A Highly Sensitive Cell-Based TLR Reporter Platform for the Specific Detection of Bacterial TLR Ligands

Toll-like receptors (TLRs) are primary pattern recognition receptors (PRRs), which recognize conserved microbial components. They play important roles in innate immunity but also in the initiation of adaptive immune responses. Impurities containing TLR ligands are a frequent problem in research but also for the production of therapeutics since TLR ligands can exert strong immunomodulatory properties even in minute amounts. Consequently, there is a need for sensitive tools to detect TLR ligands with high sensitivity and specificity. Here we describe the development of a platform based on a highly sensitive NF-κB::eGFP reporter Jurkat JE6-1 T cell line for the detection of TLR ligands. Ectopic expression of TLRs and their coreceptors and CRISPR/Cas9-mediated deletion of endogenously expressed TLRs was deployed to generate reporter cell lines selectively expressing functional human TLR2/1, TLR2/6, TLR4 or TLR5 complexes. Using well-defined agonists for the respective TLR complexes we could demonstrate high specificity and sensitivity of the individual reporter lines. The limit of detection for LPS was below 1 pg/mL and ligands for TLR2/1 (Pam3CSK4), TLR2/6 (Fsl-1) and TLR5 (flagellin) were detected at concentrations as low as 1.0 ng/mL, 0.2 ng/mL and 10 pg/mL, respectively. We showed that the JE6-1 TLR reporter cells have the utility to characterize different commercially available TLR ligands as well as more complex samples like bacterially expressed proteins or allergen extracts. Impurities in preparations of microbial compounds as well as the lack of specificity of detection systems can lead to erroneous results and currently there is no consensus regarding the involvement of TLRs in the recognition of several molecules with proposed immunostimulatory functions. This reporter system represents a highly suitable tool for the definition of structural requirements for agonists of distinct TLR complexes.

Synthesis of N-Glycans Implicated in Asthma and Allergy

<p><b>Asthma and allergies affect a large number of people, with over 300 million people worldwide suffering from asthma alone. Although, on the ‟macroscopic‟ level, it is known how allergens trigger allergic reactions, it is not known how an allergen's ‟micro‟ structure causes such a profound allergic response in sensitised individuals. A review of inter-species carbohydrate motifs revealed a striking similarity between carbohydrate moieties (N-glycans) present on antigens derived from species known to give an allergic T helper (Th) 2 response in humans (such as pollen, schistosomes, and food allergens). Preliminary studies on mixtures of allergen extracts have suggested that these carbohydrate motifs (glycoproteins) bias the immune response to an allergic (Th2) response.</b></p> <p>This project presents work conducted towards the synthesis of three fragments of a larger N-glycan found on allergens. The synthesis of these N-glycans will allow the first detailed study regarding the relationship between N-glycan structure and Th2 bias to be performed and thereby aid in our understanding of the molecular triggers of asthma. Ultimately, this could lead to the elucidation of the mechanisms of the allergic Th2 immune response.</p>

Synthesis of N-Glycans Implicated in Asthma and Allergy

<p><b>Asthma and allergies affect a large number of people, with over 300 million people worldwide suffering from asthma alone. Although, on the ‟macroscopic‟ level, it is known how allergens trigger allergic reactions, it is not known how an allergen's ‟micro‟ structure causes such a profound allergic response in sensitised individuals. A review of inter-species carbohydrate motifs revealed a striking similarity between carbohydrate moieties (N-glycans) present on antigens derived from species known to give an allergic T helper (Th) 2 response in humans (such as pollen, schistosomes, and food allergens). Preliminary studies on mixtures of allergen extracts have suggested that these carbohydrate motifs (glycoproteins) bias the immune response to an allergic (Th2) response.</b></p> <p>This project presents work conducted towards the synthesis of three fragments of a larger N-glycan found on allergens. The synthesis of these N-glycans will allow the first detailed study regarding the relationship between N-glycan structure and Th2 bias to be performed and thereby aid in our understanding of the molecular triggers of asthma. Ultimately, this could lead to the elucidation of the mechanisms of the allergic Th2 immune response.</p>

Synthesis of N-glycans implicated in asthma and allergy

<p>Asthma and allergies affect a large number of people, with over 300 million people worldwide suffering from asthma alone. Although, on the ‟macroscopic‟ level, it is known how allergens trigger allergic reactions, it is not known how an allergen's ‟micro‟ structure causes such a profound allergic response in sensitised individuals. A review of inter-species carbohydrate motifs revealed a striking similarity between carbohydrate moieties (N-glycans) present on antigens derived from species known to give an allergic T helper (Th) 2 response in humans (such as pollen, schistosomes, and food allergens). Preliminary studies on mixtures of allergen extracts have suggested that these carbohydrate motifs (glycoproteins) bias the immune response to an allergic (Th2) response. This project presents work conducted towards the synthesis of three fragments of a larger N-glycan found on allergens. The synthesis of these N-glycans will allow the first detailed study regarding the relationship between N-glycan structure and Th2 bias to be performed and thereby aid in our understanding of the molecular triggers of asthma. Ultimately, this could lead to the elucidation of the mechanisms of the allergic Th2 immune response.</p>

Synthesis of N-glycans implicated in asthma and allergy

<p>Asthma and allergies affect a large number of people, with over 300 million people worldwide suffering from asthma alone. Although, on the ‟macroscopic‟ level, it is known how allergens trigger allergic reactions, it is not known how an allergen's ‟micro‟ structure causes such a profound allergic response in sensitised individuals. A review of inter-species carbohydrate motifs revealed a striking similarity between carbohydrate moieties (N-glycans) present on antigens derived from species known to give an allergic T helper (Th) 2 response in humans (such as pollen, schistosomes, and food allergens). Preliminary studies on mixtures of allergen extracts have suggested that these carbohydrate motifs (glycoproteins) bias the immune response to an allergic (Th2) response. This project presents work conducted towards the synthesis of three fragments of a larger N-glycan found on allergens. The synthesis of these N-glycans will allow the first detailed study regarding the relationship between N-glycan structure and Th2 bias to be performed and thereby aid in our understanding of the molecular triggers of asthma. Ultimately, this could lead to the elucidation of the mechanisms of the allergic Th2 immune response.</p>

Sensitisation To Imbrasia Belina (Mopane Worm) and Other Local Allergens in Rural Gwanda District of Zimbabwe

Background The prevalence of allergic diseases is increasing in Zimbabwe and the data relate to local as well as exotic allergen sources. As entomophagy, the practice of eating insects, is a recognised source of local allergens, we sought to measure the prevalence of and risk factors for sensitisation to Imbrasia belina (mopane worm), a popular edible insect. This was investigated alongside other locally relevant allergens in a rural community in Gwanda district, south of Zimbabwe. Methods A cross sectional study was conducted among 496 adults and children aged 10 years and above in Gwanda district, a mopane worm harvesting area in Zimbabwe. Data on individual characteristics, mopane worm exposure factors, sensitivity to commercial allergen extracts (Stallergenes, France) and in-house extracts of mopane worm (Imbrasia belina) and mopane leaves (Colophospermum mopane) were collected at a local clinic. Data were analysed using Stata version 13 software. Results The prevalence of sensitisation to at least one allergen was 31.17% (n = 144). The prevalence of atopy was higher in adults (33.33%) than in children (23.53%) (p = 0.059). The commonest inhalant allergen sources were mopane worm (14.29%), Tyrophagus putrescentiae (14.29%), mopane leaves (13.42%), Alternaria alternata (6.49%) and Dermatophagoides pteronyssinus (6.49%). Polysensitisation was demonstrated in the study population and of the 108 participants who were sensitised to two or more allergens, 66 (61%) were women. Sensitisation to mopane worm and mopane leaves often clustered with Tyrophagus putrescentiae amongst adults. Adjusted logistic regression analyses between mopane worm sensitisation and self-reported exposure variables showed that sensitisation was more likely amongst mopane worm harvesters (OR = 1.92, 95%CI = 0.77–4.79), those who cooked or roasted mopane worms during harvesting (OR = 2.69, 95%CI = 0.78–9.31) and harvesting without personal protective equipment (PPE) (OR = 2.12, 95%CI = 0.83–5.44) compared to non-harvesters. Conclusion Atopic sensitization was common in this mopane worm harvesting community in Gwanda district of Zimbabwe. There was frequent co-sensitisation of mopane worm and mopane leaves with Tyrophagus putrescentiae in children and adults. It is important to determine the clinical relevance of our findings, particularly relating to mopane worm sensitisation.

Comparison of weight per volume and protein nitrogen units in non-standardized allergen extracts: implications for prescribing subcutaneous immunotherapy

Background Allergen extracts used in subcutaneous immunotherapy can be standardized or non-standardized. Standardized extracts are available in specific biological potencies, presumably making their biological activity more consistent. The majority of allergen extracts are non-standardized and may have less consistent potencies. Non-standardized extracts are labeled as weight per volume or protein nitrogen units (PNUs). Neither method provides direct information regarding the extract’s biologic potency. The purpose of this study was to compare weight per volume versus PNU concentrations for 4 non-standardized allergen extracts prepared by two allergen manufacturers. The potencies were compared to current North American practice recommendations. Methods The weight per volume and PNU values were provided for 4 non-standardized extracts—birch, short ragweed, dog hair and Alternaria—from HollisterStier and Stallergenes Greer. Weight per volume and PNU concentrations were compared for each of these extracts from both manufacturers. From the raw data, we calculated the corresponding PNU values for a weight per volume of 1:100 and 1:200 for each extract. Similarly, we calculated the corresponding weight per volume including a range of PNU values, for 1000, 2000, 3000, 4000 and 5000 PNU/ml. Results Birch extract has low PNU concentration, below 5000, for a weight per volume of 1:200 for both HollisterStier and Stallergenes Greer. In contrast, for both HollisterStier and Stallergenes Greer ragweed extract, a weight per volume of 1:200 corresponds to a PNU concentration greater than 5000. Dog extract for a weight per volume of 1:200, and even for 1:100, corresponds to very low PNUs for both companies. For Alternaria, corresponding PNU concentrations for HollisterStier is low at only 500 while over 5000 for Stallergenes Greer. Conclusions Our results show variability when comparing weight per volume and PNU concentrations for both Hollister-Stier and Stallergenes Greer products. We suggest selecting a PNU dose that corresponds to a weight per volume of 1:200 as this may improve patient safety. Our recommendations for starting PNU dose for the four non-standardized extracts are 1500 for birch, 5000 for ragweed, 25 for dog, and 500 for Alternaria when using HollisterStier products; 2300 for birch, 5000 for ragweed, 1200 for dog, and 5000 for Alternaria when using Stallergenes Greer products. If the starting PNU concentration is considerably below 5000 for a weight per volume of 1:200 slow up-titration is advised. Conversely, for PNU concentrations above 5000 for weight per volume of 1:200 we suggest a maintenance dose of 5000 PNU.

Intralymphatic immunotherapy with tyrosine-adsorbed allergens: a double-blind, placebo-controlled trial

Background Most previous studies used aluminum hydroxide-absorbed allergen extracts in evaluating the potential therapeutic roles of intralymphatic allergen-specific immunotherapy (ILAIT). In this study, we evaluated the therapeutic efficacy and safety of ILAIT with L-tyrosine-adsorbed allergen extracts of Dermatophagoides farinae, D. pteronyssinus, cat, dog, or mixtures thereof, in patients with allergic rhinitis induced by these allergens. Methods In this randomized, double-blind, placebo-controlled trial, study subjects received three intralymphatic injections of L-tyrosine-adsorbed allergen extracts (active group) or saline (placebo group) at 4-week intervals. Results Although ILAIT reduced daily medication use and skin reactivity to HDM and cat allergens at 4 months after treatment, overall symptom score on a visual analog scale (VAS), sinonasal outcome test-20 (SNOT-20), rhinoconjunctivitis quality of life questionnaire (RQLQ), daily symptom score (dSS), daily medication score (dMS), daily symptom medication score (dSMS), nasal reactivity to HDM allergen, and basophil activity to HDM, cat, and dog allergens at 4 months and 1 year after treatment were similar between the treatment and control groups. Intralymphatic injection was more painful than a venous puncture, and pain at the injection site was the most frequent local adverse event (12.8%); dyspnea and wheezing were the most common systemic adverse events (5.3%). Conclusions ILAIT with L-tyrosine-adsorbed allergen extracts does not exhibit profound therapeutic efficacy in allergic rhinitis and can provoke moderate-to-severe systemic reactions and cause pain at the injection site. Trial registration: clinicaltrials.gov: NCT02665754; date of registration: 28 January 2016