Pollen Allergoid Research Articles

Study of the common wormwood allergoid

BACKGROUND: Allergens from the pollen of wormwood (Latin: Artemisia absinthium) are among the most dangerous in terms of allergization in central Russia, Europe and a number of other regions. The use of allergoids created using glutaraldehyde instead of native allergen extracts is due to the reduced risk of developing allergic reactions while maintaining immunogenicity and eliminating the highly toxic element formalin from the production process, which makes allergoids safer for use in allergen-specific immunotherapy. AIM: Obtaining an allergoid from wormwood pollen by treatment with glutaraldehyde to evaluate its properties prior to preclinical testing. MATERIALS AND METHODS: Purified extract of wormwood pollen, isolated by defatting and water-salt extraction, was dissolved in phosphate-buffered saline (PBS) pH 7.5, after which it was polymerized in 0.1 % glutaraldehyde solution. Stabilization was performed with sodium borohydride solution. The extract and allergoid of wormwood pollen were studied using chromatographic analysis and competitive enzyme-linked immunosorbent assay (ELISA). Then, intraperitoneal immunization with the obtained allergoid was carried out in CBA × C57Bl/6 (F1) mice. RESULTS: After evaluation of the specific allergenic activity using competitive immune assay ELISA with biotinylated extract of wormwood pollen allergen, it was shown that the 50 % inhibition point for the allergoid is determined at a drug concentration of 0.03 mg/ml, and for the allergen – already at 0.0008 mg/ml. Consequently, the allergenicity of wormwood pollen allergoid is significantly reduced compared to that of the original extract. In addition, the immunogenic activity of the obtained allergoid was confirmed in mice: the average optical density of the ELISA reaction, indicating the amount of IgG, in the group immunized with the allergoid was more than at least 1.5 times higher than the values for the allergen extract. CONCLUSIONS: During the work, an extract containing allergens of wormwood pollen was obtained. An allergoid was obtained on its basis by polymerization with glutaraldehyde. The obtained allergoid has a high molecular weight (the range shifted to 44–66 kDa), while it has low allergenic activity, in comparison with the original extract, and also retains immunogenicity. In this regard, this allergoid can become the basis for obtaining new ASIT treatments.

Short-course subcutaneous treatment with birch pollen allergoids greatly improves symptom and medication scores in birch allergy.

Subcutaneous immunotherapy has emerged as an effective option for treating allergic diseases. Here, we assessed the clinical impact of the mannan-conjugated birch pollen polymerized allergoid T502 in birch pollen-induced allergic rhinoconjunctivitis. In this prospective, randomized, double-blind placebo-controlled phase III trial, 298 birch pollen-allergic adult patients were treated across 28 trial sites in Germany. Patients received either placebo or 23,000 mTU T502 subcutaneously over five pre-seasonal visits. Efficacy was assessed by comparing the combined symptom and medication score (CSMS) between placebo and T502 during the peak birch pollen season 2022. Safety, tolerability and immunologic effects were also analyzed. During the peak birch pollen season, the median CSMS of the T502 group was reduced by 33% (p = 0.002) compared to placebo. The median daily symptom score and daily medication score were reduced by 30.4% (p < 0.001) and 56.3% (p = 0.045), respectively. Health related quality of life improved as reflected by reduction of RQLQ values by 31.5% (p < 0.0001). Production of Bet v 1 sIgG4 and Bet v 1 sIgG increased up to 6.2-fold and 3-fold respectively in the T502 group (p < 0.0001). The sIgE/sIgG4 ratio was strongly reduced in the T502 group at V7 (-62.9%, p < 0.0001). No fatalities nor serious adverse events were reported. In total, 16 systemic allergic reactions occurred (Grade I/II). Treatment with T502 significantly reduced symptoms and medication need in rhinoconjunctivitis patients. The treatment is well tolerated and safe.

Grass pollen allergoids conjugated with mannan for subcutaneous and sublingual immunotherapy: a dose-finding study.

Polymerized allergoids conjugated with mannan represent a novel approach of allergen immunotherapy targeting dendritic cells. In this study, we aimed to determine the optimal dose of mannan-allergoid conjugates derived from grass pollen (Phleum pratense and Dactylis glomerata) administered via either the subcutaneous or sublingual route. A randomized, double-blind, placebo-controlled trial with a double-dummy design was conducted, involving 162 participants across 12 centers in Spain. Subjects were randomly allocated to one of nine different treatment groups, each receiving either placebo or active treatment at doses of 500, 1,000, 3,000, or 5,000 mTU/mL over four months. Each participant received five subcutaneous (SC) doses of 0.5 mL each, every 30 days, and a daily sublingual (SL) dose of 0.2 mL. Participants who received active treatment through SC, received placebo through SL. Participants who received active treatment through SL, received placebo SC. One Group, as control, received bot SC and SL placebo. The primary efficacy outcome was the improvement in titrated nasal provocation tests (NPT) at the end of the study compared to baseline. Secondary outcomes included specific antibody (IgG4, IgE) and cellular (IL-10 producing and regulatory T cell) responses. All adverse events and side reactions were recorded and assessed. Post-treatment, the active groups showed improvements in NPT ranging from 33% to 53%, with the highest doses showing the greatest improvements regardless of the administration route. In comparison, the placebo group showed a 12% improvement. Significant differences over placebo were observed at doses of 3,000 mTU/mL (p=0.049 for SL, p=0.015 for SC) and 5,000 mTU/mL (p=0.011 for SL, p=0.015 for SC). A dose-dependent increase in IgG4 was observed following SC administration, and an increase in IL-10 producing cells for both routes of administration. No serious systemic or local adverse reactions were recorded, and no adrenaline was required. Grass pollen immunotherapy with mannan-allergoid conjugates was found to be safe and efficacious in achieving the primary outcome, whether administered via the subcutaneous or sublingual routes, at doses of 3,000 and 5,000 mTU/mL. https://www.clinicaltrialsregister.eu/ctr-search (EudraCT), identifier 2014-005471-88; https://www.clinicaltrials.gov, identifier NCT02654223.

Evolution Of Immunotherapy Against Pollen Allergy.

Allergic diseases have increased worldwide during the last century and are a major disease burden globally. Several substances can induce allergic sensitization and elicit allergic symptoms in sensitized individuals. Pollen grains are one of the main causes of allergic rhinitis and asthma, and the prevalence of different pollen species depends on the climate, geographical regions, flora, and season. In addition to avoiding exposure to pollens, anti-allergic drugs are commonly used to mitigate the symptoms of allergies. However, these drugs must be administered repeatedly as long as the symptoms prevail, usually life-long. Allergen immunotherapy (AIT) is currently the only disease-modifying approach that can prevent the natural progression of the disease (also known as an allergic march), provide a long-lasting therapeutic effect, and prevent the worsening of the symptoms and the occurrence of new sensitizations in allergic individuals. Since the pioneering clinical studies conducted more than 100 years ago using subcutaneously administered pollen extract to treat hay fever, significant advances have been made in the field of AIT. Starting from this pioneering approach, in this review, we have discussed the evolution of the products used for AIT with particular emphasis on pollen allergoids, the chemically modified pollen extracts characterized by lower allergenicity and comparable immunogenicity, and the different routes of administration used for AIT.

Subcutaneous immunotherapy with mannan-conjugated birch pollen allergoids is safe and well tolerated – data from 3 sequential trials

Subcutaneous immunotherapy has not only to be effective, but also needs to be safe and well tolerated in order to be accepted by physicians and patients. Here we show the safety data from 2 double-blind, placebo-controlled studies and 1 open follow-up study with mannan-conjugated birch pollen allergoids (T502).

Mannan-conjugated birch pollen allergoids reduce the combined symptom and medication score in birch pollen allergic patients already in the first treatment year and further decreases with prolonged treatment duration

The success of allergen immunotherapy for the treatment of allergic rhinoconjunctivitis is most evident during the respective pollen season. Here, we evaluated the combined symptom and medication score (CSMS) from 3 studies in patients with allergic rhinoconjunctivitis treated with mannan-conjugated birch pollen allergoids (T502).

Clinical Development of Mannan conjugated birch pollen allergoids for the treatment of birch pollen allergic patients – from first-in-human to approval in 3 studies

The aim of a drug development program for allergen immunotherapies is to get market authorization based on a good efficacy and safety/tolerability profile. Here, we describe the clinical development of Mannan conjugated birch pollen allergoids (T502) for the treatment of allergic rhinitis/rhinoconjunctivitis.

Modulation of Pro-Allergic T Cell Responses by PQ Grass 27600 SU as a Treatment for Seasonal Allergic Rhinitis: A RDBPC Pilot Study

PQ Grass, a grass pollen allergoid using MicroCrystalline Tyrosine and Monophosphoryl Lipid A as an adjuvant system, is a well-tolerated subcutaneous immunotherapy for the treatment of seasonal allergic rhinitis (SAR). We investigated the efficacy and cellular mechanisms underlying PQ Grass 27600 SU in subjects with SAR.

Induction of Local and Systemic Blocking Antibodies by PQ Grass 27600 SU for the Treatment of Seasonal Allergic Rhinitis: A RDBPC Pilot Study

PQ Grass, a grass pollen allergoid using MicroCrystalline Tyrosine and Monophosphoryl Lipid A as an adjuvant system, is a well-tolerated subcutaneous immunotherapy for seasonal allergic rhinitis. We hypothesised that PQ Grass 27600 SU is effective in inducing functional allergen-specific blocking antibodies.

Evaluation of the safety of dose escalation period of subcutaneous specific allergic immunotherapy in patients with rhino-conjunctivitis or allergic asthma previously vaccinated against SARS-CoV-2

BACKGROUND: More than 90% of the Spanish population has been vaccinated against the SARS-CoV-2 virus in our setting. The administration of this vaccine is not contraindicated in allergic subjects; however, it is unknown whether any precaution should be taken when initiating subcutaneous allergen immunotherapy after this vaccination. The objective of the study was to analyze the safety of subcutaneous allergen immunotherapy during the dose escalation phase in subjects sensitized to pollens or mites previously vaccinated against SARS-CoV-2. METHODS: An observational study with retrospective data collection from protocolled patients' medical records was designed. Outpatients older than 12 years with diagnosis of pollen or house dust mite allergic rhinitis with or without bronchial allergic asthma were selected who had completed the subcutaneous immunotherapy dose escalation phase. A complete SARS-CoV-2 vaccination was required for the inclusion. RESULTS: Three hundred and seventy-nine patients were included by 53 investigators. The mean age was 31 years old and 55,9% female. Time from last SARS-Cov-2 vaccination dose to subcutaneous immunotherapy initiation was 4.1 months (95%CI 3.8-4.4). subcutaneous immunotherapy with a pollen allergoid was administered to 135 patients (35.6%) with a total of 739 injections, while subcutaneous immunotherapy using a house dust mite allergoid was administered to 244 patients (64.4%) with a total of 1311 doses. During the dose escalation phase with the pollen allergoid, 45 patients (33.3%) suffered 93 local adverse reactions (12.6% of injections), while 17 patients (12.6%) experienced 17 systemic allergic reactions (2.3% of injections) of them 14 were World Allergy Organization Grade 1 and 3 of Grade 2. During the dose escalation phase with the house dust mite allergoid, 55 patients (22.5%) reported 133 local adverse reactions (10.1% of injections), and 7 patients (2.9%) showed 7 World Allergy Organization Grade 1 systemic reactions (0.5% of injections). No systemic reactions Grade 3 or higher were reported. CONCLUSIONS: The well-known safety profile of the subcutaneous allergen immunotherapy using pollen or house dust mite allergoids has not been changed after the SARS-CoV-2 vaccine administration. No relevant differences in the incidence of local or systemic allergic reactions during the dose escalation phase were identified, so it is considered that the patient’s safety has not been compromised to initiate this treatment after the SARS-CoV-2 vaccine administration.

A randomized, double-blind placebo-controlled first in human study with mannan-conjugated birch pollen allergoids administered subcutaneously to allergic patients

Aim of this phase IIa hybrid study was to identify the optimal dose of mannan-conjugated birch pollen allergoids (T502) for the short-course treatment of birch-pollen induced allergic rhinoconjunctivitis.

Induction of Allergen-Neutralizing IgG4 and IgA Blocking Antibodies Following Subcutaneous Immunotherapy with Mannan-Conjugated Birch Pollen Allergoid

Birch pollen SCIT using allergoid-mannan conjugate is a novel therapeutic approach that targets C-type lectin receptors on dendritic cells to induce tolerance. We hypothesized that SCIT with this conjugate induces allergen-specific IgA1, IgA2 and IgG4 and that the induction of these antibodies correlates with the binding of allergen-IgE complexes to CD23 on B cells.

Accelerated Dose Escalation with 3 Injections of an Aluminum Hydroxide-Adsorbed Allergoid Preparation of 6 Grasses Is Safe for Children and Adolescents with Moderate to Severe Allergic Rhinitis

A high-dose, accelerated escalation schedule during subcutaneous allergen-specific immunotherapy (AIT) is safe and well-tolerated in adults. However, there are no data in children and adolescents. The aim of the present trial was to assess safety and tolerability of an accelerated dose escalation schedule of an AIT with a grass pollen allergoid in children and adolescents with moderate to severe seasonal rhinoconjunctivitis in a multicenter, open-label, randomized phase II trial. The dose escalation scheme for patients in the One Strength Group included 3 injections with 1 strength B (10,000 TU/mL), whereas the dose escalation scheme for the Standard group included 7 injections with 2 strengths A (1,000 TU/mL) and B (10,000 TU/mL) of an allergoid grass pollen preparation. Overall, n = 50 children (n = 25 in each group; mean age 8.9 + 1.54 years) and n = 37 adolescents (n = 20 and n = 17; 14.2 + 1.62 years) were randomized. For all patients, the mean treatment duration was 59.4 days in the One Strength group and 88.6 days in the Standard group. Treatment-emergent adverse events (TEAEs) related to AIT were reported in 52 and 40% in children and 35 and 35.3% in adolescents, respectively. Systemic allergic reactions occurred in about 5% of our patients and were reported in more patients of the One Strength group (6.7 vs. 2.4%). All systemic reactions were classified as WAO Grade 1. Accelerated high-dose escalation with an aluminum hydroxide-adsorbed grass pollen allergoid can be initiated with a safety and tolerability profile comparable to the standard dose escalation schedule in children and adolescents with allergic rhinitis with or without asthma.

Evaluation of safety and tolerability of a rush up-dosing allergen-specific immunotherapy with grass pollen, birch, hazel, and alder allergoid in children with allergic rhinoconjunctivitis, with or without asthma.

Background:Usually, the number of injections required to achieve the maintenance dose in subcutaneous immunotherapy (SCIT) is relatively small for some of the currently used allergens, but this may still be uncomfortable for patients, thus compromising adherence and compliance.Objective:The purpose of this study was to evaluate the safety and tolerability of a dose acceleration of a conventional induction schedule using an allergoid extract of grass pollen, birch, hazel, and alder, needed to achieve the ideal maintenance dose.Methods:In this open-label study, 34 patients with allergic rhinoconjunctivitis, with or without asthma, were treated with SCIT using an allergoid for grass pollen or birch or mix trees with an increase in accelerated induction dose comprising only 3 injections, one per week, compared to a conventional induction pattern in five injections (once a week). Safety determination was assessed by evaluating local and systemic adverse events. Tolerability was evaluated by patients and physicians who performed the treatment.Results:No treatment-related adverse events were observed in any of the patients undergoing rush SCIT. No local reactions, no systemic reactions of any degree (WAO Grade) have been observed. Tolerability has always been rated as very good by both patients and physician.Conclusions:The induction phase, needed to achieve the monthly maintenance dose for a pollen extract, can be greatly accelerated, ensuring a tolerability comparable to that of the conventional schedule. (www.actabiomedica.it)

Real-World Adherence and Evidence of Subcutaneous and Sublingual Immunotherapy in Grass and Tree Pollen-Induced Allergic Rhinitis and Asthma.

PurposeAllergen immunotherapy (AIT), when continued for 3 years, is the only disease-modifying treatment for AR and asthma. Adherence is a key to ensure effectiveness, and poor adherence is a contraindication for AIT. The objective of this study was to evaluate real-world adherence to AIT with subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) preparations in patients allergic to grass or tree pollen. The impact of AIT on the consumption of asthma and rhinitis medication was also analyzed.Patients and MethodsIn this retrospective cohort analysis of a German longitudinal prescription database, the adherence of a grass and tree pollen allergoid was examined and compared to two sublingual AIT tablets/drops. Patients receiving grass or tree allergen-specific immunotherapy prescriptions were compared with non-AIT patients receiving symptomatic allergic rhinitis (AR) and asthma prescriptions. The study endpoints included therapy adherence, AR progression, and asthma progression. Multivariate regression analyses were used to estimate the effects of SCIT or SLIT, adjusting for variables related to demographics and prescriptions.ResultsSCIT adherence was 60.1–61.8% at 2 years and 35.0–37.5% at 3 years for the two allergens. SLIT adherence was distinctly lower (29.5–36.5% and 9.6–18.2%, respectively). Adherence in children was higher compared to adolescents or adults. All products were highly efficacious at reducing symptomatic AR medication consumption. SCIT also reduced asthma medication use for both allergens, whereas for SLIT these results were significant only for grasses but not trees.ConclusionSubcutaneous AIT in a real-world setting achieved significantly higher adherence rates compared to sublingual administration. SCIT reduced the use of rhinitis and asthma medication significantly for both allergens, while SLIT reduced the use of rhinitis medication for both allergens and the use of asthma medication for grasses only.

Accelerated Dose Escalation with Three Injections of an Aluminum Hydroxide-Adsorbed Allergoid Preparation of Six Grasses Is Safe for Patients with Moderate to Severe Allergic Rhinitis

Only few data on safety during high-dose, accelerated escalation schedules during subcutaneous allergen immunotherapy (AIT) are available. The aim of this study was to assess the safety and tolerability of an accelerated dose escalation schedule of AIT in adult patients with moderate to severe seasonal rhinoconjunctivitis in a multicenter, open-label, randomized phase II trial. The dose escalation scheme for patients in Group I (1 strength) included 3 injections with 1 strength, B (10,000 TU/mL), whereas the dose escalation scheme for Group II (standard) included 7 injections with 2 strengths, A (1,000 TU/mL) and B (10,000 TU/mL), of an aluminum hydroxide-adsorbed allergoid grass pollen preparation. Overall, 72 of 87 randomized patients (83.7%) reported at least 1 treatment-emergent adverse event (TEAE; 82.2 [Group I] vs. 85.4% [Group II]); 58.8% of all reported TEAEs were assessed as being related to AIT (60.0 vs. 48.8%). The most frequently reported AIT-related TEAEs were swelling (46.7 vs. 34.1%), erythema (28.9 vs. 36.6%), and pruritus (31.1 vs. 17.1%) at the site of the injection. Systemic allergic reactions occurred in 5 (5.8%) patients overall, with more being reported in the 1-strength group (4 [8.9%] vs. 1 [2.4%]). All systemic allergic reactions were classified as World Allergy Organization (WAO) Grade 1 or Grade 2 reactions. Accelerated high-dose escalation with an aluminum hydroxide-adsorbed grass pollen allergoid can be initiated with a safety and tolerability profile comparable to the standard dose escalation schedule in patients with allergic rhinitis with or without asthma.

Safety of an Accelerated Build-up Phase With Pollen Allergoids: A Retrospective Study.

Safety of an Accelerated Build-up Phase With Pollen Allergoids: A Retrospective Study.

Allergoids: Ready for the Future

Improving therapy for people with allergies is a continuously evolving area and, due to the increasing prevalence of allergic diseases, options such as pharmacotherapy and allergen avoidance are inadequate alone to control these diseases. Worldwide, approximately 400 million people are affected by allergic rhinitis (AR) and 300 million people by asthma.1 Unlike anti-allergy medications, a unique feature of allergen immunotherapy (AIT) is that it modifies the underlying cause of disease,2 suggesting that it may be an optimal treatment approach. Guidelines, such as those from the European Medicines Agency (EMA) in 2009,3 provide the basis for optimising trial design for the development of new AIT preparations. A wide range of treatment modalities, including recombinant allergens, have been developed, and results from several studies, some only published in trial registries, provide clarity and insights into optimising clinical trial design even further.4-13 Lessons learned from these studies, which are scientifically informative for the community, were explored in this session. In addition, the latest results were discussed from a dose-finding trial and a Phase III trial of a new allergoid treatment in development for patients with house dust mite (HDM)-induced asthma with or without AR or allergic rhinoconjunctivitis (ARC).14,15 Since AIT is recommended to be administered for 3 years, successful AIT requires adequate patient adherence over the long-term. The last section of this review focusses on strategies to optimise existing AIT and patient care, with a particular emphasis on reducing the number of injections during dose escalation when performing subcutaneous immunotherapy (SCIT) using pollen allergoids.

Early nonreactivity in the conjunctival provocation test predicts beneficial outcome of sublingual immunotherapy

BackgroundClinical practice needs a common parameter that can provide an early, reliable estimation of the outcome of sublingual immunotherapy (SLIT) in an upcoming pollen season. We investigated whether the conjunctival provocation test (CPT) can predict the beneficial outcome of SLIT in patients with allergic rhinoconjunctivitis after 4 weeks of treatment.MethodsWe conducted two separate prospective, randomized, double-blind, placebo-controlled, multicenter trials. Adults 18–75 years of age received placebo or SLIT tablets containing tree or grass pollen allergoids and underwent CPTs. Participants receiving SLIT were divided into two groups (reactive, nonreactive) according to their CPT reactions after 4 weeks of treatment. These two groups were compared with regard to clinical outcome parameters (total combined score, rhinoconjunctivitis total symptom score, total rescue medication score, well days) assessed during the pollen season for the 14-day (tree) or 30-day (tree/grass) peaks and for the entire 60-day seasons. Participants’ global evaluations of therapy after completing treatment were also compared.ResultsThe tree pollen trial randomized 188 participants; 182 participants were evaluable, 76 of whom received SLIT and were suitable for this post hoc analysis. The grass pollen trial included 90 participants; 82 participants were evaluable, 44 of whom underwent SLIT. Comparing SLIT participants who reacted to the CPT after 4 weeks (tree: 77.6%; grass: 79.5%) with those who ceased to show a reaction (tree: 22.4%; grass: 20.5%) (tree: P = 0.0001; grass: P = 0.003), the total combined score for the 14-day (P = 0.017) and 30-day peaks (P = 0.042) as well as the rhinoconjunctivitis total symptom score assessed for the 14-day peak (P = 0.024) were significantly lower in the nonreactive group of the tree pollen trial. In the grass pollen trial, the nonreactive group rated their SLIT treatment significantly better (P = 0.019).ConclusionsUsing clinically meaningful outcome parameters during the pollen season, both trials independently led to similar results when comparing participants’ reactions to the CPT 4 weeks after beginning SLIT. These results suggest that CPT allows an early estimation of allergic rhinoconjunctivitis symptoms before an upcoming season. Thus, the CPT can be used as a valuable parameter to predict the beneficial outcome of ongoing SLIT.Trial registrationBoth trials registered with the Medical Ethics Committee of the North Rhine Medical Council (EudraCT numbers 2012-004916-79 (grass pollen trial) and 2013-002129-43 (tree pollen trial)) and the German Federal Ministry of Health (Paul-Ehrlich-Institut).

Mite allergoids coupled to nonoxidized mannan from Saccharomyces cerevisae efficiently target canine dendritic cells for novel allergy immunotherapy in veterinary medicine

We have recently reported that grass pollen allergoids conjugated with nonoxidized mannan of Saccharomyces cerevisae using glutaraldehyde results in a novel hypoallergenic mannan-allergen complex with improved properties for allergen vaccination. Using this approach, human dendritic cells show a better allergen uptake and cytokine profile production (higher IL-10/IL-4 ratio) for therapeutic purposes. Here we aim to address whether a similar approach can be extended to dogs using canine dendritic cells. Six healthy Spanish Greyhound dogs were used as blood donors to obtain canine dendritic cells (DC) derived from peripheral blood monocytes. Allergens from Dermatophagoides farinae mite were polymerized and conjugated with nonoxidized mannan. Nuclear magnetic resonance (NMR), gel electrophoresis (SDS-PAGE), immunoblotting and IgE-ELISA inhibition studies were conducted to evaluate the main characteristics of the allergoid obtained. Mannan-allergen conjugate and controls were assayed in vitro for canine DC uptake and production of IL-4 and IL-10. The results indicate that the conjugation of D. farinae allergens with nonoxidized mannan was feasible using glutaraldehyde. The resulting product was a polymerized structure showing a high molecular weight as detected by NMR and SDS-PAGE analysis. The mannan-allergen conjugate was hypoallergenic with a reduced reactivity with specific dog IgE. An increase in both allergen uptake and IL-10/IL-4 ratio was obtained when canine DCs were incubated with the mannan-allergen conjugate, as compared with the control allergen preparations (unmodified D. farinae allergens and oxidized mannan-allergen conjugate). We conclude that hypoallergenic D. farinae allergens coupled to nonoxidized mannan is a novel allergen preparation suitable for canine allergy immunotherapy targeting dendritic cells.