Highly Differentiated, Resting Gn-Specific Memory CD8+ T Cells Persist Years after Infection by Andes Hantavirus

In man, infection with South American Andes virus (ANDV) causes hantavirus cardiopulmonary syndrome (HCPS). HCPS due to ANDV is endemic in Southern Chile and much of Argentina and increasing numbers of cases are reported all over South America. A case-fatality rate of about 36% together with the absence of successful antiviral therapies urge the development of a vaccine. Although T-cell responses were shown to be critically involved in immunity to hantaviruses in mouse models, no data are available on the magnitude, specificity and longevity of ANDV-specific memory T-cell responses in patients. Using sets of overlapping peptides in IFN-γ ELISPOT assays, we herein show in 78 Chilean convalescent patients that Gn-derived epitopes were immunodominant as compared to those from the N- and Gc-proteins. Furthermore, while the relative contribution of the N-specific response significantly declined over time, Gn-specific responses remained readily detectable ex vivo up to 13 years after the acute infection. Tetramer analysis further showed that up to 16.8% of all circulating CD3+CD8+ T cells were specific for the single HLA-B*3501-restricted epitope Gn465–473 years after the acute infection. Remarkably, Gn465–473–specific cells readily secreted IFN-γ, granzyme B and TNF-α but not IL-2 upon stimulation and showed a ‘revertant’ CD45RA+CD27−CD28−CCR7−CD127− effector memory phenotype, thereby resembling a phenotype seen in other latent virus infections. Most intriguingly, titers of neutralizing antibodies increased over time in 10/17 individuals months to years after the acute infection and independently of whether they were residents of endemic areas or not. Thus, our data suggest intrinsic, latent antigenic stimulation of Gn-specific T-cells. However, it remains a major task for future studies to proof this hypothesis by determination of viral antigen in convalescent patients. Furthermore, it remains to be seen whether Gn-specific T cells are critical for viral control and protective immunity. If so, Gn-derived immunodominant epitopes could be of high value for future ANDV vaccines

Activation of the P2X7 ion channel by soluble and covalently bound ligands

The homotrimeric P2X7 purinergic receptor has sparked interest because of its capacity to sense adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide (NAD) released from cells and to induce calcium signaling and cell death. Here, we examine the response of arginine mutants of P2X7 to soluble and covalently bound ligands. High concentrations of ecto-ATP gate P2X7 by acting as a soluble ligand and low concentrations of ecto-NAD gate P2X7 following ADP-ribosylation at R125 catalyzed by toxin-related ecto-ADP-ribosyltransferase ART2.2. R125 lies on a prominent cysteine-rich finger at the interface of adjacent receptor subunits, and ADP-ribosylation at this site likely places the common adenine nucleotide moiety into the ligand-binding pocket of P2X7

Trihydrophobin 1 Phosphorylation by c-Src Regulates MAPK/ERK Signaling and Cell Migration

c-Src activates Ras-MAPK/ERK signaling pathway and regulates cell migration, while trihydrophobin 1 (TH1) inhibits MAPK/ERK activation and cell migration through interaction with A-Raf and PAK1 and inhibiting their kinase activities. Here we show that c-Src interacts with TH1 by GST-pull down assay, coimmunoprecipitation and confocal microscopy assay. The interaction leads to phosphorylation of TH1 at Tyr-6 in vivo and in vitro. Phosphorylation of TH1 decreases its association with A-Raf and PAK1. Further study reveals that Tyr-6 phosphorylation of TH1 reduces its inhibition on MAPK/ERK signaling, enhances c-Src mediated cell migration. Moreover, induced tyrosine phosphorylation of TH1 has been found by EGF and estrogen treatments. Taken together, our findings demonstrate a novel mechanism for the comprehensive regulation of Ras/Raf/MEK/ERK signaling and cell migration involving tyrosine phosphorylation of TH1 by c-Src

Treatment of advanced, recurrent, resistant to previous treatments basal and squamous cell skin carcinomas with a synergistic formulation of interferons. Open, prospective study

<p>Abstract</p> <p>Background</p> <p>Aggressive non-melanoma skin cancer (deeply infiltrating, recurrent, and morphea form lesions) are therapeutically challenging because they require considerable tissue loss and may demand radical disfiguring surgery. Interferons (IFN) may provide a non-surgical approach to the management of these tumors. The aim of this work was to evaluate the effect of a formulation containing IFNs-α and -γ in synergistic proportions on patients with recurrent, advanced basal cell (BCC) or squamous cell skin carcinomas (SCSC).</p> <p>Methods</p> <p>Patients with extensive, recurrent, resistant to other procedures BCC or SCSC received the IFN formulation peri- and intralesionally, three times per week for 3 weeks. They had been previously treated with surgery and/or radiotherapy or chemotherapy. Thirteen weeks after the end of treatment, the original lesion sites were examined for histological evidence of remaining tumor.</p> <p>Results</p> <p>Sixteen elder (median 70 years-old) patients were included. They beared 12 BCC and 4 SCSC ranging from 1.5 to 12.5 cm in the longest dimension. At the end of treatment 47% CR (complete tumor elimination), 40% PR (>30% tumor reduction), and 13% stable disease were obtained. None of the patients relapsed during the treatment period. The median duration of the response was 38 months. Only one patient with complete response had relapsed until today. Principal adverse reactions were influenza-like symptoms well known to occur with interferon therapy, which were well tolerated.</p> <p>Conclusion</p> <p>The peri- and intralesional combination of IFNs-α and -γ was safe and showed effect for the treatment of advanced, recurrent and resistant to previous treatments of BCC and SCSC in elder patients. This is the first report of such treatment in patients with advance non-melanoma skin cancer. The encouraging result justifies further confirmatory trials.</p> <p>Trial registration</p> <p>Current Controlled Trials RPCEC00000052.</p

A Quorum Sensing Regulated Small Volatile Molecule Reduces Acute Virulence and Promotes Chronic Infection Phenotypes

A significant number of environmental microorganisms can cause serious, even fatal, acute and chronic infections in humans. The severity and outcome of each type of infection depends on the expression of specific bacterial phenotypes controlled by complex regulatory networks that sense and respond to the host environment. Although bacterial signals that contribute to a successful acute infection have been identified in a number of pathogens, the signals that mediate the onset and establishment of chronic infections have yet to be discovered. We identified a volatile, low molecular weight molecule, 2-amino acetophenone (2-AA), produced by the opportunistic human pathogen Pseudomonas aeruginosa that reduces bacterial virulence in vivo in flies and in an acute mouse infection model. 2-AA modulates the activity of the virulence regulator MvfR (multiple virulence factor regulator) via a negative feedback loop and it promotes the emergence of P. aeruginosa phenotypes that likely promote chronic lung infections, including accumulation of lasR mutants, long-term survival at stationary phase, and persistence in a Drosophila infection model. We report for the first time the existence of a quorum sensing (QS) regulated volatile molecule that induces bistability phenotype by stochastically silencing acute virulence functions in P. aeruginosa. We propose that 2-AA mediates changes in a subpopulation of cells that facilitate the exploitation of dynamic host environments and promote gene expression changes that favor chronic infections

Rhizobium Promotes Non-Legumes Growth and Quality in Several Production Steps: Towards a Biofertilization of Edible Raw Vegetables Healthy for Humans

The biofertilization of crops with plant-growth-promoting microorganisms is currently considered as a healthy alternative to chemical fertilization. However, only microorganisms safe for humans can be used as biofertilizers, particularly in vegetables that are raw consumed, in order to avoid sanitary problems derived from the presence of pathogenic bacteria in the final products. In the present work we showed that Rhizobium strains colonize the roots of tomato and pepper plants promoting their growth in different production stages increasing yield and quality of seedlings and fruits. Our results confirmed those obtained in cereals and alimentary oil producing plants extending the number of non-legumes susceptible to be biofertilized with rhizobia to those whose fruits are raw consumed. This is a relevant conclusion since safety of rhizobia for human health has been demonstrated after several decades of legume inoculation ensuring that they are optimal bacteria for biofertilization

Deoxycholate induces COX-2 expression via Erk1/2-, p38-MAPK and AP-1-dependent mechanisms in esophageal cancer cells

<p>Abstract</p> <p>Background</p> <p>The progression from Barrett's metaplasia to adenocarcinoma is associated with the acquirement of an apoptosis-resistant phenotype. The bile acid deoxycholate (DCA) has been proposed to play an important role in the development of esophageal adenocarcinoma, but the precise molecular mechanisms remain undefined. The aim of this study was to investigate DCA-stimulated COX-2 signaling pathways and their possible contribution to deregulated cell survival and apoptosis in esophageal adenocarcinoma cells.</p> <p>Methods</p> <p>Following exposure of SKGT-4 cells to DCA, protein levels of COX-2, MAPK and PARP were examined by immunoblotting. AP-1 activity was assessed by mobility shift assay. DCA-induced toxicity was assessed by DNA fragmentation and MTT assay.</p> <p>Results</p> <p>DCA induced persistent activation of the AP-1 transcription factor with Fra-1 and JunB identified as the predominant components of the DCA-induced AP-1 complex. DCA activated Fra-1 via the Erk1/2- and p38 MAPK while Erk1/2 is upstream of JunB. Moreover, DCA stimulation mediated inhibition of proliferation with concomitant low levels of caspase-3-dependent PARP cleavage and DNA fragmentation. Induction of the anti-apoptotic protein COX-2 by DCA, via MAPK/AP-1 pathway appeared to balance the DCA mediated activation of pro-apoptotic markers such as PARP cleavage and DNA fragmentation. Both of these markers were increased upon COX-2 suppression by aspirin pretreatment prior to DCA exposure.</p> <p>Conclusion</p> <p>DCA regulates both apoptosis and COX-2-regulated cell survival in esophageal cells suggesting that the balance between these two opposing signals may determine the transformation potential of DCA as a component of the refluxate.</p

An overview of harms associated with β-lactam antimicrobials: where do the carbapenems fit in?

The US Institute of Medicine's focus on patient safety has motivated hospital administrators to facilitate a culture of safety. As a result, subcommittees of the pharmacy and therapeutics committee have emerged in many hospitals to focus on adverse events and patient safety. Antimicrobial harms have gained the attention of practicing clinicians and hospital formulary committees, because they top the list of drugs that are associated with adverse events and because of certain serious harms that have ultimately led to the withdrawal of some antimicrobial agents. In the near future, several antimicrobials in the late phase of development will become available for clinical use (ceftobiprole, ceftaroline, and telavancin), and others (doripenem and dalbavancin) have recently joined the armamentarium. Because new antimicrobials will become part of the treatment armamentarium, it is important to discuss our current understanding of antimicrobial harms in general. Although not thought of as traditional adverse events, Clostridium difficile infection and development of resistance during therapy are adverse events that occur as a result of antimicrobial exposure and therefore are discussed. In addition, a distillation of our current understanding of β-lactam specific adverse events will be provided. Finally, new methods of administration are being evaluated that may influence peak concentration-related antimicrobial adverse events

Neglected Tropical Diseases in Sub-Saharan Africa: Review of Their Prevalence, Distribution, and Disease Burden

The neglected tropical diseases (NTDs) are the most common conditions affecting the poorest 500 million people living in sub-Saharan Africa (SSA), and together produce a burden of disease that may be equivalent to up to one-half of SSA's malaria disease burden and more than double that caused by tuberculosis. Approximately 85% of the NTD disease burden results from helminth infections. Hookworm infection occurs in almost half of SSA's poorest people, including 40–50 million school-aged children and 7 million pregnant women in whom it is a leading cause of anemia. Schistosomiasis is the second most prevalent NTD after hookworm (192 million cases), accounting for 93% of the world's number of cases and possibly associated with increased horizontal transmission of HIV/AIDS. Lymphatic filariasis (46–51 million cases) and onchocerciasis (37 million cases) are also widespread in SSA, each disease representing a significant cause of disability and reduction in the region's agricultural productivity. There is a dearth of information on Africa's non-helminth NTDs. The protozoan infections, human African trypanosomiasis and visceral leishmaniasis, affect almost 100,000 people, primarily in areas of conflict in SSA where they cause high mortality, and where trachoma is the most prevalent bacterial NTD (30 million cases). However, there are little or no data on some very important protozoan infections, e.g., amebiasis and toxoplasmosis; bacterial infections, e.g., typhoid fever and non-typhoidal salmonellosis, the tick-borne bacterial zoonoses, and non-tuberculosis mycobaterial infections; and arboviral infections. Thus, the overall burden of Africa's NTDs may be severely underestimated. A full assessment is an important step for disease control priorities, particularly in Nigeria and the Democratic Republic of Congo, where the greatest number of NTDs may occur