The preparation and chemical composition of fractions from Aspergillus fumigatus wall and protoplasts possessing antigenic activity.

A detergent-soluble fraction was prepared from the fragmented wall of Aspergillus 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, which is 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. Both protein and carbohydrate moieties appear to be involved in the antigenic sites, with carbohydrate reactivity predominantly associated with the protoplast fraction. The fact that all preparations contained at least one common antigenic determinant, as judged by lines of identity to a single antiserum, is discussed in relation to antigen location.