The Preparation and Chemical Composition of Fractions from Aspergillus fumigatus Wall and Protoplasts Possessing Antigenic Activity

Abstract

A detergent-soluble fraction was prepared from the fragmented wall of A. fumigatus mycelium using the non-ionic detergent Triton X-100 and a wall-free extract was prepared from the same source in the form of protoplasts, released by a lytic enzyme system from Trichoderma harzianum. These extracts were examined by polyacrylamide gel electrophoresis and their detailed chemical composition was established. They were compared with the water-soluble fraction prepared from total mycelium, used routinely in this laboratory for serological tests. All fractions had immunological reactivity towards an antiserum prepared in rabbits against this water-soluble fraction of the mycelium, as shown by double diffusion. Protein and carbohydrate moieties appear involved in the antigenic sites, with carbohydrate reactivity predominantly associated with the protoplast fraction. The fact that all preparations contained at least 1 common antigenic determinant, as judged by lines of identity to a single antiserum, is discussed in relation to antigen location. [This may be important in the development of serodiagnostic techniques for human aspergillosis].