Search results for "dendritic cell"

2020

Dendritic cells (DC) play a key role in the adaptive immune response due to their ability to present antigens and stimulate naive T cells. Many bacteria and viruses can efficiently target DC, resulting in impairment of their immunostimulatory function or elimination. Hence, the DC compartment requires replenishment following infection to ensure continued operational readiness of the adaptive immune system. Here, we investigated the molecular and cellular mechanisms of inflammation-induced DC generation. We found that infection with viral and bacterial pathogens as well as Toll-like receptor 9 (TLR9) ligation with CpG-oligodeoxynucleotide (CpG-ODN) expanded an erythropoietin (EPO)-dependent …

Targeting myeloid cells in the tumor sustaining microenvironment.

2017

Myeloid cells are the most abundant cells in the tumor microenvironment (TME). The tumor recruits and modulates endogenous myeloid cells to tumor-associated macrophages (TAM), dendritic cells (DC), myeloid-derived suppressor cells (MDSC) and neutrophils (TAN), to sustain an immunosuppressive environment. Pathologically overexpressed mediators produced by cancer cells like granulocyte-macrophage colony-stimulating- and vascular endothelial growth factor induce myelopoiesis in the bone marrow. Excess of myeloid cells in the blood, periphery and tumor has been associated with tumor burden. In cancer, myeloid cells are kept at an immature state of differentiation to be diverted to an immunosupp…

Nitration of Wheat Amylase Trypsin Inhibitors Increases Their Innate and Adaptive Immunostimulatory Potential

2018

Amylase trypsin inhibitors (ATI) can be found in all gluten containing cereals and are, therefore, ingredient of basic foods like bread or pasta. In the gut ATI can mediate innate immunity via activation of the Toll-like receptor 4 (TLR4) on immune cells residing in the lamina propria, promoting intestinal, as well as extra-intestinal, inflammation. Inflammatory conditions can induce formation of peroxynitrite (ONOO-) and, thereby, endogenous protein nitration in the body. Moreover, air pollutants like ozone (O3) and nitrogen dioxide (NO2) can cause exogenous protein nitration in the environment. Both reaction pathways may lead to the nitration of ATI. To investigate if and how nitration mo…

Peripherally Induced Regulatory T Cells: Recruited Protectors of the Central Nervous System against Autoimmune Neuroinflammation

2017

Defects in regulatory T cells (Treg cells) aggravate multiple sclerosis (MS) after its onset and the absence of Treg cell functions can also exacerbate the course of disease in an animal model of MS. However, autoimmune neuroinflammation in many MS models can be acutely provoked in healthy animals leading to an activation of encephalitogenic T cells despite the normal induction of immune tolerance in the thymus including thymically-produced (t)Treg cells. In contrast, neuroinflammation can be ameliorated or even completely prevented by the antigen-specific Treg cells formed extrathymically in the peripheral immune system (pTreg cells) during tolerogenic responses to relevant neuronal antige…

Editorial: Current concepts of cellular and biological drugs to modulate regulatory T cell activity in the clinic

2016

The Editorial on the Research Topic Current Concepts of Cellular and Biological Drugs to Modulate Regulatory T Cell Activity in the Clinic Regulatory T (Treg) cells are essential for the maintenance of peripheral tolerance and prevent the development of autoimmunity and allergy. While on the one hand being indispensable for the perpetuation of tolerance to harmless antigens or self-antigens, Treg cells contribute to cancer pathogenesis and progression (1). Hence, the potential to treat a multitude of different human diseases by pharmacological modulation of Treg cells is enormous. Consequently, this T cell population is in the focus of biomedical research and development. Currently, isolate…

The Ontogeny of Monocyte Subsets

2019

Classical and non-classical monocytes, and the macrophages and monocyte-derived dendritic cells they produce, play key roles in host defense against pathogens, immune regulation, tissue repair and many other processes throughout the body. Recent studies have revealed previously unappreciated heterogeneity among monocytes that may explain this functional diversity, but our understanding of mechanisms controlling the functional programming of distinct monocyte subsets remains incomplete. Resolving monocyte heterogeneity and understanding how their functional identity is determined holds great promise for therapeutic immune modulation. In this review, we examine how monocyte origins and develo…

Insufficient generation of Th17 cells in IL-23p19-deficient BALB/c mice protects against progressive cutaneous leishmaniasis

2017

Healing of leishmaniasis-a parasitic skin disease-is associated with high levels of secreted interferon (IFN)γ and IL-12 in resistant C57BL/6 mice and humans. Susceptible BALB/c mice predominantly react with a Th17/Th2/Treg-related immune response and finally succumb to infection. Previously, we showed that BALB/c IL-17A-/- mice are protected against Leishmania (L.) major infections, indicating that IL-17A-predominantly produced by Th17 cells-plays an important role for disease outcome. We now investigated DC-derived cytokines and finally identified IL-23p19 as key cytokine responsible for induction of Leishmania-specific Th17 cells that play an important role for progressive disease in sus…

Leukemia-associated activating mutation of Flt3 expands dendritic cells and alters T cell responses

2016

Lau et al. show that the FLT3-ITD mutation directly affects dendritic cell development in preleukemic mice, indirectly modulating T cell homeostasis and supporting the expansion of regulatory T cells.

Tumor-derived immuno-modulators induce overlapping pro-tolerogenic gene expression signatures in human dendritic cells.

2016

Immature dendritic cells (iDCs) and tolerogenic DCs are essential for the induction and maintenance of peripheral tolerance. Tumors produce immuno-modulatory factors which imprint a pro-tolerogenic, maturation-resistant state in DCs. Here we asked for common markers of differentially tolerized human monocyte-derived DC populations. For this, PBMC-derived monocytes were differentiated to DCs in the presence of established immuno-modulators as released by tumors (IL-6, IL-10, TGF-β, glucocorticoid [GC], prostaglandin E2 [PGE2]). Most unstimulated pro-tolerogenic DC populations commonly over-expressed some tolerance-associated markers (ILT-4, IL-10, HO-1) as compared with iDCs. These markers m…

Immunogenicity of a Fully Synthetic MUC1 Glycopeptide Antitumor Vaccine Enhanced by Poly(I:C) as a TLR3-Activating Adjuvant.

2017

Fully synthetic MUC1 glycopeptide antitumor vaccines have a precisely specified structure and induce a targeted immune response without suppression of the immune response when using an immunogenic carrier protein. However, tumor-associated aberrantly glycosylated MUC1 glycopeptides are endogenous structures, “self-antigens”, that exhibit only low immunogenicity. To overcome this obstacle, a fully synthetic MUC1 glycopeptide antitumor vaccine was combined with poly(inosinic acid:cytidylic acid), poly(I:C), as a structurally defined Toll-like receptor 3 (TLR3)-activating adjuvant. This vaccine preparation elicited extraordinary titers of IgG antibodies which strongly bound human breast cancer…