Activation of purified allogeneic CD4+ T cells by rat bone marrow-derived dendritic cells induces concurrent secretion of IFN-γ, IL-4, and IL-10

MHC/class-II-positive cells inhibit corticosterone of adrenal gland cells in experimental arthritis: a role for IL-1β, IL-18, and the inflammasome

In experimental arthritis, glucocorticoid secretion is inadequate relative to inflammation. We hypothesized that IL-1 is a key factor for inadequate glucocorticoid secretion in arthritic rats. Collagen type II—induced arthritis (CIA) in DA rats was the model to study effects of IL-1 on adrenal function. In the CIA model, an increase of intraadrenal MHCII-positive cells was observed. MHCII-positive cells or bone marrow-derived dendritic cells inhibited glucocorticoid secretion of adrenal gland cells. IL-1, but also IL-18 and the inflammasome were critical in glucocorticoid inhibition. Arthritic compared to control adrenal gland cells produced higher amounts of CXC chemokines from MHCII+ adrenal cells, particularly CINC-2, which is strongly dependent on presence of IL-1. In CIA, macrophages and/or dendritic cells inhibit glucocorticoid secretion via IL-1 in adrenal glands. These findings show that activated macrophages and/or dendritic cells inhibit glucocorticoid secretion in experimental arthritis and that IL-1β is a decisive factor.

Recombinant Sj16 from Schistosoma japonicum contains a functional N-terminal nuclear localization signal necessary for nuclear translocation in dendritic cells and interleukin-10 production

Sj16 is a Schistosoma japonicum-derived protein (16 kDa in molecular weight) that has been identified as an immune modulation molecule, but the mechanisms of modulation of immune responses are not known. In this report, we aimed to investigate the host immune regulation mechanism by recombinant Sj16 (rSj16) and thus illuminate the molecular mechanism of immune evasion by S. japonicum. The effect of rSj16 and rSj16 mutants on the biology of dendritic cells (DCs) was assessed by examining DC maturation, cytokine production, and expression of surface markers by flow cytometry and enzyme-linked immunosorbent assay. We found that rSj16 significantly stimulated interleukin (IL)-10 production and inhibited LPS-induced bone marrow-derived dendrite cell (BMDC) maturation in a dose-dependent manner. By using antibody neutralization experiments and IL-10-deficient (knockout) mice, we confirmed that the inhibitory effect of rSj16 on LPS-induced BMDCs is due to its induction of IL-10 production. To understand how rSj16 induces the production of IL-10, we analyzed the protein sequence and revealed two potential nuclear localization signals (NLS) in Sj16. The N-terminal NLS (NLS1) is both necessary and sufficient for translocation of rSj16 to the nucleus of BMDCs and is important for subsequent induction of IL-10 production and the inhibition of BMDC maturation by rSj16. The results of our study concluded that the ability of rSj16 to inhibit DC functions is IL-10 dependent which is operated by IL-10R signal pathway. This study also confirmed that NLS is an important domain associated with increased production of IL-10. Our findings will extend the current understanding on host-schistosome relationship and provide insight about bottleneck of parasitic control.

Degree of polymerization of inulin-type fructans differentially affects number of lactic acid bacteria, intestinal immune functions, and immunoglobulin A secretion in the rat cecum

This study examined the role of degree of polymerization (DP) of inulin-fructans in modulating the interaction between lactic acid bacteria and IgA cecal secretion. Rats were fed a control diet or a diet containing one of the fructans with different DP. Consuming fructans increased the cecal IgA concentrations in the order DP4 > DP8 > DP16. Cecal lactobacilli counts were higher in DP4, DP8, and DP16, whereas bifidobacteria were higher in DP8, DP16, and DP23. Cecal IgA concentrations were correlated with cecal lactobacilli counts (P < 0.01). DP4, DP8, and DP16, but not DP23, significantly increased IgA-producing plasma cells in the cecal mucosa. IFN-γ and IL-10 production in the cecal CD4(+) T cells was enhanced solely in DP4. The results show that fructans with lower DP enhance cecal IgA secretion and increase the plasma cells and suggest that the increased lactobacilli may contribute to the stimulation of cecal IgA secretion.

rSj16, a recombinant protein of Schistosoma japonicum-derived molecule, reduces severity of the complete Freund's adjuvant-induced adjuvant arthritis in rats' model

Sj16, a 16-kDa protein produced by Schistosoma japonicum, has been demonstrated to have anti-inflammatory effect. However, the possible mechanism of these phenomena has not been discovered. Here, we tried to touch it with arthritis rats' model induced by injection of complete Freund's adjuvant (CFA). A set of pathogenic characters were observed in CFA-treated rat, including local and systematic read-out, which showed the model successfully set up. After administration of rSj16 (recombinant Sj16) in vivo, paw swelling reduced significantly and in a dose-dependent manner, the level of TNF-α, IL-1β and NO decreased and IL-10 in the serum increased. In vitro, rSj16 reversed the augmented surface expression of CD80, CD86, CD54 and OX6 induced by lipopolysaccharide (LPS) in bone marrow-derived DCs (BMDCs), whereas endocytotic capacity of rSj16-treated dendritic cell (DC) was profoundly increased. IL-12p70 released from rSj16-treated BMDC was decreased but IL-10 increased. Further, following incubation with rSj16 primed BMDCs, the sensitized T cells exhibited increased production of anti-inflammatory IL-10 and IL-4 and decreased production of IL-12p70 and IFN-γ. Collectively, these results implied that rSj16 alleviated CFA-induced arthritis, and the possible mechanisms may be its interruption of maturation and function of DCs. rSj16 could be a potential therapeutic agent against rheumatoid arthritis.

Characterization of rat bone marrow dendritic cells initially primed by Trichinella spiralis antigens

Pathogen-derived products have the capacity to induce maturation of bone marrow-derived dendritic cells (BMDCs)into populations of effectors cells that polarize Th cells toward Th1 or Th2 phenotype via different mechanisms. Since those mechanisms are not entirely clear for helminths, and almost completely unknown for Trichinella spiralis(TS), we started an investigation of the effects of TS antigens (four different antigens isolated from all three life-cycle stages of parasite)on maturation of BMDCs and their potential to present TS antigens. The expression of MHC class II, costimulatory molecules CD86, CD54, IL-10 and IL-12p70 cytokine production were measured after 2 days of BMDCs cultivation with TS antigens. While parasitic antigens did not significantly alter the expression of MHC II, most of them, except crude muscle larvae antigens, up-regulated the expression of costimulatory molecules. BMDCs, primed with all TS antigens, released increased amounts of IL-10 and decreased amounts of IL-12p70. BMDCs, primed with TS antigens, induced significant proliferation of syngeneic TS sensitized lymph nodes cells and also stimulated the production of IL-4 by T cells purified from of TS infected DA rats. The results indicate that TS stimulated BMDCs leads to the polarization of the immune response towards regulatory and Th2 type.