Head down tilt 15° in experimental intracerebral hemorrhage: a randomized noninferiority safety trial

BACKGROUND AND PURPOSE

Head down tilt 15° (HDT15°), applied before recanalization, increases collateral flow and improves outcome in experimental ischemic stroke. For its simplicity and low cost, HDT15° holds considerable potential to be developed as an emergency treatment of acute stroke in the prehospital setting, where hemorrhagic stroke is the major mimic of ischemic stroke. In this study, we assessed safety of HDT15° in the acute phase of experimental intracerebral hemorrhage.

METHODS

Intracerebral hemorrhage was produced by stereotaxic injection of collagenase in Wistar rats. A randomized noninferiority trial design was used to assign rats to HDT15° or flat position (n = 64). HDT15° was applied for 1 h during the time window of hematoma expansion. The primary outcome was hematoma volume at 24 h. Secondary outcomes were mass effect, mortality, and functional deficit in the main study and acute changes of intracranial pressure, hematoma growth, and cardiorespiratory parameters in separate sets of randomized animals (n = 32).

RESULTS

HDT15° achieved the specified criteria of noninferiority for hematoma volume at 24 h. Mass effect, mortality, and functional deficit at 24 h showed no difference in the two groups. HDT15° induced a mild increase in intracranial pressure with respect to the pretreatment values (+2.91 ± 1.76 mmHg). HDT15° had a neutral effect on MRI-based analysis of hematoma growth and cardiorespiratory parameters.

CONCLUSIONS

Application of HDT15° in the hyperacute phase of experimental intracerebral hemorrhage does not worsen early outcome. Further research is needed to implement HDT15° as an emergency collateral therapeutic for acute stroke.

Allergen manufacturing and quality aspects for allergen immunotherapy in Europe and the United States: An analysis from the EAACI AIT Guidelines Project

Adequate quality is essential for any medicinal product to be eligible for marketing. Quality includes verification of the identity, content and purity of a medicinal product in combination with a specified production process and its control. Allergen products derived from natural sources require particular considerations to ensure adequate quality. Here, we describe key aspects of the documentation on manufacturing and quality aspects for allergen immunotherapy products in the European Union and the United States. In some key parts, requirements in these areas are harmonized while other fields are regulated separately between both regions. Essential differences are found in the use of Reference Preparations, or the requirement to apply standardized assays for potency determination. As the types of products available are different in specific regions, regulatory guidance for such products may also be available in one specific region only, such as for allergoids in the European Union. Region-specific issues and priorities are a result of this. As allergen products derived from natural sources are inherently variable in their qualitative and quantitative composition, these products present special challenges to balance the variability and ensuring batch-to-batch consistency. Advancements in scientific knowledge on specific allergens and their role in allergic disease will consequentially find representation in future regulatory guidelines.

RItA: The Italian severe/uncontrolled asthma registry

BACKGROUND

The Italian severe/uncontrolled asthma (SUA) web-based registry encompasses demographic, clinical, functional, and inflammatory data; it aims to raise SUA awareness, identifying specific phenotypes and promoting optimal care.

METHODS

Four hundred and ninety three adult patients from 27 Italian centers (recruited in 2011-2014) were analyzed.

RESULTS

Mean age was 53.8 years. SUA patients were more frequently female (60.6%), with allergic asthma (83.1%). About 30% showed late onset of asthma diagnosis/symptoms (>40 years); the mean age for asthma symptoms onset was 30.2 years and for asthma diagnosis 34.4 years. 97.1% used ICS (dose 2000 BDP), 93.6% LABA in association with ICS, 53.3% LTRAs, 64.1% anti-IgE, 10.7% theophylline, and 16.0% oral corticosteroids. Mean FEV₁ % pred of 75.1%, median values of 300/mm³ of blood eosinophil count, 323 kU/L of serum total IgE, and 24 ppb of FENO were shown. Most common comorbidities were allergic rhinitis (62.4%), gastroesophageal reflux (42.1%), sinusitis (37.9%), nasal polyposis (30.2%), and allergic conjunctivitis (30.2%). 55.7% of SUA patients had exacerbations in the last 12 months, 9.7% emergency department visits, and 7.3% hospitalizations. Factors associated with exacerbation risk were obesity (OR, 95% CI 2.46, 1.11-5.41), psychic disorders (2.87, 0.89-9.30-borderline), nasal polyps (1.86, 0.88-3.89-borderline), partial/poor asthma treatment adherence (2.54, 0.97-6.67-borderline), and anti-IgE use in a protective way (0.26, 0.12-0.53). Comparisons to severe asthma multicenter studies and available registries showed data consistency across European and American populations.

CONCLUSIONS

An international effort in the implementation of SUA patients' registries could help to better understand the clinical features and to manage severe asthma, representing a non-negligible socioeconomic burden for health services.

Challenges in the implementation of EAACI guidelines on allergen immunotherapy: A global perspective on the regulation of allergen products

Regulatory approaches for allergen immunotherapy (AIT) products and the availability of high-quality AIT products are inherently linked to each other. While allergen products are available in many countries across the globe, their regulation is very heterogeneous. First, we describe the regulatory systems applicable for AIT products in the European Union (EU) and in the United States (US). For Europe, a depiction of the different types of relevant procedures, as well as the committees involved, is provided and the fundamental role of national agencies of the EU member states in this complex and unique network is highlighted. Furthermore, the regulatory agencies from Australia, Canada, Japan, Russia, and Switzerland provided information on the system implemented in their countries for the regulation of allergen products. While AIT products are commonly classified as biological medicinal products, they are made available by varying types of procedures, most commonly either by obtaining a marketing authorization or by being distributed as named patient products. Exemptions from marketing authorizations in exceptional cases, as well as import of allergen products from other countries, are additional tools applied by countries to ensure availability of needed AIT products. Several challenges for AIT products are apparent from this analysis and will require further consideration.

Immobilization of pH-sensitive CdTe Quantum Dots in a Poly(acrylate) Hydrogel for Microfluidic Applications

Microfluidic devices present the basis of modern life sciences and chemical information processing. To control the flow and to allow optical readout, a reliable sensor material that can be easily utilized for microfluidic systems is in demand. Here, we present a new optical readout system for pH sensing based on pH sensitive, photoluminescent glutathione capped cadmium telluride quantum dots that are covalently immobilized in a poly(acrylate) hydrogel. For an applicable pH sensing the generated hybrid material is integrated in a microfluidic sensor chip setup. The hybrid material not only allows in situ readout, but also possesses valve properties due to the swelling behavior of the poly(acrylate) hydrogel. In this work, the swelling property of the hybrid material is utilized in a microfluidic valve seat, where a valve opening process is demonstrated by a fluid flow change and in situ monitored by photoluminescence quenching. This discrete photoluminescence detection (ON/OFF) of the fluid flow change (OFF/ON) enables upcoming chemical information processing.

Validation of ELISA methods for quantification of the major birch allergen Bet v 1 (BSP090)

To date, the potency of allergen products in Europe is expressed in manufacturer-specific units relative to a product-specific in-house reference. Consequently, cross-product comparability of allergen products from different manufacturers with respect to strength and efficacy is impossible. The Biological Standardisation Programme (BSP) project BSP090 addresses this issue via the establishment of reference standards in conjunction with ELISA methods for the quantification of major allergens in allergen products. Since the initiation of BSP090, the recombinant major allergen Bet v 1 has been adopted by the European Pharmacopoeia Commission as a Chemical Reference Substance (CRS). In parallel, two sandwich ELISA systems for quantification of Bet v 1 were found suitable in preliminary phases of BSP090 to be validated in a large collaborative study. In this study, the candidate ELISA systems were compared with respect to accuracy, precision and variability. Thirteen participating laboratories tested model samples containing the CRS as well as spiked and unspiked birch pollen extracts. Both in pre-testing and in the collaborative study, the 2 candidate ELISA systems confirmed their suitability to quantify recombinant and native Bet v 1. As no clear-cut decision for one of the ELISA systems could be made based on the results of the collaborative study, a post-study testing was performed. Bet v 1 content of 30 birch pollen allergen products was determined in parallel in both ELISA systems. Consequently, 1 candidate ELISA system was selected to be proposed as the future European Pharmacopoeia standard method for Bet v 1 quantification.

Standardization of allergen products: 3. Validation of candidate European Pharmacopoeia standard methods for quantification of major birch allergen Bet v 1

BACKGROUND

The BSP090 project aims at establishing European Pharmacopoeia Reference Substances in combination with the corresponding ELISA methods for the quantification of major allergens in allergen products. Two sandwich ELISAs proved suitable for quantification of Bet v 1, the major birch pollen allergen, in preceding phases of BSP090.

METHODS

Two Bet v 1-specific ELISA systems were compared with respect to accuracy and precision in a ring trial including 13 laboratories. Model samples containing recombinant rBet v 1.0101 as well as native birch pollen extracts were measured independently at least three times in each facility. The assessment was completed with a comparative quantification of Bet v 1 in 30 marketed birch allergen products in one laboratory, simulating the future use as reference method.

RESULTS

In the collaborative study, both candidate ELISAs confirmed their suitability to quantify recombinant and native Bet v 1. ELISA-A showed higher precision and lower interlaboratory variability, yet ELISA-B exhibited slightly higher accuracy. Subsequent parallel measurement of Bet v 1 in a panel of 'real-life' birch allergen products indicated better repeatability of ELISA-B. Both systems detected substantial differences in Bet v 1 content between allergen products, but the effect was more pronounced using ELISA-B due to persistently higher values compared to ELISA-A.

CONCLUSIONS

In the collaborative study, no deciding differences were observed between the two candidate ELISAs. Further comparison under conditions simulating the intended use combined with the criterion of long-term availability enabled the selection of one Bet v 1-specific ELISA for proposal as European Pharmacopoeia standard method.

Characterization and comparison of commercially available mite extracts for in vivo diagnosis

BACKGROUND

Assessment of sensitization by allergen-specific IgE testing and skin prick testing (SPT) are primary tools in routine clinical diagnosis of allergies. To perform a correct diagnosis, it is critical that the allergen reagent used contains an adequate amount of all relevant components. This study aimed at evaluating commercially available mite extracts for in vivo diagnosis from eight manufacturers.

METHODS

Eight extracts from Dermatophagoides pteronyssinus and eight from Dermatophagoides farinae were analysed for total protein content by Bradford and for major allergen content by ELISA. SDS-PAGE, immunoblotting and SPT were also carried out.

RESULTS

The protein amount ranged from 27.7 microg/ml extract to 361.1 microg/ml (D. pteronyssinus) and from 20.3 to 353.0 microg/ml (D. farinae). In regards major allergen concentration, Der p 1 ranged from 9.6 to 36.2 microg/ml, Der f 1 26.5-196.1 microg/ml, mite group 2 0.7-31.7 microg/ml in D. pteronyssinus and 1.3-10.4 microg/ml in D. farinae. SDS-PAGE experiments showed that some components are poorly represented or absent in extracts from most manufacturers. Similar results were obtained by IgE-immunoblotting and SPT with 10 mite allergic patients confirmed a broad spectrum of reactivity of the extracts in the same subject.

CONCLUSIONS

Immunochemical analysis showed a heterogeneous amount of component/s among mite extracts from different manufacturers. These data were confirmed by in vivo testing, suggesting that, for some of the patient tested, the absence of relevant allergens could strongly affect the diagnosis.

The CREATE project: development of certified reference materials for allergenic products and validation of methods for their quantification

Allergen extracts have been used for diagnosis and treatment of allergy for around 100 years. During the second half of 20th century, the notion increasingly gained foothold that accurate standardization of such extracts is of great importance for improvement of their quality. As a consequence, manufacturers have implemented extensive protocols for standardization and quality control. These protocols have overall IgE-binding potencies as their focus. Unfortunately, each company is using their own in-house reference materials and their own unique units to express potencies. This does not facilitate comparison of different products. During the last decades, most major allergens of relevant allergen sources have been identified and it has been established that effective immunotherapy requires certain minimum quantities of these allergens to be present in the administered maintenance dose. Therefore, the idea developed to introduce major allergens measurements into standardization protocols. Such protocols based on mass units of major allergen, quantify the active ingredients of the treatment and will at the same time allow comparison of competitor products. In 2001, an EU funded project, the CREATE project, was started to support introduction of major allergen based standardization. The aim of the project was to evaluate the use of recombinant allergens as reference materials and of ELISA assays for major allergen measurements. This paper gives an overview of the achievements of the CREATE project.

Immunological characterization of a recombinant tropomyosin from a new indoor source, Lepisma saccharina

BACKGROUND

The presence of specific IgE antibodies to invertebrates is common among patients with rhinitis and asthma. Tropomyosin has been described as an invertebrate cross-reactive allergen. We have recently characterized an allergenic extract from silverfish (Lepisma saccharina). Since this insect could be a new source of tropomyosin in the indoor environment, we have thought important to clone and characterize the tropomyosin from it.

METHODS

Recombinant tropomyosin was cloned and characterized by means of immunoblotting with tropomyosin-specific monoclonal antibodies, rabbit polyclonal antibodies and IgE from allergic patients. Its allergenic activity was investigated in histamine release assays. Immunoblotting and ELISA inhibition were carried out to identify the natural tropomyosin in the silverfish extract and to study the cross-reactivity among other arthropod tropomyosins.

RESULTS

Tropomyosin-specific antibodies recognized in immunoblotting the natural tropomyosin in the insoluble fraction of silverfish extract. The silverfish tropomyosin (Lep s 1) was cloned and fully expressed. It shared high homology with other arthropod tropomyosins. rLep s 1 was recognized by tropomyosin-specific monoclonal and polyclonal antibodies and by IgE of allergic patients. It was able to inhibit the IgE binding to the insoluble fraction of silverfish extract, and to induce histamine release by an arthropod-allergic serum. Inhibition experiments revealed IgE cross-reactivity between rLep s 1 and other arthropod tropomyosins.

CONCLUSION

rLep s 1 is the first allergen cloned and characterized from silverfish extract. It enabled us to identify the natural counterpart in the insoluble fraction of silverfish extract, suggesting that the tropomyosin is not readily extractable with a classic aqueous extraction procedure. rLep s 1 displayed biological activity, suggesting that it could be regarded as a useful tool to study the role of silverfish tropomyosin in the sensitization to invertebrate allergic sources.

Localisation of a carbohydrate epitope recognised by human IgE in pollen of Cupressaceae

The objectives of the present study were: (1) to localise, at the subcellular level, the allergens in pollen of Cupressaceae species, using a monoclonal antibody (mAb 5E6) that is specific for carbohydrate epitopes of allergenic components of Cupressus arizonica pollen extract; (2) to determine whether the glycidic epitope recognised by mAb 5E6 was present in pollen of allergenic species taxonomically unrelated to Cupressaceae; and (3) to determine whether human IgE purified from monosensitive patients recognises the same epitope as mAb 5E6 in Cupressaceae pollen. Immunogold labelling of mAb 5E6 showed a high density of gold particles on the orbicules, supporting the hypothesis that they are important vectors of allergens. A high density was also found on the exine and in the cytoplasm, with the latter finding confirming that fragments of pollen ruptured under humid conditions can represent a vector. The glycidic epitope recognised by mAb 5E6 was detected in all of the species taxonomically unrelated to Cupressaceae, although with varying density. Human IgE recognised the same epitope as mAb 5E6. These findings are consistent with observations of diffuse allergenic cross-reactivity among various allergens. The in situ localisation of a common epitope recognised by both a monoclonal antibody and human IgE could be of importance in immunotherapy.

Comparison between the native glycosylated and the recombinant Cup a1 allergen: role of carbohydrates in the histamine release from basophils

BACKGROUND

Cypress pollinosis is an important cause of respiratory allergies. Recently, the Cupressus arizonica major allergen, Cup a1, has been cloned and expressed. The native counterpart of this allergen has been purified and characterized by our group. It has been suggested that sugar moieties play a role in the in vitro IgE binding on Cupressus arizonica pollen extract.

OBJECTIVE

To characterize the immunoreactivity of the recombinant major allergen in comparison with its native counterpart. To evaluate the role of carbohydrate moieties in the IgE-mediated in vitro histamine release from basophils by using the native glycosylated Cup a1 as compared with the recombinant one.

METHODS

Recombinant Cup a1 was expressed in E. coli. IgE reactivity of Cupressaceae-allergic patients on the native as well as the recombinant molecule was investigated by immunoblotting, ELISA experiments and histamine release test from passively sensitized basophils.

RESULTS

Fourteen out of 17 Cup a1-positive sera had IgE antibodies reactive with the native molecule only and lost their reactivity-after periodate deglycosylation of the allergen. Moreover, only native molecule was capable of inducing histamine release by this group of sera. Both the recombinant and the native molecules were recognized by three out of the 17 sera and were equally capable of triggering degranulation.

CONCLUSION

A large number of sera reactive with the major allergen recognize carbohydrate epitopes only. IgE from these sera are able to induce histamine release from basophils and they might play a functional role in the clinical symptoms of allergy.

Preparation and characterization of silverfish (Lepisma saccharina) extract and identification of allergenic components

BACKGROUND

Airborne insect antigens represent important aeroallergens which have been widely investigated. Although it has been demonstrated that house dust contains significant silverfish (Lepisma saccharina) levels, none of the extracts obtained so far has been extensively characterized. Thus, we have prepared and characterized a silverfish extract and investigated its IgE-reactive components by testing the reactivity of sera from patients allergic to inhalant insect allergens.

METHODS

The extract from silverfish insect bodies was prepared by homogenizing frozen silverfish in Tris-HCl buffer. The soluble material (Sup) was filtered and the insoluble material (Ppt) was resuspended in 100 mM Tris pH 10.6. The two fractions were characterized by biochemical and immunochemical methods. IgE reactivity was investigated on both fractions before and after periodate treatment.

RESULTS

Protein content and total carbohydrates was 2 and 3% w/w for Sup and 1 and 0.3% w/w for Ppt. The SDS-PAGE profile of the two fractions showed a different pattern in the MW range of 5-175 kD. Sup and Ppt, probed with allergic sera, showed a complex pattern of IgE reactivity. When periodate-treated fractions were tested, IgE reactivity was either completely abrogated, reduced or not affected, depending on the allergic serum employed.

CONCLUSIONS

The results obtained indicate that the classic aqueous-extraction procedures that have been used up to now for other insects might not be completely satisfactory, since several allergenic components are not soluble at the normally used pH. We developed a dedicated extraction procedure allowing the detection of a certain degree of reactivity in sera negative to allergens extracted following classic procedures.

Rapid isolation, characterization, and glycan analysis of Cup a 1, the major allergen of Arizona cypress (Cupressus arizonica) pollen

BACKGROUND

A rapid method for the purification of the major 43-kDa allergen of Cupressus arizonica pollen, Cup a 1, was developed.

METHODS

The salient feature was a wash of the pollen in acidic buffer, followed by an extraction of the proteins and their purification by chromatography. Immunoblotting, ELISA, and lectin binding were tested on both the crude extract and the purified Cup a 1. Biochemical analyses were performed to assess the Cup a 1 isoelectric point, its partial amino-acid sequence, and its glycan composition.

RESULTS

Immunochemical analysis of Cup a 1 confirmed that the allergenic reactivity is maintained after the purification process. Partial amino-acid sequencing indicated a high degree of homology between Cup a 1 and allergenic proteins from the Cupressaceae and Taxodiaceae families displaying a similar molecular mass. The purified protein shows one band with an isoelectric point of 5.2. Nineteen out of 33 sera (57%) from patients allergic to cypress demonstrated significant reactivity to purified Cup a 1. MALDI-TOF mass spectrometry indicated the presence of three N-linked oligosaccharide structures: GnGnXF(3) (i.e., a horseradish peroxidase-type oligosaccharide substituted with two nonreducing N-acetylglucosamine residues), GGnXF(3)/GnGXF(3) (i.e., GnGnXF with one nonreducing galactose residue), and (GF)GnXF(3)/Gn(GF)XF(3) (with a Lewisa epitope on one arm) in the molar ratio 67:8:23.

CONCLUSION

The rapid purification process of Cup a 1 allowed some fine studies on its properties and structure, as well as the evaluation of its IgE reactivity in native conditions. The similarities of amino-acid sequences and some complex glycan stuctures could explain the high degree of cross-reactivity among the Cupressaceae and Taxodiaceae families.

Cupressaceae pollinosis: identification, purification and cloning of relevant allergens

Allergy to Cupressaceae pollen is a worldwide pollinosis caused by several species. Pollen extracts prepared from allergenic species belonging to this family are characterised by low protein and high carbohydrate content. The allergenic components represented in the pollen extracts from different species of the Cupressaceae family show high levels of cross-reactivity when probed with human IgE from allergic subjects and share a number of common epitopes also identified by polyclonal rabbit antisera and monoclonal antibodies. A close relationship has also been described with the Taxodiaceae and Podocarpaceae families. Although both proteic and carbohydrate epitopes appear to be involved in IgE recognition and allergenic cross-reactivity, a large portion of the IgE reactivity of Cupressaceae-allergic patients seems to be associated with sugar moieties present on the relevant allergenic molecules. From this point of view, Cupressaceae/Taxodiaceae allergens constitute a particularly useful model to study IgE cross-reactivity, as they have been shown to display different levels of homology. Moreover, the availability of the purified allergens, together with their recombinant counterparts, may shed light on the actual role played by carbohydrate in allergic sensitisation, IgE recognition and allergenic cross-reactivity.

A monoclonal antibody specific for a carbohydrate epitope recognizes an IgE-binding determinant shared by taxonomically unrelated allergenic pollens

Carbohydrate epitopes are capable of binding human IgE from allergic subjects and these epitopes play a role in the cross-reactivity between allergens from unrelated sources. A monoclonal antibody (5E6), specific for a carbohydrate epitope detectable on components of Cupressus arizonica pollen extract, has been produced and characterized. To study the relationship between the epitopes recognized by the monoclonal antibody and by IgE from allergic subjects. To investigate the presence of such carbohydrate IgE determinant in extracts from 21 pollen species belonging to 16 taxonomically related and unrelated families, by means of the monoclonal antibody. IgG-depleted fraction from protein G-purified human allergic serum was obtained. The monoclonal antibody and the IgE from the purified fraction were tested on two glycoproteins, polyamine oxidase and ascorbate oxidase, adsorbed on the ELISA plates. The relationship between the monoclonal- and the IgE-recognized epitopes was investigated by ELISA-competition experiments. Analysis of the distribution of this carbohydrate epitope was performed by direct binding of the monoclonal antibody onto the various extracts. The monoclonal antibody and the IgE were able to bind carbohydrate epitopes on the two plant glycoproteins, ascorbate oxidase and polyamine oxidase. Polyamine oxidase shows only one N-glycosilation site whose carbohydrate moiety seems to be composed of a branched chain of seven ordered sugars, i.e. two N-acetyl-D-glucosamine-, three mannose-, one fucose- and one xylose-residues. This structure bears the epitope recognized by mAb 5E6. Human IgE from the IgG-depleted fraction were found capable of inhibiting the monoclonal antibody binding. The allergenic epitope identified was shared by a large number of extracts with different levels of reactivity (OD490 ranging from 0.110 to 2.060). Our data support the finding that a monoclonal antibody specific for a carbohydrate epitope of Cupressus arizonica pollen extract detects an epitope which is also recognized by IgE from allergic subjects. This characterized reagent could be a useful tool for studying distribution of cross-reactive carbohydrate determinants in allergenic pollen extracts and their components.

Allergenicity of mare's milk in children with cow's milk allergy

BACKGROUND

Cow's milk allergy is a common disease of infancy and early childhood. If the baby is not breast-fed, a substitute for cow's milk formula is necessary.

OBJECTIVE

The aim of this study was to investigate, in vitro and in vivo, the allergenicity of mare's milk in a population of selected children with severe IgE-mediated cow's milk allergy.

METHODS

Twenty-five children (17 male and 8 female) aged 19 to 72 months (median age 34 months) with IgE-mediated cow's milk allergy were selected for this study. All the children underwent skin prick tests with cow's milk and mare's milk and double-blind placebo-controlled oral food challenge (DBPCOFC) with fresh cow's milk, fresh mare's milk, and, as placebo, a soy formula (Isomil, Abbott, Campoverde, Italy). We performed immunoblotting of cow's and mare's milk developed with IgE from allergic children.

RESULTS

All the children showed strong positive skin test responses to cow's milk (4+); 2 children had positive skin test responses to mare's milk (2+). All children had positive DBPCOFCs to cow's milk; one child had a positive DBPCOFC to mare's milk. No children reacted to the placebo (Isomil). In the cow's milk, some proteins are able to strongly react with human IgE; when the sera are tested with mare's milk, the bands corresponding to the same proteins are recognized by a lower percentage of sera.

CONCLUSION

These data suggest that mare's milk can be regarded as a good substitute of cow's milk in most children with severe IgE-mediated cow's milk allergy. It would be prudent, however, to confirm its tolerability by a supervised titrated oral challenge test.

Role of carbohydrate moieties in IgE binding to allergenic components of Cupressus arizonica pollen extract

BACKGROUND

A reduction of IgE immunoreactivity after periodate-treatment has been previously reported for various glycoprotein allergens.

OBJECTIVE

The aim of this study was to investigate the role of glycan moiety of a C. arizonica extract in the binding of patients' IgE and to identify the carbohydrates possibly involved.

METHODS

The reactivity of IgE with C. arizonica extract, before and after periodate-treatment, was evaluated by immunoblotting and ELISA inhibition. The specificity of carbohydrate-reactive IgE was evaluated by ELISA using unrelated glycoproteins with known sugar composition and structure, such as pineapple bromelain, honeybee venom phospholipase A2, and ovalbumin, before and after periodate treatment.

RESULTS

When periodate-treated C. arizonica extract was probed after SDS-PAGE and immunoblotting with patients' IgE, no reactivity could be detected. Furthermore, a very poor inhibitory activity of the periodate-treated C. arizonica extract as compared with the untreated sample could be observed in the ELISA inhibition experiments performed using C. arizonica extract as antigen. When phospholipase A2 and bromelain were used as antigens in ELISA, they were recognized by patients' IgE, whereas ovalbumin was negative. Treatment of phospholipase A2 and bromelain with periodate completely abolishes the IgE reactivity.

CONCLUSION

A large portion of the IgE reactivity of Cupressaceae-allergic subjects appears to be associated with sugar moieties of C. arizonica extract which appear to be shared by bromelain and phospholipase A2, thus suggesting that the IgE of patients reacting with such epitopes probably react with beta 1 --> 2 xylose, alpha 1 --> 3 fucose and/or alpha 1 --> 6 fucose.

Specific IgE to cross-reactive carbohydrate determinants strongly affect the in vitro diagnosis of allergic diseases

BACKGROUND

Cross-reacting carbohydrate determinants (CCDs) are antigenic structures shared by allergenic components from taxonomically distant sources. The case history of a patient with a great discrepancy between skin test and specific IgE results led us to investigate the role of these determinants in his specific case and in an allergic population.

OBJECTIVE

We sought to determine the role of CCDs in causing false-positive and clinically irrelevant results in in vitro tests.

METHODS

The involvement of CCDs was studied by specific IgE inhibition by using glycoproteins with a known carbohydrate structure. Direct and inhibition assays were performed by commercially available systems, in-house ELISA, and the immunoblotting technique. The binding to the periodate-oxidated carbohydrate structure of glycoproteins and allergenic extracts was also evaluated. A comparative study between skin test and specific IgE responses to the antigens studied was carried out in 428 consecutive allergic subjects.

RESULTS

All the tests performed suggested that cross-reacting carbohydrate epitopes were the cause of false-positive specific IgE results in one of the commercial systems and the high reactivity in all the solid-phase in vitro tests. None of the cross-reacting carbohydrate allergens yielded a positive skin test response. Periodate treatment caused variable degrees of reduction of IgE binding to the different antigens studied, indicating that CCDs played a different role in each of them. About 41% of patients allergic to pollen had specific IgE for a glycoprotein, without a positive skin test response to the same molecule.

CONCLUSIONS

CCDs must be taken into account when evaluating the clinical relevance of positive results in in vitro specific IgE assays, at least in the diagnosis of patients with pollen allergy. Commercial systems should be carefully assessed for the ability to detect specific IgE for carbohydrate determinants to avoid false-positive or clinically irrelevant results.

Interleukin-12 induces expression of interferon regulatory factor-1 via signal transducer and activator of transcription-4 in human T helper type 1 cells

IRF-1-deficient mice show a striking defect in the development of T helper 1 (Th1) cells. In the present report, we investigate the expression of IRF-1 during differentiation of human T helper cells. No significant differences of IRF-1 mRNA expression were found in established Th1 and Th2 cells; however, interleukin 12 (IL-12) induced a strong up-regulation of IRF-1 transcripts in Th1 but not in Th2 cells. We demonstrate that IL-12-induced up-regulation of IRF-1 is mediated by signal transducer and activator of transcription-4, which binds to the interferon (IFN)-gamma-activated sequence present in the promoter of the IRF-1 gene. Strong IL-12-dependent activation of a reporter gene construct containing the IRF-1 IFN-gamma-activated sequence element provides further evidence for the key role of signal transducer and activator of transcription-4 in the IL-12-induced up-regulation of IRF-1 transcripts in T cells. IRF-1 expression was strongly induced after stimulation of naive CD4(+) T cells via the T cell receptor, irrespective of the cytokines present at priming, indicating that this transcription factor does not play a major role in initiating a Th1-specific transcriptional cascade in differentiating helper T cells. However, our finding that IRF-1 is a target gene of IL-12 suggests that some of the IL-12-induced effector functions of Th1 cells may be mediated by IRF-1.

Serum anti-beta2-glycoprotein I antibodies from patients with antiphospholipid antibody syndrome bind central nervous system cells

Sera from 20 patients with antiphospholipid syndrome (APS), primary or secondary to systemic lupus erythematosus (SLE), or with SLE, were assayed by immunoblot analysis for anti-beta2-glycoprotein I antibodies (abeta2-GPI), and by indirect immunofluorescence (IIF) technique for reactivity with astrocyte and neuron cell lines and with histological sections of human brain biopsies and monkey cerebellum. Six sera from healthy donors were studied as a control. Eleven out of the 20 patient sera contained abeta2-GPI and were immunoreactive with astrocytes and neurons, both in culture and in the histological sections, and with the endotheliocytes of the microvessels present in the histological sections. Cell localization and the pattern of immune reaction were similar to those obtained with a monoclonal antibody abeta2-GPI. Eight of the remaining patient sera, found abeta2-GPI-, did not react with the nervous substrates (and the control sera), while one exhibited immunoreactivity analogous to the abeta2-GPI+ sera. The interference of anticardiolipin antibodies (aCL) in the immunoreactivity with the nervous substrates was excluded since aCL were present in all patient sera and no immune reaction was observed in the histological sections incubated with a monoclonal aCL. Therefore, the binding of abeta2-GPI from patients to cells of the central nervous system (CNS) occurs independently from aCL. This issue may be relevant to further evaluate the potential pathogenetic role of abeta2-GPI in the CNS damage of APS-like conditions.

Juniperus oxycedrus: a new allergenic pollen from the Cupressaceae family

BACKGROUND

Cupressaceae allergy is a worldwide pollinosis caused by several species. Some species in limited geographic areas pollinate in fall and winter. Juniperus oxycedrus matches these features.

OBJECTIVE

We sought to define the immunochemical, allergologic, and environmental aspects of J. oxycedrus pollen.

METHODS

Pollen extract from J. oxycedrus was prepared and characterized by biochemical analysis and human specific IgE binding by means of ELISA and immunoblotting. A 3-year phenological study was conducted to define the pollinating period of J. oxycedrus. Forty consecutive patients allergic to cypress were recruited in two areas and divided into two groups according to their exposure to J. oxycedrus pollen. Clinical evaluation, skin prick tests, and specific IgE determination with J. oxycedrus, J. ashei, and Cupressus arizonica extracts were carried out on both groups.

RESULTS

J. oxycedrus pollen extract was obtained, and it showed specific IgE binding and wide cross-reactivity with other Cupressaceae species. The extract caused a positive skin test response in all the patients tested, with about 80% of them having detectable specific IgE. Symptoms related to J. oxycedrus pollen exposure were recorded in 72% of the directly exposed patients and occasionally in 9% of the nonexposed patients. In the Mediterranean coastal area considered, J. oxycedrus was the first Cupressaceae species that started to pollinate at the beginning of November and ended in the first part of December.

CONCLUSIONS

J. oxycedrus represents a newly characterized pollen species of the Cupressaceae family that cross-reacts with other members of the same family. Subjects with cypress allergy have in vivo and in vitro positive test responses for J. oxycedrus and can show symptoms when exposed to its pollen. Finally, the most important feature of J. oxycedrus is its early pollinating period in southern Europe (Italy), causing a further extension of the cypress pollen season in areas where other Cupressaceae species are present.

Molecular characterization of a cross-reactive Juniperus oxycedrus pollen allergen, Jun o 2: a novel calcium-binding allergen

BACKGROUND

Species belonging to the Cupressaceae family are a relevant source of allergens that are present in a wide number of countries.

OBJECTIVE

We sought to identify, purify, and characterize recombinant allergens from Juniperus oxycedrus, a species belonging to the Cupressaceae family.

METHODS

Double-stranded cDNA was synthesized from mRNA and cloned into the lambda-ZAP expression vector. IgE screening of the library was performed with a pool of sera from subjects allergic to Cupressaceae. A recombinant 6xHis-tagged Juniperus oxycedrus allergen, Jun o 2, was expressed in Escherichia coli and purified by Ni2+ affinity chromatography. It was studied further by immunoblotting inhibition with pollen extracts from other Cupressaceae, Oleaceae, Urticaceae, and Graminaceae. The role of protein-bound calcium on the allergen's IgE-binding capacity was tested in a plaque assay in the presence or absence of EGTA.

RESULTS

A cDNA coding for a newly identified Juniperus oxycedrus pollen allergen, rJun o 2, was isolated. The deduced amino acid sequence contained four typical Ca2+ binding sites and showed a significant sequence similarity to calmodulins. Depletion of Ca2+ in the plaque assay led to a loss of IgE-binding capacity of rJun o 2. Immunoblotting inhibition revealed that J. oxycedrus, J. ashei, Cupressus arizonica, C. sempervirens, Parietaria judaica, Olea europaea, and Lolium perenne pollen extracts were able to inhibit IgE binding to blotted rJun o 2 at different concentrations.

CONCLUSION

rJun o 2 contains IgE-binding epitopes shared by taxonomically unrelated species, and therefore it can be regarded as a new panallergen. These findings could contribute to an explanation for the phenomenon of multiple positive test results in polysensitized patients and the potential symptom-eliciting role of allergenic sources previously not encountered.

Arizona cypress (Cupressus arizonica) pollen allergens. Identification of cross-reactive periodate-resistant and -sensitive epitopes with monoclonal antibodies

Species of the Cupressaceae family are a worldwide cause of respiratory allergies. We used monoclonal antibodies (mAbs) to investigate the presence and the nature of cross-reacting epitopes shared by various components within Cupressus arizonica pollen extract (CaE) or by CaE and pollen extract from C. sempervirens (CsE). mAbs were produced in mice immunized with whole CaE (4A6 and 5E6) or with the major allergen components (2D5). Their reactivity was investigated by ELISA and immunoblotting before and after CaE periodate treatment. Cross-reactivity was evaluated by ELISA inhibition and immunoblotting. mAbs 2D5 and 4A6 recognized periodate-resistant epitopes, whereas the mAb 5E6 reacted with a periodate-sensitive determinant. The former mAbs recognized epitopes present on CaE major allergen and also shared by other components. mAb 5E6 showed a spread reactivity on CaE, with exclusion of the major allergen. When the three mAbs were tested with CsE, a restricted pattern of reactivity to mAbs 2D5 and 4A6 was obtained, whereas mAb 5E6 maintained a spread reactivity. The CaE major allergen is represented by two components recognized by human IgE and sharing common epitopes, as proven by mAbs reactivity. The use of these mAbs demonstrates that cross-reactivity within CaE components and between CaE and CsE is due to the presence of periodate-sensitive as well as -resistant epitopes.

Major histocompatibility complex-independent recognition of a distinctive pollen antigen, most likely a carbohydrate, by human CD8+ alpha/beta T cells

We have isolated CD8+ alpha/beta T cells from the blood of atopic and healthy individuals which recognize a nonpeptide antigen present in an allergenic extract from Parietaria judaica pollen. This antigen appears to be a carbohydrate because it is resistant to proteinase K and alkaline digestion, is hydrophilic, and is sensitive to trifluoromethane-sulphonic and periodic acids. In addition, on a reverse-phase high performance liquid chromatography column the antigen recognized by CD8(+) T cells separates in a fraction which contains >80% hexoses (glucose and galactose) and undetectable amounts of proteins. Presentation of this putative carbohydrate antigen (PjCHOAg) to CD8+ T cell clones is dependent on live antigen presenting cells (APCs) pulsed for >1 h at 37 degrees C, suggesting that the antigen has to be internalized and possibly processed. Indeed, fixed APCs or APCs pulsed at 15 degrees C were both unable to induce T cell response. Remarkably, PjCHOAg presentation is independent of the expression of classical major histocompatibility complex (MHC) molecules or CD1. CD8+ T cells stimulated by PjCHOAg-pulsed APCs undergo a sustained [Ca2+]i increase and downregulate their T cell antigen receptors (TCRs) in an antigen dose- and time-dependent fashion, similar to T cells stimulated by conventional ligands. Analysis of TCR Vbeta transcripts shows that six independent PjCHOAg-specific T cell clones carry the Vbeta8 segment with a conserved motif in the CDR3 region, indicating a structural requirement for recognition of this antigen. Finally, after activation, the CD8+ clones from the atopic patient express CD40L and produce high levels of interleukins 4 and 5, suggesting that the clones may have undergone a Th2-like polarization in vivo. These results reveal a new class of antigens which triggers T cells in an MHC-independent way, and these antigens appear to be carbohydrates. We suggest that this type of antigen may play a role in the immune response in vivo.

[Comparison of preschool children's performance using the Denver developmental test, before and after nutritional intervention]

Psychomotor and development analysis must be emphasized when studying institutionalized children. Many previous investigations have been showing deleterious effects of day care centers over developmental performance in children.

OBJECTIVE

This study is aimed at comparing the performance in the Development Screening Test (Denver) in children attending day care centers, before and after nutritional intervention with an energetic supplement enriched with iron.

METHOD

130 children from 2 to 6 years old, attending three municipal day care centers, were evaluated by means of the application of the Denver test; by trained psychologists, comparing the collected data according to sex and age group, before and after six months intervention with iron enriched protein energetic supplement.

RESULTS

Most of the children had normal performance, both in first application (70.80%), and in the second one (80.80%). When comparing these results, 76.92% of the children had not altered their performance and 18.46% improved it substantially. As to sex, no significant differences were found and as to age group, there was significant improvement among children aged 4 to 6 years of age.

CONCLUSIONS

Besides the nutritional aspects, factors such as learning readiness, family organization, and psychopedagogic orientation to the day care centers, must have fostered development, even if the low socioeconomic level of the studied population is considered.

Cross-reactivity between Cupressus arizonica and Cupressus sempervirens pollen extracts

BACKGROUND

Cupressus arizonica and C. sempervirens, two species belonging to the Cupressaceae family, are recognized as an important cause of respiratory allergies in countries with a Mediterranean climate.

OBJECTIVE

The relationship between pollen extracts from these two species was studied by evaluating the reactivity with polyclonal rabbit antisera and human IgE.

METHODS

The two extracts were analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis. Cross-reactivity was evaluated by ELISA and immunoblotting inhibition experiments.

RESULTS

The electrophoretic patterns of the two extracts are quite different, although some components display identical molecular weights. The immunoblotting developed with human IgE from subjects allergic to members of the Cupressaceae family indicated that two major IgE-reactive components, displaying molecular weights of about 43,000 and 36,000 d, were similarly detected in both extracts. Inhibition experiments showed a high degree of crossreactivity between the two extracts when tested with rabbit polyclonal antibodies against C. arizonica and C. sempervirens. When tested with human IgE inhibition methods, both extracts were able to reciprocally inhibit all of the IgE-reactive bands, although C. arizonica extract was always a better inhibitor.

CONCLUSIONS

C. arizonica and C. sempervirens extracts are highly cross-reactive at the IgE level and share a number of common epitopes also identified by polyclonal rabbit antisera.

Assessment of skin prick test and serum specific IgE detection in the diagnosis of Cupressaceae pollinosis

BACKGROUND

There is increasing evidence for the relevance of Cupressaceae pollinosis among persons living in geographic areas where these species are native or imported.

OBJECTIVE

Previously reported problems in obtaining valid allergenic extracts to be used in the diagnosis of this winter pollinosis prompted us to assess the value of available Cupressaceae pollen extracts for in vivo and in vitro diagnosis.

METHODS

Commercial and in-house allergenic extracts from Cupressaceae and Taxodiaceae families were used for skin prick testing and specific IgE detection in six groups of subjects exposed to a high concentration of Cupressaceae pollen.

RESULTS

Four commercial and two in-house Cupressus sempervirens pollen extracts showed low cutaneous reactivity. Positive test results were recorded in 26% of the 713 subjects tested. C. arizonica in-house pollen extracts gave rise to larger cutaneous reactions. Furthermore, the skin prick test response was positive in a greater number of subjects (38%) of the same group. Six commercial immunoassays were able to detect specific IgE to C. sempervirens in rates ranging from 8.1% to 81.1%. Specific IgE to C. arizonica was detected by means of an in-house immunoenzymatic method in 70.3% of 54 patients with suspected "cypress" allergy, and specific IgE to C. sempervirens was detected in 75.9% of these patients by using a commercial system. High rates of cross-reactivity within the Cupressaceae family and with species of the Taxodiaceae family were recorded with both in vivo and in vitro tests.

CONCLUSIONS

The use fo C. sempervirens in vivo diagnostics should be carefully evaluated until better characterized extracts are developed. In-house-characterized extracts of C. arizonica seem to be more reliable in the diagnosis of Cupressaceae allergy by means of skin prick testing. the sensitivity of commercially available in vitro methods to detect specific IgE to C. sempervirens should be carefully evaluated; nevertheless, valid results can be obtained with some already available immunoassays.

Detection of phosphatidylcholine-specific phospholipase C in NIH-3T3 fibroblasts and their H-ras transformants: NMR and immunochemical studies

Although evidence supports constitutive activation of phosphatidylcholine specific phospholipase C (PC-plc) in rastransformed fibroblasts, no studies have been devoted to measure the basal activity levels of this enzyme, its molecular characteristics and subcellular localization. This paper reports for the first time measurements of the activity of different enzymes responsible for PC hydrolysis (PC-plc; phospholipases A2 (pla2) and A1 (pla1)) in homogenates of murine NIH-3T3 fibroblasts (3T3) and their transformants obtained by human H-ras transfection (3T3ras). To this end, 31P NMR analyses were carried out on total cell homogenates, incubated in the presence of mixed diheptanoylphosphatidylcholine: sphingomyelin (DHPC:SM) unilamellar vesicles (SLUV), in which DHPC acts as a suitable substrate for water-soluble lipolytic enzymes. The basal PC-plc activity levels (0.66 +/- 0.14 and 0.38 +/- 0.10 nmol/10(6) cells.hour in 3T3 and 3T3ras fibroblasts, respectively),were substantially higher (over 30-50x) than those reported in the literature for normal mammalian cells (dog heart myocytes). Moreover the PC-plc activity was about 15-30 times lower than the overall PC deacylation activity in both clones. The use of high titer polyclonal antibodies, raised in a rabbit against bacterial PC-plc, allowed identification of one cross-reactive mammalian PC-plc component (M(r) 66 kD) in cell lysates of both 3T3 and 3T3ras fibroblasts, and detection, by indirect immunofluorescence, of its subcellular localization. In control 3T3 fibroblasts (in the late log-phase of growth) the enzyme was exclusively located in the cytosol, while in H-ras transformed cells it was massively exposed on the external side of the membrane. This new finding strongly suggests that the oncogenic product p2Iras is able to induce (or mediate) translocation of PC-plc across the plasma membrane of ras transformed cells, with possible implications not only on cell biochemistry (enhancement of PC-plc activity, and consequent production of intra- and extracellular PCho and accumulation of neutral lipids) but also on cell-cell interaction mechanisms which facilitate tumour invasion and metastasis of oncogene-transformed cells.

Parietaria judaica-specific T-cell clones from atopic patients: heterogeneity in restriction, V beta usage, and cytokine profile

The pollen of Parietaria spp. is one of the most clinically relevant sources of allergens in the Mediterranean area. CD4+ T-lymphocyte clones specific for Parietaria allergens were isolated from peripheral blood of atopic donors, and their phenotype, HLA restriction, V beta usage, and cytokine profile were determined. All the T-cell clones expressed the alpha/beta T-cell receptor and were induced to express CD40 ligand after activation with phorbol-myristate-acetate plus ionomycin. When the proliferative response to three chromatographic fractions of the extract was analyzed, distinct reactivity patterns were found. Interestingly, most of the clones responded to the fraction that was the most enriched for the major allergen Par j 1. The clones were either HLA-DR- or HLA-DQ-restricted and did not show any preferential usage of T-cell receptor V beta segments. Five of the 17 clones tested produced only IL-4 and no interferon-gamma, thus displaying a TH2 phenotype. The other clones displayed a TH0 phenotype in that they produced both IL-4 and interferon-gamma. These results show that in atopic patients T-cell response against Parietaria judaica allergen involves different T-cell subsets in terms of restriction, V beta usage, and cytokine profile.

Use of monoclonal antibodies in the standardization of Parietaria judaica allergenic extracts

Two monoclonal antibodies (MoAb) specific for Parietaria judaica allergenic components were selected on the basis of their capability to recognize either the Parietaria judaica major allergen (MoAb 1A6/1D1) or several other allergenic components (MoAb 1A4/2F8) except the major allergen. These two antibodies, either individually or combined, were used to develop an ELISA-inhibition system using a reference Parietaria judaica extract (in-house Reference preparation, IHR). The assays performed with these reagents were firstly standardized by testing the IHR several times. A good reproducibility, evaluated both at the level of 50% inhibition values, and in terms of analysis of the variance of the slopes of the regression curves, was obtained. Subsequently, the potency of several Parietaria judaica extracts, either obtained by manufacturing companies or produced in other laboratories, was evaluated by these tests. Data obtained by interpolation with the IHR values and expressed in terms of arbitrary units (AU) were compared with those obtained by classical human IgE inhibition, performed with sera from allergic patients. Results indicate that the monoclonal antibodies produced in our laboratory can be successfully employed, either individually or combined, in the standardization of allergenic preparations in addition to, and possibly replacing, the classical IgE-based standardization procedures which require human specimens often available in limited amounts only.

IgG subclass antibodies against Parietaria judaica in normal and allergic subjects

IgG antibody response to the inhalant allergen Parietaria judaica (Pj) and IgG subclass distribution were studied in 82 normal subjects, divided into three groups according to age (0-1, 1-20, and 20-60 years) and in 32 allergic subjects aged 20-60 years. Both normal and allergic subjects showed an IgG response, and all had IgG1 antibodies specific for PjE. Serum IgG2, IgG3, and IgG4 against PjE were detectable in 36%, 46%, and 22% of normal subjects, and in 58%, 31%, and 65% of allergic subjects, respectively. A significant difference in class distribution between allergic and age-matched normal subjects was found only for IgG4 antibodies against PjE (65% and 17%; P < 0.01). The ELISA results were also analyzed quantitatively, taking into account the relative proportion of specific antibodies. Thus, in normal subjects IgG1 antibodies showed a decreasing trend as the age rose, while no differences according to the age of the subject were found for IgG2 and IgG4. When data from allergic subjects (20-60 years) and the age-matched normal group were compared, they were different for the relative percentage of IgG2 only, showing for this a significantly lower value (P < 0.001). The present data indicate that normal and allergic subjects show differences in the IgG isotype distribution depending on their sensitivity and duration of allergen exposure.

Purification and fine characterization of a major allergen from Olea europaea pollen extract

Olea europaea (olive) pollen extract was prepared by aqueous extraction and characterized by biochemical and immunochemical methods. Two components, displaying respective mol. wt. of 17,000 and 19,000, were the most reactive allergens, being the doublet (designated Ole e I) recognized by most sera tested. The 19,000 mol. wt. component, purified by conventional biochemical procedure and lectin-affinity chromatography from the Ole e I doublet, was deglycosylated and analyzed by SDS-PAGE and by ELISA inhibition. The results obtained suggest that the 19,000 mol. wt. component represents the glycosylated form of the 17,000 component.

CD23/Fc epsilon RII expression on phytohemagglutinin-A- or phorbol-12myristate-13acetate-Ca(2+)-activated human tonsil T cells

The low-affinity Fc receptor for IgE, CD23/Fc epsilon RII, has been expressed in T cell lines and pathologic T cells, but its presence on normal human T cells is still debated. We studied the expression of CD23/Fc epsilon RII on purified T cells from normal peripheral blood mononuclear cells (PBMC) or tonsil T cells stimulated with 10 micrograms/ml phytohemagglutinin A (PHA) or phorbol-12myristate- 13acetate (PMA) Ca2+. Using two-dimensional flow cytometry, the tonsil T-cell-enriched population showed > 10% of CD23/Fc epsilon RII expression when coexpressed with the CD3 antigen. CD4+ T cells appear to be principally involved in the expression of CD23/Fc epsilon RII, although we were unable to detect a clear expression of CD23/Fc epsilon RII in PBMC that were activated with either PHA or PMA Ca2+. PHA stimulation resulted in the release of IgE binding factor (IgEBF). The induction of CD23/Fc epsilon RII expression in PHA- and PMA-Ca(2+)-activated T cells was enhanced by IL-4, but not by IgE or IL-6. IL-4 also augmented the PHA- and PMA-Ca(2+)-induced release of IgEBF. The addition of supernatant from the Epstein-Barr virus (EBV)-infected cell line to PHA- or PMA-Ca(2+)-stimulated tonsil T cells did not increase CD23/Fc epsilon RII expression. The expression of CD23/Fc epsilon RII mRNA was detected in RNA prepared from a tonsil T-cell-enriched population by Northern blot analysis.

T-cell and antibody response to Parietaria judaica allergenic fractions in atopic and nonatopic individuals

The in vitro proliferative response to separated immunologically relevant components of Parietaria judaica pollen extract (PjE) was investigated by proliferation assay and limiting dilution analysis, in peripheral blood mononuclear cells from Parietaria-allergic subjects and nonallergic controls. In the same subjects, the profile of the antibody response to the PjE fractions was also studied by immunoblotting to evaluate the functional significance of allergen-induced T-cell activation in the two groups. The estimated frequency of PjE-reactive T cells in peripheral-blood mononuclear cells was low in both groups. No difference was found between the Parietaria-allergic subjects and nonallergic controls. To assess the overall contribution to the cellular response of PjE components of different molecular weights, we separated the extract by the SDS-PAGE technique, and the fractions were blotted onto nitrocellulose and solubilized. Almost all the 14 fractions tested induced T-cell proliferation, at different degrees of magnitude. Responses were similar in the allergic subjects and nonallergic controls. Immunoblotting demonstrated specific IgG antibodies to the 14 PjE fractions not only in the allergic subjects, but also in the healthy controls, whereas IgE antibodies were found, as expected, only in the sera from atopic subjects. These findings indicate that PjE fractions elicit similar T-cell activation and IgG production in allergic and normal subjects.