Antibody binding of deletion mutants of Asp f 2, the major Aspergillus fumigatus allergen

Asp f 2, a 268 amino acid major allergen from Aspergillus fumgatus (Af) dem onstrated nine linear IgE binding regions, It is not known whether any of t hese linear epitopes are also conformatory epitopes. Hence, we constructed deletion mutants of Asp f 2 devoid of one or more epitopes, and the IgE bin ding of these proteins with sera from patients with ABPA was compared with the full-length Asp f 2 expressed in E. coli and Pichia. The Pichia express ed protein reacted weakly with IgE, but strongly with IgG of ABPA sera comp ared to E. coli expressed Asp f 2, Weak IgE binding only was seen when the C-terminal or N-terminaI was deleted, while depletion of both ends negated all reactivity. The monoclonal antibody IL-B8 and IgE and IgG of ABPA sera bound significantly to the Asp f 2 E-4 fragment indicating that the major B -cell epitope is located at the N-terminal end of Asp f 2, (C) 2000 Academi c Press.