Antimicrobial resistance gene expression associated with multidrug resistant Salmonella spp. isolated from retail meat in Hanoi, Vietnam

The purpose of this study was to further characterize the multi-antimicrobial resistance and antibiotic resistance gene expression associated with multi-drug resistance (MDR) in Salmonella spp. isolates from retail meats in Hanoi, Vietnam. A total of 14 Salmonella spp. belonging to 9 serotypes (e.g., Warragul, London, Derby, Indiana, Meleagridis, Give, Rissen, Assine, and Typhimurium) were tested for sensitivity to 8 antibiotics. Resistance to at least one antibiotic was shown in 13 strains (92.85%). The multiple antimicrobial resistances accounted for 64.29% of isolates (9/14). One hundred percent of MDR isolates possessed antibiotic resistant genes, in which 17, 16 and 11 genes were found in Salmonella (Salm) Typhimurium S360, S384, S181 respectively; 12 genes in each strain as Indiana, Warragul, and Meleagridis; 11 genes in Give, 8 genes in Derby and 6 genes in Rissen. Three antibiotic resistance genes (ssaQ, aadA, and gyrB) were present in all isolates, whereas Cephalosporin-resistant gene (e.g., CTX-M3-like) was not detected in any isolates. The results suggest that retail meats could constitute a source of human exposure to multi-drug resistant Salmonella and future research should focus on the impact of these MDR source on the human genome. [Int Microbiol 20(2): 85-93 (2017)]Keywords: Salmonella spp. · multidrug resistance · retail mea

Sous-ensembles de cellules Natural Killer dans les maladies hématologiques : apprentissage pour l'immunothérapie

Natural Killer (NK) cells are innate cytotoxic lymphocytes that play an important role in immune control of tumor cell formation and virus infection. In healthy people, NK cell represents heterogeneous populations defined by different phenotypical markers and performing specific functions. NK cells from patients with neoplastic malignancies and viral infection are however typically distinctive from healthy people by the appearance of NK cell subsets, which are differentiated by their CD45 isoform profile. CD45 is a common-leukocyte tyrosine phosphatase abundantly expressed on all nucleated hematopoietic immune cells. Alternative splicing variant resulted in generation of the long-isoform CD45RA and the short-isoform CD45RO, which express differently on naïve and effector/memory T cells. Expression of CD45 isoforms on NK cells is largely unknown. We have previously shown that differential expression of CD45RA and CD45RO isoforms identified specific NK cell subsets in hematological diseases. One question remained unclear: how do these CD45RARO+ NK cell changes when their target cells disappeared? We used NK cells from patients treated with Lenalidomide and the anti-CD20 antibody Obinutuzumab to investigate this and showed a reduction in CD45RARO/CD45RO+ NK cells upon clearance of tumor cells (Chater 4). We observed the same in AML patients after chemotherapy. In this case the CD45RARO+ NK cell subset strongly correlates with trogocytosis of the monocyte/macrophage marker CD14 (Chapter 5). Immunophenotyping of NK cells from HIV-infected patients revealed the presence of CD45RAdim and CD45RO+ cells with reduced CD16 expression and total NKG2D down-modulation. In summary, NK cell from hematological cancers and HIV infection displayed dysfunctional hallmarks and analyzing CD45 isoform profile in these pathological conditions unveils these hallmarks.Finally, in order to regain the anti-tumor immune response in cancer patients, we present an efficient method for expansion of highly activated NK cells from umbilical cord blood (UCB) in vitro. These NK cells prove substantial antibody-dependent cell cytotoxicity (ADCC) when used in combination with clinical-approved monoclonal antibodies targeting various tumor antigens. This paves their use in allogeneic NK cell-based immunotherapies.Les cellules Natural Killer (NK) sont des lymphocytes cytotoxiques innés qui jouent un rôle important dans le contrôle immunitaire de la formation de cellules tumorales et de l'infection virale. Chez les personnes en bonne santé, les cellules NK représentent des populations hétérogènes définies par différents marqueurs phénotypiques et exécutant des fonctions spécifiques. Les cellules NK provenant de patients présentant des tumeurs malignes néoplasiques et une infection virale sont cependant typiquement distinctes des personnes en bonne santé par l'apparition de sous-ensembles de cellules NK, qui sont différenciées par leur profil d'isoformes CD45. CD45 est une tyrosine phosphatase leucocytaire commune abondamment exprimée sur toutes les cellules immunitaires hématopoïétiques nucléées. Un variant d'épissage alternatif a entraîné la génération de l'isoforme CD45RA longue et de l'isoforme courte CD45RO, qui s'expriment différemment sur les cellules T naïves et effectrices / mémoires. L'expression des isoformes CD45 sur les cellules NK est largement inconnue. Nous avons précédemment montré que l'expression différentielle des isoformes CD45RA et CD45RO a identifié des sous-ensembles de cellules NK spécifiques dans les maladies hématologiques. Une question reste floue: comment ces cellules CD45RARO + NK changent-elles lorsque leurs cellules cibles disparaissent? Nous avons utilisé des cellules NK de patients traités avec Lenalidomide et l'anticorps anti-CD20 Obinutuzumab pour étudier cela et montré une réduction des cellules CD45RARO / CD45RO + NK après la clairance des cellules tumorales (Chater 4). Nous avons observé la même chose chez les patients atteints de LMA après une chimiothérapie. Dans ce cas, le sous-ensemble de cellules CD45RARO + NK est fortement corrélé avec la trogocytose du marqueur monocyte / macrophage CD14 (Chapitre 5). L'immunophénotypage de cellules NK provenant de patients infectés par le VIH a révélé la présence de cellules CD45RAdim et CD45RO + avec une expression réduite de CD16 et une diminution de la modulation NKG2D totale. En résumé, les cellules NK des cancers hématologiques et l'infection par le VIH présentaient des caractéristiques dysfonctionnelles et l'analyse du profil isoforme CD45 dans ces conditions pathologiques dévoile ces caractéristiques.Enfin, afin de retrouver la réponse immunitaire anti-tumorale chez les patients cancéreux, nous présentons une méthode efficace pour l'expansion in vitro de cellules NK hautement activées à partir du sang du cordon ombilical (UCB). Ces cellules NK prouvent une cytotoxicité cellulaire dépendante des anticorps (ADCC) importante lorsqu'elles sont utilisées en combinaison avec des anticorps monoclonaux approuvés sur le plan clinique ciblant divers antigènes tumoraux. Ceci ouvre leur utilisation dans les immunothérapies à base de cellules NK allogéniques

NK Cells Acquire CCR5 and CXCR4 by Trogocytosis in People Living with HIV-1

International audienceNK cells play a major role in the antiviral immune response, including against HIV-1. HIV-1 patients have impaired NK cell activity with a decrease in CD56dim NK cells and an increase in the CD56−CD16+ subset, and recently it has been proposed that a population of CD56+NKG2C+KIR+CD57+ cells represents antiviral memory NK cells. Antiretroviral therapy (ART) partly restores the functional activity of this lymphocyte lineage. NK cells when interacting with their targets can gain antigens from them by the process of trogocytosis. Here we show that NK cells can obtain CCR5 and CXCR4, but barely CD4, from T cell lines by trogocytosis in vitro. By UMAP (Uniform Manifold Approximation and Projection), we show that aviremic HIV-1 patients have unique NK cell clusters that include cells expressing CCR5, NKG2C and KIRs, but lack CD57 expression. Viremic patients have a larger proportion of CXCR4+ and CCR5+ NK cells than healthy donors (HD) and this is largely increased in CD107+ cells, suggesting a link between degranulation and trogocytosis. In agreement, UMAP identified a specific NK cell cluster in viremic HIV-1 patients, which contains most of the CD107a+, CCR5+ and CXCR4+ cells. However, this cluster lacks NKG2C expression. Therefore, NK cells can gain CCR5 and CXCR4 by trogocytosis, which depends on degranulation

Dissecting the NK cell population in hematological cancers confirms the presence of tumor cells and their impact on NK population function

International audienceAbstract: The lymphocyte lineage natural killer (NK) cell is part of the innate immune system and protects against pathogens and tumor cells. NK cells are the main cell effectors of the monoclonal antibodies (mAbs) that mediates antibody-dependent cell cytotoxicity (ADCC). Hence it is relevant to understand NK physiology and status to investigate the biological effect of mAbs in the clinic. NK cells are heterogeneous with multiple subsets that may have specific activity against different attacks. The presence of viral-sculpted NK cell populations has already been described, but the presence of cancer-sculpted NK cells remains unknown. Cancer induces a broad NK cell dysfunction, which has not been linked to a specific population. Here we investigated the NK cell population by Uniform Manifold Approximation and Projection (UMAP) embed maps in Hodgkin lymphoma (HL) and acute myeloid leukemia (AML) patients at diagnosis and at least 30 days after treatment, which correlates with tumor cell clearance. We found that the NK lineage largely responded to the tumor by generating antitumor NK cells and renewing the population with a subset of immature NK cells. However, we failed to identify a specific “memory-like” subset with the NK cell markers used. Moreover, in patients in relapse we found essentially the same NK populations as those found at diagnosis, suggesting that NK cells equally respond to the first or second tumor rise. Finally, we observed that previous CMV infection largely affects the tumor-associated changes in NK population, but the CMV-associated CD57+NKG2C+ NK cell population does not appear to play any role in tumor immunity

Conceptual Design of a 10 MW Multipurpose Research Reactor Using VVR-KN Fuel

The paper presents a conceptual design of a 10 MW multipurpose nuclear research reactor (MPRR) loaded with the low-enriched uranium (LEU) VVR-KN fuel type. Neutronics and burnup calculations have been performed using the REBUS-MCNP6 linkage system code and the ENDF/B-VII.0 data library. The core consists of 36 fuel assemblies: 27 standard fuel assemblies and 9 control fuel assemblies with the uranium density of 2.8 gU/cm3 and the 235U enrichment of 19.75 wt.%. The cycle length of the core is 86 effective full-power days with the excess reactivity of 9600 and 1039 pcm at the beginning of cycle and the end of cycle, respectively. The highest power rate and the highest discharged burnup of fuel assembly are 393.49 kW and 56.74% loss of 235U, respectively. Thermal hydraulics analysis has also been conducted using the PLTEMP4.2 code for evaluating the safety parameters at a steady state of the hottest channel. The maximum temperatures of coolant and fuel cladding are 66.0°C and 83.0°C, respectively. This value is lower than the design limit of 98°C for cladding temperature. Thermal fluxes at the vertical irradiation channels and the horizontal beam ports have been evaluated. The maximum thermal fluxes of 2.5 × 1014 and 8.9 ×1013 n·cm−2·s−1 are found at the neutron trap and the beryllium reflector, respectively

NK cell activation and recovery of NK cell subsets in lymphoma patients after obinutuzumab and lenalidomide treatment

International audienceObinutuzumab (OBZ) shows stronger antibody-dependent cell cytotoxicity (ADCC) compared to rituximab and improved clinical activity for treating certain CD20 neoplasia. However, the efficacy of monoclonal antibody (mAb) as a monotherapy is limited. Natural Killer (NK) cells are mediators of ADCC. Hematological cancer patients possess antitumor NK cells that are unable to control disease, possibly because they are dysfunctional. The immunomodulatory drug lenalidomide (LEN) could be a treatment to restore exhausted NK cell cytotoxic functions. The clinical trial GALEN is a Phase Ib/II study of OBZ combined with LEN for the treatment of relapsed/refractory follicular and aggressive (DLBCL and MCL) B-cell Lymphoma. During treatment, we analyzed specific aspects of NK cell biology. Treatment reversed the immature NK phenotype of patients and increased expression of NK activating receptors. Inhibitory receptors were either unchanged or decreased. There was a strong NK response at the end of the 1st cycle NK number and intracellular granzyme B (GrzB) expression decreased, degranulation increased and NK responded better to allogeneic target challenge. Moreover, the interaction of NK cells with B cell targets, measured by trogocytosis, decreased during treatment. At the end of treatment, when target cells had been wiped out, the proportion of reactive NK cells (CD69, CD45RARO, CD107a, CD19) strongly decreased. Because all patients received LEN and OBZ, it was uncertain which drug was responsible of our observations, or even if a combination of both products was necessary for the described effects on this lymphocyte lineage

Human Leukemic Cells performing Oxidative Phosphorylation (OXPHOS) Generate an Antioxidant Response Independently of Reactive Oxygen species (ROS) Production

Tumor cell metabolism is altered during leukemogenesis. Cells performing oxidative phosphorylation (OXPHOS) generate reactive oxygen species (ROS) through mitochondrial activity. To limit the deleterious effects of excess ROS, certain gene promoters contain antioxidant response elements (ARE), e.g. the genes NQO-1 and HO-1. ROS induces conformational changes in KEAP1 and releases NRF2, which activates AREs. We show in vitro and in vivo that OXPHOS induces, both in primary leukemic cells and cell lines, de novo expression of NQO-1 and HO-1 and also the MAPK ERK5 and decreases KEAP1 mRNA. ERK5 activates the transcription factor MEF2, which binds to the promoter of the miR-23a–27a–24-2 cluster. Newly generated miR-23a destabilizes KEAP1 mRNA by binding to its 3′UTR. Lower KEAP1 levels increase the basal expression of the NRF2-dependent genes NQO-1 and HO-1. Hence, leukemic cells performing OXPHOS, independently of de novo ROS production, generate an antioxidant response to protect themselves from ROS

Identification of Anti-tumor Cells Carrying Natural Killer (NK) Cell Antigens in Patients With Hematological Cancers

Natural killer (NK) cells, a cytotoxic lymphocyte lineage, are able to kill tumor cells in vitro and in mouse models. However, whether these cells display an anti-tumor activity in cancer patients has not been demonstrated. Here we have addressed this issue in patients with several hematological cancers. We found a population of highly activated CD56dimCD16+ NK cells that have recently degranulated, evidence of killing activity, and it is absent in healthy donors. A high percentage of these cells expressed natural killer cell p46-related protein (NKp46), natural-killer group 2, member D (NKG2D) and killer inhibitory receptors (KIRs) and a low percentage expressed NKG2A and CD94. They are also characterized by a high metabolic activity and active proliferation. Notably, we found that activated NK cells from hematological cancer patients have non-NK tumor cell antigens on their surface, evidence of trogocytosis during tumor cell killing. Finally, we found that these activated NK cells are distinguished by their CD45RA+RO+ phenotype, as opposed to non-activated cells in patients or in healthy donors displaying a CD45RA+RO− phenotype similar to naïve T cells. In summary, we show that CD45RA+RO+ cells, which resemble a unique NK population, have recognized tumor cells and degranulate in patients with hematological neoplasias