Effect of Saccharomyces cerevisiae var. Boulardii and b-galactomannan oligosaccharide on porcine intestinal epithelial and dendritic cells challenged in vitro with Escherichia coli F4 (K88)

Probiotic and prebiotics, often called “immune-enhancing” feed additives, are believed to deal with pathogens, preventing the need of an immune response and reducing tissue damage. In this study, we investigated if a recently developed b-galactomannan (bGM) had a similar protective role compared to Saccharomyces cerevisiae var. Boulardii (Scb), a proven probiotic, in the context of enterotoxigenic Escherichia coli (ETEC) infection. ETEC causes inflammation, diarrhea and intestinal damage in piglets, resulting in large economic loses worldwide. We observed that Scb and bGM products inhibited in vitro adhesion of ETEC on cell surface of porcine intestinal IPI-2I cells. Our data showed that Scb and bGM decreased the mRNA ETEC-induced gene expression of pro-inflammatory cytokines TNF-a, IL-6, GM-CSF and chemokines CCL2, CCL20 and CXCL8 on intestinal IPI-2I. Furthermore, we investigated the putative immunomodulatory role of Scb and bGM on porcine monocyte-derived dendritic cells (DCs) per se and under infection conditions. We observed a slight up-regulation of mRNA for TNF-a and CCR7 receptor after coincubation of DC with Scb and bGM. However, no differences were found in DC activation upon ETEC infection and Scb or bGM co-culture. Therefore, our results indicate that, similar to probiotic Scb, prebiotic bGM may protect intestinal epithelial cells against intestinal pathogens. Finally, although these products may modulate DC activation, their effect under ETEC challenge conditions remains to be elucidated.This work was supported by grants from the French National Institute for Agricultural Research (INRA, France) and grant AGL 2009-11936 of the Ministerio de Ciencia e Innovación (MICIIN, Spain). We gratefully acknowledge Dr I. Badiola (CReSA) for providing ETEC GN1034 strain and Dr J. Domínguez-Juncal (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, INIA, Madrid, Spain) for kindly providing antibodies for pig cell surface markers.info:eu-repo/semantics/publishedVersio

Early immune response following Salmonella enterica subspecies enterica serovar Typhimurium infection in porcine jejunal gut loops

Salmonella enterica subspecies enterica serovar Typhimurium, commonly called S. Typhimurium, can cause intestinal infections in humans and various animal species such as swine. To analyze the host response to Salmonella infection in the pig we used an in vivo gut loop model, which allows the analysis of multiple immune responses within the same animal. Four jejunal gut-loops were each inoculated with 3×108 cfu of S. Typhimurium in 3 one-month-old piglets and mRNA expressions of various cytokines, chemokines, transcription factors, antimicrobial peptides, toll like and chemokine receptors were assessed by quantitative real-time PCR in the Peyer’s patch and the gut wall after 24 h. Several genes such as the newly cloned CCRL1/CCX-CKR were assessed for the first time in the pig at the mRNA level. Pro-inflammatory and T-helper type-1 (Th1) cytokine mRNA were expressed at higher levels in infected compared to non-infected control loops. Similarly, some B cell activation genes, NOD2 and toll like receptor 2 and 4 transcripts were more expressed in both tissues while TLR5 mRNA was down-regulated. Interestingly, CCL25 mRNA expression as well as the mRNA expressions of its receptors CCR9 and CCRL1 were decreased both in the Peyer’s patch and gut wall suggesting a potential Salmonella strategy to reduce lymphocyte homing to the intestine. In conclusion, these results provide insight into the porcine innate mucosal immune response to infection with entero-invasive microorganisms such as S. Typhimurium. In the future, this knowledge should help in the development of improved prophylactic and therapeutic approaches against porcine intestinal S. Typhimurium infections

Expression and immunogenicity of the mycobacterial Ag85B/ESAT-6 antigens produced in transgenic plants by elastin-like peptide fusion strategy.

International audienceThis study explored a novel system combining plant-based production and the elastin-like peptide (ELP) fusion strategy to produce vaccinal antigens against tuberculosis. Transgenic tobacco plants expressing the mycobacterial antigens Ag85B and ESAT-6 fused to ELP (TBAg-ELP) were generated. Purified TBAg-ELP was obtained by the highly efficient, cost-effective, inverse transition cycling (ICT) method and tested in mice. Furthermore, safety and immunogenicity of the crude tobacco leaf extracts were assessed in piglets. Antibodies recognizing mycobacterial antigens were produced in mice and piglets. A T-cell immune response able to recognize the native mycobacterial antigens was detected in mice. These findings showed that the native Ag85B and ESAT-6 mycobacterial B- and T-cell epitopes were conserved in the plant-expressed TBAg-ELP. This study presents the first results of an efficient plant-expression system, relying on the elastin-like peptide fusion strategy, to produce a safe and immunogenic mycobacterial Ag85B-ESAT-6 fusion protein as a potential vaccine candidate against tuberculosis

Study of CD4+ T Cell Response to the Tumor Antigen Cyclin B1

De nombreux antigènes de tumeur ont été identifiés depuis la découverte du premier antigène de tumeur humain il y a une vingtaine d’années, et plusieurs d’entre eux ont été utilisés comme antigène cible pour l’élaboration de vaccins thérapeutiques anti-Cancer. Cependant, les résultats des essais cliniques visant à évaluer l’efficacité de ces vaccins se sont la plupart du temps révélés décevants. Aussi, il reste indispensable d’identifier de nouveaux antigènes de tumeur cibles capables d’induire des réponses anti-Tumorales fortes et durables. Parmi les antigènes de tumeur considérés comme cibles potentielles pour un vaccin anti-Tumoral se trouve la Cycline B1, une protéine endogène impliquée dans la régulation du cycle cellulaire. Normalement exprimée de façon transitoire dans les cellules saines en division, cette protéine est surexprimée dans diverses tumeurs et est indispensable au développement tumoral. De plus, des réponses immunitaires spontanées spécifiques de cette protéine ont été observées chez des patients atteints de cancer. L’objectif de ma thèse était de caractériser la réponse en lymphocytes T CD4+, qui jouent un rôle capital dans la réponse immunitaire anti-Tumorale, spécifique de la Cycline B1 humaine chez des sujets sains et chez des patients atteints de cancer. Nous avons mis en évidence l’existence, chez des individus sains, de deux populations de lymphocytes T CD4+ préexistants spécifiques de cette protéine, à savoir des lymphocytes T CD4+ naïfs et des lymphocytes T CD4+ mémoires, cette seconde population lymphocytaire se retrouvant également chez des patients atteints de cancer. De multiples épitopes T CD4+ ont été identifiés dans cette protéine, et étaient différemment reconnus par ces deux populations de lymphocytes T CD4+. En outre, des anticorps IgG anti-Cycline B1 ont été détectés chez des patients atteints de cancer comme chez des individus sains, sans différence significative dans les taux d’anticorps entre ces deux catégories de sujets. Ainsi, cette étude montre que la Cycline B1 est un antigène de tumeur caractérisé par un profil singulier de réponses immunitaires, et confirme le potentiel vaccinal de cette protéine pour l’élaboration d’un vaccin anti-Cancer.Many tumor antigens have been identified since the discovery of the first human antigen about twenty years ago, and some of them have been used as targets for the development of therapeutic cancer vaccines. However, most of the time, the results of clinical trials designed to assess the efficacy of these vaccines proved to be disappointing. Thus, it is still necessary to identify new tumor antigens able to induce strong and long-Lasting anti-Tumor responses that could be used as targets for cancer vaccine. Cyclin B1, an endogenous protein involved in cell cycle regulation, is one of the tumor antigens which are currently considered as potential targets for a cancer vaccine. Usually expressed transiently in healthy dividing cells, this protein is overexpressed in numerous tumors and is necessary for tumor development. Moreover, Cyclin B1 specific spontaneaous immune responses have been observed in cancer patients. My PhD work aimed at characterizing the response of CD4+ T cells, which play a major role in anti-Tumor immune responses, specific to human Cyclin B1 both in healthy individuals and cancer patients. We showed that, in healthy individuals, there exists two pre-Existing Cyclin B1 specific CD4+ T cell populations, namely naive CD4+ T cells and memory CD4+ T cells, the latter lymphocyte population being also found in cancer patients. Multiple CD4+ T cell epitopes have been identified in this protein, and were differently recognized by these two CD4+ T cell populations. Besides, anti-Cyclin B1 IgG antibodies have been detected both in healthy individuals and in cancer patients, without significant differences in antibody levels between these two groups of donors. Therefore, this work shows that Cyclin B1 is a tumor antigen characterized by a singular pattern of immune responses, and confirms the potential of this protein as a target for a cancer vaccine

Cellules épithéliales du colostrum de truie : Sensibilité au virus GET et propriétés in vitro

National audienc

Cellules épithéliales du colostrum de truie : Sensibilité au virus GET et propriétés in vitro

National audienc

Devenir des cellules colostrales chez le porc nouveau-né

National audienc

Les récepteurs aux éléments microbiens dans l'intestin : analyse de leur expression dans les différents segments et organes lymphoïdes et le long de l'axe crypto-villositaire

Session 3 : Dialogue agresseurs-hôtes, adaptation réciproquesCommunication oraleabsen

Activité chimiotactique de lait d'artiodactyle sur les lymphocytes porcins

National audienc

An increase in milk IgA correlates with both pIgR expression and IgA plasma cell accumulation in the lactating mammary gland of PRM/Alf mice

Chantier qualité GAIn mice, during late pregnancy and lactation, maternal precursors of IgA-containing cells (cIgA-cells) are primed in the gut and home to the mammary gland where they secrete IgA. In turn, the ensuing increase in milk IgA mediates immune protection of the newborn gastrointestinal tract. PRM/Alf is an inbred mouse strain which exhibits a substantial post-natal intestinal lengthening which develops throughout the neonatal suckling period, suggesting that the availability of cIg-A cells and the level of protective IgA in milk might also be increased. We confirmed that PRM/Alf milk contains higher amounts of IgA than C57BL/6J throughout lactation, concomitantly with an increase of pIgR on epithelial cells and a higher density of cIgA-cells in the PRM/Alf mammary gland. Furthermore, a search for variations in cellular and humoral factors implicated in regulating cIgA-cell migration towards the mammary gland, including the vascular addressins MAdCAM-1 (mucosal addressin cell adhesion molecule-1) and VCAM-1 (vascular cell adhesion molecule-1) as well as the mucosal epithelial chemokine CCL28, did not reveal any quantitative differences in expression between PRM/Alf and C57BL/6J mice strains. Thus our results indicate that these factors are not limiting in the recruitment of cIgA-cells released from the elongated gut of PRM/Alf mice. In the context of intestinal lengthening, these findings strengthen the notion of an entero-mammary gland link, where the neonatal gut is protected by the maternal gut through the immune function of the mammary gland