Aspergillus oryzae reduces IgE binding ability of allergenic egg white proteins

摘要

Egg white proteins are one of the major allergens. The objective of this study was to investigate the effect of Aspergillus oryzae cultivation on IgE binding ability of egg white proteins. Effect of A. oryzae on egg white proteins was determined using ninhydrin method,SDS-PAGE, ELISA, fluorescence FITC labeling, MALDITOF-MS and LC-MS/MS analysis. Adding mycelium of A. oryzae ATCC 1011 and 16868 substantially reduced the IgE binding ability of acidified egg white after 24 h incubation. The binding capacity of egg white proteins to IgE in plasma from four egg allergy patients was almost completely lost after incubation with mycelium of ATCC16868. Results from SDS-PAGE, free amino acid analysis,MALDI-TOF-MS and LC-MS/MS indicated that there was no substantial protein degradation during incubation.Therefore, the reduction of IgE binding ability of egg white proteins during A. oryzae treatment was probably due to a loss of ~1700 Da mass including a fragment of the ovomucoid N terminus.