Impact of Lactic Acid Bacteria on Dendritic Cells from Allergic Patients in an Experimental Model of Intestinal Epithelium

Lactic acid bacteria (LAB) are Gram positive nonpathogenic commensal organisms present in human gastrointestinal tract. In vivo, LAB are separated from antigen-presenting cells such as dendritic cells (DC) by the intestinal epithelial barrier. In this study, the impact of one LAB strain (Lactobacillus casei ATCC393) on human monocyte-derived DC from allergic and healthy donors was assessed by using a polarized epithelium model. Confocal and flow cytometer analyses showed that immature DC efficiently captured FITC-labelled L. casei through the epithelial layer. After interaction with L. casei, DC acquired a partial maturation status (i.e., CD86 and CD54 increase) and increased their interleukin (IL)-10 and IL-12 production. Interestingly, after activation by L. casei in the presence of experimental epithelium, DC from allergic patients instructed autologous naïve CD4(+) T cells to produce more interferon-γ than without the epithelium. Thus by modulating human DC reactivity, LAB and intestinal epithelium might modify T cell immune response and regulate the development of allergic reaction

Exosome release of β-catenin: a novel mechanism that antagonizes Wnt signaling

The tetraspanins CD9 and CD82 suppress Wnt signaling by promoting the discharge of β-catenin from cells

Problem z „ponowoczesnością”: pusty spór formalny czy zmiana charakteru egzystencji ludzkiej? [The problem with „postmodernity”: empty formal dispute or change in human existence?]

The present article poses an attempt of conceptualization the cognitive and normative basis of postmodernity. The primary aim is the demonstration that the post- modernization of the western culture recasts the fundamental parameters of social life and therefore also changes the ways of reflecting the human existence. In order to demonstrate this dependency I intend to portray modernity as a period, which tried to preserve the stabile structure of being of the Middle Ages by reproducing a centralized cultural order. Postmodern thinking tries to reach beyond metaphysically founded forms of social life and therefore attempts to decentralize the stabile structures of human existence. This is a very risky but also a very inspiring stride for the philosophical discourse, which one should – despite the awkward rhetoric of several postmodernists – appreciate as one of the most important challenges of contemporary philosophy

La résistance du piment (Capsicum annuum L.) à Phytophthora capsici Leon. XI. Réponse de 5 lignées de piment à une « fraction élicitrice » ; influence de la dose d’éliciteur et efficacité de la protection induite vis-à-vis de plusieurs souches du parasite

Dans l’étude de l’intéraction Piment - Phytophthora capsici, une voie d’approche intéressante réside dans l’utilisation de fractions issues du filtrat de culture du champignon et capables d’induire chez la plante une protection plus ou moins efficace vis-à-vis du parasite. Nous avons étudié l’efficacité de la fraction G4 (MOLOT et al., 1980 b) sur organes foliaires maintenus en survie sur l’eau. L’effet obtenu dépend de plusieurs facteurs ; choix de la souche contaminatrice de P. capsici, dose d’inoculum, quantité de G4 et lignées de piment. Le niveau de résistance acquise peut être partiellement surmonté par des doses massives d’inoculum (tabl. 1). Dans différentes conditions, l’effet optimum de protection s’observe avec des doses de G4 de l’ordre de 10 à 15 μg par feuille dans une goutte de 25 μl (tabl. 1 et 2 ; fig. 1). Les feuilles de variétés résistantes, principalement celles de « L 29 », répondent toujours mieux à l’éliciteur que celles de « Yolo Wonder », variété sensible (tabl. 2). Chez « Phyo 636 », variété résistante, l’état de résistance induite s’exprime plus ou moins selon la souche contaminatrice utilisée, mais il apparaît indépendant de l’agressivité de celle-ci (tabl. 3). Il est suggéré la possibilité de baser un programme de sélection sur la recherche de l’inductibilité.In the pepper - Phytophthora capsici interaction, some fractions were found from P. capsici culture filtrate (for instance G4) to induce resistance in the host. Tests were made with cotyledons or leaves floating on water : The G4 fraction was placed on the abaxial face and, after 24 hours, the foliar organs were infected by zoospore suspension or mycelial fragments. In order to evaluate the level of induced resistance, low zoospore concentration was preferable (tabl. 1). Induced resistance was optimum with 10 to 15 μg G4 per leaf organ (tabl. 1 & 2 ; fig. 1). Leaves of resistant pepper lines (specially « L 29 ») were more easily inducible than « Yolo Wonder » (tabl. 2). For « Phyo 636 », induced resistance depended on the isolates used for inoculation (but not on its aggressiveness (tabl. 3). It is suggested that a pepper selection program could be based on the inducibility : tests with floating leaves treated or not with elicitors

TLR9 expressed on plasma membrane acts as a negative regulator of human B cell response.

International audienceToll-like receptors (TLRs) are positioned at the interface between innate and adaptive immunity. Unlike others, those such as TLR9, that recognize nucleic acids, are confined to the endosomal compartment and are scarce on the cell surface. Here, we present evidence for TLR9 expression on the plasma membrane of B cells. In contrast to endosomal TLR9, cell surface TLR9 does not bind CpG-B oligodeoxynucleotides. After B cell-receptor (BCR) stimulation, TLR9 was translocated into lipid rafts with the BCR, suggesting that it could serve as a co-receptor for BCR. Nevertheless, stimulation of B cells with anti-TLR9 antibodies did not modify the BCR-induced responses despite up-regulation of tyrosine phosphorylation of proteins. However, CpG-B activation of B cells, acting synergistically with BCR signals, was inhibited by anti-TLR9 stimulation. Induction of CD25 expression and proliferation of B cells were thus down-regulated by the engagement of cell surface TLR9. Overall, our results indicate that TLR9 expressed on the plasma membrane of B cells might be a negative regulator of endosomal TLR9, and could provide a novel control by which activation of autoreactive B cells is restrained

Could abatacept directly target expanded plasmablasts in IgG4-related disease?

International audienc

Chitin particles are multifaceted immune adjuvants.

International audienceChitin is a ubiquitous polysaccharide in fungi, insects, allergens, and parasites that is released at sites of infection. Its role in the generation of tissue inflammation, however, is not fully understood. We hypothesized that chitin is an important adjuvant for adaptive immunity. Mice were injected with a solution of ovalbumin and chitin. We used in vivo and ex vivo/in vitro approaches to characterize the ability of chitin fragments to foster adaptive immune responses against ovalbumin and compared these responses to those induced by aluminum hydroxide (alum). In vivo, ovalbumin challenge caused an eosinophil-rich pulmonary inflammatory response, Th2 cytokine elaboration, IgE induction, and mucus metaplasia in mice that had been sensitized with ovalbumin plus chitin or ovalbumin plus alum. Toll-like receptor-2, MyD88, and IL-17A played critical roles in the chitin-induced responses, and MyD88 and IL-17A played critical roles in the alum-induced responses. In vitro, CD4(+) T cells from mice sensitized with ovalbumin plus chitin were incubated with ovalbumin-stimulated bone marrow-derived dendritic cells. In these experiments, CD4(+) T-cell proliferation, IL-5, IL-13, IFN-γ, and IL-17A production were appreciated. Toll-like receptor-2, MyD88, and IL-17A played critical roles in these in vitro adjuvant properties of chitin. TLR-2 was required for cell proliferation, whereas IL-17 and TLR-2 were required for cytokine elaboration. IL-17A also inhibited the generation of adaptive Th1 responses. These studies demonstrate that chitin is a potent multifaceted adjuvant that induces adaptive Th2, Th1, and Th17 immune responses. They also demonstrate that the adjuvant properties of chitin are mediated by a pathway(s) that involves and is regulated by TLR-2, MyD88, and IL-17A

B-cell lymphopenia is associated with a low response rate to abatacept in patients with rheumatoid arthritis.

International audienc

Abatacept efficacy in rheumatoid arthritis is dependent upon baseline blood B-cell levels.

International audienc