The Dichotomous Pattern of IL-12R and IL-23R Expression Elucidates the Role of IL-12 and IL-23 in Inflammation

IL-12 and IL-23 cytokines respectively drive Th1 and Th17 type responses. Yet, little is known regarding the biology of these receptors. As the IL-12 and IL-23 receptors share a common subunit, it has been assumed that these receptors are co-expressed. Surprisingly, we find that the expression of each of these receptors is restricted to specific cell types, in both mouse and human. Indeed, although IL-12Rβ2 is expressed by NK cells and a subset of γδ T cells, the expression of IL-23R is restricted to specific T cell subsets, a small number of B cells and innate lymphoid cells. By exploiting an IL-12- and IL-23-dependent mouse model of innate inflammation, we demonstrate an intricate interplay between IL-12Rβ2 NK cells and IL-23R innate lymphoid cells with respectively dominant roles in the regulation of systemic versus local inflammatory responses. Together, these findings support an unforeseen lineage-specific dichotomy in the in vivo role of both the IL-12 and IL-23 pathways in pathological inflammatory states, which may allow more accurate dissection of the roles of these receptors in chronic inflammatory diseases in humans

High doses of CpG oligodeoxynucleotides stimulate a tolerogenic TLR9–TRIF pathway

CpG-rich oligodeoxynucleotides activate the immune system, leading to innate and acquired immune responses. The immune-stimulatory effects of CpG-rich oligodeoxynucleotides are being exploited as a therapeutic approach. Here we show that at high doses, CpG-rich oligodeoxynucleotides promote an opposite, tolerogenic response in mouse plasmacytoid dendritic cells in vivo and in a human in vitro model. Unveiling a previously undescribed role for TRIF and TRAF6 proteins in Toll-like receptor 9 (TLR9) signalling, we demonstrate that physical association of TLR9, TRIF and TRAF6 leads to activation of noncanonical NF-κB signalling and the induction of IRF3- and TGF-β-dependent immune-suppressive tryptophan catabolism. In vivo, the TLR9-TRIF circuit--but not MyD88 signalling--was required for CpG protection against allergic inflammation. Our findings may be relevant to an increased understanding of the complexity of Toll-like receptor signalling and optimal exploitation of CpG-rich oligodeoxynucleotides as immune modulators

Analysis of the activation profile of dendritic cells derived from the bone marrow of interleukin-12/interleukin-23-deficient mice

We have previously shown that macrophages from interleukin (IL)-12p40 gene knockout (IL-12/IL-23(−/−)) mice have a bias towards the M2 activation profile, spontaneously secreting large quantities of transforming growth factor-β1 (TGF-β1) and producing low levels of nitric oxide (NO) in response to lipopolysaccharide (LPS) and interferon-γ (IFN-γ). To verify whether the activation profile of dendritic cells (DCs) is also influenced by the absence of IL-12/IL-23, bone marrow-derived DCs from IL-12/IL-23(−/−) and C57BL/6 mice were evaluated. At first we noticed that ≈ 50% of the C57BL/6 DCs were dead after LPS-induced maturation, whereas the mortality of IL-12/IL-23(−/−) DCs was < 10%, a protective effect that diminished when recombinant IL-12 (rIL-12) was added during maturation. Similarly to macrophages, mature IL-12/IL-23(−/−) DCs (mDCs) produced higher levels of TGF-β1 and lower levels of NO than C57BL/6 mDCs. NO release was IFN-γ-dependent, as evidenced by the poor response of IFN-γ(−/−) and IL-12/IL-23(−/−)IFN-γ(−/−) mDCs. Nevertheless, IFN-γ deficiency was not the sole reason for the weak NO response observed in the absence of IL-12/IL-23. The high level of TGF-β1 secretion by IL-12/IL-23(−/−) mDCs could explain why exogenous IFN-γ partially restored the NO production of IFN-γ(−/−) mDCs, while IL-12/IL-23(−/−) IFN-γ(−/−) mDCs remained unresponsive. We also showed that CD4(+) T-cell proliferation was inhibited by C57BL/6 mDCs, but not by IL-12/IL-23(−/−) mDCs. IFN-γ and NO appear to mediate this antiproliferative effect because this effect was not observed in the presence of mDCs from IFN-γ(−/−) or IL-12/IL-23(−/−) IFN-γ(−/−) mice and it was attenuated by aminoguanidine. We conclude that the presence of IL-12/IL-23 during LPS-induced maturation influences the activation profile of DCs by a mechanism that is, only in part, IFN-γ dependent

Assessment of TILs, IDO-1, and PD-L1 in resected non-small cell lung cancer: an immunohistochemical study with clinicopathological and prognostic implications

Several cancers, especially non-small cell lung cancer (NSCLC), are able to escape the immunosurveillance of tumor-infiltrating lymphocytes (TILs); among the molecules involved, the indoleamine 2,3-dioxygenase 1 (IDO-1) and the programmed cell death ligand-1 (PD-L1) play a crucial role. These aspects are of great interest in the current immunotherapeutic era, therefore the current study analyses the TILs, IDO-1, and PD-L1 interactions and their correlations with clinicopathological parameters and prognosis in NSCLC. One hundred ninety-three NSCLC surgical specimens, formalin-fixed, and paraffin-embedded were assessed for TILs density, TILs localization, IDO-1 (clone 4.16H1), and PD-L1 (clone E1L3N) immunohistochemical expressions. This data was correlated with clinicopathological parameters, disease free, and overall survivals. IDO-1 and PD-L1 high expressions were related to the solid pattern of adenocarcinomas (respectively p = 0.036 and p = 0.026); high PD-L1 expression was correlated with squamous histotype (p = 0.048). IDO-1 overexpression correlated with former smokers (p = 0.041), higher adenocarcinoma stages (p = 0.039), and with both higher TILs density and PD-L1 expression (respectively p = 0.025 and p = 0.0003). A better prognosis was associated with TILs intratumoral or mixed localizations (p = 0.029). TILs localization affects NSCLC prognosis; the higher expression of IDO-1 and PD-L1 in poorly differentiated and more aggressive lung adenocarcinomas, as well as the correlation between high PD-L1 expression and squamous cell histotype, confirm the more efficient immunoescaping of these NSCLC subgroups

Assessment of TILs, IDO-1, and PD-L1 in resected non-small cell lung cancer: an immunohistochemical study with clinicopathological and prognostic implications

Several cancers, especially non-small cell lung cancer (NSCLC), are able to escape the immunosurveillance of tumor-infiltrating lymphocytes (TILs); among the molecules involved, the indoleamine 2,3-dioxygenase 1 (IDO-1) and the programmed cell death ligand-1 (PD-L1) play a crucial role. These aspects are of great interest in the current immunotherapeutic era, therefore the current study analyses the TILs, IDO-1, and PD-L1 interactions and their correlations with clinicopathological parameters and prognosis in NSCLC. One hundred ninety-three NSCLC surgical specimens, formalin-fixed, and paraffin-embedded were assessed for TILs density, TILs localization, IDO-1 (clone 4.16H1), and PD-L1 (clone E1L3N) immunohistochemical expressions. This data was correlated with clinicopathological parameters, disease free, and overall survivals. IDO-1 and PD-L1 high expressions were related to the solid pattern of adenocarcinomas (respectively p = 0.036 and p = 0.026); high PD-L1 expression was correlated with squamous histotype (p = 0.048). IDO-1 overexpression correlated with former smokers (p = 0.041), higher adenocarcinoma stages (p = 0.039), and with both higher TILs density and PD-L1 expression (respectively p = 0.025 and p = 0.0003). A better prognosis was associated with TILs intratumoral or mixed localizations (p = 0.029). TILs localization affects NSCLC prognosis; the higher expression of IDO-1 and PD-L1 in poorly differentiated and more aggressive lung adenocarcinomas, as well as the correlation between high PD-L1 expression and squamous cell histotype, confirm the more efficient immunoescaping of these NSCLC subgroups

Indoleamine 2,3-dioxygenase is a signaling protein in long-term tolerance by dendritic cells

Regulation of tryptophan metabolism by indoleamine 2,3-dioxygenase (IDO) in dendritic cells (DCs) is a highly versatile modulator of immunity. In inflammation, interferon-\u3b3 is the main inducer of IDO for the prevention of hyperinflammatory responses, yet IDO is also responsible for self-tolerance effects in the longer term. Here we show that treatment of mouse plasmacytoid DCs (pDCs) with transforming growth factor-\u3b2 (TGF-\u3b2) conferred regulatory effects on IDO that were mechanistically separable from its enzymic activity. We found that IDO was involved in intracellular signaling events responsible for the self-amplification and maintenance of a stably regulatory phenotype in pDCs. Thus, IDO has a tonic, nonenzymic function that contributes to TGF-\u3b2-driven tolerance in noninflammatory context