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Mobin Karimi - One of the best experts on this subject based on the ideXlab platform.

  • measuring cytotoxicity by bioluminescence imaging outperforms the standard Chromium 51 Release Assay
    PLOS ONE, 2014
    Co-Authors: Mobin Karimi, Taku Kambayashi, Michael H Bachmann, Ana M Salicioni, Edward M. Behrens, Cynthia L Baldwin
    Abstract:

    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.

Cynthia L Baldwin - One of the best experts on this subject based on the ideXlab platform.

  • Measuring Cytotoxicity by Bioluminescence Imaging Outperforms the Standard Chromium-51 Release Assay
    2016
    Co-Authors: Mobin A. Karimi, Taku Kambayashi, Michael H Bachmann, Ana M Salicioni, Edward M. Behrens, Eric Lee, Cynthia L Baldwin
    Abstract:

    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 tha

  • measuring cytotoxicity by bioluminescence imaging outperforms the standard Chromium 51 Release Assay
    PLOS ONE, 2014
    Co-Authors: Mobin Karimi, Taku Kambayashi, Michael H Bachmann, Ana M Salicioni, Edward M. Behrens, Cynthia L Baldwin
    Abstract:

    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.

  • Comparison of cytotoxicity obtained at 4 hours by the Chromium Release and BLI method.
    2014
    Co-Authors: Mobin A. Karimi, Taku Kambayashi, Michael H Bachmann, Ana M Salicioni, Edward M. Behrens, Eric Lee, Cynthia L Baldwin
    Abstract:

    Luciferase-transduced human and mouse cell lines were co-cultured with human or mouse effector cells for 4 hours at various E: T ratios. The % specific lysis of the human cell lines, (A) K562, (B) U266, and (C) UCI101 obtained by the Chromium Release Assay (closed circles) or the BLI Assay (open circles) is plotted against multiple E:T ratios. The % specific lysis of the murine cell lines, (D) P815, (E) YAC1, (F) EL-4, and (G) A20 obtained by the Chromium Release Assay (closed circles) or the BLI Assay (open circles) is plotted against multiple E:T ratios. Results are represented as mean ± SD of n = 3 independent experiments. The p values obtained from the statistical analysis performed by permutated two-way ANOVA are shown in each graph.

  • Comparison of cytotoxicity obtained at 2 hours by the Chromium Release method and BLI method.
    2014
    Co-Authors: Mobin A. Karimi, Taku Kambayashi, Michael H Bachmann, Ana M Salicioni, Edward M. Behrens, Eric Lee, Cynthia L Baldwin
    Abstract:

    Luciferase-transduced human and mouse cell lines were co-cultured with human or mouse effector cells for 2 hours at various E:T ratios. The % specific lysis of the human cell lines, (A) K562, (B) U266, and (C) UCI101 obtained by the Chromium Release Assay (closed circles) or the BLI Assay (open circles) is plotted against multiple E:T ratios. The % specific lysis of the human cell lines, (D) P815, (E) YAC1, (F) EL-4, and (G) A20 obtained by the Chromium Release Assay (closed circles) or the BLI Assay (open circles) is plotted against multiple E:T ratios. Results are represented as mean ± SD of n = 3 independent experiments. The p values obtained from the statistical analysis performed by permutated two-way ANOVA are shown in each graph.

  • Comparison of cytotoxicity obtained at 4 hours by the Chromium Release and BLI method at higher E:T ratios.
    2014
    Co-Authors: Mobin A. Karimi, Taku Kambayashi, Michael H Bachmann, Ana M Salicioni, Edward M. Behrens, Eric Lee, Cynthia L Baldwin
    Abstract:

    Luciferase-transduced the YAC1 cell line was co-cultured with mouse effector cells for 4 hours at various E:T ratios ranging from 100∶1 to 20∶1. The % specific lysis obtained by the Chromium Release Assay (closed circles) or the BLI Assay (open circles) is plotted against multiple E:T ratios. Results are represented as mean ± SD of triplicate values. One representative of 2 independent experiments is shown. The p value obtained from the statistical analysis performed permutated two-way ANOVA is shown.

Liangyen Wang - One of the best experts on this subject based on the ideXlab platform.

  • natural killer cell activity in patients with liver cirrhosis relative to severity of liver damage
    Digestive Diseases and Sciences, 1991
    Co-Authors: Wanlong Chuang, Wenyu Chang, Shinncherng Chen, Mingyuh Hsieh, Liangyen Wang
    Abstract:

    To evaluate the role of severe liver damage on natural killer cell activity, 29 patients with liver cirrhosis were examined. The natural killer cell activity was measured with a 4-hr Chromium Release Assay, and the K562 cell line was employed as target cells. The natural killer cell activity was significantly decreased in cirrhotic patients compared with normal controls and patients with chronic active hepatitis. Cirrhotic patients with Pugh's C grade of severity of liver disease had lower natural killer cell activity. The depression of natural killer cell activity in cirrhotic patients was inversely correlated with prothrombin time ratios, and the natural killer cell activity in cirrhotic patients with hepatic encephalopathy was lower than in patients without hepatic encephalopathy. Thus, the diminished natural killer cell activity in cirrhotic patients might be related to the severity of liver damage.

Katsuhiko Sato - One of the best experts on this subject based on the ideXlab platform.

  • quantifying the stress induced by distress in patients with lumbar disc herniation in terms of natural killer cell activity measurements Chromium Release Assay versus multiparameter flow cytometric Assay
    Spine, 2002
    Co-Authors: Naoto Sato, Shinichi Kikuchi, Katsuhiko Sato
    Abstract:

    Study design A comparative study was conducted. Objectives To attempt quantification of the stress in patients with lumbar disc herniation by measuring natural killer cell activity, and to evaluate the Assay methodology. Summary of background data Stressful events may have adverse effects on health. Distress in the patient with lumbar disc herniation also may be a stressful event. Previous findings have shown the activity of natural killer cells to be impaired in medical student volunteers and after bereavement or other stressful life events. However, the stress in patients with spinal disorders has not been evaluated. The standard Assay for natural killer cell activity has been the Chromium Release Assay. However, this Assay requires the use of radioactive Chromium. Flow cytometric Assay is a nonradioactive method that analyzes the activated natural killer lymphocyte subsets: CD45+, CD56+, CD69+. Methods Peripheral blood lymphocytes were obtained from 20 patients with lumbar disc herniation (mean age, 30.8 years) and 20 healthy individuals (mean age, 38.9 years). Both Chromium Release Assay and flow cytometric Assay were performed for each patient. Results The mean natural killer cell activity in the patients (8.0% +/- 4.3%) was significantly lower than in the 20 healthy adult volunteers (12.6% +/- 4.5%). The mean natural killer cell activity in the healthy volunteers was 12.6% +/- 4.5% for the Chromium Release Assay and 11.0% +/- 4.1% for the flow cytometric Assay. The correlation (r = 0.77) of natural killer cell activity between the two methods was high. Conclusions Natural killer cell activity in the patients with lumbar disc herniation was significantly lower than in healthy individuals, and the stress induced by pain and other distress may be present in patients with lumbar disc herniation. For measuring natural killer cell activity, flow cytometric Assay is a reproducible Assay, and it may be a viable alternative to the standard Chromium Release Assay.

Nina D Russell - One of the best experts on this subject based on the ideXlab platform.

  • safety and immunogenicity of cytotoxic t lymphocyte poly epitope dna plasmid ep hiv 1090 vaccine in healthy human immunodeficiency virus type 1 hiv 1 uninfected adults
    Vaccine, 2008
    Co-Authors: Geoffrey J Gorse, Guido Ferrari, Lindsey R Baden, Margaret Wecker, Mark J Newman, Kent J Weinhold, Brian D Livingston, Tonya Villafana, Elizabeth A Noonan, Nina D Russell
    Abstract:

    Summary We evaluated EP HIV-1090 vaccine, a DNA plasmid encoding 21 cytotoxic T-lymphocyte (CTL) epitopes of human immunodeficiency virus type 1 (HIV-1) and the pan-DR helper T-lymphocyte epitope (PADRE), in a dose escalation, randomized, double-blinded, placebo-controlled Phase 1 trial. Vaccine, at 0.5, 2.0, or 4.0 mg doses, or placebo was injected four times over 6 months. Forty-two healthy, HIV-1-uninfected adults were enrolled. Using an interferon-γ ELISPOT Assay, a response to PADRE was detected in one vaccine recipient. Three vaccine recipients raised anti-HIV-1 CD8+ CTL measured by Chromium-Release Assay. The vaccine was safe and well-tolerated, but only weakly immunogenic.