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Vacuolar Serine Protease Major Allergen of Fusarium Proliferatum
Saturday, March 5, 2016
South Exhibit Hall H (Convention Center)
Horng-Der Shen, Hsiao-Yun Tai, Chang-Ching Yeh, Keh-Gong Wu
Rationale:  Fusarium species are prevalent airborne fungi and recognized as causative agents of human respiratory atopic disorders. The purpose of this study is to identify and characterize important allergens of F. proliferatum.

Methods:  IgE-reacting F. proliferatumcomponents were identified by immunoblot. Characterization of allergens and determination of IgE cross-reactivity were performed by cDNA cloning and immunoblot inhibition studies.

Results: The 36.5 kDa IgE-binding component of F. proliferatum reacted with a monoclonal antibody FUM20 against fungal vacuolar serine protease allergens. The cDNA of F. proliferatum vacuolar serine protease (Fus p 9.0101) was cloned. Nine serum samples known previously IgE-binding against the vacuolar serine protease allergen of Penicillium chrysogenum (Pen ch 18) showed IgE immunoblot reactivity against rFus p 9.0101. The purified rFus p 9.0101 can inhibit IgE and FUM20-binding against the 36.5 kDa component of F. proliferatum. Thus, a novel and important F. proliferatum vacuolar serine protease allergen (Fus p 9.0101) was identified. The rPen ch 18 can inhibit IgE-binding against rFus p 9.0101. It indicates that IgE cross-reactivity between the Fusarium and the Penicilliumvacuolar serine protease allergens also exists. Both rFus p 9.0101 K88A and rPen ch 18 K89A mutants did not inhibit IgE-binding against rFus p 9.0101. Lys88 was considered a critical core amino acid in IgE-binding against Fus p 9.0101 and a residue responsible for IgE cross-reactivity between Fus p 9.0101 and Pen ch 18 allergens.

Conclusions: Our results indicate vacuolar serine protease is an important allergen of F. proliferatum and an IgE cross-reactive major pan-fungal allergen.