Liquid-crystalline ordering of antimicrobial peptide-DNA complexes controls TLR9 activation.

Double-stranded DNA (dsDNA) can trigger the production of type I interferon (IFN) in plasmacytoid dendritic cells (pDCs) by binding to endosomal Toll-like receptor-9 (TLR9; refs , , , , ). It is also known that the formation of DNA-antimicrobial peptide complexes can lead to autoimmune diseases via amplification of pDC activation. Here, by combining X-ray scattering, computer simulations, microscopy and measurements of pDC IFN production, we demonstrate that a broad range of antimicrobial peptides and other cationic molecules cause similar effects, and elucidate the criteria for amplification. TLR9 activation depends on both the inter-DNA spacing and the multiplicity of parallel DNA ligands in the self-assembled liquid-crystalline complex. Complexes with a grill-like arrangement of DNA at the optimum spacing can interlock with multiple TLR9 like a zipper, leading to multivalent electrostatic interactions that drastically amplify binding and thereby the immune response. Our results suggest that TLR9 activation and thus TLR9-mediated immune responses can be modulated deterministically.

National survey of noncommunicable diseases in Seychelles 2013‐2014 (Seychelles Heart Study IV) : main findings

The 2013 survey addressed the following objectives: Primary objectives : a) Distribution of health behaviors related to NCDs, particularly tobacco use, alcohol drinking, and physical activity ; b) Distribution of the main modifiable risk factors of NCDs, particularly blood pressure, adiposity markers, diabetes and blood lipids ; c) Rates of awareness, treatment and control of hypertension, diabetes and dyslipidemia ; d) Comparison of findings in the survey 2013 with results in previous similar NCD surveys in 1989, 1994, 2004 ; e) Dietary patterns ; f) Knowledge, attitudes and practices related to NCDs and NCD risk factors. Secondary objectives : g) Assessment of indicators of quality of health (e.g. SF‐12) ; h) Assessment of psychological stress and relation with NCD ; i) Assessment of several indicators of frailty (e.g. handgrip strength test, chair strand test, functional limitations) ; j) Assessment of knowledge and level of agreement with current policies on tobacco control ; k) Use of public and private health care services, particularly for NCDs ; l) Exposure to advice on health behaviors given by health professionals at health care level ; m) Burden of chronic diseases not related to the main NCDs (e.g. musculoskeletal, mental health, etc) ; n) Screening of selected cancers ; o) Assessment of the kidney function ; p) Frequency of heart arrhythmias (one‐lead ECG) and heart murmurs (auscultation) ; q) Assessment of bone mineral density (ultrasound of calcaneus) ; r) Exposure of the population to mass media, particularly in relation to health programs, and use by the population of new communication technologies ; s) Assessment of a number of social variables and their association with the variables measured in the survey ; t) More generally, the survey provides broad information (medical, social, environment, etc) that can be useful for tailoring NCD prevention and control programs.

National Survey of Noncommunicable Diseases in Seychelles, 2013-2014 (Seychelles Heart Study IV) : methods and main findings

This report provides information on selected summary results of the National Survey of Noncommunicable Diseases in Seychelles in 2013‐2014 (Seychelles Heart Study IV). The survey is also referred shortly as the "2013 Survey" in this report. Overall crude results were reported in a comprehensive report in November 2014. Further detailed analyses and recommendations on particular topics will be performed separately.

Structure-Based, Rational Design of T Cell Receptors.

Adoptive cell transfer using engineered T cells is emerging as a promising treatment for metastatic melanoma. Such an approach allows one to introduce T cell receptor (TCR) modifications that, while maintaining the specificity for the targeted antigen, can enhance the binding and kinetic parameters for the interaction with peptides (p) bound to major histocompatibility complexes (MHC). Using the well-characterized 2C TCR/SIYR/H-2K(b) structure as a model system, we demonstrated that a binding free energy decomposition based on the MM-GBSA approach provides a detailed and reliable description of the TCR/pMHC interactions at the structural and thermodynamic levels. Starting from this result, we developed a new structure-based approach, to rationally design new TCR sequences, and applied it to the BC1 TCR targeting the HLA-A2 restricted NY-ESO-1157-165 cancer-testis epitope. Fifty-four percent of the designed sequence replacements exhibited improved pMHC binding as compared to the native TCR, with up to 150-fold increase in affinity, while preserving specificity. Genetically engineered CD8(+) T cells expressing these modified TCRs showed an improved functional activity compared to those expressing BC1 TCR. We measured maximum levels of activities for TCRs within the upper limit of natural affinity, K D = ∼1 - 5 μM. Beyond the affinity threshold at K D < 1 μM we observed an attenuation in cellular function, in line with the "half-life" model of T cell activation. Our computer-aided protein-engineering approach requires the 3D-structure of the TCR-pMHC complex of interest, which can be obtained from X-ray crystallography. We have also developed a homology modeling-based approach, TCRep 3D, to obtain accurate structural models of any TCR-pMHC complexes when experimental data is not available. Since the accuracy of the models depends on the prediction of the TCR orientation over pMHC, we have complemented the approach with a simplified rigid method to predict this orientation and successfully assessed it using all non-redundant TCR-pMHC crystal structures available. These methods potentially extend the use of our TCR engineering method to entire TCR repertoires for which no X-ray structure is available. We have also performed a steered molecular dynamics study of the unbinding of the TCR-pMHC complex to get a better understanding of how TCRs interact with pMHCs. This entire rational TCR design pipeline is now being used to produce rationally optimized TCRs for adoptive cell therapies of stage IV melanoma.