Apoptosis of Rat Uterine NK Cells In Vitro.

Restrictions on the use of antibiotics in the poultry industry stimulate the development of alternative nutritional solutions to maintain or improve poultry health. This requires more insight in the modulatory effects of feed additives on the immune system and microbiota composition. Compounds known to influence the innate immune system and microbiota composition were selected and screened in vitro, in ovo, and in vivo. Among all compounds, 57 enhanced NK cell activation, 56 increased phagocytosis, and 22 increased NO production of the macrophage cell line HD11 in vitro. Based on these results, availability and regulatory status, six compounds were selected for further analysis. None of these compounds showed negative effects on growth, hatchability, and feed conversion in in ovo and in vivo studies. Based on the most interesting numerical results and highest future potential feasibility, two compounds were analyzed further. Administration of glucose oligosaccharide and long-chain glucomannan in vivo both enhanced activation of intraepithelial NK cells and led to increased relative abundance of lactic acid bacteria (LAB) amongst ileum and ceca microbiota after seven days of supplementation. Positive correlations between NK cell subsets and activation, and relative abundance of LAB suggest the involvement of microbiota in the modulation of the function of intraepithelial NK cells. This study identifies glucose oligosaccharide and long-chain glucomannan supplementation as effective nutritional strategies to modulate the intestinal microbiota composition and strengthen the intraepithelial innate immune system.

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IMMU-47. PROTEIN PHOSPHATASE 2A INHIBITION IN NK CELL THERAPY FOR TREATMENT OF MEDULLOBLASTOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa215.477 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii115-ii115

Author(s):

Rongze Olivia Lu ◽

Winson Ho ◽

Brandon Chiou

Keyword(s):

Nk Cells ◽

Cell Line ◽

Protein Phosphatase ◽

Nk Cell ◽

Protein Phosphatase 2A ◽

T Cell Response ◽

Intrinsic Activity ◽

Cd107a Expression ◽

Phosphatase 2A

Abstract Checkpoint immunotherapy (ICB) thus far has shown limited efficacy against brain tumors, such as medulloblastoma (MB). Its low mutational burden is thought to result in a paucity of neoantigen to trigger an effective T-cell response. Natural killer (NK) cells, can recognize tumor cells independently of neoantigens, making them appealing against MBs. Modulation of NK cells to enhance cytotoxicity against MBs could be a novel treatment strategy. Protein Phosphatase 2A (PP2A), a ubiquitous serine/threonine phosphatase, has been shown to inhibit IFNg and Granzyme B production by NK cells. We hypothesize that NK92, a transformed human NK cell line, has intrinsic activity against human MB cells and that inhibiting PP2A pharmacologically can enhance cytotoxicity of NK92 cells. We performed NK cytotoxicity assay and granulation assay against human MB cell line D425. We also used a small molecular inhibitor, LB100, to modulate PP2A activity in NK92. NK92 cells were co-cultured with D425, in increasing E:T (Effector:Target) ratio for 4 hours. D425 cells were pre-labeled with CellTrace Violet dye. The percentage of D425 (Violet+) cells in apoptosis (Cas3/7+) or necrosis (AAD+) were compared with different ET ratios to quantify NK mediated cell cytotoxicity. We also measured CD107a expression in NK92 to assess granulation with LB100 treatment. D425 cells were sensitive to NK92 killing. Percentage of D425 cells either apoptotic or necrotic increased with increasing ET ratio, suggesting that there was NK92 mediated cytotoxicity. Percentage of killed D425 cells ranged from 18% at baseline (without NK92) to 80% at ET ratio of 20. Inhibition of PP2A using LB100, enhanced NK92 degranulation. CD107a+ NK92 cells increased from 19% to 28% with 8uM of LB100. NK92 cells are cytotoxic against MB cells in vitro and inhibition of PP2A in NK cells can enhance their activity against MB cells.

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A bispecific antibody agonist of the IL-2 heterodimeric receptor preferentially promotes in vivo expansion of CD8 and NK cells

Scientific Reports ◽

10.1038/s41598-021-90096-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Katherine E. Harris ◽

Kyle J. Lorentsen ◽

Harbani K. Malik-Chaudhry ◽

Kaitlyn Loughlin ◽

Harish Medlari Basappa ◽

...

Keyword(s):

T Cells ◽

Nk Cells ◽

Bispecific Antibody ◽

T Regulatory Cells ◽

Tumor Regression ◽

Interleukin 2 ◽

In Vivo Studies ◽

Preferential Binding

AbstractThe use of recombinant interleukin-2 (IL-2) as a therapeutic protein has been limited by significant toxicities despite its demonstrated ability to induce durable tumor-regression in cancer patients. The adverse events and limited efficacy of IL-2 treatment are due to the preferential binding of IL-2 to cells that express the high-affinity, trimeric receptor, IL-2Rαβγ such as endothelial cells and T-regulatory cells, respectively. Here, we describe a novel bispecific heavy-chain only antibody which binds to and activates signaling through the heterodimeric IL-2Rβγ receptor complex that is expressed on resting T-cells and NK cells. By avoiding binding to IL-2Rα, this molecule circumvents the preferential T-reg activation of native IL-2, while maintaining the robust stimulatory effects on T-cells and NK-cells in vitro. In vivo studies in both mice and cynomolgus monkeys confirm the molecule’s in vivo biological activity, extended pharmacodynamics due to the Fc portion of the molecule, and enhanced safety profile. Together, these results demonstrate that the bispecific antibody is a safe and effective IL-2R agonist that harnesses the benefits of the IL-2 signaling pathway as a potential anti-cancer therapy.

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Microfluidic tumor-on-a-chip model to evaluate the role of tumor environmental stress on NK cell exhaustion

Science Advances ◽

10.1126/sciadv.abc2331 ◽

2021 ◽

Vol 7 (8) ◽

pp. eabc2331 ◽

Cited By ~ 1

Author(s):

Jose M. Ayuso ◽

Shujah Rehman ◽

Maria Virumbrales-Munoz ◽

Patrick H. McMinn ◽

Peter Geiger ◽

...

Keyword(s):

Nk Cells ◽

Immune Cells ◽

Molecular Mechanisms ◽

Nk Cell ◽

Checkpoint Inhibitors ◽

Waste Product ◽

Extended Period ◽

Cell Exhaustion

Solid tumors generate a suppressive environment that imposes an overwhelming burden on the immune system. Nutrient depletion, waste product accumulation, hypoxia, and pH acidification severely compromise the capacity of effector immune cells such as T and natural killer (NK) cells to destroy cancer cells. However, the specific molecular mechanisms driving immune suppression, as well as the capacity of immune cells to adapt to the suppressive environment, are not completely understood. Thus, here, we used an in vitro microfluidic tumor-on-a-chip platform to evaluate how NK cells respond to the tumor-induced suppressive environment. The results demonstrated that the suppressive environment created by the tumor gradually eroded NK cell cytotoxic capacity, leading to compromised NK cell surveillance and tumor tolerance. Further, NK cell exhaustion persisted for an extended period of time after removing NK cells from the microfluidic platform. Last, the addition of checkpoint inhibitors and immunomodulatory agents alleviated NK cell exhaustion.

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