Allergenic relevance of Cupressus arizonica pollen extract and biological characterization of the allergoid

Determination of allergenic load and pollen count of Cupressus arizonica pollen by flow cytometry using Cup a1 polyclonal antibody

BACKGROUND

There is an increase in the incidence of pollen related allergy, thus information on pollen schedules would be a great asset for physicians to improve the clinical care of patients. Like cypress pollen sensitization shows a high prevalence among the causes of allergic rhinitis, and therefore it is of interest to use it like a model of study, distinguishing cypress pollen, pollen count, and allergenic load level. In this work, we use a flow cytometry based technique to obtain both Cupressus arizonica pollen count and allergenic load, using specific rabbit polyclonal antibody Cup a1 and its comparison with optical microscopy technique measurement.

METHODS

Airborne samples were collected from Burkard Spore-Trap and Burkard Cyclone Cupressus arizonica pollen was studied using specific rabbit polyclonal antibody Cup a1, labeled with AlexaFluor(®) 488 or 750 and analysed by Flow Cytometry in both an EPICS XL and Cyan ADP cytometers (Beckman Coulter(®) ). Optical microscopy study was realized with a Leica optical microscope. Bland and Altman was used to determine agreement between both techniques measured.

RESULTS

We can identify three different populations based on rabbit polyclonal antibody Cup a1 staining. The main region (44.5%) had 97.3% recognition, a second region (25%) with 28% and a third region (30.5%) with 68% respectively. Immunofluorescence and confocal microscopy showed that main region corresponds to whole pollen grains, the second region are pollen without exine and the third region is constituted by smaller particles with allergenic properties. Pollen schedule shows a higher correlation measured by optical microscopy and flow cytometry in the pollen count with a P-value: 0.0008 E(-2) and 0.0002 with regard to smaller particles, so the Bland and Altman measurement showed a good correlation between them, P-value: 0.0003.

CONCLUSION

Determination of pollen count and allergenic load by flow cytometry represents an important tool in the determination of airborne respiratory allergens. We showed that not only whole pollen but also smaller particles could induce allergic sensitization. This is the first study where flow cytometry is used for calculating pollen counts and allergenic load.

A modified protocol for RNA isolation from high polysaccharide containing Cupressus arizonica pollen. Applications for RT-PCR and phage display library construction

RNA isolation is the first step in the study of gene expression and recombinant protein production. However, the isolation of high quantity and high-quality RNA from tissues containing large amounts of polysaccharides has proven to be a difficult process. Cupressus arizonica pollen, in addition to containing high polysaccharide levels, is a challenging starting material for RNA isolation due to the roughness of the pollen grain's walls. Here, we describe an improved technique for RNA isolation from C. arizonica pollen grains. The protocol includes a special disruption and homogenization process as well as a two-step modified RNA isolation technique which consists of an acid phenol extraction followed by a final cleanup using a commercial kit. Resulting RNA proved to be free of contaminants as determined by UV spectrophotometry. The quality of the RNA was analyzed on a bioanalyzer and showed visible 25S and 18S bands. This RNA was successfully used in downstream applications such as RT-PCR and phage display library construction.

Desloratadine for the treatment of cypress pollen-induced allergic rhinitis

BACKGROUND

Few studies have been conducted to assess treatment options for patients with sensitivities to cypress pollens, important triggers of allergic rhinitis (AR) in the Mediterranean region.

OBJECTIVE

To evaluate the effect of desloratadine, a second-generation antihistamine, on AR symptoms caused by cypress pollens native to France.

METHODS

Adults (N=233) with symptomatic cypress pollen allergies were randomized to receive desloratadine, 5 mg, or placebo daily for 15 days during 2 consecutive cypress pollen seasons. The primary end point was the percentage change from baseline in morning total nasal symptom scores on day 14; secondary assessments included total symptom score, peak nasal inspiratory flow, the Rhinoconjunctivitis Quality of Life Questionnaire, and global response to therapy.

RESULTS

On day 14, the desloratadine group had a significantly greater percentage decrease in total nasal symptom score vs the placebo group (-40% vs. -30%; P < .04). Similarly, on day 14, there was a 47% and 37% respective decrease in total symptom score (P = .01). Mean peak nasal inspiratory flow scores showed numeric, albeit not statistically significant, improvements from baseline through day 14 with desloratadine. A significantly greater improvement in Rhinoconjunctivitis Quality of Life Questionnaire scores occurred with desloratadine vs placebo on day 14 (-1.4 vs. -0.9; P = .004). The mean global response to therapy was better with desloratadine vs placebo (3.4 vs. 3.9; P = .004). The adverse event rate was similar in both groups.

CONCLUSION

Desloratadine is efficacious and safe for the treatment of AR induced by cypress pollens; it also improved disease-related quality of life.

Immunology

The concept of forbidden foods that should not be eaten goes back to the Garden of Eden and apart from its religious meanings it may also have foreshadowed the concept of foods that can provoke adverse reactions. Thus we could say that allergic diseases have plagued mankind since the beginning of life on earth. The prophet Job was affected by a condition that following the rare symptoms described by the Holy Bible might be identified as a severe form of atopic dermatitis (AD). The earliest record of an apparently allergic reaction is 2621 B.C., when death from stinging insects was first described by hieroglyphics carved into the walls of the tomb of Pharaoh Menes depicting his death following the sting of a wasp. In 79 A.D., the death of the Roman admiral Pliny the Elder was ascribed to the SO₂-rich gases emanating from the eruption of Mount Vesuvius. Hippocrates (460–377 B.C.) was probably the first to describe how cow’s milk (CM) could cause gastric upset and hives, proposing dietetic measures including both treatment and prevention for CM allergy.

Artemisia vulgaris pollen allergoids digestibility in the simulated conditions of the gastrointestinal tract

Chemically modified allergens (allergoids) have found use in both traditional and novel forms of immunotherapy of allergic disorders. Novel forms of immunotherapy include local allergen delivery, via the gastrointestinal tract. This study conveys the gastrointestinal stability of three types of mugwort pollen allergoids under simulated conditions of the gut. Allergoids of the pollen extract of Artemisia vulgaris were obtained by means of potassium cyanate, succinic and maleic anhydride. Gastrointestinal tract conditions (saliva, and gastric fluid) were simulated in accordance with the EU Pharmacopoeia. The biochemical and immunochemical properties of the derivatives following exposure to different conditions were monitored by determining the number of residual amino groups with 2,4,6-trinitrobenzenesulfonic acid, SDS PAGE, immunoblotting and inhibition of mugwort-specific IgE. Exposure to saliva fluid for 2 min did not influence the biochemical and immunochemical properties of the derivatives. In the very acidic conditions of the simulated gastric fluid, the degree of demaleylation and desuccinylation, even after 4 h exposure, was low, ranging from 10 to 30 %. The digestion patterns with pepsin proceeded rapidly in both the unmodified and modified samples. In all four cases, a highly resistant IgE-binding protein the Mwof which was about 28-35 kD, was present. Within the physiological conditions, no new IgE binding epitopes were revealed, as demonstrated by immunoblot and CAP inhibition of the mugwort specific IgE binding. An important conclusion of this study is the stability of the modified derivatives in the gastrointestinal tract of patients, within physiological conditions. The means that they are suitable for use in much higher concentrations in local forms of immunotherapy than unmodified ones.

Allergy to cypress pollen

Although Cupressus sempervirens has been spread over southern Europe since antiquity, cypress pollen allergy has not been reported until 1945. In France, the very first case reports were published in 1962. Since then, the prevalence of cypress pollinosis seems to demonstrate an upward trend, concomitantly with the increased use of cypress trees as ornamental plants, as wind breaks and as hedges. Hyposensitization, using improved pollen extracts, is increasingly prescribed. Besides, prevention measures begin to be implemented. Such measures include avoidance of planting new cypress trees, especially near human populations' centres, trimming of cypress hedges before the pollination season and agronomical research for hypoallergenic trees. Altogether, such new developments in cypress allergy deserve an update review.

Transition from a Botanical to a Molecular Classification in Tree Pollen Allergy: Implications for Diagnosis and Therapy

Tree pollens are among the most important allergen sources. Allergic cross-reactivity to pollens of trees from various plant orders has so far been classified according to botanical relationships. In this context, cross-reactivities to pollens of trees of the Fagales order (birch, alder, hazel, hornbeam, oak, chestnut), fruits and vegetables, between pollens of the Scrophulariales (olive, ash, plantain, privet, lilac) and pollens of the Coniferales (cedar, cypress, pine) are well established. The application of molecular biology methods for allergen characterization has revealed the molecular nature of many important tree pollen allergens. We review the spectrum of tree pollen allergens and propose a classification of tree pollen and related allergies based on major allergen molecules instead of botanical relationships among the allergenic sources. This molecular classification suggests the major birch pollen allergen, Bet v 1 as a marker for Fagales pollen and related plant food allergies, the major olive pollen allergen, Ole e 1, as a possible marker for Scrophulariales pollen allergy and the cedar allergens, Cry j 1 and Cry j 2, as potential markers for allergy to Coniferales pollens. We exemplify for Fagales pollen allergy and Bet v 1 that major marker allergens are diagnostic tools to determine the disease-eliciting allergen source. Information obtained by diagnostic testing with marker allergens will be important for the appropriate selection of patients for allergen-specific forms of therapy.

Refolding of the Cupressus arizonica major pollen allergen Cup a1.02 overexpressed in Escherichia coli

The cDNA encoding an isoform of the cypress major pollen allergen, Cup a1.02, has been cloned and expressed in Escherichia coli as a N-terminal 6x His-tagged protein. To increase recovery, Cup a1.02 was expressed at high levels exploiting the T5 strong promoter and led to accumulate as inclusion bodies. The insoluble purified aggregates were solubilized in 6 M guanidine hydrochloride, immobilized using nickel-chelating affinity chromatography, and successfully refolded by controlled removal of the chaotropic reagent. Enhanced protein refolding was observed by reducing the protein concentration at 0.6-0.8 mg/ml. SDS-PAGE and gel filtration chromatography indicated an apparent molecular mass of approximately 40 kDa and the occurrence of the protein as monomers. The reconstituted fusion protein displayed the same immunological properties of the native Cup a1.02 protein as proven by IgE immunoreactivity. Immunoblotting, ELISA, and histamine release test showed that the tag did not preclude the protein functionality hence validating its correct three-dimensional folding. The protein fold was also assessed by CD spectroscopy and deconvolution of the spectrum allowed to estimate the secondary structure as a prevalence of beta structures (higher than 60%) and a small contribution from alpha helices (less than 12%). The reported procedure has proven to be useful for the production of multi-milligrams of recombinant Cup a1.02 allergen suitable for structural biology studies and for the molecular and functional characterization of the IgE binding sites.

IgG binding of mugwort pollen allergens and allergoids exposed to simulated gastrointestinal conditions measured by a self-developed ELISAtest

This study considers the influence of exposure to simulated gastrointestinal conditions (saliva, gut, intestine and acidic conditions of the gut) on IgG binding of unmodified allergens and three types of LMW allergoids of Artemisia vulgaris pollen extract obtained by means of potassium cyanate succinic and maleic anhydride. It also concerns the optimization of a self-developed ELISA assay for comparison of the specific IgG binding of mugwort pollen extract and modified mugwort pollen derivatives. The ELISA was conducted with a mugwort pollen extract coupled to the plate, using the sera from 12 mugwort- pollen allergic patients. The exposure to saliva fluid for 2 min did not influence the IgG binding properties of allergens and allergoids. Exposure of mugwort pollen allergens and LMW allergoids to the acidic conditions of the gut did not dramatically change their IgG binding properties. By exposing mugwort pollen extract and LMW derivatives to the SGF conditions for 1 h, the percent of IgG binding epitopes was reduced to a half of its starting value in the extract and to about 30%in all the allergoid samples. After prolonged exposure only the carbamyl derivative showed reduced IgG binding. Changes of the IgG binding potential of all four samples after exposure in SIF followed a similar pattern.