Rye Grass Pollen Research Articles

Subcutaneous immunotherapy for bee venom allergy induces epitope spreading and immunophenotypic changes in allergen-specific memory B cells

Allergen immunotherapy (AIT) is the only disease-modifying treatment for allergic disorders. We have recently discovered that allergen-specific memory B cells (Bmem) are phenotypically altered after 4 months of sublingual AIT for ryegrass pollen allergy. Whether these effects are shared with subcutaneous allergen immunotherapy (SCIT) and affect the epitope specificity of Bmem remain unknown. The study aimed to evaluate the phenotype and antigen receptor sequences of Bmem specific to the major bee venom (BV) allergen Api m 1 before and after ultra-rush SCIT for BV allergy. Recombinant Api m 1 protein tetramers were generated to evaluate basophil activation in a cohort of individuals with BV allergy before and after BV SCIT. Comprehensive flow cytometry was performed to evaluate and purify Api m 1-specific Bmem. Immunoglobulin genes from single Api m 1-specific Bmem were sequenced and structurally modeled onto Api m 1. SCIT promoted class switching of Api m 1-specific Bmem to IgG2 and IgG4 with increased expression of CD23 and CD29. Furthermore, modeling of Api m 1-specific immunoglobulin from Bmem identified a suite of possible new and diverse allergen epitopes on Api m 1 and highlighted epitopes that may preferentially be bound by immunoglobulin after SCIT. AIT induces shifting of epitope specificity and phenotypic changes in allergen-specific Bmem.

RNA sequencing of single allergen-specific memory B cells after grass pollen immunotherapy: Two unique cell fates and CD29 as a biomarker for treatment effect.

Sublingual immunotherapy (SLIT) for grass pollen allergy can modify the natural history of allergic rhinitis and is associated with increased allergen-specific IgG4 . IgG4 competitively inhibits functional IgE on the surface of effector cells, such as mast cells and basophils, from binding to allergens. To further understand the important role memory B-cell (Bmem) responses play in mediating the beneficial effects of SLIT, we assessed changes in allergen-specific Bmem subsets induced by SLIT for grass pollen allergy. Blood samples were collected twice outside the pollen season from twenty-seven patients with sensitization to ryegrass pollen (RGP; Lolium perenne) and seasonal rhinoconjunctivitis. Thirteen received 4-month pre-seasonal SLIT for grass pollen allergy, and 14 received standard pharmacotherapy only. Single-cell RNA sequencing was performed on FACS-purified Lol p 1-specific Bmem before and after SLIT from four patients, and significant genes were validated by flow cytometry on the total cohort. Four months of SLIT increased RGP-specific IgE and IgG4 in serum and induced two Lol p 1-specific Bmem subsets with unique transcriptional profiles. Both subsets had upregulated expression of beta 1 integrin ITGB1 (CD29), whereas IGHE (IgE), IGHG4 (IgG4 ), FCER2 (CD23), and IL13RA1 were upregulated in one subset. There was an increase in the proportion of Lol p 1+ Bmem expressing surface IgG4 , CD23, and CD29 after SLIT. A clinically successful 4months course of SLIT for grass pollen allergy induces two transcriptionally unique Bmem fates. Associated changes in surface-expressed proteins on these Bmem subsets can be used as early biomarkers for treatment effects.

Epidemic thunderstorm asthma

Epidemic thunderstorm asthma

5-grass-pollen SLIT effectiveness in seasonal allergic rhinitis: Impact of sensitization to subtropical grass pollen.

BackgroundTemperate grass (eg, ryegrass) pollen is a major driver of seasonal allergic rhinitis (SAR) and asthma risks, including thunderstorm asthma. Data for the effectiveness of temperate grass pollen allergen immunotherapy (AIT) in SAR patients from the southern hemisphere, who are frequently polysensitized to subtropical grass pollens, are limited. The 300 IR 5-grass pollen sublingual immunotherapy tablet (300 IR 5-grass SLIT) is known to be effective in polysensitized SAR patients with primary allergy to temperate grasses, however, the influence of polysensitization to subtropical grass pollen on treatment responses has yet to be specifically addressed. Key aims of this study were to measure patient treatment satisfaction during 300 IR 5-grass SLIT treatment and evaluate how polysensitization to subtropical grass pollens affects treatment responses.MethodsA prospective observational study was conducted in 63 patients (aged ≥5 years) in several temperate regions of Australia prescribed 300 IR 5-grass SLIT for SAR over 3 consecutive grass pollen seasons. Ambient levels of pollen were measured at representative sites. Patient treatment satisfaction was assessed using a QUARTIS questionnaire. Rhinoconjunctivitis Total Symptom Score (RTSS) and a Hodges-Lehmann Estimator analysis was performed to evaluate if polysensitization to subtropical grass pollen affected SAR symptom intensity changes during SLIT.ResultsA diagnosis of ryegrass pollen allergy was nearly universal. There were 74.6% (47/63) polysensitized to subtropical and temperate grass pollens. There were 23.8% (15/63) monosensitized to temperate grass pollens. From the first pollen season, statistically significant improvements occurred in SAR symptoms compared with baseline in both monosensitized and polysensitized patients, particularly in those polysensitized (P = 0.0297). Improvements in SAR symptoms were sustained and similar in both groups in the second and third pollen seasons, reaching 70–85% improvement (P < 0.01). Polysensitized patients from both northerly and southerly temperate regions in Australia showed similar improvements. Grass pollen counts in both regions were consistently highest during springtime.Conclusions300 IR 5-grass SLIT is effective in a real-life setting in SAR patients in the southern hemisphere with primary allergy to temperate grass pollen and predominantly springtime grass pollen exposures. Importantly, SLIT treatment effectiveness was irrespective of the patient's polysensitization status to subtropical grass pollens.

Role of Ipratropium bromide in management of Thunderstorm asthma

Epidemic thunderstorm asthma has been reported to have occurred around twenty times over the past three decades in locations around the world. Thunderstorm asthma events are characterized by a significant increase in asthma presentations, which on occasion can overwhelm local medical services and result in fatalities. Thunderstorm asthma (TA) typically presents during an aeroallergen season in individuals, sensitized to perennial rye grass pollen (RGP) in Australia, in combination with meteorological factors such as thunderstorms and lightning activity. Short acting beta agonist (SABA) only treatment is sub-optimal therapy for prevention of asthma exacerbations. The combined treatment includes inhaled corticosteroids (ICS) and SABA but is found to be contentious. So the present review focuses on suitable alternative, short acting muscarinic antagonist (SAMA), Ipratropium bromide and its efficacy on the management of allergic asthma. Salbutamol induces bronchodilation rapidly but it elicits profound cardiovascular event as the side effects. Meanwhile, ipratropium also has equivalent effect of salbutamol with low side effect profile. Ipratropium also minifies the asthmatic response to grass pollen, allergen induced bronchoconstriction. Further, it also reduces allergen induced early and late asthmatic response and also inhibits the response towards histamine inhalation. In this regard, ipratropium may be considered as a suitable agent in the management of thunderstorm asthma and future trials are highly warranted. Keywords: Thunderstorm asthma, grass pollen, rye grass, short acting beta agonist, Ipratropium bromide

Managing Exacerbations in Thunderstorm Asthma: Current Insights.

Epidemic thunderstorm asthma (ETSA) occurs following a thunderstorm due to the interaction of environmental and immunologic factors. Whilst first reported in the 1980s, the world’s largest event in Melbourne, Australia, on November 21, 2016 has led to a wealth of clinical literature seeking to identify its mechanisms, susceptibility risk factors, and management approaches. Thunderstorm asthma (TA) typically presents during an aeroallergen season in individuals sensitized to perennial rye grass pollen (RGP) in Australia, or fungus in the United Kingdom, in combination with meteorological factors such as thunderstorms and lightning activity. It is now well recognized that large pollen grains, which usually lodge in the upper airway causing seasonal allergic rhinitis (SAR), are ruptured during these events, leading to sub-pollen particles respirable to the lower respiratory tract causing acute asthma. The identified risk factors of aeroallergen sensitization, specifically to RGP in Australians with a history of SAR, and individuals born in Australia of South-East Asian descent as a risk factor for TA has been key in selecting appropriate patients for preventative management. Moreover, severity-determining risk factors for ETSA-related asthma admission or mortality, including pre-existing asthma or prior hospitalization, poor inhaled corticosteroid adherence, and outdoor location at the time of the storm are important in identifying those who may require more aggressive treatment approaches. Basic treatments include optimizing asthma control and adherence to inhaled corticosteroid therapy, treatment of SAR, and education regarding TA to increase recognition of at-risk days. Precision treatment approaches may be more beneficial in select individuals, including the use of allergen immunotherapy and even biologic treatment to mitigate asthma severity. Finally, we discuss the importance of environmental health literacy in the context of concerns surrounding the increased frequency of ETSA due to climate change and its implications for the frequency and severity of future events.

CytoBas: Precision component-resolved diagnostics for allergy using flow cytometric staining of basophils with recombinant allergen tetramers.

BackgroundDiagnostic tests for allergy rely on detecting allergen‐specific IgE. Component‐resolved diagnostics incorporate multiple defined allergen components to improve the quality of diagnosis and patient care.ObjectiveTo develop a new approach for determining sensitization to specific allergen components that utilizes fluorescent protein tetramers for direct staining of IgE on blood basophils by flow cytometry.MethodsRecombinant forms of Lol p 1 and Lol p 5 proteins from ryegrass pollen (RGP) and Api m 1 from honeybee venom (BV) were produced, biotinylated, and tetramerized with streptavidin‐fluorochrome conjugates. Blood samples from 50 RGP‐allergic, 41 BV‐allergic, and 26 controls were incubated with fluorescent protein tetramers for flow cytometric evaluation of basophil allergen binding and activation.ResultsAllergen tetramers bound to and activated basophils from relevant allergic patients but not controls. Direct fluorescence staining of Api m 1 and Lol p 1 tetramers had greater positive predictive values than basophil activation for BV and RGP allergy, respectively, as defined with receiver operator characteristics (ROC) curves. Staining intensities of allergen tetramers correlated with allergen‐specific IgE levels in serum. Inclusion of multiple allergens coupled with distinct fluorochromes in a single‐tube assay enabled rapid detection of sensitization to both Lol p 1 and Lol p 5 in RGP‐allergic patients and discriminated between controls, BV‐allergic, and RGP‐allergic patients.ConclusionOur novel flow cytometric assay, termed CytoBas, enables rapid and reliable detection of clinically relevant allergic sensitization. The intensity of fluorescent allergen tetramer staining of basophils has a high positive predictive value for disease, and the assay can be multiplexed for a component‐resolved and differential diagnostic test for allergy.

English

The practices of using isolation and distance in the seed production of open pollinated crops are fundamental concepts to ensure seed purity. We uniquely examined the effectiveness of replacing isolation plots for seed production and grass breeding with different sizes of novel nonwoven synthetic fabric pollination control tents (PCTs). Two fabrics, DWB10 and DWB24, were used along with multiple genotypes of tall fescue at Ardmore, Burneyville and Gene Autry locations in Oklahoma, USA during 2018 and 2019. Treatment effects were consistently significant in both years, but location differences were more pronounced in 2019. Interactions of treatments with locations or genotypes were not predominant. The two tent fabrics, generally, performed equally well for various traits in both years. Tent performance for both fabrics was particularly superior over control for various traits in 2019 (e.g., DWB10 tent showed a 36% increase for seed yield (SY) over the control). Introduction of fans in tents for increasing pollen flow in 2019 was not advantageous as it reduced the SY by 23%. The average temperature within tents was higher with lower average humidity than the control producing a microclimate for good yield and disease free seeds. The final germination (%) of seeds from tents and controls at 21 days was high and not much different with a minimum overall germination of 89% at Burneyville in 2018. There was no evidence of pollen contamination from tetraploid ryegrass pollen in any of the tent fabrics. Bad weather in 2018 affected the sturdiness of tents, but modifications in 2019 corrected all such mishaps. Further improvements in the structures, design and cover have since been made for field exploitation of technology in grass improvement and seed multiplication. Key words: Ryegrass, fescue grass, pollination control tents, nonwoven fabrics. &nbsp

Induction of IgG2 and IgG4 B-cell memory following sublingual immunotherapy for ryegrass pollen allergy.

BackgroundWhile treatment for atopic rhinitis is aimed mostly to relieve symptoms, only allergen‐specific immunotherapy (AIT) is targeted to modify the natural history of allergic diseases. This results in sustained clinical tolerance, even when treatment has stopped. The immunomodulatory effects of AIT are attributed mainly to increased regulatory T‐cell function and increased allergen‐specific IgG4, yet little is known about the effect on the memory B‐cell compartment.ObjectiveWe aimed to examine the effects of AIT on the IgE‐ and IgG subclass‐expressing memory B cells.MethodsWe recruited 29 patients with atopic seasonal rhinoconjunctivitis and performed a longitudinal analysis of the peripheral immune compartment before, during, and after sublingual immunotherapy (SLIT) for allergy to temperate grass pollen, predominantly to ryegrass pollen (RGP; Lolium perenne). Using flow cytometry on peripheral blood mononuclear cells and serum immunoassays, we analyzed the effects of a 4 months preseasonal treatment regimen comprising two or three courses in consecutive years on circulating IgE+ and IgG+ memory B cells and allergen‐specific Ig levels.ResultsSLIT increased RGP‐specific serum IgG2 and IgG4, as well as the frequencies of IgG2 + and IgG4 + memory B cells, whereas no effect was observed on the IgE+ memory B‐cell compartment. Furthermore, SLIT enhanced proportions of regulatory T cells specific to RGP. These changes were associated with clinical improvement.ConclusionOur data provide evidence for immunological effects of SLIT on B‐cell memory. Skewing responses toward IgG2 and IgG4 subclasses might be a mechanism to suppress IgE‐mediated allergic responses.

Thunderstorm-triggered asthma: what we know so far.

Thunderstorm-triggered asthma (TA) is the occurrence of acute asthma attacks immediately following a thunderstorm. Epidemics have occurred across the world during pollen season and have the capacity to rapidly inundate a health care service, resulting in potentially catastrophic outcomes for patients. TA occurs when specific meteorological and aerobiological factors combine to affect predisposed patients. Thunderstorm outflows can concentrate aeroallergens, most commonly grass pollen in TA, at ground level to release respirable allergenic particles after rupture by osmotic shock related to humidity and rainfall. Inhalation of high concentrations of these aeroallergens by sensitized individuals can induce early asthmatic responses which are followed by a late inflammatory phase. Other environmental factors such as rapid temperature change and agricultural practices contribute to the causation of TA. The most lethal TA event occurred in Melbourne, Australia, in 2016. Studies on the affected individuals found TA to be associated with allergic rhinitis, ryegrass pollen sensitization, pre-existing asthma, poor adherence to inhaled corticosteroid preventer therapy, hospital admission for asthma in the previous year and outdoor location at the time of the storm. Patients without a prior history of asthma were also affected. These factors are important in extending our understanding of the etiology of TA and associated clinical indicators as well as possible biomarkers which may aid in predicting those at risk and thus those who should be targeted in prevention campaigns. Education on the importance of recognizing asthma symptoms, adherence to asthma treatment and controlling seasonal allergic rhinitis is vital in preventing TA. Consideration of allergen immunotherapy in selected patients may also mitigate risk of future TA. Epidemic TA events are predicted to increase in frequency and severity with climate change, and identifying susceptible patients and preventing poor outcomes is a key research and public health policy priority.

СЕНСИБИЛИЗАЦИЯ ДЕТЕЙ С БРОНХИАЛЬНОЙ АСТМОЙ. АНАЛИЗ 10-ЛЕТНЕЙ ДИНАМИКИ

Вackground. Sensitization to allergens is a major factor contributing to the development of bronchial asthma, maintenance of its symptoms and risk of its persistence into adulthood. Objective: to evaluate the frequency of sensitization to allergens in children with bronchial asthma over a 10-year period (2006-2007–2016-2017). Material and methods. According to the results of skin testing (prick test), performed in children with bronchial asthma, the spectrum of cause-significant allergens (2006–2007: ntests=428 (household and epidermal – 178, pollen – 79, food – 171) and 2016–2017: ntests = 453 (domestic and epidermal – 195, pollen – 78, food – 180) was analyzed. Results. It was established that in children with asthma, household allergens (57.3%, CI: 49.96–64.34%) were the leading ones in the spectrum of inhalation sensitization. In the structure of household sensitization the first ranking places were occupied by allergens of the tick D. pteronyssinus (60.51%, CI: 53.51–67.11%), domestic (56.41%, CI: 49.39–63.18%) and library dust (53.85%, CI: 46.84–60.7%); in the structure of epidermal sensitization – by dog (32.31%, CI: 26.13–39.17%) and cat hair allergens (30.26%, CI: 24.23–37.05%); in the structure of pollen sensitization – by cock's-foot grass (44.87%, CI: 34.33–55.89%), perennial ryegrass (43.59%, CI: 33.14–54.64), rye (39.74%, CI: 29.6–50.85) and foxtail grass pollen allergens (39.74%, CI: 29.6–50.85%); in the structure of food sensitization – by wheat flour (38.89%, CI: 32.07–46.18%), cow's milk (37.22%, CI: 30.94–44.49%) and chicken meat allergens (37.22%, CI: 30.94–44.49% ). During a 10-year period, the children with bronchial asthma had a high prevalence of household and epidermal sensitization; an increase in the frequency of sensitization to household (p=0.0000), epidermal (p=0.0012) and food allergens (p=0.0000) was observed; there was an increase in the number of positive skin tests to allergens of dog (p=0.0037) and cat hair (p=0.0000), feather pillows (p=0.0000), library dust (p=0.0000), tick D. pteronyssinus (p=0.0000) and perennial ryegrass pollen (p=0.0001) as well as most foods (p&lt;0.05). Gender features of the structure and dynamics of sensitization to allergens were established. Conclusions. The obtained results should be taken into account when conducting treatment and rehabilitation measures aimed at achieving control of bronchial asthma in children and its prevention in those at risk.

Who's at risk of thunderstorm asthma? The ryegrass pollen trifecta and lessons learnt from the Melbourne thunderstorm epidemic.

The Melbourne thunderstorm asthma epidemic in November 2016 was unprecedented in scale and impact. We systematically reviewed our hospital's patients with thunderstorm asthma to identify key risk factors. Of 85 adult patients assessed, the majority (60%) had no prior diagnosis of asthma. However, allergic rhinitis during the grass pollen season was almost universal (99%), as were ryegrass pollen sensitization (100%) and exposure to the outdoor environment during the thunderstorm (94%). Airborne pollen levels on the thunderstorm day were extreme. We conclude that ryegrass pollen sensitization, clinical allergic rhinitis, and acute allergen exposure constitute a risk-factor 'trifecta' for thunderstorm asthma.

The Role of Mesoscale-Convective Processes in Explaining the 21 November 2016 Epidemic Thunderstorm Asthma Event in Melbourne, Australia

AbstractA major thunderstorm asthma epidemic struck Melbourne and surrounding Victoria, Australia, on 21 November 2016, which led to multiple deaths, a flood of residents seeking medical attention for respiratory problems, and an overwhelmed emergency management system. This case day had all the classic ingredients for an epidemic, including high rye grass pollen concentrations, a strong multicellular thunderstorm system moving across the region, and a large population of several million people in the vicinity of Melbourne. A particular characteristic of this event was the strong, gusty winds that likely spread the pollen grains and/or allergenic contents widely across the region to increase population exposure. This exploratory case study is the first to examine the usefulness of low-to-middle-atmospheric thermodynamic information for anticipating epidemic thunderstorm asthma outbreaks by allowing the forecast of strong downdraft winds. The authors investigated the utility of several mesoscale products derived from atmospheric soundings such as downdraft convective available potential energy (DCAPE) and indices for predicting surface wind gusts such as microburst wind speed potential index (MWPI) and a wind gust index (GUSTEX). These results indicate that DCAPE levels reached “high” to “very high” thresholds for strong downdraft winds in the lead-up to the thunderstorm, and the MWPI and GUSTEX indices accurately predicted the high maximum surface wind observations. This information may be useful for diagnostic and prognostic assessment of epidemic thunderstorm asthma and in providing an early warning to health practitioners, emergency management officials, and residents in affected areas.

Is California Drought Affecting Population IgE Levels?

We noted that the 95thpercentile for some allergen IgE levels varied in different months, and that these varied in annual cycles. Data indicated that the population’s IgE levels for rye grass pollen were lower in recent years than in prior years. Data were obtained for specific IgE testing from a major southern California medical organization. Rye grass results obtained within a given month were ranked to determine percentiles. These showed cyclic variation. Values for 2013-2015 were significantly below a projection based on 2009-2012. California is experiencing a prolonged years-long drought, so we correlated the population rye grass IgE levels with southern California rainfall data. Population levels for rye grass IgE were lowest in December-January of each year, rising rapidly to a maximum in May-June and then tapering off. Rainfall for southern California was less regular but occurs predominantly in October-March. Population rye grass IgE levels correlated to precipitation occurring four months prior. This held for seasonal variations and for variations between wet and drought years. Similar trends were seen with other allergens but not with perennial allergens (e.g. cat dander). Population levels of rye grass IgE levels were shown to correlate to precipitation occurring four months prior. During the current California drought the peaks of rye grass IgE were diminished in parallel to the decreased rainfall, with population IgE levels dropping to about 74% of the normal level. Population IgE levels and likelihood of symptomatic patients may be anticipated based on preceding rainfall levels.

Acupuncture for seasonal allergic rhinitis: a randomized controlled trial

BackgroundSeasonal allergic rhinitis (SAR) is a common condition with relatively high prevalence in Australia. It causes a significant impact on sufferers' quality of life (QoL). Meta-analysis has shown that the efficacy of acupuncture for SAR is uncertain. ObjectiveTo evaluate the efficacy and safety of 12 sessions of acupuncture treatment during 4 weeks for SAR in a randomized, subject- and assessor-blinded, sham-controlled trial conducted during the pollen seasons in 2009 through 2011 in Melbourne. MethodsPatients diagnosed with SAR and confirmed allergic to rye grass pollen were randomly allocated to receive real acupuncture (RA) or sham acupuncture (SA) treatment. RA was delivered manually, whereas SA involved superficial needling at non-acupoints without additional stimulation. Severity of SAR symptoms was the primary outcome measurement. Secondary outcomes were QoL, global change, SAR-related medication usage, and adverse events. Analysis of covariance using pollen count as a covariate was used to analyze outcome data. ResultsA total of 175 participants were included in this trial. RA was significantly better than SA for decreasing SAR symptom severity (sneezing, mean difference −0.28, 95% confidence interval −0.51 to −0.05; itchiness of ears and palate, mean difference −0.40, 95% confidence interval −0.69 to −0.11) at the end of treatment and improving participants' QoL at the end of the treatment and follow-up phases. Furthermore, the acupuncture treatment was safe and well tolerated. ConclusionFour weeks of acupuncture treatment is a safe and effective option for clinical management of SAR in the Melbourne area for patients' symptom relief and QoL improvement.

Clinical validation of controlled grass pollen challenge in the Environmental Exposure Unit (EEU).

RationaleThe Environmental Exposure Unit (EEU), a controlled allergen exposure model of allergic rhinitis (AR), has traditionally utilized ragweed pollen. We sought to clinically validate the use of grass pollen in the EEU.MethodsHealthy volunteers with a history of AR symptoms during grass pollen season and supportive skin test responses attended the EEU for 3 hrs of rye grass pollen exposure (Lolium Perenne). Non-atopic controls were also recruited. Participants assessed individual rhinoconjunctivitis symptoms to generate Total Nasal Symptom Score (TNSS; max 12) and Total Symptom Score (TSS; max 24) and recorded Peak Nasal Inspiratory Flow (PNIF) q30min while in the EEU. Participants returned the following day for an additional 3 hrs of pollen exposure. Two separate groups allowed for the exploration of lower vs. higher pollen concentrations and subsequent effects on symptoms.Results78 participants were screened, of whom 39 were eligible and attended the 2x3h EEU visits, plus 8 non-atopic controls. Mean TSS, TNSS and PNIF values amongst participants in the higher pollen concentration group (target 3500 grains/m3) after the first 3 hr exposure were 18.9, 9.7 and 68 L/min, respectively. In comparison, mean TSS, TNSS and PNIF values in the lower pollen concentration (2500 grains/m3) group were only 13.3, 7.6, and 82 L/min, respectively. The subsequent day of pollen exposure did not appreciably alter the maximal TSS/TNSSs, but rather resulted in a more rapid onset of symptomatology, with higher mean scores at the 30 min, 60 min and 90 min timepoints. The non-atopic controls remained asymptomatic.ConclusionsThis study provides clinical validation of the ability to generate allergic rhinoconjunctivitis symptoms amongst grass-allergic individuals in the EEU.

Do lipids influence the allergic sensitization process?

Allergic sensitization is a multifactorial process that is not only influenced by the allergen and its biological function per se but also by other small molecular compounds, such as lipids, that are directly bound as ligands by the allergen or are present in the allergen source. Several members of major allergen families bind lipid ligands through hydrophobic cavities or electrostatic or hydrophobic interactions. These allergens include certain seed storage proteins, Bet v 1–like and nonspecific lipid transfer proteins from pollens and fruits, certain inhalant allergens from house dust mites and cockroaches, and lipocalins. Lipids from the pollen coat and furry animals and the so-called pollen-associated lipid mediators are codelivered with the allergens and can modulate the immune responses of predisposed subjects by interacting with the innate immune system and invariant natural killer T cells. In addition, lipids originating from bacterial members of the pollen microbiome contribute to the outcome of the sensitization process. Dietary lipids act as adjuvants and might skew the immune response toward a TH2-dominated phenotype. In addition, the association with lipids protects food allergens from gastrointestinal degradation and facilitates their uptake by intestinal cells. These findings will have a major influence on how allergic sensitization will be viewed and studied in the future.

Immunomodulatory Effects Of Rye Grass Pollen Allergen Lol p 5 On The Prostaglandin E2 Pathway and Kallikrein-Kinin System Of Respiratory Epithelial Cells

Several important aeroallergens are known to modulate respiratory epithelial (RE) function. The rye grass pollen Group 5 allergen is a significant contributor to pollen allergy but its immunomodulatory effects on RE function are unknown. Rye grass pollen allergen rLol p 5 and its N- and C-terminal domains were expressed in E. coli. Physicochemical studies were conducted using SDS-PAGE, native-PAGE, HPLC, circular dichroism and Phyre2 modelling. Allergenicity was determined by ELISA and immunoblot, and ribonuclease activity by enzyme assay. RE IL-8 release was examined using ELISA and A549, 16HBE14sigma- and Detroit562 cell lines. mRNA level expression of enzymes/proteins associated with the prostaglandin E2 (PGE2) pathway and kallikrein-kinin system (KKS) by RE cells were determined using RT-PCR. 3D-modelling showed rLol p 5 to be structurally similar to Timothy grass pollen Group 5 allergen; circular dichroism analysis showed heat stable proteins with a predominance of α-helices and coils, consistent with the 3D structures. HPLC and native PAGE indicated trimerization (mature and N-terminal domain) and dimerization (C-terminal domain). Each protein was enzymatically active, and reacted with IgE from seven rye grass pollen sensitive patients. All three cell lines released IL-8, and A549 cells showed PGE2 release. RT-PCR with A549 showed up-regulation of COX-2, mPGES-1, mPGES-2 and cPGES in the PGE2 pathway, and gC1qR, UPAR, UPA, HSP90α and PAI associated with the KKS. The ribonuclease Lol p 5 and its component domains were allergenic, existed as oligomers, induced IL-8 and PGE2 and up-regulated proinflammatory PGE2 and KKS pathways by, as yet, unknown mechanisms.

Pollen

Pollen

TLR ligands of ryegrass pollen microbial contaminants enhance Th1 and Th2 responses and decrease induction of Foxp3hi regulatory T cells

Microbial contamination of grass pollens could affect sensitization, subsequent allergic response, and efficacy of allergen-specific immunotherapy. We investigated whether bacterial immunomodulatory substances can direct PBMC responses of allergic and nonatopic subjects against ryegrass pollen (RGP) toward Th1, Th2, or regulatory T (Treg) cells. Aqueous extracts of RGP with high or low LPS were fractionated into large and small molecular weight (MW) components by diafiltration. CFSE-labeled PBMCs from allergic and nonatopic subjects were stimulated with RGP extracts (RGPEs) and analyzed for cytokine secretion and T-cell responses. High LPS RGPE increased IFN-γ(+) Th1 and IL-4(+) Th2 effector cell induction and consistently decreased CD4(+) Foxp3(hi) Treg-cell induction. IL-10-producing T-cell frequency was unaltered, but IL-10 secretion was increased by high LPS RGPE. RGPE-stimulation of TLR-transfected cell lines revealed that high LPS pollen also contained a TLR2-ligand, and both batches a TLR9-ligand. Beta-1,3-glucans were detected in large and small MW fractions and were also T-cell stimulatory. In conclusion, coexposure to allergen and proinflammatory microbial stimuli does not convert an established Th2- into a Th1-response. Instead, proinflammatory responses are exacerbated and Foxp3(hi) Treg-cell induction is decreased. These findings show that adjuvants for specific immunotherapy should enhance Treg cells rather than target immune deviation from Th2 to Th1.