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Fungal allergens from important allergenic fungi imperfecti
A Cruz1, M Saenz de Santamaría, J Martínez
1R&D Department, Industrial Farmacéutica y de Especialidades, S.A. Bilbao, Spain.
Abstract:
Occurrence of several fungal species in the environment seems to be related to hypersensitivity disorders in humans. Fungal allergen studies reported in the literature are reviewed regarding to Aspergillus, Alternaria, Penicillium and Cladosporium genera. In this paper, we study by means of in vivo (Skin Prick Test) and in vitro (RAST and immunoblotting) the classical question of the best source of allergenic material using a population of asthmatic patients sensitized to different mould genera. In Alternaria alternata, RAST values are considerably higher in metabolic extracts (culture filtrate) than in somatic ones (myceliar). In Alternaria alternata and Penicillium chrysogenum, low molecular weight allergens (< 30 kDa) show higher IgE-binding activity in culture filtrate extracts. In Aspergillus fumigatus we find some relevant allergens in the mycellium. Different fractions have also been used in skin tests and culture filtrate extracts showing higher potency than myceliar ones, what is in agreement with the former results. We found in Penicillium chrysogenum that the 67 kDa allergen, similar to what described by Shen et al (1991), showed inespecific binding to anti-IgE conjugate used in the development of the immunoblotting technique. Whether or not this component could be a major allergen is discussed. We discuss about the importance of the biology of fungi in the sensitization and development of mould allergy.
Insights
Fungal extracts from culture filtrates, particularly for Alternaria alternata and Penicillium chrysogenum, are more potent sources of allergens than mycelial extracts. This finding is crucial for understanding and diagnosing mould allergy in asthmatic patients.
Area of Science:
- Clinical Immunology
- Mycology
- Allergology
Background:
- Environmental fungal species are linked to human hypersensitivity disorders.
- Previous studies have reviewed fungal allergens from Aspergillus, Alternaria, Penicillium, and Cladosporium genera.
- The optimal source of allergenic material for diagnosing mould allergy remains a key question.
Purpose of the Study:
- To compare the allergenic potency of metabolic (culture filtrate) versus somatic (mycelial) extracts from common mould genera.
- To investigate the role of low molecular weight allergens (< 30 kDa) in mould sensitization.
- To evaluate the diagnostic utility of different fungal extract fractions in asthmatic patients.
Main Methods:
- In vivo testing using Skin Prick Test (SPT).
- In vitro testing including Radioallergosorbent Test (RAST) and immunoblotting.
- Analysis of patient sera from asthmatic individuals sensitized to various mould genera.
Main Results:
- Metabolic extracts of Alternaria alternata showed significantly higher RAST values compared to somatic extracts.
- Low molecular weight allergens (< 30 kDa) in Alternaria alternata and Penicillium chrysogenum culture filtrates exhibited greater IgE-binding activity.
- Culture filtrate extracts demonstrated higher potency in skin tests than mycelial extracts for Aspergillus fumigatus.
- A 67 kDa component in Penicillium chrysogenum showed non-specific binding, prompting discussion about its role as a major allergen.
Conclusions:
- Culture filtrate extracts are generally superior to mycelial extracts for diagnosing mould allergy.
- Understanding fungal biology and allergen composition is vital for effective mould allergy management.
- Further research is needed to clarify the significance of specific fungal components, such as the 67 kDa allergen in Penicillium chrysogenum.