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Borgers H.,Biomedical science Group | Moens L.,Biomedical science Group | Picard C.,Institute National Of Sante Et Of Recherche Medicale | Picard C.,University of Paris Descartes | And 9 more authors.
Clinical Immunology | Year: 2010

We evaluated a multiplexed bead-based assay (xMAP® Pneumococcal Immunity assay from Luminex) for the simultaneous determination of antibodies against 14 capsular polysaccharides. Post-vaccination (Pneumovax®) antibody concentrations were measured in 35 healthy children, 40 healthy adults, 99 consecutive patients with increased susceptibility to respiratory infection, and 24 patients with a deficient anti-polysaccharide antibody response. The serotype-specific lower 5th percentile (cutoff) value for the post-immunization antibody concentration was determined in healthy individuals. Eleven of 99 patients (11%) failed to mount a response that was > 5th percentile of controls for at least 6 of the 14 serotypes tested, whereas only 3 of 75 controls (4%) failed to do so. All patients with known anti-polysaccharide antibody deficiency failed to mount a response that was > 5th percentile of controls for at least 6 of the 14 serotypes tested. The XMAP® pneumococcal immunity panel appears useful for identifying individuals with a low response to the unconjugated pneumococcal vaccine. © 2009 Elsevier Inc. All rights reserved.

Fourcade J.,University of Pittsburgh | Sun Z.,University of Pittsburgh | Pagliano O.,University of Pittsburgh | Guillaume P.,University of Lausanne | And 6 more authors.
Cancer Research | Year: 2012

Cytotoxic T cells that are present in tumors and capable of recognizing tumor epitopes are nevertheless generally impotent in eliciting tumor rejection. Thus, identifying the immune escape mechanisms responsible for inducing tumor-specific CD8 + T-cell dysfunction may reveal effective strategies for immune therapy. The inhibitory receptors PD-1 and Tim-3 are known to negatively regulate CD8 + T-cell responses directed against the well-characterized tumor antigen NY-ESO-1. Here, we report that the upregulation of the inhibitory molecule BTLA also plays a critical role in restricting NY-ESO-1-specific CD8 + T-cell expansion and function in melanoma. BTLA-expressing PD-1 +Tim-3 - CD8 + T cells represented the largest subset of NY-ESO-1-specific CD8 + T cells in patients with melanoma. These cells were partially dysfunctional, producing less IFN-γ than BTLA - T cells but more IFN-γ, TNF, and interleukin-2 than the highly dysfunctional subset expressing all three receptors. Expression of BTLA did not increase with higher T-cell dysfunction or upon cognate antigen stimulation, as it does with PD-1, suggesting that BTLA upregulation occurs independently of functional exhaustion driven by high antigen load. Added with PD-1 and Tim-3 blockades, BTLA blockade enhanced the expansion, proliferation, and cytokine production of NY-ESO-1-specific CD8 + T cells. Collectively, our findings indicate that targeting BTLA along with the PD-1 and Tim-3 pathways is critical to reverse an important mechanism of immune escape in patients with advanced melanoma. ©2011 AACR.

Detante O.,Institute National Of Sante Et Of Recherche Medicale | Detante O.,Joseph Fourier University | Valable S.,Institute National Of Sante Et Of Recherche Medicale | Valable S.,Joseph Fourier University | And 18 more authors.
Stem Cells Translational Medicine | Year: 2012

Human mesenchymal stem cells (hMSCs) have strong potential for cell therapy after stroke. Tracking stem cells in vivo following a graft can provide insight into many issues regarding optimal route and/or dosing. hMSCs were labeled for magnetic resonance imaging (MRI) and histology with micrometer-sized superparamagnetic iron oxides (M-SPIOs) that contained a fluorophore. We assessed whether M-SPIO labeling obtained without the use of a transfection agent induced any cell damage in clinical-grade hMSCs and whether it may be useful for in vivo MRI studies after stroke. M-SPIOs provided efficient intracellular hMSC labeling and did not modify cell viability, phenotype, or in vitro differentiation capacity. Following grafting in a rat model of stroke, labeled hMSCs could be detected using both in vivo MRI and fluorescent microscopy until 4 weeks following transplantation. However, whereas good label stability and unaffected hMSC viability were observed in vitro, grafted hMSCs may die and release iron particles in vivo. © AlphaMed Press.

PubMed | Institute National Of Sante Et Of Recherche Medicale
Type: Evaluation Studies | Journal: European journal of pediatrics | Year: 2012

West syndrome or infantile spasms is one of the most frequent epileptic syndromes in the first year of life. The clinical symptoms of infantile spasms are very different than any other type of seizure because of both the absence of paroxysmal motor phenomena (i.e., as in a convulsion) and the lack of significant duration of loss of consciousness (i.e., as in absence epilepsy). Infantile spasms may lead to misdiagnosis by pediatricians and other primary care providers. We assessed the missed diagnoses prior to the diagnosis of infantile spasms. We hypothesized that a delay in treatment may have consequences on neurologic outcome. We conducted a multicenter, retrospective, observational study to evaluate occurrence of misdiagnosis and its possible consequences. We performed a multivariate analysis to evaluate the risk for the outcome 2years after the diagnosis of infantile spasms. We included 83 infants over a 5-year period. The majority of consulted physicians (301 of 362) did not suggest any specific diagnosis while the others suggested gastroesophageal reflux (7%), constipation (7%), or colitis (3%). Results indicated that a poor outcome was related to a delay in diagnosis, which was observed regardless of the existence of cognitive involvement prior to the start of infantile spasms (Relative Risk: RR 12.08 [1.52-96.3]). These results highlight the importance of making an early diagnosis of infantile spasms.

PubMed | Institute National Of Sante Et Of Recherche Medicale
Type: Evaluation Studies | Journal: Clinical cancer research : an official journal of the American Association for Cancer Research | Year: 2010

NY-ESO-1 (ESO), a tumor-specific antigen of the cancer/testis group, is presently viewed as an important model antigen for the development of generic anticancer vaccines. The ESO(119-143) region is immunodominant following immunization with a recombinant ESO vaccine. In this study, we generated DRB1*0101/ESO(119-143) tetramers and used them to assess CD4 T-cell responses in vaccinated patients expressing DRB1*0101 (DR1).We generated tetramers of DRB1*0101 incorporating peptide ESO(119-143) using a previously described strategy. We assessed ESO(119-143)-specific CD4 T cells in peptide-stimulated postvaccine cultures using the tetramers. We isolated DR1/ESO(119-143) tetramer(+) cells by cell sorting and characterized them functionally. We assessed vaccine-induced CD4(+) DR1/ESO(119-143) tetramer(+) T cells ex vivo and characterized them phenotypically.Staining of cultures from vaccinated patients with DR1/ESO(119-143) tetramers identified vaccine-induced CD4 T cells. Tetramer(+) cells isolated by cell sorting were of T(H)1 type and efficiently recognized full-length ESO. We identified ESO(123-137) as the minimal optimal epitope recognized by DR1-restricted ESO-specific CD4 T cells. By assessing DR1/ESO(119-143) tetramer(+) cells using T cell receptor (TCR) chain variable region (V)-specific antibodies, we identified several frequently used V. Finally, direct ex vivo staining of patients CD4 T cells with tetramers allowed the direct quantification and phenotyping of vaccine-induced ESO-specific CD4 T cells.The development of DR1/ESO(119-143) tetramers, allowing the direct visualization, isolation, and characterization of ESO-specific CD4 T cells, will be instrumental for the evaluation of spontaneous and vaccine-induced immune responses to this important tumor antigen in DR1-expressing patients.

PubMed | Institute National Of Sante Et Of Recherche Medicale
Type: Journal Article | Journal: FASEB journal : official publication of the Federation of American Societies for Experimental Biology | Year: 2010

The purpose of this study was to assess the direct effect of CCL18, a chemokine elevated in allergic diseases and induced by Th2 cytokines, on the polarization of human CD4(+) T cells. Purified human T cells from healthy subjects were pretreated or not with CCL18, and evaluated for cytokine production. CCL18-pretreated memory but not naive CD4(+) T cells exhibited an increased production of IL-10 (12.3 2.6 vs. 5.6 0.9 ng/ml for medium) and TGF-1 but not IL-4, IFN-, and IL-17 compared with control cells. Pretreatment of highly purified CD4(+)CD25(-) memory T cells with CCL18 led to their conversion to CD4(+)CD25(+)Foxp3(+) regulatory T cells able to inhibit the proliferation of CD4(+)CD25(-) effector T cells by both cytokine and cell contact-dependent mechanisms. However, this regulatory effect of CCL18 was lost when T cells originated from allergic subjects in relation with a decreased binding of CCL18 to these cells [0.7 0.3 mean fluorescence intensity (MFI)] as compared to those from healthy subjects (6.0 1.7 MFI). This study is the first to define a chemokine that generates adaptive regulatory T cells from CD4(+)CD25(-) memory T cells. This mechanism appears defective in allergic patients and may underlie the decreased tolerance observed in allergic diseases.

PubMed | Institute National Of Sante Et Of Recherche Medicale
Type: | Journal: Journal of visualized experiments : JoVE | Year: 2012

Our goal is to obtain a comprehensive description of molecular processes occurring at cellular membranes in different biological functions. We aim at characterizing the complex organization and dynamics of the plasma membrane at single-molecule level, by developing analytic tools dedicated to Single-Particle Tracking (SPT) at high density: Multiple-Target Tracing (MTT). Single-molecule videomicroscopy, offering millisecond and nanometric resolution, allows a detailed representation of membrane organization by accurately mapping descriptors such as cell receptors localization, mobility, confinement or interactions. We revisited SPT, both experimentally and algorithmically. Experimental aspects included optimizing setup and cell labeling, with a particular emphasis on reaching the highest possible labeling density, in order to provide a dynamic snapshot of molecular dynamics as it occurs within the membrane. Algorithmic issues concerned each step used for rebuilding trajectories: peaks detection, estimation and reconnection, addressed by specific tools from image analysis. Implementing deflation after detection allows rescuing peaks initially hidden by neighboring, stronger peaks. Of note, improving detection directly impacts reconnection, by reducing gaps within trajectories. Performances have been evaluated using Monte-Carlo simulations for various labeling density and noise values, which typically represent the two major limitations for parallel measurements at high spatiotemporal resolution. The nanometric accuracy obtained for single molecules, using either successive on/off photoswitching or non-linear optics, can deliver exhaustive observations. This is the basis of nanoscopy methods such as STORM, PALM, RESOLFT or STED, which may often require imaging fixed samples. The central task is the detection and estimation of diffraction-limited peaks emanating from single-molecules. Hence, providing adequate assumptions such as handling a constant positional accuracy instead of Brownian motion, MTT is straightforwardly suited for nanoscopic analyses. Furthermore, MTT can fundamentally be used at any scale: not only for molecules, but also for cells or animals, for instance. Hence, MTT is a powerful tracking algorithm that finds applications at molecular and cellular scales.

PubMed | Institute National Of Sante Et Of Recherche Medicale
Type: Journal Article | Journal: Breast cancer research and treatment | Year: 2011

Germline mutations in BRCA1/2 confer a high risk of breast cancer (BC), but the magnitude of this risk varies according to various factors. Although controversial, there are data to support the hypothesis of allelic-risk heterogeneity. We assessed variation in BC risk according to the location of mutations recorded in the French study GENEPSO. Since the women in this study were selected from high-risk families, oversampling of affected women was eliminated by using a weighted Cox-regression model. Women were censored at the date of diagnosis when affected by any cancer, or the date of interview when unaffected. A total of 990 women were selected for the analysis: 379 were classified as affected, 611 as unaffected. For BRCA1, there was some evidence of a central region where the risk of BC is lower (codons 374-1161) (HR=0.59, P=0.04). For BRCA2, there was a strong evidence for a region at decreased risk (codons 957-1827) (HR=0.35, P=0.005) and for one at increased risk (codons 2546-2968) (HR=3.56, P=0.01). Moreover, we found an important association between radiation exposure from chest X-rays and BC risk (HR=4.29, P<10(-3)) and a positive association between smoking more than 21 pack-years and BC risk (HR=2.09, P=0.04). No significant variation in BC risk associated with chest X-ray exposure, smoking, and alcohol consumption was found according to the location of the mutation in BRCA1 and BRCA2. Our findings are consistent with those suggesting that the risk of BC is lower in the central regions of BRCA1/2. A new high-risk region in BRCA2 is described. Taking into account environmental and lifestyle modifiers, the location of mutations might be important in the clinical management of BRCA mutation carriers.

PubMed | Institute National Of Sante Et Of Recherche Medicale
Type: Journal Article | Journal: American journal of physiology. Heart and circulatory physiology | Year: 2011

We examined structure, composition, and endothelial function in cerebral arterioles after 4 wk of chronic renal failure (CRF) in a well-defined murine model (C57BL/6J and apolipoprotein E knockout female mice). We also determined quantitative expression of endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (on serine 1177 and threonine 495), and caveolin-1; quantitative expression of markers of vascular inflammation or oxidative stress [Rock-1, Rock-2, VCAM-1, and peroxisome proliferator-activated receptor- (PPAR)]; and the plasma concentration of L-arginine and asymmetric dimethylarginine (ADMA). Our hypothesis was that endothelial function would be impaired in cerebral arterioles during CRF following either a decrease in NO production (through alteration of eNOS expression or regulation) or an increase in NO degradation (due to oxidative stress or vascular inflammation). Endothelium-dependent relaxation was impaired during CRF, but endothelium-independent relaxation was not. CRF had no effect on cerebral arteriolar structure and composition. Quantitative expressions of eNOS, eNOS phosphorylated on serine 1177, caveolin-1, Rock-1, Rock-2, and VCAM-1 were similar in CRF and non-CRF mice. In contrast, quantitative expression of PPAR (which exercises a protective role on blood vessels) was significantly lower in CRF mice, whereas quantitative expression of eNOS phosphorylated on the threonine 495 (the inactive form of eNOS) was significantly higher. Lastly, the plasma concentration of ADMA (a uremic toxin and an endogenous inhibitor of eNOS) was elevated and plasma concentration of L-arginine was low in CRF. In conclusion, endothelial function is impaired in a mouse model of early stage CRF. These alterations may be related (at least in part) to a decrease in NO production.

PubMed | Institute National Of Sante Et Of Recherche Medicale
Type: Journal Article | Journal: Diabetes | Year: 2010

Maturity onset diabetes of the young type 3 (MODY3) is a consequence of heterozygous germline mutation in HNF1A. A subtype of hepatocellular adenoma (HCA) is also caused by biallelic somatic HNF1A mutations (H-HCA), and rare HCA may be related to MODY3. To better understand a relationship between the development of MODY3 and HCA, we compared both germline and somatic spectra of HNF1A mutations.We compared 151 somatic HNF1A mutations in HCA with 364 germline mutations described in MODY3. We searched for genotoxic and oxidative stress features in HCA and surrounding liver tissue.A spectrum of HNF1A somatic mutations significantly differed from the germline changes in MODY3. In HCA, we identified a specific hot spot at codon 206, nonsense and frameshift mutations mainly in the NH(2)-terminal part, and almost all amino acid substitutions were restricted to the POU-H domain. The high frequency of G-to-T tranversions, predominantly found on the nontranscribed DNA strand, suggested a genotoxic mechanism. However, no features of oxidative stress were observed in the nontumor liver tissue. Finally, in a few MODY3 patients with HNF1A germline mutation leading to amino acid substitutions outside the POU-H domain, we identified a different subtype of HCA either with a gp130 and/or CTNNB1 activating mutation.Germline HNF1A mutations could be associated with different molecular subtypes of HCA. H-HCA showed mutations profoundly inactivating hepatocyte nuclear factor-1alpha function; they are associated with a genotoxic signature suggesting a specific toxicant exposure that could be associated with genetic predisposition.

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