Identification of a 36-kDa olive-pollen allergen by in vitro and in vivo studies

Hypersensitivity to Pollen of Olea Europea in Patients with Pollen Allergy in Zadar County, Croatia

Preosjetljivost na pelud masline važan je uzrok peludnih alergija u mediteranskim zemljama. Cilj ovoga rada bio je utvrditi učestalost preosjetljivosti na pelud masline među bolesnicima s peludnom alergijom u Zadru i Zadarskoj županiji. Dobivene rezultate usporedili smo s ranijim ispitivanjem preosjetljivosti na pelud masline u Dalmaciji.

Ukupno je obrađen 671 ispitanik s preosjetljivosti na peludne alergene. Od toga broja 61 % ispitanika bilo je muškog spola, a 39 % je bilo ženskog spola. Od ukupno ispitanih 53.5 % činila su djeca u dobi od 4 do 14 godina, a preostalih 46.5 % bili su odrasli u dobi od 15 do 59 godina života. Svim ispitanicima uzeta je detaljna obiteljska i osobna anamneza, napravljen klinički pregled te učinjeno kožno prick-testiranje i enzimatsko-imunološki UniCAP-test za određivanje specifičnih IgE-protutijela. Statistička obrada podataka učinjena je χ2-testom.

Preosjetljivost na pelud masline dokazana je u 8.8 % bolesnika s peludnom alergijom. Najveći broj bolesnika s preosjetljivosti na pelud masline boluje od alergijskog rinitisa, 58 % bolesnika. Postoji statistički značajna razlika u broju bolesnika između dvije ispitivane sredine, gradske i seoske. Samo 3 % bolesnika stanovnici su otoka.

Preosjetljivost na pelud masline u našem ispitivanju najniža je u odnosu na ispitivanja provedena u drugim mediteranskim zemljama. Najčešće se očituje kliničkom slikom alergijskog rinitisa, a statistički je značajno češća u gradskoj sredini. Usporedba preosjetljivosti na pelud masline tijekom dvaju ispitivanih razdoblja u našoj zemlji nije pokazala porast broja bolesnika s preosjetljivosti na pelud masline.

Perinatal risk factors for sensitization, atopic dermatitis and wheezing during the first year of life (PIPO study)

OBJECTIVE

To evaluate the influence of perinatal environmental factors on early sensitization, atopic dermatitis and wheezing during the first year.

METHODS

Information on pregnancy-related factors, parental atopic history, environmental factors and the clinical course of the infant until age one was gathered by questionnaires, as part of a prospective birth cohort study (Prospective study on the Influence of Perinatal factors on the Occurrence of asthma and allergies [PIPO-study]). Quantification of total and specific IgE was performed in 810 children and their parents.

RESULTS

Early sensitization was found in 107/810 (13%) of the infants. Multiple regression analysis showed that specific IgE in fathers was a risk factor for early sensitization in their daughters (adjusted odds ratios (OR(adj)) 2.21 (95% confidence interval (CI) 1.10-4.49); P=0.03), whereas in boys, day care attendance was shown to be protective for early sensitization (OR(adj) 0.38 (95% CI 0.20-0.71); P=0.001). Atopic dermatitis occurred in 195/792 infants (25%). Specific IgE in the mother (OR(adj) 1.52 (95% CI 1.06-2.19); P=0.02) and in the infant (OR(adj) 4.20 (95% CI 2.63-6.68); P<0.001) were both risk factors for the occurence of atopic dermatitis, whereas postnatal exposure to cats was negatively associated with atopic dermatitis (OR(adj) 0.68 (0.47-0.97); P=0.03). Postnatal exposure to cigarette smoke (OR(adj) 3.31 (95% CI 1.79-6.09); P<0.001) and day care attendance (OR(adj) 1.96 (95% CI 1.18-3.23); P=0.009) were significantly associated with early wheezing, which occurred in 25% (197/795) of the infants.

CONCLUSION

The effect of paternal sensitization and day care attendance on sensitization is gender dependent. Maternal sensitization predisposes for atopic dermatitis, whereas postnatal exposure to cats had a protective effect.

Correlation between Olea europaea and Parietaria judaica pollen counts and quantification of their major allergens Ole e 1 and Par j 1-Par j 2

BACKGROUND

In patients with pollinosis, allergic symptoms are often correlated with the number of airborne pollen grains, although this correlation is not always close. The direct measurement of the concentration of aeroallergens has only recently been introduced and is an important advance in public health information systems.

OBJECTIVE

To compare specific quantification of aeroallergens Ole e 1 and Par j 1-Par j 2 Olea and Urticaceae pollen counts.

METHODS

The Hirst method sampler and the Burkard Cyclone sampler were used for pollen count and allergen quantification, respectively. The aerosol was extracted and quantified for Ole e 1 and Par j 1-Par j 2 content using enzyme-linked immunosorbent assay procedures.

RESULTS

Day-to-day variations were observed in both the pollen count and the amount of allergens. Pollen counts and aeroallergen quantification were closely correlated with 99% significance (Olea/Ole e 1: R = 0.892, P < .001; Urticaceae/Par j 1-Par j 2: R = 0.734, P < .001).

CONCLUSION

The technique for the sampling and quantification of aeroallergens presented in this article, based on enzyme-linked immunosorbent assay and applied to the protein extracts directly obtained from the bioaerosol, represents an important advance in the epidemiologic study of allergic respiratory diseases.

The allergenic relevance of profilin (Ole e 2) from Olea europaea pollen

Many works have dealt with the study of the allergenic relevance of profilin from allergenic extracts, mainly derived from pollens and vegetable foods. Olive pollen extracts also contain a profilin allergen (Ole e 2). This protein has been characterized in detail, so the amino-acid sequence of three isoforms and the structural model of one of them are already known. The prevalence of Ole e 2 for olive allergenic patients has been evaluated by different in vivo and in vitro methods, and the results compared with those obtained for another pollen profilins.

Allergenic diversity of the olive pollen

A great number of allergenic proteins have been detected in olive pollen extracts. To date, nine allergens have been isolated and characterized, which have been called Ole e 1 to Ole e 9. The most prevalent olive allergen is Ole e 1, which affects more than 70% of patients hypersensitive to olive pollen, but others, such as Ole e 2, Ole e 8, and Ole e 9, have been demonstrated to be major allergens, and Ole e 6 or Ole e 7 reach high values of clinical incidence. Many of these allergens, such as Ole e 2 (profilin) and Ole e 3 (polcalcin), are involved in cross-reactivities, which agrees with their adscription to panallergenic families. Among the many olive allergens of high molecular mass, only Ole e 9 (46 kDa) has been characterized. The allergen is a polymorphic and glycosylated beta-1,3-glucanase, which belongs to a pathogenesis-related (PR-2) protein family. In addition to the polypeptide epitopes, Ole e 1 also exhibits IgE-binding determinants in the carbohydrate, which are recognized by more than 60% of the sera from patients sensitive to the whole allergen, although the level of such glycan-specific IgE seems not to be clinically relevant in the overall content of the sera. Recent advances in the elucidation of the structure of the Ole e 1-oligosaccharide component allows us to explain the antigenicity of the molecule. Finally, the recombinant production of several allergens from olive pollen in both bacterial and eukaryotic cells has allowed us to resolve problems derived from the polymorphism and scarcity of the natural forms of these allergens. The biological equivalence between the natural and recombinant forms lets us initiate studies on the design of mixtures for clinical purposes, in which hypoallergenic derivatives of these allergens could play a definitive role.

Monoclonal antibody-based method for measuring olive pollen major allergen Ole e 1

BACKGROUND

Olive tree pollen is an important cause of inhalant allergy in Mediterranean countries. The major allergen of this pollen, Ole e 1, has caused reactions in the sera of >80% of olive-sensitive patients. Accurate standardization of allergenic products for diagnosis and immunotherapy is essential to guarantee their quality, and measurement of the major allergen content is becoming an important aspect of standardization procedures.

OBJECTIVE

To develop a two-site enzyme-linked immunoadsorbent assay (ELISA) for the quantification of Ole e 1.

METHODS

BALB/c mice were immunized with purified natural Ole e 1. After fusion and screening by direct ELISA, one of the monoclonal antibodies (5A3) was selected as the capture antibody in an ELISA for Ole e 1 quantification. Bound allergens were detected by a combination of biotinylated Ole e 1-specific polyclonal rabbit antibody and peroxidase-conjugated streptavidin. This ELISA was subsequently evaluated and compared with other techniques.

RESULTS

The developed ELISA was highly reproducible and sensitive, with a detection limit of 0.5 ng/mL and a practical range of 1 to 10 ng/mL. The Ole e 1 content ranged from 3 to 50% of the total protein among the nine Olea europaea pollen extracts studied. The assay also detected Ole e 1-like proteins in pollen from other Oleaceae. Correlation was good between the Ole e 1 content determined by ELISA and scanning densitometry and the immunoglobulin E-binding activity of the extracts.

CONCLUSION

The described Ole e 1 ELISA is sensitive, reproducible, specific, and reliable, and therefore, can be helpful for standardization of olive pollen extracts intended for clinical use.

Privet pollen (Ligustrum sp.) as potential cause of pollinosis in the city of Cordoba, south-west Spain

BACKGROUND

Privet pollen rarely accounts for more than 1% of the annual total of daily pollen concentrations measured in a city; however in areas where these trees are widely used as ornamentals the amounts collected may be high enough to cause allergy symptoms.

METHODS

Air samples taken with volumetric particle samplers Lanzoni VPPS 1000 (Lanzoni s.r.l., Bologna, Italy) show that there are differences in privet pollen concentrations measured in neighbourhoods with a high incidence of privet trees and in those taken at some distance from the source of emission.

RESULTS

The results suggest that differences are due to the short dispersal range of the pollen grains once released from the plant, resulting from both the entomophilous nature of the plant and the large size of the pollen grains. Urban design, moreover, may play an important role in impeding pollen grain dispersion if the air cannot flow freely through long, narrow avenues. Another important consideration is that the last stages of the flowering period of privet overlaps with the flowering period of olive trees, the main allergen in the area. The fact that the two pollen types share common allergens means that there may be a cross-reaction between olive tree pollen and privet pollen.

CONCLUSIONS

Privet pollen should be considered as a potential causative agent of local allergy problems in areas where its presence is extensive and is in combination with other allergens.

The ACVD task force on canine atopic dermatitis (IV): environmental allergens

Numerous environmental allergens have been incriminated in the pathogenesis of canine atopic dermatitis (AD). These include dust and storage mite antigens, house dust, pollens from grasses, trees and weeds, mould spores, epidermal antigens, insect antigens, and miscellaneous antigens such as kapok. In this paper, we review the literature concerning the allergens that have been reported to contribute to canine AD. We conclude that attempts to identify the relevant canine antigens in the past have been plagued by a lack of standardisation of extracts and techniques, and the presence of false-positive and -negative reactions in allergy tests. Until these problems are rectified, it is unlikely that we will be able to provide a list of major and minor antigens for dogs. Hence, we recommend that future studies should be aimed at determining the major patterns of reactivity and cross-reactivity to specific protein allergens within antigenic extracts using electrophoresis and immunoblotting techniques. Once this information becomes available, it may be possible to use a selection of genetically engineered, highly pure antigens for both diagnostic and therapeutic purposes in canine allergy investigations. The use of such antigens will allow standardisation of canine allergy testing and immunotherapy so that the reliability and efficacy of these procedures can be objectively assessed.

Quantification in mass units of group 1 grass allergens by a monoclonal antibody-based sandwich ELISA

BACKGROUND

Grass pollen extracts currently used for allergy diagnosis and immunotherapy are a complex mixture of proteins of which only a few have allergenic activity. Lol p 1 is one of the most important allergens in grass pollen extracts.

OBJECTIVES

To develop a two-site enzyme-linked immunosorbent assay for the quantification of Lol p 1 and other group 1 allergens from grass species, and to assess its suitability for quantifying this group of allergens.

METHODS

Balb/c mice immunized with recombinant Lol p 1 were used for the production of monoclonal antibodies. Screening of hybridomas was performed by direct ELISA, and selected monoclonal antibodies were immobilized on ELISA plates and incubated with samples containing group 1 allergens. Bound allergens were detected by a combination of biotinylated Lol p 1-specific monoclonal antibody and peroxidase-streptavidin conjugate.

RESULTS

The assay is based on three Lol p 1-specific monoclonal antibodies with different epitope specificities. The optimized ELISA measured Lol p 1 concentrations ranging from 125 to 1000 ng/mL and could quantify group 1 allergen from grass species belonging to the Pooidea subfamily. The assay does not depend on anti-sera production or availability of human sera and thus reactives can be produced in unlimited amounts.

CONCLUSION

This sensitive and specific Lol p 1 assay will be helpful both for quantifying the group 1 allergen content of Pooideae pollen extracts intended for clinical use and for studying cross-reactivities among pollen extracts.

Genetic restrictions in olive pollen allergy

BACKGROUND

The major antigen of olive tree pollen, Ole e 1, produces an IgE response restricted by DQ2.

OBJECTIVE

Our purpose was to further analyze the genetic restrictions associated with IgE and IgG antibodies against Ole e 1 and IgE against the recently described antigen Ole e 3.

METHODS

Twenty-two nuclear olive pollen-allergic families (n = 88) were selected. DRB1 and DQB1, TCR-Valpha 8.1, the high-affinity receptor of IgE (FcepsilonRI-beta) Rsa I exon 7 and intron 2 and TNF-beta (LTalpha-Nco I) polymorphisms were determined by PCR and analyzed for association with allergic traits by the multiallelic transmission disequilibrium test.

RESULTS

Significant associations were found among HLA-DQB1*0201 (n = 29) and high levels of IgG (P =.023) and IgE (P =.0136) antibodies to Ole e 1 and with IgE specific to Ole e 3 (P =.0368). DRB1*0701 was associated with high levels of total serum IgE (P =.04) and IgG against Ole e 1 (P =.025). The FcepsilonRI-beta Rsa I exon 7, allele 1 (n = 39), was associated with high levels of total serum IgE (P =. 01), IgE antibodies against Olea europaea extract (P =.004), and specific antibodies to Ole e 1, IgG (P =.04), and IgE (P =.006). The FcepsilonRI-beta Rsa I intron 2, allele 2 (n = 33), was associated with IgE antibodies to O europaea extract (P =.003) and specific antibodies to Ole e 1, IgG (P =.025), and IgE (P =.05).

CONCLUSIONS

We found a new association between IgE antibody response to Ole e 3 and DQB1*0201 and verified the previously reported association between Ole e 1-specific response and DQB1*0201. Also, the association between FcepsilonRI-beta and IgE antibodies against Ole e 1 was demonstrated.

Choosing the right outcomes

Outcome measures are used to monitor the effects of interventions in clinical practice or in formal clinical trials. They may also be used to assess changes within populations either spontaneously or as a result of public-health measures. They are used to monitor the course of illness as part of a management plan or, for larger groups, to identify changes brought about, for instance, by migration or immunization. The choice of outcome measure depends on the age of the child, the complexity of the outcome (for instance, whether its application is to individuals or populations), and the time scale over which it is necessary to detect changes in outcome. The most commonly used outcome measures are clinical symptoms, which are often compiled into scoring systems. Surprisingly, these are often the least well-validated measures of outcome. Physiologic measures, although well validated, are difficult to apply to infants and pre-school children. The role of inflammatory markers is currently limited to research rather than clinical practice. Other outcome measures such as quality of life, impact-of-asthma instruments, and measures to determine the health-economic aspects of asthma are poorly developed in childhood. The right outcome depends on the question being asked, the age of the subjects, and the time scale and complexity over which measurement is required.