CD103
CD11b
dendritic cells (DCs) are unique to the intestine, but the factors governing their differentiation are unclear. Here we show that transforming growth factor receptor 1 (TGFβR1) has an ...indispensable, cell intrinsic role in the development of these cells. Deletion of Tgfbr1 results in markedly fewer intestinal CD103
CD11b
DCs and a reciprocal increase in the CD103
CD11b
dendritic cell subset. Transcriptional profiling identifies markers that define the CD103
CD11b
DC lineage, including CD101, TREM1 and Siglec-F, and shows that the absence of CD103
CD11b
DCs in CD11c-Cre.Tgfbr1
mice reflects defective differentiation from CD103
CD11b
intermediaries, rather than an isolated loss of CD103 expression. The defect in CD103
CD11b
DCs is accompanied by reduced generation of antigen-specific, inducible FoxP3
regulatory T cells in vitro and in vivo, and by reduced numbers of endogenous Th17 cells in the intestinal mucosa. Thus, TGFβR1-mediated signalling may explain the tissue-specific development of these unique DCs.Developmental cues for the different dendritic cell (DC) subsets in the intestine are yet to be defined. Here the authors show that TGFβR1 signalling is needed for development of CD103
CD11b
intestinal DCs from CD103
CD11b
cells and that they contribute to the generation of Th17 and regulatory T cells.
Intestinal macrophages (mφ) form one of the largest populations of mφ in the body and are vital for the maintenance of gut homeostasis. They have several unique properties and are derived from local ...differentiation of classical Ly6C
monocytes, but the factors driving this tissue-specific process are not understood. Here we have used global transcriptomic analysis to identify a unique homeostatic signature of mature colonic mφ that is acquired as they differentiate in the mucosa. By comparing the analogous monocyte differentiation process found in the dermis, we identify TGFβ as an indispensable part of monocyte differentiation in the intestine and show that it enables mφ to adapt precisely to the requirements of their environment. Importantly, TGFβR signaling on mφ has a crucial role in regulating the accumulation of monocytes in the mucosa, via mechanisms that are distinct from those used by IL10.
Microneedle devices have been proposed as a minimally invasive delivery system for the intradermal administration of nucleic acids, both plasmid DNA (pDNA) and siRNA, to treat localised disease or ...provide vaccination. Different microneedle types and application methods have been investigated in the laboratory, but limited and irreproducible levels of gene expression have proven to be significant challenges to pre-clinical to clinical progression. This study is the first to explore the potential of a hollow microneedle device for the delivery and subsequent expression of pDNA in human skin. The regulatory approved MicronJet600® (MicronJet hereafter) device was used to deliver reporter plasmids (pCMVβ and pEGFP-N1) into viable excised human skin. Exogenous gene expression was subsequently detected at multiple locations that were distant from the injection site but within the confines of the bleb created by the intradermal bolus. The observed levels of gene expression in the tissue are at least comparable to that achieved by the most invasive microneedle application methods e.g. lateral application of a microneedle. Gene expression was predominantly located in the epidermis, although also evident in the papillary dermis. Optical coherence tomography permitted real time visualisation of the sub-surface skin architecture and, unlike a conventional intradermal injection, MicronJet administration of a 50μL bolus appears to create multiple superficial microdisruptions in the papillary dermis and epidermis. These were co-localised with expression of the pCMVβ reporter plasmid. We have therefore shown, for the first time, that a hollow microneedle device can facilitate efficient and reproducible gene expression of exogenous naked pDNA in human skin using volumes that are considered to be standard for intradermal administration, and postulate a hydrodynamic effect as the mechanism of gene delivery.
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Secretory intestinal IgA can protect from re-infection with rotavirus (RV), but very little is known about the mechanisms that induce IgA production during intestinal virus infections. Classical ...dendritic cells (cDCs) in the intestine can facilitate both T cell-dependent and -independent secretory IgA. Here, we show that BATF3-dependent cDC1, but not cDC2, are critical for the optimal induction of RV-specific IgA responses in the mesenteric lymph nodes. This depends on the selective expression of the TGFβ-activating integrin αvβ8 by cDC1. In contrast, αvβ8 on cDC1 is dispensible for steady state immune homeostasis. Given that cDC2 are crucial in driving IgA during steady state but are dispensable for RV-specific IgA responses, we propose that the capacity of DC subsets to induce intestinal IgA responses reflects the context, as opposed to an intrinsic property of individual DC subsets.
Background
Immunomodulatory interventions play a key role in the treatment of infections and cancer as well as allergic diseases. Adjuvants such as micro‐ and nanoparticles are often added to ...immunomodulatory therapies to enhance the triggered immune response. Here, we report the immunological assessment of novel and economically manufactured microparticle adjuvants, namely strontium‐doped hydroxyapatite porous spheres (SHAS), which we suggest for the use as adjuvant and carrier in allergen‐specific immunotherapy (ASIT).
Methods and results
Scanning electron microscopy revealed that the synthesis procedure developed for the production of SHAS results in a highly homogeneous population of spheres. Strontium‐doped hydroxyapatite porous spheres bound and released proteins such as ovalbumin (OVA) or the major cat allergen Fel d 1. SHAS‐OVA were taken up by human monocyte‐derived dendritic cells (mdDCs) and murine DCs and did not have any necrotic or apoptotic effects even at high densities. In a murine model of ASIT for allergic asthmatic inflammation, we found that OVA released from subcutaneously injected SHAS‐OVA led to a sustained stimulation of both CD4+ and CD8+ T cells. Allergen‐specific immunotherapy with SHAS‐OVA as compared to soluble OVA resulted in similar humoral responses but in a higher efficacy as assessed by symptom scoring.
Conclusion
We conclude that SHAS may constitute a suitable carrier and adjuvant for ASIT with great potential due to its unique protein‐binding properties.
There is no clinically available cancer immunotherapy that exploits Langerhans cells (LCs), the epidermal precursors of dendritic cells (DCs) that are the natural agent of antigen delivery. We ...developed a DNA formulation with a polymer and obtained synthetic 'pathogen-like' nanoparticles that preferentially targeted LCs in epidermal cultures. These nanoparticles applied topically under a patch-elicited robust immune responses in human subjects. To demonstrate the mechanism of action of this novel vaccination strategy in live animals, we assembled a high-resolution two-photon laser scanning-microscope. Nanoparticles applied on the native skin poorly penetrated and poorly induced LC motility. The combination of nanoparticle administration and skin treatment was essential both for efficient loading the vaccine into the epidermis and for potent activation of the LCs to migrate into the lymph nodes. LCs in the epidermis picked up nanoparticles and accumulated them in the nuclear region demonstrating an effective nuclear DNA delivery in vivo. Tissue distribution studies revealed that the majority of the DNA was targeted to the lymph nodes. Preclinical toxicity of the LC-targeting DNA vaccine was limited to mild and transient local erythema caused by the skin treatment. This novel, clinically proven LC-targeting DNA vaccine platform technology broadens the options on DC-targeting vaccines to generate therapeutic immunity against cancer.
Macrophages are a heterogeneous cell population involved in tissue homeostasis, inflammation, and various pathologies. Although the major tissue-resident macrophage populations have been extensively ...studied, interstitial macrophages (IMs) residing within the tissue parenchyma remain poorly defined. Here we studied IMs from murine lung, fat, heart, and dermis. We identified two independent IM subpopulations that are conserved across tissues: Lyve1
MHCII
CX3CR1
(Lyve1
MHCII
) and Lyve1
MHCII
CX3CR1
(Lyve1
MHCII
) monocyte-derived IMs, with distinct gene expression profiles, phenotypes, functions, and localizations. Using a new mouse model of inducible macrophage depletion (
), we found that the absence of Lyve1
MHCII
IMs exacerbated experimental lung fibrosis. Thus, we demonstrate that two independent populations of IMs coexist across tissues and exhibit conserved niche-dependent functional programming.
To determine which CD3 components are required for early T cell development, we generated mice with a targeted mutation of the CD3‐epsilon gene and characterized their T cell populations relative to ...those found in CD3‐zeta/eta‐and recombinase activating gene (RAG)‐deficient mice. In the absence of intact CD3‐epsilon subunit, thymocytes do not progress beyond the CD44‐/lowCD25+ triple‐negative stage and appear to be arrested at the very same developmental control point as RAG‐deficient thymocytes. In contrast, the disruption of the CD3‐epsilon/eta gene does not totally abrogate the progression through this control point. CD3‐epsilon‐deficient thymocytes do rearrange their T cell receptor (TCR) beta gene segments and produce low levels of full‐length TCR beta transcripts. Taken together, these results establish an essential role for the CD3‐epsilon gene products during T cell development and further suggest that the CD3‐epsilon polypeptides start to exert their function as part of a pre‐TCR through which CD44‐/lowCD25+ triple‐negative cells monitor the occurrence of productive TCR beta gene rearrangements. Finally, the absence of intact CD3‐epsilon polypeptides had no discernible effect on the completion of TCR gamma and TCR delta gene rearrangements, emphasizing that they are probably not subjected to the same epigenetic controls as those operating on the expression of TCR alpha and beta genes.
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