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The association of early‐onset non‐progressive ataxia and miosis is an extremely rare phenotypic entity occasionally reported in the literature. To date, only one family (two siblings and their mother) has benefited from a genetic diagnosis by the identification of a missense heterozygous variant (p.Arg36Cys) in the ITPR1 gene. This gene encodes the inositol 1,4,5‐trisphosphate receptor type 1, an intracellular channel that mediates calcium release from the endoplasmic reticulum. Deleterious variants in this gene are known to be associated with two types of spinocerebellar ataxia, SCA15 and SCA29, and with Gillespie syndrome that is associated with ataxia, partial iris hypoplasia, and intellectual disability. In this work, we describe a novel individual carrying a heterozygous missense variant (p.Arg36Pro) at the same position in the N‐terminal suppressor domain of ITPR1 as the family previously reported, with the same phenotype associating early‐onset non‐progressive ataxia and miosis. This second report confirms the implication of ITPR1 in the miosis–ataxia syndrome and therefore broadens the clinical spectrum of the gene. Moreover, the high specificity of the phenotype makes it a recognizable syndrome of genetic origin. [ABSTRACT FROM AUTHOR]

Background: Multislice spiral computed tomography (MSCT) requires an interpolation between adjacent detector rows during backprojection. Not satisfying the Nyquist sampling condition along the z‐axis results in aliasing effects, also known as windmill artifacts. These image distortions are characterized by bright streaks diverging from high contrast structures. Purpose: The z‐flying focal spot (zFFS) is a well‐established hardware‐based solution that aims to double the sampling rate in longitudinal direction and therefore reduce aliasing artifacts. However, given the technical complexity of the zFFS, this work proposes a deep learning‐based approach as an alternative solution. Methods: We propose a supervised learning approach to perform a mapping between input projections and the corresponding rows required for double sampling in the z‐direction. We present a comprehensive evaluation using both a clinical dataset obtained using raw data from 40 real patient scans acquired with zFFS and a synthetic dataset consisting of 100 simulated spiral scans using a phantom specifically designed for our problem. For the clinical dataset, we utilized 32 scans as training set and 8 scans as validation set, whereas for the synthetic dataset, we used 80 scans for training and 20 scans for validation purposes. Both qualitative and quantitative assessments are conducted on a test set consisting of nine real patient scans and six phantom measurements to validate the performance of our approach. A simulation study was performed to investigate the robustness against different scan configurations in terms of detector collimation and pitch value. Results: In the quantitative comparison based on clinical patient scans from the test set, all network configurations show an improvement in the root mean square error (RMSE) of approximately 20% compared to neglecting the doubled longitudinal sampling by the zFFS. The results of the qualitative analysis indicate that both clinical and synthetic training data can reduce windmill artifacts through the application of a correspondingly trained network. Together with the qualitative results from the test set phantom measurements it is emphasized that a training of our method with synthetic data resulted in superior performance in windmill artifact reduction. Conclusions: Deep learning‐based raw data interpolation has the potential to enhance the sampling in z‐direction and thus minimize aliasing effects, as it is the case with the zFFS. Especially a training with synthetic data showed promising results. While it may not outperform zFFS, our method represents a beneficial solution for CT scanners lacking the necessary hardware components for zFFS. [ABSTRACT FROM AUTHOR]

Background: Due to technical constraints, dual‐source dual‐energy CT scans may lack spectral information in the periphery of the patient. Purpose: Here, we propose a deep learning‐based iterative reconstruction to recover the missing spectral information outside the field of measurement (FOM) of the second source‐detector pair. Methods: In today's Siemens dual‐source CT systems, one source‐detector pair (referred to as A) typically has a FOM of about 50 cm, while the FOM of the other pair (referred to as B) is limited by technical constraints to a diameter of about 35 cm. As a result, dual‐energy applications are currently only available within the small FOM, limiting their use for larger patients. To derive a reconstruction at B's energy for the entire patient cross‐section, we propose a deep learning‐based iterative reconstruction. Starting with A's reconstruction as initial estimate, it employs a neural network in each iteration to refine the current estimate according to a raw data fidelity measure. Here, the corresponding mapping is trained using simulated chest, abdomen, and pelvis scans based on a data set containing 70 full body CT scans. Finally, the proposed approach is tested on simulated and measured dual‐source dual‐energy scans and compared against existing reference approaches. Results: For all test cases, the proposed approach was able to provide artifact‐free CT reconstructions of B for the entire patient cross‐section. Considering simulated data, the remaining error of the reconstructions is between 10 and 17 HU on average, which is about half as low as the reference approaches. A similar performance with an average error of 8 HU could be achieved for real phantom measurements. Conclusions: The proposed approach is able to recover missing dual‐energy information for patients exceeding the small 35 cm FOM of dual‐source CT systems. Therefore, it potentially allows to extend dual‐energy applications to the entire‐patient cross section. [ABSTRACT FROM AUTHOR]

Most Chinese provinces have a daily‐updated database of live animal movements; however, the data are not efficiently utilized to support interventions to control H7N9 and other avian influenzas. Based on official records, this study assessed the spatio‐temporal patterns of live broilers moved out of and within Guangxi in 2017. The yearly and monthly networks were analyzed for inter‐ and intra‐provincial movements, respectively. Approximately 200,000 movements occurred in 2017, involving the transport of 200 million live broilers from Guangxi. Although Guangxi exported to 24 out of 32 provinces of China, 95% of inter‐provincial movements occurred with three bordering provinces. Within Guangxi, counties were highly connected through the live broiler movements, creating conditions for rapid virus spreading throughout the province. Interestingly, a peak in movements during the Chinese Lunar New Year celebrations, late January in 2017, was not observed in this study, likely due to H7N9‐related control measures constraining live bird trading. Both intra‐ and inter‐provincial movements in March 2017 were significantly higher than in other months of that year, suggesting that dramatic price changes may influence the movement's network and reshape the risk pathways. However, despite these variations, the same small proportion of counties (less than 20%) exporting/importing more than 90% of inter‐ and intra‐provincial movements remains the same throughout the year. Interventions, particularly surveillance and improving biosecurity, targeted to those counties are thus likely to be more effective for avian influenza risk mitigation than implemented indiscriminately. Additionally, simulations further demonstrated that targeting counties according to their degree or betweenness in the movement network would be the most efficient way to limit disease transmission via broiler movements. The study findings provide evidence to support the design of risk‐based control interventions for H7N9 and all other avian influenza viruses in broiler value chains in Guangxi. [ABSTRACT FROM AUTHOR]

Purpose: A motion compensation method that is aimed at correcting motion artifacts of cardiac valves is proposed. The primary focus is the aortic valve. Methods: The method is based around partial angle reconstructions and a cost function including the image entropy. A motion model is applied to approximate the cardiac motion in the temporal and spatial domain. Based on characteristic values for velocities and strain during cardiac motion, penalties for the velocity and spatial derivatives are introduced to maintain anatomically realistic motion vector fields and avoid distortions. The model addresses global elastic deformation, but not the finer and more complicated motion of the valve leaflets. Results: The method is verified based on clinical data. Image quality was improved for most artifact‐impaired reconstructions. An image quality study with Likert scoring of the motion artifact severity on a scale from 1 (highest image quality) to 5 (lowest image quality/extreme artifact presence) was performed. The biggest improvements after applying motion compensation were achieved for strongly artifact‐impaired initial images scoring 4 and 5, resulting in an average change of the scores by −0.59±0.06$-0.59\pm 0.06$ and −1.33±0.03$-1.33\pm 0.03$, respectively. In the case of artifact‐free images, a chance to introduce blurring was observed and their average score was raised by 0.42 ± 0.03. Conclusion: Motion artifacts were consistently removed and image quality improved. [ABSTRACT FROM AUTHOR]

Purpose: Dual‐source computed tomography (DSCT) uses two source‐detector pairs offset by about 90°. In addition to the well‐known forward scatter, a special issue in DSCT is cross‐scattered radiation from X‐ray tube A detected in the detector of system B and vice versa. This effect can lead to artifacts and reduction of the contrast‐to‐noise ratio of the images. The purpose of this work is to present and evaluate different deep learning‐based methods for scatter correction in DSCT. Methods: We present different neural network‐based methods for forward and cross‐scatter correction in DSCT. These deep scatter estimation (DSE) methods mainly differ in the input and output information that is provided for training and inference and in whether they operate on two‐dimensional (2D) or on three‐dimensional (3D) data. The networks are trained and validated with scatter distributions obtained by our in‐house Monte Carlo simulation. The simulated geometry is adapted to a realistic clinical setup. Results: All DSE approaches reduce scatter‐induced artifacts and lead to superior results than the measurement‐based scatter correction. Forward scatter, under the presence of cross‐scatter, is best estimated either by our network that uses the current projection and a couple of neighboring views (fDSE 2D few views) or by our 3D network that processes all projections simultaneously (fDSE 3D). Cross‐scatter, under the presence of forward scatter, is best estimated using xSSE XDSE 2D, with xSSE referring to a quick single scatter estimate of cross scatter, or by xDSE 3D that uses all projections simultaneously. By using our proposed networks, the total scatter error in dual could be reduced from about 18 HU to approximately 3 HU. Conclusions: Deep learning‐based scatter correction can reduce scatter artifacts in DSCT. To achieve more accurate cross‐scatter estimations, the use of a cross‐scatter approximation improves the results. Also, the ability to leverage across different projection angles improves the precision of the algorithm. [ABSTRACT FROM AUTHOR]

Purpose: During a typical cardiac short scan, the heart can move several millimeters. As a result, the corresponding CT reconstructions may be corrupted by motion artifacts. Especially the assessment of small structures, such as the coronary arteries, is potentially impaired by the presence of these artifacts. In order to estimate and compensate for coronary artery motion, this manuscript proposes the deep partial angle‐based motion compensation (Deep PAMoCo). Methods: The basic principle of the Deep PAMoCo relies on the concept of partial angle reconstructions (PARs), that is, it divides the short scan data into several consecutive angular segments and reconstructs them separately. Subsequently, the PARs are deformed according to a motion vector field (MVF) such that they represent the same motion state and summed up to obtain the final motion‐compensated reconstruction. However, in contrast to prior work that is based on the same principle, the Deep PAMoCo estimates and applies the MVF via a deep neural network to increase the computational performance as well as the quality of the motion compensated reconstructions. Results: Using simulated data, it could be demonstrated that the Deep PAMoCo is able to remove almost all motion artifacts independent of the contrast, the radius and the motion amplitude of the coronary artery. In any case, the average error of the CT values along the coronary artery is about 25 HU while errors of up to 300 HU can be observed if no correction is applied. Similar results were obtained for clinical cardiac CT scans where the Deep PAMoCo clearly outperforms state‐of‐the‐art coronary artery motion compensation approaches in terms of processing time as well as accuracy. Conclusions: The Deep PAMoCo provides an efficient approach to increase the diagnostic value of cardiac CT scans even if they are highly corrupted by motion. [ABSTRACT FROM AUTHOR]

The ongoing circulation of Highly Pathogenic Avian Influenza (HPAI) H5N1 poses a threat to both poultry and public health. Adapting the constructs of the Health Belief Model (HBM) framework, we investigated perceptions of backyard, commercial broiler and layer chicken farmers to implement HPAI prevention and control measures in Bangladesh. Two cross‐sectional studies were conducted in 2016 and 2017 on 144 backyard, 106 broiler and 113 layer chicken farms. Using Structural Equation Modelling, we modelled the direct and indirect effects on farmers' perceptions on taking HPAI prevention and control actions. Our results indicate that farmers of different chicken production systems have different decision‐making processes. While perceived barriers to the implementation of prevention and control measures (e.g. wearing protective equipment when handling chickens) prevented both broiler and backyard farmers to adopt interventions, perceived benefits of measures (e.g. maintaining high biosecurity will reduce the risk of birds becoming sick) strongly influenced commercial farmers' decisions, but not backyard farmers' decisions. Information provided on HPAI through media, meetings or via information campaigns played an important role in farmers' decision‐making in all production systems. Outcomes of this research can be used to tailor advice on HPAI control and prevention to different poultry farming groups by accounting for specific factors influencing their decision‐making, instead of using one‐size‐fit‐all communication approach. [ABSTRACT FROM AUTHOR]

Background: Dupilumab is approved for use in moderate‐to‐severe atopic dermatitis (AD) and as an add‐on maintenance treatment in patients suffering from severe asthma with type 2 inflammation. Ocular adverse events (OAEs) have been reported with dupilumab almost exclusively in patients treated for AD. Objectives: The objectives of this study were to describe the incidence and nature of dupilumab‐induced OAEs and to assess the potential predisposing factors. Patients and methods: We conducted a prospective, single‐centre, real‐life study in adult AD patients treated with dupilumab, who were systematically examined by an ophthalmologist before and during treatment. Results: Forty‐six patients were included prospectively with a median age of 41.1 years and a median initial SCOring Atopic Dermatitis of 46.0 (IQR: 34.5–55.5). OAEs concerned 34.8% of patients and were mostly of mild to moderate severity. Two patients had to discontinue treatment due to OAE. The majority of patients developed or aggravated dry eye disease, with superficial punctate keratitis (SPK). Six patients developed conjunctivitis. Dupilumab‐induced OAEs were associated with the following pre‐existing parameters: dry eye disease with SPK (Odds ratio (OR); 6.3 [95% confidence interval (CI): 1.3–31.6]), eyelid eczema (OR: 8.7 [95%CI: 1.8–40.6]), history of food allergy (OR 3.8 (95% CI: 1.002–14,070) and IgE serum level> 1000 kU/L (OR:10.6 [CI 95%: 1.2–91.3]). Conclusion: Atopic dermatitis patients with eyelid eczema or dry eye disease symptoms may be referred to an ophthalmologist before starting dupilumab to consider initiating preventive eye hydration measures. Further multicentric and translational studies are warranted to better explain OAEs pathophysiology. [ABSTRACT FROM AUTHOR]

In order to control Highly Pathogenic Avian Influenza (HPAI) H5N1 and Low Pathogenic Avian Influenza (LPAI) H9N2 virus spread in endemically infected countries, a detailed understanding of infection patterns is required. We conducted cross‐sectional studies in Bangladesh in 2016 and 2017, on 144 backyard, 106 broiler and 113 layer chicken farms. Although all sampled birds were negative for H5 virus by RT‐PCR, H5 antibodies were detected in unvaccinated birds on all three farming systems. Higher H5 antibody prevalence was observed in ducks raised on backyard farms, 14.2% (95% CI: 10.0%–19.8%), compared to in‐contact backyard chickens, 4.2% (95% CI: 2.8%–6.1%). The H5 antibody prevalence was lower in broiler chickens, 1.5% (95% CI: 0.9%–2.5%), compared to layer chickens, 7.8% (95% CI: 6.1%–9.8%). H9 viruses were detected by RT‐PCR in 0.5% (95% CI: 0.2%–1.3%) and 0.6% (95% CI: 0.3%–1.5%) of broilers and layers, respectively, and in 0.2% (95% CI: 0.0%–1.2%) of backyard chickens. Backyard chickens and ducks showed similar H9 antibody prevalence, 16.0% (95% CI: 13.2%–19.2%) and 15.7% (95% CI: 11.3%–21.4%), which was higher compared to layers, 5.8% (95% CI: 4.3%–7.6%), and broilers, 1.5% (95% CI: 0.9%–2.5%). Over the course of a production cycle, H5 and H9 antibody prevalence increased with the age of backyard and layer chickens. Usually, multiple ducks within a flock were H5 antibody positive, in contrast to backyard chickens, broilers and layers where only individual birds within flocks developed H5 antibodies. Our findings highlight low virus circulation in healthy chickens of all production systems in Bangladesh, which is in contrast to high virus circulation reported from live bird markets. Data generated in this project can be used to adopt risk‐based surveillance approaches in different chicken production systems in Bangladesh and to inform mathematical models exploring HPAI infection dynamics in poultry from the source of production. [ABSTRACT FROM AUTHOR]

Cytomegalovirus (CMV) infection is responsible for significant morbidity and mortality in immunocompromised patients, namely solid organ and hematopoietic cell transplant recipients, and can induce congenital infection in neonates. There is currently an unmet need for new management and treatment strategies. Establishment of an anti‐CMV immune response is critical in order to control CMV infection. The two main human T cells involved in HCMV‐specific response are αβ and non‐Vγ9Vδ2 T cells that belong to γδ T cell compartment. CMV‐induced non‐Vγ9Vδ2 T cells harbor a specific clonal expansion and a phenotypic signature, and display effector functions against CMV. So far, only two main molecular mechanisms underlying CMV sensing have been identified. Non‐Vγ9Vδ2 T cells can be activated either by stress‐induced surface expression of the γδT cell receptor (TCR) ligand annexin A2, or by a multimolecular stress signature composed of the γδTCR ligand endothelial protein C receptor and co‐stimulatory signals such as the ICAM‐1‐LFA‐1 axis. All this basic knowledge can be harnessed to improve the clinical management of CMV infection in at‐risk patients. In particular, non‐Vγ9Vδ2 T cell monitoring could help better stratify the risk of infection and move forward a personalized medicine. Moreover, recent advances in cell therapy protocols open the way for a non‐Vγ9Vδ2 T cell therapy in immunocompromised patients. [ABSTRACT FROM AUTHOR]

Today, brucellosis is the most common global bacterial zoonosis, bringing with it a range of significant health and economic consequences, yet it is rarely identified from the archaeological record. Detection and understanding of past zoonoses could be improved by triangulating evidence and proxies generated through different approaches. The complex socioecological systems that support zoonoses involve humans, animals, and pathogens interacting within specific environmental and cultural contexts, and as such, there is a diversity of potential datasets that can be targeted. To capture this, in this paper, we consider how to approach the study of zoonotic brucellosis in the past from a One Health perspective, one which explicitly acknowledges the health link between people, animals, and environments (both physical and cultural). One Health research is explicitly interdisciplinary and conceptually moves away from an anthropocentric approach, allowing the component parts to be considered in holistic and integrated ways to deliver more comprehensive understanding. To this end, in this paper, we review the methods, selected evidence, and potential for past brucellosis identification and understanding, focussing on osteological markers in humans and animals, historical, biomolecular, and epidemiological approaches. We also present an agenda and potential for future research. [ABSTRACT FROM AUTHOR]

Relapsed/refractory B-cell NHLs are made up with a heterogeneous array of incurable diseases, whose outcomes in the rituximab era are unclear, despite patients benefit from new therapeutic strategies. Here, we present a new preclinical follicular lymphoma (FL) 3D model called Patient-Derived Lymphoma Spheroid (FL-PDLS) that recapitulates the FL pathogenesis and the B cells-immune tumor microenvironment crosstalk. This system can evolve towards full FL-TME reconstituted organoids and therefore become powerful theragnostic biomaterials that combine therapy with diagnosis necessary for individualized therapies for patients. [Extracted from the article]

From several years, the anticancer effects of Vγ9 T lymphocytes make these cells good candidates for cancer immunotherapies. However, the proved efficacy of γδ Τ cell-based cancer immunotherapies in some clinical trials was minimized due to the inherent toxicity of IL-2, which is essential for the combination therapy with Phosphoantigen (PAg). Recently, we showed that IL-33, a γ chain receptor-independent cytokine, was able to induce the in vitro proliferation of PAg-activated Vγ9 T cells, which were fully functional expressing IFN-γ and TNF-α and showing in vitro anti-tumor cytotoxicity. We proposed IL-33 as an alternative to IL-2 for Vγ9 T cell-based cancer immunotherapies, and have therefore evaluated the efficacy of this cytokine in preclinical investigations. This study shows that human Vγ9 T cells are able to proliferate in a mouse model with the combination of PAg and rhIL-33, and that IL-33-expanded Vγ9 T cells can prevent tumor growth in a mouse lymphoma model. [ABSTRACT FROM AUTHOR]

Effectiveness of current passive zoonotic disease surveillance systems is limited by the under-reporting of disease outbreaks in the domestic animal population. Evaluating the acceptability of passive surveillance and its economic, social and cultural determinants appears a critical step for improving it. A participatory rural appraisal was implemented in a rural subdistrict of Thailand. Focus group interviews were used to identify sanitary risks perceived by native chicken farmers and describe the structure of their value chain. Qualitative individual interviews with a large diversity of actors enabled to identify perceived costs and benefits associated with the reporting of HPAI suspicions to sanitary authorities. Besides, flows of information on HPAI suspected cases were assessed using network analysis, based on data collected through individual questionnaires. Results show that the presence of cockfighting activities in the area negatively affected the willingness of all chicken farmers and other actors to report suspected HPAI cases. The high financial and affective value of fighting cocks contradicted the HPAI control policy based on mass culling. However, the importance of product quality in the native chicken meat value chain and the free veterinary services and products delivered by veterinary officers had a positive impact on suspected case reporting. Besides, cockfighting practitioners had a significantly higher centrality than other actors in the information network and they facilitated the spatial diffusion of information. Social ties built in cockfighting activities and the shared purpose of protecting valuable cocks were at the basis of the diffusion of information and the informal collective management of diseases. Building bridges with this informal network would greatly improve the effectiveness of passive surveillance. [ABSTRACT FROM AUTHOR]

Human blood γδ T lymphocytes express TCRVγ9Vδ2 and respond to nonpeptide phosphoantigens (PAgs) by a mysterious mechanism involving the BTN3A1 (CD277) molecule . BTN3A1 is a butyrophilin-like protein related to CD80, PD-L1, and MHC, and is either a presenting or a co-stimulatory molecule for PAgs. Although the precise roles and molecular interactions with the TCRVγ9Vδ2 are currently not determined, it is commonly thought that all TCRVγ9Vδ2 lymphocytes 'see' PAg and BTN3A1 together, presumably in a single molecular recognition event. But whether this recognition event could be reproduced in a simplified model was not addressed in previous studies. In this issue, Starick et al. ( Eur. J. Immunol. 2017. 47: 982-992) compared the response of three TCRVγ9Vδ2 pairs of murine and human cell transfectants to PAg and anti-BTN3A1 antibodies using IL-2 release as a readout. The authors found that although the two murine transfectants responded similarly to either stimuli, one murine TCRVγ9Vδ2 transfectant reacted to PAgs but not to anti-BTN3A1 (mAb 20.1). Human transductants behave in a similar fashion, demonstrating that TCRVγ9Vδ2 lymphocytes differentiate PAg and BTN3A1 signals, while species of the transductants unmask this differential sensitivity. Indeed, understanding the puzzling mode of antigen recognition by γδ T lymphocytes will be essential for developing γδ T-cell-based immunotherapies, and the authors of this study now demonstrate that TCRVγ9Vδ2 lymphocytes are able to differentiate the PAg and BTN3A1 stimuli. [ABSTRACT FROM AUTHOR]

While swine production is rapidly growing in South- East Asia, the structure of the swine industry and the dynamic of pig movements have not been well-studied. However, this knowledge is a prerequisite for understanding the dynamic of disease transmission in swine populations and designing cost-effective surveillance strategies for infectious diseases. In this study, we assessed the farming and trading practices in the Vietnamese swine familial farming sector, which accounts for most pigs in Vietnam, and for which disease surveillance is a major challenge. Farmers from two communes of a Red River Delta Province (northern Vietnam) were interviewed, along with traders involved in pig transactions. Major differences in the trade structure were observed between the two communes. One commune had mainly transversal trades, that is between farms of equivalent sizes, whereas the other had pyramidal trades, that is from larger to smaller farms. Companies and large familial farrow-to-finish farms were likely to act as major sources of disease spread through pig sales, demonstrating their importance for disease control. Familial fattening farms with high pig purchases were at greater risk of disease introduction and should be targeted for disease detection as part of a risk-based surveillance. In contrast, many other familial farms were isolated or weakly connected to the swine trade network limiting their relevance for surveillance activities. However, some of these farms used boar hiring for breeding, increasing the risk of disease spread. Most familial farms were slaughtering pigs at the farm or in small local slaughterhouses, making the surveillance at the slaughterhouse inefficient. In terms of spatial distribution of the trades, the results suggested that northern provinces were highly connected and showed some connection with central and southern provinces. These results are useful to develop risk-based surveillance protocols for disease detection in the swine familial sector and to make recommendations for disease control. [ABSTRACT FROM AUTHOR]

Cyclic dinucleotides, a class of microbial messengers, have been recently identified in bacteria, but their activity in humans remains largely unknown. Here, we have studied the function of cyclic dinucleotides in humans. We found that c-di-AMP and cGAMP, two adenosine-based cyclic dinucleotides, activated T lymphocytes in an unusual manner through monocyte cell death. c-di-AMP and cGAMP induced the selective apoptosis of human monocytes, and T lymphocytes were activated by the direct contact with these dying monocytes. The ensuing T-cell response comprised cell-cycle exit, phenotypic maturation into effector memory cells and proliferation arrest, but not cell death. This quiescence was transient since T cells remained fully responsive to further restimulation. Together, our results depict a novel activation pattern for human T lymphocytes: a transient quiescence induced by c-di-AMP- or cGAMP-primed apoptotic monocytes. [ABSTRACT FROM AUTHOR]

Purpose: We have previously shown that 9′‐cis‐norbixin (norbixin) protects retinal pigmented epithelium (RPE) cells against phototoxicity induced by blue light and N‐retinylidene‐N‐retinylethanolamine (A2E) in vitro and preserves visual function in animal models of dry Age‐related Macular Degeneration (AMD) in vivo. The purpose of this study was to examine the mode of action and the in vitro and in vivo effects of CN30, a norbixin monoamide conjugate. Methods: Ocular pharmacokinetics in rats administered orally with 50 mg/kg of norbixin, or its conjugate (CN30) were compared. Their effect on photoprotection of primary porcine RPE cells challenged with A2E and blue‐light illumination was quantified. The effects of CN30 on the A2E‐induced transactivation of PPARs, AP‐1 and NF‐κB were measured by reporter gene luciferase activity. The expression of IL‐6, IL‐8, and VEGF was measured by RT‐QPCR. The in vivo neuroprotective effect of intraperitoneally administered CN30 was evaluated by measuring retinal thickness and electroretinogram (ERG) amplitudes in a blue‐light damage (BLD) acute model in albino rats. CN30 efficacy was also assessed by ERG after 6 months oral supplementation in Abca4−/−Rdh8−/− mice. Results: Compared to norbixin, CN30 displays improved stability and enhanced ocular maximal concentration and exposure (AUC). Similar to our previous observation with norbixin, CN30 mode of action involves the inhibition of PPARs, NF‐κB and AP‐1 transactivation. CN30 reduces IL‐6, IL‐8 and VEGF expression induced by A2E in vitro. In vivo, CN30 protects visual function and retinal structure in albino rats subjected to BLD in an acute model of retinal degeneration. Moreover, 6 months oral supplementation also improve visual function in a model of dry AMD: the Abca4−/−Rdh8−/− double knock‐out mice. Conclusions: CN30 retains the protective properties of norbixin in vitro and in vivo, and displays improved stability and pharmacokinetic properties. This could open new avenues for the oral treatment of retinal degenerative diseases such as dry AMD. [ABSTRACT FROM AUTHOR]

The peripheral endogenous opioid system is critically involved in neuropathic and inflammatory pain generation as suggested by the modulation of opioid receptors expression and enkephalins (ENKs) release observed in these painful conditions. Accordingly, an innovative approach in the treatment of these nocifensive events is to increase and maintain high local concentrations of extracellular pain-evoked ENKs, by preventing their physiological enzymatic inactivation by two Zn metallopeptidases, the neutral endopeptidase (NEP, neprilysin, EC 3.4.24.11) and the neutral aminopeptidase (APN, EC 3.4.11.2). With this aim, new orally active dual ENKephalinase inhibitors (DENKIs) were designed as soluble prodrugs by introducing a N-terminal cleavable carbamate in the previously described aminophosphinic inhibitors. This induces long-lasting antinociceptive responses after oral administration, in various rodent models of inflammatory and neuropathic pain. These responses are mediated through stimulation of peripheral opioid receptors by DENKIs-protected ENKs as demonstrated by naloxone methiodide reversion. In all tested models, the most efficient prodrug 2a (PL265) was active, at least during 150-180 min, after single oral administration of 25-50 mg/kg in mice and of 100-200 mg/kg in rats. In models of neuropathic pain, both hyperalgesia and allodynia were markedly reduced. Interestingly, combination of inactive doses of 2a (PL265) and of the anti-epileptic drug gabapentin had synergistic effect on neuropathic pain. Pharmacokinetic studies of 2a (PL265) in rats show that the active drug is the only generated metabolite produced. These encouraging results have made 2a (PL265) a suitable candidate for clinical development. [ABSTRACT FROM AUTHOR]

SUMMARY In the present work, we propose to extend to the Stokes problem a fictitious domain approach inspired by extended finite element method and studied for the Poisson problem in a paper of Renard and Haslinger of 2009. The method allows computations in domains whose boundaries do not match. A mixed FEM is used for the fluid flow. The interface between the fluid and the structure is localized by a level-set function. Dirichlet boundary conditions are taken into account using Lagrange multiplier. A stabilization term is introduced to improve the approximation of the normal trace of the Cauchy stress tensor at the interface and avoid the inf-sup condition between the spaces for the velocity and the Lagrange multiplier. Convergence analysis is given, and several numerical tests are performed to illustrate the capabilities of the method. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background and Purpose Follicular lymphoma is the second most common non- Hodgkin's lymphoma and, despite the introduction of rituximab for its treatment, this disease is still considered incurable. Besides genetic alterations involving Bcl-2, Bcl-6 or c- Myc, follicular lymphoma cells often display altered B-cell receptor signalling pathways including overactive PKC and PI3K/Akt systems. Experimental Approach The effect of enzastaurin, an inhibitor of PKC, was evaluated both in vitro on follicular lymphoma cell lines and in vivo on a xenograft murine model. Using pharmacological inhibitors and siRNA transfection, we determined the different signalling pathways after enzastaurin treatment. Key Results Enzastaurin inhibited the serine-threonine kinase p90RSK which has downstream effects on GSK3β. Bad and p70S6K. These signalling proteins control follicular lymphoma cell survival and apoptosis; which accounted for the inhibition by enzastaurin of cell survival and its induction of apoptosis of follicular lymphoma cell lines in vitro. Importantly, these results were replicated in vivo where enzastaurin inhibited the growth of follicular lymphoma xenografts in mice. Conclusions and Implications The targeting of p90RSK by enzastaurin represents a new therapeutic option for the treatment of follicular lymphoma. [ABSTRACT FROM AUTHOR]

Global transcriptional technologies have revolutionised the study of lymphoid cell populations, but human γδ T lymphocytes specific for phosphoantigens remain far less deeply characterised by these methods despite the great therapeutic potential of these cells. Here we analyse the transcriptome of circulating TCRVγ+ γδ T cells isolated from healthy individuals, and their relation with those from other lymphoid cell subsets. We report that the gene signature of phosphoantigen-specific TCRVγ+ γδ T cells is a hybrid of those from αβ T and NK cells, with more 'NK-cell' genes than αβ T cells have and more 'T-cell' genes than NK cells. The expression profile of TCRVγ+ γδ T cells stimulated with phosphoantigen recapitulates their immediate physiological functions: Th1 cytokine, chemokine and cytotoxic activities reflect their high mitotic activity at later time points and do not indicate antigen-presenting functions. Finally, such hallmarks make the transcriptome of γδ T cells, whether resting or clonally expanding, clearly distinctive from that of NK/T or peripheral T-cell lymphomas of the γδ subtype. [ABSTRACT FROM AUTHOR]

Background Specific sunscreens against ultraviolet ( UV) A and B radiations are essential to prevent matrix degradation and the activation of intracellular signaling pathways involved in photoaging and photocarcinogenesis. Matrix degradation results from UVA-induced production of matrix metalloproteinases ( MMP) and activation of intracellular pathways in fibroblasts and keratinocytes. In particular, in keratinocytes, UVA radiation induces β-catenin nuclear translocation and stimulates MMP gene transcription. Our study was aimed at assessing the efficacy of a specific broad-spectrum sunscreen in preventing β-catenin translocation and MMPs enhanced expression in cultured keratinocytes after UVA irradiation. Methods Sunscreen or the vehicle was spread on quartz sheet. Irradiation of HaCaT cells with 6 J/cm2 UVA was performed through the sheet, and cells were collected for β-catenin immunostaining then visualization by confocal microscopy, and quantitative real-time polymerase chain reaction analysis of MMP-1, -3 and -9 gene expression. Results As shown by immunostaining and confocal microscopy, the sunscreen abrogated UVA-induced beta-catenin translocation to the nucleus, in comparison with control groups. MMP-1, -3 and -9 mRNA expression was enhanced by 7, 7 and 4 folds ( P < 0.0001, P < 0.001 and P < 0.01, respectively) in unprotected UVA-irradiated cells compared to the non-irradiated control. Sunscreen protection of the cells significantly reduced UVA-induced expression of MMP-1, -3 and -9 by 83% ( P < 0.01), 80% ( P < 0.01) and 65% ( P < 0.05), respectively. Conclusion This study demonstrated the efficacy of this broad-spectrum sunscreen in preventing UVA-induced effects on the markers of photoaging and photocarcinogenesis in vitro. It was able to protect HaCaT keratinocytes from UVA-induced β-catenin translocation to the nucleus and MMPs expression. [ABSTRACT FROM AUTHOR]

Abstract: Leukotriene A4 hydrolase (LTA4H) is a key enzyme in the inflammatory process of mammals. It is an epoxide hydrolase and an aminopeptidase of the M1 family of the MA clan of Zn-metallopeptidases. We have solved the crystal structure of LTA4H in complex with N-[3(R)-[(hydroxyamino)carbonyl]-2-benzyl-1-oxopropyl]-L-alanine, a potent inhibitor of several Zn-metalloenzymes, both endopeptidases and aminopeptidases. The inhibitor binds along the sequence signature for M1 aminopeptidases, GXMEN. It exhibits bidentate chelation of the catalytic zinc and binds to LTA4H’s enzymatically essential carboxylate recognition site. The structure gives clues to the binding of this inhibitor to related enzymes and thereby identifies residues of their S1′ sub sites as well as strategies for design of inhibitors. [ABSTRACT FROM AUTHOR]

Aminopeptidase N (APN; EC 3.4.11.2) purified from Escherichia coli has been crystallized with the optically pure aminophosphinic inhibitor PL250, H3N+-CH(CH3)-P(O)(OH)-CH2-CH(CH2Ph)-CONH-CH(CH2Ph)CO2-, which mimics the transition state of the hydrolysis reaction. PL250 inhibits APN with a Ki of 1.5-2.2 nM and its three-dimensional structure in complex with E. coli APN showed its interaction with the S1, S'1 and S'2 subsites of the catalytic site. In this structure, the Zn ion was shown to be pentacoordinated by His297, His301 and Glu320 of APN and the two O atoms of the phosphinic moiety of PL250. One of these O atoms is also involved in a hydrogen bond to Tyr381, supporting the proposed role of this amino acid in the stabilization of the transition state of the enzymatic process. The strength of the phosphinic zinc binding and the occupancy of the S'2 subsite account for the 100-fold increase in affinity of PL250 compared with the dipeptide-derived inhibitor bestatin (Ki = 4.1 x 10-6 M). Accordingly, the removal of the C-terminal phenylalanine of PL250 resulted in a large decrease in affinity (Ki = 2.17 x 10-7 M). Furthermore, it was observed that the C-terminal carboxyl group of the inhibitor makes no direct interactions with the amino acids of the APN active site. Interestingly, PL250 exhibits the same inhibitory potency for E. coli APN and for mammalian enzymes, suggesting that the structure of the complex could be used as a template for the rational design of various human APN inhibitors needed to study the role of this aminopeptidase in various pathologies. [ABSTRACT FROM AUTHOR]

Several lines of data previously indicated that N-terminally truncated forms of amyloid-β (Aβ) peptides are likely the earliest and more abundant species immunohistochemically detectable in Alzheimer’s disease-affected brains. It is noteworthy that the free N-terminal residue of full-length Aβ (fl-Aβ) is an aspartyl residue, suggesting that Aβ could be susceptible to exopeptidasic attack by aminopeptidase A (APA)-like proteases. In this context, we have examined whether APA could target Aβ peptides in both cell-free and cellular models. We first show that the general aminopeptidase inhibitor amastatin as well as two distinct aminopeptidase A inhibitors EC33 and pl302 both significantly increase the recovery of genuine fl-Aβ peptides generated by cells over-expressing Swedish-mutated β amyloid precursor protein (APP) while the aminopeptidase N blocker pl250 did not modify fl-Aβ recovery. In agreement with this observation, we establish that over-expressed APA drastically reduces, in a calcium dependent manner, fl-Aβ but not APP IntraCellular Domain in a cell-free model of Aβ production. In agreement with the above data, we show that recombinant APA degrades fl-Aβ in a pl302-sensitive manner. Interestingly, we also show that EC33 and pl302 lower staurosporine-stimulated activation of caspase-3 in wild-type fibroblasts but not in βAPP/β-amyloid precursor protein-like protein 2 (APLP2) double knockout fibroblasts, suggesting that protecting endogenous fl-Aβ physiological production triggers neuroprotective phenotype. By contrast, EC33 does not modify staurosporine-induced caspase-3 activation in wild-type and Swedish-mutated βAPP-HEK293 expressing cells that display exacerbated production of Aβ. Overall, our data establish that APA contributes to the N-terminal truncation of Aβ and suggest that this cleavage is likely abrogating a protective function associated with physiological but not supraphysiological levels of genuine fl-Aβ peptides. [ABSTRACT FROM AUTHOR]

The physiological functions of human TCRVγ9Vδ2 γδ lymphocytes reactive to non-peptide phosphoantigens contribute to cancer immunosurveillance and immunotherapy. However, their regulation by mesenchymal stem cells (MSC), multipotent and immunomodulatory progenitor cells able to infiltrate tumors, has not been investigated so far. By analyzing freshly isolated TCRVγ9Vδ2 lymphocytes and primary cell lines stimulated with synthetic phosphoantigen or B-cell lymphoma cell lines in the presence of MSC, we demonstrated that MSC were potent suppressors of γδ-cell proliferation, cytokine production and cytolytic responses in vitro. This inhibition was mediated by the COX-2-dependent production of prostaglandin E2 (PGE) and by MSC through EP2 and EP4 inhibitory receptors expressed by Vγ9Vδ2 T lymphocytes. COX-2 expression and PGE production by MSC were not constitutive, but were induced by IFN-γ and TNF-α secreted by activated Vγ9Vδ2 T cells. This regulatory cross-talk between MSC and Vγ9Vδ2 T lymphocytes involving PGE could be of importance for the antitumor and antimicrobial activities of γδ T cells. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Continuous treatment with the anti-tumor necrosis factor alpha (anti-TNFalpha) antibody infliximab is efficacious in ankylosing spondylitis (AS), whereas treatment discontinuation results in disease relapse, with variable delay. This study was undertaken to compare the efficacy of continuous treatment with infliximab with that of a treatment regimen adapted to symptom recurrence. Methotrexate (MTX) in combination with infliximab was also tested. METHODS: Patients with active AS were randomly assigned at week 0 to receive infliximab every 6 weeks (continuous treatment) or upon symptom recurrence (on-demand treatment), following infusions at weeks 4, 6, and 10. Patients in the on-demand group were randomly assigned to receive either MTX in combination with infliximab or infliximab alone. Patients were monitored for 1 year. The primary end point was the proportion of patients who met the ASsessment in AS International Working Group criteria for 20% improvement (ASAS20) at week 58. RESULTS: Of 247 patients, 124 were assigned to receive infliximab every 6 weeks and 123 to receive on-demand treatment. Among the latter, 62 received MTX, and 61 received infliximab alone. A greater proportion of patients receiving infliximab every 6 weeks fulfilled ASAS20 response criteria at week 58 than did patients receiving on-demand treatment (75% versus 46%; P < 0.0001). Patients in the continuous treatment group received more infliximab infusions after week 10 than did those in the on-demand group (mean +/- SD 5.8 +/- 2.2 versus 3.5 +/- 2; P < 0.0001). Addition of MTX did not significantly affect the proportion of patients with an ASAS20 response at week 58, nor the number of infliximab infusions administered. CONCLUSION: These findings indicate that continuous treatment of AS with infliximab is more efficacious than on-demand treatment, and that the addition of MTX to infliximab provides no significant benefit. [ABSTRACT FROM AUTHOR]

Phosphoantigens are mycobacterial non-peptide antigens that might enhance the immunogenicity of current subunit candidate vaccines for tuberculosis. However, their testing requires monkeys, the only animal models suitable for γδ T cell responses to mycobacteria. Thus here, the immunogenicity of 6-kDa early secretory antigenic target-mycolyl transferase complex antigen 85B (ESAT-6-Ag85B) (H-1 hybrid) fusion protein associated or not to a synthetic phosphoantigen was compared by a prime-boost regimen of two groups of eight cynomolgus. Although phosphoantigen activated immediately a strong release of systemic Th1 cytokines (IL-2, IL-6, IFN-γ, TNF-α), it further anergized blood γδ T lymphocytes selectively. By contrast, the hybrid H-1 induced only memory αβ T cell responses, regardless of phosphoantigen. These latter essentially comprised cytotoxic T lymphocytes specific for Ag85B (on average + 430 cells/million PBMC) and few IFN-γ-secreting cells (+ 40 cells/million PBMC, equally specific for ESAT-6 and for Ag85B). Hence, in macaques, a prime-boost with the H-1/phosphoantigen subunit combination induces two waves of immune responses, successively by γδ T and αβ T lymphocytes. [ABSTRACT FROM AUTHOR]

Although γδ T cells express clonally distributed T-cell receptors (TCRs), a hallmark of adaptive immunity, they are classically considered as innate-like effectors, owing to the high frequency of preactivated γδ T cells, with restricted antigen recognition repertoire in particular tissue locations. Actually, such features are shared only by a fraction of γδ T-cell subsets located in the skin and reproductive organ mucosa in rodents or in peripheral blood in humans. By contrast, other γδ subsets, e.g. those found in rodent and human spleen, show diverse antigenic reactivity patterns and mixed naive/memory phenotypes. Thus, γδ T cells are made of both ‘primitive’ subsets endowed with innate-like properties and ‘evolved’ subsets able to mount anamnestic responses like conventional major histocompatibility complex-restricted αβ T cells. In this article, we show that human γδ T cells, although heterogeneous, do share recurrent innate features that distinguish them from mainstream αβ T cells. In particular, most of them are activated on TCR- or natural killer receptor-mediated recognition of a restricted set of conserved yet poorly defined endogenous stress determinants. This rather simple recognition mechanism allows human γδ T cells to discriminate healthy cells from altered cells and to exert a variety of immunostimulatory or regulatory functions. The recent availability of synthetic γδ T-cell agonists mimicking these natural stress-induced ligands have fostered development of immunotherapeutic strategies, with broad indications against infectious and tumor diseases, which are briefly reviewed here. [ABSTRACT FROM AUTHOR]

As first defensive line, monocytes are a pivotal cell population of innate immunity. Monocyte activation can be relevant to a range of immune conditions and responses. Here we present new insights into the activation of monocytes by a series of phosphonic acid-terminated, phosphorus-containing dendrimers. Various dendritic or subdendritic structures were synthesized and tested, revealing the basic structural requirements for monocyte activation. We showed that multivalent character and phosphonic acid capping of dendrimers are crucial for monocyte targeting and activation. Confocal videomicroscopy showed that a fluorescein-tagged dendrimer binds to isolated monocytes and gets internalized within a few seconds. We also found that dendrimers follow the phagolysosomial route during internalization by monocytes. Finally, we performed fluorescence resonance energy transfer (FRET) experiments between a specifically designed fluorescent dendrimer and phycoerythrin-coupled anti-bodies. We showed that the typical innate Toll-like receptor (TLR)-2 is clearly involved, but not alone, in the sensing of dendrimers by monocytes. In conclusion, phosphorus-containing dendrimers appear as precisely tunable nanobiotools able to target and activate human innate immunity and thus prove to be good candidates to develop new drugs for immunotherapies. [ABSTRACT FROM AUTHOR]

Aminopeptidase A (APA) is involved in the maturation of angiotensin III, a peptide which seems to be implicated in blood pressure regulation at the brain level. Therefore APA inhibitors are potential new antihypertensive agents with possible novel applications. With the aim of enhancing the bioavailability and potency of EC 33, the APA inhibitor (Ki = 300 nm) initially used in the earlier studies, we have synthesized new non-peptidic inhibitors able to interact with the S1 and Ssubsites of the targeted enzyme. Compound10a, (3S,4S)-3-amino-4-mercapto-6-phenyl-hexane-1-sulfonic acid was obtained using an asymmetric synthesis. Inhibitor10aexhibits a Ki value of 30 nm. [ABSTRACT FROM AUTHOR]

The effect of angiotensin (Ang) IV, an inhibitor of insulin-regulated aminopeptidase (IRAP), on extracellular dopamine levels in the striatum of freely moving rats was examined using in vivo microdialysis. The Ang IV was administered locally in the striatum through the microdialysis probe. A concentration-dependent (10–100 µ m) increase in extracellular striatal dopamine was observed. The effect of Ang II (10–100 µ m), which has only a weak affinity for IRAP, was similar to that observed for Ang IV. The effects of both peptides could not be blocked by the AT1 antagonist candesartan (10 n m and 1 µ m) nor by the AT2 antagonist S-(+)-1-([4-(dimethylamino)-3-methylphenyl]methyl)-5-(diphenyl-acetyl)-4,5,6,7-tetrahydro-1H-amidazo(4,5-c) pyridine-6-carboxylic acid (1 µ m), suggesting that the observed effects are both AT1 and AT2 independent. The effect of Ang II could be blocked by the aminopeptidase-A inhibitor (S)-3-amino-4-mercaptobutylsulphonic acid as well as the aminopeptidase-N inhibitor 2-amino-4-methylsulphonylbutane thiol, indicating that the effect of Ang II is mediated via metabolism into Ang IV. Other IRAP inhibitors, such as Divalinal-Ang IV and LVV-haemorphin-7, had similar effects on extracellular dopamine levels as compared with Ang IV. We propose a role for IRAP as mediator for the effects of Ang IV and related peptides on extracellular dopamine levels in the striatum of the rat. [ABSTRACT FROM AUTHOR]

Three zinc metallopeptidases are implicated in the regulation of fluid homeostasis and vascular tone and represent interesting targets for the treatment of chronic heart failure. We have previously reported the synthesis of a triple inhibitor able to simultaneously inhibit neprilysin (NEP, EC 3.4.24.11), angiotensin-converting enzyme (ACE, EC 3.4.15.1) and endothelin-converting enzyme (ECE-1, EC 3.4.24.71) with nanomolar potency towards NEP and ACE and a lesser affinity for ECE. Here, we report the optimization and biological activities of analogs derived from lead compound 1 (2S)-2-[(2R)-2-((1S)-5-bromo-indan-1-yl)-3-mercapto-propionylamino]-3- (1H-indol-3-yl)-propionic acid by a structural approach. Among several inhibitors, compound 21, (2S)-2-[(2R)-2-((1S)-5-bromo-indan-1-yl)-3-mercapto-propionylamino]-3-(1H-pyrrolo[2,3-b]pyridin-3-yl)-propionic acid was selected by taking into account its good molecular adaptation with the recently published structures of the three vasopeptidases. This optimization procedure led to an improved pharmacologic activity when compared with 1. [ABSTRACT FROM AUTHOR]

Investigates the inhibition of zinc-containing exopeptidases and endopeptidases by alpha-aminophosphinic compound. Crystallization of alpha-aminophosphinic compound with thermolysin; Mode of zinc recognition by the phosphinic moiety; Role of the free alpha-amino group in the formation of enzyme-inhibitor complexes.

Summary. The use of von Willebrand factor [VWF antigen (WF:Ag)] measurement as a marker of endothelial cell activation for monitoring hypertensive pregnancies is limited by the poor definition of reference values. We reassessed these reference values using different assays, and those of the propeptide (VWF:Ag II) and factor VIII coagulant activity (factor VIII:C), in a large population of normal pregnancies, at 3-week intervals of gestational age. Plasminogen activator inhibitors (PAI-1 and PAI-2) were measured in parallel. Blood was collected at single time points between 12 weeks and delivery in 306 women undergoing normal singleton pregnancy. For clinical purposes, the VWF:Ag reference values were assay independent and the influence of ABO blood group on VWF:Ag or factor VIII:c was found to be limited during the third trimester. VWF:Ag II was not influenced by the ABO blood group. The ratio, VWF:Ag/factor VIII:C was close to 1·0 throughout pregnancy. In contrast, VWF:Ag II increased more slowly than VWF:Ag and the ratio of VWF:Ag II to VWF:Ag in plasma decreased from 1·00 to 0·5 at term. PAI-1 and PAI-2 increased with gestational age, but PAI-2 decreased during the last 2 weeks, indicating physiological placental regression at the very end of pregnancy. [ABSTRACT FROM AUTHOR]

Mistletoe extracts have immunomodulatory activity. We show that nontoxic concentrations of Viscum album extracts increase natural killer (NK) cell-mediated killing of tumor cells but spare nontarget cells from NK lysis. The compounds responsible for this bioactivity were isolated from mistletoe and characterized. They have low molecular mass and are thermostable and protease-resistant. After complete purification by HPLC, they were identified by tandem MS as viscotoxins A1, A2 and A3 (VTA1, VTA2 and VTA3, respectively). Whereas micromolar concentrations of these viscotoxins are cytotoxic to the targets, the bioactivity with respect to NK lysis is within the nanomolar range and differs between viscotoxin isoforms: VTA1 (85 nm), VTA2 (18 nm) and VTA3 (8 nm). Microphysiometry and assays of cell killing indicate that, within such nontoxic concentrations, viscotoxins do not activate NK cells, but act on cell conjugates to increase the resulting lysis. [ABSTRACT FROM AUTHOR]