SENS-IS, a 3D reconstituted epidermis based model for quantifying chemical sensitization potency: Reproducibility and predictivity results from an inter-laboratory study.

The SENS-IS test protocol for the in vitro detection of sensitizers is based on a reconstructed human skin model (Episkin) as the test system and on the analysis of the expression of a large panel of genes. Its excellent performance was initially demonstrated with a limited set of test chemicals. Further studies (described here) were organized to confirm these preliminary results and to obtain a detailed statistical analysis of the predictive capacity of the assay.

Genes specifically modulated in sensitized skins allow the detection of sensitizers in a reconstructed human skin model. Development of the SENS-IS assay.

Analysis of genes modulated during the sensitization process either on mice (LLNA) or human (blisters) combined with data mining has allowed the definition of a comprehensive panel of sensitization biomarkers. This set of genes includes already identified markers such as the ARE family and others not yet associated with the sensitization process (the so-called SENS-IS gene subset). The expression of this set of genes has been measured on reconstituted human epidermis models (Episkin) exposed to various sensitizers and non-sensitizers.

Epstein-Barr virus infection induces an increase of T regulatory type 1 cells in Hodgkin lymphoma patients.

Epstein-Barr Virus (EBV) is present in the neoplastic cells of around 20-30% of patients with Hodgkin Lymphoma (HL). Although, an immunosuppressive environment is currently described in HL patients, little is known concerning the regulatory mechanism induced by EBV proteins expression in tumour cells. This study aimed to investigate an association between regulatory Type 1 cells (Tr1) and EBV tissue positivity in HL patients.

Overexpression of Regulatory T Cells Type 1 (Tr1) Specific Markers in a Patient with HCV-Induced Hepatocellular Carcinoma.

Hepatitis C virus (HCV) is an important causative agent of liver disease, but factors that determine the resolution or progression of infection are poorly understood. In this study, we suggested that existence of immunosuppressive mechanisms, supported by regulatory T cells and especially the regulatory T cell 1 subset (Tr1), may explain the impaired immune response during infection and thus the fibrosis aggravation to hepatocellular carcinoma (HCC). Using quantitative real-time PCR, we investigated the intra-hepatic presence of Tr1 cells in biopsies from a genotype 1b infected patient followed for an 18-year period from cirrhosis to HCC.

Interleukin-7 regulates adipose tissue mass and insulin sensitivity in high-fat diet-fed mice through lymphocyte-dependent and independent mechanisms.

Although interleukin (IL)-7 is mostly known as a key regulator of lymphocyte homeostasis, we recently demonstrated that it also contributes to body weight regulation through a hypothalamic control. Previous studies have shown that IL-7 is produced by the human obese white adipose tissue (WAT) yet its potential role on WAT development and function in obesity remains unknown. Here, we first show that transgenic mice overexpressing IL-7 have reduced adipose tissue mass associated with glucose and insulin resistance.

EBV Latency II-derived peptides induce a specific CD4+ cytotoxic T-cell activity and not a CD4+ regulatory T-cell response.

Epstein-Barr virus (EBV) is associated with several malignant diseases that can be distinguished by their patterns of viral latent gene expression. We developed here an original peptidic approach to favor the induction of a specific CD4+ T-cell response against EBV latency II malignancies (Hodgkin's lymphoma, nasopharyngeal carcinoma, T/NK lymphoma). Previously, we selected 6 peptides derived from EBV nuclear antigen-1, latency membrane proteins (LMP)-1, and LMP-2 highly promiscuous for major histocompatibility complex class II molecules and showed their ability to induce interferon-γ-secreting CD4+ T cells.

Analysis of gene transcription in sera during chronic hepatitis C infection.

Alternative, non-invasive techniques are necessary to monitor the progression of liver disease during chronic hepatitis C. Firstly, because serum is the most accessible material for studies using qPCR in microplates, gene transcription was compared in 219 selected genes involved in the pathogenesis of hepatitis C virus (HCV) infection between sera, PBMCs and liver samples collected simultaneously from five patients infected chronically. Secondly, using sera, gene profiles were compared between HCV-infected patients (n = 10) and healthy controls (n = 10).

[Role of the Regulatory T lymphocytes in hepatitis C fibrosis progression].

Hepatitis C virus (HCV) becomes chronic in about 85 % of infected individuals, whereas only 15 % of infected people clear spontaneously the virus. The progression of hepatitis C to chronic status is associated to a profound down-regulation of CD4 and CD8 multispecific immune response. This immune defect may participate to the immune tolerance of VHC and consequently to its persistence.

Presence of HIV-1 Nef specific CD4 T cell response is associated with non-progression in HIV-1 infection.

The ex vivo response to three HLA-DR-restricted Nef peptides (Nef 66-97, Nef 133-159, Nef 180-202) and one HLA-DQ-restricted Nef peptide (Nef 56-68) was evaluated in 28 HIV-seropositive patients and 6 Long-term Non-Progressors (LTNPs). Analyzing specific proliferative response and IFN-gamma secretion, patients were identified as high responders, medium responders and non-responders to peptides. As high responder patients, LTNP patients showed strong proliferative response to all the Nef-peptides as strong IFN-gamma secretion.

Differential capacity of T cell priming in naive donors of promiscuous CD4+ T cell epitopes of HCV NS3 and Core proteins.

To understand the inter-individual and virus-independent variability of CD4+ T cell responses to HCV components, we evaluated the effect on these responses of HLA II molecules in uninfected healthy donors. Using HLA II-specific binding assays, we identified, in the Core and NS3 proteins, 21 long fragments and 24 15-mer peptides that bound to four to eight of the most preponderant HLA II molecules. We then evaluated the priming capacity of eight long promiscuous peptides in 12 HLA-unrelated healthy donors.

Determination of a HLA II promiscuous peptide cocktail as potential vaccine against EBV latency II malignancies.

The Epstein-Barr virus (EBV) is associated with several malignant diseases, which can be distinguished by their patterns of viral latent gene expression. The latency II program is limited to the expression of the nonimmunodominant antigens EBNA1, LMP1 and LMP2 and is seen in EBV-positive Hodgkin disease, nasopharyngeal carcinomas, and peripheral T/NK-cell lymphomas. CD4 T cells may play a crucial role in controlling these EBV latency II malignancies.

Host glucose metabolism mediates T4 and IL-7 action on Schistosoma mansoni development.

Interleukin (IL-)7 and thyroxin (T4) favor Schistosoma mansoni development. Their effect is similar, rather than identical; moreover, cotreatment acts synergistically on parasites. This questioned a common mediator to their action, which we hypothesized was host glucose metabolism.

Autoactivation of the Epstein-Barr virus oncogenic protein LMP1 during type II latency through opposite roles of the NF-kappaB and JNK signaling pathways.

Epstein-Barr virus (EBV) is associated with several human malignancies where it expresses limited subsets of latent proteins. Of the latent proteins, latent membrane protein 1 (LMP1) is a potent transforming protein that constitutively induces multiple cell signaling pathways and contributes to EBV-associated oncogenesis. Regulation of LMP1 expression has been extensively described during the type III latency of EBV.

Peptide-binding assays and HLA II transgenic Abeta degrees mice are consistent and complementary tools for identifying HLA II-restricted peptides.

The identification of MHC class II-restricted peptides has become a priority for the development of peptide-based prophylactic and therapeutic vaccines. The aim of this study was to assess the correlations between peptide-binding assays on purified HLA II molecules and immunization of human HLA II transgenic mice deficient in murine class II molecules (Abeta degrees ). We used as models two MHC class II-restricted peptides, one derived from the HIV Nef regulatory protein (Nef (56-68)) and the other from the Schistosoma mansoni 28-kDa glutathione-S-transferase (Sm28GST (190-211)).

Amplification of antibody responses to antigen using small multilamellar vesicles for delivery system.

New vaccines based on subunits, synthetic peptides, or DNA need innovative adjuvants or antigen delivery systems: Spherulites are multilamellar vesicles made of incompatible lipid bilayers without any aqueous core. In this study, we evaluated their ability to induce immune responses against human serum albumin (HSA). Mice were immunized by the intraperitoneal/intravenous route or subcutaneously with HSA without any adjuvant or in its encapsulated form.

A mouse model of human adaptive immune functions: HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-knockout mice.

HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-knockout mice were created and their immunological potential evaluated in response to hepatitis B DNA vaccine. Every single immunized mouse developed hepatitis B virus-specific antibodies, HLA-DR1-restricted helper, and HLA-A2.

Comparison of HLA-DR1-restricted T cell response induced in HLA-DR1 transgenic mice deficient for murine MHC class II and HLA-DR1 transgenic mice expressing endogenous murine MHC class II molecules.

Transgenic mice expressing human HLA class II molecules provide a useful model for identifying HLA-restricted CD4+ epitopes. However, the influence of endogenous murine H-2-restricted T cell responses on HLA-restricted responses is not known. In the present study, we show that HLA-DR1 transgenic mice deficient for H-2 class II expression (HLA-DR1+/+/IAbeta0/0) exhibit an equivalent expression level of the transgene HLA-DR1 and a similar diversity in the TCR repertoire, but a slightly different number of CD4+ peripheral T cells, when compared to HLA-DR1 transgenic mice in which H-2 class II molecules were retained (HLA-DR1+/+/IAbeta+/+).

Polypeptide semicarbazide glass slide microarrays: characterization and comparison with amine slides in serodetection studies.

We have described in the accompanying article the preparation of peptide-protein semicarbazide microarrays and their use for the simultaneous serodetection of antibodies directed against different pathogens. Here, we present a comparative study between semicarbazide and amine glass slides in an immunofluorescent serodetection assay using HIV (Gp120, Gp41), HCV (mix-HCV, core, NS3, and NS4), and HBV (HBs) recombinant antigens. Amine and semicarbazide surfaces displayed the same sensitivity for antibodies detection just after printing.

Peptide-protein microarrays for the simultaneous detection of pathogen infections.

We describe novel peptide-protein microarrays, which were fabricated using semicarbazide glass slides that permitted the immobilization of glyoxylyl peptides by site-specific ligation and the immobilization of proteins by physisorption. The arrays permitted the simultaneous serodetection of antibodies directed against hepatitis C virus (HCV core p21 15-45 peptide, NS4 1925-1947 peptide, core, NS3, NS4, and mixture of core, NS3, NS4, and NS5 antigens), hepatitis B virus (HBc, HBe, and HBs), human immunodeficiency virus (Gp41 and Gp120 for HIV-I and Gp36 for HIV-II), Epstein-Barr virus (VCAp18 153-176 peptide), and syphilis (rTpN47 and rTpN17) antigens using an immunofluorescence assay. Peptide-protein microarrays displayed high signal-to-noise ratios, sensitivities, and specificities for the detection of antibodies as revealed by the analysis of a collection of human sera referenced against these five pathogens.

A novel dominant-negative mutant form of Epstein-Barr virus latent membrane protein-1 (LMP1) selectively and differentially impairs LMP1 and TNF signaling pathways.

The latent membrane protein-1 (LMP1) is an integral membrane molecule expressed by Epstein-Barr virus (EBV) during viral latency and displays properties of a constitutively activated member of the TNF receptor family. LMP1 is required for B-cell or monocyte immortalization induced by EBV and is sufficient to transform rodent fibroblasts. Transforming potential of LMP1 is mediated by its cytoplasmic C-terminal domain, which activates various cellular signaling pathways including NFkappaB and JNK.

Prolactin-cytokine network in the defence against Acanthamoeba castellanii in murine microglia [corrected].

In the central nervous system, cytokine-primed microglia play a pivotal role in host defence against parasite infections. In this study, the effect of recombinant (r) prolactin (rPRL) and rIFN-gamma on A. castellanii infection in murine microglia was examined.

Early variations of host thyroxine and interleukin-7 favor Schistosoma mansoni development.

Schistosoma mansoni induces, in the vertebrate host, cutaneous production of interleukin-7 (IL-7), which is beneficial for parasite establishment and development. Infection of mice deficient in IL-7 expression leads to parasite dwarfism. Because similar findings were previously described in hypothyroid mice, this study aimed to elucidate the potential link between IL-7 and thyroid hormones (THs), using several models including hypo- and hyperthyroid mice, modified either transiently or constitutively.

IL-10 leads to a higher parasite persistence in a resistant mouse model of Leishmania major infection.

IL-10 is a cytokine secreted by a wide variety of cell types and has pleiotropic activities, mainly as a modulator of the immune response. In this study, we tested in a direct way the influence of IL-10 expression on Leishmania major infection in resistant mice. We report that C57BL/6 mice treated with a single inoculation of recombinant adenovirus vector-expressing viral IL-10 (Ad-vIL-10), 1 day before parasitic challenge, exhibited a dual effect on footpad swelling, characterized by a decrease on lesion size at the early stage of the infection, followed by a rapid increase of these lesions that attained the complete healing later in infection.

Complex network of cytokines activating murine microglial cell activity against Acanthamoeba castellani.

In the central nervous system, cytokine-primed microglia play a pivotal role in host defence against Acanthamoeba castellani infections. In this study, the effect of rIL-1beta, rIL-6 or rTNF-alpha, combined or not with rIFN-gamma, on A. castellani infection of murine microglia was examined.