Release of antigens and allergens during shake-culture of Aspergillus fumigatus

The appearance of IgG and IgE binding components in the medium of shake cultures of Aspergillus fumigatus has been studied. Cultures were grown in synthetic asparagine medium at 35 degrees C and flasks harvested in duplicate 1, 2, 3, 4, 7 and 14 days after inoculation. The pH of the medium dropped from its initial value of 5.5 to pH 3, and then after 4 days gradually increased up to pH 7.5 in the 14-day medium. The weight of mycelium, after an initial peak followed by a slight decline, increased as the pH of the medium increased. Components able to bind IgG and IgE from pooled ABPA sera were detected by crossed immunoelectrophoresis/self-crossed radioimmunoelectrophoresis within 24 h of growth, but maximal release of both antigens and allergens coincided with the increase in pH of the medium and was seen in the 14-day culture filtrate. Two recognised "major" antigens, Ag 7 and Ag 13, detected using the relevant monospecific antisera, were present in the culture medium after 14 days of growth and similarly for Ag 3, the major allergen, although another allergen, Ag 1, was identified in the 1-day extract. None of the culture filtrates was found to contain the "C-substance" polysaccharide.