Fusarium solani major allergen peptide IV-1 binds IgE but does not releasehistamine

Background Fusarium solani (FS) is an important allergen source afflicting 4% of the nasobronchial allergy patients. Fus s I-3596*, a 65 kDa major gly coprotein allergen of FS reacts with 95% fungus sensitive patients. Objectives To purify and characterize a potent peptide from Fus s 1(3596)* which may be useful for therapeutic purposes. Methods The 65 kDa protein was sequentially cleaved with trypsin and cyanog en bromide (CNBr). The cleaved products were purified on reverse phase high performance liquid chromatography (rpHPLC) column and functionally charact erized by in vitro and in vivo methods for its IgE binding and histamine re lease. Results The protein on cleavage showed 11 peaks (I to XI). Of these, peaks I, III, IV and V were highly allergenic as determined by IgE ELISA. These p eaks were further purified and peptide IV-1 was most potent in comparison t o other peptides by ELISA-inhibition. This peptide showed IgE binding but c ould not evoke intradermal response in Fusarium-sensitive patients. Heparin ized blood challenged with peptide IV-1 does not release histamine. Preincu bation of heparinized blood with peptide IV-1 and challenging with crude ex tract blocked histamine release in a dose dependent manner. Conclusion Peptide IV-1 binds to IgE but does not release histamine, demons trating its potential use in therapy of Fusarium-allergic patients.