Colony stimulating factor-1 (Csf-1) receptor and its ligand Csf-1 control macrophage development, maintenance, and function. The development of both Langerhans cells (LCs) and microglia is highly ...dependent on Csf-1 receptor signaling but independent of Csf-1. Here we show that in both mice and humans, interleukin-34 (IL-34), an alternative ligand for Csf-1 receptor, is produced by keratinocytes in the epidermis and by neurons in the brain. Mice lacking IL-34 displayed a marked reduction of LCs and a decrease of microglia, whereas monocytes, dermal, and lymphoid tissue macrophages and DCs were unaffected. We identified IL-34 as a nonredundant cytokine for the development of LCs during embryogenesis as well as for their homeostasis in the adult skin. Whereas inflammation-induced repopulation of LCs appears to be dependent on Csf-1, once inflammation is resolved, LC survival is again IL-34-dependent. In contrast, microglia and their yolk sac precursors develop independently of IL-34 but rely on it for their maintenance in the adult brain.
► IL-34 is critical for the development and maintenance of LCs ► IL-34 is required for LC maintenance but not monocyte-derived repopulation in inflammation ► IL-34 is critical for the homeostasis of adult microglia ► IL-34 protein is produced in the epidermis and brain of mice and humans
Peanut allergy is a severe and increasingly frequent disease with high medical, psychosocial, and economic burden for affected patients and wider society. A causal, safe, and effective therapy is not ...yet available.
We sought to develop an immunogenic, protective, and nonreactogenic vaccine candidate against peanut allergy based on virus-like particles (VLPs) coupled to single peanut allergens.
To generate vaccine candidates, extracts of roasted peanut (Ara R) or the single allergens Ara h 1 or Ara h 2 were coupled to immunologically optimized Cucumber Mosaic Virus–derived VLPs (CuMVtt). BALB/c mice were sensitized intraperitoneally with peanut extract absorbed to alum. Immunotherapy consisted of a single subcutaneous injection of CuMVtt coupled to Ara R, Ara h 1, or Ara h 2.
The vaccines CuMVtt-Ara R, CuMVtt-Ara h 1, and CuMVtt-Ara h 2 protected peanut-sensitized mice against anaphylaxis after intravenous challenge with the whole peanut extract. Vaccines did not cause allergic reactions in sensitized mice. CuMVtt-Ara h 1 was able to induce specific IgG antibodies, diminished local reactions after skin prick tests, and reduced the infiltration of the gastrointestinal tract by eosinophils and mast cells after oral challenge with peanut. The ability of CuMVtt-Ara h 1 to protect against challenge with the whole extract was mediated by IgG, as shown via passive IgG transfer. FcγRIIb was required for protection, indicating that immune complexes with single allergens were able to block the allergic response against the whole extract, consisting of a complex allergen mixture.
Our data suggest that vaccination using single peanut allergens displayed on CuMVtt may represent a novel therapy against peanut allergy with a favorable safety profile.
Background Subcutaneous allergen-specific immunotherapy frequently causes allergic side effects and requires 30 to 80 injections over 3 to 5 years. Objective We sought to improve immunotherapy by ...using intralymphatic allergen administration (intralymphatic immunotherapy ILIT) and by targeting allergen to the MHC class II pathway. Methods Recombinant major cat dander allergen Fel d 1 was fused to a translocation sequence (TAT) and to part of the human invariant chain, generating a modular antigen transporter (MAT) vaccine (MAT–Fel d 1). In a randomized double-blind trial ILIT with MAT–Fel d 1 in alum was compared with ILIT with placebo (saline in alum) in allergic patients ( ClinicalTrials.gov NCT00718679 ). Results ILIT with MAT–Fel d 1 elicited no adverse events. After 3 placebo injections within 2 months, nasal tolerance increased less than 3-fold, whereas 3 intralymphatic injections with MAT–Fel d 1 increased nasal tolerance 74-fold ( P < .001 vs placebo). ILIT with MAT–Fel d 1 stimulated regulatory T-cell responses ( P = .026 vs placebo) and increased cat dander–specific IgG4 levels by 5.66-fold ( P = .003). The IgG4 response positively correlated with IL-10 production ( P < .001). Conclusion In a first-in-human clinical study ILIT with MAT–Fel d 1 was safe and induced allergen tolerance after 3 injections.
Background Epicutaneous allergen administration using a patch may be an alternative to subcutaneous or sublingual immunotherapy. Objective To optimize treatment dose and to demonstrate the efficacy ...and safety of epicutaneous immunotherapy. Methods This monocentric, placebo-controlled, double-blind trial included 132 patients with grass pollen–induced rhinoconjunctivitis. In February 2008, patients were randomly allocated to receive placebo or 3 different doses of allergen. Before and during the pollen season 2008, patients received 6 weekly patches. Efficacy was assessed 4 to 5 months later (n = 110) and during the pollen season of the treatment-free follow-up year in 2009 (n = 93). The primary outcome was patient-reported changes in hay fever symptoms assessed by a visual analog scale. Secondary outcome measures were weekly visual analog scale symptom scores during pollen season, use of rescue medication, changes in conjunctival and skin reactivity, as well as safety. Results Hay fever symptoms during the pollen season were reduced by more than 30% in 2008 and by 24% in 2009 in the high-dose group as compared with that in the placebo group, and the alleviation of symptoms in the follow-up year was dependent on the treatment dose. Higher allergen doses were associated with drug-related adverse events (AEs), predominantly manifested by pruritus, erythema, wheal, or eczema. Eleven systemic AEs of grades 1 to 2 required treatment and led to study exclusion. The dropout rate due to AEs was 8.3%. No drug-related serious AE was recorded. Conclusion Epicutaneous immunotherapy is safe and efficacious in a dose-dependent manner after 6 patches only.
Background Subcutaneous allergen-specific immunotherapy is an effective treatment of IgE-mediated allergies, but it requires repeated allergen injections with a risk of systemic allergic reactions. ...Transcutaneous immunotherapy may improve patient compliance and safety. Objective To assess the safety and efficacy of epicutaneous allergen immunotherapy. Methods This monocentric, placebo-controlled, double-blind trial was conducted from March 2006 to December 2007 at the University Hospital Zurich. Thirty-seven adult patients with positive skin prick and nasal provocation tests to grass pollen were randomized to receive patches containing either allergen (n = 21) or placebo (n = 16). Treatment took place before and during the pollen season 2006, and follow-up visits took place before (n = 26) and after the pollen season 2007 (n = 30). The primary outcome measures were nasal provocation tests. Results Allergen-treated patients showed significantly decreased scores in nasal provocation tests in the first ( P < .001) and second year ( P = .003) after treatment. In contrast, placebo-treated patients had decreased scores in the first treatment year, 2006 ( P = .03), but the effect diminished in the second year ( P = .53). Although improvement of nasal provocation test scores was not significantly better in the verum versus placebo group, the overall treatment success was rated significantly higher by the allergen-treated group than by the placebo group (2006, P = .02; 2007, P = .005). No severe adverse events were observed. Occurrence of eczema after allergen patch applications proved stimulation of specific T-cell responses, but was noted as an adverse effect of the treatment. Conclusion Epicutaneous allergen immunotherapy is a promising strategy to treat allergies and merits further investigation.
Mitochondrial dysfunction is a prominent feature of Alzheimer's disease (AD) and increased production of reactive oxygen species (ROS) has been described in postmortem brain samples and animal ...models. However, these observations were made at a late stage of disease and the inability to examine an early, presymptomatic phase in human neurons impeded our understanding of cause or consequence of mitochondrial dysfunction in AD. We used human induced pluripotent stem cell-derived neuronal cells (iN cells) from sporadic AD (SAD) patients and healthy control subjects (HCS) to show aberrant mitochondrial function in patient-derived cells. We observed that neuronal cultures from some patients produced more ROS and displayed higher levels of DNA damage. Furthermore, patient-derived cells showed increased levels of oxidative phosphorylation chain complexes, whereas mitochondrial fission and fusion proteins were not affected. Surprisingly, these effects neither correlated with Aβ nor phosphorylated and total tau levels. Synaptic protein levels were also unaffected in SAD iN cells. The results of this study give new insights into constitutional metabolic changes in neurons from subjects prone to develop Alzheimer's pathology. They suggest that increased ROS production may have an integral role in the development of sporadic AD prior to the appearance of amyloid and tau pathology.
•Aberrant ROS production in AD patient iN cells does not correlate with Aβ or p-tau.•High ROS levels correlate with increased DNA damage.•Altered levels of oxphos complexes are found in AD patient-derived iN cells.•Synaptic proteins are unaffected.
The adenosine deaminase inhibitor 2′-deoxycoformycin (pentostatin, Nipent) has been used since 1982 to treat leukemia and lymphoma, but its mode of action is still unknown. Pentostatin was reported ...to decrease methylation of cellular RNA. We discovered that RNA extracted from pentostatin-treated cells or mice has enhanced immunostimulating capacities. Accordingly, we demonstrated in mice that the anticancer activity of pentostatin required Toll-like receptor 3, the type I interferon receptor, and T cells. Upon systemic administration of pentostatin, type I interferon is produced locally in tumors, resulting in immune cell infiltration. We combined pentostatin with immune checkpoint inhibitors and observed synergistic anti-cancer activities. Our work identifies pentostatin as a new class of an anticancer immunostimulating drug that activates innate immunity within tumor tissues and synergizes with systemic T cell therapies.
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Our experiments show that pentostatin indirectly triggers TLR3-TRIF signaling in tumors to induce local production of type I interferon. We also demonstrate that pentostatin synergizes with anti-PD1 therapy. Our discoveries will allow repurposing of pentostatin for combination treatments incorporating local induction of type I interferon at tumor sites with immunotherapies.
The only causative treatment for IgE-mediated allergies is allergen-specific immunotherapy. However, fewer than 5% of allergy patients receive immunotherapy because of its long duration and risk of ...allergic side effects. We aimed at enhancing s.c. immunotherapy by direct administration of allergen into s.c. lymph nodes. The objective was to evaluate safety and efficacy compared with conventional s.c. immunotherapy. In a monocentric open-label trial, 165 patients with grass pollen-induced rhinoconjunctivitis were randomized to receive either 54 s.c. injections with pollen extract over 3 years cumulative allergen dose 4,031,540 standardized quality units (SQ-U) or 3 intralymphatic injections over 2 months (cumulative allergen dose 3,000 SQ-U). Patients were evaluated after 4 months, 1 year, and 3 years by nasal provocation, skin prick testing, IgE measurements, and symptom scores. Three low-dose intralymphatic allergen administrations increased tolerance to nasal provocation with pollen already within 4 months (P < 0.001). Tolerance was long lasting and equivalent to that achievable after standard s.c. immunotherapy (P = 0.291 after 3 years). Intralymphatic immunotherapy ameliorated hay fever symptoms (P < 0.001), reduced skin prick test reactivity (P < 0.001), decreased specific serum IgE (P < 0.001), caused fewer adverse events than s.c. immunotherapy (P = 0.001), enhanced compliance (P < 0.001), and was less painful than venous puncture (P = 0.018). In conclusion, intralymphatic allergen administration enhanced safety and efficacy of immunotherapy and reduced treatment time from 3 years to 8 weeks.
Particulate delivery systems such as liposomes and polymeric nano- and microparticles are attracting great interest for developing new vaccines. Materials and formulation properties essential for ...this purpose have been extensively studied, but relatively little is known about the influence of the administration route of such delivery systems on the type and strength of immune response elicited. Thus, the present study aimed at elucidating the influence on the immune response when of immunising mice by different routes, such as the subcutaneous, intradermal, intramuscular, and intralymphatic routes with ovalbumin-loaded liposomes,
N-trimethyl chitosan (TMC) nanoparticles, and poly(lactide-
co-glycolide) (PLGA) microparticles, all with and without specifically selected immune-response modifiers. The results showed that the route of administration caused only minor differences in inducing an antibody response of the IgG1 subclass, and any such differences were abolished upon booster immunisation with the various adjuvanted and non-adjuvanted delivery systems. In contrast, the administration route strongly affected both the kinetics and magnitude of the IgG2a response. A single intralymphatic administration of all evaluated delivery systems induced a robust IgG2a response, whereas subcutaneous administration failed to elicit a substantial IgG2a response even after boosting, except with the adjuvanted nanoparticles. The intradermal and intramuscular routes generated intermediate IgG2a titers. The benefit of the intralymphatic administration route for eliciting a Th1-type response was confirmed in terms of IFN-gamma production of isolated and re-stimulated splenocytes from animals previously immunised with adjuvanted and non-adjuvanted liposomes as well as with adjuvanted microparticles. Altogether the results show that the IgG2a associated with Th1-type immune responses are sensitive to the route of administration, whereas IgG1 response associated with Th2-type immune responses were relatively insensitive to the administration route of the particulate delivery systems. The route of administration should therefore be considered when planning and interpreting pre-clinical research or development on vaccine delivery systems.
A cross sectional analysis of vaccines based on DDA liposomes, chitosan nanoparticles or PLGA microspheres revealed that the administration route strongly affected the quality and strength of induced immune responses.
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