A potential concern with bacteriophage (phage) therapeutics is a host-versus-phage response in which the immune system may neutralize or destroy phage particles and thus impair therapeutic efficacy, ...or a strong inflammatory response to repeated phage exposure might endanger the patient. Current literature is discrepant with regard to the nature and magnitude of innate and adaptive immune response to phages. The purpose of this work was to study the potential effects of
phage K on the activation of human monocyte-derived dendritic cells. Since phage K acquired from ATCC was isolated around 90 years ago, we first tested its activity against a panel of 36 diverse
clinical isolates from military patients and found that it was lytic against 30/36 (83%) of strains. Human monocyte-derived dendritic cells were used to test for an in vitro phage-specific inflammatory response. Repeated experiments demonstrated that phage K had little impact on the expression of pro- and anti-inflammatory cytokines, or on MHC-I/II and CD80/CD86 protein expression. Given that dendritic cells are potent antigen-presenting cells and messengers between the innate and the adaptive immune systems, our results suggest that phage K does not independently affect cellular immunity or has a very limited impact on it.
Agonists of Toll-like receptors (TLRs) are potent activators of the innate immune system and hold promise as vaccine adjuvant and for anticancer immunotherapy. Unfortunately, in soluble form they ...readily enter systemic circulation and cause systemic inflammatory toxicity. Here we demonstrate that by covalent ligation of a small-molecule imidazoquinoline-based TLR7/8 agonist to 50-nm-sized degradable polymeric nanogels the potency of the agonist to activate TLR7/8 in in vitro cultured dendritic cells is largely retained. Importantly, imidazoquinoline-ligated nanogels focused the in vivo immune activation on the draining lymph nodes while dramatically reducing systemic inflammation. Mechanistic studies revealed a prevalent passive diffusion of the nanogels to the draining lymph node. Moreover, immunization studies in mice have shown that relative to soluble TLR7/8 agonist, imidazoquinoline-ligated nanogels induce superior antibody and T-cell responses against a tuberculosis antigen. This approach opens possibilities to enhance the therapeutic benefit of small-molecule TLR agonist for a variety of applications.
Myeloid cells, especially mononuclear phagocytes, which include monocytes, macrophages and dendritic cells (DC), play vital roles in innate immunity, and in the initiation and maintenance of adaptive ...immunity. While T cell-associated activation pathways and cytokines have been identified and evaluated in inflammatory bowel disease (IBD) patients (Neurath, Nat Rev Gastroenterol Hepatol 14:269-78, 1989), the role of mononuclear phagocytes are less understood. Recent reports support the crucial role of DC subsets in the development of acute colitis models (Arimura et al., Mucosal Immunol 10:957-70, 2017), and suggest they may contribute to the pathogenesis of ulcerative colitis (UC) by inducing Th1/Th2/Th17 responses (Matsuno et al., Inflamm Bowel Dis 23:1524-34, 2017).
We performed in silico analysis and evaluated the enrichment of immune cells, with a focus on mononuclear phagocytes in IBD patient colonic biopsies. Samples were from different gut locations, with different levels of disease severity, and with treatment response to current therapies. We observe enrichment of monocytes, M1 macrophages, activated DCs (aDCs) and plasmacytoid dendritic cells (pDCs) in inflamed tissues from various gut locations. This enrichment correlates with disease severity. Additionally, the same mononuclear phagocytes subsets are among the top enriched cell types in both infliximab and vedolizumab treatment non-responder samples. We further investigated the enrichment of selected DC and monocyte subsets based on gene signatures derived from a DC- and monocyte-focused single cell RNA-seq (scRNA-seq) study (Villani et al., Science 356:eaah4573, 2017), and verified enrichment in both inflamed tissues and those with treatment resistance. Moreover, we validated an increased mononuclear phagocyte subset abundance in a Dextran Sulphate Sodium (DSS) induced colitis model in C57Bl/6 mice representative of chronic inflammation.
We conducted an extensive analysis of immune cell populations in IBD patient colonic samples and identified enriched subsets of monocytes, macrophages and dendritic cells in inflamed tissues. Understanding how they interact with other immune cells and other cells in the colonic microenvironment such as epithelial and stromal cells will help us to delineate disease pathogenesis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Systemic murine conventional dendritic cells (cDCs) with inherent tolerogenic functions are distinguished by their high expression of B and T lymphocyte-associated/attenuator (BTLA) and reside in ...peripheral lymphoid organs.Tolerogenic murine cDCs induce peripheral regulatory CD4+ T (pTreg) cells with crucial functions in mitigating autoimmunity.Tolerogenic murine cDCs undergo an acute tumor necrosis factor α (TNFα)-mediated cell death, resulting in the loss of tolerogenic functionality under proinflammatory conditions.The acute cell death of tolerogenic murine cDCs prevents the de novo induction of tolerance to peripheral antigens until they are replenished from their bone marrow precursors.
Tolerogenic cDCs play a regulatory role in promoting and maintaining tolerance against self-antigens by inducing pTreg cell differentiation in the steady state, a process that is crucial for the maintenance of homeostasis. Over recent years there has been much interest in advancing our understanding and characterization of tolerogenic cDCs and how they respond to various immune conditions, which may allow the design of improved candidate immunotherapies and vaccines.
In contrast to conventional dendritic cells (cDCs) that are constantly exposed to microbial signals at anatomical barriers, cDCs in systemic lymphoid organs are sheltered from proinflammatory stimulation in the steady state but respond to inflammatory signals by gaining specific immune functions in a process referred to as maturation. Recent findings show that, during maturation, a population of systemic tolerogenic cDCs undergoes an acute tumor necrosis factor α (TNFα)-mediated cell death, resulting in the loss of tolerance-inducing capacity. This tolerogenic cDC population is restored upon return to the homeostatic baseline. We propose that such a dynamic reshaping of cDC populations becomes the foundation of a novel framework for maintaining tolerance at the steady state while being conducive to unhampered initiation of immune responses under proinflammatory conditions.
Atopic dermatitis (AD) is a prevalent inflammatory skin disease with a complex pathogenesis involving immune cell and epidermal abnormalities. Despite whole tissue biopsy studies that have advanced ...the mechanistic understanding of AD, single cell–based molecular alterations are largely unknown.
Our aims were to construct a detailed, high-resolution atlas of cell populations and assess variability in cell composition and cell-specific gene expression in the skin of patients with AD versus in controls.
We performed single-cell RNA sequencing on skin biopsy specimens from 5 patients with AD (4 lesional samples and 5 nonlesional samples) and 7 healthy control subjects, using 10× Genomics.
We created transcriptomic profiles for 39,042 AD (lesional and nonlesional) and healthy skin cells. Fibroblasts demonstrated a novel COL6A5+COL18A1+ subpopulation that was unique to lesional AD and expressed CCL2 and CCL19 cytokines. A corresponding LAMP3+ dendritic cell (DC) population that expressed the CCL19 receptor CCR7 was also unique to AD lesions, illustrating a potential role for fibroblast signaling to immune cells. The lesional AD samples were characterized by expansion of inflammatory DCs (CD1A+FCER1A+) and tissue-resident memory T cells (CD69+CD103+). The frequencies of type 2 (IL13+)/type 22 (IL22+) T cells were higher than those of type 1 (IFNG+) in lesional AD, whereas this ratio was slightly diminished in nonlesional AD and further diminished in controls.
AD lesions were characterized by expanded type 2/type 22 T cells and inflammatory DCs, and by a unique inflammatory fibroblast that may interact with immune cells to regulate lymphoid cell organization and type 2 inflammation.
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Macrophages and dendritic cells (DCs) are key components of cellular immunity and are thought to originate and renew from hematopoietic stem cells (HSCs). However, some macrophages develop in the ...embryo before the appearance of definitive HSCs. We thus reinvestigated macrophage development. We found that the transcription factor Myb was required for development of HSCs and all CD11b high monocytes and macrophages, but was dispensable for yolk sac (YS) macrophages and for the development of YS-derived F4/80 bright macrophages in several tissues, such as liver Kupffer cells, epidermal Langerhans cells, and microglia— cell populations that all can persist in adult mice independently of HSCs. These results define a lineage of tissue macrophages that derive from the YS and are genetically distinct from HSC progeny.
•NPs can be utilized for antigen delivery into DCs and the improvement of DC vaccines.•Antigen delivery by NPs can reduce the disadvantages of DC vaccines.•NP-mediated antigen delivery can be ...considered a new promising approach to administer DC vaccines.
Dendritic cell (DC)-based cancer immunotherapy has shown impressive outcomes, including the development of the first FDA-approved anti-cancer vaccine. However, the clinical application of DC-based cancer immunotherapy is associated with various challenges. Promising novel tools for the administration of cancer vaccines has emerged from recent developments in nanoscale biomaterials. One current strategy to enhance targeted drug delivery, while minimizing drug-related toxicities, is the use of nanoparticles (NPs). These can be utilized for antigen delivery into DCs, which have been shown to provide potent T cell-stimulating effects. Therefore, NP delivery represents one promising approach for creating an effective and stable immune response without toxic side effects. The current review surveys cancer immunotherapy with particular attention toward NP-based delivery methods that target DCs.
The nuclear receptors REV-ERBα and REV-ERBβ have been demonstrated to play key roles in the regulation of numerous physiological functions, such as metabolism and the circadian rhythm. Recent studies ...have established the REV-ERBs’ roles in immunity, including macrophage and T cell responses. In contrast, their roles in dendritic cells have not been well defined. Dendritic cells are potent antigen presenting cells, connecting microbial sensing and innate immunity to adaptive immune responses. We demonstrate that both REV-ERBα and REV-ERBβ expression is upregulated during the course of bone marrow derived dendritic cell (BMDC) differentiation. BMDCs from REV-ERBα and REV-ERBβ deficient mice showed enhanced expression of maturation markers like CD86, MHCII, and proinflammatory cytokines. Conversely, treatment of BMDCs with a REV-ERB-specific agonist, SR9009, inhibited the expression of maturation markers and proinflammatory cytokines. Our study suggests the REV-ERBs act as negative regulators of dendritic cell development and activation. These results indicate that pharmacological modulation of REV-ERB activity could be an attractive strategy to modulate DC activation status and for DC-based therapies.
•The REV-ERBs are upregulated during BMDC development.•The REV-ERBs regulate MHCII and CD86 surface expression in BMDCs.•The REV-ERBs act as negative regulators of BMDC pro-inflammatory cytokine gene expression.•Small molecule modulation of REV-ERB activity affects BMDC maturation and gene expression.
HIV latency is the major barrier to a cure for people living with HIV (PLWH) on antiretroviral therapy (ART) because the virus persists in long-lived non-proliferating and proliferating latently ...infected CD4+ T cells. Latently infected CD4+ T cells do not express viral proteins and are therefore not visible to immune mediated clearance. Therefore, identifying interventions that can reverse latency and also enhance immune mediated clearance is of high interest. Interferons (IFNs) have multiple immune enhancing effects and can inhibit HIV replication in activated CD4+ T cells. However, the effects of IFNs on the establishment and reversal of HIV latency is not understood. Using an in vitro model of latency, we demonstrated that plasmacytoid dendritic cells (pDC) inhibit the establishment of HIV latency through secretion of type I IFNα, IFNβ and IFNω but not IFNε or type III IFNλ1 and IFNλ3. However, once latency was established, IFNα but no other IFNs were able to efficiently reverse latency in both an in vitro model of latency and CD4+ T cells collected from PLWH on suppressive ART. Binding of IFNα to its receptor expressed on primary CD4+ T cells did not induce activation of the canonical or non-canonical NFκB pathway but did induce phosphorylation of STAT1, 3 and 5 proteins. STAT5 has been previously demonstrated to bind to the HIV long terminal repeat and activate HIV transcription. We demonstrate diverse effects of interferons on HIV latency with type I IFNα; inhibiting the establishment of latency but also reversing HIV latency once latency is established.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the quest to treat intracellular infectious diseases and virus infection, nanoparticles (NPs) have been considered to be efficient tools for inducing potent immune responses, specifically cellular ...immunity. Antigen processing and presenting by antigen presenting cells (APCs) could influence immune response, especially the priming of T-cell-mediated cellular immunity. Here, we fabricated pH-responsive poly(d,l-lactic-co-glycolic acid) (PLGA) NPs with rapid antigen intracellular release behavior in APCs. The NPs, which had thin shells and large inner space, contain ammonium bicarbonate (NH4HCO3), which could regulate release in endosomes and lysosomes, acting as an antigen release promoter in dendritic cells (DCs), and were coencapsulated with antigen (ovalbumin, OVA). Hydrogen ions (H+) in DC endosomes and lysosomes (pH ∼5.0 and 6.5) could react with NH4HCO3 to generate NH3 and CO2, which broke NPs and released antigens. After uptake by DCs, antigens encapsulated in pH-responsive PLGA NPs could escape from lysosomes into the cytoplasm and be cross-presented. Moreover, the NPs induced up-regulation of co-stimulatory molecules and stimulated cytokine production. Mouse immunization with pH-responsive PLGA NPs induced greater lymphocyte activation, more antigen-specific CD8+ T cells, stronger cytotoxic capacity (IFN-γ and granzyme B), enhanced antigen-specific IgG antibodies, and higher serum IgG2a/IgG1, indicating cellular immunity. The NPs also improved generation of memory T cells to protect against reinfection. Thus, pH-responsive PLGA NPs, which induced strong cellular immune responses and offered antibody protection, could be potentially useful as effective vaccine delivery and adjuvant systems for the therapy of intracellular infectious diseases and virus infection.
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