Changes to the Natural Killer Cell Repertoire after Therapeutic Hepatitis B DNA Vaccination

BACKGROUND: Improvements to the outcome of adaptive immune responses could be achieved by inducing specific natural killer (NK) cell subsets which can cooperate with dendritic cells to select efficient T cell responses. We previously reported the induction or reactivation of T cell responses in chronic hepatitis B patients vaccinated with a DNA encoding hepatitis B envelope proteins during a phase I clinical trial. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we examined changes in the peripheral NK cell populations occurring during this vaccine trial using flow cytometry analysis. Despite a constant number of NK cells in the periphery, a significant increase in the CD56(bright) population was observed after each vaccination and during the follow up. Among the 13 different NK cell markers studied by flow cytometry analysis, the expression of CD244 and NKG2D increased significantly in the CD56(bright) NK population. The ex vivo CD107a expression by CD56(bright) NK cells progressively increased in the vaccinated patients to reach levels that were significantly higher compared to chronically HBV-infected controls. Furthermore, modifications to the percentage of the CD56(bright) NK cell population were correlated with HBV-specific T cell responses detected by the ELISPOT assay. CONCLUSIONS/SIGNIFICANCE: These changes in the CD56(bright) population may suggest a NK helper effect on T cell adaptive responses. Activation of the innate and adaptive arms of the immune system by DNA immunization may be of particular importance to the efficacy of therapeutic interventions in a context of chronic infections. TRIAL REGISTRATION: ClinicalTrials.gov NCT00988767

Site specific and localized structural displacements in open structured multimetallic oxides

The structures of solids can locally differ from the macroscopic picture obtained by structural averaging techniques. This difference significantly influences the performance of any functional material. Measurements of these local structures are challenging. Thus, the description of defects is often disregarded. However, in order to understand the functionality, such irregularities have to be investigated. Here, we present a high resolution scanning transmission electron microscopic (STEM) study revealing local structural irregularities in open structured oxides using catalytically active orthorhombic (Mo,V,Te,Nb)Ox as a complex example. Detailed analysis of annular dark field- and annular bright field-STEM images reveal site specific local structural displacements of individual framework and channel sites in the picometer range. These experimental observables can be considered as an important structural addendum for theoretical modelling and should be implemented into the existing data in order to quantify site specific potential energies and stresses. This information can further be used to describe the impact of the structure on the catalytic performance in greater detail

Nematic suspension of a microporous layered silicate obtained by forceless spontaneous delamination via repulsive osmotic swelling for casting high-barrier all-inorganic films

Exploiting the full potential of layered materials for a broad range of applications requires delamination into functional nanosheets. Delamination via repulsive osmotic swelling is driven by thermodynamics and represents the most gentle route to obtain nematic liquid crystals consisting exclusively of single-layer nanosheets. This mechanism was, however, long limited to very few compounds, including 2:1-type clay minerals, layered titanates, or niobates. Despite the great potential of zeolites and their microporous layered counterparts, nanosheet production is challenging and troublesome, and published procedures implied the use of some shearing forces. Here, we present a scalable, eco-friendly, and utter delamination of the microporous layered silicate ilerite into single-layer nanosheets that extends repulsive delamination to the class of layered zeolites. As the sheet diameter is preserved, nematic suspensions with cofacial nanosheets of ≈9000 aspect ratio are obtained that can be cast into oriented films, e.g., for barrier applications

Immune control of HIV-1 infection after therapy interruption: immediate versus deferred antiretroviral therapy

Abstract Background The optimal stage for initiating antiretroviral therapies in HIV-1 bearing patients is still a matter of debate. Methods We present computer simulations of HIV-1 infection aimed at identifying the pro et contra of immediate as compared to deferred Highly Active Antiretroviral Therapy (HAART). Results Our simulations highlight that a prompt specific CD8+ cytotoxic T lymphocytes response is detected when therapy is delayed. Compared to very early initiation of HAART, in deferred treated patients CD8+ T cells manage to mediate the decline of viremia in a shorter time and, at interruption of therapy, the virus experiences a stronger immune pressure. We also observe, however, that the immunological effects of the therapy fade with time in both therapeutic regimens. Thus, within one year from discontinuation, viral burden recovers to the value at which it would level off in the absence of therapy. In summary, simulations show that immediate therapy does not prolong the disease-free period and does not confer a survival benefit when compared to treatment started during the chronic infection phase. Conclusion Our conclusion is that, since there is no therapy to date that guarantees life-long protection, deferral of therapy should be preferred in order to minimize the risk of adverse effects, the occurrence of drug resistances and the costs of treatment.</p

Refining Critical Structure Contouring in STereotactic Arrhythmia Radioablation (STAR): Benchmark Results and Consensus Guidelines from the STOPSTORM.eu Consortium.

BACKGROUND AND PURPOSE In patients with recurrent ventricular tachycardia (VT), STereotactic Arrhythmia Radioablation (STAR) shows promising results. The STOPSTORM consortium was established to investigate and harmonise STAR treatment in Europe. The primary goals of this benchmark study were to standardise contouring of organs at risk (OAR) for STAR, including detailed substructures of the heart, and accredit each participating centre. MATERIALS AND METHODS Centres within the STOPSTORM consortium were asked to delineate 31 OAR in three STAR cases. Delineation was reviewed by the consortium expert panel and after a dedicated workshop feedback and accreditation was provided to all participants. Further quantitative analysis was performed by calculating DICE similarity coefficients (DSC), median distance to agreement (MDA), and 95th percentile distance to agreement (HD95). RESULTS Twenty centres participated in this study. Based on DSC, MDA and HD95, the delineations of well-known OAR in radiotherapy were similar, such as lungs (median DSC=0.96, median MDA=0.1mm and median HD95=1.1mm) and aorta (median DSC=0.90, median MDA=0.1mm and median HD95=1.5mm). Some centres did not include the gastro-oesophageal junction, leading to differences in stomach and oesophagus delineations. For cardiac substructures, such as chambers (median DSC=0.83, median MDA=0.2mm and median HD95=0.5mm), valves (median DSC=0.16, median MDA=4.6mm and median HD95=16.0mm), coronary arteries (median DSC=0.4, median MDA=0.7mm and median HD95=8.3mm) and the sinoatrial and atrioventricular nodes (median DSC=0.29, median MDA=4.4mm and median HD95=11.4mm), deviations between centres occurred more frequently. After the dedicated workshop all centres were accredited and contouring consensus guidelines for STAR were established. CONCLUSION This STOPSTORM multi-centre critical structure contouring benchmark study showed high agreement for standard radiotherapy OAR. However, for cardiac substructures larger disagreement in contouring occurred, which may have significant impact on STAR treatment planning and dosimetry evaluation. To standardize OAR contouring, consensus guidelines for critical structure contouring in STAR were established

Altered Responses to Homeostatic Cytokines in Patients with Idiopathic CD4 Lymphocytopenia

Idiopathic CD4 lymphocytopenia (ICL) is a rare immune deficiency characterized by a protracted CD4+ T cell loss of unknown etiology and by the occurrence of opportunistic infections similar to those seen in AIDS. We investigated whether a defect in responses to cytokines that control CD4+ T cell homeostasis could play a role in ICL. Immunophenotype and signaling responses to interleukin-7 (IL-7), IL-2, and thymic stromal lymphopoietin (TSLP) were analyzed by flow cytometry in CD4+ T cells from 15 ICL patients and 15 healthy blood donors. The induction of phospho-STAT5 after IL-7 stimulation was decreased in memory CD4+ T cells of some ICL patients, which correlated with a decreased expression of the IL-7R\uce\ub1 receptor chain (R = 0.74, p<0.005) and with lower CD4+ T cell counts (R = 0.69, p<0.005). IL-2 responses were also impaired, both in the Treg and conventional memory subsets. Decreased IL-2 responses correlated with decreased IL-7 responses (R = 0.75, p<0.005), pointing to combined defects that may significantly perturb CD4+ T cell homeostasis in a subset of ICL patients. Unexpectedly, responses to the IL-7-related cytokine TSLP were increased in ICL patients, while they remained barely detectable in healthy controls. TSLP responses correlated inversely with IL-7 responses (R = -0.41; p<0.05), suggesting a cross-regulation between the two cytokine systems. In conclusion, IL-7 and IL-2 signaling are impaired in ICL, which may account for the loss of CD4+ T cell homeostasis. Increased TSLP responses point to a compensatory homeostatic mechanism that may mitigate defects in \uce\ub3c cytokine responses. \uc2\ua9 2013 Bugault et al

Acute mucosal pathogenesis of feline immunodeficiency virus is independent of viral dose in vaginally infected cats

<p>Abstract</p> <p>Background</p> <p>The mucosal pathogenesis of HIV has been shown to be an important feature of infection and disease progression. HIV-1 infection causes depletion of intestinal lamina propria CD4+ T cells (LPL), therefore, intestinal CD4+ T cell preservation may be a useful correlate of protection in evaluating vaccine candidates. Vaccine studies employing the cat/FIV and macaque/SIV models frequently use high doses of parenterally administered challenge virus to ensure high plasma viremia in control animals. However, it is unclear if loss of mucosal T cells would occur regardless of initial viral inoculum dose. The objective of this study was to determine the acute effect of viral dose on mucosal leukocytes and associated innate and adaptive immune responses.</p> <p>Results</p> <p>Cats were vaginally inoculated with a high, middle or low dose of cell-associated and cell-free FIV. PBMC, serum and plasma were assessed every two weeks with tissues assessed eight weeks following infection. We found that irrespective of mucosally administered viral dose, FIV infection was induced in all cats. However, viremia was present in only half of the cats, and viral dose was unrelated to the development of viremia. Importantly, regardless of viral dose, all cats experienced significant losses of intestinal CD4+ LPL and CD8+ intraepithelial lymphocytes (IEL). Innate immune responses by CD56+CD3- NK cells correlated with aviremia and apparent occult infection but did not protect mucosal T cells. CD4+ and CD8+ T cells in viremic cats were more likely to produce cytokines in response to Gag stimulation, whereas aviremic cats T cells tended to produce cytokines in response to Env stimulation. However, while cell-mediated immune responses in aviremic cats may have helped reduce viral replication, they could not be correlated to the levels of viremia. Robust production of anti-FIV antibodies was positively correlated with the magnitude of viremia.</p> <p>Conclusions</p> <p>Our results indicate that mucosal immune pathogenesis could be used as a rapid indicator of vaccine success or failure when combined with a physiologically relevant low dose mucosal challenge. We also show that innate immune responses may play an important role in controlling viral replication following acute mucosal infection, which has not been previously identified.</p

What does the structure-function relationship of the HIV-1 Tat protein teach us about developing an AIDS vaccine?

The human immunodeficiency virus type 1 (HIV-1) trans-activator of transcription protein Tat is an important factor in viral pathogenesis. In addition to its function as the key trans-activator of viral transcription, Tat is also secreted by the infected cell and taken up by neighboring cells where it has an effect both on infected and uninfected cells. In this review we will focus on the relationship between the structure of the Tat protein and its function as a secreted factor. To this end we will summarize some of the exogenous functions of Tat that have been implicated in HIV-1 pathogenesis and the impact of structural variations and viral subtype variants of Tat on those functions. Finally, since in some patients the presence of Tat-specific antibodies or CTL frequencies are associated with slow or non-progression to AIDS, we will also discuss the role of Tat as a potential vaccine candidate, the advances made in this field, and the importance of using a Tat protein capable of eliciting a protective or therapeutic immune response to viral challenge

Innate immunity against HIV: a priority target for HIV prevention research

This review summarizes recent advances and current gaps in understanding of innate immunity to human immunodeficiency virus (HIV) infection, and identifies key scientific priorities to enable application of this knowledge to the development of novel prevention strategies (vaccines and microbicides). It builds on productive discussion and new data arising out of a workshop on innate immunity against HIV held at the European Commission in Brussels, together with recent observations from the literature

CX-5461 is a DNA G-quadruplex stabilizer with selective lethality in BRCA1/2 deficient tumours.

G-quadruplex DNAs form four-stranded helical structures and are proposed to play key roles in different cellular processes. Targeting G-quadruplex DNAs for cancer treatment is a very promising prospect. Here, we show that CX-5461 is a G-quadruplex stabilizer, with specific toxicity against BRCA deficiencies in cancer cells and polyclonal patient-derived xenograft models, including tumours resistant to PARP inhibition. Exposure to CX-5461, and its related drug CX-3543, blocks replication forks and induces ssDNA gaps or breaks. The BRCA and NHEJ pathways are required for the repair of CX-5461 and CX-3543-induced DNA damage and failure to do so leads to lethality. These data strengthen the concept of G4 targeting as a therapeutic approach, specifically for targeting HR and NHEJ deficient cancers and other tumours deficient for DNA damage repair. CX-5461 is now in advanced phase I clinical trial for patients with BRCA1/2 deficient tumours (Canadian trial, NCT02719977, opened May 2016).This work was supported by the Canadian Breast Cancer Foundation BC/Yukon, BC Cancer Foundation, Stand Up to Cancer Canada (SU2C-AACR-DT-18-15), TFRI Grant 1021, CCSRI Grant 701584, CIHR Grant MOP-126119, Canada Foundation for Innovation and Cancer Research UK. Grant Brown lab is supported by CCSRI Impact Grant 702310 (to G.W.B.) and Ontario Government Scholarship (to B.H.). S.A. is supported by a Canada Research Chair in Molecular Oncology. The Balasubramanian lab is supported by a programme grant (C14303/A17197) and core funding (C14303/A17197) from Cancer Research UK