IL-10 control of dendritic cells in the skin

Interleukin-10 (IL-10) is a potent immunomodulatory cytokine, whose cellular targets have not yet been precisely identified. Mice bearing a dendritic cell (DC)-specific defect in the IL-10 receptor mice exhibit exaggerated T-cell reactivation in the skin, highlighting a key function of DCs in the maintenance of local immune homeostasis

β-Catenin Signaling Drives Differentiation and Proinflammatory Function of IRF8-Dependent Dendritic Cells.

β-Catenin signaling has recently been tied to the emergence of tolerogenic dendritic cells (DCs). In this article, we demonstrate a novel role for β-catenin in directing DC subset development through IFN regulatory factor 8 (IRF8) activation. We found that splenic DC precursors express β-catenin, and DCs from mice with CD11c-specific constitutive β-catenin activation upregulated IRF8 through targeting of the Irf8 promoter, leading to in vivo expansion of IRF8-dependent CD8α(+), plasmacytoid, and CD103(+)CD11b(-) DCs. β-Catenin-stabilized CD8α(+) DCs secreted elevated IL-12 upon in vitro microbial stimulation, and pharmacological β-catenin inhibition blocked this response in wild-type cells. Upon infections with Toxoplasma gondii and vaccinia virus, mice with stabilized DC β-catenin displayed abnormally high Th1 and CD8(+) T lymphocyte responses, respectively. Collectively, these results reveal a novel and unexpected function for β-catenin in programming DC differentiation toward subsets that orchestrate proinflammatory immunity to infection

Dendritic cell-specific deletion of β-catenin results in fewer regulatory T-cells without exacerbating autoimmune collagen-induced arthritis

Dendritic cells (DCs) are professional antigen presenting cells that have the dual ability to stimulate immunity and maintain tolerance. However, the signalling pathways mediating tolerogenic DC function in vivo remain largely unknown. The β-catenin pathway has been suggested to promote a regulatory DC phenotype. The aim of this study was to unravel the role of β-catenin signalling to control DC function in the autoimmune collagen-induced arthritis model (CIA). Deletion of β-catenin specifically in DCs was achieved by crossing conditional knockout mice with a CD11c-Cre transgen

Tnfaip3 expression in pulmonary conventional type 1 Langerin-expressing dendritic cells regulates T helper 2-mediated airway inflammation in mice

Background: Conventional type 1 dendritic cells (cDC1s) control anti-viral and anti-tumor immunity by inducing antigen-specific cytotoxic CD8+ T-cell responses. Controversy exists whether cDC1s also control CD4+ T helper 2 (Th2) cell responses, since suppressive and activating roles have been reported. DC activation status, controlled by the transcription factor NF-κB, might determine the precise outcome of Th-cell differentiation upon encounter with cDC1s. To investigate the role of activated cDC1s in Th2-driven immune responses, pulmonary cDC1s were activated by targeted deletion of A20/Tnfaip3, a negative regulator of NF-κB signaling. Methods: To target pulmonary cDC1s, Cd207 (Langerin)-mediated excision of A20/Tnfaip3 was used, generating Tnfaip3fl/flxCd207+/cre (Tnfaip3Lg-KO) mice. Mice were exposed to house dust mite (HDM) to provoke Th2-mediated immune responses. Results: Mice harboring Tnfaip3-deficient cDC1s did not develop Th2-driven eosinophilic airway inflammation upon HDM exposure, but rather showed elevated numbers of IFNγ-expressing CD8+ T cells. In addition, Tnfaip3Lg-KO mice harbored increased numbers of IL-12–expressing cDC1s and elevated PD-L1 expression in all pulmonary DC subsets. Blocking either IL-12 or IFNγ in Tnfaip3Lg-KO mice restored Th2 responses, whereas administration of recombinant IFNγ during HDM sensitization in C57Bl/6 mice blocked Th2 development. Conclusions: These findings indicate that the activation status of cDC1s, shown by their specific expression of co-inhibitory molecules and cytokines, critically contributes to the development of Th2 cell–mediated disorders, most likely by influencing IFNγ production in CD8+ T cells

Absolute dimensions of solar-type eclipsing binaries

We present complete uvby light curves of 9 recently discovered eclipsing binaries having late F, G, and K type components within or near the main-sequence band. They are the first results from a long term program carried out since 1994 at the Strömgren Automatic Telescope at ESO, La Silla. The aim is to provide the accurate absolute dimensions for solar-type stars needed for critical tests of the corresponding theoretical models. A serious dilemma appears to be present in the comparison of predictions from current stellar models with fundamental properties of known $0.7{-}1.1 M_{\odot}$ eclipsing binaries (Popper [CITE], Clausen et al. [CITE]). Spectroscopic observations of the 9 eclipsing binaries are either available or are being obtained, and detailed analyses of the individual systems will be published in a series of subsequent papers. The light curves were obtained as part of a systematic search for new eclipsing systems among a large sample of (mostly) spectroscopic binaries. Catalogues of the extensive uvby and β photometry from this search will be published separately