Distinct effects of IL-18 on the engraftment and function of human effector CD8 T cells and regulatory T cells

IL-18 has pleotropic effects on the activation of T cells during antigen presentation. We investigated the effects of human IL-18 on the engraftment and function of human T cell subsets in xenograft mouse models. IL-18 enhanced the engraftment of human CD8(+) effector T cells and promoted the development of xenogeneic graft versus host disease (GVHD). In marked contrast, IL-18 had reciprocal effects on the engraftment of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) in the xenografted mice. Adoptive transfer experiments indicated that IL-18 prevented the suppressive effects of Tregs on the development of xenogeneic GVHD. The IL-18 results were robust as they were observed in two different mouse strains. In addition, the effects of IL-18 were systemic as IL-18 promoted engraftment and persistence of human effector T cells and decreased Tregs in peripheral blood, peritoneal cavity, spleen and liver. In vitro experiments indicated that the expression of the IL-18Ralpha was induced on both CD4 and CD8 effector T cells and Tregs, and that the duration of expression was less sustained on Tregs. These preclinical data suggest that human IL-18 may have use as an adjuvant for immune reconstitution after cytotoxic therapies, and to augment adoptive immunotherapy, donor leukocyte infusions, and vaccine strategies.     

Glutathione and glutathione metabolizing enzymes in yeasts

Total glutathione content, glutathione peroxidase, glutathione transferase and glutathione reductase activities have been measured in 12 species of yeasts. All the strains tested contained glutathione, though in different amounts, as well as the above mentioned enzymes. To discriminate between the selenium-dependent and the selenium-independent form, glutathione peroxidase activity has been measured with both H₂O₂ and cumene hydroperoxide. Rhodotorula glutinis appeared to be the only strain in which the selenium-dependent form was not found, but this yeast exhibited the highest level of selenium-independent glutathione peroxidase activity as compared to the other strains.     

The CDK4/6 Inhibitor Abemaciclib Induces a T Cell Inflamed Tumor Microenvironment and Enhances the Efficacy of PD-L1 Checkpoint Blockade

1. Download high-res image (224KB)
2. Download full-size image

     

HIV-1 Nef promotes migration and chemokine synthesis of human basophils and mast cells through the interaction with CXCR4

Background

The Nef protein can be detected in plasma of HIV-1-infected patients and plays a role in the pathogenesis of HIV-1. Nef produced during the early stages of infection is fundamental in creating the ideal environment for viral replication, e.g. by reducing the ability of infected cells to induce an immune response.

Aim

Based on previous experience showing that both Tat and gp41 of HIV-1 are potent chemotactic factors for basophils and mast cells, and gp120 is a powerful stimulus for the release of histamine and cytokines (IL-4 and IL-13) from basophils, in this study we aimed to verify if the HIV Nef protein can exert some effects on basophils and mast cells purified from healthy volunteers through the interaction with the CXCL12 receptor, CXCR4.

Methods

Basophils purified from peripheral blood cells of 30 healthy volunteers and mast cells obtained from lung tissue of ten healthy volunteers were tested by flow cytometric analysis, chemotaxis and chemokine production by ELISA assays.

Results

Nef is a potent chemoattractant for basophils and lung mast cells obtained from healthy, HIV-1 and HIV-2 seronegative individuals. Incubation of basophils and mast cells with Nef induces the release of chemokines (CXCL8/IL-8 and CCL3/MIP-1α). The chemotactic activity of Nef on basophils and mast cells is mediated by the interaction with CXCR4 receptors, being blocked by preincubation of FcεRI⁺ cells with an anti-CXCR4 Ab. Stimulation with Nef or CXCL12/SDF-1α, a CXCR4 ligand, desensitizes basophils to a subsequent challenge with an autologous or heterologous stimulus.

Conclusions

These results indicate that Nef, a HIV-1-encoded α-chemokine homolog protein, plays a direct role in basophils and mast cell recruitment and activation at sites of HIV-1 replication, by promoting directional migration of human FcεRI⁺ cells and the release of chemokines from these cells. Together with our previous results, these data suggest that FcεRI⁺ cells contribute to the dysregulation of the immune system in HIV-1 infection.

     

Impact of Safety-Related Dose Reductions or Discontinuations on Sustained Virologic Response in HCV-Infected Patients: Results from the GUARD-C Cohort

Background

Despite the introduction of direct-acting antiviral agents for chronic hepatitis C virus (HCV) infection, peginterferon alfa/ribavirin remains relevant in many resource-constrained settings. The non-randomized GUARD-C cohort investigated baseline predictors of safety-related dose reductions or discontinuations (sr-RD) and their impact on sustained virologic response (SVR) in patients receiving peginterferon alfa/ribavirin in routine practice.

Methods

A total of 3181 HCV-mono-infected treatment-naive patients were assigned to 24 or 48 weeks of peginterferon alfa/ribavirin by their physician. Patients were categorized by time-to-first sr-RD (Week 4/12). Detailed analyses of the impact of sr-RD on SVR24 (HCV RNA <50 IU/mL) were conducted in 951 Caucasian, noncirrhotic genotype (G)1 patients assigned to peginterferon alfa-2a/ribavirin for 48 weeks. The probability of SVR24 was identified by a baseline scoring system (range: 0–9 points) on which scores of 5 to 9 and <5 represent high and low probability of SVR24, respectively.

Results

SVR24 rates were 46.1% (754/1634), 77.1% (279/362), 68.0% (514/756), and 51.3% (203/396), respectively, in G1, 2, 3, and 4 patients. Overall, 16.9% and 21.8% patients experienced ≥1 sr-RD for peginterferon alfa and ribavirin, respectively. Among Caucasian noncirrhotic G1 patients: female sex, lower body mass index, pre-existing cardiovascular/pulmonary disease, and low hematological indices were prognostic factors of sr-RD; SVR24 was lower in patients with ≥1 vs. no sr-RD by Week 4 (37.9% vs. 54.4%; P = 0.0046) and Week 12 (41.7% vs. 55.3%; P = 0.0016); sr-RD by Week 4/12 significantly reduced SVR24 in patients with scores <5 but not ≥5.

Conclusions

In conclusion, sr-RD to peginterferon alfa-2a/ribavirin significantly impacts on SVR24 rates in treatment-naive G1 noncirrhotic Caucasian patients. Baseline characteristics can help select patients with a high probability of SVR24 and a low probability of sr-RD with peginterferon alfa-2a/ribavirin.     

Ultrastructural changes associated with the accumulation and secretion of sanguinarine in Papaver bracteatum suspension cultures treated with fungal elicitor

Suspension cultures of Papaver bracteatum Arya II Lindl., grown without hormone in the presence of conidial extracts of Verticillium dahliae Kleb., accumulate millimolar quantities of the benzophenanthridine alkaloid, sanguinarine. Under the fluorescence microscope, the elicitor-treated cells display an orange-yellow fluorescence characteristic of sanguinarine, primarily near the periphery of the cells. Electron-microscopic inspection showed the presence of slightly dilated endoplasmic reticulum and of electron-dense protuberances on the tonoplast of large central vacuoles. These osmiophilic aggregates lining the tonoplast bud into spherical bodies, appear to become detached from the membrane and are released into the vacuole. Upon subcellular fractionation of elicited cells on Renografin step gradients, sanguinarine was found to be distributed in all bands but with 86% concentrated in the gradient pellet. Analysis of the pellet by electron microscopy showed that it contained electron-dense fragments similar to the osmiophilic bodies observed on the tonoplast of intact elicited cells. In elicited cell cultures, most of the sanguinarine was recovered from medium in a 100·g sedimenting, cell-free, particulate fraction accounting for as much as 85% of the media sanguinarine and 62% of the total sanguinarine. The sanguinarine-rich 100·g media pellet was determined to be two-thirds protein, one-third RNA and was essentially devoid of phenolics, phospholipid and DNA. The pellet consisted of electrondense material and cytoplasmic remnants resembling those found in the Renografin pellet and tonoplast aggregates of intact cells. When placed under hypotonic conditions or extracted with aqueous buffer, pH 3–11, the pellet did not release sanguinarine. These observations provide evidence for storage of sanguinarine at electron-dense deposits which occur on the tonoplast and as freely floating bodies in vacuoles.Abbreviations BA N⁶-benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - EM electron microscopy - ER endoplasmic reticulum - HPLC high-pressure liquid chromatography - MRST Murashige and Skoog's revised tobacco medium     

Implication of tyramine in the biosynthesis of morphinan alkaloids in Papaver

Doubly-labeled [³H, ¹⁴C]tyrosines, [1-¹³C-]tyramine or [2-¹⁴C]tyramine, administered to the stems of intact Papaver somniferum L. plants, were found to be incorporated into the morphinan alkaloids of the plant with comparable efficiency. ³H/¹⁴C ratios of alkaloids from plants fed the tyrosines were consistent with an almost equal conversion of this amino acid into the tetrahydroisoquinoline (TIQ) and benzyl-derived segments. Nuclear magnetic resonance (NMR) analyses of morphine isolated after administration of [1-¹³C]tyramine demonstrated selective labeling of C-16 of the alkaloid, indicating the conversion of this amine primarily into the TIQ-derived moiety. Morphine and thebaine labeled by [2-¹⁴C]tyramine were degraded to phenanthridines and N,N-dimethyl ethylamines. Of the total radioactivity in the alkaloids 97% was found to be associated with the ethylamines, a distribution consistent with the NMR data. This preferential utilization of tyramine in the biosynthesis of morphinan alkaloids can be explained by the compartmentalization of intermediates and enzymes of the pathway.Abbreviations L-dopa L-3,4-dihydroxyphenylalanine - HPLC high-pressure liquid chromatography - NMR nuelear magnetic resonance - TIQ tetrahydroisoquinoline     

Lymph node fine‐needle cytology in the era of personalised medicine. Is there a role?

The 2016 World Health Organisation revised classification of lymphoma has sub‐classified well‐defined entities and added a number of provisional entities on the basis of new knowledge on genetic, epigenetics and phenotypical data; prognostic and predictive features are also part of this classification. New knowledge on well‐defined entities further enlightens the mechanisms of lymphomagenesis, which are more complex and multifactorial than once believed. Therapies are also more complex because traditional clinical trials have been integrated with new drugs and compounds with unique mechanisms of actions against distinct molecular targets. As lymphoma acquires additional genetic and phenotypic features over the time, pathological assessment is also necessary. Histological evaluation and tissue collection by surgical biopsies are necessary for phenotypical and molecular purposes; however, these are demanding procedures for both the patient and the health care system. At the same time, the choice of the best treatment for a specific entity, in different phases and different patients requires information that may not be available when the biopsy is performed. Fine needle aspiration cytology (FNAC) is successfully used in lymph nodes (LNs) in combination with different ancillary techniques and might be used to assess the phenotypic and genetic profile of specific targets and to get key information for therapy, in different phases and stages of the disease, with the option to re‐check the same target over time, without surgical excision. This brief review describes LN‐FNAC diagnostic criteria, current therapies for lymphomas and the potential role of LN‐FNAC in selecting non‐Hodgkin lymphomas patients for specific targeted treatments.