Jun-O Jin

Fucoidan Can Function as an Adjuvant In Vivo to Enhance Dendritic Cell Maturation and Function and Promote Antigen-Specific T Cell Immune Responses

Fucoidan, a sulfated polysaccharide purified from brown algae, has a variety of immune-modulation effects, including promoting antigen uptake and enhancing anti-viral and anti-tumor effects. However, the effect of fucoidan in vivo, especially its adjuvant effect on in vivo anti-tumor immune responses, was not fully investigated. In this study, we investigated the effect of fucoidan on the function of spleen dendritic cells (DCs) and its adjuvant effect in vivo. Systemic administration of fucoidan induced up-regulation of CD40, CD80 and CD86 expression and production of IL-6, IL-12 and TNF-α in spleen cDCs. Fucoidan also promoted the generation of IFN-γ-producing Th1 and Tc1 cells in an IL-12-dependent manner. When used as an adjuvant in vivo with ovalbumin (OVA) antigen, fucoidan promoted OVA-specific antibody production and primed IFN-γ production in OVA-specific T cells. Moreover, fucoidan enhanced OVA-induced up-regulation of MHC class I and II on spleen cDCs and strongly prompted the proliferation of OVA-specific CD4 and CD8 T cells. Finally, OVA immunization with fucoidan as adjuvant protected mice from the challenge with B16-OVA tumor cells. Taken together, these results suggest that fucoidan can function as an adjuvant to induce Th1 immune response and CTL activation, which may be useful in tumor vaccine development.

Interleukin-7 enhances the Th1 response to promote the development of Sjögren's syndrome-like autoimmune exocrinopathy in mice.

OBJECTIVE Although elevated interleukin-7 (IL-7) levels have been reported in patients with primary Sjögrens syndrome (SS), the role of IL-7 in this disease remains unclear. We undertook this study to characterize the previously unexplored role of IL-7 in the development and onset of primary SS using the C57BL/6.NOD-Aec1Aec2 (B6.NOD-Aec) mouse model, which recapitulates human primary SS. METHODS For gain-of-function studies, recombinant IL-7 or control phosphate buffered saline was injected intraperitoneally (IP) into 12-week-old B6.NOD-Aec mice for 8 weeks. For loss-of-function studies, anti-IL-7 receptor α-chain (anti-IL-7Rα) antibody or its isotype control IgG was administered IP into 16-week-old B6.NOD-Aec mice. Salivary flow measurement, histologic and flow cytometric analysis of salivary glands, and serum antinuclear antibody assay were performed to assess various disease parameters. RESULTS Administration of exogenous IL-7 accelerated the development of primary SS, whereas blockade of IL-7Rα signaling almost completely abolished the development of primary SS, based on salivary gland inflammation and apoptosis, autoantibody production, and secretory dysfunction. IL-7 positively regulated interferon-γ (IFNγ)-producing Th1 and CD8+ T cells in the salivary glands without affecting IL-17. Moreover, IL-7 enhanced the expression of CXCR3 ligands in a T cell- and IFNγ-dependent manner. Accordingly, IFNγ induced a human salivary gland epithelial cell line to produce CXCR3 ligands. IL-7 also increased the level of tumor necrosis factor α, another Th1-associated cytokine that can facilitate tissue destruction and inflammation. CONCLUSION IL-7 plays a pivotal pathogenic role in SS, which is underpinned by an enhanced Th1 response and IFNγ/CXCR3 ligand-mediated lymphocyte infiltration of target organs. These results suggest that targeting the IL-7 pathway may be a potential future strategy for preventing and treating SS.

Fucoidan from Macrocystis pyrifera Has Powerful Immune-Modulatory Effects Compared to Three Other Fucoidans

Fucoidan, a sulfated polysaccharide purified from brown algae, has a variety of immune-modulation effects, such as promoting activation of dendritic cells (DCs), natural killer (NK) cells and T cells, and enhancing anti-viral and anti-tumor responses. However, the immune-modulatory effect of fucoidan from different seaweed extracts has not been thoroughly analyzed and compared. We analyzed fucoidans obtained from Ascophyllum nodosum (A. nodosum), Macrocystis pyrifera (M. pyrifera), Undaria pinnatifida (U. pinnatifida) and Fucus vesiculosus (F. vesiculosus) for their effect on the apoptosis of human neutrophils, activation of mouse NK cells, maturation of spleen DCs, proliferation and activation of T cells, and the adjuvant effect in vivo. Fucoidans from M. pyrifera and U. pinnatifida strongly delayed human neutrophil apoptosis at low concentration, whereas fucoidans from A. nodosum and F. vesiculosus delayed human neutrophil apoptosis at higher concentration. Moreover, fucoidan from M. pyrifera promoted NK cell activation and cytotoxic activity against YAC-1 cells. In addition, M. pyrifera fucoidan induced the strongest activation of spleen DCs and T cells and ovalbumin (OVA) specific immune responses compared to other fucoidans. These data suggest that fucoidan from M. pyrifera can be potentially useful as a therapeutic agent for infectious diseases, cancer and an effective adjuvant for vaccine.

Interleukin-7 Enhances Th1 Response to Promote the Development of Sjӧgren’s Syndrome-Like Autoimmune Exocrinopathy

OBJECTIVE Although elevated interleukin-7 (IL-7) levels have been reported in patients with primary Sjögrens syndrome (SS), the role of IL-7 in this disease remains unclear. We undertook this study to characterize the previously unexplored role of IL-7 in the development and onset of primary SS using the C57BL/6.NOD-Aec1Aec2 (B6.NOD-Aec) mouse model, which recapitulates human primary SS. METHODS For gain-of-function studies, recombinant IL-7 or control phosphate buffered saline was injected intraperitoneally (IP) into 12-week-old B6.NOD-Aec mice for 8 weeks. For loss-of-function studies, anti-IL-7 receptor α-chain (anti-IL-7Rα) antibody or its isotype control IgG was administered IP into 16-week-old B6.NOD-Aec mice. Salivary flow measurement, histologic and flow cytometric analysis of salivary glands, and serum antinuclear antibody assay were performed to assess various disease parameters. RESULTS Administration of exogenous IL-7 accelerated the development of primary SS, whereas blockade of IL-7Rα signaling almost completely abolished the development of primary SS, based on salivary gland inflammation and apoptosis, autoantibody production, and secretory dysfunction. IL-7 positively regulated interferon-γ (IFNγ)-producing Th1 and CD8+ T cells in the salivary glands without affecting IL-17. Moreover, IL-7 enhanced the expression of CXCR3 ligands in a T cell- and IFNγ-dependent manner. Accordingly, IFNγ induced a human salivary gland epithelial cell line to produce CXCR3 ligands. IL-7 also increased the level of tumor necrosis factor α, another Th1-associated cytokine that can facilitate tissue destruction and inflammation. CONCLUSION IL-7 plays a pivotal pathogenic role in SS, which is underpinned by an enhanced Th1 response and IFNγ/CXCR3 ligand-mediated lymphocyte infiltration of target organs. These results suggest that targeting the IL-7 pathway may be a potential future strategy for preventing and treating SS.

Ascophyllan purified from Ascophyllum nodosum induces Th1 and Tc1 immune responses by promoting dendritic cell maturation.

Marine-derived sulfated polysaccharides have been shown to possess certain anti-virus, anti-tumor, anti-inflammatory and anti-coagulant activities. However, the in vivo immunomodulatory effects of marine-derived pure compounds have been less well characterized. In this study, we investigated the effect of ascophyllan, a sulfated polysaccharide purified from Ascophyllum nodosum, on the maturation of mouse dendritic cells (DCs) in vitro and in vivo. Ascophyllan induced up-regulation of co-stimulatory molecules and production of pro-inflammatory cytokines in bone marrow-derived DCs (BMDCs). Moreover, in vivo administration of ascophyllan promotes up-regulation of CD40, CD80, CD86, MHC class I and MHC class II and production of IL-6, IL-12 and TNF-α in spleen cDCs. Interestingly, ascophyllan induced a higher degree of co-stimulatory molecule up-regulation and pro-inflammatory cytokine production than fucoidan, a marine-derived polysaccharide with well-defined effect for promoting DC maturation. Ascophyllan also promoted the generation of IFN-γ-producing Th1 and Tc1 cells in the presence of DCs in an IL-12-dependent manner. Finally, myeloid differentiation primary response 88 (MyD88) signaling pathway was essential for DC maturation induced by ascophyllan. Taken together, these results demonstrate that ascophyllan induces DC maturation, and consequently enhances Th1 and Tc1 responses in vivo. This knowledge could facilitate the development of novel therapeutic strategies to combat infectious diseases and cancer.

BDCA1-Positive Dendritic Cells (DCs) Represent a Unique Human Myeloid DC Subset That Induces Innate and Adaptive Immune Responses to Staphylococcus aureus Infection

ABSTRACT Staphylococcus aureus bloodstream infection (bacteremia) is a major cause of morbidity and mortality and places substantial cost burdens on health care systems. The role of peripheral blood dendritic cells (PBDCs) in the immune responses against S. aureus infection has not been well characterized. In this study, we demonstrated that BDCA1+ myeloid DCs (mDCs) represent a unique PBDC subset that can induce immune responses against S. aureus infection. BDCA1+ mDCs could engulf S. aureus and strongly upregulated the expression of costimulatory molecules and production of proinflammatory cytokines. Furthermore, BDCA1+ mDCs expressed high levels of major histocompatibility complex (MHC) class I and II molecules in response to S. aureus and greatly promoted proliferation and gamma interferon (IFN-γ) production in CD4 and CD8 T cells. Moreover, BDCA1+ mDCs expressed higher levels of Toll-like receptor 2 (TLR-2) and scavenger receptor A (SR-A) than those on CD16+ and BDCA3+ mDCs, and these two receptors were both required for the recognition of S. aureus and the subsequent activation of BDCA1+ mDCs. Finally, BDCA1+ mDC-mediated immune responses against S. aureus were dependent on MyD88 signaling pathways. These results demonstrate that human BDCA1+ mDCs represent a unique subset of mDCs that can respond to S. aureus to undergo maturation and activation and to induce Th1 and Tc1 immune responses.

Muscarinic Type 3 Receptor Induces Cytoprotective Signaling in Salivary Gland Cells through Epidermal Growth Factor Receptor Transactivation

Muscarinic type 3 receptor (M3R) plays a pivotal role in the induction of glandular fluid secretions. Although M3R is often the target of autoantibodies in Sjögrens syndrome (SjS), chemical agonists for M3R are clinically used to stimulate saliva secretion in patients with SjS. Aside from its activity in promoting glandular fluid secretion, however, it is unclear whether activation of M3R is related to other biological events in SjS. This study aimed to investigate the cytoprotective effect of chemical agonist-mediated M3R activation on apoptosis induced in human salivary gland (HSG) cells. Carbachol (CCh), a muscarinic receptor-specific agonist, abrogated tumor necrosis factor α/interferon γ-induced apoptosis through pathways involving caspase 3/7, but its cytoprotective effect was decreased by a M3R antagonist, a mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (ERK) inhibitor, a phosphatidylinositol 3-kinase/Akt inhibitor, or an epidermal growth factor receptor (EGFR) inhibitor. Ligation of M3R with CCh transactivated EGFR and phosphorylated ERK and Akt, the downstream targets of EGFR. Inhibition of intracellular calcium release or protein kinase C δ, both of which are involved in the cell signaling of M3R-mediated fluid secretion, did not affect CCh-induced ERK or Akt phosphorylation. CCh stimulated Src phosphorylation and binding to EGFR. A Src inhibitor attenuated the CCh/M3R-induced cytoprotective effect and EGFR transactivation cascades. Overall, these results indicated that CCh/M3R induced transactivation of EGFR through Src activation leading to ERK and Akt phosphorylation, which in turn suppressed caspase 3/7-mediated apoptotic signals in HSG cells. This study, for the first time, proposes that CCh-mediated M3R activation can promote not only fluid secretion but also survival of salivary gland cells in the inflammatory context of SjS.

Ginseng Berry Extract Promotes Maturation of Mouse Dendritic Cells

Ginseng extract has been shown to possess certain anti-virus, anti-tumor and immune-activating effects. However, the immunostimulatory effect of ginseng berry extract (GB) has been less well characterized. In this study, we investigated the effect of GB on the activation of mouse dendritic cells (DCs) in vitro and in vivo. GB treatment induced up-regulation of co-stimulatory molecules in bone marrow-derived DCs (BMDCs). Interestingly, GB induced a higher degree of co-stimulatory molecule up-regulation than ginseng root extract (GR) at the same concentrations. Moreover, in vivo administration of GB promoted up-regulation of CD86, MHC class I and MHC class II and production of IL-6, IL-12 and TNF-α in spleen DCs. GB also promoted the generation of Th1 and Tc1 cells. Furthermore, Toll like receptor 4 (TLR4) and myeloid differentiation primary response 88 (MyD88) signaling pathway were essential for DC activation induced by GB. In addition, GB strongly prompted the proliferation of ovalbumin (OVA)-specific CD4 and CD8 T cells. Finally, GB induced DC activation in tumor-bearing mice and the combination of OVA and GB treatment inhibited B16-OVA tumor cell growth in C57BL/6 mice. These results demonstrate that GB is a novel tumor therapeutic vaccine adjuvant by promoting DC and T cell activation.

Interleukin-7 Produced by Intestinal Epithelial Cells in Response to Citrobacter rodentium Infection Plays a Major Role in Innate Immunity against This Pathogen

ABSTRACT Interleukin-7 (IL-7) engages multiple mechanisms to overcome chronic viral infections, but the role of IL-7 in bacterial infections, especially enteric bacterial infections, remains unclear. Here we characterized the previously unexplored role of IL-7 in the innate immune response to the attaching and effacing bacterium Citrobacter rodentium. C. rodentium infection induced IL-7 production from intestinal epithelial cells (IECs). IL-7 production from IECs in response to C. rodentium was dependent on gamma interferon (IFN-γ)-producing NK1.1+ cells and IL-12. Treatment with anti-IL-7Rα antibody during C. rodentium infection resulted in a higher bacterial burden, enhanced intestinal damage, and greater weight loss and mortality than observed with the control IgG treatment. IEC-produced IL-7 was only essential for protective immunity against C. rodentium during the first 6 days after infection. An impaired bacterial clearance upon IL-7Rα blockade was associated with a significant decrease in macrophage accumulation and activation in the colon. Moreover, C. rodentium-induced expansion and activation of intestinal CD4+ lymphoid tissue inducer (LTi) cells was completely abrogated by IL-7Rα blockade. Collectively, these data demonstrate that IL-7 is produced by IECs in response to C. rodentium infection and plays a critical role in the protective immunity against this intestinal attaching and effacing bacterium.

Systemic administration of TLR3 agonist induces IL-7 expression and IL-7-dependent CXCR3 ligand production in the lung

In this study, we tested the hypothesis that systemic administration of TLR3 agonist poly I:C can enhance T cell infiltration of lung through up‐regulating IL‐7 expression. poly I:C, a synthetic analog of viral dsRNA and a TLR3 agonist, is studied extensively as vaccine adjuvant as a result of its pleotropic immune‐stimulatory effects. Here, we show that systemic poly I:C administration induces substantial IL‐7 production in the lung in a type 1 IFN‐ and IFN‐γ‐dependent fashion. Blockade of the IL‐7Rα signal with a neutralizing antibody abrogated poly I:C‐induced MCP‐1 up‐regulation, macrophage recruitment, and CXCR3 ligand expression in the lung. Conversely, administration of IL‐7 enhances these events, and it does so by enhancing T cell IFN‐γ production. We also show that the initial up‐regulation of CXCR3 ligands and infiltration of T cells in the lung are mediated by poly I:C‐induced IFN‐γ from NK cells; however, the sustained and optimal CXCR3 ligand expression and T cell infiltration require poly I:C‐induced IL‐7 and T cell‐derived IFN‐γ. In a model of multiorgan inflammation elicited by adoptive transfer of immune cells into RAG1−/− mice, we show that poly I:C enhances IL‐7 production in the lung and promotes expression of CXCR3 ligands and recruitment of IFN‐γ+ T cells in an IL‐7‐dependent fashion. Collectively, these results strongly support our hypothesis and delineate a new mechanism by which poly I:C boosts the T cell immune response in the lung by inducing local IL‐7 production, which in turn, enhances T cell‐derived IFN‐γ to promote macrophage recruitment, CXCR3 ligand expression, and T cell infiltration.