MOLECULAR-CLONING OF IGE-BINDING FRAGMENTS OF ALTERNARIA-ALTERNATA ALLERGENS

Exposure to the hyphomycete Alternaria alternata is recognized as an i mportant risk factor for asthma. IgE immunoblotting has been used to c atalogue the number and hi, of allergens in A. alternata extracts, wit h estimates ranging from 10 to 30, although few are present in nearly all extracts studied. Several A. alternata allergens have been cloned, including a subunit of the major allergen Alt a 1, ribosomal P2 phosp hoprotein, aldehyde dehydrogenase and a yeast YCP4 homolog. We have cl oned two sequences encoding IgE-binding fragments of allergens from an A. alternata lambda gt11 cDNA library using pooled atopic sera from A . alternata-sensitive individuals. One is homologous to a region near the C-terminus of hsp70 from Cladosporium herbarum; a near-complete is oallergen variant of A. alternata ribosomal P2 protein was also cloned . Their lacZ fusion proteins had reactivities of 5 and 14%, respective ly, with individual atopic sera, indicating that the corresponding all ergens are both minor. This study describes one new A. alternata aller gen candidate and implicates ribosomal P2 protein as an allergen thtat is stable between independently isolated clones.