Combined IgE neutralization and Bifidobacterium longum supplementation reduces the allergic response in models of food allergy.

IgE is central to the development of allergic diseases, and its neutralization alleviates allergic symptoms. However, most of these antibodies are based on IgG1, which is associated with an increased risk of fragment crystallizable-mediated side effects. Moreover, omalizumab, an anti-IgE antibody approved for therapeutic use, has limited benefits for patients with high IgE levels. Here, we assess a fusion protein with extracellular domain of high affinity IgE receptor, FcεRIα, linked to a IgD/IgG4 hybrid Fc domain we term IgETRAP, to reduce the risk of IgG1 Fc-mediated side effects. IgETRAP shows enhanced IgE binding affinity compared to omalizumab. We also see an enhanced therapeutic effect of IgETRAP in food allergy models when combined with Bifidobacterium longum, which results in mast cell number and free IgE levels. The combination of IgETRAP and B. longum may therefore represent a potent treatment for allergic patients with high IgE levels.

IL-12p40 Homodimer Ameliorates Experimental Autoimmune Arthritis.

IL-23 is the key cytokine that induces the expansion of Th17 cells. It is composed of p19 and p40 subunits of IL-12. The p40 subunit binds competitively to the receptor of IL-23 and blocks its activity. Our aim was to assess the preventive and therapeutic effect of the IL-12p40 homodimer (p40)2 subunit in autoimmune arthritis animal models. In the current study, using IL-1R antagonist-knockout mice and a collagen-induced arthritis model, we investigated the suppressive effect of (p40)2 on inflammatory arthritis. We demonstrated that the recombinant adenovirus-expressing mouse (p40)2 model prevented the development of arthritis when given before the onset of arthritis. It also decreased the arthritis index and joint erosions in the mouse model if transferred after arthritis was established. (p40)2 inhibited the production of inflammatory cytokines and Ag-specific T cell proliferation. It also induced CD4(+)CD25(+)Foxp3 regulatory T (Treg) cells in vitro and in vivo, whereas the generation of retinoic acid receptor-related organ receptor γt and Th17 cells was suppressed. The induction of Treg cells and the suppression of Th17 cells were mediated via activated STAT5 and suppressed STAT3. Our data suggest that (p40)2 suppressed inflammatory arthritis successfully. This could be a useful therapeutic approach in autoimmune arthritis to regulate the Th17/Treg balance and IL-23 signaling.

Safety and immunogenicity of therapeutic DNA vaccine with antiviral drug in chronic HBV patients and its immunogenicity in mice.

BACKGROUND & AIMS: Here, we evaluated the safety and immunogenicity of hepatitis B virus (HBV) DNA vaccine, HB-110, in mice and Korean patients with chronic hepatitis B (CHB) undergoing adefovir dipivoxil (ADV) treatment. METHODS: For animal study, mice (BALB/c or HBV transgenic) were immunized with mHB-110, and T-cell and antibody responses were evaluated. For clinical study, 27 patients randomly received either ADV alone or ADV in combination with HB-110. Liver function tests, serum HBV DNA levels and the presence of HBeAg/anti-HBe were analysed. T-cell responses were estimated by ELISPOT and FACS analysis. RESULTS: mHB-110 induced higher T-cell and antibody responses than mHB-100 in mice. No adverse effects were observed by HB-110 cotreated with ADV. HBV-specific T-cell responses were induced in a portion of patients in medium to high dose of HB-110. Interestingly, HB-110 exhibited positive effects on ALT normalization and maintenance of HBeAg seroconversion. One patient, who received high dose of HB-110 exhibited HBeAg seroconversion during vaccination, which correlated with vaccine-induced T-cell responses without ALT elevation. CONCLUSIONS: HB-110 was safe and tolerable in CHB patients. In contrast to results in animal models, HB-110 in Korean patients exhibited weaker capability of inducing HBV-specific T-cell responses and HBeAg seroconversion than HB-100 in Caucasian patients. As Asian patients, who are generally infected via vertical transmission, appeared to have higher level of immune tolerance than Caucasian, novel approaches for breaking immune tolerance rather than enhancing immunogenicity may be more urgently demanded to develop effective therapeutic HBV DNA vaccines.

Protective effects of Fc-fused PD-L1 on two different animal models of colitis.

OBJECTIVE: Programmed death-ligand 1 (PD-L1) has been shown to negatively regulate immune responses via its interaction with PD-1 receptor. In this study, we investigated the effects of PD-L1-Fc treatment on intestinal inflammation using two murine models of inflammatory colitis induced by dextran sulfate sodium (DSS) and T-cell transfer. DESIGN: The anti-colitis effect of adenovirus expressing Fc-conjugated PD-L1 (Ad/PD-L1-Fc) and recombinant PD-L1-Fc protein was evaluated in DSS-treated wild-type and Rag-1 knockout (KO) mice. We examined differentiation of T-helper cells, frequency of innate immune cells, and cytokine production by dendritic cells (DCs) in the colon from DSS-treated mice after PD-L1-Fc administration. In Rag-1 KO mice reconstituted with CD4 CD45RB(high) T cells, we assessed the treatment effect of PD-L1-Fc protein on the development of colitis. RESULTS: Administration of Ad/PD-L1-Fc significantly ameliorated DSS-induced colitis, which was accompanied by diminished frequency of interleukin (IL)-17A-producing CD4 T cells and increased interferon-γ-producing CD4 T cells in the colon of DSS-fed mice. The anti-colitic effect of PD-L1-Fc treatment was also observed in DSS-treated Rag-1 KO mice, indicating lymphoid cell independency. PD-L1-Fc modulated cytokine production by colonic DCs and the effect was dependent on PD-1 expression. Furthermore, PD-L1-Fc protein could significantly reduce the severity of colitis in CD4 CD45RB(high) T-cell-transferred Rag-1 KO mice. CONCLUSIONS: Based on the protective effect of PD-L1-Fc against DSS-induced and T-cell-induced colitis, our results suggest that PD-1-mediated inhibitory signals have a crucial role in limiting the development of colonic inflammation. This implicates that PD-L1-Fc may provide a novel therapeutic approach to treat inflammatory bowel disease.

In vivo action of IL-27: reciprocal regulation of Th17 and Treg cells in collagen-induced arthritis.

Interleukin (IL)-27 is a novel cytokine of the IL-6/IL-12 family that has been reported to be involved in the pathogenesis of autoimmune diseases and has a pivotal role as both a pro- and anti-inflammatory cytokine. We investigated the in vivo effects of IL-27 on arthritis severity in a murine collagen-induced arthritis (CIA) model and its mechanism of action regarding control of regulatory T (Tregs) and IL-17-producing T helper 17 (Th17) cells. IL-27-Fc-treated CIA mice showed a lower severity of arthritis. IL-17 expression in the spleens was significantly decreased in IL-27-Fc-treated CIA mice compared with that in the CIA model. The Th17 population was decreased in the spleens of IL-27-Fc-treated CIA mice, whereas the CD4(+)CD25(+)Foxp3(+) Treg population increased. In vitro studies revealed that IL-27 inhibited IL-17 production in murine CD4(+) T cells, and the effect was associated with retinoic acid-related orphan receptor γT and signal transducer and activator of transcription 3 inhibition. In contrast, fluorescein isothiocyanate-labeled forkhead box P3 (Foxp3) and IL-10 were profoundly augmented by IL-27 treatment. Regarding the suppressive capacity of Treg cells, the proportions of CTLA-4(+) (cytotoxic T-lymphocyte antigen 4), PD-1(+) (programmed cell death protein 1) and GITR(+) (glucocorticoid-induced tumor necrosis factor receptor) Tregs increased in the spleens of IL-27-Fc-treated CIA mice. Furthermore, in vitro differentiated Treg cells with IL-27 exerted a more suppressive capacity on T-cell proliferation. We found that IL-27 acts as a reciprocal regulator of the Th17 and Treg populations in CD4(+) cells isolated from healthy human peripheral blood mononuclear cells (PBMCs), as well as from humans with rheumatoid arthritis (RA) PBMCs. Our study suggests that IL-27 has the potential to ameliorate overwhelming inflammation in patients with RA through a reciprocal regulation of Th17 and Treg cells.

STAT3 and NF-kappaB signal pathway is required for IL-23-mediated IL-17 production in spontaneous arthritis animal model IL-1 receptor antagonist-deficient mice.

IL-23 is a heterodimeric cytokine composed of a p19 subunit and the p40 subunit of IL-12. IL-23 has proinflammatory activity, inducing IL-17 secretion from activated CD4(+) T cells and stimulating the proliferation of memory CD4(+) T cells. We investigated the pathogenic role of IL-23 in CD4(+) T cells in mice lacking the IL-1R antagonist (IL-1Ra(-/-)), an animal model of spontaneous arthritis. IL-23 was strongly expressed in the inflamed joints of IL-1Ra(-/-) mice. Recombinant adenovirus expressing mouse IL-23 (rAd/mIL-23) significantly accelerated this joint inflammation and joint destruction. IL-1beta further increased the production of IL-23, which induced IL-17 production and OX40 expression in splenic CD4(+) T cells of IL-1Ra(-/-) mice. Blocking IL-23 with anti-p19 Ab abolished the IL-17 production induced by IL-1 in splenocyte cultures. The process of IL-23-induced IL-17 production in CD4(+) T cells was mediated via the activation of Jak2, PI3K/Akt, STAT3, and NF-kappaB, whereas p38 MAPK and AP-1 did not participate in the process. Our data suggest that IL-23 is a link between IL-1 and IL-17. IL-23 seems to be a central proinflammatory cytokine in the pathogenesis of this IL-1Ra(-/-) model of spontaneous arthritis. Its intracellular signaling pathway could be useful therapeutic targets in the treatment of autoimmune arthritis.