Variability of antigenicity/allergenicity in different strains of Alternaria alternata.

Biochemical and immunological properties were studied in crude mould extracts from 10 different strains of Alternaria alternata. The mould strains were grown on completely synthetic medium and harvested under identical conditions. The biochemical and immunological analyses (protein content, carbohydrate content, IEF, RAST-inhibition, CIE/CRIE and the content of a major allergen) showed significant variations between the individual strains of A. alternata. 32 antigens were identified in the CIE pattern of A. alternata and 19 different allergens were identified in CRIE analysis (1 major, 7 intermediate and 6 minor allergens). There was a significant variation in the content of the major A. alternata allergen (Ag-8, partially identical to Alt-I) between the different individual strains. Furthermore, a considerable variation in the content of Ag-8 was observed for a specific strain cultivated at different occasions under identical cultivation conditions during a time period of 3 years.