Sample records for lymphocyte cytotoxicity assay

  1. ELISPOT Assay for Monitoring Cytotoxic T Lymphocytes (CTL Activity in Cancer Vaccine Clinical Trials

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    Thomas J. Sayers


    Full Text Available The profiling and monitoring of immune responses are key elements in the evaluation of the efficacy and development of new biotherapies, and a number of assays have been introduced for analyzing various immune parameters before, during, and after immunotherapy. The choice of immune assays for a given clinical trial depends on the known or suggested immunomodulating mechanisms associated with the tested therapeutic modality. Cell-mediated cytotoxicity represents a key mechanism in the immune response to various pathogens and tumors. Therefore, the selection of monitoring methods for the appropriate assessment of cell-mediated cytotoxicity is thought to be crucial. Assays that can detect both cytotoxic T lymphocytes (CTL frequency and function, such as the IFN-γ enzyme-linked immunospot assay (ELISPOT have gained increasing popularity for monitoring clinical trials and in basic research. Results from various clinical trials, including peptide and whole tumor cell vaccination and cytokine treatment, have shown the suitability of the IFN-γ ELISPOT assay for monitoring T cell responses. However, the Granzyme B ELISPOT assay and Perforin ELISPOT assay may represent a more direct analysis of cell-mediated cytotoxicity as compared to the IFN-γ ELISPOT, since Granzyme B and perforin are the key mediators of target cell death via the granule-mediated pathway. In this review we analyze our own data and the data reported by others with regard to the application of various modifications of ELISPOT assays for monitoring CTL activity in clinical vaccine trials.

  2. A three-dimensional organotypic assay to measure target cell killing by cytotoxic T lymphocytes.

    NARCIS (Netherlands)

    Weigelin, B.; Friedl, P.H.A.


    Cytotoxic T lymphocytes (CTL) mediate antigen- and cell-cell contact dependent killing of target cells, such as cancer cells and virus-infected cells. In vivo, this process requires the active migration of CTL towards and away from target cells. We here describe an organotypic 3D collagen matrix

  3. Measuring melanoma-specific cytotoxic T lymphocytes elicited by dendritic cell vaccines with a tumor inhibition assay in vitro. (United States)

    Paczesny, Sophie; Shi, Honhgzhen; Saito, Hiroaki; Mannoni, Patrice; Fay, Joseph; Banchereau, Jacques; Palucka, A Karolina


    Improving cancer vaccines depends on assays measuring elicited tumor-specific T-cell immunity. Cytotoxic effector cells are essential for tumor clearance and are commonly evaluated using 51Cr release from labeled target cells after a short (4 hours) incubation with T cells. The authors used a tumor inhibition assay (TIA) that assesses the capacity of cytotoxic T lymphocytes (CTLs) to control the survival/growth of EGFP-labeled tumor cell lines. TIA was validated using CD8+ T cells primed in vitro against melanoma and breast cancer cells. TIA was then used to assess the CTL function of cultured CD8+ T cells isolated from patients with metastatic melanoma who underwent vaccination with peptide-pulsed CD34+ HPCs-derived DCs. After the DC vaccination, T cells from six of eight patients yielded CTLs that could inhibit the survival/growth of melanoma cells. The results of TIA correlated with killing of tumor cells in a standard 4-hour 51Cr release assay, yet TIA allowed detection of CTL activities that appeared marginal in the 51Cr release assay. Thus, TIA might prove valuable for measuring spontaneous and induced antigen-specific cytotoxic T cells.

  4. Study of the genotoxic and cytotoxic effects of the α-, β-, and γ- Hexachlorocyclohexane isomers in human lymphocyte cells using the cytokinesis-block micronucleus assay. (United States)

    Ennaceur, Soukaina


    The genotoxic potential of hexachlorocyclohexane (HCH) isomers (α-, β-, and γ-) which are organochlorine pesticides was tested in peripheral blood lymphocyte cultures from two donors by using the cytokinesis-block micronucleus assay. Micronucleus (MN) frequency, binucleated cells with micronucleus (BNMN), and cytokinesis-blocked proliferation index (CBPI) were determined as genotoxic and cytotoxic endpoints. At the concentration ranges tested (12.5-100 μg.L (-1)), all HCH isomers induced dose-dependent cytotoxic effects, γ-HCH being the most toxic. This isomer was also able to induce significant increase in MN frequency and BNMN cells indicating a genotoxic potential at 50 and 100 μg.L (-1). The genotoxic test of β-HCH showed a positive induction of MN and BNMN cells at the highest concentration of 100 μg.L (-1) and a significant cytotoxicity at 50 μg.L (-1). Under the experimental condition used, α-HCH was unable to induce any significant increase in MN frequency confirming that α-HCH is a non-genotoxic agent.

  5. Computer-based design of an HLA-haplotype and HIV-clade independent cytotoxic T-lymphocyte assay for monitoring HIV-specific immunity. (United States)

    Amicosante, Massimo; Gioia, Cristiana; Montesano, Carla; Casetti, Rita; Topino, Simone; D'Offizi, Gianpiero; Cappelli, Giulia; Ippolito, Giuseppe; Colizzi, Vittorio; Poccia, Fabrizio; Pucillo, Leopoldo P.


    BACKGROUND: Human immunodeficiency virus (HIV)- specific CD8-positive cytotoxic T-lymphocytes (CTL) play a key role in controlling HIV infection. Monitoring CTL response could be clinically relevant during structured therapy interruption (STI), HIV exposure, and vaccine trials. However, HLA patients' restriction and HIV variability limited the development of a CTL assay with broad specificity. MATERIALS AND METHODS: We designed an HLA-class I/HIV-1 clade independent assay for assessing HIV- specific CTL by using a computer-assisted selection ofthe CTL epitopes. Twenty-eight 15-mers were selected by peptide-binding motifs analysis using different databases (HIV-Immunology Database, SYFPEITHI, BIMAS). Altogether they putatively bind to more than 90% of HLA haplotypes in different populations, with an overall HIV-1 variability below 9%. The peptide pool was used as an antigen in an intracellular cytokine staining (ICS) assay for quantifying HIV-specific CTL response. RESULTS: The test can be performed using both fresh and cryopreserved peripheral blood mononuclear cells (PBMC), whereas GAG protein as antigen works only on fresh PBMC. A significantly higher CTL response with respect to HIV-negative controls was detected in all HIV-1 infected subjects of two groups of patients with different ethnicities (Caucasians and Africans) and coming from areas with different HIV-1 clade prevalences (clade B and A/G, respectively). In Caucasian patients, after month of STI, the number of HIV-1 specific CTL (2,896 +/- 2,780 IFN-gamma specific CD8 cells/ml) was significantly higher than that found at enrolment (2,125 +/- 4,426 IFN-gamma specific CD8 cells/ml, p< 0.05). CONCLUSIONS: These data indicate that this CTL assay is broadly specific and could represent a useful clinical tool for HIV immunodiagnostic independent of HLA-haplotype and HIV-clade variabilities. PMID:12606814

  6. In vitro genotoxicity and cytotoxicity of five new chemical compounds of plant origin by means of the human lymphocyte micronucleus assay. (United States)

    Scarpato, R; Pistelli, L; Bertoli, A; Nieri, E; Migliore, L


    The micronucleus test in human peripheral lymphocytes is widely used in toxicology for the assessment of the genotoxic profile of chemical compounds of environmental concern. The aim of this study was to evaluate the genotoxic, cytotoxic and antimitotic activity of five new compounds isolated from Prunus africana Hook or from Bupleurum fruticosum L. The experiments were conducted only in vitro. Results showed that none of the plant extracts, tested over a wide range of concentrations, increased the frequency of micronuclei. Only compounds 2 and 5 were found to be toxic for phytohaemagglutinin-stimulated lymphocytes at the maximum dose used. reserved.

  7. Cell Death Mechanisms Induced by Cytotoxic Lymphocytes

    Institute of Scientific and Technical Information of China (English)

    Ch(a)vez-Gal(a)n L; Arenas-Del Angel MC; Zenteno E; Ch(a)vez R; Lascurain R


    One of the functions of the immune system is to recognize and destroy abnormal or infected cells to maintain homeostasis. This is accomplished by cytotoxic lymphocytes. Cytotoxicity is a highly organized multifactor process. Here, we reviewed the apoptosis pathways induced by the two main cytotoxic lymphocyte subsets, natural killer (NK) cells and CD8+T cells. In base to recent experimental evidence, we reviewed NK receptors involved in recognition of target-cell, as well as lytic molecules such as perforin, granzymes-A and -B, and granulysin. In addition, we reviewed the Fas-FasL intercellular linkage mediated pathway, and briefly the cross-linking of tumor necrosis factor (TNF) and TNF receptor pathway. We discussed three models of possible molecular interaction between lyric molecules from effector cytotoxic cells and target-cell membrane to induction of apoptosis.

  8. Targeting cytotoxic T lymphocytes for cancer immunotherapy


    Maher, J; Davies, E. T.


    In light of their preeminent role in cellular immunity, there is considerable interest in targeting of cytotoxic T-lymphocytes to cancer. This review summarises the active and passive immunotherapeutic approaches under development to achieve this goal, emphasising how recent advances in tumour immunology and gene transfer have impacted upon this field.

  9. Molecular Mechanisms of Lymphocyte-Mediated Cytotoxicity

    Institute of Scientific and Technical Information of China (English)

    Zusen Fan; Qixiang Zhang


    Granule-mediated cytotoxicity is the major mechanism for lymphocytes to kill viruses, intracellular bacteria and tumors. The cytotoxic granules move to the immunological synapse by exocytosis after recognition of a killer cell.The contents of the granules are delivered into target cells with the help of perforin by endocytosis. A group of serine protease granzymes cleave their critical substrates to initiate DNA damage and cell death. The most abundant granzymes are granzyme A and B. They induce cell death through alternate and nonoverlapping pathways. The substrates and functions of the majority of the orphan granzymes have not yet been identified. It is possible that the diversity of granzymes provides fail-safe mechanisms for killing viruses and tumor cells.

  10. A novel method for producing target cells and assessing cytotoxic T lymphocyte activity in outbred hosts

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    Bendinelli Mauro


    Full Text Available Abstract Background Cytotoxic T lymphocytes play a crucial role in the immunological control of microbial infections and in the design of vaccines and immunotherapies. Measurement of cytotoxic T lymphocyte activity requires that the test antigen is presented by target cells having the same or compatible class I major hystocompatibility complex antigens as the effector cells. Conventional assays use target cells labeled with 51chromium and infer cytotoxic T lymphocyte activity by measuring the isotope released by the target cells lysed following incubation with antigen-specific cytotoxic T lymphocytes. This assay is sensitive but needs manipulation and disposal of hazardous radioactive reagents and provides a bulk estimate of the reporter released, which may be influenced by spontaneous release of the label and other poorly controllable variables. Here we describe a novel method for producing target in outbred hosts and assessing cytotoxic T lymphocyte activity by flow cytometry. Results The method consists of culturing skin fibroblasts, immortalizing them with a replication defective clone of simian virus 40, and finally transducing them with a bicistronic vector encoding the target antigen and the reporter green fluorescent protein. When used in a flow cytometry-based assay, the target cells obtained with this method proved valuable for assessing the viral envelope protein specific cytotoxic T lymphocyte activity in domestic cats acutely or chronically infected with feline immunodeficiency virus, a lentivirus similar to human immunodeficiency virus and used as animal model for AIDS studies. Conclusion Given the versatility of the bicistronic vector used, its ability to deliver multiple and large transgenes in target cells, and its extremely wide cell specificity when pseudotyped with the vesicular stomatitis virus envelope protein, the method is potentially exploitable in many animal species.

  11. Carbon nanotubes enhance cytotoxicity mediated by human lymphocytes in vitro.

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    Zhao Sun

    Full Text Available With the expansion of the potential applications of carbon nanotubes (CNT in biomedical fields, the toxicity and biocompatibility of CNT have become issues of growing concern. Since the immune system often mediates tissue damage during pathogenesis, it is important to explore whether CNT can trigger cytotoxicity through affecting the immune functions. In the current study, we evaluated the influence of CNT on the cytotoxicity mediated by human lymphocytes in vitro. The results showed that while CNT at low concentrations (0.001 to 0.1 µg/ml did not cause obvious cell death or apoptosis directly, it enhanced lymphocyte-mediated cytotoxicity against multiple human cell lines. In addition, CNT increased the secretion of IFN-γ and TNF-α by the lymphocytes. CNT also upregulated the NF-κB expression in lymphocytes, and the blockage of the NF-κB pathway reduced the lymphocyte-mediated cytotoxicity triggered by CNT. These results suggest that CNT at lower concentrations may prospectively initiate an indirect cytotoxicity through affecting the function of lymphocytes.

  12. Enhancement of human natural cytotoxicity by Plasmodium falciparum antigen activated lymphocytes

    DEFF Research Database (Denmark)

    Theander, T G; Pedersen, B K; Bygbjerg, I C


    Mononuclear cells (MNC) isolated from malaria immune donors and from donors never exposed to malaria were stimulated in vitro with soluble purified Plasmodium falciparum antigens (SPag) or PPD. After 7 days of culture the proliferative response and the cytotoxic activity against the natural killer...... cell (NK cell) sensitive cell line, K562, were measured. It was found that SPag stimulation enhanced cytotoxic activity of MNC from donors whose lymphocytes exhibited a strong proliferative response to the antigen. MNC with low proliferative responsiveness showed increased cytotoxic activity if the MNC...... were preincubated with interleukin 2 (IL-2) for one hour before the start of the cytotoxic assay. SPag activation did not enhance the cytotoxic activity of MNC which did not respond to the antigen in the proliferation assay, and preincubation of these cells with IL-2 did not increase the activity. PPD...

  13. Antigen processing influences HIV-specific cytotoxic T lymphocyte immunodominance

    DEFF Research Database (Denmark)

    Tenzer, Stefan; Wee, Edmund; Burgevin, Anne


    Although cytotoxic T lymphocytes (CTLs) in people infected with human immunodeficiency virus type 1 can potentially target multiple virus epitopes, the same few are recognized repeatedly. We show here that CTL immunodominance in regions of the human immunodeficiency virus type 1 group-associated ......Although cytotoxic T lymphocytes (CTLs) in people infected with human immunodeficiency virus type 1 can potentially target multiple virus epitopes, the same few are recognized repeatedly. We show here that CTL immunodominance in regions of the human immunodeficiency virus type 1 group...

  14. Protective Role of Cytotoxic T Lymphocytes in Filovirus Hemorrhagic Fever

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    Kelly Lyn Warfield


    Full Text Available Infection with many emerging viruses, such as the hemorrhagic fever disease caused by the filoviruses, Marburg (MARV, and Ebola virus (EBOV, leaves the host with a short timeframe in which to mouse a protective immune response. In lethal cases, uncontrolled viral replication and virus-induced immune dysregulation are too severe to overcome, and mortality is generally associated with a lack of notable immune responses. Vaccination studies in animals have demonstrated an association of IgG and neutralizing antibody responses against the protective glycoprotein antigen with survival from lethal challenge. More recently, studies in animal models of filovirus hemorrhagic fever have established that induction of a strong filovirus-specific cytotoxic T lymphocyte (CTL response can facilitate complete viral clearance. In this review, we describe assays used to discover CTL responses after vaccination or live filovirus infection in both animal models and human clinical trials. Unfortunately, little data regarding CTL responses have been collected from infected human survivors, primarily due to the low frequency of disease and the inability to perform these studies in the field. Advancements in assays and technologies may allow these studies to occur during future outbreaks.

  15. The Use of Isolated Human Lymphocytes in Mycotoxin Cytotoxicity Testing

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    Mike F. Dutton


    Full Text Available The cytotoxicity of selected mycotoxins against isolated human lymphocytes was investigated, as a means of detecting mycotoxins in extracts derived from cereal samples. The methodology was based on the ability of viable cells to reduce methyl tetrazolium bromide to a purple formazan dye that could be quantitated by spectrophometric means and hence give a measure of the cytotoxicity of added substances. The results showed that there was good correlation with the occurrence of identified mycotoxins with only a minimum of false positives. For example, of the 13 samples of barley or barley derivatives that were positive for the mycotoxins, fumonisin B1 (FB1 deoxynivalenol (DON and ochratoxin A (OTA, all gave positive cytotoxicity responses. Two samples negative for mycotoxins gave no cytotoxicity responses. There was little variation between the results for lymphocytes drawn from the same healthy volunteer on three different occasions. Furthermore, for two of the mycotoxins tested (FB1 and DON it was possible to correlate general levels of mycotoxins present to the cytotoxic response of the lymphocytes but not for OTA, where it was concluded that interfering substances prevented direct correlation. It was concluded that this method was suited for general application as it could handle relatively high number of samples in a short period of time.

  16. Concanavalin A-induced activation of lymphocytic choriomeningitis virus memory lymphocytes into specifically cytotoxic T cells

    DEFF Research Database (Denmark)

    Marker, O; Thomsen, Allan Randrup; Andersen, G T


    When spleen cells, which have been primed to Lymphocytic Choriomeningitis (LCM) virus during a primary infection several months previously, are stimulated in vitro with Con A. highly specific secondary cytotoxic effector cells are generated. The degree of cytotoxicity revealed by such Con A......-stimulated cells is higher than that of non-incubated spleen cells harvested nine days following the primary infection, and the effect is totally inhibited by anti-theta serum plus complement treatment of the effector cells immediately before the cytotoxic test....

  17. Flow cytometric assay detecting cytotoxicity against human endogenous retrovirus antigens expressed on cultured multiple sclerosis cells

    DEFF Research Database (Denmark)

    Møller-Larsen, A; Brudek, T; Petersen, T


    as control antibody. Without antibodies this system is suitable for analyses of natural killer cell activity. In optimization of the assay we have used effector lymphocytes from healthy donors. The most effective effector cells are CD56(+) cells. CD8(+) T cells also express CD107a in ADCC. Using the adapted......Damage of target cells by cytotoxicity, either mediated by specific lymphocytes or via antibody-dependent reactions, may play a decisive role in causing the central nervous system (CNS) lesions seen in multiple sclerosis (MS). Relevant epitopes, antibodies towards these epitopes and a reliable...... assay are all mandatory parts in detection and evaluation of the pertinence of such cytotoxicity reactions. We have adapted a flow cytometry assay detecting CD107a expression on the surface of cytotoxic effector cells to be applicable for analyses of the effect on target cells from MS patients...

  18. The cytotoxic T lymphocyte immune synapse at a glance. (United States)

    Dieckmann, Nele M G; Frazer, Gordon L; Asano, Yukako; Stinchcombe, Jane C; Griffiths, Gillian M


    The immune synapse provides an important structure for communication with immune cells. Studies on immune synapses formed by cytotoxic T lymphocytes (CTLs) highlight the dynamic changes and specialised mechanisms required to facilitate focal signalling and polarised secretion in immune cells. In this Cell Science at a Glance article and the accompanying poster, we illustrate the different steps that reveal the specialised mechanisms used to focus secretion at the CTL immune synapse and allow CTLs to be such efficient and precise serial killers.

  19. C1-esterase inhibitor blocks T lymphocyte proliferation and cytotoxic T lymphocyte generation in vitro

    DEFF Research Database (Denmark)

    Nissen, Mogens Holst; Bregenholt, S; Nording, J A


    We have previously shown that activated C1s complement and activated T cells cleave beta2-microglobulin (beta2m) in vitro leading to the formation of desLys58 beta2m. This process can specifically be inhibited by C1-esterase inhibitor (C1-inh). Furthermore we showed that exogenously added desLys58...... beta2m in nanomolar amounts to a one-way allogenic mixed lymphocyte culture (MLC) increased the endogenous production of IL-2 and the generation of allo-specific cytotoxic T lymphocytes. C1-inh was purified from fresh human plasma and added to human or murine MLC and mitogen-stimulated lymphocyte...... of allospecific cytotoxic activity, and changed the endogenous production of IL-2, IL-4, IL-10, IL-12 and IFN-gamma. These data clearly demonstrate a regulatory function of C1-inh on T cell-mediated immune functions....

  20. Cytotoxicity and genotoxicity of gliotoxin on human lymphocytes in vitro

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    Mohammed Adel Nouri


    Full Text Available The cytotoxic effects on human lymphocytes of two gliotoxin samples (one pure sample produced in the laboratory for this study, and one sample purchased from a standard source were assessed at four different concentrations (25, 50, 100 and 200 ng/ml using the methylthiazol tetrazolium (MTT bioassay. The results showed that growth was inhibited by 21, 39.10, 61.99 and 87.45% for each of the four concentrations of the pure sample, respectively, and by 17.89, 34.92, 58.34 and 85.22% respectively, in the case of the standard purchased sample. Deoxyribonucleic acid (DNA was extracted from the lymphocytes and analysed by electrophoresis on a 1% agarose gel. Gliotoxin appeared to have the ability to degrade or damage the DNA. The present study showed that both the growth inhibition and DNA damage experienced by the human lymphocytes increased linearly with increasing concentrations of toxin.

  1. Construction of HA-1-DC Nucleic-acid Vaccine and Induction of Specific Cytotoxic T Lymphocytes

    Institute of Scientific and Technical Information of China (English)

    WANG Yaya; ZHANG Donghua; HU Jinmei; LIU Wenli; ZHOU hongsheng; ZHANG Lu; LIU Dan; HUANG Zhenqian; TAN Huo


    An HA-1-DC nucleic-acid vaccine was constructed to induce anti-leukemia effect after hematopoietic stem cell transplantation (HSCT). DCs were generated from HSCT donors in vitro, and its immunologic activity was assayed by using flow cytometry and mixed lymphocytes reaction.HA-1 gene was electroporated into the cultured DCs to construct a DC nucleic-acid vaccine. After transfection for 48 h, the expression of HA-1 protein could be detected by using Western blot. The DCs were cultured with syngenic lymphocytes to induce specific cytotoxic T lymphocytes (CTLs).The cytoxicity of the CTLs was detected by LDH assay. The results showed that The DCs derived from peripheral blood monocytes (PBMCs) expressed the phenotype of DCs, and were effective in stimulating proliferation of the allogenic lymphocytes. After electroporating for 48-h, HA-1 protein was detected by using Western blot. The cytotoxity of inducing CTLs was higher than the control group. It was suggested that minor histocompatibility antigen HA-1 could be considered as a target of immunotherapy against leukemia after HSCT.

  2. Cytotoxic T lymphocytes specific for the simian immunodeficiency virus. (United States)

    Letvin, N L; Schmitz, J E; Jordan, H L; Seth, A; Hirsch, V M; Reimann, K A; Kuroda, M J


    A non-human primate model for acquired immunodeficiency syndrome (AIDS), the simian immunodeficiency virus (SIV)-infected rhesus monkey, was used to explore the role of the AIDS virus-specific cytotoxic T-lymphocyte (CTL) response in disease pathogenesis. This CTL response was measured using the major histocompatibility complex (MHC) class I/peptide tetramer technology. Large numbers of tetramer-binding CD8+ T lymphocytes were demonstrable not only in the peripheral blood, but in lymph nodes and even in semen of chronically SIV-infected monkeys. The central role of these effector T lymphocytes in containing SIV spread during primary infection was demonstrated by showing that early SIV clearance during primary infection correlated with the emergence of the tetramer binding CD8+ T lymphocytes and that in vivo depletion of CD8+ lymphocytes eliminated the ability of the infected monkeys to contain SIV replication. These observations suggest that an effective AIDS vaccine should elicit a potent virus-specific CTL response. In fact, a live, recombinant SIV vaccine constructed using the attenuated pox virus vector modified vaccinia Ankara (MVA) elicited a high-frequency CTL response, comparable in magnitude to that elicited by SIV infection itself. This suggests that vaccine modalities such as MVA may prove useful in creating an effective human immunodeficiency virus (HIV) vaccine. These studies also indicate the power of both the SIV/macaque model and MHC class I/peptide tetramers for assessing AIDS vaccine strategies.

  3. Direct Microbicidal Activity of Cytotoxic T-Lymphocytes

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    Paul Oykhman


    Full Text Available Cytotoxic T-lymphocytes (CTL are famous for their ability to kill tumor, allogeneic and virus-infected cells. However, an emerging literature has now demonstrated that CTL also possess the ability to directly recognize and kill bacteria, parasites, and fungi. Here, we review past and recent findings demonstrating the direct microbicidal activity of both CD4+ and CD8+ CTL against various microbial pathogens. Further, this review will outline what is known regarding the mechanisms of direct killing and their underlying signalling pathways.

  4. Syntaxin 8 is required for efficient lytic granule trafficking in cytotoxic T lymphocytes. (United States)

    Bhat, Shruthi S; Friedmann, Kim S; Knörck, Arne; Hoxha, Cora; Leidinger, Petra; Backes, Christina; Meese, Eckart; Keller, Andreas; Rettig, Jens; Hoth, Markus; Qu, Bin; Schwarz, Eva C


    Cytotoxic T lymphocytes (CTL) eliminate pathogen-infected and cancerous cells mainly by polarized secretion of lytic granules (LG, containing cytotoxic molecules like perforin and granzymes) at the immunological synapse (IS). Members of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) family are involved in trafficking (generation, transport and fusion) of vesicles at the IS. Syntaxin 8 (Stx8) is expressed in LG and colocalizes with the T cell receptor (TCR) upon IS formation. Here, we report the significance of Stx8 for human CTL cytotoxicity. We found that Stx8 mostly localized in late, recycling endosomal and lysosomal compartments with little expression in early endosomal compartments. Down-regulation of Stx8 by siRNA resulted in reduced cytotoxicity. We found that following perforin release of the pre-existing pool upon target cell contact, Stx8 down-regulated CTL regenerate perforin pools less efficiently and thus release less perforin compared to control CTL. CD107a degranulation, real-time and end-point population cytotoxicity assays, and high resolution microscopy support our conclusion that Stx8 is required for proper and timely sorting and trafficking of cytotoxic molecules to functional LG through the endosomal pathway in human CTL.

  5. In vitro cytotoxic, genotoxic and antioxidant/oxidant effects of guaiazulene on human lymphocytes

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    Başak Toğar


    Full Text Available The aim of this study was to evaluate for the cytotoxicity, genotoxicity and antioxidant/oxidant activity of GYZ on human peripheral blood lymphocytes (PBLs. Guaiazulene (GYZ was added into culture tubes at various concentrations (0-400 µg/mL-1. Cytotoxicity against the human lymphocytes cultures was examined by lactate dehydrogenase (LDH release assay. The proliferative response was estimated by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide (MTT assay. Antioxidant/oxidant activity was evaluated by measuring the total oxidant status (TOS and total antioxidant capacity (TAC levels. Micronucleus (MN and chromosomal aberration (CA tests were used in genotoxicity studies. The results showed that GYZ caused cytotoxicity in the PBLs at high concentrations, but TOS level were not affected, while the level of TAC was significantly increased. GYZ also did not induce chromosomal aberrations when compared to that of the control group. Results this study clearly revealed that GYZ was not genotoxic and also increased the capacity of the antioxidant in the culture of human PBL cells. This report is first report on the impact of GYZ on human PBL cells.

  6. Geno- and cytotoxicity of salinomycin in human nasal mucosa and peripheral blood lymphocytes. (United States)

    Scherzad, Agmal; Hackenberg, Stephan; Schramm, Carolin; Froelich, Katrin; Ginzkey, Christian; Hagen, Rudolf; Kleinsasser, Norbert


    Salinomycin is usually applied in stock breading but has also been described as a promising agent against cancer stem cells (CSC). However, knowledge about the toxicity of this ionophor substance is incomplete. The aim of this study was to investigate cyto- and genotoxic effects of salinomycin in human non-malignant cells. Primary human nasal mucosa cells (monolayer and mini organ cultures) and peripheral blood lymphocytes from 10 individuals were used to study the cytotoxic effects of salinomycin (0.1-175 μM) by annexin-propidiumiodide- and MTT-test. The comet assay was performed to evaluate DNA damage. Additionally, the secretion of interleukin-8 was analyzed by ELISA. Flow cytometry and MTT assay revealed significant cytotoxic effects in nasal mucosa cells and lymphocytes at low salinomycin concentrations of 10-20 μM. No genotoxic effects could be observed. IL-8 secretion was elevated at 5 μM. Salinomycin-induced cytotoxic and pro-inflammatory effects were seen at concentrations relevant for anti-cancer treatment. Concurrent to the evaluation of salinomycin application in experimental oncology, adverse effects in non-malignant cells need to be monitored and reduced as much as possible. Further studies are also warranted to evaluate the toxic effects in a variety of human cell systems, e.g., liver, kidney and muscle cells.

  7. Serglycin determines secretory granule repertoire and regulates natural killer cell and cytotoxic T lymphocyte cytotoxicity. (United States)

    Sutton, Vivien R; Brennan, Amelia J; Ellis, Sarah; Danne, Jill; Thia, Kevin; Jenkins, Misty R; Voskoboinik, Ilia; Pejler, Gunnar; Johnstone, Ricky W; Andrews, Daniel M; Trapani, Joseph A


    The anionic proteoglycan serglycin is a major constituent of secretory granules in cytotoxic T lymphocyte (CTL)/natural killer (NK) cells, and is proposed to promote the safe storage of the mostly cationic granule toxins, granzymes and perforin. Despite the extensive defects of mast cell function reported in serglycin gene-disrupted mice, no comprehensive study of physiologically relevant CTL/NK cell populations has been reported. We show that the cytotoxicity of serglycin-deficient CTL and NK cells is severely compromised but can be partly compensated in both cell types when they become activated. Reduced intracellular granzyme B levels were noted, particularly in CD27(+) CD11b(+) mature NK cells, whereas serglycin(-/-) TCR-transgenic (OTI) CD8 T cells also had reduced perforin stores. Culture supernatants from serglycin(-/-) OTI T cells and interleukin-2-activated NK contained increased granzyme B, linking reduced storage with heightened export. By contrast, granzyme A was not significantly reduced in cells lacking serglycin, indicating differentially regulated trafficking and/or storage for the two granzymes. A quantitative analysis of different granule classes by transmission electronmicroscopy showed a selective loss of dense-core granules in serglycin(-/-) CD8(+) CTLs, although other granule types were maintained quantitatively. The findings of the present study show that serglycin plays a critical role in the maturation of dense-core cytotoxic granules in cytotoxic lymphocytes and the trafficking and storage of perforin and granzyme B, whereas granzyme A is unaffected. The skewed retention of cytotoxic effector molecules markedly reduces CTL/NK cell cytotoxicity, although this is partly compensated for as a result of activating the cells by physiological means.

  8. PHA-induced cytotoxicity of human lymphocytes against adherent hela-cells

    NARCIS (Netherlands)

    Huges-Law, G.; de Gast, G. C.; The, T. Hauw


    The conditions for a phytohaemagglutinin(PHA)-induced cytotoxicity test of human peripheral blood lymphocytes were investigated. [3H]thymidine prelabelled HeLa cells were used as target cells. Stimulation with 10 μl PHA/ml during 24 h gave the best measure of lymphocyte cytotoxic capacity. Supernata

  9. In-vitro cytotoxicity of aflatoxin B1 to broiler lymphocytes of broiler chickens

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    CEP Zimmermann


    Full Text Available The aim of the present work was to study the in-vitro cytotoxic effects of different concentrations of aflatoxin B1 (AFB1 on broiler lymphocytes. Lymphocyte-rich mononuclear cells were separated by Ficoll-Histopaque density and cultured in 96-wellplates containing the evaluated AFB1 concentrations in 5% CO2 atmosphere at 39°C. Thereafter, MTT, PicoGreen, and reactive oxygen species assays were performed. Cell viability decreased in the presence of 10 µg/mL AFB1 at 48 h (p < 0.05 and of 10 and 20 µg/mL AFB1 at 72 h (p < 0.01 and p < 0.001, respectively when compared to the control (0 µg/mL. However, a dose-dependent increase in the cell-free DNA at 24 h was observed at 1, 10 and 20 µg/mL (p < 0.001. ROS formation significantly increased at 24 h at all concentrations (p < 0.001. The in-vitro results demonstrate that AFB1 is cytotoxic and causes biomolecular oxidative damage in broiler lymphocytes.

  10. In vitro mutagenicity and genotoxicity study of a number of short-chain chlorinated hydrocarbons using the micronucleus test and the alkaline single cell gel electrophoresis technique (Comet assay) in human lymphocytes: a structure-activity relationship (QSAR) analysis of the genotoxic and cytotoxic potential. (United States)

    Tafazoli, M; Baeten, A; Geerlings, P; Kirsch-Volders, M


    Using the micronucleus (MN) test and the alkaline single cell gel electrophoresis (Comet) assay, potential mutagenicity (MN formation), genotoxicity (DNA breakage capacity) and cytotoxicity (cell proliferation reduction) of five chlorinated hydrocarbons (carbon tetrachloride, hexachloroethane, 1,2-dichloroethane, 1-chlorohexane and 2,3-dichlorobutane) have been evaluated in isolated human lymphocytes. With the MN test a low but statistically significant mutagenic activity was detected for all tested substances (except 2,3-dichlorobutane) with one out of the two donors and in the presence or absence of an exogenous metabolic activation system (S9 mix). However, at the concentration ranges tested none of the positive compounds induced a clear dose-dependent mutagenic effect. The Comet assay detected a strong DNA damaging effect for 1-chlorohexane, 2,3-dichlorobutane and 1,2-dichloroethane, but not for carbon tetrachloride and hexachloroethane. The influence of metabolism on the genotoxic activity of the chemicals was more clear in the Comet assay than in the MN test. The experimental genotoxicity and cytotoxicity data obtained in this study, together with data on five more related chemicals previously investigated, and their physico-chemical descriptors or electronic parameters have been used for QSAR analysis. The QSAR analysis high-lighted that the toxicity of the tested compounds was influenced by different parameters, like lipophilicity (logP), electron donor ability (charge) and longest carbon-chlorine (LBC-Cl) bond length. In addition, steric parameters, like molar refractivity (MR) and LBC-Cl, and electronic parameters, like ELUMO (energy of the lowest unoccupied molecular orbital, indicating electrophilicity), were predominant factors discriminating genotoxins from non-genotoxins in the presence but not in the absence of S9 mix. Although a limited number of compounds have been examined and cytotoxicity and genotoxicity were identified in two different

  11. Bioluminescent assay for human lymphocyte blast transformation. (United States)

    Bulanova, E G; Budagyan, V M; Romanova, N A; Brovko LYu; Ugarova, N N


    One of the basic tests of in vitro evaluation of immune cell functional activity is a proliferative response of lymphocytes on the action of external stimuli such as mitogenic lectines, antigens, etc. We compared two methods used to assess the lymphocyte functional status. (1) [3H]thymidine incorporation and (2) bioluminescence for determination of intracellular ATP in blast cells. Comparison has been done for healthy donors and patients with proven low immunological status. The proposed bioluminescent method for evaluation of the proliferative response was shown to be sensitive enough for diagnostic purposes. This method allows one to process a large number of samples at the same time and correlates highly with the radionuclide test use hazardous radioactive materials.

  12. Therapeutic potential of CD8+ cytotoxic T lymphocytes in SLE☆ (United States)

    Puliaeva, I.; Puliaev, R.; Via, C.S.


    Recent evidence supports the idea that following a break in tolerance, CD8 cytotoxic T lymphocytes (CTL) may be an important but unrecognized mechanism for limiting expansion of autoreactive B cells. Failure of this mechanism could allow persistence of CD4 T cell driven polyclonal B cell activation resulting in clinical lupus. Although CD8 CTL failure may occur early in disease, work in mice supports the concept that therapeutic CTL enhancement may be both practical and beneficial in lupus. Devising such therapy for humans will first require an understanding of the in vivo mechanisms critical in CTL expansion and down regulation, particularly in the lupus setting which may differ from CTL generation in other clinical settings (e.g. tumors, infections). PMID:18725326

  13. In vitro cytotoxic activity of equine lymphocytes on equine herpesvirus-1 infected allogenic fibroblasts


    Edens, Lucy Marie


    The objectives of this study were to: 1) develop a technique to analyze the in vitro cytotoxic activity of lymphocytes from adult horses against equine herpes virus-1 (EHV-1) infected allogenic equine dermal fibroblasts (EDF); 2) evaluate the ability of a 72 hour in vitro incubation with interleukin-2 (I L-2) to enhance the lymphocytic cytolytic activity against EHV-1 infected EDF; 3) compare the cytotoxic activity among lymphocytes isolated from pregnant mares and non-pregnant...

  14. Cytotoxic T lymphocyte activity in children infected with HIV. (United States)

    Froebel, K S; Aldhous, M C; Mok, J Y; Hayley, J; Arnott, M; Peutherer, J F


    Of the Edinburgh cohort of approximately 130 children born to HIV-infected women, 9 are infected and alive. This article describes results from the first 18 months of a natural history study of seven of these, and two adopted children, studying the CD8 T cell-mediated cytotoxicity against HIV proteins (Gag, Tat, Pol, and Env), over time, and relating it to clinical progression and viral activity. Autologous EBV cell lines infected with vaccinia-HIV constructs were used as target cells, and bulk-cultured peripheral blood mononuclear cells as effector cells. The children ranged in age from 0 to 93 months, with six of the nine showing CTL activity to one or more HIV proteins. The specificity of the response was directed against Tat in the younger children, switching to Pol, then Gag or Env. Preliminary analysis of virological data showed no association between CTL and virus activity. The children with CTLs tended to be well clinically, but the cohort needs to be studied longer before conclusions can be made about CTL activity and HIV disease progression. Cytotoxic T lymphocyte activity has also been observed in two children diagnosed as HIV uninfected. These results show the importance of looking at CTL specificity, and may have implications in vaccine design.

  15. Determination and prevention of cytotoxic effects induced in human lymphocytes by the alkylating agent 2,2`-dichlorodiethyl sulfide (sulfur mustard, HD). (Reannouncement with new availability information)

    Energy Technology Data Exchange (ETDEWEB)

    Meier, H.L.; Johnson, J.B.


    2,2`-Dichlorodiethyl sulfide (sulfur mustard), HD, 1,1`thiobis(2-chloroethane) is a potent vesicant which can cause severe lesions to skin, lung, and eyes. There is no convenient in vitro or in vivo method(s) to objectively measure the damage induced by HD; therefore, a simple in vitro method was developed using human peripheral lymphocytes to study HD-induced cytotoxicity. The cytotoxicity of HD was measured using dye exclusion as an indicator of human lymphocyte viability. Exposure to HD resulted in both a time- and a concentration-dependent cytotoxic effect on human lymphocytes. Using this in vitro assay, the effectiveness of various therapeutics (niacin, niacinamide, and 3-aminobenzamide) in preventing HD-induced cytotoxicity was studied. Niacinamide and 3-aminobenzamide prevented the cytotoxic effects of HD for up to 2 days.

  16. Common antiviral cytotoxic t-lymphocyte epitope for diverse arenaviruses. (United States)

    Oldstone, M B; Lewicki, H; Homann, D; Nguyen, C; Julien, S; Gairin, J E


    Members of the Arenaviridae family have been isolated from mammalian hosts in disparate geographic locations, leading to their grouping as Old World types (i.e., lymphocytic choriomeningitis virus [LCMV], Lassa fever virus [LFV], Mopeia virus, and Mobala virus) and New World types (i.e., Junin, Machupo, Tacaribe, and Sabia viruses) (C. J. Peters, M. J. Buchmeier, P. E. Rollin, and T. G. Ksiazek, p. 1521-1551, in B. N. Fields, D. M. Knipe, and P. M. Howley [ed.], Fields virology, 3rd ed., 1996; P. J. Southern, p. 1505-1519, in B. N. Fields, D. M. Knipe, and P. M. Howley [ed.], Fields virology, 3rd ed., 1996). Several types in both groups-LFV, Junin, Machupo, and Sabia viruses-cause severe and often lethal human diseases. By sequence comparison, we noted that eight Old World and New World arenaviruses share several amino acids with the nucleoprotein (NP) that consists of amino acids (aa) 118 to 126 (NP 118-126) (RPQASGVYM) of LCMV that comprise the immunodominant cytotoxic T-lymphocyte (CTL) epitope for H-2(d) mice (32). This L(d)-restricted epitope constituted >97% of the total bulk CTLs produced in the specific antiviral or clonal responses of H-2(d) BALB mice. NP 118-126 of the Old World arenaviruses LFV, Mopeia virus, and LCMV and the New World arenavirus Sabia virus bound at high affinity to L(d). The primary H-2(d) CTL anti-LCMV response as well as that of a CTL clone responsive to LCMV NP 118-126 recognized target cells coated with NP 118-126 peptides derived from LCMV, LFV, and Mopeia virus but not Sabia virus, indicating that a common functional NP epitope exists among Old World arenaviruses. Use of site-specific amino acid exchanges in the NP CTL epitope among these arenaviruses identified amino acids involved in major histocompatibility complex binding and CTL recognition.

  17. Proteolytically modified human beta 2-microglobulin augments the specific cytotoxic activity in murine mixed lymphocyte culture

    DEFF Research Database (Denmark)

    Nissen, Mogens Holst; Claësson, M H


    (M-beta 2-m) bind to murine lymphocytes expressing H-2 class I antigens; M-beta 2-m, when added at day 0 and 1 of culture in nanomolar concentrations to a one-way murine allogeneic mixed lymphocyte culture (MLC) augments the generation of specific cytotoxic T lymphocytes; M-beta 2-m increases...... the endogenous production of interleukin 2 in the MLC culture; monoclonal antibody which reacts with both the native beta 2-m and M-beta 2-m molecule blocks the augmentation of cytotoxic T lymphocyte production induced by M-beta 2-m; murine as well as human MLC responder cells can proteolytically modify native...

  18. Cytotoxic T lymphocyte responses against melanocytes and melanoma

    Directory of Open Access Journals (Sweden)

    Schwartz Erich J


    Full Text Available Abstract Background Vitiligo is a common toxicity associated with immunotherapy for melanoma. Cytotoxic T lymphocytes (CTLs against melanoma commonly target melanoma-associated antigens (MAAs which are also expressed by melanocytes. To uncouple vitiligo from melanoma destruction, it is important to understand if CTLs can respond against melanoma and melanocytes at different levels. Methods To understand the dichotomous role of MAA-specific CTL, we characterized the functional reactivities of established CTL clones directed to MAAs against melanoma and melanocyte cell lines. Results CTL clones generated from melanoma patients were capable of eliciting MHC-restricted, MAA-specific lysis against melanocyte cell lines as well as melanoma cells. Among the tested HLA-A*0201-restricted CTL clones, melanocytes evoked equal to slightly higher degranulation and cytolytic responses as compared to melanoma cells. Moreover, MAA-specific T cells from vaccinated patients responded directly ex vivo to melanoma and melanocytes. Melanoma cells express slightly higher levels of MART-1 and gp100 than melanocytes as measured by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR and immunohistochemistry. Conclusions Our data suggest that CTLs respond to melanoma and melanocytes equally in vitro and directly ex vivo.

  19. Assessment of cytotoxic and apoptotic effects of benzaldehyde using different assays. (United States)

    Ulker, Z; Alpsoy, L; Mihmanli, A


    Benzaldehyde (BA) occurs naturally in a number of plants, including cherry, fig and peach fruit and carnation flowers at therapeutic doses. In addition, it is used in cosmetics, personal care products and food as a preservative. In this study, we aimed to determine the cytotoxic and apoptotic effects of different concentrations of BA on cultured human lymphocytes using lactate dehydrogenase assay, cell proliferation (water-soluble tetrazolium salts-1) assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) test (apoptotic test) as a group of cytotoxicity tests at 6th and 24th h on human lymphocyte cell culture. The cytotoxicity increased when cells were treated with 10, 25 and 50 μg/mL concentrations of BA (p < 0.05). Moreover, treatment of the cells with the same concentrations significantly decreased the cell number at the 6th and 24th hours (p < 0.05). TUNEL assay results also show that the concentration of BA at 10, 25 and 50 μg/mL caused DNA damage significantly (p < 0.05). According to our results, the toxic and genotoxic effects of BA have to be further evaluated before using in cosmetic and food products.

  20. The Granzyme B ELISPOT assay: an alternative to the 51Cr-release assay for monitoring cell-mediated cytotoxicity

    Directory of Open Access Journals (Sweden)

    Baseler Michael


    Full Text Available Abstract Background The interferon-γ (IFN-γ ELISPOT assay is one of the most useful techniques for immunological monitoring of cancer vaccine trials and has gained increased application as a measure of specific T cell activation. However, it does not assess cell-mediated cytotoxicity directly as IFN-γ secretion is not limited to only cytolytic cells. Granzyme B (GrB is a key mediator of target cell death via the granule-mediated pathway. Therefore, the release of GrB by cytolytic lymphocytes upon effector-target interaction may be a more specific indicator of CTL and NK cytotoxic ability than IFN-γ secretion. Methods We assessed whether the GrB ELISPOT assay is a viable alternative to the 51Cr-release and IFN-γ ELISPOT assays for measuring antigen-specific CTL cytotoxicity. Direct comparisons between the three assays were made using human CTL cell lines (αEN-EBV and αJY and an in vitro stimulated anti-Flu matrix peptide (FMP-specific CTL. Results When the GrB ELISPOT was directly compared to the IFN-γ ELISPOT and 51Cr-release assays, excellent cross-correlation between all three assays was shown. However, measurable IFN-γ secretion in the ELISPOT assay was observed only after 1 hour of incubation and cytotoxicity assessed via the 51Cr-release assay after 4 hours, whereas GrB secretion was detectable within 10 min of effector-target contact with significant secretion observed after 1 h. Titration studies demonstrated a strong correlation between the number of effector cells and GrB spots per well. Irrelevant targets or antigens did not induce significant GrB secretion. Additionally, GrB secretion was abrogated when CTL cultures were depleted of CD8+ cells. Conclusion Our findings demonstrate that the GrB ELISPOT assay is a superior alternative to the 51Cr-release assay since it is significantly more sensitive and provides an estimation of cytotoxic effector cell frequency. Additionally, unlike the IFN-γ ELISPOT assay, the GrB ELISPOT

  1. Synergistic Cytotoxicity of Melatonin and New-generation Anticancer Drugs Against Leukemia Lymphocytes But Not Normal Lymphocytes. (United States)

    Zhelev, Zhivko; Ivanova, Donika; Bakalova, Rumiana; Aoki, Ichio; Higashi, Tatsuya


    The present study demonstrates specific sensitization of leukemia lymphocytes towards anticancer drugs using melatonin and clarifies the role of reactive oxygen species (ROS) for induction of apoptosis. The study covers four conventional and 11 new-generation anticancer drugs. Four parameters were analyzed simultaneously in leukemia and normal lymphocytes treated with drug, melatonin, or their combination: cell viability, induction of apoptosis, level of reactive oxygen species (ROS), and level of protein-carbonyl products. Almost all investigated combinations of melatonin with new-generation anticancer drugs were characterized by synergistic cytotoxicity towards leukemia lymphocytes, while the combinations with conventional drugs exhibited additive or antagonistic effects on cell viability. In leukemia lymphocytes, the additive cytotoxicity of doxorubicin plus melatonin was accompanied by low levels of ROS and protein-carbonyl products, as well as by suppression of apoptosis. In normal lymphocytes, none of the studied parameters changed significantly compared to cells treated with doxorubicin only. The combinations of everolimus plus melatonin and barasertib plus melatonin exhibited impressive synergistic cytotoxic effects on leukemia lymphocytes but did not affect the viability of normal lymphocytes. In leukemia cells, the synergistic cytotoxicity was accompanied by strong induction of apoptosis but a decrease of ROS to a level below that of the control. In normal lymphocytes, these combinations did not affect the level of ROS nor of protein-carbonyl products, and did not induce apoptosis. The data suggest that melatonin is a promising supplementary component in chemotherapy which allows the therapeutic doses of anticancer drugs to be reduced, minimizing their side-effects.

  2. Cytotoxicity of lymphocytes from melanoma patients against autologous tumor cells and its potentiation in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Bykovskaya, S.N.; Iobadze, M.S.; Kupriyanova, T.A.; Demidov, L.V.


    The specific and natural cytotoxicity of peripheral blood lymphocytes from patients with melanomas was compared and stimulation with autologous tumor cells or a pool of allogeneic lymphocytes from five healthy blood donors also was used to potentiate the specific antitumor activity of the patients' lymphocytes. To assess cytolytic ability, cells of an autologous tumor, cells of the K-562 line, autologous peripheral blood lymphocytes, and blast cells obtained from these lymphocytes after stimulation by phytohemagglutinin were used as the target cells. The target cells were incubated in a medium containing sodium chromate and were labelled with the chromium 51 isotope.

  3. Development of a serum-free medium for in vitro expansion of human cytotoxic T lymphocytes using a statistical design

    Directory of Open Access Journals (Sweden)

    Lee Gyun


    Full Text Available Abstract Background Serum-containing medium (SCM, which has a number of poorly defined components with varying concentrations, hampers standardization of lymphocyte cultures. In order to develop a serum-free medium (SFM for the expansion of human lymphocytes from peripheral blood mononuclear cells (PBMCs, a statistical optimization approach based on a fractional factorial method and a response surface method was adopted. A basal medium was prepared by supplementing RPMI1640 medium with insulin, albumin, ferric citrate, ethanolamine, fatty acids, glutamine, sodium pyruvate, 2-mercaptoethanol, 1-thioglycerol, nonessential amino acids, and vitamins. We identified additional positive determinants and their optimal concentrations for cell growth through a statistical analysis. Results From a statistical analysis using the fractional factorial method, cholesterol and polyamine supplement were identified as positive determinants for cell growth. Their optimal concentrations were determined by the response surface method. The maximum viable cell concentration in the developed SFM was enhanced by more than 1.5-fold when compared to that in RPMI1640 supplemented with 10% fetal bovine serum (FBS. Furthermore, a cytotoxicity assay and an enzyme-linked immunospot assay revealed that the effector function of cytotoxic T lymphocytes generated from PBMCs grown in SFM, by stimulation of peptide-presenting dendritic cells, was retained or even better than that in SCM. Conclusions The use of a developed SFM with cholesterol and polyamine supplement for human lymphocyte culture resulted in better growth without loss of cellular function when compared to SCM.

  4. Correlation between luminescence intensity and cytotoxicity in cell-based cytotoxicity assay using luciferase. (United States)

    Wakuri, S; Yamakage, K; Kazuki, Y; Kazuki, K; Oshimura, M; Aburatani, S; Yasunaga, M; Nakajima, Y


    The luciferase reporter assay has become one of the conventional methods for cytotoxicity evaluation. Typically, the decrease of luminescence expressed by a constitutive promoter is used as an index of cytotoxicity. However, to our knowledge, there have been no reports of the correlation between cytotoxicity and luminescence intensity. In this study, to accurately verify the correlation between them, beetle luciferase was stably expressed in human hepatoma HepG2 cells harboring the multi-integrase mouse artificial chromosome vector. We showed that the cytotoxicity assay using luciferase does not depend on the stability of luciferase protein and the kind of constitutive promoter. Next, HepG2 cells in which green-emitting beetle luciferase was expressed under the control of CAG promoter were exposed to 58 compounds. The luminescence intensity and cytotoxicity curves of cells exposed to 48 compounds showed similar tendencies, whereas those of cells exposed to 10 compounds did not do so, although the curves gradually approached each other with increasing exposure time. Finally, we demonstrated that luciferase expressed under the control of a constitutive promoter can be utilized both as an internal control reporter for normalizing a test reporter and for monitoring cytotoxicity when two kinds of luciferases are simultaneously used in the cytotoxicity assay. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Anti-cytotoxic T lymphocyte antigen-4 antibodies in melanoma

    Directory of Open Access Journals (Sweden)

    Tosti G


    Full Text Available Giulio Tosti, Emilia Cocorocchio, Elisabetta PennacchioliDivisione Melanomi e Sarcomi, Istituto Europeo di Oncologia, Milano, ItalyAbstract: Approaches aimed at enhancement of the tumor specific response have provided proof for the rationale of immunotherapy in cancer, both in animal models and in humans. Ipilimumab, an anti-cytotoxic T lymphocyte antigen-4 (CTLA-4 antibody, is a new generation immunotherapeutic agent that has shown activity in terms of disease free and overall survival in metastatic melanoma patients. Its use was approved by the US Food and Drug Administration in March 2011 to treat patients with late stage melanoma that has spread or that cannot be removed by surgery. The mechanism of action of CTLA-4 antibodies in the activation of an antitumor immune response and selected clinical studies of ipilimumab in advanced melanoma patients are discussed. Ipilimumab treatment has been associated with immune related adverse events due to T-cell activation and proliferation. Most of these serious adverse effects are associated with the gastrointestinal tract and include severe diarrhea and colitis. The relationship between immune related adverse events and antitumor activity associated with ipilimumab was explored in clinical studies. Potential biomarkers predictive for clinical response and survival in patients treated with anti-CTLA-4 therapy are presently under investigation. Besides the conventional patterns of response and stable disease as defined by standard Response Evaluation Criteria in Solid Tumors criteria, in subsets of patients, ipilimumab has shown patterns of delayed clinical activity which were associated with an improved overall survival. For this reason a new set of response criteria for tumor immunotherapy has been proposed, which was termed immune related response criteria. These new criteria are presently used to better analyze clinical activity of immunotherapeutic regimens. Ipilimumab is currently under

  6. The kinematics of cytotoxic lymphocytes influence their ability to kill target cells. (United States)

    Bhat, Purnima; Leggatt, Graham; Matthaei, Klaus I; Frazer, Ian H


    Cytotoxic lymphocytes (CTL) have been reported to show a range of motility patterns from rapid long-range tracking to complete arrest, but how and whether these kinematics affect their ability to kill target cells is not known. Many in vitro killing assays utilize cell lines and tumour-derived cells as targets, which may be of limited relevance to the kinetics of CTL-mediated killing of somatic cells. Here, live-cell microscopy is used to examine the interactions of CTL and primary murine skin cells presenting antigens. We developed a qualitative and quantitative killing assay using extended-duration fluorescence time-lapse microscopy coupled with large-volume objective software-based data analysis to obtain population data of cell-to-cell interactions, motility and apoptosis. In vivo and ex vivo activated antigen-specific cytotoxic lymphocytes were added to primary keratinocyte targets in culture with fluorometric detection of caspase-3 activation in targets as an objective determinant of apoptosis. We found that activated CTL achieved contact-dependent apoptosis of non-tumour targets after a period of prolonged attachment - on average 21 hours - which was determined by target cell type, amount of antigen, and activation status of CTL. Activation of CTL even without engagement of the T cell receptor was sufficient to mobilise cells significantly above baseline, while the addition of cognate antigen further enhanced their motility. Highly activated CTL showed markedly increased vector displacement, and velocity, and lead to increased antigen-specific target cell death. These data show that the inherent kinematics of CTL correlate directly with their ability to kill non-tumour cells presenting cognate antigen.

  7. The kinematics of cytotoxic lymphocytes influence their ability to kill target cells.

    Directory of Open Access Journals (Sweden)

    Purnima Bhat

    Full Text Available Cytotoxic lymphocytes (CTL have been reported to show a range of motility patterns from rapid long-range tracking to complete arrest, but how and whether these kinematics affect their ability to kill target cells is not known. Many in vitro killing assays utilize cell lines and tumour-derived cells as targets, which may be of limited relevance to the kinetics of CTL-mediated killing of somatic cells. Here, live-cell microscopy is used to examine the interactions of CTL and primary murine skin cells presenting antigens. We developed a qualitative and quantitative killing assay using extended-duration fluorescence time-lapse microscopy coupled with large-volume objective software-based data analysis to obtain population data of cell-to-cell interactions, motility and apoptosis. In vivo and ex vivo activated antigen-specific cytotoxic lymphocytes were added to primary keratinocyte targets in culture with fluorometric detection of caspase-3 activation in targets as an objective determinant of apoptosis. We found that activated CTL achieved contact-dependent apoptosis of non-tumour targets after a period of prolonged attachment - on average 21 hours - which was determined by target cell type, amount of antigen, and activation status of CTL. Activation of CTL even without engagement of the T cell receptor was sufficient to mobilise cells significantly above baseline, while the addition of cognate antigen further enhanced their motility. Highly activated CTL showed markedly increased vector displacement, and velocity, and lead to increased antigen-specific target cell death. These data show that the inherent kinematics of CTL correlate directly with their ability to kill non-tumour cells presenting cognate antigen.

  8. The Assessment of Cytotoxicity and Genotoxicity of Mirtazapine in Human Blood Lymphocytes Using Micronucleus Test

    Directory of Open Access Journals (Sweden)

    M Norizadeh tazehkand


    Results: MN formation was not significantly induced at 24- and 48-h treatment periods when compared with control but Nuclear division index (NDI significantly decreased at all concentrations for two treatment periods. Conclusion: Mirtazapine was not genetoxic but was cytotoxic in human peripheral blood lymphocytes. According to this study mirtazapine has cytotoxic effects on human's cells.

  9. Real time assays for quantifying cytotoxicity with single cell resolution.

    Directory of Open Access Journals (Sweden)

    Sonny C Hsiao

    Full Text Available A new live cell-based assay platform has been developed for the determination of complement dependent cytotoxicity (CDC, antibody dependent cellular cytotoxicity (ADCC, and overall cytotoxicity in human whole blood. In these assays, the targeted tumor cell populations are first labeled with fluorescent Cell Tracker dyes and immobilized using a DNA-based adhesion technique. This allows the facile generation of live cell arrays that are arranged arbitrarily or in ordered rectilinear patterns. Following the addition of antibodies in combination with serum, PBMCs, or whole blood, cell death within the targeted population can be assessed by the addition of propidium iodide (PI as a viability probe. The array is then analyzed with an automated microscopic imager. The extent of cytotoxicity can be quantified accurately by comparing the number of surviving target cells to the number of dead cells labeled with both Cell Tracker and PI. Excellent batch-to-batch reproducibility has been achieved using this method. In addition to allowing cytotoxicity analysis to be conducted in real time on a single cell basis, this new assay overcomes the need for hazardous radiochemicals. Fluorescently-labeled antibodies can be used to identify individual cells that bear the targeted receptors, but yet resist the CDC and ADCC mechanisms. This new approach also allows the use of whole blood in cytotoxicity assays, providing an assessment of antibody efficacy in a highly relevant biological mixture. Given the rapid development of new antibody-based therapeutic agents, this convenient assay platform is well-poised to streamline the drug discovery process significantly.

  10. Cytotoxicity assays to evaluate tannery effluents treated by photoelectrooxidation

    Directory of Open Access Journals (Sweden)

    N. Jaeger

    Full Text Available The advanced oxidation process (AOP is used to increase the treatment efficiency of effluents however, it is necessary to compare the toxicity of treated and untreated effluents to evaluate if the decontamination process does not cause any biological harm. Cultured cells have been previously used to assess the genotoxic and cytotoxic potential of various compounds. Hence, the aim of this work was to assess the applicability of cytotoxicity assays to evaluate the toxicity related to the AOP treatment. Samples of an industrial effluent were collected after their treatment by a conventional method. Cytotoxicity of standard and AOP treated effluents was assessed in CRIB and HEp-2 cell line using the MTT and neutral red assays. We observed decrease at cell viability in the both assays (50% MTT and 13% NRU when cells were exposed to the AOP treatment in the highest concentration. Thus, cytotoxic assays in cultured cells can be explored as an useful method to evaluate toxicity as well as to optimize effluents treatment process.

  11. Lactate dehydrogenase assay for assessment of polycation cytotoxicity

    DEFF Research Database (Denmark)

    Parhamifar, Ladan; Andersen, Helene; Moghimi, Seyed Moien


    cannot stand alone in determining the type and extent of damage or cell death mechanism. In this chapter we describe a lactate dehydrogenase (LDH) assay for high-throughput screening that can be used as a starting point for further detailed cytotoxicity determination. LDH release is considered an early...

  12. Genotoxic and cytotoxic effects of Sunset Yellow and Brilliant Blue, colorant food additives, on human blood lymphocytes. (United States)

    Kus, Esra; Eroglu, Halil Erhan


    The synthetic dyes over fifty are used in many areas including the food industry around the world. Sunset Yellow FCF and Brilliant Blue FCF are used as colorant food additives in many food products. The present study investigated the genotoxic and cytotoxic effects of Sunset Yellow and Brilliant Blue. Genotoxic and cytotoxic activities of the food additives were evaluated in lymphocyte cell cultures using mitotic index, replication index and micronucleus assay. Mitotic index frequencies and replication index values were decreased and micronucleus frequency was increased with increasing concentrations of Sunset Yellow and Brilliant Blue. The changes in mitotic index and micronucleus are statistically significant (pBlue can have cytotoxic and genotoxic potential. It care must be taken when using these materials as a food additive.

  13. Regulatory effect of Ganoderma lucidum polysaccharides on cytotoxic T-lymphocytes induced by dendritic cells in vitro

    Institute of Scientific and Technical Information of China (English)

    CAOLi-Zhen; LINZhi-Bin


    AIM:To study the regulatory effects of Ganoderma lucidum polysaccharides(Gl-PS)on cytotoxicity and mechanism of specific cytotoxic T-lymphocytes(CTL)induced by dendritic cells(DC)in vitro during the stage of antigen presentation.METHODS:Cultured murine bone marrow-derived DC were pulsed with P815 tumor cell lysates and co-incubated with or without various concentrations of Gl-PS(0.8,3.2,or 12.8mg/L)at the same time.P815 specific CTL were induced by spleen lymphocytes stimulated with mature DC.Non-adherent cells and culture supernatants were harvested on d 5 for analysis of specific cytotoxicity with lactate dehydrogenase(LDH)activity assay,mRNA expression of IFNγ,granzyme B with RT-PCR assay,and protein expression of IFNγ,granzyme B with ELISA or Western blot assay,respectively,RESULTS:Three concentrations of Gl-PS promoted LDH activities released into culture supernatants(P<0.01).It also increased mRNA expression of IFNγin CTL(Gl-PS 12.8mg/L vs RPMI medium 1640,P<0.05)and granzyme B in CTL(P<0.01).Protein production of IFNγin culture supernatants(P<0.05)and protein expression of granzyme B in CTL(Gl-PS 12.8mg/L vs RPMI medium 1640,P<0.05)were also augmented by Gl-PS,CONCLUSION:Gl-PS is shown to promote the cytotoxicity of specific CTL induced by DC which were pulsed with P815 tumor antigen during the stage of antigen presentation,and the mechanism of cytotoxicity is believed to be going through IFNγ and granzyme B pathways.

  14. The imbalance of helper T lymphocytes and cytotoxic T lymphocytes in acute renal transplantation rejection

    Institute of Scientific and Technical Information of China (English)



    To investigate the imbalance state of helper T lymphocytes (Th) and cytotoxic T lymphocytes (Tc) and the roles of Th1/Th2/Th3 and Tc1/Tc2 cells in renal transplantation rejection, the percentages of these cells in peripheral blood of 24 cases of renal transplantation recipients with acute rejection and the dynamic changes of the CD4/CD8 ratio were determined by flow cytometry analysis,while 30 cases of healthy individuals were set up as controls. In these healthy controls, the percentages of the Th1, Th2 and Th3 cells were (10.45±8.15)%, (5.05±4.15)% and (3.90±3.21)%,and those of Tc1 and Tc2 cells were (9.83±7.03)% and (4.51±2.17)%, respectively. However,the percentages of Th1 and Tc1 cells in peripheral blood of the stable recipients after transplantation were (7.29±5.62)% and (7.04±5.15)%, showing definite reduction, while those of Th2, Th3and Tc2 cells showed significant increase, (6.34±5.67)%, (4.94±4.14) % and ( 6.86 ±4.42) %, respectively. In case of recipients with acute rejection, the percentages of Th1 and Tc1 cells appeared to be (18.55±13.21)% and (15.84±11.72)%, also showing significant increase, but those of Th2,Th3 and Tc2 cells appeared to be reduced, (4.19±3.62)%, (3.02±2.83)% and (3.88±1.63) %, respectively. Significant differences could be detected among these three groups (P <0.05). The CD4/CD8 ratio in cases with acute rejection was higher than those of stable recipients (2.24±0.59 vs 1.95±0.45), but that of the stable recipients and healthy controls (1.98±0.31 )showed no any significant difference. From the above observation, it is evident that imbalance between Th1, Th2 and Th3 with Te1 and Tc2 cells may exist after renal transplantation and probably, the immune imbalance may be induced through the secretion of cytokines INF-γ by Th1 or Te1 cells , I1-4 by Th2 and Tc2 cells and TGF-β by Th3.

  15. CRTAM determines the CD4+ cytotoxic T lymphocyte lineage. (United States)

    Takeuchi, Arata; Badr, Mohamed El Sherif Gadelhaq; Miyauchi, Kosuke; Ishihara, Chitose; Onishi, Reiko; Guo, Zijin; Sasaki, Yoshiteru; Ike, Hiroshi; Takumi, Akiko; Tsuji, Noriko M; Murakami, Yoshinori; Katakai, Tomoya; Kubo, Masato; Saito, Takashi


    Naive T cells differentiate into various effector T cells, including CD4(+) helper T cell subsets and CD8(+) cytotoxic T cells (CTL). Although cytotoxic CD4(+) T cells (CD4 +: CTL) also develop from naive T cells, the mechanism of development is elusive. We found that a small fraction of CD4(+) T cells that express class I-restricted T cell-associated molecule (CRTAM) upon activation possesses the characteristics of both CD4(+) and CD8(+) T cells. CRTAM(+) CD4(+) T cells secrete IFN-γ, express CTL-related genes, such as eomesodermin (Eomes), Granzyme B, and perforin, after cultivation, and exhibit cytotoxic function, suggesting that CRTAM(+) T cells are the precursor of CD4(+)CTL. Indeed, ectopic expression of CRTAM in T cells induced the production of IFN-γ, expression of CTL-related genes, and cytotoxic activity. The induction of CD4(+)CTL and IFN-γ production requires CRTAM-mediated intracellular signaling. CRTAM(+) T cells traffic to mucosal tissues and inflammatory sites and developed into CD4(+)CTL, which are involved in mediating protection against infection as well as inducing inflammatory response, depending on the circumstances, through IFN-γ secretion and cytotoxic activity. These results reveal that CRTAM is critical to instruct the differentiation of CD4(+)CTL through the induction of Eomes and CTL-related gene.

  16. Fatal meningitis following lymphocytic choriomeningitis virus infection reflects delayed-type hypersensitivity rather than cytotoxicity

    DEFF Research Database (Denmark)

    Thomsen, Allan Randrup; Bro-Jørgensen, K; Volkert, M


    Fatal meningitis following intracerebral inoculation of lymphocytic choriomeningitis virus (LCMV) reflects an immunopathological lesion believed to be mediated by cytotoxic T cells. The results presented here demonstrate that pretreatment with cyclophosphamide (Cy; 150 mg/kg body weight) 2 days...... before intracerebral infection significantly reduced the lethality of the infection. However, this treatment did not impair the antiviral cytotoxic response as measured in the spleen. On the other hand, virus-specific delayed-type hypersensitivity (DTH) was significantly reduced. This reduction seems...... not solely represent T-cell-mediated cytotoxicity in vivo but that a fatal outcome of the infection critically involves not only effector T cells but also ancillary cells....

  17. Pattern of CD4 T‑lymphocyte Values in Cancer Patients on Cytotoxic ...

    African Journals Online (AJOL)

    Annals of Medical and Health Sciences Research ... Pattern of CD4 T‑lymphocyte Values in Cancer Patients on Cytotoxic Therapy ... They were adult patients who had been diagnosed with breast cancer 36/80 cases (45%), non‑Hodgkin's ...

  18. Peptide microarrays for the profiling of cytotoxic T-lymphocyte activity using minimum numbers of cells.

    NARCIS (Netherlands)

    Hoff, A.; Bagu, A.C.; Andre, T.; Roth, G.; Wiesmuller, K.H.; Guckel, B.; Brock, R.E.


    The identification of epitopes that elicit cytotoxic T-lymphocyte activity is a prerequisite for the development of cancer-specific immunotherapies. However, especially the parallel characterization of several epitopes is limited by the availability of T cells. Microarrays have enabled an unpreceden

  19. Neuroinflammation by cytotoxic T-lymphocytes impairs retrograde axonal transport in an oligodendrocyte mutant mouse.

    Directory of Open Access Journals (Sweden)

    Chi Wang Ip

    Full Text Available Mice overexpressing proteolipid protein (PLP develop a leukodystrophy-like disease involving cytotoxic, CD8+ T-lymphocytes. Here we show that these cytotoxic T-lymphocytes perturb retrograde axonal transport. Using fluorogold stereotactically injected into the colliculus superior, we found that PLP overexpression in oligodendrocytes led to significantly reduced retrograde axonal transport in retina ganglion cell axons. We also observed an accumulation of mitochondria in the juxtaparanodal axonal swellings, indicative for a disturbed axonal transport. PLP overexpression in the absence of T-lymphocytes rescued retrograde axonal transport defects and abolished axonal swellings. Bone marrow transfer from wildtype mice, but not from perforin- or granzyme B-deficient mutants, into lymphocyte-deficient PLP mutant mice led again to impaired axonal transport and the formation of axonal swellings, which are predominantly located at the juxtaparanodal region. This demonstrates that the adaptive immune system, including cytotoxic T-lymphocytes which release perforin and granzyme B, are necessary to perturb axonal integrity in the PLP-transgenic disease model. Based on our observations, so far not attended molecular and cellular players belonging to the immune system should be considered to understand pathogenesis in inherited myelin disorders with progressive axonal damage.

  20. Role of interferon-γ and cytotoxic T lymphocytes in intraocular tumor rejection. (United States)

    Ligocki, Ann J; Brown, Joseph R; Niederkorn, Jerry Y


    The eye is normally an immunosuppressive environment. This condition is better known as immune privilege and protects the eye from immune-mediated inflammation of tissues that cannot regenerate. However, immune privilege creates a dilemma for the eye when intraocular neoplasms arise. In some cases, immune privilege is suspended, resulting in the immune rejection of intraocular tumors. This study employed a mouse model in which interferon-γ-dependent intraocular tumor rejection occurs. We tested the hypothesis that this rejection requires interferon-γ for the generation and functional capacity of cytotoxic T lymphocyte-mediated rejection of intraocular tumors. Tumors grew progressively in the eyes of interferon-γ knockout mice, even though the mice generated tumor-specific cytotoxic T lymphocyte responses in the periphery. However, interferon-γ knockout mice rejected tumors that were introduced into extraocular sites. Subcutaneous tumor immunization before intraocular challenge led to tumor rejection and preservation of the eye in wild-type mice. By contrast, tumors grew progressively in the eyes of interferon-γ knockout mice despite their ability to generate peripheral tumor-specific cytotoxic T lymphocytes as well as the capacity of CD8(+) T cells to enter the eye as shown by the presence of CD8 and perforin message and CD3(+)CD8(+) leukocytes within the tumor-bearing eye. We found that cytotoxic T lymphocytes generated in wild-type mice and adoptively transferred into interferon-γ knockout mice mediated the rejection of intraocular tumors in interferon-γ knockout hosts. The results indicate that interferon-γ is critical for the initial priming and differentiation of cytotoxic T lymphocytes residing in the periphery to produce the most effect antitumor function within the eye.

  1. Structural Basis for Degenerate Recognition of Natural HIV Peptide Variants by Cytotoxic Lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Hackert,E.; Anikeeva, N.; Kalams, S.; Walker, B.; Hendrickson, W.; Sykulev, Y.


    It is well established that even small changes in amino acid side chains of antigenic peptide bound to MHC protein may completely abrogate recognition of the peptide-MHC (pMHC) complex by the T-cell receptor (TCR). Often, however, several non-conservative substitutions in the peptide antigen are accommodated and do not impair its recognition by TCR. For example, a preponderance of natural sequence variants of the HIV p17 Gag-derived peptide SLYNTVATL (SL9) are recognized by cytotoxic T lymphocytes (CTL), which implies that interactions with SL9 variants are degenerate both with respect to the class I MHC molecule and with respect to TCR. Here we study the molecular basis for this degenerate recognition of SL9 variants. We show that several SL9 variants bind comparably well to soluble HLA-A2 and to a particular soluble TCR and that these variants are active in the cognate cytotoxicity assay. Natural SL9 variation is restricted by its context in the HIV p17 matrix protein, and we have used synthetic variants to explore the wider spectrum of recognition. High-resolution crystal structures of seven selected SL9 variants bound to HLA-A2 all have remarkably similar peptide conformations and side-chain dispositions outside sites of substitution. This preservation of the peptide conformation despite epitope variations suggests a mechanism for the observed degeneracy in pMHC recognition by TCR, and may contribute to the persistence of SL9-mediated immune responses in chronically infected individuals.

  2. Cytotoxic T-lymphocyte-mediated killing of human pancreatic islet cells in vitro. (United States)

    Campbell, Peter D; Estella, Eugene; Dudek, Nadine L; Jhala, Gaurang; Thomas, Helen E; Kay, Thomas W H; Mannering, Stuart I


    Cytotoxic T lymphocytes (CTL) are believed to play an essential role in beta-cell destruction leading to development of type 1 diabetes and allogeneic islet graft failure. We aimed to identify the mechanisms used by CTL to kill human beta cells. CTL clones that recognize epitopes from influenza virus and Epstein-Barr virus restricted by human leukocyte antigen (HLA)-A0201 and -B0801, respectively, were used to investigate the susceptibility of human beta cells to CTL. In a short-term (5-hour) assay, CTL killed human islet cells of the appropriate major histocompatibility complex (MHC) class I type that had been pulsed with viral peptides. Killing was increased by pretreating islets with interferon gamma that increases MHC class I on target cells. Killing was abolished by incubation of CTL with the perforin inhibitor concanamycin A. The Fas pathway did not contribute to killing because blocking with neutralizing anti-Fas ligand antibody did not significantly reduce beta-cell killing. In conclusion, we report a novel way of investigating the interaction between CTL and human islets. Human islets were rapidly killed in vitro by MHC class I-restricted CTL predominantly by the granule exocytosis pathway.

  3. HLA-G inhibits xenogenetic cytotoxicity mediated by human NK cells and T lymphocytes against PECs

    Institute of Scientific and Technical Information of China (English)


    In order to investigate whether the non-classi-cal HLA-G classⅠmolecule protects the porcine endothelial cells (PECs) from the lysis mediated by human immune cells in pig to human discordant xenotransplantation, we have cloned HLA-G cDNA from a human placenta by RT-PCR. Mammalian expression vector, pEFG-neo, was constructed by insertion of HLA-G cDNA in pEF-neo. We obtained efficiently expressed PECs by stable transfection. Cytotoxicity assay showed that overexpression of HLA-G on PECs was sufficient to inhibit human NK-92 cell lysis. The level of lysis was equal to or less than that of the lysis of human umbilical vein endothelial cells mediated by human NK-92 cells. It also indicated that HLA-G inhibited the lysis of PECs mediated by xeno-antigen specific T lymphocytes. The reduction of lysis ranged between 59.1% and 88.9%. These findings suggest that the transgenic approach to overexpress HLA-G is believed to be a new immunotherapy in overcoming the immune rejections in xenotransplantion, including delayed xenograft rejection and cell-mediated rejection.

  4. Cell-mediated immunity to Plasmodium falciparum infection: evidence against the involvement of cytotoxic lymphocytes

    DEFF Research Database (Denmark)

    Theander, T G; Andersen, B J; Pedersen, B K;


    by either SPag or PPD in the presence of immune serum. Studies on subpopulations of PBMC indicated that the inhibitory cells resided among the adherent cell fraction. Furthermore we tested PBMC for cytotoxic activity against P. falciparum-infected autologous or heterologous erythrocytes. Experiments were...... done both in the absence and the presence of immune serum. Neither fresh PBMC nor PBMC activated by SPag or PPD for 7 days prior to assay were cytotoxic, indicating that cytotoxic T cells, natural killer (NK) cells, and K cells did not possess cytotoxic activity directed against parasitized...

  5. A New Cytotoxicity Assay for Brevetoxins Using Fluorescence Microscopy

    Directory of Open Access Journals (Sweden)

    Jennifer R. McCall


    Full Text Available Brevetoxins are a family of ladder-framed polyether toxins produced during blooms of the marine dinoflagellate, Karenia brevis. Consumption of shellfish or finfish exposed to brevetoxins can lead to the development of neurotoxic shellfish poisoning. The toxic effects of brevetoxins are believed to be due to the activation of voltage-sensitive sodium channels in cell membranes. The traditional cytotoxicity assay for detection of brevetoxins uses the Neuro-2A cell line, which must first be treated with the neurotoxins, ouabain and veratridine, in order to become sensitive to brevetoxins. In this study, we demonstrate several drawbacks of the Neuro-2A assay, which include variability for the EC50 values for brevetoxin and non-linear triphasic dose response curves. Ouabain/ veratridine-treated Neuro-2A cells do not show a typical sigmoidal dose response curve in response to brevetoxin, but rather, have a polynomial shaped curve, which makes calculating EC50 values highly variable. We describe a new fluorescence live cell imaging model, which allows for accurate calculation of cytotoxicity via nuclear staining and additional measurement of other viability parameters depending on which aspect of the cell is stained. In addition, the SJCRH30 cell line shows promise as an alternative to Neuro-2A cells for testing brevetoxins without the need for ouabain and veratridine.

  6. Hantavirus-infection confers resistance to cytotoxic lymphocyte-mediated apoptosis.

    Directory of Open Access Journals (Sweden)

    Shawon Gupta


    Full Text Available Hantaviruses cause hemorrhagic fever with renal syndrome (HFRS and hantavirus cardio-pulmonary syndrome (HCPS; also called hantavirus pulmonary syndrome (HPS, both human diseases with high case-fatality rates. Endothelial cells are the main targets for hantaviruses. An intriguing observation in patients with HFRS and HCPS is that on one hand the virus infection leads to strong activation of CD8 T cells and NK cells, on the other hand no obvious destruction of infected endothelial cells is observed. Here, we provide an explanation for this dichotomy by showing that hantavirus-infected endothelial cells are protected from cytotoxic lymphocyte-mediated induction of apoptosis. When dissecting potential mechanisms behind this phenomenon, we discovered that the hantavirus nucleocapsid protein inhibits the enzymatic activity of both granzyme B and caspase 3. This provides a tentative explanation for the hantavirus-mediated block of cytotoxic granule-mediated apoptosis-induction, and hence the protection of infected cells from cytotoxic lymphocytes. These findings may explain why infected endothelial cells in hantavirus-infected patients are not destroyed by the strong cytotoxic lymphocyte response.

  7. Hantavirus-infection confers resistance to cytotoxic lymphocyte-mediated apoptosis. (United States)

    Gupta, Shawon; Braun, Monika; Tischler, Nicole D; Stoltz, Malin; Sundström, Karin B; Björkström, Niklas K; Ljunggren, Hans-Gustaf; Klingström, Jonas


    Hantaviruses cause hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardio-pulmonary syndrome (HCPS; also called hantavirus pulmonary syndrome (HPS)), both human diseases with high case-fatality rates. Endothelial cells are the main targets for hantaviruses. An intriguing observation in patients with HFRS and HCPS is that on one hand the virus infection leads to strong activation of CD8 T cells and NK cells, on the other hand no obvious destruction of infected endothelial cells is observed. Here, we provide an explanation for this dichotomy by showing that hantavirus-infected endothelial cells are protected from cytotoxic lymphocyte-mediated induction of apoptosis. When dissecting potential mechanisms behind this phenomenon, we discovered that the hantavirus nucleocapsid protein inhibits the enzymatic activity of both granzyme B and caspase 3. This provides a tentative explanation for the hantavirus-mediated block of cytotoxic granule-mediated apoptosis-induction, and hence the protection of infected cells from cytotoxic lymphocytes. These findings may explain why infected endothelial cells in hantavirus-infected patients are not destroyed by the strong cytotoxic lymphocyte response.

  8. In vitro generation of human cytotoxic lymphocytes by virus. Viral glycoproteins induce nonspecific cell-mediated cytotoxicity without release of interferon



    Purified hemagglutinin and fusion glycoproteins of measles virus either in soluble form or inserted in artifical membranes bind to human peripheral blood lymphocytes and induce cell-mediated cytotoxicity (CMC) in a dose-response fashion. Both autologous and heterologous noninfected target cells are lysed in vitro. The expression of CMC is not inhibited by anti-measles virus antibody added to lymphocytes previously exposed to viral glycoproteins. THe killer lymphocytes are Fc receptor positive...

  9. Dendritic cells transduced with Rsf-1/HBXAP gene generate specific cytotoxic T lymphocytes against ovarian cancer in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Li [Department of Gynecology Oncology, Shan Dong Tumor Hospital, Jinan, Shandong (China); Department of Obstetrics and Gynecology, Qilu Hospital, Shandong University, Jinan, Shandong (China); Kong, Beihua, E-mail: [Department of Obstetrics and Gynecology, Qilu Hospital, Shandong University, Jinan, Shandong (China); Sheng, Xiugui [Department of Gynecology Oncology, Shan Dong Tumor Hospital, Jinan, Shandong (China); Sheu, Jim Jinn-Chyuan [Human Genetic Center, China Medical University Hospital and Graduate Institute of Chinese Medical Science, China Medical University, Taichung City, Taiwan (China); Shih, Ie-Ming [Departments of Pathology, Oncology, and Gynecology and Obstetrics, Johns Hopkins Medical Institutions, Baltimore, MD 21231 (United States)


    Recently, some studies have indicated that Rsf-1/HBXAP plays a role in chromatin remodeling and transcriptional regulation that may contribute to tumorigenesis in ovarian cancer. The present study demonstrates that using dendritic cells (DCs) from human cord blood CD34{sup +} cells transduced with Rsf-1/HBXAP DNA plasmids by nucleofection generate specific cytotoxic T lymphocytes (CTL) against ovarian cancer in vitro. After transfection, DCs were analyzed for Rsf-1/HBXAP mRNA expression by RT-PCR and protein expression by Western blot. Then the DC phenotypes, T-cell stimulatory capacity, endocytic activity and migration capacity were explored by flow cytometry analysis, allogeneic mixed lymphocyte reaction, endocytosis and transwell chemotaxis assay, respectively. After transfection, Rsf-1/HBXAP expression was detected at mRNA and protein levels. Allogeneic T-cell proliferation induced by transfected DCs was obviously higher than non-transfected DCs, but the endocytosis capacity and migratory ability were not different. Rsf-1/HBXAP gene-transduced DCs could induce antigen-specific CTL and generate a very potent cytotoxicity to OVCAR3 cells. These data suggest that Rsf-1/HBXAP gene-transduced DCs may be a potential adjuvant immunotherapy for ovarian cancer in clinical applications.

  10. Assessment of cytotoxic and genotoxic potential of pyracarbolid by Allium test and micronucleus assay. (United States)

    Özkara, Arzu; Akyıl, Dilek; Eren, Yasin; Erdoğmuş, S Feyza; Konuk, Muhsin; Sağlam, Esra


    The present study evaluates the cytotoxic and genotoxic potential of pyracarbolid using both micronuleus (MN) assay, in human lymphocytes, and Allium cepa assay, in the root meristem cells. In Allium test, EC50 value was determined in order to selecting the test concentrations for the assay and the root tips were treated with 25 ppm (EC50/2), 50 ppm (EC50) and 100 ppm (EC50 × 2) concentrations of pyracarbolid. One percent of dimethyl sulphoxide (DMSO) and methyl methane sulfonate (MMS) were used as negative and positive controls, respectively. In the micronucleus assay, the cultures were treated with four concentrations (250, 500, 750 and 1000 µg/ml) of pyracarbolid for 24 and 48 h, negative and positive controls were also used in the experiment parallely. The results showed that mitotic index (MI) significantly reduced with increasing the pyracarbolid concentration at each exposure time. It was also obtained that prophase and metaphase index decreased significantly in all concentration at each exposure time. Anaphase index decreased as well and results were found to be statistically significant, except 24 h. A significant increase was observed in MN frequency in all concentrations and both treatment periods when compared with the controls. Pyracarbolid also caused a significant reduction in the cytokinesis block proliferation index (CBPI) in all concentration and both exposure time.

  11. Cytotoxic and clastogenic activity of CdCl2 in human lymphocytes from different donors. (United States)

    Gateva, Svetla; Jovtchev, Gabriele; Stergios, Mila


    The sensitivity of human lymphocytes from different donors to CdCl2 using a complex of methods for determination of cytotoxicity and genotoxicity was studied. As endpoints for cytotoxicity the mitotic index (MI) and apoptosis were evaluated. To indicate genotoxicity chromosome aberrations test (CA) was used. The results indicate an individual sensitivity of lymphocytes to CdCl2-induced damage, which is directly depending on the concentration (10(-6), 10(-5), 5×10(-5), 10(-4)mol/l) applied. The assessment of the toxic and genotoxic effect using various endpoints allows more complete risk estimation for organisms exposed to heavy metals. The results have direct practical significance for threat evaluation in humans. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Dengue virus-specific cross-reactive CD8+ human cytotoxic T lymphocytes.


    Bukowski, J F; Kurane, I; Lai, C J; Bray, M.; Falgout, B.; Ennis, F A


    Stimulation with live dengue virus of peripheral blood mononuclear cells from a dengue virus type 4-immune donor generated virus-specific, serotype-cross-reactive, CD8+, class I-restricted cytotoxic T lymphocytes (CTL) capable of lysing dengue virus-infected cells and cells pulsed with dengue virus antigens of all four serotypes. These CTL lysed autologous fibroblasts infected with vaccinia virus-dengue virus recombinant viruses containing the E gene or several nonstructural dengue virus type...

  13. Periodic loss of reactivity of a myeloma tumor with cytotoxic thymus-derived lymphocytes. (United States)

    Russell, J H; Hale, A H; Ginns, L C; Eisen, H N


    During each transplantation passage of a line of mouse myeloma tumor MOPC-315 through syngeneic (BALB/c) hosts, the tumor cells lose reactivity with cytotoxic thymus-derived lymphocytes directed against products of the BALB/c major histocompatibility complex (H-2d) and regain reactivity on transfer to fresh hosts. In contrast to this cyclical change, the tumor cells remain uniformly reactive with anti-H-2d alloantisera throughout the transplantation cycle. PMID:75547

  14. Antigenic drift in the influenza A virus (H3N2) nucleoprotein and escape from recognition by cytotoxic T lymphocytes

    NARCIS (Netherlands)

    T.M. Bestebroer (Theo); N.J. Nieuwkoop; R.A.M. Fouchier (Ron); G.F. Rimmelzwaan (Guus); J.T.M. Voeten; A.D.M.E. Osterhaus (Ab)


    textabstractViruses exploit different strategies to escape immune surveillance, including the introduction of mutations in cytotoxic T-lymphocyte (CTL) epitopes. The sequence of these epitopes is critical for their binding to major histocompatibility complex (MHC) class I molecules

  15. Cytotoxicity evaluation of the whole protein extract from Bar-transgenic rice on Mus musculus lymphocytes. (United States)

    Lu, X B


    With the expanding demand for genetically modified (GM) rice, its safety evaluation is of great significance. Therefore, this study was carried out to assess the acute cytotoxicity of the whole protein extract from GM rice Bar68-1 in Mus musculus lymphocytes in vitro. Cell viability was determined by Cell Counting Kit-8 (CCK-8) and Neutral Red Uptake (NRU) tests. CCK-8 tests was carried out according to the manufacturer's instructions. Cell dehydrogenase (catalytic redox enzymes) activity was spectrophotometrically determined at 450 nm. The tests result were recorded immediately. NRU tests were completed under yellow light in a dark room according to an improved protocol. Lysosomal uptake of neutral red was spectrophotometrically determined at 540 nm and the results were recorded immediately. The results showed that the survival rate of M. musculus lymphocytes in the positive control group was significantly less than in the blank control group (P tests. There was no significant difference in survival rate between GM rice Bar68-1group and non-GM rice D68 group (P > 0.05). The GM rice Bar68-1 group also did not show a higher survival rate than non-GM rice D68 group (P > 0.05). These results suggested that the whole protein extract from Bar68-1 and D68 were equivalent in their cytotoxicity, and GM rice Bar68-1 had no acute cytotoxic effect on M. musculus lymphocytes in vitro.

  16. Genotoxicity and cytotoxicity of copper oxychloride in cultured human lymphocytes using cytogenetic and molecular tests. (United States)

    Bayram, Suleyman; Genc, Ahmet; Buyukleyla, Mehmet; Rencuzogullari, Eyyup


    The genotoxicity of copper oxychloride was investigated in human lymphocytes using chromosome aberration (CA) and micronucleus (MN) tests and the randomly amplified polymorphic DNA-polymerase chain reaction technique. The lymphocytes were treated with 3, 6, and 12 µg/mL of copper oxychloride for 24 and 48 h. Copper oxychloride increased CA and abnormal cells in a dose-dependent manner. The frequency of MN and micronucleated binuclear cells also increased at all concentrations and treatment periods. However, copper oxychloride cytotoxicity, observed through lower mitotic and nuclear division index, was significantly lower only at the higher concentrations (6 and 12 µg/mL). Copper oxychloride increased the polymorphic bands and decreased genomic template stability. In conclusion, in this study it was confirmed that copper oxychloride has genotoxic potential for human lymphocytes in vitro. Additionally, caution is advised for its use as a fungicide, because it may increase the risk of exposure through the food chain.

  17. The Pavonia xanthogloea (Ekman, Malvaceae: Phenolic compounds quantification, anti-oxidant and cytotoxic effect on human lymphocytes cells

    Directory of Open Access Journals (Sweden)

    Clarice Pinheiro Mostardeiro


    Full Text Available Introduction: Pavonia xanthogloea is traditionally used as an antimicrobial and anti-tumour medicine in Southern Brazilian region. However, investigations about this species are still incipient. Hypothesis Tested: The study postulated that P. xanthologea specie present some phenolic compound and present some biological properties as anti-oxidant and cytoprotective effect against oxidative stress. Materials and Methods: The content of eight phenolic molecules in the crude ethanolic extract of the aerial part of P. xanthogloea and its five fractions (hexane, dichloromethane, ethyl-acetate, n-butanol, and water was determined by heterotrophic plate count method. The anti-oxidant capacity of the extract and the fractions was determined by 1,1-diphenyl-2-picryl-hydrazyl assay. The potential anti-oxidant and cytoprotective effect was also analyzed in human lymphocyte culture treated with extract/fractions at different concentrations with and without oxidative stress generated by hydrogen peroxide (H 2 O 2 and sodium nitroprusside (SNP exposition. Results: Tiliroside was the molecule detected in all extract. Water and ethyl-acetate fractions showed the highest radical-scavenging activity. The crude extract, hexane, water, and n-butanol reversed the higher reactive oxygen specie levels generated by H 2 O 2 and SNP to levels similar to those observed in the control group. In addition, crude extract, hexane, ethyl-acetate and n-butanol did not caused cytotoxicity, whereas water fraction was cytotoxic at higher concentration tested here (300 μg/mL. The cytotoxicity reversion caused by SNP exposition was concentration-dependent of the extract and fractions. However, dichloromethane fraction increased cell mortality in all concentrations investigated and was not able to decrease cell death in the lymphocytes exposed to SNP. Conclusion: The results suggest potential medicine use of this species.

  18. Identification of the epitopes on HCV core protein recognized by HLA-A2 restricted cytotoxic T lymphocytes

    Institute of Scientific and Technical Information of China (English)

    Hong-Chao Zhou; De-Zhong Xu; Xue-Ping Wang; Jing-Xia Zhang; Ying-Huang; Yong-Ping Yan; Yong Zhu; Bo-Quan Jin


    AIM To identify hepatitis C virus (HCV) core protein epitopes recognized by HLA-A2 restricted cytotoxic T lymphocyte (CTL). METHODS Utilizing the method of computer prediction followed by a 4 h 51 Cr-release assay confirmation. RESULTS The results showed that peripheral blood mononuclear cells (PBMC) obtained from two HLA-A2 positive donors who were infected with HCV could lyse autologous target cells labeled with peptide "ALAHGVFAL (core TS0-158)".The rates of specific lysis of the cells from the two donors were 37.5% and 15.8%,respectively. Blocking of the CTL response with anti-CD4 mAb caused no significant decrease of the specific lysis.But blocking of CTL response with anti-CD8 mAb could abolish the Iysis. CONCLUSION The peptide (core 150 - 158 ) is the candidate epitope recognized by HLA-A2 restricted CTL.

  19. Identification of cytotoxic T lymphocyte epitopes in dengue virus serotype 1. (United States)

    Duan, Zhiliang; Guo, Jianglong; Huang, Xi; Liu, Huifang; Chen, Xinyu; Jiang, Minghua; Wen, Jinsheng


    Dengue virus (DENV) has a serious and growing impact on global health and the exact role of DENV-specific CD8(+) T-cells in DENV infection is still uncertain. In the present study, SYFPEITHI algorithm was used to screen the amino acid sequence of Dengue virus serotype 1 (DENV-1) for potential epitopes, and seven putative HLA-A*1101-restricted and five putative HLA-A*2402-restricted epitopes conserved in hundreds of DENV-1 strains were synthesized. The binding affinity of these epitope candidates to corresponding HLA molecules was evaluated using competitive peptide-binding assay. The immunogenicity and specificity of peptides were further tested in HLA-A*1101 transgenic mice, HLA-A*2402 transgenic mice and peripheral blood mononuclear cells (PBMCs) of patients infected with DENV-1. Percentage inhibition (PI) values calculated in competitive peptide-binding assay showed that six peptides (E39-47 PTLDIELLK, NS5(505-513) GVEGEGLHK, NS2b(15-23) SILLSSLLK, NS5(561-569) ALLATSIFK, NS3(99-107) AVEPGKNPK, and NS4b(159-167) VVYDAKFEK) could bind to HLA-A*1101 molecule with high affinity and five peptides (NS3472-480 QYIYMGQPL, NS4a40-48 AYRHAMEEL, NS5(880-888) DYMTSMKRF, NS3(548-556) SYKVASEGF, and NS3(22-30) IYRILQRGL) have a high affinity for HLA-A*2402 molecule. Enzyme-linked immunospot (ELISPOT) results indicated that these high-affinity peptides were recognized by splenocytes of DENV-1-infected transgenic mice and high-affinity peptide-immunized transgenic mice displayed high levels of peptide-specific IFN-γ-secreting cells. In addition, both peptide-pulsed splenocytes and DENV-1-infected splenic monocytes were efficiently killed by these peptide-specific cytotoxic T lymphocytes. Finally, except NS2b(15-23), 10 high-affinity peptides were recognized by PBMCs of patients infected with DENV-1. These identified epitopes would contribute to the understanding of the function of DENV-specific CD8(+) T-cells.


    Directory of Open Access Journals (Sweden)

    S. V. Khaidukov


    Full Text Available Abstract. Determination of lymphocyte subpopulations and their phenotypes is an important diagnostic feature, in order to elucidate some disturbances connected with immune system functioning. However, insufficient data are obtained when analyzing only major populations of peripheral lymphocytes. In order to perform clinical diagnostics, the data about minor lymphocytic populations and activated cellular pools seem to be more pertinent.Studies of peripheral blood cell subpopulations of healthy donors performed in different Russian regions allowed to assess quantitative distribution intervals for both major and minor immune cell subpopulations in humans. The results obtained, as compared with data from literature, provide an evidence for similar reference intervals for main immune cell subpopulations in healthy donors, independent on their habitation area.Present work has resulted into development of algorithms for cytometric studies and generation of certain panels of monoclonal antibodies enabling evaluation of all main lymphocyte subpopulations, as well as their minor subsets participating in emerging immune response. The distribution intervals have been estimated for such minor subpopulations, as B1- and B2-lymphocytes, memory B-cells, γδ- and αβT-cells, regulatory and naїve T-cells, cytotoxic and secretory NK-cell polupations.The results of present study, while been performed with peripheral blood of healthy donors, may provide a basis of reference values when studying subpopulation profile of immune cells.

  1. Evaluation of Genotoxic and Cytotoxic Effects in Human Peripheral Blood Lymphocytes Exposed In Vitro to Neonicotinoid Insecticides News

    Directory of Open Access Journals (Sweden)

    María Elena Calderón-Segura


    Full Text Available Calypso (thiacloprid, Poncho (clothianidin, Gaucho (imidacloprid, and Jade (imidacloprid are commercial neonicotinoid insecticides, a new class of agrochemicals in México. However, genotoxic and cytotoxic studies have not been performed. In the present study, human peripheral blood lymphocytes (PBL were exposed in vitro to different concentrations of the four insecticides. The genotoxic and cytotoxic effects were evaluated using the alkaline comet and trypan blue dye exclusion assays. DNA damage was evaluated using two genotoxicity parameters: tail length and comet frequency. Exposure to 9.5×10-6 to 5.7×10-5 M Jade; 2.8×10-4 to 1.7×10-3 M Gaucho; 0.6×10-1 to 1.4×10-1 M Calypso; 1.2×10-1 to 9.5×10-1 M Poncho for 2 h induced a significant increase DNA damage with a concentration-dependent relationship. Jade was the most genotoxic of the four insecticides studied. Cytotoxicity was observed in cells exposed to 18×10-3 M Jade, 2.0×10-3 M Gaucho, 2.0×10-1 M Calypso, 1.07 M Poncho, and cell death occurred at 30×10-3 M Jade, 3.3×10-3 M Gaucho, 2.8×10-1 M Calypso, and 1.42 M Poncho. This study provides the first report of genotoxic and cytotoxic effects in PBL following in vitro exposure to commercial neonicotinoid insecticides.

  2. Evaluation of Genotoxic and Cytotoxic Effects in Human Peripheral Blood Lymphocytes Exposed In Vitro to Neonicotinoid Insecticides News (United States)

    Calderón-Segura, María Elena; Gómez-Arroyo, Sandra; Villalobos-Pietrini, Rafael; Martínez-Valenzuela, Carmen; Carbajal-López, Yolanda; Calderón-Ezquerro, María del Carmen; Cortés-Eslava, Josefina; García-Martínez, Rocío; Flores-Ramírez, Diana; Rodríguez-Romero, María Isabel; Méndez-Pérez, Patricia; Bañuelos-Ruíz, Enrique


    Calypso (thiacloprid), Poncho (clothianidin), Gaucho (imidacloprid), and Jade (imidacloprid) are commercial neonicotinoid insecticides, a new class of agrochemicals in México. However, genotoxic and cytotoxic studies have not been performed. In the present study, human peripheral blood lymphocytes (PBL) were exposed in vitro to different concentrations of the four insecticides. The genotoxic and cytotoxic effects were evaluated using the alkaline comet and trypan blue dye exclusion assays. DNA damage was evaluated using two genotoxicity parameters: tail length and comet frequency. Exposure to 9.5 × 10−6 to 5.7 × 10−5 M Jade; 2.8 × 10−4 to 1.7 × 10−3 M Gaucho; 0.6 × 10−1 to 1.4 × 10−1 M Calypso; 1.2 × 10−1 to 9.5 × 10−1 M Poncho for 2 h induced a significant increase DNA damage with a concentration-dependent relationship. Jade was the most genotoxic of the four insecticides studied. Cytotoxicity was observed in cells exposed to 18 × 10−3 M Jade, 2.0 × 10−3 M Gaucho, 2.0 × 10−1 M Calypso, 1.07 M Poncho, and cell death occurred at 30 × 10−3 M Jade, 3.3 × 10−3 M Gaucho, 2.8 × 10−1 M Calypso, and 1.42 M Poncho. This study provides the first report of genotoxic and cytotoxic effects in PBL following in vitro exposure to commercial neonicotinoid insecticides. PMID:22545045

  3. In-vitro activation of cytotoxic T lymphocytes by fusion of mouse hepatocellular carcinoma cells and lymphotactin gene-modified dendritic cells

    Institute of Scientific and Technical Information of China (English)


    AIM: To investigate the in-vitro activation of cytotoxic T lymphocytes (CTLs) by fusion of mouse hepatocellular carcinoma (HCC) cells and lymphotactin gene-modified dendritic cells (DCs).METHODS: Lymphotactin gene modified DCs (DCLptn) were prepared by lymphotactin recombinant adenovirus transduction of mature DCs which differentiated from mouse bone marrow cells by stimulation with granulocyte/macrophage colony-stimulating factor (GM-CSF), interleukin-4 (IL-4) and tumor necrosis factor alpha (TNF-α). DCLptn and H22 fusion was prepared using 50% PEG. Lymphotactin gene and protein expression levels were measured by RT-PCR and ELISA, respectively. Lymphotactin chemotactic responses were examined by in-vitro chemotaxis assay. In-vitro activation of CTLs by DCLptn/H22 fusion was measured by detecting CD25 expression and cytokine production after autologous T cell stimulation. Cytotoxic function of activated T lymphocytes stimulated with DCLptn/H22 cells was determined by LDH cytotoxicity assay.RESULTS: Lymphotactin gene could be efficiently transduced to DCs by adenovirus vector and showed an effective biological activity. After fusion, the hybrid DCLptn/H22 cells acquired the phenotypes of both DCLptn and H22 cells. In T cell proliferation assay, flow cytometry showed a very high CD25 expression, and cytokine release assay showed a significantly higher concentration of IFN-γ and IL-2 in DCLptn/H22 group than in DCLptn, DCLptn+H22, DC/H22 or H22 groups. Cytotoxicity assay revealed that T cells derived from DCLptn/H22 group had much higher anti-tumor activity than those derived from DCLptn, H22, DCLptn + H22, DC/H22 groups.CONCLUSION: Lymphotactin gene-modified dendritoma induces T-cell proliferation and strong CTL reaction against allogenic HCC cells. Immunization-engineered fusion hybrid vaccine is an attractive strategy in prevention and treatment of HCC metastases.

  4. Cytotoxic T lymphocyte antigen-4 (CTLA-4 A49G polymorphism and autoimmune blood diseases

    Directory of Open Access Journals (Sweden)

    Faruk Aktürk


    Full Text Available Objective: The cytotoxic T lymphocyte associated antigen-4 (CTLA-4 is expressed on T lymphocytes, and inhibits the T-cell responses. In animal models, it has been shown that complete CTLA-4 deficiency was lethal due to massive infiltration of tissues by polyclonally proliferating lymphocytes. CTLA-4 A49G polymorphism, which has been suggested to reduce the inhibitory function of the CTLA-4 molecule, was found to be associated with various autoimmune diseases in recent studies. Material and Methods: In this study, we evaluated the frequency of CTLA-4 A49G polymorphism in 46 patients with autoimmune hemolytic anemia (AIHA, 62 patients with immune thrombocytopenic purpura (ITP, and 150 healthy individuals. Results: Allele frequencies and genotype distributions were similar in both ITP and AIHA patients compared to healthy individuals. In subgroup analysis, however, we found that in chronic lymphocytic leukemia (CLL patients with AIHA (n=4, all patients had CTLA-4 A49G polymorphism (3 had AG, 1 had GG. There was no significant statistical association between G allele and systemic lupus erythematosus (SLE or AIHA.Conclusion: These data suggest that CTLA-4 A49G polymorphism does not contribute to the pathogenesis of lymphoproliferative diseases itself, nor does it increase the risk of autoimmune complications in patients with lymphoproliferative disease.

  5. Human CD56+ cytotoxic lung lymphocytes kill autologous lung cells in chronic obstructive pulmonary disease.

    Directory of Open Access Journals (Sweden)

    Christine M Freeman

    Full Text Available CD56+ natural killer (NK and CD56+ T cells, from sputum or bronchoalveolar lavage of subjects with chronic obstructive pulmonary disease (COPD are more cytotoxic to highly susceptible NK targets than those from control subjects. Whether the same is true in lung parenchyma, and if NK activity actually contributes to emphysema progression are unknown. To address these questions, we performed two types of experiments on lung tissue from clinically-indicated resections (n = 60. First, we used flow cytometry on fresh single-cell suspension to measure expression of cell-surface molecules (CD56, CD16, CD8, NKG2D and NKp44 on lung lymphocytes and of the 6D4 epitope common to MICA and MICB on lung epithelial (CD326+ cells. Second, we sequentially isolated CD56+, CD8+ and CD4+ lung lymphocytes, co-cultured each with autologous lung target cells, then determined apoptosis of individual target cells using Annexin-V and 7-AAD staining. Lung NK cells (CD56+ CD3- and CD56+ T cells (CD56+ CD3+ were present in a range of frequencies that did not differ significantly between smokers without COPD and subjects with COPD. Lung NK cells had a predominantly "cytotoxic" CD56+ CD16+ phenotype; their co-expression of CD8 was common, but the percentage expressing CD8 fell as FEV1 % predicted decreased. Greater expression by autologous lung epithelial cells of the NKG2D ligands, MICA/MICB, but not expression by lung CD56+ cells of the activating receptor NKG2D, correlated inversely with FEV1 % predicted. Lung CD56+ lymphocytes, but not CD4+ or CD8+ conventional lung T cells, rapidly killed autologous lung cells without additional stimulation. Such natural cytotoxicity was increased in subjects with severe COPD and was unexplained in multiple regression analysis by age or cancer as indication for surgery. These data show that as spirometry worsens in COPD, CD56+ lung lymphocytes exhibit spontaneous cytotoxicity of autologous structural lung cells, supporting their

  6. Large-scale validation of methods for cytotoxic T-lymphocyte epitope prediction

    DEFF Research Database (Denmark)

    Larsen, Mette Voldby; Lundegaard, Claus; Lamberth, K.


    BACKGROUND: Reliable predictions of Cytotoxic T lymphocyte (CTL) epitopes are essential for rational vaccine design. Most importantly, they can minimize the experimental effort needed to identify epitopes. NetCTL is a web-based tool designed for predicting human CTL epitopes in any given protein....... of the other methods achieved a sensitivity of 0.64. The NetCTL-1.2 method is available at used datasets are available at

  7. Large-scale validation of methods for cytotoxic T-lymphocyte epitope prediction

    DEFF Research Database (Denmark)

    Larsen, Mette Voldby; Lundegaard, Claus; Lamberth, K.;


    BACKGROUND: Reliable predictions of Cytotoxic T lymphocyte (CTL) epitopes are essential for rational vaccine design. Most importantly, they can minimize the experimental effort needed to identify epitopes. NetCTL is a web-based tool designed for predicting human CTL epitopes in any given protein....... of the other methods achieved a sensitivity of 0.64. The NetCTL-1.2 method is available at used datasets are available at

  8. Treatment of solid organ transplant recipients with autologous Epstein Barr virus–specific cytotoxic T lymphocytes (CTLs) (United States)

    Savoldo, Barbara; Goss, John A.; Hammer, Markus M.; Zhang, Lan; Lopez, Teresita; Gee, Adrian P.; Lin, Yu-Feng; Quiros-Tejeira, Ruben E.; Reinke, Petra; Schubert, Stephan; Gottschalk, Stephen; Finegold, Milton J.; Brenner, Malcolm K.; Rooney, Cliona M.; Heslop, Helen E.


    We have investigated the in vivo safety, efficacy, and persistence of autologous Epstein Barr virus (EBV)–specific cytotoxic T lymphocytes (CTLs) for the treatment of solid organ transplant (SOT) recipients at high risk for EBV-associated posttransplantation lymphoproliferative disease (PTLD). EBV-CTLs generated from 35 patients expanded with normal kinetics contained both CD8 and CD4 lymphocytes and produced significant specific killing of autologous EBV-transformed B lymphoblastoid cell lines (LCLs). Twelve SOT recipients at high risk for PTLD, or with active disease, received autologous CTL infusions without toxicity. Real-time polymerase chain reaction (PCR) monitoring of EBV-DNA showed a transient increase in plasma EBV-DNA suggestive of lysis of EBV-infected cells, although there was no consistent decrease in virus load in peripheral-blood mononuclear cells. Interferon-γ enzyme-linked immunospot (ELISPOT) assay and tetramer analysis showed an increase in the frequency of EBV-responsive T cells, which returned to preinfusion levels after 2 to 6 months. None of the treated patients developed PTLD. One patient with liver PTLD showed a complete response, and one with ocular disease has had a partial response stable for over one year. These data are consistent with an expansion and persistence of adoptively transferred EBV-CTLs that is limited in the presence of continued immunosuppression but that nonetheless produces clinically useful antiviral activity. PMID:16835376

  9. Comparative cytotoxic and genotoxic potential of 13 drinking water disinfection by-products using a microplate-based cytotoxicity assay and a developed SOS/umu assay. (United States)

    Zhang, Shao-Hui; Miao, Dong-Yue; Tan, Li; Liu, Ai-Lin; Lu, Wen-Qing


    The implications of disinfection by-products (DBPs) present in drinking water are of public health concern because of their potential mutagenic, carcinogenic and other toxic effects on humans. In this study, we selected 13 main DBPs found in drinking water to quantitatively analyse their cytotoxicity and genotoxicity using a microplate-based cytotoxicity assay and a developed SOS/umu assay in Salmonella typhimurium TA1535/pSK1002. With the developed SOS/umu test, eight DBPs: 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-fura3-chloro-4-(dichloromethyl)-5-hydroxy-2-[5H]-furanone (MX), dibromoacetonitrile (DBN), iodoacetic acid (IA), bromochloroacetonitrile (BCN), bromoacetic acid (BA), trichloroacetonitrile (TCN), dibromoacetic acid (DBA) and dichloroacetic acid (DCA) were significantly genotoxic to S. typhimurium. Three DBPs: chloroacetic acid (CA), trichloroacetic acid (TCA) and dichloroacetonitrile (DCN) were weakly genotoxic, whereas the remaining DBPs: chloroacetonitrile (CN) and chloral hydrate (CH) were negative. The rank order in decreasing genotoxicity was as follows: MX > DBN > IA > BCN > BA > TCN > DBA > DCA > CA, TCA, DCN > CN, CH. MX was approximately 370 000 times more genotoxic than DCA. In the microplate-based cytotoxicity assay, cytotoxic potencies of the 13 DBPs were compared and ranked in decreasing order as follows: MX > IA > DBN > BCN > BA > TCN > DCN > CA > DCA > DBA > CN > TCA > CH. MX was approximately 19 200 times more cytotoxic than CH. A statistically significant correlation was found between cytotoxicity and genotoxicity of the 13 DBPs in S. typhimurium. Results suggest that microplate-based cytotoxicity assay and the developed SOS/umu assay are feasible tools for analysing the cytotoxicity and genotoxicity of DBPs, particularly for comparing their toxic intensities quantitatively.

  10. Protective Effect of Onion Extract on Bleomycin-Induced Cytotoxicity and Genotoxicity in Human Lymphocytes

    Directory of Open Access Journals (Sweden)

    Yoon Hee Cho


    Full Text Available Following one of the world’s largest nuclear accidents, occured at Fukushima, Japan in 2011, a significant scientific effort has focused on minimizing the potential adverse health effects due to radiation exposure. The use of natural dietary antioxidants to reduce the risk of radiation-induced oxidative DNA damage is a simple strategy for minimizing radiation-related cancer rates and improving overall health. The onion is among the richest sources of dietary flavonoids and is an important food for increasing their overall intake. Therefore, we examined the effect of an onion extract on cyto- and geno-toxicity in human lymphocytes treated with bleomycin (BLM, a radiomimetic agent. In addition, we measured the frequency of micronuclei (MN and DNA damage following treatment with BLM using a cytokinesis-blocked micronucleus assay and a single cell gel electrophoresis assay. We observed a significant increase in cell viability in lymphocytes treated with onion extract then exposed to BLM compared to cells treated with BLM alone. The frequency of BLM induced MN and DNA damage increased in a dose-dependent manner; however, when lymphocytes were pretreated with onion extract (10 and 20 μL/mL, the frequency of BLM-induced MN was decreased at all doses of BLM and DNA damage was decreased at 3 μg/mL of BLM. These results suggest that onion extract may have protective effects against BLM-induced cyto- and genotoxicity in human lymphocytes.

  11. Persistent virus infection despite chronic cytotoxic T-lymphocyte activation in gamma interferon-deficient mice infected with lymphocytic choriomeningitis virus

    DEFF Research Database (Denmark)

    Bartholdy, C; Christensen, Jan Pravsgaard; Wodarz, D;


    ). While wild-type mice rapidly cleared the infection, IFN-gamma -/- mice became chronically infected. Virus persistence in the latter mice did not reflect failure to generate cytotoxic T-lymphocyte (CTL) effectors, as an unimpaired primary CTL response was observed. Furthermore, while ex vivo CTL activity...

  12. The low molecular weight DNA diffusion assay as an indicator of cytotoxicity for the in vitro comet assay. (United States)

    Speit, Günter; Vesely, Alexandra; Schütz, Petra; Linsenmeyer, Regina; Bausinger, Julia


    The low molecular weight DNA diffusion assay (LMW assay) has been recommended as a measure for cytotoxicity for the in vivo comet assay. To better understand the relationship between effects in the LMW assay, DNA migration in the comet assay and effects in established cytotoxicity tests, we performed in vitro experiments with cultured human cell lines (TK6, A549) and comparatively investigated five test substances (methyl methanesulfonate, (±)-benzo[a]pyrene diol epoxide, sodium dodecyl sulphate, menthol and sodium arsenite). We measured DNA migration (tail intensity) in the comet assay and the frequency of 'hedgehogs' (cells with almost all DNA in the tail), DNA diffusion in the LMW assay, cell viability (trypan blue and fluorescein diacetate/ethidium bromide staining) and inhibition of proliferation (relative cell counts). Our in vitro experiments indicate that effects in the LMW assay occur independently from DNA effects in the comet assay and are not related to the occurrence of hedgehogs. Results from the LMW assay are in good agreement with results from viability assays and seem to allow discriminating genotoxic from non-genotoxic substances when appropriate preparation times are considered. Measurements of cytotoxicity by these methods only at an early preparation time after exposure to genotoxic substances may lead to erroneous results.

  13. CRISPR knock out CTLA-4 enhances the anti-tumor activity of cytotoxic T lymphocytes. (United States)

    Shi, Long; Meng, Tongyu; Zhao, Zhilong; Han, Jinsheng; Zhang, Wei; Gao, Fei; Cai, Jianhui


    T cell-mediated anti-tumor immunity plays a pivotal role in cancer immune surveillance. Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is a protein receptor mainly expressed in activated T cells and regulatory T cells. CTLA-4 competes with CD28 for ligand binding and generates inhibitory signals to attenuate T cell activation. The blockade of CTLA-4 mediated immune inhibitory checkpoint has been associated with enhanced anti-tumor immunity. In this study, we use CRISPR-Cas9 system to knock out (KO) CTLA-4 from cytotoxic T lymphocytes (CTLs) and evaluate its effect on the anti-tumor activity of the CTLs. CTLA-4 KO CTLs robustly enhanced tumor cell death by 40% compared to the control and facilitated apoptosis and caspase activities in tumor cells. The knockout of CTLA-4 also increased TNF-α and IFN-γ secretion of the CTLs by approximately 2-fold. The effectiveness of CTLA-4 KO in enhancing anti-tumor activity of the CTLs was verified in vivo using mouse xenograft model. The xenografted mice treated with CTLA-4 KO CTLs demonstrated repressed tumor growth and prolonged survival compared to the control group. Our data suggest that CRISPR targeting CTLA-4 immune checkpoint could significantly improve the anti-tumor activity of CTLs. Copyright © 2017. Published by Elsevier B.V.

  14. Role of vitamin D in cytotoxic T lymphocyte immunity to pathogens and cancer. (United States)

    Sarkar, Surojit; Hewison, Martin; Studzinski, George P; Li, Yan Chun; Kalia, Vandana


    The discovery of vitamin D receptor (VDR) expression in immune cells has opened up a new area of research into immunoregulation by vitamin D, a niche that is distinct from its classical role in skeletal health. Today, about three decades since this discovery, numerous cellular and molecular targets of vitamin D in the immune system have been delineated. Moreover, strong clinical associations between vitamin D status and the incidence/severity of many immune-regulated disorders (e.g. infectious diseases, cancers and autoimmunity) have prompted the idea of using vitamin D supplementation to manipulate disease outcome. While much is known about the effects of vitamin D on innate immune responses and helper T (T(H)) cell immunity, there has been relatively limited progress on the frontier of cytotoxic T lymphocyte (CTL) immunity--an arm of host cellular adaptive immunity that is crucial for the control of such intracellular pathogens as human immunodeficiency virus (HIV), tuberculosis (TB), malaria, and hepatitis C virus (HCV). In this review, we discuss the strong historical and clinical link between vitamin D and infectious diseases that involves cytotoxic T lymphocyte (CTL) immunity, present our current understanding as well as critical knowledge gaps in the realm of vitamin D regulation of host CTL responses, and highlight potential regulatory connections between vitamin D and effector and memory CD8 T cell differentiation events during infections.

  15. Accurate non-invasive image-based cytotoxicity assays for cultured cells

    Directory of Open Access Journals (Sweden)

    Brouwer Jaap


    Full Text Available Abstract Background The CloneSelect™ Imager system is an image-based visualisation system for cell growth assessment. Traditionally cell proliferation is measured with the colorimetric MTT assay. Results Here we show that both the CloneSelect Imager and the MTT approach result in comparable EC50 values when assaying the cytotoxicity of cisplatin and oxaliplatin on various cell lines. However, the image-based technique was found non-invasive, considerably quicker and more accurate than the MTT assay. Conclusions This new image-based technique has the potential to replace the cumbersome MTT assay when fast, unbiased and high-throughput cytotoxicity assays are requested.

  16. FluxCTTX: A LIMS-based tool for management and analysis of cytotoxicity assays data. (United States)

    Faria-Campos, Alessandra C; Balottin, Luciene B; Zuin, Gianlucca; Garcia, Vinicius; Batista, Paulo H S; Granjeiro, José M; Campos, Sérgio V A


    Cytotoxicity assays have been used by researchers to screen for cytotoxicity in compound libraries. Researchers can either look for cytotoxic compounds or screen "hits" from initial high-throughput drug screens for unwanted cytotoxic effects before investing in their development as a pharmaceutical. These assays may be used as an alternative to animal experimentation and are becoming increasingly important in modern laboratories. However, the execution of these assays in large scale and different laboratories requires, among other things, the management of protocols, reagents, cell lines used as well as the data produced, which can be a challenge. The management of all this information is greatly improved by the utilization of computational tools to save time and guarantee quality. However, a tool that performs this task designed specifically for cytotoxicity assays is not yet available. In this work, we have used a workflow based LIMS -- the Flux system -- and the Together Workflow Editor as a framework to develop FluxCTTX, a tool for management of data from cytotoxicity assays performed at different laboratories. The main work is the development of a workflow, which represents all stages of the assay and has been developed and uploaded in Flux. This workflow models the activities of cytotoxicity assays performed as described in the OECD 129 Guidance Document. FluxCTTX presents a solution for the management of the data produced by cytotoxicity assays performed at Interlaboratory comparisons. Its adoption will contribute to guarantee the quality of activities in the process of cytotoxicity tests and enforce the use of Good Laboratory Practices (GLP). Furthermore, the workflow developed is complete and can be adapted to other contexts and different tests for management of other types of data.

  17. Cytotoxic T lymphocytes and natural killer cells display impaired cytotoxic functions and reduced activation in patients with alcoholic hepatitis. (United States)

    Støy, Sidsel; Dige, Anders; Sandahl, Thomas Damgaard; Laursen, Tea Lund; Buus, Christian; Hokland, Marianne; Vilstrup, Hendrik


    The dynamics and role of cytotoxic T lymphocytes (CTLs), natural killer (NK) cells, and NKT cells in the life-threatening inflammatory disease alcoholic hepatitis is largely unknown. These cells directly kill infected and damaged cells through, e.g., degranulation and interferon-γ (IFNγ) production, but cause tissue damage if overactivated. They also assist tissue repair via IL-22 production. We, therefore, aimed to investigate the frequency, functionality, and activation state of such cells in alcoholic hepatitis. We analyzed blood samples from 24 severe alcoholic hepatitis patients followed for 30 days after diagnosis. Ten healthy abstinent volunteers and 10 stable abstinent alcoholic cirrhosis patients were controls. Using flow cytometry we assessed cell frequencies, NK cell degranulation capacity following K562 cell stimulation, activation by natural killer group 2 D (NKG2D) expression, and IL-22 and IFNγ production. In alcoholic hepatitis we found a decreased frequency of CTLs compared with healthy controls (P cells (P = 0.089). The NK cell degranulation capacity was reduced by 25% compared with healthy controls (P = 0.02) and by 50% compared with cirrhosis patients (P = 0.04). Accordingly, the NKG2D receptor expression was markedly decreased on NK cells, CTLs, and NKT cells (P cells were doubled compared with healthy controls (P < 0.05, all) but not different from cirrhosis patients. This exploratory study for the first time showed impaired cellular cytotoxicity and activation in alcoholic hepatitis. This is unlikely to cause hepatocyte death but may contribute toward the severe immune incompetence. The results warrant detailed and mechanistic studies. Copyright © 2015 the American Physiological Society.

  18. Engineered cytotoxic T lymphocytes with AFP-specific TCR gene for adoptive immunotherapy in hepatocellular carcinoma. (United States)

    Sun, Longhao; Guo, Hao; Jiang, Ruoyu; Lu, Li; Liu, Tong; He, Xianghui


    Alpha-fetoprotein (AFP) is overexpressed in hepatocellular carcinoma (HCC) and could serve as a tumor-associated antigen (TAA) and potential target for adoptive immunotherapy. However, low frequency and severe functional impairment of AFP-specific T cells in vivo hamper adoptive infusion. TAA-specific T cell receptor (TCR) gene transfer could be an efficient and reliable alternation to generate AFP-specific cytotoxic T lymphocytes (CTLs). Autologous dendritic cells (DC) pulsed with AFP158-166 peptides were used to stimulate AFP-specific CTLs. TCR α/β chain genes of AFP-specific CTLs were cloned and linked by 2A peptide to form full-length TCR coding sequence synthesized into a lentiviral vector. Nonspecific activated T cells were engineered by lentivirus infection. Transgenetic CTLs were evaluated for transfection efficiency, expression of AFP158-166-specific TCR, interferon (IFN)-γ secretion, and specific cytotoxicity toward AFP+ HCC cells in vitro and in vivo. Flow cytometry revealed the AFP158-166-MHC-Pentamer positive transgenetic CTLs was 9.86 %. The number of IFN-γ secretion T cells and the specific cytotoxicity toward HpeG2 in vitro and in tumor-bearing NOD/SCID mice were significantly raised in transgenetic CTLs than that of AFP158-166-specific CTLs obtained by peptide-pulsed DCs or control group. TCR gene transfer is a promising strategy to generate AFP158-166-specific CTLs for the treatment of HCC.

  19. Blister fluid T lymphocytes during toxic epidermal necrolysis are functional cytotoxic cells which express human natural killer (NK) inhibitory receptors (United States)

    Le Cleach, L; Delaire, S; Boumsell, L; Bagot, M; Bourgault-Villada, I; Bensussan, A; Roujeau, J C


    Toxic epidermal necrolysis (TEN) is a rare life-threatening adverse drug reaction characterized by a massive destruction of the epidermis. Immunohistological studies of skin biopsies of TEN showed infiltrates of predominantly CD8+ T lymphocytes even though other authors reported a prominent involvement of cells of the monocyte-macrophage lineage. The aim of this study was to characterize phenotypically and functionally the cells present in the cutaneous blister fluid of four patients with TEN. We first determined that lymphocytes were predominant in blister fluid obtained early, while monocytes/macrophages later became the most important population. We then showed that this lymphocyte population, mainly CD3+CD8+, corresponded to a peculiar cell subset as they expressed cutaneous leucocyte antigen, killer inhibitory receptors KIR/KAR and failed to express CD28 molecule. Functionally, we determined that blister T lymphocytes had a cytotoxic T lymphocyte (CTL)- and NK-like cytotoxicity. The role of this cytotoxic lymphocyte population present at the site of lesions during TEN remains to be understood. PMID:10606987

  20. [Rapid dicentric assay of human blood lymphocytes after exposure to low doses of ionizing radiation]. (United States)

    Repin, M V; Repina, L A


    The probability of losses of different chromosome aberrations during the dicentric chromosome assay of metaphase cells with incomplete sets of chromosome centromeres was estimated using a mathematical model for low doses of ionizing radiation. A dicentric assay of human blood lymphocytes without determination of the total amount of chromosome centromeres in cells without chromosome aberrations (rapid dicentric assay) has been proposed. The rapid dicentric analysis allows to register chromosome aberrations in full compliance with the conventional classification. The experimental data have shown no statistically significant difference between the frequencies of dicentric chromosomes detected by rapid and classical dicentric chromosome assays of human lymphocytes exposed to 0.5 Gy of 60Co gamma-rays. The rate of the rapid dicentric assay was almost twice as high as that of the classical dicentric assay.

  1. Cytotoxicity and genotoxicity assessment of Euphorbia hirta in MCF-7 cell line model using comet assay

    Institute of Scientific and Technical Information of China (English)

    Kwan Yuet Ping; Ibrahim Darah; Yeng Chen; Sreenivasan Sasidharan


    Objective:To evaluate the cytotoxicity and genotoxicity activity of Euphorbia hirta (E. hirta) in MCF-7 cell line model using comet assay. Methods: The cytotoxicity of E. hirta extract was investigated by employing brine shrimp lethality assay and the genotoxicity of E. hirta was assessed by using Comet assay. Results: Both toxicity tests exhibited significant toxicity result. In the comet assay, the E. hirta extract exhibited genotoxicity effects against MCF-7 DNA in a time-dependent manner by increasing mean percentage of DNA damage. The extract of E. hirta showed significant toxicity against brine shrimp with an LC50 value of 620.382 μg/mL (24 h). Comparison with positive control potassium dichromate signifies that cytotoxicity exhibited by the methanol extract might have moderate activity. Conclusion:The present work confirmed the cytotoxicity and genotoxicity of E. hirta. However, the observed toxicity of E. hirta extracts needs to be confirmed in additional studies.

  2. Natural killer cell cytotoxicity assay with time-resolved fluorimetry

    Institute of Scientific and Technical Information of China (English)

    李建中; 章竹君; 金伯泉; 田方


    A new time-resolved fluorimetric method for the measurement of natural killer (NK) cell cytotoxicity has been developed by labelling the target cell K562 with a new synthesized fluorescence marker KLUK. The method has advantages of higher sensitivity, time-saving, good reproducibility and has no radioactivity problems. A satisfactory result is obtained by comparing it with 51Cr release method. It demonstrates that the new marker provides an alternative to currently used radioactive markers for the assessment of in vitro cellular cytotoxicity.

  3. Resazurin Live Cell Assay: Setup and Fine-Tuning for Reliable Cytotoxicity Results. (United States)

    Rodríguez-Corrales, José Á; Josan, Jatinder S


    In vitro cytotoxicity tests allow for fast and inexpensive screening of drug efficacy prior to in vivo studies. The resazurin assay (commercialized as Alamar Blue(®)) has been extensively utilized for this purpose in 2D and 3D cell cultures, and high-throughput screening. However, improper or lack of assay validation can generate unreliable results and limit reproducibility. Herein, we report a detailed protocol for the optimization of the resazurin assay to determine relevant analytical (limits of detection, quantification, and linear range) and biological (growth kinetics) parameters, and, thus, provide accurate cytotoxicity results. Fine-tuning of the resazurin assay will allow accurate and fast quantification of cytotoxicity for drug discovery. Unlike more complicated methods (e.g., mass spectrometry), this assay utilizes fluorescence spectroscopy and, thus, provides a less costly alternative to observe changes in the reductase proteome of the cells.

  4. Mathematical Modeling of Cytotoxic Lymphocyte-Mediated Immune Response to Hepatitis B Virus Infection

    Directory of Open Access Journals (Sweden)

    Changjiang Long


    Full Text Available Nowak's model of the human immunodeficiency virus (HIV infection has been extensively and successfully used to simulate the interaction between HIV and cytotoxic lymphocyte- (CTL- mediated immune response. However, this model is not available for hepatitis B virus (HBV infection. As the enhanced recruitment of virus-specific CTLs into the liver has been an important novel concept in the pathogenesis of hepatitis B, we develop a specific mathematical model analyzing the relationship between HBV and the CTL-mediated immune response, and the indicator of the liver cell damage, alanine aminotransferase (ALT. The stability condition of the complete recovery equilibrium point at which HBV will be eliminated entirely from the body is discussed. A different set of parameters is used in the simulation, and the results show that the model can interpret the wide variety of clinical manifestations of HBV infection. The model suggests that a rapid and vigorous CTL response is required for resolution of HBV infection.

  5. Specific cytotoxic T lymphocyte responses in Chinese HIV/AIDS patients

    Institute of Scientific and Technical Information of China (English)

    尚红; 韩晓旭; 王亚男; 周立平; 张子宁; 姜拥军; 张旻; 于旭


    Human immunodeficiency virus type 1 (HIV-1)-specific cytotoxic T lymphocytes (CTL) are considered to play a central role in the immune response against HIV-1. During untreated acute HIV-1 infection, virus-specific CTL activity is associated with the initial decrease in viremia.1 After HIV infection, those individuals with a slow progressive course develop stronger CTL responses than those with typical disease progression.2,3 Restoring HIV-1-specific CTL responses have been considered a key factor in immune reconstitution and vaccine development. Here we present the analysis of HIV-1 Gag-specific CTL responses in 23 Chinese HIV/AIDS cases in order to take the initial steps at identifying the epitopes that dominate the CTL response in Chinese patients.

  6. Posttranscriptional clearance of hepatitis B virus RNA by cytotoxic T lymphocyte-activated hepatocytes. (United States)

    Tsui, L V; Guidotti, L G; Ishikawa, T; Chisari, F V


    Using transgenic mice that replicate the hepatitis B virus (HBV) genome, we recently demonstrated that class I-restricted, hepatitis B surface antigen-specific cytotoxic T lymphocytes (CTLs) can noncytolytically eliminate HBV pregenomic and envelope RNA transcripts from the hepatocyte. We now demonstrate that the steady-state content of these viral transcripts is profoundly reduced in the nucleus and cytoplasm of CTL-activated hepatocytes, but their transcription rates are only slightly reduced. Additionally, we demonstrate that transcripts covering the HBV X coding region are resistant to downregulation by the CTL. These results imply the existence of CTL-inducible hepatocellular factors that interact with a discrete element(s) between nucleotides 3157 and 1239 within the viral pregenomic and envelope transcripts and mediate their degradation, thus converting the hepatocyte from a passive victim to an active participant in the host response to HBV infection. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8618909

  7. An automated flow cytometric micronucleus assay for human lymphocytes. (United States)

    Schreiber, G A; Beisker, W; Braselmann, H; Bauchinger, M; Bögl, K W; Nüsse, M


    A new flow cytometric method is presented for scoring micronuclei (MN) in human lymphocytes after in vitro gamma-irradiation. Fifty to fifty-five hours after PHA-stimulation, the frequency of micronuclei per nucleus and the fraction of cells in the second cell cycle were measured using flow cytometry. All data were automatically analysed using our DAS-software package. Eight individual linear-quadratic dose response curves derived from five donors revealed inter- and intra-individual variabilities of all curve parameters. Since also an age dependence was found for spontaneous MN-frequencies and for the linear curve parameter, a combined linear-quadratic age-dose-effect model was used to fit the data. The 90% prediction intervals show that a reliable individual dose estimation for donors aged between 23 and 54 years cannot be achieved for exposures below 1 Gy.

  8. Virus elimination in acute lymphocytic choriomeningitis virus infection. Correlation with virus-specific delayed-type hypersensitivity rather than cytotoxicity

    DEFF Research Database (Denmark)

    Thomsen, Allan Randrup; Volkert, M; Bro-Jørgensen, K


    The immunological effector mechanism responsible for the elimination of virus in murine acute non-fatal extracranial lymphocytic choriomeningitis virus infection was studied. In this infection virus clearance is generally regarded as the result of a direct action of virus-specific cytotoxic T cells...

  9. Specific induction of anti-leukemia effects by umbilical cord cell-derived CD8~+ T cytotoxic lymphocytes

    Institute of Scientific and Technical Information of China (English)



    Objective To explore the specific anti-leukemia immune response of CD8+ cytotoxic T lymphocyte (CTL) derived from cord blood (CB) ex vivo and evaluate the feasibilities and values of the CTL for specific immunotherapy. Methods Dendritic cells (DC) were induced from mononuclear cells (MNC) by combination cytokines in 10 CB samples. Loading U937 cell lysate antigen on

  10. Human infection with Trypanosoma cruzi induces parasite antigen-specific cytotoxic T lymphocyte responses. (United States)

    Wizel, B; Palmieri, M; Mendoza, C; Arana, B; Sidney, J; Sette, A; Tarleton, R


    Experimental models of Chagas' disease, an infection caused by the intracellular protozoan Trypanosoma cruzi, have demonstrated the crucial immunoprotective role played by CD8(+) T lymphocytes. These cells dominate inflammatory foci in parasitized tissues and their elimination from mice leads to uncontrolled parasite replication and subsequent death of the infected host. A trypomastigote surface antigen, TSA-1, and two amastigote surface molecules, ASP-1 and ASP-2, were recently identified as targets of CD8(+) cytotoxic T lymphocytes (CTL) in T. cruzi-infected mice. Until now, however, there was no evidence for the development of parasite-specific CTL in T. cruzi-infected humans. In this study, human CTL specific for TSA-1-, ASP-1-, and ASP-2-derived peptides were detected in the peripheral blood mononuclear cells from 21 of 24 HLA-A2(+) T. cruzi-infected patients. CTL recognition was antigen specific, A2-restricted, and CD8(+) T cell-dependent. Demonstration of human CTL against T. cruzi and against target molecules identified using the murine model provides important information for the optimal design and evaluation of vaccines to prevent or ameliorate Chagas' disease.

  11. Monitoring of WT1-specific cytotoxic T lymphocytes after allogeneic hematopoietic stem cell transplantation. (United States)

    Morita, Yuriko; Heike, Yuji; Kawakami, Mami; Miura, Osamu; Nakatsuka, Shin-Ichi; Ebisawa, Michiko; Mori, Shin-Ichiro; Tanosaki, Ryuji; Fukuda, Takahiro; Kim, Sung-Won; Tobinai, Kensei; Takaue, Yoichi


    Donor-derived cytotoxic T lymphocytes (CTL) that respond to tumor antigens emerge after hematopoietic stem cell transplantation (HSCT), particularly in association with the status of immune recovery. To analyze the frequency of CTL against PR1, PRAME and WT1 after HSCT, a tetramer-based analysis was performed in 97 samples taken from 35 patients (9 AML, 11 MDS, 2 CML, 4 ALL, 7 lymphoma and 2 renal cell carcinoma [RCC]) with the HLA-A02 phenotype. Regarding PR1, only 1 sample showed the presence of tetramer-positive cells (0.04%/lymphocyte). Similarly, in PRAME, only 10 of 97 samples were sporadically positive with low titers. For WT1, positive results were detected in 39 of 97 samples and 7 (2 CML, 1 ALL, 2 lymphoma and 2 RCC) patients clearly showed positive results more than once. On the basis of these results, we performed serial analyses of WT1-specific CTL during the clinical course in 2 patients with RCC, who underwent HSCT with a reduced-intensity regimen, to examine the precise correlation between the kinetics of CTL, the occurrence of GVHD and the observed clinical response. A higher positive rate for WT1-specific CTL and a correlation with the clinical response suggest that WT1 may be a useful antigen for a wider monitoring application.

  12. Human immunodeficiency virus type 1 infection of antigen-specific CD4 cytotoxic T lymphocytes. (United States)

    Robbins, P A; Roderiquez, G L; Peden, K W; Norcross, M A


    The effect of macrophage (M)-tropic and T cell line (T)-tropic human immunodeficiency virus type 1 (HIV-1) infection on antigen-specific CD4 cytotoxic T lymphocytes (CTLs) has been studied using a CD4 CTL line specific for a peptide from influenza B virus hemagglutinin. In the absence of antigen presentation, the production of CC chemokines was low. Both the M-tropic HIV-1 strain (HIV-1AD) and the T-tropic HIV-1 strain (HIV-1LAI) established productive infections in the CD4 CTLs, decreasing antigen-specific cytotoxicity. Peptide presented to the CD4 CTLs increased their secretion of RANTES and MIP-1beta, suppressed M-tropic HIV-1 replication, downmodulated CCR5 expression, and preserved CTL recognition. The suppression of M-tropic HIV-1 replication and downmodulation of the CCR5 receptor likely resulted from CC chemokine secretion since antibodies to CC chemokines restored M-tropic HIV-1 replication. Antigen presentation did not protect CD4 CTLs from T-tropic HIV-1 infection or preserve their CTL recognition. Thus, these CD4 CTLs do not make suppressor factors that inhibit the T-tropic HIV-1LAI isolate. The results indicate that these CD4 CTLs can either harbor or suppress M-tropic HIV-1 infection, depending on whether antigen is present. CD4 CTLs might therefore provide some protection in the early stages of HIV-1 infection when M-tropic isolates are present.

  13. A general functional response of cytotoxic T lymphocyte-mediated killing of target cells. (United States)

    Gadhamsetty, Saikrishna; Marée, Athanasius F M; Beltman, Joost B; de Boer, Rob J


    Cytotoxic T lymphocytes (CTLs) kill virus-infected cells and tumor cells, and play a critical role in immune protection. Our knowledge of how the CTL killing efficiency varies with CTL and target cell numbers is limited. Here, we simulate a region of lymphoid tissue using a cellular Potts model to characterize the functional response of CTL killing of target cells, and find that the total killing rate saturates both with the CTL and the target cell densities. The relative saturation in CTL and target cell densities is determined by whether a CTL can kill multiple target cells at the same time, and whether a target cell can be killed by many CTLs together. We find that all the studied regimes can be well described by a double-saturation (DS) function with two different saturation constants. We show that this DS model can be mechanistically derived for the cases where target cells are killed by a single CTL. For the other cases, a biological interpretation of the parameters is still possible. Our results imply that this DS function can be used as a tool to predict the cellular interactions in cytotoxicity data.

  14. Hitchhiking nanoparticles: Reversible coupling of lipid-based nanoparticles to cytotoxic T lymphocytes. (United States)

    Wayteck, Laura; Dewitte, Heleen; De Backer, Lynn; Breckpot, Karine; Demeester, Jo; De Smedt, Stefaan C; Raemdonck, Koen


    Following intravenous injection of anti-cancer nanomedicines, many barriers need to be overcome en route to the tumor. Cell-mediated delivery of nanoparticles (NPs) is promising in terms of overcoming several of these barriers based on the tumoritropic migratory properties of particular cell types. This guided transport aims to enhance the NP accumulation in the tumor and moreover enhance the infiltration of regions that are typically inaccessible for free NPs. Within this study, cytotoxic CD8(+) T cells were selected as carriers based on both their ability to migrate to the tumor and their intrinsic cytolytic activity against tumor cells. Many anti-cancer nanomedicines require tumor cell internalization to mediate cytosolic drug delivery and enhance the anti-cancer effect. This proof-of-concept therefore reports on the reversible attachment of liposomes to the surface of cytotoxic T lymphocytes via a reduction sensitive coupling. The activation status of the T cells and the liposome composition are shown to strongly influence the loading efficiency. Loading the cells with liposomes does not compromise T cell functionalities like proliferation and cytolytic function. Additionally, the triggered liposome release is demonstrated upon the addition of glutathione. Based on this optimization using liposomes as model NPs, a small interfering RNA (siRNA)-loaded NP was developed that can be coupled to the surface of CD8(+) T cells.

  15. Protective Effect of Prolactin against Methylmercury-Induced Mutagenicity and Cytotoxicity on Human Lymphocytes

    Directory of Open Access Journals (Sweden)

    Liz Carmem Silva-Pereira


    Full Text Available Mercury exhibits cytotoxic and mutagenic properties as a result of its effect on tubulin. This toxicity mechanism is related to the production of free radicals that can cause DNA damage. Methylmercury (MeHg is one of the most toxic of the mercury compounds. It accumulates in the aquatic food chain, eventually reaching the human diet. Several studies have demonstrated that prolactin (PRL may be differently affected by inorganic and organic mercury based on interference with various neurotransmitters involved in the regulation of PRL secretion. This study evaluated the cytoprotective effect of PRL on human lymphocytes exposed to MeHg in vitro, including observation of the kinetics of HL-60 cells (an acute myeloid leukemia lineage treated with MeHg and PRL at different concentrations, with both treatments with the individual compounds and combined treatments. All treatments with MeHg produced a significant increase in the frequency of chromatid gaps, however, no significant difference was observed in the chromosomal breaks with any treatment. A dose-dependent increase in the mitotic index was observed for treatments with PRL, which also acts as a co-mitogenic factor, regulating proliferation by modulating the expression of genes that are essential for cell cycle progression and cytoskeleton organization. These properties contribute to the protective action of PRL against the cytotoxic and mutagenic effects of MeHg.

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

    Directory of Open Access Journals (Sweden)

    Song C


    Full Text Available Chanyoung Song,* Young-Woock Noh,* Yong Taik Lim SKKU Advanced Institute of Nanotechnology (SAINT, School of Chemical Engineering, Sungkyunkwan University, Suwon, South Korea *These authors contributed equally to this work Abstract: Effective induction of an antigen-specific cytotoxic T lymphocyte (CTL immune response is one of the key goals of cancer immunotherapy. We report the design and fabrication of polyethylenimine (PEI-coated polymer nanoparticles (NPs as efficient antigen-delivery carriers that can induce antigen cross-presentation and a strong CTL response. After synthesis of poly(d,l-lactide-co-glycolide (PLGA NPs containing ovalbumin (OVA by the double-emulsion solvent-evaporation method, cationic-charged PLGA NPs were generated by coating them with PEI. In a methyl tetrazolium salt assay, no discernible cytotoxic effect of PEI-coated PLGA (OVA NPs was observed. The capacity and mechanism of PEI-coated PLGA (OVA NPs for antigen delivery and cross-presentation on dendritic cells (DCs were determined by fluorescence microscopy and flow cytometry. PEI-coated PLGA (OVA NPs were internalized efficiently via phagocytosis or macropinocytosis in DCs and induced efficient cross-presentation of the antigen on MHC class I molecules via both endosome escape and a lysosomal processing mechanism. The DCs treated with PEI-coated PLGA (OVA NPs induced a release of IL-2 cytokine from OVA-specific CD8-OVA1.3 T cells more efficiently than DCs treated with PLGA (OVA NPs. Therefore, the PEI-coated PLGA (OVA NPs can induce antigen cross-presentation and are expected to be used for induction of a strong CTL immune response and for efficient anticancer immunotherapy. Keywords: antigen delivery, dendritic cells, polymer NPs, vaccine, cross-presentation

  17. Measuring cytotoxicity by bioluminescence imaging outperforms the standard chromium-51 release assay.

    Directory of Open Access Journals (Sweden)

    Mobin A Karimi

    Full Text Available The chromium-release assay developed in 1968 is still the most commonly used method to measure cytotoxicity by T cells and by natural killer cells. Target cells are loaded in vitro with radioactive chromium and lysis is determined by measuring chromium in the supernatant released by dying cells. Since then, alternative methods have been developed using different markers of target cell viability that do not involve radioactivity. Here, we compared and contrasted a bioluminescence (BLI-based cytotoxicity assay to the standard radioactive chromium-release assay using an identical set of effector cells and tumor target cells. For this, we stably transduced several human and murine tumor cell lines to express luciferase. When co-cultured with cytotoxic effector cells, highly reproducible decreases in BLI were seen in an effector to target cell dose-dependent manner. When compared to results obtained from the chromium release assay, the performance of the BLI-based assay was superior, because of its robustness, increased signal-to-noise ratio, and faster kinetics. The reduced/delayed detection of cytotoxicity by the chromium release method was attributable to the association of chromium with structural components of the cell, which are released quickly by detergent solubilization but not by hypotonic lysis. We conclude that the (BLI-based measurement of cytotoxicity offers a superior non-radioactive alternative to the chromium-release assay that is more robust and quicker to perform.

  18. Dose assessment intercomparisons within the RENEB network using G0-lymphocyte prematurely condensed chromosomes (PCC assay)


    Terzoudi, Georgia I; Pantelias, Gabriel; Darroudi, Firouz; Barszczewska, Katarzyna; Buraczewska, Iwona; Depuydt, Julie; Georgieva, Dimka; Hadjidekova, Valeria; Hatzi, Vasiliki I.; Karachristou, Ioanna; Karakosta, Maria; Meschini, Roberta; M’kacher, Radhia; Montoro, Alegria; Palitti, Fabrizio


    Purpose: Dose assessment intercomparisons within the RENEB network were performed for triage biodosimetry analyzing G0-lymphocyte PCC for harmonization, standardization and optimization of the PCC assay. Materials and methods: Comparative analysis among different partners for dose assessment included shipment of PCC-slides and captured images to construct dose-response curves for up to 6 Gy c-rays. Accident simulation exercises were performed to assess the suitability of the PCC assay by d...

  19. Cytotoxic T lymphocyte activity and CD8 subpopulations in children at risk of HIV infection. (United States)

    Aldhous, M C; Watret, K C; Mok, J Y; Bird, A G; Froebel, K S


    HIV-specific cytotoxic T lymphocytes (CTL) are thought to play a major role in viral control in HIV-infected adults. Changes in the relative proportions of CD8 lymphocyte subpopulations are also thought to be associated with disease progression. Less is known about the relative effectiveness of CTL against different HIV targets, or about the relationship, if any, between CTL activity and CD8 subpopulations. We have measured CTL activity against four HIV gene products (gag, tat, pol and env) and expression of CD45RO, CD45RA, HLA-DR, CD29, S6F1, and CD57 surface markers on CD8 cells from nine HIV-infected and 11 HIV-uninfected children. Of nine HIV-infected children, six showed antigen-specific CTL activity on at least one occasion: 4/6 directed against tat, 6/6 against pol, 1/6 against env, and 1/6 against gag. However, the specificity of the CTL activity varied between children and within individual children with time. Furthermore, two uninfected children showed CTL activity, one to HIV-gag, -pol and -tat, and the other to HIV-pol. All the HIV-infected and two uninfected children had abnormal proportions of CD8 subpopulations in whole blood compared with age-matched controls. There was no correlation between CTL activity and CD8 subsets in whole blood. Five children changed from CTL-positive to CTL-negative (or vice versa) during the study. In these, the occasions when CTL activity was detected coincided with an increase in CD8 cells, an expansion of HLA-DR+ CD8 cells and a loss of CD45RA+ CD8 cells.

  20. Demethylating agent decitabine induces autologous cancer testis antigen specific cytotoxic T lymphocytes in vivo

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ji-hao; YAO Yu-shi; WANG Li-xin; WANG Jia; LI Yong-hui; JIANG Meng-meng; ZHOU Min-hang


    Background Cancer testis antigens (CTAs) are a novel group of tumor associated antigens.Demethylating agent decitabine was reported to be able to up-regulate CTAs through its hypomethylation mechanism,thus enhance the immunogenicity of leukemia cells.However,few researches have ever focused on the questions that whether this immunostimulatory effect of decitabine could induce autologous CTA specific cytotoxic T lymphocytes (CTLs) in vivo,and if so,whether this effect contributes to disease control.In this study,we aimed to show that decitabine could induce specific autologous CTLs against some mouse CTAs in leukemia cells in vitro and in vivo.Methods Several mouse CTAs were screened by RT-PCR.CTL specific to one of the CTAs named P1A was detected and sorted by P1A specific dimer by flow cytometry.The activity of specific CTLs was measured by real time RT-PCR.Results We firstly screened expression of some CTAs in mouse leukemia cells before and after decitabine treatment and found that decitabine treatment did up-regulate expression of many CTAs.Then we measured the CTLs' activity specific to a mouse CTA P1A in vivo and showed that this activity increased after decitabine treatment.Finally,we sorted these in vivo induced P1A specific CTLs by flow cytometry and demonstrated their cytotoxicity against decitabine treated leukemia cells.Conclusions Our study showed the autologous immune response induced by decitabine in vivo.And more importantly,we firstly proved that this response may contribute to disease control.We believe that this immunostimulatory effect is another anti-cancer mechanism of decitabine,and this special effect would inspire new applications of decitabine in the field of leukemia treatment in the future.

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


    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

  2. Cytotoxic T-lymphocyte antigen 4 gene polymorphisms and susceptibility to chronic hepatitis B

    Institute of Scientific and Technical Information of China (English)

    Amir Houshang Mohammad Alizadeh; Mehrdad Hajilooi; Mitra Ranjbar; Farahnaz Fallahian; Seyed Mohsen Mousavi


    AIM: To assess the three polymorphism regions within cytotoxic T-lymphocyte antigen 4 (CTLA-4) gene, a C/T base exchange in the promoter region-318 (CTLA-4 -318C/T), an A/G substitution in the exon 1 position 49 (CTLA-4 49A/G), a T/C substitution in 1172 (CTLA-4 -1172T/C) in patients with chronic hepatitis B.METHODS: Fifty-one patients with chronic hepatitis B virus infection and 150 healthy subjects were recruited sequentially as they presented to the hepatic clinic. Classification of chronic hepatitis B virus (HBV)-infected patients was as asymptomatic carrier state (26 patients) and chronic hepatitis B (25 patients). Genomic DNA was isolated from anti-coagulated peripheral blood Buffy coat using Miller's salting-out method. The presence of the CTLA-4 gene polymorphisms was determined using polymerase chain reaction amplification refractory mutation system (ARMS).RESULTS: We observed a significant association between -318 genotypes frequency (T+C-, T+C+, T-C+) and susceptibility to chronic hepatitis B (P=0.012,OR=0.49, 95%CI: 0.206-1.162). However, we did not observe a significant association for +49 genotype frequency (T+C+, T+C- T-C+) and -1172 genotype frequency (C+T+, T+C- C+T-) and state of disease.CONCLUSION: Our results suggest that CTLA-4 gene polymorphisms may partially be involved in the susceptibility to chronic hepatitis B.

  3. Tissue Dimensionality Influences the Functional Response of Cytotoxic T Lymphocyte-Mediated Killing of Targets. (United States)

    Gadhamsetty, Saikrishna; Marée, Athanasius F M; de Boer, Rob J; Beltman, Joost B


    Cytotoxic T lymphocyte (CTL)-mediated killing of virus infections and tumors occurs over a wide range of conditions. The spatial environments in which CTLs encounter target cells vary from narrow vessels, to two-dimensional epithelial tissues, to densely populated 3-dimensional (3D) T cell areas within lymphoid tissues. How such spatial environments alter the functional response of CTL-mediated killing, i.e., how the killing efficiency depends on cell densities, is unclear. In this study, we perform cellular Potts model simulations in different spatial configurations to investigate how the dimensionality of the space affects the functional response of CTL-mediated killing. Irrespective of the spatial configuration, the function with separate saturation constants for CTL and for target cell densities that we previously proposed can in all cases describe the response, demonstrating its generality. However, the tissue dimensionality determines at which cell densities the killing rate starts to saturate. We show that saturation in a fully 3D environment is stronger than in a "flat" 3D environment, which is largely due to accompanying differences in the CTL-target encounter rates.

  4. Human heat shock protein-specific cytotoxic T lymphocytes display potent antitumour immunity in multiple myeloma (United States)

    Li, Rong; Qian, Jianfei; Zhang, Wenhao; Fu, Weijun; Du, Juan; Jiang, Hua; Zhang, Hui; Zhang, Chunyang; Xi, Hao; Yi, Qing; Hou, Jian


    Tumour cell–derived heat shock proteins (HSPs) are used as vaccines for immunotherapy of cancer patients. However, it is proposed that the peptide chaperoned on HSPs, not HSPs themselves, elicited a potent immune response. Given that HSPs are highly expressed by most myeloma cells and vital to myeloma cell survival, we reasoned that HSPs themselves might be an ideal myeloma antigen. In the present study, we explored the feasibility of targeting HSPs themselves for treating multiple myeloma. We identified and chose HLA-A*0201-binding peptides from human HSPB1 (HSP27) and HSP90AA1 (HSP90), and confirmed their immunogenicity in HLA-A*0201 transgenic mice. Dendritic cells pulsed with HSPB1 and HSP90AA1 peptides were used to stimulate peripheral blood mononuclear cells from healthy volunteers and myeloma patients to generate HSP peptide-specific cytotoxic T lymphocytes (CTLs). HSP peptide-specific CTLs efficiently lysed HLA-A*0201+ myeloma cells (established cell lines and primary plasma cells) but not HLA-A*0201− myeloma cells in vitro, indicating that myeloma cells naturally express HSP peptides in the context of major histocompatibility complex class I molecules. More importantly, HSP peptide-specific CTLs effectively reduced tumour burden in the xenograft mouse model of myeloma. Our study clearly demonstrated that HSPs might be novel tumour antigens for immunotherapy of myeloma. PMID:24824351

  5. Evaluation of cytotoxic and genotoxic activity of fungicide formulation Tango(®) Super in bovine lymphocytes. (United States)

    Schwarzbacherová, Viera; Wnuk, Maciej; Lewinska, Anna; Potocki, Leszek; Zebrowski, Jacek; Koziorowski, Marek; Holečková, Beáta; Šiviková, Katarína; Dianovský, Ján


    Tango(®) Super is a two-compound fungicide formulation widely employed in grain protection. However, details of Tango(®) Super effects on cell cultures have not been fully investigated. In this study, bovine lymphocytes were exposed to a concentration range 0.5; 1.5; 3; 6; and 15 μg mL(-1) for 4 h to assess the cytotoxicity and genotoxicity of the fungicide. Our experiments revealed that this fungicide treatment reduced cell viability, decreased cell proliferation and provoked apoptotic cell death. Cell cycle analysis showed predominant accumulation of cells in the G0/G1 phase of the cell cycle. The fungicide was able to induce mitochondrial superoxide production accompanied by elevated levels of carbonylated proteins and changes in the lipid membrane composition. The fungicide did not induce micronuclei production, but stimulated both DNA double-strand breaks and the formation of p53 binding protein, which is accumulated during the DNA repair process at the site of double-strand breaks. Based on the obtained data we suppose that the fungicide-induced DNA damage is the result of oxidative stress, which may contribute to higher occurrence of apoptotic cell death. Because ergosterol biosynthesis-inhibiting fungicides are widely used in agriculture to ensure higher crop yields and may cause health impairment of animals and humans, there is a need for further testing to elucidate their potential genotoxic effects using in vivo and/or in vitro systems.

  6. Consequences of cytotoxic T lymphocyte interaction with major histocompatibility complex class I-expressing neurons in vivo



    Neurons have evolved strategies to evade immune surveillance that include an inability to synthesize the heavy chain of the class I major histocompatibility complex (MHC), proteins that are necessary for cytotoxic T lymphocyte (CTL) recognition of target cells. Multiple viruses have taken advantage of the lack of CTL-mediated recognition and killing of neurons by establishing persistent neuronal infections and thereby escaping attack by antiviral CTL. We have expressed a class I MHC molecule ...

  7. Immunoregulation through IL-10 gene expression and the fate of cytotoxic T lymphocyte-mediated tumor immunotherapy

    Directory of Open Access Journals (Sweden)

    Chakraborty Nitya


    Full Text Available Gene analysis of tumor associated antigens revealed that tumor antigens are all normal gene product. Inducing tumor reactive cytotoxic T lymphocytes (CT in the patients is same as inducing autoimmunity in the patients. Immunosuppressive cytokine interleukin-10 (IL-10 plays an important role in maintaining homeostasis or tolerance. To break the tumor tolerance, blocking and IL-10 secretion or intervention in the pathways of IL-10 gene activation is indeed important.

  8. Clinical-Grade Human Multipotent Adult Progenitor Cells Block CD8+ Cytotoxic T Lymphocytes. (United States)

    Plessers, Jeroen; Dekimpe, Emily; Van Woensel, Matthias; Roobrouck, Valerie D; Bullens, Dominique M; Pinxteren, Jef; Verfaillie, Catherine M; Van Gool, Stefaan W


    : MultiStem cells are clinical-grade multipotent adult bone marrow-derived progenitor cells (MAPCs), with extensive replication potential and broader differentiation capacity compared with mesenchymal stem cells. Human MAPCs suppress T-cell proliferation induced by alloantigens and mutually interact with allogeneic natural killer cells. In this study, the interaction between MultiStem and CD8(+) cytotoxic T lymphocytes (CTLs) was addressed for the first time. In an in vitro setting, the immunogenicity of MultiStem, the susceptibility of MultiStem toward CTL-mediated lysis, and its effects on CTL function were investigated. MultiStem was nonimmunogenic for alloreactive CTL induction and was-even after major histocompatibility complex class I upregulation-insensitive to alloantigen-specific CTL-mediated lysis. Furthermore, MultiStem reduced CTL proliferation and significantly decreased perforin expression during the T-cell activation phase. As a consequence, MultiStem dose-dependently impaired the induction of CTL function. These effects of MultiStem were mediated predominantly through contact-dependent mechanisms. Moreover, MultiStem cells considerably influenced the expression of T-cell activation markers CD25, CD69, and human leukocyte antigen-DR. The MultiStem-induced CD8(-)CD69(+) T-cell population displayed a suppressive effect on the induction of CTL function during a subsequent mixed-lymphocyte culture. Finally, the killer activity of activated antigen-specific CTLs during their cytolytic effector phase was also diminished in the presence of MultiStem. This study confirms that these clinical-grade MAPCs are an immune-modulating population that inhibits CTL activation and effector responses and are, consequently, a highly valuable cell population for adoptive immunosuppressive therapy in diseases where damage is induced by CTLs. Because multipotent adult progenitor cells (MAPCs) are among the noteworthy adult mesenchymal stem cell populations for immune

  9. Fabrication, in vitro Degradation and Cytotoxic Assay of Different Cystalline Phases Calcium Polyphosphate

    Institute of Scientific and Technical Information of China (English)


    Fabrication, in vitro degradation and cytotoxic assay of different crystalline phases calcium polyphosphate (CPP) were reported. The CPP ceramics were fabricated by crystallizing the amorphous frits , and sintered at 550 ℃ ,875 ℃ ,1000 ℃ for 1 h to obtain the γ-CPP, β-CPP anda-CPP respectively. The effects of the different crystalline phases on their weight loss and released PO4 3- were investigated during the degradation.And the surface change was observed by the SEM. The osteoblastic ROS17/2.8 cell line was used to estimate the cytotoxicity of CPP. The effects of CPP on cells' proliferation were evaluated by using MTT assay. The experimental results showed that γ-CPP, β- CPP and α-CPP did not exert cytotoxic effect on the cells. In addition, the proliferation of the growth of ROS17/2.8 cells on β-CPP was optimal.

  10. DNA strand breaks (comet assay) in blood lymphocytes from wild bottlenose dolphins. (United States)

    Lee, Richard F; Bulski, Karrie; Adams, Jeffrey D; Peden-Adams, Margie; Bossart, Gregory D; King, Lydia; Fair, Patricia A


    The comet assay was carried out on blood lymphocytes from a large number of wild dolphins (71 from Indian River Lagoon, FL, USA; 51 from Charleston Harbor, SC, USA) and provides a baseline study of DNA strand breaks in wild dolphin populations. There were no significant differences in the comet assay (% DNA in tail) results between the different age and sex categories. Significant difference in DNA strand breaks were found between Charleston Harbor dolphins (median--17.4% DNA in tail) and Indian River Lagoon dolphins (median--14.0% DNA in tail). A strong correlation found between T-cell proliferation and DNA strand breaks in dolphin lymphocytes suggests that dolphins with a high numbers of DNA strand breaks have a decreased ability to respond to infection. Higher concentrations of genotoxic agents in Charleston Harbor compared with Indian River lagoon may have been one of the causes of higher DNA strand breaks in these dolphins.

  11. Artificial antigen-presenting cells plus IL-15 and IL-21 efficiently induce melanoma-specific cytotoxic CD8+CD28+ T lymphocyte responses

    Institute of Scientific and Technical Information of China (English)

    Xia Yu; Yuan Fang; Xi Li; Nuo Zhou; Yong-Xiang Zhao; Xiao-Ling Lu; Jian He; Sodaly Mongkhoune; Yi Peng; Yuan Xie; Jing Su; Su-Fang Zhou; Xiao-Xun Xie; Guo-Rong Luo


    To develop a novel artificial antigen-presenting system for efficiently inducing melanoma-specific CD8+CD28+ cytotoxic T lymphocyte (CTL) responses. Methods: Cell-sized Dynabeads® M-450 Epoxy beads coated with H-2Kb:Ig-TRP2180-188 and anti-CD28 antibody were used as artificial antigen-presenting cells (aAPCs) to induce melanoma-specific CD8+CD28+CTL responses with the help of IL-21 and IL-15. Dimer staining, proliferation, ELISPOT, and cytotoxicity experiments were conducted to evaluate the frequency and activity of induced CTLs. Results: Dimer staining demonstrated that the new artificial antigen-presenting system efficiently induced melanoma TRP2-specific CD8+CD28+ CTLs. Proliferation and ELISPOT assays indicated that the induced CTLs rapidly proliferate and produce increased IFN-γ under the stimulation of H-2Kb:Ig-TRP2-aAPCs, IL-15, and IL-21. In addition, cytotoxicity experiments showed that induced CTLs have specific killing activity of target cells. Conclusions: The new artificial antigen-presenting system including aAPCs plus IL-21 and IL-15 can induce a large number of antigen-specific CD8+CD28+ CTLs against the melanoma. Our study provides evidence for a novel adoptive immunotherapy against tumors.

  12. Paraflagellar rod protein-specific CD8+ cytotoxic T lymphocytes target Trypanosoma cruzi-infected host cells. (United States)

    Wrightsman, Ruth A; Luhrs, Keith A; Fouts, David; Manning, Jerry E


    Our previous studies show that in mice immunized with the paraflagellar rod (PFR) proteins of Trypanosoma cruzi protective immunity against this protozoan parasite requires MHC class I-restricted T cell function. To determine whether PFR-specific CD8+ T cell subsets are generated during T. cruzi infection, potential CTL targets in the PFR proteins were identified by scanning the amino acid sequences of the four PFR proteins for regions of 8-10 amino acids that conform to predicted MHC class I H-2b binding motifs. A subset of the peptide sequences identified were synthesized and tested as target antigen in 51Cr-release assays with effector cells from chronically infected T. cruzi mice. Short-term cytotoxic T lymphocyte (CTL) lines specific for two of the peptides, PFR-1(164-171) and PFR-3(123-130), showed high levels of lytic activity against peptide-pulsed target cells, secreted interferon (IFN)-gamma in response to parasite-infected target cells, and were found to be CD8+, CD4-, CD3+, TCRalphabeta+ cells of the Tc1 subset. Challenge of PFR immunized CD8-/- and perforin-deficient (PKO) mice confirmed that while CD8+ cells are required for survival of T. cruzi challenge infection, perforin activity is not required. Furthermore, while lytic activity of PFR-specific CD8+ T cell lines derived from PKO mice was severely impaired, the IFN-gamma levels secreted by CTLs from PKO mice were equivalent to that of normal mice, suggesting that the critical role played by CD8+ T cells in immunity to the parasite may be secretion of type 1 cytokines rather than lysis of parasite infected host cells.

  13. Identification of Melanoma-specific Peptide Epitopes by HLA-A2.1-restricted Cytotoxic T Lymphocytes

    Institute of Scientific and Technical Information of China (English)

    Hai-Liang GE; Ying WANG; Shu-Jun WANG; Yong ZHANG


    HLA-A2.1-associated peptides, extracted from human melanoma cells, were used to study epitopes for melanoma-specific HLA-A2.1-restricted cytotoxic T lymphocytes (CTLs) by epitope reconstitution, active peptide sequence characterization and synthetic peptide verification. CTL were generated from tumor-involved nodes by in vitro stimulation, initially with autologous melanoma cells and subsequently with allogeneic HLA-A2.1 positive melanoma cells. The CTLs could lyse autologous and allogeneic HLA-A2.1 positive melanomas, but not HLA-A2.1 negative melanomas or HLA-A2.1 positive non-melanomas. The lysis of melanomas could be inhibited by anti-CD3, anti-HLA class Ⅰ and anti-HLA-A2.1 monoclonal antibodies.HLA-A2.1 molecules were purified from detergent-solubilized human melanoma cells by immunoaffinity column chromatography and further fractionated by reversed phase high performance liquid chromatography.The fractions were assessed for their ability to reconstitute melanoma-specific epitopes with HLA-A2.1 positive antigen-processing mutant T2 cells. Three reconstitution peaks were observed in lactate dehydrogenase release assay. Mass spectrometry and ion-exchange high performance liquid chromatography analysis were used to identify peptide epitopes. Peptides with a mass-to-charge ratio of 948 usually consist of nine amino acid residues. The data from reconstitution experiments confirmed that the synthetic peptides contained epitopes and that the peptides associated with HLA-A2.1 and recognized by melanoma-specific CTL were present in these different melanoma cells. These peptides could be potentially exploited in novel peptide-based antitumor vaccines in immunotherapy for CTL.

  14. In vitro generation of human cytotoxic lymphocytes by virus. Viral glycoproteins induce nonspecific cell-mediated cytotoxicity without release of interferon. (United States)

    Casali, P; Sissons, J G; Buchmeier, M J; Oldstone, M B


    Purified hemagglutinin and fusion glycoproteins of measles virus either in soluble form or inserted in artifical membranes bind to human peripheral blood lymphocytes and induce cell-mediated cytotoxicity (CMC) in a dose-response fashion. Both autologous and heterologous noninfected target cells are lysed in vitro. The expression of CMC is not inhibited by anti-measles virus antibody added to lymphocytes previously exposed to viral glycoproteins. THe killer lymphocytes are Fc receptor positive, both erythrocyte-rosetting and non-erythrocyte-rosetting, as assessed by both positive and negative selection experiments. The induction of nonspecific CMC by viral glycoproteins either in the soluble state or inserted into artificial membranes could be segregated from the CMC associated with whole virions. First, on kinetics studies, purified viral glycoproteins induced CMC more rapidly than did whole virus. Second, viral glycoprotein-produced response occurred in the absence of detectable release of interferon into the culture medium, whereas CMC activity due to whole virions was associated with interferon release. The fact that purified measles virus glycoproteins integrated into artificial membrane bilayers were as efficient as their soluble counterparts in inducing CMC suggests that the hydrophobic portion of the glycoproteins was not involved in the induction and expression of the lytic activity. Purified glycoproteins from lymphocytic choriomeningitis virus behave similarly, although this virus is unrelated to measles virus. It is inferred that interferon-independent CMC induced by viral glycoproteins might account for some of the biological reactions occurring early in the control of a viral infection.

  15. Identification of Rhodococcus equi lipids recognized by host cytotoxic T lymphocytes (United States)

    Harris, Seth P.; Fujiwara, Nagatoshi; Mealey, Robert H.; Alperin, Debra C.; Naka, Takashi; Goda, Reina


    Immune adult horses have CD8+ cytotoxic T lymphocytes (CTLs) that recognize and lyse Rhodococcus equi-infected cells in an equine lymphocyte alloantigen (ELA)-A [classical major histocompatibility complex (MHC) class I]-unrestricted fashion. As protein antigens are MHC class I-restricted, the lack of restriction suggests that the bacterial antigens being recognized by the host are not proteins. The goals of this study were to test the hypothesis that these CTLs recognize unique R. equi cell-wall lipids related to mycobacterial lipids. Initial experiments showed that treatment of soluble R. equi antigen with broadly reactive proteases did not significantly diminish the ability of the antigen to stimulate R. equi-specific CTLs. R. equi-specific CTLs were also shown to lyse target cells (equine macrophages) pulsed with an R. equi lipid extract. Analysis of the R. equi lipid by TLC and MS (MALDI-TOF and ES) indicated that the extracted antigen consisted of three primary fractions: trehalose monomycolate (TMM), trehalose dimycolate (TDM) and cardiolipin (CL). ELA-A-mismatched cells pulsed with purified TMM and CL, but not the TDM fraction, were recognized and lysed by R. equi-specific CTLs. Because of their role in immune clearance and pathogenesis, transcription of the cytokines gamma interferon (IFN-γ) and interleukin-4 (IL-4) was also measured in response to R. equi lipids by using real-time PCR; elevated IFN-γ, but not IL-4, was associated with host clearance of the bacteria. The whole-cell R. equi lipid and all three R. equi lipid fractions resulted in marked increases in IFN-γ transcription, but no increase in IL-4 transcription. Together, these data support the hypothesis that immune recognition of unique lipids in the bacterial cell wall is an important component of the protective immune response to R. equi. The results also identify potential lipid antigens not previously shown to be recognized by CTLs in an important, naturally occurring actinomycete

  16. Real-Time Cytotoxicity Assay for Rapid and Sensitive Detection of Ricin from Complex Matrices (United States)

    Pauly, Diana; Worbs, Sylvia; Kirchner, Sebastian; Shatohina, Olena; Dorner, Martin B.; Dorner, Brigitte G.


    Background In the context of a potential bioterrorist attack sensitive and fast detection of functionally active toxins such as ricin from complex matrices is necessary to be able to start timely countermeasures. One of the functional detection methods currently available for ricin is the endpoint cytotoxicity assay, which suffers from a number of technical deficits. Methodology/Findings This work describes a novel online cytotoxicity assay for the detection of active ricin and Ricinus communis agglutinin, that is based on a real-time cell electronic sensing system and impedance measurement. Characteristic growth parameters of Vero cells were monitored online and used as standardized viability control. Upon incubation with toxin the cell status and the cytotoxic effect were visualized using a characteristic cell index–time profile. For ricin, tested in concentrations of 0.06 ng/mL or above, a concentration-dependent decrease of cell index correlating with cytotoxicity was recorded between 3.5 h and 60 h. For ricin, sensitive detection was determined after 24 h, with an IC50 of 0.4 ng/mL (for agglutinin, an IC50 of 30 ng/mL was observed). Using functionally blocking antibodies, the specificity for ricin and agglutinin was shown. For detection from complex matrices, ricin was spiked into several food matrices, and an IC50 ranging from 5.6 to 200 ng/mL was observed. Additionally, the assay proved to be useful in detecting active ricin in environmental sample materials, as shown for organic fertilizer containing R. communis material. Conclusions/Significance The cell-electrode impedance measurement provides a sensitive online detection method for biologically active cytotoxins such as ricin. As the cell status is monitored online, the assay can be standardized more efficiently than previous approaches based on endpoint measurement. More importantly, the real-time cytotoxicity assay provides a fast and easy tool to detect active ricin in complex sample matrices. PMID

  17. Cytotoxicity evaluation of Clinacanthus nutans through dimethylthiazol diphenyltetrazolium bromide and neutral red uptake assays


    Vajrabhaya, La-ongthong; Korsuwannawong, Suwanna


    Objectives: The aim of this study was to compare the results of dimethylthiazol diphenyltetrazolium bromide (MTT) and neutral red uptake (NRU) assays of Clinacanthus nutans cytotoxicity. Materials and Methods: Mouse fibroblast (L929) cells were exposed to 0.01%, 0.1%, 0.25%, and 0.5% (W/V) C. nutans in a 96-cluster-well-culture plate for 24 h. The cell viability after exposure to C. nutans was determined by MTT and NRU assays in separate tissue culture plates. The two assays were compared thr...

  18. A Sigmoid Functional Response Emerges When Cytotoxic T Lymphocytes Start Killing Fresh Target Cells. (United States)

    Gadhamsetty, Saikrishna; Marée, Athanasius F M; Beltman, Joost B; de Boer, Rob J


    Cytotoxic T lymphocyte (CTL)-mediated killing involves the formation of a synapse with a target cell, followed by delivery of perforin and granzymes. Previously, we derived a general functional response for CTL killing while considering that CTLs form stable synapses (i.e., single-stage) and that the number of conjugates remains at steady state. However, the killing of target cells sometimes requires multiple engagements (i.e., multistage). To study how multistage killing and a lack of steady state influence the functional response, we here analyze a set of differential equations as well as simulations employing the cellular Potts model, in both cases describing CTLs that kill target cells. We find that at steady state the total killing rate (i.e., the number of target cells killed by all CTLs) is well described by the previously derived double saturation function. Compared to single-stage killing, the total killing rate during multistage killing saturates at higher CTL and target cell densities. Importantly, when the killing is measured before the steady state is approached, a qualitatively different functional response emerges for two reasons: First, the killing signal of each CTL gets diluted over several targets and because this dilution effect is strongest at high target cell densities; this can result in a peak in the dependence of the total killing rate on the target cell density. Second, the total killing rate exhibits a sigmoid dependence on the CTL density when killing is a multistage process, because it takes typically more than one CTL to kill a target. In conclusion, a sigmoid dependence of the killing rate on the CTLs during initial phases of killing may be indicative of a multistage killing process. Observation of a sigmoid functional response may thus arise from a dilution effect and is not necessarily due to cooperative behavior of the CTLs. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  19. Cytotoxic T Lymphocyte Antigen-4 Gene Variants in Type 2 Diabetic Patients with or without Neuropathy

    Directory of Open Access Journals (Sweden)

    Javad Kiani


    Full Text Available Many studies have shown that cytotoxic T lymphocyte antigen-4 (CTLA-4 gene variants are associated with several autoimmune diseases particularly type 1 diabetes. Due to the lack of consistent data for this association with type 2 diabetes (T2D, this study explored the possible influence of CTLA-4 gene polymorphisms at -1722 (T/C, -318 (C/T, and +49 (G/A positions for susceptibility to T2D in relation with neuropathy. One hundred and eleven unrelated patients with T2D [49 patients with diabetic peripheral neuropathy (DPN and 62 patients without PDN] and 100 healthy ethnic- and gender-matched controls were included in this study. The dimorphisms at -1722 (C/T, -318 (C/T and +49 (A/G for CTLA-4 gene were determined using ARMS-PCR. The CTLA-4 (+49 G/G and (+49 A/A genotypes were found to be positively and negatively associated with T2D, respectively (p=0.03. The -318 C/T and T/T genotypes were more frequent in patients than controls and -318 C/C genotype was shown to be protective for T2D (p=0.003. ACT and GTT Haplotypes were less and more frequent in controls and patients, respectively (p=3.86×10-7 and p=2.29×10-5. Genotypes distribution among T2D patients with and without DPN compared to healthy controls showed significantly lower frequencies for -318 C/C and +49 A/A genotypes and significantly higher frequencies for -318 C/T and T/T genotypes as well. Our findings indicate that CTLA-4 (+49 A/G and (-318 C/T genotypes could be considered as genetic risk factors associated with susceptibility or protection for T2D.

  20. Mathematical modeling of escape of HIV from cytotoxic T lymphocyte responses (United States)

    Ganusov, Vitaly V.; Neher, Richard A.; Perelson, Alan S.


    Human immunodeficiency virus (HIV-1 or simply HIV) induces a persistent infection, which in the absence of treatment leads to AIDS and death in almost all infected individuals. HIV infection elicits a vigorous immune response starting about 2-3 weeks postinfection that can lower the amount of virus in the body, but which cannot eradicate the virus. How HIV establishes a chronic infection in the face of a strong immune response remains poorly understood. It has been shown that HIV is able to rapidly change its proteins via mutation to evade recognition by virus-specific cytotoxic T lymphocytes (CTLs). Typically, an HIV-infected patient will generate 4-12 CTL responses specific for parts of viral proteins called epitopes. Such CTL responses lead to strong selective pressure to change the viral sequences encoding these epitopes so as to avoid CTL recognition. Indeed, the viral population ‘escapes’ from about half of the CTL responses by mutation in the first year. Here we review experimental data on HIV evolution in response to CTL pressure, mathematical models developed to explain this evolution, and highlight problems associated with the data and previous modeling efforts. We show that estimates of the strength of the epitope-specific CTL response depend on the method used to fit models to experimental data and on the assumptions made regarding how mutants are generated during infection. We illustrate that allowing CTL responses to decay over time may improve the model fit to experimental data and provides higher estimates of the killing efficacy of HIV-specific CTLs. We also propose a novel method for simultaneously estimating the killing efficacy of multiple CTL populations specific for different epitopes of HIV using stochastic simulations. Lastly, we show that current estimates of the efficacy at which HIV-specific CTLs clear virus-infected cells can be improved by more frequent sampling of viral sequences and by combining data on sequence evolution with

  1. Quantifying the impact of human immunodeficiency virus-1 escape from cytotoxic T-lymphocytes.

    Directory of Open Access Journals (Sweden)

    Ulrich D Kadolsky

    Full Text Available HIV-1 escape from the cytotoxic T-lymphocyte (CTL response leads to a weakening of viral control and is likely to be detrimental to the patient. To date, the impact of escape on viral load and CD4(+ T cell count has not been quantified, primarily because of sparse longitudinal data and the difficulty of separating cause and effect in cross-sectional studies. We use two independent methods to quantify the impact of HIV-1 escape from CTLs in chronic infection: mathematical modelling of escape and statistical analysis of a cross-sectional cohort. Mathematical modelling revealed a modest increase in log viral load of 0.051 copies ml(-1 per escape event. Analysis of the cross-sectional cohort revealed a significant positive association between viral load and the number of "escape events", after correcting for length of infection and rate of replication. We estimate that a single CTL escape event leads to a viral load increase of 0.11 log copies ml(-1 (95% confidence interval: 0.040-0.18, consistent with the predictions from the mathematical modelling. Overall, the number of escape events could only account for approximately 6% of the viral load variation in the cohort. Our findings indicate that although the loss of the CTL response for a single epitope results in a highly statistically significant increase in viral load, the biological impact is modest. We suggest that this small increase in viral load is explained by the small growth advantage of the variant relative to the wildtype virus. Escape from CTLs had a measurable, but unexpectedly low, impact on viral load in chronic infection.

  2. Control of mucosal virus infection by influenza nucleoprotein-specific CD8+ cytotoxic T lymphocytes

    Directory of Open Access Journals (Sweden)

    Couch Robert B


    Full Text Available Abstract Background MHC class I-restricted CD8+ cytotoxic T lymphocytes (CTL are thought to play a major role in clearing virus and promoting recovery from influenza infection and disease. This has been demonstrated for clearance of influenza virus from the lungs of infected mice. However, human influenza infection is primarily a respiratory mucosal infection involving the nasopharynx and tracheobronchial tree. The role of CD8+ CTL directed toward the influenza nucleoprotein (NP in defense against influenza virus infection at the respiratory mucosa was evaluated in two separate adoptive transfer experiments. Methods Influenza nucleoprotein (NP-specific CD8+ CTL were generated from splenocytes obtained from Balb/c mice previously primed with influenza A/Taiwan/1/86 (H1N1 infection or with influenza A/PR/8/34 (H1N1-derived NP plasmid DNA vaccine followed by infection with A/Hong Kong/68 (H3N2 virus. After in vitro expansion by exposure to an influenza NP-vaccinia recombinant, highly purified CD8+ T cells exhibited significant lysis in vitro of P815 target cells infected with A/Hong Kong/68 (H3N2 virus while the CD8- fraction (CD4+ T cells, B cells and macrophages had no CTL activity. Purified CD8+ and CD8- T cells (1 × 107 were injected intravenously or interperitoneally into naive mice four hours prior to intranasal challenge with A/HK/68 (H3N2 virus. Results The adoptively transferred NP-vaccinia-induced CD8+ T cells caused significant reduction of virus titers in both the lungs and nasal passages when compared to CD8- cells. Neither CD8+ nor CD8- T cells from cultures stimulated with HIV gp120-vaccinia recombinant reduced virus titers. Conclusion The present data demonstrate that influenza NP-specific CD8+ CTL can play a direct role in clearance of influenza virus from the upper respiratory mucosal surfaces.

  3. Histone deacetylase inhibitors impair the elimination of HIV-infected cells by cytotoxic T-lymphocytes.

    Directory of Open Access Journals (Sweden)

    Richard Brad Jones


    Full Text Available Resting memory CD4+ T-cells harboring latent HIV proviruses represent a critical barrier to viral eradication. Histone deacetylase inhibitors (HDACis, such as suberanilohydroxamic acid (SAHA, romidepsin, and panobinostat have been shown to induce HIV expression in these resting cells. Recently, it has been demonstrated that the low levels of viral gene expression induced by a candidate HDACi may be insufficient to cause the death of infected cells by viral cytopathic effects, necessitating their elimination by immune effectors, such as cytotoxic T-lymphocytes (CTL. Here, we study the impact of three HDACis in clinical development on T-cell effector functions. We report two modes of HDACi-induced functional impairment: i the rapid suppression of cytokine production from viable T-cells induced by all three HDACis ii the selective death of activated T-cells occurring at later time-points following transient exposures to romidepsin or, to a lesser extent, panobinostat. As a net result of these factors, HDACis impaired CTL-mediated IFN-γ production, as well as the elimination of HIV-infected or peptide-pulsed target cells, both in liquid culture and in collagen matrices. Romidepsin exerted greater inhibition of antiviral function than SAHA or panobinostat over the dose ranges tested. These data suggest that treatment with HDACis to mobilize the latent reservoir could have unintended negative impacts on the effector functions of CTL. This could influence the effectiveness of HDACi-based eradication strategies, by impairing elimination of infected cells, and is a critical consideration for trials where therapeutic interruptions are being contemplated, given the importance of CTL in containing rebound viremia.

  4. Candidate mosaic proteins for a pan-filoviral cytotoxic T-Cell lymphocyte vaccine

    Energy Technology Data Exchange (ETDEWEB)

    Fenimore, Paul W [Los Alamos National Laboratory; Fischer, William M [Los Alamos National Laboratory; Kuiken, Carla [Los Alamos National Laboratory; Foley, Brian T [Los Alamos National Laboratory; Thurmond, J R [Los Alamos National Laboratory; Yusim, K [Los Alamos National Laboratory; Korber, B T [Los Alamos National Laboratory


    The extremely high fatality rates of many filovirus (FILV) strains the recurrent but rarely identified origin of human epidemics, the only partly identified viral reservoirs and the continuing non-human primate epizootics in Africa make a broadly-protective filovirus vaccine highly desirable. Cytotoxic T-cells (CTL) have been shown to be protective in mice, guinea pigs and non-human primates. In murine models the cytotoxic T-cell epitopes that are protective against Ebola virus have been mapped and in non-human primates CTL-mediated protection between viral strains (John Dye: specify) has been demonstrated using two filoviral proteins, nucleoprotein (NP) and glycoprotein (GP). These immunological results suggest that the CTL avenue of immunity deserves consideration for a vaccine. The poorly-understood viral reservoirs means that it is difficult to predict what strains are likely to cause epidemics. Thus, there is a premium on developing a pan-filoviral vaccine. The genetic diversity of FILV is large, roughly the same scale as human immunodeficiency virus (HIV). This presents a serious challenge for the vaccine designer because a traditional vaccine aspiring to pan-filoviral coverage is likely to require the inclusion of many antigenic reagents. A recent method for optimizing cytotoxic T-cell lymphocyte epitope coverage with mosaic antigens was successful in improving potential CTL epitope coverage against HIV and may be useful in the context of very different viruses, such as the filoviruses discussed here. Mosaic proteins are recombinants composed of fragments of wild-type proteins joined at locations resulting in exclusively natural k-mers, 9 {le} k {le} 15, and having approximately the same length as the wild-type proteins. The use of mosaic antigens is motivated by three conjectures: (1) optimizing a mosaic protein to maximize coverage of k-mers found in a set of reference proteins will give better odds of including broadly-protective CTL epitopes in a vaccine

  5. Genotoxic evaluation of Halfenprox using the human peripheral lymphocyte micronucleus assay and the Ames test. (United States)

    Akyıl, Dilek; Eren, Yasin; Konuk, Muhsin; Dere, Hatice; Serteser, Ahmet


    The genotoxicity and mutagenicity of Halfenprox, a synthetic pyrethroid insecticide and acaricide, was assessed using two standard genotoxicity assays of the Salmonella typhimurium mutagenicity assay (Ames test) and in vitro micronucleus (MN) assay in human peripheral lymphocytes. In the Ames test, Salmonella strains TA98 and TA100 were treated with or without S9 fraction. The doses of Halfenprox were 6.25, 12.5, 25, 50, and 100 μg/plate and test materials were dissolved in DMSO. The concentrations of Halfenprox did not show mutagenic activity on both strains with and without S9 fraction. The MN assay was used to investigate the genotoxic effects of Halfenprox in human peripheral lymphocytes treated with 250, 500, 750, and 1000 μg/ml concentrations of Halfenprox for 24 and 48 h, and at 1000 μg/ml the concentration was significantly increased and the MN formation was compared with the negative control for both treatment periods. In addition, a significant decrease of the nuclear devision index (NDI) values at the higher concentrations of Halfenprox and at both treatment periods was observed.

  6. The use of the alkaline comet assay with lymphocytes in human biomonitoring studies. (United States)

    Faust, Floriane; Kassie, Fekadu; Knasmüller, Siegfried; Boedecker, Rolf Hasso; Mann, Marion; Mersch-Sundermann, Volker


    We reviewed the data of 45 alkaline comet assay studies with lymphocytes published during the last three years with the objective of monitoring human exposure to genotoxic agents as a result of occupation, drug treatment, diseases or environmental pollution. The strengths of the studies were that: (i) a lot of data could be obtained within a relatively short period of time in a cost-effective manner, (ii) lymphocytes could be easily collected in a non-invasive way and proved to be good surrogate cells in that they picked up effects caused by agents with different cancer target organs and (iii) a remarkable concordance between comet assay and cytogenetic assay data was proved. However, our analysis revealed some shortcomings of the studies such as: (i) the inclusion of low number of study participants and bias in the number and gender of subjects between control and exposed groups, (ii) lack of qualitative and quantitative exposure data, (iii) lack of consideration of differences in physical activity and diet between control and exposed groups, (iv) difficulty in comparison of the studies due to lack of uniformity in the comet assay procedures such as duration of alkali unwinding and electrophoresis, slide scoring method and the metrics used to assess the extent of DNA damage and (v) controversy in the sensitivity of comet assay since it picked up DNA damage caused by agents such as wood dust, pesticides and hormone preparations which were found to be weak genotoxins or non-genotoxins in other tests, but gave inconsistent results with known mutagens/carcinogens such as tobacco smoke. We feel that for the alkaline comet assay to be an important tool in human biomonitoring studies, serious consideration should be given to the flaws in the design and performance of the assay.

  7. Assessment of individual radiosensitivity in human lymphocytes using micronucleus and microgel electrophoresis Comet assays

    Energy Technology Data Exchange (ETDEWEB)

    Giorgio, M. di; Sardi, M.; Busto, M.; Vallerga, M.; Taja, M.; Mairal, I.


    Background and purpose: Individual radiosensitivity is an inherent characteristic, associated with an increased reaction to ionizing radiation on the human body. Individuals show marked differences in radiation sensitivity, which has consequences in the fields of both radiation protection and radiation therapy. It is suggested that DNA repair mechanisms are involved. Consequently, the characterization of DNA repair in lymphocytes through cytokinesis blocked micronucleus (MN) and alkaline single-cell microgel electrophoresis (comet) assays could be suitable approaches to evaluate individual radiosensitivity in vitro. The amins of this study were: 1) to assess the in vitro radisensitivity of peripheral blood lymphocytes from two with the observed clinical response and 2) to test the predictive potential of both techniques. Materials and methods: 38 cancer patients receiving radiation therapy were enrolled in this study. The tumor sites were: head and neck (n=25) and cervic (n=13). 19 pateints were evaluated prior, mid-way and on completion of treatment (prospective group) and 19 patients were evaluated about 2-480 month after radiotherapy (retrospective group). Cytogenetic data from the prospective group were analyzed using a mathematical model to evaluate the attenuation of the cytogenetic effect as a function of the time between a single exposure and blood sampling, estimating a cytogentic recovery factor k. In the retrospective group, blood samples were irradiated in vitro with 0 (control) or 2 Gy and evaluated using MN test. Cytogenetic data were analyzed comparing expected MN frequencies (calibration curve from health donors) with values observed after in vitro irradiation. One over-reactor ad patients that did not develop late effects were also evaluated through comet assay. DNA damage and repair capacity were quantified by the Olive tail moment. Lymphocytes of health individuals were used as reference sample. In the prospective evaluation, factor K correlated

  8. In vitro cytotoxicity assays of solid lipid nanoparticles in epithelial and dermal cells (United States)

    Ridolfi, D. M.; Marcato, P. D.; Machado, D.; Silva, R. A.; Justo, G. Z.; Durán, N.


    In recent years, the interest in nanostructured systems to drug delivery has increased because they offer several advantages over conventional dosage forms. Solid Lipid Nanoparticles (SLN) have been highlighted among these systems because they have advantages such as high physical stability, protection against drug degradation and ease of scale-up and manufacturing, without using organic solvent. The aim of this work was to evaluate the potential of SLN, by in vitro cytotoxicity assays, for dermal drug delivery. SLN of three different lipids were prepared by hot high pressure homogenization and the cytotoxicity was assessed by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test in mouse 3T3 fibroblasts and human HaCaT keratinocytes. SLN showed no cytotoxic potential suggesting a great potential for dermal application.

  9. In vitro cytotoxicity assays of solid lipid nanoparticles in epithelial and dermal cells

    Energy Technology Data Exchange (ETDEWEB)

    Ridolfi, D M; Marcato, P D; Duran, N [Instituto de Quimica, Universidade Estadual de Campinas (Brazil); Machado, D; Silva, R A [Instituto de Biologia, Universidade Estadual de Campinas (Brazil); Justo, G Z, E-mail: [Departamento de BioquImica, Universidade Federal de Sao Paulo (Brazil)


    In recent years, the interest in nanostructured systems to drug delivery has increased because they offer several advantages over conventional dosage forms. Solid Lipid Nanoparticles (SLN) have been highlighted among these systems because they have advantages such as high physical stability, protection against drug degradation and ease of scale-up and manufacturing, without using organic solvent. The aim of this work was to evaluate the potential of SLN, by in vitro cytotoxicity assays, for dermal drug delivery. SLN of three different lipids were prepared by hot high pressure homogenization and the cytotoxicity was assessed by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test in mouse 3T3 fibroblasts and human HaCaT keratinocytes. SLN showed no cytotoxic potential suggesting a great potential for dermal application.

  10. Neutral red uptake assay for the estimation of cell viability/cytotoxicity. (United States)

    Repetto, Guillermo; del Peso, Ana; Zurita, Jorge L


    The neutral red uptake assay provides a quantitative estimation of the number of viable cells in a culture. It is one of the most used cytotoxicity tests with many biomedical and environmental applications. It is based on the ability of viable cells to incorporate and bind the supravital dye neutral red in the lysosomes. Most primary cells and cell lines from diverse origin may be successfully used. Cells are seeded in 96-well tissue culture plates and are treated for the appropriate period. The plates are then incubated for 2 h with a medium containing neutral red. The cells are subsequently washed, the dye is extracted in each well and the absorbance is read using a spectrophotometer. The procedure is cheaper and more sensitive than other cytotoxicity tests (tetrazolium salts, enzyme leakage or protein content). Once the cells have been treated, the assay can be completed in <3 h.

  11. Biocompatibility of various ferrite nanoparticles evaluated by in vitro cytotoxicity assays using HeLa cells

    Energy Technology Data Exchange (ETDEWEB)

    Tomitaka, Asahi [Department of Electrical and Computer Engineering, Yokohama National University, Tokiwadai 79-5, Yokohama, Kanagawa 240-8501 (Japan)], E-mail:; Hirukawa, Atsuo; Yamada, Tsutomu [Department of Electrical and Computer Engineering, Yokohama National University, Tokiwadai 79-5, Yokohama, Kanagawa 240-8501 (Japan); Morishita, Shin [Department of Mechanical Engineering and Materials Science, Yokohama National University, Tokiwadai 79-5, Yokohama, Kanagawa 240-8501 (Japan); Takemura, Yasushi [Department of Electrical and Computer Engineering, Yokohama National University, Tokiwadai 79-5, Yokohama, Kanagawa 240-8501 (Japan)


    Magnetic nanoparticles for thermotherapy must be biocompatible and possess high thermal efficiency as heating elements. The biocompatibility of Fe{sub 3}O{sub 4} (20-30 nm), ZnFe{sub 2}O{sub 4} (15-30 nm) and NiFe{sub 2}O{sub 4} (20-30 nm) nanoparticles was studied using a cytotoxicity colony formation assay and a cell viability assay. The Fe{sub 3}O{sub 4} sample was found to be biocompatible on HeLa cells. While ZnFe{sub 2}O{sub 4} and NiFe{sub 2}O{sub 4} were non-toxic at low concentrations, HeLa cells exhibited cytotoxic effects when exposed to concentrations of 100 {mu}g/ml nanoparticles.

  12. Analysis of HBV-specific cytotoxic T lymphocytes in patients with hepatitis B

    Directory of Open Access Journals (Sweden)

    Ning DING


    Full Text Available Objective To investigate the expression feature of hepatitis B virus(HBV-specific cytotoxic T lymphocytes(CTL,and analyze the role of CTL in immune response.Methods Peripheral venous blood was collected from 40 acute hepatitis B(AHB patients hospitalized from Oct.2008 to Jun.2010 in 302 Hospital of PLA for the detection of human leucocyte antigen-A2(HLA-A2.Out of the 40 patients,18 were HLA-A2-positive,and their peripheral blood mononuclear cells were isolated at acute phase and convalescent phase if the patients could be contacted.Six HLA-A2-negative AHB patients,18 HLA-A2-positive chronic HB patients and 6 HLA-A2-positive normal persons served as controls.The CTL was stained by fluorescence-labeled anti-CD3 monoclonal antibody,anti-CD8 monoclonal antibody and HBV epitopic pentamers(S183-191,S335-343,and examined with flow cytometry,then analyzed by software Cell-quest.The peak value of alanine aminotransferase(ALT and HBV load was detected at acute phase of patients,and the correlation was analyzed.Results The average frequencies were 0.23%±0.18% for HBsAg183-191-specific CTL and 0.49%±0.31% for HBsAg335-343-specific CTL at the acute phase of the 18 AHB patients,and they were significantly higher than those in patients with chronic HB,in whom CTL frequencies were 0.07%±0.03% for HBsAg183-191-specific CTL and 0.08%±0.04% for HBsAg335-343-specific CTL(P < 0.01.There was no correlation between the frequency of HBsAg183-191-specific CTL and the peak value of ALT(r=0.4506,P=0.0528,while the frequency of HBsAg335-343-specific CTL was correlated with ALT level(r=0.5642,P=0.0119.Neither the two CTL frequencies showed correlation with virus load.Compared with the acute phase,the CTL frequencies obviously decreased at convalescent phase(P=0.011.Both kinds of CTL were not detectable in HLA-A2-negative AHB patients and HLA-A2-positive healthy individuals.Conclusion HBV-specific CTL may play an important role in both virus clearance and liver

  13. Assay conditions can influence the outcome of cytotoxicity tests of nanomaterials: better assay characterization is needed to compare studies. (United States)

    Geys, Jorina; Nemery, Benoit; Hoet, Peter H M


    Reliable in vitro studies that generate consistent toxicity data on nanomaterials on a high-throughput scale will be of invaluable significance in the next few years. In this study, we checked the influence of several steps of the experimental design on the outcome: we investigated the role of cell density, viability assay and particle dispersion method, including the influence of serum and effect of a surfactant (Tween 80). The dose-response curve was assessed for ground multiwalled carbon nanotubes (CNT) and the silica benchmark Min-U-Sil, on lung epithelial cells (A549 cells) and macrophages (stimulated THP-1 cells). The cell density used in the cytotoxicity study has an impact on the outcome: for the same concentration of Min-U-Sil, the viability of A549 cells varied from 10% to 55% with increasing cell density. Whereas foetal calf serum attenuated the cytotoxicity of Min-U-Sil, this effect was not seen for CNT. The results show how cell culture conditions can modify the outcome of a toxicological experiment, as shown in this study for Tween 80 to disperse the test agent. These experiments illustrates that results reported in literature can only be compared when, in addition to the use of a benchmark particle, a detailed method description is available. Therefore, more emphasis is needed on a standardized design for cytotoxicity studies. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  14. 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. (United States)

    Takayanagi, Toshiaki


    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.

  15. Most influenza A virus-specific memory cytotoxic T lymphocytes react with antigenic epitopes associated with internal virus determinants



    This paper shows that most murine (C57BL/6) influenza A virus-specific memory cytotoxic T lymphocyte (CTL) clones tested in limiting dilution did not react with the influenza A virus surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). This lysis of syngeneic target cells infected with the influenza A virus strains, Aichi (H3N2), PR8 (H1N1), or recombinant strain X31 (H3N2) indicates that most antigenic epitopes recognized are associated with internal virus determinants. X31 and ...

  16. Dynamic visualization the whole process of cytotoxic T lymphocytes killing the B16 tumor cells in vitro (United States)

    Qi, Shuhong; Zhang, Zhihong


    Cytotoxic T lymphocytes (CTLs) played a key role in the immune system to destroy the tumor cells. Although some mechanisms of CTLs killing the tumor cells are revealed already, the dynamic information of CTLs interaction with tumor cells are still not known very clearly. Here we used confocal microscopy to visualize the whole process of CTLs killing the tumor cells in vitro. The imaging data showed that CTLs destroyed the target tumor cells rapidly and efficiently. Several CTLs surrounded one or some tumor cells and the average time for CTLs destroying one tumor cell is just a few minutes in vitro. The study displayed the temporal events of CTLs interacting with tumor cells at the beginning and finally killing them and directly presented the efficient tumor cell cytotoxicity of the CTLs. The results helped us to deeply understand the mechanism of the CTLs destroying the tumor cells and to develop the cancer immunotherapy.

  17. MHC and non-MHC genes regulate elimination of lymphocytic choriomeningitis virus and antiviral cytotoxic T lymphocyte and delayed-type hypersensitivity mediating T lymphocyte activity in parallel

    DEFF Research Database (Denmark)

    Thomsen, Allan Randrup; Marker, O


    The course of systemic infection with lymphocytic choriomeningitis virus was studied in mouse strains differing in the MHC or non-MHC background. Virus clearance rates differed significantly between H-2 identical strains as well as between congenic strains differing in the H-2L subregion, indicat......The course of systemic infection with lymphocytic choriomeningitis virus was studied in mouse strains differing in the MHC or non-MHC background. Virus clearance rates differed significantly between H-2 identical strains as well as between congenic strains differing in the H-2L subregion...

  18. Tracking in vivo migration and distribution of antigen-specific cytotoxic T lymphocytes by 5,6-carboxyfluorescein diacetate succinimidyl ester staining during cancer immunotherapy

    Institute of Scientific and Technical Information of China (English)

    XU Wei-li; LI Suo-lin; WEN Ming; WEN Jun-ye; HAN Jie; ZHANG Hong-zhen; GAO Fei


    Background Killing of targeted tumors during adoptive cell transfer therapy is associated with cytotoxic T lymphocyte (CTL) numbers,immunophenotype,tumor-specificity,and in vivo residence time,migration,and distribution.Therefore,tracing in vivo persistence,migration,and distribution of CTLs is important for cancer immunotherapy.Methods Optimal staining concentration for CTL proliferation was determined by cell counting kit-8 (CCK-8) assay and killing efficiencies of CTLs or carboxyfluorescein diacetate succinimidyl ester (CFSE)-labeled melanoma antigen-specific cytotoxic T lymphocytes (CFSE-CTLs) for malignant melanoma cells in vitro were compared.Additionally,CFSE-CTLs were intravenously transfused to mice receiving B16 melanoma,and their residence time,migration,and distribution in vivo were observed by measuring fluorescence intensities of CFSE-CTLs per gram of tissue (%FI/g) in various tissues and analyzing tumor/non-tumor (T/NT) values.Anti-tumor effects of transferred CTLs and correlation between %FI/g and D-value of tumor size were analyzed.Results Five-micromolar CFSE was optimal for labeling CTLs with minimal cytotoxicity.No significant difference occurred between CTLs and CFSE-CTLs for tumor cell killing (P=0.849) or interleukin-2 (P=0.318) and interferon-y (P=0.201)levels.Distribution of CTLs in vivo varied with time.A negative correlation between %FI/g in tumors and D-value of tumor sizes by Spearman correlation analysis was observed.CTLs were recruited to and killed tumors from 6 hours to 3 days after cell infusion.CTLs were observed up to three weeks later in the tumor,liver,kidneys,and spleen; this was related to the abundant blood supply or the nature of immune organs.Conclusions CCK-8 assay is a novel method to select optimal CFSE staining concentrations.Fluorescence intensity of transferred CTLs reflects their killing efficiency of tumors.CFSE fluorescent markers can trace in vivo CTL persistence,migration,and distribution because of its

  19. Lymphocyte DNA damage in Turkish asphalt workers detected by the comet assay. (United States)

    Bacaksiz, Aysegul; Kayaalti, Zeliha; Soylemez, Esma; Tutkun, Engin; Soylemezoglu, Tulin


    Asphalt has a highly complex structure and it contains several organic compounds including polycyclic aromatic hydrocarbons and heterocyclic compounds. In this study, comet assay was used to detect the DNA damage in blood lymphocytes of 30 workers exposed to asphalt fumes and 30 nonexposed controls. This is the first report on Turkish asphalt workers' investigated DNA damage using the alkaline single cell gel electrophoresis (SCGE). The DNA damage was evaluated by the percentage of DNA in the comet tail (% tail DNA) for each cell. According to our results, workers exposed to asphalt fumes had higher DNA damage than the control group (p asphalt fumes caused a significant increase in DNA damage and the comet assay is a suitable method for determining DNA damage in asphalt workers.

  20. Evaluation of the DNA damaging effects of amitraz on human lymphocytes in the Comet assay. (United States)

    Radakovic, Milena; Stevanovic, Jevrosima; Djelic, Ninoslav; Lakic, Nada; Knezevic-Vukcevic, Jelena; Vukovic-Gacic, Branka; Stanimirovic, Zoran


    Amitraz is formamidine pesticide widely used as insecticide and acaricide. In veterinary medicine, amitraz has important uses against ticks, mites and lice on animals. Also, amitraz is used in apiculture to control Varroa destructor. It this study, the alkaline Comet assay was used to evaluate DNA damaging effects of amitraz in human lymphocytes. Isolated human lymphocytes were incubated with varying concentrations of amitraz (0.035, 0.35, 3.5, 35 and 350 mu g/mL). The Comet assay demonstrated that all concentrations of amitraz caused statistically significant increase in the level of DNA damage, thus indicating that amitraz possesses genotoxic potential. The concentration of amitraz that produced the highest DNA damage (3.5 mu g/mL) was chosen for further analysis with the antioxidant catalase. The obtained results showed that co-treatment with antioxidant catalase (100 IU/mL or 500 IU/mL) significantly reduced the level of DNA damage, indicating the possible involvement of reactive oxygen species in DNA damaging effects of amitraz. Flow cytometric analysis revealed increase of the apoptotic index following treatment with amitraz. However, co-treatment with catalase reduced the apoptotic index, while treatment with catalase alone reduced the percentage of apoptotoc cells even in comparison with the negative control. Therefore, catalase had protective effects against ROS-mediated DNA damage and apoptosis.

  1. Genotoxicity evaluation of drinking water sources in human peripheral blood lymphocytes using the comet assay

    Institute of Scientific and Technical Information of China (English)

    WU Yulin; CHEN Haigang; LI Zhaoli; SUN Liwei; QU Mengmeng; LI Mei; KONG Zhiming


    The potential harm of organic pollutants in drinking water to human health is widely focused on in the world; more and more pollutants with genotoxic substances are released into the aquatic environment. Water source samples were collected from 7 different localities of Nanjing City. The potential genotoxicity of organic extracts from drinking water sources were investigated by means of the comet assay in human peripheral lymphocytes. The results showed that all the organic extracts from all the water source samples could induce DNA damages of human peripheral blood lymphocytes at different levels. A significant difference (P < 0.01) was observed when compared with the solvent control. The DNA damage increased with the increase of the dosage of the original water source. Significant differences of DNA damage were observed in different drinking water sources, as shown by the multiple comparisons analysis at the dosage of 100×; the degree of DNA damage treated by Hushu waterworks (at town level) was the most serious, the arbitrary units (AU) was 141.62±6.96, however, that of Shangyuanmen waterworks (at city level) was only 109.64±2.97. The analysis also revealed that the genotoxicity of town's water sources was higher than that of the city. The results demonstrated that the comet assay can be successfully applied to the genotoxicity monitoring programs of drinking water sources.

  2. Evaluation of the DNA damaging effects of amitraz on human lymphocytes in the Comet assay

    Indian Academy of Sciences (India)

    Milena Radakovic; Jevrosima Stevanovic; Ninoslav Djelic; Nada Lakic; Jelena Knezevic-Vukcevic; Branka Vukovic-Gacic; Zoran Stanimirovic


    Amitraz is formamidine pesticide widely used as insecticide and acaricide. In veterinary medicine, amitraz has important uses against ticks, mites and lice on animals. Also, amitraz is used in apiculture to control Varroa destructor. It this study, the alkaline Comet assay was used to evaluate DNA damaging effects of amitraz in human lymphocytes. Isolated human lymphocytes were incubated with varying concentrations of amitraz (0.035, 0.35, 3.5, 35 and 350 g/mL). The Comet assay demonstrated that all concentrations of amitraz caused statistically significant increase in the level of DNA damage, thus indicating that amitraz possesses genotoxic potential. The concentration of amitraz that produced the highest DNA damage (3.5 g/mL) was chosen for further analysis with the antioxidant catalase. The obtained results showed that co-treatment with antioxidant catalase (100 IU/mL or 500 IU/mL) significantly reduced the level of DNA damage, indicating the possible involvement of reactive oxygen species in DNA damaging effects of amitraz. Flow cytometric analysis revealed increase of the apoptotic index following treatment with amitraz. However, co-treatment with catalase reduced the apoptotic index, while treatment with catalase alone reduced the percentage of apoptotoc cells even in comparison with the negative control. Therefore, catalase had protective effects against ROS-mediated DNA damage and apoptosis.

  3. Artifacts by marker enzyme adsorption on nanomaterials in cytotoxicity assays with tissue cultures (United States)

    Wohlleben, Wendel; Kolle, Susanne N.; Hasenkamp, Laura-Carolin; Böser, Alexander; Vogel, Sandra; von Vacano, Bernhard; van Ravenzwaay, Ben; Landsiedel, Robert


    We used precision cut lung slices (PCLS) to study the cytotoxicity of cobalt ferrite nanomaterials with and without bovine serum albumin (BSA) stabilization. Using mitochondrial activity as an indicator of cytotoxicity (WST-1 assay) increasing concentrations of cobalt ferrite nanomaterial caused increasing levels of cytotoxicity in PCLS irrespective of BSA stabilization. However, there was no increase in released lactate dehydrogenase (LDH) levels caused by BSA stabilized nanomaterial indicating concentration depended cytotoxictiy. Moreover, non-stabilized nanomaterial caused a decrease of background LDH levels in the PCLS culture supernatant confirmed by complementary methods. Direct characterization of the protein corona of extracted nanomaterial shows that the LDH decrease is due to adsorption of LDH onto the surface of the non-stabilized nanomaterial, correlated with strong agglomeration. Preincubation with serum protein blocks the adsorption of LDH and stabilizes the nanomaterial at low agglomeration. We have thus demonstrated the cytotoxicity of nanomaterials in PCLS does not correlate with disrupted membrane integrity followed by LDH release. Furthermore, we found that intracellular enzymes such as the marker enzyme LDH are able to bind onto surfaces of nanomaterial and thereby adulterate the detection of toxic effects. A replacement of BSA by LDH or a secondary LDH-on-BSA-corona were not observed, confirming earlier indications that the protein corona exchange rate are slow or vanishing on inorganic nanomaterial. Thus, the method(s) to assess nanomaterial-mediated effects have to be carefully chosen based on the cellular effect and possible nano-specific artifacts.

  4. Screening a hybridoma producing a specific monoclonal antibody to HLA-A24+Bw4 antigen by cytotoxicity inhibition assay. (United States)

    Hiroishi, S; Kaneko, T; Arita, J


    A hybridoma secreting a monoclonal antibody (Tsa-1, IgG3) reacting specifically to HLA-A24+Bw4 was screened by cytotoxicity inhibition assay and micrototoxicity test. The R value of the antibody was 0.843.

  5. Screening of endocrine disrupting chemicals with MELN cells, an ER-transactivation assay combined with cytotoxicity assessment. (United States)

    Berckmans, P; Leppens, H; Vangenechten, C; Witters, H


    There is growing concern that some chemicals can cause endocrine disrupting effects to wild animals and humans. Therefore a rapid and reliable screening assay to assess the activity of endocrine disrupting chemicals (EDCs) is required. These EDCs can act at multiple sites. Most studied mechanism is direct interaction with the hormone receptors, e.g. estrogen receptor. In this study the luciferase reporter gene assay using transgenic human MELN cells was used. Since cytotoxicity of the chemicals can decrease the luminescent signal in the transactivation assays, a cytotoxicity assay must be implemented. Mostly the neutral red (NR) assay is performed in parallel with the estrogenicity assay. To increase the reliability and cost-efficiency of the test, a method to measure estrogenicity and cytotoxicity in the same cell culture plate instead of in parallel plates was developed and evaluated. Therefore the NR-assay was compared with the CytoTox-ONE homogeneous membrane integrity assay. The latter measures LDH (lactate dehydrogenase) leakage based on a fluorometric method. For all compounds tested, the CytoTox-ONE test showed comparable curves and EC50-values to those obtained by the NR-assay. So the CytoTox-ONE kit, which seemed more sensitive than measurements of LDH-leakage based on a colorimetric method, is recommended to test cytotoxicity to MELN cells, with the advantage to use the same cells for ER-transactivation measurements. The chemicals tested in the optimised MELN assay showed estrogenic potencies comparable to those reported for several other transactivation assays.

  6. Pattern of CD4 T‑lymphocyte Values in Cancer Patients on Cytotoxic ...

    African Journals Online (AJOL)

    Cytotoxic chemotherapy as well as malignancies is associated with an increased ... drugs induce myelosuppression and that this in effect leads to depletion of both ..... immunodeficiency virus‑negative adolescent and adults in rural northern ...

  7. Genotoxic and antigenotoxic effects of Fucus vesiculosus extract on cultured human lymphocytes using the chromosome aberration and Comet assays

    Directory of Open Access Journals (Sweden)

    Cleide Leite-Silva


    Full Text Available The brown seaweed Fucus vesiculosus (Fucales, Fucaceae was screened for its protective activity using doxorubicin-induced DNA damage in human lymphocytes. In this study, we assessed the genotoxic and antigenotoxic potential of three different concentrations (0.25, 0.5 and 1.0 mg mL-1 of F. vesiculosus aqueous extract using the chromosome aberration and Comet assays. Treatment of human lymphocyte cultures with 0.25, 0.5 and 1.0 mg mL-1 F. vesiculosus aqueous extract had no effect on the chromosome aberration frequency or on the extent of DNA damage detected by the Comet assay. The antigenotoxic effects of the extract were tested in human lymphocyte cultures treated with 15 µg mL-1 of doxorubicin, either alone or combined with the different concentrations of the extract, which was added to the cultures before, simultaneously with or after the doxorubicin. Only when lymphocytes were pre-treated with extract there was a reduction in doxorubicin-induced chromosome aberrations and DNA damage as detected by the Comet assay. These results demonstrate that F. vesiculosus aqueous extract is not genotoxic in cultured human lymphocytes and indicate that when added to lymphocyte cultures before doxorubicin it has antigenotoxic activity against doxorubicin-induced DNA damage.

  8. Assessment of bacterial biodetoxification of herbicide atrazine using Aliivibrio fischeri cytotoxicity assay with prolonged contact time. (United States)

    Háhn, Judit; Szoboszlay, Sándor; Tóth, Gergő; Kriszt, Balázs


    In our study, we determined and compared the atrazine-biodetoxification ability of 41 bacterial strains and 21 consortia created of those with over 50% degradation rate in pure cultures. Biodegradation capacity was measured with GC-MS. Detoxification was assessed based on the cytotoxic effect of end-products to Aliivibrio fischeri in chronic bioluminescence inhibition assay with 25 h contact time. Chronic A. fischeri assay adapted to a microplate, which is suitable for examine numerous residues simultaneously, also appeared to be significantly more sensitive to atrazine compared to the standard acute (30 min) test. Due to its sensitivity, the chronic assay could be a valuable tool to provide a more comprehensive view of the ecological risks of atrazine and other chemicals. Thirteen strains were able to degrade more than 50% of 50 ppm atrazine. Four of these belong to Rhodococcus aetherivorans, R. qingshengii, Serratia fonticola and Olivibacter oleidegradans which species' atrazine degrading ability has never been reported before. Four consortia degrading ability was more effective than that of the creating individual strains; moreover, their residues did not show cytotoxic effects to A. fischeri. However, in several cases, the degradation products of sole strains and consortia resulted in significant bioluminescence inhibition. Thus high biodegradation (>90%) does not certainly mean the reduction or cessation of toxicity highlighting the importance of the evaluation of biological effects of degradation residues to improve the efficiency and abate the ecological risks of bioremediation techniques.

  9. Evaluation of tetrazolium-based semiautomatic colorimetric assay for measurement of human antitumor cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Heo, D.S.; Park, J.G.; Hata, K.; Day, R.; Herberman, R.B.; Whiteside, T.L. (Univ. of Pittsburgh School of Medicine, PA (USA))


    A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based colorimetric assay was developed and compared with 51Cr release from different adherent tumor cell targets (human squamous cell carcinoma lines of the head and neck established in our laboratory, melanoma, and colorectal carcinoma) using 5-7-day human lymphokine-activated killer cells and monocyte-depleted peripheral blood lymphocytes as effectors. With adherent tumor cell targets, MTT colorimetry was more sensitive than the 51Cr release assay in measuring the antitumor activity of effectors: median, 4385 (range, 988-8144) versus median, 1061 (range, 582-7294) lytic units (the number of effector cells required to lyse 20% of 5 x 10(3) targets)/10(7) effectors (P less than 0.01). Background effects (without effector cells) were comparable in 4-h assays (9% versus 10%) between MTT colorimetry and 51Cr release. In 24-h assays, MTT colorimetry showed higher antitumor activity (70-100% versus 40-60% lysis at 1:1 effector:target cell ratio) but lower background effects (6% versus 38%) than 51Cr release assay. Thus, MTT colorimetry was more sensitive, did not use radiolabeled targets, required fewer effector cells, and was easier, less expensive, and better adaptable to serial monitoring of effector cell function in cancer patients. This colorimetric assay is especially well suited to adherent tumor cell targets. The use of adherent tumor cell monolayers, as opposed to trypsinized single cell suspensions, provides an opportunity to measure interactions of effector cells with enzymatically unaltered solid tumor targets. Because of the greater sensitivity of the colorimetric assay, the transformation of MTT data into lytic units, as commonly used for 51Cr release assays, required an adjustment to avoid the extrapolation based on the exponential fit equation.

  10. Murine leukemia RL male 1 and sarcoma Meth A antigens recognized by cytotoxic T lymphocytes (CTL). (United States)

    Uenaka, Akiko; Nakayama, Eiichi


    Peptide elution and expression cloning methods have been used to identify T cell-recognized antigens for which no molecular information is available. We identified a unique tumor antigen peptide pRL1a, IPGLPLSL that is recognized by CTL on BALB/c RL male 1 leukemia by peptide elution. The sequence of the peptide corresponded to the normally untranslated 5' region of akt. Cytotoxicity was generated in BALB/c spleen cells by in vivo and in vitro sensitization with pRL1a peptide in the form of multiple antigen peptide (MAP), but not the original form. pRL1a MAP immunization had a significant growth-inhibitory effect. pRL1a MAP was mostly internalized into the endosomal compartment of antigen-presenting cells, leaked to the cytosol, and degraded, and the pRL1a peptide produced was presented through the MHC class I pathway. In vivo depletion of CD4 T cells from tumor-inoculated BALB/c mice caused RL male 1 regression. Overexpression of the RLakt molecule seemed to induce CD4 immunoregulatory cells, which resulted in progressive RL male 1 growth in BALB/c mice. In vivo administration of anti-CD25 mAb (PC61) caused regression of RL male 1, suggesting that CD4(+) CD25(+) immunoregulatory cells were involved in the tumor growth. Recently, we improved the sensitivity and the efficacy of T cell antigen cloning from cDNA expression libraries by using large- and small-scale ELISPOT assays. Using the IFN-gamma ELISPOT method, we obtained a cDNA clone S35 of 937 bp recognized by AT-1 CTL on BALB/c Meth A sarcoma. S35 was a part of the retinoic acid-regulated nuclear matrix-associated protein (ramp). AT-1 CTL recognized the peptide LGAEAIFRL, which was derived from a newly created open reading frame due to the exon 14 extension.

  11. Genotoxic and Cytotoxic Safety Evaluation of Papain (Carica papaya L. Using In Vitro Assays

    Directory of Open Access Journals (Sweden)

    Claudia R. da Silva


    This work evaluated the toxic and mutagenic potential of papain and its potential antioxidant activity against induced-H2O2 oxidative stress in Escherichia coli strains. Cytotoxicity assay, Growth inhibition test, WP2-Mutoxitest and Plasmid-DNA treatment, and agarose gel electrophoresis were used to investigate if papain would present any toxic or mutagenic potential as well as if papain would display antioxidant properties. Papain exhibited negative results for all tests. This agent presented an activity protecting cells against H2O2-induced mutagenesis.

  12. Response of Lymphocytes to Radiation in Untreated Breast Cancer Patients as Detected with Three Different Genetic Assays

    Institute of Scientific and Technical Information of China (English)



    To detect the response of lymphocytes to radiation in untreated breast cancer patients with three different genetic assays.Methods Blood samples were collected from 25 untreated patients and 25 controls.Each blood sample was divided into two parts:one was irradiated by 3-Gy X-ray (irradiated sample),the other was not irradiated (non-irradiated sample).The radiosensitivity of lymphocytes was assessed by comet assay,cytokinesis-block micronucleus (CBMN) assay and 6-TG-resistant cells scored (TG) assay.Results The baseline values of micronucleated cell frequency (MCF) and micronucleus frequency (MNF) in the patients were significantly higher than those in the controls (P<0.01),and 3-Gy X-ray induced genetic damage to lymphocytes in the patients increased significantly as compared with that in the controls as detected with the three genetic assays (P<0.01).The proportion of radiosensitive cases in the patient group was 48% for the mean tail length (MTL),40% for the mean tail moment (MTM),40% for MCE 44% for MNE and 48% for mutation frequencies of the hprt gene (Mfs-hprt),respectively,whereas the proportion of radiosensitive cases in the control group was only 8% for all the parameters.Conclusion The difference in the lymphocyte radiosensitivity between the breast cancer patients and the controls is significant.Moreover,there are wide individual variations in lymphocyte radiosensitivity of patients with breast cancer.In some cases,the radiosensitivity of the same patient may be different as detected with the different assays.It is suggested that multiple assays should be used to assess the radiosensitivity of patients with breast cancer before therapy.

  13. Editor's Highlight: Analysis of the Effects of Cell Stress and Cytotoxicity on In Vitro Assay Activity Across a Diverse Chemical and Assay Space. (United States)

    Judson, Richard; Houck, Keith; Martin, Matt; Richard, Ann M; Knudsen, Thomas B; Shah, Imran; Little, Stephen; Wambaugh, John; Woodrow Setzer, R; Kothya, Parth; Phuong, Jimmy; Filer, Dayne; Smith, Doris; Reif, David; Rotroff, Daniel; Kleinstreuer, Nicole; Sipes, Nisha; Xia, Menghang; Huang, Ruili; Crofton, Kevin; Thomas, Russell S


    Chemical toxicity can arise from disruption of specific biomolecular functions or through more generalized cell stress and cytotoxicity-mediated processes. Here, responses of 1060 chemicals including pharmaceuticals, natural products, pesticidals, consumer, and industrial chemicals across a battery of 815 in vitro assay endpoints from 7 high-throughput assay technology platforms were analyzed in order to distinguish between these types of activities. Both cell-based and cell-free assays showed a rapid increase in the frequency of responses at concentrations where cell stress/cytotoxicity responses were observed in cell-based assays. Chemicals that were positive on at least 2 viability/cytotoxicity assays within the concentration range tested (typically up to 100 μM) activated a median of 12% of assay endpoints whereas those that were not cytotoxic in this concentration range activated 1.3% of the assays endpoints. The results suggest that activity can be broadly divided into: (1) specific biomolecular interactions against one or more targets (eg, receptors or enzymes) at concentrations below which overt cytotoxicity-associated activity is observed; and (2) activity associated with cell stress or cytotoxicity, which may result from triggering specific cell stress pathways, chemical reactivity, physico-chemical disruption of proteins or membranes, or broad low-affinity non-covalent interactions. Chemicals showing a greater number of specific biomolecular interactions are generally designed to be bioactive (pharmaceuticals or pesticidal active ingredients), whereas intentional food-use chemicals tended to show the fewest specific interactions. The analyses presented here provide context for use of these data in ongoing studies to predict in vivo toxicity from chemicals lacking extensive hazard assessment.

  14. A simple and sensitive flow cytometric assay for determination of the cytotoxic activity of human natural killer cells

    NARCIS (Netherlands)

    Radosevic, Katarina; Radosevic, K.; Garritsen, Henk S.P.; Garritsen, H.S.P.; van Graft, M.; van Graft, Marja; de Grooth, B.G.; Greve, Jan


    A new, simple and sensitive flow cytometric assay for the determination of the cytotoxic activity of human natural killer cells is described. The assay is based on the use of two fluorochromes. The target cell population is stained with one fluorochrome (octadecylamine-fluorescein isothiocyanate,

  15. A Neutralizing Antibody Assay Based on a Reporter of Antibody-Dependent Cell-Mediated Cytotoxicity. (United States)

    Wu, Yuling; Li, Jia J; Kim, Hyun Jun; Liu, Xu; Liu, Weiyi; Akhgar, Ahmad; Bowen, Michael A; Spitz, Susan; Jiang, Xu-Rong; Roskos, Lorin K; White, Wendy I


    Benralizumab is a humanized anti-IL5 receptor α (IL5Rα) monoclonal antibody (mAb) with enhanced (afucosylation) antibody-dependent cell-mediated cytotoxicity (ADCC) function. An ADCC reporter cell-based neutralizing antibody (NAb) assay was developed and characterized to detect NAb against benralizumab in human serum to support the clinical development of benralizumab. The optimal ratio of target cells to effector cells was 3:1. Neither parental benralizumab (fucosylated) nor benralizumab Fab resulted in ADCC activity, confirming the requirement for ADCC activity in the NAb assay. The serum tolerance of the cells was determined to be 2.5%. The cut point derived from normal and asthma serum samples was comparable. The effective range of benralizumab was determined, and 35 ng/mL [80% maximal effective concentration (EC80)] was chosen as the standard concentration to run in the assessment of NAb. An affinity purified goat anti-benralizumab polyclonal idiotype antibody preparation was shown to have NAb since it inhibited ADCC activity in a dose-dependent fashion. The low endogenous concentrations of IL5 and soluble IL5 receptor (sIL5R) did not demonstrate to interfere with the assay. The estimated assay sensitivities at the cut point were 1.02 and 1.10 μg/mL as determined by the surrogate neutralizing goat polyclonal and mouse monoclonal anti-drug antibody (ADA) controls, respectively. The assay can detect NAb (at 2.5 μg/mL) in the presence of 0.78 μg/mL benralizumab. The assay was not susceptible to non-specific matrix effects. This study provides an approach and feasibility of developing an ADCC cell-based NAb assay to support biopharmaceuticals with an ADCC function.

  16. Interactive effects of metals as measured in cytotoxicity assays with established fish cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Segner, H.; Schuurmann, G. [Centre for Environmental Research, Leipzig (Germany). Dept. of Chemical Ecotoxicology


    The environmental toxicity of chemicals is often judged on the basis of toxicity tests with single compounds. One major drawback of this approach is the fact, that mixture effects occurring in aquatic ecosystems with a multitude of different chemicals are not accounted for. The present work explores the use of cytotoxicity assays with established fish cell lines as a rapid and economic approach to derive basic data on joint toxicity effects of heavy metals. For the assessment of mixture toxicity, concentration addition is taken as the reference model of no interaction, and both isobolographic analysis and calculation of mixture toxicity indices are used to analyze the effect profile of various equitoxic compound mixtures. Cytotoxic endpoints used include neutral red uptake inhibition assay as a measure of cell viability, proliferation measurements to estimate toxic effects on cell growth, and analysis of glutathion contents to estimate metabolic stress effects. The single toxicity of the metals silver, mercury, cadmium, copper, zinc, lead and nickel towards the cell lines RI from rainbow trout liver and RTG-2 from rainbow trout gonads was found to depend on the chemical softness parameter of the cations. The joint effect profile will be discussed in terms of the single effects and softness domain of the heavy metals.

  17. Enhancement of lytic activity of leukemic cells by CD8+ cytotoxic T lymphocytes generated against a WT1 peptide analogue. (United States)

    Al Qudaihi, Ghofran; Lehe, Cynthia; Negash, Muna; Al-Alwan, Monther; Ghebeh, Hazem; Mohamed, Said Yousuf; Saleh, Abu-Jafar Mohammed; Al-Humaidan, Hind; Tbakhi, Abdelghani; Dickinson, Anne; Aljurf, Mahmoud; Dermime, Said


    The Wilms tumor antigen 1 (WT1) antigen is over-expressed in human leukemias, making it an attractive target for immunotherapy. Most WT1-specific Cytotoxic T Lymphocytes (CTLs) described so far displayed low avidity, limiting its function. To improve the immunogenicity of CTL epitopes, we replaced the first-amino-acid of two known immunogenic WT1-peptides (126 and 187) with a tyrosine. This modification enhances 126Y analogue-binding ability, triggers significant number of IFN-gamma-producing T cells (P = 0.0003), induces CTL that cross-react with the wild-type peptide, exerts a significant lytic activity against peptide-loaded-targets (P = 0.0006) and HLA-A0201-matched-leukemic cells (P = 0.0014). These data support peptide modification as a feasible approach for the development of a leukemia-vaccine.

  18. Revival of the identification of cytotoxic T-lymphocyte epitopes for immunological diagnosis, therapy and vaccine development. (United States)

    Liu, Jun; Zhang, Shihong; Tan, Shuguang; Zheng, Beiwen; Gao, George F


    Immunogenic T-cell epitopes have a central role in the cellular immunity against pathogens and tumors. However, in the early stage of cellular immunity studies, it was complicated and time-consuming to identify and characterize T-cell epitopes. Currently, the epitope screening is experiencing renewed enthusiasm due to advances in novel techniques and theories. Moreover, the application of T-cell epitope-based diagnoses for tuberculosis and new data on epitope-based vaccine development have also revived the field. There is a growing knowledge on the emphasis of epitope-stimulated T-cell immune responses in the elimination of pathogens and tumors. In this review, we outline the significance of the identification and characterization of T-cell epitopes. We also summarize the methods and strategies for epitope definition and, more importantly, address the relevance of cytotoxic T-lymphocyte epitopes to clinical diagnoses, therapy and vaccine development.

  19. Identification of a nonameric H-2Kk-restricted CD8+ cytotoxic T lymphocyte epitope on the Plasmodium falciparum circumsporozoite protein

    DEFF Research Database (Denmark)

    Malik, A; Houghten, R; Corradin, G


    Class I-restricted CD8+ cytotoxic T lymphocytes (CTL) against the circumsporozoite protein (CSP) protect mice against the rodent malaria parasite, Plasmodium yoelii, and vaccines designed to produce protective CTL against the P. falciparum CSP (PfCSP) are under development. Humans and B10.BR (H-2k...

  20. The loss of immunodominant epitopes affects interferon-γ production and lytic activity of the human influenza virus-specific cytotoxic T lymphocyte response in vitro

    NARCIS (Netherlands)

    E.G.M. Berkhoff (Eufemia); M.M. Geelhoed-Mieras (Martina); E.J. Verschuren (Esther); C.A. van Baalen (Carel); R.A. Gruters (Rob); R.A.M. Fouchier (Ron); A.D.M.E. Osterhaus (Albert); G.F. Rimmelzwaan (Guus)


    textabstractIn the present study, we examined the effect of the loss of the human leucocyte antigen (HLA)-B*3501-restricted nucleoprotein (NP)418-426epitope on interferon (IFN)-γ-production and lytic activity of the human cytotoxic T lymphocyte (CTL) response in vitro. Extensive amino acid variation

  1. Spontaneous human squamous cell carcinomas are killed by a human cytotoxic T lymphocyte clone recognizing a wild-type p53-derived peptide

    DEFF Research Database (Denmark)

    Röpke, M; Hald, J; Guldberg, Per


    A cytotoxic T lymphocyte (CTL) clone generated in vitro from the peripheral blood of a healthy HLA-A2-positive individual against a synthetic p53 protein-derived wild-type peptide (L9V) was shown to kill squamous carcinoma cell lines derived from two head and neck carcinomas, which expressed mutant...

  2. The presence of protective cytotoxic T lymphocytes does not correlate with shorter lifespans of productively infected cells in HIV-1 infection

    NARCIS (Netherlands)

    Spits, Hilde B; Mudrikova, Tania; Schellens, Ingrid M M; Wensing, Annemarie M J; Prins, Jan M; Feuth, Thijs; Spierings, Erik; Nijhuis, Monique; van Baarle, Debbie; Borghans, José A M


    OBJECTIVES AND DESIGN: CD8+ cytotoxic T lymphocytes (CTL) are important in the control of HIV infection. Although CTL are thought to reduce the lifespan of productively infected cells, CD8+ T-cell depletion in simian immunodeficiency virus-infected rhesus-macaques showed no effect on the lifespan of

  3. Human infection with Trypanosoma cruzi induces parasite antigen-specific cytotoxic T lymphocyte responses.



    Experimental models of Chagas' disease, an infection caused by the intracellular protozoan Trypanosoma cruzi, have demonstrated the crucial immunoprotective role played by CD8(+) T lymphocytes. These cells dominate inflammatory foci in parasitized tissues and their elimination from mice leads to uncontrolled parasite replication and subsequent death of the infected host. A trypomastigote surface antigen, TSA-1, and two amastigote surface molecules, ASP-1 and ASP-2, were recently identified as...

  4. Cytotoxic T lymphocytes promote cytarabine-induced acute myeloid leukemia cell apoptosis via inhibiting Bcl-2 expression. (United States)

    Deng, Rui; Fan, Fang-Yi; Yi, Hai; Fu, Li; Zeng, Yan; Wang, Yi; Miao, Xiao-Juan; Shuai, Yan-Rong; He, Guang-Cui; Su, Yi


    Acute myeloid leukemia (AML) remains difficult to cure due to its drug tolerance and refractoriness. Immunotherapy is a growing area of cancer research, which has been applied for the treatment of numerous types of cancer, including leukemia. The present study generated AML cell-specific cytotoxic T lymphocytes (CTLs) in vitro and investigated the effect of combining CTL treatment with one of the most commonly used drugs for the treatment of hematological malignancies, cytarabine, on AML cell apoptosis. Firstly, it was observed that monocyte-depleted peripheral blood lymphocytes from healthy donors could be used to generate large numbers of CD3(+)CD8(+) CTLs through immune stimulation. These CD3(+)CD8(+) CTLs could effectively recognize and induce the apoptosis of human Kasumi-3 AML cells. In addition, cytarabine-induced AML cell apoptosis was enhanced by CTL treatment. Western blotting revealed that Bcl-2 expression was downregulated in AML cells following cytarabine and CTL treatment, indicating that the synergistic effect of this treatment on AML cell apoptosis is due to the downregulation of Bcl-2. These results highlight the potential application of CTL immunotherapy for the treatment of AML. Further studies optimizing the specificity and potency of CTLs, and identifying favorable combinations with other chemotherapeutic drug are required.

  5. HLA-A2–Restricted Cytotoxic T Lymphocyte Epitopes from Human Heparanase as Novel Targets for Broad-Spectrum Tumor Immunotherapy

    Directory of Open Access Journals (Sweden)

    Ting Chen


    Full Text Available Peptide vaccination for cancer immunotherapy requires identification of peptide epitopes derived from antigenic proteins associated with tumors. Heparanase (Hpa is broadly expressed in various advanced tumors and seems to be an attractive new tumor-associated antigen. The present study was designed to predict and identify HLA-A2– restricted cytotoxic T lymphocyte (CTL epitopes in the protein of human Hpa. For this purpose, HLA-A2–restricted CTL epitopes were identified using the following four-step procedure: 1 a computer-based epitope prediction from the amino acid sequence of human Hpa, 2 a peptide-binding assay to determine the affinity of the predicted protein with the HLA-A2 molecule, 3 stimulation of the primary T-cell response against the predicted peptides in vitro, and 4 testing of the induced CTLs toward different kinds of carcinoma cells expressing Hpa antigens and/or HLA-A2. The results demonstrated that, of the tested peptides, effectors induced by peptides of human Hpa containing residues 525-533 (PAFSYSFFV, Hpa525, 277-285 (KMLKSFLKA, Hpa277, and 405-413 (WLSLLFKKL, Hpa405 could effectively lyse various tumor cell lines that were Hpa-positive and HLA-A2-matched. We also found that these peptide-specific CTLs could not lyse autologous lymphocytes with low Hpa activity. Further study revealed that Hpa525, Hpa277, and Hpa405 peptides increased the frequency of IFN-γ–producing T cells compared to a negative peptide. Our results suggest that Hpa525, Hpa277, and Hpa405 peptides are new HLA-A2–restricted CTL epitopes capable of inducing Hpa-specific CTLs in vitro. Because Hpa is expressed in most advanced malignant tumors, Hpa525, Hpa277, and Hpa405 peptide–based vaccines may be useful for the immunotherapy for patients with advanced tumors.

  6. Improved cytotoxic T-lymphocyte immune responses to a tumor antigen by vaccines co-expressing the SLAM-associated adaptor EAT-2. (United States)

    Aldhamen, Y A; Seregin, S S; Kousa, Y A; Rastall, D P W; Appledorn, D M; Godbehere, S; Schutte, B C; Amalfitano, A


    The signaling lymphocytic activation molecule-associated adaptor Ewing's sarcoma's-activated transcript 2 (EAT-2) is primarily expressed in dendritic cells, macrophages and natural killer cells. Including EAT-2 in a vaccination regimen enhanced innate and adaptive immune responses toward pathogen-derived antigens, even in the face of pre-existing vaccine immunity. Herein, we investigate whether co-vaccinations with two recombinant Ad5 (rAd5) vectors, one expressing the carcinoembryonic antigen (CEA) and one expressing EAT-2, can induce more potent CEA-specific cytotoxic T lymphocyte (CTL) and antitumor activity in the therapeutic CEA-expressing MC-38 tumor model. Our results suggest that inclusion of EAT-2 significantly alters the kinetics of Th1-biasing proinflammatory cytokine and chemokine responses, and enhances anti-CEA-specific CTL responses. As a result, rAd5-EAT2-augmented rAd5-CEA vaccinations are more efficient in eliminating CEA-expressing target cells as measured by an in vivo CTL assay. Administration of rAd5-EAT2 vaccines also reduced the rate of growth of MC-38 tumor growth in vivo. Also, an increase in MC-38 tumor cell apoptosis (as measured by hematoxylin and eosin staining, active caspase-3 and granzyme B levels within the tumors) was observed. These data provide evidence that more efficient, CEA-specific effector T cells are generated by rAd5 vaccines expressing CEA, when augmented by rAd5 vaccines expressing EAT-2, and this regimen may be a promising approach for cancer immunotherapy in general.

  7. Antigen-specific cytotoxic T lymphocytes target airway CD103+ and CD11b+ dendritic cells to suppress allergic inflammation. (United States)

    Daniels, N J; Hyde, E; Ghosh, S; Seo, K; Price, K M; Hoshino, K; Kaisho, T; Okada, T; Ronchese, F


    Allergic airway inflammation is driven by the recognition of inhaled allergen by T helper type 2 (Th2) cells in the airway and lung. Allergen-specific cytotoxic T lymphocytes (CTLs) can strongly reduce airway inflammation, however, the mechanism of their inhibitory activity is not fully defined. We used mouse models to show that allergen-specific CTLs reduced early cytokine production by Th2 cells in lung, and their subsequent accumulation and production of interleukin (IL)-4 and IL-13. In addition, treatment with specific CTLs also increased the proportion of caspase(+) dendritic cells (DCs) in mediastinal lymph node (MLN), and decreased the numbers of CD103(+) and CD11b(+) DCs in the lung. This decrease required expression of the cytotoxic mediator perforin in CTLs and of the appropriate MHC-antigen ligand on DCs, suggesting that direct CTL-DC contact was necessary. Lastly, lung imaging experiments revealed that in airway-challenged mice XCR1-GFP(+) DCs, corresponding to the CD103(+) DC subset, and XCR1-GFP(-) CD11c(+) cells, which include CD11b(+) DCs and alveolar macrophages, both clustered in the areas surrounding the small airways and were closely associated with allergen-specific CTLs. Thus, allergen-specific CTLs reduce allergic airway inflammation by depleting CD103(+) and CD11b(+) DC populations in the lung, and may constitute a mechanism through which allergic immune responses are regulated.

  8. Prediction and identification of HLA-A*0201-restricted epitopes from leukemia-associated protein MLAA-22 which elicit cytotoxic T lymphocytes. (United States)

    Li, Jing; Bai, Ju; Gu, Liufang; He, Aili; Wang, Jin; Wang, Jianli; Zhang, Pengyu; Zhang, Wanggang


    Cytotoxic T lymphocytes (CTLs) play a critical role in the control of leukemia. However, few effective CTL epitopes have been identified to date yet. We previously reported that MLAA-22, a protein composed of 631 amino acid residues, is a novel acute myeloid leukemia (AML)-associated antigen. In the present study, ten high-score 9-mer peptides, which were selected from MLAA-22 by using ProPred1 and SYFPEITHI bioinformatics tools, were screened to identify HLA-A*0201-restricted-specific CTL epitopes. Monocyte-derived dendritic cells were generated in vitro to be used as antigen-presenting cells for the induction of CTLs. We found that peptide MLAA-22(379-387) (LLPNAIYKV) exhibited the highest binding affinity to HLA-A*0201 among all peptide candidates in the peptide-T2 binding assay. The percentage of positive T2 cells treated with MLAA-22(379-387) was about 96.3%, which is even higher than that of the positive control peptide CML28(173-181) (95.1%). MLAA-22(379-387)-induced CTLs showed the most significant cytotoxic activity and apparent killing effects on the cell lines including THP-1 (human acute monocytic leukemia), A549, T2, U937, and MCF-7, and the specific lysis ratios were 83.8, 32.6, 64.4, 64.4, and 32.6%, respectively, when the effector to target ratio (E/T) was 20:1. Specific lysis (%) of MLAA1 was significantly increased (P AML immunotherapy.

  9. Endocytosis of Cytotoxic Granules Is Essential for Multiple Killing of Target Cells by T Lymphocytes. (United States)

    Chang, Hsin-Fang; Bzeih, Hawraa; Schirra, Claudia; Chitirala, Praneeth; Halimani, Mahantappa; Cordat, Emmanuelle; Krause, Elmar; Rettig, Jens; Pattu, Varsha


    CTLs are serial killers that kill multiple target cells via exocytosis of cytotoxic granules (CGs). CG exocytosis is tightly regulated and has been investigated in great detail; however, whether CG proteins are endocytosed following exocytosis and contribute to serial killing remains unknown. By using primary CTLs derived from a knock-in mouse of the CG membrane protein Synaptobrevin2, we show that CGs are endocytosed in a clathrin- and dynamin-dependent manner. Following acidification, endocytosed CGs are recycled through early and late, but not recycling endosomes. CGs are refilled with granzyme B at the late endosome stage and polarize to subsequent synapses formed between the CTL and new target cells. Importantly, inhibiting CG endocytosis in CTLs results in a significant reduction of their cytotoxic activity. Thus, our data demonstrate that continuous endocytosis of CG membrane proteins is a prerequisite for efficient serial killing of CTLs and identify key events in this process.

  10. Use of "one-pot, mix-and-read" peptide-MHC class I tetramers and predictive algorithms to improve detection of cytotoxic T lymphocyte responses in cattle

    DEFF Research Database (Denmark)

    Svitek, Nicholas; Hansen, Andreas Martin; Steinaa, Lucilla


    Peptide-major histocompatibility complex (p-MHC) class I tetramer complexes have facilitated the early detection and functional characterisation of epitope specific CD8(+) cytotoxic T lymphocytes (CTL). Here, we report on the generation of seven recombinant bovine leukocyte antigens (BoLA....... parva CTL epitopes. Using an ELISA assay to measure peptide-BoLA monomer formation and p-MHC class I tetramers of new specificity, we demonstrate that a predicted alternative epitope Tp2(29-37) rather than the previously reported Tp2(27-37) epitope is the correct Tp2 epitope presented by BoLA-6......*04101. We also verified the prediction by NetMHCpan that the Tp5(87-95) epitope reported as BoLA-T5 restricted can also be presented by BoLA-1*02301, a molecule similar in sequence to BoLA-T5. In addition, Tp5(87-95) specific bovine CTL were simultaneously stained by Tp5-BoLA-1*02301 and Tp5-BoLA-T5...

  11. Enhancement of cytotoxic T lymphocyte activity by dendritic cells loaded with Tat-protein transduction domain-fused hepatitis B virus core antigen

    Institute of Scientific and Technical Information of China (English)


    The protein transduction domain (PTD) of human immuno-deficiency virus-1-Tat protein has a unique potency to pen-etrate the cellular membranes. To synthesize the sequence of Tat-PTD and hepatitis B virus core antigen (HBcAg), we spliced these sequences and linked a fusion gene into the pMAL-c2x vector. The fusion proteins were purified by affin-ity chromatography and pulsed with bone marrow -derived den-dritic cells (DCs), and the transduction of recombinant pro-tein was detected by immunofluorescence antibody assay.Results showed that recombinant PTD-HBcAg could pen-etrate into DC cytoplasm while recombinant HBcAg was de-tected on the surface of cells. The percentage of DC surface molecules, such as CD80, CD86 and major histocompatibii-ity complex Ⅱ, and production of cytokine (IL-12pT0) induced by recombinant PTD-HBcAg were significantly higher than those induced by recombinant HBcAg or tumor necrosis fac-tor-α. DCs treated with PTD-HBcAg induced T cells to dif-ferentiate into specific cytotoxic T lymphocytes (CTLs) and enhanced the CTL killing response. In conclusion, the ex-pressed and purified PTD-HBcAg fusion protein could pen-etrate into cells through the plasma membrane, promote DC maturation, and enhance T cells response to generate HBcAg-specific CTLs efficiently.

  12. Association of cytotoxic T-lymphocyte antigen 4 genetic polymorphism, hepatitis C viral infection and B-cell non-Hodgkin lymphoma: an Egyptian study. (United States)

    Khorshied, Mervat Mamdooh; Gouda, Heba Mahmoud; Khorshid, Ola M Reda


    Abstract Genetic and environmental factors are involved in the pathogenesis of non-Hodgkin lymphoma (NHL). The present study aimed to investigate the association between cytotoxic T-lymphocyte antigen 4 (CTLA-4) genetic polymorphism, hepatitis C virus (HCV) infection and B-cell NHL risk in Egypt. Genotyping of CTLA-4 single nucleotide polymorphisms (SNPs) was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay for 181 adult patients with B-NHL and 200 controls. Our study revealed that CTLA-4 + 49 A/G polymorphism conferred increased risk of B-NHL (odds ratio [OR] = 1.7, 95% confidence interval [CI] = 1.36-2.565). The prevalence of HCV infection in individuals harboring the mutant genotype + 49 A/G and - 318 C/T SNPs was higher in patients with B-NHL and was associated with increased risk of B-NHL (OR = 2.79, 95% CI = 1.24-6.93 for + 49 A/G and OR = 3.9, 95% CI = 1.01-15.98 for - 318 C/T). In conclusion, some SNPs of CTLA-4 are genetic risk factors for B-NHL. Moreover, this study identified an association of CTLA-4 + 49 A/G and - 318 C/T promoter polymorphisms with HCV infection.

  13. A new theory of cytotoxic T-lymphocyte memory: implications for HIV treatment

    DEFF Research Database (Denmark)

    Wodarz, D; Page, K M; Arnaout, R A


    reinfection is only effective in a restricted set of circumstances, we find that resolution of the primary infection requires persistence of CTL precursors (GTLp), as well as a fast rate of activation of the CTLp. Since these are commonly the defining characteristics of CTL memory, we propose that CTL memory...... may have evolved in order to clear the virus during primary challenge. We show experimental data from lymphocytic choriomeningitis virus infection in mice, supporting our theory on CTL memory. We adapt our models to HIV and find that immune impairment during the primary phase of the infection may...

  14. Interdependence of initial cell density, drug concentration and exposure time revealed by real-time impedance spectroscopic cytotoxicity assay

    DEFF Research Database (Denmark)

    Caviglia, Claudia; Zor, Kinga; Canepa, Silvia


    We investigated the combined effect of the initial cell density (12 500, 35 000, 75 000, and 100 000 cells cm−2) and concentration of the anti-cancer drug doxorubicin on HeLa cells by performing timedependent cytotoxicity assays using real-time electrochemical impedance spectroscopy. A correlation...... between the rate of cell death and the initial cell seeding density was found at 2.5 μM doxorubicin concentration, whereas this was not observed at 5 or 100 μM. By sensing the changes in the cell–substrate interaction using impedance spectroscopy under static conditions, the onset of cytotoxicity...... was observed 5 h earlier than when using a standard colorimetric end-point assay (MTS) which measures changes in the mitochondrial metabolism. Furthermore, with the MTS assay no cytotoxicity was observed after 15 h of incubation with 2.5 μM doxorubicin, whereas the impedance showed at this time point cell...

  15. Dendritic cells engineered to secrete anti-DcR3 antibody augment cytotoxic T lymphocyte response against pancreatic cancer in vitro (United States)

    Chen, Jiang; Guo, Xiao-Zhong; Li, Hong-Yu; Zhao, Jia-Jun; Xu, Wen-Da


    AIM To investigate the enhanced cytotoxic T lymphocyte responses against pancreatic cancer (PC) in vitro induced by dendritic cells (DCs) engineered to secrete anti-DcR3 monoclonal antibody (mAb). METHODS DCs, T lymphocytes and primary PC cells were obtained from PC patients. DCs were transfected with a designed humanized anti-DcR3 monoclonal antibody heavy and light chain mRNA and/or total tumor RNA (DC-tumor-anti-DcR3 RNA or DC-total tumor RNA) by using electroporation technology. The identification, concentration and function of anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA were determined by western blotting and enzyme-linked immunosorbent assay. After co-culturing of autologous isolated PC cells with target DCs, the effects of secreting anti-DcR3 mAb on RNA-DCs’ viability and apoptosis were assessed by MTT assay and flow cytometry. Analysis of enhanced antigen-specific immune response against PC induced by anti-DcR3 mAb secreting DCs was performed using a 51Cr releasing test. T cell responses induced by RNA-loaded DCs were analyzed by measuring cytokine levels, including IFN-γ, IL-10, IL4, TNF-α and IL-12. RESULTS The anti-DcR3 mAb secreted by DCs reacted with recombinant human DcR3 protein and generated a band with 35 kDa molecular weight. The secreting mAb was transient, peaking at 24 h and becoming undetectable after 72 h. After co-incubation with DC-tumor-anti-DcR3 RNA for designated times, the DcR3 level in the supernatant of autologous PC cells was significantly down-regulated (P < 0.05). DCs secreting anti-DcR3 mAb could improve cell viability and slow down the apoptosis of RNA-loaded DCs, compared with DC-total tumor RNA (P < 0.01). The anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA could enhance the induction of cytotoxic T lymphocytes (CTLs) activity toward RNA-transfected DCs, primary tumor cells, and PC cell lines, compared with CTLs stimulated by DC-total tumor RNA or control group (P < 0.05). Meanwhile, the antigen-specific CTL responses

  16. Utility of lyophilized PMA and ionomycin to stimulate lymphocytes in whole blood for immunological assays. (United States)

    Belouski, Shelley Sims; Wilkinson, Julie; Thomas, John; Kelley, Keith; Wang, Shen-Wu; Suggs, Sid; Ferbas, John


    The need to implement robust biomarkers in clinical trials has never been greater, and such efforts can be easily compromised by reagent instability or simple human error during assay set-up. Many biotechnology and pharmaceutical companies are introducing efforts to conduct biomarker studies under more rigorous settings, and the use of plates or tubes pre-loaded with stimulation or staining reagents could be of value for studies that involve flow cytometry. Five reagents lyophilized from ethanol or CHAPS buffer stock solution of phorbol 12-myristate 13-acetate (PMA) and ionomycin were benchmarked against standard DMSO liquid formulation for their stimulation equivalency. The median fluorescence intensity of phosphorylated ribosomal protein S6 in lymphocytes was assessed on a BD FACSCalibur. We demonstrate here that tubes pre-loaded with lyophilized versions of the liquid reagents can provide equivalent stimulation in healthy volunteer specimens. The value of this approach is that it safeguards against omission or erroneous addition of bulk liquid formulations of PMA and ionomycin to the reaction vessel (i.e., plate or tube) and also lends itself to extended stability/shelf-life of these reagents. On the basis of this initial success, we plan to expand our evaluation of lyophilized reagents so that they can be incorporated into our clinical biomarker campaigns as appropriate.

  17. Generation of cytotoxic T lymphocytes specific for B-cell acute lymphoblastic leukemia family-shared peptides derived from immunoglobulin heavy chain framework region

    Institute of Scientific and Technical Information of China (English)

    LIU Ying; ZHU Ping; HU Ya-mei


    Background Immunoglobulin heavy chain variable region (IgHV) is a well-characterized tumor antigen for B-cell malignancies. It can function as a target for T cell-mediated immune response. Clinical trials of IgHV protein vaccines against lymphoma have demonstrated induction of tumor-specific cytotoxic T lymphocyte (CTL) responses. However,complementary determining regions-based individual vaccines have disadvantages for wide clinical application. Although a recent study demonstrated that immunogenic peptides are derived from framework regions (FR) shared among patients with B-cell lymphoma, how to choose the appropriate peptides for each patient is still unsolved. The aim of this study was to investigate whether immunoglobulin heavy chain FR-derived peptides shared in each IgHV family are potential CTL epitopes presented by B-cell acute lymphoblastic leukemia (B-ALL). Such CTL epitopes might be beneficial to shifting vaccination strategies against B-ALL from individual specificity to family specificity.Methods Seven IgHV gene families were amplified respectively by PCR and sequenced directly from 71 childhood B-ALL cases. Bioinformatics was applied in analyzing characteristics of sequences available and predicting HLA-A*0201-restricted CTL epitopes for each IgHV family. An antigen-specific T cell expansion system was used to generate peptide-specific CTLs. The cytotoxicity of CTLs against B-ALL cells was assessed in the lactate dehydrogenase release assay.Results Complete IgHV rearrangements were identified in all of the 71 B-ALL cases. All of 40 sequences available showed ≥98% homology with the nearest germline IgHV genes, indicating IgHV genes in B-ALL of germline nature.Twelve nonapeptides of high HLA-A*0201-binding scores were obtained from 26 productive IgHV protein sequences. Ten (83%) of the peptides were located in FR1 and FR3 shared among the corresponding IgHV family. CTLs specific for the peptide QLVQSGAEV located in FR1 (3-11) shared among the IgHV1

  18. Cytotoxic T lymphocyte-dependent tumor growth inhibition by a vascular endothelial growth factor-superantigen conjugate

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Qingwen [Shanghai Chest Hospital, Shanghai 200433 (China); State Key Laboratory of Genetic Engineering, Fudan University, Shanghai 200433 (China); Jiang, Songmin [State Key Laboratory of Genetic Engineering, Fudan University, Shanghai 200433 (China); Han, Baohui [Shanghai Chest Hospital, Shanghai 200433 (China); Sun, Tongwen [Wuhan Junyu Innovation Pharmaceuticals, Inc., Wuhan 430079 (China); Li, Zhengnan; Zhao, Lina; Gao, Qiang [College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457 (China); Sun, Jialin, E-mail: [Wuhan Junyu Innovation Pharmaceuticals, Inc., Wuhan 430079 (China)


    Highlights: Black-Right-Pointing-Pointer We construct and purify a fusion protein VEGF-SEA. Black-Right-Pointing-Pointer VEGF-SEA strongly repressed the growth of murine solid sarcoma 180 (S180) tumors. Black-Right-Pointing-Pointer T cells driven by VEGF-SEA were accumulated around tumor cells bearing VEGFR by mice image model. Black-Right-Pointing-Pointer VEGF-SEA can serve as a tumor targeting agent and sequester CTLs into the tumor site. Black-Right-Pointing-Pointer The induced CTLs could release the cytokines, perforins and granzyme B to kill the tumor cells. -- Abstract: T cells are major lymphocytes in the blood and passengers across the tumor vasculature. If these T cells are retained in the tumor site, a therapeutic potential will be gained by turning them into tumor-reactive cytotoxic T lymphocytes (CTLs). A fusion protein composed of human vascular endothelial growth factor (VEGF) and staphylococcal enterotoxin A (SEA) with a D227A mutation strongly repressed the growth of murine solid sarcoma 180 (S180) tumors (control versus VEGF-SEA treated with 15 {mu}g, mean tumor weight: 1.128 g versus 0.252 g, difference = 0.876 g). CD4{sup +} and CD8{sup +} T cells driven by VEGF-SEA were accumulated around VEGFR expressing tumor cells and the induced CTLs could release the tumoricidal cytokines, such as interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). Meanwhile, intratumoral CTLs secreted cytolytic pore-forming perforin and granzyme B proteins around tumor cells, leading to the death of tumor cells. The labeled fusion proteins were gradually targeted to the tumor site in an imaging mice model. These results show that VEGF-SEA can serve as a tumor targeting agent and sequester active infiltrating CTLs into the tumor site to kill tumor cells, and could therefore be a potential therapeutical drug for a variety of cancers.

  19. Low dose decitabine treatment induces CD80 expression in cancer cells and stimulates tumor specific cytotoxic T lymphocyte responses. (United States)

    Wang, Li-Xin; Mei, Zhen-Yang; Zhou, Ji-Hao; Yao, Yu-Shi; Li, Yong-Hui; Xu, Yi-Han; Li, Jing-Xin; Gao, Xiao-Ning; Zhou, Min-Hang; Jiang, Meng-Meng; Gao, Li; Ding, Yi; Lu, Xue-Chun; Shi, Jin-Long; Luo, Xu-Feng; Wang, Jia; Wang, Li-Li; Qu, Chunfeng; Bai, Xue-Feng; Yu, Li


    Lack of immunogenicity of cancer cells has been considered a major reason for their failure in induction of a tumor specific T cell response. In this paper, we present evidence that decitabine (DAC), a DNA methylation inhibitor that is currently used for the treatment of myelodysplastic syndrome (MDS), acute myeloid leukemia (AML) and other malignant neoplasms, is capable of eliciting an anti-tumor cytotoxic T lymphocyte (CTL) response in mouse EL4 tumor model. C57BL/6 mice with established EL4 tumors were treated with DAC (1.0 mg/kg body weight) once daily for 5 days. We found that DAC treatment resulted in infiltration of IFN-γ producing T lymphocytes into tumors and caused tumor rejection. Depletion of CD8(+), but not CD4(+) T cells resumed tumor growth. DAC-induced CTL response appeared to be elicited by the induction of CD80 expression on tumor cells. Epigenetic evidence suggests that DAC induces CD80 expression in EL4 cells via demethylation of CpG dinucleotide sites in the promoter of CD80 gene. In addition, we also showed that a transient, low-dose DAC treatment can induce CD80 gene expression in a variety of human cancer cells. This study provides the first evidence that epigenetic modulation can induce the expression of a major T cell co-stimulatory molecule on cancer cells, which can overcome immune tolerance, and induce an efficient anti-tumor CTL response. The results have important implications in designing DAC-based cancer immunotherapy.

  20. Novel plant virus-based vaccine induces protective cytotoxic T-lymphocyte-mediated antiviral immunity through dendritic cell maturation. (United States)

    Lacasse, Patrick; Denis, Jérôme; Lapointe, Réjean; Leclerc, Denis; Lamarre, Alain


    Currently used vaccines protect mainly through the production of neutralizing antibodies. However, antibodies confer little or no protection for a majority of chronic viral infections that require active involvement of cytotoxic T lymphocytes (CTLs). Virus-like particles (VLPs) have been shown to be efficient inducers of cell-mediated immune responses, but administration of an adjuvant is generally required. We recently reported the generation of a novel VLP system exploiting the self-assembly property of the papaya mosaic virus (PapMV) coat protein. We show here that uptake of PapMV-like particles by murine splenic dendritic cells (DCs) in vivo leads to their maturation, suggesting that they possess intrinsic adjuvant-like properties. DCs pulsed with PapMV-like particles displaying the lymphocytic choriomeningitis virus (LCMV) p33 immunodominant CTL epitope (PapMV-p33) efficiently process and cross-present the viral epitope to p33-specific transgenic T cells. Importantly, the CTL epitope is also properly processed and presented in vivo, since immunization of p33-specific T-cell receptor transgenic mice with PapMV-p33 induces the activation of large numbers of specific CTLs. C57BL/6 mice immunized with PapMV-p33 VLPs in the absence of adjuvant develop p33-specific effector CTLs that rapidly expand following LCMV challenge and protect vaccinated mice against LCMV infection in a dose-dependent manner. These results demonstrate the efficiency of this novel plant virus-based vaccination platform in inducing DC maturation leading to protective CTL responses.

  1. Low dose decitabine treatment induces CD80 expression in cancer cells and stimulates tumor specific cytotoxic T lymphocyte responses.

    Directory of Open Access Journals (Sweden)

    Li-Xin Wang

    Full Text Available Lack of immunogenicity of cancer cells has been considered a major reason for their failure in induction of a tumor specific T cell response. In this paper, we present evidence that decitabine (DAC, a DNA methylation inhibitor that is currently used for the treatment of myelodysplastic syndrome (MDS, acute myeloid leukemia (AML and other malignant neoplasms, is capable of eliciting an anti-tumor cytotoxic T lymphocyte (CTL response in mouse EL4 tumor model. C57BL/6 mice with established EL4 tumors were treated with DAC (1.0 mg/kg body weight once daily for 5 days. We found that DAC treatment resulted in infiltration of IFN-γ producing T lymphocytes into tumors and caused tumor rejection. Depletion of CD8(+, but not CD4(+ T cells resumed tumor growth. DAC-induced CTL response appeared to be elicited by the induction of CD80 expression on tumor cells. Epigenetic evidence suggests that DAC induces CD80 expression in EL4 cells via demethylation of CpG dinucleotide sites in the promoter of CD80 gene. In addition, we also showed that a transient, low-dose DAC treatment can induce CD80 gene expression in a variety of human cancer cells. This study provides the first evidence that epigenetic modulation can induce the expression of a major T cell co-stimulatory molecule on cancer cells, which can overcome immune tolerance, and induce an efficient anti-tumor CTL response. The results have important implications in designing DAC-based cancer immunotherapy.

  2. Cytotoxic Effect of Iron Oxide Nanoparticles on Mouse Embryonic Stem Cells by MTT Assay

    Directory of Open Access Journals (Sweden)

    Homa Mohseni Kouchesfehani


    Full Text Available Background: Despite the wide range of applications, there is a serious lack of information on the impact of the nanoparticles on human health and the environment. The present study was done to determine the range of dangerous concentrations of iron oxide nanoparticle and their effects on mouse embryonic stem cells. Methods: Iron oxide nanoparticles with less than 20 nanometers diameter were encapsulated by a PEG-phospholipid. The suspension of iron oxide nanoparticles was prepared using the culture media and cell viability was determined by MTT assay. Results: MTT assay was used to examine the cytotoxicity of iron oxide nanoparticle s. Royan B1 cells were treated with medium containing different concentrations (10, 20, 30, 40, 50, and 60µg/ml of the iron oxide nanoparticle. Cell viability was determined at 12 and 24 hours after treatment which showed significant decreases when concentration and time period increased. Conclusion: The main mechanism of nanoparticles action is still unknown, but in vivo and in vitro studies in different environments suggest that they are capable of producing reactive oxygen species (ROS. Therefore, they may have an effect on the concentration of intracellular calcium, activation of transcription factors, and changes in cytokine. The results of this study show that the higher concentration and duration of treatment of cells with iron oxide nanoparticles increase the rate of cell death.

  3. DNA repair capacity of cultured human lymphocytes exposed to mutagens measured by the comet assay and array expression analysis. (United States)

    Bausinger, Julia; Speit, Günter


    Repair of mutagen-induced DNA lesions during transportation, storage and cultivation of lymphocytes may have a significant impact on results obtained in human biomonitoring after occupational and environmental exposure of human populations to genotoxic chemicals. Using the comet assay in combination with the repair inhibitor aphidicolin and array gene expression analysis of 92 DNA repair genes, we investigated the repair of DNA lesions induced by methyl methanesulfonate (MMS) and benzo[a]pyrenediolepoxide (BPDE) in phytohaemagglutinin (PHA)-stimulated cultured human lymphocytes in the time segment before replication. The comet assay indicated fast repair of MMS-induced damage during the first hours of cultivation. In contrast, removal of BPDE-induced lesions was slower and significant amounts of damage seem to persist until S-phase. Gene expression analysis revealed that PHA stimulation had a clear effect on gene regulation in lymphocytes already during the first 18h of cultivation. Under the conditions of this study, genotoxic concentrations of MMS did not induce significant changes in gene expression. In contrast, exposure to BPDE led to altered expression of several genes in a time- and concentration-related manner. Of the significantly up-regulated genes, only two genes (XPA and XPC) were directly related to nucleotide excision repair. Our results suggest that PHA stimulation of human lymphocytes influences the expression of DNA repair genes in human lymphocytes. The effect of induced DNA damage on gene expression is comparatively low and depends on the mutagens used. PHA-stimulated lymphocytes repair induced DNA damage before they start to replicate but the repair activity during the first 18h of cultivation is not affected by changes in the expression of DNA repair genes during this period of time.

  4. Biocompatibility of Poly (L-Lactic Acid) Synthesized In Polymerization Unit By Cytotoxicity And Hemocompatibility Assay And Nanofibers Production


    Xavier, M.V; Macedo, M.F.; Benatti, A. C. B.; Jardini, A.L.; Rodrigues A.A.; Lopes M.S.; R. MACIEL FILHO; Kharmandayan, P


    The absorbable polyacid is one of the most used and studied materials in tissue engineering. This work synthesized a poly (L-lactic acid) (PLLA) through ring-opening polymerization and produced nanofibers by the electrospinning process. The PLLA was analyzed by FTIR and the cytotoxicity was evaluated by the MTT assay and Live/Dead®. The hemocompatibility was tested by platelet adhesion and hemolytic activity assay. The tests were performed in contact with human mesenchymal cells a...

  5. Screening ToxCast™ Phase I Chemicals in a Mouse Embryonic Stem Cell Adherent Cell Differentiation and Cytotoxicity (ACDC) Assay (United States)

    An Adherent Cell Differentiation and Cytotoxicity (ACDC) in vitro assay with mouse embryonic stem cells was used to screen the ToxCast Phase I chemical library for effects on cellular differentiation and cell number. The U.S. Environmental Protection Agency (EPA) established the ...

  6. Cytotoxicity of artemisinin, a dimer of dihydroartemisinin, artemisitene and eupatoriopicrin as evaluated by the MTT and clonogenic assay

    NARCIS (Netherlands)

    Beekman, AC; Woerdenbag, HJ; Kampinga, HH; Konings, AWT


    Artemisinin and its derivatives possess an endoperoxide bridge, which is thought to lead to the production of free-radical species, The cytotoxicity of some of these agents to a murine Ehrlich ascites (EN19) and a human HeLa S3 cancer cell line was determined using the MTT and the clonogenic assay,

  7. Determination of genotoxic effects of methidathion alkaline hydrolysis in human lymphocytes using the micronucleus assay and square-wave voltammetry. (United States)

    Stivaktakis, Polychronis D; Giannakopoulos, Evangelos; Vlastos, Dimitris; Matthopoulos, Demetrios P


    The interaction of pesticides with environmental factors, such as pH, may result in alterations of their physicochemical properties and should be taken into consideration in regard to their classification. This study investigates the genotoxicity of methidathion and its alkaline hydrolysis by-products in cultured human lymphocytes, using the square-wave voltammetry (square wave-adsorptive cathodic stripping voltammetry (SW-AdCSV) technique) and the cytokinesis block micronucleus assay (CBMN assay). According to the SW-AdCSV data the alkaline hydrolysis of methidathion results in two new molecules, one non-electro-active and a second electro-active which is more genotoxic than methidathion itself in cultured human lymphocytes, inducing higher micronuclei frequencies. The present study confirms the SW-AdCSV technique as a voltammetric method which can successfully simulates the electrodynamics of the cellular membrane.

  8. FLT3-regulated antigens as targets for leukemia-reactive cytotoxic T lymphocytes. (United States)

    Brackertz, B; Conrad, H; Daniel, J; Kast, B; Krönig, H; Busch, D H; Adamski, J; Peschel, C; Bernhard, H


    The FMS-like tyrosine kinase 3 (FLT3) is highly expressed in acute myeloid leukemia (AML). Internal tandem duplications (ITD) of the juxtamembrane domain lead to the constitutive activation of the FLT3 kinase inducing the activation of multiple genes, which may result in the expression of leukemia-associated antigens (LAAs). We analyzed the regulation of LAA in FLT3-wild-type (WT)- and FLT3-ITD(+) myeloid cells to identify potential targets for antigen-specific immunotherapy for AML patients. Antigens, such as PR-3, RHAMM, Survivin, WT-1 and PRAME, were upregulated by constitutively active FLT3-ITD as well as FLT3-WT activated by FLT3 ligand (FL). Cytotoxic T-cell (CTL) clones against PR-3, RHAMM, Survivin and an AML-directed CTL clone recognized AML cell lines and primary AML blasts expressing FLT3-ITD, as well as FLT3-WT(+) myeloid dendritic cells in the presence of FL. Downregulation of FLT3 led to the abolishment of CTL recognition. Comparing our findings concerning LAA upregulation by the FLT3 kinase with those already made for the Bcr-Abl kinase, we found analogies in the LAA expression pattern. Antigens upregulated by both FLT3 and Bcr-Abl may be promising targets for the development of immunotherapeutical approaches against myeloid leukemia of different origin.

  9. Cytotoxic T-lymphocyte-associated protein 4 gene polymorphism is related to rheumatoid arthritis in Egyptian population. (United States)

    Fattah, Shaimaa A; Ghattas, Maivel H; Saleh, Samy M; Abo-Elmatty, Dina M


    Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is a CD28-family receptor expressed on T-cells which suppresses T cell proliferation. CTLA-4 -318C/T polymorphism is involved in regulation of CTLA-4 expression. The study aimed to investigate the genetic association of CTLA-4 -318C/T polymorphism with rheumatoid arthritis (RA) and the activity and severity of the disease in the Egyptian population. A single nucleotide polymorphism (rs5742909) in CTLA-4 was genotyped in 100 RA patients and 100 healthy controls using polymerase chain reaction-restriction fragment length polymorphism. Diagnostic tests were measured for RA patients. The frequency of T allele in RA patients was significantly higher than in the control subjects (p = 0.002). CT and TT genotypes had high C-reactive protein, erythrocyte sedimentation rate and disease activity score 28 while CC genotype had a high rheumatoid factor. A minor allele of CTLA-4 rs5742909 polymorphism was associated with RA and the activity but not the severity of the disease.

  10. Genetic vaccination against the melanocyte lineage-specific antigen gp100 induces cytotoxic T lymphocyte-mediated tumor protection. (United States)

    Schreurs, M W; de Boer, A J; Figdor, C G; Adema, G J


    Melanocyte lineage-specific antigens, such as gp100, have been shown to induce both cellular and humoral immune responses against melanoma. Therefore, these antigens are potential targets for specific antimelanoma immunotherapy. A novel approach to induce both cellular and humoral immunity is genetic vaccination, the injection of antigen-encoding naked plasmid DNA. In a mouse model, we investigated whether genetic vaccination against the human gp100 antigen results in specific antitumor immunity. The results demonstrate that vaccinated mice were protected against a lethal challenge with syngeneic B16 melanoma-expressing human gp100, but not control-transfected B16. Both cytotoxic T cells and IgG specific for human gp100 could be detected in human gp100-vaccinated mice. However, only adoptive transfer of spleen-derived lymphocytes, not of the serum, isolated from protected mice was able to transfer antitumor immunity to nonvaccinated recipients, indicating that CTLs are the predominant effector cells. CTI, lines generated from human gp100-vaccinated mice specifically recognized human gp100. Interestingly, one of the CTL lines cross-reacted between human and mouse gp100, indicating the recognition of a conserved epitope. However, these CTLs did not appear to be involved in the observed tumor protection. Collectively, our results indicate that genetic vaccination can result in a potent antitumor response in vivo and constitutes a potential immunotherapeutic strategy to fight cancer.

  11. DNAM-1 mediates epithelial cell-specific cytotoxicity of aberrant intraepithelial lymphocyte lines from refractory celiac disease type II patients. (United States)

    Tjon, Jennifer M-L; Kooy-Winkelaar, Yvonne M C; Tack, Greetje J; Mommaas, A Mieke; Schreurs, Marco W J; Schilham, Marco W; Mulder, Chris J; van Bergen, Jeroen; Koning, Frits


    In refractory celiac disease (RCD), intestinal epithelial damage persists despite a gluten-free diet. Characteristic for RCD type II (RCD II) is the presence of aberrant surface TCR-CD3(-) intraepithelial lymphocytes (IELs) that can progressively replace normal IELs and eventually give rise to overt lymphoma. Therefore, RCD II is considered a malignant condition that forms an intermediate stage between celiac disease (CD) and overt lymphoma. We demonstrate in this study that surface TCR-CD3(-) IEL lines isolated from three RCD II patients preferentially lyse epithelial cell lines. FACS analysis revealed that DNAM-1 was strongly expressed on the three RCD cell lines, whereas other activating NK cell receptors were not expressed on all three RCD cell lines. Consistent with this finding, cytotoxicity of the RCD cell lines was mediated mainly by DNAM-1 with only a minor role for other activating NK cell receptors. Furthermore, enterocytes isolated from duodenal biopsies expressed DNAM-1 ligands and were lysed by the RCD cell lines ex vivo. Although DNAM-1 on CD8(+) T cells and NK cells is known to mediate lysis of tumor cells, this study provides, to our knowledge, the first evidence that (pre)malignant cells themselves can acquire the ability to lyse epithelial cells via DNAM-1. This study confirms previous work on epithelial lysis by RCD cell lines and identifies a novel mechanism that potentially contributes to the gluten-independent tissue damage in RCD II and RCD-associated lymphoma.

  12. Vitamin B12 and Folic Acid Imbalance Modifies NK Cytotoxicity, Lymphocytes B and Lymphoprolipheration in Aged Rats

    Directory of Open Access Journals (Sweden)

    Teresa Partearroyo


    Full Text Available Different vitamin B12 and folic acid concentrations could exacerbate the immune response. The aim was to evaluate different dietary folic acid and vitamin B12 levels on the immune response in aged rats. Male Sprague Dawley aged rats were assigned to three folic acid groups (deficient, control, supplemented each in absence of vitamin B12 for 30 days. Several parameters of innate and acquired immune responses were measured. Serum and hepatic folate levels increased according to folic acid dietary level, while vitamin B12 levels decreased. There was a significant decrease in natural killer cell-mediated cytotoxicity in the spleen for the vitamin B12 deficient diet and folic acid control diet groups. Significant changes in CD45 lymphocyte subsets were also observed according to dietary imbalance. Lymphoproliferative response to concanavalin A and phytohemagglutinin did not differ significantly between groups. The spleen response to lipopolysaccharide increased significantly, but was unmodified for the other organs. An imbalance between dietary vitamin B12 and folic acid concentrations alters some immunological parameters in aged rats. Therefore, the ratio between folate and vitamin B12 could be as important as their absolute dietary concentrations.

  13. Global Gene Expression Profiling in Interleukin-12-Induced Activation of CD8+ Cytotoxic T Lymphocytes against Mouse Mammary Carcinoma

    Institute of Scientific and Technical Information of China (English)

    Shanjin Cao; Zhaoying Xiang; Xiaojing Ma


    Interleukin-12 (IL-12) is a critical cytokine representing the link between the cellular and humoral branches of host immune defense apparatus. IL-12-induced cytotoxic lymphocyte (CTL) development is a central mechanism in immune responses against intracellular infectious agents as well as malignant growth. However,the molecular basis of tumor-specific CTL responses mediated by IL-12 remains poorly defined. In this study,we addressed this issue in a comprehensive manner to probe into IL-12-induced anti-tumor responses by global gene expression profiling of mRNA expression in CD8+T cells in a transplantable syngeneic mouse mammary carcinoma model treated or not with recombinant IL-12. A strong tumor regression was induced by the IL-12 treatment. An introspection of differential gene expression at an early stage of the IL-12-initiated CTL activation reveals interesting genes and molecular pathways that may account for the marked tumor regression,and is likely to provide a rich source of potential targets for further research and development of effective therapeutic modalities. Cellular & Molecular Immunology. 2004;1(5):357-366.

  14. Immunologic and clinical effects of antibody blockade of cytotoxic T lymphocyte-associated antigen 4 in previously vaccinated cancer patients. (United States)

    Hodi, F Stephen; Butler, Marcus; Oble, Darryl A; Seiden, Michael V; Haluska, Frank G; Kruse, Andrea; Macrae, Suzanne; Nelson, Marybeth; Canning, Christine; Lowy, Israel; Korman, Alan; Lautz, David; Russell, Sara; Jaklitsch, Michael T; Ramaiya, Nikhil; Chen, Teresa C; Neuberg, Donna; Allison, James P; Mihm, Martin C; Dranoff, Glenn


    Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) functions as a negative regulator of endogenous and vaccine-induced antitumor immunity. The administration of fully human anti-CTLA-4 blocking monoclonal antibodies to advanced-cancer patients increases immune-mediated tumor destruction in some subjects. Nonetheless, patients that respond also frequently manifest serious inflammatory pathologies, raising the possibility that the therapeutic and toxic effects of CTLA-4 blockade might be linked. Here we show that periodic infusions of anti-CTLA-4 antibodies after vaccination with irradiated, autologous tumor cells engineered to secrete GM-CSF (GVAX) generate clinically meaningful antitumor immunity without grade 3 or 4 toxicity in a majority of metastatic melanoma patients. The application of this sequential immunotherapy to advanced ovarian carcinoma patients also revealed that tumor destruction and severe inflammatory pathology could be dissociated, although further refinements are required to increase clinical responses and to minimize toxicity in this population. The extent of therapy-induced tumor necrosis was linearly related to the natural logarithm of the ratio of intratumoral CD8(+) effector T cells to FoxP3(+) regulatory T cells (Tregs) in posttreatment biopsies. Together, these findings help clarify the immunologic and clinical effects of CTLA-4 antibody blockade in previously vaccinated patients and raise the possibility that selective targeting of antitumor Tregs may constitute a complementary strategy for combination therapy.

  15. Induction and repair of DNA damage measured by the comet assay in human T lymphocytes separated by immunomagnetic cell sorting. (United States)

    Bausinger, Julia; Speit, Günter


    The comet assay is widely used in human biomonitoring to measure DNA damage in whole blood or isolated peripheral blood mononuclear cells (PBMC) as a marker of exposure to genotoxic agents. Cytogenetic assays with phytohemagglutinin (PHA)-stimulated cultured T lymphocytes are also frequently performed in human biomonitoring. Cytogenetic effects (micronuclei, chromosome aberrations, sister chromatid exchanges) may be induced in vivo but also occur ex vivo during the cultivation of lymphocytes as a consequence of DNA damage present in lymphocytes at the time of sampling. To better understand whether DNA damage measured by the comet assay in PBMC is representative for DNA damage in T cells, we comparatively investigated DNA damage and its repair in PBMC and T cells obtained by immunomagnetic cell sorting. PBMC cultures and T cell cultures were exposed to mutagens with different modes of genotoxic action and DNA damage was measured by the comet assay after the end of a 2h exposure and after 18h post-incubation. The mutagens tested were methyl methanesulfonate (MMS), (±)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), 4-nitroquinoline-1-oxide (4NQO), styrene oxide and potassium bromate. MMS and potassium bromate were also tested by the modified comet assay with formamido pyrimidine glycosylase (FPG) protein. The results indicate that the mutagens tested induce DNA damage in PBMC and T cells in the same range of concentrations and removal of induced DNA lesions occurs to a comparable extent. Based on these results, we conclude that the comet assay with PBMC is suited to predict DNA damage and its removal in T cells.

  16. In vitro generation and characterization of acute myeloid leukemia-reactive CD8 + cytotoxic T-lymphocyte clones from healthy donors


    Distler, Eva


    Donor-derived CD8+ cytotoxic T lymphocytes (CTLs) eliminating host leukemic cells mediate curative graft-versus-leukemia (GVL) reactions after allogeneic hematopoietic stem cell transplantation (HSCT). The leukemia-reactive CTLs recognize hematopoiesis-restricted or broadly expressed minor histocompatibility and leukemia-associated peptide antigens that are presented by human leukocyte antigen (HLA) class I molecules on recipient cells. The development of allogeneic CTL therapy in acute myelo...

  17. Cytotoxic-T-Lymphocyte-Mediated Elimination of Target Cells Transduced with Engineered Adeno-Associated Virus Type 2 Vector In Vivo▿


    Li, Chengwen; Hirsch, Matt; DiPrimio, Nina; Asokan, Aravind; Goudy, Kevin; Tisch, Roland; Samulski, R. Jude


    A recent clinical trial in patients with hemophilia B has suggested that adeno-associated virus (AAV) capsid-specific cytotoxic T lymphocytes (CTLs) eliminated AAV-transduced hepatocytes and resulted in therapeutic failure. AAV capsids elicit a CTL response in animal models; however, these capsid-specific CTLs fail to kill AAV-transduced target cells in mice. To better model the human clinical trial data in mice, we introduced an immunodominant epitope derived from ovalbumin (OVA; SIINFEKL) i...

  18. Why do cytotoxic T lymphocytes fail to eliminate hepatitis C virus? Lessons from studies using major histocompatibility complex class I peptide tetramers. (United States)

    Lechner, F; Sullivan, J; Spiegel, H; Nixon, D F; Ferrari, B; Davis, A; Borkowsky, B; Pollack, H; Barnes, E; Dusheiko, G; Klenerman, P


    Hepatitis C virus (HCV) infection is a major public health problem, affecting an estimated 3% of the world's population, and over 10% in some countries. Infection in most cases becomes persistent, and can lead to hepatic inflammation, fibrosis and liver failure. The T lymphocyte reponse, in particular that mediated by cytotoxic T lymphocytes (CTLs), is likely to be involved in determining the outcome of infection, although its overall role is not clear. The use of major histocompatibility complex (MHC) class I peptide tetrameric complexes (tetramers) to study antiviral CTL responses has revolutionized our approach to the study of human infection. We have used a panel of MHC class I tetramers to analyse immune responses in HCV-infected individuals at various stages of disease. We find that the CTL response against HCV is vigorous in its early phases but dwindles over time both in terms of lymphocyte number and function. A number of potential explanations for this 'CTL failure' are discussed.

  19. Different cytotoxicity responses to antimicrobial nanosilver coatings when comparing extract-based and direct-contact assays. (United States)

    Sussman, Eric M; Casey, Brendan J; Dutta, Debargh; Dair, Benita J


    This study was performed to understand how the choice of cytotoxicity assay format affects the observed biocompatibility of nanosilver (nAg). nAg coatings are physical coatings containing silver (Ag) that have feature sizes of 100 nm or less, often in the form of nanoparticles or grains. They are used on medical devices to prevent infection, but in spite of this intended benefit, observations of potential cytotoxicity from nAg have been reported in numerous published studies. For medical device regulation, cytotoxicity testing is part of a biocompatibility evaluation, in which specific test methods are chosen based on the technological characteristics and intended use of a device. For this study, nAg-coated tissue culture polystyrene surfaces were prepared using magnetron sputter coating, resulting in nAg films of 0.2 to 311 µg cm(-2) Ag. These coatings exhibited nanometer-scale morphologies and demonstrated a > 4log10 reduction in Escherichia coli viability. It was observed that extracts of nAg caused no cytotoxicity to L929 mouse fibroblasts, but cells cultured directly on nAg coatings (direct-contact assay format) showed a dose-dependent reduction in viability by up to 100% (P < 0.001). Results using inductively coupled plasma mass spectrometry to measure Ag release suggested that extracts of nAg are not toxic because the dissolved Ag in those samples becomes less cytotoxic over time, probably owing to the reaction with cell culture media and serum (six-fold cytotoxicity reductions observed over a 24-h period). These findings highlight the potential value of direct-contact cytotoxicity testing for nAg in predicting biological interactions with cells or tissue in vivo.

  20. Liquid crystal based sensors monitoring lipase activity: a new rapid and sensitive method for cytotoxicity assays. (United States)

    Hussain, Zakir; Zafiu, Christian; Küpcü, Seta; Pivetta, Lucineia; Hollfelder, Nadine; Masutani, Akira; Kilickiran, Pinar; Sinner, Eva-Kathrin


    In this work we present liquid crystal (LC) based sensor devices to monitor cell viability. The sensing layer is composed by the LC and a planar monolayer of phospholipids. In the presence of minute traces of phospholipases, which hydrolyze enzymatically phospholipids, the LC-lipid interface is disintegrated. This event causes a change in orientation of the LC, which was followed in a polarized microscope. The lipase activity can be used to measure the cell viability, since members of this enzyme family are released by cells, as they undergo necrosis. The described sensor was used to monitor the presence of the lipases released from three different cell lines, which were either exposed to highly cytotoxic model compounds (sodium azide and paracetamol) or subjected to freeze-thaw cycles to induce cell death by a non-chemical based inducer for apoptosis, such as temperature. Finally, the comparison of lipase activity detected by a state-of-the-art fluorescence assay to the LC based system resulted in the superiority of the LC system concerning incubation time and sensitivity.

  1. Size- and coating-dependent cytotoxicity and genotoxicity of silver nanoparticles evaluated using in vitro standard assays. (United States)

    Guo, Xiaoqing; Li, Yan; Yan, Jian; Ingle, Taylor; Jones, Margie Yvonne; Mei, Nan; Boudreau, Mary D; Cunningham, Candice K; Abbas, Mazhar; Paredes, Angel M; Zhou, Tong; Moore, Martha M; Howard, Paul C; Chen, Tao


    The physicochemical characteristics of silver nanoparticles (AgNPs) may greatly alter their toxicological potential. To explore the effects of size and coating on the cytotoxicity and genotoxicity of AgNPs, six different types of AgNPs, having three different sizes and two different coatings, were investigated using the Ames test, mouse lymphoma assay (MLA) and in vitro micronucleus assay. The genotoxicities of silver acetate and silver nitrate were evaluated to compare the genotoxicity of nanosilver to that of ionic silver. The Ames test produced inconclusive results for all types of the silver materials due to the high toxicity of silver to the test bacteria and the lack of entry of the nanoparticles into the cells. Treatment of L5718Y cells with AgNPs and ionic silver resulted in concentration-dependent cytotoxicity, mutagenicity in the Tk gene and the induction of micronuclei from exposure to nearly every type of the silver materials. Treatment of TK6 cells with these silver materials also resulted in concentration-dependent cytotoxicity and significantly increased micronucleus frequency. With both the MLA and micronucleus assays, the smaller the AgNPs, the greater the cytotoxicity and genotoxicity. The coatings had less effect on the relative genotoxicity of AgNPs than the particle size. Loss of heterozygosity analysis of the induced Tk mutants indicated that the types of mutations induced by AgNPs were different from those of ionic silver. These results suggest that AgNPs induce cytotoxicity and genotoxicity in a size- and coating-dependent manner. Furthermore, while the MLA and in vitro micronucleus assay (in both types of cells) are useful to quantitatively measure the genotoxic potencies of AgNPs, the Ames test cannot.

  2. Consequences of cytotoxic T lymphocyte interaction with major histocompatibility complex class I-expressing neurons in vivo. (United States)

    Rall, G F; Mucke, L; Oldstone, M B


    Neurons have evolved strategies to evade immune surveillance that include an inability to synthesize the heavy chain of the class I major histocompatibility complex (MHC), proteins that are necessary for cytotoxic T lymphocyte (CTL) recognition of target cells. Multiple viruses have taken advantage of the lack of CTL-mediated recognition and killing of neurons by establishing persistent neuronal infections and thereby escaping attack by antiviral CTL. We have expressed a class I MHC molecule (Db) in neurons of transgenic mice using the neuron-specific enolase (NSE) promoter to determine the pathogenic consequences of CTL recognition of virally infected, MHC-expressing central nervous system (CNS) neurons. The NSE-Db transgene was expressed in H-2b founder mice, and transgene-derived messenger RNA was detected by reverse transcriptase-polymerase chain reaction in transgenic brains from several lines. Purified primary neurons from transgenic but not from nontransgenic mice adhered to coverslips coated with a conformation-dependent monoclonal antibody directed against the Dv molecule and presented viral peptide to CTL in an MHC-restricted manner, indicating that the Db molecule was expressed on transgenic neurons in a functional form. Transgenic mice infected with the neurotropic lymphocytic choriomeningitis virus (LCMV) and given anti-LCMV, MHC-restricted CTL displayed a high morbidity and mortality when compared with controls receiving MHC-mismatched CTL or expressing alternative transgenes. After CTL transfer, transgenic brains showed an increased number of CD8+ cells compared with nontransgenic controls as well as an increased rate of clearance of infectious virus from the CNS. Additionally, an increase in blood-brain barrier permeability was detected during viral clearance in NSE-Db transgenic mice and lasted several months after clearance of virus from neurons. In contrast, LCMV-infected, nontransgenic littermates and mice expressing other gene products from the

  3. Role of anti-human lymphocyte culture cytotoxic antibodies in recurrent spontaneous pregnancy loss women

    Directory of Open Access Journals (Sweden)

    Shankarkumar Umapathy


    Full Text Available Background : Recurrent spontaneous pregnancy (RSA is defined as a sequence of three or more consecutive spontaneous abortions. One of the major causes of RSA is immunological where alloimmune antibodies develop towards human leucocyte antigen (HLA antigens. Earlier research had suggested that anti-HLA antibodies are produced in normal women; studies have been reported that normal pregnant women develop anti-HLA antibodies, mostly after 20-28 weeks of gestation. Aim : To evaluate the role of anti-HLA antibodies in RSA patients Materials and Methods : A total of 80 randomly selected couples with unexplained three or more RSA and control group of 50 normal pregnant women were screened for anti-HLA A and B antibodies. The anti-HLA antibodies were analyzed following the standard two-stage NIH microlymphocytotoxicity assay. Results : In our study group a high frequency of anti-HLA antibodies among women with RSA (26.25% was detected compared to normal pregnant women (8.0%. Most of the sera showed HLA-A and HLA-B antibodies which had high titer, up to a dilution of 1: 4096. Conclusion : This incidence of high anti-HLA antibodies in RSA women during early weeks of gestation may explain the recurrent pregnancy loss.

  4. Prediction and identification of mouse cytotoxic T lymphocyte epitopes in Ebola virus glycoproteins

    Directory of Open Access Journals (Sweden)

    Wu Shipo


    Full Text Available Abstract Background Ebola viruses (EBOVs cause severe hemorrhagic fever with a high mortality rate. At present, there are no licensed vaccines or efficient therapies to combat EBOV infection. Previous studies have shown that both humoral and cellular immune responses are crucial for controlling Ebola infection. CD8+ T cells play an important role in mediating vaccine-induced protective immunity. The objective of this study was to identify H-2d-specific T cell epitopes in EBOV glycoproteins (GPs. Results Computer-assisted algorithms were used to predict H-2d-specific T cell epitopes in two species of EBOV (Sudan and Zaire GP. The predicted peptides were synthesized and identified in BALB/c mice immunized with replication-deficient adenovirus vectors expressing the EBOV GP. Enzyme-linked immunospot assays and intracellular cytokine staining showed that the peptides RPHTPQFLF (Sudan EBOV, GPCAGDFAF and LYDRLASTV (Zaire EBOV could stimulate splenoctyes in immunized mice to produce large amounts of interferon-gamma. Conclusion Three peptides within the GPs of two EBOV strains were identified as T cell epitopes. The identification of these epitopes should facilitate the evaluation of vaccines based on the Ebola virus glycoprotein in a BALB/c mouse model.

  5. 腺病毒介导多基因对大鼠脾淋巴细胞毒作用的影响%Effect of adenovirus-mediated multigenes on cytotoxicity of rat spleen lymphocyte in vitro

    Institute of Scientific and Technical Information of China (English)

    王征旭; 何振平; 吴祖泽


    Objective To investigate the changes of the cytotoxicity of ratspleen lymphocyte and the level of IL-2 secreted by human T lymphocyte after the induction of adenovirus-mediated multigenes (Ad-multigenes, containing p53, GM-CSF, B7-1, IL-2 genes). Methods After human lymphocytes of peripheral blood and tumor cells were cultured together, the level of IL-2 secreted by T lymphocytes was determined after they were stimulated by liver cancer cells with pre-transfer of Ad-multigenes in vitro by ELISA. The change of the immunogenicity of rat carcinosarcoma cell Walker 256 transduced with multigenes was studied by cytotoxicity assay of rat spleen lymphocytes. Results The level of IL-2 secreted by peripheral blood T lymphocytes was increased in vitro after the T cells were co-cultivated with Ad-multigene-transducted liver cancer cells. Stimulated by Ad-multigene-transducted Walker 256 cells, the cytotoxicity activities of rat spleen lymphocyte were significantly elevated. Conclusion The immunogenicity of rat carcinosarcoma cell Walker 256 is enhanced, and the IL-2 production level which was secreted by T lymphocyte is increased after the mediation of Ad-multigenes.%目的 研究含多基因(p53、GM-CSF、B7-1、IL-2)的重组腺病毒载体Ad-multigenes,对大鼠脾脏淋巴细胞毒作用的影响及对淋巴细胞分泌IL-2的刺激作用。方法 应用人外周血淋巴细胞和肿瘤细胞混合培养,分析导入目的基因的肝癌细胞系体外刺激人T淋巴细胞分泌IL-2的作用;利用大鼠脾淋巴细胞杀伤活性试验,分析导入目的基因的大鼠癌肉瘤Walker256细胞,其免疫原性的变化。结果 导入Ad-multigenes的肝癌细胞系体外刺激人外周血T淋巴细胞分泌IL-2的水平增加;导入Ad-multigenes的大鼠Walker256细胞,能增强大鼠脾脏淋巴细胞的杀亲本瘤细胞活性。结论 腺病毒介导多基因Ad-multigenes,能增强大鼠癌肉瘤Walker256细胞的免疫原性,和T细胞分泌IL-2的水平增加。

  6. Identification of Immunogenic Cytotoxic T Lymphocyte Epitopes Containing Drug Resistance Mutations in Antiretroviral Treatment-Naive HIV-Infected Individuals.

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    Juan Blanco-Heredia

    Full Text Available Therapeutic HIV vaccines may prove helpful to intensify antiretroviral treatment (ART efficacy and may be an integral part of future cure strategies.We examined IFN-gamma ELISpot responses to a panel of 218 HIV clade B consensus-based HIV protease-reverse transcriptase peptides, designed to mimic previously described and predicted cytotoxic T lymphocyte epitopes overlapping drug resistance (DR positions, that either included the consensus sequence or the DR variant sequence, in 49 ART-naïve HIV-infected individuals. Next generation sequencing was used to assess the presence of minority DR variants in circulating viral populations.Although a wide spectrum of differential magnitudes of response to DR vs. WT peptide pairs was observed, responses to DR peptides were frequent and strong in the study cohort. No difference between the median magnitudes of response to DR vs. WT peptides was observed. Interestingly, of the 22 peptides that were recognized by >15% of the participants, two-thirds (64% corresponded to DR peptides. When analysing responses per peptide pair per individual, responses to only WT (median 4 pairs/individual or DR (median 6 pairs/individual were more common than responses to both WT and DR (median 2 pairs/individual; p<0.001. While the presence of ELISpot responses to WT peptides was frequently associated with the presence of the corresponding peptide sequence in the patient's virus (mean 68% of cases, responses to DR peptides were generally not associated with the presence of DR mutations in the viral population, even at low frequencies (mean 1.4% of cases; p = 0.0002.Our data suggests that DR peptides are frequently immunogenic and raises the potential benefit of broadening the antigens included in a therapeutic vaccine approach to immunogenic epitopes containing common DR sequences. Further studies are needed to assess the quality of responses elicited by DR peptides.

  7. Discovery of a Good Responder Subtype of Esophageal Squamous Cell Carcinoma with Cytotoxic T-Lymphocyte Signatures Activated by Chemoradiotherapy.

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    Yosuke Tanaka

    Full Text Available Definitive chemoradiotherapy (CRT is a less invasive therapy for esophageal squamous cell carcinoma (ESCC. Five-year survival rate of locally advanced ESCC patients by definitive CRT were 37%. We previously reported that tumor-specific cytotoxic T-lymphocyte (CTL activation signatures were preferentially found in long-term survivors. However, it is unknown whether the CTL activation is actually driven by CRT. We compared gene expression profiles among pre- and post-treatment biopsy specimens of 30 ESCC patients and 121 pre-treatment ESCC biopsy specimens. In the complete response (CR cases, 999 overexpressed genes including at least 234 tumor-specific CTL-activation associated genes such as IFNG, PRF1, and GZMB, were found in post-treatment biopsy specimens. Clustering analysis using expression profiles of these 234 genes allowed us to distinguish the immune-activated cases, designating them as I-type, from other cases. However, despite the better CR rate in the I-type, overall survival was not significantly better in both these 30 cases and another 121 cases. Further comparative study identified a series of epithelial to mesenchymal transition-related genes overexpressed in the early relapse cases. Importantly, the clinical outcome of CDH2-negative cases in the I-type was significantly better than that of the CDH2-positive cases in the I-type. Furthermore, NK cells, which were activated by neutrophils-producing S100A8/S100A9, and CTLs were suggested to cooperatively enhance the effect of CRT in the CDH2-negative I-type. These results suggested that CTL gene activation may provide a prognostic advantage in ESCCs with epithelial characteristics.

  8. Effective Cytotoxic T Lymphocyte Targeting of Persistent HIV-1 during Antiretroviral Therapy Requires Priming of Naive CD8+ T Cells

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    Kellie N. Smith


    Full Text Available Curing HIV-1 infection will require elimination of persistent cellular reservoirs that harbor latent virus in the face of combination antiretroviral therapy (cART. Proposed immunotherapeutic strategies to cure HIV-1 infection include enhancing lysis of these infected cells by cytotoxic T lymphocytes (CTL. A major challenge in this strategy is overcoming viral immune escape variants that have evaded host immune control. Here we report that naive CD8+ T cells from chronic HIV-1-infected participants on long-term cART can be primed by dendritic cells (DC. These DC must be mature, produce high levels of interleukin 12p70 (IL-12p70, be responsive to CD40 ligand (CD40L, and be loaded with inactivated, autologous HIV-1. These DC-primed CD8+ T cell responders produced high levels of gamma interferon (IFN-γ in response to a broad range of both conserved and variable regions of Gag and effectively killed CD4+ T cell targets that were either infected with the autologous latent reservoir-associated virus or loaded with autologous Gag peptides. In contrast, HIV-1-specific memory CD8+ T cells stimulated with autologous HIV-1-loaded DC produced IFN-γ in response to a narrow range of conserved and variable Gag peptides compared to the primed T cells and most notably, displayed significantly lower cytolytic function. Our findings highlight the need to selectively induce new HIV-1-specific CTL from naive precursors while avoiding activation of existing, dysfunctional memory T cells in potential curative immunotherapeutic strategies for HIV-1 infection.

  9. Autoimmunity Correlates With Tumor Regression in Patients With Metastatic Melanoma Treated With Anti–Cytotoxic T-Lymphocyte Antigen-4 (United States)

    Attia, Peter; Phan, Giao Q.; Maker, Ajay V.; Robinson, Michael R.; Quezado, Martha M.; Yang, James C.; Sherry, Richard M.; Topalian, Suzanne L.; Kammula, Udai S.; Royal, Richard E.; Restifo, Nicholas P.; Haworth, Leah R.; Levy, Catherine; Mavroukakis, Sharon A.; Nichol, Geoff; Yellin, Michael J.; Rosenberg, Steven A.


    Purpose Previously, we reported our experience treating 14 patients with metastatic melanoma using a fully human antibody to cytotoxic T-lymphocyte antigen-4 (anti–CTLA-4) in conjunction with peptide vaccination. We have now treated 56 patients to evaluate two different dose schedules of anti–CTLA-4 and to explore the relationship between autoimmunity and tumor regression. Patients and Methods A total of 56 patients with progressive stage IV melanoma were enrolled onto the study. All had Karnofsky performance status ≥60% with no prior history of autoimmunity. Twenty-nine patients received 3 mg/kg anti–CTLA-4 every 3 weeks, whereas 27 received 3 mg/kg as their initial dose with subsequent doses reduced to 1 mg/kg every 3 weeks. In both cohorts patients received concomitant vaccination with two modified HLA-A*0201-restricted peptides from the gp100 melanoma-associated antigen, gp100:209-217(210M) and gp100:280-288(288V). Results Two patients achieved a complete response (ongoing at 30 and 31 months, respectively) and five patients achieved a partial response (durations of 4, 6, 25+, 26+, and 34+ months, respectively), for an overall objective response rate of 13%. Tumor regression was seen in lung, liver, brain, lymph nodes, and subcutaneous sites. Of 14 patients with grade 3/4 autoimmune toxicity, five (36%) experienced a clinical response compared with only two responses in the 42 patients (5%) with no autoimmune toxicity (P = .008). There were no significant differences in response rate or toxicity between the two dose schedules. Conclusion Administration of anti–CTLA-4 monoclonal antibody plus peptide vaccination can cause durable objective responses, which correlate with the induction of autoimmunity, in patients with metastatic melanoma. PMID:16087944

  10. Nucleobase-Based Barbiturates: Their Protective Effect against DNA Damage Induced by Bleomycin-Iron, Antioxidant, and Lymphocyte Transformation Assay

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    Bhaveshkumar D. Dhorajiya


    Full Text Available A number of nucleobase-based barbiturates have been synthesized by combination of nucleic acid bases and heterocyclic amines and barbituric acid derivatives through green and efficient multicomponent route and one pot reaction. This approach was accomplished efficiently using aqueous medium to give the corresponding products in high yield. The newly synthesized compounds were characterized by spectral analysis (FT-IR, 1H NMR, 13C NMR, HMBC, and UV spectroscopy and elemental analysis. Representative of all synthesized compounds was tested and evaluated for antioxidant, bleomycin-dependent DNA damage, and Lymphocyte Transformation studies. Compounds TBC > TBA > TBG showed highest lymphocyte transformation assay, TBC > TBA > BG showed inhibitory antioxidant activity using ABTS methods, and TBC > BPA > BAMT > TBA > 1, 3-TBA manifested the best protective effect against DNA damage induced by bleomycin.

  11. Silver nanoparticles: Significance of physicochemical properties and assay interference on the interpretation of in vitro cytotoxicity studies. (United States)

    Riaz Ahmed, Kausar B; Nagy, Amber M; Brown, Ronald P; Zhang, Qin; Malghan, Subhas G; Goering, Peter L


    Silver nanoparticles (AgNPs) have generated a great deal of interest in the research, consumer product, and medical product communities due to their antimicrobial and anti-biofouling properties. However, in addition to their antimicrobial action, concerns have been expressed about the potential adverse human health effects of AgNPs. In vitro cytotoxicity studies often are used to characterize the biological response to AgNPs and the results of these studies may be used to identify hazards associated with exposure to AgNPs. Various factors, such as nanomaterial size (diameter), surface area, surface charge, redox potential, surface functionalization, and composition play a role in the development of toxicity in in vitro test systems. In addition, the interference of AgNPs with in vitro cytotoxicity assays may result in false negative or false positive results in some in vitro biological tests. The goal of this review is to: 1) summarize the impact of physical-chemical parameters, including size, shape, surface chemistry and aggregate formation on the in vitro cytotoxic effects of AgNPs; and 2) explore the nature of AgNPs interference in in vitro cytotoxicity assays. Published by Elsevier Ltd.

  12. The modified FACS calcein AM retention assay: A high throughput flow cytometer based method to measure cytotoxicity. (United States)

    Gillissen, M A; Yasuda, E; de Jong, G; Levie, S E; Go, D; Spits, H; van Helden, P M; Hazenberg, M D


    Current methods to determine cellular cytotoxicity in vitro are hampered by background signals that are caused by auto-fluorescent target and effector cells and by non-specific cell death. We combined and adjusted existing cell viability assays to develop a method that allows for highly reproducible, accurate, single cell analysis by high throughput FACS, in which non-specific cell death is corrected for. In this assay the number of living, calcein AM labeled cells that are green fluorescent are quantified by adding a fixed number of unlabeled calibration beads to the analysis. Using this modified FACS calcein AM retention method, we found EC50 values to be highly reproducible and considerably lower compared to EC50 values obtained by conventional assays, displaying the high sensitivity of this assay.

  13. Association of Cytotoxic T-Lymphocyte Antigen 4 (CTLA4 and Thyroglobulin (TG Genetic Variants with Autoimmune Hypothyroidism.

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    Hinal Patel

    Full Text Available Autoimmune hypothyroidism is known to be caused by immune responses related to the thyroid gland and its immunological feature includes presence of autoimmune antibodies. Therefore the aim was to analyze presence of anti-TPO antibodies in hypothyroidism patients in Gujarat. Cytotoxic T-Lymphocyte Antigen 4 (CTLA4 is one of the susceptibility genes for various autoimmune diseases. Hence, exon1 +49A/G and 3'UTR CT60A/G single nucleotide polymorphisms (SNPs in CTLA4 and its mRNA expression levels were investigated in autoimmune hypothyroidism patients. Thyroglobulin (TG is known to be associated with autoimmune thyroid disorders and thus exon 33 (E33 SNP in TG was investigated. We analyzed the presence of anti-TPO antibodies in the plasma samples of 84 hypothyroidism patients and 62 controls by ELISA. PCR-RFLP technique was used for genotyping of polymorphisms. sCTLA4 and flCTLA4 mRNA expression levels were assessed by real time PCR. 59.52% of hypothyroid patients had anti-TPO antibodies in their circulation. The genotype and allele frequencies differed significantly for +49A/G (p = 0.0004 for +49AG, p = 0.0019 for +49GG & p = 0.0004 for allele, CT60 (p = 0.0110 for CT60AG, p = 0.0005 for CT60GG & p<0.0001 for allele and TG E33 (p = 0.0003 for E33TC p<0.0001 for E33CC& p<0.0001 for allele SNPs between patients and controls. Patients had significantly decreased mRNA levels of both sCTLA4 (p = 0.0017 and flCTLA4 (p<0.0001 compared to controls. +49A/G and CT60 polymorphisms of CTLA4 were in moderate linkage disequilibrium. Logistic regression analysis indicated significant association of CT49A/G, CT60A/G and TG exon 33 polymorphisms with susceptibility to autoimmune hypothyroidism when adjusted for age and gender. Our results suggest +49A/G and CT60 polymorphism of CTLA4 and E33 polymorphism of TG may be genetic risk factors for autoimmune hypothyroidism susceptibility and down regulation of both forms of CTLA4 advocates the crucial role of CTLA4 in

  14. The effect of inhibited replication on DNA migration in the comet assay in relation to cytotoxicity and clastogenicity. (United States)

    Speit, Günter; Schütz, Petra


    The DNA-replication inhibitors aphidicolin (APC) and hydroxyurea (HU) were tested for their ability to induce effects on DNA in the in vitro alkaline comet assay with V79 cells. APC concentrations up to 15 microM and HU concentrations up to 500 microM did not significantly increase the extent of DNA migration after treatment during 4h. Treatment for 18 h, however, led to inconsistently significant increase in DNA migration. These increases in DNA migration were accompanied by severe cell-cycle disturbances, cytotoxic effects (reduced population doubling and reduced mitotic index) and increased frequencies of cells with chromosome aberrations. The results indicate that substances with such secondary effects on DNA (in contrast to agents that directly damage DNA) only induce effects in the comet assay after prolonged exposure, together with cytotoxic effects. We conclude that slight inhibition of DNA replication and cell-cycle delay per se do not cause significant effects in the in vitro comet assay under standard test conditions. Furthermore, the in vitro comet assay seems to be less sensitive towards this type of secondary DNA effects than the in vitro chromosome aberration test.

  15. Applying generalized hydrophobicity scale of amino acids to quantitative prediction of human leukocyte antigen-A*0201-restricted cytotoxic T lymphocyte epitope

    Institute of Scientific and Technical Information of China (English)

    ZHOU Peng; TIAN Feifei; ZHANG Mengjun; LI Zhiliang


    Derived from 149 hydrophobic factors of 20 natural amino acids, a novel amino acid descriptor termed as generalized hydrophobicity scale (GH-scale) was proposed by principal component analysis (PCA). Via genetic algorithm-partial least square (GPLS) method, quantitative structure-activity relationship (QSAR) model was constructed by GH-scale for 152 human leukocyte antigen (HLA)-A*0201-restricted cytotoxic T lymphocyte (CTL) epitopes with the model estimated and cross-validated correlative coefficients of R2 = 0.813 and Q2 = 0.725, respectively. It was indicated that hydrophobic interaction played an important role in HLA-A*0201-CTL interaction, prominently at anchor residues.

  16. A single nine-amino acid peptide induces virus-specific, CD8+ human cytotoxic T lymphocyte clones of heterogeneous serotype specificities



    It is generally accepted that virus-specific CD8+ cytotoxic T lymphocytes (CTLs) recognize nine-amino acid peptides in conjunction with HLA class I molecules. We recently reported that dengue virus- specific CD8+ CTLs of two different serotype specificities, which were established by stimulation with dengue virus, recognize a single nine- amino acid peptide of the nonstructural protein NS3 of dengue virus type 4 (D4V) in an HLA-B35-restricted fashion. To further analyze the relationships betw...

  17. Attachment of an anti-receptor antibody to non-target cells renders them susceptible to lysis by a clone of cytotoxic T lymphocytes.


    Kranz, D M; Tonegawa, S.; Eisen, H N


    The molecular basis for the dependence of antigen recognition by T cells on products of the major histocompatibility complex (MHC) is unknown, and the antigenic structures that are actually bound by T-cell receptors are ill-defined. In this study, we asked whether a monoclonal antibody (mAb) that reacts with the T-cell receptor of a clone of murine cytotoxic T lymphocytes (CTL) and not with the receptors of other CTL clones can substitute for that clone's natural ligand in specific cytolytic ...

  18. In vitro assessment of genotoxic effects of electric arc furnace dust on human lymphocytes using the alkaline comet assay. (United States)

    Garaj-Vrhovac, Vera; Orescanin, Visnja; Ruk, Damir; Gajski, Goran


    In vitro genotoxic effects of leachates of electric arc furnace dust (EAFD) on human peripheral lymphocytes, assessed prior and following the treatment with a strong alkaline solution were investigated using the alkaline comet assay. Prior and following the treatment, lymphocytes were incubated with leachate of EAFD for 6 and 24 hours at 37 degrees C. Negative controls were also included. Mean values of the tail lengths established in the samples treated with the leachate stemming from the original dust for 6 and 24 hours, were 15.70 microm and 16.78 microm, respectively, as compared to 12.33 microm found in the control sample. Slight, but significant increase in the tail length was also found with the dust treated with a strong alkaline solution (13.37 microm and 13.60 microm). In case of high heavy metal concentrations (the extract of the original furnace dust), the incubation period was revealed to be of significance as well. The obtained results lead to the conclusion that alkaline comet assay could be used as a rapid, sensitive and low-cost tool when assessing genotoxicity of various waste materials, such as leachates of the electric arc furnace dust.

  19. Comparison of five different in vitro assays for assessment of sodium metavanadate cytotoxicity in Chinese hamster ovary cells (CHO-K1 line). (United States)

    Zwolak, Iwona


    This investigation was undertaken to compare five different in vitro cytotoxicity assays for their power in revealing vanadium-mediated toxicity in Chinese hamster ovary (CHO)-K1 cells. The cells were exposed to sodium metavanadate (NaVO(3)) in the range of 10-1000 µM for 24 h and thereafter the cytotoxic effects of NaVO(3) were measured by colorimetric in vitro assays: the neutral red (NR) test, the 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt (XTT) assay, the resazurin assay, the sulforhodamine B (SR-B) assay, and by microscopic assessment of cell viability using the trypan blue (TB) staining method. Among the assays used, the NR test was the most sensitive, since it revealed metavanadate cytotoxicity at the lowest NaVO(3) dose (=50 µM). Also, NaVO(3) cytotoxicity expressed as inhibitory concentration (IC) showed the lowest values for the NR test. Three other tests XTT, resazurin, and SR-B assays showed intermediate sensitivity revealing the cytotoxicity of NaVO(3) at 100 µM. The corresponding IC10 and IC50 values calculated for the XTT, resazurin, and SR-B tests were similar. The TB staining method was the least sensitive, since it recorded metavanadate cytotoxicity at the highest NaVO(3) concentration tested (=600 µM). Based on the cytotoxicity end points measured with the above assays, it can be concluded that lysosomal/Golgi apparatus damage (measured by NR assay) may be the primary effect of NaVO(3) on CHO-K1 cells. The disintegration of mitochondria (assessed with the XTT and resazurin assays) probably follows lysosomal impairment. Plasma membrane permeability (staining with TB) occurs at a late stage of NaVO(3)-induced cytotoxicity on CHO-K1 cells. The results obtained in this research work show that the NR test can be recommended as a very sensitive assay for the assessment of NaVO(3) cytotoxicity in the CHO-K1 cell culture model. Considering the convenience of assay performance along with adequate sensitivity

  20. Increased breadth and depth of cytotoxic T lymphocytes responses against HIV-1-B Nef by inclusion of epitope variant sequences.

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    Morgane Rolland

    Full Text Available Different vaccine approaches cope with HIV-1 diversity, ranging from centralized(1-4 to variability-encompassing(5-7 antigens. For all these strategies, a concern remains: how does HIV-1 diversity impact epitope recognition by the immune system? We studied the relationship between HIV-1 diversity and CD8(+ T Lymphocytes (CTL targeting of HIV-1 subtype B Nef using 944 peptides (10-mers overlapping by nine amino acids (AA that corresponded to consensus peptides and their most common variants in the HIV-1-B virus population. IFN-γ ELISpot assays were performed using freshly isolated PBMC from 26 HIV-1-infected persons. Three hundred and fifty peptides elicited a response in at least one individual. Individuals targeted a median of 7 discrete regions. Overall, 33% of responses were directed against viral variants but not elicited against consensus-based test peptides. However, there was no significant relationship between the frequency of a 10-mer in the viral population and either its frequency of recognition (Spearman's correlation coefficient ρ = 0.24 or the magnitude of the responses (ρ = 0.16. We found that peptides with a single mutation compared to the consensus were likely to be recognized (especially if the change was conservative and to elicit responses of similar magnitude as the consensus peptide. Our results indicate that cross-reactivity between rare and frequent variants is likely to play a role in the expansion of CTL responses, and that maximizing antigenic diversity in a vaccine may increase the breadth and depth of CTL responses. However, since there are few obvious preferred pathways to virologic escape, the diversity that may be required to block all potential escape pathways may be too large for a realistic vaccine to accommodate. Furthermore, since peptides were not recognized based on their frequency in the population, it remains unclear by which mechanisms variability-inclusive antigens (i.e., constructs enriched with

  1. Large-scale preparation of human anti-third-party veto cytotoxic T lymphocytes depleted of graft-versus-host reactivity: a new source for graft facilitating cells in bone marrow transplantation. (United States)

    Aviner, Shraga; Yao, Xin; Krauthgamer, Rita; Gan, Yehudit; Goren-Arbel, Rinat; Klein, Tirza; Tabilio, Antonio; McMannis, John D; Champlin, Richard; Martelli, Massimo F; Bachar-Lustig, Esther; Reisner, Yair


    Induction of donor type chimerism in mildly prepared hosts without graft-versus-host disease (GvHD) is a most desirable goal in bone morrow transplantation. We have recently demonstrated in a mouse model that donor veto cytotoxic T lymphocytes (CTLs) can facilitate the induction of donor type chimerism in sublethally irradiated recipients without causing GvHD if they are effectively depleted of alloreactivity against host cells by means of stimulation against a third party. We extend this approach to human cells, by preparing CTLs in two major steps: primary culture in the absence of interleukin 2, leading to death by neglect of antihost clones, and addition of interleukin 2 and subsequent dilution of antihost clones as a consequence of the expansion of the anti-third-party clones. CTLs prepared in this way specifically suppress host cytotoxic T cells directed against antigens of the donor, but not against fourth-party antigens, as demonstrated in a standard (51)Cr release assay. We conclude that human anti-third-party CTLs afford a new source of veto cells that are depleted of potential graft-versus-host-reactive clones. The cells generated by this approach could potentially be used to facilitate engraftment of allogeneic hematopoietic stem cells.

  2. Biocompatibility of Poly (L-Lactic Acid Synthesized In Polymerization Unit By Cytotoxicity And Hemocompatibility Assay And Nanofibers Production

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    Xavier, M.V


    Full Text Available The absorbable polyacid is one of the most used and studied materials in tissue engineering. This work synthesized a poly (L-lactic acid (PLLA through ring-opening polymerization and produced nanofibers by the electrospinning process. The PLLA was analyzed by FTIR and the cytotoxicity was evaluated by the MTT assay and Live/Dead®. The hemocompatibility was tested by platelet adhesion and hemolytic activity assay. The tests were performed in contact with human mesenchymal cells at varying times. The high rates of cell viability and proliferation shown by MTT and Live/Dead® tests demonstrate that this PLLA is a non-toxic material and the hemocompatibility assay revealed that the biomaterial was also biocompatible. It was achieved as well the successful production of electrospinning nanofibers, which can be converted for specific biomedical applications in the future

  3. Combination of two anti-CD5 monoclonal antibodies synergistically induces complement-dependent cytotoxicity of chronic lymphocytic leukaemia cells

    DEFF Research Database (Denmark)

    Klitgaard, Josephine L; Koefoed, Klaus; Geisler, Christian


    secondary effector functions represent an attractive opportunity for CLL treatment. Here, a repertoire of mAbs against human CD5 was generated and tested for ability to induce complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC) both as single m...

  4. Induction of cytotoxic T lymphocyte respones in vivo after immunotherapy with dendritic cells in patients with nasopharyngeal carcinoma

    Institute of Scientific and Technical Information of China (English)



    The aim of the present study was to determine the efficacy of immunotherapy with dendritic cells to elicit EBV-specific CTL-immunity in advanced cases of EBV-positive patients with nasopharyngeal carcinoma (NPC) and to determine the safety and toxicity of this preparation. Nine cases of histologically confirmed patients with NPC undergoing treatment with radiological therapy were enrolled in this study. Dendritic cells, generated in vitro from blood monocytes of patients were cultured and matured with cytokines and then infected with recombinant adenovirus vaccine containing EBV-latent membrane protein-2 (Ad-LMP2). On 9 days' cultivation of cells, the matured DCs were harvested, irradiated with 60Co and then injected intradermally to patients with NPC. The injections were performed 3 times totally. After immunization, the CTL responses were assayed by means of cytotoxicity and epitope-specific IFN-γ production. The results of this trial showed that all patients could tolerate this kind of treatment without any side effect, during which marked increase of LMP2-specific CTL-responses could be demonstrated in 5 patients of this group. And the level of IgA/VCA antibody decreased in 8 of 9 patients, thus accounting for a better prognosis for these patients. All patients will be followed up for another one year. At least, the present work shows that intradermal vaccination with autologous DCs infected with recombinant Ad-LMP2 adenovirus is a safe procedure in NPC patients, in which this procedure can enhance the LMP2-specific CTL responses in patients. These data are encouraging to develop more effective vaccine strategies for the treatment of nasopharyngeal carcinoma.

  5. Flavivirus-cross-reactive, HLA-DR15-restricted epitope on NS3 recognized by human CD4+ CD8- cytotoxic T lymphocyte clones. (United States)

    Kurane, I; Okamoto, Y; Dai, L C; Zeng, L L; Brinton, M A; Ennis, F A


    The role of flavivirus-cross-reactive T lymphocytes in recovery from and pathogenesis of flavivirus infections is not known. In the present paper, we have defined a flavivirus-cross-reactive epitope recognized by two CD4+ CD8- cytotoxic T lymphocyte (CTL) clones, JK4 and JK43. The T cell clones were established from the peripheral blood T lymphocytes of a dengue-4-immune donor, using a limiting-dilution method with dengue-4 antigen. These two T cell clones were cross-reactive for dengue virus types 1, 2, 3 and 4, yellow fever virus and West Nile virus, and recognized NS3 protein. The smallest synthetic peptide recognized by these T cell clones was an identical 9 amino acid peptide which contains amino acids 146 to 154 (VIGLYGNGV) of dengue-4 NS3. HLA-DR15 was the restriction allele for recognition of this epitope by JK4 and JK43. JK4 and JK43 both used T cell receptor V alpha 8, but JK4 used V beta 8 and JK43 used V beta 2. This result indicates that this epitope is recognized by two flavivirus-cross-reactive CD4+ T cell clones which originated from different T cells in vivo.

  6. Definition of an epitope on NS3 recognized by human CD4+ cytotoxic T lymphocyte clones cross-reactive for dengue virus types 2, 3, and 4. (United States)

    Kurane, I; Zeng, L; Brinton, M A; Ennis, F A


    The role of dengue virus-specific serotype-cross-reactive T lymphocytes in recovery from and pathogenesis of dengue virus infections is not known. In the present paper, we have defined a dengue serotype-cross-reactive epitope recognized by two CD4+ CD8- cytotoxic T lymphocyte (CTL) clones, JK36 and JK46. These T cell clones were established from the peripheral blood T lymphocytes of a dengue-3-immune donor, using a limiting dilution method. JK36 and JK46 were cross-reactive for dengue virus types 2, 3, and 4, but not for type 1, and recognized the NS3 protein. The smallest synthetic peptide recognized by JK36 was an 8-amino acid peptide that contains amino acids (aa) 226 to 233 (VVAAEMEE) of NS3. The smallest peptide recognized by JK46 was an 11-amino acid peptide that contains aa 224 to 234 (TRVVAAEMEEA). HLA-DR15 was the restriction allele for recognition of these peptides by both JK36 and JK46. This is the first epitope to be defined that is recognized by human CD4+ CTL cross-reactive for dengue virus types 2, 3, and 4.

  7. Human immune compartment comparisons: Optimization of proliferative assays for blood and gut T lymphocytes. (United States)

    Dock, Jeffrey; Hultin, Lance; Hultin, Patricia; Elliot, Julie; Yang, Otto O; Anton, Peter A; Jamieson, Beth D; Effros, Rita B


    The accumulation of peripheral blood late-differentiated memory CD8 T cells with features of replicative (cellular) senescence, including inability to proliferate in vitro, has been extensively studied. Importantly, the abundance of these cells is directly correlated with increased morbidity and mortality in older persons. Of note, peripheral blood contains only 2% of the total body lymphocyte population. By contrast, the gut-associated lymphoid tissue (GALT) is the most extensive lymphoid organ, housing up to 60% of total body lymphocytes, but has never been assessed with respect to senescence profiles. We report here the development of a method for measuring and comparing proliferative capacity of peripheral blood and gut colorectal mucosa-derived CD8 T cells. The protocol involves a 5-day culture of mononuclear leukocyte populations, from blood and gut colorectal mucosa respectively, labeled with 5-(and 6)-carboxyfluorescein diacetate succinimidyl ester (CFSE) and 5-bromo-2'-deoxyuridine (BrdU) and stimulated with anti-CD2/3/28-linked microbeads. Variables tested and optimized as part of the protocol development include: mode of T cell stimulation, CFSE concentration, inclusion of a second proliferation marker, BrdU, culture duration, initial culture concentration, and inclusion of autologous irradiated feeder cells. Moving forward, this protocol demonstrates a significant advance in the ability of researchers to study compartment-specific differences of in vitro proliferative dynamics of CD8 T cells, as an indicator of replicative senescence and immunological aging. The study's two main novel contributions are (1) Optimization and adaptation of standard proliferative dynamics blood T cell protocols for T cells within the mucosal immune system. (2) Introduction of the novel technique of combining CFSE and BrdU staining to do so.

  8. Artificial antigen-presenting cells expressing AFP(158-166) peptide and interleukin-15 activate AFP-specific cytotoxic T lymphocytes. (United States)

    Sun, Longhao; Guo, Hao; Jiang, Ruoyu; Lu, Li; Liu, Tong; Zhang, Zhixiang; He, Xianghui


    Professional antigen-presenting cells (APCs) are potent generators of tumor antigen-specific cytotoxic T lymphocytes (CTLs) for adoptive immunotherapy; however, generation of APCs is cumbersome, expensive, and subject to the tumor microenvironment. Artificial APCs (aAPCs) have been developed as a cost-effective alternative to APCs. We developed a cellular aAPC that efficiently generated alpha-fetoprotein (AFP)-specific CTLs. We genetically modified the human B cell lymphoma cell line BJAB with a lentiviral vector to establish an aAPC called BA15. The expression of AFP(158-166)-HLA-A*02:01 complex, CD80, CD86, and interleukin (IL)-15 in BA15 cells was assessed. The efficiency of BA15 at generating AFP-specific CTLs and the specific cytotoxicity of CTLs against AFP+ cells were also determined. BA15 cells expressed high levels of AFP(158-166) peptide, HLA-A2, CD80, CD86, and IL-15. BA15 cells also exhibited higher efficiency in generating AFP-specific CTLs than did dendritic cells. These CTLs had greater cytotoxicity against AFP+ hepatocellular carcinoma cells than did CTLs obtained from dendritic cells in vitro and in vivo. Our novel aAPC system could provide a robust platform for the generation of functional AFP-specific CTLs for adoptive immunotherapy of hepatocellular carcinoma.

  9. Lymphocyte transformation assay for C neoformans antigen is not reliable for detecting cellular impairment in patients with Neurocryptococcosis

    Directory of Open Access Journals (Sweden)

    Rocha Katya C


    Full Text Available Abstract Background Cryptococcus neoformans causes meningitis and disseminated infection in healthy individuals, but more commonly in hosts with defective immune responses. Cell-mediated immunity is an important component of the immune response to a great variety of infections, including yeast infections. We aimed to evaluate a specific lymphocyte transformation assay to Cryptococcus neoformans in order to identify immunodeficiency associated to neurocryptococcosis (NCC as primary cause of the mycosis. Methods Healthy volunteers, poultry growers, and HIV-seronegative patients with neurocryptococcosis were tested for cellular immune response. Cryptococcal meningitis was diagnosed by India ink staining of cerebrospinal fluid and cryptococcal antigen test (Immunomycol-Inc, SP, Brazil. Isolated peripheral blood mononuclear cells were stimulated with C. neoformans antigen, C. albicans antigen, and pokeweed mitogen. The amount of 3H-thymidine incorporated was assessed, and the results were expressed as stimulation index (SI and log SI, sensitivity, specificity, and cut-off value (receiver operating characteristics curve. We applied unpaired Student t tests to compare data and considered significant differences for p Results The lymphotoxin alpha showed a low capacity with all the stimuli for classifying patients as responders and non-responders. Lymphotoxin alpha stimulated by heated-killed antigen from patients with neurocryptococcosis was not affected by TCD4+ cell count, and the intensity of response did not correlate with the clinical evolution of neurocryptococcosis. Conclusion Response to lymphocyte transformation assay should be analyzed based on a normal range and using more than one stimulator. The use of a cut-off value to classify patients with neurocryptococcosis is inadequate. Statistical analysis should be based on the log transformation of SI. A more purified antigen for evaluating specific response to C. neoformans is needed.

  10. Assessment of DNA damage in underground coal miners using the cytokinesis-block micronucleus assay in peripheral blood lymphocytes. (United States)

    Sinitsky, Maxim Yu; Minina, Varvara I; Gafarov, Nikolay I; Asanov, Maxim A; Larionov, Aleksey V; Ponasenko, Anastasia V; Volobaev, Valentin P; Druzhinin, Vladimir G


    Coal miners are exposed to coal dust, containing mineral particles, inorganic compounds and polycyclic aromatic hydrocarbons, and to ionizing radiation. These factors can induce oxidative stress and promote inflammation that leads to DNA damage. The aim of this investigation is to analyse the degree of DNA damage in miners working in underground coal mines in Kemerovo Region (Russian Federation) using the cytokinesis-block micronucleus assay (CBMN) in peripheral blood lymphocytes. The exposed group included 143 coal miners (mean age = 50.11±7.36 years; mean length of service in coal mining conditions = 23.26±9.66 years). As a control group, we have used venous blood extracted from 127 healthy non-exposed men. The mean age in this group was 47.67±8.45 years. We have discovered that coal miners are characterized by a significant increase in the frequency of binucleated lymphocytes with micronuclei (MN), nucleoplasmic bridges (NPBs) and protrusions (NBUDs) compared to non-exposed donors. In addition, we report, for the first time, a reduction of cell proliferation in a cohort of coal miners. These data are evidence of the genotoxic and cytostatic effects of occupational harmful factors of the coal mining industry. No correlation between the level of chromosome damage and age, smoking status or length of service in coal mining conditions were discovered. We suggest that the CBMN assay would be useful in biomonitoring studies to monitor hygiene and prevention strategies in occupational settings in coal mining countries. © The Author 2016. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail:

  11. Cytotoxicity and Antiproliferative Activity Assay of Clove Mistletoe (Dendrophthoe pentandra (L. Miq. Leaves Extracts

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    Vida Elsyana


    Full Text Available Clove mistletoe (Dendrophthoe pentandra (L. Miq. is a semiparasitic plant that belongs to Loranthaceae family. Clove mistletoe was traditionally used for cancer treatment in Indonesia. In the present study, we examined cytotoxicity of clove mistletoe leaves extracts against brine shrimps and conducted their antiproliferative activity on K562 (human chronic myelogenous leukemia and MCM-B2 (canine benign mixed mammary cancer cell lines in vitro. The tested samples were water extract, ethanol extract, ethanol fraction, ethyl acetate fraction, and n-hexane fraction. Cytotoxicity was screened using Brine Shrimp Lethality Test (BSLT. Antiproliferative activity was conducted using Trypan Blue Dye Method and cells were counted using haemocytometer. The results showed that n-hexane fraction exhibited significant cytotoxicity with LC50 value of 55.31 μg/mL. The n-hexane fraction was then considered for further examination. The n-hexane fraction of clove mistletoe could inhibit growth of K562 and MCM-B2 cancer cell lines in vitro. The inhibition activity of clove mistletoe n-hexane fraction at concentration of 125 μg/mL on K562 cancer cell lines was 38.69%, while on MCM-B2 it was 41.5%. Therefore, it was suggested that clove mistletoe had potential natural anticancer activity.

  12. Mouse Embryonic Stem Cell Adherent Cell Differentiation and Cytotoxicity (ACDC) assay (United States)

    The Embryonic Stem Cell Test (EST) is an assay which evaluates xenobiotic-induced effects using three endpoints: mouse embryonic stem cell (mESC) differentiation, mESC viability, and 3T3-cell viability. Our research goal was to develop an improved high-throughput assay by establi...

  13. Cytotoxicity screening of 23 engineered nanomaterials using a test matrix of ten cell lines and three different assays

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    Göbbert Christian


    Full Text Available Abstract Background Engineered nanomaterials display unique properties that may have impact on human health, and thus require a reliable evaluation of their potential toxicity. Here, we performed a standardized in vitro screening of 23 engineered nanomaterials. We thoroughly characterized the physicochemical properties of the nanomaterials and adapted three classical in vitro toxicity assays to eliminate nanomaterial interference. Nanomaterial toxicity was assessed in ten representative cell lines. Results Six nanomaterials induced oxidative cell stress while only a single nanomaterial reduced cellular metabolic activity and none of the particles affected cell viability. Results from heterogeneous and chemically identical particles suggested that surface chemistry, surface coating and chemical composition are likely determinants of nanomaterial toxicity. Individual cell lines differed significantly in their response, dependent on the particle type and the toxicity endpoint measured. Conclusion In vitro toxicity of the analyzed engineered nanomaterials cannot be attributed to a defined physicochemical property. Therefore, the accurate identification of nanomaterial cytotoxicity requires a matrix based on a set of sensitive cell lines and in vitro assays measuring different cytotoxicity endpoints.

  14. Cytotoxicity test of 40, 50 and 60% citric acid as dentin conditioner by using MTT assay on culture cell line

    Directory of Open Access Journals (Sweden)

    Christian Khoswanto


    Full Text Available Background: Open dentin is always covered by smear layer, therefore before restoration is performed, cavity or tooth which has been prepared should be clean from dirt. The researchers suggested that clean dentin surface would reach effective adhesion between resin and tooth structure, therefore dentin conditioner like citric acid was used to reach the condition. Even though citric acid is not strong acid but it can be very erosive to oral mucous. Several requirements should be fulfilled for dental product such as non toxic, non irritant, biocompatible and should not have negative effect against local, systemic or biological environment. Cytotoxicity test was apart of biomaterial evaluation and needed for standard screening. Purpose: This study was to know the cytotoxicity of 40, 50, 60% citric acid as dentin conditioner using MTT assay. Method: This study is an experimental research using the Post-Test Only Control Group Design. Six samples of each 40, 50 and 60% citric acid for citotoxicity test using MTT assay. The density of optic formazan indicated the number of living cells. All data were statistically analyzed by one way ANOVA. Result: The percentage of living cells in 40, 50 and 60% citric acid were 95.14%, 93.42% and 93.14%. Conclusion: Citric acid is non toxic and safe to be used as dentine conditioner.

  15. High-throughput in vitro assay to evaluate the cytotoxicity of liberated platinum compounds for stimulating neural electrodes. (United States)

    Kovach, Kyle M; Kumsa, Doe W; Srivastava, Vishnupriya; Hudak, Eric M; Untereker, Darrel F; Kelley, Shawn C; von Recum, Horst A; Capadona, Jeffrey R


    It is currently unclear how the platinum (Pt) species released from platinum-containing stimulating electrodes may affect the health of the surrounding tissue. This study develops an effective system to assess the cytotoxicity of any electrode-liberated Pt over a short duration, to screen systems before future in vivo testing. A platinum electrode was stimulated for two hours under physiologically relevant conditions to induce the liberation of Pt species. The total concentration of liberated Pt species was quantified and the concentration found was used to develop a range of Pt species for our model system comprised of microglia and neuron-like cells. Under our stimulation conditions (k=2.3, charge density of 57.7μC/cm(2)), Pt was liberated to a concentration of 1ppm. Interestingly, after 24h of Pt exposure, the dose-dependent cytotoxicity plots revealed that cell death became statistically significant at 10ppm for microglia and 20ppm for neuronal cells. However, in neuron-like cell cultures, concentrations above 1ppm resulted in significant neurite loss after 24h. To our knowledge, there does not exist a simple, in vitro assay system for assessing the cytotoxicity of Pt liberated from stimulating neural electrodes. This work describes a simple model assay that is designed to be applicable to almost any electrode and stimulation system where the electrode is directly juxtaposed to the neural target. Based on the application, the duration of stimulation and Pt exposure may be varied. Published by Elsevier B.V.

  16. Cytotoxic assay of endophytic fungus 1.2.11 secondary metabolites from Brucea javanica (L Merr towards cancer cell in vitro

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    Pratiwi Sudarmono


    Full Text Available Cytotoxic assay of secondary metabolite endophytic fungus 1.2.11 from Brucea javanica (L Merr has been carried out. Brucea javanica fruit collected from Cianjur was used in this experiment. Cytotoxic assay was done on Raji, NS-1, HeLa and Vero cells. The observation was done for 24 hours and also for 48 hours. IC50 was calculated using the Rich and Muench theory. To observe the working mechanism of cytotoxic process, DNA staining with etidium bromide and acridine orange was conducted. The cytotoxic assay of endophytic fungi 1.2.11 showed an IC50 of 58.35 μg/ml, 88.39 μg/ml on Raji cell,; 162.09 μg/ml, 66.24 μg/ml on NS cell; 361.21 μg/ml, 219.97 μg/ml on HeLa cell; and lastly 1075.18 μg/ml, 656.82 μg/ml on Vero cell after 24 and 48 hour incubation respectively. The results of this study showed that secondary metabolite of endophytic fungus 1.2.11 has selective cytotoxic effect towards cancer cell and also showed that it might cause apoptosis in NS-1cell. (Med J Indones 2006; 15:137-44 Keywords: Brucea javanica (L. Merr, endophytic microbe, Cytotoxic assay, endophytic isolate 1.2.11, apoptosis

  17. Automation of an in vitro cytotoxicity assay used to estimate starting doses in acute oral systemic toxicity tests. (United States)

    Bouhifd, Mounir; Bories, Gilles; Casado, Juan; Coecke, Sandra; Norlén, Hedvig; Parissis, Nicholaos; Rodrigues, Robim M; Whelan, Maurice P


    Application of High Throughput Screening (HTS) to the regulatory safety assessment of chemicals is still in its infancy but shows great promise in terms of facilitating better understanding of toxicological modes-of-action, reducing the reliance on animal testing, and allowing more data-poor chemicals to be assessed at a reasonable cost. To promote the uptake and acceptance of HTS approaches, we describe in a stepwise manner how a well known cytotoxicity assay can be automated to increase throughput while maintaining reliability. Results generated with selected reference chemicals compared very favourably with data obtained from a previous international validation study concerning the prediction of acute systemic toxicity in rodents. The automated assay was then included in a formal ECVAM validation study to determine if the assay could be used for binary classification of chemicals with respect to their acute oral toxicity, using a threshold equivalent to a dose of 2000 mg/kg b.w. in a rodent bioassay (LD50). This involved the blind-testing of 56 reference chemicals on the HTS platform to produce concentration-response and IC50 data. Finally, the assay was adapted to a format more suited to higher throughput testing without compromising the quality of the data obtained. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Impact of assay selection and study design on the outcome of cytotoxicity testing of medical devices: the case of multi-purpose vision care solutions. (United States)

    Lehmann, David M; Richardson, Mary E


    Medical device biocompatibility testing usually includes a cytotoxicity component. Assay selection and protocol design often depend on a specific testing standard rather than on the characteristics of the medical device. To better understand the impact of assay selection on study outcome of unstructured medical devices, we evaluated contact lens multi-purpose solutions (MPS) in the agar diffusion, direct contact and two elution cytotoxicity assays. To simulate the conditions of use, MPS were evaluated alone and in combination with contact lenses. All MPS passed the agar diffusion assay (n=3) and extracts prepared from contact lenses soaked in MPS passed the USP elution assay (n=3). Both the duration of contact and MPS concentration impacted the outcome of a modified elution assay. When tested at 25% strength for 48 h, all MPS evaluated were non-cytotoxic (n>3). Test article movement and mechanical damage were significant issues with the direct contact assay. Movement was effectively controlled by manipulating contact lens orientation while using 0.8 mL culture medium. All MPS passed the USP direct contact cytotoxicity test when evaluated using this optimized methodology (n=3). These data are consistent with MPS results in ocular irritation studies in rabbits (n=3).

  19. Enhanced cytotoxicity and decreased CD8 dependence of human cancer-specific cytotoxic T lymphocytes after vaccination with low peptide dose. (United States)

    Lövgren, Tanja; Baumgaertner, Petra; Wieckowski, Sébastien; Devêvre, Estelle; Guillaume, Philippe; Luescher, Immanuel; Rufer, Nathalie; Speiser, Daniel E


    In mice, vaccination with high peptide doses generates higher frequencies of specific CD8+ T cells, but with lower avidity compared to vaccination with lower peptide doses. To investigate the impact of peptide dose on CD8+ T cell responses in humans, melanoma patients were vaccinated with 0.1 or 0.5 mg Melan-A/MART-1 peptide, mixed with CpG 7909 and Incomplete Freund's adjuvant. Neither the kinetics nor the amplitude of the Melan-A-specific CD8+ T cell responses differed between the two vaccination groups. Also, CD8+ T cell differentiation and cytokine production ex vivo were similar in the two groups. Interestingly, after low peptide dose vaccination, Melan-A-specific CD8+ T cells showed enhanced degranulation upon peptide stimulation, as assessed by CD107a upregulation and perforin release ex vivo. In accordance, CD8+ T cell clones derived from low peptide dose-vaccinated patients showed significantly increased degranulation and stronger cytotoxicity. In parallel, Melan-A-specific CD8+ T cells and clones from low peptide dose-vaccinated patients expressed lower CD8 levels, despite similar or even stronger binding to tetramers. Furthermore, CD8+ T cell clones from low peptide dose-vaccinated patients bound CD8 binding-deficient tetramers more efficiently, suggesting that they may express higher affinity TCRs. We conclude that low peptide dose vaccination generated CD8+ T cell responses with stronger cytotoxicity and lower CD8 dependence.

  20. Proliferative activity, lectin-dependent and natural cytotoxicity in blood, lymph node and spleen from patients with Hodgkin's disease. (United States)

    Bykovskaya, S N; Blochina, N G; Charabadze, M V; Agaphonov, V A; Kupriyanova, T A


    Mononuclear cells and T-lymphocytes of the blood, spleen and lymph nodes from 48 patients with Hodgkin disease (HD) and blood donors were tested in assays for lectin-dependent (LD) and natural killer (NK) cytotoxic activity. On average, peripheral blood T cell lectin-dependent cytotoxicity differs from that of the donors. However, cytotoxic activity appears to be dependent on the stage of disease; in the IY stage LD cytotoxicity was decreased 2-fold. The lectin-dependent cytotoxicity was also dependent on the histological type of disease and the lowest level (50% of the control level) was associated with the lymphoid depletion type. The cytotoxic activity of T-lymphocytes from the affected areas of the patients' spleen was more marked than that of the unaffected areas. Spleen cell cytotoxicity showed no other correlations. Cytotoxicity of lymphocytes from the affected lymph nodes was drastically lower than activity of blood and spleen lymphocytes. NK activity of the patients' blood and spleen lymphocytes was twice as low as the control level (healthy donors) and did not correlate with stage and/or histological type of disease. The proliferative activity of lymphocytes from 33 HD patients was tested in vitro using allogeneic mononuclear cells from healthy donors or HD patients and/or PHA as stimulators. The response of patients' lymphocytes to alloantigens appeared to be much less affected than response to polyclonal mitogen. Thus, the results obtained by us demonstrate signs of stimulation of the lymphoid system against a background of general immunosuppression in HD.

  1. No association of the cytotoxic T-lymphocyte associated gene CTLA4 +49A/G polymorphisms with Crohn's disease and ulcerative colitis in Hungarian population samples

    Institute of Scientific and Technical Information of China (English)

    Lili Magyari; Béla Melegh; Bernadett Faragó; Judit Bene; Katalin Horvatovich; Lilla Lakner; Márta Varga; Mária Figler; Beáta Gasztonyi; Gyula Mózsik


    AIM: The goal of the current work was to analyse the prevalence of the +49A/G variant of the cytotoxic T-lymphocyte antigen 4 gene (CTLA4) in Hungarian patients with Crohn's disease (CD) and ulcerative colitis (UC).METHODS: A total of 130 unrelated subjects with CD and 150 with UC, and 170 matched controls were genotyped for the single nucleotide polymorphism (SNP).The genotypes were determined by using PCR/RFLP test.RESULTS: The G allele frequency and the prevalence of the GG genotype were 38.1% and 12.3% in the CD group, 40.6% and 18.6% in the UC patients, and 37.4%and 15.9% in the control group, respectively.CONCLUSION: The results of the current study show that carriage of the +49G SNP in heterozygous or in homozygous form does not confer risk either for CD or for UC in the Hungarian population.

  2. Suppressor T cells, distinct from "veto cells," are induced by alloantigen priming and mediate transferable suppression of cytotoxic T lymphocyte responses in vivo

    DEFF Research Database (Denmark)

    Owens, T; Crispe, I N


    Primary and secondary cytotoxic T lymphocyte responses to minor alloantigens can be suppressed by priming host mice with a high dose (10(8) cells) of alloantigenic donor spleen cells (SC). Such suppression is antigen specific and transferable into secondary hosts with T cells. One interpretation...... of this is that antigen-specific host suppressor T cells (Ts) are activated. Alternatively, donor Lyt-2+ T cells, introduced in the priming inoculum, may inactivate host CTL precursors (CTLp) that recognize the priming (donor) alloantigens. Donor cells that act in this way are termed veto T cells. The experiments...... for the transfer of suppression of a secondary CTL response to B10 minors was of the host Thy-1 allotype, and so originated in the host spleen and was not introduced in the priming inoculum. Secondly, antigen-specific Ts generated in CBA female mice against B10 minors could act on CTL responses to an unequivocally...

  3. The susceptibility to cytotoxic T lymphocyte mediated lysis of chemically induced sarcomas from immunodeficient and normal mice

    DEFF Research Database (Denmark)

    Svane, I M; Engel, A M; Thomsen, Allan Randrup


    tested for susceptibility to cytolysis by virus specific cytotoxic T cells. Tumour cells originating from tumours induced in immunocompetent C.B.-17 mice presented virus antigen more efficiently than tumour cells from immunodeficient SCID mice. No significant difference in virus antigen presentation...

  4. Investigation on the mechanisms of genotoxicity of butadiene, styrene and their combination in human lymphocytes using the Comet assay. (United States)

    Cemeli, Eduardo; Mirkova, Ekaterina; Chiuchiarelli, Giorgia; Alexandrova, Elena; Anderson, Diana


    The toxicity of butadiene and styrene is exerted by their metabolites. Such metabolites have been extensively scrutinized at the in vitro level demonstrating evident genotoxic properties. In monitoring, a diverse range of outcomes has been produced. Additionally, epidemiological studies in rubber workers face difficulties of data interpretation due to the changeability and multiple exposures of the workers as well as to confounding factors inherent to the cohorts. Nevertheless, toxicity has been associated with a significant trend of increasing the risk of leukaemia in employees at the styrene-butadiene rubber industry. Thus, further effort must be made to distinguish the exposures to each chemical over time and to characterize their interrelationships. The present investigation focuses on the effects and mechanisms of damage of the mixture styrene-butadiene by examining its metabolites: styrene oxide (SO), butadiene monoepoxide (BME) and butadiene diepoxide (BDE) respectively. The in vitro Comet assay on frozen lymphocytes has been employed to ascertain the DNA damage patterns for the styrene-butadiene metabolites combined and on their own. Different patterns were observed for the mixture and each of its components. This study has also led to determining the mechanism of damage of the mixture and the compounds. With regard to the presence of reactive oxygen species (ROS), co-treatment with catalase does not modulate the genotoxicity of the mixture but it does modulate its components. The outcomes also indicate that the mixture induces cross-links and this is due to the influence of BDE in the mixture, being more evident as the concentration of BDE increases. An investigation on the sensitivity of lymphocytes from occupationally un/exposed subjects to in vitro exposure of the mixture and its components revealed that occupationally exposed subjects had a substantially higher background of DNA damage and a lower sensitivity to the metabolites of styrene, 1

  5. Interleukin-2 activation of cytotoxic cells in postmastectomy seroma. (United States)

    Gercel-Taylor, C; Hoffman, J P; Taylor, D D; Owens, K J; Eisenberg, B L


    Lymphocytes were isolated from breast seroma fluids and used to study the mechanism of activation of cytotoxic lymphocytes and possible role of immunological potentiation following surgery in breast cancer patients. Single or serial samples were obtained from patients who had undergone mastectomy or lumpectomy with axillary node dissection. Lymphocytes were activated with rIL-2 (interleukin-2) and their cytotoxic activity was studied against Daudi and K562 cells and against a breast tumor line (SKBr-3). All of the patients (21/21) responded to IL-2 stimulation by significant activation of cytotoxic activity. The unstimulated cytotoxic activity of these cells against NK targets was low with less than 10% specific release in cytotoxicity assays. In simultaneous experiments, autologous seroma fluid was included during activation of lymphocytes to study possible regulatory molecules that may be present. In 17/21 patients, the presence of their seroma fluid, during the activation period, enhanced or did not effect the cytotoxic potential of their lymphocytes; inhibition was observed when seroma fluids from 4/21 patients were included. Analysis of the cytotoxic population derived from combined IL-2 and seroma treatments indicates the presence of cells with increased expression of CD56, and CD2, as well as in some cases CD16 expression. Cytotoxic lymphocytes derived from IL-2 and seroma treatments appeared to be more effective killers. Modulation of CD2 expression with seroma alone appeared to result in the generation of this highly cytotoxic population. This study demonstrates the role of CD2 expression in the effectiveness of LAK cell killing and also potential benefit of an immunotherapeutic approach to the postoperative treatment of carcinoma of the breast.

  6. Optimal dose selection of N-methyl-N-nitrosourea for the rat comet assay to evaluate DNA damage in organs with different susceptibility to cytotoxicity. (United States)

    Kitamoto, Sachiko; Matsuyama, Ryoko; Uematsu, Yasuaki; Ogata, Keiko; Ota, Mika; Yamada, Toru; Miyata, Kaori; Funabashi, Hitoshi; Saito, Koichi


    The in vivo rodent alkaline comet assay (comet assay) is a promising technique to evaluate DNA damage in vivo. However, there is no agreement on a method to evaluate DNA damage in organs where cytotoxicity is observed. As a part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative international validation study of the comet assay, we examined DNA damage in the liver, stomach, and bone marrow of rats given three oral doses of N-methyl-N-nitrosourea (MNU) up to the maximum tolerated dose based on systemic toxicity. MNU significantly increased the % tail DNA in all the organs. Histopathological analysis showed no cytotoxic effect on the liver, indicating clearly that MNU has a genotoxic potential in the liver. In the stomach, however, the cytotoxic effects were very severe at systemically non-toxic doses. Low-dose MNU significantly increased the % tail DNA even at a non-cytotoxic dose, indicating that MNU has a genotoxic potential also in the stomach. Part of the DNA damage at cytotoxic doses was considered to be a secondary effect of severe cell damage. In the bone marrow, both the % tail DNA and incidence of micronucleated polychromatic erythrocytes significantly increased at non-hematotoxic doses, which were different from the non-cytotoxic doses for liver and stomach. These findings indicate that an optimal dose for detecting DNA damage may vary among organs and that careful attention is required to select an optimum dose for the comet assay based on systemic toxicity such as mortality and clinical observations. The present study shows that when serious cytotoxicity is suggested by increased % hedgehogs in the comet assay, histopathological examination should be included for the evaluation of a positive response.

  7. Evaluation of 309 environmental chemicals using a mouse embryonic stem cell adherent cell differentiation and cytotoxicity assay.

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    Kelly J Chandler

    Full Text Available The vast landscape of environmental chemicals has motivated the need for alternative methods to traditional whole-animal bioassays in toxicity testing. Embryonic stem (ES cells provide an in vitro model of embryonic development and an alternative method for assessing developmental toxicity. Here, we evaluated 309 environmental chemicals, mostly food-use pesticides, from the ToxCast™ chemical library using a mouse ES cell platform. ES cells were cultured in the absence of pluripotency factors to promote spontaneous differentiation and in the presence of DMSO-solubilized chemicals at different concentrations to test the effects of exposure on differentiation and cytotoxicity. Cardiomyocyte differentiation (α,β myosin heavy chain; MYH6/MYH7 and cytotoxicity (DRAQ5™/Sapphire700™ were measured by In-Cell Western™ analysis. Half-maximal activity concentration (AC₅₀ values for differentiation and cytotoxicity endpoints were determined, with 18% of the chemical library showing significant activity on either endpoint. Mining these effects against the ToxCast Phase I assays (∼500 revealed significant associations for a subset of chemicals (26 that perturbed transcription-based activities and impaired ES cell differentiation. Increased transcriptional activity of several critical developmental genes including BMPR2, PAX6 and OCT1 were strongly associated with decreased ES cell differentiation. Multiple genes involved in reactive oxygen species signaling pathways (NRF2, ABCG2, GSTA2, HIF1A were strongly associated with decreased ES cell differentiation as well. A multivariate model built from these data revealed alterations in ABCG2 transporter was a strong predictor of impaired ES cell differentiation. Taken together, these results provide an initial characterization of metabolic and regulatory pathways by which some environmental chemicals may act to disrupt ES cell growth and differentiation.

  8. In vitro cytotoxicity of four calcium silicate-based endodontic cements on human monocytes, a colorimetric MTT assay

    Directory of Open Access Journals (Sweden)

    Sedigheh Khedmat


    Full Text Available Objectives This study was performed to evaluate the cytotoxicity of four calcium silicate-based endodontic cements at different storage times after mixing. Materials and Methods Capillary tubes were filled with Biodentine (Septodont, Calcium Enriched Mixture (CEM cement, BioniqueDent, Tech Biosealer Endo (Tech Biosealer and ProRoot MTA (Dentsply Tulsa Dental. Empty tubes and tubes containing Dycal were used as negative and positive control groups respectively. Filled capillary tubes were kept in 0.2 mL microtubes and incubated at 37℃. Each material was divided into 3 groups for testing at intervals of 24 hr, 7 day and 28 day after mixing. Human monocytes were isolated from peripheral blood mononuclear cells and cocultered with 24 hr, 7 day and 28 day samples of different materials for 24 and 48 hr. Cell viability was evaluated using an MTT assay. Results In all groups, the viability of monocytes significantly improved with increasing storage time regardless of the incubation time (p < 0.001. After 24 hr of incubation, there was no significant difference between the materials regarding monocyte viability. However, at 48 hr of incubation, ProRoot MTA and Biodentine were less cytotoxic than CEM cement and Biosealer (p < 0.01. Conclusions Biodentine and ProRoot MTA had similar biocompatibility. Mixing ProRoot MTA with PBS in place of distilled water had no effect on its biocompatibility. Biosealer and CEM cement after 48 hr of incubation were significantly more cytotoxic to on monocyte cells compared to ProRoot MTA and Biodentine.

  9. Single-colour flow cytometric assay to determine NK cell-mediated cytotoxicity and viability against non-adherent human tumor cells. (United States)

    Thakur, Ajit; Zaman, Abeyat; Hummel, Jeff; Jones, Kim; Hortelano, Gonzalo


    A flow cytometry-based cytotoxicity (FCC) assay was developed using a single fluorophore, calcein-acetoxymethyl diacetylester (calcein-AM), to measure NK cell-mediated cytotoxicity. Non-adherent human K562 and U937 target cells were individually labelled with calcein-AM and co-incubated with effector NK cells to measure calcein loss, and therefore calculate target cell cytotoxicity. This FCC assay also provided a measure of sample viability. Notably, cell viability measured by traditional calcein/7-amino-actinomycin D (7-AAD) double labelling and Trypan Blue methods were comparable to the viability calculated using calcein-loss FCC. This FCC assay may also be used with various effector and target cell types and as a multi-parameter tool to measure viability and immunophenotype cells for tissue engineering purposes.

  10. The prognostic value of cytotoxic T-lymphocyte antigen 4 in cancers: a systematic review and meta-analysis (United States)

    Hu, Pingping; Liu, Qiqi; Deng, Guodong; Zhang, Jingxin; Liang, Ning; Xie, Jian; Zhang, Jiandong


    The outcomes of studies analyzing the prognostic role of CTLA-4 in cancers are controversial. Therefore, the aim of our meta-analysis was to clarify the correlation between CTLA-4 expression and OS in different cancer cases. Relevant literature was searched using PubMed, EMBASE, Web of Science, and the Cochrane Library. The clinicopathological features, hazard ratio (HR) and 95% confidence intervals (CI) were collected from these studies and were analyzed using Stata version 12.0 software. The pooled HR values showed no significant correlation between CTLA-4 expression levels and OS in relation to tumors (HR: 1.24, 95% CI: 0.98–1.56, I2 = 71.7%, P = 0.000). Further subgroup analyses were conducted and categorized by experimental methods, CTLA-4 sources and cancer types. The survey showed a significant correlation (HR: 1.47, 95% CI: 1.14–1.89) between high expression of CTLA-4 and OS in the SNP subgroup, and subgroups analyzing by PCR (HR: 1.50, 95% CI: 1.20–1.86) and flow cytometry (HR: 2.76, 95% CI: 1.49–5.14). In addition, our analysis observed significant differences between patients and controls in inCTLA-4+CD4+ lymphocytes, surCTLA-4+CD4+ lymphocytes, inCTLA-4+CD8+ lymphocytes, and surCTLA-4+CD8+ lymphocytes. Knowledge of the effects of CTLA-4 could potentially be used to effectively guide appropriate prognosis and therapeutic strategies in cancer patients. PMID:28211499

  11. Efficient lysis of epithelial ovarian cancer cells by MAGE-A3-induced cytotoxic T lymphocytes using rAAV-6 capsid mutant vector. (United States)

    Batchu, Ramesh B; Gruzdyn, Oksana V; Moreno-Bost, Amberly M; Szmania, Susann; Jayandharan, Giridhararao; Srivastava, Arun; Kolli, Bala K; Weaver, Donald W; van Rhee, Frits; Gruber, Scott A


    MAGE-A3 is highly expressed in epithelial ovarian cancer (EOC), making it a promising candidate for immunotherapy. We investigated whether dendritic cells (DCs) transduced with a rAAV-6 capsid mutant vector Y445F could elicit effective MAGE-A3-specific anti-tumor cytotoxic T lymphocyte (CTL) responses in vitro. MAGE-A3 was cloned and rAAV-6-MAGE-A3 purified, followed by proviral genome detection using real-time PCR. Immunofluorescence detection of rAAV-6-Y445F-MAGE-A3-transduced DCs demonstrated 60% transduction efficiency. Fluorescent in situ hybridization analysis confirmed chromosomal integration of rAAV vectors. Flow cytometric analysis of transduced DCs showed unaltered expression of critical monocyte-derived surface molecules with retention of allo-stimulatory activity. Co-culture of autologous T lymphocytes with MAGE-A3-expressing DCs produced CTLs that secreted IFN-γ, and efficiently killed MAGE-A3+ EOC cells. This form of rAAV-based DC immunotherapy, either alone or more likely in combination with other immune-enhancing protocols, may prove useful in the clinical setting for management of EOC.

  12. The noncellular reduction of MTT tetrazolium salt by TiO₂ nanoparticles and its implications for cytotoxicity assays. (United States)

    Lupu, A R; Popescu, T


    We report results of noncellular tests, revealing the occurrence of photocatalytic interactions between titanium dioxide (TiO2, titania) nanoparticles and the MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide] cytotoxicity indicator. These interactions induce the reduction of MTT and formation of purple formazan under biologically relevant conditions. Classical MTT assays have been performed to evaluate the production of formazan in DMEM-F12 and RPMI-1640 cell culture media (containing 10% fetal bovine serum-FBS) treated with Degussa-P25 TiO2 nanoparticles, in the absence of cells. The colorimetric determinations revealed the noncellular MTT to formazan transformation induced by TiO2 nanoparticles, under conditions commonly used for in vitro cytotoxicity testing of nanomaterials. The formazan precipitation was found to be proportional to the TiO2 concentration, being enhanced under laboratory daylight exposure. The photocatalytic nature of the studied effect was assessed under UV irradiation at 365nm. The biological significance of the reported reaction was established with respect to cellular reference experiments performed on V79-4, HeLa and B16 cell lines. The results show false viability increases with up to 14% (for TiO2 concentrations generally higher than 50μg/ml), induced by the TiO2-MTT reaction. This type of artifacts may lead to underestimated toxicity or false proliferation results.

  13. Malignant monoblasts can function as effector cells in natural killer cell and antibody-dependent cellular cytotoxicity assays

    DEFF Research Database (Denmark)

    Hokland, P; Hokland, M; Ellegaard, J


    This is the first report describing natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC) of malignant monoblasts. Pure acute monoblastic leukemia was diagnosed in bone marrow aspirations from two patients by use of conventional cytochemical methods as well as multiple immunologic...... techniques including detection of ALL antigens and terminal transferase. The malignant cells were subsequently found to be potent effectors in NK and ADCC assays. Addition of partially purified alpha-interferon to the in vitro cultures was found to have an enhancing effect on NK activity, whereas...... no modulation was seen in ADCC. These findings are discussed in the light of our present knowledge of lymphoid NK cells. Udgivelsesdato: 1981-May...

  14. In-vitro assessment of cytotoxicity of halloysite nanotubes against HepG2, HCT116 and human peripheral blood lymphocytes. (United States)

    Ahmed, Farrukh Rafiq; Shoaib, Muhammad Harris; Azhar, Mudassar; Um, Soong Ho; Yousuf, Rabia Ismail; Hashmi, Shahkamal; Dar, Ahsana


    Halloysite is a clay mineral with chemical similarity to kaolin, a pharmaceutical ingredient. It consists of mainly aluminosilicate nanotubular particles in the size range of ∼ 200-1000 nm. Many studies have tried to empirically explore this novel clay for its potential in drug delivery systems but no work has yet studied its cytotoxicity from the perspective of oral drug delivery system. In this study, the halloysite nanotubes (HNTs) were subjected to size distribution analyses, which reveal more than 50% of nanotubes in the size range of 500 nm and rest mainly in the sub micrometer range. HNTs were then evaluated for in-vitro cytotoxicity against HCT116 (colorectal carcinoma) and HepG2 (hepatocellular carcinoma) cells which represent the earliest entry point and the first accumulating organ, respectively, for nanoparticles en-route to systemic circulation after oral delivery. Moreover, HNTs were tested for their cytogenetic toxicity against human peripheral blood lymphocytes. Both these results collectively indicated that HNTs are generally safe at practical concentrations of excipients for oral dosage forms.

  15. Caspase activation as a versatile assay platform for detection of cytotoxic bacterial toxins. (United States)

    Payne, Angela M; Zorman, Julie; Horton, Melanie; Dubey, Sheri; ter Meulen, Jan; Vora, Kalpit A


    Pathogenic bacteria produce several virulence factors that help them establish infection in permissive hosts. Bacterial toxins are a major class of virulence factors and hence are attractive therapeutic targets for vaccine development. Here, we describe the development of a rapid, sensitive, and high-throughput assay that can be used as a versatile platform to measure the activities of bacterial toxins. We have exploited the ability of these toxins to cause cell death via apoptosis of sensitive cultured cell lines as a readout for measuring toxin activity. Caspases (cysteine-aspartic proteases) are induced early in the apoptotic pathway, and so we used their induction to measure the activities of Clostridium difficile toxins A (TcdA) and B (TcdB) and binary toxin (CDTa-CDTb), Corynebacterium diphtheriae toxin (DT), and Pseudomonas aeruginosa exotoxin A (PEA). Caspase induction in the cell lines, upon exposure to toxins, was optimized by toxin concentration and intoxication time, and the specificity of caspase activity was established using a genetically mutated toxin and a pan-caspase inhibitor. In addition, we demonstrate the utility of the caspase assay for measuring toxin potency, as well as neutralizing antibody (NAb) activity against C. difficile toxins. Furthermore, the caspase assay showed excellent correlation with the filamentous actin (F-actin) polymerization assay for measuring TcdA and TcdB neutralization titers upon vaccination of hamsters. These results demonstrate that the detection of caspase induction due to toxin exposure using a chemiluminescence readout can support potency and clinical immunogenicity testing for bacterial toxin vaccine candidates in development.

  16. Novel immunodominant peptide presentation strategy: a featured HLA-A*2402-restricted cytotoxic T-lymphocyte epitope stabilized by intrachain hydrogen bonds from severe acute respiratory syndrome coronavirus nucleocapsid protein. (United States)

    Liu, Jun; Wu, Peng; Gao, Feng; Qi, Jianxun; Kawana-Tachikawa, Ai; Xie, Jing; Vavricka, Christopher J; Iwamoto, Aikichi; Li, Taisheng; Gao, George F


    Antigenic peptides recognized by virus-specific cytotoxic T lymphocytes (CTLs) are presented by major histocompatibility complex (MHC; or human leukocyte antigen [HLA] in humans) molecules, and the peptide selection and presentation strategy of the host has been studied to guide our understanding of cellular immunity and vaccine development. Here, a severe acute respiratory syndrome coronavirus (SARS-CoV) nucleocapsid (N) protein-derived CTL epitope, N1 (QFKDNVILL), restricted by HLA-A*2402 was identified by a series of in vitro studies, including a computer-assisted algorithm for prediction, stabilization of the peptide by co-refolding with HLA-A*2402 heavy chain and β(2)-microglobulin (β(2)m), and T2-A24 cell binding. Consequently, the antigenicity of the peptide was confirmed by enzyme-linked immunospot (ELISPOT), proliferation assays, and HLA-peptide complex tetramer staining using peripheral blood mononuclear cells (PBMCs) from donors who had recovered from SARS donors. Furthermore, the crystal structure of HLA-A*2402 complexed with peptide N1 was determined, and the featured peptide was characterized with two unexpected intrachain hydrogen bonds which augment the central residues to bulge out of the binding groove. This may contribute to the T-cell receptor (TCR) interaction, showing a host immunodominant peptide presentation strategy. Meanwhile, a rapid and efficient strategy is presented for the determination of naturally presented CTL epitopes in the context of given HLA alleles of interest from long immunogenic overlapping peptides.

  17. Synthesis, characterization and preliminary cytotoxicity assays of poly(ethylene glycol)-malonato-Pt-DACH conjugates. (United States)

    Furin, Alessia; Guiotto, Andrea; Baccichetti, Franca; Pasut, Gianfranco; Deuschel, Christine; Bertani, Roberta; Veronese, Francesco M


    Oxalate 1,2-diaminocyclohexane platinum (oxaliplatin(R)), a successfully employed platinum compound belonging to the family of Pt-DACH complexes, has been conjugated to different molecular weight poly(ethylene glycols) (PEG) by means of peptide spacers and a malonic acid bidentate residue. Tri- and tetrapeptidic substrates of lysosomal enzymes were used in order to increase the release of Pt-DACH complex inside the cell following endocytosis and enzymatic degradation of the peptide spacer. Other aminoacids (e.g. norleucine) have been also employed. 1H-NMR of some conjugates was performed as characterisation of the product, while 195Pt-NMR analysis was carried out to detect the rearrangement of the platinum complex from the Pt(O,O) to the Pt(O,N) form. The compound PEG(5000)-Nle-malonato-Pt-DACH (4) has been tested against L1210-implanted mice and showed and appreciable increase in cytotoxicity as compared to the reference standard Cl(2)PtDACH.

  18. A simple protocol for using a LDH-based cytotoxicity assay to assess the effects of death and growth inhibition at the same time.

    Directory of Open Access Journals (Sweden)

    Shilo M Smith

    Full Text Available Analyzing the effects on cell growth inhibition and/or cell death has been an important component of biological research. The MTS assay and LDH-based cytotoxicity assays are two of the most commonly used methods for this purpose. However, data here showed that MTS cell proliferation assay could not distinguish the effects of cell death or cell growth inhibition. In addition, the original LDH-based cytotoxicity protocol grossly underestimated the proportion of dead cells in conditions with growth inhibition. To overcome the limitation, we present here a simple modified LDH-based cytotoxicity protocol by adding additional condition-specific controls. This modified protocol thus can provide more accurate measurement of killing effects in addition to the measurement of overall effects, especially in conditions with growth inhibition. In summary, we present here a simple, modified cytotoxicity assay, which can determine the overall effects, percentage of cell killing and growth inhibition in one 96-well based assay. This is a viable option for primary screening for many laboratories, and could be adapted for high throughput screening.

  19. Simultaneous assessment of cytotoxic T lymphocyte responses against multiple viral infections by combined usage of optimal epitope matrices, anti- CD3 mAb T-cell expansion and "RecycleSpot"

    Directory of Open Access Journals (Sweden)

    Wong Johnson T


    Full Text Available Abstract The assessment of cellular anti-viral immunity is often hampered by the limited availability of adequate samples, especially when attempting simultaneous, high-resolution determination of T cell responses against multiple viral infections. Thus, the development of assay systems, which optimize cell usage, while still allowing for the detailed determination of breadth and magnitude of virus-specific cytotoxic T lymphocyte (CTL responses, is urgently needed. This study provides an up-to-date listing of currently known, well-defined viral CTL epitopes for HIV, EBV, CMV, HCV and HBV and describes an approach that overcomes some of the above limitations through the use of peptide matrices of optimally defined viral CTL epitopes in combination with anti-CD3 in vitro T cell expansion and re-use of cells from negative ELISpot wells. The data show that, when compared to direct ex vivo cell preparations, antigen-unspecific in vitro T cell expansion maintains the breadth of detectable T cell responses and demonstrates that harvesting cells from negative ELISpot wells for re-use in subsequent ELISpot assays (RecycleSpot, further maximized the use of available cells. Furthermore when combining T cell expansion and RecycleSpot with the use of rationally designed peptide matrices, antiviral immunity against more than 400 different CTL epitopes from five different viruses can be reproducibly assessed from samples of less than 10 milliliters of blood without compromising information on the breadth and magnitude of these responses. Together, these data support an approach that facilitates the assessment of cellular immunity against multiple viral co-infections in settings where sample availability is severely limited.

  20. Cytotoxic and genotoxic activity of some Helleborus species. (United States)

    Čakar, Jasmina; Haverić, Anja; Haverić, Sanin; Maksimović, Milka; Parić, Adisa


    Despite their known toxic properties, various Helleborus species are used as medicaments in folk medicine to treat some diseases and health conditions. As the main mechanism of many cytostatic drugs is based on their cytotoxic activity, there is potential for the toxicity of hellebore to be used in anticancer therapy. This study tested the geno- and cytotoxic effects of extracts of three hellebore taxa (Helleborus odorus, Helleborus multifidus and Helleborus hercegovinus) on meristemic onion (Alliumcepa L.) cells and human lymphocytes. Treatments with Helleborus extracts induced cytotoxic and cytostatic effects in meristemic onion cells as well as in cultivated cytokinesis-blocked human lymphocytes. Cytokinesis-block micronucleus cytome assay indicated that treatments with hellebore extracts induce genotoxic effects in human lymphocytes, and that the significant mechanism of their antiproliferative activity is apoptosis induction.

  1. Improving anticancer drug development begins with cell culture: misinformation perpetrated by the misuse of cytotoxicity assays. (United States)

    Eastman, Alan


    The high failure rate of anticancer drug discovery and development has consumed billions of dollars annually. While many explanations have been provided, I believe that misinformation arising from inappropriate cell-based screens has been completely over-looked. Most cell culture experiments are irrelevant to how drugs are subsequently administered to patients. Usually, drug development focuses on growth inhibition rather than cell killing. Drugs are selected based on continuous incubation of cells, then frequently administered to the patient as a bolus. Target identification and validation is often performed by gene suppression that inevitably mimics continuous target inhibition. Drug concentrations in vitro frequently far exceed in vivo concentrations. Studies of drug synergy are performed at sub-optimal concentrations. And the focus on a limited number of cell lines can misrepresent the potential efficacy in a patient population. The intent of this review is to encourage more appropriate experimental design and data interpretation, and to improve drug development in the area of cell-based assays. Application of these principles should greatly enhance the successful translation of novel drugs to the patient.

  2. Miniaturization of cytotoxicity tests for concentration range-finding studies prior to conducting the pH 6.7 Syrian hamster embryo cell-transformation assay. (United States)

    Plöttner, Sabine; Käfferlein, Heiko U; Brüning, Thomas


    The Syrian hamster embryo (SHE) cell-transformation assay (SHE assay) is a promising alternative method to animal testing for the identification of potential carcinogens in vitro. Prior to conducting the SHE assay the appropriate concentration range for each test chemical must be established, with a maximum concentration causing approximately 50% cytotoxicity. Concentration range-finding is done in separate experiments, which are similar to the final SHE assay but with less replicates and more concentrations. Here we present an alternative for the cytotoxicity testing by miniaturization of the test procedure by use of 24-well plates and surpluses from feeder-cell preparations as target cells. In addition, we integrated the photometry-based neutral red (NR) assay. For validation of the assay, incubations with dimethyl sulf-oxide, p-phenylenediamine-2HCl, aniline, o-toluidine-HCl, 2,4-diaminotoluene, and 2-naphthylamine were carried out in the miniaturized approach and compared with the standard procedure in terms of calculating the relative plating efficiencies (RPEs). To directly compare both methods, concentrations that produced 50% cytotoxicity (IC50) were calculated. Excellent associations were observed between the number of colonies and NR uptake. For all test substances a concentration-dependent, concomitant decrease of NR uptake in the miniaturized approach and RPEs in the standard test was observed after a 7-day incubation. The results from both test setups showed a comparable order of magnitude and the IC50 values differed by a factor cytotoxicity testing in the SHE assay, as it saves valuable SHE cells and speeds-up the time, to obtain test results more rapidly. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. JAK-STAT-mediated chronic inflammation impairs cytotoxic T lymphocyte activation to decrease anti-PD-1 immunotherapy efficacy in pancreatic cancer. (United States)

    Lu, Chunwan; Talukder, Asif; Savage, Natasha M; Singh, Nagendra; Liu, Kebin


    Human pancreatic cancer does not respond to immune check point blockade immunotherapy. One key feature of pancreatic cancer is the association between its progression and chronic inflammation. Emerging evidence supports a key role for the JAK-STAT pathway in pancreatic cancer inflammation. We aimed at testing the hypothesis that sustained JAK-STAT signaling suppresses cytotoxic T lymphocyte (CTL) activation to counteract anti-PD-1 immunotherapy-induced CTL activity in pancreatic cancer. We show that human pancreatic carcinomas express high level of PD-L1 and exhibit low level of CTL infiltration. JAK-STAT inhibitor Ruxolitinib selectively inhibits STAT1 and STAT3 activation and increases CTL infiltration to induce a Tc1/Th1 immune response in the tumor microenvironment in an orthotopic pancreatic cancer mouse model. Ruxilitinib-mediated tumor suppressive efficacy diminishes in T-cell-deficient mice. Pancreatic tumor grows significantly faster in IFNγ-deficient mice. However, neutralizing IFNγ does not alter tumor growth but diminishes Ruxolitinib-induced tumor suppression in vivo, indicating that lymphocytes and IFNγ are essential for Ruxolitinib-induced host antitumor immune response. Both type I and type II interferons upregulate PD-L1 expression through the JAK-STAT signaling pathway in mouse pancreatic tumor cells. Tumor cells respond to activated T cells by activating STAT3. The inhibition of STAT3 downregulates immune suppressive cytokines production by tumor cells, resulting in increased T cell activation and effector function. Consequently, Ruxolitinib significantly improves the efficacy of anti-PD-1 immunotherapy. Our data demonstrate that Ruxolitinib is effective in the inhibition of systemic inflammation in the tumor microenvironment and therefore upregulates CTL infiltration and activation to overcome pancreatic cancer resistance to anti-PD-1 immunotherapy.

  4. A new extract of the plant calendula officinalis produces a dual in vitro effect: cytotoxic anti-tumor activity and lymphocyte activation

    Directory of Open Access Journals (Sweden)

    Collado Antonia


    Full Text Available Abstract Background Phytopharmacological studies of different Calendula extracts have shown anti-inflamatory, anti-viral and anti-genotoxic properties of therapeutic interest. In this study, we evaluated the in vitro cytotoxic anti-tumor and immunomodulatory activities and in vivo anti-tumor effect of Laser Activated Calendula Extract (LACE, a novel extract of the plant Calendula Officinalis (Asteraceae. Methods An aqueous extract of Calendula Officinalis was obtained by a novel extraction method in order to measure its anti-tumor and immunomodulatory activities in vitro. Tumor cell lines derived from leukemias, melanomas, fibrosarcomas and cancers of breast, prostate, cervix, lung, pancreas and colorectal were used and tumor cell proliferation in vitro was measured by BrdU incorporation and viable cell count. Effect of LACE on human peripheral blood lymphocyte (PBL proliferation in vitro was also analyzed. Studies of cell cycle and apoptosis were performed in LACE-treated cells. In vivo anti-tumor activity was evaluated in nude mice bearing subcutaneously human Ando-2 melanoma cells. Results The LACE extract showed a potent in vitro inhibition of tumor cell proliferation when tested on a wide variety of human and murine tumor cell lines. The inhibition ranged from 70 to 100%. Mechanisms of inhibition were identified as cell cycle arrest in G0/G1 phase and Caspase-3-induced apoptosis. Interestingly, the same extract showed an opposite effect when tested on PBLs and NKL cell line, in which in vitro induction of proliferation and activation of these cells was observed. The intraperitoneal injection or oral administration of LACE extract in nude mice inhibits in vivo tumor growth of Ando-2 melanoma cells and prolongs the survival day of the mice. Conclusion These results indicate that LACE aqueous extract has two complementary activities in vitro with potential anti-tumor therapeutic effect: cytotoxic tumor cell activity and lymphocyte activation

  5. Identification of two epitopes on the dengue 4 virus capsid protein recognized by a serotype-specific and a panel of serotype-cross-reactive human CD4+ cytotoxic T-lymphocyte clones.


    Gagnon, S J; Zeng, W.; Kurane, I; Ennis, F A


    We analyzed the CD4+ T-lymphocyte response of a donor who had received an experimental live-attenuated dengue 4 virus (D4V) vaccine. Bulk culture proliferative responses of peripheral blood mononuclear cells (PBMC) to noninfectious dengue virus (DV) antigens showed the highest proliferation to D4V antigen, with lesser, cross-reactive proliferation to D2V antigen. We established CD4+ cytotoxic T-lymphocyte clones (CTL) by stimulation with D4 antigen. Using recombinant baculovirus antigens, we ...

  6. The cytotoxicity of polycationic iron oxide nanoparticles: Common endpoint assays and alternative approaches for improved understanding of cellular response mechanism

    Directory of Open Access Journals (Sweden)

    Hoskins Clare


    Full Text Available Abstract Background Iron oxide magnetic nanoparticles (MNP's have an increasing number of biomedical applications. As such in vitro characterisation is essential to ensure the bio-safety of these particles. Little is known on the cellular interaction or effect on membrane integrity upon exposure to these MNPs. Here we synthesised Fe3O4 and surface coated with poly(ethylenimine (PEI and poly(ethylene glycol (PEG to achieve particles of varying surface positive charges and used them as model MNP's to evaluate the relative utility and limitations of cellular assays commonly applied for nanotoxicity assessment. An alternative approach, atomic force microscopy (AFM, was explored for the analysis of membrane structure and cell morphology upon interacting with the MNPs. The particles were tested in vitro on human SH-SY5Y, MCF-7 and U937 cell lines for reactive oxygen species (ROS production and lipid peroxidation (LPO, LDH leakage and their overall cytotoxic effect. These results were compared with AFM topography imaging carried out on fixed cell lines. Results Successful particle synthesis and coating were characterised using FTIR, PCS, TEM and ICP. The particle size from TEM was 30 nm (−16.9 mV which increased to 40 nm (+55.6 mV upon coating with PEI and subsequently 50 nm (+31.2 mV with PEG coating. Both particles showed excellent stability not only at neutral pH but also in acidic environment of pH 4.6 in the presence of sodium citrate. The higher surface charge MNP-PEI resulted in increased cytotoxic effect and ROS production on all cell lines compared with the MNP-PEI-PEG. In general the effect on the cell membrane integrity was observed only in SH-SY5Y and MCF-7 cells by MNP-PEI determined by LDH leakage and LPO production. AFM topography images showed consistently that both the highly charged MNP-PEI and the less charged MNP-PEI-PEG caused cell morphology changes possibly due to membrane disruption and cytoskeleton remodelling. Conclusions

  7. A simple method to measure cell viability in proliferation and cytotoxicity assays

    Directory of Open Access Journals (Sweden)

    Ricardo Carneiro Borra


    Full Text Available Resazurin dye has been broadly used as indicator of cell viability in several types of assays for evaluation of the biocompatibility of medical and dental materials. Mitochondrial enzymes, as carriers of diaphorase activities, are probably responsible for the transference of electrons from NADPH + H+ to resazurin, which is reduced to resorufin. The level of reduction can be quantified by spectrophotometers since resazurin exhibits an absorption peak at 600 ηm and resorufin at 570 ηm wavelengths. However, the requirement of a spectrophotometer and specific filters for the quantification could be a barrier to many laboratories. Digital cameras containing red, green and blue filters, which allow the capture of red (600 to 700 ηm and green (500 to 600 ηm light wavelengths in ranges bordering on resazurin and resorufin absorption bands, could be used as an alternative method for the assessment of resazurin and resorufin concentrations. Thus, our aim was to develop a simple, cheap and precise method based on a digital CCD camera to measure the reduction of resazurin. We compared the capability of the CCD-based method to distinguish different concentrations of L929 and normal Human buccal fibroblast cell lines with that of a conventional microplate reader. The correlation was analyzed through the Pearson coefficient. The results showed a strong association between the measurements of the method developed here and those made with the microplate reader (r² = 0.996; p < 0.01 and with the cellular concentrations (r² = 0.965; p < 0.01. We concluded that the developed Colorimetric Quantification System based on CCD Images allowed rapid assessment of the cultured cell concentrations with simple equipment at a reduced cost.

  8. Ferrocenes as potential chemotherapeutic drugs: synthesis, cytotoxic activity, reactive oxygen species production and micronucleus assay. (United States)

    Pérez, Wanda I; Soto, Yarelys; Ortíz, Carmen; Matta, Jaime; Meléndez, Enrique


    Three new ferrocene complexes were synthesized with 4-(1H-pyrrol-1-yl)phenol group appended to one of the Cp ring. These are: 1,1'-4-(1H-pyrrol-1-yl)phenyl ferrocenedicarboxylate, ('Fc-(CO2-Ph-4-Py)2'), 1,4-(1H-pyrrol-1-yl)phenyl, 1'-carboxyl ferrocenecarboxylate ('Fc-(CO2-Ph-4-Py)CO2H') and 4-(1H-pyrrol-1-yl)phenyl ferroceneacetylate ('Fc-CH2CO2-Ph-4-Py'). The new species were characterized by standard analytical methods. Cyclic voltammetry experiments showed that Fc-CH2CO2-Ph-4-Py has redox potential very similar to the Fc/Fc(+) redox couple whereas Fc-(CO2-Ph-4-Py)2 and Fc-(CO2-Ph-4-Py)CO2H have redox potentials of over 400 mV higher than Fc/Fc(+) redox couple. The in vitro studies on Fc-(CO2-Ph-4-Py)2 and Fc-(CO2-Ph-4-Py)CO2H revealed that these two compounds have moderate anti-proliferative activity on MCF-7 breast cancer cell line. In contrast Fc-CH2CO2-Ph-4-Py which displayed low anti-proliferative activity. In the HT-29 colon cancer cell line, the new species showed low anti-proliferative activity. Cytokinesis-block micronucleus assay (CBMN) was performed on these ferrocenes and it was determined they induce micronucleus formation on binucleated cells and moderate genotoxic effects on the MCF-7 breast cancer cell line. There is a correlation between the IC50 values of the ferrocenes and the amount of micronucleus formation activity on binucleated cells and the reactive oxygen species (ROS) production on MCF-7 cell line.

  9. Subtypes of cytotoxic lymphocytes and natural killer cells infiltrating cancer nests correlate with prognosis in patients with vulvar squamous cell carcinoma. (United States)

    Sznurkowski, Jacek Jan; Zawrocki, Anton; Biernat, Wojciech


    Adaptive immune effectors do not influence prognosis in vulvar squamous cell carcinoma (vSCC). Therefore, we tried to clarify the prognostic role of innate immunity and granzyme B-dependent cytotoxicity as defined by intratumoral infiltrates of natural killer cells (CD56+) and lymphocytes expressing granzyme B (GrB+). We analyzed 76 primary vSCCs and 35 lymph node metastases that were obtained from 76 patients with a full clinical history. The distribution and density of GrB+ and CD56+ cells within cancer tissues were evaluated by immunohistochemistry and correlated with clinicopathological features, commonly recognized prognostic factors and overall survival (OS). CD56+ cells were mostly detected within the cancer nests, while GrB+ cells were predominant in the tumor stroma. Intraepithelial (IE) CD56+ infiltrates at the primary site were correlated with depth of invasion (r = 0.339, p = 0.003) and recurrence (r = 0.295, p = 0.011), while IE GrB+ infiltrates were correlated with tumor grade (r = 0.304, p = 0.009) and age (r = 0.333, p = 0.004). The primary cancer nests of metastatic patients were infiltrated more by intraepithelial (IE) CD56+ cells than were those of the non-metastatic patients (p = 0.05). The median OS was 41.16 months (range 1.7-98.43). High IE GrB+ infiltrates predicted longer OS among patients without metastases (p = 0.028). High IE CD56+ infiltrates were correlated with longer OS in metastatic cases (p = 0.009). The combined cytotoxicity of innate and adaptive immune effectors infiltrating cancer nests (IE GrB+) predicts an improved clinical outcome among non-metastatic vSCC patients. The functional status of prognostic IE CD56+ infiltrates in immune escaped (metastatic) tumors requires further investigation.

  10. TCR gamma delta cytotoxic T lymphocytes expressing the killer cell-inhibitory receptor p58.2 (CD158b) selectively lyse acute myeloid leukemia cells. (United States)

    Dolstra, H; Fredrix, H; van der Meer, A; de Witte, T; Figdor, C; van de Wiel-van Kemenade, E


    Cytotoxic T lymphocytes (CTL) are thought to play an important role in the graft-versus-leukemia (GVL) response. Unfortunately, GVL reactivity is often associated with life-threatening graft-versus-host disease (GVHD). Characterization of CTL that selectively attack leukemic cells but not normal cells may lead to the development of adjuvant immunotherapy that separates GVL from GVHD. Here, we describe TCR gamma delta (V gamma 9/V delta 1) CTL, isolated from the peripheral blood of an AML patient after stem cell transplantation (SCT), that very efficiently lysed freshly isolated acute myeloid leukemia (AML) cells and AML cell lines. Interestingly, HLA-matched non-malignant hematopoietic cells were not killed. We revealed that the killer cell-inhibitory receptor (KIR) p58.2 (CD158b) specific for group 2 HLA-C molecules negatively regulates the cytotoxic effector function displayed by these TCR gamma delta CTL. First, an antibody against HLA-C enhances lysis of non-malignant cells. Secondly, stable transfection of HLA-Cw*0304 into the class I-negative cell line 721.221 inhibited lysis. Finally, engagement of p58.2 by antibodies immobilized on Fc gamma R-expressing murine P815 cells inhibits CD3- and TCR gamma delta-directed lysis. Compared to non-malignant hematopoietic cells, AML cells express much lower levels of MHC class I molecules making them susceptible to lysis by p58.2(+) TCR gamma delta CTL. Such KIR-regulated CTL reactivity may have a role in the GVL response without affecting normal tissues of the host and leading to GVHD.

  11. An impedance-based cytotoxicity assay for real-time and label-free assessment of T-cell-mediated killing of adherent cells. (United States)

    Peper, Janet Kerstin; Schuster, Heiko; Löffler, Markus W; Schmid-Horch, Barbara; Rammensee, Hans-Georg; Stevanović, Stefan


    The in vitro assessment of T-cell-mediated cytotoxicity plays an important and increasingly relevant role both in preclinical target evaluation and during immunomonitoring to accompany clinical trials employing targeted immunotherapies. For a long time, the gold standard for this purpose has been the chromium release assay (CRA). This end point assay, however, shows several disadvantages including the inevitable use of radioactivity. Based on electrical impedance measurements (using the xCELLigence system), we have established a label-free assay, facilitating the real-time monitoring of T-cell-mediated cytotoxicity. The coculture of peptide-specific T-cell lines with peptide-loaded target cells reproducibly led to a decrease in impedance due to induced apoptosis and detachment of target cells. Comparing our results to the standard CRA assay, we could demonstrate that impedance-based measurements show comparable results after short incubation periods (6h) but outperform the CRA both in reproducibility and sensitivity after prolonged incubation (24h), enabling the detection of target cell lysis with an effector to target ratio as low as 0.05:1. The impedance-based assay represents a valuable and highly sensitive tool for label-free real-time high throughput analysis of T-cell-mediated cytotoxicity.

  12. Cytotoxicity of lymphocytes activated by superantigen toxic-shock-syndrome toxin-1 against colorectal cancer LoVo cells. (United States)

    Wang, Wei; Sun, Xuejun; Lu, Le; Zheng, Jian-Bao; Tian, Yong; Wang, Wei


    Toxic-shock-syndrome toxin-1 (TSST-1), a superantigen, can stimulate T cell activation and be used for immunotherapy. In this study, we employed the carcinoembryonic antigen (CEA)-positive LoVo cells to test whether retrovirus-mediated TSST-1 expression could activate human T cells and promote cytotoxicity against tumor cells. We first generated plasmids of pLEGFP-N1-5HRE-CEAp-TSST-1-linker-CD80TM containing a fusion gene of the CEA promoter, 5 copies of the hypoxia-response elements (HRE) as an enhancer, the fragments for TSST-1, and the transmembrane domain of CD80 (CD80TM) and control pLEGFP-N1-5HRE-CEAp (without TSST-1) and generated retroviruses of 5HCTC and 5HC, respectively. After infection with 5HC and 5HCTC retroviruses to establish cell lines, the high levels of TSST-1 expression were observed on the membrane and cytoplasm of the 5HCTC-infected LoVo cells, particularly culture under a hypoxic condition, but not on CEA(-) HeLa cells. Furthermore, the TSST-1-expressing LoVo cell lysates, but not the control cell lysates, stimulated human T cell proliferation, and the co-culture of the TSST-1-expressing LoVo, but not control cells, with human peripheral blood mononuclear cells (PBMC) induced a high frequency of TNF-α- and IL-2-secreting T cells in vitro, particularly under hypoxic conditions. More importantly, co-culture of the TSST-1-expressing LoVo cells, particularly under hypoxic conditions, but not control cells, with different numbers of PBMC promoted potent cytotoxicity against LoVo cells in a dose-dependent manner in vitro. These data provide proof of the principle that selective induction of TSST1 expression in CEA(+) colorectal cancer (CRC) cells activates T cells that destroy tumor cells, particularly under a hypoxic condition. Therefore, our findings may aid in the design of new immunotherapy for the intervention of CRC at clinic.

  13. Recombinant mammaglobin A adenovirus-infected dendritic cells induce mammaglobin A-specific CD8+ cytotoxic T lymphocytes against breast cancer cells in vitro.

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    Huixia Cui

    Full Text Available Mammaglobin A (MGBA is a novel breast cancer-associated antigen almost exclusively over-expressed in primary and metastatic human breast cancers, making it a potential therapeutic target for breast cancer. The development of dendritic cell (DC-induced tumor antigen specific CD8(+ cytotoxic T lymphocytes (CTLs may hold promise in cancer immunotherapy. In this study we constructed recombinant replication-defective adenoviral (Ad vectors encoding MGBA and evaluated their ability to trigger anti-tumor immunity in vitro. DCs were isolated from the human peripheral blood monocyte cells (PBMCs of two HLA-A33(+ healthy female volunteers, and infected with adenovirus carrying MGBA cDNA (Ad-MGBA. After that, the Ad-MGBA-infected DCs were used to stimulate CD8(+ CTLs in vitro and the latter was used for co-culture with breast cancer cell lines. The data revealed that infection with Ad-MGBA improved DC maturation and up-regulated the expression of co-stimulatory molecules and the secretion of interleukin-12 (IL-12, but down-regulated interleukin-10 (IL-10 secretion from DCs. Ad-MGBA-infected DC-stimulated CD8(+CTLs displayed the highest cytotoxicity towards HLA-A33(+/MGBA(+ breast cancer MDA-MB-415 cells compared with other CD8(+CTL populations, and compared with the cytotoxicity towards HLA-A33(-/MGBA(+ breast cancer HBL-100 cells and HLA-A33(-/MGBA(- breast cancer MDA-MB 231 cells. In addition, Ad-MGBA-infected DC-stimulated CD8(+ CTLs showed a high level of IFNγ secretion when stimulated with HLA-A33(+/MGBA(+ breast cancer MDA-MB-415 cells, but not when stimulated with HLA-A33(-/MGBA(+ HBL-100 and HLA-A33(-/MGBA(-MDA-MB-231 cells. In addition, killing of CD8(+CTLs against breast cancer was in a major histocompability complex (MHC-limited pattern. Finally, the data also determined the importance of TNF-α in activating DCs and T cells. These data together suggest that MGBA recombinant adenovirus-infected DCs could induce specific anti-tumor immunity

  14. In vitro cytotoxicity studies on Carissa congesta, Polyalthia longifolia, and Benincasa hispida extracts by Sulforhodamine B assay method

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    Gaurav Mahesh Doshi


    Full Text Available Background: Indian medicinal plants have contributed to the growth of world′s ethnopharmacological heritage. Roots of Carissa congesta (CC powder are mixed with horse urine, lime juice, and camphor and used as remedies for relieving itching conditions, Polyalthia longifolia (PL leaves are aromatic and used for decoration in festivals as sonamukhi and Benincasa hispida (BH seeds provide treatment for cough and vitiated conditions of pitta. Aims of the Study: In the current studies, crude petroleum ether extracts (BH and CC and ethanolic extract of (PL were screened for in vitro cytotoxicity activity using different cell lines. Settings and Design: In the experiment, human colon cancer HCT15, human breast cancer MCF7 and human leukemia MOLT4 cell lines were studied on the extracts. Materials and Methods: The method used was Sulforhodamine B (SRB assay method in which growth inhibition of 50% (GI 50 was analyzed by comparing it with standard drug Adriamycin (ADR (doxorubicin. Results: The CC and PL extracts showed equivalent activity to ADR (doxorubicin for human breast cancer cell line MCF7 and human leukemia cell line MOLT4 respectively. BH extract did not show satisfactory activity on selected cell lines. Conclusion: In the future, new cell lines may be screened in order to check the potency of CC, PL, and BH extracts.

  15. Polymeric nanoparticles for oral delivery of 5-fluorouracil: Formulation optimization, cytotoxicity assay and pre-clinical pharmacokinetics study. (United States)

    Mattos, Ana Cristina de; Altmeyer, Clescila; Tominaga, Tania Toyomi; Khalil, Najeh Maissar; Mainardes, Rubiana Mara


    Poly(lactic acid) (PLA) or poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) blend nanoparticles were developed loading 5-fluorouracil (5-FU), an antitumor agent broadly used in therapy. A 2(3) factorial experimental design was conducted to indicate an optimal formulation and demonstrate the influence of the interactions of components on the mean particle size and drug encapsulation efficiency. Optimized PLA nanoparticles presented 294nm and 51% of 5-FU encapsulation efficiency and PLA-PEG blend nanoparticles presented 283nm and 55% of 5-FU encapsulation efficiency. In vitro release assay demonstrated after 320h about 50% of 5-FU was released from PLA and PLA-PEG blend nanoparticles. Release kinetics of 5-FU from nanoparticles followed second order and the release mechanism calculated by Korsmeyer-Peppas model was diffusion and erosion. In the assessment of cytotoxicity over Hep-2 tumor cells, PLA or PLA-PEG blend nanoparticles presented similar IC50 value than free 5-FU. Pharmacokinetic parameters after oral administration of 5-FU were improved by nanoencapsulation. Bioavailability, Cmax, Tmax, t1/2 and distribution volume were significantly improved, while clearance were decreased. PEG presence in nanoparticles didn't influence physicochemical and biological parameters evaluated. PLA and PLA-PEG nanoparticles can be potential carriers for oral delivery of 5-FU.

  16. Increasing a Robust Antigen-Specific Cytotoxic T Lymphocyte Response by FMDV DNA Vaccination with IL-9 Expressing Construct

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    Qiang Zou


    Full Text Available Various chemokines and cytokines as adjuvants can be used to improve efficacy of DNA vaccination. In this study, we sought to investigate if a DNA construct expressing IL-9 (designed as proV-IL9 as a molecular adjuvant enhance antigen specific immune responses elicited by the pcD-VP1 DNA vaccination. Mice immunized with pcD-VP1 combined with proV-IL9 developed a strong humoral response. In addition, the coinoculation induced significant higher level of antigen-specific cell proliferation and cytotoxic response. This agreed well with higher expression level of IFN-γ and perforin in CD8+ T cells, but not with IL-17 in these T cells. The results indicate that IL-9 induces the development of IFN-γ-producing CD8+ T cells (Tc1, but not the IL-17-producing CD8+ T cells (Tc17. Up-regulated expressions of BCL-2 and BCL-XL were exhibited in these Tc1 cells, suggesting that IL-9 may trigger antiapoptosis mechanism in these cells. Together, these results demonstrated that IL-9 used as molecular adjuvant could enhance the immunogenicity of DNA vaccination, in augmenting humoral and cellular responses and particularly promoting Tc1 activations. Thus, the IL-9 may be utilized as a potent Tc1 adjuvant for DNA vaccines.

  17. The PD-1/PD-L1 (B7-H1 Pathway in Chronic Infection-Induced Cytotoxic T Lymphocyte Exhaustion

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    Kimberly A. Hofmeyer


    Full Text Available Cytotoxic CD8 T lymphocytes (CTLs play a pivotal role in the control of infection. Activated CTLs, however, often lose effector function during chronic infection. PD-1 receptor and its ligand PD-L1 of the B7/CD28 family function as a T cell coinhibitory pathway and are emerging as major regulators converting effector CTLs into exhausted CTLs during chronic infection with human immunodeficiency virus, hepatitis B virus, hepatitis C virus, and other pathogens capable of establishing chronic infections. Importantly, blockade of the PD-1/PD-L1 pathway is able to restore functional capabilities to exhausted CTLs and early clinical trials have shown promise. Further research will reveal how chronic infection induces upregulation of PD-1 on CTLs and PD-L1 on antigen-presenting cells and other tissue cells and how the PD-1/PD-L1 interaction promotes CTLs exhaustion, which is crucial for developing effective prophylactic and therapeutic vaccination against chronic infections.

  18. Therapeutic efficacy of MUC1-specific cytotoxic T lymphocytes and CD137 co-stimulation in a spontaneous breast cancer model. (United States)

    Mukherjee, Pinku; Tinder, Teresa L; Basu, Gargi D; Pathangey, Latha B; Chen, Lieping; Gendler, Sandra J


    To study immunology in breast tumors, we have utilized a mammary gland adenocarcinoma model in which mice develop spontaneous tumors of the mammary gland which are initiated at puberty and express a human tumor antigen, MUC1. MUC1 (CD227) is over-expressed in 90% of human breast cancers and its glycosylation status and pattern of expression in cancer cells is altered. Humoral and cellular responses to MUC1 have been reported in breast cancer patients and therefore, MUC1 is being evaluated as a target for immune intervention. This mouse model of spontaneous breast cancer allows the evaluation of anti-MUC1 immune responses at all stages of the disease. In this report, we review the model as it pertains to a) the development of the tumor, b) MUC1 expression, and the native immune responses against MUC1 as tumors progress, and c) the immune suppressive microenvironment within the developing tumor. Finally, we report our latest findings describing the therapeutic efficacy of adoptively transferred MUC1-specific cytotoxic T lymphocytes (MUC1-CTL) in these mice and discuss ways to increase their effectiveness by agonistic monoclonal antibody against CD137 T cell costimulatory molecule.

  19. CD69 expression potentially predicts response to bendamustine and its modulation by ibrutinib or idelalisib enhances cytotoxic effect in chronic lymphocytic leukemia (United States)

    Roldán, Jocabed; Jiménez, Laura; Cabezas, Sandra; Clot, Guillem; Pinyol, Magda; Xargay-Torrent, Sílvia; Rosich, Laia; Arimany-Nardí, Cristina; Aymerich, Marta; Villamor, Neus; López-Guillermo, Armando; Pérez-Galán, Patricia; Roué, Gaël; Pastor-Anglada, Marçal; Campo, Elías; López-Guerra, Mónica; Colomer, Dolors


    Clinical responses to bendamustine in chronic lymphocytic leukemia (CLL) are highly heterogeneous and no specific markers to predict sensitivity to this drug have been reported. In order to identify biomarkers of response, we analyzed the in vitro activity of bendamustine and the gene expression profile in primary CLL cells. We observed that mRNA expression of CD69 (CD69) and ITGAM (CD11b) constitute the most powerful predictor of response to bendamustine. When we interrogated the predictive value of the corresponding cell surface proteins, the expression of the activation marker CD69 was the most reliable predictor of sensitivity to bendamustine. Importantly, a multivariate analysis revealed that the predictive value of CD69 expression was independent from other clinico-biological CLL features. We also showed that when CLL cells were co-cultured with distinct subtypes of stromal cells, an upregulation of CD69 was accompanied by a reduced sensitivity to bendamustine. In agreement with this, tumor cells derived from lymphoid tumor niches harbored higher CD69 expression and were less sensitive to bendamustine than their peripheral blood counterparts. Furthermore, pretreatment of CD69 high CLL cases with the B-cell receptor (BCR) pathway inhibitors ibrutinib and idelalisib decreased CD69 levels and enhanced bendamustine cytotoxic effect. Collectively, our findings indicate that CD69 could be a predictor of bendamustine response in CLL patients and the combination of clinically-tested BCR signaling inhibitors with bendamustine may represent a promising strategy for bendamustine low responsive CLL cases. PMID:26701728

  20. Demethylation of Cancer/Testis Antigens and CpG ODN Stimulation Enhance Dendritic Cell and Cytotoxic T Lymphocyte Function in a Mouse Mammary Model

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    Jun-Zhong Sun


    Full Text Available Background. Cancer/testis antigens (CTAs are ideal targets for cancer immunotherapy in virtue of their restricted expression profile in normal tissues. However, CTA-targeted immunotherapy has been rather disappointing clinical setting for CTAs are downregulated by cytosine-phosphate-guanosine (CpG methylation in their promoter regions, so that tumor cells have low immunogenicity. Methods. We reinduced mouse CTA P1A through demethylation process and generated P1A-specific cytotoxic lymphocytes (CTLs by immunizing BALB/c (H-2d mice with dendritic cells pulsed with a P1A-specific peptide and CpG oligodeoxynucleotide (ODN immune adjuvant. Results. We found that demethylation and CpG ODN immune adjuvant stimulation facilitated DC maturation and enhanced the allogenic capacity of P1A-specific CTLs against target cells both in vitro and in vivo. Conclusions. Our results suggested that CTA induction and immune adjuvant stimulation is a feasible strategy in cancer immunotherapy.

  1. Cytotoxic T lymphocyte-associated antigen 4 plays an essential role in the function of CD25(+)CD4(+) regulatory cells that control intestinal inflammation. (United States)

    Read, S; Malmström, V; Powrie, F


    It is now clear that functionally specialized regulatory T (Treg) cells exist as part of the normal immune repertoire, preventing the development of pathogenic responses to both self- and intestinal antigens. Here, we report that the Treg cells that control intestinal inflammation express the same phenotype (CD25(+)CD45RB(low)CD4(+)) as those that control autoimmunity. Previous studies have failed to identify how CD25(+) Treg cells function in vivo. Our studies reveal that the immune-suppressive function of these cells in vivo is dependent on signaling via the negative regulator of T cell activation cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), as well as secretion of the immune-suppressive cytokine transforming growth factor beta. Strikingly, constitutive expression of CTLA-4 among CD4(+) cells was restricted primarily to Treg cells, suggesting that CTLA-4 expression by these cells is involved in their immune-suppressive function. These findings raise the possibility that Treg cell function contributes to the immune suppression characteristic of CTLA-4 signaling. Identification of costimulatory molecules involved in the function of Treg cells may facilitate further characterization of these cells and development of new therapeutic strategies for the treatment of inflammatory diseases.

  2. Dendritic cells pulsed with alpha-fetoprotein and mutant P53 fused gene induce bi-targeted cytotoxic T lymphocyte response against hepatic carcinoma. (United States)

    Ren, Jun; Jia, Jun; Zhang, Hongmei; Zhang, Liwang; Ma, Bo; Jiang, Hanfang; Di, Lijun; Song, Guohong; Yu, Jing


    Dendritic cell (DC)-based immunotherapy is rapidly emerging as a promising treatment in cancer therapy. We had previously shown that DC pulsed with either defined mRNA of tumor antigen (Ag) such as alpha-fetoprotein (AFP), or total RNA of hepatocellular carcinoma (HCC) could elicit Ag-specific cytotoxic T lymphocyte (CTL) response. Therefore, we suggested a novel DC-based therapeutic method, in which DCs derived from CD34(+) cells enriched peripheral blood mononuclear cells were pulsed with liposome-coated AFP and mutant P53 (mtP53) fused gene pEGFP-C3/AFP-mtP53 to induce bi-targeted specific CTL responses against HCC. Three different genotype HCC cell lines, HepG2 (human histocompatibility leukocyte antigens (HLA) A2 positive, AFP expressing positive, P53 expressing negative), SMMC7721 (HLA A2 positive, neither AFP nor P53 expressing positive), and HMCC97 (HLA A2 positive, both AFP and P53 expressing positive) were selected as targets for CTL responses. An important finding was that DCs pulsed with the liposome-coated fused gene could evoke more intensive bi-targeted Ag-specific CTL responses against HMCC97 than DCs pulsed with either AFP or P53 single gene (P gene of different Ags might induce more extensive multitargeted antitumor immunity.

  3. Interferon-gamma Inhibits Melanogenesis and Induces Apoptosis in Melanocytes: A Pivotal Role of CD8+ Cytotoxic T Lymphocytes in Vitiligo. (United States)

    Yang, Lili; Wei, Yi; Sun, Yue; Shi, Weimin; Yang, Ji; Zhu, Lubing; Li, Ming


    Increased expression of the cytokine interferon (IFN)-γ plays a pivotal role in vitiligo-induced depigmentation. However, the major source of IFN-γ in vitiligo patients and the mechanisms underlying melanocyte destruction are unknown. In this study, a large number of skin infiltrating IFN-γ+ cells and CD8+ T cells were detected in progressive vitiligo. Among the peripheral blood mononuclear cells (PBMCs) of vitiligo patients, CD8+ cytotoxic T lymphocytes (CTLs) that express IFN-γ exhibited significant expansion, which suggests that activated CTLs are the main source of increased IFN-γ in progressive vitiligo. An in vitro analysis demonstrated that IFN-γ inhibits melanogenesis in primary cultured human melanocytes by altering melanogenic enzyme mRNA expression and, more importantly, that IFN-γ directly induces melanocyte apoptosis. Our data indicate that vitiligo pathophysiology may be linked to globally activated CD8+ CTL subpopulations, which produce increased IFN-γ and induce melanocyte dysfunction and apoptosis.

  4. Association of cytotoxic T-lymphocyte antigen 4 +49A/G gene polymorphism with acute rejection risk in renal transplantation. (United States)

    Yang, Chun-Hua; Chen, Xue-Xia; Chen, Li; Zheng, Dong-Hua; Liu, Qiong-Shan; Xie, Wen-Feng


    The conclusions on the association between cytotoxic T-lymphocyte antigen 4 (CTLA4) +49A/G gene polymorphism and acute rejection risk in renal transplantation are still debated. This meta-analysis was performed to update the association between CTLA4 +49A/G and acute rejection risk in renal transplantation. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Fourteen reports were included into this meta-analysis for the association of CTLA4 A/G gene polymorphism and acute rejection risk in renal transplantation, consisting of 962 acute rejection patients and 2084 non-acute rejection controls. The association between CTLA4 G allele/GG genotype and acute rejection risk in renal transplantation was found in this meta-analysis (G allele: OR=1.21, 95% CI: 1.03-1.44, P=.02; GG genotype: OR=1.37, 95% CI: 1.10-1.69, P=.004). However, the AA genotype was not associated with acute rejection risk in renal transplantation. In conclusion, CTLA4 G allele/GG genotype is associated with the acute rejection risk in renal transplantation.

  5. Global Gene Expression Profiling in Interleukin-12-Induced Activation of CD8+ Cytotoxic T Lymphocytes against MouseMammary Carcinoma

    Institute of Scientific and Technical Information of China (English)

    ShanjinCao; ZhaoyingXiang; XiaojingMa


    Interleukin-12 (IL-12) is a critical cytokine representing the link between the cellular and humoral branches of host immune defense apparatus. IL-12-induced cytotoxic lymphocyte (CTL) development is a central mechanism in immune responses against intracellular infectious agents as well as malignant growth. However,the molecular basis of tumor-specific CTL responses mediated by IL-12 remains poorly defined. In this study,we addressed this issue in a comprehensive manner to probe into IL-12-induced anti-tumor responses by global gene expression profiling of mRNA expression in CD8+T cells in a transplantable syngeneic mouse mammarycarcinoma model treated or not with recombinant IL-12. A strong tumor regression was induced by the IL-12 treatment. An introspection of differential gene expression at an early stage of the IL-12-initiated CTL activation reveals interesting genes and molecular pathways that may account for the marked tumor regression,and is likely to provide a rich source of potential targets for further research and development of effective therapeutic modalities. Cellular & Molecular Immunology. 2004;1(5):357-366.

  6. Cytotoxic T lymphocytes and CD4 epitope mutations in the pre-core/core region of hepatitis B virus in chronic hepatitis B carriers in Northeast Iran. (United States)

    Zhand, Sareh; Tabarraei, Alijan; Nazari, Amineh; Moradi, Abdolvahab


    Hepatitis B virus (HBV) is vulnerable to many various mutations. Those within epitopes recognized by sensitized T cells may influence the re-emergence of the virus. This study was designed to investigate the mutation in immune epitope regions of HBV pre-core/core among chronic HBV patients of Golestan province, Northeast Iran. In 120 chronic HBV carriers, HBV DNA was extracted from blood plasma samples and PCR was done using specific primers. Direct sequencing and alignment of the pre-core/core region were applied using reference sequence from Gene Bank database (Accession Number AB033559). The study showed 27 inferred amino acid substitutions, 9 of which (33.3%) were in CD4 and 2 (7.4%) in cytotoxic T lymphocytes' (CTL) epitopes and 16 other mutations (59.2%) were observed in other regions. CTL escape mutations were not commonly observed in pre-core/core sequences of chronic HBV carriers in the locale of study. It can be concluded that most of the inferred amino acid substitutions occur in different immune epitopes other than CTL and CD4.

  7. Definition of an epitope on Japanese encephalitis virus (JEV) envelope protein recognized by JEV-specific murine CD8+ cytotoxic T lymphocytes. (United States)

    Takada, K; Masaki, H; Konishi, E; Takahashi, M; Kurane, I


    We defined an epitope on the Japanese encephalitis virus (JEV) envelope (E) protein recognized by CD8+ cytotoxic T lymphocytes (CTLs). CTLs induced in JEV-infected BALB/c (H-2d) mice recognized E and/or premembrane (PrM) proteins, while CTLs in C57BL/6J (H-2b) and C3H/HeJ (H-2k) mice did not. JEV-specific CTLs had a phenotype of CD3+ CD4- CD8+. Twenty-four 9-amino acid (a.a.) peptides, which had binding motifs for H-2Kd, H-2Ld or H-2Dd, were synthesized according to the amino acid sequences of PrM and E proteins. CTLs induced by JEV infection recognized only the peptide K-3. Immunization of BALB/c mice with only a group of peptides including K-3 induced CTLs which recognized the homologous K-3 peptide, while immunization with other peptides did not. The peptide K-3 had a binding motif for H-2Kd. This is consistent with the finding that JEV-specific CTLs in BALB/c mice was H-2Kd-restricted. These results indicate that the epitope recognized by CTLs in BALB/c mice is located between a.a. 60 and 68 on the E protein, corresponding to an a.a. sequence of CYHASVTDI.

  8. Combined assay of surface immunoglobulin intensity and mouse rosettes. A practical parameter in the differential diagnosis of small lymphocytic and follicular center cell lymphomas. (United States)

    Batata, A; Shen, B


    Cell suspensions from the lymph nodes of small lymphocytic lymphoma (n = 94) and nodular and diffuse follicular center cell lymphomas (n = 330) were analyzed to evaluate the diagnostic significance of the surface immunoglobulin (SIg) intensity and mouse rosette assay (MR). In small lymphocytic lymphoma, SIg was monoclonal in 65 cases (69.15%), with weak fluorescence in 59 (90.77%). It was not detected in 29 cases (30.85%). The MR findings were positive in 68 cases (72.34%) and negative in 26 (27.66%). The combined results of these two assays showed the following: weak SIg/MR+, 35 (37.23%); weak SIg/MR-, 24 (25.53%); strong SIg/MR+, 6 (6.38%); strong SIg/MR-, 0; undetected SIg/MR+, 27 (28.72%); and undetected SIg/MR-, 2 (2.13%). By performing the assays for these two markers and accepting weak SIg/MR+, weak SIg/MR-, strong SIg/MR+, or undetected SIg/MR+ as sufficient for diagnosis, 92 cases (97.87%) were diagnosed. In diffuse follicular center cell lymphomas, SIg was monoclonal in 287 cases (86.97%), with strong fluorescence in 258 (89.9%) and weak fluorescence in 29 (10.1%). It was not detected in 43 cases (13.03%). The MR results were positive in 34 cases (10.3%) and negative in 296 (89.7%). The combined findings of these two assays showed that strong SIg/MR- was present in 244 cases (73.94%). The diagnostic value of the combined assay in the differential diagnosis between small lymphocytic lymphoma and diffuse follicular center cell lymphomas was proved using five statistical parameters.

  9. Activated peripheral lymphocytes with increased expression of cell adhesion molecules and cytotoxic markers are associated with dengue fever disease

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    Elzinandes L Azeredo


    Full Text Available The immune mechanisms involved in dengue fever and dengue hemorrhagic/dengue shock syndrome are not well understood. The ex vivo activation status of immune cells during the dengue disease in patients was examined. CD4and CD8 T cells were reduced during the acute phase. Interestingly, CD8 T cells co-expressing activation marker HLA-DR, Q, P, and cytolytic granule protein-Tia-1 were significantly higher in dengue patients than in controls. Detection of adhesion molecules indicated that in dengue patients the majority of T cells (CD4 and CD8 express the activation/memory phenotype, characterized as CD44HIGH and lack the expression of the naïve cell marker, CD62L LOW. Also, the levels of T cells co-expressing ICAM-1 (CD54, VLA-4, and LFA-1 (CD11a were significantly increased. CD8 T lymphocytes expressed predominantly low levels of anti-apoptotic molecule Bcl-2 in the acute phase, possibly leading to the exhibition of a phenotype of activated/effector cells. Circulating levels of IL-18, TGF-b1 and sICAM-1 were significantly elevated in dengue patients. Early activation events occur during acute dengue infection which might contribute to viral clearance. Differences in expression of adhesion molecules among CD4 and CD8 T cells might underlie the selective extravasation of these subsets from blood circulation into lymphoid organs and/or tissues. In addition, activated CD8 T cells would be more susceptible to apoptosis as shown by the alteration in Bcl-2 expression. Cytokines such as IL-18, TGF-b1, and sICAM-1 may be contributing by either stimulating or suppressing the adaptative immune response, during dengue infection, thereby perhaps establishing a relationship with disease severity.

  10. Activated peripheral lymphocytes with increased expression of cell adhesion molecules and cytotoxic markers are associated with dengue fever disease. (United States)

    Azeredo, Elzinandes L; Zagne, Sonia M O; Alvarenga, Allan R; Nogueira, Rita M R; Kubelka, Claire F; de Oliveira-Pinto, Luzia M


    The immune mechanisms involved in dengue fever and dengue hemorrhagic/dengue shock syndrome are not well understood. The ex vivo activation status of immune cells during the dengue disease in patients was examined. CD4 and CD8 T cells were reduced during the acute phase. Interestingly, CD8 T cells co-expressing activation marker HLA-DR, Q, P, and cytolytic granule protein-Tia-1 were significantly higher in dengue patients than in controls. Detection of adhesion molecules indicated that in dengue patients the majority of T cells (CD4 and CD8) express the activation/memory phenotype, characterized as CD44HIGH and lack the expression of the naïve cell marker, CD62L LOW. Also, the levels of T cells co-expressing ICAM-1 (CD54), VLA-4, and LFA-1 (CD11a) were significantly increased. CD8 T lymphocytes expressed predominantly low levels of anti-apoptotic molecule Bcl-2 in the acute phase, possibly leading to the exhibition of a phenotype of activated/effector cells. Circulating levels of IL-18, TGF-b1 and sICAM-1 were significantly elevated in dengue patients. Early activation events occur during acute dengue infection which might contribute to viral clearance. Differences in expression of adhesion molecules among CD4 and CD8 T cells might underlie the selective extravasation of these subsets from blood circulation into lymphoid organs and/or tissues. In addition, activated CD8 T cells would be more susceptible to apoptosis as shown by the alteration in Bcl-2 expression. Cytokines such as IL-18, TGF-b1, and sICAM-1 may be contributing by either stimulating or suppressing the adaptative immune response, during dengue infection, thereby perhaps establishing a relationship with disease severity.

  11. Monoclonal antibody against IFN-gamma inhibits Moloney murine sarcoma virus-specific cytotoxic T lymphocyte differentiation

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    Zanovello, P.; Vallerani, E.; Biasi, G.; Landolfo, S.; Collavo, D.


    The role of autochthonous IFN- production was evaluated in immune reactions to Moloney murine sarcoma virus (M-MSV)-induced tumors which are characterized by spontaneous regression mainly caused by virus-specific CTL activity. A functional IFN- depletion, induced by repeated administration of mAb anti-IFN- at the site of virus inoculation, prevented tumor regression in M-MSV-injected mice. Moreover, this antibody inhibited in vitro both proliferation and differentiation of M-MSV-specific T lymphocytes obtained in bulk cultures, but not growth and lytic activity of the already differentiated virus-specific CTL clone CHM-14 stimulated with rIL-2 and relevant tumor Ag. In addition, in mice receiving mAb treatment the frequency of M-MSV-specific CTL precursors, evaluated by means of limiting dilution analysis, was strongly reduced in comparison with that of control mice injected only with virus. Because CTL secrete IFN- following antigenic stimulation, the possibility that non-T effector cells recruited by this lymphokine might mediate tumor regression was also considered. Adoptive immunotherapy experiments, performed in T cell-deficient (Tx + BM) and in sublethally irradiated mice, demonstrated that transfer of CHM-14 CTL clone, which secretes IFN-, was able to counteract M-MSV tumor growth despite the local mAb anti-IFN- treatment which may have prevented host cell recruitment. Moreover, repeated local rIFN- inoculations in Tx + BM mice did not counteract M-MSV tumor progression, thus confirming that other IFN- properties such as non-T cell recruitment, antiviral or anti-proliferative IFN- activities have little or no relevance when M-MSV-specific CTL are lacking. On the whole, these results indicate that in M-MSV-injected mice, tumor enhancement after mAb anti-IFN- treatment is principally caused by impaired differentiation of virus-specific CTL precursors.

  12. Procedure for preparing peptide-major histocompatibility complex tetramers for direct quantification of antigen-specific cytotoxic T lymphocytes

    Institute of Scientific and Technical Information of China (English)

    Xian-Hui He; Li-Hui Xu; Yi Liu


    AIM: To establish a simplified method for generating peptide-major histocompatibility complex (MHC) class I tetramers.METHODS: cDNAs encoding the extracellular domain of human lymphocyte antigen (HLA)-A*0201 heavy chain (A2) and β2-microglobulin (β2m) from total RNA extracted from leukocytes of HLA-A2+ donors were doned into separate expression vectors by reverse transcription-polymerase chain reaction. The recombinant A2 and β2m proteins were expressed in Escherichia coli strain BL21(DE3) and recovered from the inclusion body fraction. Soluble A2 proteins loaded with specific antigen peptides were refolded by dilution from the heavy chain in the presence of light chain β2m and HLA-A2-restricted peptide antigens. The refolded A2monomers were biotinylated with a commercial biotinylation enzyme (BirA) and purified by low pressure anion exchange chromatography on a Q-Sepharose (fast flow) column.The tetramers were then formed by mixing A2 monomers with streptavidin-PE in a molar ratio of 4:1. Flow cytometry was used to confirm the expected tetramer staining of CD8+ T cells.RESULTS: Recombinant genes for HLA-A*0201 heavy chain (A2) fused to a BirA substrate peptide (A2-BSP) and mature β2m from HLA-A2+ donor leukocytes were successfully doned and highly expressed in E. coli. Two soluble monomeric A2-peptide complexes were reconstituted from A2-BSP in the presence of β2m and peptides loaded with either human cytomegalovirus pp65495-503 peptide (NLVPMVATV,NLV; designated as A2-NLV) or influenza virus matrix protein Mp58-66 peptide (GILGFVFTL, GIL; designated as A2-GIL). Refolded A2-NLV or A2-GIL monomers were biotinylated and highly purified by single step anion exchange column chromatography. The tetramers were then formed by mixing the biotinylated A2-NLV or A2-GIL monomers with streptavidin-PE, leading to more than 80% multiplication as revealed by SDS-PAGE under non-reducing, unboiled conditions. Flow cytometry revealed that these tetramers could specifically

  13. Application of Comet assay to assess the effects of white bean meal on DNA of human lymphocytes

    Directory of Open Access Journals (Sweden)

    Luciana Lopes Silva Pereira


    Full Text Available This study was conducted to evaluate the potential induction of genotoxic effects of white bean flour using the Comet assay. The test was conducted with human lymphocytes present in whole blood immediately after collection, by incubation with white bean flour in three concentrations (3.92, 9.52 and 18.18 mg/mL at 37 ºC for 4 h followed by preparation of slides. Samples were considered positive (above 20% damage when the damage observed to cellular DNA was higher than the negative control. No genotoxic potential was found at the doses tested. However, it would be premature to suggest absence of risk to human health of DNA damage since the exposure of cells to the extract was restricted to four hours rather than a whole cell cycle. Additionally, further information on toxicology should be obtained in future studies.Este estudo foi realizado para avaliar o potencial de indução de efeitos genotóxicos da farinha de feijão branco utilizando o teste do Cometa. O ensaio foi realizado com linfócitos humanos presentes no sangue imediatamente após a coleta, por incubação com farinha de feijão branco em três concentrações (3,92, 9,52 e 18,18 mg/mL a 37 ºC por 4 h, seguida de preparação das lâminas. As amostras foram consideradas positivas (acima de 20% de dano, quando os danos observados no DNA celular foram maiores do que o controle negativo. Verificou-se que as doses testadas não mostraram potencial genotóxico. No entanto, seria prematuro fazer recomendações sobre o padrão de riscos para a saúde humana resultantes de danos ao DNA já que exposição das células ao extrato foi restrito ao período de quatro horas e não durante um ciclo celular completo. Além disso, outras informações sobre a toxicologia devem ser obtidas no futuro.

  14. Analysis of the Effects of Cell Stress and Cytotoxicity on In Vitro Assay Activity Across a Diverse Chemical and Assay Space (United States)

    U.S. Environmental Protection Agency — Chemical toxicity can arise from disruption of specific biomolecular functions or through more generalized cell stress and cytotoxicity-mediated processes. Here,...

  15. Analysis of the Effects of Cell Stress and Cytotoxicity on In Vitro Assay Activity Across a Diverse Chemical and Assay Space (United States)

    Chemical toxicity can arise from disruption of specific biomolecular functions or through more generalized cell stress and cytotoxicity-mediated processes. Here, concentration-dependent responses of 1063 chemicals including pharmaceuticals, natural products, pesticidals, consumer...

  16. Attachment of an anti-receptor antibody to non-target cells renders them susceptible to lysis by a clone of cytotoxic T lymphocytes. (United States)

    Kranz, D M; Tonegawa, S; Eisen, H N


    The molecular basis for the dependence of antigen recognition by T cells on products of the major histocompatibility complex (MHC) is unknown, and the antigenic structures that are actually bound by T-cell receptors are ill-defined. In this study, we asked whether a monoclonal antibody (mAb) that reacts with the T-cell receptor of a clone of murine cytotoxic T lymphocytes (CTL) and not with the receptors of other CTL clones can substitute for that clone's natural ligand in specific cytolytic reactions. To answer the question, a mAb (1B2) to the receptor of a CTL clone (2C) was attached covalently to 51Cr-labeled cells that were not otherwise susceptible to lysis by clone 2C, and the cells thus modified were then tested as targets for clone 2C and other CTL clones of similar specificity. All labeled cells modified in this way, including a murine cell line that expresses no cell-surface MHC class I molecules and a human cell line, were lysed by clone 2C but not by other CTL clones. If, however, instead of attaching the mAb to the receptor of clone 2C, the cells were modified by attaching to them mAbs to other surface antigens on CTL [lymphocyte function-associated antigen (LFA-1), Thy-1.2], they were not lysed. In cytolytic titrations, the cells that had been converted by attachment of mAb 1B2 into specific targets for clone 2C were just as susceptible to lysis by that clone as the clone's natural H-2d targets (e.g., P815 cells). However, some accessory surface molecules (LFA-1, Lyt-2) that are required for clone 2C to lyse its natural H-2d targets seemed not to be required for this clone to lyse the mAb-converted target cells. By demonstrating that a variety of different cell types can be thus converted into target cells for CTL, the approach described in this study may provide opportunities to analyze further the mechanisms by which CTL destroy target cells.

  17. Epstein-Barr virus-transformed B-cells as efficient antigen presenting cells to propagate Aspergillus-specific cytotoxic T-lymphocytes. (United States)

    Ramadan, Gamal


    To overcome the cytotoxic T-lymphocytes (CTL) expansion limitations imposed by the lack of sufficient dendritic cells (DC) alternative sources of autologous antigen presenting cells (APC) such as Epstein-Barr virus (EBV)-transformed B-lymphoblastoid cell lines (BLCL), which are easy to establish in vitro, have been considered and studied in the present work. Non-adherent peripheral blood mononuclear cells of three healthy donors were repeatedly primed with autologous Aspergillus fumigatus commercial culture-filtrate antigen-pulsed fast monocyte-derived DC (Aspf-CFA-DC) alone, Aspf-CFA-pulsed BLCL (Aspf-CFA-BLCL) alone or Aspf-CFA-BLCL after one, two, or three primings with Aspf-CFA-DC (1DC/BLCL, 2DC/BLCL or 3DCIBLCL; respectively). After 5th priming, lines generated by Aspf-CFA-BLCL only showed strong/weak lytic activity for EBV/Aspf; respectively. Aspf-specific lytic activity in all donors was increased by increasing the number of primings with Aspf-CFA-DC before switching to Aspf-CFA-BLCL (18.20 +/- 1.65% versus 35.67 +/- 1.02% and 40.03 +/- 1.41% in bulk cultures generated by 1DC/BLCL versus 2DC/BLCL and 3DC/BLCL, respectively). Bulk cultures generated by Aspf-CFA-BLCL after at least two primings with Aspf-CFA-DC showed approximately the same Aspf-specific lytic activity, effector cell phenotype, expansion level and percentage expression of IFN-gamma, CD69 and CD107a without any significant differences (p > 0.05) as standard bulk cultures generated by only Aspf-CFA-DC. Thus, this study explored the use of a combined DC/BLCL protocol to establish/propagate Aspf-specific CTL for adoptive immunotherapy to prevent or treat invasive pulmonary aspergillosis.

  18. A Novel CD8-Independent High-Avidity Cytotoxic T-Lymphocyte Response Directed against an Epitope in the Phosphoprotein of the Paramyxovirus Simian Virus 5 (United States)

    Gray, Peter M.; Parks, Griffith D.; Alexander-Miller, Martha A.


    Adoptive transfer studies have shown that cytotoxic T lymphocytes (CTL) of high avidity, capable of recognizing low levels of peptide-MHC I molecules, are more efficient at reducing viral titers than are low-avidity CTL, thus establishing CTL avidity as a critical parameter for the ability of a CTL to clear virus in vivo. It has been well documented that CTL of high avidity are relatively CD8 independent, whereas low-avidity CTL require CD8 engagement in order to become activated. In this study we have analyzed the antiviral CTL response elicited following infection with the paramyxovirus simian virus 5 (SV5). We have identified the immunodominant and subdominant CTL responses and subsequently assessed the avidity of these responses by their CD8 dependence. This is the first study in which the relationship between immunodominance and CTL avidity has been investigated. The immunodominant response was directed against an epitope present in the viral M protein, and subdominant responses were directed against epitopes present in the P, F, and HN proteins. Similarly to other CTL responses we have analyzed, the immunodominant response and the subdominant F and HN responses were comprised of both high- and low-avidity CTL. However, the subdominant response directed against the epitope present in the P protein is novel, as it is exclusively high avidity. This high-avidity response is independent of both the route of infection and expression by recombinant SV5. A further understanding of the inherent properties of P that elicit only high-avidity CTL may allow for the design of more efficacious vaccine vectors that preferentially elicit high-avidity CTL in vivo. PMID:11581375

  19. Identification of Immunogenic Cytotoxic T Lymphocyte Epitopes Containing Drug Resistance Mutations in Antiretroviral Treatment-Naïve HIV-Infected Individuals (United States)

    Blanco-Heredia, Juan; Lecanda, Aarón; Valenzuela-Ponce, Humberto; Brander, Christian; Ávila-Ríos, Santiago; Reyes-Terán, Gustavo


    Background Therapeutic HIV vaccines may prove helpful to intensify antiretroviral treatment (ART) efficacy and may be an integral part of future cure strategies. Methods We examined IFN-gamma ELISpot responses to a panel of 218 HIV clade B consensus-based HIV protease-reverse transcriptase peptides, designed to mimic previously described and predicted cytotoxic T lymphocyte epitopes overlapping drug resistance (DR) positions, that either included the consensus sequence or the DR variant sequence, in 49 ART-naïve HIV-infected individuals. Next generation sequencing was used to assess the presence of minority DR variants in circulating viral populations. Results Although a wide spectrum of differential magnitudes of response to DR vs. WT peptide pairs was observed, responses to DR peptides were frequent and strong in the study cohort. No difference between the median magnitudes of response to DR vs. WT peptides was observed. Interestingly, of the 22 peptides that were recognized by >15% of the participants, two-thirds (64%) corresponded to DR peptides. When analysing responses per peptide pair per individual, responses to only WT (median 4 pairs/individual) or DR (median 6 pairs/individual) were more common than responses to both WT and DR (median 2 pairs/individual; p<0.001). While the presence of ELISpot responses to WT peptides was frequently associated with the presence of the corresponding peptide sequence in the patient’s virus (mean 68% of cases), responses to DR peptides were generally not associated with the presence of DR mutations in the viral population, even at low frequencies (mean 1.4% of cases; p = 0.0002). Conclusions Our data suggests that DR peptides are frequently immunogenic and raises the potential benefit of broadening the antigens included in a therapeutic vaccine approach to immunogenic epitopes containing common DR sequences. Further studies are needed to assess the quality of responses elicited by DR peptides. PMID:26808823

  20. Sublethal exposure to alpha radiation (223Ra dichloride) enhances various carcinomas' sensitivity to lysis by antigen-specific cytotoxic T lymphocytes through calreticulin-mediated immunogenic modulation. (United States)

    Malamas, Anthony S; Gameiro, Sofia R; Knudson, Karin M; Hodge, James W


    Radium-223 dichloride (Xofigo®; 223Ra) is an alpha-emitting radiopharmaceutical FDA-approved for the treatment of bone metastases in patients with advanced castration-resistant prostate cancer. It is also being examined clinically in patients with breast and lung carcinoma and patients with multiple myeloma. As with other forms of radiation, the aim of 223Ra is to reduce tumor burden by directly killing tumor cells. External beam (photon) and proton radiation have been shown to augment tumor sensitivity to antigen-specific CD8+ cytotoxic T lymphocytes (CTLs). However, little is known about whether treatment with 223Ra can also induce such immunogenic modulation in tumor cells that survive irradiation. We examined these effects in vitro by exposing human prostate, breast, and lung carcinoma cells to sublethal doses of 223Ra. 223Ra significantly enhanced T cell-mediated lysis of each tumor type by CD8+ CTLs specific for MUC-1, brachyury, and CEA tumor antigens. Immunofluorescence analysis revealed that the increase in CTL killing was accompanied by augmented protein expression of MHC-I and calreticulin in each tumor type, molecules that are essential for efficient antigen presentation. Enhanced tumor-cell lysis was facilitated by calreticulin surface translocation following 223Ra exposure. The phenotypic changes observed after treatment appear to be mediated by induction of the endoplasmic reticulum stress response pathway. By rendering tumor cells more susceptible to T cell-mediated lysis, 223Ra may potentially be effective in combination with various immunotherapies, particularly cancer vaccines that are designed to generate and expand patients' endogenous antigen-specific T-cell populations against specific tumor antigens.

  1. Association of Cytotoxic T-Lymphocyte-Associated Protein 4 (CTLA4) Gene Polymorphisms with Autoimmune Thyroid Disease in Children and Adults: Case-Control Study (United States)

    Lo, Fu-Sung; Wang, Chao-Hung; Huang, Chi-Yu; Lin, Chiung-Ling; Lin, Wen-Shan; Chang, Tzu-Yang; Yang, Horng-Woei; Chen, Wei-Fang; Lien, Ya-Ping; Cheng, Bi-Wen; Lin, Chao-Hsu; Chen, Chia-Ching; Wu, Yi-Lei; Hung, Chen-Mei; Li, Hsin-Jung; Chan, Chon-In; Lee, Yann-Jinn


    Autoimmune thyroid disease (AITD), including Graves disease (GD) and Hashimoto disease (HD), is an organ-specific autoimmune disease with a strong genetic component. Although the cytotoxic T-lymphocyte-associated protein 4 (CTLA4) polymorphism has been reported to be associated with AITD in adults, few studies have focused on children. The aim of our study was to investigate whether the CTLA4 polymorphisms, including -318C/T (rs5742909), +49A/G (rs231775), and CT60 (rs3087243), were associated with GD and HD in Han Chinese adults and children. We studied 289 adult GD, 265 pediatric GD, 229 pediatric HD patients, and 1058 healthy controls and then compared genotype, allele, carrier, and haplotype frequencies between patients and controls. We found that CTLA4 SNPs +49A/G and CT60 were associated with GD in adults and children. Allele G of +49A/G was significantly associated with GD in adults (odds ratio [OR], 1.50; 95% confidence interval [CI], 1.21–1.84; corrected P value [Pc] < 0.001) and children (OR, 1.42; 95% CI, 1.15–1.77; Pc = 0.002). Allele G of CT60 also significantly increased risk of GD in adults (OR, 1.63; 95% CI, 1.27–2.09; Pc < 0.001) and GD in children (OR, 1.58; 95% CI, 1.22–2.04; Pc < 0.001). Significant linkage disequilibrium was found between +49A/G and CT60 in GD and control subjects (D’ = 0.92). Our results showed that CTLA4 was associated with both GD and HD and played an equivalent role in both adult and pediatric GD in Han Chinese population. PMID:27111218

  2. Association of Cytotoxic T-Lymphocyte-Associated Protein 4 (CTLA4 Gene Polymorphisms with Autoimmune Thyroid Disease in Children and Adults: Case-Control Study.

    Directory of Open Access Journals (Sweden)

    Wei-Hsin Ting

    Full Text Available Autoimmune thyroid disease (AITD, including Graves disease (GD and Hashimoto disease (HD, is an organ-specific autoimmune disease with a strong genetic component. Although the cytotoxic T-lymphocyte-associated protein 4 (CTLA4 polymorphism has been reported to be associated with AITD in adults, few studies have focused on children. The aim of our study was to investigate whether the CTLA4 polymorphisms, including -318C/T (rs5742909, +49A/G (rs231775, and CT60 (rs3087243, were associated with GD and HD in Han Chinese adults and children. We studied 289 adult GD, 265 pediatric GD, 229 pediatric HD patients, and 1058 healthy controls and then compared genotype, allele, carrier, and haplotype frequencies between patients and controls. We found that CTLA4 SNPs +49A/G and CT60 were associated with GD in adults and children. Allele G of +49A/G was significantly associated with GD in adults (odds ratio [OR], 1.50; 95% confidence interval [CI], 1.21-1.84; corrected P value [Pc] < 0.001 and children (OR, 1.42; 95% CI, 1.15-1.77; Pc = 0.002. Allele G of CT60 also significantly increased risk of GD in adults (OR, 1.63; 95% CI, 1.27-2.09; Pc < 0.001 and GD in children (OR, 1.58; 95% CI, 1.22-2.04; Pc < 0.001. Significant linkage disequilibrium was found between +49A/G and CT60 in GD and control subjects (D' = 0.92. Our results showed that CTLA4 was associated with both GD and HD and played an equivalent role in both adult and pediatric GD in Han Chinese population.

  3. Adoptive transfer of PR1 cytotoxic T lymphocytes associated with reduced leukemia burden in a mouse acute myeloid leukemia xenograft model. (United States)

    Ma, Qing; Wang, Changqing; Jones, Dan; Quintanilla, Kathryn E; Li, Dan; Wang, Yang; Wieder, Eric D; Clise-Dwyer, Karen; Alatrash, Gheath; Mj, You; Munsell, Mark F; Lu, Sijie; Qazilbash, Muzaffar H; Molldrem, Jeffrey J


    Tumor antigen-specific cytotoxic T lymphocytes (CTL) have been used in the treatment of human cancer, including leukemia. Several studies have established PR1 peptide, an HLA-A2.1-restricted peptide derived from proteinase 3 (P3), as a human leukemia-associated antigen. PR1-specific CTL elicited in vitro from healthy donors have been shown to lyse P3-expressing AML cells from patients. We investigated whether PR1-CTL can be adoptively transferred into NOD/SCID mice to eliminate human leukemia cells. PR1-CTL were generated in bulk culture from peripheral blood mononuclear cells (PBMC) stimulated with autologous dendritic cells. Human acute myeloid leukemia (AML) patient samples were injected and engrafted in murine bone marrow at 2 weeks post-transfer. Following adoptive transfer, bone marrow aspirate from mice that received AML alone had 72-88% blasts in a hypercellular marrow, whereas mice that received AML plus PR1-CTL co-infusion had normal hematopoietic elements and only 3-18% blasts in a hypocellular marrow. The PR1-CTL persisted in the bone marrow and liver and maintained a CD45RA⁻CD28+ effector phenotype. We found that adoptive transfer of PR1-CTL generated in vitro is associated with reduced AML cells in NOD/SCID mice. PR1-CTL can migrate to the sites of disease and maintain their capacity to kill the AML cells. The surface phenotype of PR1-CTL was consistent with their trafficking pattern in both vascular and end-organ tissues.

  4. In vitro priming of tumor-specific cytotoxic T lymphocytes using allogeneic dendritic cells derived from the human MUTZ-3 cell line. (United States)

    Santegoets, Saskia J A M; Schreurs, Marco W J; Masterson, Allan J; Liu, Ying Poi; Goletz, Steffen; Baumeister, Hans; Kueter, Esther W M; Lougheed, Sinéad M; van den Eertwegh, Alfons J M; Scheper, Rik J; Hooijberg, Erik; de Gruijl, Tanja D


    The adoptive transfer of in vitro-induced and expanded tumor-specific cytotoxic T lymphocytes (CTL) presents a promising immunotherapeutic approach for the treatment of cancer. The in vitro induction of tumor-reactive CTL requires repeated stimulation of CTL precursors with dendritic cells (DC). To circumvent problems like scarcity of blood DC precursors and donor variability, it would be attractive to use DC from a non-autologous, unlimited source. DCs derived from the human acute myeloid leukemia (AML) cell line MUTZ-3 are attractive candidates since these DCs closely resemble monocyte-derived DC (MoDC) in terms of phenotype and T cell stimulatory capacity. Here we demonstrate that functional CTL clones could be generated against multiple tumor-associated antigens, i.e., human telomerase reverse transcriptase (hTERT), ErbB3-binding protein-1 (Ebp1), carcinoembryonic antigen (CEA) and Her-2/neu, by stimulating CD8beta(+) CTL precursors with peptide-loaded allogeneic, HLA-A2-matched MUTZ-3-derived DC. A consistent induction capacity, as determined by MHC tetramer-binding, was found in multiple donors and comparable to autologous peptide-loaded MoDC. Functional characterization at the clonal level revealed the priming of CTL that recognized endogenously processed epitopes on tumor cell lines in an HLA-A2-restricted fashion. Our data indicate that MUTZ-3-derived DC can be used as stimulator cells for in vitro priming and expansion of functional TAA-specific effector CTL. MUTZ-3-derived DCs thus represent a ready and standardized source of allogeneic DC to generate CTL for therapeutic adoptive transfer strategies.

  5. Gag Protein Epitopes Recognized by ELA-A-Restricted Cytotoxic T Lymphocytes from Horses with Long-Term Equine Infectious Anemia Virus Infection (United States)

    Zhang, Wei; Lonning, Scott M.; McGuire, Travis C.


    Most equine infectious anemia virus (EIAV)-infected horses have acute clinical disease, but they eventually control the disease and become lifelong carriers. Cytotoxic T lymphocytes (CTL) are considered an important immune component in the control of infections with lentiviruses including EIAV, but definitive evidence for CTL in the control of disease in carrier horses is lacking. By using retroviral vector-transduced target cells expressing different Gag proteins and overlapping synthetic peptides of 16 to 25 amino acids, peptides containing at least 12 Gag CTL epitopes recognized by virus-stimulated PBMC from six long-term EIAV-infected horses were identified. All identified peptides were located within Gag matrix (p15) and capsid (p26) proteins, as no killing of target cells expressing p11 and p9 occurred. Each of the six horses had CTL recognizing at least one Gag epitope, while CTL from one horse recognized at least eight different Gag epitopes. None of the identified peptides were recognized by CTL from all six horses. Two nonamer peptide epitopes were defined from Gag p26; one (18a) was likely restricted by class I equine leukocyte alloantigen A5.1 (ELA-A5.1) molecules, and the other (28b-1) was likely restricted by ELA-A9 molecules. Sensitization of equine kidney target cells for CTLm killing required 10 nM peptide 18a and 1 nM 28b-1. The results demonstrated that diverse CTL responses against Gag epitopes were generated in long-term EIAV-infected horses and indicated that ELA-A class I molecules were responsible for the diversity of CTL epitopes recognized. This information indicates that multiple epitopes or whole proteins will be needed to induce CTL in horses with different ELA-A alleles in order to evaluate their role in controlling EIAV. PMID:9811694

  6. Major Histocompatibility Complex-Dependent Cytotoxic T Lymphocyte Repertoire and Functional Avidity Contribute to Strain-Specific Disease Susceptibility after Murine Respiratory Syncytial Virus Infection ▿ (United States)

    Jessen, Birthe; Faller, Simone; Krempl, Christine D.; Ehl, Stephan


    Susceptibility to respiratory syncytial virus (RSV) infection in mice is genetically determined. While RSV causes little pathology in C57BL/6 mice, pulmonary inflammation and weight loss occur in BALB/c mice. Using major histocompatibility complex (MHC)-congenic mice, we observed that the H-2d allele can partially transfer disease susceptibility to C57BL/6 mice. This was not explained by altered viral elimination or differences in the magnitude of the overall virus-specific cytotoxic T lymphocyte (CTL) response. However, H-2d mice showed a more focused response, with 70% of virus-specific CTL representing Vβ8.2+ CTL directed against the immunodominant epitope M2-1 82, while in H-2b mice only 20% of antiviral CTL were Vβ9+ CTL specific for the immunodominant epitope M187. The immunodominant H-2d-restricted CTL lysed target cells less efficiently than the immunodominant H-2b CTL, probably contributing to prolonged CTL stimulation and cytokine-mediated immunopathology. Accordingly, reduction of dominance of the M2-1 82-specific CTL population by introduction of an M187 response in the F1 generation of a C57BL/6N × C57BL/6-H-2d mating (C57BL/6-H-2dxb mice) attenuated disease. Moreover, disease in H-2d mice was less pronounced after infection with an RSV mutant failing to activate M2-1 82-specific CTL or after depletion of Vβ8.2+ cells. These data illustrate how the MHC-determined diversity and functional avidity of CTL responses contribute to disease susceptibility after viral infection. PMID:21795345

  7. Adeno-associated virus type 2 (AAV2) capsid-specific cytotoxic T lymphocytes eliminate only vector-transduced cells coexpressing the AAV2 capsid in vivo. (United States)

    Li, Chengwen; Hirsch, Matthew; Asokan, Aravind; Zeithaml, Brian; Ma, Hong; Kafri, Tal; Samulski, R Jude


    A recent clinical trial has suggested that recombinant adeno-associated virus (rAAV) vector transduction in humans induces a cytotoxic T-lymphocyte (CTL) response against the AAV2 capsid. To directly address the ability of AAV capsid-specific CTLs to eliminate rAAV-transduced cells in vitro and in vivo in mice, we first demonstrated that AAV2 capsid-specific CTLs could be induced by dendritic cells with endogenous AAV2 capsid expression or pulsed with AAV2 vectors. These CTLs were able to kill a cell line stable for capsid expression in vitro and also in a mouse tumor xenograft model in vivo. Parent colon carcinoma (CT26) cells transduced with a large amount of AAV2 vectors in vitro were also destroyed by these CTLs. To determine the effect of CTLs on the elimination of target cells transduced by AAV2 vectors in vivo, we carried out adoptive transfer experiments. CTLs eliminated liver cells with endogenous AAV2 capsid expression but not liver cells transduced by AAV2 vectors, regardless of the reporter genes. Similar results were obtained for rAAV2 transduction in muscle. Our data strongly suggest that AAV vector-transduced cells are rarely eliminated by AAV2 capsid-specific CTLs in vivo, even though the AAV capsid can induce a CTL response. In conclusion, AAV capsid-specific CTLs do not appear to play a role in elimination of rAAV-transduced cells in a mouse model. In addition, our data suggest that the mouse model may not mimic the immune response noted in humans and additional modification to AAV vectors may be required for further study in order to elicit a similar cellular immune response.

  8. Adeno-Associated Virus Type 2 (AAV2) Capsid-Specific Cytotoxic T Lymphocytes Eliminate Only Vector-Transduced Cells Coexpressing the AAV2 Capsid In Vivo▿ (United States)

    Li, Chengwen; Hirsch, Matthew; Asokan, Aravind; Zeithaml, Brian; Ma, Hong; Kafri, Tal; Samulski, R. Jude


    A recent clinical trial has suggested that recombinant adeno-associated virus (rAAV) vector transduction in humans induces a cytotoxic T-lymphocyte (CTL) response against the AAV2 capsid. To directly address the ability of AAV capsid-specific CTLs to eliminate rAAV-transduced cells in vitro and in vivo in mice, we first demonstrated that AAV2 capsid-specific CTLs could be induced by dendritic cells with endogenous AAV2 capsid expression or pulsed with AAV2 vectors. These CTLs were able to kill a cell line stable for capsid expression in vitro and also in a mouse tumor xenograft model in vivo. Parent colon carcinoma (CT26) cells transduced with a large amount of AAV2 vectors in vitro were also destroyed by these CTLs. To determine the effect of CTLs on the elimination of target cells transduced by AAV2 vectors in vivo, we carried out adoptive transfer experiments. CTLs eliminated liver cells with endogenous AAV2 capsid expression but not liver cells transduced by AAV2 vectors, regardless of the reporter genes. Similar results were obtained for rAAV2 transduction in muscle. Our data strongly suggest that AAV vector-transduced cells are rarely eliminated by AAV2 capsid-specific CTLs in vivo, even though the AAV capsid can induce a CTL response. In conclusion, AAV capsid-specific CTLs do not appear to play a role in elimination of rAAV-transduced cells in a mouse model. In addition, our data suggest that the mouse model may not mimic the immune response noted in humans and additional modification to AAV vectors may be required for further study in order to elicit a similar cellular immune response. PMID:17475652

  9. Cytotoxic-T-lymphocyte-mediated elimination of target cells transduced with engineered adeno-associated virus type 2 vector in vivo. (United States)

    Li, Chengwen; Hirsch, Matt; DiPrimio, Nina; Asokan, Aravind; Goudy, Kevin; Tisch, Roland; Samulski, R Jude


    A recent clinical trial in patients with hemophilia B has suggested that adeno-associated virus (AAV) capsid-specific cytotoxic T lymphocytes (CTLs) eliminated AAV-transduced hepatocytes and resulted in therapeutic failure. AAV capsids elicit a CTL response in animal models; however, these capsid-specific CTLs fail to kill AAV-transduced target cells in mice. To better model the human clinical trial data in mice, we introduced an immunodominant epitope derived from ovalbumin (OVA; SIINFEKL) into the AAV capsid and tested CTL-mediated killing of AAV2-transduced target tissues in vivo. Initially, in vitro experiments demonstrated both classical class I and cross-presentation of the OVA antigen, following endogenous expression or AAV2-OVA vector transduction, respectively. Furthermore, an OVA-specific CTL response was elicited after muscular or systemic injection of the AAV2-OVA vector. Finally, CTL reactivity was enhanced in mice with established SIINFEKL-specific immunity after AAV2-OVA/alpha1 anti-trypsin (AAT) administration. Most importantly, these OVA-specific CTLs decreased AAT expression in mice treated with AAV2-OVA/AAT vector that followed a time course mimicking uncoating kinetics of AAV2 transduction in OVA-immunized mice. These results demonstrate that AAV capsid-derived antigens elicit CD8(+) CTL reactivity, and these CTLs eliminated AAV-transduced target cells in mice. Notably, this model system can be exploited to study the kinetics of capsid presentation from different serotypes of AAV and permit the design of novel strategies to block CTL-mediated killing of AAV-transduced cells.

  10. Iron oxide nanoparticles show no toxicity in the comet assay in lymphocytes: A promising vehicle as a nitric oxide releasing nanocarrier in biomedical applications (United States)

    de Lima, R.; Oliveira, J. L.; Murakami, P. S. K.; Molina, M. A. M.; Itri, R.; Haddad, P.; Seabra, A. B.


    This work reports the synthesis and toxicological evaluation of surface modified magnetic iron oxide nanoparticles as vehicles to carry and deliver nitric oxide (NO). The surface of the magnetic nanoparticles (MNPs) was coated with two thiol-containing hydrophilic ligands: mercaptosuccinic acid (MSA) or dimercaptosuccinic acid (DMSA), leading to thiolated MNPs. Free thiols groups on the surface of MSA- or DMSA-MNPs were nitrosated leading to NO-releasing MNPs. The genotoxicity of thiolated-coated MNPs was evaluated towards human lymphocyte cells by the comet assay. No genotoxicity was observed due to exposure of human lymphocytes to MSA- or DMSA-MNPs, indicating that these nanovectors can be used as inert vehicles in drug delivery, in biomedical applications. On the other hand, NO-releasing MPNs showed genotoxicity and apoptotic activities towards human lymphocyte cell cultures. These results indicate that NO-releasing MNPs may result in important biomedical applications, such as the treatment of tumors, in which MNPs can be guided to the target site through the application of an external magnetic field, and release NO directly to the desired site of action.

  11. Use of “one-pot, mix-and-read” peptide-MHC class I tetramers and predictive algorithms to improve detection of cytotoxic T lymphocyte responses in cattle (United States)


    Peptide-major histocompatibility complex (p-MHC) class I tetramer complexes have facilitated the early detection and functional characterisation of epitope specific CD8+ cytotoxic T lymphocytes (CTL). Here, we report on the generation of seven recombinant bovine leukocyte antigens (BoLA) and recombinant bovine β2-microglobulin from which p-MHC class I tetramers can be derived in ~48 h. We validated a set of p-MHC class I tetramers against a panel of CTL lines specific to seven epitopes on five different antigens of Theileria parva, a protozoan pathogen causing the lethal bovine disease East Coast fever. One of the p-MHC class I tetramers was tested in ex vivo assays and we detected T. parva specific CTL in peripheral blood of cattle at day 15-17 post-immunization with a live parasite vaccine. The algorithm NetMHCpan predicted alternative epitope sequences for some of the T. parva CTL epitopes. Using an ELISA assay to measure peptide-BoLA monomer formation and p-MHC class I tetramers of new specificity, we demonstrate that a predicted alternative epitope Tp229-37 rather than the previously reported Tp227-37 epitope is the correct Tp2 epitope presented by BoLA-6*04101. We also verified the prediction by NetMHCpan that the Tp587-95 epitope reported as BoLA-T5 restricted can also be presented by BoLA-1*02301, a molecule similar in sequence to BoLA-T5. In addition, Tp587-95 specific bovine CTL were simultaneously stained by Tp5-BoLA-1*02301 and Tp5-BoLA-T5 tetramers suggesting that one T cell receptor can bind to two different BoLA MHC class I molecules presenting the Tp587-95 epitope and that these BoLA molecules fall into a single functional supertype. PMID:24775445

  12. Thaw-and-use target cells pre-labeled with calcein AM for antibody-dependent cell-mediated cytotoxicity assays. (United States)

    Chung, Shan; Nguyen, Van; Lin, Yuwen Linda; Kamen, Lynn; Song, An


    In vitro antibody-dependent cell-mediated cytotoxicity (ADCC) assays are routinely performed to support the research and development of therapeutic antibodies. In ADCC assays, target cells bound by the antibodies are lysed by activated effector cells following interactions between the Fc region of the bound antibody and Fcγ receptors on effector cells. Target cell lysis is typically measured by quantification of released endogenous enzymes, e.g., lactate dehydrogenase, or measurement of released exogenous labels, e.g., (51)Cr, europium or calcein. ADCC assays based on the detection of exogenous labels released from lysed target cells generally show higher sensitivity and require shorter incubation times. However, target cells are usually labeled immediately prior to assay, which inadvertently introduces additional assay variations due to differences in target cell conditions and labeling/handling processes. In this report, we describe the use of thaw-and-use pre-labeled target cells for ADCC assays. Thaw-and-use target cells in our experiments were pre-labeled with the fluorescent dye calcein AM, cryopreserved in single-use aliquots and used directly in assays after thawing. Upon thaw, the pre-labeled cells displayed viability and label retention comparable to freshly labeled cells, responded to ADCC mediated by both peripheral blood mononuclear cells and engineered natural killer cells, performed stably for at least 3 years and provided favorable precision and accuracy to ADCC assays. Implementation of thaw-and-use pre-labeled target cells in ADCC assays can help to alleviate both cell culture and dye labeling derived variability, increase the flexibility of assay scheduling and improve assay consistency and robustness. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. In Vitro genotoxic and antigenotoxic studies of Thai Noni fruit juice by chromosomal aberration and sister chromatid exchange assays in human lymphocytes

    Directory of Open Access Journals (Sweden)

    Treetip Ratanavalachai


    Full Text Available The genotoxic and antigenotoxic effects of Noni fruit juice produced in Thailand have been studied in human lymphocytes for chromosome aberration assay and sister chromatid exchange (SCE assay in vitro. Treatment of Noni fruit juice(3.1-50 mg/ml alone for 3 h did not significantly induce chromosomal aberration or SCE (p<0.05. Noni fruit juice at 6.2 mg/ml is the optimum dose for cell survival and cell replication as demonstrated by the highest value of mitotic index and proliferation index (P.I.. Interestingly, pretreatment of Noni fruit juice at the same concentration of 6.2 mg/ml for 2 hfollowed by mitomycin C treatment at 3 μg/ml for 2 h significantly reduced SCE level induced by mitomycin C (p<0.05. However, these treatments did not show significant decrease in chromatid-type aberrations. Our data indicate that Thai Noni fruit juice is not genotoxic against human lymphocytes in vitro. In addition, pretreatment of Noni fruit juice at 6.2 mg/ml demonstrated no anticlastogenic effect while had some antigenotoxic effects as demonstrated by significant decrease in the SCE level induced by mitomycin C (p<0.05. Therefore, the optimum dose of Noni fruit juice used as a traditional medicine is required and needs to be studied further for the benefit of human health.

  14. Genotoxicity assessment of antidiabetic formulation (ADPHF6 in human lymphocytes by single cell gel electrophoresis (comet assay - an in vitro study

    Directory of Open Access Journals (Sweden)

    Devanand Shanmugasundaram


    Full Text Available Levels of Reactive Oxygen Species (ROS molecules during aerobic metabolism are often regulated by unique endogenous antioxidant system. During hyperglycaemic condition, accumulation of excess fatty acids & glucose in adipose tissue (Wright Jr E., 2006 results in increased levels of ROS. When ROS molecules overwhelms the cells antioxidant defence system, it ends up in cellular oxidative stress; which in turn is reported to cause oxidative DNA damage & intervene damage to macromolecules & cellular membranes (Ahmad et al., 2013. Our novel anti-hyperglycaemic polyherbal formulation (ADPHF6 had already illustrated significant inhibitory activity against α-amylase & α-glucosidase enzymes and also scavenging free radicals (in vitro models. The present study demonstrates the protective effect of formulation against H2O2 induced DNA damage in human lymphocytes by Single Cell Gel Electrophoresis (SCGE assay. Experimental procedures were approved by Institutional Human Ethics Committee of Frontier Lifeline Hospital, Chennai, India (FLL/IEC/02/2014. Peripheral human lymphocytes were isolated (Duthie, 2002 and subjected for Cell viability by Trypan blue exclusion method. The alkaline SCGE assay was carried out to determine the level of DNA damage in ADPHF6 treated cells with minor modifications from Singh et al., 1988. Frosted microscopic slides were pre-coated with 1% NMA followed by 1% LMA and incubated for 15 min at 15-20o C. 100 μL of freshly prepared cell suspension (2 x 104 cells was mixed with 0.5% LMA & casted on microscopic slide. The cells were immersed in lysing solution for 2 hours at 4O C and washed in TBE buffer for 5 min at RT. All the slides were treated with fresh alkaline solution for 20 minutes for expression of alkali-labile damage. Electrophoresis was performed at 24 V for 20 min at RT. Slides were washed in neutralizing buffer for 5 min at RT. All the groups were stained with Acridine Orange (20µg/ml & Propidium Iodide (20µg

  15. Determining the size and concentration dependence of gold nanoparticles in vitro cytotoxicity (IC{sub 50}) test using WST-1 assay

    Energy Technology Data Exchange (ETDEWEB)

    Rosli, Nur Shafawati binti; Rahman, Azhar Abdul [School of Physics, Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); Aziz, Azlan Abdul [School of Physics, Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); Shamsuddin, Shaharum [Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); School of Health Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)


    Gold nanoparticles (AuNPs) received a great deal of attention for biomedical applications, especially in diagnostic imaging and therapeutics. Even though AuNPs have potential benefits in biomedical applications, the impact of AuNPs on human and environmental health still remains unclear. The use of AuNPs which is a high-atomic-number materials, provide advantages in terms of radiation dose enhancement. However, before this can become a clinical reality, cytotoxicity of the AuNPs has to be carefully evaluated. Cytotoxicity test is a rapid, standardized test that is very sensitive to determine whether the nanoparticles produced are harmful or benign on cellular components. In this work the size and concentration dependence of AuNPs cytotoxicity in breast cancer cell lines (MCF-7) are tested by using WST-1 assay. The sizes of AuNPs tested were 13 nm, 50 nm, and 70 nm. The cells were seeded in the 96-well plate and were treated with different concentrations of AuNPs by serial dilution for each size of AuNPs. The high concentration of AuNPs exhibit lower cell viability compared to low concentration of AuNPs. We quantified the toxicity of AuNPs in MCF-7 cell lines by determining the IC{sub 50} values in WST-1 assays. The IC{sub 50} values (inhibitory concentrations that effected 50% growth inhibition) of 50 nm AuNPs is lower than 13 nm and 70 nm AuNPs. Mean that, 50nm AuNPs are more toxic to the MCF-7 cells compared to smaller and larger sizes AuNPs. The presented results clearly indicate that the cytotoxicity of AuNPs depend not only on the concentration, but also the size of the nanoparticles.

  16. Regulatory B cells inhibit cytotoxic T lymphocyte (CTL activity and elimination of infected CD4 T cells after in vitro reactivation of HIV latent reservoirs.

    Directory of Open Access Journals (Sweden)

    Basile Siewe

    Full Text Available During HIV infection, IL-10/IL-10 receptor and programmed death-1 (PD-1/programmed death-1-ligand (PD-L1 interactions have been implicated in the impairment of cytotoxic T lymphocyte (CTL activity. Despite antiretroviral therapy (ART, attenuated anti-HIV CTL functions present a major hurdle towards curative measures requiring viral eradication. Therefore, deeper understanding of the mechanisms underlying impaired CTL is crucial before HIV viral eradication is viable. The generation of robust CTL activity necessitates interactions between antigen-presenting cells (APC, CD4+ and CD8+ T cells. We have shown that in vitro, IL-10hiPD-L1hi regulatory B cells (Bregs directly attenuate HIV-specific CD8+-mediated CTL activity. Bregs also modulate APC and CD4+ T cell function; herein we characterize the Breg compartment in uninfected (HIVNEG, HIV-infected "elite controllers" (HIVEC, ART-treated (HIVART, and viremic (HIVvir, subjects, and in vitro, assess the impact of Bregs on anti-HIV CTL generation and activity after reactivation of HIV latent reservoirs using suberoylanilide hydroxamic acid (SAHA. We find that Bregs from HIVEC and HIVART subjects exhibit comparable IL-10 expression levels significantly higher than HIVNEG subjects, but significantly lower than HIVVIR subjects. Bregs from HIVEC and HIVART subjects exhibit comparable PD-L1 expression, significantly higher than in HIVVIR and HIVNEG subjects. SAHA-treated Breg-depleted PBMC from HIVEC and HIVART subjects, displayed enhanced CD4+ T-cell proliferation, significant upregulation of antigen-presentation molecules, increased frequency of CD107a+ and HIV-specific CD8+ T cells, associated with efficient elimination of infected CD4+ T cells, and reduction in integrated viral DNA. Finally, IL-10-R and PD-1 antibody blockade partially reversed Breg-mediated inhibition of CD4+ T-cell proliferation. Our data suggest that, possibly, via an IL-10 and PD-L1 synergistic mechanism; Bregs likely inhibit APC

  17. Combined fluorimetric caspase 3/7 assay and bradford protein determination for assessment of polycation-mediated cytotoxicity

    DEFF Research Database (Denmark)

    Larsen, Anna K; Hall, Arnaldur; Lundsgart, Henrik


    and design of safe and efficient nucleic acid delivery systems. Numerous methods are presently available to detect and delineate cytotoxicity and cell death-mediated signals in cell cultures. Activation of caspases is part of the classical apoptosis program and increased caspase activity is therefore a well...

  18. Comparison of differences between dicentric assay and translocation analysis for biodosimetry in cultured peripheral blood lymphocytes of Korean individuals

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyun Jin; Park, Mi Young; Seo, Min Ji; Kwon, Hee Kyung; Lee, Su Jae; Lee, Yun Sil; Ji, Young Hoon; Choi, Soo Yong; Cho, Chul Koo; Kim, Tae Hwan; Kang, Chang Mo [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)


    Chromosome aberrations are considered to be important indicators of induced DNA damage and genomic instability. For this reason, they constitute the main parameter used to monitor individuals exposed to radiation. Biological dosimetry using the analysis of dicentrics in human lymphocytes is well established, especially in case of acute exposure, when the blood samples are taken within a few weeks. However, dicentric analysis is not an adequate parameter in case of chronic exposure, because these aberrations are unstable with time, and have a limited use for dose assessment of past exposures. In contrast to dicentrics, however, translocations are considered stable in cell division and so the yield should not fall with time. In the present study, using FISH-chromosome painting analysis with the dose-response curve for chromosome aberrations, we monitored the stable and unstable chromosome aberrations of 2 Korean's periperal blood lymphocytes irradiated in vitro with {gamma}-rays from {sup 137}Cs (doses between 0.0 and 2.0 Gy). By using the dose-response curve for chromosome aberration, our aim was to estimate the absorbed doses, and then establish comparison with the results obtained by conventional dicentric analysis, thus taking the opportunity to test the validity of chromosome aberration analysis by FISH painting method for retrospective biodosimetry in Korean individual.

  19. Assessment of the DNA Damage in Human Sperm and Lymphocytes Exposed to the Carcinogen Food Contaminant Furan with Comet Assay

    Directory of Open Access Journals (Sweden)

    Dilek Pandir


    Full Text Available ABSTRACTThe aim of this work was to assess the damage of DNA in human blood cell and spermin vitro under the influence of furan. These cells were administered 0-600 μM of furan at 37 and 32oC for 30 and 60 min, respectively. A significant increase in tail DNA%, tail length and moment indicating DNA damage was observed at increasing doses when compared to the controls. The treatment with 300 and 600 μM of furan showed a maximum increase of 86.74 ± 2.43 and 93.29 ± 8.68 compared to the control tail DNA% in lymphocytes. However, only 600 μM of furan showed a maximum increase of 94.71 ± 6.24 compared to the control tail DNA% in sperm. The results suggested that furan caused DNA damage in lymphocytes at increasing doses, but appeared to have not the same effect on human sperm at the low doses. Genotoxic activity had an impact on the risk assessment of furan formed on the food for human cells. Therefore, it would be important to further investigate these properties of furan as the food mutagen.

  20. The cytotoxic activity of cisplatin, carboplatin and teniposide alone and combined determined on four human small cell lung cancer cell lines by the clonogenic assay

    DEFF Research Database (Denmark)

    Roed, H; Vindeløv, L L; Christensen, I J


    culture medium. By combining either cisplatin or carboplatin with teniposide additive cell kill was obtained. Additivity was also obtained when cisplatin was combined with carboplatin. Since the two drugs have a different toxicity pattern a clinical synergy may be obtained by combined use of these two......Using the clonogenic assay to compare the cytotoxic activity of cisplatin and carboplatin on four human small cell lung cancer cell lines, cisplatin was shown to be equally or more potent than carboplatin at equitoxic doses with 1 h incubation. Increased potency of carboplatin was revealed when...

  1. The cytotoxic activity of cisplatin, carboplatin and teniposide alone and combined determined on four human small cell lung cancer cell lines by the clonogenic assay

    DEFF Research Database (Denmark)

    Roed, H; Vindeløv, L L; Christensen, I J


    Using the clonogenic assay to compare the cytotoxic activity of cisplatin and carboplatin on four human small cell lung cancer cell lines, cisplatin was shown to be equally or more potent than carboplatin at equitoxic doses with 1 h incubation. Increased potency of carboplatin was revealed when...... the drugs were tested with continuous incubation, although cisplatin still was the most potent drug when compared on a microgram to microgram basis. This relative increase in potency of carboplatin can at least partly be explained by the development of a more reactive form of the drug when stored in tissue...

  2. Evaluation of the absorption of methotrexate on cells and its cytotoxicity assay by using an integrated microfluidic device coupled to a mass spectrometer. (United States)

    Gao, Dan; Li, Haifang; Wang, Niejun; Lin, Jin-Ming


    An integrated microfluidic device was developed for high-throughput drug screening with an online electrospray ionization quadrupole time-of-flight mass spectrometer (ESI-Q-TOF MS). The multiple gradient generator followed by an array of microscale cell culture chambers and on-chip solid-phase extraction (SPE) columns for sample pretreatment prior to mass analysis was integrated in the device which was fabricated in one single step. By using the combination system, the process for characterization of drug absorption and evaluation of cytotoxicity could be simultaneously realized. To validate the feasibility, the absorption of methotrexate and its effects on HepG2 and Caco-2 cells were investigated. With the increasing concentration of drugs, the percentage of apoptotic cells appeared in a dose-dependent fashion. By comparison with the results obtained from ESI-Q-TOF MS analysis and cytotoxicity assay, we found that higher intracellular drug concentration resulted in increased cell cytotoxicity. The technique presented herein provides an easy protocol to screen drugs rapidly with low drug consumption, high throughput, and high sensitivity.

  3. Xanthium strumarium L. Extracts Produce DNA Damage Mediated by Cytotoxicity in In Vitro Assays but Does Not Induce Micronucleus in Mice (United States)

    Piloto Ferrer, Janet; Cozzi, Renata; Cornetta, Tommaso; Stano, Pasquale; Fiore, Mario; Degrassi, Francesca; De Salvia, Rosella; Remigio, Antonia; Francisco, Marbelis; Quiñones, Olga; Valdivia, Dayana; González, Maria L.; Pérez, Carlos; Sánchez-Lamar, Angel


    Xanthium strumarium L. is a member of the Asteraceae commonly used in Cuba, mainly as diuretic. Some toxic properties of this plant have also been reported and, to date, very little is known about its genotoxic properties. The present work aims was to evaluate the potential cytotoxic and genotoxic risk of whole extract from Xanthium strumarium L. whole extract of aerial parts. No positive response was observed in a battery of four Salmonella typhimurium strains, when exposed to concentrations up to 5 mg/plate, with and without mammalian metabolic activation (liver microsomal S9 fraction from Wistar rats). In CHO cells, high concentrations (25–100 μg/mL) revealed significant reduction in cell viability. Results from sister chromatid exchanges, chromosome aberrations, and comet assay showed that X. strumarium extract is genotoxic at the highest concentration used, when clear cytotoxic effects were also observed. On the contrary, no increase in micronuclei frequency in bone marrow cells was observed when the extract was orally administered to mice (100, 500, and 2000 mg/Kg doses). The data presented here constitute the most complete study on the genotoxic potential of X. strumarium L. and show that the extract can induce in vitro DNA damage at cytotoxic concentrations. PMID:25025061

  4. Xanthium strumarium L. Extracts Produce DNA Damage Mediated by Cytotoxicity in In Vitro Assays but Does Not Induce Micronucleus in Mice

    Directory of Open Access Journals (Sweden)

    Janet Piloto Ferrer


    Full Text Available Xanthium strumarium L. is a member of the Asteraceae commonly used in Cuba, mainly as diuretic. Some toxic properties of this plant have also been reported and, to date, very little is known about its genotoxic properties. The present work aims was to evaluate the potential cytotoxic and genotoxic risk of whole extract from Xanthium strumarium L. whole extract of aerial parts. No positive response was observed in a battery of four Salmonella typhimurium strains, when exposed to concentrations up to 5 mg/plate, with and without mammalian metabolic activation (liver microsomal S9 fraction from Wistar rats. In CHO cells, high concentrations (25–100 μg/mL revealed significant reduction in cell viability. Results from sister chromatid exchanges, chromosome aberrations, and comet assay showed that X. strumarium extract is genotoxic at the highest concentration used, when clear cytotoxic effects were also observed. On the contrary, no increase in micronuclei frequency in bone marrow cells was observed when the extract was orally administered to mice (100, 500, and 2000 mg/Kg doses. The data presented here constitute the most complete study on the genotoxic potential of X. strumarium L. and show that the extract can induce in vitro DNA damage at cytotoxic concentrations.

  5. Standardisation and quality assurance of lymphocyte proliferation assays for use in the assessment of immune function. European Concerted Action on Immunological and Virological Markers of HIV Disease Progression. (United States)

    Froebel, K S; Pakker, N G; Aiuti, F; Bofill, M; Choremi-Papadopoulou, H; Economidou, J; Rabian, C; Roos, M T; Ryder, L P; Miedema, F; Raab, G M


    Lymphocyte proliferation is a widely used technique to assess immune competence. However, the technique is subject to a large degree of variation, some biological and some technical. In this study, the components of variation in whole blood proliferation assays were analysed over time, using both antibody and mitogenic stimulants. The levels of variation within individual samples, between individuals and between groups of individuals over time were examined. A method of transforming the data is proposed which reduces the coefficients of variation to an acceptable level, and which expresses individual results as a standardised count. This method overcomes the problem of different levels of absolute counts, it corrects for time sensitive errors and allows data from multiple laboratories to be pooled.

  6. Cytotoxicity and Inhibition of Lymphocyte Proliferation of Fasciculatin, a Linear Furanosesterterpene Isolated from Ircinia variabilis Collected from the Atlantic Coast of Morocco


    Werner Herz; Maria São José Nascimento; Nair Nazareth; Anake Kijjoa; Pinho, Paulo M.; Aziz Fassouane; Saida Rifai


    Abstract: Fasciculatin, a furanosesterterpene isolated from the marine sponge Ircinia variabilis from the Atlantic Coast of Morocco, has been evaluated for its influence on a mitogen-induced proliferation of human lymphocytes and growth of human tumor cell lines.

  7. Cytotoxic evaluation of medicinal smoke \\"Anbar Nasara\\" against cancer cells (Hela & KB and a normal cell line (L929, using MTT assay

    Directory of Open Access Journals (Sweden)

    hojat Sadeghi-aliabadi


    Full Text Available Background: Medicinal smoke has been in natural health products by many nations all over the worlds. Dung's smoke called "Anbar Nasara" is one of the most used medicinal smokes in Iranian traditional medicine. Anber Nasara has been administered as inhalation in the treatment of viral or bacterial infections as well as for tumors and cysts in vaginal diseases in women. Its cytotoxic effects have been proposed in these studies. Materials and Methods: Dung's of female donkey have been collected from Shahreza, Isfahan province in summer 2011. The samples were burned in a specially designed apparatus and its smoke was collected in n-hexane solvent over ice-cold water. Solvent was evaporated in the air and dried residue was dissolved in DMSO and diluted in RPMI So that the final concentrations of 0.4, 0.3, 0.25, 0.2, 0.125, 0.1, 0.0625, 0.0312 mg/ml were obtained for MTT assay as a cytotoxic evaluation method against two cancer cells (KB and Hela and a normal one (L929. After 48h incubation percent cell survival and IC50 values were obtained using ELISA plate reader at 540nm. Results: Results showed that dung's smoke were cytotoxic in tested concentrations against cancer cell lines in a dose dependent manner. The IC50 was calculated ≥ 0.2 mg/ml. Conclusion: Dung's smoke consists of too many constituents and its cytotoxic effect may belong to one or complexes of constituents. More researches are under way to clarify these aspects of the study.

  8. The sensitivity of the in vitro cytokinesis-blocked micronucleus assay in lymphocytes for different and combined radiation qualities

    Energy Technology Data Exchange (ETDEWEB)

    Wuttke, K.; Mueller, W.U.; Streffer, C. [Universitaetsklinikum Essen (Germany). Inst. fuer Medizinische Strahlenbiologie


    Purpose: The dose-response relationship and the relative biological effectiveness (RBE) for the induction of micronuclei in lymphocytes was analyzed after irradiation in vitro with a 6-MeV neutron beam that was followed by 240-kV X-rays. The dose range of the combined exposure comprised 1 to 3 Gy. For reference, the dose-effect relationships found after X-ray (0.5 to 5 Gy)- and neutron (0.5 to 4 Gy) exposure applied separately are presented. The possibility of an interaction between the 2 radiation qualities is investigated by the method of isobole calculation termed `envelope of additivity`. Methods: Micronuclei were analyzed in PHA-stimulated, cytokinesis-blocked human lymphocytes. Results: The dose-response relationships for the micronucleus frequencies induced by the neutron irradiation, as well as by the mixed exposure, were linear. A saturation effect was indicated after neutron doses higher than 3 Gy. After low LET exposure the dose-response curves were describable by a linear-quadratic model. For neutron-induced micronucleus frequencies, RBE-values of 2 to 3 and for the combined exposure RBE values of 1.5 to 2 were calculated for a range of effect of 0.5 to 1.5 micronuclei/binucleated lymphocyte. No indication was found for an interaction between the damage induced by X-rays and that produced by neutrons under our experimental conditions. (orig./MG) [Deutsch] Fragestellung: Die Mikronukeusinduktion in Lymphozyten wurde nach In-vitro-Bestrahlung mit 6-MeV-Neutronen (0,5 bis 4 Gy), 240-kV-Roentgenstrahlung (0,5 bis 5 Gy) bzw. einer Kombination dieser Strahlenqualitaeten (1 bis 3 Gy Gesamtdosis) untersucht. Anhand der Dosis-Wirkungs-Beziehungen fuer die einzelne und kombinierte Anwendung beider Strahlenarten wurde die relative biologische Wirksamkeit (RBW) fuer Neutronen bzw. fuer die Kombination von Neutronen und Roentgenstrahlen ermittelt. Mit Hilfe einer Isobolenkalkulation (`envelope of additivity`) wurde die Moeglichkeit einer Interaktion zwischen den

  9. [原著]Prethymic Nylon Wool-Passed Bone Marrow Cells Can Make Distinction between Self and Non-Self X-Chromosome-Linked Gene Products (Xir Antigens) on the Stimulator Cells, Resulting in Regulation of the Generation of Cytotoxic T Lymphocytes in Mixed Lymphocyte Cultures


    Higa, Moritake; Tanabe, MasaoJ; Department of Bacteriology, Faculty of, University of the Ryukyus, Okinawa, Japan; Research Institute of Comprehensive Medicine, School of Medicine, University of the Ryukyus, Okinawa, Japan


    We have previously reported that nylon wool-passed bone marrow cells treated with anti-Thy.1 antibody and complement (Thy.1 NW-BM cells) had helper-like activity which could augment the generation of cytotoxic T lymphocytes (CTL). In this study, we determined the antigens to which these NW-BM cells responded and recognized. When a few responder lymph node (LN) cells and an excess of NW-BM responder cells from BIOBR (H-2^k B10 background) mice were cultured with stimulator spleen cells from ei...

  10. Doxorubicin has a synergistic cytotoxicity with cucurbitacin B in anaplastic thyroid carcinoma cells. (United States)

    Kim, Si Hyoung; Kang, Jun Goo; Kim, Chul Sik; Ihm, Sung-Hee; Choi, Moon Gi; Yoo, Hyung Joon; Lee, Seong Jin


    In this study, the combined effect of doxorubicin with cucurbitacin B on survival of anaplastic thyroid carcinoma cells was evaluated. For experiments, 8505C and CAL62 human anaplastic thyroid carcinoma cells were used. Cell viability, the percentage of viable cells, and cytotoxic activity were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, multiplexed cytotoxicity assay, and cytotoxicity assay, respectively. Reactive oxygen species production was measured. In experiments, doxorubicin and cucurbitacin B reduced cell viability in a dose- and time-dependent manner. Cotreatment of doxorubicin and cucurbitacin B, compared with treatment of doxorubicin alone, decreased the percentage of viable cells and increased cytotoxic activity. All of the combination index values were lower than 1.0, suggesting the synergism between doxorubicin and cucurbitacin B in induction of cytotoxicity. In cells treated with both doxorubicin and cucurbitacin B, compared with doxorubicin alone, the protein levels of cleaved poly(adenosine diphosphate-ribose) polymerase and cyclooxygenase 2 and reactive oxygen species production were enhanced. In contrast, the protein levels of B-cell chronic lymphocytic leukemia/lymphoma 2 and survivin and B-cell chronic lymphocytic leukemia/lymphoma 2/B-cell chronic lymphocytic leukemia/lymphoma 2-associated x protein ratio were diminished. The protein levels of Janus kinase 2 and signal transducer and activator of transcription 3 were reduced, while phospho-extracellular signal-regulated kinase 1/2 protein levels were elevated without change in total extracellular signal-regulated kinase 1/2 protein levels. These results suggest that doxorubicin synergizes with cucurbitacin B in induction of cytotoxicity in anaplastic thyroid carcinoma cells. Moreover, synergistic cytotoxicity of doxorubicin with cucurbitacin B is mediated by B-cell chronic lymphocytic leukemia/lymphoma 2 family proteins, survivin, and reactive oxygen

  11. Quantitation of minimal disease levels in chronic lymphocytic leukemia using a sensitive flow cytometric assay improves the prediction of outcome and can be used to optimize therapy. (United States)

    Rawstron, A C; Kennedy, B; Evans, P A; Davies, F E; Richards, S J; Haynes, A P; Russell, N H; Hale, G; Morgan, G J; Jack, A S; Hillmen, P


    Previous studies have suggested that the level of residual disease at the end of therapy predicts outcome in chronic lymphocytic leukemia (CLL). However, available methods for detecting CLL cells are either insensitive or not routinely applicable. A flow cytometric assay was developed that can differentiate CLL cells from normal B cells on the basis of their CD19/CD5/CD20/CD79b expression. The assay is rapid and can detect one CLL cell in 10(4) to 10(5) leukocytes in all patients. We have compared this assay to conventional assessment in 104 patients treated with CAMPATH-1H and/or autologous transplant. During CAMPATH-1H therapy, circulating CLL cells were rapidly depleted in responding patients, but remained detectable in nonresponders. Patients with more than 0.01 x 10(9)/L circulating CLL cells always had significant (> 5%) marrow disease, and blood monitoring could be used to time marrow assessments. In 25 out of 104 patients achieving complete remission by National Cancer Institute (NCI) criteria, the detection of residual bone marrow disease at more than 0.05% of leukocytes in 6 out of 25 patients predicted significantly poorer event-free (P =.0001) and overall survival (P =.007). CLL cells are detectable at a median of 15.8 months (range, 5.5-41.8) posttreatment in 9 out of 18 evaluable patients with less than 0.05% CLL cells at end of treatment. All patients with detectable disease have progressively increasing disease levels on follow-up. The use of sensitive techniques, such as the flow assay described here, allow accurate quantitation of disease levels and provide an accurate method for guiding therapy and predicting outcome. These results suggest that the eradication of detectable disease may lead to improved survival and should be tested in future studies.

  12. Sitotoksisitas bahan restorasi cyanoacrylate pada variasi perbandingan powder dan liquid menggunakan MTT assay (Cytotoxicity of the cyanoacrylate restoration material with variation of powder and liquid ratio by using MTT assay

    Directory of Open Access Journals (Sweden)

    Asti Meizarini


    Full Text Available The requirements for dental material include not toxic, not irritant, no carcinogenic potential, nor cause an allergic response with the use in oral cavity. The cyanoacrylate restoration material has certain substance that can be toxic. Because of the ratio amount of powder and liquid is not known, it can lead the restoration more toxic. The purpose of this study was to know the cytotoxicity of the cyanoacrylate restoration material with different variation of powder and liquid ratio using MTT assay. Six cylinder samples of 5 mm in diameter and 2 mm in thickness were used for each group of 1:1.00; 1:0.75; 1:0.50 powder and liquid ratio of cyanoacrylate restoration materials. Each of samples was immersed in eppendorf micro tubes consisting of media culture. After 24 hour, the immersion of media culture was used to investigate the cytotoxic effect to BHK-21 cell lines by MTT assay method. The density of optic formazan indicated the amount of living cells. All data were statistically analyzed by one-way ANOVA and HSD. The results showed that the percentage of living cells amount of powder and liquid ratio 1:1.00; 1:0.75; 1:0.50 were 98.59%; 95.76%; 94.92% respectively. There was a significant difference between 1:1.00 and 1:0.50 group ratio. The conclusion was that the cytotoxicity between 1:1.00 and 1:0.50 powder and liquid ratio of cyanoacrylate restoration materials in this study decreased.

  13. 21. New developments in the lymphocyte micronucleus assay-the effect of diet, genotype and the importance of nucleoplasmic bridges

    Institute of Scientific and Technical Information of China (English)


    @@The cytokinesis-block micronucleus(CBMN)assay is an established method for studying chromosome breakage and loss in human cells both in vitro and in vivo. However, its use in the study of genomic stability could be improved by a better understanding of the impact of (a) micronutrients (b) genetic background and (c) of other associated important nuclear events indicative of chromosome rearrangement (ie nucleoplasmic

  14. Cytostatic and genotoxic effect of temephos in human lymphocytes and HepG2 cells. (United States)

    Benitez-Trinidad, A B; Herrera-Moreno, J F; Vázquez-Estrada, G; Verdín-Betancourt, F A; Sordo, M; Ostrosky-Wegman, P; Bernal-Hernández, Y Y; Medina-Díaz, I M; Barrón-Vivanco, B S; Robledo-Marenco, M L; Salazar, A M; Rojas-García, A E


    Temephos is an organophosphorus pesticide that is used in control campaigns against Aedes aegypti mosquitoes, which transmit dengue. In spite of the widespread use of temephos, few studies have examined its genotoxic potential. The aim of this study was to evaluate the cytotoxic, cytostatic and genotoxic effects of temephos in human lymphocytes and hepatoma cells (HepG2). The cytotoxicity was evaluated with simultaneous staining (FDA/EtBr). The cytostatic and genotoxic effects were evaluated using comet assays and the micronucleus technique. We found that temephos was not cytotoxic in either lymphocytes or HepG2 cells. Regarding the cytostatic effect in human lymphocytes, temephos (10 μM) caused a significant decrease in the percentage of binucleated cells and in the nuclear division index as well as an increase in the apoptotic cell frequency, which was not the case for HepG2 cells. The comet assay showed that temephos increased the DNA damage levels in human lymphocytes, but it did not increase the MN frequency. In contrast, in HepG2 cells, temephos increased the tail length, tail moment and MN frequency in HepG2 cells compared to control cells. In conclusion, temephos causes stable DNA damage in HepG2 cells but not in human lymphocytes. These findings suggest the importance of temephos biotransformation in its genotoxic effect.

  15. Evaluation on the cytotoxicity of Gallium alloy by MTT-assay%MTT法评价镓合金的细胞毒性

    Institute of Scientific and Technical Information of China (English)

    徐钢梅; 张彩霞; 宁丽; 孙皎; 孟爱英


    目的研究新型不含汞的牙体充填材料镓合金的细胞毒性。方法采用一种能快速评定细胞增殖率和细胞毒性的比色分析方法——MTT比色法,检测镓合金和高铜银汞合金对小鼠成纤维细胞L929细胞相对增殖率的影响,评价其细胞毒性。结果参照上海市医用生物材料生物性能测试标准,镓合金表现出较高的细胞相对增殖率,2 d时为93.0%±4.9%,4 d时为102.0%±3.5%,7 d时为107.2%±4.2%, 其细胞毒性为0级,即无明显细胞毒性;高铜银汞合金表现为中度细胞毒性。结论镓合金无明显的细胞毒性。%Objective To test the cytotoxicity of Gallium alloy, a new mercury-free dental restorative material. Methods L-929 mouse fibroblasts were used to detect the cell relative proliferation rate of Gallium alloy and high-copper amalgam by MTT-assay. Results The results indecated that the relative growth rate induced by Gallium alloy was high (93.0%±4.9% 2ds, 102.0%±3.5% 4ds, 107.2%±4.2% 7ds), and the cytotoxicity of Gallium alloy was 0 grade according to the Test Standard of Shanghai Medical Biomaterial, meaning Gallium alloy had no significant cytotoxicity and the relative growth rate of Gallium alloy was higher than that of high-copper amalgam.The high-copper amalgam showed medium cytotoxicity. Conclusion Gallium alloy has no significant cytotoxicity.


    Investigation ofDNA Repair by Sister Chromatid Exchange (SCE) Analysis and the Alkaline Single Cell Gel Assay (SCG) in Mammalian Go-Lymphocytes after In Vitro Exposure to Ethylene Oxide (EO). EO is a large volume chemical used primarily as an intermediate in manufacturing...

  17. Salvia somalensis essential oil as a potential cosmetic ingredient: solvent-free microwave extraction, hydrodistillation, GC-MS analysis, odour evaluation and in vitro cytotoxicity assays. (United States)

    Villa, C; Trucchi, B; Bertoli, A; Pistelli, L; Parodi, A; Bassi, A M; Ruffoni, B


    Salvia somalensis Vatke, a wild sage native of Somalia, has been studied with the aim of assessing the potential cosmetic application of its essential oil, recovered from fresh aerial parts by solvent-free microwave extraction - SFME. To evaluate the efficiency and reliability of this eco-friendly procedure, the recovery of the essential oil was also processed by conventional hydrodistillation (HD) and the results compared. The essential oils obtained by both SFME and HD were analysed by gas chromatography-mass spectrometry using apolar and polar capillary columns. The essential oil recovered by SFME was submitted to an odour evaluation that revealed peculiar olfactive characteristics interesting in alcoholic male perfumery and body detergents.In vitro cytotoxicity assays were carried out using NCTC 2544 human keratinocytes as target cells. The oil displayed slight cytotoxic effects, which were three orders of magnitude lower than those found for sodium dodecyl sulphate positive control. The promising results in terms of chemical composition, scent and safety seem to indicate this essential oil as an interesting potential functional ingredient useful in a cosmetic context.

  18. Cytotoxicity and Inhibition of Lymphocyte Proliferation of Fasciculatin, a Linear Furanosesterterpene Isolated from Ircinia variabilis Collected from the Atlantic Coast of Morocco

    Directory of Open Access Journals (Sweden)

    Werner Herz


    Full Text Available Abstract: Fasciculatin, a furanosesterterpene isolated from the marine sponge Ircinia variabilis from the Atlantic Coast of Morocco, has been evaluated for its influence on a mitogen-induced proliferation of human lymphocytes and growth of human tumor cell lines.

  19. Site-directed mutagenesis of an HLA-A3 gene identifies amino acid 152 as crucial for major-histocompatibility-complex-restricted and alloreactive cytotoxic-T-lymphocyte recognition.


    Cowan, E P; Jelachich, M L; Coligan, J E; Biddison, W E


    Major histocompatibility complex-restricted and alloreactive cytotoxic T lymphocytes (CTL) can discriminate between the HLA-A3.1 and HLA-A3.2 antigens. HLA-A3.1 and the rare variant HLA-A3.2 have been shown to differ by two amino acids in the alpha 2 domain at positions 152 (A3.1, glutamic acid; A3.2, valine) and 156 (A3.1, leucine; A3.2, glutamine). To determine the structural basis for the ability of CTL to differentiate A3.1 from A3.2, two site-directed mutants of the HLA-A3.2 gene were pr...

  20. Successful kidney transplantation across a positive complement-dependent cytotoxicity crossmatch by using C1q assay-directed, bortezomib-assisted desensitization (United States)

    Lee, Juhan; Park, Borae G.; Jeong, Hyang Sook; Park, Youn Hee; Kim, Sinyoung; Kim, Beom Seok; Kim, Hye Jin; Huh, Kyu Ha; Jeong, Hyeon Joo; Kim, Yu Seun


    Abstract Rationale: Human leukocyte antigen (HLA) is the major immunologic barrier in kidney transplantation (KT). Various desensitization protocols to overcome the HLA barrier have increased the opportunity for transplantation in sensitized patients. In addition, technological advances in solid-phase assays have permitted more comprehensive assessment of donor-specific antibodies. Although various desensitization therapies and immunologic techniques have been developed, the final transplantation decision is still based on the classic complement-dependent cytotoxicity (CDC) crossmatch (XM) technique. Some patients who fail to achieve negative XM have lost their transplant opportunities, even after receiving sufficient desensitization therapies. Patient concerns: A 57-year-old male with end-stage renal disease secondary to chronic glomerulonephritis was scheduled to have a second transplant from his son, but CDC XM was positive. Diagnoses: Initial CDC XM (Initial T-AHG 1:32) and flow-cytometry XM were positive. Anti-HLA-B59 donor specific antibody was detected by Luminex single antigen assay. Interventions: Herein, we report a successful case of KT across a positive CDC XM (T-AHG 1:8 at the time of transplantation) by using C1q assay-directed, bortezomib-assisted desensitization. After confirming a negative conversion in the C1q donor-specific antibody, we decided to perform KT accepting a positive AHG-CDC XM of 1:8 at the time of transplantation. Outcomes: The posttransplant course was uneventful and a protocol biopsy at 3 months showed no evidence of rejection. The patient had excellent graft function at 12 months posttransplant. Lessons: The results of XM test and solid-phase assay should be interpreted in the context of the individual patient. PMID:28953652

  1. Measurement of the cytotoxic effects of different strains of Mycoplasma equigenitalium on the equine uterine tube using a calmodulin assay. (United States)

    Bermúdez, V M; Miller, R B; Rosendal, S; Fernando, M A; Johnson, W H; O'Brien, P J


    The cytopathic effects induced by five strains of Mycoplasma equigenitalium for cells of equine uterine tube explants were tested by measuring changes in cellular and extracellular concentrations of calmodulin (CaM). Calmodulin concentrations in samples of total homogenate (TH) and total homogenate supernates (THS) of the infected equine uterine tube explants were significantly lower than respective measurements on noninfected controls. In tissue culture medium fractions (TCM) of some infected explants, CaM concentrations were significantly higher than noninfected controls (p > 0.95). The results suggest that M. equigenitalium colonization on ciliated cells of the equine uterine tube can affect the permeability of the cell membrane leading to leakage or release of CaM during cell breakdown. Measurement of CaM concentrations in samples of TH revealed significant differences in the cytotoxic effects induced by different strains of M. equigenitalium on the equine uterine tube (EUT). The data suggests that some strains of M. equigenitalium may have a role in reproductive failure in the mare. In addition comparisons of the means of the concentrations of CaM in samples of TH or THS in EUT explants from four mares in the follicular and four in the luteal phase of the estrous cycle were found to be not significantly different. PMID:1477802

  2. Mycobacterium avium and purified protein derivative-specific cytotoxicity mediated by CD4+ lymphocytes from healthy HIV-seropositive and-seronegative individuals

    DEFF Research Database (Denmark)

    Ravn, P; Pedersen, B K


    to respond to mycobacterial antigens. The immunological dysfunction leading to reduced mycobacterial-specific cytotoxic activity in healthy HIV-seropositive subjects is caused either by a reduction in the number of antigen-responsive CD4+ T cells (memory) or by an impairment of their ability to respond...

  3. Program death-1 signaling and regulatory T cells collaborate to resist the function of adoptively transferred cytotoxic T lymphocytes in advanced acute myeloid leukemia

    National Research Council Canada - National Science Library

    Zhou, Qing; Munger, Meghan E; Highfill, Steven L; Tolar, Jakub; Weigel, Brenda J; Riddle, Megan; Sharpe, Arlene H; Vallera, Daniel A; Azuma, Miyuki; Levine, Bruce L; June, Carl H; Murphy, William J; Munn, David H; Blazar, Bruce R


    ...) and elevation of program death-1 (PD-1) expression on CD8(+) cytotoxic T cells (CTLs) at the tumor site. PD-1 knockout mice were more resistant to AML despite the presence of similar percentage of Tregs compared with wild type...

  4. G-banding chromosomal aberration assay of lymphocyte after radiation%辐射后淋巴细胞的G显带染色体畸变分析

    Institute of Scientific and Technical Information of China (English)

    赵明刚; 施常备; 赵华; 袁勇; 姚俊涛; 陆建荣; 袁彬; 陈葳; 王翔


    目的:通过染色体G显带技术研究辐射后染色体的结构畸变情况.方法:4MV的X线辐射离体入血,淋巴细胞培养后,应用染色体G显带技术,分析辐射后染色体的结构畸变情况,包括双着丝粒、缺失、易位、环状染色体、染色体片段,等.结果:辐射后观察分散良好、形态清晰的细胞核型100个,染色体畸变总数为428,其中双着丝粒、缺失、易位、环状染色体、染色体片段的发生数分别为 86、41、111、9、181.分析各号染色体辐射后畸变情况,未见明显差异.结论:染色体G带分析可以提供较丰富的染色体结构畸变信息.%Objective : To validate the value of G - banding chromosomal aberration of lymphocyte after radiation. Methods : The blood was irradiated by 4 MV X - ray and was cultured 3 days. The G - banding chromosomal aherration was assayed including dicentrics, deletions, translocations, rings, and fragments chromosomal aberration. Results:There were 100 good karyotypes observed. The total of chromosomal aberration was 428. The dicentric, deletion, translocation, ring, and fragment chromosomal aberration were 86, 41 , 111 , 9, and 181 respectively. There was no significant difference in chromosomal aherration after radiation in every NO. chromosome. Conclusion : The G - banding chromosomal aberration assay should be paid more attention in radiation biology.

  5. CTL ELISPOT assay. (United States)

    Ranieri, Elena; Popescu, Iulia; Gigante, Margherita


    Enzyme-linked immune absorbent spot (Elispot) is a quantitative method for measuring relevant parameters of T cell activation. The sensitivity of Elispot allows the detection of low-frequency antigen-specific T cells that secrete cytokines and effector molecules, such as granzyme B and perforin. Cytotoxic T cell (CTL) studies have taken advantage with this high-throughput technology by providing insights into quantity and immune kinetics. Accuracy, sensitivity, reproducibility, and robustness of Elispot resulted in a wide range of applications in research as well as in diagnostic field. Actually, CTL monitoring by Elispot is a gold standard for the evaluation of antigen-specific T cell immunity in clinical trials and vaccine candidates where the ability to detect rare antigen-specific T cells is of relevance for immune diagnostic. The most utilized Elispot assay is the interferon-gamma (IFN-γ) test, a marker for CD8(+) CTL activation, but Elispot can also be used to distinguish different subsets of activated T cells by using other cytokines such as T-helper (Th) 1-type cells (characterized by the production of IFN-γ, IL-2, IL-6, IL-12, IL-21, and TNF-α), Th2 (producing cytokines like IL-4, IL-5, IL-10, and IL-13), and Th17 (IL-17) cells. The reliability of Elispot-generated data, by the evaluation of T cell frequency recognizing individual antigen/peptide, is the core of this method currently applied widely to investigate specific immune responses in cancer, infections, allergies, and autoimmune diseases. The Elispot assay is competing with other methods measuring single-cell cytokine production, e.g., intracellular cytokine by FACS or Miltenyi cytokine secretion assay. Other types of lymphocyte frequency and function assays include limiting dilution assay (LDA), cytotoxic T cell assay (CTL), and tetramer staining. Compared with respect to sensitivity the Elispot assay is outranking other methods to define frequency of antigen-specific lymphocytes. The method

  6. T-lymphocyte and B-lymphocyte dichotomy in anuran amphibians: III. Assessment and identification of inducible killer T-lymphocytes (IKTL) and spontaneous killer T-lymphocytes (SKTL). (United States)

    Klempau, A E; Cooper, E L


    We have established the existence of alloreactive inducible killer (IK) T-lymphocytes in Rana pipiens by injecting immunogenic concentrations of allogeneic frog erythrocytes (RBC). Assessment of specific IK activity was determined microscopically, observing effector-target conjugate formation, and spectrophotometrically as released hemoglobin (Hb) from lysed targets (RBC). The presence of spontaneous killer (SK) T-lymphocyte activity was also determined using unimmunized frogs and similar assay conditions. Assays using rabbit anti-frog Thy-1.1 antiserum inhibition, but not E-rosetted T-lymphocyte depletion, confirmed the T-lymphocyte category of both effector cell populations in Rana pipiens. For IK activity, we determined the 1) best priming doses, 2) best effector cell source (peripheral blood), 3) best priming route (intraperitoneal), 4) kinetics of immunity development, and 5) kinetics of lysis. Kinetics of lysis and organ distribution for spontaneous killer cells were also determined. Our results may assist 1) in establishing the evolutionary origin of cytotoxic T-lymphocytes (CTL) and natural killer (NK) cells, and 2) in predicting where the capacity of immuno-surveillance against modified-self appeared in phylogeny. The implications are important for understanding origins of mechanisms of resistance against neoplastic conditions.

  7. Highly Oxygenated Sesquiterpene Lactones from Cousinia aitchisonii and their Cytotoxic Properties: Rhaserolide Induces Apoptosis in Human T Lymphocyte (Jurkat) Cells via the Activation of c-Jun n-terminal Kinase Phosphorylation. (United States)

    Iranshahy, Milad; Tayarani-Najaran, Zahra; Kasaian, Jamal; Ghandadi, Morteza; Emami, Seyed Ahmad; Asili, Javad; Chandran, Jima N; Schneider, Bernd; Iranshahi, Mehrdad


    Infrared-guided chromatographic fractionation of sesquiterpene lactones from the extracts of Cousinia aitchisonii and Cousinia concolor led to the isolation of five pure compounds. A new sesquiterpene lactone, namely, aitchisonolide, and two known sesquiterpene lactones (desoxyjanerin and rhaserolide) were isolated from C. aitchisonii and two known lignans (arctiin and arctigenin) from C. concolor. The structures of these compounds were elucidated by one-dimensional and two-dimensional nuclear magnetic resonance techniques, as well as high-resolution mass spectrometry. The purified and characterized compounds were subjected to cytotoxicity assay. The sesquiterpene lactones desoxyjanerin and rhaserolide showed significant cytotoxic activities against five different cancer cell lines and the normal human embryonic kidney cell line. Rhaserolide was chosen to evaluate the possible mechanism of action. Western blot analysis revealed that rhaserolide could induce apoptosis in Jurkat cells via the activation of c-Jun n-terminal kinase phosphorylation.

  8. Development of an optimized cytotoxicity assay system for CYP3A4-mediated metabolic activation via modified piggyBac transposition. (United States)

    Huang, Lizhen; Zou, Shuxiang; Deng, Jifeng; Dai, Tianming; Jiang, Jingwei; Jia, Ying; Dai, Renke; Xie, Shuilin


    Drug-induced hepatotoxicity is often caused by cytochrome P450 (CYP)-dependent metabolism of drugs into reactive metabolites. Assessment of hepatotoxicity induced by bioactive compounds is hampered by low CYP expression within in vitro cell lines. To overcome this limitation, piggyBac transposition and monoclonal expansion were used to generate a HepG2 cell line with stable and homogenously high expression of CYP3A4, a prominent CYP isoform. Our studies demonstrate the generated line's constant CYP3A4 expression and activity for over 40 cell passages; to date, it has been in subculture for more than a year without addition of Puromycin. This cell line was utilized to evaluate cytotoxicity of two bioactive (troglitazone and acetaminophen) and two non-bioactive (citrate and galactosamine) compounds by MTT assay. Cell viability significantly decreased upon treatment with bioactive drugs. Moreover, cell lines used in the present study were more sensitive to toxic effects of troglitazone than previously reported. Therefore, this HepG2 cell-based assay system may provide a suitable hepatic model for predicting CYP3A4-mediated hepatotoxicity during preclinical drug development.

  9. Differential toxicity of Disperse Red 1 and Disperse Red 13 in the Ames test, HepG2 cytotoxicity assay, and Daphnia acute toxicity test. (United States)

    Ferraz, E R A; Umbuzeiro, G A; de-Almeida, G; Caloto-Oliveira, A; Chequer, F M D; Zanoni, M V B; Dorta, D J; Oliveira, D P


    Azo dyes are of environmental concern due to their degradation products, widespread use, and low-removal rate during conventional treatment. Their toxic properties are related to the nature and position of the substituents with respect to the aromatic rings and amino nitrogen atom. The dyes Disperse Red 1 and Disperse Red 13 were tested for Salmonella mutagenicity, cell viability by annexin V, and propidium iodide in HepG2 and by aquatic toxicity assays using daphnids. Both dyes tested positive in the Salmonella assay, and the suggestion was made that these compounds induce mainly frame-shift mutations and that the enzymes nitroreductase and O-acetyltransferase play an important role in the observed effect. In addition, it was shown that the presence of the chlorine substituent in Disperse Red 13 decreased the mutagenicity about 14 times when compared with Disperse Red 1, which shows the same structure as Disperse Red 13, but without the chlorine substituent. The presence of this substituent did not cause cytotoxicity in HepG2 cells, but toxicity to the water flea Daphnia similis increased in the presence of the chlorine substituent. These data suggest that the insertion of a chlorine substituent could be an alternative in the design of dyes with low-mutagenic potency, although the ecotoxicity should be carefully evaluated.

  10. Correlation between Clostridium difficile bacterial load, commercial real-time PCR cycle thresholds, and results of diagnostic tests based on enzyme immunoassay and cell culture cytotoxicity assay. (United States)

    Dionne, Léa-Laurence; Raymond, Frédéric; Corbeil, Jacques; Longtin, Jean; Gervais, Philippe; Longtin, Yves


    The impact of Clostridium difficile fecal loads on diagnostic test results is poorly understood, but it may have clinical importance. In this study, we investigated the relationship between C. difficile fecal load and the results of four assays: a glutamate dehydrogenase (GDH) enzyme immunoassay (EIA), a toxin A/B antigen EIA (ToxAB), a cell culture cytotoxicity assay (CCA), and PCR targeting the tcdB gene. We also compared the PCR cycle threshold (CT) with the results of quantitative culture using Spearman's rank correlation coefficient. Finally, we sequenced the genomes of 24 strains with different detection profiles. A total of 203 clinical samples harboring toxigenic C. difficile were analyzed and sorted into one of four groups: 17 PCR(+) (group 1), 37 PCR(+) GDH(+) (group 2), 24 PCR(+) GDH(+) CCA(+) (group 3), and 125 PCR(+) GDH(+) ToxAB(+) (group 4). The overall median fecal load in log10 CFU/g was 6.67 (interquartile range [IQR], 5.57 to 7.54). The median fecal bacterial load of groups 1, 2, 3, and 4 were 4.15 (IQR, 3.00 to 4.98), 5.74 (IQR, 4.75 to 6.16), 6.20 (IQR, 5.23 to 6.80), and 7.08 (IQR, 6.35 to 7.83), respectively. Group 1 samples had lower fecal loads than those from each of the other groups (P tests.

  11. Study on the Cytotoxic T Lymphocytes Clone Specific for the Nucleocapsid Protein of Hantaan Virus from Peripheral Blood in Patients with Hemorrhagic Fever with Renal Syndrome

    Institute of Scientific and Technical Information of China (English)

    潘蕾; 白雪帆; 黄长形; 李光玉


    In order to elucidate the molecular and immunological mechanisms as well as the pathogenesis of hemorrhagic fever with renal syndrome (HFRS), the CD8+ cytotoxic T lymphecytes (CTL) clone was established directly from peripheral blood mononuclear cells (PBMC) of patients with HFRS. The activities of CTL were detected as usual with EBV-transformed lymphoblastoid cell line (BLCL) as target cells. The results showed that the CTL clone could recognized and killed the targetcells with specificity of nucleocapsid protein of Hantaan virus (HTNVNP) with the cytotoxicity percentages of 50.2%,25.4% and 39.0% respectively. These results demonstrated that the antigenic epitopes of HTNVNP mainly located on the C-temainal of the viral nucleocapsid protein.

  12. High-dose survival in the lymphocytic choriomeningitis virus infection is accompanied by suppressed DTH but unaffected T-cell cytotoxicity

    DEFF Research Database (Denmark)

    Marker, O; Thomsen, Allan Randrup; Volkert, M


    cells and infected sensitive targets in the central nervous system. On the other hand, high doses of virus caused a clear suppression of the LCMV-specific delayed-type hypersensitivity (DTH). In addition, when splenocytes from high-dose animals were transferred either intravenously or locally...... in mice infected with these doses of virus. In the high-dose mice we found generally higher organ virus titres and serum interferon titres than in the low-dose mice. Since we could demonstrate that virus-specific T-cell cytotoxicity in spleen, peripheral blood, and meningeal exudate was similar after...... intracerebral infection with large and small virus doses, and since the LCMV infection in the brain qualitatively and quantitatively was independent of the size of virus inoculum, the explanation for the survival of the high-dose animals is obviously not lack of possibilities for interaction between cytotoxic T...

  13. New polycomb group protein enhancer of zeste homolog (EZH) 2-derived peptide with the potential to induce cancer-reactive cytotoxic T lymphocytes in prostate cancer patients with HLA-A3 supertype alleles. (United States)

    Minami, Takafumi; Minami, Tomoko; Shimizu, Nobutaka; Yamamoto, Yutaka; De Velasco, Marco A; Nozawa, Masahiro; Yoshimura, Kazuhiro; Harashima, Nanae; Harada, Mamoru; Uemura, Hirotsugu


    Analyses on reactivity of anti-cancer cytotoxic T lymphocytes (CTLs) and clinical application of peptide-based anti-cancer vaccine have been mainly focused on patients with HLA-A2 or -A24 alleles. In this study, we identified an enhancer of zeste homolog (EZH) 2-derived peptide applicable for anti-cancer vaccine for prostate cancer patients with HLA-A3 supertype alleles. Five EZH2-derived peptides that were prepared based on the binding motif to the HLA-A3 supertype alleles (HLA-A11, -A31, and -A33) were functionally screened for their potential to induce peptide-specific CTLs from peripheral blood mononuclear cells (PBMCs) of HLA-A3 supertype allele(+) prostate cancer patients. As a result, EZH2733-741 peptide was found to efficiently induce peptide-specific CTLs. The EZH2733-741 peptide-stimulated and purified CD8(+) T cells from PBMCs of HLA-A3 supertype allele(+) prostate cancer patients showed higher cytotoxicity against HLA-A3 supertype allele-expressing LNCaP prostate cancer cells than against parental LNCaP cells. This cytotoxicity against HLA-A3 supertype allele-expressing LNCaP cells was partially but significantly inhibited by the addition of EZH2733-741 peptide-pulsed competitive cells. These results indicate that the EZH2733-741 peptide could be a promising candidate for peptide-based immunotherapy for HLA-A3 supertype allele(+) prostate cancer patients.

  14. Induction of the Epstein-Barr Virus Latent Membrane Protein 2 Antigen-specific Cytotoxic T Lymphocytes Using Human Leukocyte Antigen Tetramer-based Artificial Antigen-presenting Cells

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ling LU; Zhi-Hui LIANG; Cai-E ZHANG; Sheng-Jun LU; Xiu-Fang WENG; Xiong-Wen WU


    Cytotoxic T lymphocytes (CTLs) specific for the Epstein-Barr virus (EBV) latent membrane protein 2 (LMP2) antigen are important reagents for the treatment of some EBV-associated malignancies,such as EBV-positive Hodgkin's disease and nasopharyngeal carcinoma. However, the therapeutic amount of CTLs is often hampered by the limited supply of antigen-presenting cells. To address this issue, an artificial antigen-presenting cell (aAPC) was made by coating a human leukocyte antigen (HLA)-pLMP2 tetrameric complex, anti-CD28 antibody and CD54 molecule to a cell-sized latex bead, which provided the dual signals required for T cell activation. By co-culture of the HLA-A2-LMP2 bearing aAPC and peripheral blood mononuclear cells from HLA-A2 positive healthy donors, LMP2 antigen-specific CTLs were induced and expanded in vitro. The specificity of the aAPC-induced CTLs was demonstrated by both HLA-A2-LMP2tetramer staining and cytotoxicity against HLA-A2-LMP2 bearing T2 cell, the cytotoxicity was inhibited by the anti-HLA class I antibody (W6/32). These results showed that LMP2 antigen-specific CTLs could be induced and expanded in vitro by the HLA-A2-LMP2-bearing aAPC. Thus, aAPCs coated with an HLApLMP2 complex, anti-CD28 and CD54 might be promising tools for the enrichment of LMP2-specific CTLs for adoptive immunotherapy.

  15. Human T cell priming assay: depletion of peripheral blood lymphocytes in CD25(+) cells improves the in vitro detection of weak allergen-specific T cells. (United States)

    Vocanson, Marc; Achachi, Amine; Mutez, Virginie; Cluzel-Tailhardat, Magalie; Varlet, Béatrice Le; Rozières, Aurore; Fournier, Philippe; Nicolas, Jean-François


    To develop an in vitro assay that recapitulates the key event of allergic contact dermatitis (ACD), that is the priming of effector T cells by hapten-presenting dendritic cells, and then allows for the sensitive detection of chemical allergens represents a major challenge. Classical human T cell priming assays (hTCPA) that have been developed in the past, using hapten-loaded monocyte-derived dendritic cells (MDDCs) as antigen-presenting cells and peripheral blood lymphocytes (PBLs) as responding cells, were not efficient to prime T cells to common allergens with moderate/weak sensitizing properties. Recent progress in the understanding of the effector and regulatory mechanisms of ACD have shown that T cell priming requires efficient uptake of allergens by immunogenic DCs and that it is controlled by several subsets of regulatory cells including CD25(+) Tregs. We therefore analyzed various parameters involved in allergen-specific T cell activation in vitro and showed that priming of allergen-specific T cells is hampered by several subsets of immune cells comprising CD1a(neg) DCs, CD25(+) T cells, and CD56(+) regulatory cells.CD4(+)CD25(+)FoxP3(+) Tregs prevented the in vitro T cell priming to moderate/weak allergens, and depletion of human PBLs in CD25(+) cells significantly increased specific T cell proliferation and IFN-γ secretion. CD56(+) cells exerted an additional control of T cell priming since co-depletion of both CD56(+) and CD25(+) cells improved the magnitude of chemical-specific T cell activation. Finally, CD1a(low) MDDCs were able to inhibit T cell activation obtained by allergen-pulsed CD1a(high) MDDC. Moreover, we showed that uptake by DC of allergen-encapsulated nanoparticles significantly increased their activation status and their ability to prompt specific T cell activation. Hence, by combining the different strategies, i.e., depletion of CD25(+) and CD56(+) cells, use of CD1a(high) MDDC, and nanoparticle encapsulation of allergens, it was

  16. Combining the rapid MTT formazan exocytosis assay and the MC65 protection assay led to the discovery of carbazole analogs as small molecule inhibitors of Abeta oligomer-induced cytotoxicity. (United States)

    Hong, Hyun-Seok; Maezawa, Izumi; Yao, Nianhuan; Xu, Bailing; Diaz-Avalos, Ruben; Rana, Sandeep; Hua, Duy H; Cheng, R Holland; Lam, Kit S; Jin, Lee-Way


    The discovery of small molecule inhibitors of cytotoxicity induced by amyloid-beta (Abeta) oligomers, either applied extracellularly or accumulated intraneuronally, is an important goal of drug development for Alzheimer's disease (AD), but has been limited by the lack of efficient screening methods. Here we describe our approach using two cell-based methods. The first method takes advantage of the unique ability of extracellularly applied Abeta oligomers to rapidly induce the exocytosis of formazan formed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). We employed a short protocol to quantify this toxicity, and quickly identified two novel inhibitors, code-named CP2 and A5, from two compound libraries. A second independent screen of the same libraries using our previously published MC65 protection assay, which identifies inhibitors of toxicity related to intracellular Abeta oligomers, also selected the same two leads, suggesting that both assays select for the same anti-Abeta oligomer properties displayed by these compounds. We further demonstrated that A5 attenuated the progressive aggregation of existing Abeta oligomers, reduced the level of intracellular Abeta oligomers, and prevented the Abeta oligomer-induced death of primary cortical neurons, effects similar to those demonstrated by CP2. Our results suggest that, when combined, the two methods would generate fewer false results and give a high likelihood of identifying leads that show promises in ameliorating Abeta oligomer-induced toxicities within both intraneuronal and extracellular sites. Both assays are simple, suitable for rapid screening of a large number of medicinal libraries, and amenable for automation.

  17. Hepatocyte damage induced by lymphocytes from patients with chronic liver diseases, as detected by LDH release. (United States)

    Fernandez-Cruz, E; Escartin, P; Bootello, A; Kreisler, M; Segovia de Arana, J M


    We have used a cytoplasmic enzyme system in the study of the in vitro cytotoxic activity of human peripheral blood leucocytes against isolated liver cells in patients with chronic liver diseases. Lymphocytes from primary biliary cirrhosis and chronic active liver disease patients were shown to have an in vitro capacity to induce a cytolitic effect on isolated hepatocytes, as demonstrated by the enhanced release of lactate dehydrogenase (LDH), a cytoplasmic marker enzyme. No significant LDH release was seen with control lymphocytes of normal persons or with lymphocytes from patients with alcoholic cirrhosis. Our results corroborate, in a different assay system, by a simple, reproducible and different method, that lymphocyte-mediated liver cell damage "in vitro" occurs in both primary biliary cirrhosis and chronic active liver disease. PMID:657588

  18. Antioxidant Activities and Cytotoxicity of Zingiber zerumbet (L. Smith Rhizome

    Directory of Open Access Journals (Sweden)

    Anish Nag


    Full Text Available Zingiber zerumbet (L. Smith, popularly known as shampoo ginger, is one of the most commonly used ingredients in Indo-Malaysian traditional medicines. The antioxidant and cytotoxic activities of the ethanolic extract of Z. zerumbet rhizome (ZZ was investigated. 2,2-di(4-tert-octylphenyl-1- picryl-hydrazyl (DPPH and hydroxyl radical scavenging assays showed significant radical scavenging activities of ZZ. The extract was rich in polyphenol and flavonoids. Cytotoxicity was assessed in vitro by trypan blue exclusion test. Human peripheral blood lymphocyte cells were incubated in different concentrations of ZZ (0, 15, 30, 60, 120, 300 and 600 µg/ml for 3 h at 37 °C. The rhizome extract was found to be cytotoxic at concentrations higher for human consumption. In addition, HPLC analysis revealed ZZ as a rich source of kaempferol. Based on the results of the present investigation the rhizome may be used safely as a therapeutic antioxidant.

  19. Activity of vinorelbine on B-chronic lymphocytic leukemia cells in vitro. (United States)

    Bernabei, P A; Landini, I; Bartolozzi, B; Banchelli, I; Degli Innocenti o Nocentini, A; Santini, V; Ematologia, U O


    Vinorelbine (VNR) is a new semi-synthetic Vinca rosea alkaloid that has been employed both in combination and as a single agent, showing a significant antitumour activity. Since little is known about VNR in human leukemia, we studied the in vitro cytotoxic effect of VNR on peripheral blood lymphocytes from 18 patients affected by B-chronic lymphocytic leukemia (CLL), employing the INT assay. VNR inhibited fresh B-CLL cells from 15/18 patients in primary cultures, the ID50 doses ranging from 4 ng/ml to 83 micrograms/ml. These data strongly suggest that VNR could be effective in the treatment of B-CLL.

  20. Identification and ranking of poly (ADP-ribose) polymerase inhibitors as protectors against sulfur mustard induced decrease in cellular energy and viability in in vitro assays with human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Meier, H.L.; Kelly, S.A.


    Lymphocyte were utilized as a model for investigating HD effects on resting cells. Lymphocytes exposed to HD demonstrated a concentration dependent decrease in ATP, NAD, and viability. The decrease began in 15 minutes for ATP, 2 hours for NAD, and 6 hours for viability. All three of these HD initiated biochemical changes can be blocked by poly (ADP-ribose) polymerase inhibitors (PADPRPI). To completely inhibit HD initiated ATP, NAD, and viability decreases the PADPRPI had to be present at time 0, 1, and 4 hours respectfully. The amount of protection conferred by the PADPRPI in the viability assay decreased in a linear manner with the delay of the addition and the concentration of the inhibitor from 6-12 hours post HD exposure. There was a good correlation between IC50 to inhibit poly (ADP-ribose) polymerase and EC50 prevention of HD initiated cell death (r=O.94). Thus, three in vitro assays which can measure biochemical and pathologic changes induced by HD in G sub 0 lymphocytes have been developed. These assays have been employed to study the ability of candidate antidotes to prevent HD initiated changes. Benzamidine analogs, including the F.D.A. approved vitamin niacinamide, have been shown to be effective at inhibiting all of these changes.

  1. Cytotoxicity study of plant Aloe vera (Linn

    Directory of Open Access Journals (Sweden)

    Atul N Chandu


    Full Text Available Background: The objective of this study has been to evaluate the in-vitro antitumor activity of Aloe vera extract of in cultured B16F10 melanoma cell line by measuring cell viability using "Trypan blue exclusion assay" method. Aim: To find out such kind of anticancer drug which is a cheap, safe, less toxic, and more potent drug compared to chemotherapy drug. Materials and Methods: In-vitro antitumor activity cell culture1, drug treatment (standard and test extract and Trypan blue exclusion assay growth and viability test 1 were used. Treatment of Aloe vera extract against B16F10 melanoma cell line, in all concentration range, showed decrease in percent cell viability, as compared to that of negative when examined by "Trypan blue exclusion assay". Results: In overall variation of test samples, Aloe vera extract showed its best activity in the concentration of 300 μg/ml, which was approximately equal to the activity of standard drug doxorubicin. Evaluation of in-vitro antitumor activity revealed that Aloe vera extract exhibits good cytotoxic activity. The best cytotoxic activity by Aloe vera was shown at 200 μg/ml concentration. Conclusion: The study of cytoprotection against normal cells by micronucleus assay has shown that the herbal extracts have less toxic effects to the normal blood lymphocytes, as compared to that of standard anticancer drug.

  2. Synthesis and Characterization of Organotin(IV N-Benzyl-N-Isopropyldithiocarbamate Compounds: Cytotoxic Assay on Human Hepatocarcinoma Cells (HepG2

    Directory of Open Access Journals (Sweden)

    Normah Awang


    Full Text Available Problem statement: Several studies on organotin(IV dithiocarbamate compounds have been carried out but not on the synthesis and characterization together with cytotoxic assay of organotin(IV N-benzyl-N-isopropyldithiocarbamate compounds. Approach: Three new organotin(IV compounds of type N-benzyl-N-isopropyldithiocarbamate have been successfully synthesized by direct reaction between secondary amine with organotin(IV chloride using in situ method. All the compounds were characterized using elemental analysis, gravimetric analysis, infrared spectroscopy and Nuclear Magnetic Resonance (NMR spectroscopy. Results: Elemental and gravimetric analyses data of these compounds showed that agreed with the predicted formula, (CH32Sn[S2CN(C7H7(i-C3H7]2 (1, (C4H72Sn[S2CN(C7H7(i-C3H7]2 (2 and (C6H53Sn[S2CN(C7H7(i-C3H7] (3. The infrared spectra of these compounds showed the thioureide bond, v(C=N which occurred at 1438-1440 cm-1 and the v(C=S band appeared in the range of 967-973 cm-1. The presence of the v(C=N and v(C=S bands in the infrared spectra confirmed the presence of dithiocarbamate ligand in that compounds. The bond between sulphur and tin atom were supported with the presence of peak in the range of 365-445 cm-1 that known to be as stretching mode of v(Sn-S. The most important signal in the 13C NMR spectra was the chemical shift of NCS2 group. The 13C NMR spectra of these compound showed a chemical shift in 195.06-202.65 ppm range, which is attributed to the carbon atom of NCS2 group. The crystal structure of compound 2 (dibutyltin(IV N-benzyl-N-isopropyldithiocarbamate has been determined by X-ray single crystal analysis, which shows unsymmetrical nature of the ligand towards coordination to tin. It crystallizes in triclinic P1 space group with the crystal cell parameter: a = 17.7745 (2 (�, b = 19.5463 (3 (�, c = 26.2062 (4 (�, α = 102.5254 (7�, β = 95.1492 (7�, γ= 110.2569 (8�, Z = 10, V (�3 = 8202.1 (2

  3. Primary hemocyte culture of Penaeus monodon as an in vitro model for white spot syndrome virus titration, viral and immune related gene expression and cytotoxicity assays. (United States)

    Jose, Seena; Mohandas, A; Philip, Rosamma; Bright Singh, I S


    Immortal cell lines have not yet been reported from Penaeus monodon, which delimits the prospects of investigating the associated viral pathogens especially white spot syndrome virus (WSSV). In this context, a method of developing primary hemocyte culture from this crustacean has been standardized by employing modified double strength Leibovitz-15 (L-15) growth medium supplemented with 2% glucose, MEM vitamins (1×), tryptose phosphate broth (2.95 gl⁻¹), 20% FBS, N-phenylthiourea (0.2 mM), 0.06 μg ml⁻¹ chloramphenicol, 100 μg ml⁻¹ streptomycin and 100 IU ml⁻¹ penicillin and hemolymph drawn from shrimp grown under a bio-secured recirculating aquaculture system (RAS). In this medium the hemocytes remained viable up to 8 days. 5-Bromo-2'-deoxyuridine (BrdU) labeling assay revealed its incorporation in 22 ± 7% of cells at 24h. Susceptibility of the cells to WSSV was confirmed by immunofluorescence assay using a monoclonal antibody against 28 kDa envelope protein of WSSV. A convenient method for determining virus titer as MTT(50)/ml was standardized employing the primary hemocyte culture. Expression of viral genes and cellular immune genes were also investigated. The cell culture could be demonstrated for determining toxicity of a management chemical (benzalkonium chloride) by determining its IC(50). The primary hemocyte culture could serve as a model for WSSV titration and viral and cellular immune related gene expression and also for investigations on cytotoxicity of aquaculture drugs and chemicals.

  4. Use of in vitro assays to assess the potential antiproliferative and cytotoxic effects of saffron (Crocus sativus L. in human lung cancer cell line

    Directory of Open Access Journals (Sweden)

    Saeed Samarghandian


    Full Text Available Background: Saffron is harvested from the dried, dark red stigmas of Crocus sativus flowers. It is used as a spice for flavoring and coloring food as a perfume. It is often used for treating several diseases. We investigated the potential of the ethanolic extract of saffron to induce antiproliferative and cytotoxic effects in cultured carcinomic human alveolar basal epithelial cells in comparison with non-malignant (L929 cells. Materials and Methods: Both cells were cultured in Dulbecco′s modified Eagle′s medium and treated with the ethanolic extract of saffron at various concentrations for two consecutive days. Our study resulted in sequences of events marked by apoptosis, such as loss of cell viability, morphology changes that were evaluated by MTT assay and invert-microscope, respectively. Results: The results showed that the ethanolic extract of saffron decreased cell viability in malignant cells as a concentration and time-dependent manner. The IC 50 values against the lung cancer cell line were determined as 1500 and 565 μg/ml after 24 and 48 h, respectively. However, the extract at different concentrations could not significantly decrease the cell viability in L929 cells. Morphology of MCF7 cells treated with the ethanolic extract confirmed the MTT results. Conclusion: We also showed that even higher concentrations of saffron is safe for L929, but the extract exerts pro-apoptotic effects in a lung cancer-derived cell line and could be considered as a potential chemotherapeutic agent in lung cancer.

  5. Antibody-dependent cellular cytotoxicity and skin disease

    Energy Technology Data Exchange (ETDEWEB)

    Norris, D.A.; Lee, L.A.


    Antibody dependent cellular cytotoxicity (ADCC) is a recently described mechanism of immunologic lysis in which cellular targets sensitized by specific antibodies are efficiently and selectively lysed by Fc receptor (FcR) bearing nonspecific effectors. Immunoglobulins of various classes (IgG, IgM, IgA, IgE) and various cellular effectors (large granular lymphocytes, monocyte/macrophages, T lymphocytes, neutrophils, and eosinophils) can induce ADCC in vitro, and the importance of ADCC in vivo is being tested experimentally in resistance to viral, bacterial, and parasitic infection, in tumor surveillance, in allograft rejection, and in inflammatory diseases. There is much indirect evidence that ADCC may be the mechanism of damage of different cellular targets in skin diseases, but the best direct evidence concerns immunologic keratinocyte damage, especially in cutaneous lupus erythematosus (LE). The authors have shown that keratinocytes of several species are highly susceptible to lymphocyte and monocyte-mediated ADCC, but not to neutrophil or eosinophil ADCC in vitro using two different cytotoxicity assays. In contrast, complement was a relatively ineffective mediator of lysis of metabolically intact keratinocyte targets. Patients with certain cutaneous lupus syndromes have serum antibodies capable of inducing monocyte and lymphocyte ADCC of targets coated with extractable nuclear antigens. The authors have shown that these antigens apparently move to the cell membrane of keratinocytes in vitro following ultraviolet irradiation. In an animal model, they have shown that antibodies to SSA/Ro bind to human keratinocytes in vivo, especially after ultraviolet irradiation.

  6. Acute myeloid leukemia (AML)-reactive cytotoxic T lymphocyte clones rapidly expanded from CD8(+) CD62L((high)+) T cells of healthy donors prevent AML engraftment in NOD/SCID IL2Rgamma(null) mice. (United States)

    Distler, Eva; Wölfel, Catherine; Köhler, Sylvia; Nonn, Marion; Kaus, Nina; Schnürer, Elke; Meyer, Ralf G; Wehler, Thomas C; Huber, Christoph; Wölfel, Thomas; Hartwig, Udo F; Herr, Wolfgang


    Current in vitro techniques for isolating leukemia-reactive cytotoxic T lymphocytes (CTLs) from healthy donors are of relatively low efficiency and yield responder populations with unknown biological significance. This study aimed at the development of a more reliable approach, allowing generation and expansion of acute myeloid leukemia (AML)-reactive CTLs using primary in vitro stimulation. We established allogeneic mini-mixed lymphocyte-leukemia cultures (mini-MLLCs) by stimulating donor CD8(+) T cells with human leukocyte antigen (HLA) class I-matched AML blasts in microtiter plates. Before culture, CD8(+) T cells were separated into CD62L((high)+) and CD62L((low)+/neg) subsets enriched for naive/central memory and effector memory cells, respectively. In eight different related and unrelated donor/AML pairs, numerous CTL populations were isolated that specifically lysed myeloid leukemias in association with various HLA-A, -B, or -C alleles. These CTLs expressed T-cell receptors of single Vbeta-chain families, indicating their clonal origin. The majority of CTL clones were obtained from mini-MLLCs initiated with CD62L((high)+) cells. Using antigen-specific stimulation, multiple CTL populations were amplified to 10(8)-10(10) cells within 6 to 8 weeks. Three of four representative CTL clones were capable of completely preventing engraftment of human primary AML blasts in nonobese diabetic/severe combined immune deficient IL2Rgamma(null) mice. The mini-MLLC approach allows the efficient in vitro expansion of AML-reactive CTL clones from CD8(+)CD62L((high)+) precursors of healthy donors. These CTLs can inhibit leukemia engraftment in immunodeficient mice, suggesting their potential biological relevance.

  7. Altered effector function of peripheral cytotoxic cells in COPD

    Directory of Open Access Journals (Sweden)

    Corne Jonathan M


    Full Text Available Abstract Background There is mounting evidence that perforin and granzymes are important mediators in the lung destruction seen in COPD. We investigated the characteristics of the three main perforin and granzyme containing peripheral cells, namely CD8+ T lymphocytes, natural killer (NK; CD56+CD3- cells and NKT-like (CD56+CD3+ cells. Methods Peripheral blood mononuclear cells (PBMCs were isolated and cell numbers and intracellular granzyme B and perforin were analysed by flow cytometry. Immunomagnetically selected CD8+ T lymphocytes, NK (CD56+CD3- and NKT-like (CD56+CD3+ cells were used in an LDH release assay to determine cytotoxicity and cytotoxic mechanisms were investigated by blocking perforin and granzyme B with relevant antibodies. Results The proportion of peripheral blood NKT-like (CD56+CD3+ cells in smokers with COPD (COPD subjects was significantly lower (0.6% than in healthy smokers (smokers (2.8%, p +CD3- cells from COPD subjects were significantly less cytotoxic than in smokers (16.8% vs 51.9% specific lysis, p +CD3+ cells (16.7% vs 52.4% specific lysis, p +CD3- and NKT-like (CD56+CD3+ cells from smokers and HNS. Conclusion In this study, we show that the relative numbers of peripheral blood NK (CD56+CD3- and NKT-like (CD56+CD3+ cells in COPD subjects are reduced and that their cytotoxic effector function is defective.

  8. Evaluation of radio-induced DNA damage and their repair in human lymphocytes by comet assay or single cell gel electrophoresis; Avaliacao do dano radioinduzido no DNA e reparo em linfocitos humanos pelo metodo do cometa (single cell gel electrophoresis)

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Patricia A. do; Suzuki, Miriam F.; Okazaki, Kayo [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)


    The comet assay, also called single cell gel electrophoresis technique, permits to evaluate quantitatively DNA breakage induced by chemical and physical agents at the level of the single cell. The present paper refers to the construction of dose-response curves to DNA damage and repair studies in human peripheral lymphocytes, utilizing the comet assay for the radiosensitivity analysis. So, the blood samples were obtained from healthy donors (40-50 year old), irradiated in a {sup 60} Co source (GAMMACEL 220) with doses of 0.17, 0.25, 0.57, 1.10, 2.12 and 4.22 Gy (0.59 Gy/min.) and processed 1 and 24 hours after the exposition. Results obtained showed a increase in the total lenght of comet (DNA migration) as a function of radiation dose in samples processed 1 and 24 hours after the treatment. The DNA lesion in irradiated lymphocytes with 4.22 Gy (means value of 101.4 {mu}m) were 3.4 times higher than in the untreated lymphocytes (mean value of 30 {mu}m) instead of 24 hours after the irradiation were 1.5 times higher (mean value of 46.3 {mu}m). This reduction on DNA repair occurred in these cells. It was also possible visualized the presence of subpopulations of the cells with different sensitivity and repair capacity to ionizing radiation in these donors. (author). 8 refs., 3 figs.

  9. Melanoma inhibitor of apoptosis protein (ML-IAP) specific cytotoxic T lymphocytes cross-react with an epitope from the auto-antigen SS56

    DEFF Research Database (Denmark)

    Baek Sørensen, Rikke; Faurschou, Mikkel; Troelsen, Lone;


    A large proportion of melanoma patients host a spontaneous T-cell response specifically against ML-IAP-derived peptides. In this study, we describe that some ML-IAP-specific cytotoxic T cells isolated from melanoma patients cross react with an epitope from the auto-antigen SS56. SS56 is a recently...... described target of autoantibody responses in Sjögren's syndrome (SS) as well as systemic lupus erythematosus (SLE). Here, we describe that SS56 is also an auto-antigen for T cells in SS and SLE. Hence, SS56-specific T cells could readily be detected in circulation and among the infiltrating cells of SLE...... skin lesions. SS56-specific T cells were able to lyse target cells presenting the peptide epitope on the surface. Notably, SS56-specific CD8 T cells isolated from an SS patient cross reacted with the ML-IAP epitope. This early evidence of a target for auto-reactive CTL in SS and SLE patients...

  10. Rapid assessment of repair of ultraviolet DNA damage with a modified host-cell reactivation assay using a luciferase reporter gene and correlation with polymorphisms of DNA repair genes in normal human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Qiao Yawei; Spitz, Margaret R.; Guo Zhaozheng; Hadeyati, Mohammad; Grossman, Lawrence; Kraemer, Kenneth H.; Wei Qingyi


    As DNA repair plays an important role in genetic susceptibility to cancer, assessment of the DNA repair phenotype is critical for molecular epidemiological studies of cancer. In this report, we compared use of the luciferase (luc) reporter gene in a host-cell reactivation (HCR) (LUC) assay of repair of ultraviolet (UV) damage to DNA to use of the chloramphenicol (cat) gene-based HCR (CAT) assay we used previously for case-control studies. We performed both the assays on cryopreserved lymphocytes from 102 healthy non-Hispanic white subjects. There was a close correlation between DNA repair capacity (DRC) as measured by the LUC and CAT assays. Although these two assays had similar variation, the LUC assay was faster and more sensitive. We also analyzed the relationship between DRC and the subjects' previously determined genotypes for four polymorphisms of two nucleotide-excision repair (NER) genes (in intron 9 of xeroderma pigmentosum (XP) C and exons 6, 10 and 23 of XPD) and one polymorphism of a base-excision repair gene in exon 10 of X-ray complementing group 1 (XRCC1). The DRC was significantly lower in subjects homozygous for one or more polymorphisms of the two NER genes than in subjects with other genotypes (P=0.010). In contrast, the polymorphic XRCC1 allele had no significant effect on DRC. These results suggest that the post-UV LUC assay measures NER phenotype and that polymorphisms of XPC and XPD genes modulate DRC. For population studies of the DNA repair phenotype, many samples need to be evaluated, and so the LUC assay has several advantages over the CAT assay: the LUC assay was more sensitive, had less variation, was not radioactive, was easier to perform, and required fewer cryopreserved cells. These features make the LUC-based HCR assay suitable for molecular epidemiological studies.

  11. Epstein-Barr Virus-Induced Gene 3 (EBI3) Blocking Leads to Induce Antitumor Cytotoxic T Lymphocyte Response and Suppress Tumor Growth in Colorectal Cancer by Bidirectional Reciprocal-Regulation STAT3 Signaling Pathway (United States)

    Liang, Yanfang; Chen, Qianqian; Du, Wenjing; Chen, Can; Li, Feifei; Yang, Jingying; Peng, Jianyu; Kang, Dongping; Lin, Bihua; Chai, Xingxing; Zhou, Keyuan; Zeng, Jincheng


    Epstein-Barr virus-induced gene 3 (EBI3) is a member of the interleukin-12 (IL-12) family structural subunit and can form a heterodimer with IL-27p28 and IL-12p35 subunit to build IL-27 and IL-35, respectively. However, IL-27 stimulates whereas IL-35 inhibits antitumor T cell responses. To date, little is known about the role of EBI3 in tumor microenvironment. In this study, firstly we assessed EBI3, IL-27p28, IL-12p35, gp130, and p-STAT3 expression with clinicopathological parameters of colorectal cancer (CRC) tissues; then we evaluated the antitumor T cell responses and tumor growth with a EBI3 blocking peptide. We found that elevated EBI3 may be associated with IL-12p35, gp130, and p-STAT3 to promote CRC progression. EBI3 blocking peptide promoted antitumor cytotoxic T lymphocyte (CTL) response by inducing Granzyme B, IFN-γ production, and p-STAT3 expression and inhibited CRC cell proliferation and tumor growth to associate with suppressing gp130 and p-STAT3 expression. Taken together, these results suggest that EBI3 may mediate a bidirectional reciprocal-regulation STAT3 signaling pathway to assist the tumor escape immune surveillance in CRC. PMID:27247488

  12. Eliciting cytotoxic T lymphocytes against acute myeloid leukemia-derived antigens: evaluation of dendritic cell-leukemia cell hybrids and other antigen-loading strategies for dendritic cell-based vaccination. (United States)

    Galea-Lauri, Joanna; Darling, David; Mufti, Ghulam; Harrison, Phillip; Farzaneh, Farzin


    Dendritic cells (DC) have been successfully used in clinical pilot studies to induce tumor-specific immunity as well as clinical response in selected patients. However, DC-based immunotherapy remains a challenge and several parameters need to be examined in order to optimize the induction of anti-tumor immune responses. This study focuses on DC vaccination for leukemia and evaluates the in vitro efficacy of three different strategies for generating antigen-loaded DC-based vaccines for the induction of major histocompatibility complex (MHC) class I-restricted anti-leukemia cytotoxic T lymphocyte (CTL) responses. These included direct fusion of DC with leukemia cells to generate DC-leukemia cell hybrids, and DC pulsed with either apoptotic leukemia cell fragments or whole tumor cell lysates. Using either the U937 cell line or primary human acute myeloid leukemia blasts (AML), DC-leukemia cell hybrids were found to be the most potent in vitro inducers of CTL activity. DC pulsed with apoptotic tumor cell fragments were less efficient, but induced a more potent CTL response compared to tumor lysate-pulsed DC. The CTL responses were both MHC class I-restricted and antigen-specific, as shown by the inability of the CTL to lyse other control targets. The data presented here suggest that the method of antigen loading onto DC may be critical in the design of tumor vaccines.

  13. DNA and Modified Vaccinia Virus Ankara Vaccines Encoding Multiple Cytotoxic and Helper T-Lymphocyte Epitopes of Human Immunodeficiency Virus Type 1 (HIV-1) Are Safe but Weakly Immunogenic in HIV-1-Uninfected, Vaccinia Virus-Naive Adults (United States)

    Newman, Mark J.; deCamp, Allan; Hay, Christine Mhorag; De Rosa, Stephen C.; Noonan, Elizabeth; Livingston, Brian D.; Fuchs, Jonathan D.; Kalams, Spyros A.; Cassis-Ghavami, Farah L.


    We evaluated a DNA plasmid-vectored vaccine and a recombinant modified vaccinia virus Ankara vaccine (MVA-mBN32), each encoding cytotoxic and helper T-lymphocyte epitopes of human immunodeficiency virus type 1 (HIV-1) in a randomized, double-blinded, placebo-controlled trial in 36 HIV-1-uninfected adults using a heterologous prime-boost schedule. HIV-1-specific cellular immune responses, measured as interleukin-2 and/or gamma interferon production, were induced in 1 (4%) of 28 subjects after the first MVA-mBN32 immunization and in 3 (12%) of 25 subjects after the second MVA-mBN32 immunization. Among these responders, polyfunctional T-cell responses, including the production of tumor necrosis factor alpha and perforin, were detected. Vaccinia virus-specific antibodies were induced to the MVA vector in 27 (93%) of 29 and 26 (93%) of 28 subjects after the first and second immunizations with MVA-mBN32. These peptide-based vaccines were safe but were ineffective at inducing HIV-1-specific immune responses and induced much weaker responses than MVA vaccines expressing the entire open reading frames of HIV-1 proteins. PMID:22398243

  14. Maintenance or Emergence of Chronic Phase Secondary Cytotoxic T Lymphocyte Responses after Loss of Acute Phase Immunodominant Responses Does Not Protect SIV-Infected Rhesus Macaques from Disease Progression

    Directory of Open Access Journals (Sweden)

    M. Shannon Keckler


    Full Text Available The simian immunodeficiency virus- (SIV- infected rhesus macaque is the preferred animal model for vaccine development, but the correlates of protection in this model are not completely understood. In this paper, we document the cytotoxic T lymphocyte (CTL response to SIV and its effects on viral evolution in an effort to identify events associated with disease progression regardless of MHC allele expression. We observed the evolution of epitopes targeted by CTLs in a group of macaques that included long-term nonprogressing (LTNP, slowly progressing (SP, normally progressing (NP, and rapidly progressing (RP animals. Collectively, our data (1 identify novel CTL epitopes from an SP animal that are not restricted by known protective alleles, (2 illustrate that, in this small study, RP and NP animals accrue more mutations in CTL epitopes than in SP or LTNP macaques, and (3 demonstrate that the loss of CTL responses to immunodominant epitopes is associated with viral replication increases, which are not controlled by secondary CTL responses. These findings provide further evidence for the critical role of the primary cell-mediated immune responses in the control of retroviral infections.

  15. HIV感染中的特异性细胞毒T淋巴细胞反应若干研究%The specific cytotoxic T-lymphocyte responses in HIV-1 infection

    Institute of Scientific and Technical Information of China (English)



    HIV特异性细胞毒T淋巴细胞(cytotoxic T lymphocyte,CLT)反应对于控制HIV感染和研制艾滋病疫苗发挥着重要作用.随着检测水平的提高,如Elispot、四聚体技术、细胞内因子染色技术的应用,人们逐渐确定了HIV感染者特异性CYL识别的表位和它们的限制性MHC-Ⅰ类基因型.目前人们认为HIV特异性CTL反应是机体抗HIV感染,控制病毒血症的主要机制.本文就近年CTL反应的检测技术、CTL反应在疫苗中的应用、高效抗逆转录病毒治疗(HAART)对细胞免疫的影响以及HIV感染中特异性CTL表位的研究进行综述.

  16. Frequency analysis of simian virus 40-specific cytotoxic T lymphocyte precursors in the high responder C57BL/6 mouse strain. (United States)

    Jennings, S R; Fresa, K L; Lippe, P A; Milici, J E; Tevethia, S S


    Studies in this laboratory have shown that long term simian virus 40 (SV40)-specific cytolytic T lymphocyte (CTL) cultures established from the spleens of high responder C57BL/6 (B6; H-2b) mice exhibit a preference for the selection of H-2Db-restricted CTL clones. In this study, we have investigated the basis for this selection. Limiting dilution cultures were established using responder cells from the popliteal lymph nodes and the spleens of B6 mice immunized subcutaneously in the hind footpads or via the intraperitoneal route, respectively, with syngeneic SV40-transformed cells expressing a full length (1 to 708 amino acid residues) SV40 large T antigen. The relative frequency of CTL precursors (CTLp) able to expand in vitro in the presence of SV40-transformed stimulator cells and interleukin 2 and exhibit lytic activity against H-2b cells expressing full length T antigen ranged from 1/1900 to 1/15,000 in the popliteal lymph node and from 1/8000 to 1/55,000 in the spleen. In these two experimental systems, CTLp restricted to H-2Kb were apparently present at higher frequency than H-2Db-restricted CTLp. Furthermore, CTLp recognizing determinants within the amino-terminal or carboxy-terminal halves of T antigen were generated in approximately equal numbers. The relative affinity of SV40-specific CTL, assessed by inhibition with anti-Lyt 2 monoclonal antibody, indicated that CTL restricted to H-2Db interacted with their target with greater affinity than CTL restricted to H-2Kb. These data suggest that the predominance of isolation of H-2Db-restricted CTL clones from long term in vitro cultures may be a function of the relative affinity of this population as a whole, rather than due to the immunodominance of this subpopulation during the in vivo response to SV40 T antigen.

  17. Effects of benzene inhalation on lymphocyte subpopulations and immune response in mice. (United States)

    Aoyama, K


    To clarify the immunotoxicity of benzene, the effects of benzene inhalation on T and B lymphocytes and immune responses in mice were examined. BALB/c male mice were exposed to 50 or 200 ppm benzene vapor, 6 hr/day for 7 or 14 consecutive days. T and B lymphocytes, in blood and spleen, were detected by the cytotoxicity assay with anti-Thy-1.2 monoclonal antibody and the membrane immunofluorescence test with anti-immunoglobulin antibody, respectively. Humoral immune response to sheep red blood cells was determined by the hemolytic plaque-forming cell assay. Cell-mediated immune response was measured by contact sensitivity (CS) to picryl chloride. The activity of suppressor cells was evaluated in spleen by the suppressive effect on passive transfer of CS. The ratio and absolute number of T and B lymphocytes in blood and spleen were depressed after a 7-day exposure at 50 ppm benzene. The depression of B lymphocytes was dose dependent and more intense than that of T lymphocytes. The ability to form antibodies was suppressed by benzene at all exposure levels, but the CS response was resistant to benzene inhalation and rather enhanced at 200 ppm exposure for 14 days. The activity of suppressor cells could not be detected at this dose level. These data show that benzene inhalation effects on humoral and cell-mediated immune responses are a result of the selective toxicity of benzene to B lymphocytes and suppressor T cells.

  18. Detailed analysis of immunologic effects of the cytotoxic T lymphocyte-associated antigen 4-blocking monoclonal antibody tremelimumab in peripheral blood of patients with melanoma

    Directory of Open Access Journals (Sweden)

    Gualberto Antonio


    Full Text Available Abstract Background CTLA4-blocking antibodies induce tumor regression in a subset of patients with melanoma. Analysis of immune parameters in peripheral blood may help define how responses are mediated. Methods Peripheral blood from HLA-A*0201-positive patients with advanced melanoma receiving tremelimumab (formerly CP-675,206 at 10 mg/kg monthly was repeatedly sampled during the first 4 cycles. Samples were analyzed by 1 tetramer and ELISPOT assays for reactivity to CMV, EBV, MART1, gp100, and tyrosinase; 2 activation HLA-DR and memory CD45RO markers on CD4+/CD8+ cells; and 3 real-time quantitative PCR of mRNA for FoxP3 transcription factor, preferentially expressed by T regulatory cells. The primary endpoint was difference in MART1-specific T cells by tetramer assay. Immunological data were explored for significant trends using clustering analysis. Results Three of 12 patients eligible for immune monitoring had tumor regression lasting > 2 years without relapse. There was no significant change in percent of MART1-specific T cells by tetramer assay. Additionally, there was no generalized trend toward postdosing changes in other antigen-specific CD8+ cell populations, FoxP3 transcripts, or overall changes in surface expression of T-cell activation or memory markers. Unsupervised hierarchical clustering based on immune monitoring data segregated patients randomly. However, clustering according to T-cell activation or memory markers separated patients with clinical response and most patients with inflammatory toxicity into a common subgroup. Conclusion Administration of CTLA4-blocking antibody tremelimumab to patients with advanced melanoma results in a subset of patients with long-lived tumor responses. T-cell activation and memory markers served as the only readout of the pharmacodynamic effects of this antibody in peripheral blood. Clinical trial registration number NCT00086489

  19. Assessment of cytotoxicity of carbon nanoparticles using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) cell viability assay. (United States)

    Schrand, Amanda M; Lin, Jonathan B; Hussain, Saber M


    Ever since the discovery of carbon nanotubes, there has been an increasing interest in technologies that rely upon these incredibly small particles for their unique properties. However, assessment of their biological consequences has been riddled with assay limitations. Here, we describe application of a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium cell viability assay to study cytotoxicity of various carbon-based nanomaterials on cells and discuss some pitfalls of this method.

  20. Genotoxic effects of bistratene A on human lymphocytes. (United States)

    Rojas, E; Valverde, M; Vega, L; Salvador, A; Ramirez, P; Herrera, L A; Watters, D; Lavin, M F; Ostrosky-Wegman, P


    Bistratene A, a toxin isolated from the colonial ascidian Lissoclinum bistratum causes a decrease in mitotic index and retardation of lymphocyte proliferation kinetics when it is added at 48 h to 72-h human lymphocyte cultures. In the same cultures, the incidence of sister chromatid exchanges was not altered by this compound. We also observed an increase in the number of polyploid cells in the cultures, and alterations of the beta-tubulin organization by immunocytochemistry with an antibody against beta-tubulin. Bistratene A induces DNA damage in a dose-dependent fashion in leukocytes, as measured by the alkaline single cell gel electrophoresis assay. These results show that bistratene A interferes with microtubule assembly, is cytotoxic and cytostatic, and that it causes DNA damage.

  1. Linfocitos T citotóxicos CD8+ en la leishmaniasis cutánea CD8+ cytotoxic lymphocytes in cutaneous leishmaniasis

    Directory of Open Access Journals (Sweden)

    Joselín Hernández-Ruiz


    Full Text Available OBJETIVO: Examinar la bibliografía relacionada con la participación de los linfocitos T CD8+ en la reacción inmunitaria a especies de Leishmania causantes de leishmaniasis cutánea. En esta enfermedad se ha resaltado la intervención de macrófagos, células dendríticas, NK y células T CD4+; sin embargo, es poco lo que se conoce de las células T CD8+. Los trabajos en modelos murinos señalan que la participación de las células CD8+ sucede a través de la producción de IFN-gamma, aunque su capacidad citotóxica puede desempeñar una función importante, como lo demuestran los hallazgos en seres humanos. La forma como se activan las células citotóxicas CD8+ es un enigma. Es posible que las células dendríticas realicen esa labor a través de mecanismos que incluyen transpresentación de antígenos. Comprender la contribución de este subtipo celular en la respuesta inmunitaria a Leishmania aportará novedosos conocimientos sobre la fisiopatogenia de la leishmaniasis, lo cual hará posible desarrollar nuevos enfoques terapéuticos para esta parasitosis.OBJECTIVE: Review of the literature on the role of CD8+ T cell in the immune response against Leishmania species that cause cutaneous leishmaniasis. The role of macrophages, dendritic cells, CD4 T cells and NK cells has been extensively analyzed in leishmaniasis, yet very little knowledge has been gained on CD8+ T cells in this disease. Murine models of leishmaniasis suggest that CD8+ T cells participate through IFNg production, yet their cytotoxic capacity may also play a crucial role, as has been found in human disease. It is an enigma what mechanisms underlie the CD8+ T cell activation. It is possible that dendritic cells activate CD8+ T cells through mechanisms that include antigen traspresentation. A better understanding of CD8+ T cells in the immune response against Leishmania will undoubtedly provide new insights into the physiopathogenesis of the disease that could lead to new

  2. Analysis of Epstein-Barr viral DNA load, EBV-LMP2 specific cytotoxic T-lymphocytes and levels of CD4+CD25+T cells in patients with nasopharyngeal carcinomas positive for IgA antibody to EBV viral capsid antigen

    Institute of Scientific and Technical Information of China (English)

    MO Wu-ning; TANG An-zhou; ZHOU Ling; HUANG Guang-wu; WANG Zhan; ZENG Yi


    Background Epstein-Barr virus (EBV) is a herpesvirus commonly associated with several malignant diseases including nasopharyngeal carcinoma (NPC), which is a common cancer in Southeastem Asia. Previous studies showed that plasma levels of EBV-DNA might be a sensitive and reliable biomarker for the diagnosis, staging and evaluating of therapy for NPC. There are a few analyses of the levels of EBV-latent membrane protein 2 (LMP2)-specific cytotoxic T-lymphocytes (CTLs) in patients with NPC. This study was conducted to investigate the levels of EBV-LMP2-specific CTLs, EBV-DNA load and the level of CD4+CD25+T cells in such patients.Methods From February 2006 to April 2006, 62 patients with NPC, 40 healthy virus carders positive for EBV viral capsid antigen (EBV-IgA-VCA) and 40 controls were enrolled in the study. We used a highly sensitive ELISPOT assay,real-time polymerase chain reaction (PCR) and flow cytometry to measure the EBV-LMP2-specific CTL response, the EBV DNA load and the level of CD4+CD25+T cells, respectively.Results The EBV-LMP2-specific CTL responses of the samples from the control, healthy virus carders and patients with NPC were significantly different from the LMP2 epitopes, with the control and healthy virus carder samples displaying a stronger response in three cases. There were significant differences in EBV DNA load in serum between NPC and the healthy groups; patients with NPC at stages Ⅲ or Ⅳ had significantly higher viral loads compared with those at stages Ⅰ or Ⅱ. A significantly higher percentage of CD4+CD25+ T lymphocytes were detected in the patients, compared with healthy virus carriers and healthy controls. Moreover, patients with advanced stages of NPC (Ⅲ and Ⅲ) had significantly higher percentages than the patients with early stages (Ⅰ and Ⅱ).Conclusions Patients with NPC are frequently unable to establish or maintain sufficient immunosurveillance to control proliferating B cells harboring EBV and to destroy the tumor

  3. Evaluation of the antigenotoxic effects of the royal sun mushroom, agaricus brasiliensis (Higher basidiomycetes) in human lymphocytes treated with thymol in the comet assay

    NARCIS (Netherlands)

    Radaković, Milena; Stevanović, Jevrosima; Soković, Marina; Radović, Dejan; Griensven, Van Leo J.L.D.; Stanimirović, Zoran


    The aim of this investigation was to evaluate the possible protective activity of Agaricus brasiliensis (=A. blazei sensu Murrill) ethanol extract against thymol-induced DNA damage in human lymphocytes. Before we studied the possible interaction of thymol and A. brasiliensis extract, each compone

  4. Occupational exposure to cytostatic/antineoplastic drugs and cytogenetic damage measured using the lymphocyte cytokinesis-block micronucleus assay: A systematic review of the literature and meta-analysis. (United States)

    Villarini, M; Gianfredi, V; Levorato, S; Vannini, S; Salvatori, T; Moretti, M

    Many studies have reported the occurrence of work-environment contamination by antineoplastic drugs (ANPD), with significant incorporation of trace amounts of these hazardous drugs in hospital personnel. Given the ability of most ANPD to actively bind DNA, thus inducing genotoxic effects, it is of pivotal importance to assess the degree of genotoxic damage (i.e., residual genotoxic risk) in occupationally exposed subjects. The lymphocyte cytokinesis-block micronucleus (L-CBMN) assay is largely used for biological effect monitoring in subjects occupationally exposed to ANPD. In this study, we identified and analyzed the studies published reporting the use of the L-CBMN assay as biomarker of genotoxic risk in health care workers exposed to ANPD with the aim of performing meta-analysis and providing a meta-estimate of the genotoxic effect of exposure. We retrieved 24 studies, published from 1988 to 2015, measuring MN in peripheral blood lymphocytes in health care workers occupationally exposed to ANPD. In 15 out of the 24 studies (62.5%), increased MN frequencies were recognized in exposed subjects as compared to controls. The meta-analysis of MN frequency of the combined studies confirmed an association between occupational exposure to ANPD and cytogenetic effects with an overall meta-estimate of 1.67 [95% CI: 1.41-1.98]. In 16 out of the 24 studies (66.6%) at least one other genotoxicity biomarker, besides L-CBMN assay, was employed for biological effect monitoring. In several studies the effect of exposure to ANPD was evaluated also in terms of MN in exfoliated buccal cells. Other studies focused on genotoxicity endpoints, such as sister chromatid exchanges (3 studies), chromosome aberrations (6 studies), or primary DNA damage investigated by comet assay (7 studies). Overall, there was good agreement between other genotoxicity tests employed and L-CBMN assay outcomes. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Deep immune profiling by mass cytometry links human T and NK cell differentiation and cytotoxic molecule expression patterns. (United States)

    Bengsch, Bertram; Ohtani, Takuya; Herati, Ramin Sedaghat; Bovenschen, Niels; Chang, Kyong-Mi; Wherry, E John


    The elimination of infected or tumor cells by direct lysis is a key T and NK cell effector function. T and NK cells can kill target cells by coordinated secretion of cytotoxic granules containing one or both pore-forming proteins, perforin and granulysin and combinations of granzyme (Gzm) family effector proteases (in humans: Gzm A, B, K, M and H). Understanding the pattern of expression of cytotoxic molecules and the relationship to different states of T and NK cells may have direct relevance for immune responses in autoimmunity, infectious disease and cancer. Approaches capable of simultaneously evaluating expression of multiple cytotoxic molecules with detailed information on T and NK differentiation state, however, remain limited. Here, we established a high dimensional mass cytometry approach to comprehensively interrogate single cell proteomic expression of cytotoxic programs and lymphocyte differentiation. This assay identified a coordinated expression pattern of cytotoxic molecules linked to CD8 T cell differentiation stages. Coordinated high expression of perforin, granulysin, Gzm A, Gzm B and Gzm M was associated with markers of late effector memory differentiation and expression of chemokine receptor CX3CR1. However, classical gating and dimensionality reduction approaches also identified other discordant patterns of cytotoxic molecule expression in CD8 T cells, including reduced perforin, but high Gzm A, Gzm K and Gzm M expression. When applied to non-CD8 T cells, this assay identified different patterns of cytotoxic molecule co-expression by CD56(hi) versus CD56(dim) defined NK cell developmental stages; in CD4 T cells, low expression of cytotoxic molecules was found mainly in TH1 phenotype cells, but not in Tregs or T follicular helper cells (TFH). Thus, this comprehensive, single cell, proteomic assessment of cytotoxic protein co-expression patterns demonstrates specialized cytotoxic programs in T cells and NK cells linked to their differentiation

  6. In vitro cytotoxicity against Marek's disease lymphoblastoid cell lines after enzymatic removal of Marek's disease tumor-associated surface antigen.


    Schat, K A; Murthy, K K


    Marek's disease tumor-associated surface antigen (MATSA) has been claimed to be the target of cytotoxic lymphocytes in in vitro tests for Marek's disease immunity. Treatment with papain, but not with trypsin or mixed glycosidases, removed MATSA from certain Marek's disease lymphoblastoid cell lines. Tumor cells with and without MATSA were used as target cells for in vitro studies on cell-mediated immune responses with sensitized spleen cells in a chromium release assay. The removal of MATSA d...

  7. CTLA-4基因单倍型与吸毒合并HIV感染的相关性研究%Association between Cytotoxic T Lymphocyte-associated Antigen 4 Gene Haplotype and Drug Abuse with HIV Infection

    Institute of Scientific and Technical Information of China (English)

    刘莹; 刁波; 申元英; 周芳; 冯勇; 罗凡; 侯炜


    目的 研究细胞毒T淋巴细胞相关抗原4(cytotoxic T lymphocyte associated antigen-4,CTLA-4)基因外显子1的49位点和启动子-318位点单倍型与吸毒合并HIV感染的相关性.方法 采用序列特异性引物聚合酶链反应(polymeriase chain reaction with sequence-specific primers,PCR-SSP)方法,检测24例单纯吸毒者、41例吸毒合并HIV感染患者以及204例正常对照者CTLA-4基因外显子1的49位点启动子-318位点的单倍型.结果 吸毒者中CTLA-4A+ 49G和C-318T单倍型与正常对照组间差异无统计学意义(P>0.05).吸毒合并HIV感染组中CTLA-4单倍型1.1(C-318-A+ 49/C-318-A+ 49)显著低于对照组(2.4%vs 13.2%,P<0.05);CTLA-4单倍型3.3(T-318-A+ 49/T-318-A+49)明显高于对照组(12.2%vs2.9%,P<0.01).与吸毒组比较,吸毒合并HIV感染组中CTLA-4单倍型1.1(C-318-A十49/C-318-A+ 49)显著下降(2.4% vs 12.5%,P<0.05).结论 吸毒合并HIV感染与CTLA-4基因动态密切相关,单倍型1.1与吸毒合并HIV感染呈负相关,单倍型3.3与吸毒合并HIV感染呈正相关.%Objective To investigate the association between the haplotype of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and drug abuse with HIV infection. Methods The A + 49G transition polymorphism at position 49 (exon 1) and C-318T transition polymorphism at position 318 in the promoter of the CTLA-4 gene were determined by polymerase chain reaction with sequence specific primers (PCR-SSP) method in 24 drug abusers, 41 drug abusers with HIV infection and 204 healthy controls. Results Compared with the control group, no significant difference in the distribution of haplotype was observed in A + 49G and C-318T gene polymorphisms in drug abusers (P>0. 05), the frequency of haplotype 1. 1 (C-318-A + 49/C-318-A + 49) in drug abusers with HIV infection was significantly lower (2. 4% vs 13. 2%, P<0. 05), and the frequency of haplotype 3. 3 (T-318-A + 49/T-318-A + 49) was significantly higher (12. 2% vs 2. 9%, P<0. 01

  8. Antiproliferative, Cytotoxic, and Apoptotic Activity of Steroidal Oximes in Cervicouterine Cell Lines

    Directory of Open Access Journals (Sweden)

    Luis Sánchez-Sánchez


    Full Text Available Steroidal sapogenins have shown antiproliferative effects against several tumor cell lines; and their effects on human cancer cells are currently under study. Changes in the functionality on the steroidal structure make it possible to modify the biological activity of compounds. Herein, we report the synthesis and in vitro antitumor activity of two steroidal oxime compounds on cervical cancer cells. These derivatives were synthesized from the steroidal sapogenin diosgenin in good yields. The in vitro assays show that the steroidal oximes show significant antiproliferative activity compared to the one observed for diosgenin. Cell proliferation, cell death, and the cytotoxic effects were determined in both cervical cancer cells and human lymphocytes. The cancer cells showed apoptotic morphology and an increased presence of active caspase-3, providing the notion of a death pathway in the cell. Significantly, the steroidal oximes did not exert a cytotoxic effect on lymphocytes.

  9. Crystal structure of swine major histocompatibility complex class I SLA-1 0401 and identification of 2009 pandemic swine-origin influenza A H1N1 virus cytotoxic T lymphocyte epitope peptides. (United States)

    Zhang, Nianzhi; Qi, Jianxun; Feng, Sijia; Gao, Feng; Liu, Jun; Pan, Xiaocheng; Chen, Rong; Li, Qirun; Chen, Zhaosan; Li, Xiaoying; Xia, Chun; Gao, George F


    The presentation of viral epitopes to cytotoxic T lymphocytes (CTLs) by swine leukocyte antigen class I (SLA I) is crucial for swine immunity. To illustrate the structural basis of swine CTL epitope presentation, the first SLA crystal structures, SLA-1 0401, complexed with peptides derived from either 2009 pandemic H1N1 (pH1N1) swine-origin influenza A virus (S-OIV(NW9); NSDTVGWSW) or Ebola virus (Ebola(AY9); ATAAATEAY) were determined in this study. The overall peptide-SLA-1 0401 structures resemble, as expected, the general conformations of other structure-solved peptide major histocompatibility complexes (pMHC). The major distinction of SLA-1 0401 is that Arg(156) has a "one-ballot veto" function in peptide binding, due to its flexible side chain. S-OIV(NW9) and Ebola(AY9) bind SLA-1 0401 with similar conformations but employ different water molecules to stabilize their binding. The side chain of P7 residues in both peptides is exposed, indicating that the epitopes are "featured" peptides presented by this SLA. Further analyses showed that SLA-1 0401 and human leukocyte antigen (HLA) class I HLA-A 0101 can present the same peptides, but in different conformations, demonstrating cross-species epitope presentation. CTL epitope peptides derived from 2009 pandemic S-OIV were screened and evaluated by the in vitro refolding method. Three peptides were identified as potential cross-species influenza virus (IV) CTL epitopes. The binding motif of SLA-1 0401 was proposed, and thermostabilities of key peptide-SLA-1 0401 complexes were analyzed by circular dichroism spectra. Our results not only provide the structural basis of peptide presentation by SLA I but also identify some IV CTL epitope peptides. These results will benefit both vaccine development and swine organ-based xenotransplantation.

  10. Crystal Structure of Swine Major Histocompatibility Complex Class I SLA-1*0401 and Identification of 2009 Pandemic Swine-Origin Influenza A H1N1 Virus Cytotoxic T Lymphocyte Epitope Peptides ▿ (United States)

    Zhang, Nianzhi; Qi, Jianxun; Feng, Sijia; Gao, Feng; Liu, Jun; Pan, Xiaocheng; Chen, Rong; Li, Qirun; Chen, Zhaosan; Li, Xiaoying; Xia, Chun; Gao, George F.


    The presentation of viral epitopes to cytotoxic T lymphocytes (CTLs) by swine leukocyte antigen class I (SLA I) is crucial for swine immunity. To illustrate the structural basis of swine CTL epitope presentation, the first SLA crystal structures, SLA-1*0401, complexed with peptides derived from either 2009 pandemic H1N1 (pH1N1) swine-origin influenza A virus (S-OIVNW9; NSDTVGWSW) or Ebola virus (EbolaAY9; ATAAATEAY) were determined in this study. The overall peptide–SLA-1*0401 structures resemble, as expected, the general conformations of other structure-solved peptide major histocompatibility complexes (pMHC). The major distinction of SLA-1*0401 is that Arg156 has a “one-ballot veto” function in peptide binding, due to its flexible side chain. S-OIVNW9 and EbolaAY9 bind SLA-1*0401 with similar conformations but employ different water molecules to stabilize their binding. The side chain of P7 residues in both peptides is exposed, indicating that the epitopes are “featured” peptides presented by this SLA. Further analyses showed that SLA-1*0401 and human leukocyte antigen (HLA) class I HLA-A*0101 can present the same peptides, but in different conformations, demonstrating cross-species epitope presentation. CTL epitope peptides derived from 2009 pandemic S-OIV were screened and evaluated by the in vitro refolding method. Three peptides were identified as potential cross-species influenza virus (IV) CTL epitopes. The binding motif of SLA-1*0401 was proposed, and thermostabilities of key peptide–SLA-1*0401 complexes were analyzed by circular dichroism spectra. Our results not only provide the structural basis of peptide presentation by SLA I but also identify some IV CTL epitope peptides. These results will benefit both vaccine development and swine organ-based xenotransplantation. PMID:21900158

  11. Recognition of clonogenic leukemic cells, remission bone marrow and HLA-identical donor bone marrow by CD8+ or CD4+ minor histocompatibility antigen-specific cytotoxic T lymphocytes. (United States)

    Faber, L M; van der Hoeven, J; Goulmy, E; Hooftman-den Otter, A L; van Luxemburg-Heijs, S A; Willemze, R; Falkenburg, J H


    We investigated whether minor histocompatibility (mH) antigen-specific cytotoxic T lymphocytes (CTL) can discriminate between leukemic hematopoietic progenitor cells (leukemic-HPC) from AML or CML patients, the HPC from their remission bone marrow (remission-HPC), and normal HPC from their HLA-identical sibling bone marrow donor (donor-HPC). Specific lysis by CD8+ CTL clones was observed not only of the leukemic-HPC but also of the donor-HPC in 3/4 patient/donor combinations expressing mH antigen HA-1, 3/5 combinations expressing mH antigen HA-2, 2/3 combinations expressing mH antigen HA-3, and 2/2 combinations expressing mH antigen HY-A1. In four patient/donor combinations the recognition of the donor-HPC was clearly less than of the leukemic-HPC, indicating differential susceptibility to lysis by these mH CTL clones. In addition, differential recognition of leukemic-HPC and remission-HPC within seven patients was analyzed. In one patient expressing the HA-2 antigen on the leukemic cells the recognition of the remission-HPC was clearly less than of the leukemic-HPC. One CD4+ CTL clone showed specific lysis of the leukemic-HPC from an AML patient and a CML patient as well as of normal remission-HPC and donor-HPC. These results illustrate that in general CD8+ and CD4+ mH antigen specific CTL clones do not differentially recognize leukemic-HPC and normal-HPC. However, differences in susceptibility to lysis of malignant versus normal cells may contribute to a differential GVL effect.

  12. A database of IC50 values and principal component analysis of results from six basal cytotoxicity assays, for use in the modelling of the in vivo and in vitro data of the EU ACuteTox project. (United States)

    Clothier, Richard; Dierickx, Paul; Lakhanisky, Thaly; Fabre, Myriam; Betanzos, Monica; Curren, Rodger; Sjöström, Michael; Raabe, Hans; Bourne, Nicola; Hernandez, Vanessa; Mainez, Jessica; Owen, Monika; Watts, Sarah; Anthonissen, Roel


    The main aim of the ACuteTox project (part of the EU 6th Framework programme) is to demonstrate that animal tests for acute systemic toxicity can be replaced by alternative in vitro assays. In this project, data for 97 reference chemicals were collected in the AcuBase database, designed to handle deposited in vitro and in vivo (human and animal) data. To demonstrate the applicability of in vitro basal cytotoxicity tests and in vitro-in vivo modelling, it was deemed necessary to obtain data that were generated via defined standard operating procedures. The molar basal cytotoxicity IC50 values (the 50% inhibitory concentrations for the endpoint measured) for a mouse fibroblast cell line (3T3), a human hepatic cell line (HepG2), a rat hepatic cell line (Fa32), and a human neutrophil cell line (HL-60), were compared, and gave an R(2) correlation of 0.83. To identify chemicals that showed differential cytotoxicity to the various cell types involved, principal component analysis (PCA) was undertaken independently, once all the results had been returned. This showed that colchicine, cycloheximide, digoxin, 5-fluorouracil and hexachlorobenzene gave the lowest correlations with the first score vector of the PCA. The results presented are to be used to identify outliers that need to be further studied via the use of tissue-specific in vitro assays.

  13. AFRRI’s Gamma-Ray, X-Ray, and Fission-Neutron Calibration Curves for the Lymphocyte Dicentric Assay: Application of a Metaphase Finder System (United States)


    mature automated metaphase-finding dicentric chromosome is one such aberration, component coupled with lymphocyte- dicentric and it is recognized as a...biomarker of exposures scoring at peripheral, or satellite, scoring sta- to ionizing radiation. Measuring the frequency tions. of dicentric chromosomes ...published reports show that differ- mechanisms of chromosome -aberration forma- ences exist in the measured yield of dicentrics tion (Bauchinger 1983). per Gy

  14. Screening of Indian medicinal plants for cytotoxic activity by Brine Shrimp Lethality (BSL assay and evaluation of their total phenolic content

    Directory of Open Access Journals (Sweden)

    Mahesh Biradi


    Full Text Available Objective: Plant-derived cytotoxic constituents and polyphenolic compounds have played an important role in the development of clinically useful anticancer agents. In this context, we have selected six Indian medicinal plants based on the literature claims and an attempt was made to evaluate the cytotoxic potential and total phenolic content (TPC of their methanol extracts and fractions. Materials and Methods: Six plants have been selected for the study, namely, Artemisia absinthium Linn. (Asteraceae, Oroxylum indicum (Linn. Vent. (Bignoniaceae, Heliotropium indicum Linn. (Boraginaceae, Amorphophallus sylvaticus (Roxb. Kunth. (Araceae, Mimosa pudica Linn. (Mimosaceae, and Premna serratifolia Linn. (Verbenaceae. Authenticated plant materials were subjected to extraction with methanol by cold maceration and hot percolation methods. The extracts were fractionated into four fractions (F1, F2, F3, and F4. Preliminary phytochemical investigation was carried out for all extracts and fractions. All extracts and their fractions were subjected to cytotoxicity screening by brine shrimp lethality (BSL bioassay. The plants with significant cytotoxicity were evaluated for TPC by using Folin-Ciocalteu reagent. Results: F1, F2, and F3 fractions of A. absinthium and P. serratifolia and F1 fraction of M. pudica have shown significant cytotoxicity (lethal concentration (LC 50 < 100 ppm compared with other fractions. F1, F2, and F3 fractions of A. absinthium show the LC 50 values 32.52, 14.27, and 24.02, respectively; F1, F2, and F3 of P. serratifolia show LC 50 values 7.61, 4.01, and 10.91 and same for F1 fraction of M. pudica was 34.82 μg/ml, respectively. TPC was found to be significantly higher (39.11 mg gallic acid equivalent (GAE/g in P. serratifolia compared with other two plants. Conclusion: The cytotoxicity screening system confirmed the proposed anticancer plants used by traditional healers and literature claims.

  15. Evaluation of toxicity of essential oils palmarosa, citronella, lemongrass and vetiver in human lymphocytes. (United States)

    Sinha, Sonali; Jothiramajayam, Manivannan; Ghosh, Manosij; Mukherjee, Anita


    The present investigation was undertaken to study the cytotoxic and genotoxic potential of the essential oils (palmarosa, citronella, lemongrass and vetiver) and monoterpenoids (citral and geraniol) in human lymphocytes. Trypan blue dye exclusion and MTT test was used to evaluate cytotoxicity. The genotoxicity studies were carried out by comet and DNA diffusion assays. Apoptosis was confirmed by Annexin/PI double staining. In addition, generation of reactive oxygen species was evaluated by DCFH-DA staining using flow cytometry. The results demonstrated that the four essential oils and citral induced cytotoxicity and genotoxicity at higher concentrations. The essential oils were found to induce oxidative stress evidenced by the generation of reactive oxygen species. With the exception of geraniol, induction of apoptosis was confirmed at higher concentrations of the test substances. Based on the results, the four essential oils are considered safe for human consumption at low concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Psychoneuroimmunology and natural killer cells: the chromium release whole blood assay. (United States)

    Fletcher, Mary Ann; Barnes, Zachary; Broderick, Gordon; Klimas, Nancy G


    Natural killer (NK) cells are an essential component of innate immunity. These lymphocytes are also sensitive barometers of the effects of endogenous and exogenous stressors on the immune system. This chapter will describe a chromium ((51)Cr) release bioassay designed to measure the target cell killing capacity of NK cells (NKCC). Key features of the cytotoxicity assay are that it is done with whole blood and that numbers of effector cells are determined for each sample by flow cytometry and lymphocyte count. Effector cells are defined as CD3-CD56+ lymphocytes. Target cells are the K562 eyrthroleukemia cell line. Killing capacity is defined as number of target cells killed per effector cell, at an effector cell/target cell ratio of 1:1 during a 4 h in vitro assay.

  17. In Vitro Cytotoxic Activity of the Essential Oil Extracted from Artemisia Absinthium

    Directory of Open Access Journals (Sweden)

    Mahboubeh Taherkhani


    Full Text Available Background: Essential oils are found to have multiple active components which can show in vitro cytotoxic action against various cancerous cell lines. This study reports the in vitro cytotoxic effects of the essential oil from Artemisia absinthium L. (Asteraceae growing wild in Iran. Methods: Water-distilled essential oil of A. absinthium collected from Ardabil, north-western Iran, was examined for its cytotoxic effects using a modified MTT assay. Air-dried aerial parts of A. absinthium was subjected to hydrodistillation using a clevenger-type apparatus. Cytotoxicity of the essential oil was measured against Hela and human healthy peripheral blood cells. Results: The 50% cytotoxic concentrations were found to be 48.59 µg/ml and 5456.07 µg/ml for Hela cells and human lymphocytes, respectively. The volatile oil displayed good cytotoxic action against the human tumor cell line. Conclusion: The IC50 shows that cytotoxicity of the oil against human tumor cell line is much higher than that required for healthy human cells. These results indicate low adverse effects for this oil. The findings of this study necessitate the need for further consideration of this essential oil in anti-neoplastic chemotherapy.

  18. Determination of CD4+ and CD8+ lymphocytes with the cytosphere assay: a comparative study with flow cytometry and the immunoalkaline phosphatase method

    DEFF Research Database (Denmark)

    Gernow, A; Lisse, I M; Böttiger, B;


    number of CD4+ lymphocytes determined by CA showed a good correlation with results obtained by FC (correlation coefficients were 0.92 and 0.74 in Denmark and The Ivory Coast, respectively) and IA (correlation coefficients were 0.94 and 0.66 in Denmark and The Ivory Coast, respectively). However, for HIV......-seronegative samples the corresponding correlation coefficients were low. CD4% determinations deviated more from FC counts at higher CD4 counts than at lower levels for both seronegative and seropositive individuals. In conclusion, the CA performed best for samples from HIV-infected individuals. Before a more general...

  19. Cytotoxic effects of 109 reference compounds on rat H4IIE and human HepG2 hepatocytes. III: Mechanistic assays on oxygen consumption with MitoXpress and NAD(P)H production with Alamar Blue™. (United States)

    Schoonen, Willem G E J; Stevenson, Joe C R; Westerink, Walter M A; Horbach, G Jean


    In vitro toxicity screening can reduce the attrition rate of drug candidates in the pharmaceutical industry in the early development process. The focus in this study is to compare the sensitivity for cytotoxicity of a time-resolved fluoro metric oxygen probe with that of a fluoro metric Alamar Blue™ (AB) assay. Both assays measure mitochondrial activity by either oxygen consumption (LUX-A65N-1 (MitoXpress, Luxcel) probe) or NADH/FADH conversion (AB). Both assays were carried out with increasing concentrations of 109 reference compounds using rat H4IIE and human HepG2 hepatocytes at incubation periods of 24, 48 and 72 h. Prior to this study, the influence on medium with either glucose or galactose was studied to analyze the rate of glycolysis and oxygen consumption, which latter process may be impaired in hepatoma cells. Inhibitors of oxygen consumption in combination with a glucose up-take inhibitor showed the largest consumption rate differences in the presence of 5mM of glucose. The choice for the 109 reference compounds was based on the so-called Multicentre Evaluation for In vitro Cytotoxicity (MEIC) and on diverse drug categories. For 59 toxic reference compounds, an evaluation for both assays was carried up to 10(-3)M. Toxicity was demonstrated with MitoXpress for 23 (39%) and 36 (61%) compounds in H4IIE and HepG2 cells, respectively, and with AB for 44 (75%) and 40 (68%) compounds. For 50 more pharmaceutical drugs more physiological concentrations were used up to 3.16×10(-5)M, and only 19 (38%) of these compounds appeared to be toxic in both assays. In conclusion, overall 63 (58%) and 60 (55%) compounds showed toxic effects with the MitoXpress and AB assays on rat H4IIE and human HepG2 hepatocytes, respectively. AB assays were more sensitive with respect to H4IIE cells and MitoXpress assays with respect to HepG2 cells. At all tested time intervals, MitoXpress showed its sensitivity, while AB is more sensitive at 48 and 72 h. With AB more toxic compounds

  20. Vehicle and positive control values from the in vivo rodent comet assay and biomonitoring studies using human lymphocytes: historical database and influence of technical aspects. (United States)

    Pant, Kamala; Springer, S; Bruce, S; Lawlor, T; Hewitt, N; Aardema, M J


    There is increased interest in the in vivo comet assay in rodents as a follow-up approach for determining the biological relevance of chemicals that are genotoxic in in vitro assays. This is partly because, unlike other assays, DNA damage can be assessed in this assay in virtually any tissue. Since background levels of DNA damage can vary with the species, tissue, and cell processing method, a robust historical control database covering multiple tissues is essential. We describe extensive vehicle and positive control data for multiple tissues from rats and mice. In addition, we report historical data from control and genotoxin-treated human blood. Technical issues impacting comet results are described, including the method of cell preparation and freezing. Cell preparation by scraping (stomach and other GI tract organs) resulted in higher % tail DNA than mincing (liver, spleen, kidney etc) or direct collection (blood or bone marrow). Treatment with the positive control genotoxicant, ethyl methanesulfonate (EMS) in rats and methyl methanesulfonate in mice, resulted in statistically significant increases in % tail DNA. Background DNA damage was not markedly increased when cell suspensions were stored frozen prior to preparing slides, and the outcome of the assay was unchanged (EMS was always positive). In conclusion, historical data from our laboratory for the in vivo comet assay for multiple tissues from rats and mice, as well as human blood show very good reproducibility. These data and recommendations provided are aimed at contributing to the design and proper interpretation of results from comet assays.

  1. Novel Confocal Microscopic and Flow Cytometric Based Assays to Visualize and Detect the (Beta)2-Adrenergic Receptor in Human Lymphocyte and Mononuclear Cell Populations (United States)

    Salicru, A. N.; Crucian, B. E.; Nelman, M. A.; Sams, C. F.; Actor, J. K.; Marshall, G. D.


    The data show that immunophenotyping of leukocyte populations with (beta)2AR is possible with the commercially available Ab, although the FC assay is limited to the IST as a result of the Ab binding site to the intracellular C-terminus of the 2AR. The FC assay has applications for measuring alterations in total (beta)2AR in human leukocyte populations as changes in fluorescence. In addition, CM confirms that both surface and intracellular compartments stain positively for the (beta)2AR and can be used for qualitative assays that screen for changes in receptor compartmentalization and localization.

  2. T细胞功能学与结构免疫学结合方法鉴定HLA-A2限制性的细胞毒性T淋巴细胞表位富集区%Combined Functional and Structural Methods Verification of an Epitope Clustering Region of HLA-A2-restricted Cytotoxic T Lymphocyte

    Institute of Scientific and Technical Information of China (English)

    刘军; 齐建勋; 高峰; 严景华; 高福


    T细胞表位在抗病毒的T细胞免疫中发挥核心作用,目前已在多种病原微生物的蛋白序列上发现存在T细胞表位的聚集现象.本文建立了一套功能学与结构学结合的策略鉴定病原体上细胞毒性T细胞(Cytotoxic T Lymphocyte,CTL)表位富集区的方法,并以严重急性呼吸道综合征(SARS)相关冠状病毒(SARS-CoV)的M蛋白为例,成功地鉴定了一个HLA-A2限制性的表位富集区.首先通过生物信息学的方法预测并合成M蛋白跨膜区的HLA-A2潜在结合多肽,通过体外复性实验和T2细胞结合实验验证多肽与HLA-A2的结合力;然后在HLA-A2.1/Kb转基因小鼠中检测这些多肽的免疫原性;最后通过×射线衍射技术,成功解析了其中一条多肽与HLA-A*0201的复合物结构,其结构显示该多肽具有典型的HLA-A*0201表位的结构特点,但却呈现出与以往鉴定多肽不同的构象和锚定残基.本文对于理解机体对SARS-CoV等病原体产生的T细胞免疫反应,以及为更广泛的人群设计T细胞疫苗具有重要意义.%T cell epitopes play an important role in the anti-virus specific T cell immunity. Currently, the phenomenon of T cell epitope clustering is reported among different pathogenic microbes. Here, a strategy is established to identify Cytotoxic T Lymphocyte (CTL) epitope clusters region with the combined functional and structural methods. And by using this strategy, a HLA-A2 -restricted epitope cluster in SARS-CoV M protein is successfully defined. Firstly, the computer-assisted algorithm was utilized to predict a series of potential HLA -A2 binding peptides around the sequences of two previous identified HLA -A2 epitopes Mn2 and Md3 in the transmembrane domain of SARS-CoV M protein. The HLA-A2 binding affinities of these peptides were accessed through in vitro refolding assay and T2 cell binding assay. Consequently, antigenicity of the peptides was confirmed by ELISPOT by using transgenic mice immunized with

  3. 树突状细胞诱导的细胞毒性T细胞对黑色素瘤的抑制作用%Inhibitory effects of cytotoxic T lymphocyte induced by dendritic cells on melanoma

    Institute of Scientific and Technical Information of China (English)

    张燕; 谭延伟; 蔡建辉; 胡玲玲


    Objective To investigate the role of CD4 + CD25 + regulatory T cell (Treg) in cytotoxic T lymphocyte (CTL) inhibiting B16 melanoma and the mechanism.Methods B16 melanoma cells were injected into subcutaneous tissue under the left shoulder of the C57BL/6 mouse to make the melanoma animal models.Then the animal models were irradiated by 60Co-ray on the total body in order to get a no-marrow lymphocyte deletion (NMLD) state.Eighty C57BL/6 mice were divided into 4 groups:3 experimental groups and a control group,with 20 mice each.In vitro T cells were induced into CTL with tumor specificity.CTL were injected back into the mouse body through the vein in the tail.The changes of tumor volume and tumor weight were observed.Results The tumor inhibition rate in the three experiment groups was 90.89%,92.52% and 60.02% respectively,which was significantly higher than that in the control group (P < 0.05).A significant tumor inhibition was observed in groups A and B with a deletion of CD4 + CD25 + Tregs,in comparison with that in group C with no deletion of Tregs (P < 0.05).But no significant difference was found between groups A and B with deletion of Tregs at different time points (P > 0.05).Conclusion The deletion of CD4 + CD25 + Treg could significantly increase the tumor inhibition effect of antigen-specific CTL in melanoma.%目的 探讨CD4+ CD25+ Treg细胞对树突状细胞(DC)诱导的细胞毒性T细胞(CTL)对B16黑色素瘤抑瘤作用的影响及其机制.方法 制备C57BL/6小鼠B16黑色素瘤动物模型,行全身放疗达非髓性淋巴细胞删除(NMLD)状态.随机将80只小鼠分为4组.A组:在DC与T细胞共同培养前应用免疫磁珠法(MACS)删除CD4+ CD25+ Treg细胞;B组:DC与T细胞共同培养后删除CD4+ CD25+ Treg细胞;C组:DC与T细胞共同培养时不删除CD4+ CD25+ Treg细胞.D组:对照组.体外应用DC诱导T细胞产生效应细胞CTL,将CTL经鼠尾静脉回输小鼠体内,观察对黑色素瘤的抑瘤效果.结果 A

  4. Cytotoxicity and mitogenicity assays with real-time and label-free monitoring of human granulosa cells with an impedance-based signal processing technology intergrating micro-electronics and cell biology. (United States)

    Oktem, Ozgur; Bildik, Gamze; Senbabaoglu, Filiz; Lack, Nathan A; Akin, Nazli; Yakar, Feridun; Urman, Defne; Guzel, Yilmaz; Balaban, Basak; Iwase, Akira; Urman, Bulent


    A recently developed technology (xCelligence) integrating micro-electronics and cell biology allows real-time, uninterrupted and quantitative analysis of cell proliferation, viability and cytotoxicity by measuring the electrical impedance of the cell population in the wells without using any labeling agent. In this study we investigated if this system is a suitable model to analyze the effects of mitogenic (FSH) and cytotoxic (chemotherapy) agents with different toxicity profiles on human granulosa cells in comparison to conventional methods of assessing cell viability, DNA damage, apoptosis and steroidogenesis. The system generated the real-time growth curves of the cells, and determined their doubling times, mean cell indices and generated dose-response curves after exposure to cytotoxic and mitogenic stimuli. It accurately predicted the gonadotoxicity of the drugs and distinguished less toxic agents (5-FU and paclitaxel) from more toxic ones (cisplatin and cyclophosphamide). This platform can be a useful tool for specific end-point assays in reproductive toxicology. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Correlation between the pharmacological efficacy of cyclosporine and tacrolimus as evaluated by the lymphocyte immunosuppressant sensitivity test (LIST) and the MTT assay procedure in patients before and after renal transplantation. (United States)

    Sugiyama, K; Isogai, K; Toyama, A; Satoh, H; Saito, K; Nakagawa, Y; Tasaki, M; Takahashi, K; Hirano, T


    Cyclosporine and tacrolimus are calcineurin inhibitors that are used to prevent acute rejection in renal transplant recipients. The lymphocyte immunosuppressant sensitivity test (LIST) can predict the pharmacological efficacy of these immunosuppressive agents for renal transplant recipients. There is a correlation between cyclosporine and tacrolimus pharmacological efficacy as evaluated by LIST by the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay procedure prior to renal transplantation. However, the LIST can also evaluate patients before and after the transplantation. The present study examined the relationship between cyclosporine and tacrolimus pharmacological efficacy by LIST using the MTT assay in 16 renal transplant recipients at 1, 3 and 12 months after transplantation, as well as before the operation. The relationship of cyclosporine and tacrolimus pharmacological efficacy gave a significant Kendall and Spearman's coefficient correlation in these transplant recipients by the LIST using the MTT assay procedure immediately prior to renal transplantation (rk = 0.711, rs = 0.877, p cyclosporine and tacrolimus IC50 values were also observed with a significant Kendall and Spearman's coefficient correlation at 1 and 12 months after transplantation (rk1month = 0.65, rs1month = 0.829, p transplantation (rk3month = 0.117, rs3month = 0.1, p > 0.05). Both cyclosporine and tacrolimus exhibit pharmacological efficacy by the inhibition of calcineurin. However, the correlation between cyclosporine and tacrolimus pharmacological efficacies may be altered, due to immunosuppressive therapy or clinical events at 3 months after renal transplantation.

  6. Differential induction of apoptosis by type A and B trichothecenes in Jurkat T-lymphocytes. (United States)

    Nasri, Thanakarn; Bosch, Remko R; Voorde, Sandra ten; Fink-Gremmels, Johanna


    Several studies have shown that the mycotoxins T-2 toxin, diacetoxyscirpenol (DAS), deoxynivalenol (DON) and nivalenol (NIV) affect lymphocyte functioning. However, the molecular mechanisms underlying the immunomodulatory effects of these trichothecenes are not defined yet. In this study, the potency of the type A trichothecenes T-2 toxin and DAS, and the type B trichothecenes DON (and its metabolite de-epoxy-deoxynivalenol; DOM-1) and NIV to reduce mitochondrial activity and to induce apoptosis of Jurkat T cells (human T lymphocytes) were examined. T-2 toxin and DAS are much more cytotoxic at low concentrations than DON and NIV as shown by the AlamarBlue cytotoxicity assay. In addition, the mechanism whereby DON and NIV induced cytotoxicity is mainly via apoptosis as we observed phosphatidylserine externalization, mitochondrial release of cytochrome c, procaspase-3 degradation and Bcl-2 degradation. In contrast, type A trichothecenes reduce the mitochondrial activity at approximately 1000-fold lower concentrations than the type B trichothecenes, resulting in necrosis. These data suggest that the mechanisms resulting in cytotoxic effects are different for type A and type B trichothecenes.

  7. Subclass of individual IgA-secreting human lymphocytes. Investigation of in vivo pneumococcal polysaccharide-induced and in vitro mitogen-induced blood B cells by monolayer plaque-forming cell assays

    DEFF Research Database (Denmark)

    Heilmann, C; Barington, T; Sigsgaard, T


    The subclass of individual human IgA B cells was investigated by means of monolayer plaque-forming cell assays permitting analysis of all IgA-secreting cells as well as of cells secreting IgA anti-pneumococcal polysaccharide antibody. Center cells were examined by indirect immunofluorescence...... that these Ag have an unusually high ability to activate IgA2 B cells, or that the B cells stimulated originate from lymphatic tissues with a high frequency of IgA2 committed cells....... staining with mouse mAb against either of the two IgA subclasses as primary antibodies and FITC-conjugated rabbit anti-mouse Ig as the second antibody. Blood lymphocytes spontaneously secreting IgA (mean 399/10(6) mononuclear cells) produced mainly IgA1 (73%). A similar distribution of subclasses...

  8. Protective effect of Crataegus monogyna Jacq. ethanolic extracts in oxidant-induced DNA damage evaluated through comet assay with human peripheral lymphocytes

    Directory of Open Access Journals (Sweden)

    Joao C. M. Barreira


    The results showed significant differences within the assessed botanical parts and also among the assayed concentrations. The performed investigation might be considered as representing a step further in the evaluation of the in vivo bioactive potential of this highly promising species. Furthermore, it has established some practical bases for the evaluation of additional natural matrices with high scoring in bioactivity screening studies.


    Institute of Scientific and Technical Information of China (English)


    @@Human biomonitoring of early genetic effects requires accurate, sensitive and, if possible, easy and not too time-consuming methodologies to assess mutations. One of the most promising methodologies today is the cytokinesis block micronucleus assay, which detects both chromosome breakage and chromosome loss in once-divided

  10. Astaxanthin, a Carotenoid, Stimulates Immune Responses by Enhancing IFN-γ and IL-2 Secretion in Primary Cultured Lymphocytes in Vitro and ex Vivo. (United States)

    Lin, Kuan-Hung; Lin, Kao-Chang; Lu, Wan-Jung; Thomas, Philip-Aloysius; Jayakumar, Thanasekaran; Sheu, Joen-Rong


    Astaxanthin, a potent antioxidant carotenoid, plays a major role in modulating the immune response. In this study, we examined the immunomodulatory effects of astaxanthin on cytokine production in primary cultured lymphocytes both in vitro and ex vivo. Direct administration of astaxanthin (70-300 nM) did not produce cytotoxicity in lipopolysaccharide (LPS, 100 µg/ mL)- or concanavalin A (Con A, 10 µg/ mL)-activated lymphocytes, whereas astaxanthin alone at 300 nM induced proliferation of splenic lymphocytes (p astaxanthin, alone or with Con A, had no apparent effect on interferon (INF-γ) and interleukin (IL-2) production in primary cultured lymphocytes, it enhanced LPS-induced INF-γ production. In an ex vivo experiment, oral administration of astaxanthin (0.28, 1.4 and 7 mg/kg/day) for 14 days did not cause alterations in the body or spleen weights of mice and also was not toxic to lymphocyte cells derived from the mice. Moreover, treatment with astaxanthin significantly increased LPS-induced lymphocyte proliferation ex vivo but not Con A-stimulated lymphocyte proliferation ex vivo. Enzyme linked immunosorbent assay (ELISA) analysis revealed that administration of astaxanthin significantly enhanced INF-γ production in response to both LPS and Con A stimulation, whereas IL-2 production increased only in response to Con A stimulation. Also, astaxanthin treatment alone significantly increased IL-2 production in lymphocytes derived from mice, but did not significantly change production of INF-γ. These findings suggest that astaxanthin modulates lymphocytic immune responses in vitro, and that it partly exerts its ex vivo immunomodulatory effects by increasing INF-γ and IL-2 production without inducing cytotoxicity.

  11. Cytotoxicity and genotoxicity of biogenic silver nanoparticles (United States)

    Lima, R.; Feitosa, L. O.; Ballottin, D.; Marcato, P. D.; Tasic, L.; Durán, N.


    Biogenic silver nanoparticles with 40.3 ± 3.5 nm size and negative surface charge (- 40 mV) were prepared with Fusarium oxysporum. The cytotoxicity of 3T3 cell and human lymphocyte were studied by a TaliTM image-based cytometer and the genotoxicity through Allium cepa and comet assay. The results of BioAg-w (washed) and BioAg-nw (unwashed) biogenic silver nanoparticles showed cytotoxicity exceeding 50 μg/mL with no significant differences of response in 5 and 10 μg/mL regarding viability. Results of genotoxicity at concentrations 5.0 and 10.0 ug/mL show some response, but at concentrations 0.5 and 1.0 μg/mL the washed and unwashed silver nanoparticles did not present any effect. This in an important result since in tests with different bacteria species and strains, including resistant, MIC (minimal inhibitory concentration) had good answers at concentrations less than 1.9 μg/mL. This work concludes that biogenic silver nanoparticles may be a promising option for antimicrobial use in the range where no cyto or genotoxic effect were observed. Furthermore, human cells were found to have a greater resistance to the toxic effects of silver nanoparticles in comparison with other cells.

  12. Cytotoxicity of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)


    With large-scale production and application at large scale, carbon nanotubes (CNTs) may cause ad-verse response to the environment and human health. Thus, study on bio-effects and safety of CNTs has attracted great attention from scientists and governments worldwide. This report briefly summa-rizes the main results from the in vitro toxicity study of CNTs. The emphasis is placed on the descrip-tion of a variety of factors affecting CNTs cytotoxicity, including species of CNTs, impurities contained, lengths of CNTs, aspect ratios, chemical modification, and assaying methods of cytotoxicity. However, experimental information obtained thus far on CNTs’ cytotoxicity is lacking in comparability, and some-times there is controversy about it. In order to assess more accurately the potential risks of CNTs to human health, we suggest that care should be taken for issues such as chemical modification and quantitative characterization of CNTs in cytotoxicity assessment. More importantly, studies on physical and chemical mechanisms of CNTs’ cytotoxicity should be strengthened; assaying methods and evaluating criteria characterized by nanotoxicology should be gradually established.

  13. Cytotoxicity of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    ZHU Ying; LI WenXin


    With large-scale production and application at large scale, carbon nanotubes (CNTs) may cause ad-verse response to the environment and human health. Thus, study on bio-effects and safety of CNTs has attracted great attention from scientists and governments worldwide. This report briefly summa-rizes the main results from the in vitro toxicity study of CNTs. The emphasis is placed on the descrip-tion of a variety of factors affecting CNTs cytotoxicity, including species of CNTs, impurities contained,lengths of CNTs, aspect ratios, chemical modification, and assaying methods of cytotoxicity. However,experimental information obtained thus far on CNTs' cytotoxicity is lacking in comparability, and some-times there is controversy about it. In order to assess more accurately the potential risks of CNTs to human health, we suggest that care should be taken for issues such as chemical modification and quantitative characterization of CNTa in cytotoxicity assessment. More importantly, studies on physical and chemical mechanisms of CNTs' cytotoxicity should be strengthened; assaying methods and evaluating criteria characterized by nanotoxicology should be gradually established.

  14. Cannabinoids inhibit T-cells via cannabinoid receptor 2 in an in vitro assay for graft rejection, the mixed lymphocyte reaction. (United States)

    Robinson, Rebecca Hartzell; Meissler, Joseph J; Breslow-Deckman, Jessica M; Gaughan, John; Adler, Martin W; Eisenstein, Toby K


    Cannabinoids are known to have anti-inflammatory and immunomodulatory properties. Cannabinoid receptor 2 (CB2) is expressed mainly on leukocytes and is the receptor implicated in mediating many of the effects of cannabinoids on immune processes. This study tested the capacity of Δ(9)-tetrahydrocannabinol (Δ(9)-THC) and of two CB2-selective agonists to inhibit the murine Mixed Lymphocyte Reaction (MLR), an in vitro correlate of graft rejection following skin and organ transplantation. Both CB2-selective agonists and Δ(9)-THC significantly suppressed the MLR in a dose dependent fashion. The inhibition was via CB2, as suppression could be blocked by pretreatment with a CB2-selective antagonist, but not by a CB1 antagonist, and none of the compounds suppressed the MLR when splenocytes from CB2 deficient mice were used. The CB2 agonists were shown to act directly on T-cells, as exposure of CD3(+) cells to these compounds completely inhibited their action in a reconstituted MLR. Further, the CB2-selective agonists completely inhibited proliferation of purified T-cells activated by anti-CD3 and anti-CD28 antibodies. T-cell function was decreased by the CB2 agonists, as an ELISA of MLR culture supernatants revealed IL-2 release was significantly decreased in the cannabinoid treated cells. Together, these data support the potential of this class of compounds as useful therapies to prolong graft survival in transplant patients.

  15. Ex-vivo cytotoxic, antibacterial and DPPH free radical scavenging assay with ethanolic leaf extract of Glycosmis pentaphylla to justify its traditional use

    Directory of Open Access Journals (Sweden)

    Prawej Ansari1,2


    Full Text Available Aim: Glycosmis pentaphylla belongs to the family Rutaceae. It is a shrub and locally common in the treatment of hepatic impairment. We have designed this study to provide a scientific basis with the traditional use of leaf of G. pentaphylla in the treatment of hepatitis.Methods: The well-established DPPH free radical scavenging activity was tested for antioxidant property evaluation. On the other hand, disk diffusion and brine shrimp method was respecti-velyused to determine antibacterial and cytotoxic activity. Results and Discussion: In the evaluation of antioxidant property IC50 found 204.91+/- 2.223 and micro;g/ml, in cytotoxicity testing, it is found that the plant part shows 30.49 +/- 1.976 and micro;g/ml of LC50. The ethanolic extract of G. pentaphylla leaves also have efficiency in bacterial growth inhibition; this extract is effective against for both gram, negative and positive. The zone of inhibition at 500 and micro;g/ml dose in E. coli and C. albican culture was 18 mm and 15 mm, respectively. In thin layer chromatography analysis, we found presence of couple of non-polar and polar component, presence of three non-chromatophoric component are also evident.Conclusion: Appropriate isolation and identification of mechanism is suggested in further study. [Biomed Res Ther 2015; 2(7.000: 324-332

  16. Cytotoxicity and genotoxicity of a monazite component: lanthanum effects on the viability and induction of breaks in the DNA of human lymphocytes; Citotoxicidade e genotoxicidade de um componente da monazita: efeitos do lantanio na viabilidade e inducao de quebras no DNA de linfocitos humanos

    Energy Technology Data Exchange (ETDEWEB)

    Paiva, Amanda Valle de Almeida


    The Monazite is a mineral extracted from open mines. It is constituted by lanthanum element aggregated with cerium, yttrium and thorium [(Ce, La, Y, Th)PO{sub 4}]. Lanthanum (La) is a rare-earth metal with applications in agriculture, industry and medicine. Since lanthanides and their compounds show a broad spectrum of applications there is an increased risk of incorporation in human. Inhalation of aerosols containing La is the main route of incorporation in workers exposed to several chemical forms of La. Herein, we examined the effect of lanthanum nitrate - La(NO{sub 3}){sub 3} in human lymphocytes. JURKAT cells and human peripheral lymphocytes (HPL) were used to evaluate the effect of La(NO{sub 3}){sub 3} on viability (apoptosis or necrosis) and DNA strand breaks induction or/and alkali-labile sites (ALS). We demonstrate that La has a cytotoxic and genotoxic effect on both cell lines. The results indicate that necrosis is the pathway by which La(NO{sub 3}){sub 3} induces cytotoxicity. The vitamin E is able to diminish DNA strand breaks induced by La(NO{sub 3}){sub 3} suggesting that reactive oxygen species (ROS) may be involved in the genotoxic process. (author)

  17. The anti-tumor activity of dendritic cell/cytotoxic T lymphocyte induced by cholangiocarcinoma-derived exosome and its ultrafiltered lysate%基于exosome裂解超滤液的树突状细胞/细胞毒性T淋巴细胞诱导及其抗胆管癌研究

    Institute of Scientific and Technical Information of China (English)

    陈炯煌; 丁国平; 陈文超; 曹利平


    Objective To observe the impact of cholangiocarcinoma-derived exosome and ultrafiltered exosome lysate on the anti-tumor activity of dendritic celL/cytotoxic T lymphocyte (DC/CTL) cells and discuss the mechanism involved.Methods Exosomes derived from RBE cells (human cholangiocarcinoma line) were collected by ultracentrifugation,ow-osmotic splitting followed by ultrafiltration was performed to remove exosomal microRNAs and purify the ultrafiltered exosome lysate.ImDCs (immature dendritic cells) were induced from peripheral blood and were co-cultured with CTL(cytotoxic lymphocyte),which were impulsed by exosome and ultrafiltered exosome lysate,respectively.The concentrations of tumor necrosis factor (TNF)-αt and perforin in culture medium supernatant were examined by enzyme linked immunosorbent assay (ELISA).Cell counting kit-8 (CCK-8) was used to evaluate the cytotoxic activity of DC/CTL to RBE cells.Results The concentrations of TNF-αand perforin in E-DC/CTL group were 138.61 ng/L and 2.41 μg/L respectively,lower than those of DC/CTL (194.08 ng/L and 3.39 μg/L) and EL-DC/CTL group (210.87 ng/L and 3.79 μg/L).The killing rate of E-DC/CTL was 33.35%,lower than that of DC/CTL (47.35%) and EL-DC/CTL (66.23%) significantly.The killing rate of EL-DC/CTL was significantly higher than that of DC/CTL (P < 0.01).Conclusion RBE cell-derived exosome inhibits the anti-tumor activity of DC/CTL by down-regulating TNF-α and perforin,exosomal miRNA may play important roles in the immune escape of cholangiocarcinoma.We built a new model based on ultrafiltered exosome lysate derived from cholangiocarcinoma to enhance the anti-tumor activity of DC/CTL.%目的 观察人胆管癌细胞来源的exosome及exosome裂解超滤液(UEL)对树突状细胞/细胞毒性T淋巴细胞诱导(DC/CTL)混合细胞抗肿瘤活性的影响及机制.方法 采用超速离心法提取人胆管癌细胞(RBE细胞)释放的exosome,低渗法裂解exosome,超

  18. A real time Metridia luciferase based non-invasive reporter assay of mammalian cell viability and cytotoxicity via the β-actin promoter and enhancer. (United States)

    Lupold, Shawn E; Johnson, Tamara; Chowdhury, Wasim H; Rodriguez, Ronald


    Secreted reporter molecules offer a means to evaluate biological processes in real time without the need to sacrifice samples at pre-determined endpoints. Here we have adapted the secreted bioluminescent reporter gene, Metridia luciferase, for use in a real-time viability assay for mammalian cells. The coding region of the marine copepod gene has been codon optimized for expression in human cells (hMLuc) and placed under the control of the human β-actin promoter and enhancer. Metridia luciferase activity of stably transfected cell models corresponded linearly with cell number over a 4-log dynamic range, detecting as few as 40 cells. When compared to standard endpoint viability assays, which measure the mitochondrial dehydrogenase reduction of tetrazolium salts, the hMLuc viability assay had a broader linear range of detection, was applicable to large tissue culture vessels, and allowed the same sample to be repeatedly measured over several days. Additional studies confirmed that MLuc activity was inhibited by serum, but demonstrated that assay activity remained linear and was measurable in the serum of mice bearing subcutaneous hMLuc-expressing tumors. In summary, these comparative studies demonstrate the value of humanized Metridia luciferase as an inexpensive and non-invasive method for analyzing viable cell number, growth, tumor volume, and therapeutic response in real time.

  19. A real time Metridia luciferase based non-invasive reporter assay of mammalian cell viability and cytotoxicity via the β-actin promoter and enhancer.

    Directory of Open Access Journals (Sweden)

    Shawn E Lupold

    Full Text Available Secreted reporter molecules offer a means to evaluate biological processes in real time without the need to sacrifice samples at pre-determined endpoints. Here we have adapted the secreted bioluminescent reporter gene, Metridia luciferase, for use in a real-time viability assay for mammalian cells. The coding region of the marine copepod gene has been codon optimized for expression in human cells (hMLuc and placed under the control of the human β-actin promoter and enhancer. Metridia luciferase activity of stably transfected cell models corresponded linearly with cell number over a 4-log dynamic range, detecting as few as 40 cells. When compared to standard endpoint viability assays, which measure the mitochondrial dehydrogenase reduction of tetrazolium salts, the hMLuc viability assay had a broader linear range of detection, was applicable to large tissue culture vessels, and allowed the same sample to be repeatedly measured over several days. Additional studies confirmed that MLuc activity was inhibited by serum, but demonstrated that assay activity remained linear and was measurable in the serum of mice bearing subcutaneous hMLuc-expressing tumors. In summary, these comparative studies demonstrate the value of humanized Metridia luciferase as an inexpensive and non-invasive method for analyzing viable cell number, growth, tumor volume, and therapeutic response in real time.

  20. Comparison of Simplexa universal direct PCR with cytotoxicity assay for diagnosis of Clostridium difficile infection: performance, cost, and correlation with disease. (United States)

    Landry, Marie L; Ferguson, David; Topal, Jeffrey


    Simplexa Clostridium difficile universal direct PCR, a real-time PCR assay for the detection of the C. difficile toxin B (tcdB) gene using the 3M integrated cycler, was compared with a two-step algorithm which includes the C. Diff Chek-60 glutamate dehydrogenase (GDH) antigen assay followed by cytotoxin neutralization. Three hundred forty-two liquid or semisolid stools submitted for diagnostic C. difficile testing, 171 GDH antigen positive and 171 GDH antigen negative, were selected for the study. All samples were tested by the C. Diff Chek-60 GDH antigen assay, cytotoxin neutralization, and Simplexa direct PCR. Of 171 GDH-positive samples, 4 were excluded (from patients on therapy or from whom duplicate samples were obtained) and 88 were determined to be true positives for toxigenic C. difficile. Of the 88, 67 (76.1%) were positive by the two-step method and 86 (97.7%) were positive by PCR. Seventy-nine were positive by the GDH antigen assay only. Of 171 GDH antigen-negative samples, none were positive by PCR. One antigen-negative sample positive by the cytotoxin assay only was deemed a false positive based on chart review. Simplexa C. difficile universal direct PCR was significantly more sensitive for detecting toxigenic C. difficile bacteria than cytotoxin neutralization (P = 0.0002). However, most PCR-positive/cytotoxin-negative patients did not have clear C. difficile disease. The estimated cost avoidance provided by a more rapid molecular diagnosis was outweighed by the cost of isolating and treating PCR-positive/cytotoxin-negative patients. The costs, clinical consequences, and impact on nosocomial transmission of treating and/or isolating patients positive for toxigenic C. difficile by PCR but negative for in vivo toxin production merit further study.

  1. Mercuric dichloride induces DNA damage in human salivary gland tissue cells and lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Katharina; Kroemer, Susanne [University of Regensburg, Regensburg (Germany); Sassen, Andrea [University of Regensburg, Department of Pathology, Regensburg (Germany); Staudenmaier, Rainer [Technical University of Munich, Department of Otorhinolaryngology, Head and Neck Surgery, Munich (Germany); Reichl, Franz-Xaver [University of Munich, Institute of Pharmacology and Toxicology, Munich (Germany); Harreus, Ulrich [University of Munich, Department of Otorhinolaryngology, Head and Neck Surgery, Munich (Germany); Hagen, Rudolf; Kleinsasser, Norbert [University of Wuerzburg, Department of Otorhinolaryngology, Head and Neck Surgery, Wuerzburg (Germany)


    Amalgam is still one of the most frequently used dental filling materials. However, the possible adverse effects especially that of the mercuric component have led to continued controversy. Considering that mercury may be released from amalgam fillings into the oral cavity and also reach the circulating blood after absorption and resorption, it eventually may contribute to tumorigenesis in a variety of target cells. The present investigation focuses on genotoxic effects below a cytotoxic dose level of mercuric dichloride (HgCl{sub 2}) in human samples of salivary glands and lymphocytes to elucidate a possible role in tumor initiation. DNA migration due to single strand breaks, alkali labile sites and incomplete excision repair was quantified with the aid of the single cell microgel electrophoresis (Comet) assay. The concepts of Olive Tail Moment, percentage of DNA in the Tail and Tail Length were used as measures of DNA damage. To control for cytotoxic effects, the trypan blue exclusion test was applied. Human samples of the parotid salivary gland and lymphocytes of ten donors were exposed to HgCl{sub 2} concentrations from 1 to 50 {mu}M. N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and dimethyl sulfoxide (DMSO) served as controls. Increasing dose-dependent DNA migration could be demonstrated after exposure to HgCl{sub 2} in cells of the salivary glands and lymphocytes. In both cell types a significant increase in DNA migration could be shown starting from HgCl{sub 2} concentrations of 5 {mu}M in comparison to the negative control. The viability of the cell systems was not affected except at the highest concentration (50 {mu}M) tested. These data indicate genotoxic effects of mercuric dichloride in human salivary glands and lymphocytes at concentrations not leading to cytotoxic effects or cell death. Consequently, a contributory role in oral salivary gland tumor initiation warrants further investigation. (orig.)

  2. Identification of the murine H-2D(b) and human HLA-A*0201 MHC class I-restricted HPV6 E7-specific cytotoxic T lymphocyte epitopes. (United States)

    Peng, Shiwen; Mattox, Austin; Best, Simon R; Barbu, Anca M; Burns, James A; Akpeng, Belinda; Jeang, Jessica; Yang, Benjamin; Ishida, Eiichi; Hung, Chien-Fu; Wu, Tzyy-Choou; Pai, Sara I


    Recurrent respiratory papillomatosis is caused by human papillomavirus (HPV) infection, most commonly types 6 (HPV-6) and 11 (HPV-11). Due to failed host immune responses, HPV is unable to be cleared from the host, resulting in recurrent growth of HPV-related lesions that can obstruct the lumen of the airway within the upper aerodigestive tract. In our murine model, the HPV-6b and HPV-11 E7 antigens are not innately immunogenic. In order to enhance the host immune responses against the HPV E7 antigen, we linked calreticulin (CRT) to HPV-6b E7 and found that vaccinating C57BL/6 mice with the HPV-6b CRT/E7 DNA vaccine is able to induce a CD8+ T cell response that recognizes an H-2D(b)-restricted E7aa21-29 epitope. Additionally, vaccination of HLA-A*0201 transgenic mice with HPV-6b CRT/E7 DNA generated a CD8+ T cell response against the E7aa82-90 epitope that was not observed in the wild-type C57BL/6 mice, indicating this T cell response is restricted to HLA-A*0201. In vivo cytotoxic T cell killing assays demonstrated that the vaccine-induced CD8+ T cells are able to efficiently kill target cells. Interestingly, the H-2D(b)-restricted E7aa21-29 sequence and the HLA-A*0201-restricted E7aa82-90 sequence are conserved between HPV-6b and HPV-11 and may represent shared immunogenic epitopes. The identification of the HPV-6b/HPV-11 CD8+ T cell epitopes facilitates the evaluation of various immunomodulatory strategies in preclinical models. More importantly, the identified HLA-A*0201-restricted T cell epitope may serve as a peptide vaccination strategy, as well as facilitate the monitoring of vaccine-induced HPV-specific immunologic responses in future human clinical trials.

  3. Screening and identification of HLA-A0201 restricted cytotoxic T lymphocyte epitopes from hepatitis B virus E antigen in vitro%HBeAg人类白细胞抗原-A0201限制性细胞毒性T淋巴细胞表位的筛选与鉴定

    Institute of Scientific and Technical Information of China (English)

    陈娟; 吴金明; 张欢; 黄兰


    Objective To identify HLA-A0201 restricted cytotoxic T lymphocyte (CTL) epitopes derived from the hepatitis B virus e (HBe) antigen,for future use in a specific immunotherapy based on the identified epitope(s).Methods HBe gene sequences from the hepatitis B virus serotypes with the highest frequencies in China were analyzed by bioinformatic web-based interfaces for quantitative motif prediction,extended motif prediction,and peptide super-motif prediction.Four candidate peptides were identified:HBe1,HBe2,HBe3,and HBe4.The affinities of each were tested in vitro with T2 cells,which lack the transporter-associated with antigen transport (TAP) protein but express low levels of the MHC class Ⅰ surface molecule,and measured by the T2 binding assay and DC50 assay.Flow cytometry was used to detect the fluorescence index of control and experimental groups.Results The peptides HBe1 (LLWFHISCL),HBe2 (YLVSFGVWI),HBe3 (CLTFGRETV),and HBe4 (DLLDTASAL) were identified and tested as candidate targets.HBe2 and HBe3 showed higher HLA-A0201 affinity.HBe1,HBe2,and HBe3 showed better binding stability.Conclusion Two peptides based on HBe antigen,YLVSFGVWI and CLTFGRETV,possess both sufficient binding affinity and stability and may represent useful HLA-A0201-restricted CTL epitopes.Further study is needed to determine the immunogenic properties of these two peptides in vivo.%目的 通过筛选和鉴定HBeAg来源的人类白细胞抗原(HLA)-A0201限制性细胞毒性T淋巴细胞(CTL)表位,为HBeAg表位的特异性治疗性疫苗的开发奠定基础. 方法 选择中国人群最常见的B基因型中的adw血清型的HBV e基因序列,通过网络在线表位筛选服务,分析得到分数比较高,而且是一样的表位,然后采用量化基序方案、延展基序方案以及超基序方案等通用表位筛选原则进行进一步的筛选,得到4条较为理想的九肽(HBe1,HBe2,HBe3,HBe4)作为候选表位.随后借助于流式细胞技术,通过T2细胞实验分析各

  4. Peripheral lymphocyte subpopulations in recurrent aphthous ulceration

    DEFF Research Database (Denmark)

    Pedersen, A; Klausen, B; Hougen, H P


    Peripheral lymphocyte subsets--T-helper (CD4+), T-suppressor/cytotoxic (CD8+), and naive/virgin T cells/natural killer cells (CD45RA)--were studied quantitatively in 30 patients with recurrent aphthous ulceration (RAU) and 29 sex- and age-matched RAU-free control donors. The CD4+ percentage was s...

  5. Development of an Immunoperoxidase Monolayer Assay for the Detection of Antibodies against Peste des Petits Ruminants Virus Based on BHK-21 Cell Line Stably Expressing the Goat Signaling Lymphocyte Activation Molecule (United States)

    Chen, Weiye; Li, Cuicui; Xie, Meimei; Bu, Zhigao


    From 2013 to 2015, peste des petits ruminants (PPR) broke out in more than half of the provinces of China; thus, the application and development of diagnostic methods are very important for the control of PPR. Here, an immunoperoxidase monolayer assay (IPMA) was developed to detect antibodies against PPR. However, during IPMA development, we found that Vero cells were not the appropriate choice because staining results were not easily observed. Therefore, we first established a baby hamster kidney-goat signaling lymphocyte activation molecule (BHK-SLAM) cell line that could stably express goat SLAM for at least 20 generations. Compared with Vero cells, the PPR-mediated cytopathic effect occurred earlier in BHK-SLAM cells, and large syncytia appeared after virus infection. Based on this cell line and recombinant PPR virus expressing the green fluorescent protein (GFP) (rPPRV-GFP), an IPMA for PPR diagnosis was developed. One hundred and ninety-eight PPR serum samples from goats or sheep were tested by the IPMA and virus neutralization test (VNT). Compared with the VNT, the sensitivity and specificity of the IPMA were 91% and 100%, respectively, and the coincidence rate of the two methods was 95.5%. The IPMA assay could be completed in 4 h, compared with more than 6 d for the VNT using rPPRV-GFP, and it is easily performed, as the staining results can be observed under a microscope. Additionally, unlike the VNT, the IPMA does not require antigen purification, which will reduce its cost. In conclusion, the established IPMA will be an alternative method that replaces the VNT for detecting antibodies against PPRV in the field. PMID:27768770

  6. Leukoreduction system chambers are an efficient, valid, and economic source of functional monocyte-derived dendritic cells and lymphocytes. (United States)

    Pfeiffer, Isabell A; Zinser, Elisabeth; Strasser, Erwin; Stein, Marcello F; Dörrie, Jan; Schaft, Niels; Steinkasserer, Alexander; Knippertz, Ilka


    The demand for human monocyte-derived dendritic cells (moDCs), as well as for primary human B and T lymphocytes for immunological research purposes has been increased in recent years. Classically, these monocytes are isolated from blood, leukapheresis products or buffy coats of healthy donors by plastic adherence of peripheral blood mononuclear cells (PBMCs), followed by stimulation with granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4, while lymphocytes are usually isolated from the non-adherent fraction (NAF) by magnetic cell sorting. However, donor-blood is a limited resource and not every blood bank offers leukapheresis products or buffy coats for laboratory use. Additionally, a leukapheresis is very expensive and also the generation/isolation of cells is time- and cost-intensive. To overcome some of these obstacles, we evaluated if low-cost leukoreduction system chambers (LRSCs), which arise after routine donor plateletpheresis procedures, and are usually discarded, would be an alternative and appropriate source of PBMCs to generate moDCs and to isolate lymphocytes. By analyzing the number and phenotype of immature and mature dendritic cells (DCs), as well as of B and T lymphocytes derived from LRSCs, we found all cells to be of high quantity and quality. Further investigations on DCs comprising transwell migration assays, allogeneic mixed lymphocyte reactions (MLR), cytokine secretion assays, and cytotoxic T cell induction assays revealed high migratory, as well as stimulatory capacity of these cells. In addition, DCs and T cells were efficiently electroporated with mRNA and showed characteristic cytokine production after co-culture, demonstrating LRSCs as an efficient, valid, and economic source for generation of moDCs and lymphocytes for research purposes.

  7. 19. The HUman Micro Nucleus project. International Date Base Comparison for results with the cytokinesis-block micronucleus assay in human lymphocytes. Ⅰ. Effect of laboratory protocol, scoring criteria, and host factors on the frequency of micronuclei

    Institute of Scientific and Technical Information of China (English)


    The first results of an analysis of pooled data from laboratories using the cytokinesis-block micronucleus assay in human lymphocytes and participating in the HUMN (HUman MicroNucleus project) international collaborative study are presented. The effects of laboratory protocol, scoring criteria, and host factors on baseline micronucleus(MN) frequency are evaluated, and a reference range of “normal” values against which future studies may be compared is provided. Primary data from historical records were submitted by 25 laboratories distributed in 16 countries. This resulted in a database of nearly 7000 subjects. Potentially significant differences were present in the methods used by participating laboratories, such as in the type of culture medium, the concentration of Cytochalasin-B, the percentage of fetal calf serum, and in the culture method. Differences in criteria for scoring MN were also evident. The overall median MN frequency in non-exposed(i.e., normal) subjects was 6.5‰ and the interquartile range was between 3‰ and 12‰. An increase in MN frequency with age was evident in all but two laboratories. The effect of gender, although not so evident in all databases, was also present, with females having a 19% higher level of MN (95% C.I.:14-24%). Statistical analyses were performed using random-effects models for correlated data. Our best model, which included exposure to genotoxic factors, host factors, methods, and scoring criteria, explained 75% of the total variance, with the largest contribution attributable to laboratory methods.

  8. Clonal Expansion and Cytotoxicity of TCRVβ Subfamily T Cells Induced by CML and K562 Cells

    Institute of Scientific and Technical Information of China (English)

    YupingZHang; YangqiuLi; ShaohuaChen; LijianYang; GengxinLuo; XueliZhang


    OBJECTIVE To investigate the anti-leukemia effect, the distribution and clonal expansion of TCRVβ subfamily T cells in T cells from cord blood and adult peripheral blood induced by CML cells and K562 cells in vitro. METHODS Peripheral blood T cells from one adult donor and 3 cases of cord blood were stimulated with CML cells and K562 cells and further amplified by a suspended T cell-bulk culture,in order to induce CML specific cytotoxic T lymphocytes. The induced T cells were further analyzed for the specific cytotoxicity in CML by LDH assay, the phenotype identification by indirect immunofiuorescence technique and the distribution and clonal expansion of TCRVβ subfamily by using reverse transcriptase-polymerase chain reaction (RT-PCR) and genescan analysis, respectively. RESULTS Oligoclonal and oligoclonal tendency T cells with higher specific cytotoxicity from cord blood and adult peripheral blood could be induced by stimulation with CML cells and K562 cells. CONCLUSIONS Specific cytotoxic T cells for an anti-CML effect could be induced by CML cells and K562 cells .The induced T cells which have the characteristic of specific cytotoxicity against CML cells may come from the clonal expansion of TCRVβ subfamily T cells.

  9. Environmental and human risk assessment of landfill leachate: An integrated approach with the use of cytotoxic and genotoxic stress indices in mussel and human cells

    Energy Technology Data Exchange (ETDEWEB)

    Toufexi, Eirini; Tsarpali, Vasiliki [Section of Animal Biology, Department of Biology, School of Natural Sciences, University of Patras, GR 26500 Patras (Greece); Efthimiou, Ioanna; Vidali, Maria-Sophia; Vlastos, Dimitris [Department of Environmental and Natural Resources Management, University of Patras, 2 Seferi Str., GR 30100 Agrinio (Greece); Dailianis, Stefanos, E-mail: [Section of Animal Biology, Department of Biology, School of Natural Sciences, University of Patras, GR 26500 Patras (Greece)


    Highlights: • Landfill leachate poses a threat for aquatic biota and humans. • Leachate induces cytotoxic and oxidative effects on mussel hemocytes. • Increased levels of DNA damage were observed both in vivo and in vitro in hemocytes. • Leachate low doses enhance MN formation in human lymphocyte cultures. • Potential leachate aneugenic activity was detected in human lymphocytes. -- Abstract: The present study investigates leachate hazardous effects on marine biota and human cells, with the use of a battery of assays, both under in vivo and in vitro conditions. According to the results, mussels exposed for 4 days to 0.01 and 0.1% (v/v) of leachate showed increased levels of DNA damage and micronuclei (MN) frequencies in their hemocytes. Similarly, enhanced levels of DNA damage were also observed in hemocytes treated in vitro with relevant concentrations of leachate, followed by a significant enhancement of both superoxide anions (·O{sub 2}{sup −}) and lipid peroxidation products (malondialdehyde/MDA). On the other hand, human lymphocyte cultures treated with such a low concentrations of leachate (0.1, 0.2 and 1%, v/v), showed increased frequencies of MN formation and large MN size ratio, as well as decreased cell proliferation, as indicated by the use of the cytokinesis block micronucleus (CBMN) assay and Cytokinesis Block Proliferation Index (CBPI) respectively. These findings showed the clear-cut genotoxic and cytotoxic effects of leachate on both cellular types, as well as its potential aneugenic activity in human lymphocytes.

  10. Two zinc-aminoclays' in-vitro cytotoxicity assessment in HeLa cells and in-vivo embryotoxicity assay in zebrafish. (United States)

    Chun, Hang-Suk; Park, Duckshin; Eun Lim, Song; Jeong, Kwang-Hun; Park, Ji-Seon; Park, Han-Jin; Kang, Shinyoung; Kang, Kyoung Suk; Park, Hyun Gyu; An, Ha-Rim; Huh, Yun Suk; Lee, Young-Chul


    Two zinc-aminoclays [ZnACs] with functionalized primary amines [(-CH2)3NH2] were prepared by a simple sol-gel reaction using cationic metal precursors of ZnCl2 and Zn(NO3)2 with 3-aminopropyl triethoxysilane [APTES] under ambient conditions. Due to the facile interaction of heavy metals with primary amine sites and Zn-related intrinsic antimicrobial activity, toxicity assays of ZnACs nanoparticles (NPs) prior to their environmental and human-health applications are essential. However, such reports remain rare. Thus, in the present study, a cell viability assay of in-vitro HeLa cells comparing ZnCl2, Zn(NO3)2 salts, and ZnO (~50nm average diameter) NPs was performed. Interestingly, compared with the ZnCl2, and Zn(NO3)2 salts, and ZnO NPs (18.73/18.12/51.49µg/mL and 18.12/15.19/46.10µg/mL of IC50 values for 24 and 48h), the two ZnACs NPs exhibited the highest toxicity (IC50 values of 21.18/18.36µg/mL and 18.37/17.09µg/mL for 24 and 48h, respectively), whose concentrations were calculated on Zn elemental composition. This might be due to the enhanced bioavailability and uptake into cells of ZnAC NPs themselves and their positively charged hydrophilicity by reactive oxygen species (ROS) generation, particularly as ZnACs exist in cationic NP's form, not in released Zn(2+) ionic form (i.e., dissolved nanometal). However, in an in-vivo embryotoxicity assay in zebrafish, ZnACs and ZnO NPs showed toxic effects at 50-100µg/mL (corresponding to 37.88-75.76 of Zn wt% µg/mL). The hatching rate (%) of zebrafish was lowest for the ZnO NPs, particularly where ZnAC-[(NO3)2] is slightly more toxic than ZnAC-[Cl2]. These results are all very pertinent to the issue of ZnACs' potential applications in the environmental and biomedical fields.

  11. Cytotoxic T-lymphocyte clones, established by stimulation with the HLA-A2 binding p5365-73 wild type peptide loaded on dendritic cells In vitro, specifically recognize and lyse HLA-A2 tumour cells overexpressing the p53 protein

    DEFF Research Database (Denmark)

    Barfoed, Annette Malene; Petersen, T R; Kirkin, A F;


    to carry identical T-cell receptors. The CTL clone, 2D9, was shown to specifically lyse the HLA-A*0201+ squamous carcinoma cell line SCC9 and the breast cancer cell line MDA-MB-468. Our data demonstrate that human peripheral blood lymphocytes from normal healthy individuals comprise T cells capable...... of recognizing p53 derived wild type (self) peptides. Furthermore, the capacity of R9V specific T cell clones to exert HLA restricted cytotoxicity, argues that the R9V peptide is naturally presented on certain cancer cells. This supports the view that p53 derived wild type peptides might serve as candidate...... target antigens for the immunotherapeutic treatment of cancer....

  12. A novel metabolite from aspergillus ochraceus JGI 25 showing cytotoxicity to hela cells

    Directory of Open Access Journals (Sweden)

    Varalakshmi K Nadumane


    Full Text Available This study aims at the isolation of filamentous fungi, extraction of metabolites, and evaluation of the cytotoxic properties on HeLa cells and normal human lymphocytes. We isolated fungi from the soil by serial dilution method. One of the isolates was chosen and identified as Aspergillus ochraceus Wilhelm (Trichocomaceae by standard techniques. The metabolites were extracted using methanol. Different concentrations of the extract were evaluated for their potential anticancer activity on HeLa cells by 3-(4,5-dimethylthiazol-2yl-2,5-diphenyl tetrazolium bromide assay and the safety of the extract was checked on normal human lymphocytes. The extract was purified by chromatographic techniques like thin-layer chromatography and high-performance liquid chromatography, and subjected to mass spectrometric analysis. The extract showed significant cytotoxic potential on HeLa cells at low concentrations with a half maximal inhibitory concentration value of <50 ΅g/ml. The extract gave 10 fractions by thin layer chromatography, and fraction B had higher toxicity than the rest. This fraction gave a single peak by high-performance liquid chromatography and had a mass-to-charge ratio of 905.65, which did not match any of the earlier known fungal metabolites or metabolites from other strains of A. ochraceus. The metabolite from A. ochraceus is alkaloid in nature, cytotoxic to HeLa cells, and appears to be a novel with anticancer potentials, which could be explored further for characterization of the active component.

  13. Evaluation of the cytotoxic and genotoxic potential of lecithin/chitosan nanoparticles (United States)

    Taner, Gökçe; Yeşilöz, Recep; Özkan Vardar, Deniz; Şenyiğit, Taner; Özer, Özgen; Degen, Gisela H.; Başaran, Nurşen


    Nanoparticles-based drug targeting delivery systems have been introduced in the treatment for various diseases because of their effective properties, although there have been conflicting results on the toxicity of nanoparticles. In the present study, the aim was to evaluate the cytotoxicity and the genotoxicity of different concentrations of lecithin/chitosan nanoparticles with and without clobetasol-17-propionate (CP) by neutral red uptake (NRU) cytotoxicity assay and single cell gel electrophoresis (Comet) and cytokinesis-blocked micronucleus assays. The IC50 values of lecithin/chitosan nanoparticles with/without CP were found as 1.9 and 1.8 %, respectively, in the NRU cytotoxicity test. High concentrations of lecithin/chitosan nanoparticles induced DNA damage in human lymphocytes as evaluated by comet assay. The micronucleus frequency was increased by the lecithin/chitosan treatment in a dose-dependent manner. Also at the two highest concentrations, a significant increase in micronucleus formation was observed. Lecithin/chitosan nanoparticles with CP did not increase the frequency of micronucleus and also did not induce additional DNA damage when compared with lecithin/chitosan nanoparticles without CP; therefore, CP itself has not found to be genotoxic at the studied concentration.

  14. 短短芽孢杆菌降解芘的细胞毒性分析%Cytotoxicity Assay of Pyrene Biodegradation byBrevibacillus brevis

    Institute of Scientific and Technical Information of China (English)

    廖丽萍; 尹华; 刘芷辰; 叶锦韶; 彭辉; 刘则华


    近年来国内外对芘微生物降解过程中的菌种选育、降解性能和降解产物分析等相关报道较多,但针对芘降解菌与芘的分子作用机制研究却不多见。为了探明降解菌短短芽孢杆菌(Brevibacillus brevis)与芘的分子作用机制,考察了B. brevis对质量浓度为1.0 mg·L-1的芘的生物降解,分析了在无机盐培养基中B. brevis与芘作用过程中,其细胞凋亡规律及膜电位的变化,以期从细胞毒性的角度揭示PAHs的微生物降解机理。实验结果显示芘的降解率随着处理时间的增加而呈上升趋势, B. brevis对芘的降解率在168 h达到56.5%。在芘的降解过程中,细胞出现显著的凋亡现象,细胞总凋亡率与细胞早期凋亡率均在48 h时达到峰值,之后均随时间的延长而下降,168 h时细胞早期凋亡率与总凋亡率均小于0.5%,菌体依然对芘具有降解能力。随着细胞凋亡的发生,细胞膜电位下降,即细胞膜电位发生去极化现象,说明细胞外的芘与 K+共转运进入细胞内,从而有助于菌体对芘的吸收与降解。%Although there have been many reports on the isolation of pyrene degrading stains, pyrene degradation characteristics and its catabolites, the information regarding molecular mechanism between degrading bacteria and pyrene is limited thus far. To explore the molecular mechanism between degrading bacteriumBrevibacillus brevis and pyrene, the biodegradation of pyrene (1.0 mg·L-1) byB. brevis, as well as the cell apoptosis and changes of membrane potential ofB. brevis under pyrene exposure in mineral salt medium (MSM) was conducted to reveal the mechanism of pyrene biodegradation from the perspective of cytotoxicity. The experimental results showed that pyrene degradation efficiency increased with time. And the biodegradation efficiency of pyrene by B. brevis reached 56.5% after 168 h. In the degradation process, pyrene significantly induced the cell

  15. Genotoxicity and cytotoxicity assay of water sampled from the underground nuclear explosion site in the north of the Perm region (Russia)

    Energy Technology Data Exchange (ETDEWEB)

    Evseeva, Tatiana I. [Institute of Biology, Komi Scientific Center, Ural Division RAS, 167982, Syktyvkar, Kommunisticheskaya 28 (Russian Federation); Geras' kin, Stanislav A. [Russian Institute of Agricultural Radiology and Agroecology RAAS, 249020 Obninsk, Kaluga region (Russian Federation)]. E-mail:; Shuktomova, Ida I. [Institute of Biology, Komi Scientific Center, Ural Division RAS, 167982, Syktyvkar, Kommunisticheskaya 28 (Russian Federation); Taskaev, Anatoliy I. [Institute of Biology, Komi Scientific Center, Ural Division RAS, 167982, Syktyvkar, Kommunisticheskaya 28 (Russian Federation)


    The results of our study revealed a local biologically relevant surface water contamination in the radionuclide anomaly in the north of Russia (Perm region) by means of Allium schoenoprasum L. anaphase-telophase chromosome aberration assay. This radionuclide anomaly was formed in 1971 as a result of an underground nuclear explosion with soil excavation. Specific activities of main dose-forming radionuclides in all examined reservoirs are below intervention levels officially adopted in Russia for drinking water. We found that {sup 90}Sr significantly contributes to induction of cytogenetic disturbances. Our previous data and the data described here suggest that metal and radionuclide combined exposure (with the dose below permissible exposure limits for human) may cause substantial biological effects. These effects are in part due to synergic response. The findings described here indicated that development of a new concept of radiation protection for humans and biota should be based on the clear understanding of biological effects of low doses of radiation in chronic exposure to multi-pollutant mixtures.

  16. Caspase-3-dependent Cell Death in B lymphocyte Caused by Pseudomonas aeruginosa Pyocyanin

    Directory of Open Access Journals (Sweden)

    Heni Susilowati


    Full Text Available Objective: The aim of this study was to investigate cellular responses of B lymphocyte to the exposure of pyocyanin and the role of caspase-3 in its molecular mechanism. Methods: B lymphocytes (Raji cells were cultured overnight prior to the experiments. Cell culture in five replications were then exposed to various concentrations of pyocyanin and incubated for 24 h in antibiotics-free medium. MTT assay was performed to analyze the cytotoxicity effect of pyocyanin. In separated experiments, the cells were cultured with pyocyanin and addressed for cell morphological analysis using phase contrast microscope. To study the mechanism involved in pyocyanin-induced cellular damage, immunocytochemical analysis was run for the identification of active caspase-3 protein expression. Results: The results of this study showed that cell viability was decreased in pcyocyanin-treated groups. Statistical analysis using ANOVA (p < 0.05 demonstrated significant different between groups with significant value of 0.000. Pyocyanin induced cell death on B lymphocyte in dose-dependent manner. Nuclear fragmentation was observed in pyocyanin-induced cell death; furthermore, caspase-3 was expressed clearly in cell cytoplasm after 24 h incubation. Conclusion: It is concluded that pyocyanin is capable of inducing cell death on B lymphocyte. Caspase-3 may play important role in the molecular mechanism of pyocyanin-induced cell death.DOI: 10.14693/jdi.v22i2.403

  17. Observation of T lymphocyte subsets in the liver of patients with advanced schistosomiasis and advanced schistosomiasis accompanied with hepatitis B. (United States)

    Zhang, S; Li, Z; Cai, S; Zeng, L


    T lymphocyte subsets in the liver were detected by Avidin-Biotin Complex (ABC) assay in 22 patients with advanced schistosomiasis (AS) and 5 cases of AS accompanied with hepatitis B. T lymphocytes in the liver of AS patients were distributed in the peripheral layer of egg granuloma or the area near eggs in non-granuloma. No infiltrative T lymphocytes were observed in area with extensive fibrosis. There was infiltration of many T cells in the portal tract, piecemeal and focal necrosis area as well as in hepatic sinus in AS patients accompanied with hepatitis B. CD8+ T cells (suppressor/cytotoxic T cells, Ts/Tc) in the liver were predominant in the two groups. In AS patients, marked hepatic fibrosis, a small number of T cell infiltration and slight hepatocellular degeneration and necrosis were observed. However, obvious hepatocellular degeneration and necrosis were seen in AS patients accompanied with hepatitis B, and 3 cases of them developed active liver cirrhosis. The results indicated immune response was weak in the liver in AS patients and Ts cells might be predominant in the subset of CD8+ T lymphocytes. Cellular immune response was relatively strong in AS patients accompanied with hepatitis B and the infiltrative CD8+ T lymphocytes might be mainly Tc cells.

  18. Comparison of complement-dependent cytotoxicity and indirect immunofluorescence for enumeration of T-cell subpopulations in human peripheral blood. (United States)

    Gratama, J W; Schuurman, R K; Van Leeuwen, A; Jansen, J; Oljans, P; Tanke, H J; Van Rood, J J


    The monitoring of T-lymphocyte subsets of recipients of organ grafts enables studies on immune reconstitution (after bone-marrow transplantation) and may predict graft rejection (after kidney transplantation). Quantitation of human peripheral T-lymphocyte subsets from healthy volunteers and from recipients of a bone-marrow graft by a complement dependent cytotoxicity (CDC) assay, based on the use of propidium iodide, and by an indirect immunofluorescence (IIF) technique has been compared using the monoclonal antibodies OKT3, OKT4 and OKT8. Except for OKT3 in healthy individuals--for which no significant difference was found between CDC and IIF--CDC detected significantly more cells of each subset than IIF. Furthermore, the CDC results indicated the presence of low numbers of OKT4+8+ cells in the peripheral blood of healthy individuals and--with higher numbers--following marrow transplantation. Results of depletion experiments, obtained by fluorescence activated cell sorting (FACS) for either OKT4 or OKT8, supported this conclusion. OKT4/OKT8 ratios were calculated from enumerations by the CDC assay and by the IIF assay and found to be linearly related, both in healthy persons and in marrow-graft recipients. Thus, the CDC assay is a reliable method for monitoring T-cell subsets, allowing detection of lymphocytes carrying low densities of membrane determinants.

  19. Click one pot synthesis, spectral analyses, crystal structures, DFT studies and brine shrimp cytotoxicity assay of two newly synthesized 1,4,5-trisubstituted 1,2,3-triazoles (United States)

    Ahmed, Muhammad Naeem; Yasin, Khawaja Ansar; Ayub, Khurshid; Mahmood, Tariq; Tahir, M. Nawaz; Khan, Bilal Ahmad; Hafeez, Muhammad; Ahmed, Madiha; ul-Haq, Ihsan


    Methyl-2-(1-benzyl-4-phenyl-1H-1,2,3-triazol-5-yl)-2-oxoacetate (1) and ethyl-2-(1-benzyl-4-phenyl-1H-1,2,3-triazol-5-yl)-2-oxoacetate (2) were synthesized by one pot three component strategy, and characterized by FT-IR, NMR (1H and 13C) spectroscopy and TOF-MS spectrometry. Finally, the structures were unequivocally confirmed by single crystal X-ray diffraction analyses. Both compounds, 1 and 2 exist in monoclinic crystal packing having space group P21/n and P21/c, respectively. Crystal structures investigations revealed that the molecular structures of the title compounds are stabilized by weak intermolecular hydrogen bonding interactions to form dimers. Density functional theory (DFT) calculations were performed not only to compare with the experimental spectroscopic results but also to probe structural properties. The molecular electrostatic potential (MEP) mapped over the entire stabilized geometries of the molecules delivered information about the electrophilic and nucleophilic sites. Furthermore, frontier molecular orbital analysis gave the idea about stability and reactivity of compounds. Both compounds were also screened for brine shrimp cytotoxicity assay.

  20. Effects on DNA repair in human lymphocytes exposed to the food dye tartrazine yellow. (United States)

    Soares, Bruno Moreira; Araújo, Taíssa Maíra Thomaz; Ramos, Jorge Amando Batista; Pinto, Laine Celestino; Khayat, Bruna Meireles; De Oliveira Bahia, Marcelo; Montenegro, Raquel Carvalho; Burbano, Rommel Mario Rodríguez; Khayat, André Salim


    Tartrazine is a food additive that belongs to a class of artificial dyes and contains an azo group. Studies about its genotoxic, cytotoxic and mutagenic effects are controversial and, in some cases, unsatisfactory. This work evaluated the potential in vitro cytotoxicity, genotoxicity and effects on DNA repair of human lymphocytes exposed to the dye. We assessed the cytotoxicity of tartrazine by 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide test and the response of DNA repair through comet assay (alkaline version). We used different concentrations of the dye, ranging from 0.25-64.0 mM. The results demonstrated that tartrazine has no cytotoxic effects. However, this dye had a significant genotoxic effect at all concentrations tested. Although most of the damage was amenable to repair, some damage remained higher than positive control after 24 h of repair. These data demonstrate that tartrazine may be harmful to health and its prolonged use could trigger carcinogenesis.

  1. Structure-cytotoxicity relationships for dietary flavonoids

    DEFF Research Database (Denmark)

    Breinholt, V.; Dragsted, L.O.


    The cytotoxicity of a large series of dietary flavonoids was tested in a non-tumorigenic mouse and two human cancer cell lines, using the neutral red dye exclusion assay. All compounds tested exhibited a concentration-dependent cytotoxic action in the employed cell lines. The relative cytotoxicity...... of the flavonoids, however, Tvas found to vary greatly among the different cell Lines. With a few exceptions, the investigated flavonoids were more cytotoxic to the human cancer cell lines, than the mouse cell line. The differences in cytotoxicity were accounted for in part by differences in cellular uptake...... and metabolic capacity among the different cell types. In 3T3 cells fairly consistent structure-cytotoxicity relationships were found. The most cytotoxic structures tested in 3T3 cells were flavonoids with adjacent 3',4' hydroxy groups on the B-ring, such as luteolin, quercetin, myricetin, fisetin, eriodictyol...

  2. Studying the impact of S9 on cyto-genotoxicity of cigarette smoke in human peripheral blood lymphocytes in vitro. (United States)

    Jianlin, Lou; Guohai, Chu; Guojun, Zhou; Jian, Jiang; Fangfang, Huang; Juanjuan, Xu; Shu, Zheng; Zhijian, Chen; Wei, Jiang; Yezhen, Lu; Xiaoxue, Li; Jiliang, He


    In present study, human lymphocytes were exposed to cigarette smoke condensates (CSCs) at the doses of 25, 50, 75, 100 and 125 μg ml(-1) with and without S9, and the cyto-genotoxic effects were detected with CCK-8, cell apoptosis and micronucleus assays. DNA repair kinetics was observed with comet assay. Our results indicated that the cell viability decreased with CSCs doses, the percentages of apoptosis cell and the frequencies of micronuclei increased with CSCs doses, and DNA damage of human lymphocytes induced by CSCs could be basically repaired within 240 min. However, the cytotoxicity induced by CSCs +S9 was significantly lower than that induced by CSCs -S9 in CCK-8 and cell apoptosis assays, and the DNA repair speed in +S9 group was quicker than that in -S9 group. In conclusion, S9 may affect not only the cyto-genotoxicity of CSCs but also the repair process of DNA damage induced by CSCs in lymphocytes.

  3. A Novel Natural Product, KL-21, Inhibits Proliferation and Induces Apoptosis in Chronic Lymphocytic Leukemia Cells

    Directory of Open Access Journals (Sweden)

    Aysun Adan Gökbulut


    Full Text Available INTRODUCTION: The aims of this study were to examine the cytotoxic and apoptotic effects of KL-21, a novel plant product (produced by Naturin Natural Products, İzmir, Turkey, on 232B4 chronic lymphocytic leukemia (CLL cells and to determine the cytotoxic effects on healthy BEAS-2B human bronchial epithelial cells. METHODS: The cytotoxic effect of KL-21 was determined by MTT cell proliferation assay. Changes in caspase-3 enzyme activity were measured using the caspase-3 colorimetric assay. Changes in mitochondrial membrane potential were determined using the JC-1 dye-based method. Annexin V-FITC/PI double staining was performed to measure the apoptotic cell population. Effects of KL-21 on cell cycle profiles of CLL cells were investigated by flow cytometry. RESULTS: We detected time- and concentration-dependent increases in the cytotoxic effect of KL-21 on 232B4 CLL cells. However, we also showed that, especially at higher concentrations, KL-21 was less cytotoxic towards BEAS-2B healthy cells than towards CLL cells. Annexin-V/PI double staining results showed that the apoptotic cell population increased in 232B4 cells. Increasing concentrations of KL-21 increased caspase-3 enzyme activity and induced loss of mitochondrial membrane potential. KL-21 administration resulted in small increases in the percentage of the cells in the G0/G1 phase while it decreased the S phase cell population up to 1 mg/mL. At the highest concentration, most of the cells accumulated in the G0/G1 phase. DISCU