Inhibition of Neutrophil Recruitment Partially Explained by Impaired Mobilization from Bone Marrow and Reduced Chemokine Levels

Rapid activation of the innate immune system is critical for an efficient host response to invading pathogens. However, the inflammatory reaction has to be strictly controlled to minimize harmful immunopathology. A number of mediators including the cytokine interleukin-27 (IL-27) appear to be responsible for limitation and resolution of inflammation. Despite increasing knowledge of its suppressive effects on T cells, the influence on neutrophils and macrophages is poorly understood. To determine the role of IL-27 in innate immune responses we analysed the effect of IL-27 in a T cell independent model of zymosan-induced peritonitis. Early administration of recombinant IL-27 strongly reduced the number of neutrophils recruited to the peritoneal cavity after zymosan application as well as the neutrophil frequency in the blood. Simultaneously, IL-27 reduced the release of neutrophils from the bone marrow upon inflammation. Although cytokine levels were not affected by IL-27 treatment, the levels of the chemokines KC, MCP-1 and MIP-1α in the peritoneal fluid were strongly decreased. These findings demonstrate that IL-27 is able to control mobilisation and recruitment of neutrophils into the peritoneal cavity and identify a novel mechanism to limit inflammation caused by innate immune cells

Facilitated Peptide Transport via the Mucosal Epithelium

A hallmark of autoimmunity is the breakdown of tolerance and generation of effector responses against self-antigens. Re-establishment of tolerance in autoimmune disorders was always the most desired treatment option; however, despite many efforts, clinical trials have been largely unsuccessful. This also applies to the generation of oral tolerance, which seems to be a default response type of the mucosa-associated lymphoid tissues to harmless antigens. In this study, we report improved efficacy of oral tolerance induction by coupling antigen with the newly identified mucosal carrier peptide 13C. Antigen coupled to 13C is efficiently taken up in the gastrointestinal tract and could be visualized in cells of the lamina propria. Oral, rectal, or nasal treatment effectively induced the proliferation of antigen-specific T cells with some increase in the frequency of regulatory T cells. In a model of delayed-type hypersensitivity, especially intrarectal tolerization treatment resulted in reduced footpad swelling, demonstrating a moderate tolerogenic effect of mucosal treatment with 13C coupled antigen. Coupling of antigens to a transmucosal carrier, therefore, is a promising tool to improve the efficacy of vaccination via mucosal surfaces

Anti-Inflammatory Effects of IL-27 in Zymosan-Induced Peritonitis: Inhibition of Neutrophil Recruitment Partially Explained by Impaired Mobilization from Bone Marrow and Reduced Chemokine Levels.

Rapid activation of the innate immune system is critical for an efficient host response to invading pathogens. However, the inflammatory reaction has to be strictly controlled to minimize harmful immunopathology. A number of mediators including the cytokine interleukin-27 (IL-27) appear to be responsible for limitation and resolution of inflammation. Despite increasing knowledge of its suppressive effects on T cells, the influence on neutrophils and macrophages is poorly understood. To determine the role of IL-27 in innate immune responses we analysed the effect of IL-27 in a T cell independent model of zymosan-induced peritonitis. Early administration of recombinant IL-27 strongly reduced the number of neutrophils recruited to the peritoneal cavity after zymosan application as well as the neutrophil frequency in the blood. Simultaneously, IL-27 reduced the release of neutrophils from the bone marrow upon inflammation. Although cytokine levels were not affected by IL-27 treatment, the levels of the chemokines KC, MCP-1 and MIP-1α in the peritoneal fluid were strongly decreased. These findings demonstrate that IL-27 is able to control mobilisation and recruitment of neutrophils into the peritoneal cavity and identify a novel mechanism to limit inflammation caused by innate immune cells

Surface-modified yeast cells: A novel eukaryotic carrier for oral application.

The effective targeting and subsequent binding of particulate carriers to M cells in Peyer's patches of the gut is a prerequisite for the development of oral delivery systems. We have established a novel carrier system based on cell surface expression of the β1-integrin binding domain of invasins derived from Yersinia enterocolitica and Yersinia pseudotuberculosis on the yeast Saccharomyces cerevisiae. All invasin derivatives were shown to be effectively expressed on the cell surface and recombinant yeast cells showed improved binding to both human HEp-2 cells and M-like cells in vitro. Among the different derivatives tested, the integrin-binding domain of Y. enterocolitica invasin proved to be the most effective and was able to target Peyer's patches in vivo. In conclusion, cell surface-modified yeasts might provide a novel bioadhesive, eukaryotic carrier system for efficient and targeted delivery of either antigens or drugs via the oral route

Influence of IL-27 on the inflammatory response in sterile zymosan-induced peritonitis.

<p>IL-27 was either given together with zymosan (zymosan +IL-27) or 12 h before zymosan application into the peritoneum (zymosan +preIL-27). The control group received zymosan only. <b>A.</b> Representative FACS plots for peritoneal neutrophils and macrophages isolated from the peritoneal lavage 12h after induction of peritonitis. GR1+CD11b+ cells are defined as neutrophils, CD11b+ single positive cells as macrophages. Cell frequencies within the neutrophil gate are depicted. <b>B.</b> Absolute number of neutrophils in the peritoneal lavage at various time points after zymosan injection. Results are pooled from four independent experiments and represent mean ± S.E.M (n = 4–12). <b>C.</b> Absolute number of macrophages in the peritoneal lavage at various time points after zymosan injection. Pooled data from four independent experiments, mean ± S.E.M. (n = 4–12). Mann–Whitney test was used to compare between groups, *p<0.05, ** p<0.01.</p

Decreased levels of KC, MCP-1 and MIP-1α in the peritoneal lavage after IL-27 pretreatment.

<p>12 h after induction of peritonitis or vehicle injection, the peritoneal cavity was flushed with 5ml PBS and levels of the indicated chemokines were measured by multiplex bead array assay. Results are pooled from three independent experiments; given are means ± S.D (n = 6–8). Mann–Whitney test was used to compare between groups, *p<0.05, ** p<0.01, ***p<0.005.</p

IL-27 pre-treatment does not affect the cell numbers of T, B, NK and dendritic cells in the peritoneal lavage.

<p>Cells in the peritoneal lavage were collected 12 h after the administration of zymosan with or without pre-treatment with rIL-27 and measured by FACS analysis. Results from three different experiments are combined, given are means ± S.D (n = 4–9). Mann–Whitney test was used to compare between groups, *p<0.05, ** p<0.01, ***p<0.005.</p

IL-27 pre-treatment decreases neutrophil accumulation in the murine blood and temporarily in the bone marrow during zymosan-induced peritonitis.

<p>Dot plots show the gating for neutrophils in the FACS analyses of blood cells and bone marrow cells (at at 12h and 4h after zymosan injection, respectively). Cell frequencies within the gate are given for the exemplary FACS plots. <b>A.</b> Absolute numbers of blood neutrophils in the blood of vehicle-treated animals (vehicle) 12h after injection and animals with or without pre-treatment with rIL-27 monitored 4–48h after injection of zymosan. Results from four different experiments are combined; given are means ± S.E.M (n = 8–11). <b>B.</b> Absolute numbers of neutrophils in the bone marrow of vehicle-treated animals (12h after vehicle injection) and 4–48h after injection of zymosan with or without pre-treatment with rIL-27. Results from four different experiments are combined; given are means ± S.E.M (n = 8–11). Mann–Whitney test was used to compare between groups, *p<0.05, ** p<0.01, ***p<0.005.</p