Extracellular antigens of Micropolyspora faeni grown in synthetic medium.

Extracellular antigens were prepared by growing Micropolyspora faeni in a new synthetic medium (SMSL), and this antigenic preparation was compared with antigens obtained by the double-dialysis method. These two preparations were tested against pooled sera from farmer's lung patients and rabbits immunized with these antigens by the agar-gel double-diffusion, immunoelectrophoresis, and two-dimensional immunoelectrophoresis methods. The immunological cross-reactivity between M. faeni strains of diverse origin and between other species of thermophilic actinomycetes associated with hypersensitivity pneumonitis was also investigated. The usefulness of two-dimensional immunoelectrophoresis in the comparison and standardization of antigens is discussed.