ovalbumin and lipoteichoic-acid

Topics: Animals; Bronchoalveolar Lavage Fluid; Cytokines; Female; Hypersensitivity; Inflammation; Intracellular Signaling Peptides and Proteins; Lipopolysaccharides; Mice; Mice, Inbred C57BL; NF-kappa B; Ovalbumin; RAW 264.7 Cells; Teichoic Acids; Toll-Like Receptor 2

Topics: Allergens; Animals; Cell Movement; Chronic Disease; Disease Models, Animal; Enterotoxins; Eosinophils; Humans; Lipopolysaccharides; Male; Nasal Mucosa; Neutrophil Infiltration; Ovalbumin; Rabbits; Rhinitis; Sinusitis; Staphylococcus aureus; Teichoic Acids

Mannosylated ovalbumin (Man-OVA) prepared by modification of carboxyl groups with p-aminophenyl α-d-mannopyranoside shows an increase of net positive charge, which may enhance its binding to bacterial membrane. Thus, we aimed to investigate whether Man-OVA exerts antibacterial activity on Escherichia coli and Staphylococcus aureus via membrane-perturbing effect. Man-OVA inhibited the growth of E. coli and S. aureus, whereas ovalbumin (OVA) did not show any antibacterial activity. Moreover, Man-OVA induced an increase in the membrane permeability of E. coli and S. aureus, which was positively correlated to its bactericidal action. Morphological examination using scanning electron microscopy revealed that Man-OVA disrupted the bacterial membrane integrity. Destabilization of the lipopolysaccharide (LPS) layer and inhibition of lipoteichoic acid (LTA) biosynthesis in the cell wall increased the bactericidal effect of Man-OVA. In contrast to OVA, Man-OVA also induced leakage of bacterial membrane-mimicking liposomes. Color transformation of phospholipid/polydiacetylene membrane assay revealed that the membrane-interaction mode of Man-OVA was distinct from that of OVA. LPS and LTA suppressed the membrane-damaging activity of Man-OVA, whereas an increase in the Man-OVA concentration attenuated the inhibitory action of LPS and LTA. Taken together, our data indicate that the bactericidal activity of Man-OVA depends strongly on its ability to induce membrane permeability.

Topics: Anti-Bacterial Agents; Cell Membrane; Cell Wall; Escherichia coli; Lipopolysaccharides; Mannose; Microscopy, Electron, Scanning; Ovalbumin; Staphylococcus aureus; Teichoic Acids

The interplay between microbes and surface organs, such as the skin, shapes a complex immune system with several checks and balances. The first-line defense is mediated by innate immune pathways leading to inflammation. In the second phase specific T cells invade the infected organ, amplifying inflammation and defense. Consecutively, termination of inflammation is crucial to avoid chronic inflammation triggered by microbes, such as in patients with atopic dermatitis.. We aimed to elucidate how the Staphylococcus aureus-derived cell-wall component lipoteichoic acid (LTA) governs the second phase of immune responses when high concentrations of LTA access T cells directly through disrupted skin.. We analyzed the direct exposure of T cells to LTA in vitro. For in vivo analyses, we used fluorescein isothiocyanate contact hypersensitivity and ovalbumin-induced dermatitis as models for TH2-mediated cutaneous inflammation.. We observed that LTA potently suppressed T-lymphocyte activation in a Toll-like receptor 2-independent manner. LTA-exposed T cells did not proliferate and did not produce cytokines. Importantly, these T cells remained completely viable and were responsive to consecutive activation signals on subsequent removal of LTA. Thus LTA exposure resulted in temporary functional T-cell paralysis. In vivo experiments revealed that T-cell cytokine production and cutaneous recall responses were significantly suppressed by LTA.. We identified a new mechanism through which bacterial compounds directly but temporarily modulate adaptive immune responses.

Topics: Allergens; Animals; Cell Proliferation; Cytokines; Dermatitis, Atopic; Dermatitis, Contact; Fluorescein-5-isothiocyanate; Lipopolysaccharides; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Myeloid Differentiation Factor 88; Ovalbumin; Staphylococcus aureus; T-Lymphocytes; Teichoic Acids; Toll-Like Receptor 2

Prospective cohort studies suggest that children hospitalized in early life with severe infections are significantly more likely to develop recurrent wheezing and asthma.. Using an inhalational mouse model of allergic airways inflammation, we sought to determine the effect of viral and bacterial-associated molecular patterns on the magnitude of the allergic inflammatory response and whether this effect was age dependent.. BALB/c mice were sensitized by intranasal administration of endotoxin(low) ovalbumin (OVA) in the absence or presence of viral single-stranded (ss)RNA, lipoteichoic acid or flagellin as neonates (within the first 24 h of life) or as weanlings (4 weeks of age). Mice were challenged four times with OVA at 6 weeks of age and end-points (bronchoalveolar lavage cytology, histology, antigen-specific T and B cell responses) determined at 7 weeks of age.. Inhalational sensitization (<24 h or 4 weeks of age) and challenge with OVA induced a mild allergic inflammatory response in the airways as indicated by increased numbers of eosinophils and mucus cells, elevated serum OVA-specific IgG1, and production of T helper 2 (Th2) cytokines. Mice sensitized to endotoxin(low) OVA at birth in the presence of ssRNA or lipoteichoic acid, but not flagellin, showed an increase in the numbers of airway and tissue eosinophils, mucus producing cells and antigen-specific production of IL-13 as compared with mice exposed only to endotoxin(low) OVA. By contrast, all three TLR ligands failed to increase the magnitude of OVA-induced allergic inflammation in mice sensitized as weanlings.. Recognition of distinct microbial-associated patterns in early life may preferentially promote the de novo differentiation of bystander, antigen-specific CD4(+) T cells toward a Th2 phenotype, and promote an asthma-like phenotype upon cognate antigen exposure in later life.

Topics: Adjuvants, Immunologic; Animals; Animals, Newborn; Eosinophilia; Flagellin; Gene Expression; Hyperplasia; Hypersensitivity; Immunoglobulin G; Interferon-gamma; Interleukin-13; Interleukin-4; Interleukin-5; Lipopolysaccharides; Lung; Lymph Nodes; Membrane Glycoproteins; Mice; Mice, Inbred BALB C; Mucous Membrane; Ovalbumin; RNA, Viral; Teichoic Acids; Th2 Cells; Toll-Like Receptor 2; Toll-Like Receptor 7; Vaccination

Sublingual immunotherapy (SLIT) has been established in humans as a safe and efficacious treatment for type I respiratory allergies.. In this study, we compared three Toll-like receptor (TLR) 2 ligands (Pam3CSK4, Porphyromonas gingivalis lipopolysaccharide and lipoteichoic acid) as potential adjuvants for sublingual allergy vaccines.. These molecules were tested in co-cultures of adjuvant-pre-treated dendritic cells (DCs) with murine naïve CD4(+) T lymphocytes. Patterns of cytokine production, phenotype, proliferation and gene expression were analysed by ELISA, cytofluorometry and quantitative PCR, respectively. TLR2 ligands were subsequently tested in a model of SLIT in BALB/c mice sensitized with ovalbumin (OVA).. Among the three TLR2 ligands tested, the synthetic lipopeptide Pam3CSK4 is the most potent inducer of IL-12p35 and IL-10 gene expression in murine bone marrow-derived DCs, as well as in purified oral myeloid DCs. Only Pam3CSK4-treated DCs induce IFN-gamma and IL-10 secretion by naïve CD4(+) T cells. Sublingual administration of Pam3CSK4 together with the antigen in BALB/c mice sensitized to OVA decreases airway hyperresponsiveness as well as OVA-specific T-helper type 2 (Th2) responses in cervical lymph nodes dramatically.. Pam3CSK4 induces Th1/regulatory T cell responses, and as such, is a valid candidate adjuvant for sublingual allergy vaccines.

Topics: Adjuvants, Immunologic; Administration, Sublingual; Animals; Antigen Presentation; Asthma; Bronchial Hyperreactivity; CD4-Positive T-Lymphocytes; Cytokines; Dendritic Cells; Desensitization, Immunologic; Gene Expression; Humans; Interferon-gamma; Interleukin-10; Lipopeptides; Lipopolysaccharides; Lymph Nodes; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Ovalbumin; Porphyromonas gingivalis; T-Lymphocytes, Helper-Inducer; Teichoic Acids; Toll-Like Receptor 2

Human peripheral dendritic cells (DCs) are antigen-presenting cells with the ability to internalize antigen and present antigen-derived peptides to T cells. Human DCs express several receptors on the surface for endocytosis and other recognition receptors that bind to microbes or microbial products, which are internalized and processed. Here, we report the use of nanometer-size zeolite particles as a tool to study receptor-mediated endocytosis by the two subsets of immature DCs, myeloid (mDC) and plasmacytoid (pDC) dendritic cells. A major difference in receptor-mediated endocytosis was observed between the two populations of peripheral DCs. The pDC population demonstrated an almost complete lack of receptor-mediated endocytosis of zeolite particles, whereas the mDC population demonstrated a clear receptor-mediated endocytosis. Fc receptors are expressed by both peripheral DC populations and lipoteichoic acid (LTA) and lipopolysaccharide (LPS) are known ligands of the Toll-like receptor (TLR)-2 and TLR4, respectively, both TLRs expressed by human mDCs. An efficient receptor-mediated endocytosis of immunoglobulin G-, LTA-, and LPS-coated zeolite particles was observed by the mDC population and their endocytosing capacity depended strongly on the density of the ligand adsorbed onto the zeolite particles. In conclusion, an efficient receptor-mediated endocytosis was observed from the mDC population, whereas the pDCs demonstrated an almost complete lack of receptor-mediated endocytosis and nanometer-size dealuminated zeolite particles were a useful tool for studying receptor-mediated endocytosis in human peripheral DCs.

Topics: CD40 Antigens; Cytokines; Dendritic Cells; Endocytosis; Fluorescent Antibody Technique; Gene Expression Regulation; Humans; Lipopolysaccharides; Ovalbumin; Receptors, Cell Surface; Teichoic Acids; Zeolites

Allergic diseases are reported to be caused by a skew in the balance between T helper type 1 and 2 cells. Because some lactic acid bacteria have been shown to stimulate IL-12 (p70) production, which in turn shifts the balance between the T helper type 1 and 2 cell response from the latter to the former, they have the potential to either prevent or ameliorate disease conditions or both. They have therefore been extensively studied in the recent past for their probiotic activities. Nevertheless, much less information is available concerning the microbial factors that determine the strain-dependent ability to affect the production of cytokines. The objectives of our study were first to select potentially probiotic lactobacilli that strongly stimulate cytokine production in vitro, and then to determine whether the selected Lactobacillus strains could suppress antigen-specific IgE production in vivo by using allergic model animals. Finally, our investigation was extended to analyze which bacterial components were responsible for the observed biological activity. Twenty strains of heat-killed lactobacilli isolated from humans were screened for their stimulatory activity for the production of IL-12 (p70) by murine splenocytes in vitro. The results showed that some strains of Lactobacillus plantarum and Lactobacillus gasseri had a higher stimulatory activity for IL-12 (p70) production than the other lactobacilli tested; however, this effect was strain dependent rather than species dependent. Oral administration of the heat-killed strains that showed higher stimulatory activity for IL-12 (p70) production tended to reduce the serum antigen-specific IgE levels in ovalbumin-sensitized BALB/c mice compared with the controls. Among the lactobacilli tested, L. gasseri OLL2809 showed the highest activity in reducing the level of antigen-specific IgE. Furthermore, the stimulatory activity for IL-12 (p70) production was found to be reduced after treating the lactobacilli with N-acetyl-muramidase and to be positively correlated with the amount of peptidoglycan in the cells. The present data suggest that L. gasseri OLL2809 is a good candidate for potential probiotics in terms of either the prevention or amelioration of allergic diseases or both. In addition, the strain-dependent stimulatory activity for IL-12 (p70) production was found to be due, at least in part, to the amount of peptidoglycan present in the cells.

Topics: Animals; Cytokines; Endopeptidases; Freeze Drying; Hot Temperature; Hypersensitivity; Immunoglobulin E; Interleukin-12; Lactobacillus; Lipopolysaccharides; Male; Mice; Mice, Inbred BALB C; Ovalbumin; Peptidoglycan; Probiotics; Spleen; Teichoic Acids