Dysregulation of Toll-like receptor (TLR) responses to pathogens can lead to pathological inflammation or to immune hyporesponsiveness and susceptibility to infections, and may affect adaptive immune responses. TLRs are therefore attractive therapeutic targets. We assessed the potential of the TLR co-receptor CD14 as a target for therapeutics by investigating the magnitude of its influence on TLR responses. We studied the interaction of CD14 with TLR2 by conducting peptide screening and site-directed mutagenesis analysis and found TLR2 leucine-rich repeats 5, 9, 15, and 20 involved in interaction with CD14. Peptides representing these regions interacted with CD14 and enhanced TLR2- and TLR4-mediated proinflammatory responses to bacterial pathogens in vitro. Notably, the peptides' immune boosting capacity helped to rescue proinflammatory responses of immunosuppressed sepsis patients ex vivo. In vivo, peptide treatment increased phagocyte recruitment and accelerated bacterial clearance in murine models of Gram-negative and Gram-positive bacterial peritonitis. Up-modulating CD14's co-receptor activity with TLR2-derived peptides also enhanced antigen-induced dendritic cell (DC) maturation and interleukin-2 production and, most notably, differentially affected DC cytokine profile upon antigen stimulation, promoting a T helper 1-skewed adaptive immune response. Biochemical, cell imaging, and molecular docking studies showed that peptide binding to CD14 accelerates microbial ligand transfer from CD14 to TLR2, resulting in increased and sustained ligand occupancy of TLR2 and receptor clustering for signaling. These findings reveal the influence that CD14 exerts on TLR activities and describe a potential therapeutic strategy to amplify responses to different pathogens mediated by different TLRs by targeting the common TLR co-receptor, CD14.

Circulating malignant Sézary lymphocytes result from a clonal proliferation of memory/activated CD4+CD45RO+ T lymphocytes primarily involving the skin. Recently, the CD158k/KIR3DL2 cell surface receptor has been identified to phenotypically characterize these cells. We previously described a mAb termed SC5 that identifies an unknown early activation cell membrane molecule. It is expressed selectively by T lymphocytes isolated from healthy individuals upon activation, and by circulating Sézary syndrome lymphocytes. In addition, we found that SC5 mAb was reactive with all resting T lymphocytes once permeabilized, indicating that SC5 mAb-reactive molecule might present distinct cellular localization according to the T cell activation status. In this study, we show for the first time that SC5 mAb recognizes the intermediate filament protein vimentin when exported to the extracellular side of the plasma membrane of viable Sézary malignant cells. We demonstrate that SC5 mAb is unique as it reacts with both viable malignant lymphocytes and apoptotic T cells. As vimentin is also detected rapidly at the cell membrane surface after normal T lymphocyte activation, it suggests that its extracellular detection on Sézary cells could be a consequence of their constitutive activation status. Finally, as a probable outcome of vimentin cell surface expression, autoantibodies against vimentin were found in the sera of Sézary syndrome patients.

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The diagnostic of Amyotrophic lateral sclerosis (ALS) remains based on clinical and neurophysiological observations. The actual delay between the onset of the symptoms and diagnosis is about 1 year, preventing early inclusion of patients into clinical trials and early care of the disease. Therefore, finding biomarkers with high sensitivity and specificity remains urgent. In our study, we looked for peptide biomarkers in plasma samples using reverse phase magnetic beads (C18 and C8) and MALDI-TOF mass spectrometry analysis. From a set of ALS patients (n=30) and healthy age-matched controls (n=30), C18- or C8-SVM-based models for ALS diagnostic were constructed on the base of the minimum of the most discriminant peaks. These two SVM-based models end up in excellent separations between the 2 groups of patients (recognition capability overall classes > 97%) and classify blinded samples (10 ALS and 10 healthy age-matched controls) with very high sensitivities and specificities (>90%). Some of these discriminant peaks have been identified by Mass Spectrometry (MS) analyses and correspond to (or are fragments of) major plasma proteins, partly linked to the blood coagulation.

Saturnisporins SA II and SA 1V are the major components of the 20‐residue peptaibol mixture isolated from a culture of the fungus Trichoderma saturnisporum. These peptides exhibit antibiotic activity against Staphylococcus aureus. Their sequences were derived from unequivocal methodology implying the combined use of positive ion FAB mass spectrometry and NMR: the majority of the sequences result from mass spectrometry fragmentations and the location of isomeric residues arises either from analysis of ROESY cross‐peaks between contiguous amide protons or from heteronuclear 2J or 3J 1H‐13C couplings detected in long‐range 1H‐13C COSY experiments. The sequence specific 1H and 13C NMR assignments are described. Saturnisporins SA II and SA IV exhibit similar secondary structures, as deduced from their ROESY patterns and 3JNHCαH coupling constant values, together with amide hydrogen‐deuterium exchange rates and temperature coefficients of amide and carbonyl groups. An overall α‐helical structure is proposed, maintaining two regions of distortion to this regular structure; i)the N‐terminal part, which contains 310 and mixed α‐310 turns, and ii) the Aib10‐Val15 region, including a Pro residue which accommodates a bend stabilized by two 310 H‐bonds.