyses revealed that proportions of such T cells fluctuated markedly. Nine patients experienced low-grade acute cellular rejection, of which 6 also demonstrated UL40-specific T cells. Furthermore, the presence of UL40-specific CD8+ T cells in the blood was significantly associated with allograft dysfunction, which manifested as Bronchiolitis Obliterans Syndrome (BOS. Therefore, this study suggests that minor histocompatibility antigens presented by HLA-E can represent an additional risk factor following lung transplantation.

  2. Polycomb group genes Psc and Su(z)2 restrict follicle stem cell self-renewal and extrusion by controlling canonical and noncanonical Wnt signaling.

    Science.gov (United States)

    Li, Xinghua; Han, Yue; Xi, Rongwen

    2010-05-01

    Stem cells are critical for maintaining tissue homeostasis and are commonly governed by their niche microenvironment, although the intrinsic mechanisms controlling their multipotency are poorly understood. Polycomb group (PcG) genes are epigenetic silencers, and have emerged recently as important players in maintaining stem cell multipotency by preventing the initiation of differentiation programs. Here we describe an unexpected role of specific PcG genes in allowing adult stem cell differentiation and preventing stem cell-derived tumor development. We show that Posterior sex combs (Psc), which encodes a core Polycomb-repressive complex 1 (PRC1) component, functions redundantly with a similar gene, Suppressor of zeste two [Su(z)2], to restrict follicle stem cell (FSC) self-renewal in the Drosophila ovary. FSCs carrying deletion mutations of both genes extrude basally from the epithelium and continue to self-propagate at ectopic sites, leading to the development of FSC-like tumors. Furthermore, we show that the propagation of the mutant cells is driven by sustained activation of the canonical Wnt signaling pathway, which is essential for FSC self-renewal, whereas the epithelial extrusion is mediated through the planar cell polarity pathway. This study reveals a novel mechanism of epithelial extrusion, and indicates a novel role of polycomb function in allowing adult stem cell differentiation by antagonizing self-renewal programs. Given evolutionary conservation of PcG genes from Drosophila to mammals, they could have similar functions in mammalian stem cells and cancer.

  3. Restricted use of fetal VH3 immunoglobulin genes by unselected B cells in the adult. Predominance of 56p1-like VH genes in common variable immunodeficiency.

    Science.gov (United States)

    Braun, J; Berberian, L; King, L; Sanz, I; Govan, H L

    1992-05-01

    The large VH3 family of human immunoglobulin genes is commonly used throughout B cell ontogeny. However, B cells of the fetus and certain autoantibody-producing clones are restricted to a recurrent subset of VH3 genes, and VH3 B cells are deficient in certain immunodeficiency diseases. In this study, we have sequenced a set of rearranged VH3 genes generated by genomic polymerase chain reaction (PCR) from normal adults and those with common variable immunodeficiency (CVI). In both groups, all cones were readily identifiable with the fetal VH3 subset, and were further distinguished by limited DH motifs and exclusive use of JH4. In CVI, the residual population of VH3 B cells were notable for predominant use of 56p1-like VH genes. All clones displayed sequence divergence (including somatic mutation) with evidence of strong selection against complementarity-determining region (CDR) coding change. A survey of other V gene families indicates that human V gene diversity may be restricted in general by germline mechanisms. These findings suggest that the expressed antibody repertoire in the human adult may be much smaller than anticipated, and selected by processes in part distinct from the paradigm of maximal antigen-binding diversity.

  4. Teens’ Self-Efficacy to Deal with Dating Violence as Victim, Perpetrator or Bystander

    OpenAIRE

    Van Camp, T.; Hébert, M; E. Guidi; Lavoie, F.; M. Blais

    2014-01-01

    Multiple studies have demonstrated that adolescent dating violence is highly prevalent and associated with internalizing and externalizing problems. A number of prevention initiatives are being implemented in North-American high schools. Such initiatives do not only aim to raise awareness among potential victims and offenders but also among peer bystanders. Since teenagers mainly reach out to their peers when experiencing adversity, it is important to address adolescents’ efficiency to deal w...

  5. It's Not My Place: Formative Evaluation Research to Design a Bystander Intervention Campaign.

    Science.gov (United States)

    DeMaria, Andrea L; Sundstrom, Beth; Grzejdziak, Maja; Booth, Kathleen; Adams, Helen; Gabel, Colby; Cabot, Jeri

    2015-10-07

    Sexual misconduct remains a problem on college campuses despite years of documentation and research, and program development and implementation. The purpose of this study was to conduct systematic theory-based formative audience research to understand how college women and men make meaning of sexual assault and bystander intervention. A total of 69 men and women aged 18 to 24 years participated in eight gender-specific focus group discussions. A grounded theory approach was used to identify patterns and themes across the data. Themes emerging from the data included the following: (a) female participants' experiences of sexism and misogyny, (b) the myth that rape is falsely reported, (c) complex understandings of consent and entitlement, (d) the reluctance to stop someone from having a "good time," (e) the role of alcohol as a moderating factor in sexual misconduct and bystander intervention, and (f) preference for direct and impactful messaging. This study informs researchers and practitioners about college students' perceptions of, and experiences with, bystander intervention and sexual assault. Practitioners can use this information to develop effective mixed media, campus-wide social marketing campaigns.

  6. IgE production after antigen-specific and cognate activation of HLA-DPw4-restricted T-cell clones, by 78% of randomly selected B-cell donors

    NARCIS (Netherlands)

    Baselmans, PJ; Pollabauer, EM; van Reijsen, FC; Heystek, HC; Hren, A; Stumptner, P; Tilanus, MGJ; Vooijs, WC; Mudde, GC

    2000-01-01

    The frequency of expression of the MHC class II antigen, HLA-DPw4, in the caucasoid population is approximately 78%, and is unmatched by phenotypic frequencies of other HLA class II molecules. Here we describe three human Der-P1-specific T-cell clones (TCC), restricted by the HLA-DPw4-variant HLA-DP

  7. Restriction beyond the restriction point: mitogen requirement for G2 passage

    Directory of Open Access Journals (Sweden)

    te Riele Hein

    2006-05-01

    Full Text Available Abstract Cell proliferation is dependent on mitogenic signalling. When absent, normal cells cannot pass the G1 restriction point, resulting in cell cycle arrest. Passage through the G1 restriction point involves inactivation of the retinoblastoma protein family. Consequently, loss of the retinoblastoma protein family leads to loss of the G1 restriction point. Recent work in our lab has revealed that cells possess yet another mechanism that restricts proliferation in the absence of mitogens: arrest in the G2 phase of the cell cycle. Here, we discuss the similarities and differences between these restriction points and the roles of cyclin-dependent kinase inhibitors (CKIs herein.

  8. Pineal gland expression of the transcription factor Egr-1 is restricted to a population of glia that are distinct from nestin-immunoreactive cells.

    Science.gov (United States)

    Man, Pui-Sin; Carter, David A

    2008-02-01

    Egr-1 is a plasticity-related transcription factor that has been implicated in circadian regulation of the pineal gland. In the present study we have investigated the cellular expression pattern of Egr-1 in the adult rat pineal. Egr-1 protein is restricted to the nucleus of a sub-population of cells. These cells were characterised using a new transgenic rat model (egr-1-d2EGFP) in which green fluorescent protein is driven by the egr-1 promoter. Cellular filling by GFP revealed that Egr-1-positive cells exhibited processes, indicating a glial cell-type morphology. This was confirmed by co-localizing the GFP-filled processes with vimentin and S-100beta. However, GFP/Egr-1 is expressed in only a tiny minority of the previously identified Id-1/vimentin-positive glial cells and therefore represents a novel sub-set of this (GFAP-negative) glial population. We have also demonstrated for the first time an extensive network of nestin-positive cells throughout the adult pineal gland, however these cells do not co-express Egr-1. Our studies have therefore broadened our understanding of the cell populations that constitute the adult pineal. Cellular localization of Egr-1 has revealed that this factor does not appear to be directly involved in pinealocyte production of melatonin but is required in a sub-set of pineal glia.

  9. Gamma-aminobutyric acid agonist-induced alterations in the ultrastructure of cultured cerebellar granule cells is restricted to early development

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Belhage, B; Schousboe, A;

    1988-01-01

    The effect of 4,5,6,7-tetrahydroisoxazolo[5,4-c]-pyridin-3-ol (THIP) on the ultrastructural composition of cultured cerebellar granule cells was investigated during development by quantitative electron microscopy (morphometric analysis). Granule cells were exposed to THIP (150 microM) for 6 h after...... 7 and 14 days, respectively, in culture. THIP treatment of 7-day-old cultures led to a statistically significant increase in the cytoplasmic density of rough endoplasmic reticulum, Golgi apparatus, vesicles, and coated vesicles, whereas no significant increase in the cytoplasmic density...... of these organelles was observed in 14-day-old cultures exposed to THIP for 6 h. These findings show that the effect of THIP on the ultrastructural composition of cultured cerebellar granule cells is restricted to early development....

  10. The Drosophila insulin-degrading enzyme restricts growth by modulating the PI3K pathway in a cell-autonomous manner.

    Science.gov (United States)

    Galagovsky, Diego; Katz, Maximiliano J; Acevedo, Julieta M; Sorianello, Eleonora; Glavic, Alvaro; Wappner, Pablo

    2014-03-01

    Mammalian insulin-degrading enzyme (IDE) cleaves insulin, among other peptidic substrates, but its function in insulin signaling is elusive. We use the Drosophila system to define the function of IDE in the regulation of growth and metabolism. We find that either loss or gain of function of Drosophila IDE (dIDE) can restrict growth in a cell-autonomous manner by affecting both cell size and cell number. dIDE can modulate Drosophila insulin-like peptide 2 levels, thereby restricting activation of the phosphatidylinositol-3-phosphate kinase pathway and promoting activation of Drosophila forkhead box, subgroup O transcription factor. Larvae reared in high sucrose exhibit delayed developmental timing due to insulin resistance. We find that dIDE loss of function exacerbates this phenotype and that mutants display increased levels of circulating sugar, along with augmented expression of a lipid biosynthesis marker. We propose that dIDE is a modulator of insulin signaling and that its loss of function favors insulin resistance, a hallmark of diabetes mellitus type II.

  11. Inhibition of endogenous hydrogen sulfide production in clear-cell renal cell carcinoma cell lines and xenografts restricts their growth, survival and angiogenic potential.

    Science.gov (United States)

    Sonke, Eric; Verrydt, Megan; Postenka, Carl O; Pardhan, Siddika; Willie, Chantalle J; Mazzola, Clarisse R; Hammers, Matthew D; Pluth, Michael D; Lobb, Ian; Power, Nicholas E; Chambers, Ann F; Leong, Hon S; Sener, Alp

    2015-09-15

    Clear cell renal cell carcinoma (ccRCC) is characterized by Von Hippel-Lindau (VHL)-deficiency, resulting in pseudohypoxic, angiogenic and glycolytic tumours. Hydrogen sulfide (H2S) is an endogenously-produced gasotransmitter that accumulates under hypoxia and has been shown to be pro-angiogenic and cytoprotective in cancer. It was hypothesized that H2S levels are elevated in VHL-deficient ccRCC, contributing to survival, metabolism and angiogenesis. Using the H2S-specific probe MeRhoAz, it was found that H2S levels were higher in VHL-deficient ccRCC cell lines compared to cells with wild-type VHL. Inhibition of H2S-producing enzymes could reduce the proliferation, metabolism and survival of ccRCC cell lines, as determined by live-cell imaging, XTT/ATP assay, and flow cytometry respectively. Using the chorioallantoic membrane angiogenesis model, it was found that systemic inhibition of endogenous H2S production was able to decrease vascularization of VHL-deficient ccRCC xenografts. Endogenous H2S production is an attractive new target in ccRCC due to its involvement in multiple aspects of disease.

  12. Ancestral trees for modeling stem cell lineages genetically rather than functionally: understanding mutation accumulation and distinguishing the restrictive cancer stem cell propagation theory and the unrestricted cell propagation theory of human tumorigenesis.

    Science.gov (United States)

    Shibata, Darryl K; Kern, Scott E

    2008-01-01

    Cancer stem cells either could be rare or common in tumors, constituting the major distinction between the two fundamentally opposed theoretical models of tumor progression: A newer and restrictive stem cell propagation model, in which the stem cells are a small and special minority of the tumor cells, and a standard older model, an unrestricted cell proliferation theory, in which many or most tumor cells are capable of indefinite generations of cell division. Stem cells of tumors are difficult to quantitate using functional assays, and the validity of the most common assays is seriously questioned. Nonetheless, stem cells are an essential component of any tumorigenesis model. Alternative approaches to studying tumor stem cells should be explored. Cell populations can be conceived of as having a genealogy, a relationship of cells to their ancestral lineage, from the zygote to the adult cells or neoplasms. Models using ancestral trees thus offer an anatomic and genetic means to "observe" stem cells independent of artificial conditions. Ancestral trees broaden our attention backward along a lineage, to the zygote stage, and thereby add insight into how the mutations of tumors accumulate. It is possible that a large fraction of mutations in a tumor originate from normal, endogenous, replication errors (nearly all being passenger mutations) occurring prior to the emergence of the first transformed cell. Trees can be constructed from experimental measurements - molecular clocks - of real human tissues and tumors. Detailed analysis of single-cell methylation patterns, heritable yet slightly plastic, now can provide this information in the necessary depth. Trees based on observations of molecular clocks may help us to distinguish between competing theories regarding the proliferative properties among cells of actual human tumors, to observe subtle and difficult phenomena such as the extinction of stem lineages, and to address the origins and rates of mutations in various

  13. Human CD4(+) T Cell Responses to an Attenuated Tetravalent Dengue Vaccine Parallel Those Induced by Natural Infection in Magnitude, HLA Restriction, and Antigen Specificity.

    Science.gov (United States)

    Angelo, Michael A; Grifoni, Alba; O'Rourke, Patrick H; Sidney, John; Paul, Sinu; Peters, Bjoern; de Silva, Aruna D; Phillips, Elizabeth; Mallal, Simon; Diehl, Sean A; Kirkpatrick, Beth D; Whitehead, Stephen S; Durbin, Anna P; Sette, Alessandro; Weiskopf, Daniela

    2017-03-01

    Dengue virus (DENV) is responsible for growing numbers of infections worldwide and has proven to be a significant challenge for vaccine development. We previously demonstrated that CD8(+) T cell responses elicited by a dengue live attenuated virus (DLAV) vaccine resemble those observed after natural infection. In this study, we screened peripheral blood mononuclear cells (PBMCs) from donors vaccinated with a tetravalent DLAV vaccine (TV005) with pools of dengue virus-derived predicted major histocompatibility complex (MHC) class II binding peptides. The definition of CD4(+) T cell responses after live vaccination is important because CD4(+) T cells are known contributors to host immunity, including cytokine production, help for CD8(+) T and B cells, and direct cytotoxicity against infected cells. While responses to all antigens were observed, DENV-specific CD4(+) T cells were focused predominantly on the capsid and nonstructural NS3 and NS5 antigens. Importantly, CD4(+) T cell responses in vaccinees were similar in magnitude and breadth to those after natural infection, recognized the same antigen hierarchy, and had similar profiles of HLA restriction. We conclude that TV005 vaccination has the capacity to elicit CD4(+) cell responses closely mirroring those observed in a population associated with natural immunity.IMPORTANCE The development of effective vaccination strategies against dengue virus infection is of high global public health interest. Here we study the CD4 T cell responses elicited by a tetravalent live attenuated dengue vaccine and show that they resemble responses seen in humans naturally exposed to dengue virus. This is an important issue, since it is likely that optimal immunity induced by a vaccine requires induction of CD4(+) responses against the same antigens as those recognized as dominant in natural infection. Detailed knowledge of the T cell response may further contribute to the identification of robust correlates of protection against

  14. Restricted growth of U-type infectious haematopoietic necrosis virus (IHNV) in rainbow trout cells may be linked to casein kinase II activity

    Science.gov (United States)

    Park, J.-W.; Moon, C.H.; Harmache, A.; Wargo, A.R.; Purcell, M.K.; Bremont, M.; Kurath, G.

    2011-01-01

    Previously, we demonstrated that a representative M genogroup type strain of infectious haematopoietic necrosis virus (IHNV) from rainbow trout grows well in rainbow trout-derived RTG-2 cells, but a U genogroup type strain from sockeye salmon has restricted growth, associated with reduced genome replication and mRNA transcription. Here, we analysed further the mechanisms for this growth restriction of U-type IHNV in RTG-2 cells, using strategies that assessed differences in viral genes, host immune regulation and phosphorylation. To determine whether the viral glycoprotein (G) or non-virion (NV) protein was responsible for the growth restriction, four recombinant IHNV viruses were generated in which the G gene of an infectious IHNV clone was replaced by the G gene of U- or M-type IHNV and the NV gene was replaced by NV of U- or M-type IHNV. There was no significant difference in the growth of these recombinants in RTG-2 cells, indicating that G and NV proteins are not major factors responsible for the differential growth of the U- and M-type strains. Poly I:C pretreatment of RTG-2 cells suppressed the growth of both U- and M-type IHNV, although the M virus continued to replicate at a reduced level. Both viruses induced type 1 interferon (IFN1) and the IFN1 stimulated gene Mx1, but the expression levels in M-infected cells were significantly higher than in U-infected cells and an inhibitor of the IFN1-inducible protein kinase PKR, 2-aminopurine (2-AP), did not affect the growth of U- or M-type IHNV in RTG-2 cells. These data did not indicate a role for the IFN1 system in the restricted growth of U-type IHNV in RTG-2 cells. Prediction of kinase-specific phosphorylation sites in the viral phosphoprotein (P) using the NetPhosK program revealed differences between U- and M-type P genes at five phosphorylation sites. Pretreatment of RTG-2 cells with a PKC inhibitor or a p38MAPK inhibitor did not affect the growth of the U- and M-type viruses. However, 100 μm of the

  15. Restricted growth of U-type infectious haematopoietic necrosis virus (IHNV) in rainbow trout cells may be linked to casein kinase II activity.

    Science.gov (United States)

    Park, J W; Moon, C H; Harmache, A; Wargo, A R; Purcell, M K; Bremont, M; Kurath, G

    2011-02-01

    Previously, we demonstrated that a representative M genogroup type strain of infectious haematopoietic necrosis virus (IHNV) from rainbow trout grows well in rainbow trout-derived RTG-2 cells, but a U genogroup type strain from sockeye salmon has restricted growth, associated with reduced genome replication and mRNA transcription. Here, we analysed further the mechanisms for this growth restriction of U-type IHNV in RTG-2 cells, using strategies that assessed differences in viral genes, host immune regulation and phosphorylation. To determine whether the viral glycoprotein (G) or non-virion (NV) protein was responsible for the growth restriction, four recombinant IHNV viruses were generated in which the G gene of an infectious IHNV clone was replaced by the G gene of U- or M-type IHNV and the NV gene was replaced by NV of U- or M-type IHNV. There was no significant difference in the growth of these recombinants in RTG-2 cells, indicating that G and NV proteins are not major factors responsible for the differential growth of the U- and M-type strains. Poly I:C pretreatment of RTG-2 cells suppressed the growth of both U- and M-type IHNV, although the M virus continued to replicate at a reduced level. Both viruses induced type 1 interferon (IFN1) and the IFN1 stimulated gene Mx1, but the expression levels in M-infected cells were significantly higher than in U-infected cells and an inhibitor of the IFN1-inducible protein kinase PKR, 2-aminopurine (2-AP), did not affect the growth of U- or M-type IHNV in RTG-2 cells. These data did not indicate a role for the IFN1 system in the restricted growth of U-type IHNV in RTG-2 cells. Prediction of kinase-specific phosphorylation sites in the viral phosphoprotein (P) using the NetPhosK program revealed differences between U- and M-type P genes at five phosphorylation sites. Pretreatment of RTG-2 cells with a PKC inhibitor or a p38MAPK inhibitor did not affect the growth of the U- and M-type viruses. However, 100 μm of the

  16. Bacillus anthracis lethal toxin disrupts TCR signaling in CD1d-restricted NKT cells leading to functional anergy.

    Directory of Open Access Journals (Sweden)

    Sunil K Joshi

    2009-09-01

    Full Text Available Exogenous CD1d-binding glycolipid (alpha-Galactosylceramide, alpha-GC stimulates TCR signaling and activation of type-1 natural killer-like T (NKT cells. Activated NKT cells play a central role in the regulation of adaptive and protective immune responses against pathogens and tumors. In the present study, we tested the effect of Bacillus anthracis lethal toxin (LT on NKT cells both in vivo and in vitro. LT is a binary toxin known to suppress host immune responses during anthrax disease and intoxicates cells by protective antigen (PA-mediated intracellular delivery of lethal factor (LF, a potent metalloprotease. We observed that NKT cells expressed anthrax toxin receptors (CMG-2 and TEM-8 and bound more PA than other immune cell types. A sub-lethal dose of LT administered in vivo in C57BL/6 mice decreased expression of the activation receptor NKG2D by NKT cells but not by NK cells. The in vivo administration of LT led to decreased TCR-induced cytokine secretion but did not affect TCR expression. Further analysis revealed LT-dependent inhibition of TCR-stimulated MAP kinase signaling in NKT cells attributable to LT cleavage of the MAP kinase kinase MEK-2. We propose that Bacillus anthracis-derived LT causes a novel form of functional anergy in NKT cells and therefore has potential for contributing to immune evasion by the pathogen.

  17. CD8(+) T cells specific to a single Yersinia pseudotuberculosis epitope restrict bacterial replication in the liver but fail to provide sterilizing immunity.

    Science.gov (United States)

    Shen, Haiqian; Gonzalez-Juarbe, Norberto; Blanchette, Krystle; Crimmins, Gregory; Bergman, Molly A; Isberg, Ralph R; Orihuela, Carlos J; Dube, Peter H

    2016-09-01

    CD8(+) T cells use contact-dependent cytolysis of target cells to protect the host against intracellular pathogens. We have previously shown that CD8(+) T cells and perforin are required to protect against the extracellular pathogen Yersinia pseudotuberculosis. Here we establish an experimental system where CD8(+) T cells specific to a single model antigen are the only memory response present at time of challenge. Using mice immunized with a vaccine strain of Listeria monocytogenes that expresses secreted ovalbumin (Lm-OVA), we show that OVA-specific CD8(+) T cells are generated and provide limited protection against challenge with virulent OVA(+)Y. pseudotuberculosis. Perforin expression by OVA-specific CD8(+) T cells was required, as Lm-OVA-immunized perforin-deficient mice showed higher bacterial burden as compared to Lm-OVA-immunized perforin-sufficient mice. Surprisingly, antigen-specific T cell protection waned over time, as Lm-OVA-immune mice eventually succumbed to Yersinia infection. Kinetic analysis of infection in mice with and without OVA-specific CD8(+) T cells revealed that bacterial numbers increased sharply in OVA-naïve mice until death, while OVA-immune mice held bacterial burden to a lower level throughout the duration of illness until death. Clonal analysis of bacterial populations in OVA-naïve and OVA-immune mice at distinct time points revealed equivalent and severe bottle-neck effects for bacteria in both sets of mice immediately after intravenous challenge, demonstrating a dominant role for other aspects of the immune system regardless of CD8(+) T cell status. These studies indicate that CD8(+) T cells against a single antigen can restrict Y. pseudotuberculosis colonization in a perforin-dependent manner, but ultimately are insufficient in their ability to provide sterilizing immunity and protect against death.

  18. Utilization of replication-competent XMRV reporter-viruses reveals severe viral restriction in primary human cells.

    Directory of Open Access Journals (Sweden)

    Christina Martina Stürzel

    Full Text Available The gammaretrovirus termed xenotropic murine leukemia virus-related virus (XMRV was described to be isolated from prostate cancer tissue biopsies and from blood of patients suffering from chronic fatigue syndrome. However, many studies failed to detect XMRV and to verify these disease associations. Data suggesting the contamination of specimens in particular by PCR-based methods and recent reports demonstrating XMRV generation via recombination of two murine leukemia virus precursors raised serious doubts about XMRV being a genuine human pathogen. To elucidate cell tropism of XMRV, we generated replication competent XMRV reporter viruses encoding a green fluorescent protein or a secretable luciferase as tools to analyze virus infection of human cell lines or primary human cells. Transfection of proviral DNAs into LNCaP prostate cancer cells resulted in readily detectably reporter gene expression and production of progeny virus. Inoculation of known XMRV susceptible target cells revealed that these virions were infectious and expressed the reporter gene, allowing for a fast and highly sensitive quantification of XMRV infection. Both reporter viruses were capable of establishing a spreading infection in LNCaP and Raji B cells and could be easily passaged. However, after inoculation of primary human blood cells such as CD4 T cells, macrophages or dendritic cells, infection rates were very low, and a spreading infection was never established. In line with these results we found that supernatants derived from these XMRV infected primary cell types did not contain infectious virus. Thus, although XMRV efficiently replicated in some human cell lines, all tested primary cells were largely refractory to XMRV infection and did not support viral spread. Our results provide further evidence that XMRV is not a human pathogen.

  19. Secreted Vago restricts West Nile virus infection in Culex mosquito cells by activating the Jak-STAT pathway.

    Science.gov (United States)

    Paradkar, Prasad N; Trinidad, Lee; Voysey, Rhonda; Duchemin, Jean-Bernard; Walker, Peter J

    2012-11-13

    Although West Nile virus (WNV) and other arthropod-borne viruses are a major public health problem, the mechanisms of antiviral immunity in mosquitoes are poorly understood. Dicer-2, responsible for the RNAi-mediated response through the C-terminal RNase-III domain, also contains an N-terminal DExD/H-box helicase domain similar to mammalian RIG-I/MDA5 which, in Drosophila, was found to be required for activation of an antiviral gene, Vago. Here we show that the Culex orthologue of Vago (CxVago) is up-regulated in response to WNV infection in a Dicer-2-dependent manner. Further, our data show that CxVago is a secreted peptide that restricts WNV infection by activation of the Jak-STAT pathway. Thus, Vago appears to function as an IFN-like antiviral cytokine in mosquitoes.

  20. Bystander Position Taking in School Bullying: The Role of Positive Identity, Self-Efficacy, and Self-Determination

    Directory of Open Access Journals (Sweden)

    Sandra K. M. Tsang

    2011-01-01

    Full Text Available School bullying has become an explicit, burgeoning problem challenging the healthy development of children and adolescents in Hong Kong. Many bullying prevention and intervention programs focus on victims and bullies, with bystanders treated as either nonexistent or irrelevant. This paper asserts that bystanders actually play pivotal roles in deciding whether the bullying process and dynamics are benign or adversarial. Bystanders' own abilities and characteristics often influence how they respond to victims and bullies. “P.A.T.H.S. to Adulthood: A Jockey Club Youth Enhancement Scheme” (P.A.T.H.S. = Positive Adolescent Training through Holistic Social Programmes is an evidence-based positive youth development program which shows that primary intervention programs have constructive impacts on junior secondary school students' beliefs and behavior. This paper asserts that intrapsychic qualities, namely identity, self-efficacy, and self-determination, greatly influence how bystanders react in school bullying situations. The paper also explains how classroom-based educational programs based on the P.A.T.H.S. model have been designed to help junior secondary school students strengthen these characteristics, so that they can be constructive bystanders when they encounter school bullying.

  1. Bystander position taking in school bullying: the role of positive identity, self-efficacy, and self-determination.

    Science.gov (United States)

    Tsang, Sandra K M; Hui, Eadaoin K P; Law, Bella C M

    2011-01-01

    School bullying has become an explicit, burgeoning problem challenging the healthy development of children and adolescents in Hong Kong. Many bullying prevention and intervention programs focus on victims and bullies, with bystanders treated as either nonexistent or irrelevant. This paper asserts that bystanders actually play pivotal roles in deciding whether the bullying process and dynamics are benign or adversarial. Bystanders' own abilities and characteristics often influence how they respond to victims and bullies. "P.A.T.H.S. to Adulthood: A Jockey Club Youth Enhancement Scheme" (P.A.T.H.S. = Positive Adolescent Training through Holistic Social Programmes) is an evidence-based positive youth development program which shows that primary intervention programs have constructive impacts on junior secondary school students' beliefs and behavior. This paper asserts that intrapsychic qualities, namely identity, self-efficacy, and self-determination, greatly influence how bystanders react in school bullying situations. The paper also explains how classroom-based educational programs based on the P.A.T.H.S. model have been designed to help junior secondary school students strengthen these characteristics, so that they can be constructive bystanders when they encounter school bullying.

  2. Inhibitory effects of apoptotic cell ingestion upon endotoxin-driven myeloid dendritic cell maturation.

    Science.gov (United States)

    Stuart, Lynda M; Lucas, Mark; Simpson, Cathy; Lamb, Jonathan; Savill, John; Lacy-Hulbert, Adam

    2002-02-15

    Dendritic cells (DCs) are the sentinels of the immune system, able to interact with both naive and memory T cells. The recent observation that DCs can ingest cells dying by apoptosis has raised the possibility that DCs may, in fact, present self-derived Ags, initiating both autoimmunity and tumor-specific responses, especially if associated with appropriate danger signals. Although the process of ingestion of apoptotic cells has not been shown to induce DC maturation, the exact fate of these phagocytosing DCs remains unclear. In this paper we demonstrate that DCs that ingest apoptotic cells are able to produce TNF-alpha but have a diminished ability to produce IL-12 in response to external stimuli, a property that corresponds to a failure to up-regulate CD86. By single-cell analysis we demonstrate that these inhibitory effects are restricted to those DCs that have engulfed apoptotic cells, with bystander DCs remaining unaffected. These changes were independent of the production of anti-inflammatory cytokines TGF-beta1 and IL-10 and corresponded with a diminished capacity to stimulate naive T cells. Thus, the ingestion of apoptotic cells is not an immunologically null event but is capable of modulating DC maturation. These results have important implications for our understanding of the role of clearance of dying cells by DCs not only in the normal resolution of inflammation but also in control of subsequent immune responses to apoptotic cell-derived Ags.

  3. The expression of a chimeric Phaseolus vulgaris nodulin 30-GUS gene is restricted to the rhizobially infected cells in transgenic Lotus corniculatus nodules.

    Science.gov (United States)

    Carsolio, C; Campos, F; Sánchez, F; Rocha-Sosa, M

    1994-12-01

    In Phaseolus vulgaris there is a nodulin family, Npv30, of ca. 30 kDa, as detected in an in vitro translation assay [2]. We isolated a gene (npv30-1) for one of the members of this family. The nucleotide sequence of the promoter of npv30-1 contains nodule-specific motifs common to other late nodulin genes. The promoter was fused to the GUS reporter gene; this chimeric fusion was introduced into Lotus corniculatus via Agrobacterium rhizogenes transformation. GUS activity was only detected in the infected cells of the nodules of transgenic plants. By contrast, the expression of a 35S-GUS construct was restricted to the uninfected cells and the vascular tissue.

  4. Adjuvanted HLA-supertype restricted subdominant peptides induce new T-cell immunity during untreated HIV-1-infection

    DEFF Research Database (Denmark)

    Karlsson, Ingrid; Brandt, Lea; Vinner, Lasse

    2013-01-01

    -cell responses specific for one or more vaccine epitopes were induced in 10/10 vaccinees. The responses were dominated by CD107a and MIP1β expression. There were no significant changes in HIV-1 viral load or CD4 T-cell counts. Our study demonstrates that the peptide/CAF01 vaccine is safe and that it is possible...

  5. Development of a diverse human T-cell repertoire despite stringent restriction of hematopoietic clonality in the thymus

    NARCIS (Netherlands)

    Brugman, Martijn H.; Wiekmeijer, Anna-Sophia; van Eggermond, Marja; Wolvers-Tettero, Ingrid; Langerak, Anton W.; de Haas, Edwin F. E.; Bystrykh, Leonid V.; van Rood, Jon J.; de Haan, Gerald; Fibbe, Willem E.; Staal, Frank J. T.

    2015-01-01

    The fate and numbers of hematopoietic stem cells (HSC) and their progeny that seed the thymus constitute a fundamental question with important clinical implications. HSC transplantation is often complicated by limited T-cell reconstitution, especially when HSC from umbilical cord blood are used. Att

  6. Progressive developmental restriction, acquisition of left-right identity and cell growth behavior during lobe formation in mouse liver development.

    Science.gov (United States)

    Weiss, Mary C; Le Garrec, Jean-Francois; Coqueran, Sabrina; Strick-Marchand, Helene; Buckingham, Margaret

    2016-04-01

    To identify cell-based decisions implicated in morphogenesis of the mammalian liver, we performed clonal analysis of hepatocytes/hepatoblasts in mouse liver development, using a knock-in allele of Hnf4a/laacZ This transgene randomly undergoes a low frequency of recombination that generates a functional lacZ gene that produces β-galactosidase in tissues in which Hnf4a is expressed. Two types of β-galactosidase-positive clones were found. Most have undergone three to eight cell divisions and result from independent events (Luria-Delbrück fluctuation test); we calculate that they arose between E8.5 and E13.5. A second class was mega-clones derived from early endoderm progenitors, generating many descendants. Some originated from multi-potential founder cells, with labeled cells in the liver, pancreas and/or intestine. A few mega-clones populate only one side of the liver, indicating hepatic cell chirality. The patterns of labeled cells indicate cohesive and often oriented growth, notably in broad radial stripes, potentially implicated in the formation of liver lobes. This retrospective clonal analysis gives novel insights into clonal origins, cell behavior of progenitors and distinct properties of endoderm cells that underlie the formation and morphogenesis of the liver.

  7. Host range restriction of vaccinia virus in Chinese hamster ovary cells: relationship to shutoff of protein synthesis.

    Science.gov (United States)

    Drillien, R; Spehner, D; Kirn, A

    1978-12-01

    Chinese hamster ovary cells were found to be nonpermissive for vaccinia virus. Although early virus-induced events occurred in these cells (RNA and polypeptide synthesis), subsequent events appeared to be prevented by a very rapid and nonselective shutoff of protein synthesis. Within less than 2 h after infection, both host and viral protein syntheses were arrested. At low multiplicities of infection, inhibition of RNA synthesis with cordycepin resulted in failure of the virus to block protein synthesis. Moreover, infection of the cells in the presence of cycloheximide prevented the immediate onset of shutoff after reversal of cycloheximide. Inactivation of virus particles by UV irradiation also impaired the capacity of the virus to inhibit protein synthesis. These results suggested that an early vaccinia virus-coded product was implicated in the shutoff of protein synthesis. Either the nonpermissive Chinese hamster ovary cells were more sensitive to this inhibition than permissive cells, or a regulatory control of the vaccinia shutoff function was defective.

  8. E1A,E1B double-restricted adenovirus enhances the cytotoxicity and antitumor activity of gemcitabine to renal cell carcinoma

    Institute of Scientific and Technical Information of China (English)

    WANG Hua; Makoto Satoh; CHEN Gui-ping; LI De-chuan; Hirofumi Hamada; Yoichi Arai

    2011-01-01

    Background Our previous studies have demonstrated potent oncolysis efficacy of the E1A,E1B double-restricted replication-competent oncolytic adenovirus AxdAdB-3 for treatment of bladder cancer. Here,we reported the feasibility and efficacy of AxdAdB-3 alone,or in combination with gemcitabine for treating renal cell carcinoma.Methods Cytopathic effects of AxdAdB-3 were evaluated in human renal cell carcinoma cell lines TOS-1,TOS-2,TOS-3,TOS-3LN,SMKT-R3,SMKT-R4 and ACHN,and in normal human renal proximal tubule epithelial cells (RPTEC).AxdAdB-3 induced down-regulation of the cell cycle was determined by flow cytometry. Combination therapies of AxdAdB-3 with gemcitabine were evaluated in vitro and in vivo on subcutaneous TOS-3LN tumors in a severe combined immunodeficiency disease (SCID) mouse model.Results AxdAdB-3 was potently cytopathic against the tested most renal cell carcinoma cell lines including TOS-2,TOS-3,TOS-3LN,SMKT-R3 and SMKT-R4,while normal human RPTEC were not destroyed. AxdAdB-3 effectively induced cell cycle S-phase entry. Combined therapy of AxdAdB-3 with gemcitabine demonstrated stronger antitumor effects in vitro and in vivo compared with either AxdAdB-3 or gemcitabine alone.Conclusion AxdAdB-3 alone,or in combination with gemcitabine may be a promising strategy against renal cell carcinoma.

  9. IL-27 receptor signalling restricts the formation of pathogenic, terminally differentiated Th1 cells during malaria infection by repressing IL-12 dependent signals.

    Directory of Open Access Journals (Sweden)

    Ana Villegas-Mendez

    Full Text Available The IL-27R, WSX-1, is required to limit IFN-γ production by effector CD4⁺ T cells in a number of different inflammatory conditions but the molecular basis of WSX-1-mediated regulation of Th1 responses in vivo during infection has not been investigated in detail. In this study we demonstrate that WSX-1 signalling suppresses the development of pathogenic, terminally differentiated (KLRG-1⁺ Th1 cells during malaria infection and establishes a restrictive threshold to constrain the emergent Th1 response. Importantly, we show that WSX-1 regulates cell-intrinsic responsiveness to IL-12 and IL-2, but the fate of the effector CD4⁺ T cell pool during malaria infection is controlled primarily through IL-12 dependent signals. Finally, we show that WSX-1 regulates Th1 cell terminal differentiation during malaria infection through IL-10 and Foxp3 independent mechanisms; the kinetics and magnitude of the Th1 response, and the degree of Th1 cell terminal differentiation, were comparable in WT, IL-10R1⁻/⁻ and IL-10⁻/⁻ mice and the numbers and phenotype of Foxp3⁺ cells were largely unaltered in WSX-1⁻/⁻ mice during infection. As expected, depletion of Foxp3⁺ cells did not enhance Th1 cell polarisation or terminal differentiation during malaria infection. Our results significantly expand our understanding of how IL-27 regulates Th1 responses in vivo during inflammatory conditions and establishes WSX-1 as a critical and non-redundant regulator of the emergent Th1 effector response during malaria infection.

  10. Conservation and diversity of influenza A H1N1 HLA-restricted T cell epitope candidates for epitope-based vaccines.

    Directory of Open Access Journals (Sweden)

    Paul Thiamjoo Tan

    Full Text Available BACKGROUND: The immune-related evolution of influenza viruses is exceedingly complex and current vaccines against influenza must be reformulated for each influenza season because of the high degree of antigenic drift among circulating influenza strains. Delay in vaccine production is a serious problem in responding to a pandemic situation, such as that of the current H1N1 strain. Immune escape is generally attributed to reduced antibody recognition of the viral hemagglutinin and neuraminidase proteins whose rate of mutation is much greater than that of the internal non-structural proteins. As a possible alternative, vaccines directed at T cell epitope domains of internal influenza proteins, that are less susceptible to antigenic variation, have been investigated. METHODOLOGY/PRINCIPAL FINDINGS: HLA transgenic mouse strains expressing HLA class I A*0201, A*2402, and B*0702, and class II DRB1*1501, DRB1*0301 and DRB1*0401 were immunized with 196 influenza H1N1 peptides that contained residues of highly conserved proteome sequences of the human H1N1, H3N2, H1N2, H5N1, and avian influenza A strains. Fifty-four (54 peptides that elicited 63 HLA-restricted peptide-specific T cell epitope responses were identified by IFN-gamma ELISpot assay. The 54 peptides were compared to the 2007-2009 human H1N1 sequences for selection of sequences in the design of a new candidate H1N1 vaccine, specifically targeted to highly-conserved HLA-restricted T cell epitopes. CONCLUSIONS/SIGNIFICANCE: Seventeen (17 T cell epitopes in PB1, PB2, and M1 were selected as vaccine targets based on sequence conservation over the past 30 years, high functional avidity, non-identity to human peptides, clustered localization, and promiscuity to multiple HLA alleles. These candidate vaccine antigen sequences may be applicable to any avian or human influenza A virus.

  11. Carbohydrate restriction and dietary cholesterol modulate the expression of HMG-CoA reductase and the LDL receptor in mononuclear cells from adult men

    Directory of Open Access Journals (Sweden)

    Volek Jeff S

    2007-11-01

    Full Text Available Abstract The liver is responsible for controlling cholesterol homeostasis in the body. HMG-CoA reductase and the LDL receptor (LDL-r are involved in this regulation and are also ubiquitously expressed in all major tissues. We have previously shown in guinea pigs that there is a correlation in gene expression of HMG-CoA reductase and the LDL-r between liver and mononuclear cells. The present study evaluated human mononuclear cells as a surrogate for hepatic expression of these genes. The purpose was to evaluate the effect of dietary carbohydrate restriction with low and high cholesterol content on HMG-CoA reductase and LDL-r mRNA expression in mononuclear cells. All subjects were counseled to consume a carbohydrate restricted diet with 10–15% energy from carbohydrate, 30–35% energy from protein and 55–60% energy from fat. Subjects were randomly assigned to either EGG (640 mg/d additional dietary cholesterol or SUB groups [equivalent amount of egg substitute (0 dietary cholesterol contributions per day] for 12 weeks. At the end of the intervention, there were no changes in plasma total or LDL cholesterol (LDL-C compared to baseline (P > 0.10 or differences in plasma total or LDL-C between groups. The mRNA abundance for HMG-CoA reductase and LDL-r were measured in mononuclear cells using real time PCR. The EGG group showed a significant decrease in HMG-CoA reductase mRNA (1.98 ± 1.26 to 1.32 ± 0.92 arbitrary units P

  12. Educating for Justice: Creating a Mission-Driven Model of Bystander Intervention to Address Sexual Violence at U.S. Catholic Colleges and Universities

    Science.gov (United States)

    Galarneau, Joy; O'Neill, Shannon

    2015-01-01

    This article presents bystander intervention education as a best-practice approach to sexual violence prevention in college settings. It draws out a connection between mission-specific resources that can be used to advance the prevention agenda, while examining how bystander intervention education can deepen community engagement in collegiate…

  13. Dietary restriction and fasting arrest B and T cell development and increase mature B and T cell numbers in bone marrow

    NARCIS (Netherlands)

    Shushimita; M.J.W. de Bruijn (Marjolein); R.W.F. de Bruin (Ron); J.N.M. IJzermans (Jan); R.W. Hendriks (Rudi); F.J.M.F. Dor (Frank)

    2014-01-01

    textabstractDietary restriction (DR) delays ageing and extends life span. Both long- and short-term DR, as well as short-term fasting provide robust protection against many "neuronal and surgery related damaging phenomena" such as Parkinson's disease and ischemia-reperfusion injury. The exact mechan

  14. Silencing of E2F3 suppresses tumor growth of Her2+ breast cancer cells by restricting mitosis.

    Science.gov (United States)

    Lee, Miyoung; Oprea-Ilies, Gabriela; Saavedra, Harold I

    2015-11-10

    The E2F transcriptional activators E2F1, E2F2 and E2F3a regulate many important cellular processes, including DNA replication, apoptosis and centrosome duplication. Previously, we demonstrated that silencing E2F1 or E2F3 suppresses centrosome amplification (CA) and chromosome instability (CIN) in Her2+ breast cancer cells without markedly altering proliferation. However, it is unknown whether and how silencing a single E2F activator, E2F3, affects malignancy of human breast cancer cells. Thus, we injected HCC1954 Her2+ breast cancer cells silenced for E2F3 into mammary fat pads of immunodeficient mice and demonstrated that loss of E2F3 retards tumor growth. Surprisingly, silencing of E2F3 led to significant reductions in mitotic indices relative to vector controls, while the percentage of cells undergoing S phase were not affected. Nek2 is a mitotic kinase commonly upregulated in breast cancers and a critical regulator of Cdk4- or E2F-mediated CA. In this report, we found that Nek2 overexpression rescued back the CA caused by silencing of shE2F3. However, the effects of Nek2 overexpression in affecting tumor growth rates of shE2F3 and shE2F3; GFP cells were inconclusive. Taken together, our results indicate that E2F3 silencing decreases mammary tumor growth by reducing percentage of cells undergoing mitosis.

  15. Expression of p13MTCP1 is restricted to mature T-cell proliferations with t(X;14) translocations.

    Science.gov (United States)

    Madani, A; Choukroun, V; Soulier, J; Cacheux, V; Claisse, J F; Valensi, F; Daliphard, S; Cazin, B; Levy, V; Leblond, V; Daniel, M T; Sigaux, F; Stern, M H

    1996-03-01

    T-cell prolymphocytic leukemia (T-PLL), a rare form of mature T-cell leukemias, and ataxia telangiectasia clonal proliferation, a related condition occurring in patients suffering from ataxia telangiectasia, have been associated to translocations involving the 14q32.1 or Xq28 regions, where are located the TCL1 and MTCP1 putative oncogenes, respectively. The MTCP1 gene is involved in the t(X;14)(q28;q11) translocation associated with these T-cell proliferations. Alternative splicing generates type A and B transcripts that potentially encode two entirely distinct proteins; type A transcripts code for a small mitochondrial protein, p8MTCP1, and type B transcripts, containing an additional open reading frame, may code for 107 amino-acid protein, p13MTCP1. The recently cloned TCL1 gene, also involved in translocations and inversions associated with T-cell proliferations, codes for a 14-kD protein that displays significant homology with p13MTCP1. We have generated rabbit antisera against this putative p13MTCP1 protein and screened for expression of p13MTCP1 normal lymphoid tissues and 33 cases of immature and mature lymphoid T-cell proliferations using a sensitive Western blot assay. We also investigated the MTCP1 locus configuration by Southern blot analysis. The p13MTCP1 protein was detected in the three T-cell proliferations with MTCP1 rearrangements because of t(X;14) translocations, but neither in normal resting and activated lymphocytes nor in the other T-cell leukemias. Our data support the hypothesis that p13MTCP1 and p14TCL1 form a new protein family that plays a key role in the pathogenesis of T-PLL and related conditions.

  16. Bystander responses to a violent incident in an immersive virtual environment.

    Science.gov (United States)

    Slater, Mel; Rovira, Aitor; Southern, Richard; Swapp, David; Zhang, Jian J; Campbell, Claire; Levine, Mark

    2013-01-01

    Under what conditions will a bystander intervene to try to stop a violent attack by one person on another? It is generally believed that the greater the size of the crowd of bystanders, the less the chance that any of them will intervene. A complementary model is that social identity is critical as an explanatory variable. For example, when the bystander shares common social identity with the victim the probability of intervention is enhanced, other things being equal. However, it is generally not possible to study such hypotheses experimentally for practical and ethical reasons. Here we show that an experiment that depicts a violent incident at life-size in immersive virtual reality lends support to the social identity explanation. 40 male supporters of Arsenal Football Club in England were recruited for a two-factor between-groups experiment: the victim was either an Arsenal supporter or not (in-group/out-group), and looked towards the participant for help or not during the confrontation. The response variables were the numbers of verbal and physical interventions by the participant during the violent argument. The number of physical interventions had a significantly greater mean in the in-group condition compared to the out-group. The more that participants perceived that the Victim was looking to them for help the greater the number of interventions in the in-group but not in the out-group. These results are supported by standard statistical analysis of variance, with more detailed findings obtained by a symbolic regression procedure based on genetic programming. Verbal interventions made during their experience, and analysis of post-experiment interview data suggest that in-group members were more prone to confrontational intervention compared to the out-group who were more prone to make statements to try to diffuse the situation.

  17. Bystander responses to a violent incident in an immersive virtual environment.

    Directory of Open Access Journals (Sweden)

    Mel Slater

    Full Text Available Under what conditions will a bystander intervene to try to stop a violent attack by one person on another? It is generally believed that the greater the size of the crowd of bystanders, the less the chance that any of them will intervene. A complementary model is that social identity is critical as an explanatory variable. For example, when the bystander shares common social identity with the victim the probability of intervention is enhanced, other things being equal. However, it is generally not possible to study such hypotheses experimentally for practical and ethical reasons. Here we show that an experiment that depicts a violent incident at life-size in immersive virtual reality lends support to the social identity explanation. 40 male supporters of Arsenal Football Club in England were recruited for a two-factor between-groups experiment: the victim was either an Arsenal supporter or not (in-group/out-group, and looked towards the participant for help or not during the confrontation. The response variables were the numbers of verbal and physical interventions by the participant during the violent argument. The number of physical interventions had a significantly greater mean in the in-group condition compared to the out-group. The more that participants perceived that the Victim was looking to them for help the greater the number of interventions in the in-group but not in the out-group. These results are supported by standard statistical analysis of variance, with more detailed findings obtained by a symbolic regression procedure based on genetic programming. Verbal interventions made during their experience, and analysis of post-experiment interview data suggest that in-group members were more prone to confrontational intervention compared to the out-group who were more prone to make statements to try to diffuse the situation.

  18. The role of cell wall-based defences in the early restriction of non-pathogenic hrp mutant bacteria in Arabidopsis.

    Science.gov (United States)

    Mitchell, Kathy; Brown, Ian; Knox, Paul; Mansfield, John

    2015-04-01

    We have investigated the cause of the restricted multiplication of hrp mutant bacteria in leaves of Arabidopsis. Our focus was on early interactions leading to differentiation between virulent wild-type and non-pathogenic hrpA mutant strains of Pseudomonas syringae pv. tomato. An initial drop in recoverable bacteria detected 0-4 h after inoculation with either strain was dependent on a functional FLS2 receptor and H2O2 accumulation in challenged leaves. Wild-type bacteria subsequently multiplied rapidly whereas the hrpA mutant was restricted within 6 h. Despite the early restriction, the hrpA mutant was still viable several days after inoculation. Analysis of intercellular washing fluids (IWFs), showed that high levels of nutrients were readily available to bacteria in the apoplast and that no diffusible inhibitors were produced in response to bacterial challenge. Histochemical and immunocytochemical methods were used to detect changes in polysaccharides (callose, two forms of cellulose, and pectin), arabinogalactan proteins (AGPs), H2O2 and peroxidase. Quantitative analysis showed very similar changes in localisation of AGPs, cellulose epitopes and callose 2 and 4 h after inoculation with either strain. However from 6 to 12 h after inoculation papillae expanded only next to the hrp mutant. In contrast to the similar patterns of secretory activity recorded from mesophyll cells, accumulation of H2O2 and peroxidase was significantly greater around the hrpA mutant within the first 4h after inoculation. A striking differential accumulation of H2O2 was also found in chloroplasts in cells next to the mutant. Ascorbate levels were lower in the IWFs recovered from sites inoculated with the hrp mutant than with wild-type bacteria. The critical response, observed at the right time and place to explain the observed differential behaviour of wild-type and hrpA mutant bacteria was the accumulation of H2O2, probably generated through Type III peroxidase activity and in

  19. Caloric restriction and the adipokine leptin alter the SDF-1 signaling axis in bone marrow and in bone marrow derived mesenchymal stem cells.

    Science.gov (United States)

    Periyasamy-Thandavan, Sudharsan; Herberg, Samuel; Arounleut, Phonepasong; Upadhyay, Sunil; Dukes, Amy; Davis, Colleen; Johnson, Maribeth; McGee-Lawrence, Meghan; Hamrick, Mark W; Isales, Carlos M; Hill, William D

    2015-07-15

    Growing evidence suggests that the chemokine stromal cell-derived factor-1 (SDF-1) is essential in regulating bone marrow (BM) derived mesenchymal stromal/stem cell (BMSC) survival, and differentiation to either a pro-osteogenic or pro-adipogenic fate. This study investigates the effects of caloric restriction (CR) and leptin on the SDF-1/CXCR4 axis in bone and BM tissues in the context of age-associated bone loss. For in vivo studies, we collected bone, BM cells and BM interstitial fluid from 12 and 20 month-old C57Bl6 mice fed ad-libitum (AL), and 20-month-old mice on long-term CR with, or without, intraperitoneal injection of leptin for 10 days (10 mg/kg). To mimic conditions of CR in vitro, 18 month murine BMSCs were treated with (1) control (Ctrl): normal proliferation medium, (2) nutrient restriction (NR): low glucose, low serum medium, or (3) NR + leptin: NR medium + 100 ng/ml leptin for 6-48 h. In BMSCs both protein and mRNA expression of SDF-1 and CXCR4 were increased by CR and CR + leptin. In contrast, the alternate SDF-1 receptor CXCR7 was decreased, suggesting a nutrient signaling mediated change in SDF-1 axis signaling in BMSCs. However, in bone SDF-1, CXCR4 and 7 gene expression increase with age and this is reversed with CR, while addition of leptin returns this to the "aged" level. Histologically bone formation was lower in the calorically restricted mice and BM adipogenesis increased, both effects were reversed with the 10 day leptin treatment. This suggests that in bone CR and leptin alter the nutrient signaling pathways in different ways to affect the local action of the osteogenic cytokine SDF-1. Studies focusing on the molecular interaction between nutrient signaling by CR, leptin and SDF-1 axis may help to address age-related musculoskeletal changes.

  20. Differential Control of BST2 Restriction and Plasmacytoid Dendritic Cell Antiviral Response by Antagonists Encoded by HIV-1 Group M and O Strains.

    Science.gov (United States)

    Bego, Mariana G; Cong, Lijun; Mack, Katharina; Kirchhoff, Frank; Cohen, Éric A

    2016-11-15

    BST2/tetherin is a type I interferon (IFN-I)-stimulated host factor that restricts the release of HIV-1 by entrapping budding virions at the cell surface. This membrane-associated protein can also engage and activate the plasmacytoid dendritic cell (pDC)-specific immunoglobulin-like transcript 7 (ILT7) inhibitory receptor to downregulate the IFN-I response by pDCs. Pandemic HIV-1 group M uses Vpu (M-Vpu) to counteract the two BST2 isoforms (long and short) that are expressed in human cells. M-Vpu efficiently downregulates surface long BST2, while it displaces short BST2 molecules away from viral assembly sites. We recently found that this attribute is used by M-Vpu to activate the BST2/ILT7-dependent negative-feedback pathway and to suppress pDC IFN-I responses during sensing of infected cells. However, whether this property is conserved in endemic HIV-1 group O, which has evolved Nef (O-Nef) to counteract specifically the long BST2 isoform, remains unknown. In the present study, we validated that O-Nefs have the capacity to downregulate surface BST2 and enhance HIV-1 particle release although less efficiently than M-Vpu. In contrast to M-Vpu, O-Nef did not efficiently enhance viral spread in T cell culture or displace short BST2 from viral assembly sites to prevent its occlusion by tethered HIV-1 particles. Consequently, O-Nef impairs the ability of BST2 to activate negative ILT7 signaling to suppress the IFN-I response by pDC-containing peripheral blood mononuclear cells (PBMCs) during sensing of infected cells. These distinctive features of BST2 counteraction by O-Nefs may in part explain the limited spread of HIV-1 group O in the human population.

  1. Debriefing bystanders of out-of-hospital cardiac arrest is valuable

    DEFF Research Database (Denmark)

    Møller, Thea Palsgaard; Hansen, Carolina Malta; Fjordholt, Martin

    2014-01-01

    , positively influencing the ability to cope with the emotional reactions and the cognitive perception of own performance and motivates improvement of CPR skills. Importantly, it increases confidence to provide CPR in the future. Implementation of telephone debriefing to bystanders at Emergency Medical...... the phenomenological approach. RESULTS: Six themes emerged from analysis of debriefing audio files: (1) identification of OHCA; (2) emotional and perceptual experience with OHCA; (3) collaboration with healthcare professionals; (4) patients outcome; (5) coping with the experience and (6) general reflections. When...

  2. Bringing in the target audience in bystander social marketing materials for communities: suggestions for practitioners.

    Science.gov (United States)

    Potter, Sharyn J; Stapleton, Jane G

    2011-06-01

    The Know Your Power™ social marketing campaign images model active bystander behaviors that target audience members can use in situations where sexual and relationship violence and stalking are occurring, have occurred, or have the potential to occur. In this practitioner note, we describe strategies that we have used to engage target audience members in the development of the social marketing campaign that we hope can be used by practitioners. We give examples from the development and evaluation of the Know Your Power(TM) social marketing campaign that used focus group and other types of feedback from the target audience to inform the direction of the campaign.

  3. Serratia fonticola, pathogen or bystander? A case series and review of the literature

    Directory of Open Access Journals (Sweden)

    Abdullah Aljorayid

    2016-01-01

    We reviewed 17 other patients with clinical cultures positive for S. fonticola. Of these, 11 isolates were from the genitourinary system, most often as part of a polymicrobial culture. The majority of the other organisms recovered were recognized pathogens from the Enterobacteriaceae family. The cases suggest that when recovered in conjunction with other organisms, S. fonticola does not lead to enhanced virulence or worse clinical outcomes and may be a bystander. When detected alone, which is a rare occurrence, S. fonticola may function as a human pathogen.

  4. Interactions of opsonized immune complexes with whole blood cells: binding to erythrocytes restricts complex uptake by leucocyte populations

    DEFF Research Database (Denmark)

    Nielsen, C H; Svehag, S E; Marquart, H V;

    1994-01-01

    The binding of opsonized, fluorescein-labelled bovine serum albumin (BSA)/rabbit anti-BSA complexes (IC) to washed human whole blood cells and isolated leucocytes in the presence of autologous serum was investigated by flow cytometry. In the presence of erythrocytes (E), the IC-binding to granulo......The binding of opsonized, fluorescein-labelled bovine serum albumin (BSA)/rabbit anti-BSA complexes (IC) to washed human whole blood cells and isolated leucocytes in the presence of autologous serum was investigated by flow cytometry. In the presence of erythrocytes (E), the IC...

  5. TNF-Mediated Restriction of Arginase 1 Expression in Myeloid Cells Triggers Type 2 NO Synthase Activity at the Site of Infection.

    Science.gov (United States)

    Schleicher, Ulrike; Paduch, Katrin; Debus, Andrea; Obermeyer, Stephanie; König, Till; Kling, Jessica C; Ribechini, Eliana; Dudziak, Diana; Mougiakakos, Dimitrios; Murray, Peter J; Ostuni, Renato; Körner, Heinrich; Bogdan, Christian

    2016-05-01

    Neutralization or deletion of tumor necrosis factor (TNF) causes loss of control of intracellular pathogens in mice and humans, but the underlying mechanisms are incompletely understood. Here, we found that TNF antagonized alternative activation of macrophages and dendritic cells by IL-4. TNF inhibited IL-4-induced arginase 1 (Arg1) expression by decreasing histone acetylation, without affecting STAT6 phosphorylation and nuclear translocation. In Leishmania major-infected C57BL/6 wild-type mice, type 2 nitric oxide (NO) synthase (NOS2) was detected in inflammatory dendritic cells or macrophages, some of which co-expressed Arg1. In TNF-deficient mice, Arg1 was hyperexpressed, causing an impaired production of NO in situ. A similar phenotype was seen in L. major-infected BALB/c mice. Arg1 deletion in hematopoietic cells protected these mice from an otherwise lethal disease, although their disease-mediating T cell response (Th2, Treg) was maintained. Thus, deletion or TNF-mediated restriction of Arg1 unleashes the production of NO by NOS2, which is critical for pathogen control.

  6. TNF-Mediated Restriction of Arginase 1 Expression in Myeloid Cells Triggers Type 2 NO Synthase Activity at the Site of Infection

    Directory of Open Access Journals (Sweden)

    Ulrike Schleicher

    2016-05-01

    Full Text Available Neutralization or deletion of tumor necrosis factor (TNF causes loss of control of intracellular pathogens in mice and humans, but the underlying mechanisms are incompletely understood. Here, we found that TNF antagonized alternative activation of macrophages and dendritic cells by IL-4. TNF inhibited IL-4-induced arginase 1 (Arg1 expression by decreasing histone acetylation, without affecting STAT6 phosphorylation and nuclear translocation. In Leishmania major-infected C57BL/6 wild-type mice, type 2 nitric oxide (NO synthase (NOS2 was detected in inflammatory dendritic cells or macrophages, some of which co-expressed Arg1. In TNF-deficient mice, Arg1 was hyperexpressed, causing an impaired production of NO in situ. A similar phenotype was seen in L. major-infected BALB/c mice. Arg1 deletion in hematopoietic cells protected these mice from an otherwise lethal disease, although their disease-mediating T cell response (Th2, Treg was maintained. Thus, deletion or TNF-mediated restriction of Arg1 unleashes the production of NO by NOS2, which is critical for pathogen control.

  7. A HLA-A2 restricted human CTL line recognizes a novel tumor cell expressed p53 epitope

    DEFF Research Database (Denmark)

    Würtzen, Peter A; Claesson, Mogens H

    2002-01-01

    , the CTL line, which expressed relatively low affinity for the HLA-A2/peptide complex, was able to kill 3 different HLA-A2(+) p53 mutated tumor cell lines. The present and our previous observations expand the number of p53-derived peptides suitable for vaccination protocols for cancer patients with p53......A p53 peptide-specific CTL line was generated through stimulation with autologous monocyte-derived dendritic cells (DC) pulsed with wild-type HLA-A2 binding p53 derived peptides. A p53 peptide-specific CD8(+) CTL line was established from a healthy HLA-A2 positive donor. The CTL line...... was characterized with respect to specificity, affinity and killing of cell lines derived from p53 mutated spontaneous tumors. The CTL line demonstrated lysis of p53(139-147) pulsed target cells and cold target inhibition experiments as well as antibody blocking confirmed that the killing was epitope-specific, HLA...

  8. Preformed purified peptide/major histocompatibility class I complexes are potent stimulators of class I-restricted T cell hybridomas

    DEFF Research Database (Denmark)

    Stryhn, A; Pedersen, L O; Ortiz-Navarrete, V;

    1994-01-01

    and quantitated. Latex particles were subsequently coated with known amounts of preformed complexes and used to stimulate the T cell hybridomas. Stimulation was specific, i.e. only the appropriate peptide/class I combination were stimulatory, and quite sensitive, i.e. as little as 300 complexes per bead could...

  9. Effects of food restriction on glucose tolerance, insulin secretion, and islet-cell proliferation in pregnant rats

    NARCIS (Netherlands)

    Nieuwenhuizen, AG; Schuiling, GA; Seijsener, AFJ; Moes, H; Koiter, TR

    1999-01-01

    Pregnancy is associated with increased glucose-stimulated insulin secretion and increased pancreatic is in-cell proliferation. In the present study it was investigated whether increased food intake, as occurs during pregnancy, Is Involved in the regulation of these phenomena. From Day 0 of pregnancy

  10. Selective Targeting and Restrictive Damage for Nonspecific Cells by Pulsed Laser-Activated Hyaluronan-Gold Nanoparticles.

    Science.gov (United States)

    Rau, Lih-Rou; Tsao, Shu-Wei; Liaw, Jiunn-Woei; Tsai, Shiao-Wen

    2016-08-08

    Herein, we describe an approach that immobilizes low-molecular-weight hyaluronic acid (low-MW HA) on the surface of gold nanoparticles (GNPs), which can serve as a cellular probe and photodamage media, to evaluate the selectivity and efficiency of HA-based GNPs (HGNPs) as a mediator of laser-induced photothermal cell damage. In addition, it is known that solid tumors contain a higher content of low-MW HA than normal tissues. Thus, we used low-MW HA rather than high-MW HA used in other studies. In the present study, we conjugated low-MW HA, which is a linear polysaccharide with a disaccharide repeat unit, to prevent a reduction of the ligand-receptor binding efficiency in contrast to the conjugation of protein or peptides, which have unique three-dimensional structures. Three cell lines-MDA-MB-435 S (with CD44), MDA-MB-453 and NIH/3T3 (both are without CD44)-were investigated in the study, and qualitative observations were conducted by dark-field microscopy and laser scanning confocal microscopy (LSCM). In addition, quantitative measurements calculated using inductively coupled plasma emissions were taken for comparison. Our results showed that within the same treatment time, the uptake dosage of HGNPs by the MDA-MB-435 S cells was higher than that by the MDA-MB-453 and NIH 3T3 cells. Meanwhile, HGNPs uptake by the untreated MDA-MB-435 S cells was higher than that of MDA-MB-435 S cells with CD44 blocked by antibodies or silencing CD44 expression. This result implies that receptor-mediated endocytosis can enhance the cellular uptake of HGNPs. In addition, when exposed to a low-power pulsed laser, the former cell morphologies showed a more laser-induced giant plasma membrane vesicles (GPMV) than the latter morphologies. Therefore, this study utilized the specific photothermal property of HA-modified GNPs with laser-induced blebs to create a possible new method for medical applications.

  11. B-cell responses to pregnancy-restricted and -unrestricted Plasmodium falciparum erythrocyte membrane protein 1 antigens in Ghanaian women naturally exposed to malaria parasites

    DEFF Research Database (Denmark)

    Ampomah, Paulina; Stevenson, Liz; Ofori, Michael F;

    2014-01-01

    Protective immunity to Plasmodium falciparum malaria acquired after natural exposure is largely antibody mediated. IgG-specific P. falciparum EMP1 (PfEMP1) proteins on the infected erythrocyte surface are particularly important. The transient antibody responses and the slowly acquired protective...... immunity probably reflect the clonal antigenic variation and allelic polymorphism of PfEMP1. However, it is likely that other immune-evasive mechanisms are also involved, such as interference with formation and maintenance of immunological memory. We measured PfEMP1-specific antibody levels by enzyme......-linked immunosorbent assay (ELISA) and memory B-cell frequencies by enzyme-linked immunosorbent spot (ELISPOT) assay in a cohort of P. falciparum-exposed nonpregnant Ghanaian women. The antigens used were a VAR2CSA-type PfEMP1 (IT4VAR04) with expression restricted to parasites infecting the placenta, as well as two...

  12. Acute response of peripheral CCr5 chemoreceptor and NK cells in individuals submitted to a single session of low-intensity strength exercise with blood flow restriction.

    Science.gov (United States)

    Dorneles, Gilson Pires; Colato, Alana Schraiber; Galvão, Simone Lunelli; Ramis, Thiago Rozales; Ribeiro, Jerri Luiz; Romão, Pedro Roosevelt; Peres, Alessandra

    2016-07-01

    The purpose of this study was to compare the peripheral expression of natural killers and CCR5 in a session of low-intensity strength training with vascular occlusion and in high-intensity training. Young males were randomized into session groups of a high-intensity strength training (HI) and a session group of low-intensity strength training with vascular occlusion (LI-BFR). The exercise session consisted in knee extension and bicep curl in 80% 1RM (HI) and 30% 1RM (LI-BFR) with equalized volumes. Blood collection was made before, immediately after and 24 h after each training session. Immunophenotyping was carried out through CD195+ (CCR5) e CD3-CD16+CD56+ (NK) in peripheral blood and analysed by flow cytometry and presented in frequency (%). Peripheral frequency of NK cells showed no significant difference in LI-BFR group in time effect, while a gradual reduction of NK cells was identified in HI group in before-24 h postexercise and after-24 h postexercise comparison. However, significant differences have been found in relative change of NK cells immediately after exercise between sessions. In addition, HI and LI-BFR groups showed a significant reduction in the cells expressed CCR5 during 24 h postsession compared to the postsession, but CCR5 also differed when comparing before-24 h after session in the HI group. No differences were observed amongst the groups. LIO induced CCR5 response similar to the HI session, while the NK cells remained in similar frequency during the studied moments in LI-BFR, but not in HI group, suggesting that local hypoxia created by the blood flow restriction was able to prevent a change in the frequency of peripheral cells and a possible immunosuppression.

  13. act up controls actin polymerization to alter cell shape and restrict Hedgehog signaling in the Drosophila eye disc.

    Science.gov (United States)

    Benlali, A; Draskovic, I; Hazelett, D J; Treisman, J E

    2000-04-28

    Cells in the morphogenetic furrow of the Drosophila eye disc undergo a striking shape change immediately prior to their neuronal differentiation. We have isolated mutations in a novel gene, act up (acu), that is required for this shape change. acu encodes a homolog of yeast cyclase-associated protein, which sequesters monomeric actin; we show that acu is required to prevent actin filament polymerization in the eye disc. In contrast, profilin promotes actin filament polymerization, acting epistatically to acu. However, both acu and profilin are required to prevent premature Hedgehog-induced photoreceptor differentiation ahead of the morphogenetic furrow. These findings suggest that dynamic changes in actin filaments alter cell shape to control the movement of signals that coordinate a wave of differentiation.

  14. IL-27 in human secondary lymphoid organs attracts myeloid dendritic cells and impairs HLA class I-restricted antigen presentation.

    Science.gov (United States)

    Morandi, Fabio; Di Carlo, Emma; Ferrone, Soldano; Petretto, Andrea; Pistoia, Vito; Airoldi, Irma

    2014-03-15

    Different cytokines play crucial roles in inflammation and in polarizing immune responses, including IL-27 that exerts pro- and anti-inflammatory functions. Although the activity of IL-27 is well characterized in murine immune cells, only limited information is available regarding the natural cellular sources of IL-27 in humans and its effects on human immune cells. Dendritic cells (DCs) are the most potent professional APCs that in the immature state are positioned throughout peripheral tissues by acting as sentinels, sensing the presence of Ags. Activated DCs migrate into the lymph nodes and direct Ag-specific T cell responses, thus acting as key players in both adaptive and innate immunity. In this study we asked whether IL-27 is produced by human secondary lymphoid organs and what is its functional role on human DCs. To our knowledge, we provide the first evidence that 1) in lymph nodes, macrophages are the major source for IL-27; 2) immature and mature human DCs express functional IL-27R; 3) IL-27 exerts immunosuppressive activity by crippling the Ag processing machinery in immature DCs under steady-state conditions and after pulsing with a viral Ag; and 4) IL-27 is chemotactic for human DCs. Our findings highlight novel mechanisms underlying the immunosuppressive activity of IL-27, suggesting that this cytokine may function as a homeostatic cytokine in secondary lymphoid organs by limiting duration and/or intensity of ongoing adaptive immune responses. The results presented in this study pave the way to future studies aimed at investigating whether dysregulation of IL-27 expression and function may be involved in pathogenesis of autoimmune disease and cancer.

  15. Restricted VH/VL usage and limited mutations in gluten-specific IgA of coeliac disease lesion plasma cells.

    Science.gov (United States)

    Steinsbø, Øyvind; Henry Dunand, Carole J; Huang, Min; Mesin, Luka; Salgado-Ferrer, Marlene; Lundin, Knut E A; Jahnsen, Jørgen; Wilson, Patrick C; Sollid, Ludvig M

    2014-06-09

    Coeliac disease (CD), an enteropathy caused by cereal gluten ingestion, is characterized by CD4(+) T cells recognizing deamidated gluten and by antibodies reactive to gluten or the self-antigen transglutaminase 2 (TG2). TG2-specific immunoglobulin A (IgA) of plasma cells (PCs) from CD lesions have limited somatic hypermutation (SHM). Here we report that gluten-specific IgA of lesion-resident PCs share this feature. Monoclonal antibodies were expression cloned from single PCs of patients either isolated from cultures with reactivity to complex deamidated gluten antigen or by sorting with gluten peptide tetramers. Typically, the antibodies bind gluten peptides related to T-cell epitopes and many have higher reactivity to deamidated peptides. There is restricted VH and VL combination and usage among the antibodies. Limited SHM suggests that a common factor governs the mutation level in PCs producing TG2- and gluten-specific IgA. The antibodies have potential use for diagnosis of CD and for detection of gluten.

  16. 3' UTR-dependent, miR-92-mediated restriction of Tis21 expression maintains asymmetric neural stem cell division to ensure proper neocortex size.

    Science.gov (United States)

    Fei, Ji-Feng; Haffner, Christiane; Huttner, Wieland B

    2014-04-24

    Mammalian neocortex size primarily reflects the number and mode of divisions of neural stem and progenitor cells. Cortical stem cells (apical progenitors) switching from symmetric divisions, which expand their population, to asymmetric divisions, which generate downstream neuronal progenitors (basal progenitors), start expressing Tis21, a so-called antiproliferative/prodifferentiative gene. Tis21 encodes a small (17.5 kDa), functionally poorly characterized protein and a relatively large (2 kb), highly conserved 3' UTR. Here, we show that mice lacking the Tis21 3' UTR develop a microcephalic neocortex with fewer neurons, notably in the upper layers. This reflects a progressive decrease in basal progenitors, which in turn is due to a fraction of apical progenitors prematurely switching from asymmetric self-renewing to symmetric self-consuming divisions. This switch is caused by the markedly increased Tis21 protein level resulting from lack of microRNA-, notably miR-92-, dependent restriction of Tis21 expression. Our data show that a premature onset of consumptive neural stem cell divisions can lead to microcephaly.

  17. Electronic Cigarettes and Indoor Air Quality: A Simple Approach to Modeling Potential Bystander Exposures to Nicotine

    Directory of Open Access Journals (Sweden)

    Stéphane Colard

    2014-12-01

    Full Text Available There has been rapid growth in the use of electronic cigarettes (“vaping” in Europe, North America and elsewhere. With such increased prevalence, there is currently a debate on whether the aerosol exhaled following the use of e-cigarettes has implications for the quality of air breathed by bystanders. Conducting chemical analysis of the indoor environment can be costly and resource intensive, limiting the number of studies which can be conducted. However, this can be modelled reasonably accurately based on empirical emissions data and using some basic assumptions. Here, we present a simplified model, based on physical principles, which considers aerosol propagation, dilution and extraction to determine the potential contribution of a single puff from an e-cigarette to indoor air. From this, it was then possible to simulate the cumulative effect of vaping over time. The model was applied to a virtual, but plausible, scenario considering an e-cigarette user and a non-user working in the same office space. The model was also used to reproduce published experimental studies and showed good agreement with the published values of indoor air nicotine concentration. With some additional refinements, such an approach may be a cost-effective and rapid way of assessing the potential exposure of bystanders to exhaled e-cigarette aerosol constituents.

  18. Electronic cigarettes and indoor air quality: a simple approach to modeling potential bystander exposures to nicotine.

    Science.gov (United States)

    Colard, Stéphane; O'Connell, Grant; Verron, Thomas; Cahours, Xavier; Pritchard, John D

    2014-12-24

    There has been rapid growth in the use of electronic cigarettes ("vaping") in Europe, North America and elsewhere. With such increased prevalence, there is currently a debate on whether the aerosol exhaled following the use of e-cigarettes has implications for the quality of air breathed by bystanders. Conducting chemical analysis of the indoor environment can be costly and resource intensive, limiting the number of studies which can be conducted. However, this can be modelled reasonably accurately based on empirical emissions data and using some basic assumptions. Here, we present a simplified model, based on physical principles, which considers aerosol propagation, dilution and extraction to determine the potential contribution of a single puff from an e-cigarette to indoor air. From this, it was then possible to simulate the cumulative effect of vaping over time. The model was applied to a virtual, but plausible, scenario considering an e-cigarette user and a non-user working in the same office space. The model was also used to reproduce published experimental studies and showed good agreement with the published values of indoor air nicotine concentration. With some additional refinements, such an approach may be a cost-effective and rapid way of assessing the potential exposure of bystanders to exhaled e-cigarette aerosol constituents.

  19. The role of gender, values, and culture in adolescent bystanders' strategies.

    Science.gov (United States)

    Tamm, Anni; Tulviste, Tiia

    2015-02-01

    We examined the relationship between adolescent bystanders' strategies for intervening in the bullying-like situation and their gender, values, and cultural origin. The sample consisted of 682 Estonian and Russian-Estonian adolescents (M age = 13.02 years). They were shown a video of a bullying-like situation with a non-intervening adult bystander and asked to describe what they would do if they, instead of the adult, witnessed that situation. Only 10% said that they would not intervene. Girls were more likely than boys to suggest multiple actions. Adolescents who valued conformity were less likely to propose using physical aggression. Doing nothing was less likely suggested by those who placed more importance on conformity and less on power. Estonian adolescents were more likely than their Russian-Estonian peers to suggest finding out what is going on, and less likely to say that they would do nothing. The findings suggest that although most adolescents express willingness to help the victim, they might not actually know how to intervene.

  20. Ombud’s Corner: Bystanders, you can have a role too

    CERN Multimedia

    Sudeshna Datta-Cockerill

    2015-01-01

    If you find yourself repeatedly witnessing a situation of inter personal conflict or tension between other colleagues, you have a choice: you can either turn a blind eye to it or you can try to help. In the latter case, you may wish to get another perspective or some guidance before taking steps.   Stefan, Paul and Lucas work together on a challenging project. Over time, Lucas has started to notice Paul’s verbally aggressive behaviour towards Stefan: he frequently criticises him in public, cuts him short at meetings when he is trying to make his point and is known to make derogatory remarks about him behind his back. Stefan does not seem to react but the tension between them is evident and Lucas feels increasingly uncomfortable in their company. It is never easy to know whether or not to intervene in these delicate situations, and the ‘bystander effect’ - where people do nothing - tends to prevail in most workplace cultures. Bystanders hesitate to act because th...

  1. Adipogenic placenta-derived mesenchymal stem cells are not lineage restricted by withdrawing extrinsic factors: developing a novel visual angle in stem cell biology.

    Science.gov (United States)

    Hu, C; Cao, H; Pan, X; Li, J; He, J; Pan, Q; Xin, J; Yu, X; Li, J; Wang, Y; Zhu, D; Li, L

    2016-03-17

    Current evidence implies that differentiated bone marrow mesenchymal stem cells (BMMSCs) can act as progenitor cells and transdifferentiate across lineage boundaries. However, whether this unrestricted lineage has specificities depending on the stem cell type is unknown. Placental-derived mesenchymal stem cells (PDMSCs), an easily accessible and less invasive source, are extremely useful materials in current stem cell therapies. No studies have comprehensively analyzed the transition in morphology, surface antigens, metabolism and multilineage potency of differentiated PDMSCs after their dedifferentiation. In this study, we showed that after withdrawing extrinsic factors, adipogenic PDMSCs reverted to a primitive cell population and retained stem cell characteristics. The mitochondrial network during differentiation and dedifferentiation may serve as a marker of absent or acquired pluripotency in various stem cell models. The new population proliferated faster than unmanipulated PDMSCs and could be differentiated into adipocytes, osteocytes and hepatocytes. The cell adhesion molecules (CAMs) signaling pathway and extracellular matrix (ECM) components modulate cell behavior and enable the cells to proliferate or differentiate during the differentiation, dedifferentiation and redifferentiation processes in our study. These observations indicate that the dedifferentiated PDMSCs are distinguishable from the original PDMSCs and may serve as a novel source in stem cell biology and cell-based therapeutic strategies. Furthermore, whether PDMSCs differentiated into other lineages can be dedifferentiated to a primitive cell population needs to be investigated.

  2. Adipogenic placenta-derived mesenchymal stem cells are not lineage restricted by withdrawing extrinsic factors: developing a novel visual angle in stem cell biology

    Science.gov (United States)

    Hu, C; Cao, H; Pan, X; Li, J; He, J; Pan, Q; Xin, J; Yu, X; Li, J; Wang, Y; Zhu, D; Li, L

    2016-01-01

    Current evidence implies that differentiated bone marrow mesenchymal stem cells (BMMSCs) can act as progenitor cells and transdifferentiate across lineage boundaries. However, whether this unrestricted lineage has specificities depending on the stem cell type is unknown. Placental-derived mesenchymal stem cells (PDMSCs), an easily accessible and less invasive source, are extremely useful materials in current stem cell therapies. No studies have comprehensively analyzed the transition in morphology, surface antigens, metabolism and multilineage potency of differentiated PDMSCs after their dedifferentiation. In this study, we showed that after withdrawing extrinsic factors, adipogenic PDMSCs reverted to a primitive cell population and retained stem cell characteristics. The mitochondrial network during differentiation and dedifferentiation may serve as a marker of absent or acquired pluripotency in various stem cell models. The new population proliferated faster than unmanipulated PDMSCs and could be differentiated into adipocytes, osteocytes and hepatocytes. The cell adhesion molecules (CAMs) signaling pathway and extracellular matrix (ECM) components modulate cell behavior and enable the cells to proliferate or differentiate during the differentiation, dedifferentiation and redifferentiation processes in our study. These observations indicate that the dedifferentiated PDMSCs are distinguishable from the original PDMSCs and may serve as a novel source in stem cell biology and cell-based therapeutic strategies. Furthermore, whether PDMSCs differentiated into other lineages can be dedifferentiated to a primitive cell population needs to be investigated. PMID:26986509

  3. Functional and Structural Characterization of a Novel HLA-DRB1*04:01-Restricted α-enolase T Cell Epitope in Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Christina Gerstner

    2016-11-01

    Full Text Available Antibodies to citrullinated proteins, common in Rheumatoid Arthritis (RA patients, are strongly associated to a specific set of HLA-DR alleles including HLA-DRB1*04:01, *04:04 and *01:01. Here, we first demonstrate that autoantibody levels towards the dominant citrullinated B cell epitope from α-enolase are significantly elevated in HLA-DRB1*04:01-positive RA patients. Furthermore, we identified α-enolase-derived T cell epitopes and demonstrated that native and citrullinated versions of several peptides bind with different affinities to HLA-DRB1*04:01, *04:04 and *01:01. The citrulline residues in the eight identified peptides are distributed throughout the entire length of the presented epitopes and more specifically, localized at peptide positions p-2, p2, p4, p6, p7, p10 and p11. Importantly, in contrast to its native version peptide 26 (TSKGLFRAAVPSGAS, the HLA-DRB1*04:01-restricted citrullinated peptide Cit26 (TSKGLFCitAAVPSGAS elicited significant functional T cell responses in primary cells from RA patients. Comparative analysis of the crystal structures of HLA-DRB1*04:01 in complex with peptide 26 or Cit26 demonstrated that the post-translational modification did not alter the conformation of the peptide. And since citrullination is the only structural difference between the two complexes this indicates that the neo-antigen Cit26 is recognized by T cells with high specificity to the citrulline residue.

  4. Identification and immunogenicity of two new HLA-A*0201-restricted CD8+ T-cell epitopes on dengue NS1 protein.

    Science.gov (United States)

    Tian, Jiang; Zeng, Gucheng; Pang, Xianwu; Liang, Mifang; Zhou, Junmei; Fang, Danyun; Liu, Yan; Li, Dexin; Jiang, Lifang

    2012-04-01

    Immunopathogenesis of dengue virus (DEN) infection remains poorly studied. Identification and characterization of human CD8(+) T-cell epitopes on DEN are necessary for a better understanding of the immunopathogenesis of dengue infection and would facilitate the development of immunotherapy and vaccines to protect from dengue infection. Here, we identified two new HLA-A*0201-restricted CD8(+) T-cell epitopes, DEN-4 NS1(990)(-998) and DEN-4 NS1(997)(-1005) that are conserved in three or four major DEN serotypes, respectively. Unexpectedly, we found that immunization of HLA-A*0201 transgenic mice with DEN-4 NS1(990)(-998) or DEN-4 NS1(997)(-1005) epitope peptide induced de novo synthesis of tumor necrosis factor (TNF)-α and IFN-γ, two important pro-inflammatory molecules that are hard to be detected directly without in vitro antigenic re-stimulation. Importantly, we demonstrated that CD8(+) T cells specifically activated by DEN-4 NS1(990)(-998) or DEN-4 NS1(997)(-1005) epitope peptide induced de novo synthesis of perforin. Furthermore, we observed that DEN-4 NS1(990)(-998) or DEN-4 NS1(997)(-1005)-specific CD8(+) T cells capable of producing large amounts of perforin, TNF-α and IFN-γ preferentially displayed CD27(+)CD45RA(-), but not CD27(-)CD45RA(+), phenotypes. This study, therefore, suggested the importance of synergistic effects of pro-inflammatory cytokines and cytotoxic molecules which were produced by dengue-specific CD8(+) T cells in immunopathogenesis or anti-dengue immunity during dengue infection.

  5. The archipelago ubiquitin ligase subunit acts in target tissue to restrict tracheal terminal cell branching and hypoxic-induced gene expression.

    Directory of Open Access Journals (Sweden)

    Nathan T Mortimer

    Full Text Available The Drosophila melanogaster gene archipelago (ago encodes the F-box/WD-repeat protein substrate specificity factor for an SCF (Skp/Cullin/F-box-type polyubiquitin ligase that inhibits tumor-like growth by targeting proteins for degradation by the proteasome. The Ago protein is expressed widely in the fly embryo and larva and promotes degradation of pro-proliferative proteins in mitotically active cells. However the requirement for Ago in post-mitotic developmental processes remains largely unexplored. Here we show that Ago is an antagonist of the physiologic response to low oxygen (hypoxia. Reducing Ago activity in larval muscle cells elicits enhanced branching of nearby tracheal terminal cells in normoxia. This tracheogenic phenotype shows a genetic dependence on sima, which encodes the HIF-1α subunit of the hypoxia-inducible transcription factor dHIF and its target the FGF ligand branchless (bnl, and is enhanced by depletion of the Drosophila Von Hippel Lindau (dVHL factor, which is a subunit of an oxygen-dependent ubiquitin ligase that degrades Sima/HIF-1α protein in metazoan cells. Genetic reduction of ago results in constitutive expression of some hypoxia-inducible genes in normoxia, increases the sensitivity of others to mild hypoxic stimulus, and enhances the ability of adult flies to recover from hypoxic stupor. As a molecular correlate to these genetic data, we find that Ago physically associates with Sima and restricts Sima levels in vivo. Collectively, these findings identify Ago as a required element of a circuit that suppresses the tracheogenic activity of larval muscle cells by antagonizing the Sima-mediated transcriptional response to hypoxia.

  6. Caloric restriction restores the chronological life span of the Goa1 null mutant of Candida albicans in spite of high cell levels of ROS.

    Science.gov (United States)

    Chen, Hui; Calderone, Richard; Sun, Nuo; Wang, Yun; Li, Dongmei

    2012-12-01

    The Candida albicans Goa1p is required for mitochondrial functions. In a strain lacking GOA1 (GOA31), respiration, mitochondrial membrane potential, complex I (CI) activity of the electron transport chain, and ATP synthesis are significantly decreased. A shortened chronological life span (CLS) of GOA31 occurs in 2% glucose that is associated with an increase in cell reactive oxidant species (ROS) and apoptosis. We now show that caloric restriction (CR) in media containing 0.5% glucose instead of 2% glucose-SC extends the CLS to the level of parental and gene-reconstituted strains. Paradoxically, ROS levels in GOA31 far exceed those of control strains in 0.5% glucose and, as a consequence, increased lipid peroxidation occurs even though CLS is restored. Microarray analysis was used to characterize transcriptional changes during CR in GOA31. We found that CR shifts cells of all strains to a non-glucose carbon metabolism (β-oxidation). Our model of ROS formation in GOA31 follows the paradigm that the generation of oxygen radicals from β-oxidation of cell lipids via FADH(2) (CII) and NADH (CI) creates an unfavorable cellular FADH(2)/NADH ratio that causes a transient overload in CII activity resulting in excess free cell radicals. In GOA31 the CI and peroxisomal dysfunctions increase the levels of ROS compared to control strains. Recovery from high levels of ROS may be associated with an increase in iron and sugar transporters, as well as an anti-stress response that includes the SOD1 and GPX1. Thus, CR creates a favorable growth environment, but cells of GOA31 must overcome a high but transient ROS production.

  7. The Emergence of New Paradigms in Student-University Relations: From In Loco Parentis to Bystander to Facilitator.

    Science.gov (United States)

    Bickel, Robert D.; Lake, Peter F.

    1997-01-01

    University liability is in transition; its role changing from a parental/custodial "in loco parentis" model (and then a bystander role) to a new model of facilitator. The university enjoys a position of authority and respect, while exercising control more subtly than in the mid-1990s. At the same time, universities may be unable to claim the same…

  8. Perceptions of pesticides exposure risks by operators, workers, residents and bystanders in Greece, Italy and the UK

    NARCIS (Netherlands)

    Remoundou, K.; Brennan, M.; Sacchettini, G.; Panzone, L.; Butler-Ellis, M.C.; Capri, E.; Charistou, A.; Chaideftou, E.; Gerritsen-Ebben, M.G.; Machera, K.; Spanoghe, P.; Glass, R.; Marchis, A.; Doanngoc, K.; Hart, A.; Frewer, L.J.

    2015-01-01

    The EU Directive on the sustainable use of pesticides (EU128/2009/EC) requires European Member States to develop training activities targeting occupational exposure to pesticides, and communication material aimed at residents and bystanders. Risk perceptions, knowledge and attitudes associated with

  9. Pseudo-postpacing interval of diastolic potential after entrainment pacing of remote bystander pathway in reentrant ventricular tachycardia.

    Science.gov (United States)

    Kaneko, Yoshiaki; Nakajima, Tadashi; Irie, Tadanobu; Igawa, Osamu; Iijima, Takafumi; Ota, Masaki; Tamura, Mio; Iizuka, Takashi; Tamura, Shuntaro; Saito, Akihiro; Kurabayashi, Masahiko

    2014-09-01

    After entrainment pacing, the postpacing interval of a diastolic potential may be misinterpreted if the distal tip of the ablation catheter captures a remote bystander pathway adjacent to the critical isthmus of a complex reentrant circuit in a structurally diseased heart. We discuss this possible pitfall of entrainment mapping of reentrant ventricular tachycardia, observed after a healed myocardial infarction.

  10. Pseudo-postpacing interval of diastolic potential after entrainment pacing of remote bystander pathway in reentrant ventricular tachycardia

    OpenAIRE

    Kaneko, Yoshiaki; Nakajima, Tadashi; Irie, Tadanobu; Igawa, Osamu; Iijima, Takafumi; Ota, Masaki; Tamura, Mio; Iizuka, Takashi; Tamura, Shuntaro; Saito, Akihiro; Kurabayashi, Masahiko

    2013-01-01

    After entrainment pacing, the postpacing interval of a diastolic potential may be misinterpreted if the distal tip of the ablation catheter captures a remote bystander pathway adjacent to the critical isthmus of a complex reentrant circuit in a structurally diseased heart. We discuss this possible pitfall of entrainment mapping of reentrant ventricular tachycardia, observed after a healed myocardial infarction.

  11. Bystanders' Reactions to Bullying: A Cross-Cultural Analysis of Personal Correlates among Italian and Singaporean Students

    Science.gov (United States)

    Pozzoli, Tiziana; Ang, Rebecca P.; Gini, Gianluca

    2012-01-01

    This study examined the role of attitudes against bullying and perceived peer pressure for intervention in explaining defending the victim and passive bystanding behavior in bullying. Participants were 1031 school-age children from two culturally diverse settings, namely Italy and Singapore, which are similar on several dimensions (e.g., quality…

  12. Isolation of human CD4/CD8 double-positive, graft-versus-host disease-protective, minor histocompatibility antigen-specific regulatory T cells and of a novel HLA-DR7-restricted HY-specific CD4 clone.

    Science.gov (United States)

    Eljaafari, Assia; Yuruker, Ozel; Ferrand, Christophe; Farre, Annie; Addey, Caroline; Tartelin, Marie-Laure; Thomas, Xavier; Tiberghien, Pierre; Simpson, Elizabeth; Rigal, Dominique; Scott, Diane

    2013-01-01

    Minor histocompatibility (H) Ags are classically described as self-peptides derived from intracellular proteins that are expressed at the cell surface by MHC class I and class II molecules and that induce T cell alloresponses. We have isolated three different T cell populations from a skin biopsy of a patient suffering from acute graft-versus-host disease following sex-mismatched HLA-identical bone marrow transplantation. The first population was: 1) CD4(+)/CD8(+) double-positive; 2) specific for an HLA class I-restricted autosomal Ag; 3) expressed a Tr1 profile with high levels of IL-10, but low IL-2 and IFN-γ; and 4) exerted regulatory function in the presence of recipient APCs. The second was CD8 positive, specific for an HLA class I-restricted autosomally encoded minor H Ag, but was only weakly cytotoxic. The third was CD4 single positive, specific for an HLA-DR7-restricted HY epitope and exerted both proliferative and cytotoxic functions. Identification of the peptide recognized by these latter cells revealed a new human HY epitope, TGKIINFIKFDTGNL, encoded by RPS4Y and restricted by HLA-DR7. In this paper, we show human CD4/CD8 double-positive, acute graft-versus-host disease-protective, minor H Ag-specific regulatory T cells and identify a novel HLA-DR7/ HY T cell epitope, encoded by RPS4Y, a potential new therapeutic target.

  13. ATR-p53 restricts homologous recombination in response to replicative stress but does not limit DNA interstrand crosslink repair in lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Bianca M Sirbu

    Full Text Available Homologous recombination (HR is required for the restart of collapsed DNA replication forks and error-free repair of DNA double-strand breaks (DSB. However, unscheduled or hyperactive HR may lead to genomic instability and promote cancer development. The cellular factors that restrict HR processes in mammalian cells are only beginning to be elucidated. The tumor suppressor p53 has been implicated in the suppression of HR though it has remained unclear why p53, as the guardian of the genome, would impair an error-free repair process. Here, we show for the first time that p53 downregulates foci formation of the RAD51 recombinase in response to replicative stress in H1299 lung cancer cells in a manner that is independent of its role as a transcription factor. We find that this downregulation of HR is not only completely dependent on the binding site of p53 with replication protein A but also the ATR/ATM serine 15 phosphorylation site. Genetic analysis suggests that ATR but not ATM kinase modulates p53's function in HR. The suppression of HR by p53 can be bypassed under experimental conditions that cause DSB either directly or indirectly, in line with p53's role as a guardian of the genome. As a result, transactivation-inactive p53 does not compromise the resistance of H1299 cells to the interstrand crosslinking agent mitomycin C. Altogether, our data support a model in which p53 plays an anti-recombinogenic role in the ATR-dependent mammalian replication checkpoint but does not impair a cell's ability to use HR for the removal of DSB induced by cytotoxic agents.

  14. Circumsporozoite Protein-Specific Kd-Restricted CD8+ T Cells Mediate Protective Antimalaria Immunity in Sporozoite-Immunized MHC-I-Kd Transgenic Mice

    Directory of Open Access Journals (Sweden)

    Jing Huang

    2014-01-01

    Full Text Available Although the roles of CD8+ T cells and a major preerythrocytic antigen, the circumsporozoite (CS protein, in contributing protective antimalaria immunity induced by radiation-attenuated sporozoites, have been shown by a number of studies, the extent to which these players contribute to antimalaria immunity is still unknown. To address this question, we have generated C57BL/6 (B6 transgenic (Tg mice, expressing Kd molecules under the MHC-I promoter, called MHC-I-Kd-Tg mice. In this study, we first determined that a single immunizing dose of IrPySpz induced a significant level of antimalaria protective immunity in MHC-I-Kd-Tg mice but not in B6 mice. Then, by depleting various T-cell subsets in vivo, we determined that CD8+ T cells are the main mediator of the protective immunity induced by IrPySpz. Furthermore, when we immunized (MHC-I-Kd-Tg × CS-Tg F1 mice with IrPySpz after crossing MHC-I-Kd-Tg mice with PyCS-transgenic mice (CS-Tg, which are unable to mount PyCS-specific immunity, we found that IrPySpz immunization failed to induce protective antimalaria immunity in (MHC-I-Kd-Tg × CS-Tg F1 mice, thus indicating the absence of PyCS antigen-dependent immunity in these mice. These results indicate that protective antimalaria immunity induced by IrPySpz in MHC-I-Kd-Tg mice is mediated by CS protein-specific, Kd-restricted CD8+ T cells.

  15. Overcoming CD4 Th1 Cell Fate Restrictions to Sustain Antiviral CD8 T Cells and Control Persistent Virus Infection

    Directory of Open Access Journals (Sweden)

    Laura M. Snell

    2016-09-01

    Full Text Available Viral persistence specifically inhibits CD4 Th1 responses and promotes Tfh immunity, but the mechanisms that suppress Th1 cells and the disease consequences of their loss are unclear. Here, we demonstrate that the loss of CD4 Th1 cells specifically leads to progressive CD8 T cell decline and dysfunction during viral persistence. Therapeutically reconstituting CD4 Th1 cells restored CD4 T cell polyfunctionality, enhanced antiviral CD8 T cell numbers and function, and enabled viral control. Mechanistically, combined interaction of PD-L1 and IL-10 by suppressive dendritic cell subsets inhibited new CD4 Th1 cells in both acute and persistent virus infection, demonstrating an unrecognized suppressive function for PD-L1 in virus infection. Thus, the loss of CD4 Th1 cells is a key event leading to progressive CD8 T cell demise during viral persistence with important implications for restoring antiviral CD8 T cell immunity to control persistent viral infection.

  16. Overcoming CD4 Th1 Cell Fate Restrictions to Sustain Antiviral CD8 T Cells and Control Persistent Virus Infection.

    Science.gov (United States)

    Snell, Laura M; Osokine, Ivan; Yamada, Douglas H; De la Fuente, Justin Rafael; Elsaesser, Heidi J; Brooks, David G

    2016-09-20

    Viral persistence specifically inhibits CD4 Th1 responses and promotes Tfh immunity, but the mechanisms that suppress Th1 cells and the disease consequences of their loss are unclear. Here, we demonstrate that the loss of CD4 Th1 cells specifically leads to progressive CD8 T cell decline and dysfunction during viral persistence. Therapeutically reconstituting CD4 Th1 cells restored CD4 T cell polyfunctionality, enhanced antiviral CD8 T cell numbers and function, and enabled viral control. Mechanistically, combined interaction of PD-L1 and IL-10 by suppressive dendritic cell subsets inhibited new CD4 Th1 cells in both acute and persistent virus infection, demonstrating an unrecognized suppressive function for PD-L1 in virus infection. Thus, the loss of CD4 Th1 cells is a key event leading to progressive CD8 T cell demise during viral persistence with important implications for restoring antiviral CD8 T cell immunity to control persistent viral infection.

  17. Cell death-inducing DFF45-like effector C is reduced by caloric restriction and regulates adipocyte lipid metabolism.

    Science.gov (United States)

    Magnusson, Björn; Gummesson, Anders; Glad, Camilla A M; Goedecke, Julia H; Jernås, Margareta; Lystig, Theodore C; Carlsson, Björn; Fagerberg, Björn; Carlsson, Lena M S; Svensson, Per-Arne

    2008-09-01

    Members of the cell death-inducing DFF45-like effector (CIDE) gene family have been shown to regulate lipid metabolism. In this article, we report that the third member of the human CIDE family, CIDEC, is down-regulated in response to a reduced caloric intake. The down-regulation was demonstrated by microarray and real-time polymerase chain reaction analysis of subcutaneous adipose tissue in 2 independent studies on obese patients undergoing treatment with a very low calorie diet. By analysis of CIDEC expression in 65 human tissues, we conclude that human CIDEC is predominantly expressed in subcutaneous adipocytes. Together, these observations led us to investigate the effect of decreased CIDEC expression in cultured 3T3-L1 adipocytes. Small interfering RNA-mediated knockdown of CIDEC resulted in an increased basal release of nonesterified fatty acids, decreased responsiveness to adrenergic stimulation of lipolysis, and increased oxidation of endogenous fatty acids. Thus, we suggest that CIDEC is a regulator of adipocyte lipid metabolism and may be important for the adipocyte to adapt to changes in energy availability.

  18. Claudin-5 is restricted to the tight junction region of uterine epithelial cells in the uterus of pregnant/gravid squamate reptiles.

    Science.gov (United States)

    Biazik, Joanna M; Thompson, Michael B; Murphy, Christopher R

    2008-05-01

    Claudin-5, a tight junctional protein associated with ion and size selectivity, has been found in the uterus of skinks. This study has generated critical information about the molecular assembly of the tight junction at various stages of the reproductive cycle in the skink uterus. Recent studies looking at tight junctional proteins found occludin expression in the tight junction region of uterine epithelial cells in the skink uterus; however, occludin did not disclose any further information about the ions and size of ions permeating across the paracellular pathway. A approximately 22-kDa claudin-5 band was detected in the uterus of the skinks present in this study and immunohistochemistry revealed that claudin-5 redistributes to the tight junction region of the lateral plasma membrane of uterine epithelial cells in late stage pregnancy/gravidity. This finding indicates that the tight junction becomes more assembled to precisely regulate ion and solute permeation in late stage pregnancy/gravidity. Claudin-5 with its functional role as a molecular sieve due to the formation of ion and size selective pores suggests that permeation of ions smaller than 0.8 kDa are restricted when claudin-5 is redistributed to the tight junction region of the later plasma membrane. This report is the first description of the molecular mechanisms that may be involved in regulating nutrient provision in the reptilian uterus.

  19. EFFECTS OF RESTRICTED BASILAR PAPILLAR LESIONS AND HAIR CELL REGENERATION ON AUDITORY FOREBRAIN FREQUENCY ORGANIZATION IN ADULT EUROPEAN STARLINGS

    Science.gov (United States)

    Irvine, Dexter R. F.; Brown, Mel; Kamke, Marc R.; Rubel, Edwin W

    2009-01-01

    The frequency organization of neurons in the forebrain Field L complex (FLC) of adult starlings was investigated to determine the effects of hair cell (HC) destruction in the basal portion of the basilar papilla (BP) and of subsequent HC regeneration. Conventional microelectrode mapping techniques were used in normal starlings and in lesioned starlings either 2 days or 6–10 weeks after aminoglycoside treatment. Histological examination of the BP and recordings of auditory brainstem evoked responses confirmed massive loss of HCs in the basal portion of the BP and hearing losses at frequencies above 2 kHz in starlings tested 2 days after aminoglycoside treatment. In these birds, all neurons in the region of the FLC in which CFs normally increase from 2 to 6 kHz had characteristic frequency (CF) in the range 2–4 kHz. The significantly elevated thresholds of responses in this region of altered tonotopic organization indicated that they were the residue of pre-lesion responses and did not reflect central nervous system plasticity. In the long-term recovery birds, there was histological evidence of substantial HC regeneration. The tonotopic organization of the high frequency region of the FLC did not differ from that in normal starlings, but the mean threshold at CF in this frequency range was intermediate between the values in the normal and lesioned short-recovery groups. The recovery of normal tonotopicity indicates considerable stability of the topography of neuronal connections in the avian auditory system, but the residual loss of sensitivity suggests deficiencies in high-frequency HC function. PMID:19474314

  20. Effects of restricted basilar papillar lesions and hair cell regeneration on auditory forebrain frequency organization in adult European starlings.

    Science.gov (United States)

    Irvine, Dexter R F; Brown, Mel; Kamke, Marc R; Rubel, Edwin W

    2009-05-27

    The frequency organization of neurons in the forebrain Field L complex (FLC) of adult starlings was investigated to determine the effects of hair cell (HC) destruction in the basal portion of the basilar papilla (BP) and of subsequent HC regeneration. Conventional microelectrode mapping techniques were used in normal starlings and in lesioned starlings either 2 d or 6-10 weeks after aminoglycoside treatment. Histological examination of the BP and recordings of auditory brainstem evoked responses confirmed massive loss of HCs in the basal portion of the BP and hearing losses at frequencies >2 kHz in starlings tested 2 d after aminoglycoside treatment. In these birds, all neurons in the region of the FLC in which characteristic frequencies (CFs) normally increase from 2 to 6 kHz had CF in the range of 2-4 kHz. The significantly elevated thresholds of responses in this region of altered tonotopic organization indicated that they were the residue of prelesion responses and did not reflect CNS plasticity. In the long-term recovery birds, there was histological evidence of substantial HC regeneration. The tonotopic organization of the high-frequency region of the FLC did not differ from that in normal starlings, but the mean threshold at CF in this frequency range was intermediate between the values in the normal and lesioned short-recovery groups. The recovery of normal tonotopicity indicates considerable stability of the topography of neuronal connections in the avian auditory system, but the residual loss of sensitivity suggests deficiencies in high-frequency HC function.

  1. Expression of Interferon γ by Decidual Cells and Natural Killer Cells at the Human Implantation Site: Implications for Preeclampsia, Spontaneous Abortion, and Intrauterine Growth Restriction.

    Science.gov (United States)

    Chen, Chie-Pein; Piao, Longzhu; Chen, Xilin; Yu, Jianhua; Masch, Rachel; Schatz, Frederick; Lockwood, Charles J; Huang, S Joseph

    2015-11-01

    Human first-trimester decidual cells (FTDCs) chemoattract CXCR3-expressing circulating CD56(bright)CD16(-) natural killer (NK) cells, which increase uteroplacental blood flow by remodeling spiral arteries and arterioles. This recruitment reflects elevated FTDC expression of NK cell-recruiting induced protein 10 and interferon (IFN)-inducible T-cell-α chemoattractant produced in response to the synergistic effects of tumor necrosis factor α (TNF-α) and IFN-γ stimulation. Decidual macrophages express TNF-α, whereas the cellular origin of IFN-γ is unclear. Therefore, this study aims to identify the cell source(s) of IFN-γ in human first trimester decidua. Immunostaining of decidual sections revealed that both FTDCs and decidual NK (dNK) cells express IFN-γ. Although individual dNK cells express higher IFN-γ levels, the more numerous FTDCs account for greater proportion of total IFN-γ immunostaining. Freshly isolated FTDCs express greater IFN-γ staining than dNK cells as measured by flow cytometry, whereas incubation of dNK cells with documented NK cell activators significantly increases IFN-γ above FTDC levels. Confluent FTDCs intrinsically produce, but paradoxically respond to, exogenous IFN-γ.

  2. A HEV-restricted sulfotransferase is expressed in rheumatoid arthritis synovium and is induced by lymphotoxin-α/β and TNF-α in cultured endothelial cells

    Directory of Open Access Journals (Sweden)

    Palao Guillermo

    2005-03-01

    Full Text Available Abstract Background The recruitment of lymphocytes to secondary lymphoid organs relies on interactions of circulating cells with high endothelial venules (HEV. HEV are exclusive to these organs under physiological conditions, but they can develop in chronically-inflamed tissues. The interaction of L-selectin on lymphocytes with sulfated glycoprotein ligands on HEV results in lymphocyte rolling, which represents the initial step in lymphocyte homing. HEV expression of GlcNAc6ST-2 (also known as HEC-GlcNAc6ST, GST-3, LSST or CHST4, an HEV-restricted sulfotransferase, is essential for the elaboration of L-selectin functional ligands as well as a critical epitope recognized by MECA-79 mAb. Results We examined the expression of GlcNAc6ST-2 in relationship to the MECA-79 epitope in rheumatoid arthritis (RA synovial vessels. Expression of GlcNAc6ST-2 was specific to RA synovial tissues as compared to osteoarthritis synovial tissues and localized to endothelial cells of HEV-like vessels and small flat-walled vessels. Double MECA-79 and GlcNAc6ST-2 staining showed colocalization of the MECA-79 epitope and GlcNAc6ST-2. We further found that both TNF-α and lymphotoxin-αβ induced GlcNAc6ST-2 mRNA and protein in cultured human umbilical vein endothelial cells. Conclusion These observations demonstrate that GlcNAc6ST-2 is induced in RA vessels and provide potential cytokine pathways for its induction. GlcNAc6ST-2 is a novel marker of activated vessels within RA ectopic lymphoid aggregates. This enzyme represents a potential therapeutic target for RA.

  3. Circulating preproinsulin signal peptide-specific CD8 T cells restricted by the susceptibility molecule HLA-A24 are expanded at onset of type 1 diabetes and kill β-cells.

    Science.gov (United States)

    Kronenberg, Deborah; Knight, Robin R; Estorninho, Megan; Ellis, Richard J; Kester, Michel G; de Ru, Arnoud; Eichmann, Martin; Huang, Guo C; Powrie, Jake; Dayan, Colin M; Skowera, Ania; van Veelen, Peter A; Peakman, Mark

    2012-07-01

    Type 1 diabetes results from T cell-mediated β-cell destruction. The HLA-A*24 class I gene confers significant risk of disease and early onset. We tested the hypothesis that HLA-A24 molecules on islet cells present preproinsulin (PPI) peptide epitopes to CD8 cytotoxic T cells (CTLs). Surrogate β-cell lines secreting proinsulin and expressing HLA-A24 were generated and their peptide ligandome examined by mass spectrometry to discover naturally processed and HLA-A24-presented PPI epitopes. A novel PPI epitope was identified and used to generate HLA-A24 tetramers and examine the frequency of PPI-specific T cells in new-onset HLA-A*24(+) patients and control subjects. We identified a novel naturally processed and HLA-A24-presented PPI signal peptide epitope (PPI(3-11); LWMRLLPLL). HLA-A24 tetramer analysis reveals a significant expansion of PPI(3-11)-specific CD8 T cells in the blood of HLA-A*24(+) recent-onset patients compared with HLA-matched control subjects. Moreover, a patient-derived PPI(3-11)-specific CD8 T-cell clone shows a proinflammatory phenotype and kills surrogate β-cells and human HLA-A*24(+) islet cells in vitro. These results indicate that the type 1 diabetes susceptibility molecule HLA-A24 presents a naturally processed PPI signal peptide epitope. PPI-specific, HLA-A24-restricted CD8 T cells are expanded in patients with recent-onset disease. Human islet cells process and present PPI(3-11), rendering themselves targets for CTL-mediated killing.

  4. A highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirus B19 infection in HLA-A*2402-positive individuals

    DEFF Research Database (Denmark)

    Kasprowicz, V; Jeffery, K; Broliden, K;

    2006-01-01

    Six of seven HLA-A*2402-positive individuals with acute parvovirus B19 infections made vigorous CD8-positive cytotoxic T-cell (CTL) responses to the viral epitope FYTPLADQF. All responders showed highly focused T-cell receptor (TCR) usage, using almost exclusively BV5.1. The BV5.1 TCR dominated...

  5. Preliminary exploration of HLA-A 1101-restricted human cytomegalovirus glycoprotein B-specific CD8⁺ T cells in allogeneic stem-cell transplant recipients.

    Science.gov (United States)

    Liu, Anbing; Hu, Jianhua; Wu, Wei; Huang, Yaping; Liang, Hanying; Wang, Huiqi; Yang, Rong; Fan, Jun

    2014-08-08

    T-cell responses directed against human cytomegalovirus (HCMV) glycoprotein B (gB) contribute to protective immunity against HCMV infection in both animal models and humans. However, the gB-specific human CD8(+) T cell responses remain poorly understood. gB antigen-specific CD8(+) T cells were stained with seven major histocompatibility complex (MHC)-peptide pentamers in 16 human leukocyte antigen (HLA)-A 1101-positive, HCMV-seropositive patients following hematopoietic stem cell transplantation (HSCT). Of these seven pentamers, the most frequent CD8(+) T-cell responses were directed against the gB332-340 peptide. These gB332-340-specific CD8(+) T cells were strongly associated with the presence of plasma HCMV immunoglobulin M in all HSCT recipients and exhibited a probable causal relationship with the level of pp65 antigenemia. Together, these data suggest a role for gB332-340-specific CD8(+) T cells in HCMV reactivation after HSCT. Furthermore, the pentamer assay may be valuable in detecting antigen-specific CD8(+) T cells.

  6. Ectopic overexpression of engrailed-2 in cerebellar Purkinje cells causes restricted cell loss and retarded external germinal layer development at lobule junctions.

    Science.gov (United States)

    Baader, S L; Sanlioglu, S; Berrebi, A S; Parker-Thornburg, J; Oberdick, J

    1998-03-01

    Members of the En and Wnt gene families seem to play a key role in the early specification of the brain territory that gives rise to the cerebellum, the midhindbrain junction. To analyze the possible continuous role of the En and Wnt signaling pathway in later cerebellar patterning and function, we expressed En-2 ectopically in Purkinje cells during late embryonic and postnatal cerebellar development. As a result of this expression, the cerebellum is greatly reduced in size, and Purkinje cell numbers throughout the cerebellum are reduced by more than one-third relative to normal animals. Detailed analysis of both adult and developing cerebella reveals a pattern of selectivity to the loss of Purkinje cells and other cerebellar neurons. This is observed as a general loss of prominence of cerebellar fissures that is highlighted by a total loss of sublobular fissures. In contrast, mediolateral patterning is generally only subtly affected. That En-2 overexpression selectively affects Purkinje cells in the transition zone between lobules is evidenced by direct observation of selective Purkinje cell loss in certain fissures and by the observation that growth and migration of the external germinal layer (EGL) is selectively retarded in the deep fissures during early postnatal development. Thus, in addition to demonstrating the critical role of Purkinje cells in the generation and migration of granule cells, the heterogeneous distribution of cellular effects induced by ectopic En expression suggests a relatively late morphogenetic role for this and other segment polarity proteins, mainly oriented at lobule junctions.

  7. The role of individual and collective moral disengagement in peer aggression and bystanding: a multilevel analysis.

    Science.gov (United States)

    Gini, Gianluca; Pozzoli, Tiziana; Bussey, Kay

    2015-04-01

    This study investigates the relationships between individual and collective moral disengagement and aggression-related behaviors (peer aggression, defending, and passive bystanding) among 918 adolescents (55.8% boys; M age = 14.1 years, SD = 1.1). Hierarchical linear modeling showed that, at the individual level, aggressive behavior was significantly explained by both individual moral disengagement and student perceived collective moral disengagement, which was also positively associated with defending. Student perceived collective moral disengagement moderated the link between individual moral disengagement and peer aggression. At the class level, classroom collective moral disengagement explained between-class variability in all the three aggression-related behaviors. These results extend previous research by demonstrating the role of collective moral disengagement at the individual and the class levels and have potential implications for interventions.

  8. An immunodominant HLA-A*1101-restricted CD8+ T-cell response targeting hepatitis B surface antigen in chronic hepatitis B patients.

    Science.gov (United States)

    Chen, Xiaoling; Wang, Wenbo; Wang, Shufeng; Meng, Gang; Zhang, Mengjun; Ni, Bing; Wu, Yuzhang; Wang, Li

    2013-12-01

    Hepatitis B virus (HBV) infection is a worldwide public health problem. HBV-specific CD8(+) CTLs are vital for viral clearance. Identification of immunodominant CTL epitopes from HBV-associated antigens is necessary for therapeutic vaccine development. We showed that the HLA-A*1101 allele is one of the most common alleles in both healthy individuals and chronic hepatitis B (CHB) patients in the Chongqing area, China. However, less than 10% of epitopes of HBV-associated antigens have been identified in an HLA-A*1101 context. Here, we describe an immunodominant CD8(+) T-cell response targeting a hepatitis B surface antigen determinant (HBs(295-304)) restricted by HLA-A*1101 in both healthy individuals and CHB patients. Moreover, HBs(295-304) is more immunogenic for CTL induction than a known naturally HLA-A*1101-processed epitope from hepatitis B core antigen (HBc(88-96)). Therefore, the newly identified epitope, HBs(295-304), will benefit the development of immunotherapeutic approaches for HBV infection.

  9. Oncogenic pathways impinging on the G2-restriction point

    NARCIS (Netherlands)

    Foijer, F; Simonis, M; van Vliet, M; Wessels, L; Kerkhoven, R; Sorger, P K; Te Riele, H

    2008-01-01

    In the absence of mitogenic stimuli, cells normally arrest in G(1/0), because they fail to pass the G1-restriction point. However, abrogation of the G1-restriction point (by loss of the retinoblastoma gene family) reveals a second-restriction point that arrests cells in G2. Serum-starvation-induced

  10. The broad-spectrum antiviral compound ST-669 restricts chlamydial inclusion development and bacterial growth and localizes to host cell lipid droplets within treated cells.

    Science.gov (United States)

    Sandoz, Kelsi M; Valiant, William G; Eriksen, Steven G; Hruby, Dennis E; Allen, Robert D; Rockey, Daniel D

    2014-07-01

    Novel broad-spectrum antimicrobials are a critical component of a strategy for combating antibiotic-resistant pathogens. In this study, we explored the activity of the broad-spectrum antiviral compound ST-669 for activity against different intracellular bacteria and began a characterization of its mechanism of antimicrobial action. ST-669 inhibits the growth of three different species of chlamydia and the intracellular bacterium Coxiella burnetii in Vero and HeLa cells but not in McCoy (murine) cells. The antichlamydial and anti-C. burnetii activity spectrum was consistent with those observed for tested viruses, suggesting a common mechanism of action. Cycloheximide treatment in the presence of ST-669 abrogated the inhibitory effect, demonstrating that eukaryotic protein synthesis is required for tested activity. Immunofluorescence microscopy demonstrated that different chlamydiae grow atypically in the presence of ST-669, in a manner that suggests the compound affects inclusion formation and organization. Microscopic analysis of cells treated with a fluorescent derivative of ST-669 demonstrated that the compound localized to host cell lipid droplets but not to other organelles or the host cytosol. These results demonstrate that ST-669 affects intracellular growth in a host-cell-dependent manner and interrupts proper development of chlamydial inclusions, possibly through a lipid droplet-dependent process.

  11. Blame Conformity: Innocent Bystanders Can Be Blamed for a Crime as a Result of Misinformation from a Young, but Not Elderly, Adult Co-Witness.

    Science.gov (United States)

    Thorley, Craig

    2015-01-01

    This study examined whether or not exposing an eyewitness to a co-witness statement that incorrectly blames an innocent bystander for a crime can increase the likelihood of the eyewitness subsequently blaming the innocent bystander for the crime. It also examined whether or not the perceived age of the co-witness influences this effect. Participant eyewitnesses first watched a video of a crime featuring a perpetrator and an innocent bystander. They then read one of six bogus co-witness statements about the crime. All were presented as having been written by a female co-witness and they differed in terms of her age (young adult or elderly) and who she blamed for the crime (the perpetrator, the innocent bystander, or nobody). One week later the participants were asked who committed the crime. When the young adult co-witness had blamed the innocent bystander just over 40% of participants subsequently did the same. Few participants (less than 8%) in the other conditions subsequently blamed the innocent bystander. The elderly co-witness was also rated as less credible, less competent, and less accurate than the younger co-witness suggesting eyewitnesses were less likely to be influenced by her incorrect statement as they perceived her to be a less reliable source of information. The applied implications of these findings are discussed.

  12. Restrictions and Proportionality

    DEFF Research Database (Denmark)

    Werlauff, Erik

    2009-01-01

    The article discusses three central aspects of the freedoms under European Community law, namely 1) the prohibition against restrictions as an important extension of the prohibition against discrimination, 2) a prohibition against exit restrictions which is just as important as the prohibition...... against host country restrictions, but which is often not recognised to the same extent by national law, and 3) the importance of also identifying and recognising an exit restriction, so that it is possible to achieve the required test of appropriateness and proportionality in relation to the rule...

  13. A Variable-Energy Soft X-Ray Microprobe to Investigate Mechanisms of the Radiation-Induced Bystander Effect.

    Energy Technology Data Exchange (ETDEWEB)

    Folkard, Melvyn; Vojnovic, Borivoj; Schettino, Giuseppe; Atkinson, Kirk; Prise, Kevin, M.; Michael, Barry, D.

    2007-01-23

    The Gray Cancer Institute has pioneered the use of X ray focussing techniques to develop systems for micro irradiating individual cells and sub cellular targets in vitro. Cellular micro irradiation is now recognised as a highly versatile technique for understanding how ionising radiation interacts with living cells and tissues. The strength of the technique lies in its ability to deliver precise doses of radiation to selected individual cells (or sub cellular targets). The application of this technique in the field of radiation biology continues to be of great interest for investigating a number of phenomena currently of concern to the radiobiological community. One important phenomenon is the so called ‘bystander effect’ where it is observed that unirradiated cells can also respond to signals transmitted by irradiated neighbours. Clearly, the ability of a microbeam to irradiate just a single cell or selected cells within a population is well suited to studying this effect. Our prototype ‘tabletop’ X-ray microprobe was optimised for focusing 278 eV C-K X rays and has been used successfully for a number of years. However, we have sought to develop a new variable energy soft X-ray microprobe capable of delivering focused CK (0.28 keV), Al-K (1.48 keV) and notably, Ti-K (4.5 keV) X rays. Ti-K X rays are capable of penetrating several cell layers and are therefore much better suited to studies involving tissues and multi cellular layers. In our new design, X-rays are generated by the focussed electron bombardment of a material whose characteristic-K radiation is required. The source is mounted on a 1.5 x 1.0 metre optical table. Electrons are generated by a custom built gun, designed to operate up to 15 kV. The electrons are focused using a permanent neodymium iron boron magnet assembly. Focusing is achieved by adjusting the accelerating voltage and by fine tuning the target position via a vacuum position feedthrough. To analyze the electron beam properties, a

  14. Perceptions of pesticides exposure risks by operators, workers, residents and bystanders in Greece, Italy and the UK

    Energy Technology Data Exchange (ETDEWEB)

    Remoundou, K.; Brennan, M. [Food and Society Group, Centre for Rural Economy, School of Agriculture, Food and Rural Development, Newcastle University, Newcastle Upon Tyne NE19 1AA (United Kingdom); Sacchettini, G. [Opera Research Centre, Università Cattolica del Sacro Cuore di Piacenza, 29100 Piacenza (Italy); Panzone, L. [Food and Society Group, Centre for Rural Economy, School of Agriculture, Food and Rural Development, Newcastle University, Newcastle Upon Tyne NE19 1AA (United Kingdom); Butler-Ellis, M.C. [Silsoe Spray Applications Unit, NIAB, Building 42, Wrest Park, Silsoe, Bedford MK45 4HP (United Kingdom); Capri, E. [Opera Research Centre, Università Cattolica del Sacro Cuore di Piacenza, 29100 Piacenza (Italy); Charistou, A.; Chaideftou, E. [Benaki Phytopathological Institute, 8 Stefanou Delta Street, Kifissia, Athens 14561 (Greece); Gerritsen-Ebben, M.G. [TNO Innovation for Life, Utrechtseweg 48, 3704 HE Zeist (Netherlands); Machera, K. [Benaki Phytopathological Institute, 8 Stefanou Delta Street, Kifissia, Athens 14561 (Greece); Spanoghe, P. [Department of Crop Protection, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Glass, R. [Food and Environmental Research Agency, Sand Hutton, York Y0411LZ (United Kingdom); Marchis, A. [Opera Research Centre, Università Cattolica del Sacro Cuore di Piacenza, 29100 Piacenza (Italy); Doanngoc, K. [Department of Crop Protection, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Hart, A. [Food and Environmental Research Agency, Sand Hutton, York Y0411LZ (United Kingdom); Frewer, L.J., E-mail: Lynn.Frewer@newcastle.ac.uk [Food and Society Group, Centre for Rural Economy, School of Agriculture, Food and Rural Development, Newcastle University, Newcastle Upon Tyne NE19 1AA (United Kingdom)

    2015-02-01

    The EU Directive on the sustainable use of pesticides (EU128/2009/EC) requires European Member States to develop training activities targeting occupational exposure to pesticides, and communication material aimed at residents and bystanders. Risk perceptions, knowledge and attitudes associated with passive and occupational exposure to pesticide potentially influence the extent to which different stakeholders adopt self-protective behaviour. A methodology for assessing the link between attitudes, adoption of self-protective behaviours and exposure was developed and tested. A survey was implemented in the Greece, Italy and the UK, and targeted stakeholders associated with pesticide exposure linked to orchards, greenhouse crops and arable crops respectively. The results indicated that the adoption of protective measures is low for residents and bystanders, with the exception of residents in Greece, when compared to operators and workers, who tend to follow recommended safety practices. A regression analysis was used to examine the factors affecting the probability of adopting protective measures as well the as the level of exposure in the case of operators and workers where data are available. The results indicate that the likelihood of engaging in self-protective behaviour is not significantly affected by perceptions of own health being affected by pesticides for residents and bystanders. However, operators who perceive that their heath has been negatively affected by the use of pesticides are found to be more likely to adopt self-protective behaviours. Gender and country differences, in perceptions, attitudes and self-protection are also observed. Recommendations for improved communication, in particular for vulnerable groups, are provided. - Highlights: • Perceptions of risks associated with pesticide exposure were assessed • Surveys were conducted in Greece, Italy and the UK targeting vulnerable stakeholders • Perceptions of risk were associated with

  15. Radiation-induced bystander effects: Are they good bad or both?; Les nouvelles orientations en radiobiologie et radiopathologie

    Energy Technology Data Exchange (ETDEWEB)

    Le Guen, B.; Lallemand, J. [Electricite de France (EDF), 75 - Paris (France); Averbeck, D. [Institut Curie, 75 - Paris (France); Chetioui, A. [Paris-6 Univ., 75 (France); Gardes-Albert, M. [Paris-5 Univ., 75 (France); Mothersill, C. [Mc Master Univ., Hamilton (Canada); Gourmelon, P.; Benderitter, M. [Institut de Radioprotection et de Surete Nucleaire, 92 - Clamart (France); Chevillard, S.; Martin, M. [CEA Fontenay-aux-Roses, Dir. des sciences du vivant, 92 (France); Verrelle, P. [Centre Jean-Perrin, 63 - Clermont-Ferrand (France)

    2004-07-01

    The different contributions are as follow: the current events on the cellular responses to irradiation ( part one and two); From physico-chemistry to radiobiology: new knowledge (part one and two); Radiation-induced bystander effects: are they good bad or both; recognition of the multi visceral failure in the acute irradiation syndrome; integrated approach of the tissue carcinogenesis: differential effect sane tissue-tumoral tissue; differential diagnosis of thyroid cancers by the transcriptoma analysis. (N.C.)

  16. SAMHD1 restricts HIV-1 infection in dendritic cells (DCs by dNTP depletion, but its expression in DCs and primary CD4+ T-lymphocytes cannot be upregulated by interferons

    Directory of Open Access Journals (Sweden)

    St Gelais Corine

    2012-12-01

    Full Text Available Abstract Background SAMHD1 is an HIV-1 restriction factor in non-dividing monocytes, dendritic cells (DCs, macrophages, and resting CD4+ T-cells. Acting as a deoxynucleoside triphosphate (dNTP triphosphohydrolase, SAMHD1 hydrolyzes dNTPs and restricts HIV-1 infection in macrophages and resting CD4+ T-cells by decreasing the intracellular dNTP pool. However, the intracellular dNTP pool in DCs and its regulation by SAMHD1 remain unclear. SAMHD1 has been reported as a type I interferon (IFN-inducible protein, but whether type I IFNs upregulate SAMHD1 expression in primary DCs and CD4+ T-lymphocytes is unknown. Results Here, we report that SAMHD1 significantly blocked single-cycle and replication-competent HIV-1 infection of DCs by decreasing the intracellular dNTP pool and thereby limiting the accumulation of HIV-1 late reverse transcription products. Type I IFN treatment did not upregulate endogenous SAMHD1 expression in primary DCs or CD4+ T-lymphocytes, but did in HEK 293T and HeLa cell lines. When SAMHD1 was over-expressed in these two cell lines to achieve higher levels than that in DCs, no HIV-1 restriction was observed despite partially reducing the intracellular dNTP pool. Conclusions Our results suggest that SAMHD1-mediated reduction of the intracellular dNTP pool in DCs is a common mechanism of HIV-1 restriction in myeloid cells. Endogenous expression of SAMHD1 in primary DCs or CD4+ T-lymphocytes is not upregulated by type I IFNs.

  17. Workplace mobbing and bystanders' helping behaviour towards victims: the role of gender, perceived responsibility and anticipated stigma by association.

    Science.gov (United States)

    Mulder, Roelie; Pouwelse, Mieneke; Lodewijkx, Hein; Bolman, Catherine

    2014-08-01

    We examined victims' perceived responsibility and bystanders' anticipated risk of being victimized themselves when others associate them with the victim (stigma by association, SBA) as possible antecedents of bystanders' helping behaviour towards a victim of workplace mobbing, and explored the effects of gender. Guided by the attribution model of social conduct (Weiner, 2006), a 2 × 2 vignette experiment was conducted. Participants were Dutch regional government employees (N = 161). Path analyses generally supported the hypotheses, but showed different results for women and men. In the strong (Vs. weak) responsibility condition, women reported less sympathy and more anger and men only more anger, which resulted in lower helping intention. Additionally, for men the results showed an unexpected direct positive effect of responsibility on helping intention. Furthermore, in the strong SBA condition, women and men reported more fear and men, unexpectedly, more anger. Consequently, helping intention decreased. The findings on gender are discussed in the context of social role theory, gender and emotion. Our findings suggest that to prevent and tackle mobbing, organizations and professionals should be aware of the attributional and emotional processes and gender differences in bystanders' helping behaviour.

  18. Induction of CD8 T-cell responses restricted to multiple HLA class I alleles in a cancer patient by immunization with a 20-mer NY-ESO-1f (NY-ESO-1 91-110) peptide.

    Science.gov (United States)

    Eikawa, Shingo; Kakimi, Kazuhiro; Isobe, Midori; Kuzushima, Kiyotaka; Luescher, Immanuel; Ohue, Yoshihiro; Ikeuchi, Kazuhiro; Uenaka, Akiko; Nishikawa, Hiroyoshi; Udono, Heiichiro; Oka, Mikio; Nakayama, Eiichi

    2013-01-15

    Immunogenicity of a long 20-mer NY-ESO-1f peptide vaccine was evaluated in a lung cancer patient TK-f01, immunized with the peptide with Picibanil OK-432 and Montanide ISA-51. We showed that internalization of the peptide was necessary to present CD8 T-cell epitopes on APC, contrasting with the direct presentation of the short epitope. CD8 T-cell responses restricted to all five HLA class I alleles were induced in the patient after the peptide vaccination. Clonal analysis showed that B*35:01 and B*52:01-restricted CD8 T-cell responses were the two dominant responses. The minimal epitopes recognized by A*24:02, B*35:01, B*52:01 and C*12:02-restricted CD8 T-cell clones were defined and peptide/HLA tetramers were produced. NY-ESO-1 91-101 on A*24:02, NY-ESO-1 92-102 on B*35:01, NY-ESO-1 96-104 on B*52:01 and NY-ESO-1 96-104 on C*12:02 were new epitopes first defined in this study. Identification of the A*24:02 epitope is highly relevant for studying the Japanese population because of its high expression frequency (60%). High affinity CD8 T-cells recognizing tumor cells naturally expressing the epitopes and matched HLA were induced at a significant level. The findings suggest the usefulness of a long 20-mer NY-ESO-1f peptide harboring multiple CD8 T-cell epitopes as an NY-ESO-1 vaccine. Characterization of CD8 T-cell responses in immunomonitoring using peptide/HLA tetramers revealed that multiple CD8 T-cell responses comprised the dominant response.

  19. Restriction of cell surface expression of Sendai virus hemagglutinin-neuraminidase glycoprotein correlates with its higher instability in persistently and standard plus defective interfering virus infected BHK-21 cells

    Energy Technology Data Exchange (ETDEWEB)

    Roux, L.; Beffy, P.; Portner, A.

    1984-10-15

    To gain an understanding of the mechanism(s) by which Sendai virus generates a persistent infection, the expression of the hemagglutinin-neuraminidase (HN) and fusion (Fo) glycoproteins at the surfaces of BHK-21 cells infected with standard virus, a mixture of standard and defective interfering (DI) particles (mixed virus infection), and during persistent infection was investigated. The expression of HN and Fo was measured on the surfaces of infected cells by the binding of anti-HN and anti-Fo monoclonal antibodies. The results show that HN expression was restricted relative to Fo during mixed virus and persistent infections. The decreased levels of HN were investigated further by pulse-chase experiments which revealed that HN has an increased turnover rate in persistently infected cells and, to a lesser extent, in mixed virus infected cells. In analyzing the (/sup 35/S)methionine-labeled protein composition of virus particles produced during the pulse-chase experiments, the increased turnover of newly synthesized HN was found to correlate with its decreased incorporation into virus particles. Interestingly, the poor HN incorporation also correlates with less efficient incorporation of the matrix M protein into virus particles.

  20. miR-181b negatively regulates activation-induced cytidine deaminase in B cells.

    Science.gov (United States)

    de Yébenes, Virginia G; Belver, Laura; Pisano, David G; González, Susana; Villasante, Aranzazu; Croce, Carlo; He, Lin; Ramiro, Almudena R

    2008-09-29

    Activated B cells reshape their primary antibody repertoire after antigen encounter by two molecular mechanisms: somatic hypermutation (SHM) and class switch recombination (CSR). SHM and CSR are initiated by activation-induced cytidine deaminase (AID) through the deamination of cytosine residues on the immunoglobulin loci, which leads to the generation of DNA mutations or double-strand break intermediates. As a bystander effect, endogenous AID levels can also promote the generation of chromosome translocations, suggesting that the fine tuning of AID expression may be critical to restrict B cell lymphomagenesis. To determine whether microRNAs (miRNAs) play a role in the regulation of AID expression, we performed a functional screening of an miRNA library and identified miRNAs that regulate CSR. One such miRNA, miR-181b, impairs CSR when expressed in activated B cells, and results in the down-regulation of AID mRNA and protein levels. We found that the AID 3' untranslated region contains multiple putative binding sequences for miR-181b and that these sequences can be directly targeted by miR-181b. Overall, our results provide evidence for a new regulatory mechanism that restricts AID activity and can therefore be relevant to prevent B cell malignant transformation.

  1. Effects of realimentation after nutrient restriction during mid- to late gestation on pancreatic digestive enzymes, serum insulin and glucose levels, and insulin-containing cell cluster morphology.

    Science.gov (United States)

    Keomanivong, F E; Camacho, L E; Lemley, C O; Kuemper, E A; Yunusova, R D; Borowicz, P P; Kirsch, J D; Vonnahme, K A; Caton, J S; Swanson, K C

    2016-04-14

    This study examined effects of stage of gestation and nutrient restriction with subsequent realimentation on maternal and foetal bovine pancreatic function. Dietary treatments were assigned on day 30 of pregnancy and included: control (CON; 100% requirements; n = 18) and restricted (R; 60% requirements; n = 30). On day 85, cows were slaughtered (CON, n = 6; R, n = 6), remained on control (CC; n = 12) and restricted (RR; n = 12), or realimented to control (RC; n = 11). On day 140, cows were slaughtered (CC, n = 6; RR, n = 6; RC, n = 5), remained on control (CCC, n = 6; RCC, n = 5) or realimented to control (RRC, n = 6). On day 254, the remaining cows were slaughtered and serum samples were collected from the maternal jugular vein and umbilical cord to determine insulin and glucose concentrations. Pancreases from cows and foetuses were removed, weighed, and subsampled for enzyme and histological analysis. As gestation progressed, maternal pancreatic α-amylase activity decreased and serum insulin concentrations increased (p ≤ 0.03). Foetal pancreatic trypsin activity increased (p enzymes are influenced by nutrient restriction and there is a potential for programming of increased foetal digestive enzyme production resulting from previous maternal nutrient restriction.

  2. Presence of viral nucleic acids in the middle ear: acute otitis media pathogen or bystander?

    Science.gov (United States)

    Chonmaitree, Tasnee; Ruohola, Aino; Hendley, J Owen

    2012-04-01

    Viruses play an important role in acute otitis media (AOM) pathogenesis, and live viruses may cause AOM in the absence of pathogenic bacteria. Detection of AOM pathogens generally relies on bacterial culture of middle ear fluid. When viral culture is used and live viruses are detected in the middle ear fluid of children with AOM, the viruses are generally accepted as AOM pathogens. Because viral culture is not sensitive and does not detect the comprehensive spectrum of respiratory viruses, polymerase chain reaction assays are commonly used to detect viral nucleic acids in the middle ear fluid. Although polymerase chain reaction assays have greatly increased the viral detection rate, new questions arise on the significance of viral nucleic acids detected in the middle ear because nucleic acids of multiple viruses are detected simultaneously, and nucleic acids of specific viruses are detected repeatedly and in a high proportion of asymptomatic children. This article first reviews the role of live viruses in AOM and presents the point-counterpoint arguments on whether viral nucleic acids in the middle ear represent an AOM pathogen or a bystander status. Although there is evidence to support both directions, helpful information for interpretation of the data and future research direction is outlined.

  3. Acting in solidarity: Testing an extended dual pathway model of collective action by bystander group members.

    Science.gov (United States)

    Saab, Rim; Tausch, Nicole; Spears, Russell; Cheung, Wing-Yee

    2015-09-01

    We examined predictors of collective action among bystander group members in solidarity with a disadvantaged group by extending the dual pathway model of collective action, which proposes one efficacy-based and one emotion-based path to collective action (Van Zomeren, Spears, Fischer, & Leach, 2004). Based on two proposed functions of social identity performance (Klein, Spears, & Reicher, 2007), we distinguished between the efficacy of collective action at consolidating the identity of a protest movement and its efficacy at achieving social change (political efficacy). We expected identity consolidation efficacy to positively predict collective action tendencies directly and indirectly via political efficacy. We also expected collective action tendencies to be positively predicted by moral outrage and by sympathy in response to disadvantaged outgroup's suffering. These hypotheses were supported in two surveys examining intentions to protest for Palestine in Britain (Study 1), and intentions to attend the June 4th vigil in Hong Kong to commemorate the Tiananmen massacre among a sample of Hong Kong citizens (Study 2). The contributions of these findings to research on the dual pathway model of collective action and the different functions of collective action are discussed.

  4. Teens’ Self-Efficacy to Deal with Dating Violence as Victim, Perpetrator or Bystander

    Science.gov (United States)

    Van Camp, Tinneke; Hébert, Martine; Guidi, Elisa; Lavoie, Francine; Blais, Martin

    2015-01-01

    Multiple studies have demonstrated that adolescent dating violence is highly prevalent and associated with internalizing and externalizing problems. A number of prevention initiatives are being implemented in North-American high schools. Such initiatives do not only aim to raise awareness among potential victims and offenders but also among peer bystanders. Since teenagers mainly reach out to their peers when experiencing adversity, it is important to address adolescents’ efficiency to deal with witnessing dating violence or with friends disclosing dating abuse, in addition to increasing ability to deal with experienced dating violence victimization or perpetration. The aim of this study is to explore adolescents’ self-efficacy to deal with dating violence victimization and perpetration in their relationships and those of their peers. A paper-and-pencil questionnaire was completed by 259 14–18 years olds in Quebec, Canada. The data allows building insight into adolescents’ confidence to reach out for help or to help others in a situation of dating violence victimization and perpetration. We also considered the impact of gender and dating victimization history. Results suggest that dating violence prevention can build on teens’ self-efficacy to deal with dating violence and offer them tools to do so efficiently. PMID:26807554

  5. Long-term moderate calorie restriction inhibits inflammation without impairing cell-mediated immunity: a randomized controlled trial in non obese humans

    Science.gov (United States)

    Calorie restriction (CR) inhibits inflammation and slows aging in many animal species, but in rodents housed in pathogen-free facilities, CR impairs immunity against certain pathogens. However, little is known about the effects of long-term moderate CR on immune function in humans. In this multi-cen...

  6. Virtual bystanders in a language lesson: examining the effect of social evaluation, vicarious experience, cognitive consistency and praising on students' beliefs, self-efficacy and anxiety in a virtual reality environment

    NARCIS (Netherlands)

    Qu, C.; Ling, Y.; Heynderickx, I.; Brinkman, W.-P.

    2015-01-01

    Bystanders in a real world's social setting have the ability to influence people’s beliefs and behavior. This study examines whether this effect can be recreated in a virtual environment, by exposing people to virtual bystanders in a classroom setting. Participants (n = 26) first witnessed virtual s

  7. Humanized mice dually challenged with R5 and X4 HIV-1 show preferential R5 viremia and restricted X4 infection of CCR5(+)CD4(+) T cells.

    Science.gov (United States)

    Terahara, Kazutaka; Ishige, Masayuki; Ikeno, Shota; Okada, Seiji; Kobayashi-Ishihara, Mie; Ato, Manabu; Tsunetsugu-Yokota, Yasuko

    2015-05-01

    CCR5-tropic (R5) immunodeficiency virus type 1 (HIV-1) strains are highly transmissible during the early stage of infection in humans, whereas CXCR4-tropic (X4) strains are less transmissible. This study aimed to explore the basis for early phase R5 and X4 HIV-1 infection in vivo by using humanized mice dually challenged with R5 HIV-1NLAD8-D harboring DsRed and X4 HIV-1(NL-E) harboring EGFP. Whereas R5 HIV-1 replicated well, X4 HIV-1 caused only transient viremia with variable kinetics; however, this was distinct from the low level but persistent viremia observed in mice challenged with X4 HIV-1 alone. Flow cytometric analysis of HIV-1-infected cells revealed that X4 HIV-1 infection of CCR5(+)CD4(+) T cells was significantly suppressed in the presence of R5 HIV-1. X4 HIV-1 was more cytopathic than R5 HIV-1; however, this was not the cause of restricted X4 HIV-1 infection because there were no significant differences in the mortality rates of CCR5(+) and CCR5(-) cells within the X4 HIV-1-infected cell populations. Taken together, these results suggest that restricted infection of CCR5(+)CD4(+) T cells by X4 HIV-1 (occurring via a still-to-be-identified mechanism) might contribute to the preferential transmission of R5 HIV-1 during the early phase of infection.

  8. A novel immunodominant CD8+ T cell response restricted by a common HLA-C allele targets a conserved region of Gag HIV-1 clade CRF01_AE infected Thais.

    Directory of Open Access Journals (Sweden)

    Supranee Buranapraditkun

    Full Text Available BACKGROUND: CD8+ T cell responses play an important role in the control of HIV-1. The extensive sequence diversity of HIV-1 represents a critical hurdle to developing an effective HIV-1 vaccine, and it is likely that regional-specific vaccine strains will be required to overcome the diversity of the different HIV-1 clades distributed world-wide. Unfortunately, little is known about the CD8+ T cell responses against CRF01_AE, which is responsible for the majority of infections in Southeast Asia. METHODOLOGY/PRINCIPAL FINDINGS: To identify dominant CD8+ T cell responses recognized in HIV-1 clade CRF01_AE infected subjects we drew upon data from an immunological screen of 100 HIV-1 clade CRF01_AE infected subjects using IFN-gamma ELISpot to characterize a novel immunodominant CD8+ T cell response in HIV-1 Gag restricted by HLA-Cw*0102 (p24, (277YSPVSILDI(285, YI9. Over 75% of Cw*0102+ve subjects targeted this epitope, representing the strongest response in more than a third of these individuals. This novel CD8 epitope was located in a highly conserved region of HIV-1 Gag known to contain immunodominant CD8 epitopes, which are restricted by HLA-B*57 and -B*27 in clade B infection. Nonetheless, viral escape in this epitope was frequently observed in Cw*0102+ve subjects, suggestive of strong selection pressure being exerted by this common CD8+ T cell response. CONCLUSIONS/SIGNIFICANCE: As HLA-Cw*0102 is frequently expressed in the Thai population (allelic frequency of 16.8%, this immunodominant Cw*0102-restricted Gag epitope may represent an attractive candidate for vaccines specific to CRF01_AE and may help facilitate further studies of immunopathogenesis in this understudied HIV-1 clade.

  9. Signalling pathways induced in cells exposed to medium from irradiated cells

    Energy Technology Data Exchange (ETDEWEB)

    Lyng, F.M.; Maguire, P. (Radiation and Environmental Science Centre, Focas Institute, Dublin Institute of Technology, Dublin (Ireland)); McClean, B.; Seymour, C.; Mothersill, C. (St Luke' s Hospital, Dublin (Ireland))

    2008-12-15

    In recent years, radiation induced bystander effects have been reported in cells